16 CALIFORNIA ACADEMY OF SCIENCES [Proc. 47H SER. 
in some places an angular difference in strike and dip is plainly 
to be seen. Furthermore, as the formations are followed 
southward, the series with which these shales are identified 
finally disappears beneath the later series. 
The upper shales do not maintain the thickness stated above 
as they are followed southward. In the vicinity of the Domen- 
gine ranch, they are reduced to about 1000 feet, while at “Oil 
City” the thickness is not above 600 feet, and that of the 
entire Eocene series is only about 2500 feet. Farther south 
and west they entirely disappear in the western part of the 
Coalinga district. 
The fauna of these shales consists of many forms of Fo- 
raminifera and marine diatoms, but with a scanty number of 
mollusks. 
On the Cantua the upper white shales contain Pecten peck- 
hami and many Foraminifera and diatoms. Near “Oil City” 
Pecten peckhami and other forms have been found by the 
writer and by W. L. Watts. Intermediate between these two 
localities, on Sec. 19, T. 18 S., R. 15 E., these white shales 
have furnished: 
Pecten peckhami GaBB. Tellina congesta (?) CoNRAD 
Leda oregona (?) SHUM. Callista sp. 
It was these upper brown and white shales which, on the 
basis of both their lithology and their molluscan fauna, were 
regarded as Miocene, and therefore as “Monterey shales”, in 
the former paper. Had the succeeding Lower Miocene series 
been as fossiliferous, however, as new localities have since 
shown it to be, or had it been followed into the localities where 
the great unconformity is more evident, it would have been 
less easy to confuse these earlier shales with their counterparts 
in the Miocene. 
As to the definite assignment of these shales to either the 
Eocene or the Oligocene in the time scale of California geol- 
ogy, that must be reserved for further study and for some 
future time. Stratigraphically and structurally they are cer- 
tainly connected closely with the Tejon series, while faunally 
they are allied more closely to the Miocene. 
