All the Palaeozoic formations of the Japanese Islands are marine in origin and are grouped into two systems, Kitakami and Titibu. Whereas, the Kitakami system includes Gotlandian and Devonian formations, with the exclusion of the uppermost part of the latter, the Lower, Middle, and Upper Titibu approximately correspond to the Lower Carboniferous, Upper Carboniferous, and Permian respectively, essential divergence being the inclusion of the uppermost Devonian rocks into the Lower Titibu, of the Upper Visean stage into the Middle Titibu, and of the
Triticites zone into the Upper Titibu, as shown in the table at the end of Pt. I.
All of the fusulinid zones, from the
Millerella zone to the
Yabeina zone, are represented in Japan. The faunas of the Carboniferous fusulinid zones are here briefly reviewed. It appears as if each couple of
Millerella and
Profusulinella zones,
Fusulinella and
Fusulina zones, and
Triticites and
Pseudoschwagerina zones intimately combined palaeontologically and stratigraphically, according to the informations now at disposal.
There are coral faunas of three different types; 1, the Akiyosi Fauna (
Nagatophyllum-Clisaxophyllum-Taisyakuphyllum fauna), ranging from the “endothyroid” zone to the
Fusulinella zone; 2, the Onimaru fauna (
Dibunophyllum-Kueichouphyllum-Hexaphyllia fauna) of the
Millerella zone; 3, the Hukuzi fauna (
Cystophora-Arachnastraea fauna) of the
Fusulinella zone. Minato already stressed on the Australian affinity of the brachiopod fauna of the Hikoroiti and Arisu formations of the Lower Titibu, and the South Chinese affinity of the Onimaru and Akiyosi coral faunas (M. Minato). On the other hand, the Hukuzi coral fauna is allied with those of the Penchi series of South Manchuria, Koten series of Korea, and the equivalent formations of the Moscow basin.
Hexaphyllia of the Onimaru coral fauna, and
Seccamminopsis in its association are known from the British Isles and Soviet Russia, and the latter also from Germany.
Leptophloeum from the Nakakura formation of the Lower Titibu closely resembles
L. australe McCoy from the Upper Devonian of Australia
and
Sinospirifer from the former has its relatives in the Upper Devonian of South China and Australia.
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