224 University of California Publications in Geology [Vol. 10 



the approximate equivalent of the San Pablo." The Etchegoin as 

 recognized by Arnold and Anderson was placed in the upper Miocene. 

 The Purisima was believed to be higher than the Etchegoin and of 

 Pliocene age. 



In a short paper by W. A. English 37 on the Fernando near New- 

 hall, Los Angeles County, California, the conclusion was arrived at that 

 the lower Fernando probably does not differ greatly in age from the 

 Etchegoin of Arnold and Anderson. 



In a recent paper by R. W. Pack and W. A. English 38 on the region 

 west of the Coalinga district little attempt was made at a faunal study 

 of the Etchegoin. The Jacalitos and Etchegoin were grouped as upper 

 Miocene. According to these writers, "the Jacalitos and Etchegoin 

 formations are believed to be in the main younger than the true Santa 

 Margarita, although the fauna contained in the lower part of what is 

 mapped as upper Miocene in Waltham Canon shows a close similarity 

 to that of the true Santa Margarita." 



The Jacalitos and Etchegoin are grouped by Robert Anderson and 

 R. W. Pack 39 as upper Miocene, or possibly in part lower Pliocene, 

 and are thought to be of the same age as the San Pablo. 



By finding remains of land mammals with the marine deposits in 

 the Etchegoin it becomes possible to correlate this group definitely 

 also with distant terrestrial deposits containing only remains of land 

 vertebrates. The mammalian remains have been studied by Professor 

 J. C. Merriam, 40 who places both the Etchegoin and Jacalitos of 

 Arnold and Anderson in the Pliocene. The Santa Margarita-San 

 Pablo is placed in the upper Miocene. 



The study of the San Pablo of middle California by Dr. B. L. 

 Clark apparently shows that this group is of upper Miocene age. The 

 Santa Margarita is considered by him equivalent to the upper part of 

 the San Pablo, while the Etchegoin is recognized as Pliocene. Dr. 

 Clark states that it is his opinion that the Jacalitos is probably younger 

 than the San Pablo. 



In a recent publication on the Pliocene of California by Bruce 



3 7 English, W. A., The Fernando Group near Newhall, California, Univ. Calif. 

 Publ. Bull. Dept. Geol., vol. 8, no. 8, 1914. 



38 Pack, E. W., and English, W. A., Geology and oil prospects in Waltham, 

 Priest, Bitterwater, and Peachtree valleys, California, IT. S. Geol. Surv. Bull. 

 581D, 1914. 



39 Anderson, Eobert, and Pack, B. W., Geology and oil resources of the west 

 border of the San Joaquin Valley north of Coalinga, California, U. S. Geol. Surv. 

 Bull. 603, 1915. 



40 Merriam, J. C, Tertiary vertebrate faunas of the North Coalinga Begion 

 of California, Trans. Am. Philos. Soc, vol. 22, pt. 3, 1915. 



