Trans. N. Y. Ac. Set. 156 June 4, 



of 500 feet or more, and its lower end was only 5,500 feet above the sea. 



The glaciation of the Uinta range has been graphically described by 

 King, who says that the ancient glaciers of these mountains occupied a 

 greater area than all those of the Alps. 



In the Rocky Mountain belt the signs of glaciers abound, from the 

 northern part of New Mexico through Colorado, and along the great 

 divide in Wyoming, Montana and Idaho. 



In these Western mountain ranges the glaciers were far more ex- 

 tensive than any now to be found on the earth's surface, unless on the 

 Antarctic continent or Greenland. The record they have left consists 

 of planed, grooved and striated rocks, covering immense areas, lateral 

 and terminal moraines, moraine lakes, etc., etc., — a record which is 

 as legible and reliable as any printed page. 



In the country east of the Mississippi, the evidence of ancient glacia- 

 tion is even more widespread and impressive than in the Far West. 

 All the surface rocks of Canada, of New England, of New York, and 

 the greater part of Ohio, Indiana, Illinois and Wisconsin, bear marks of 

 ice-action, and are generally covered with a sheet of drift material 

 which has been carried by glaciers from the north southward, often 

 many hundred miles. This glaciated and drift-covered area extends 

 from Maine and Massachusetts westward in a belt parallel with the 

 arch of the Canadian Highlands, 500 miles wide and more than 2,000 

 miles long. Its extension northward from the head-waters of the 

 Mississippi has not been traced further than Lake Winnipeg, where it 

 was studied by Hind ; but there are good reasons for believing that it 

 extends to the Arctic Ocean, and that the great lakes of the North, like 

 those of the St. Lawrence chain (Superior, Huron, Michigan, etc.), are 

 old river-valleys scooped out and- modified by glaciers. Above the 

 Canadian line, George M. Dawson reports that the glacial drift from 

 the Canadian Highlands extends westward till it meets that which 

 was spread eastward from the Rocky Mountain belt. 



From the facts already gathered, it is a justifiable inference that 

 fully one-half of the continent of Noith America, north of the 36th 

 parallel, was at one time covered with ice or perpetual snow, and, so 

 far as we can now judge, the glaciation of all the areas enumerated 

 was synchronous, and that it occurred at the same time with the great 

 expansion of the glaciers of Europe. 



Some writers have attempted to prove that a large part of the glacial 

 phenomena described are really the work of icebergs, and the conse- 

 quences of a great continental subsidence ; but no man who has studied 

 the inscriptions made by glaciers will hold to such a theory, when he 

 has traversed much of the glaciated areas east or west of the Missis- 

 sippi. 



