SOME ANIMALS OF YUKON TERRITORY 309 



Tanana Rivers east of longitude 146 degrees. There are 

 no other exceptions. 



Throughout the Mackenzie Rockies, within the Mac- 

 kenzie water-shed south farther than latitude 62 degrees, 

 sheep are pure white. 



In the Yukon Territory, all sheep north of latitude 

 66 degrees, south of latitude 62 degrees, and west of 

 longitude 136 degrees, are pure white. Pure white sheep 

 greatly preponderate west of the Lewes and Yukon 

 Rivers. 



The sheep south and east of the Stikine River in 

 British Columbia are uniformly dark with occasional 

 exceptions. 



From the Sheslay River region north of the Stikine 

 River, north along the uninterrupted area of travel through 

 the Cassiar ranges and the Pelly River region, there is a 

 more general uniformity of color, more lighter sheep 

 occurring along the Pelly River. 



In the Ogilvie Rockies the tendency toward white pre- 

 vails increasingly toward the west and north. 



Throughout the Selwyn Rockies, and in the region 

 between the Sheslay River district and the Lewes River, 

 the color of the sheep is extremely variable. 



Generally, variation in color occurs in some of the 

 regions west of the Yukon water-shed, east of longi- 

 tude 136 degrees, between latitudes 58 degrees and 65 

 degrees. 



The facts indicate that, within the areas of color vari- 

 ation, sheep inhabiting the continuous unbroken ranges 

 have a tendency toward uniform colors, while those in- 



