A "CORDILLERAN GLACIER" IN BRITISH COLUMBIA 59 



As seen from the river the banks rise to a horizontal plain, which 

 extends eastward and westward for an indefinite distance. Here 

 and there as many as five different terraces might be counted one 

 above the other on the insides of some of the bends, but altogether 

 the valley has a very juvenile appearance. It is clearly pre- 

 glacial, for bowlder clay may be seen resting on its sloping sides 

 and lying on some of its terraces. In some places, where it has 

 been* partly filled by bowlder clay during the glacial period, the 

 channel has been re-excavated to about its previous depth. Near 

 the top of its banks beds of bowlder clay are here and there inter- 

 stratified with layers of sand, some of which have been crumpled, 

 giving evidence that glaciers from the mountains to the east or 

 west descended into lakes which then existed in the bottom of the 

 valley, and squeezed up the beds of gravel and sand that had just 

 been deposited in those lakes. 



Above Cottonwood Canyon the valley maintains the same 

 general character as below it, with steep banks rising to the adjoin- 

 ing plain, but in addition to the Miocene(?) conglomerates, etc., 

 schistose rocks, similar to the Cariboo schists, outcrop here and 

 there, while at still other places the banks are composed of strati- 

 fied sand or clay of glacial or postglacial age. 



It is impossible to imagine such a winding, gorgelike valley as 

 this of the Fraser River, with its short curves, and with the rela- 

 tively sharp angles where its steep sides meet the surrounding 

 plain, continuing to exist after a great continental glacier many 

 thousands of feet in thickness has passed along it. Its appearance 

 is quite different from that of such of the British Columbia valleys 

 as have undoubtedly been occupied by great glaciers. On the 

 contrary it has a strong topographic resemblance to the Yukon 

 Valley near Dawson City, where the river flows through an unglaci- 

 ated part of the Yukon Plateau, which is a northern continuation 

 of the interior plateau of British Columbia. Here glaciers for- 

 merly descended from the Coast Range of mountains eastward to 

 the interior plateau, and others descended from the Rocky Moun- 

 tain range westward to the same plateau, but as they did not 

 meet they left an unglaciated area between them. In the Fraser 

 Valley glaciers also descended from the mountains to the east 



