314 CONTRIBUTIONS TO ECONOMIC GEOLOGY, 1902. [bull. 213. ' L 
li 
bara. The wells are located on the bluffs, the shore, and upon wharves * 
extending into the sea for nearly a quarter of a mile. The physical 
aspect of the country is that of an undulating but highly cultivated | 
terrace, 3 or 4 miles wide, lying between the sea and the lofty and" 
abrupt range of the Santa Ynez Mountains, which parallels the whole f 
coast of Santa Barbara County. 
The formations of the region are the equivalents of the great red 
sandstone series of the Sespe Canyon, 50 miles to the east; a series of 
rusty sandstones and shales, with their interbedded, concretionary 
limestones overlying the foregoing; siliceous and argillaceous shales 
of Monterey type; a succession of conglomerates, sandstones, and 
clays believed to be the equivalent of the San Pablo, and from 100 to 
200 feet of Quaternary sands and gravels. An unconformity is evi- 
dent between the Quaternary and the San Pablo and between this 
latter formation and the Monterey. 
The structure of the region has not been entirely worked out, but 
there exists an anticline with axis exposed in the red beds along a line 
midway between ocean and mountain base. North of the axis there 
is, for a distance, apparently the same succession of strata as in the 
Sespe region ; that is, the red beds are overlain by a series of rusty 
sandstones, shales, and limestones. Beyond these, however, along 
the higher mountain slopes, the present examination did not extendi. 
South of the anticlinal axis the red beds, with a dip southward of 
from 45° to 80°, are succeeded by shales of Monterey type, and these, 
in the immediate vicinity of the shore, by the probable equivalent of 
the San Pablo. The Quaternary is exposed in the ocean bluffs, and 
here and there overlaps the older formations far toward the moun- 
tains. From the difference in the succession of the formations south 
and north of the anticlinal axis it is possible that an important fault- 
extends along the bench lands of this portion of the ocean's front, the 
throw of which can not be less than 4,000 or 5,000 feet. An alterna- 
tive of this fault may be an unconformity between the siliceous shales 
of the Monterey and the red beds of the Sespe formation. 
The Summerland oil field is developed in strata having a southerly 
to southwesterly dip of from 30° to 90°. It lies at a distance of approx- 
imately 1 mile from the axis of the anticline. The source of the 
oil is in one or more sands of the formation believed to be the equiv- 
alent of the San Pablo, at a distance not far from its line of union 
with the underlying Monterey. The well records in the main point 
to a body of oil sand from 80 to 120 feet below the derrick floor, and 
to another 40 or 50 feet below this, but many of the wells extend to 
depths of 400 or 500 feet. The oil throughout the field is mixed with 
a considerable amount of water, which is probably due to careless 
methods in drilling, although it may be from the shallow depths of 
the wells that sea water has penetrated to the productive beds. The 
gravity of the oil in the upper and lower sands is said to be, approx- 
