NATURAL AREAS AND REGIONS 



125 



continent. 2 It has a total length of 

 nearly 300 mi., and is over 60 mi. wide 

 in its broadest part. Its shore lines 

 have remained unexplored, especially 

 as regards its eastern arm, until recent 

 years. Maps issued in 1923 by the Topo- 

 graphical Surveys branch show details 

 of this portion, excepting a few com- 

 paratively short stretches. 



The eastern part of the lake is much 

 deeper than the western part, and its 

 water is very clear, as is also that of the 

 northern arm. The main or western 

 part of the lake, which receives the 

 sediment-laden flood of Slave River, 

 never becomes so clear, although it is 

 fairly so at its outlet. Its southern 

 shores are very low; its northern borders 

 higher. It has few islands, and the rocks 

 on its shores are largely limestone. 



Great Slave Lake lies wholly within 

 the forested region, though some of its 

 eastern affluents drain large areas of 

 treeless country. Its southwestern 

 shores are well wooded, while the 

 northern shores, exposed for most of 

 the year to cold winds from the north 

 and watered by colder streams, are 

 poorly wooded. The soil conditions 

 are more favorable on the southern side 

 of the lake, exerting a marked influence 

 on the foresting. In general it divides 

 the southern heavy timber from the 

 northern stunted forest. 



On the Eastern Arm of the lake, how- 

 ever, the conditions in this respect are 

 more nearly uniform. Several streams, 

 the courses of some of which are practi- 

 cally unknown, enter this arm on the 

 southern side. Hoarfrost River, drain- 

 ing Walmsley Lake, and Lockhart 

 River, carrying the waters of Mackay, 

 Aylmer, Clinton-Golden, and Artillery 

 lakes, which lie almost wholly in the 

 Barren Grounds, fall into this arm near 

 its eastern extremity. The country 

 bordering its northern shore is rocky and 

 sparsely wooded, and contains a great 

 many lakes. 



The Northern Arm of Great Slave Lake 



* It is exceeded in size by Superior (31,500), Huron 

 (23,000), Michigan (22,300), and Great Bear (11,400). 

 IMcConnell.] 



lies along the junction of the primitive 

 and the newer formations. Its eastern 

 shore, therefore, is mainly composed of 

 granite, while its western border is of 

 limestone. Yellowknife River enters 

 this arm on its eastern side. At the head 

 of the Northern Arm, in an expansion 

 named Lake Marian, or Lac du Brochet, 

 Grandin River discharges its waters. 

 To the westward of the Northern Arm 

 and north of the main body of Great 

 Slave Lake lies a low, broad plateau, 

 dotted with many lakes and muskegs. 

 It contains no rivers of consequence and 

 is mainly rather thinly wooded, though 

 a number of large prairies occur in the 

 western part, north of the outlet of 

 Great Slave Lake. 



The country south of the main part of 

 Great Slave Lake is mainly flat and 

 swampy. Eagle Mountain, a low, iso- 

 lated range, lies a short distance south 

 of the extreme western end of the lake. 

 The principal stream is Hay River, 

 which rises close to the height of land 

 between the Nelson and the Peace, far 

 to the southwest. The region drained by 

 it is practically unknown, but is reported 

 to be low and swampy and mainly well 

 wooded, though it contains much grassy 

 prairie, Hay River being said to mark 

 the northern limit of this character of 

 country. 



Ice forms in the bays and along the 

 shores of Great Slave Lake in late 

 October, and the whole lake, though 

 kept open later by the violent winds, is 

 usually closed by mid-November. The 

 ice, which attains a thickness of 6 or 

 8 ft., usually breaks up in the main or 

 western part about the first of July, 

 but sometimes remains in the eastern 

 part until late July. 



Yellow Knife Preserve: An immense 

 area estimated to contain 70,000 sq. mi., 

 extending from Great Bear Lake and the 

 Coppermile River, south to Great Slave 

 Lake and Marten Lake, and thus in- 

 cluding much of the hunting grounds of 

 the Yellow Knife and the Dogrib In- 

 dians, is now closed to hunting by others 

 than natives. Its principal large game 

 are the moose and caribou. Formerly 



