THE MARINE TERTIARY OF THE WEST COAST 587 
hiatuses.t Thus, on the West Coast, the Eocene period may be 
definitely stated to be made up of at least three epochs of deposition 
and should be recognized as a true period rather than as an epoch. 
Correlation of Eocene deposits.—The evidence for the correlation 
of the West Coast marine Eocene with that of the Gulf and East 
Coast provinces and through them with Europe is based upon the 
identity of species or the presence of closely related forms common 
to the two regions. The evidence appears to be much better for 
the correlation of the Meganos and the Tejon (Middle and Upper 
Eocene) than for the Lower or Martinez group. There can be 
little doubt but that during those epochs of time there was a direct 
connection between the Gulf of Mexico and the Pacific Ocean. 
Climate-——The climate during the Eocene of the West Coast 
was subtropical or possibly warm temperate rather than tropical. 
The arkosic character of the Meganos deposits, a character very 
general on the West Coast, strongly suggests that we are dealing 
with deposits which were derived from an arid coast, while Tejon 
sandstones, at most localities in California, are composed almost 
entirely of pure quartz grains, indicating humid climatic conditions 
at that time.” 
(Fig. 1.) Paleogeography.—As indicated by the paleogeographic 
maps, the deposits of the Martinez group (Lower Eocene, Fig. 2) 
were laid down in much more limited basins than those of the 
Meganos and Tejon groups. Apparently there were at least four 
separate basins in California, the connections between which were 
indirect. It seems very probable that when the faunas obtained 
from these four areas have been more fully described, we shall find 
that the geographical factor has caused considerable difference 
between them. 
=R. E. Dickerson, ‘Fauna of the Martinez Eocene of California,” Bull. Dept. 
Geol., Univ. Cal., Vol. VIII (1914), No. 6, pp. 61-180. B. L. Clark, ““The Meganos 
Group, a: Newly Recognized Division in the Eocene of California,” Bull. Geol. Soc. Am., 
Vol. XXVIII (1018), pp. 218-96; “Stratigraphy and Faunal Relationships of the 
Meganos Group, Middle Eocene of California,” Jour. Geol., Vol. XXIX (1921), No. 2, 
pp. 125-65. 
2R. E. Dickerson, “Climatic Zones of Martinez Eocene Time,” Proc. Cal. Acad. 
Sci., Fourth Series, Vol. VII (1917), No. 7, pp. 193-96. 
