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International audience; French Lower Devonian floras are rare, especially compared to certain other Western European countries. In this study, we reassess an assemblage collected in the 1930s in the Rebreuve quarry (Pas-de-Calais, northern France). We describe new features in several taxa and update taxonomic names from original descriptions. For instance, re-examination of vegetative remains previously described as Psilophyton princeps, led to the discovery of fertile structures allowing us to refer these specimens to Sawdonia. In total, this flora consists of ten taxa, including up to four different Psilophyton species, such as P. parvulum. Other taxa include Danziella artesiana, Drepanophycus cf. spinaeformis, Sporogonites exuberans and some specimens of Taeniocrada and Sciadophyton, revealing a diverse Lower Devonian plant assemblage. The Rebreuve assemblage represents a typical Emsian flora from Laurussia and bears striking resemblance with coeval Belgian assemblages. Previous palynological investigations, in addition to the similarities with well-dated Belgian floras, suggest an early Emsian age for this assemblage. The paleogeographical implications of findings are discussed.

International audience; Our understanding vegetation changes around the devonian-carbonierou boundary remains limited by the smell number of plant-bearing deposits close in age to the boundary.

International audience; In 1870, Schimper documented an anatomically preserved lycopsid cone found near the town of Cabrières, in the Hérault region of France. Since this initial report, over 500 specimens have been collected from Tournaisian (early Mississippian) outcrops in this area. They include permineralized specimens from the radiolarian cherts and associated phosphatic nodules of the Lydiennes Formation, and a hundred compressions in argilites, some with cellular preservation. Here we provide an updated review focused on the plants from the cherts, based on a database of 441 specimens corresponding to stems (66%), leaves/petioles (27%), fertile structures (4%), and roots (1%).Seed plants are by far the most abundant and diverse group of plants and constitute approximately 64% of the specimens assignable to that group. Some genera such as Calamopitys, Stenomyelon, Tristichia, Eristophyton, Lyginorachis, Kalymma and Periastron are also found in other Late Devonian-Mississippian localities. Four genera are only documented to date in the Montagne Noire: Faironia, Lyginopitys, Triichnia, and Coumiasperma, the latter being the only seed known in the chert. Lycopsids, cladoxylopsids, and zygopteridalean ferns each represent about 10% of the specimens. Lycopsids include different types of stems and two species of Flemingites (Lepidostrobus). Cladoxylopsids are represented by stems assignable to a single genus, Cladoxylon. Zygopteridalean ferns include many types of Clepsydropsis petioles/ phyllophores; their diversification is interpreted as evidence of early radiation preceding the emergence of two clades, one leading to the quadriseriate zygopteridaleans and the other to the biseriate ankyropterid/tedeleans. The less abundant groups are the progymnosperms and sphenopsids, each corresponding to 1-2% of the specimens. Sphenopsids are only represented by small stems of Sphenophyllum. The progymnosperms include vegetative and fertile remains assigned to Protopitys, and the putative progymnosperm stem Stauroxylon, which is currently being reinvestigated. The plants from the Montagne Noire constitutes one of the few well-dated middle Tournaisian floral assemblage in the world. As such, they provide key information on plant evolution, especially the diversification of ferns s.l. and seed plants. They also document floral changes between the Devonian and the Carboniferous, with the presence of a mixture of taxa belonging (1) to groups that were abundant and diverse during the Devonian and disappeared during the Carboniferous, such as the cladoxylopsids and progymnosperms, and (2) to groups that appeared in the late Devonian and diversified to become emblematic members of Carboniferous floras, such as the Sphenophyllales, the zygopteridalean and tedelean ferns, and the seed plants.

Supplementary Material 1: Detailed stratigraphic sections of the Agua de Lucho and Cerro Tres Cóndores Formations in the Agua Quemada Syncline, SW Sierra de Las Minitas (see Fig. 1 for location).

International audience; The Mississippian was an important time in plant evolution, with the diversification of several groups, especially among the ferns s.l. and seed plants. The Montagne Noire localities in southern France include some of the oldest outcrops with anatomically preserved fossil plants from that time. The plant remains occur within the Lydienne Formation, which corresponds to alternating beds of argillaceous rock and radiolarian cherts that contain phosphatic nodules deposited in a shallow sea. The horizons containing plant fossils are considered middle Tournaisian in age based on the conodonts (Galtier et al., 1988).Since the first study of an anatomically preserved Lepidostrobus cone by Schimper in 1870, more than 30 taxa have been identified in the Lydiennes formation (e.g., Böhm, 1935; Bertrand et al., 1935; Galtier, 1970; Meyer-Berthaud, 1984; Galtier et al., 1988; Galtier & Rowe, 1989; Rowe & Galtier, 1989, 1990; Galtier et al., 1993; Decombeix et al., 2006, 2008). Ongoing work on this material aims to provide a better understanding of plant diversity in the Early Mississippian and to elucidate their systematic relationships with better-known Late Devonian and Late Mississippian taxa. Here we present (1) a synthesis of plant diversity in the Montagne Noire and how it compares to Devonian-Mississippian floras from around the world, (2) three examples of recently (re)investigated taxa and how they contribute to our understanding of plant evolution, and (3) remaining questions and future directions. The Montagne Noire anatomically preserved flora is largely dominated by seed plants, which represent more than half of the total number of collected specimens. Zygopteridalean ferns, cladoxylopsids, and lycopsids are also relatively abundant (+/- 10%) while the progymnosperms and sphenopsids are exceptionally rare (1–2%). Reproductive structures are rare (4–5 %) and the majority of the specimens are leaves and stems (Galtier et al., 1988). The latter range from minute axes less than a millimeter in diameter to wood fragments indicating the presence of arborescent taxa. A number of genera found in the Montagne Noire also occur in younger (Late Tournaisian-Viséan) localities (e.g., Stenomyelon, Eristophyton) and a few are known in both Devonian and younger Mississippian localities (e.g., Sphenophyllum, Cladoxylon). Interestingly, there are also some genera that are to date only known in the Montagne Noire such as the seed Coumiasperma, or the seed plant stems Faironia and Lyginopitys. The closest flora in terms of composition is from the Saalfeld area in Thuringia, Germany which is likely coeval. Recent (re)investigations of specimens from the Montagne Noire have provided important information on several key plant genera. One example is Sphenophyllum, a scrambling to lianescent sphenopsid genus known from the Late Devonian to the Triassic and a major component of Pennsylvanian coal swamp floras. The Montagne Noire specimens provide new information on the anatomy of Mississippian representatives of Sphenophyllum, which are poorly known in part due to the small number of permineralized specimens from that time (Terreaux de Félice et al., in revision). The Montagne Noire flora also contains several specimens that can be assigned to the enigmatic progymnosperm Protopitys, an arborescent genus currently known from the Mississippian localities of Canada, Scotland, France, Germany, Australia, and possibly the US (Decombeix et al, 2015). Of particular importance is a branching system bearing sporangia with preserved spores. This specimen represents the third fertile specimen ever reported for the genus and is the best preserved and the oldest one known to date. Ongoing studies will provide new information and insight to assess the affinities of Protopitys. Finally, some plants from the Montagne Noire display a unique combination of characters that challenges our understanding of Devonian-Carboniferous plant relationships and their stratigraphic distribution. This is the case for Stauroxylon (Galtier 1970), an enigmatic genus currently being reexamined that could represent the youngest occurrence of an aneurophytalean progymnosperm, a group typically known in the Middle and Late Devonian and thought to have gone extinct by the end of the Frasnian. Future work will focus on the description of unpublished specimens from the Université de Montpellier collections and collecting of new material. While plant remains are rare in the Lydienne formation, they have the potential to provide key information on plant evolution. As one of the oldest Mississippian deposits with anatomically preserved plants, the Montagne Noire is also a crucial source of information on floral changes around the Devonian-Carboniferous boundary.

The geological sciences at the University of Liège: two centuries of evolution.Part 1: from the foundation to the First World War. By the time the University of Liège was founded in 1817, geology was a young science and the geological composition of the country was being unveiled. The works of precursors such as Robert de Limbourg were about to inspire the first generation of Belgian geologists, among which Jean-Baptiste Julien d’Omalius d’Halloy is the most renowned. Geology was not taught at the University of Liège before 1818, when Henri-Maurice Gaëde was appointed. He taught geology, mineralogy and crystallography as well as anatomy and botany. He was followed by Armand Lévy in 1828, then again by Gaëde in 1830, Philippe-Adolphe Lesoinne in 1831, Charles-Philippe Davreux 1834 and Michel Gloesener in 1834. Except the mineralogist Lévy, none of them conducted any geology-based research. Nevertheless, geological knowledge, especially palaeontology, progressed due to the work of scientists such as Philippe-Charles Schmerling who described the first fossil human in 1830. Geology became a true research area at the university with the arrival of André Dumont in 1835. Before his appointment as professor, Dumont had already proved his mastery of geology by publishing his Description géologique de la province de Liége which earned him the golden medal of the Academy of Sciences and Arts of Brussels and a great reputation. He was the first to demonstrate the stratigraphic succession of the strata (geognosy) and to trace those strata on a map to show how they correlate. A great field geologist, Dumont was appointed by the Belgian Government to map the geology of the country, providing the first geological map of Belgium and neighbouring areas as a whole in 1849. At the same period (1846), Laurent-Guillaume de Koninck was appointed to teach palaeontology. His expertise on all groups of fossil animals drove him to produce an impressive number of monographic publications, on Belgian material but also on collections sent to him from all over the world. His Faune du Calcaire carbonifère de la Belgique – of which only the six first volumes were published before his death – is by itself the most exhaustive study of Carboniferous invertebrates ever published. De Koninck was in conflict with Dumont about the utility of fossils in geology, the latter being persuaded that they were too variable to have any significance. However, de Koninck’s palaeontological methods were indeed necessary and led to the development of biostratigraphy. Both Dumont and de Koninck received the Wollaston medal from the Geological Society of London for their work. Their successor Gustave Dewalque became – in 1857 – professor of geology and palaeontology and combined the scientific views of both his predecessors to produce very detailed and holistic research. His palaeontological work on the Jurassic fossils of S Belgium is most remarkable but his main achievement was his geological map of Belgium and surrounding areas, replacing Dumont’s with a much higher level of details. To make the reading of the map easier, Dewalque wrote his masterful Prodrome d’une description géologique de la Belgique (1868), which is no less than an encyclopaedia on geology of Belgium. His name is also inseparable from two major achievements in Belgium. Firstly the production of a detailed geological map at the 1/40,000 scale for which he achieved scientific posterity. Secondly he was the founding character of the Société géologique de Belgiquein 1874 and was also Secretary General of the society for 25 years. For his tremendous works, Dewalque received the prestigious Hayden medal from the Academy of Natural Sciences of Philadelphia in 1899. During his academic life, Dewalque progressively delegated his teaching to his young collaborators who eventually replaced him: Alfred Gilkinet for Palaeobotany, Julien Fraipont for Palaeontology, Adolphe Firket for Physical Geography, Guiseppe Cesàro for Mineralogy, and Max Lohest for General and Applied Geology. Alfred Gilkinet was one of the first palaeobotanists to embrace the theory of evolution and to recognise it among his fossils. He had a particular interest on Devonian fossil plants but also described material from the Paleogene. He was moreover a pharmacist and the institute of Pharmacy of the University bears his name. Julien Fraipont first entered the university at the laboratory of biology led by Edouard Van Beneden and published several papers on marine organisms for him. His work on Devonian crinoids was rewarded by the Société géologique de Belgiqueaward and de Koninck chose him to collaborate to his monography on Carboniferous bivalves. Fraipont published several papers on Palaeozoic fossils, the most remarkable being his work on the exquisitely-preserved echinoderms from the Marbre Noir de Denée. Furthermore, Fraipont was, with his colleague Lohest, a palaeoanthropologist and archaeologist and both were responsible for many discoveries in Quaternary cave deposits, including in Spy. Lohest was first a palaeontologist and published several contributions to the Palaeozoic fishes from Belgium, including a mandible identified by him as being from a fish but now interpreted as a rare Ichthyostega-like tetrapod. He then focused only on geology and applied geology after his major discoveries; such as the phosphate deposits in Hesbaye area, his prevision of the existence of coal measure in a deep basin in N Belgium, his interpretation of the metamorphism in Ardenne and description of the boudinage phenomenon. With Julien Fraipont and Marcel de Puydt, he discovered and described the human remains from the Spy cave – remains they interpreted as belonging to a species distinct from ours and that they attributed to the Neanderthal ‘race’. They demonstrated, for the first time in history, the co-occurrence of a fossil human species, Mousterian lithic industries and Pleistocene megafauna. Adolphe Firket mainly taught Physical Geography but was involved in the geological study of the Belgian coal measures and various mineral deposits. Guiseppe Cesàro was the true founder of mineralogy and crystallography in Belgium. His works on calcites and phosphates were very advanced despite that he was a self-taught man. They are still used as references today as are his works on crystallography. All those great names were part of the University and Belgian geology history, as men, scientists and professors. They left us a considerable heritage that needs to be rediscovered.