220 University of California Publications in Geology [Vol. 9 



argillaceous sand with calcareous nodules. This series was named 

 the Cape Blanco Beds and correlated with the Empire of Coos Bay 

 on palaeontological evidence. This formation was reported to ex- 

 tend from Cape Blanco to the mouth of Elk River, where it was 

 seen to dip beneath the beach sand. The sediments also occur 

 along the cliffs north of Black Lock Point. Overlying unconform- 

 ably the Cape Blanco Beds were a series of sands and gravels, the 

 lower portion of which was very fossiliferous. This series was 

 named the Elk River Beds. A collection of fossils made by Diller 

 was submitted to Dr. Dall who made the following report: "They 

 are probably Pleistocene, all of the species seeming recent, but they 

 may be of the Merced horizon ; they are not older than the newer 

 Pliocene." Diller thought that the interval between the Cape 

 Blanco Beds and the overlying Elk River Beds might represent a 

 long period and that the Merced and the "Wildcat formations were 

 deposited during that time. 



In 1903 Ralph Arnold published a memoir on the "Palaeontology 

 and Stratigraphy of the Marine Pliocene and Pleistocene of San 

 Pedro, California." 11 In this publication the author correlates a 

 number of the Pliocene and Quarternary formations along the coast 

 with those at San Pedro. The greater part of the Merced Series 

 is considered to be above the San Pedro and the San Diego Pliocene. 



The Proceedings of the American Philosophical Society contains 

 an article by Haehl and Arnold which deals with the diabases of 

 the Santa Cruz Mountains. 12 In this paper a new formation is de- 

 scribed to which the name Purisima is given. This formation con- 

 sists of conglomerates, fine-grained sandstones, and shales which 

 were typically developed in the vicinity of Purisima Creek, San 

 Mateo County, California. The beds were found to be unconform- 

 able upon the A^aqueros sandstone and the Monterey shale, and at 

 the top graded into beds having a fauna somewhat similar to that 

 of the Merced Formation. The individuality of the fauna, strati- 

 graphy, and the lithology of this formation appeared to warrant 

 the application of a new and distinct name. The formation was 

 thought to represent the middle and the lower portion of the Pliocene. 



In 1905 Vance Osmont described a geological section across the 

 coast ranges north of San Francisco Bay. 13 In this section he re- 



11 Calif. Acad. Sci., Memoirs, vol. 3, 1903. 



12 Proc. Amer. Phil. Soc, vol. 43, pp. 22-24, 1904. 



is Univ. Calif. Publ. Bull. Dept. Geol., vol. 4, pp. 39-87, 1905. 



