242 



University of California Publications. 



[Geology 



THE STRATIFIED ROCKS. 



General Relations. — The stratified rocks consist prevailingly 

 of clay slates and phyllites with interbedded limestones, quart z- 

 ites, and large masses of tuffs and sheared volcanics, both acid 

 and more basic. Superficial oxidation has colored the series a 

 .strong red and causes them to stand out in pronounced contrast 

 to the gleaming white granites. 



The strike of the strata is fairly uniform throughout the 

 area, and does not vary greatly from N. 45° W. The dip is 

 nearly vertical, usually 85° to the southwest. The bedding is 

 in all cases found to be strictly conformable. At Mineral King 

 the series attains a maximum width of 12,000 feet. South of 

 Farewell Gap it narrows down to 5,600 feet. (See Plate 30.) 



The rocks have been sheared to greater or less extent and 

 exhibit various degrees of schistosity, from perfectly massive 

 quartzites to highly micaceous biotite schists. The interbedded 

 limestone beds show that the foliation is always coincident with 

 the original stratification planes. This is further borne out by 

 the thin sections, which frequently show the parallelism between 

 the sedimentary banding and the superimposed cleavage. 



The lithologic units are relatively small, and it was found 

 inadvisable to attempt to map them separately. The siliceous, 

 calcareous and argillaceous members are frequently stratified in 

 rapid alternation, and, as a further complication, even the larger 

 subdivisions are of strongly interdigitating habit and tend to 

 thin out in the direction of their strike. The volcanic rocks, 

 which constitute a large portion of the geologic series, are as 

 a general rule conformable in strike and dip with the sedimen- 

 tary rocks. They are strongly sheared, and have been invaded 

 by the granites and are, therefore, certainly pre-granitic. Asso- 

 ciated in conformable sequence with the quartz porphyries on 

 the Little Kern River are beds of tuffs, and the evidence is clear 

 that there the volcanics form an integral portion of the strati- 

 graphic column. At other points different evidence is obtain- 

 able. On Monarch Creek dykes of dark igneous rocks are intru- 

 sive into quartzites and are themselves cut by white aphanitic 



