422 University of California Publications in Geology [Vol. 9 



Tejon Group, Cantua District, Coalinga Quadrangle 



The great development of Eocene strata in the vicinity of Cantua 

 Creek in the northern portion of the Coalinga Quadrangle and their 

 complicated relationship to the underlying beds have interested several 

 investigators during the last ten years. The age of a portion of these 

 beds has been questioned by some investigators and a portion of these 

 Eocene strata has been assigned to the Martinez group. It is the 

 purpose of this discussion to show that the fauna of the lowermost 

 beds represent a lower zone of the Tejon group and that it is equivalent 

 to the Turbinolia zone of the Tejon group of Mount Diablo. A great 

 difficulty in the investigation of the Tejon group is found in the in- 

 complete description of its fauna. It has been the writer's experi- 

 ence in collecting in the Tejon group that new forms will be found 

 at practically all places where the preservation is slightly better 

 than usual. 



HISTORICAL 



F. M. Anderson 67 was the first writer to describe the beds in 

 the vicinity of Cantua Creek. He says : 



The preceding list of fossils contains representative Eocene species 

 such as indicate that the beds are to be correlated rather with the Tejon 

 than with the Martinez division of the Eocene, and this accords with the 

 fact that the latter horizon has been considered local in its occurrence, 

 or extending only northward from the latitude of Mount Diablo, and also 

 with the fact that the Tejon Beds are found at New Idria and other points 

 only a few miles north of the limits of our own observations. 



In a later paper 68 he suggested a Martinez age for the lowermost 

 beds. 



This area is also referred to by Arnold and Anderson. 69 

 J. A. Taff 70 described the stratigraphy of this region and sug- 

 gested that the lowermost Eocene beds might be of Martinez age. He 

 described an unconformity between these beds and the Domengine 

 sands. 



Professor E. T. Dumble 71 gave further notes upon the strati- 



67 Anderson, F. M., A Stratigraphic Study in the Mount Diablo Range of 

 California, Proc. Cal. Acad. Sci. Third Series, vol. 2, pp. 162-168. 



c8 A Further Stratigraphic Study in the Mount Diablo Range of Cali- 

 fornia, Proc. Cal. Acad. Sci. Fourth Series, vol. 3, pp. 13-14, 1908. 



es Arnold, Ralph and Anderson. Robert, Geology and Oil Resources of 

 the Coalinga District, California, Bull. 398, U. S. Geol. Surv., pp. 62-71, 191U. 



to Taff, J. A., Proc. Palaeontological Society, 1912. 



7i Dumble, E. T., Notes on Tertiary Deposits near Coalinga Oil Field 

 and their Stratigraphic Relations with the Upper Cretaceous, Jour. Geol., 

 vol. 20, pp. 28-37, 1912. 



