268 GUIDEBOOK OF THE WESTERN UNITED STATES 
terials are well exposed in gullies and banks in the adjoining hill 
slopes. ‘Together with underlying deposits of Pliocene age they con- 
stitute the wide ridge of badlands on the south separating San Timoteo 
Canyon and San Jacinto Valley. The materials here are mostly 
coarse sand and cobble beds in a matrix of sand, underlain by soft 
sandstones and shales of gray-brown, yellow, and reddish tints. The 
structure of the ridge is strongly anticlinal, the beds on the north side 
and center dipping northeast and those on the south side dipping 
southwest into the Moreno-San Jacinto Valley. The axis of the anti- 
cline is some distance south of the crest of the ridge. It is covered 
by valley fill in slopes 20 miles west of Beaumont, but its extension 
to the northwest is shown in Bunker Hill and other outcrops to the 
northeast. Some features of the steeply dipping beds are shown in 
Plate 43. There are fine exposures of them on the highway that 
crosses the ridge 3 miles west of Beaumont. The strata forming this 
ridge, especially the lower members, contain many bones of extinct 
animals, comprising camels, a large and a medium-sized horse, ground 
sloth, tortoise, peccary, antelope, saber-tooth tiger, mastodon, rabbit, 
bear, and others—an assemblage of late Pliocene and early Pleistocene 
time, creatures mostly very different from the present fauna. (Frick.) 
It is believed that in late Phocene time southern California had 
somewhat the same configuration as at present. The land was gradu- 
ally rising, and on the narrow coastal margin was deposited a thick 
succession of marine beds. Much of the material was sand and clay 
of local origin. The animals were an assemblage of forms that would 
now look strange in this region. In the open meadows were droves 
of slender-limbed horses, various kinds of camels, including two of 
giant size, and many antelope and deer. In the brush were pigs, the 
large boar, and tapirs, and in the forest were saber-toothed tigers, 
ground sloths, wolves, and bears larger than the great Kodiak bear 
of Alaska. From the time of deposition of the lower sediments to 
that of the upper ones, there was considerable change in the fauna 
and the horses especially became larger and of a more advanced 
type. It is estimated that this was considerably more than a million 
years ago. (Frick.) 
The Tertiary and overlying formations lying on the granite south 
of Beaumont and extending westward nearly to Riverside have a 
total thickness of more than 4,000 feet. At the bese is about 1,800 
feet of red conglomerate and sandstone, unconformably overlain by 
about 1,500 feet of sandstone and shale, all of late Tertiary age. The 
lower beds are well exposed along Potrero Creek and its tributaries, 
south of Beaumont. (Frick.) 
___ The uplift and flexing of the strata in the ridge south of San Timoteo 
_ Canyon were geologically recent, probably contemporaneous with 
