Lawson.] 



The Upper Kern Basin . 



329 



occupied, for a time, by a long trunk glacier, which extended 

 down the canon as far as the mouth of Coyote Creek, and which 

 was fed by several tributary glaciers, heading in the cirques 

 of the High Mountain Zone, and flowing to it in the trenches, 

 which had previously been cut across the Chagoopa Plateau by 

 the tributary streams in their effort to keep pace with the sinking 

 of the Kern. In consequence of this episode in its history the 

 canon above Coyote Creek has the typical U-shape in cross 

 profile so characteristic of glaciated mountain valleys. (See 

 Plates 34b and 37 a). The bottom of this U-shaped portion of 

 the canon varies from less than half a mile to nearly a mile in 

 width and averages perhaps half a mile.* The distance between 

 the walls of the canon at its brink averages probably about a 

 mile, with but little variation from the average. In several 

 places along its length the walls are yet in the same condition as 

 when the ice vacated the canon, descending sheer to the floor, 

 smooth and fluted by glacial abrasion, and having little or no 

 talus at the foot. In other portions of the canon, and this is the 

 prevailing condition, the base of the cliffs is buried in talus, part 

 of which has evidently accumulated slowly by the gradual shed- 

 ding of fragments from the upper face, and part of which has 

 come down suddenly by the detachment of large masses from 

 above in the shape of rock-slides. Some of the blocks that have 

 thus fallen from the high part of the canon walls are finely scored 

 with glacial grooves. Besides these talus slopes there is, at the 

 mouth of every tributary canon, a deep alluvial cone furrowed 

 radially by stream channels, one or more of which are func- 

 tional, the others having been abandoned by the well known 

 shifting of the stream upon its cone. These cones are for the 

 most part composed of coarse boulders, only rudely rounded, 

 and even on the outer flanks of the cone the material is gravelly. 

 The boulders are frequently a yard or more in diameter, and over 

 many acres would average over a foot. The apex of these cones 

 is generally several hundred feet above the canon floor. These 

 cones are the product of streams which enter the canon far above 

 its bottom and which, in many cases, flow in glaciated trenches. 

 These trenches are fine examples of hanging valleys. As regards 



* Including the talus at the bottom of the cliffs. 



