Scientia Sinica

148 SCIENTIA SINICA Vol. V

form in the Yenchang flora is of interest, and may afford evidence of considerable weight to the Older Mesozoic age of this formation.

The composition of the Yenchang flora bears, moreover, a striking resemblance to the two Upper Triasic or Keuper floras described recently by Brick! from Western Kazakstan. The lower plant-bearing series is named the Hypariacaitekam Series with a thickness of about 250-300 metres. It contains the following forms:

Danaeopsis marantacea (Presl) Heer Danaeopsis emarginata Brick Danaeopsis bipinnata Brick

Danaeopsis angustipinnata Brick Bernoullia aktiubensis Brick

Todites roesserti Zeiller

Polypodites cladophleboides Brick Cladophlebis simplicinervis Brick Cladophlebis tripinnata Tur-Ket ex Ms. Equisetites arenaceus (Jaeger) Schenk _Lepidopteris ottonis (Goepp.) Schimper Callipteridium remotum Brick

Aipteris nerviconfluens Brick Thinnfeldia sp.

Taeniopteris angustifolia Schenk Sphenozamites surakaicus Prynada ex Ms. Yuccites spathulatus Prynada ex Ms. Yuccites uralensis Prynada ex Ms. Araucarites convexus Brick Sagenopteris ilekensts Brick

Ixostrobus sp. cf. I. groenlandicus Harris Swedenborgia cryptomerioides Nathorst

The upper series is called the Kypaitmauckan Series with a thickness of about 40-45 metres. This formation has been regarded as a transitional horizon between the Upper Triassic and the Lower Jurassic. According to Dr. Brick, it belongs also to the Upper Triassic. It contains the following forms:

Xylomites zamites Geopp.

Danaeopsis hughes: Feistm.

Bernoullia aktiubensis Brick

Todites roesserti Zeiller

Diplozites kazachstanicus Brick

Cladophlebis szerana P’an

Cladophlebis aktiubensis Tur-Ket. ex Ms. Rhacophyllum pachyrhachis (Schenk) Schimper Lepidopteris ottonis (Goepp.) Schimper