610 BRUCE L. CLARK 
in Oregon, we have the “‘Empire” formation;? in northern Cali- 
fornia, the ‘Wildcat’’;? in the region of San Francisco Bay, the 
““Merced”’;3 and a little to the south of this, in Santa Cruz County, 
is the “‘Purissima.’’4 Still farther to the south are the “‘Jacalitos” 
and “‘Etchegoin”’ formations in the Coalinga region;> the ‘‘Pico”’ 
and “Saugus” formations of the Fernando group® in the Ventura 
region and the “San Pedro’ and “‘San Diego”’ Pliocene deposits 
on the southern California coast. The “Purissima,”’ ‘ Jacalitos,” 
“Etchegoin,’’ and ‘“‘lower Fernando” have in the past been referred 
to the Upper Miocene and correlated with the San Pablo of middle 
California. 
During the last few years our ideas of the sequence of these 
various formations have been very radically revised as the result 
of more detailed studies of vertebrate and invertebrate faunas. 
The writer’s study of the San Pablo series convinced him that the 
faunas of that series belong to an older horizon than those of the 
Jacalitos-Etchegoin, Purissima, and Pico, and that the percentage 
of recent species in the latter beds indicate Pliocene age. Later 
work by Dr. Nomland on the Jacalitos and Etchegoin of the Coa- 
linga region corroborated these conclusions. 
=W. H. Dall, ““The Miocene of Astoria and Coos Bay, Oregon,” U.S. Geol. 
Surv., Prof. Paper 59 (1909), pp. 1-261. 
2A. C. Lawson, “‘The Geomorphogeny of the Coast of Northern California,” 
Bull. Dept. Geol., Univ. Cal., Vol. I, No. 8 (1894), pp. 24-272. Bruce Martin, ‘“ Pliocene 
of Middle and Northern California,’ Bull. Dept. Geol., Univ. Cal., Vol. IX (1916), 
No. 15, pp. 215-59. 
3 A. C. Lawson, U.S. Geol. Surv., Folio 193, San Francisco Folio; ‘‘Post-Pliocene 
Diastrophism of the Coast of Southern California,” Bull. Dept. Geol., Univ. Cal., 
Vol. I, No. 4 (1893), pp. 115-60. 
4J. C. Branner, F. G. Newsom, and R. Arnold, U.S. Geol. Surv., Folio 163, Santa 
Cruz Folio. 
5 J. O. Nomland, “‘ Fauna of the Lower Pliocene at Jacalitos Creek and Waltham 
Canyon, Fresno County, California,” Bull. Dept. Geol., Univ. Cal., Vol. IX (1916) 
No. 14, pp. 199-214; ‘‘Etchegoin Pliocene of Middle California,” Bull. Dept. Geol., 
Univ. Cal., Vol. X (1917), No. 14, pp. 191-254. R. Arnold, “Palaeontology of the 
Coalinga District, California,” U.S. Geol. Surv., Bull. 396 (1909), pp. 5-169. 
6W. A. English, “‘Fernando Group near Newhall California,” Bull. Dept. Geol., 
Univ. Cal., Vol, VIII (1914), No. 8, pp. 203-8. 
7R. Arnold, “Palaeontology and Stratigraphy of the Marine Pliocene and Pleisto- 
cene of San Pedro, California,” Cal. Acad. Sci., Memoir IIT (1903). 
