SANTA CLARA VALLEY: PICO FIELDS. 
91 
and on the map (PL I) the syncline is in the main given as unbroken. 
The similarity between this fold and the Tapo anticline is worthy of. 
remark. In each case there is a principal anticlinal fold, with a par¬ 
allel syncline on the south, and faults and a highly crushed zone in 
one instance and perhaps also in the other still farther south. The 
position of the Pico anticline is en echelon with that of the Tapo to 
the west and also with that of the Elsmere to the east, all being: 
somewhat diagonal in trend to the general direction assumed by the 
ranges. 
The strata involved in the folds described above and underlying 
the adjacent regions include a heavy deposit, presumably of lake 
beds, in the low hills about the junction of Santa Clara River and 
its tributary, Newhall Creek; conglomerate, sandstone, and clay of 
the Fernando, of a horizon possibly somewhat younger than that of 
the Fernando beds that lie immediately east of the mouth of Piru 
Creek; and a succession of brown and chocolate-colored shale, com¬ 
paratively thin interbedded sandstone, and local conglomerate, 
which will doubtless prove to be of lower Miocene (Vaqueros) age, 
of the same horizon as the beds of similar nature in the region of 
Torrey and Tapo canyons and in the northern front of Oak Ridge 
farther west. The assumption that the beds last mentioned are 
lower Miocene is, in the absence of fossils, based on their lithologic 
resemblance to those of other localities in which determinative forms 
occur, on the presence of organic siliceous shale here and there in the 
beds of chocolate-brown color and of more earthy character, and on 
the occurrence of concretionary bodies, round to elliptical, in the 
sandstone of the formation. The shale and sandstone regarded as 
Vaqueros are confined to the heart of the anticline and to the regions 
adjacent which are affected by the subordinate folds in connection 
therewith. They occupy the entire front of the range to their line 
of union with the Fernando beds near the base. 
The Fernando formation displays marked regularity of strike and 
dip, and from any of the high points within the range may be seen 
arching about the foothills from the vicinity of Newhall across Pico 
Canyon to the mouth of Salt Creek, bending in its trend from N. 
50° W. to N. 75° W. A conspicuous feature of this formation is a 
great mass of bluish-gray clay that occurs a short distance above its 
base. It is particularly strong of outcrop in Road Gulch, perhaps 
on account of the gentle dip and wide erosion of this portion of the 
formation. The conglomerate which overlies this clay is heavily 
developed in beds from 50 to 300 feet thick. 
The line between the Fernando formation and the beds regarded 
as Vaqueros is placed at the horizon of the uppermost brown or 
chocolate-colored shale. Conglomerate extends below this horizon, 
but not of the importance attained by those above. The manner 
