Lawson.] 



The Upper Kern Bo sin. 



2! 1 7 



below the Kern Lakes is more than a coincidence, an assumption 

 which the writer does not feel warranted in making. 



Except for the occurrence of the gabbros and the lamprophyric 

 dykes, the summary account given above of the granitic rocks of 

 Kern Canon would apply fairly well to all the granite country 

 lying to the west of Kern River in so far as it came under the 

 writer's observation. In the high country to the east of 

 Kern River, however, particularly in approaching the summit 

 crest, the granite has quite a different facies. The rock here is 

 uniformly a light colored biotite- granite with a splendidly devel- 

 oped porphyritic structure. The porphyritic crystals are huge 

 orthoclases with perfect crystal boundaries. These are quite 

 frequently three inches in length and average two inches over 

 wide areas. They usually contain inclusions of biotite and 

 hornblende, disposed in rude rectangular zones parallel to the 

 planes of growth of the crystal. In this granite there appear to 

 be no local basic facies, and the inclusions which are so abundant 

 in the granite of the Kern and the country to the west are almost 

 or wholly absent. Dykes of coarse pegmatite are fairly common ; 

 and dykes, often of large size, of gray and pinkish aplite are in 

 places very abundant. 



Disintegration. — These purely petrographical differences in 

 the prevailing rock of the region are mentioned for the purpose 

 of indicating possibilities in differential resistance to erosion and 

 so aiding us in coming to an understanding of the inequalities of 

 the relief. That such differential resistance to the attack of 

 atmospheric agencies actually does characterize the granite, even 

 where no petrographical distinction can be drawn, is amply 

 witnessed by the heavy mantle of disintegration products which 

 occurs upon many of the unglaeiated slopes, sometimes as a 

 coarse, loose sand into which one sinks deeply in climbing, and 

 sometimes as an encumbrance of loose blocks of large dimen- 

 sions. The disintegration which yields the coarse granitic sand 

 is well exemplified on the trail between Farewell Gap and Coyote 

 Pass, on the upper waters of Coyote and Volcano Creeks, and along 

 the trail between Mt. Guyot and Crab-tree Meadows. On the 

 steep upper slopes of Sawtooth Peak and Mt. Whitney this sand 

 is very abundant, but is in sxich situations admixed with angular 



