Lawson.] 



The Upper Kern Basin. 



30] 



veneer upon plateau surfaces which represent a comparatively 

 late stage in the evolution of the geomorphy of the region. In 

 the later stages of that evolution they have suffered the same 

 dissection as the plateaux, and appear now only as remnants. 

 Where they remain, however, they greatly accentuate the flatness 

 of the plateau, and this is their chief contribution to the 

 general morphogenic process. 



From the foregoing statement of the petrographic character- 

 istics of the terranes which underlie the basin of the Upper 

 Kern, it will be evident that there are certain diversities in the 

 rocks of the region which account in some measure at least for 

 the inequalities of the relief in so far as these are due to atmos- 

 pheric erosion. When, however, we ask what part these varying 

 petrographic characteristics have played in determining the 

 drainage scheme of the basin, there is no answer forthcoming. 

 Nothing in the petrography of the terranes affords us any clue, 

 for example, to the arrow-like course and meridional trend of the 

 master stream of the basin, and much less does it afford an 

 explanation of the remarkable contrasts in the slopes of the 

 basin. 



The Roof of the Granite. — It has been stated in the foregoing 

 discussion that, in various parts of the granitic region of the 

 southern Sierra Nevada, there are outlying areas of pre-granitic 

 stratified terranes, remnants of formations which formed the 

 outer crust of the earth in this region, at the time of its invasion 

 by the vast Sierran batholith or batholiths. These formations 

 may be safely assumed to have originally arched over this batho- 

 lith as a covering shell. The surface of contact between the 

 granite and the overlying rocks was clearly a very uneven one. 

 This is shown, not only by the relation of these remnants to the 

 granite, but also by the spacial relations of the granite and the 

 rocks invaded by it in the northern Sierra Nevada, where the 

 relative areas of the two classes of rocks are revei-sed and the 

 granite appears as inliers in the stratified, though often highly 

 metamorphosed terranes. It has been made clear farther that, 

 in the Mineral King belt of sedimentary rocks, which lies imme- 

 diately to the west of the Upper Kern Basin, we have such a 

 remnant of the roof of the batholith which has been sunk deeply 



