Vol. 4] Lawson. — Features of the Middle Kern. 



403 



beyond the scarp. Owing to the impounding of the stream 

 detritus in the lake thus formed, the downward corrasion of the 

 trench beyond this notch would be slow. Meanwhile deltas 

 would be rapidly extended down the Kern and South Fork arms 

 of the lake. The embayment of the lake to the south of Isabella 

 would be filled partly by the silt of the river and partly by the 

 deltas of Erskine and Vaughn Creeks. The final result would 

 be an expansive flood plain sloping up in all directions from the 

 rock barrier in the notch of the fault-scarp through which the 

 river passed out to its normal channel. As soon as the flood plain 

 was completed by delta extension on to this point, coarse detritus 

 would begin to pass through the notch and the deepening of the 

 Kern trench beyond the scarp would proceed comparatively 

 rapidly. In consequence of this, the flood plain would be dis- 

 sected leaving terraces at the level of the flat floor of the infilled 

 trough to the south of Isabella. 



Pursuing now our observations up the Kern Eiver above 

 Kernville, we find the stream flowing in a profound but remark- 

 ably straight canon. The general trend of the canon is much 

 more nearly a straight line than is the course of the stream which 

 flows in it. On the west side of the canon the crest of the moun- 

 tains is in general about ten miles back from the river. Numer- 

 ous tributary streams enter from this side and all of them, as far 

 as Tobias Creek, twenty miles above Kernville, have built up 

 huge alluvial cones which indicate a marked lack of accordance 

 between the action of these affluents and the main stream, which 

 is itself running on bedrock and deepening its trench. The 

 material of these cones is in large part of a very coarse bouklery 

 character. It seems probable that the deformation of the country 

 on this side of the Kern which has been recognized in Brecken- 

 bridge Mountain and in the Greenhorn Mountains has in late 

 Quaternary time accentuated the grade of the upper reaches of 

 these affluents and caused them to deject great quantities of allu- 

 vium into the main canon. It is even quite probable as an infer- 

 ence from the existence of these cones that, if the country a few 

 miles back from the stream were examined, a fault scarp would 

 be discovered, the dissection and degradation of which has given 

 rise to the alluvium. 



