THE PLEISTOCENE OR GLACIAL PERIOD. 495 



marine life of the cold northeastern coast was, at the close of the Cham- 

 plain, merging into the existing forms, and these were shifting north, 

 ward into their present habitat. 



Marine life on the more southerly coasts. — Away from the imme- 

 diate influences of the ice-sheets, the record of marine life does not 

 indicate any profound departure from the progressive modernization 

 that had been in progress through the Tertiary period. It has been 

 remarked by Dall that the Pleistocene fauna on the Atlantic coast 

 does not imply as cold waters as did the Oligocene fauna, and by Arnold 

 that the Pleistocene fauna of the California coast does not imply as 

 cool a climate as does the Pliocene fauna of that coast. It is to be 

 noted, however, that the known marine record does not presumably cover 

 more than a small part of the Pleistocene period, and that it is not 

 at all certain, or perhaps even probable, that the portion represented 

 was any one of the glacial epochs. When the ice was pushing into 

 the ocean on the coast of Maine, as in the Late Wisconsin epoch, and 

 an arctic fauna occupied that coast, it is scarcely probable that a warm- 

 temperate fauna lived on the southern coast; nor is it probable that, 

 when all the inlets of the coast of British Columbia, from Juan de 

 Fuca northward, were shedding icebergs into the Pacific, a warm- 

 temperate fauna lived along the California coast; but warm-tem- 

 perate faunas on those coasts are entirely consistent with such inter- 

 glacial climates as are represented by the Don beds, and they might 

 also have been quite consistent with the conditions that prevailed 

 just before or just after the glacial stages. These last fall within the 

 broader limits of the Pleistocene period, as it is usually defined in the 

 marine series. These limits probably do not correspond very closely 

 with the glacial limits which are usually adopted for the land series, 

 wherever glaciation prevailed. 



The Terrestrial Life oj the Non-glacial Regions. 



As previously indicated, the land life of the regions distant from 

 the glaciated areas cannot at present be correlated closely with the 

 glacial and interglacial stages, and must be treated more generally. 

 One of its most marked features consisted of a northern group of indi- 

 genous and Eurasian origin, that appears to have been driven far 

 south during the stages of ice advance, and to have followed the retreat- 



