Scientia Sinica

150 SCIENTIA SINICA Vol. V

flora is roughly contemporaneous with our Yenchang flora of Northern Shensi. In this connection, it is of interest to point out that in Western Kazakstan, the Upper Triassic formation is overlain unconformably by a coal series (the so-called mxkeHMUIKe Series with a thickness of about 100 metres) which is undoubtedly the equivalent of the Lower and Middle Jurassic coal series in North China, and is also characterized by a dominant assemblage of Coniopteris hymenophylloides, Cladophlebis denticulata, Cl. whitbyensis, Cl. lobifolia, Phoenicopsis speciosa, Pityophyllum nordenskidldi, etc. This coal series has been regarded by Brick as belonging to the Middle Jurassic. The present writer is not quite prepared to regard it as proved; this coal series in Kazakstan, as has been stated above, is characterized by a dominant assemblage of the Coniopteris-Phoenicopsis elements and its geological age must be from the Lower to Middle Jurassic. It can be roughly correlated with the Wayaopu Coal Series (the upper part of which has now been called the Ishihtsun Coal Series) of Northern Shensi, the Tatung Coal Series in Northern Shansi and the Mentoukou Coal Series of Peking, which it resembles in making the maximum of coal formation of the Jurassic period. The flora of this coal series of Kazakstan cannot be said to contradict this parallelization. For the purpose of comparison, the composition of this Jurassic flora in Kazakstan may be mentioned below:

Gleichenites sphenopteroides Brick Coniopteris hymenophylloides (Brongn.) Sew. C. porcina Brick ex Ms.

C. sp. cf. C. fursenkoz Pryn.

Dictyophyllum sp.

Cladophlebis haiburnensis (L. et H.) Brongn. Cl. whitbiensis Brongn. var. punctata Brick Cl. sp: ex. gr. C. denticulata (Brongn.) Font. Cladophlebis lobifolia (Phill.) Brongn. Equisetites ferganensis Sew. sensu lato

E. halle: Thomas

Ptilophyllum cutchense Morris

Nilssonia vittaeformis Pryn.

N. compta (Phillips) Bronn

Phoenicopsis speciosa Heer

Ginkgoites sp.

Feildenia sp. :

Pagiophyllum peregrinum (L. et H.)

P. setosum (Phillips)

Pityophyllum angustifolium (Nath.) Moller Podozamites sp.

Conites sp. a.

Conites sp. b.