﻿1848. PYROGENOUS ROCKS. 147 



CHAP. V. 



PYROGENOUS ROCKS. — RATE OF THE CURRENT OF SLAVE RIVER. 



SALT RIVER AND SPRINGS. GEESE. GREAT SLAVE LAKE. 



DOMESTIC CATTLE. DEADMAN'S ISLANDS. HORN MOUN- 

 TAIN. HAY RIVER. ALLUVIAL LIGNITE BEDS. MACKEN- 

 ZIE'S RIVER. MARCELLUS SHALE. FORT SIMPSON. RIVER 



OF THE MOUNTAINS. — ROCKY MOUNTAINS. — SPURS. — ANIMALS. 

 AFFLUENTS OF THE MACKENZIE. — CHETA-UT-TINNE. 



No primitive rocks were seen on the route down 

 the Mackenzie, on this voyage, after leaving the 

 Portage of the Drowned; but in 1820, when we 

 crossed Great Slave Lake, near the 113th meridian, 

 we traced the western boundary of these rocks, from 

 near the mouth of Slave River, northwards by the 

 Rein-deer Islands to the north side of the lake, and 

 continued to travel within their limits up to Point 

 Lake in the 66th parallel. The western edge of 

 the formation was afterwards found at the north- 

 east and eastern arms of Great Bear Lake. 



The district intervening between the granite at 

 the Portage of the Drowned and the Salt River is 

 flat, with sandy terraces and slopes rising from the 

 river to the height of from twenty to eighty feet, 

 there being in some places two in others three or 

 more such terraces, while in others the river 



