22 
OIL DISTRICTS OF SOUTHERN CALIFORNIA. 
BURNING OF THE SHALE. 
The siliceous shale and ‘ 1 chalk rock ’ ’ forming the crest of the moun¬ 
tains south of the Santa Clara have at many points been burned to a 
bright-red color. The fuel which supported such fires was perhaps 
the originally contained petroleum. 
Opposed to this view, however, is the very considerable depth to 
which the shale has been altered to a brilliant-red lava-like rock; hence 
it may be inferred that spontaneous combustion alone has brought 
about the modification. 
FERNANDO FORMATION. 
GENERAL CHARACTER AND AGE. 
The rocks that have received the name Fernando® consist of an 
enormous succession of conglomerates, sandstones, and arenaceous 
clays, largely of Pliocene age, developed over considerable portions of 
southern California. Fossils collected at many localities and at many 
horizons throughout the formation indicate that it extends from the 
upper Miocene '(San Pablo formation of the general geologic column 
of the State) well up in the Pleistocene (San Pedro formation). It 
is possible to subdivide the formation locally on both lithologic and 
paleontologic grounds, but taken over a considerable extent of terri¬ 
tory these divisions merge into one another both stratigraphically and 
geographically by insensible gradations. An unconformity usually 
marks both the base and the top of the formation, although in several 
localities in the Santa Clara region that at the base is difficult if not 
impossible to detect. 
Along the sides of the Santa Susana Mountains and Oak Ridge and 
in the region east of Newhall the coarser beds of this formation are 
usually white, gray, or yellow, the clays bluish gray. The material 
of the conglomerate is principally granitic, but pebbles of the inter¬ 
mediate formations are occasionally found. In the limited region 
under survey no established succession of the different sediments was 
observed, although a broader field would doubtless reveal it. The 
unconformities are always to be reckoned with, and to them may be 
due in large measure the variations in the rocks that are in contact. 
Incidentally it may be observed that perhaps to them also may be 
due the fact that whereas south of the general fold out of which the 
several ranges are formed the Fernando is usually in contact with 
siliceous shale, north of the anticline, on the slopes of the Santa Susana 
Mountains, it is found resting directly upon beds that are of the 
Vaqueros facies. 
a A term applied in unpublished maps by Homer Hamlin a number of years ago to the beds above the 
siliceous shale skirting the sides of the San Fernando Valley, Los Angeles County—the general equiva¬ 
lents of all the post-Modelo, pre-Saugus beds in the Santa Clara province. 
