TERTIARY FAUNAS OF THE PACIFIC COAST 529 
Pliocene occurs along the southwestern border of the San Joaquin 
Valley in western Fresno and Kings counties where the Tulare 
formation, largely of Pliocene age, attains a thickness of about 3,000 
feet. 
DIASTROPHISM AND VOLCANISM IN THE PLIOCENE 
The most important movements inaugurating the Pliocene seem 
to have been an elevation of the Sacramento Valley and certain por- 
tions of the coastal belt of northern 
California and Oregon and _ the 
closing of the connection between 
the south end of the San Joaquin 
Valley and the southern California 
province. Although sedimentation 
was practically continuous from the 
Pliocene into the lowest part of the 
Pleistocene over much of the Pacific 
Coast, there is in parts of southern 
California a sharp line of uncon- 
formity between the Pliocene and 
Pleistocene. The extreme localiza- 
tion of the movements producing 
this unconformity is well exemplified 
at San Pedro, near Los Angeles, 
where the Pleistocene is separated 
from the Pliocene by an angular 
unconformity at Deadman Island, 
while half a mile distant on the 
mainland the same formations are 
perfectly conformable. Volcanic 
activities of a more or less com- 
plicated nature took place in certain 
portions of northern and central 
California during the Pliocene, while 
in the same period and probably up 
Lecenn 
ar 
eee 
Puiocene : 
Raleh Arnola,\a0q 5 
Fic. 5.—Map showing hypothetical 
distribution of land and water on the 
Pacific Coast during Pliocene time. 
to a very recent date certain areas in the Sierra Nevada and Cascades 
have felt the effect of volcanism to a marked degree. 
