GEOLOGY OF THE BEARTOOTH MOUNTAINS, MONTANA 447 



The summit plateau. — The axial portion of the range is character- 

 ized by two distinctly opposing features: its extreme ruggedness, 

 and the flattish summits of many of the dominant peaks (Fig. 5). 

 The highest peaks and ridges of this rugged district in the south- 

 central part of the range exhibit remarkably even-crested summits 

 when viewed from any direction. The most extensive remnant of 



Fig. 5. — Remnants of the summit peneplain along the main divide at the head of 

 Rock Creek. Elevation of the even crests is about 12,400 feet. Looking southwest 

 from Silver Run Plateau. 



the, summit plateau, which is called the Beartooth Plateau/ exists 

 just north of the Wyoming boundary. It is a narrow, deeply 

 notched plateau with an area of several square miles, which coin- 

 cides with the axis of the range for about 12 miles (Fig. 2). Its rim 

 almost everywhere overlooks very steep slopes or sheer precipices, 

 most of which are from 1,000 to more than 1,500 feet high. The 



' The name Beartooth Plateau has been used by some to mean the sub-summit 

 plateau along the eastern front of the range, or the glaciated plateau on the south- 

 western slope. The writer follows the usage of the term on the published topographic 

 map of the Beartooth National Forest, where the name is restricted to the summit 

 plateau. 



