The Goshonoura Group which is distributed in Shishijima island, Kagoshima Prefecture, is divided into five units, i. e., S-I, S-II, S-III, S-IV and S-V Formations (Tashiro and Matsuda, 1984). The following characteristic bivalve faunas or bivalve assemblages occur in these formations : S-Ia, b Members : brackish water fauna (Pseudasaphis japonica assemblage) S-Ic Member : near-shore and offshore faunas (near-shore : Pterotrigonia (Ptilotrigonia) ogawai assemblage) (offshore : P. (Ptil.) obsoleta assemblage) S-II Formation : brackish water fauna (Costocyrena mifunensis assemblage) S-IIIa Member : near-shore or subtidal fauna ("Nipponitrigonia kikuchiana" assemblage) S-IIIb Member : offshore fauna (P. (Ptil.) imanishii assemblage) S-IV Formation : near-shore fauna (P. (Ptil.) mifunensis assemblage) S-Va Member : intertidal, near-shore and offshore faunas (near-shore : Glycymeris (Hanaia) goshonouraensis assemblage) (offshore : P.(Ptil.) monobeana assemblage) (intertidal : P.(Ptil.) tamurai assemblage) S-Vb Member : brackish water and intertidal faunas (intertidal : P. (Ptil.) tamurai assemblage) (brackish water : "Hayamina" sp. assemblage) Many of these faunas or assemblages are also found in the Lower-Middle Cenomanian strata of other areas of Japan, e. g. Goshonoura Group of Goshonoura island, Mifune Group, Fukigoshi Formation, Nagase Formation, Miyanohara Formation, Ougai Formation, Misakubo Formation, sandstone off the coast of Kuji, and Middle Ezo Group of Mikasa.
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