558 CENOZOIC TIME — MAMMALIAN AGE. 



line ; (2) the terracing of the borders of the lakes and rivers over 

 the middle and northern latitudes of the continent; (3) the re- 

 ducing of the^ level of the rivers nearly to that of their present 

 channels and flood-plains. 



Champlain and Terrace Epochs in Foreign Countries. 



Vast alluvial deposits subsequent in origin to the Drift of the 

 Glacial period, and river and lake terraces, are as much a general 

 feature of Britain and Europe as of North America ; and, moreover, 

 the phenomena are most remarkable over the more northern lati- 

 tudes. But the fact that glaciers have been perpetual in Europe 

 since the Glacial period, and the general complexity of geological 

 movements about that corner of the Orient, make it more difficult 

 to locate the particular cases in the special epoch to which they 

 belong, or to separate them from the results of modern changes. 



The terraces in Great Britain, and especially its northern part, 

 Scotland, are on a grand scale. The benches of Glen Eoy are an 

 example of them. The upper terrace is 1139 feet above tide-level; 

 the second, 1059; the third, 847 feet. This is one among many 

 cases that might be cited. As a general thing, elevated sea-beaches 

 occur on the coasts of regions whose interior is diversified with lake 

 and river terraces. When the facts are thoroughly studied, and the 

 exceptional cases traced to their true causes, there will probably be 

 found a system of phenomena which will prove that in Europe, as 

 in America, the Post-tertiary was a period of high-latitude oscil- 

 lations ; of an upward movement for the Glacial epoch ; a down- 

 ward — to so great a degree that the upper flats in the system were 

 flooded — for a following epoch, the Champlain ; and an upward 

 again to the present level in subsequent time. 



As an example of the peculiarities of the European continent, it 

 may be mentioned that the great Swiss glacier which buried all 

 Switzerland in ice probably belonged to the Terrace epoch ; for the 

 drift-stones and gravel traced to it overlie the alluvium of the coun- 

 try (see p. 577). 



LIFE OF THE POST-TERTIARY. 



It has been already stated that the plants and invertebrates (Mol- 

 lusks, etc.) of the Post-tertiary are, with a rare exception, living spe- 

 cies, while the Quadrupeds are nearly all extinct. 



The Drift epoch in America has afforded no organic relics except 

 half-fossilized wood. There is as yet no evidence of any quadrupeds 



