﻿1361.] 



HECTOR — HOCK? MOUNTAINS, ETC. 



401 



seams of coal. Within, the mountains the terraces expand so as to 

 form level prairies along the North Saskatchewan, of which the 

 Kootanie Plain is the principal. It is many miles in extent and 

 composed of shingle and incoherent sand, the widest terrace being 

 100 feet above the river. The river is, however, skirted by terraces 

 at still higher levels, especially on the south or right side of the 

 valley. Above Pine Point the calcareous matter of these terrace - 

 deposits so increases as to replace altogether the pebbles, and they 

 are often composed of fine gritty calcareous mud of glistening white- 

 ness. If followed into the higher valleys, they become confused with 

 the detritus of ancient glacier-moraines, which, however, are easily 

 distinguished by the angular blocks which they contain. 



On the Athabasca River, at fifteen miles from the mountains in 

 a direct line, the terraces were found at 15, 100, 210, and 370 feet 

 above the river-level. Within the mountains, this valley, which is 

 more dilated than even that of the North Saskatchewan, has also the 

 terraces better developed than I have elsewhere observed them on 

 the east side of the chain. The river moreover dilates into extensive 

 lakes at different points of its course, and there the rearrangement of 

 the material of the terraces is seen to be going on ; the water sepa- 

 rating the calcareous mud from the pebbles, while the winds, which 

 are extremely violent in this valley, sift out the fine sand and pile it 

 in tracts of sand-dunes which cover large areas. 



The terraces may be considered as ranging on the east side of the 

 Rocky Mountains from 3500 to 4500 feet above the sea. Wherever 

 they prevail they support a growth of a peculiar sturdy pine which, 

 in common with the Banksian Pine, is known to the Hudson Bay 

 Company's hunters as the Cypres *. 



Often the surface of a terrace is quite free from timber, the trees 

 being easily thrown out of the loose gravelly soil, and then it is ge- 

 nerally clothed with " bunch-grass f ," which at once catches the eye 

 as different from the grasses of the eastern plains. The country occu- 

 pied by the terraces is easily passed through, as the forests are there 

 free from underwood, and the only obstacle to the traveller arises 

 from his having so often to make a steep descent to the base of the 

 deposit, which is cut through by every little stream, and then to 

 climb again the opposite bank. When passing along the side of a 

 valley, the numerous cross gulleys due to this cause would render the 

 construction of a road a very difficult matter, although nothing could 

 be firmer or more level than the surfaces of the terraces themselves. 

 This remark applies equally to the valleys on the west side of the 

 Rocky Mountains, where the terrace-deposits have a much greater- 

 development. 



Terraces of the Western Slope. — All the valleys between the Rocky 

 Mountains and the Pacific coast lower than 4000 feet above the sea 



* This pine is allied to the Pinus inops of the Atlantic bord and to the P. con-, 

 torta of the Pacific, and yet has distinctive characters from either. It has been 

 proposed to call it Pinus Saskatchewensis, Hooker. 



f Festucce of various species. The grass on the eastern plains consists of varie- 

 ties of Ckondrosium (Blodget's 'Climatology of the United States,' p. 451). 



