8 DE. G. M. DAWSON ON MAMMOTH -EEMAINS [Feb. 1 894, 



changes equally affected the northern region here particularly treated 

 of ; for it is not only very distant from the localities which have so 

 far been specially studied, but the physical features of the Cordilleran 

 belt become diffuse and ill-marked to the north, and such mountain- 

 ridges as remain assume new trends. It may, however, be taken 

 for granted that this region shared to some extent in these great 

 movements of elevation and depression, and as the very existence of 

 the ' ground-ice ' shows that the area where it is found has not 

 since the date of its formation been materially lower than at present, 

 it may reasonably be argued that it dates from a period approaching 

 the conclusion of the series of changes in level, or subsequent to the 

 last well-marked epoch of depression of the land. 



Thus, without entering into any details respecting the sequence 

 of these great earth-movements in the Cordilleran region of British 

 Columbia, 1 it may be stated as probable that the uprising of the 

 land which led to the accumulation of the ' ground-ice ' was co- 

 incident with the second (and latest) epoch of maximum glaciation, 

 which was followed by an important subsidence in British Columbia. 



Discussion. 



The Peesident said that many interesting points had been brought 

 forward by the Author. The differentiation of the glaciated from 

 the unglaciated area, and the clear recognition of a north-western 

 as well as a south-eastern boundary to the Cordilleran ice-mass, 

 struck him as being of great importance. 



Sir Heney Howoeth remarked upon the long and careful survey 

 of N.W. America which has been made by the Author, and upon 

 the value of the conclusions to which he has come : firstly, in regard 

 to the absence of ancient glaciation in Alaska and its borders ; 

 secondly, in regard to the existence of a great glacier in the 

 Cordilleras, whose products are quite independent of and have 

 nothing to do with the Laurentian drift ; and thirdly, in regard to 

 the distribution of the Mammoth. It was a new fact to him, and 

 one of great importance, that Mammoth-remains had occurred in 

 Unalashka and the Pribilof Islands in Bering Sea, proving that 

 in the Mammoth age there was a land-bridge here, as many 

 inquirers had argued. It would be very interesting to have the 

 western frontier defined, where the Mammoth-remains cease to be 

 found. It would also be very interesting to know how far south on 

 the west of the Cordilleras the true Mammoth, as distinguished from 

 Elephas Columbi, has occurred. 



Regarding one conclusion of Dr. Dawson's, the speaker could not 

 agree with his friend, namely, about the age of the strata of ice 

 sometimes found under the Mammoth-beds in Alaska as they have 

 been found in Siberia. The speaker was of opinion that this ice has 

 accumulated since the beds were laid down, and was not there when 

 the Mammoth roamed about in the forests where he and his coni- 



1 For a disoussion of which see Trans. Royal Soc. Canada, vol. viii. (1890 ) 

 sect. iy. pp. 40-55. 



