FLORA OF THE TRIAS AND LIAS EPOCHS. 



79 



^thophyllum, and Schizoneura (Fig. 7Q). The genus Yoltzia 

 is confined to the Trias, and though a true conifer, it is not 

 easy to correlate it with any living form. It is apparently 

 Abietineous, having two seeds to each scale, but they are 

 placed on the dilated upper portion of the scale. The leaves 

 are of two kinds, the one broad and short, and the other at 

 the tops of the branches long and linear. Species of Neu- 

 ropteris, Pecopteris, and other acrogenous coal genera are 

 still found, along with species of Anomopteris and Crenia- 

 topteris — peculiar Fern-forms, which are not found in later 

 formations. Stems of aborescent Ferns are more frequent 

 than in the next period. 



The Jurassic period of Brongniart embraces the Keupric 

 period or variegated marls of the Triassic system, the Liassic 

 epoch, the Oolitic and the Weal den. The flora of the 

 Keupric epoch differs from that of the Gr^s bigarre of the 

 Vosges. The Acrogens are changed as regards species, and 

 frequently in their genera. 

 Thus we have the genera 

 Camptopteris, Sageno- 

 pteris, and Equisetum. 

 Among Gymnospenns, 

 the genera Pterophyllum 

 and Taxodites occur. 



In the Lias the essen- 

 tial characters of the flora 

 are the predominance of 

 Cycadacef©, in the fonn of 

 species of Cycadites, Oto- 

 zamites, Zamites (Fig. 77), 

 Ctenis, Pterophyllum (Fig. 78), and Nilssonia (Fig. 79), 

 Palasozamia (Fig. 80), and the existence among the Ferns of 



Figs. 77 to 81. Cycadacese of the Jurassic epoch of Brongniart, 

 and of the Oohte. Fig. 77. Zamites, one of the fossil Cycadacese. 



Fig. 77. 



