190 



THE TRIAS AND JURASSIC EPOCHS. 



which the vosgean sandstone was upheaved, Vosges and the Black 

 Forest underwent a little change in shape ; but other lands in 

 Europe have undergone scarcely any modification. We observe 

 only a secondary elevation of the central plateau of France by th 

 porphyroid granites of Lozere, by the hiils which edge the coal 

 formation from Fins to Mauriac. Subsidences occurred, on the 

 other hand, in Bourbonnais and Rouergue, as well as in lands be- 

 tween Toulon and Nice. Vegetation then underwent great modifi- 

 cations ; the ferns and equisitacese of great height had considera- 

 bly diminished, and coni'fers, on the contrary, became more 

 numerous : plants analogous to za'mia, and perhaps to cy'cas 

 (figs. 305, 806), then formed an important part of the flora of 

 Europe, being a prelude to the immense development they took in 

 the succeeding epoch. 



Fig. 305. Za'mia pungens. Fig. 30 fi. Cy'cas revoluta. 



In this epoch new saurians appeared, and traces of birds, which 

 had not appeared in preceding epochs, are recognised. It was at this 

 period also that those creatures existed, whatever they were, whose 

 tracks are found imprinted on bunter sandstein, freshly lifted above 

 water. Mr. Owen, who considers them enormous batrachians, 

 supposes them to have been of the form represented (Jig. 307). 



The jura'ssic epoch. At the time of the elevation of Thurin- 

 gerwald the tria'ssic formation, which had just been deposited 

 beneath the sea, was upheaved at different points ; some patches 

 ,of bunter sandstein were added around the central plateau of 

 France, between Moulins and La Chatre, between Brives and 

 Tulle, in the environs of Rodez, of Saint-Affrique and of Lodeve. 



