COMPAEISOiT WITH THE GEEEXLAND IGESHEET. 123 



amount to full and convincing proof that the ice of the Laurentide and 

 Cordilleran areas of outflow became confluent, and at its culmination 

 stretched as one continuous ice-sheet from the Atlantic to the Pacific, 

 enveloping the northern portion of the Rocky Mountains in then- compara- 

 tively low development within the basin of the Mackenzie and Peace 

 rivers, and overspreading the whole of the Dominion of Canada soiith- 

 ward, except the highest parts of the Rocky, Selkirk, and Coast ranges. 



COMPARISON WITH THE PRESENT ICE-SHEET OF GREENLAND. 



An ice-sheet similar to that of North America in the Glacial period 

 now covers the Antarctic lands, and another is spread over the interior of 

 Greenland. The latter has been so far explored within the past ten years 

 by Noi'denskjold, Peary, and Nansen as to give us a knowledge of its 

 slopes and the altitude of its surface, with which the ancient ice-sheets of 

 North America and Europe may be most instructively compared. 



The first long journey on the Greenland ice-sheet was accomplished 

 by Nordenskjold in 1883, going eastward from Aulatsivik Fjord, close south 

 of Disco Bay, near latitude 68° 20' north. At a distance of about 73 

 miles from the head of this fjord and edge of the inland ice Nordenskjold 

 reached an altitude of 4,950 feet; and at a probable distance of 45 04- 50 

 miles farther, crossed by Lapps on the peculiar snowshoes called "ski," the 

 barometers indicated a height of 6,386 feet. The average ascent of the ice 

 surface here in the first 73 miles, including the more rapid rise near the 

 margin, is about 68 feet per mile, or slightly less than three-quarters of a 

 degree; but in the next 45 miles of estimated distance it is reduced to 32 

 feet per mile, or about a third of a degree.^ 



A second important journey on the inland ice of Greenland was by 

 Lieut. R. E. Peary and Christian Maigaard in 1886, going east from the 

 head of Pakitsok Fjord, on the northeast jsart of Disco Bay, in latitude 

 69° 30' north. These explorers advanced to an estimated distance of 

 about 100 miles from the edge of the ice, attaining an altitude of about 

 7,500 feet- 



'Science, Vol. II, pp. 732-738, with map, Dec. 7, 1883. For the more accurate final computatious 

 and estimates of distances and altitudes, see The First Crossing of Greenland, by F. Nauseu, 1890, Vol. 

 I, pp. 494-499, with map ; Vol. II, pp. 467, 468. 



•Bulletin of the American Geographical Society, Vol. XIX, 1887. pp. 261-280. 



