Late Carboniferous (Kasimovian and Gzhelian) Fusulines of the Ichinotani and Mizuyagadani Formations in the Fukuji Area, Hida Marginal Terrane, Central Japan

Abstract. Fusuline biostratigraphy and faunal composition of the upper part the Ichinotani Formation and lower part of the Mizuyagadani Formation in the Fukuji area, central Japan are reexamined and compared to those of previous works. The upper part of the Upper Member of the Ichinotani Formation is composed mainly of the upper Kasimovian and lower Gzhelian strata, and is characterized by the partial reappearance of Moscovian strata dominant in the lower part of the Upper Member, suggesting a more complicated geological structure of the formation than previously assumed. Fusulines apparently correlatable to the middle part of the Kasimovian have not been found in the Fukuji area. The species Carbonoschwagerina morikawai is restricted to the lower part of the Mizuyagadani Formation. Faunal composition and correlation of age-diagnostic fusuline species are reviewed paleobiogeographically between the Fukuji and other areas especially of the Akiyoshi Limestone. Described herein are two species of non-fusuline foraminifers and nine species of fusulines including Montiparus japonicus sp. nov.