﻿1861.] 



HECTOR ROCKY MOUNTAINS, ETC. 



403 



ties of Spruce-fir for the most part, with, dense underwood ; but on 

 passing south of the slight bend of the Columbia, the tread of the ter- 

 race-steps commences to expand into wide level plains, dotted with a 

 forest of the sturdy Pinus ponderosa or the gigantic Lar'ioc occiden- 

 talis, both of which are trees that find their maximum in Southern 

 Oregon. The outlines of the terraces still preserve the same extreme 

 formality and steepness of slope, but on their level surface a rider can 

 gallop in almost any direction, so free is the forest from underwood. 

 Sometimes the trees are entirely wanting, leaving great tracts of open 

 plain embosomed in the mountains, forming the camping-grounds of 

 the Kootanie and Flat-head Indians, on which they raise the large 

 bands of horses for which they are famous amongst all other Indians, 

 the dry soil and nutritious bunch-grass producing a breed of superior 

 hardihood and swiftness. 



In descending the Kootanie River from the Tobaco Plains * to 

 Colvile the country is rugged in the extreme, and these terraces are 

 met with wherever they have been sheltered from recent erosion in 

 valleys of unusual width or in recesses of the more narrow ones. 

 On reaching the belt of country where schistose and metamorphic 

 rocks prevail, the pebbles are often composed of greenstone, quartz, 

 and the other vein-rocks of the strata which they overlie. On reaching 

 the lower part of the country near Colvile, the terraces are still found 

 in all the valleys, not only at moderate elevations but also high up in 

 the mountains. Thus the Columbia at Fort Colvile, in latitude 48° 

 34', is 1000 feet above the sea, and terrace-deposits were observed on 

 the sides of the valley at least 1200 feet above the river-level. 



The great Columbian Desert and the Spokane Plain are both 

 covered with the same deposits of shingle, resting, in the former case, 

 on the great lava-floes, and, in the latter, on granite and metamorphic 

 rocks. The Spokane Plain, which is of comparatively limited extent, 

 has its margin beautifully terraced, repeating on a grand scale the 

 same phenomena as may be observed on the shore-line of a shallow 

 lake after the summer-drought. At old "Walla Walla, where the 

 Columbia River passes from a wide and flat sandy desert to break 

 through the profound rocky canon of the Cascade Range, the whole 

 country is covered with light blown sand, which renders it almost 

 uninhabitable, being swept in clouds by the high gales that constantly 

 blow either up or down the river through this wonderful chasm. 

 Here in an ancient lake-bottom have been found the remains of a 

 Mastodon by some American explorers. 



To the west of the Cascade range of mountains along the Pacific 

 coast, terraces of shingle prevail as in the interior. Also on Vancouver 

 Island they were observed near Nanaimo. Near Fraser River and 

 Puget Sound they are very well marked, and at the latter place occur 

 the " Mound-prairies," which, however, I only know of by report. 

 These are level surfaces of terraces free from forest, and covered with 

 lines of conical mounds, 10 to 20 feet high, said to be formed of 



* The term " Tobaco Plain" should proper 1 y be only applied to a little plot 

 near the Kootanie Trading Post, but we have thought it advisable to extend the 

 name to all the large plains along the Kootanie River near lat. 49° N. 



