1915] 



Clark: Fauna of the San Pablo Group 



431 



One of the first papers published by the United States Geological 

 Survey dealing with the distribution of the oil of California was by 

 George Homans Eldriclge, 31 on the "Santa Clara Valley Oil District, 

 Southern California." This appeared in 1907 and marks the beginning 

 of a series of publications on the different oil fields of California, 

 which have greatly stimulated the study of the Tertiary palaeontology 

 of California. This paper was edited by Dr. Ralph Arnold after the 

 death of Mr. Eldridge in 1905. 



The section described is in the vicinity of Santa Clara Valley, 

 Ventura and Los Angeles counties. A very thick series of Upper 

 Neocene, designated the Fernando, is described as overlying the Lower 

 Neocene (the Vaqueros and the Modelo). In speaking of this series 

 Eldridge says : 



The rocks that have received the name Fernando consist of an enormous 

 succession of conglomerates, sandstones and arenaceous clays, largely of Plio- 

 cene age, developed over considerable portions of Southern California. Fossils 

 collected at many localities and horizons throughout the formation indicate 

 that it extends from the Upper Miocene (San Pablo formation of the general 

 geologic column of the state) well up into the Pleistocene (San Pedro forma- 

 tion). It is possible to subdivide the formation locally on both lithologic and 

 palaeontologic grounds, but taken over a considerable extent of territory these 

 divisions merge into one another both stratigraphically and geographically by 

 insensible gradations. 



A fairly large fauna is listed from the Fernando on pages 24-28 of 

 this bulletin. The fauna is divided into three separate lists, repre- 

 senting the lower, middle and upper horizons. The author states that 

 — the oldest fauna was found in the area north and northeast of 

 Camulos, and is according to J. C. Merriam, the equivalent of the 

 fauna of at least a part of the San Pablo formation. The middle 

 fauna was found well developed in the region of Elsmere Canon and 

 Fernando Pass and probably represents the typical fossiliferous por- 

 tion of the Purisima and the lower part of the San Diego formation. 

 The upper part of the Fernando extends Avell up into the Pleistocene, 

 as is attested by the fossils found at Barlows' ranch and on the south 

 slopes of Mount San Cayetano. The fauna listed from the lower 

 Fernando is now known to belong to a higher horizon than the San 

 Pablo, being as young as or younger than the Etchegoin or Purisima. 

 Further reference will be made to this in the discussion of another 

 paper. The list given on page 26 credited to J. G. Cooper obviously 

 contains the names of a number of incorrectly identified species. For 



3i U. S. G. S. Bull. No. 309, pp. 71-101, 1907. 



