化石

Limestone blocks yielding corals, foraminifers and other fossils are embedded in the Lower Cretaceous Ishido Formation of the Sanchu Group. These limestone blocks also contain oncoids consisting of calcibionts. Limestones are lithologically classified into floatstone and mudstone. Occurrence of planktonic foraminiers such as Globuligerina hoterivica (Subbotina), Hedbergella planispira (Tappan), and Globigerinelloides aff. blowi (Bolli) indicates the age of limestone blocks as Early Aptian. Previously, a late Hauterivian to late Barremian age was assigned to the Ishido Formation based on ammonoids. This ammonoid age contradicts the age indicated by planktonic foraminifers. The depositional environment of these limestones is thought to be patch reef based on the oncoid facies and occurrence of microencruster, Bacinnella-Lithocodium association.

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The distributions of modern benthic foraminiferal assemblages were investigated in Ise and Mikawa bays, Japan, using surface sediments collected in September 2007. Forty seven species belonging to 40 genera were identified from Ise and Mikawa bays. Agglutinated species were dominant in the inner part of Ise and Mikawa bays, while calcareous species were dominant in the central part of Ise Bay. Significant shifts of assemblages were found in comparison with the distribution from surface sediments collected in 1940 from Ise Bay; calcareous species were replaced with agglutinated species in the inner part and the composition of calcareous species had changed completely in the central part. These results suggest that the present bottom environments are more eutrophic and anoxic than they were 67 years ago. Indicator species also suggested that Ise Bay is presently more eutrophic and anoxic than Mikawa Bay. A comparative study of distributions in Tokyo and Osaka bays demonstrated several similarities, while regional characteristic also were found there.

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In commemoration of the 75th anniversary of the Palaeontological Society of Japan, I review early women paleontologists in Japan. In 1907, the English birth control pioneer, Marie Stopes (1880-1958) came to Japan to study plant fossils. In 1910 she wrote on Cretaceous plants in Hokkaido. In 1928, a botanist Kono Yasui (1880-1971) got a doctoral degree in science, the first one in Japan given to a woman, by studying lignite and coal in Hokkaido. In 1937 and 1947, a high-school teacher, Yone Matsumoto, wrote at least two papers on paleobotany. It was 1943 when the first woman paleontologist Takayo Fujiwara (1916-1992) attended at the Geological Society of Japan. She studied biochemistry of organic matters in fossils. Tomoko Hayami (1943-1988) was the first woman that published the studies on bryozoan fossils in 1970 and 1971 from the Palaeontological Society of Japan.

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