QUATERNARY AGE. — GLACIAL PERIOD. 541 



(3.) This argument from fiords is corroborated by the facts con- 

 nected with the depth of river valleys, mentioned on the preceding 

 page ; and similar facts might be gathered from Europe. 



Further, there is evidence, as shown by F. H. Bradley, that waters 

 from Lake Michigan, in some era, cut a channel from the south end 

 of the lake southwestward to the Mississippi, following a course south 

 to the north line of Iroquois County, Illinois, and thence southwest 

 through Champaign and McLean counties, — the western margin of 

 the trough being well marked by buried escarpments, in some places 

 two hundred feet or more in height. Lake Erie, in like manner, has 

 been found, by G. K. Gilbert, to have discharged southwestward along 

 the course of the Maumee, and not by overflow merely, but by a strong 

 current which cut its trough. The under-sea course of the Hudson 

 River channel has been pointed out on page 423 ; and there is a simi- 

 lar one, though less perfect, for the Connecticut outside of Long Island 

 Sound. Again, General G. K. Warren has shown that Lake Winni- 

 peg once discharged southward, through the Minnesota River Chan- 

 nel, into the Mississippi, instead of into Hudson Bay as now. Such 

 facts are explained by him on the ground of a former elevation of the 

 continent to the north. With an elevation of but two hundred feet 

 along Southern New England, Long Island Sound would have been 

 for the most part a fresh-water channel, tributary to the prolonged 

 Connecticut. 



(4.) The Atlantic coast of North America, to the north of Cape 

 Cod, was higher than now during the Tertiary era, as is shown by the 

 presence of submerged Tertiary deposits off the coast (p. 490). 



(5.) The height required for the ice-surface, over the Canada water- 

 shed, in order that it may have sent a glacier over New England, 

 renders it probable, that part was acquired through an elevation of the 

 land. It may be that the Great Lakes were largely drained, in con- 

 sequence of the lifting at the north. 1 



The view that the land of Great Britain was above its present level, 

 when the glacier was formed, is urged by Lyell, Dawkins, Geikie, and 

 other British geologists. Erdmann, in his elaborate memoir on the 

 Quaternary of Sweden, observes that the fact of elevation is estab- 

 lished by the extent to which rocks were polished beneath the sea 

 level, and that the country was probably so much raised that a large 

 part of the Baltic was dry land. Spitzbergen, according to Nordens- 

 kiold, was so enlarged westward as to reach Scandinavia on the south 



1 The author's views on fiords and the subdivisions of the Quaternary (Post-tertiary) 

 were first published in the Amer. Jour. ScL, II. vii. 379, 1849, and xxii. 325, 346, 1856. 

 The subject is further reviewed and extended in III. i. 1, ii. 233, 1871, and v. 198, 1873, 

 ix. 312, x. 385, xiii. 79. 



