340 DRIFT ICE AS AN ERODING 



Finally some of the most exposed situations show no signs 

 of abrasion by floating ice. Such are the Magdalen Islands and 

 Labrador, although in the latter place I have made special search 

 for such evidence. And though sea-borne ice may be counted 

 on as an eroding agent of moderate possibilities, as a factor in 

 the production of existing continental striations it can be allowed 

 only a very minor position, if indeed it cannot be altogether 

 eliminated. 



Transportation of Debris by Sea-borne Ice. 



It has been maintained by some of our foremost geologists, 

 that the Grand Banks of Newfoundland as well as the banks 

 off the Nova Scotia coast are chiefly of sub-Arctic origin. 

 Concerning this, questions like the following may arise in the 

 mind of an inquirer : If so, where are the moraines, the certain 

 results of glacial transportation from the provinces mentioned ? 

 What has become of all the debris carried from these provinces 

 when the river valleys were excavated, and when they stood at 

 a higher level than now ?* Also, is the quantity of material 

 brought south equal to the formation of such immense accumu- 

 lations ? 



I do not know that any very extended observations have 

 been made to find out to what extent this debris is being trans- 

 ported. Several observers in the polar regions have noticed 

 large quantities of loose stones and earthy matter on pan ice or 

 attached to icebergs, notably, Scoresby, Wilkes, and Sir John 

 Ross. Based on these statements, many investigators have given 

 great prominence to the transporting power of Arctic ice, and 

 write as if earth-laden ice was a common sight off the New- 

 foundland and Labrador coasts. But of those who have given 

 their time to the question, I know of none who have made 

 actual observation among the drift ice the basis of their theories. 

 Only by getting a fair idea of the quantity of debris remaining 

 on the ice toward the close of its long voyage, can a just opinion 

 be given of its capabilities as a transporting agent. 



1 See papers by W. H. Prestin Transactions of N. S. Institute of Science, 1891-92, 

 page 143 ; 1895-96, page 153. 



