28 



NORTH AMERICAN FAUNA. 



[NO. 27. 



border is of limestone. Yellowknife Eiver, a considerable stream 

 which rises near the Coppermine and drains a number of lakes, 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. This stream has several branches, the main one 

 being Marten River, which forms the outlet of several large bodies of 

 Avater, of which Marten Lake is the largest. Grandin River proper 

 descends from a few small lakes near the low height of land to the 

 northward and receives from the northeast, above its junction with 

 Marten River, a small unexplored stream. The country drained by 

 these rivers is mainly rocky and poorly wooded. 



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 to the soutliAvard of the main part of Great Slave 

 Lake is mainly flat and swampy. Eagle Mountain, a low, isolated 

 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 south- 

 west. The country 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. To the eastward of 

 Hay River, Buffalo and Little Buffalo rivers enter the lake. So 

 far as known the country drained by them is similar to that bor- 

 dering Hay River. Slave River, the principal affluent of Great Slave 

 Lake, has already been described. 



The main facts in regard to the climate of Great Slave Lake may 

 be gathered by reference to the accompanying table of tempera- 

 tures taken at Hay River post, at the mouth of the river of that 

 name. 



Summaries of temperatures taken at Hay River, Great Slave Lake, during 



the year 1900. 



Month. 



Mean daily 

 maximum. 



Mean daily 



Extremes. 



Monthly 

 mean. 



minimum. 



Maximum. 



Minimum . 



January _ _ __ 



- 9.7 



- 7.1 

 15.6 

 47.8 

 56.4 

 67.3 

 72.1 

 68.8 

 58.5 

 40.3 

 15.2 



- 2.6 



-26.9 

 -29.5 

 -13.5 

 22.9 

 34.7 

 43.5 

 49.3 

 46.9 

 38.1 

 22.6 

 — 2.5 

 -10.8 



5.0 

 6.0 

 46.0 

 68.0 

 72.0 

 79.0 

 85.0 

 83.0 

 76.0 

 61.0 

 32.0 

 24.0 



-47.0 

 -44.0 

 -44.0 

 5.0 

 20.0 

 31.0 

 42.0 

 32. 0' 

 28.0' 

 8.0 

 -28.0 

 -40.0 



-18.3 

 -18.3 

 1.0 

 .35.3 

 45.6 

 55,4 

 60.7 

 57.9 

 48.3 

 31.5 

 6.3 

 - 4.1 



February _ 



March _ 



April _ _ 



May _ - _ 



June ______ 



July 



August 



September 



October _ _____ 



November 



December __ 





Year__ __ . _ _ _ 







85.0 



-47.0 



24.9 



