CHAPTER XIII 
TERTIARY FORMATIONS OE OCOYA CREEK, MONTEREY, AND OTHER 
LOCALITIES. 
Eocene formations at the head of the tulare valley.—Eocene fossils.—Ocoya creek tertiary.—Extent of the formation.— 
Soft clay-hills.—Absence of vegetation.—Steep slopes.—Lithological characters.—Pdmice-stone and volcanic ashes.— 
Section of the strata.—Charcoal.—Deposition of oxide of iron by infiltration.—Formation of gypsum.—Resemblance of 
THE LINES OF OXIDE OF IRON TO THOSE PRODUCED IN STRATA BY PRESSURE.—FOSSILS.—SHELLS.—SHARK’S TEETH—MASTODON.—SlLICI- 
fied wood.—Evidences of shallow water and currents at the time of the deposition of the fossils.—Resemblance to a 
BEACH ACCUMULATION.—PROBABLE MIOCENE AGE OF THE DEPOSITS.—FORMER EXISTENCE OF VOLCANOES IN THE SIERRA NEVADA.-TER¬ 
TIARY OF CARRIZO CREEK AND THE COLORADO DESERT.-LITHOLOGICAL CHARACTERS.—CONCRETIONS.—PEBBLY DRIFT ALONG THE COLO¬ 
RADO ano gila.—Miocene fossils.—Tertiary of ban diego.—Trap-dyke.—Fossils.—Tertiary of the bernardino sierra and 
SAN FERNANDO.-STRATA OF LOS ANGELES AND SAN PEDRO.-FOSSILS.-TERTIARY AT MONTEREY.—LITHOLOGICAL CHARACTERS.—INFU¬ 
SORIAL beds.—Fossil shells.—Foraminifera.—Tertiary of the southern end of the great basin.—Silicified stems.—Post 
PLIOCENE DEPOSITS OF MONTEREY, SAN PEDRO, AND SAN DIEGO.-RECENT ELEVATION OF THE COAST.-GENERAL OBSERVATIONS ON THE 
TERTIARY FORMATIONS.—MlOCENE AT THE BASE OF THE SIERRA NEVADA.—COMPARISONS. 
EOCENE OF THE SOUTHERN END OF THE TULARE VALLEY. 
The mountains at the southern end of the Tulare valley have a central axis of granitic 
and metamorphic rocks, which, form the high ridges and peaks ; but the lower ridges on the 
north side consist of thick strata of sandstone and conglomerate, upraised at various angles, 
but generally dipping away from the granite or towards the valley. The strata appear to form 
a succession of escarpments facing the granite, as shown in the annexed section. 
IDEAL SECTION AT THE HEAD OF THE. TULARE VALLEY. 
All the dips which were observed were towards the north ; there was, however, but little 
opportunity for a general exploration, and reverse dips may be found at other points than those 
visited. A sketch of one of the exposures near the pass of San Amedio is given in the Itinerary, 
page 45, and shows the general appearance of the strata where they are cut through by a valley 
across their trend. The strata, at the point’ represented in the sketch, were very regular, and 
chiefly argillaceous sandstone, with coarser materials at the bottom ; a thick stratum of con¬ 
glomerate being exposed in an adjoining outcrop. The thickness of the series of beds exposed 
at this point is probably not less than 2,000 feet. 
No fossils were visible at that place ; but several miles east, at the entrance to the Canada de 
las Uvas, a boulder of sandstone full of fossils was dicovered among the drift, which, had ap¬ 
parently been brought out of the Canada by floods along the bed of the brook. This boulder 
waS of a compact sandstone, of a brownish-gray color, and so filled with shells that it could 
