340 



University of California. 



[Vol. 3. 



apply the hypothesis of rifting to explain the kernbuts, viz: that 

 it could not be confined to these, but involved the greater part of 

 the canon of the Upper Kern, seems not insuperable. A consid- 

 eration of various features of the Upper Kern Canon indicates 

 that the process of crustal rifting played a part in the genesis of 

 the canon, or, at least, that there are many features of the canon 

 that are in harmony with that notion. 



Application oj Rift Hypothesis to Kernbuts. — This conclusion 

 not only clears the way for the application of the hypothesis of 

 rifting to the kernbuts but strongly supports the suggestion. If 

 now the kernbuts are due in any way to the slipping of massive 

 wedges into an opening chasm along a rift line, they are either 

 local slips, or they are remnants of much longer slips which 

 locally have not sunk as far as the main mass. Both of these 

 possibilities demand consideration. If they are local slips, then 

 we are confronted with the embarrassing question as to what 

 happened in the intervals between them? These intervals should 

 have the normal cross profile of a V-shaped erosion canon, plus 

 any aggradation effects due to damming. In that portion of the 

 canon above the limit of glaciation we may provisionally regard 

 the breadth of the canon, at its bottom, and the verticality of its 

 walls, as due to the modification of a V-shaped canon by ice 

 action. But the canon below the main terminal moraine is just as 

 wide at the bottom, and has just as vertical walls at several places, 

 as it has above the moraine. The Avidth of the canon for a mile 

 above Coyote Creek for example, cannot be referred to glacial 

 modification. The stream ward face of Tower Rock is 2150 feet 

 as sheer above the stream as any part of the glaciated portion of 

 the canon. Immediately below the kernbut to the south of 

 Lower Lake the canon widens out and has a very high and very 

 sheer west wall (see Plate 38 a.), although the opposite side has 

 the normal slope of a V-shaped canon. The intervals between 

 the kernbuts occupied by the lakes are also too wide for the 

 normal profile of a V-shaped canon. This abnormal width and 

 sheerness of the walls is all the more striking when we compare 

 this portion of the canon with that in the bend of the river out- 

 side of the line of suspected rifting. Here the canon presents 

 the typical V-shaped profile. 



