Scientia Sinica

No. | SZE; CORRELATION & AGE OF YENCHANG FLORA 153

Podozamites, etc. It is evident that only the upper part of the Yenchang Formation can be possibly correlated with the Rhaetic horizons of Sweden.

The Tonking Coal Series in Indo-China, which is nearly equivalent to the Anyuan Coal Series in Pinghsiang, Kiangsi Province, and which is also characterized by a dominant assemblage of the Dictyophyllum-Clathropteris flora, comprises many important elements of the Yenchang flora, namely, Equisetites sarrani, Neocalamites carrerei, Cladophlebis raciborskit, Bernoullia zeillert, Ctenopteris sarrani, etc. It is also highly possible that Zeiller’s Noeggerathiopsis hislopi is identical with Glossophyllum? shensiense in the Yenchang flora and his Cladophlebis (Todites) roesserti is identical with our Cl. (Todites) shensiensis. In addition, Zeiller’s Podozamites distans recalls Podozamites lanceolatus from the Yenchang Formation. It is striking that the Yenchang flora has eight species in common with the Rhaeto-Liassic flora of Tonking. This surprising result may suggest the view that the upper part of the Danaeopsis-Bernoullia flora is probably equivalent in age to the lower part of the Dictyophyllum-Clathropteris flora. The species Bernoullia zeilleri is represented in the Tonking flora by very few small fragments which were described by Zeiller as Bernoullia sp. In Northern Shensi, this species occurs also very rarely in the basal part of the Lower Jurassic Wayaopu Coal Series which seems to overlie conformably the Yenchang Formation. The deposition of these two formations in Northern Shensi appears to be continuous without interruption.

The plant remains from Nariwa District in Japan were first described by Yokoyama’! in 1891. In 1932, the late Prof. Oishi?! described more than 80 species systematically and again in 1938, Oishi and Huzioka added to the Nariwa flora a certain number of new species. The Rhaeto-Liassic aspect of the Nariwa flora in Japan is, on the whole, very strong as is shown in the analysis of the flora in comparison with the Lepidopteris and Thaumatopteris zones of Eastern Greenland’. According to the present writer, the Nariwa flora is nearly equivalent in geological age to the Tonking flora of Indo-China as well as to the Pinghsiang flora of Southern China. It is also characterized by a dominant assemblage of the Dictyophyllum-Clathropteris flora. The Writer is in complete agreement with Prof. Oishi that the lower part of the Nariwa flora is of the Rhaetic age and that the upper part of it may belong to the Liassic. It should be pointed out that our Yenchang flora has also five Or SiX species in common with the Nariwa flora, they are: Cladophlebis gigantea, Cl. raciborski, Neocalamites carrerei, Swedenborgia cry ptomertoides, Podozamites lanceolatus and probably also Stenorachis (Ixostrobus?) honianus. All these identical forms are confined to the upper part of the Yenchang Formation.

Finally, it is of special interest to point out that the Yenchang flora in Northern Shensi comprises also a few identical forms of the Hsiangchi flora of western Hupeh which is evidently of the Lower Jurassic age. The identical