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Ikaite and pseudomorphs thereafter (“glendonites”) are a potentially powerful tool for palaeoclimatic studies, as a low-temperature proxy. However, much uncertainty still surrounds the drivers of ikaite formation, in particular prerequisite thermal and chemical conditions. Furthermore, the ikaite toglendonite transformation is not fully understood, and it was unclear which calcite phases in glendonites were ikaite-derived and which were later diagenetic calcites. This leads to difficulties in choosing which phase to analyse in order to reconstruct the original ikaite growth environmental conditions. Petrographicexamination of air-transformed ikaite from the Isatkoak Lagoon in Utqiaġvik, Alaska, confirms that both ’Type I’ and ’Type II’ calcite phases seen in glendonites are directly derived from ikaite breakdown and not from secondary sources. Clumped isotope temperature reconstructions for transformed ikaites from Utqiaġvik, and comparison to Recent glendonites from the White Sea, Russia, confirm that clumped isotope thermometry may be used to reconstruct ikaite growth temperatures, whilst stable isotopes and minor elemental analysis reveal that a range of geochemical conditions characterise ikaite growth sites

“The huge greate Oke was once a plant.” This observation, found in Timothy Kendall’s anthology Flower of epigrammes (1577), seems to state the obvious: trees do grow out of smaller (and frailer) plants and are subject to time. Yet this image is far from the emblematic representation of the oak, inherited from the Bible, which was often used in early modern poetry or political theory. Traditionally, the oak was the tree of Jupiter and connoted strength, immutability, and majesty, thus making it an ideal royal symbol (with the cedar). However, as Andrew McRae notes, “the politics of the oak—and of trees more generally—were [then] by no means as settled as it would become in a later period.” (2012) This then allowed for all sorts of rhetorical and semantic play, in particular in late Elizabethan history plays which depict the troubled reigns of contested kings. With a focus on the anonymous play Thomas of Woodstock (c. 1591-1595), I would like to explore how royal symbols such as the oak (and the cedar) are manipulated and subverted on stage. Like Kendall’s epigram, the play insists on the precarious nature of trees, both real and symbolic, showing how inadequate and artificial rhetorical tropes can be. Deprived of its emblematic and specific quality, the actual tree reappears behind the symbol. That symbol can then be reassigned to other potential candidates, which allows the play to challenge essential tenets of royal orthodoxy such as the king’s uniqueness., Dans l’anthologie Flowers of epigrammes, publiée en 1577 par Timothy Kendall, l’une des épigrammes consacrées au passage du temps s’ouvre par ce qui peut sembler une évidence : « The huge greate Oke was once a plant ». Mais ce premiers vers, qui rappelle les âge de la vie du chêne en soulignant sa faiblesse initiale, n’est pas sans originalité à cette époque. L’imagerie végétale est fréquemment utilisée dans les discours poétiques et politiques mais reste en effet fortement caractérisée par une stylisation emblématique héritée de la Bible qui tend à figer les éléments naturels en symboles immuables (Harrison, 1998). Le chêne notamment – l’arbre de Jupiter, robuste et majestueux – y est ainsi fréquemment associée à la figure royale. Mais comme le rappelle Andrew McRae, à cette époque, « the politics of the oak—and of trees more generally—were by no means as settled as it would become in a later period. » (2012) Si l’arbre est un trope rhétorique, il n’est ainsi pas étonnant qu’il soit soumis à toute forme de manipulation voire de détournement. Or c’est précisément cette instabilité sémantique dont se saisissent bon nombre de pièces historiques de la fin de l’ère élisabéthaine, notamment la pièce anonyme Thomas of Woodstock (c. 1591-1595). Souvent lue comme un préquel du Richard II de Shakespeare, cette pièce propose un discours sur les arbres, qu’ils soient réels ou symboliques, qui met en évidence non pas leur force mais leur fragilité. Je souhaite notamment montrer que cette pièce ne se cantonne pas à l’image stylisée et immuable du chêne comme emblème d’une royauté solide et majestueuse mais la complexifie et l’enrichit. D’une part, elle en montre l’artificialité rhétorique : il s’agit d’une représentation voire d’un modèle qui ne correspond que peu à la personne du souverain, ici le jeune Richard II. D’autre part elle témoigne de ses possibilités de réappropriation – potentiellement subversive – par le langage : l’image perd de sa singularité en se voyant réattribuée à d’autres figures non royales voire en étant diluée dans une masse arboricole indifférenciée.

The Eocene Oligocene Transition (EOT) 34 million years ago (Ma), was characterized by a climate shift from a largely ice-free greenhouse world to an icehouse climate. The colder Oligocene period included several cooling episodes, defining the bases of a s-Atlantic region, some of these cooling episodes are associated with appearance intervals of the dinocyst species Svalbardella clausii, and Svalbardella cooksoniae. Here we present newly generated dinocyst, calcareous nannofossil, XRF and TEX86 proxy records across the upper Eocene to upper Oligocene from DSDP Site 112, southern Labrador Sea (latitude 54°N; Cores 13 to 5). The studied cores penetrate a deep-sea pelagic succession representing an interval of ~40 to 26.5 Ma. Our study reveals major depositional changes in the region of Site 112 across the EOT, including a decrease in the relative abundance of oceanic dinocysts (Impagidinium spp.), a decrease in carbonate content, higher siliciclastic delivery and grain coarsening. Furthermore, in the early Chattian we observe a high abundance of the potentially cold-water dinocyst S. clausii (up to 16% of the total dinocyst assemblage), possibly related to the Oi-2b cooling event. The preliminary results of micro-Fourier transform infrared (FTIR) spectroscopy (a method for identifying macromolecular cell compositions in algal cells, and thus nutritional ecologies) in three morphologically similar Eocene and Oligocene dinocyst taxa (S. clausii, S. cooksoniae and Palaeocystodinium golzowense) suggest that they had similar feeding strategies. However, subtle differences in the resulting FTIR spectra indicate some geochemical distinctions between them. The affinity of S. clausii to colder surface waters is tested by comparison of its distribution to the TEX86-derived sea surface temperature record.

The Lower Cretaceous Tuxen (lower Hauterivian – upper Barremian) and Sola (upper Barremian – Albian) Formations in the Danish Central Graben (North Sea) constitute one of the oldest chalk successions recorded globally, but have received little attention with regards to sedimentary facies and depositional processes. This study presents the first comprehensive carbonate facies analysis of the succession, retrieved from seven drill cores from the Valdemar and Adda Fields. A total of 50 facies are identified, based on a continuum of six lithologies ranging from chalk to marlstone and tuffaceous siltstone to sandstone that display eight different sedimentary structures or fabrics, and two redox-associated lithological color variations (green and red) in the Adda Field. The eight sedimentary structures record: (i) comprehensive bioturbation of homogeneous sediment during fully oxygenated benthic conditions and low sedimentation rates; (ii) a similar bioturbation process but in heterogeneous sediment with lithological contrasts permitting visible burrows to form, perhaps due to rhythmic alternation between pelagic (clay-poor) and hemipelagic (clay-rich) sedimentation; (iii) pelagic to hemipelagic suspension settling in dysoxic to anoxic bottom-water conditions; (iv) patchy cementation of the shallow sea bed during incipient hardground formation; (v) reworking of bioclasts and chalk intraclasts by bottom or wave-induced currents and cohesive debris flows; (vi) pressure solution during late burial diagenesis; (vii) shear deformation by intense plastic deformation of unlithified sediment from limited lateral displacement; and (viii) silicification during burial diagenesis. The facies distribution indicates that active tectonism took place prior to the onset of anoxia that resulted in deposition of the Munk Marl Bed, which in the Valdemar Field was followed by tectonic waning and repeated anoxia. The Valdemar Field constituted a basinal depocenter and was flanked to the east by an early inversion high in the Adda Field characterized by condensation and bypass. The Fischschiefer Member represents a return to prevailing anoxia, consistent with global records of the early Aptian Oceanic Anoxic Event 1a (OAE-1a).

Large Igneous Provinces (LIPs) have caused significant environmental perturbations, including global warming and oceanic anoxia. At least five mass extinction events throughout Earth’s history temporally coincide with the occurrence of LIPs. Geochemical proxies for volcanism in sediments deposited at the time of LIP events can potentially link the volcanic record with the record of environmental change and extinction at We present ICP-MS trace element data from the Fur section in Denmark, where ash layers related to NAIP volcanism are interbedded with sediments deposited immediately after the PETM carbon isotope excursion. Systematic differences in trace element concentrations between ash layers and sediments indicate the potential value of arsenic (As), antimony (Sb), tellurium (Te), rhenium (Re), and thallium (Tl) as volcanic proxies. These elements are enriched in the sediment layers compared to the ashes and correlate with Hg/TOC. In particular, we observe elevated concentrations in Te (up to 600 ppb), compared to the average continental crustal value of about 3 ppb. Leaching of samples with dilute acid suggests that ash particles have degassed Te during eruption, whereas the sediments which were deposited more slowly, incorporate Te in a loosely bound form consistent with an atmospheric origin. We conclude that these trace elements are valuable proxies for the reconstruction of past volcanism.

Seasonal variability in sea surface temperatures plays a fundamental role in climate dynamics and species distribution. Seasonal bias can also severely compromise the accuracy of mean annual temperature reconstructions. It is therefore essential to better understand seasonal variability in climates of the past. Many reconstructions of climate in deep time neglect this issue and rely on controversial assumptions, such as estimates of sea water oxygen isotope composition. Here we present absolute seasonal temperature reconstructions based on clumped isotope measurements in bivalve shells which, critically, do not rely on these assumptions. We reconstruct highly precise monthly sea surface temperatures at around 50 °N latitude from individual oyster and rudist shells of the Campanian greenhouse period about 78 million years ago, when the seasonal range at 50 °N comprised 15 to 27 °C. In agreement with fully coupled climate model simulations, we find that greenhouse climates outside the tropics were warmer and more seasonal than previously thought. We conclude that seasonal bias and assumptions about seawater composition can distort temperature reconstructions and our understanding of past greenhouse climates. Mid-latitude sea surface temperatures during the Campanian greenhouse period 78 million years ago were warmer and more seasonal than thought, suggests a reconstruction at monthly timescales based on individual oyster and rudist shells.

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Seasonal variability in sea surface temperatures plays a fundamental role in climate dynamics and species distribution. Seasonal bias can also severely compromise the accuracy of mean annual temperature reconstructions. It is therefore essential to better understand seasonal variability in climates of the past. Many reconstructions of climate in deep time neglect this issue and rely on controversial assumptions, such as estimates of sea water oxygen isotope composition. Here we present absolute seasonal temperature reconstructions based on clumped isotope measurements in bivalve shells which, critically, do not rely on these assumptions. We reconstruct highly precise monthly sea surface temperatures at around 50 °N latitude from individual oyster and rudist shells of the Campanian greenhouse period about 78 million years ago, when the seasonal range at 50 °N comprised 15 to 27 °C. In agreement with fully coupled climate model simulations, we find that greenhouse climates outside the tropics were warmer and more seasonal than previously thought. We conclude that seasonal bias and assumptions about seawater composition can distort temperature reconstructions and our understanding of past greenhouse climates.

Supplementary data belonging to the manuscript entitled: "First absolute seasonal temperature estimates for greenhouse climate from clumped isotopes in bivalve shells" by de Winter et al.

Eubaculites carinatus (Morton, 1834) Figure 10A–J, N–S Eubaculites carinatus (Morton, 1834) figs. 29–35 Baculites carinatus Morton, 1834: 44, pl. 13, fig. 1. Baculites lyelli d’Orbigny, 1847: pl. 1, figs. 3–7. Baculites tippaensis Conrad, 1858: 334, pl. 3, fig. 27. Baculites spillmani Conrad, 1858: 335, pl. 35, fig. 24. Baculites sheromingensis Crick, 1924: 139, pl. 9, figs. 1–3. Eubaculites lyelli (d’Orbigny, 1847). Kennedy, 1987: 195, pl. 27, figs. 5–8; pl. 32, figs. 13, 14 (with full synonymy). Eubaculites carinatus (Morton, 1834). Klinger and Kennedy, 1993: 218, text-figs. 7a–e, 21–30, 31a–g, 32– 35, 36e, f, 37, 38, 42a, 52g, h. Eubaculites carinatus (Morton, 1834). Kennedy and Cobban, 2000: 180, pl. 2, figs. 1–23, 27, 28; text figs. 3, 4 (with additional synonymy). Eu baculites carinatus (Morton, 1834). Kennedy et al., 2001: 168, fig. 4a, e. Eubaculites carinatus (Morton, 1834). Landman et al., 2004a: 35, fig. 15P, Q. Eubaculites carinatus (Morton, 1834). Landman et al., 2004b: 55, figs. 27–29, 30A, B, 33U–Y. Eubaculites carinatus (Morton, 1834). Landman et al., 2007a: 64, figs. 29–35. TYPE: The holotype, by monotypy, is ANSP 72866, the original of Morton (1834: pl. 13, fig. 1), from the Maastrichtian Prairie Bluff Chalk of Alabama. MATERIAL: Approximately 40 specimens in the AMNH collections in the top 1 m of the Corsicana Formation at AMNH locs. 3620 and 3621, and as reworked material in the upper portion of the first unit (mudstone-clast-bearing unit) of the overlying K-Pg event deposit at the base of the Kincaid Formation, AMNH loc. 3620. DESCRIPTION: Nearly all the specimens are crushed but bear weak to strong, slightly crescentic nodate swellings on the flanks. The largest specimen is AMNH 108203, which retains part of the body chamber. The whorl height at the broken end of the body chamber is 30.5 mm, suggesting that it is a macroconch. The only fully three-dimensional specimen is AMNH 111960 from the K-Pg event deposit. It is a fragment 58.0 mm long with a whorl height of 30.0 mm at its adoral end. It is completely septate suggesting that it is probably a macroconch. The dorsum is very broadly rounded, and the dorsolateral margin is fairly sharply rounded. The inner flanks are broadly rounded with maximum width at one-third whorl height. The outer flanks converge to a tabulate venter bordered by a shallow longitudinal groove on each side. The flanks bear two prominent nodate swellings and the venter is covered with transverse ribs that project slightly forward, producing a serrated appearance. REMARKS: Several specimens from the Corsicana Formation are associated with oysters and represent postmortem encrustations (fig. 5A, B). The whorl height of the largest specimen in our collection (30.5 mm) exceeds that of the largest specimen of this species at the ageequivalent Tinton Formation in Monmouth County, New Jersey (25.4 mm). However, the specimens in the Corsicana Formation do not approach the size of the largest specimens of this species from Argentina and Zululand, which are approximately 90 mm in whorl height (Klinger and Kennedy, 2001: 62). Our collection is too small to confirm the hypothesis of dimorphism in Eubaculites carinatus, as suggested by bimodal size distributions of specimens from South Africa and South American localities by Klinger and Kennedy (2001). OCCURRENCE: Top 1 m of the Corsicana Formation at AMNH locs. 3620 and 3621, and basal Kincaid Formation at AMNH loc. 3620. We also found specimens of Eubaculites carinatus 17.68–18.29 mbs and 20.12–20.73 mbs in the Mullinax-1 core, correlated to planktonic foraminiferal zone CF3. The species has also been recorded throughout an approximately 11 m succession of the Corsicana Formation at Brazos by Kennedy et al. (2001). This species is widely distributed and, according to Henderson et al. (1992: 153), “is a useful indicator of middle to late Maastrichtian age and represents the last widely distributed heteromorph taxon to appear in the stratigraphic record.” On the eastern Gulf Coastal Plain, it is reported from the Owl Creek Formation in Mississippi, Missouri, and Tennessee (Kennedy and Cobban, 2000) and the Prairie Bluff Chalk in Alabama and Mississippi (Cobban and Kennedy, 1995). On the Atlantic Coastal Plain, it occurs in the Tinton and New Egypt formations, and as reworked material in the Hornerstown Formation in Monmouth and Gloucester counties, New Jersey (Kennedy and Cobban, 1996; Landman et al., 2004b; 2007a) and in the Severn Formation in Prince Georges and Anne Arundel counties, Maryland (Kennedy et al., 1997; Landman et al., 2004). It has also been reported from southeastern and southwestern France, northern Spain, Austria, the Netherlands, Zululand (South Africa), Mozambique, Madagascar, South India, Western Australia, Chile, Argentina, and California (Klinger and Kennedy, 1993; Klinger et al., 2001)., Published as part of Witts, James D., Landman, Neil H., Garb, Matthew P., Irizarry, Kayla M., Larina, Ekaterina, Thibault, Nicolas, Razmjooei, Mohammad J., Yancey, Thomas E. & Myers, Corinne E., 2021, Cephalopods from the Cretaceous-Paleogene (K-Pg) boundary interval on the Brazos River, Texas, and extinction of the ammonites, pp. 1-52 in American Museum Novitates 2021 (3964) on pages 25-27, DOI: 10.1206/3964.1, http://zenodo.org/record/4566589, {"references":["Morton, S. G. 1834. Synopsis of the organic remains of the Cretaceous group of the United States. Illustrated by 19 plates, to which is added an appendix containing a tabular view of the Tertiary fossils hitherto discovered in North America. Philadelphia: Key and Biddle.","Conrad, T. A. 1858. Observations on a group of Cretaceous fossil shells found in Tippah County, Mississippi, with descriptions of 56 new species. Journal of the Academy of Natural Sciences of Philadelphia (Series 2) 3: 275 - 298.","Crick, G. C. 1924. On Upper Cretaceous Cephalopoda from Portugese East Africa. Transactions of the Geological Society of South Africa 26: 130 - 140.","Kennedy, W. J. 1987. The ammonite fauna of the type Maastrichtian with a revision of Ammonites colligatus Binkhorst, 1861. Bulletin de l'Institut Royal des Sciences Naturelles de Belgique 56: 151 - 267.","Klinger, H. C., and W. J. Kennedy. 1993. Cretaceous faunas from Zululand and Natal, South Africa. The heteromorph ammonite genus Eubaculites Spath, 1926. Annals of the South African Museum 102: 185 - 264.","Kennedy, W. J., and W. A. Cobban. 2000. Maastrichtian (Late Cretaceous) ammonites from the Owl Creek Formation in northeastern Mississippi, U. S. A. Acta Geologica Polonica 50: 175 - 190.","Kennedy, W. J., A. S. Gale, and T. A. Hansen. 2001. The last Maastrichtian ammonites from the Brazos River sections in Falls County, Texas. Cretaceous Research 22: 163 - 171.","Landman, N. H., R. O. Johnson, and L. E. Edwards. 2004 a. Cephalopods from the Cretaceous / Tertiary boundary interval on the Atlantic coastal plain, with a description of the highest ammonite zones in North America. Part 1, Maryland and North Carolina. American Museum Novitates 3454: 1 - 64.","Landman, N. H., R. O. Johnson, and L. E. Edwards. 2004 b. Cephalopods from the Cretaceous / Tertiary boundary interval on the Atlantic coastal plain, with a description of the highest ammonite zones in North America. Part 2, Northeastern Monmouth County, New Jersey. Bulletin of the American Museum of Natural History 287: 1 - 107.","Landman, N. H., R. O. Johnson, M. P. Garb, L. E. Edwards, and F. T. Kyte. 2007 a. Cephalopods from the Cretaceous / Tertiary boundary interval on the Atlantic coastal plain, with a description of the highest ammonite zones in North America. Part 3, Manasquan River Basin, Monmouth County, New Jersey. Bulletin of the American Museum of Natural History 303: 1 - 122.","Henderson, R. A., W. J. Kennedy, and K. J. Mcnamara. 1992. Maastrichtian heteromorph ammonites from the Carnarvon Basin, Western Australia. Alcheringa: an Australasian Journal of Palaeontology 16: 133 - 170.","Cobban, W. A., and Kennedy, W. J. 1995. Maastrichtian ammonites chiefly from the Prairie Bluff Chalk in Alabama and Mississippi. Memoir, the Paleontological Society 44: 1 - 40.","Kennedy, W. J., and W. A. Cobban. 1996. Maastrichtian ammonites from the Hornerstown Formation in New Jersey. Journal of Paleontology 70: 798 - 804.","Kennedy, W. J., W. A. Cobban, and N. H. Landman. 1997. Maastrichtian ammonites from the Severn Formation of Maryland. American Museum Novitates 3210: 1 - 30."]}

Discoscaphites mullinaxorum, new species Figure 14 Discoscaphites iris Conrad, 1858). Kennedy and Cobban, 2000: pl. 3, fig. 21. DIAGNOSIS: Small, closely coiled shell, with no gap between the phragmocone and body chamber; body chamber covered with thin, sharp, slightly flexuous lirae and four rows of tiny tubercles (umbilicolateral, flank, and two rows of ventrolateral tubercles); umbilicolateral and lateral tubercles are radially elongated. ETYMOLOGY: This species is named after Ronnie and Jackie Mullinax, who have generously granted permission to scores of geologists and paleontologists to explore and collect fossils on their ranch and ensured the preservation of key outcrops for further study. Without their help, the K-Pg sections along the Brazos River would not be as well known worldwide as they are today. TYPES: The holotype is AMNH 112086, a crushed microconch, from AMNH loc. 3620, from the top of the Corsicana Formation, Darting Minnow Creek, Falls County, Texas. The paratypes are AMNH 108188, 111958, and 112024, from the same locality. MATERIAL: A total of 10 specimens, all of which are crushed microconchs, from the top 1.5 m of the Corsicana Formation, AMNH loc. 3620 (Darting Minnow Creek), Falls County, Texas. MICROCONCH DESCRIPTION: LMAX averages 22.4 mm and ranges from 17.5 to 29.1 mm. The shell is closely coiled with a large umbilicus. The body chamber occupies approximately one-half whorl and terminates in a constricted aperture (fig. 14P). The whorl height gradually increases in passing from the phragmocone to the body chamber. The umbilical shoulder of the body chamber follows the curvature of the venter. The ornament on the phragmocone consists of broad indistinct ribs. The body chamber is covered with thin, sharp, slightly flexuous lirae, especially on the adoral one-half. The lirae become less flexuous, coarser, and more closely spaced near the aperture (fig. 14Q, R). Four rows of tubercles are present on the adoral one-half of the body chamber (fig. 14A, B, G, H). In the holotype, the umbilicolateral tubercles are bullate and increase in size toward the aperture. They are perched on the umbilical shoulder (fig. 14G, H). The flank tubercles are tiny and radially elongate; they are generally not associated with the lirae. Because of crushing, the outer ventrolateral tubercles are not exposed in the holotype, but all four rows of tubercles are visible in AMNH 111958 (fig. 14A, B). The number of inner ventrolateral tubercles exceeds the number of flank tubercles. REMARKS: This species differs from Discoscaphites iris in its smaller size, its flatter flanks, and more delicate ornament. In particular, the tubercles in D. mullinaxorum are thin and radially elongate, whereas they are conical and pointy in D. iris. Although our collection consists only of microconchs, Kennedy and Cobban (2000: pl. 3, fig. 21) illustrated a small macroconch of this species, which they described as D. iris, from the upper part of the Owl Creek Formation in northeastern Mississippi. This macroconch is approximately 1.3× the average size of the microconchs in our collection. Discoscaphites mullinaxorum also resembles D. minardi Landman et al., 2004a, with its subdued ornament. However, the tubercles on the flanks of the body chamber in D. mullinaxorum are thin and radially elongate whereas they are rare or absent in D. minardi. In its subdued ornament, D. mullinaxorum also resembles D. conradi, but there are only four rows of tubercles in D. mullinaxorum compared to as many as six rows in D. conradi, sometimes even including a midventral row. OCCURRENCE: This species is rare in the upper part of the Corsicana Formation along the Brazos River and its tributaries in Falls County, Texas. Elsewhere on the Gulf Coastal Plain, it occurs in the Owl Creek Formation in Mississippi (Kennedy and Cobban, 2000).

Discoscaphites mullinaxorum, new species Figure 14 Discoscaphites iris Conrad, 1858). Kennedy and Cobban, 2000: pl. 3, fig. 21. DIAGNOSIS: Small, closely coiled shell, with no gap between the phragmocone and body chamber; body chamber covered with thin, sharp, slightly flexuous lirae and four rows of tiny tubercles (umbilicolateral, flank, and two rows of ventrolateral tubercles); umbilicolateral and lateral tubercles are radially elongated. ETYMOLOGY: This species is named after Ronnie and Jackie Mullinax, who have generously granted permission to scores of geologists and paleontologists to explore and collect fossils on their ranch and ensured the preservation of key outcrops for further study. Without their help, the K-Pg sections along the Brazos River would not be as well known worldwide as they are today. TYPES: The holotype is AMNH 112086, a crushed microconch, from AMNH loc. 3620, from the top of the Corsicana Formation, Darting Minnow Creek, Falls County, Texas. The paratypes are AMNH 108188, 111958, and 112024, from the same locality. MATERIAL: A total of 10 specimens, all of which are crushed microconchs, from the top 1.5 m of the Corsicana Formation, AMNH loc. 3620 (Darting Minnow Creek), Falls County, Texas. MICROCONCH DESCRIPTION: LMAX averages 22.4 mm and ranges from 17.5 to 29.1 mm. The shell is closely coiled with a large umbilicus. The body chamber occupies approximately one-half whorl and terminates in a constricted aperture (fig. 14P). The whorl height gradually increases in passing from the phragmocone to the body chamber. The umbilical shoulder of the body chamber follows the curvature of the venter. The ornament on the phragmocone consists of broad indistinct ribs. The body chamber is covered with thin, sharp, slightly flexuous lirae, especially on the adoral one-half. The lirae become less flexuous, coarser, and more closely spaced near the aperture (fig. 14Q, R). Four rows of tubercles are present on the adoral one-half of the body chamber (fig. 14A, B, G, H). In the holotype, the umbilicolateral tubercles are bullate and increase in size toward the aperture. They are perched on the umbilical shoulder (fig. 14G, H). The flank tubercles are tiny and radially elongate; they are generally not associated with the lirae. Because of crushing, the outer ventrolateral tubercles are not exposed in the holotype, but all four rows of tubercles are visible in AMNH 111958 (fig. 14A, B). The number of inner ventrolateral tubercles exceeds the number of flank tubercles. REMARKS: This species differs from Discoscaphites iris in its smaller size, its flatter flanks, and more delicate ornament. In particular, the tubercles in D. mullinaxorum are thin and radially elongate, whereas they are conical and pointy in D. iris. Although our collection consists only of microconchs, Kennedy and Cobban (2000: pl. 3, fig. 21) illustrated a small macroconch of this species, which they described as D. iris, from the upper part of the Owl Creek Formation in northeastern Mississippi. This macroconch is approximately 1.3�� the average size of the microconchs in our collection. Discoscaphites mullinaxorum also resembles D. minardi Landman et al., 2004a, with its subdued ornament. However, the tubercles on the flanks of the body chamber in D. mullinaxorum are thin and radially elongate whereas they are rare or absent in D. minardi. In its subdued ornament, D. mullinaxorum also resembles D. conradi, but there are only four rows of tubercles in D. mullinaxorum compared to as many as six rows in D. conradi, sometimes even including a midventral row. OCCURRENCE: This species is rare in the upper part of the Corsicana Formation along the Brazos River and its tributaries in Falls County, Texas. Elsewhere on the Gulf Coastal Plain, it occurs in the Owl Creek Formation in Mississippi (Kennedy and Cobban, 2000)., Published as part of Witts, James D., Landman, Neil H., Garb, Matthew P., Irizarry, Kayla M., Larina, Ekaterina, Thibault, Nicolas, Razmjooei, Mohammad J., Yancey, Thomas E. & Myers, Corinne E., 2021, Cephalopods from the Cretaceous-Paleogene (K-Pg) boundary interval on the Brazos River, Texas, and extinction of the ammonites, pp. 1-52 in American Museum Novitates 2021 (3964) on pages 35-37, DOI: 10.1206/3964.1, http://zenodo.org/record/4566589, {"references":["Conrad, T. A. 1858. Observations on a group of Cretaceous fossil shells found in Tippah County, Mississippi, with descriptions of 56 new species. Journal of the Academy of Natural Sciences of Philadelphia (Series 2) 3: 275 - 298.","Kennedy, W. J., and W. A. Cobban. 2000. Maastrichtian (Late Cretaceous) ammonites from the Owl Creek Formation in northeastern Mississippi, U. S. A. Acta Geologica Polonica 50: 175 - 190.","Landman, N. H., R. O. Johnson, and L. E. Edwards. 2004 a. Cephalopods from the Cretaceous / Tertiary boundary interval on the Atlantic coastal plain, with a description of the highest ammonite zones in North America. Part 1, Maryland and North Carolina. American Museum Novitates 3454: 1 - 64."]}

Discoscaphites iris (Conrad, 1858) Figure 12A–N Scaphites iris Conrad, 1858: 335, pl. 35, fig. 23. Scaphites iris Conrad. Whitfield, 1892: 265, pl. 44, figs. 4–7. Discoscaphites iris (Conrad). Stephenson, 1955: 134, pl. 23, figs. 23–30. Discoscaphites iris (Conrad, 1858). Kennedy and Cobban, 2000: 183, fig. 5; pl. 3, figs. 3–35. Discoscaphites iris (Conrad, 1858). Landman et al., 2004a: 39, figs. 15A, B, G–O, 17A–G, 18R. Discoscaphites iris (Conrad, 1858). Landman et al., 2004b: 71, figs. 34E–W (non A–D = Discoscaphites sphaeroidalis Kennedy and Cobban, 2000), 35, 36A–H, K–Q, S–Z, l–p, 37A–l, 38, 39A–P, 41A–D. Discoscaphites iris (Conrad, 1858). Landman et al., 2007a: 82, figs. 40-46, 47A–C. Discoscaphites iris. Keller et al., 2011: 85, fig. 3E. Discoscaphites iris (Conrad, 1858). Machalski et al., 2009: 375, fig. 2. Discoscaphites iris. Sessa et al., 2015: 15563, fig. 1A–C. Discoscaphites iris. Larina et al., 2016: 132, fig. 2B;145, fig. 14.1-26 Discoscaphites iris. Witts et al., 2018: 150, fig. 2C; 156, fig. 7A–U. Discoscaphites iris. Ferguson et al., 2019: 321. TYPE: The holotype is the original illustrated in Conrad, 1858 (335, pl. 35, fig. 23), labeled ANSP 50989, from the bluffs of Owl Creek, Tippah County, Mississippi. See Landman et al. (2004b) for a more complete description of this specimen. MATERIAL: A total of 27 specimens, mostly consisting of the body chamber or parts of the phragmocone and body chamber, plus numerous fragments, in the AMNH and UNM collections. The specimens are nearly equally divided between 13 microconchs and 14 macroconchs. All the specimens are crushed but retain their original aragonitic shell. The specimens are primarily derived from the top 1.5 m of the Corsicana Formation at AMNH locs. 3620, 3621, and 3968, but two (AMNH 111961 and AMNH 112037) also occur in the first (mudstoneclast-bearing) and second unit (ejecta-spherule-rich coarse sandstone) of the K-Pg event deposit at AMNH loc. 3620. D. iris is the most common scaphitid at Brazos, and as such, many of the abundant juvenile scaphitids present in these sections likely belong to this species, but because of their small size, they cannot be identified to the species level. MACROCONCH DESCRIPTION: Although the specimens are crushed, it is possible to measure the maximum length (LMAX). They range from 37.2 to 61.6 mm with most specimens falling between 50 and 55 mm (fig. 13). AMNH 112082 and 108182 are examples of small and large specimens, respectively. The ratio of the size of the largest specimen to that of the smallest is 1.7. Specimens are tightly coiled with a small umbilicus. The body chamber occupies approximately one-half whorl. In passing from the phragmocone to the shaft, the whorl height increases slightly, and then decreases again at the aperture. As in other scaphitid macroconchs, the umbilical shoulder of the body chamber is straight and occasionally shows a slight bulge. The aperture is constricted and the angle of the aperture averages 30°. The spire is covered by prorsiradiate ribs. They are broad and straight in AMNH 111959 and thin and slightly sinuous in AMNH 108178. Intercalation and branching occur at onethird and two-thirds whorl height. The ribs become broader and more widely spaced toward the adoral part of the spire. Two rows of ventrolateral tubercles are visible on the adapical part of the spire, although the outer row is difficult to discern because of crushing. An additional two rows of tubercles appear on the flanks soon thereafter. The ornament on the body chamber consists of four rows of tubercles—umbilicolateral, flank, and inner and outer ventrolateral tubercles. The tubercles occur on broad, low convex ribs that become more prominent on the hook. All the tubercles end in sharp points. The most prominent tubercles are the two umbilicolateral tubercles on the midshaft just below the umbilical margin (e.g., AMNH 198178). The flank tubercles are slightly smaller than the umbilicolateral tubercles and occur midway between the umbilicolateral and inner ventrolateral tubercles. MICROCONCH DESCRIPTION: Microconchs are, on average, smaller than macroconchs. Microconchs range in LMAX from 25.1 to 42.6 mm with most specimens falling between 30 and 35 mm (fig. 13). AMNH 111963 (fig. 10J) and 108186 (fig. 10N) are examples of small and large specimens, respectively. The ratio of the size of the largest specimen to that of the smallest is 1.7. In passing from the spire into the body chamber, the whorl height increases slightly. As a result, the umbilical seam follows the curvature of the venter. The body chamber is slightly uncoiled and occupies approximately one-half whorl. The ornamentation on the phragmocone consists of thin, slightly flexuous prorsiradiate ribs and two rows of ventrolateral tubercles. The prorsiradiate ribs on the body chamber are more poorly defined. They bear four rows of tubercles, of which the umbilicolateral tubercles are the most prominent. They are perched on the umbilical shoulder and attain their greatest height just adoral of midshaft. REMARKS: In comparison to specimens of Discoscaphites iris from New Jersey and the eastern Gulf Coastal Plain, the specimens from the Brazos River localities are larger (fig. 13). For example, LMAX of the largest macroconch from the Brazos River locality is 61.6 mm whereas it is 54.2 mm from New Jersey (Landman et al., 2007a). In contrast, the specimen from Libya is still larger, with an estimated diameter of 80 mm (Machalski et al., 2009). At least one specimen associated with oysters represents postmortem encrustations (fig. 5C, D). OCCURRENCE: This species is known from the upper part of the Corsicana Formation and the base of the Kincaid Formation along the Brazos River and its tributaries in Falls County, Texas. It has also been reported in the Mullinax-1 and Mullinax-3 cores from the Corsicana Formation in the same area (Keller et al., 2011). Elsewhere on the Gulf Coastal Plain, it occurs in the Owl Creek Formation in Mississippi, Tennessee, and Missouri (Stephenson, 1955; Sohl, 1960, 1964; Kennedy and Cobban, 2000). On the Atlantic Coastal Plain, it occurs in the upper part of the Tinton Formation and as reworked material at the base of the Hornerstown Formation, central Monmouth County; the upper part of the New Egypt Formation and as reworked material at the base of the Hornerstown Formation in northeastern and southwestern Monmouth County (Landman et al., 2007a); and the upper part of the Severn Formation in Kent and Anne Arundel counties, Maryland (Landman et al. 2004a). It is the name bearer of the Discoscaphites iris Zone in the Gulf and Atlantic Coastal Plains, where it represents the upper part of the upper Maastrichtian, corresponding to the upper part of calcareous nannofossil Subzone CC26b (Landman et al., 2004a; 2004b; 2007a; Larina et al., 2016). This species has also been reported from the upper Maastrichtian of northwest Libya (Machalski et al., 2009)., Published as part of Witts, James D., Landman, Neil H., Garb, Matthew P., Irizarry, Kayla M., Larina, Ekaterina, Thibault, Nicolas, Razmjooei, Mohammad J., Yancey, Thomas E. & Myers, Corinne E., 2021, Cephalopods from the Cretaceous-Paleogene (K-Pg) boundary interval on the Brazos River, Texas, and extinction of the ammonites, pp. 1-52 in American Museum Novitates 2021 (3964) on pages 29-33, DOI: 10.1206/3964.1, http://zenodo.org/record/4566589, {"references":["Conrad, T. A. 1858. Observations on a group of Cretaceous fossil shells found in Tippah County, Mississippi, with descriptions of 56 new species. Journal of the Academy of Natural Sciences of Philadelphia (Series 2) 3: 275 - 298.","Whitfield, R. P. 1892. Gasteropoda and Cephalopoda of the Raritan clays and Greensand marls of New Jersey. United States Geological Survey Monograph 18: 1 - 402.","Stephenson, L. W. 1955. Owl Creek (Upper Cretaceous) fossils from Crowley's Ridge, southeastern Missouri. United States Geological Survey Professional Paper 274: 97 - 140","Kennedy, W. J., and W. A. Cobban. 2000. Maastrichtian (Late Cretaceous) ammonites from the Owl Creek Formation in northeastern Mississippi, U. S. A. Acta Geologica Polonica 50: 175 - 190.","Landman, N. H., R. O. Johnson, and L. E. Edwards. 2004 a. Cephalopods from the Cretaceous / Tertiary boundary interval on the Atlantic coastal plain, with a description of the highest ammonite zones in North America. Part 1, Maryland and North Carolina. American Museum Novitates 3454: 1 - 64.","Landman, N. H., R. O. Johnson, and L. E. Edwards. 2004 b. Cephalopods from the Cretaceous / Tertiary boundary interval on the Atlantic coastal plain, with a description of the highest ammonite zones in North America. Part 2, Northeastern Monmouth County, New Jersey. Bulletin of the American Museum of Natural History 287: 1 - 107.","Landman, N. H., R. O. Johnson, M. P. Garb, L. E. Edwards, and F. T. Kyte. 2007 a. Cephalopods from the Cretaceous / Tertiary boundary interval on the Atlantic coastal plain, with a description of the highest ammonite zones in North America. Part 3, Manasquan River Basin, Monmouth County, New Jersey. Bulletin of the American Museum of Natural History 303: 1 - 122.","Machalski, M., J. W. M. Jagt, N. H. Landman, and J. Uberna. 2009. First record of the North American scaphitid ammonite Discoscaphites iris from the upper Maastrichtian of Libya. Neues Jahrbuch fur Geologie und Palaontologie Abhandlungen 254: 373 - 378.","Sessa, J. A., et al. 2015. Ammonite habitat revealed via isotopic composition and comparisons with cooccurring benthic and planktonic organisms. Proceedings of the National Academy of Sciences of the United States of America 112: 15562 - 15567.","Larina, E., et al. 2016. Upper Maastrichtian ammonite biostratigraphy of the Gulf Coastal Plain (Mississippi Embayment, southern USA). Cretaceous Research 60: 128 - 151.","Irizarry, K. M., M. P. Garb, J. D. Witts, A. Danilova, and N. H. Landman. 2018. Faunal analysis of the Cretaceous-Paleogene (K-Pg) mass extinction boundary, Brazos River, Texas. Munstersche Forschungen zur Geologie und Palaontologie 110: 57 - 58","Ferguson, K., K. G. Macleod, N. H. Landman, and J. A. Sessa. 2019. Evaluating growth and ecology in baculitid and scaphitid ammonites using stable isotope sclerochronology. Palaios 34: 317 - 329.","Sohl, N. F. 1960. Archaeogastropoda, Mesogastropoda and stratigraphy of the Ripley, Owl Creek, and Prairie Bluff Formations. United States Geological Survey Professional Paper 331 - A: 1 - 151.","Sohl, N. F. 1964. Neogastropoda, Opisthobranchia, and Basommatophora from the Ripley, Owl Creek, and Prairie Bluff Formations. United States Geological Survey Professional Papers 331 - B: 153 - 344."]}

Genus Eubaculites Spath, 1926 TYPE SPECIES: Baculites vagina Forbes var. ootacodensis Stoliczka, 1866: 199, pl. 90, figs. 14,?15, by original designation by Spath, 1926: 80., Published as part of Witts, James D., Landman, Neil H., Garb, Matthew P., Irizarry, Kayla M., Larina, Ekaterina, Thibault, Nicolas, Razmjooei, Mohammad J., Yancey, Thomas E. & Myers, Corinne E., 2021, Cephalopods from the Cretaceous-Paleogene (K-Pg) boundary interval on the Brazos River, Texas, and extinction of the ammonites, pp. 1-52 in American Museum Novitates 2021 (3964) on page 25, DOI: 10.1206/3964.1, http://zenodo.org/record/4566589, {"references":["Spath, L. F. 1926. New ammonites from the English chalk. Geological Magazine 63: 77 - 83.","Stoliczka, F. 1866. Ammonitidae, with revision of the Nautilidae. The fossil Cephalopoda of the Cretaceous rocks of southern India. Memoirs of the Geological Survey of India. Palaoentologica Indica (Series 3) 1: 155 - 216."]}

Discoscaphites sp. Figures 15, 16 MATERIAL: All sites we studied at the Brazos River localities yield many small juveniles of Discoscaphites (fig. 15). Because of their small size, it is impossible to identify them to a species level. DESCRIPTION: Juvenile specimens range in LMAX from 1.7 to 10.4 mm and retain part or all of their body chamber (fig. 15; table 1) Although the specimens preserve traces of the outer shell wall, the ornamentation is subdued or absent. Several specimens show exquisite details of the microornamentation of the embryonic shell (ammonitella; fig. 16). REMARKS: The presence of complete to nearly complete juveniles suggests that the animals lived at the site in which they are buried. All the specimens appear as isolated occurrences except for AMNH 63319, which occurs in a concentration of shell hash along with other juveniles and fish debris. OCCURRENCE: All specimens are from the upper portion of the Corsicana Formation just below the K-Pg boundary at AMNH locs. 3620 and 3621, Darting Minnow and Cottonmouth creeks, respectively. Lower jaws of Discoscaphites Figure 11E–J MATERIAL: Four isolated specimens (AMNH 108284, 108179, 108282, 63317) and one preserved in situ (AMNH 63312) from the top 1.25 m of the Corsicana Formation at AMNH loc. 3620 and AMNH loc. 3621, Darting Minnow and Cottonmouth creeks, Falls County, Texas. The specimens consist of the outer calcareous valve (aptychus), although three of them also retain traces of the inner black layer DESCRIPTION: Each valve is roughly triangular in outline. The ratio of valve length to valve width ranges from 1.4 to 1.9 in our sample. The symphysal edge is straight and forms a flange that increases in height posteriorly. The anterior margin is nearly straight, the lateral margin is broadly rounded, and the posterior margin is sharply rounded. The ventral surface of each valve is covered with small folds that parallel the posterior margin. Most of the jaws are preserved with only one valve exposed. However, in AMNH 63317 the two valves are folded folio style. As a result, the ventral surface of one valve and part of the dorsal surface of the other valve are exposed. AMNH 66312 occurs inside a very poorly preserved specimen of Discoscaphites iris surrounded by small oysters. The specimen of D. iris is 32.1 mm in maximum length, so that the ratio of LMAX to the length of the jaw is 2.3. REMARKS: These specimens are similar to the lower jaws of scaphites illustrated from Maastrichtian deposits of South Dakota (Landman and Waage, 1993: figs. 37–41, 167E–I) and northern Europe (Birkelund, 1982: pl. 2, figs. 6, 7; Birkelund, 1993: pl. 17, figs. 2–4; Machalski, 2005b: fig. 26)., Published as part of Witts, James D., Landman, Neil H., Garb, Matthew P., Irizarry, Kayla M., Larina, Ekaterina, Thibault, Nicolas, Razmjooei, Mohammad J., Yancey, Thomas E. & Myers, Corinne E., 2021, Cephalopods from the Cretaceous-Paleogene (K-Pg) boundary interval on the Brazos River, Texas, and extinction of the ammonites, pp. 1-52 in American Museum Novitates 2021 (3964) on pages 37-39, DOI: 10.1206/3964.1, http://zenodo.org/record/4566589, {"references":["Landman, N. H., and K. M. Waage. 1993. Scaphitid ammonites of the Upper Cretaceous (Maastrichtian) Fox Hills Formation in South Dakota and Wyoming. Bulletin of the American Museum of Natural History 215: 1 - 257.","Birkelund, T. 1982. Maastrichtian ammonites from Hemmoor, Niederelbe (NW-Germany). Geologisches Jahrbuch 61: 13 - 33.","Birkelund, T. 1993. Ammonites from the Maastrichtian White Chalk of Denmark. Bulletin of the Geological Society of Denmark 40: 33 - 81.","Machalski, M. 2005 b. Late Maastrichtian and earliest Danian scaphitid ammonites from central Europe: Taxonomy, evolution, and extinction. Acta Palaeontologica Polonica 50: 653 - 696."]}

Eutrephoceras sp. Figure 7 MATERIAL: One small phragmocone UNM 15495 from the Middle Sandstone Bed (Yancey, 1996; Hart et al., 2012), Kincaid Formation (Littig Member), from an outcrop just west of a culvert upstream of the waterfall section at AMNH loc. 3620. DESCRIPTION: The specimen is a wholly septate steinkern 31.6 mm in diameter with a whorl height of 26.5 mm at the adoral end. The septa are closely spaced with 13 septa in the last whorl. The specimen bears traces of another whorl. REMARKS: The holotype of Eutrephoceras dekayi ANSP 19484 is the original of Morton (1834: pl. 8, fig. 4), from the “marls of Monmouth and Burlington counties, New Jersey,” by subsequent designation by Whitfield (1892: 243, pl. 37, figs. 2, 3) and is illustrated by Landman et al. (2004a: 41, figs. 17–21). This species was more fully documented by Landman et al. (2017) who relied on conspecific material from the U.S. Western Interior, as Hyatt (1894) had done previously. They concluded that the species is early Maastrichtian, suggesting that younger forms (e.g., late Maastrichtian) should be carefully scrutinized to determine whether they conform to the description of this species. The present specimen is assigned to Eutrephoceras based on its size, shape, and suture pattern. However, because it is only a fragment of a phragmocone, it cannot be identified to species level. OCCURRENCE: This genus is worldwide and is reported from the Campanian to the Eocene. In Texas, it has been reported from the Upper Cretaceous (Campanian-Maastrichtian) Navarro Group of Hunt, Navarro, and Kaufman counties (Emerson et al., 1994), and the Eocene Cook Mountain Formation of Leon County (Miller, 1947). To our knowledge, UNM 15495 is the only reported specimen of Eutrephoceras from the Brazos River localities., Published as part of Witts, James D., Landman, Neil H., Garb, Matthew P., Irizarry, Kayla M., Larina, Ekaterina, Thibault, Nicolas, Razmjooei, Mohammad J., Yancey, Thomas E. & Myers, Corinne E., 2021, Cephalopods from the Cretaceous-Paleogene (K-Pg) boundary interval on the Brazos River, Texas, and extinction of the ammonites, pp. 1-52 in American Museum Novitates 2021 (3964) on pages 19-20, DOI: 10.1206/3964.1, http://zenodo.org/record/4566589, {"references":["Yancey, T. E. 1996. Stratigraphy and Depositional Environments of the Cretaceous-Tertiary boundary complex and basal Paleocene section, Brazos River, Texas. Gulf Coast Association of Geological Societies Transactions 46: 433 - 442.","Hart, M. B., et al. 2012. The Cretaceous-Paleogene boundary on the Brazos River, Texas: new stratigraphic sections and revised interpretations. Gulf Coast Association of Geological Societies 1: 69 - 80.","Morton, S. G. 1834. Synopsis of the organic remains of the Cretaceous group of the United States. Illustrated by 19 plates, to which is added an appendix containing a tabular view of the Tertiary fossils hitherto discovered in North America. Philadelphia: Key and Biddle.","Whitfield, R. P. 1892. Gasteropoda and Cephalopoda of the Raritan clays and Greensand marls of New Jersey. United States Geological Survey Monograph 18: 1 - 402.","Landman, N. H., R. O. Johnson, and L. E. Edwards. 2004 a. Cephalopods from the Cretaceous / Tertiary boundary interval on the Atlantic coastal plain, with a description of the highest ammonite zones in North America. Part 1, Maryland and North Carolina. American Museum Novitates 3454: 1 - 64.","Landman, N. H., J. W. Grier, J. K. Cochran, J. C. Grier, J. G. Petersen, and W. H. Towbin. 2017. Nautilid nurseries: hatchlings and juveniles of Eutrephoceras dekayi from the lower Maastrichtian (Upper Cretaceous) Pierre Shale of east-central Montana. Lethaia 51: 48 - 74.","Hyatt, A. 1894. Phylogeny of an acquired characteristic. Proceedings of the American Philosophical Society 32: 349 - 647.","Emerson, B. L., J. H. Emerson, R. A. Akers, and T. J. Akers. 1994. Texas Cretaceous ammonites and nautiloids. Houston: Paleontology Section, Houston Gem and Mineral Society, 439 pp.","Miller, A. K. 1947. Tertiary nautiloids of the Americas. Geological Society of America Memoirs 23: 1 - 234."]}

Discoscaphites sphaeroidalis Kennedy and Cobban, 2000 Figure 12O, P Discoscaphites sp. Stephenson, 1955: 135, pl. 23, figs. 20–22. Discoscaphites sphaeroidalis Kennedy and Cobban, 2000: 185, pl. 1, figs. 1–11, text-fig. 6 Discoscaphites sphaeroidalis Kennedy and Cobban, 2000. Kennedy et al., 2001: 169, fig. 4b, c. Discoscaphites iris (Conrad, 1858). Landman et al., 2004b: 71, fig. 34A–D. Discoscaphites sphaeroidalis Kennedy and Cobban, 2000. Landman et al., 2007a: 92, figs. 47D, 48. TYPE: The holotype is USNM 465615, a macroconch missing part of the hook. It is from the Owl Creek Formation at its type locality, 4 km northeast of Ripley, Tippah County, Mississippi. MATERIAL: The material from Brazos consists of six specimens, three of which are identifiable as adult microconchs (AMNH 108185, 111957, and 116345) and three of which are fragments of adult microconchs (AMNH 108174, 108184, and 133094) from the top of the Corsicana Formation in Darting Minnow and Cottonmouth creeks (AMNH locs. 3620 and 3621), Falls County, Texas. MICROCONCH DESCRIPTION: The three nearly complete specimens range in size from 31.6 to 36.1 mm. The phragmocone extends slightly below the line of maximum length and the body chamber occupies approximately one-half whorl. As shown in AMNH 116345 (fig. 12P), the aperture is constricted with a weak ventral projection. The ornamentation on the phragmocone is well preserved in AMNH 11957 (fig. 12O). The ribs are narrow, long, and uniformly spaced. They bear four rows of tubercles, of which the inner ventrolateral row is the most prominent. The ribs on the body chamber are weaker, but the tubercles are stronger than those on the phragmocone. The tubercles are widely spaced on the shaft and more closely spaced on the hook. Both rows of ventrolateral tubercles extend to the aperture. REMARKS: Because these specimens are crushed, no information is available about the shape of the whorl section, which is important for identifying this species and distinguishing it from Discoscaphites iris. However, the ornamentation on the phragmocone is well preserved and consists of narrow, long ribs, one of the defining features of this species. It is curious that our collection consists only of microconchs whereas other collections of this species contain both dimorphs (Kennedy and Cobban, 2000; Kennedy et al., 2001; Landman et al., 2007a). If macroconchs were present, they would be easily recognizable. Their absence is probably due to the small size of the collection. OCCURRENCE: This species is known from the upper part of the Corsicana Formation along the Brazos River and its tributaries in Falls County, Texas. Kennedy et al. (2001) reported it as occurring throughout the top ~ 8 m of the Corsicana Formation. Elsewhere on the Gulf Coastal Plain, it occurs in the Owl Creek Formation in Mississippi and Missouri (Stephenson, 1955; Kennedy and Cobban, 2000). On the Atlantic Coastal Plain, it occurs in the upper part of the Tinton Formation and as reworked material at the base of the Hornerstown Formation, central Monmouth County, and in the upper part of the New Egypt Formation and as reworked material at the base of the Hornerstown Formation in northeastern Monmouth County (Landman et al., 2007a)., Published as part of Witts, James D., Landman, Neil H., Garb, Matthew P., Irizarry, Kayla M., Larina, Ekaterina, Thibault, Nicolas, Razmjooei, Mohammad J., Yancey, Thomas E. & Myers, Corinne E., 2021, Cephalopods from the Cretaceous-Paleogene (K-Pg) boundary interval on the Brazos River, Texas, and extinction of the ammonites, pp. 1-52 in American Museum Novitates 2021 (3964) on pages 34-35, DOI: 10.1206/3964.1, http://zenodo.org/record/4566589, {"references":["Kennedy, W. J., and W. A. Cobban. 2000. Maastrichtian (Late Cretaceous) ammonites from the Owl Creek Formation in northeastern Mississippi, U. S. A. Acta Geologica Polonica 50: 175 - 190.","Stephenson, L. W. 1955. Owl Creek (Upper Cretaceous) fossils from Crowley's Ridge, southeastern Missouri. United States Geological Survey Professional Paper 274: 97 - 140","Kennedy, W. J., A. S. Gale, and T. A. Hansen. 2001. The last Maastrichtian ammonites from the Brazos River sections in Falls County, Texas. Cretaceous Research 22: 163 - 171.","Conrad, T. A. 1858. Observations on a group of Cretaceous fossil shells found in Tippah County, Mississippi, with descriptions of 56 new species. Journal of the Academy of Natural Sciences of Philadelphia (Series 2) 3: 275 - 298.","Landman, N. H., R. O. Johnson, and L. E. Edwards. 2004 b. Cephalopods from the Cretaceous / Tertiary boundary interval on the Atlantic coastal plain, with a description of the highest ammonite zones in North America. Part 2, Northeastern Monmouth County, New Jersey. Bulletin of the American Museum of Natural History 287: 1 - 107.","Landman, N. H., R. O. Johnson, M. P. Garb, L. E. Edwards, and F. T. Kyte. 2007 a. Cephalopods from the Cretaceous / Tertiary boundary interval on the Atlantic coastal plain, with a description of the highest ammonite zones in North America. Part 3, Manasquan River Basin, Monmouth County, New Jersey. Bulletin of the American Museum of Natural History 303: 1 - 122."]}

Sphenodiscus pleurisepta (Conrad, 1857) Figure 9B, C Ammonites pleurisepta Conrad, 1857: 159, pl. 15, fig. 1. Sphenodiscus lenticularis (Owen). Kellum, 1962: 68, pl. 4, figs. 3, 4; pl. 5, fig. 1; pl. 6, figs. 1, 2. Sphenodiscus pleurisepta (Conrad, 1857). Cobban and Kennedy, 1993: 58, figs. 1, 3t. Sphenodiscus pleurisepta (Conrad, 1857). Cobban and Kennedy, 1995: 12, fig. 8.5 (with full synonymy). Sphenodiscus pleurisepta (Conrad, 1857). Kennedy et al., 1996: 11, figs. 4A, 5–12. Sphenodiscus pleurisepta (Conrad, 1857). Kennedy et al., 1997: 9, figs. 9J, 11–14. Sphenodiscus pleurisepta. Larson et al., 1997: 91. Sphenodiscus pleurisepta (Conrad, 1857). Landman and Cobban, 2003: 17, figs. 12–15. TYPE: The holotype is USNM 9888, said to be from “Jacun, 3 miles below Laredo,” but is probably from Maverick County, Texas, in the Escondido Formation of the Rio Grande Region (Stephenson, 1941, 1955). MATERIAL: One nearly complete specimen when found, now fragmentary (AMNH 116378), from the Corsicana Formation 1.25 m below the K-Pg boundary at AMNH loc. 3620, Darting Minnow Creek, Falls County, Texas, and one fragmentary specimen (UNM 15489) from the basal unit (mudstone-clast-bearing conglomerate) of the K-Pg event deposit also at AMNH loc. 3620. DESCRIPTION: AMNH 116378 is a specimen with the body chamber preserved, ~ 12 cm in diameter. The body chamber bears a hole 12.1 mm in diameter. UNM 15489 is a fragment of the umbilical portion of a body chamber. Both show the characteristic rows of nodes on the smooth flanks that distinguish this species from S. lobatus. REMARKS: Like Spenodiscus lobatus, S. pleurisepta is rare at Brazos, although the presence of a complete specimen suggests that it may not have experienced postmortem floating. OCCURRENCE: The two specimens of Sphenodiscus pleurisepta come from the top 1.25 m of the Corsicana Formation and basal ~ 20 cm of the Kincaid Formation, Falls County, Texas. This species has also been reported from the Corsicana Formation in Navarro County, Texas (Kennedy and Cobban, 1993a; see also Stephenson, 1941, 1955). It occurs in the Escondido Formation in Texas (Böse, 1928) and northern Mexico. It also occurs in the Maastrichtian Cerro del Pueblo Formation of the Difunta Group at Rincón Colorado, Coahuila (Ifrim et al., 2004; Ifrim et al., 2005). On the eastern Gulf Coastal Plain, it occurs in the upper part of the Owl Creek Formation in Missouri, Mississippi, and Tennessee and in the Prairie Bluff Chalk in Alabama and Mississippi (Cobban and Kennedy, 1995). On the Atlantic Coastal Plain, it occurs in the top of the New Egypt Formation and as reworked material at the base of the Hornerstown Formation in Monmouth County, New Jersey (Weller, 1907; Reeside, 1962; Gallagher, 1993; Landman et al., 2004a, 2004b) and in the Severn Formation in Prince Georges and Kent Counties, Maryland (Kennedy et al., 1997). In the Western Interior, this species occurs in the Hoploscaphites birklundae Zone of the Pierre Shale in Meade and Pennington counties, South Dakota (Kennedy et al., 1996) and in the upper part of the Pierre Shale and Fox Hills Formation in Weld County, Colorado (Landman and Cobban, 2003). Despite possible postmortem drift of Sphenodiscus lobatus specimens, these new data suggest that both species of sphenodiscid cooccur in the Corsicana Formation of the Brazos River area immediately below the K-Pg boundary. Poorly preserved examples of both S. lobatus and S. pleurisepta are also found in the basal unit of the K-Pg event deposit itself. As noted above, this is different from the Maastrichtian deposits of the U.S. Western Interior, with S. pleurisepta present in the Hoploscaphites birklundae Zone, being replaced by S. lobatus in the overlying Hoploscaphites nicolletii Zone. A similar situation was noted by Ifrim et al. (2005), and Ifrim and Stinnesbeck (2010) in their studies of Maastrichtian ammonite faunas from Mexico. These authors suggested that the two sphenodiscid species may have inhabited slightly different environments, explaining why they are rarely found together in the same outcrop or bed. In the U.S. Gulf Coastal Plain, both species range to the top of the Maastrichtian (Landman et al., 2015), and appear to cooccur at three localities in the Discoscaphites iris Range Zone (fig. 6): in the Owl Creek Formation in Mississippi (AMNH loc. 3460) and Missouri (AMNH loc. 3458) (Larina et al., 2016) and the Corsicana Formation at Brazos., Published as part of Witts, James D., Landman, Neil H., Garb, Matthew P., Irizarry, Kayla M., Larina, Ekaterina, Thibault, Nicolas, Razmjooei, Mohammad J., Yancey, Thomas E. & Myers, Corinne E., 2021, Cephalopods from the Cretaceous-Paleogene (K-Pg) boundary interval on the Brazos River, Texas, and extinction of the ammonites, pp. 1-52 in American Museum Novitates 2021 (3964) on pages 23-24, DOI: 10.1206/3964.1, http://zenodo.org/record/4566589, {"references":["Conrad, T. A. 1857. Descriptions of Cretaceous and Tertiary fossils. In W. H. Emory (editor), Report on the United States and Mexican Boundary Survey. United States 34 th Congress, 1 st Session, Senate Ex Document 108 and House Ex Document 135 1 (2): 141 - 174.","Kellum, L. B. 1962. Upper Cretaceous mollusca from Niobrara County, Wyoming. Michigan Academy of Science and Arts Letters 47: 37 - 70.","Cobban, W. A., and Kennedy, W. J. 1995. Maastrichtian ammonites chiefly from the Prairie Bluff Chalk in Alabama and Mississippi. Memoir, the Paleontological Society 44: 1 - 40.","Kennedy, W. J., W. A. Cobban, and N. H. Landman. 1997. Maastrichtian ammonites from the Severn Formation of Maryland. American Museum Novitates 3210: 1 - 30.","Larson, N. L., S. D. Jorgensen, R. A. Farrar, and P. L. Larson. 1997. Ammonites and the other cephalopods of the Pierre Seaway. Tucson, AZ: Geoscience Press.","Landman, N. H., and W. A. Cobban. 2003. Ammonites from the upper part of the Pierre Shale and Fox Hills Formation of Colorado. American Museum Novitates 3388: 1 - 45.","Stephenson, L. W. 1941. The larger invertebrate fossils of the Navarro Group of Texas (exclusive of corals and crustaceans and exclusive of the fauna of the Escondido Formation). University of Texas Bulletin 4101: 1 - 641.","Stephenson, L. W. 1955. Owl Creek (Upper Cretaceous) fossils from Crowley's Ridge, southeastern Missouri. United States Geological Survey Professional Paper 274: 97 - 140","Kennedy, W. J., and W. A. Cobban. 1993 a. Maastrichtian ammonites from the Corsicana Formation in northeast Texas. Geological Magazine 130: 57 - 67.","Bose, E. 1928. Cretaceous ammonites from Texas and northern Mexico. Bulletin of the University of Texas, Bureau of Economic Geology and Technology, Austin 2748, 143 - 312.","Ifrim, C., W. Stinnesbeck, and J. G. Lopez-Oliva. 2004. Maastrichtian cephalopods from Cerralvo, northeastern Mexico. Palaeontology 47: 1575 - 1627.","Ifrim, C., W. Stinnesbeck, and A. Schafhauser. 2005. Maastrichtian shallow-water ammonites of northeastern Mexico. Revista Mexicana de Ciencias Geologicas 22: 48 - 64.","Weller, S. 1907. A report on the Cretaceous paleontology of New Jersey. Geological Survey of New Jersey. Paleontology Series 4: 1 - 870.","Reeside, J. B., Jr. 1962. Cretaceous ammonites of New Jersey. In H. G. Richards (editor), The Cretaceous fossils of New Jersey. New Jersey Department of Conservation and Economic Development Bulletin 61, Part 2: 113 - 137.","Gallagher, W. B. 1993. The Cretaceous / Tertiary mass extinction event in the northern Atlantic coastal plain. Mosasaur 5: 75 - 155.","Landman, N. H., R. O. Johnson, and L. E. Edwards. 2004 a. Cephalopods from the Cretaceous / Tertiary boundary interval on the Atlantic coastal plain, with a description of the highest ammonite zones in North America. Part 1, Maryland and North Carolina. American Museum Novitates 3454: 1 - 64.","Landman, N. H., R. O. Johnson, and L. E. Edwards. 2004 b. Cephalopods from the Cretaceous / Tertiary boundary interval on the Atlantic coastal plain, with a description of the highest ammonite zones in North America. Part 2, Northeastern Monmouth County, New Jersey. Bulletin of the American Museum of Natural History 287: 1 - 107.","Ifrim, C., and W. Stinnesbeck. 2010. Migration pathways of the late Campanian and Maastrichtian shallow facies ammonite Sphenodiscus in North America. Palaeogeography, Palaeoclimatology, Palaeoecology 292: 96 - 102.","Landman, N. H., S. Goolaerts, J. W. M. Jagt, E. A. Jagt-Yazykova, and M. Machalski. 2015. Ammonites on the brink of extinction: diversity, abundance, and ecology of the order Ammonoidea at the Cretaceous / Paleogene (K / Pg) Boundary. In C. Klug, D. Korn, K. De Baets, I. Kruta, and R. H. Mapes (editors), Ammonoid paleobiology: from macroevolution to paleogeography: 497 - 553. Dordrecht: Springer.","Larina, E., et al. 2016. Upper Maastrichtian ammonite biostratigraphy of the Gulf Coastal Plain (Mississippi Embayment, southern USA). Cretaceous Research 60: 128 - 151."]}

Genus Sphenodiscus Meek, 1871 TYPE SPECIES: Ammonites lenticularis Owen, 1852: 579 (non Young and Bird, 1828: 269, fig. 5), by original designation, = Ammonites lobata Tuomey, 1856: 168., Published as part of Witts, James D., Landman, Neil H., Garb, Matthew P., Irizarry, Kayla M., Larina, Ekaterina, Thibault, Nicolas, Razmjooei, Mohammad J., Yancey, Thomas E. & Myers, Corinne E., 2021, Cephalopods from the Cretaceous-Paleogene (K-Pg) boundary interval on the Brazos River, Texas, and extinction of the ammonites, pp. 1-52 in American Museum Novitates 2021 (3964) on page 21, DOI: 10.1206/3964.1, http://zenodo.org/record/4566589, {"references":["Meek, F. B. 1871. Preliminary paleontological report, consisting of lists of fossils, with descriptions of some new types etc. Preliminary Report of the United States Geological Survey of Wyoming and portions of contiguous territories 4: 287 - 318.","Owen, D. D. 1852. Report of a geological survey of Wisconsin, Iowa, and Minnesota and incidentally of a portion of Nebraska Territory. Philadelphia: Lippincott.","Young, G., and J. Bird. 1828. A geological survey of the Yorkshire coast: describing the strata and fossils occurring between the Humber and the Tees, from the German ocean to the plain of York. 2 nd ed. Whitby, England: R. Kirby.","Tuomey, M. 1856. Description of some new fossils from the Cretaceous rocks of the southern States. Proceedings of the Academy of Natural Sciences of Philadelphia 7: 167 - 172."]}

Gaudryceras sp. Figure 8 MATERIAL: One small specimen AMNH 111956 from the Corsicana Formation 1 m below the K-Pg boundary at AMNH loc. 3620 (Darting Minnow Creek). DESCRIPTION: Diameter of the specimen is 15.6 mm. It is entirely septate and mostly covered with shell (fig. 2F), with a tiny bit of suture exposed. It is serpenticonic with UD = 8.9 mm. The rate of whorl expansion is low. The ornament consists of thin lirae that are convex on the umbilical wall and shoulder and straight and prorsiradiate on the middle and outer flanks. They cross the venter with a slight adoral projection. REMARKS: Because of the small size of this specimen, it is impossible to identify it to the species level (R. Hoffmann and Y. Shigeta, personal commun., 2019). However, it is the only specimen of Gaudryceras ever found at Brazos and one of only a handful of lytoceratid ammonite specimens described from the Maastrichtian of North America (Cobban and Kennedy, 1995; Kennedy et al., 2000). OCCURRENCE: Gaudryceras is worldwide in its distribution and is reported from the Maastrichtian of Tunisia, Zululand, and Pondoland, South Africa (Klinger and Kennedy, 1979), Madagascar, south India, Japan, western Australia, California, Chile, and the Antarctic Peninsula. The closest occurrences of this genus to the Brazos River locality are in the lower Campanian of Travis County, Texas (Young, 1963), the lower upper Maastrichtian Corsicana Formation near San Antonio, Bexar County, Texas (Woehr, 2013), the upper Campanian Saratoga Chalk of Arkansas (Kennedy and Cobban, 1993b), and the Maastrichtian Méndez Formation of northeastern Mexico (Ifrim et al., 2004)., Published as part of Witts, James D., Landman, Neil H., Garb, Matthew P., Irizarry, Kayla M., Larina, Ekaterina, Thibault, Nicolas, Razmjooei, Mohammad J., Yancey, Thomas E. & Myers, Corinne E., 2021, Cephalopods from the Cretaceous-Paleogene (K-Pg) boundary interval on the Brazos River, Texas, and extinction of the ammonites, pp. 1-52 in American Museum Novitates 2021 (3964) on page 20, DOI: 10.1206/3964.1, http://zenodo.org/record/4566589, {"references":["Cobban, W. A., and Kennedy, W. J. 1995. Maastrichtian ammonites chiefly from the Prairie Bluff Chalk in Alabama and Mississippi. Memoir, the Paleontological Society 44: 1 - 40.","Kennedy, W. J., and H. C. Klinger 1979. Cretaceous faunas from Zululand and Natal, South Africa. The ammonite family Gaudryceratidae. Bulletin of the British Museum of Natural History (Geology) 31: 121 - 174.","Young, K. 1963. Upper Cretaceous ammonites from the Gulf Coast of the United States. University of Texas Bulletin 6304. 373 pp.","Woehr, D. A. 2013. Die Fauna der Corsicana-Formation (Maastrichtium) von Texas. Der Steinkern 14: 44 - 67.","Kennedy, W. J., and W. A. Cobban. 1993 b. Ammonites from the Saratoga Chalk (Upper Cretaceous), Arkansas. Journal of Paleontology 67: 404 - 434.","Ifrim, C., W. Stinnesbeck, and J. G. Lopez-Oliva. 2004. Maastrichtian cephalopods from Cerralvo, northeastern Mexico. Palaeontology 47: 1575 - 1627."]}

Sphenodiscus lobatus (Tuomey, 1856) Figure 9A Ammonites lenticularis Owen, 1852: 579, pl. 8, fig. 5. Ammonites lobatus Tuomey, 1856: 168. Sphenodiscus pleurisepta (Tuomey, 1854). Cobban and Kennedy, 1995: 61, fig. 3a, v. Sphenodiscus lobatus (Tuomey, 1856). Cobban and Kennedy, 1995: 12, figs. 6.2, 6.3, 8.4, 8.6– 8.11, 12.18, 12.19, 16.16, 16.17 (with full synonymy). Sphenodiscus lobatus (Tuomey, 1856). Kennedy and Cobban, 1996: 802, fig. 2.4–2.6, 2.13, 2.14, 2.19, 2.21. Sphenodiscus lobatus (Tuomey, 1856). Kennedy et al., 1997: 4, figs. 3–8, 9A–I, 10. Sphenodiscus lobatus (Tuomey, 1856). Landman et al., 2004a: 28, fig. 12. Sphenodiscus lobatus (Tuomey, 1856). Landman et al., 2004b: 51, figs. 23–25. Sphenodiscus lobatus (Tuomey, 1856). Landman et al., 2007a: 58, figs. 26–28. TYPE: The holotype, from Noxubee County, Mississippi, is lost (fide Stephenson, 1941: 434). MATERIAL: Three fragments AMNH 112039, 112070, and 112085, all from the upper 1 m of the Corsicana Formation just below the K-Pg boundary, and one fragment AMNH 135054 from the basal unit (mudstone-clast-bearing conglomerate) of the K-Pg event deposit itself. DESCRIPTION: AMNH 112070 is a fragment of a phragmocone, AMNH 112085 is a fragment of the outer flanks of a body chamber, and AMNH 135054 is a single small chamber with part of the septum. All show the characteristic smooth flanks indicative of this species. REMARKS: In contrast to the preservation of whole scaphites and baculitids, all the specimens of Sphenodiscus lobatus in our collection are fragmentary. This suggests that perhaps the shells floated into the area after death and may have lived closer to shore, which is consistent with isotopic evidence from shell samples of this species from the age-equivalent Owl Creek Formation in Mississippi (Sessa et al., 2015). OCCURRENCE: The few fragments are from the top 1 m of the Corsicana Formation (AMNH loc. 3620 and AMNH loc. 3621) and the basal unit of the overlying K-Pg event deposit at AMNH loc. 3620. Sphenodiscus lobatus has also been reported from the Corsicana Formation in Navarro County, Texas (Kennedy and Cobban, 1993a; see also Stephenson, 1941, 1955). It occurs in the Escondido Formation in Texas (Böse, 1928) and northern Mexico. Elsewhere in Mexico, it occurs in the Maastrichtian Cerro del Pueblo Formation of the Difunta Group at Rincón Colorado, Coahuila (Ifrim et al., 2004, 2005). On the eastern Gulf Coastal Plain, it occurs in the upper part of the Ripley Formation in Mississippi and the Prairie Bluff Chalk in Alabama and Mississippi (Cobban and Kennedy, 1995). On the Atlantic Coastal Plain, it occurs in the top of the Tinton Formation, the upper part of the Navesink Formation, the lower part of the New Egypt Formation, and as reworked material at the base of the Hornerstown Formation in Monmouth County (Weller, 1907; Reeside, 1962; Gallagher, 1993; Landman et al., 2004a, 2007a) and in the upper part of the Navesink Formation in Gloucester County, New Jersey (Gallagher, 1993; Kennedy et al., 1995; Kennedy and Cobban, 1996); in the Providence Sand in the Chattahoochee River area, Alabama and Georgia; in the upper part of the Peedee Formation in North Carolina (Landman et al., 2004a); and in the Severn Formation in Prince Georges County, Maryland (Kennedy et al., 1997). In the Western Interior, this species occurs in the Hoploscaphites nicolletii and H. nebrascensis Zones of the Fox Hills Formation in north-central South Dakota (Landman and Waage, 1993) and in the H. nebrascensis Zone of the Pierre Shale in southeastern South Dakota and northeastern Nebraska (Kennedy et al., 1998)., Published as part of Witts, James D., Landman, Neil H., Garb, Matthew P., Irizarry, Kayla M., Larina, Ekaterina, Thibault, Nicolas, Razmjooei, Mohammad J., Yancey, Thomas E. & Myers, Corinne E., 2021, Cephalopods from the Cretaceous-Paleogene (K-Pg) boundary interval on the Brazos River, Texas, and extinction of the ammonites, pp. 1-52 in American Museum Novitates 2021 (3964) on page 22, DOI: 10.1206/3964.1, http://zenodo.org/record/4566589, {"references":["Tuomey, M. 1856. Description of some new fossils from the Cretaceous rocks of the southern States. Proceedings of the Academy of Natural Sciences of Philadelphia 7: 167 - 172.","Owen, D. D. 1852. Report of a geological survey of Wisconsin, Iowa, and Minnesota and incidentally of a portion of Nebraska Territory. Philadelphia: Lippincott.","Cobban, W. A., and Kennedy, W. J. 1995. Maastrichtian ammonites chiefly from the Prairie Bluff Chalk in Alabama and Mississippi. Memoir, the Paleontological Society 44: 1 - 40.","Kennedy, W. J., and W. A. Cobban. 1996. Maastrichtian ammonites from the Hornerstown Formation in New Jersey. Journal of Paleontology 70: 798 - 804.","Kennedy, W. J., W. A. Cobban, and N. H. Landman. 1997. Maastrichtian ammonites from the Severn Formation of Maryland. American Museum Novitates 3210: 1 - 30.","Landman, N. H., R. O. Johnson, and L. E. Edwards. 2004 a. Cephalopods from the Cretaceous / Tertiary boundary interval on the Atlantic coastal plain, with a description of the highest ammonite zones in North America. Part 1, Maryland and North Carolina. American Museum Novitates 3454: 1 - 64.","Landman, N. H., R. O. Johnson, and L. E. Edwards. 2004 b. Cephalopods from the Cretaceous / Tertiary boundary interval on the Atlantic coastal plain, with a description of the highest ammonite zones in North America. Part 2, Northeastern Monmouth County, New Jersey. Bulletin of the American Museum of Natural History 287: 1 - 107.","Landman, N. H., R. O. Johnson, M. P. Garb, L. E. Edwards, and F. T. Kyte. 2007 a. Cephalopods from the Cretaceous / Tertiary boundary interval on the Atlantic coastal plain, with a description of the highest ammonite zones in North America. Part 3, Manasquan River Basin, Monmouth County, New Jersey. Bulletin of the American Museum of Natural History 303: 1 - 122.","Stephenson, L. W. 1941. The larger invertebrate fossils of the Navarro Group of Texas (exclusive of corals and crustaceans and exclusive of the fauna of the Escondido Formation). University of Texas Bulletin 4101: 1 - 641.","Sessa, J. A., et al. 2015. Ammonite habitat revealed via isotopic composition and comparisons with cooccurring benthic and planktonic organisms. Proceedings of the National Academy of Sciences of the United States of America 112: 15562 - 15567.","Kennedy, W. J., and W. A. Cobban. 1993 a. Maastrichtian ammonites from the Corsicana Formation in northeast Texas. Geological Magazine 130: 57 - 67.","Stephenson, L. W. 1955. Owl Creek (Upper Cretaceous) fossils from Crowley's Ridge, southeastern Missouri. United States Geological Survey Professional Paper 274: 97 - 140","Bose, E. 1928. Cretaceous ammonites from Texas and northern Mexico. Bulletin of the University of Texas, Bureau of Economic Geology and Technology, Austin 2748, 143 - 312.","Ifrim, C., W. Stinnesbeck, and J. G. Lopez-Oliva. 2004. Maastrichtian cephalopods from Cerralvo, northeastern Mexico. Palaeontology 47: 1575 - 1627.","Ifrim, C., W. Stinnesbeck, and A. Schafhauser. 2005. Maastrichtian shallow-water ammonites of northeastern Mexico. Revista Mexicana de Ciencias Geologicas 22: 48 - 64.","Weller, S. 1907. A report on the Cretaceous paleontology of New Jersey. Geological Survey of New Jersey. Paleontology Series 4: 1 - 870.","Reeside, J. B., Jr. 1962. Cretaceous ammonites of New Jersey. In H. G. Richards (editor), The Cretaceous fossils of New Jersey. New Jersey Department of Conservation and Economic Development Bulletin 61, Part 2: 113 - 137.","Gallagher, W. B. 1993. The Cretaceous / Tertiary mass extinction event in the northern Atlantic coastal plain. Mosasaur 5: 75 - 155.","Kennedy, W. J., R. O. Johnson, and W. A. Cobban. 1995. Upper Cretaceous ammonite faunas of New Jersey. In J. E. B. Baker (editor), Contributions to the paleontology of New Jersey 12: 24 - 55.","Landman, N. H., and K. M. Waage. 1993. Scaphitid ammonites of the Upper Cretaceous (Maastrichtian) Fox Hills Formation in South Dakota and Wyoming. Bulletin of the American Museum of Natural History 215: 1 - 257.","Kennedy, W. J., N. H. Landman, W. K. Christensen, W. A. Cobban, and J. M. Hancock. 1998. Marine connections in North America during the late Maastrichtian: palaeogeographic and palaeobiogeographic significance of Jeletzkytes nebrascensis Zone cephalopod fauna from the Elk Butte Member of the Pierre Shale, SE South Dakota and NE Nebraska. Cretaceous Research 19: 745 - 775."]}

In The Politics of Counsel in England and Scotland (2016), Jacqueline Rose argues that studying early modern political counsel poses problems of evidence, for official sources and chronicles tend to “record decisions, not discussions”. In fact, chroniclers only partially show the debates which precede royal decisions. Meanwhile, late Elizabethan history plays increasingly focus on counsel on stage and thoroughly explore its discursive aspects. In so doing, they allow the audience to attend a representation of counsel in the making, thus subjecting the mechanisms of persuasion and deliberation to sharp scrutiny. This is particularly striking in plays which focus on young kings, as I shall argue: for the latter strongly rely on advice and are more likely to place trust in the wrong counselors. I have therefore chosen four plays which offer variations on the figure of the young sovereign and take us behind the scenes of deliberation: The Life and Death of Jack Straw (c. 1590-93), Shakespeare’s Henry VI I and II (c. 1591-92) and Thomas of Woodstock (c. 1591-95). These plays all somehow suggest that royal decisions even when founded on counsel are not taken for granted as royal authority comes to be questioned. In theory, deliberation consisted in the rational exploration of different options, ending with a logical and uncontested conclusion. If Jack Straw seems faithful to such an ideal conception of power, the three other plays are much more skeptical. In these plays, counsel is consistently staged as a practical problem, a highly rhetorical moment that can be subverted, making it harder for young kings to discriminate between good and bad advice. The manipulation of reasoning in turn highlights the precariousness of counsel and points to the potential arbitrariness in decision-making. The final decision, far from being the only definitive conclusion, seems arbitrary, as just one choice among many possibilities. So I’d like to show how these history plays, by recreating “conciliar performances”, reveal how uncertain and contingent the art of political deliberation may be.

In early modern England, counsel was a “ubiquitous and inescapable element of life” (Jacqueline Rose, 2016) and the 1590s saw a resurgence of counsel on stage, particularly in history plays. If it was then difficult to debate topical issues and give specific advice to the sovereign through plays written for a popular audience, some playwrights chose for example to engage popular audiences into appropriating the idea of counsel. This could happen by presenting the voices of those not actively or directly involved in governance in the space of political discussion, sharing it temporarily with more courtly or authorized ones – thus suggesting that the common good was the affair of all citizens. By presenting a wide range of advising characters instead of a typical figure of the counsellor, these plays turned counsel into a mask anyone – and not only courtiers – could try and wear, even for a brief moment. In this paper, I will focus on one of these plays, The First Part of King Edward IV, by Thomas Heywood (c. 1599), which is set in times of crisis (both popular revolt and dynastic uncertainty) and builds on that context to present an unusual adviser: Hobs, the Tanner of Tamsworth. I would like to show that, by playing on the tension between private and public, the play questions the possibility and the visibility of popular counsel.

Si les références aux machines se multiplient au XVIe siècle pour décrire l’univers réglé par Dieu ou encore le corps humain (l’organique étant conçu comme une mécanique), elles se font plus rares lorsqu’il s’agit d’aborder la question politique. Revient cependant, pour désigner le commonwealth, l’image du corps humain dont l’harmonie entre les différents membres, au sein d’une stricte hiérarchie, est la condition sine qua non de la bonne marche du royaume. Mais là où les traités théoriques et les discours officiels (sermons, homélies, …) dessinent un idéal parfaitement ordonné, le théâtre historique de la fin du XVIe et du début du XVIIe siècles en propose une vision bien plus nuancée, faite de dérèglements et de machinations. En donnant notamment une place de plus en plus importante aux figures de conseillers, qui obligent le roi à partager la scène – du théâtre mais aussi du pouvoir –, ces pièces dévoilent les coulisses de la pratique politique à un public qui en est le plus souvent, et pour la plupart de ses membres, exclu. La politique y apparaît comme la sphère de l’imprévu et de l’incertitude, marquée par la possibilité de l’erreur – autant celle du roi que de ses conseillers – et donc par la délibération à plusieurs et pas uniquement par la décision ou l’action d’un seul homme. La politique commande alors de s’adapter à son temps, principe machiavélien par excellence, là où l’expertise est difficilement mesurable et la légitimité – pour les conseillers, du moins – souvent contestable. Il s’agit donc de s’interroger à la fois sur le politique comme machine potentiellement infernale et sur l’identité de ceux choisis – par le roi – pour la manipuler. À une époque où, suite aux progrès techniques et scientifiques, émerge une classe technocratique dans de nombreux domaines comme la navigation (le pilote cédant sa place à l’expert), la politique n’a pas encore le statut d’une science ni d’une technique.

The early Eocene (c. 56 - 48 million years ago) experienced some of the highest global temperatures in Earth’s history since the Mesozoic, with no polar ice. Reports of contradictory ice-rafted erratics and cold water glendonites in the higher latitudes have been largely dismissed due to ambiguity of the significance of these purported cold-climate indicators. Here we apply clumped isotope paleothermometry to a traditionally qualitative abiotic proxy, glendonite calcite, to generate quantitative temperature estimates for northern mid-latitude bottom waters. Our data show that the glendonites of the Danish Basin formed in waters below 5 °C, at water depths of, The early Eocene was characterized by exceptionally high global temperatures and no polar ice. Here, clumped isotope paleothermometry of glendonite calcite from the Danish Basin shows that these were formed in waters below 5 °C, indicating that regionalised cool episodes punctuated the background warmth of the early Eocene.

Clumped isotope based temperature estimates from exceptionally well-preserved belemnites from Staffin Bay (Isle of Skye, Scotland) reveal that seawater temperatures throughout the Middle-Late Jurassic were significantly warmer than previously reconstructed by conventional oxygen isotope thermometry. We demonstrate here that this underestimation by oxygen isotope thermometry was likely due to a) using the incorrect calcite thermometry equation for belemnite temperature reconstructions and b) by incorrectly estimating the seawater δ 18 O ( δ 18 O sw ) for the Hebrides Basin. Our data suggests that the fractionation factor for oxygen isotopes in belemnites from seawater was closer to that of slow-growing abiogenic calcites than that of other marine calcifying organisms. Our clumped isotope temperatures are used to reconstruct δ 18 O sw trends across the Callovian–Kimmeridgian in the Hebrides Basin. The δ 18 O sw varied significantly in the Hebrides Basin throughout this interval, possibly as a result of changing currents through the Laurasian seaway. Trends in temperature and δ 18 O sw are compared to published palaeoceanographic studies to shed light on changing palaeoceanography in the Tethyan and Boreal realms throughout the Middle–Late Jurassic.

Understanding the end-Triassic mass extinction event (201.36 Ma) requires a clear insight into the stratigraphy of boundary sections, which allows for long-distance correlations and correct distinction of the sequence of events. However, even after the ratification of a Global Stratotype Section and Point, global correlations of TJB successions are hampered by the fact that many of the traditionally used fossil groups were severely affected by the crisis. Here, a new correlation of key TJB successions in Europe, U.S.A. and Peru, based on a combination of biotic (palynology and ammonites), geochemical (δ 13 C org ) and radiometric (U/Pb ages) constraints, is presented. This new correlation has an impact on the causality and temporal development during the end-Triassic event. It challenges the hitherto used standard correlation, which has formed the basis for a hypothesis that the extinction was caused by more or less instantaneous release of large quantities of light carbon (methane) to the atmosphere, with catastrophic global warming as a consequence. The new correlation instead advocates a more prolonged scenario with a series of feedback mechanisms, as it indicates that the bulk of the hitherto dated, high-titanium, quartz normalized volcanism of the Central Atlantic Magmatic Province (CAMP) preceded or was contemporaneous to the onset of the mass extinction. In addition, the maximum phase of the mass extinction, which affected both the terrestrial and marine ecosystems, was associated with a major regression and repeated, enhanced earthquake activity in Europe. A subsequent transgression resulted in the formation of hiati or condensed successions in many areas in Europe. Later phases of volcanic activity of the CAMP, producing low titanium, quartz normalized and high-iron, quartz normalized basaltic rocks, continued close to the first occurrence of Jurassic ammonites and the defined TJB. During this time the terrestrial ecosystem had begun to recover, but the marine ecosystem remained disturbed.

The Middle Ordovician (∼460-470 Ma) in Baltoscandia is mainly represented by the so called ‘orthoceratite lime-stone’. This is a geographically wide-spread condensed sedimentary succession of a few tens of meters thicknessconsisting of fine-grained limestones deposited at middle paleolatitudes. These successions have a long history ofdetailed litho- and biostratigraphical research, which in recent years is complemented with chemostratigraphicalinvestigations (mainly stable carbon isotopes). New mm-resolution XRF elemental core scanning data from theTingskullen-1 and Kårehamn P4 cores from the island of Öland, Sweden, reveal the potential to further test thehypothesis of the presence of Milankovitch scale cyclicity in these records. This new high-resolution data alsoresolves the regular occurrence of hardgrounds in this ‘orthoceratite limestone’, as for example expressed in min-ima in carbonate content and peaks in detrital elements. These dissolution surfaces have been suggested to berelated to carbonate production-dissolution alternations. It is interesting that many of the relative changes in theelemental profiles seem to be related to these dissolution horizons and show a certain regularity in occurrence ondifferent spatial levels. The ratio between the different periods, in combination with specific patterns of amplitudemodulation - both visually and statistically inspected - suggests the presence of a precessional scale variability,bundled in eccentricity cycles. Besides the existing integrated stratigraphical framework, these interpretations canbe tested by ongoing geochronological work (CA-TIMS U-Pb dating of zircons from volcanic ash layers present inthese successions). The prospective of building an astronomical timescale for the Middle Ordovician can shed newlight on its climate dynamics and associated tempo and duration of important events such as the Great OrdovicianBiodiversification Event (GOBE) and the middle Darriwilian carbon isotope excursion (MDICE).

Cyclostratigraphy is an important tool for understanding astronomical climate forcing and reading geological time in sedimentary sequences, provided that an imprint of insolation variations caused by Earth's orbital eccentricity, obliquity and/or precession is preserved (Milankovitch forcing). Numerous stratigraphic and paleoclimate studies have applied cyclostratigraphy, but the robustness of the methodology and its dependence on the investigator have not been systematically evaluated. We developed the Cyclostratigraphy Intercomparison Project (CIP) to assess the robustness of cyclostratigraphic methods using an experimental design of three artificial cyclostratigraphic case studies with known input parameters. Each case study is designed to address specific challenges that are relevant to cyclostratigraphy. Case 1 represents an offshore research vessel environment, as only a drill-core photo and the approximate position of a late Miocene stage boundary are available for analysis. In Case 2, the Pleistocene proxy record displays clear nonlinear cyclical patterns and the interpretation is complicated by the presence of a hiatus. Case 3 represents a Late Devonian proxy record with a low signal-to-noise ratio with no specific theoretical astronomical solution available for this age. Each case was analyzed by a test group of 17-20 participants, with varying experience levels, methodological preferences and dedicated analysis time. During the CIP 2018 meeting in Brussels, Belgium, the ensuing analyses and discussion demonstrated that most participants did not arrive at a perfect solution, which may be partly explained by the limited amount of time spent on the exercises (∼4.5 hours per case). However, in all three cases, the median solution of all submitted analyses accurately approached the correct result and several participants obtained the exact correct answers. Interestingly, systematically better performances were obtained for cases that represented the data type and stratigraphic age that were closest to the individual participants’ experience. This experiment demonstrates that cyclostratigraphy is a powerful tool for deciphering time in sedimentary successions and, importantly, that it is a trainable skill. Finally, we emphasize the importance of an integrated stratigraphic approach and provide flexible guidelines on what good practices in cyclostratigraphy should include. Our case studies provide valuable insight into current common practices in cyclostratigraphy, their potential merits and pitfalls. Our work does not provide a quantitative measure of reliability and uncertainty of cyclostratigraphy, but rather constitutes a starting point for further discussions on how to move the maturing field of cyclostratigraphy forward. © 2019 The Authors, The Cyclostratigraphy Intercomparison Project (CIP) and Workshop are supported by the Royal Flemish Academy of Belgium for Science and the Arts (KVAB) , Research Foundation – Flanders (FWO) , Fund for Scientific Research (FNRS) , International Association of Sedimentology (IAS) , Earthrates (National Science Foundation) and the Vrije Universiteit Brussel (VUB) – Hooverfonds . Matthias Sinnesael thanks the Research Foundation of Flanders (FWO) for the awarded PhD Fellowship (FWOTM782).

The Campanian age (Late Cretaceous) is generally considered as a period of globally ice-free, warm greenhouse climate (Huber et al., 2002). Understanding controls and modes of Earth’s climate change in such a greenhouse world is essential for predictions of future climate change due to anthropogenic greenhouse gas emissions. Most of the literature on Late Cretaceous climate changes focuses on reconstructing the evolution of humid/arid conditions on land and/or past atmospheric and oceanic temperatures. Assessing the extent of seasonal change has seldom been studied so far, although such data constitute a fundamental component of the climate system. Fossil bivalve shells offer a valuable record for studying past climates at a seasonal scale. The chemistry of bivalve shells can record information about the environment in which bivalves grew, and incremental measurements of chemical changes in growth direction have the potential to yield records of seasonal changes in this environment. Examples of chemical proxies used for these palaeoseasonality reconstructions are stable carbon and oxygen isotopes and trace element ratios (e.g. de Winter et al., 2017). However, many open questions still exist regarding the incorporation of these chemical proxies into bivalve shells. Many of these challenges arise from the influence of so-called vital effects on the chemistry of precipitated carbonate in the shells (Weiner and Dove, 2003). In modern bivalves, these vital effects have been shown to interfere with characteristic relationships between shell chemistry and the environment and these vital effects appear to be distinct not only between different bivalve species but also between specimens of different ontogenetic age (Freitas et al., 2008). In this study, an attempt is made to isolate the effects of environmental change from vital effects recorded in stable isotope and trace element records from fossil bivalves. This is achieved by comparing results from different species and different individuals of the same species in the same palaeoenvironmental setting. The Early Campanian Kristianstad Basin localities used in this study offer abundant bivalve fossils from various taxa (Sørensen et al., 2015). Comparing multi-proxy records both within and between species sheds light on the influence of species-specific and age-specific effects on the expression of seasonal variations in shell chemistry. It also allows disentangling vital effects from environmental influences in an effort to improve palaeoseasonality reconstructions in the Late Cretaceous greenhouse. de Winter et al. (2017). Tropical seasonality in the late Campanian (late Cretaceous): Comparison between multiproxy records from three bivalve taxa from Oman. Palaeogeography, Palaeoclimatology, Palaeoecology, 485, 740-760. Freitas et al. (2008). Inter-and intra-specimen variability masks reliable temperature control on shell Mg/Ca ratios in laboratory and field cultured Mytilus edulis and Pecten maximus (bivalvia). Biogeosciences Discussions, 5(1), 531-572. Huber et al. (2002). Deep-sea paleotemperature record of extreme warmth during the Cretaceous. Geology, 30(2), 123-126. Sørensen et al. (2015). Geochemical signatures of the early Campanian belemnite Belemnellocamax mammillatus from the Kristianstad Basin in Scania, Sweden. Palaeo3 433, 191-200. Weiner & Dove (2003). An overview of biomineralization processes and the problem of the vital effect. Reviews in mineralogy and geochemistry, 54(1), 1-29.

International audience; Diachronism is a well-known issue in stratigraphy. In the case of various macro-and microfossil groups,several statistical methods such as constrained optimization (CONOP) or unitary associations have beenproposed to remedy such issues and improve the Geologic Time Scale. The purpose of the latter methods is toexamine misfits, eliminate problematic bio-events in favor of the most reliable biostratigraphic markers and todraw the best statistical or optimal biostratigraphic series. Such methods do not attempt, however, to quantifydiachronism nor to understand its possible causes besides issues linked to preservation, inadequate samplingor incorrect dating. The integration of numerous stratigraphic techniques (chemostratigraphy,magnetostratigraphy, high-precision radiometric dating and cyclostratigraphy) allows today a much bettercharacterization of potential diachronism in some of the key stratigraphic macro-and microfossil marinegroups. Here, we will examine case-studies from the Mesozoic where well-demonstrated examples ofdiachronism call for a modification of some of the “standard” marine microfossil zones but also tracepaleoenvironmental change. Rather than to be considered as a pitfall, more emphasis should be put on potentialdiachronism as it can improve both stratigraphy and our understanding of ocean currents, climate, continentconfiguration and/or sea-level change.

National audience; Nous proposons un algorithme simple pour la mise à jour d'un arbre couvrant un groupe dont les membres peuvent arriver et/ou partir à chaque étape. L'objectif est alors de maintenir un arbre dont le diamètre est proche du diamètre minimum. La dynamicité des membres et le respect de la contrainte sur le diamètre peuvent nécessiter la reconstruction de l'arbre. Une étape de reconstruction étant coÛteuse, nous nous intéressons à la minimisation de ce nombre d'étapes. Si cette démarche a déjà été étudiée, les précédents travaux se sont restreints à l'étude du pire cas (algorithmes d'approximation ou étude du rapport de compétitivité dans le contexte online). Dans cet article, nous analysons le comportement de notre algorithme en moyenne. Pour cela, nous proposons quelques encadrements analytiques particuliers et un moyen algorithmique efficace pour calculer de manière exacte l'espérance du nombre de reconstructions (sous des hypothèses d'équiprobabilité). Nous donnons alors les grandes tendances de cette espérance.

National audience; Cet article est consacré au problème de l'interconnexion de plusieurs groupes dans un réseau. Nous cherchons ici á réserver des ressources (liens de communication) du réseau, afin d'établir des connexions efficaces entre les membres de chaque groupe. Ces connexions doivent fournir des garanties sur la latence maximum (ou temps de communication maximum) de chaque groupe dans la ou les structures formées par les ressources réservées. Nous allons montrer que les approches pour interconnecter des groupes qui conservent les diamètres donnent lieu á des problèmes algorithmiques difficiles. Ces résultats nous conduisent á proposer une autre approche consistant á construire un seul arbre pour interconnecter tous les groupes. Nous proposons ici le premier algorithme avec garantie de performance mettant en oeuvre cette approche.

Resource reservation in a communication network is a research area leading to many algorithmic problems. A network can be seen as a graph, in order to easily design algorithms for resource reservation. The purpose is to manage as well as possible the resonrces for members who want to communicate using the network. For resource reservation in a single link, we use scheduling algorithms. In these problems, we can not always know al1 the informations about the problem since the beginning. To consider this lack of information, we consider the on-line setting. The informations are revealed one by one, without any knowledge of the future. For each problem we treat, we propose algorithms with an analytical evaluation, considering one (resp. several) performance criterion (resp. criteria).; La réservation de ressources dans un réseau de communication est un domaine d'application très vaste, qui implique des problèmes algorithmiques nombreux et variés. La modélisation d'un réseau sous la forme d'un graphe permet, indépendamment de sa nature physique, de développer des algorithmes pour déterminer quels sont les noeuds et/ou les liens du réseau qui doivent être réservés. Il s'agit de gérer au mieux l'attribution de ces ressources pour les membres qui inter-agissent via le réseau. Pour la résolution de problèmes liés à la réservation de ressources au niveau d'un lien particulier, c'est la modélisation sous la forme d'un ordonnancement qui est alors particulièrement adaptée. Dans ce type de problèmes, il n'est pas toujours possible de connaître à l'avance toutes les données à traiter. En effet, les demandes de membres amenés à communiquer via le réseau ainsi que les demandes de réservation au niveau des liens arrivent en pratique au fils de l'eau. Pour prendre en compte cette difficulté, nous nous plaçons dans le contexte de l'algorithmique on-line (en ligne). Les données du problème à traiter ne sont donc pas connues dès le départ, mais révélées au fur et à mesure, sans aucune connaissance du futur. Pour chacun des problèmes on-lines traités, nous proposons des algorithmes que nous évaluons analytiquement, en fonction d'un (ou parfois plusieurs) critère(s) de performance.

National audience; Cet article est consacré au problème suivant : étant donné un ensemble de membres dans un réseau, construire une structure permettant de les connecter tout en minimisant le poids de la structure, ainsi que la distance moyenne et maximale entre membres. Nous traitons ici plus spécifiquement l'aspect dynamique du problème lié au fait que de nouveaux membres peuvent intégrer la structure et d'autres la quitter. Nous prenons en compte le fait que les membres à connecter et les membres à déconnecter ne sont pas connus dès le début, mais dévoilés au fur et à mesure. Après avoir modélisé cette situation sous forme de problème de graphe, nous faisons une synthèse de nos travaux concernant différentes méthodes (de type online) qui seront classées en deux grandes catégories : les méthodes sans reconstruction (un ajout se fait par incrémentation et un retrait par décrémentation de la structure courante) et les méthodes avec reconstructions (on s'autorise à casser des liens internes de la structure courante pour traiter un ajout ou un retrait).

National audience

International audience; Given a weighted graph G=(V,E,w), we investigate the problem of constructing a sequence of n=|V| subsets of vertices M_1,...,M_n (called groups) with small diameters, where the diameter of a group is calculated using distances in G. The constraint on these n groups is that they must be incremental: $M_1\subsetM_2 \subset...\subsetM_n=V$. The cost of a sequence is the maximum ratio between the diameter of each group $M_i$ and the diameter of a group $N_i^*$ with $i$ vertices and minimum diameter: $\max_2 \leqi \leqn \left \fracD(M_i)D(N_i^*) \right$. This quantity captures the impact of the incremental constraint on the diameters of the groups in a sequence. We give general bounds on the value of this ratio and we prove that the problem of constructing an optimal incremental sequence cannot be solved approximately in polynomial time with an approximation ratio less than 2 unless $P = NP$. Finally, we give a 4-approximation algorithm and we show that the analysis of our algorithm is tight.

Resource reservation in a communication network is a research area leading to many algorithmic problems. A network can be seen as a graph, in order to easily design algorithms for resource reservation. The purpose is to manage as well as possible the resonrces for members who want to communicate using the network. For resource reservation in a single link, we use scheduling algorithms. In these problems, we can not always know al1 the informations about the problem since the beginning. To consider this lack of information, we consider the on-line setting. The informations are revealed one by one, without any knowledge of the future. For each problem we treat, we propose algorithms with an analytical evaluation, considering one (resp. several) performance criterion (resp. criteria)., La réservation de ressources dans un réseau de communication est un domaine d'application très vaste, qui implique des problèmes algorithmiques nombreux et variés. La modélisation d'un réseau sous la forme d'un graphe permet, indépendamment de sa nature physique, de développer des algorithmes pour déterminer quels sont les noeuds et/ou les liens du réseau qui doivent être réservés. Il s'agit de gérer au mieux l'attribution de ces ressources pour les membres qui inter-agissent via le réseau. Pour la résolution de problèmes liés à la réservation de ressources au niveau d'un lien particulier, c'est la modélisation sous la forme d'un ordonnancement qui est alors particulièrement adaptée. Dans ce type de problèmes, il n'est pas toujours possible de connaître à l'avance toutes les données à traiter. En effet, les demandes de membres amenés à communiquer via le réseau ainsi que les demandes de réservation au niveau des liens arrivent en pratique au fils de l'eau. Pour prendre en compte cette difficulté, nous nous plaçons dans le contexte de l'algorithmique on-line (en ligne). Les données du problème à traiter ne sont donc pas connues dès le départ, mais révélées au fur et à mesure, sans aucune connaissance du futur. Pour chacun des problèmes on-lines traités, nous proposons des algorithmes que nous évaluons analytiquement, en fonction d'un (ou parfois plusieurs) critère(s) de performance.

National audience; Nous proposons dans cet article des algorithmes d'ordonnancement permettant à un opérateur d'un lien haut-débit de gérer des demandes de réservations provenant de ses clients. Nos propositions ont les avantages suivants : (1) elles permettent de gérer les demandes à la volée, dès qu'elles arrivent à l'opérateur ; (2) nous prouvons qu'elles permettent d'approcher à de faibles facteurs multiplicatifs près, le profit maximum atteignable et, simultanément, le nombre maximum de clients pouvant être servis ; (3) ces facteurs sont ajustables et permettent à l'opérateur de donner plus d'importance relative à l'un ou l'autre des critères.

The early Eocene (c. 56 - 48 million years ago) experienced some of the highest global temperatures in Earth’s history since the Mesozoic, with no polar ice. Reports of contradictory ice-rafted erratics and cold water glendonites in the higher latitudes have been largely dismissed due to ambiguity of the significance of these purported cold-climate indicators. Here we apply clumped isotope paleothermometry to a traditionally qualitative abiotic proxy, glendonite calcite, to generate quantitative temperature estimates for northern mid-latitude bottom waters. Our data show that the glendonites of the Danish Basin formed in waters below 5 °C, at water depths of, Nature Communications, 11 (1), ISSN:2041-1723

"Shell chemistry of the Boreal Campanian bivalve Rastellum diluvianum (Linnaeus, 1767) reveals temperature seasonality, growth rates and life cycle of an extinct Cretaceous oyster" published in Biogeosciences

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Tese de mestrado, Engenharia Informática, Universidade de Lisboa, Faculdade de Ciências, 2008, Este documento descreve o trabalho realizado no âmbito da disciplina de Projecto em Engenharia Informática do Mestrado em Engenharia Informática da Faculdade de Ciências da Universidade de Lisboa. Recuperação de Informação Musical é, hoje em dia, um ramo altamente activo de investigação e desenvolvimento na área de ciência da computação, e incide em diversos tópicos, incluindo a classificação musical por géneros. O trabalho apresentado centra-se na Classificação de Pistas e de Géneros de música armazenada usando o formato MIDI. Para resolver o problema da classificação de pistas MIDI, extraimos um conjunto de descritores que são usados para treinar um classificador implementado através de uma técnica de Máquinas de Aprendizagem, Redes Neuronais, com base nas notas, e durações destas, que descrevem cada faixa. As faixas são classificadas em seis categorias: Melody (Melodia), Harmony (Harmonia), Bass (Baixo) e Drums (Bateria). Para caracterizar o conteúdo musical de cada faixa, um vector de descritores numérico, normalmente conhecido como ”shallow structure description”, é extraído. Em seguida, eles são utilizados no classificador — Neural Network — que foi implementado no ambiente Matlab. Na Classificação por Géneros, duas propostas foram usadas: Modelação de Linguagem, na qual uma matriz de transição de probabilidades é criada para cada tipo de pista midi (Melodia, Harmonia, Baixo e Bateria) e também para cada género; e Redes Neuronais, em que um vector de descritores numéricos é extraído de cada pista, e é processado num Classificador baseado numa Rede Neuronal. Seis Colectâneas de Musica no formato Midi, de seis géneros diferentes, Blues, Country, Jazz, Metal, Punk e Rock, foram formadas para efectuar as experiências. Estes géneros foram escolhidos por partilharem os mesmos instrumentos, na sua maioria, como por exemplo, baixo, bateria, piano ou guitarra. Estes géneros também partilham algumas características entre si, para que a classificação não seja trivial, e para que a robustez dos classificadores seja testada. As experiências de Classificação de Pistas Midi, nas quais foram testados, numa primeira abordagem, todos os descritores, e numa segunda abordagem, os melhores descritores, mostrando que o uso de todos os descritores é uma abordagem errada, uma vez que existem descritores que confundem o classificador. Provou-se que a melhor maneira, neste contexto, de se classificar estas faixas MIDI é utilizar descritores cuidadosamente seleccionados. As experiências de Classificação por Géneros, mostraram que os Classificadores por Instrumentos (Single-Instrument) obtiveram os melhores resultados. Quatro géneros, Jazz, Country, Metal e Punk, obtiveram resultados de classificação com sucesso acima dos 80% O trabalho futuro inclui: algoritmos genéticos para a selecção de melhores descritores; estruturar pistas e musicas; fundir todos os classificadores desenvolvidos num único classificador., This document describes the work carried out under the discipline of Computing Engineering Project of the Computer Engineering Master, Sciences Faculty of the Lisbon University. Music Information Retrieval is, nowadays, a highly active branch of research and development in the computer science field, and focuses several topics, including music genre classification. The work presented in this paper focus on Track and Genre Classification of music stored using MIDI format, To address the problem of MIDI track classification, we extract a set of descriptors that are used to train a classifier implemented by a Neural Network, based on the pitch levels and durations that describe each track. Tracks are classified into four classes: Melody, Harmony, Bass and Drums. In order to characterize the musical content from each track, a vector of numeric descriptors, normally known as shallow structure description, is extracted. Then they are used as inputs for the classifier which was implemented in the Matlab environment. In the Genre Classification task, two approaches are used: Language Modeling, in which a transition probabilities matrix is created for each type of track (Melody, Harmony, Bass and Drums) and also for each genre; and an approach based on Neural Networks, where a vector of numeric descriptors is extracted from each track (Melody, Harmony, Bass and Drums) and fed to a Neural Network Classifier. Six MIDI Music Corpora were assembled for the experiments, from six different genres, Blues, Country, Jazz, Metal, Punk and Rock. These genres were selected because all of them have the same base instruments, such as bass, drums, piano or guitar. Also, the genres chosen share some characteristics between them, so that the classification isn’t trivial, and tests the classifiers robustness. Track Classification experiments using all descriptors and best descriptors were made, showing that using all descriptors is a wrong approach, as there are descriptors which confuse the classifier. Using carefully selected descriptors proved to be the best way to classify these MIDI tracks. Genre Classification experiments showed that the Single-Instrument Classifiers achieved the best results. Four genres achieved higher than 80% success rates: Jazz, Country, Metal and Punk. Future work includes: genetic algorithms; structurize tracks and songs; merge all presented classifiers into one full Automatic Genre Classification System.