32 CALIFORNIA ACADEMY OF SCIENCES [Proc. 47H SER. 
neighboring and intermontane valleys of the state. It is not 
improbable that the equivalents of the Tulare will be found 
to include the thick delta deposits of the San Benito and Salinas 
valleys described by Dr. Lawson’ and later by Dr. H. W. 
Fairbanks.’ If this correlation is correct, then according to 
Dr. Lawson they should also include the marine beds of the 
Merced series, which are generally regarded as of late Pliocene 
age. The Tulare formation should also have its equivalents 
among fresh-water deposits of the Great Basin region, but a 
discussion of this topic can not be undertaken here. Undoubt- 
edly there is a close relation between these deposits and the 
Pleistocene deposits and terraces described below. Just what 
that relation may be can not now be stated with certainty, 
but probably the time interval was short between the close 
of the Tulare epoch and the opening of the Pleistocene. 
THE PLEISTOCENE RECORD 
The evidences of the Pleistocene period in the Mount Diablo 
range are confined to the foothills and the marginal plains of 
the Great valley. As far as known, there are no stratified 
beds distinct from those of the Tulare formation appearing 
along the range that could be classed as Pleistocene, though 
there are abundant evidences that the period, at least in part, 
was one of submergence if not of inundation. 
The Terraces—Along the flanks of the range upon both 
sides, and about the southern end of the Kern valley, there 
are many elevated terraces and other remnants of ancient 
plains that must have circumvented the Great valley. These 
elevated terraces and mesas are not all of uniform height, and 
this fact may be taken as an evidence of a series, rather than 
of a single plain of base-leveling, though in some places the 
variations of level are only those of a somewhat varied topog- 
raphy rather than those of an absolute plain. These terraces 
may be seen to advantage about the lower Kern river, the 
1 Bull. Dept. Geol. Univ. Calif. v. 1, p. 153. 
2 Jour. Geol. v. 6, pp. 551-576; U.‘S. Geol. Surv. San Luis folio, pp. 11-12. 
