QUATERNARY AGE. — CHAMPLAIN PERIOD. 543 



2. CHAMPLAIN PERIOD. 

 1. American. 



The Champlain period is so named from the occurrence of beds 

 of the period on the borders of Lake Champlain. 



L General Course of Events. 



The earlier part of the Champlain period was the era of the 

 melting of the great glacier, and of most local glaciers ; and therefore 

 the era of immense floods along the valleys ; of many and great lakes ; 

 and of the deposition of the sand and gravel of the glacier, except 

 the relatively small part which had been earlier dropped. While the 

 Glacial period was eminently a period of abrasion and of valley- 

 erosion, and of the gathering and transportation of earth and stones, 

 and also of some deposition along the course of the glacier, and much 

 at its terminus, the Champlain was the era of the general depo- 

 sition of this earth and stones, and the further distribution of it by 

 inland waters in the excavated valleys and lake-basins, and along sea- 

 borders. 



Facts demonstrate, moreover, that the period was not only one of 

 lower level than the present, but, further, that the amount of depres- 

 sion increased northward, so that the beds of rivers flowing south- 

 ward often had diminished slope in Champlain time, and the waters a 

 slackened flow, with, consequently, many expansions into lakes along 

 their course ; and that their exit to the sea was often by long and 

 wide estuaries. 



The Champlain period, or era of depression, includes two sub- 

 divisions : — 



1st. The Diluvian epoch, or that of the depositions from the melting 

 glacier, which depositions began when the melting had far advanced 

 (the earth and stones having been in the lower portion of the glacier, 

 and the melting having been general over its surface), and which 

 continued — probably with some interruptions — until the melting 

 had ended. Direct evidence of the final flood is contained in the 

 deposits, as explained beyond, on page 548. 



2d. The Alluvian epoch, or the part of the era of depression after 

 the melting had ended, characterized by depositions of a more quiet 

 character. 



II. Rocks : kinds and distribution. 



1. Kinds of deposits. — The deposits of the Diluvian division of 

 the Champlain period are of the following kinds : (1) those that were 



