舞鶴層群から産出したFollicucullus(ペルム紀放散虫)

西南日本内帯の舞鶴帯に分布する舞鶴居群に含まれる放散虫を検討し,Follicucullus monacanthusおよびFo. scholasticusの2群集を識別した.ここではこの2群集を特徴付けるFollicucullus ORMISTON and BABCOCKの2種を記載するとともに舞鶴帯でのこの放散虫化石発見の意義についてふれた.Follicuculluss scholasticus群集帯は,紡鍾虫にもとづく化石帯のうちLepidolina kumaensis帯の一部に対比される.また,舞鶴層群の年代は本報告地域の北に分布する下見谷層の年代よりも若いといえる.

Two radiolarian assemblages, namely, Follicucullus monacanthus and Fo. scholasticus assemblages are discriminated within the Permian Maizuru Group in the Maizuru Belt, Southwest Japan. The species of Follicucullus ORMISTON and BABCOCK, representing these assemblages, are described and the significance of this discovery in the Maizuru Belt is briefly discussed. The Follicucullus scholasticus Assemblage Zone is probably correlated with some part of fusulinid-zone, Lepidolina kumaensis. The age of the Maizuru Group is regarded to be younger than that of the Shimomidani Formation which is distributed in the area adjacent to the north of the study area.