Vol. 4] Lawsoii. — Tehachapi Valley System. 435 



not more than a dozen ranchers actually engaged in the cultiva- 

 tion of the soil. Portions of it are, however, utilized as cattle 

 ranges. 



Another indication of the volume of alluvium in the valley 

 is afforded by the dissection of the alluvial cone of Antelope 

 Creek at its apex. Here Antelope Creek has greatly deepened 

 its rocky gorge within the mountains since the apex of the alluvial 

 cone was established, and this deepening of the gorge has necessi- 

 tated the dissection of the cone. The extension of the gorge 

 through the apex of the fan reveals a section of alluvium 250 

 feet thick above the stream. In the vicinity of the apex of the 

 China Hill alluvial cone a much greater thickness may be 

 inferred. Here the coarse gravels of the upper part of the cone 

 have been hydraulicked for placer gold. 



Isolated Hills. — An interesting feature of the valley floor is 

 the occurrence of certain isolated rocky hills which project as 

 island-like masses through" the alluvium. There are two such 

 hills of prominence, both on the north side of the valley and 

 both composed of the granitic rocks of the surrounding moun- 

 tains. One of these lies to the northeast of Tehachapi and less 

 than a mile distant from the town. It rises to an altitude of 

 perhaps 100 feet above the surrounding plain as a rugged more 

 or less conical mass of bare rock. The other is at the east end 

 of the valley and lies at its confluence with the wide-gaping tribu- 

 tary valley of Cache Creek. It is surrounded by the alluvial fan 

 of that creek, the stream, which is now to the east of the hill, 

 having formerly flowed to the west. The hill is about half a 

 mile in length from north to south and about half as wide at its 

 base and it is probably not less than 200 feet high, its bare rocky 

 precipitous slopes being in striking contrast to the surrounding 

 alluvial plain. The isolation of these hills from the neighboring 

 mountain slopes affords additional suggestion as to the great 

 depth of the alluvial infilling of the valley, and indicates some- 

 thing of the irregularity of the rock surface upon which the 

 alluvium, in parts of the valley at least, rests. The best actual 

 exposure of alluvium of the valley floor which came under the 

 writer's observation was that afforded by a trench at the extreme 

 eastern end of the valley at from one-half to three-quarters of 



