74 
OIL DISTRICTS OF SOUTHERN CALIFORNIA. 
The logs are given in the vernacular of the driller. It is probable 
however, that adobe and clay are one and the same, except that the 
former is perhaps somewhat more tenacious than the latter. Shale is 
distinguished from clay by being less sticky and more inclined to 
come up in minute slivers. The sands are distinguished by colors, 
but this feature is not significant. The water sands are those in 
which water has been encountered in drilling, and it is to be observed 
that they are in alternation with the oil sands, the two being in places 
adjacent; in places separated by a clay parting. Mr. Sperry, man¬ 
ager of the Modelo Oil Company, believes that at least a thin stratum 
of shale between such sands is the rule. It is difficult to explain the 
alternation of water and oil sands if consideration is given to the sup¬ 
posed transmigration of the oil from its seat of origin in the shales into 
the sandstones, which serve as reservoirs. It has been suggested that 
this alternating occurrence may be accounted for by considering each 
pair of layers—the oil above and the water below—as occupying an 
isolated channel or reservoir, the segregation having taken place after 
their entrance into the containing strata on account of the difference 
in specific gravity of the two fluids. Nearly all the wells periodically 
pump more or less water with the oil, at times in the proportion of 3 
barrels of water to 1 barrel of oil, at other times in equal amount. 
The continuity of sands bearing water and oil need not be regarded as 
indicating that the two are mixed in their natural occurrence, but 
only that both flow into the well from the same bed, the oil perhaps 
resting upon the water in the reservoir. 
The bowlders referred to in the log of well No. 24, between the 
depths of 755 and 875 feet, are unquestionably the concretions that 
characterize the lower Modelo sandstone. 
The yield of the Modelo wells is between 5 and 15 barrels per day, 
and Mr. Sperry states that since 1897 there has been no perceptible 
decrease in the amount. Of course for the first few days the yield 
was considerably in excess of these figures. The oil is black and 
its gravity ranges between 25° and 32° B., with perhaps 28° as an 
average. The wide variation in gravity of the oil from these wells is 
a feature that is difficult to explain. 
Strong seepages are found along the canyon in the debris that fills 
the bottom. The sandstone in the arch of the anticline also is dark, 
with bitumen contents, especially on the northern side of the axis. 
WELLS OF THE PIRU OIL AND LAND COMPANY. 
The productive wells of the Piru Oil and Land Company are located 
in the valley of Piru Creek, about 2 miles northeast of Piru. At pres¬ 
ent two wells yield oil and one water. They penetrate conglomerate 
and sandstone, with some clay, which are believed from their fossils 
to be the Fernando formation. The general dip of the strata is from 
