500 APPENDIX. pv 0 . 



Mountains, the winter, ameliorated by an open sea, is much milder than to 

 the eastward, and this difference is likely to be permanent : because the cur- 

 rent setting through Behring's Straits, and along the northern shores of the 

 continent, must continue to bring down annually large bodies of ice to the east 

 coast, to be detained there in the winding passages of a vast archipelago, and 

 in bays and inland seas for the summer. It may be proper to remark that 

 this accumulation of ice principally operates on the temperature of summer, 

 and has only a remote effect in increasing the cold of winter ; but that it is 

 upon the heat of the former season, that vegetation entirely depends in these 

 northern climates. 



Returning after this digression to Hayes River, we may state that the 

 boulders which obstruct its channels and line its banks, shew that there occur 

 in its river district rocks of the primitive class, as red granite, hornblende rock, 

 gneiss, and sienite ; of the transition class, as grey wacke ; and of the secondary 

 class, as red sandstone, belonging most probably to the new red sandstone 

 formation, under which we include the rothliegende and the variegated sand- 

 stone ; and two kinds of limestone, one having a bluish-grey colour, splintery 

 fracture, glimmering lustre, and translucent edges ; the other resembling marl, 

 and having, a yellowish-grey colour, an earthy fracture, and being dull and 

 opaque. 



The limestones appear to belong to the same or a similar formation with the 

 vast beds, to be hereafter mentioned in our account of the Saskatchawan and 

 Elk Rivers, and to have been brought down by the Shamattawa, on whose 

 banks it is said to form high cliffs. Indeed a low ridge of this sort of lime- 

 stone, about twenty miles wide, seems to run from the northward of Churchill 

 to Severn River, at the distance of thirty or forty miles from the sea-shore, and 

 nearly parallel to it *. 



The principal branch of Hayes River above the Shamattawa is named Steel 

 River. The banks of this stream have the same general character with those 

 of Hayes River, but their elevation is greater although they shelve more gra- 

 dually down to the water. Steel River is formed of two branches of nearly 

 equal size, named Fox and Hill Rivers. The former flows from the N. W., and 

 it is most probable that fragments of grey wacke, which we observed, on the 

 banks of Hayes River, came from that source, as we found no traces of the 



* See Mr. Auld, Transactions of the Geological Society, vol. v. p. 2. 



5 



