THE SANTA CLARA VALLEY OIL DISTRICT. 
SOUTHERN CALIFORNIA. 
By George Homans Eldridge. 
INTRODUCTION. 
This paper presents a brief description of the oil fields of the region 
adjacent to the Santa Clara Valley, in Ventura and Los Angeles 
counties, Cal. Owing to the somewhat limited time available for the 
field work it has been impossible to go into as much detail concern¬ 
ing certain of the fields as might be desirable. However, it is hoped 
that the data here brought together will be of assistance in the 
future development of the district. Figures of the characteristic or 
common fossils of the different formations of the district are given 
in Pis. XXV to XLI. The physical and chemical properties of the 
oil are treated on pages 203-218. 
ACKNOWLEDGMENTS. 
The writer wishes to extend his sincere thanks and acknowledg¬ 
ments to the officers and operators of the different oil companies in 
the district for their hearty cooperation and support. Without the 
data furnished by them the preparation of such a report as this 
would have been impossible. 
TOPOGRAPHY. 
The Santa Clara Valley of southern California is a structural 
depression modified by erosion. The heads of the valley lie in the 
San Gabriel Range and in the mountains to the north, which con¬ 
nect this range with other portions of the Coast Range and with 
the Sierras. After a westerly course of 75 miles the stream which 
drains the valley enters the Pacific a little south of the town of 
Ventura. The valley proper is given over to agriculture, but in 
the mountains on either side are many important oil fields. 
The mountains north of the valley form the watershed between 
it and the Central Valley of California and also present a barrier to 
the Mohave Desert, which lies in the angle between the Sierras 
and the more southerly ranges of the State. These mountains are 
l 
