Published on: 1959-09
Hardcover
While taking geological investigations in Kwangsi from 1940-44, the writer and his colleagues of the Institute of Geology, Academia Sinica, discovered several fossil localities in the Triassic rocks in the western part of that province, where the ammonoids are not only rich in individuals but also rich in genera and species. The fossils are exclusively an ammonoid fauna. Among the hundreds of specimens in the collections there are only a few specimens of small pelecypods and nautiloids.
The lower Triassic rocks in western Kwangsi are composed largely of thin-bedded or nodular limestones attaining a thickness of about 100 metres, in which the fossils are very rare. However, at many places the limestones become thick-bedded and impure, in which the ammonoids are rich. They can easily be taken out from the rocks and most of them are fairly well preserved.
This report deals with the materials collected from twelve localities in five districtsof western Kwangsi: the Linglo, the Fengshan, the Tiengno, the Tunglan and the Tientung districts. The ammonoids described and illustrated amount to 204 species in 59 genera, which are grouped in 23 families, of which more than two-thirds are new formes
The study of these ammonoids reveals that the fauna is closely related to that of India and that of Albania in the Tethys Sea on the one hand, and is more closely related to that of Timor on the other. The Triassic ammonoids of Ussuri land and those of Eastern Siberia also show close connection with the fauna of Kwangsi. Although the faunas of these regions bear general resemblance, difficulties are usually met with when making precise correlation. The discovery of Lower Triassic ammonoids in Kwangsi is of particular importance, for they link the fauna of these distant regions. It is also found that many forms characteristic of early period persisted much longer in the Kwangsi province and some genera appear earlier in this region.
From the study of these ammonoids it is also recognized that the Lower Trias in Kwangsi can be subdivided into four divisions or groups. In ascending order they are as follows: the Gyronitan, the Flemingitan, the Owenitan and the Columbitan in the scheme of Spath’s classification. His lowest division, the Otoceratan, is not confirmed, whilst his uppermost division, the Prohungaritan or Olenikitan, is not junstified.
1. Introduction
2. The Boundary of the lower Trias
3. Fossil Localities
4. Subdivision of the Lower Trias in Kwangsi
5. Subdivision and Correlation of the Lower Trias in South China
6. Inter-Continental Correlation of the Lower Trias
7. Summary
8. Systematic Descriptions
(1) Suborder Prolecanitina
(2) Suborder Ceratitina
(3) Suborder Phylloceratina
9. Explanation of Plants
