442 ARTHUR BEVAN 



LOCATION AND EXTENT OF THE RANGE 



The Beartooth Mountains are in southern Montana and north- 

 western Wyoming, where they form the front range of the Rocky 

 Mountains. The range has the approximate form of a broad, 

 much elongated, sHghtly curved oval which extends southeasterly 

 from Yellowstone Valley above Livingston to the canyon of the 

 Clark Fork of Yellowstone River, about 30 miles northwest of 

 Cody, Wyoming (Fig. i). It is about 80 miles long and has a 

 maximum width of about 30 miles south of its central portion, 

 northeast of the northeast corner of Yellowstone Park. 



The boundary between the range and the Great Plains is sharply 

 marked (Figs. 2 and 3) but the boundary on the southwest is much 

 less definite. South of the state line the Clark Fork is taken com- 

 monly as the line of demarcation between the Beartooth Mountains 

 and the Absaroka Range to the west. In Montana the two ranges 

 merge more or less, which makes it difficult to draw a sharp natural 

 boundary between them. For this discussion the boundary is taken 

 mainly along the divide between the streams that flow south and 

 west to Yellowstone River and those that pursue a northerly course 

 across the greater portion of the Beartooth Mountains to the same 

 river far beyond the front of the range. Inasmuch as this boundary 

 roughly follows the structural limits of the range, it is less arbitrarily 

 chosen than may appear from this statement. 



The range lies wholly within the drainage system of Yellowstone 

 River. With the exception of Soda Butte Creek and a few other 

 small creeks that flow into the northeastern part of Yellowstone 

 Park, all of the streams flow northeasterly from the plains-ward 

 front of the range across the bordering plains for many miles before 

 uniting with the trunk stream. The main streams are permanent, 

 even in seasons of excessive drought, as they receive an abundant 

 and constant water supply from numerous perpetual snow fields, 

 several small glaciers, and a multitude of lakes that are scattered 

 throughout the range. 



