SANTA CLARA VALLEY : TOPOGRAPHY. 3 
Santa Susana Mountains, lie between this valley and the minor 
depression of the Simi. The San Gabriel Range attains its maxi¬ 
mum altitude at 10,080 feet in San Antonio Peak, in the eastern 
portion of the uplift. The highest peak in the Santa Susana Moun¬ 
tains reaches 3,756 feet. Oak Ridge and South Mountain rise to 
maximum elevations of 3,000 and 2,258 feet, respectively. 
The Santa Clara receives its principal streams from the north. 
Named from east to west, these are: Castac, Piru, Sespe, and Santa 
Paula creeks. The courses of these streams are most tortuous, their 
loci having been determined in part by structure, in part by erosion. 
Their canyons are deep, sharply cut, and in many places cliff bound 
and inaccessible. In addition, there is a well-distributed and dense 
growth of chaparral. Sespe and Santa Paula creeks carry compara¬ 
tively* large amounts of water throughout their length. Piru Creek 
is a somewhat smaller stream, but is sufficient for the irrigation of 
the fertile lands which border its lower course to a width of a mile 
or more on either side. The Castac Valley is practically dry. 
The Ojai Valley, an intermontane depression which evidently had 
its origin in a system of profound faults, but whose aspect has since 
been modified by erosion of the strata over the area of excessive dis¬ 
turbance, lies some distance north of the lower part of the Santa Clara 
Valley, yet from a geologic standpoint it is a part of the general area 
here considered. The trend of the valley is east and west; its length 
is about 12 miles, and its width from 2 to 3 miles. The drainage 
is now chiefly to the west, San Antonio Creek flowing through it 
and joining Ventura River, a stream of considerable size, which 
flows thence 10 miles to the south, entering the Pacific at the town of 
Ventura, not far from the mouth of the Santa Clara. At the eastern 
edge of Ojai Valley, however, a minimum of the drainage passes into 
Sisar Creek, which discharges into Santa Paula Creek. Midway of its 
length a low ridge divides the depression into two parts, known as the 
upper and lower valleys. The altitude of the upper valley ranges 
from 1,250 feet at its western extremity to 1,500 feet at its eastern; 
that of the lower valley from 750 to 1,000 feet. Ojai Valley is well 
watered from natural streams and wells. A few miles up Matilija 
Creek are noted hot springs that are reported to have remarkable 
healing powers. 
North of Ojai Valley is the Topatopa Range, 7,000 feet in altitude; 
on the south is Sulphur Mountain, 2,750 feet. The mountainous 
country north of the valley can be reached only by trails, and although 
the distance across it to the San Joaquin Valley is but 36 miles, the 
region is one of the least accessible in the United States. Sulphur 
Mountain presents a steep northern face little indented with canyons; 
its southern slope, however, has been severely scarred by erosion, but 
is traversed by canyon roads. (See PI. II.) 
