596 BRUCE L. CLARK 
The upper major Miocene division constitutes the San Pablo 
series, which is composed of three minor stratigraphic and faunal 
divisions, the Briones, Cierbo, and Santa Margarita groups. As 
will be brought out later, each one of these groups represents a 
distinct sequence of deposition and possesses a fairly distinctive 
fauna. 
Monterey series —Whether or not the Vaqueros and Temblor 
represent separate stratigraphic units has been the source of con- 
siderable disagreement in time past.t Nearly everyone, however, 
who has studied the fossils obtained from these beds has agreed 
that there are two fairly distinct, though closely related, faunas, 
one the fauna of the Turritella inezana zone, the other that of the 
Turritella ocoyana zone. 
Recent stratigraphic and paleontological work, the results of 
which are still unpublished,? appears to show that at certain locali- 
ties in California there were crustal movements of considerable 
magnitude between the deposition of the Vaqueros and the Temblor. 
The proper valuation of this hiatus is, in the writer’s mind, still an 
open question. ‘The faunas appear to be fairly closely related, and 
because of the obscure stratigraphic relations at various localities 
and the general similarity of the faunas the groups have usually 
been thrown together. The United States Geological Survey, in 
its more recent publications on Coast Range geology, applies the 
name ‘‘Monterey group” to these deposits, but the writer con- 
siders the Monterey a “‘series’’ because, at least in certain 
localities, it is composed of two epochs of deposition, the Vaqueros 
and the Temblor. 
Stratigraphic relations of the Monterey series to the Upper Oligo- 
cene.—There is no conclusive evidence that there were any great 
1G. D. Louderback, ‘‘Monterey Series of California,” Bull. Dept. Geol., Univ. 
Cal., Vol. VII (1913), No. 10, pp. 177-241. F. M. Anderson, “‘Stratigraphic Study 
of the Mount Diablo Range of California,” Proc. Cal. Acad. Sci., Third Series, Vol. II 
(1905), No. 2, pp. 161-248. F. M. Anderson, ‘‘ Further Study of the Mount Diablo 
Range of California,” Proc. Cal. Acad. Sci. Fourth Series, Vol. III. 
2 Mapping by Dr. Kew of the United States Geological Survey shows an important 
unconformity in southern California between the Temblor and the Vaqueros. Mr. 
Wayne Loel, formerly of Leland Stanford University, is working on a monograph of 
the Vaqueros. He believes that the faunas of the Temblor and the Vaqueros represent 
two distinct horizons. 
