NOTES ON TERTIARY DEPOSITS NEAR COALINGA OIL 
FIELD AND THEIR STRATIGRAPHIC RELATIONS 
WITH THE UPPER CRETACEOUS 
E. T. DUMBLE 
Consulting Geologist Southern Pacific Company 
The work of the California division of the geological depart- 
ment of the Southern Pacific Company during the spring of tg10 
was devoted in part to the differentiation and careful definition of 
the oil-bearing formations of the Coalinga district and the area 
lying north of it and the mapping of the surface exposures of each 
as accurately as conditions would permit. Two field parties were 
engaged in this work, one of them comprising Mr. J. A. Taff, 
assisted by Mr. B. L. Cunningham, and the other Mr. F. M. 
Anderson, assisted by Messrs. G. C. Gester and E. A. Hardy. The 
work begun here is being extended to cover the west side of the San 
Joaquin Valley. As soon as the collections and field data have been 
properly studied, it is hoped that papers may be published by these 
geologists giving the geological details fully, but, since such publica- 
tions may be delayed, I have arranged the following statement of 
some of the results of the early work, based on their preliminary 
reports and maps. 
PREVIOUS WORK 
The first two publications based directly upon the work of this 
department in this area were those by Mr. Frank M. Anderson, 
entitled ‘‘A Stratigraphic Study in the Mount Diablo Range of 
California,’ in 1905, and ‘‘A Further Stratigraphic Study in the 
Mount Diablo Range of California,’ in 1908. Prior to our work, 
we have only the reports of Mr. W. L. Watts in Bulletins Nos. 3 
and rg of the California State Mining Bureau and the paper of 
Mr. George H. Eldridge in Bulletin No. 213 of the United States 
t Proc. California Acad. Sct., 3d series, Geology, II (1905), 156-248. 
2 Tbid., 4th series, Geology, III (1908), 1-40. 
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