i8o Evolution and Distribution of Fishes 



The preceding chart (Fig. 23) sets forth the views of de 

 Lapparent and successors. It shows that two compact 

 expanses of dry land existed, such as might give opportunity 

 for migration and evolving adaptation of plant and animal 

 types over the greater part of what are now more or less 

 sharply separated continents. So, as during previous 

 epochs, one might expect to find a certain correlated simi- 

 larity in structural advance, in taxonomic affinity, and in 

 adaptation to environment of varying character. Such 

 also is largely true. 



On the American continent, it is now agreed by geolo- 

 gists and palaeontologists that the Triassic drylands, fresh- 

 water lakes, and river systems with their flood-plains, 

 covered an extensive territory, that can still be fairly ac- 

 curately traced east of the Alleghanies from Canada to 

 the Gulf, also southward through Brazil to Chile and the 

 Falkland Isles. But so far as one can judge from fossil 

 remains, the geologic period represented, seems to be that 

 of the Upper Keuper and the Rhaetic of Europe. It may 

 therefore be that in the period between the Permian and 

 the Rhaetic extensive land denudation may have proceeded, 

 while marine strata were being enormously accumulated 

 in the west, from Alaska and British Columbia southward 

 to California and Idaho. 



In contrast to his views on Devonian fish life Newberry 

 consistently advocated a freshwater or even more an estua- 

 rine environment, in his study of "Fossil Fishes and Fossil 

 Plants of the Triassic rocks of New Jersey and the Con- 

 necticut Valley" {1^4). These rocks, now usually known 

 as the Newark series, he regarded as having been laid down 

 during the latter half of the Triassic age, and so in the 

 Upper Keuper or in the Rhaetic period. They extend in 

 a north-east and south-west direction, parallel to the Al- 

 leghanies, and may represent the deposits laid down in 

 some great lake that extended from Nova Scotia to the 

 Carolinas, or even to the present Gulf of Mexico. The 

 deposit varies from 2000 to 5000 feet in thickness, and is 

 largely composed of red sandstones, shales and micaceous 

 deposits. Most of these are barren in fossils, or show only 

 scanty remains. We accept it that they were wholly fresh- 



