104 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4TH SER. 
ous in places, even to near the top; while on the Kern River 
side the upper beds are destitute of fossils, except for a few 
which serve little for correlation. 
The problems of correlation appear to be such as can be 
solved satisfactorily only by reference to the physical geog- 
raphy and other conditions attendant upon Neocene sedimenta- 
tion, and in the light of facts gathered from districts somewhat 
outside the one under discussion. Doubtless marine currents 
during Neocene times played no small part in the distribution 
of the materials, and hence with the stratigraphy and thickness 
of the beds, and possibly also with their faunas. But it is 
only by recognizing the entire extent and position of the 
particular basin of deposition and its physical history that we 
gain the view requisite for the problems of correlation. 
THE TEMBLOR BASIN 
As shown on the maps contained in this paper the basin of 
deposition did not conform either in extent or position to the 
Great Valley of California, but, as has been pointed out in 
former papers,’ it included not only a portion of the Great 
Valley, but also the intermontane valleys to the west. This 
basin was subsequently somewhat roughly described and out- 
lined by Dr. Arnold in a paper giving broad generalizations 
of the environment of the Pacific Coast Tertiary faunas.” 
From evidences that cannot be fully presented here it is 
believed that the Neocene basin of the California Interior was 
bounded on the east by the Sierra Nevada, on the south and 
west by the Tehachipi and Santa Lucia ranges, and on the 
north by a low plain, in part skirting the Sierra, but in the 
main occupying the northern portion of the Great Valley. 
The exact position of the shore-line cannot be stated, but it 
probably crossed the Great Valley obliquely in a northwesterly 
direction, receding more and more from the position of the 
Sierran foot-hills as it is followed northward. It is unlikely 
that this shore-line held its place continuously throughout the 
Neocene, but more probably its locus was shifted somewhat 
1Proc. Calif. Acad. Wet eae 3d ser., Geol., v. 2, pp. 157-158; Proc. Calif. Acad. 
Sci., 1908, 4th ser., By -7. 
gout Geol. 1909, a in ‘pp. 320 et seq. ; 
