34 



NORTH AMERICAN FAUNA. 



[NO. 27. 



discharges its muddy waters. As far as known the countr}^ bordering, 

 this part of the Mackenzie on both sides is rolling, well watered, 

 and fairly Avell wooded. A few miles below Arctic Red River the 

 high banks of the Mackenzie gradually l)ecome lower and the river 

 spreads ont into the delta. Peel River, the large-t tributary of the 

 Mackenzie except the Liard. also enters the head of the delta by 

 several mouths. 



Peel River is fed by a number of large tributaries, which rise 

 in the mountains some 400 miles to the southward of its mouth. The 

 main river has been ascended to near its head, but the country drained 

 by it is very imperfectly known. 



The" Mackenzie Delta occupies a triangular area nearly 100 miles 

 in length and 50 miles broad at its widest part. The various branches 

 inclose several large islands and a multitude of smaller ones. At 

 the head of the delta these islands are well wooded vrith spruce and 

 balsam poplar. Lower down these trees give way to willoAvs. which 

 continue to the sea. To the westward of the delta lie^ a range of 

 high hills, the northern extremity of the Rocky ^Mountains. They 

 rise to a height of from 1.200 to 1.500 feet,, and their lower slopes 

 only are wooded. The Caribou Mountains, apparently a continuation 

 of the ridge which crosses the Mackenzie at the Lower Ramparts, 

 lie to the eastward of the delta. They rise to a height of 700 to 800 

 feet and are less rugged than the mountains west of the delta. 



The climate of the Mackenzie Valley is fairly indicated by the 

 tables of temperature whicii follow. They were taken in 1900, which 

 seems to have l)een a year of about average condition^;. 



Summaries of temperatures talxen at Fort Simpson. j.IarL-citzi' . during the year 



1900. 



Month. 



Mean daily 

 maximum. 



Mean daily 

 minimum. 



Extremes. 

 Maximum . Mi::ima:n . 



Monthly 

 mean. 



Januarj' __ _ _ 



-16.2 



-33.5 



5.0 



-51.0 



-24.8 



Fe'iruary 



- 9.2 



-33.5 



14.0 



—50.5 



-21.4 



3^ir'h 



12.8 



-17.4 



39.0 



-50.0 



- 2.3 



April _ 



41.2 



17.8 



60.0 



5.0 



29.5 



May 



52.6 



35.2 



66.0 



27.0 



43.9 



June 



69.3 



45.3 



80.0 



27.0 



57.3 



July 



69.-1 



45.7 



79.5 



31.5 



57.6 



August 

 Septe-Tiber 



65.0 



44.1 



78.0 



27.0 



54.5 



56.8 



34.7 



71.0 



23.0 



4.-. 7 



October _ 



29.0 



19.2 



40.0 



3.0 



24.1 



iVovember 



5.1 



- 8.7 



23.0 



-29.0 



- 1.7 



December 



. - 7.3 



-20.1 



13.0 



—18.0 



-13.7 



Year _ 









80.0 



-51.0 



20.7 



1 





The temperatures of the extreme upper Mackenzie are undoubt- 

 edly slightly lower than those recorded for Fort Simpson, but com- 

 parable data are not at hand. 



For purposes of comparison corresponding figures for points in 

 the valley of the lower Mackenzie and for Herschel Island follow. 



