﻿176 BANKS OF THE MACKENZIE. Jult, 



are fourteen or fifteen ranges of hills, and that 

 when they are viewed from the summit of a peak, 

 the mountain tops appear to be crowded together 

 in great confusion, like a sea of conical billows. 

 My informants could not tell me whether granite, 

 clay-slate, or trap rocks entered into their compo- 

 sition or not ; but it is probable that such is the case, 

 as we know it to be in more southern latitudes. I 

 received specimens of semi-opal, plumbago, and 

 specular iron, gathered on one of the ridges. The 

 more westerly ranges have obtained from the 

 traders the name of the Peak Mountains. 



On the Mackenzie, a shaly formation makes the 

 chief part of the banks, and also much of the undu- 

 lating valleys between the elevated spurs. It is 

 based on horizontal beds of limestone, and in 

 some places of sandstone, which abut against the 

 inclined strata of the lofty wall-like ridges, or rest 

 partially on their edges. Covering the shaly beds, 

 there exists in many places a deposit of sand, some- 

 times cohering so as to form a friable sandstone ; 

 and where a good section of the bank occurs, a 

 capping of gravel and boulders, of various thickness, 

 is seen crowning the whole. The shale crumbles 

 readily, and often takes fire spontaneously, occasion- 

 ing the ruin of the bank, so that it is only by the 

 encroachments of the river carrying away the debris 

 that the true structure is revealed. The boulders 



