FLOEA OF THE TEIAS AND LIAS EPOCH. 



747 



in the flora. Sigillarias and Lepidodendrons disappear, and in their 

 place we meet with Gym- 

 nosperms, belonging to the 

 genera Voltzia, Haidingera, r-^ 

 Zamites (fig. 927), Ctenis, 

 iEthophyllum, and Schizo- 

 neura (fig. 928). Species of 

 Neuropteris, Pecopteris, and 

 other acrogenous coal genera 

 are stiU found, along with 

 species of Anomopteris and 

 Crematopteris, peculiar Fern- 

 forms, which are not found in 

 later formations. Stems of 

 arborescent Ferns are more 

 frequent than in the next 

 period. 



In the Lias the essential 

 characters of the flora are the 

 predominance of Cycadacese, 

 in the form of species of Oycadites, Otozamites, Zamites, Ctenis, 

 Pterophyllum (figs. 929, 930), and Nilssonia, and the existence 



Fig. 928. 



among the Ferns of many genera with reticulated vernation, such as 

 Camptopteris and Thaumatopteris, some of which began to appear at 



Fig. 927. Zamites. Leaf of a fossil Cycad. 

 of the fossil coniferae of the Triassic system. 



Fig 923. Sohizoneura heterophylla, one 



