Biostratigraphy of the Akiyoshi Limestone Group,

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Yasuhiro Ota
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1. Protriticites subschwagerinoides Zone
2. Triticites montiparus Zone
3. Triticites schwageriniformis Zone
4. Triticites dictyophorvs Zone
5. Triticites shikhanensis compactus Zone
6. fteudaschwagerina mo/sej -
Robustoschwagerina xiaodushanica Zone
7. fteudoschwagerina parabeedei -
Sphaeroschwagerina sphaerica Zone
8. fteudoschwagerina robusta -
Zellia chengkungensis Zone
9. Pseudofusulina vulgaris -
laxifusulina iniqua zone
10. Chalaroschwagerina tumentis Zone
11. Pamirinachinlingensis Zone
Fig. 5. Composite stratigraphic section, showing fusulinacean faunas near the Carbonifer
ous-Permian boundary at Xiaodushan, Guangnan, Easter Yunnan (after Zhou et al.,
1987).
6. The top of the Baomoshan Formation, namely the Robustoschwagerina Zone is
correlated with the base of Artinskian Stage and it is regarded as the lowest part of
the Permian in China.
In Japan, the definition of the Carboniferous-Permian boundary also has been
discussed for a long time in several important provinces by many workers. The
author presents some recent considerations on this problem, by some workers in the
Akiyoshi Limestone Group.
Toriyama (1954a, b, 1958) divided the Akiyoshi Limestone Group into the
following seven fusulinacean zones in descending order.
Yabeina Zone
Neoschwagerina Zone
Parafusulina Zone
Pseudoschwagerina Zone
Fusulinella Zone
Projusulinella Zone
Millerella Zone
He subdivided the Pseudoschwagerina Zone into two subzones, the upper, the
Pseudofusulina vulgaris Subzone and the lower, the Triticites simplex Subzone. Then