Lawson.] 



The Upper Kern Hash). 



311 



peaks aud crests prevail these features are due to the intersection 

 of opposing canon and cirque slopes below the level of this gen- 

 eral surface, or to the intersection of such slopes with the steeper 

 slopes of the Summit Upland. Inasmuch, however, as the upper 

 limit of the second geomorphie, or High Valley, zone, the rear 

 of the Chagoopa Plateau, approaches the level of the Sub-summit 

 Plateau, by far the greater proportion of the High Mountain 

 Zone is the result of the sculpture of the mass whose surface was 

 the Summit Upland. 



Much of the precipitous ruggedness of the High Mountain 

 Zone in the northern three quarters of the basin is due, as will 

 appear more fully in the sequel, to the aggregation of glacial 

 cirques, which have eaten into the heart of the upland or plateau, 

 as the case may be. The intersection of opposing cirque walls 

 has in many cases reduced the summits to knife-edge crests or 

 lines of sharp pinnacles, which are often much below the level of 

 the original surface. From this point of view the region of the 

 dissected remnants of the upland and plateau might with 

 advantage be designated the zone of cirques. A fuller account 

 of this glacial sculpture is given in another part of this paper. 

 Whether we regard it as representing an ancient upland surface, 

 now left to us in mere remnants, or as a region of remarkable 

 sculpture, the Summit Upland with the subordinate Sub-summit 

 Plateau is a well defined geomorphie zone, which stands out in 

 bold and impressive contrast to the slopes below it. 



In the southern quarter of the basin, south of a line connecting 

 the southern limit of the High Sierra, on the summit crest, with 

 the corresponding termination of the Great Western Divide, 

 evidence of the former occupancy of the region by glaciers is 

 lacking. The general altitude is lower, and only in limited 

 areas rises to the level of the Sub-summit Plateau. The Summit 

 Upland portion of the high mountain zone is scarcely if at all 

 represented. The fierce assemblage of high, rugged, mountain 

 peaks and crests here gives way to the more familiar features of an 

 upland subdued by atmospheric and stream erosion. Between the 

 altitudes of 8,500 and 11,000 feet the drainage flows in wide, open, 

 V-shaped troughs of quite moderate grade separated by ridges 

 the crests of which slope toward the master streams. The stamp 



