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Geological records from the Antarctic margin offer direct evidence of environmental variability at high southern latitudes and provide insight regarding ice sheet sensitivity to past climate change. The early to mid-Miocene (23-14 Mya) is a compelling interval to study as global temperatures and atmospheric CO2 concentrations were similar to those projected for coming centuries. Importantly, this time interval includes the Miocene Climatic Optimum, a period of global warmth during which average surface temperatures were 3-4 degrees C higher than today. Miocene sediments in the ANDRILL-2A drill core from the Western Ross Sea, Antarctica, indicate that the Antarctic ice sheet (AIS) was highly variable through this key time interval. A multiproxy dataset derived from the core identifies four distinct environmental motifs based on changes in sedimentary facies, fossil assemblages, geochemistry, and paleotemperature. Four major dis-conformities in the drill core coincide with regional seismic discontinuities and reflect transient expansion of grounded ice across the Ross Sea. They correlate with major positive shifts in benthic oxygen isotope records and generally coincide with intervals when atmospheric CO2 concentrations were at or below preindustrial levels (similar to 280 ppm). Five intervals reflect ice sheet minima and air temperatures warm enough for substantial ice mass loss during episodes of high (similar to 500 ppm) atmospheric CO2. These new drill core data and associated ice sheet modeling experiments indicate that polar climate and the AIS were highly sensitive to relatively small changes in atmospheric CO2 during the early to mid-Miocene.

Until now, the only living species assigned. to the cancellariid genus Loxotaphrus Harris , 1897 was the West African species L. deshayesii (Duval, 1841). Two new living species are described here, L. limpusi n. sp., from the Swain Reefs, Queensland, and L. rosadoi n. sp., from off southern Mozambique. L. limpusi most closely resembles the type species of the genus, L. variciferus (Tate, 1888) (Miocene, southern Australia). Although L. rosadoi resembles L. variciferus and L. limpusi more closely than it does L.. deshayesii, it differs from all other species ,assigned to Loxotaphrus in having weak sculpture, apart from the prominent, sharp nodules around the peripheral keel.

Summary Three specimens from Queensland and five from northern Western Australia belong in the same species as the two paralectotypes of Triton pyriformis A. Adams, 1854, a species that has not been recognised since it was named, However the lectotype of Triton pyriformis is a specimen of Ranularia encaustica (Reeve, 1844), and the name is preoccupied by Triton pyriformis Conrad, 1849 (= Gutturnium muricinum Roding, 1798), and so the species is redescribed as Ranularla oblita n. sp.

The Fourth International Congress of Pacific Neogene Stratigraphy, was held July 29–31, 1987, at the University of California, Berkeley. This very successful congress was organized by the Regional Committee on Pacific Neogene Stratigraphy (RCPNS) of the International Union of Geological Sciences (IUGS) and the International Geological Correlation Program (IGCP) Project 246 “Pacific Neogene Events in Time and Space.” The meeting was attended by 180 scientists from 16 different countries, and more than 90 presentations were made, on topics ranging from paleoclimatology, biostratigraphy, regional stratigraphy and geologic history, new techniques in stratigraphy, evolutionary studies, and modern biofacies and sediment relationships. A. R. Edwards of the New Zealand Geological Survey (Lower Hutt, New Zealand) spoke on climatic events that he recognizes in the late Neogene strata of New Zealand. The carbon isotope shift during chron 6 (6.3–6.5 Ma) is identified in the sequence at Blind River (Marlborough, New Zealand). The extinction of ∼25% of New Zealand molluscan genera during the latest Micoene (Kapitean Stage) accompanied the greatly accelerated diversification of planktonic foraminifera lineages at this time. The New Zealand events are also coeval with the Messinian “salinity crisis” in the Mediterranean. A series of events (extinctions of Mollusca, appearance of glacial rock types, foraminifera speciation, and nannofossil appearances) in New Zealand late Pliocene rocks reflect the climatic deterioration. One type of sub-Antarctic molluscan fauna abruptly appeared in central North Island at 2.4 m.y., coeval with the onset of major Northern Hemisphere glaciation.