HANNIBAL: A PLIOCENE FLORA FROM CALIFORNIA 333 
and about Evergreen and Los Gatos in the Santa Clara Valley 
now reach an elevation of 1,200 to 1,500 feet." 
The unconformable deposition of the valley alluvium upon 
the Santa Clara has taken place more or less continuously since 
the close of the Sierran epoch. At Madrone, as an alluvial fan 
of the Coyote River, it reaches the maximum elevation of 345 feet.” 
At least a portion of the alluvium must be referred to the Quater- 
nary from the presence of mammal remains characteristic of that 
age in gravels near Mountain View." Hence it must not be 
assumed that the Sierran epoch, though a very long period, was 
coincident with the entire Quaternary. 
The latest event, and a purely local one, has been the sinking 
of the San Francisco Bay region, causing a flooding of the Golden 
Gate River system by the tides. As a result the Santa Clara 
sediments reach an elevation of not more than 500 feet at Mission 
San Jose, north of that point they largely disappear beneath the 
later alluvium. 
AGE OF THE FORMATION 
The Santa Clara formation may be regarded as having been 
deposited during late Pliocene time. It occupies an unconform- 
able position upon the Purisima, a marine formation of older 
Pliocene age. It contains a molluscan fauna of which two-thirds 
of the species are still living. The strata were intensely elevated 
and eroded subsequent to their deposition, during the Sierran 
epoch, early Quaternary. 
The Santa Clara is presumed to be contemporaneous with the 
Deadman Islands formation of San Pedro Harbor, Santa Monica 
Cafion, and Packard’s Hill, Santa Barbara, a marine deposit 
occupying an analogous stratigraphic position in southern Calif- 
ornia. 
LOCALITIES WHERE PLANTS WERE OBTAINED 
Plant remains are abundant almost everywhere in the Santa 
Clara formation, but recognizable material has been obtained 
1 In the vicinity of Bird Creek, near Hollister, the beds, in a disturbed condition, 
reach an elevation of 1800 or 1900 feet. This is probably produced by local condi- 
tions, due to the proximity of the San Andreas fault, along which the earthquake of 
1906 took place. 
122 Branner, J.C. Jour. Geol. 15:3. 1907. 
13 Santa Cruz Folio, U. S. Geol. Surv. 1909: 6. 
