"舞鶴帯"下見谷層からのペルム紀放散虫およびコノドントの発見とその意義

筆者らは"舞鶴帯"に分布する下見谷層より中期ペルム紀(おそらくレオナルド世)の放散虫とコノドントを得た.本論文では,化石発見の意義についてふれるとともに,筆者の1人石賀は4種の放散虫と3種のコノドント(内,1種は新種)を記載した.下見谷層の年代は舞鶴層群のそれよりも古く,丹波帯に分布するペルム系とは岩相が異なる.すなわち,下見谷層は主に砕屑岩からなるのに対し,丹波帯のそれは緑色岩チャートを主とする.

The authors obtained middle Permian (possibly Leonardian) radiolarians and conodonts from the Shimomidani Formation in the "Maizuru Belt." Four radiolarian species and three conodont species (including one new species) are described by H. ISHIGA and the authors discussed the significance of this discovery. The age of the Shimomidani Formation is older than that of the Maizuru Group and the Shimomidani Formation is quite different from the Permian formation in the Tamba Belt in that the former is mainly composed of clastic materials, while the latter is represented by greenstone-chert.