120 THE GLACIAL LAKE AGASSiZ. 



embraced the Laurentide highlands, James Bay, a portion of Hudson Bay, 

 and the western part of the Ai-chean region from Lakes Superior and 

 Winnipeg- to Great Slave and Great Bear lakes. From this large north- 

 eastern or Laurentide center of outflow the ice-sheet crept southward, 

 eastward, and northward to the limits of glaciation before noted. West- 

 ward the ice from this area outflowed, as I believe, to the limit of Archean 

 bowlders on or near the base of the Rocky Mountains, where I tind, from 

 Dr. Dawson's observations of the drift in Alberta and on the Peace River, 

 that it abutted against and was confluent with ice outflowing eastward and 

 southeastward from the Rocky ]\Iountains. The other area whence currents 

 of the ice-sheet flowed radially in every direction Avas the northern central 

 part of British Columbia; and the portions of the ice-sheet pouring outward 

 respectively from these two centers have been named by Dawson the 

 Laurentide and Cordilleran glaciers. Toward the south, west, and north- 

 west the Cordilleran outflow extended to the boundaries of our glaciated 

 area; but eastward, pouring- through passes of the Rocky Mountains, and 

 in the Peace River region probably overtopping the highest summits, which 

 there are only about 6,000 feet above the sea, the Cordilleran ice pushed 

 across a narrow belt adjoining the mountains to a maximum distance of 

 nearly a hundred miles, and there (on land about 2,500 feet above the sea) 

 became confluent with the Laurentide ice, the two united currents thence 

 passing in part to the south and in part to the north from the interior tract 

 where the confluent ice was thickest. 



JUNCTIOX OF THE LAURENTIDE AND CORDILLERAN DRIFT. 



Taking up the particular description of localities where the junction 

 of the Laurentide and Cordilleran drift has been observed, we may begin 

 at the international boundary and proceed northward. Laurentiau erratics 

 and di'ift are stated by Dawson to extend quite to the foot of the Rocky 

 Mountains near the forty -ninth parallel, and to occur between the forty- 

 ninth and fiftieth parallels, "stranded on the surface of moraines produced 

 by the large local glaciers of the Rocky Mountains."' 



In Montana, within 30 miles southward from the forty-ninth parallel, 

 Prof. G. E. Culver finds that ice was accumulated so thickly west of the 



' Trans., Roy. Soc. Canada, Vol. VIII, sec. 4, p. 57 ; Am. GiMilogist. Vol. VI, p. 162, Sept., 1890. 



