STRATIGRAPHY OF SOUTHERN CALIFORNIA 123 
the Deadman Island Pliocene was deposited under conditions 
somewhat analogous to those now prevailing in the ocean off 
San Pedro at depths of from twenty to fifty fathoms. There is 
a marked difference, however, between the Pliocene fauna and 
that now living off San Pedro, the former being characterized 
by the abundance of the individuals and species which are now 
found living only far north of San Pedro. To state it more pre- 
cisely, out of the Pliocene fauna of eighty-seven species, 18.5 
per cent. are found living now only north of San Pedro, and 
nearly all of the remaining species yet hving show a decided 
predilection for boreal or subboreal conditions. The occurrence 
in large numbers in the Deadman Island Pliocene of Pecten cau- 
rinus, Panomya ampla, Thyasira bisecta, Pecten hericeus, Lucina 
acutilineata, Natica clausa, several species of Zvophon and northern 
Pleurotomide, and other boreal and subboreal forms leads to the 
conclusion that these Pliocene strata were deposited in water 
much colder than that which is now found in the vicinity of 
San Pedro. Boreal or subboreal conditions so near the shore 
imply boreal or subboreal climatic conditions on the land, at 
least near the ocean. This being true, it is safe to assume that, 
during the latter part of the Pliocene epoch, the climate was much 
colder on the coast of southern California than it is at present. 
The lowest, or brown sandstone, series of Deadman Island is 
called Pliocene for several reasons. First, it overlies uncon- 
formably the. Miocene shales, from which it differs widely both 
lithologically and faunally. Second, it contains a fauna over 12 
per cent. of which are extinct species, and many of the remain- 
ing species are those now found living only in places remote 
from San Pedro. This evidence precludes any possibility of its 
being Pleistocene. Third, the general aspect of the fauna is 
quite similar to that of the British Crag (Pliocene). That the 
Deadman Island Pliocene belongs to the latter part of that 
epoch is evidenced by its fauna, which gradually grades into 
that of the typical Pleistocene through that of the overlying 
lower San Pedro (Pleistocene). The gap between the Deadman 
Island Pliocene and Pleistocene is distinct, though not wide. 
