494 THE TRIASSIC PERIOD 



of the known American fossils belong to this stage. The Richmond 

 coal-beds of the Newark series, probably the product of marsh 

 vegetation, contain great numbers of equiseta and ferns, but almost 

 no conifers and few cycadeans. 



Land animals. The physical conditions of the Permian and 

 Triassic periods were so similar that adaptation to the conditions of 

 the first would seem to have been a fitting preparation for life in the 

 second. Yet, in spite of this fact, there was a great break in the 

 succession of land life, so far as the known record shows. What 

 became of the Permian vertebrate faunas of North America is un- 

 known, for between the horizons yielding Permian fossils of land 

 animals, and those yielding Upper Triassic fossils of land animals, 

 there are great thicknesses of red sandstone barren of fossils of all 

 sorts, so far as now known, and the later fauna does not appear to 

 have descended from the Permian. In Africa there appears to have 

 been a much less serious break between the land life of the two 

 periods. In other continents few Early and Middle Triassic fossils 

 of land life have been found, but the life of the Upper Trias is better 

 known. During the period many types were initiated, while only a 

 few reached their maximum development. 



There is abundant proof of the mingling of European and 

 American land faunas late in the period, for at this time there were, 

 in North America, representatives of groups that had lived in 

 Europe since the early Permian, but which had never before ap- 

 peared in our continent, so far as now known. 



Though still numerous the amphibians had lost the foremost 

 place they held in the Permian. Before the close of the period they 

 entered upon a rapid decline from which they never recovered. 

 Ancestors of the whole tribe of terrestrial vertebrates, they soon 

 became its most insignificant representatives. 



Reptiles evolved rapidly. The branch with the mammalian 

 strain (p. 478, Fig. 418) seems to have been left far behind by the 

 more distinctively reptilian branch, which developed greatly later 

 in the period when the dryness was ameliorated and vegetation began 

 again to flourish. Before the close of the period, every important 

 group of the class was represented. Crocodilians, flying saurians, 

 and the scaled reptiles (lizards, snakes, etc.) came in near the close 

 of the period, as some of the older types were disappearing. 



A foremost feature of the life was the advent and rapid evolu- 

 tion of the dinosaurs (terrible saurians). At first they were of 



