STRATIGRAPHY OF SOUTHERN CALIFORNIA 131 
penetrates fossiliferous strata for its entire depth. The lowest 
beds are below the lower fossiliferous horizon of Pacific Beach, 
and are characterized by the large Arca schizotoma Dall (=A. sult- 
costa Gabb). 
Pleistocene.—The tilted brown sandstone of Pacific Beach is 
overlain unconformably by a layer of fossiliferous gravel and 
sand from two to fifteen feet thick (see Fig. 4), which probably 
covers much of the terrace of which the Pacific Beach sea cliff 
is the bounding escarpment. In this respect the gravel layer 
is similar to the gravel stratum which covers the San Pedro 
terrace. The gravel and sand series is characterized by a fauna 
which is entirely different from that of the underlying sandstones, 
but which is almost identical to the fauna of the upper beds of 
San Pedro. Upon this evidence the gravel and sand layers are 
placed in the upper San Pedro series. 
At the foot of Twenty-sixth street (see Fig. 5), and at Spanish 
Bight, beds of rather incoherent sands and fine gravels are 
exposed in the bluffs which form the shore line of the bay at 
these localities. These beds are richly fossiliferous, the fauna 
being similar to that of the upper San Pedro series at San Pedro, 
with which the Twenty-sixth street and Spanish Bight beds are 
correlated. 
REGION BETWEEN SAN DIEGO AND SAN PEDRO. 
The sea cliffs froma few miles north of Pacific Beach to near 
Newport are composed for the most part of soft dark colored 
shales and incoherent sandstones and gravels of late Pliocene 
and Pleistocene age. These deposits are mostly horizontal, but 
have been elevated in places to several hundred feet above sea 
level. 
W. L. Watts* reports a formation, probably contemporaneous 
with the San Diego formation, at San Juan Capistrano in which the 
remains of amastodon were found. Mr. Watts* has also reported 
tW.L. Warts, ‘‘Oil-and Gas-Yielding Formations of California,” Az/. Vo. 79, 
Cal, State Mining Bureau, pp. 59, 222, 1900. 
? Op. cit., pp. 61, 223. 
