VALLEYS AND PLAINS—WATER COURSES. 
9 
westerly direction close under the former mountain. In its course this stream flows through 
a gorge for about twelve miles, separating the main valley into the upper or Santa Inez valley, 
and the lower or La Purisima, from the mission there located. These valleys have a com¬ 
bined length of fifty miles and an average width of four miles, and are hounded on the 
north by terraces sloping hack to low spurs jutting out from the mountains to the coast. The 
valleys and side slopes of the mountains and terraces are dotted with clumps of oaks, and the 
streams fringed with a growth of willow and cotton-wood. Leaving the Santa Inez, no valley 
is found until arriving at the mission of Santa Buenaventura, which is situated at the mouth of 
the valley of the same name, near the beach. This we crossed at right angles, but found, by 
side explorations, that it extends inland, and turning the east end of the Santa Inez mountain, 
heading with the Santa Inez river, receives the waters of the ocean slope of a lofty ridge, the 
extension of the Santa Lucia which separates this valley from the head of the Cuyama plain. 
Leaving the San Buenaventura, we enter upon the Santa Clara plain, which takes its name 
from the stream draining it. This plain extends from the beach, where its width is twenty miles, 
inland for forty miles, gradually narrowing as it is ascended, and contains nearly two hundred 
square miles. It heads in the Hew or Williamson’s Pass, and in a range of mountains behind the 
mission of San Fernando, and is joined in its course by several tributary valleys. It is separated 
from the San Fernando plain by the Santa Susana mountains, within which, however, lies a 
small valley, the Semi, apparently completely cut off from the plain on either side, but is a 
tributary of the Santa Clara, and from its location and extent affords an easy connecting link 
between the two plains. The San Fernando has an area of eighty-five square miles, hounded on 
the north by a high ridge or main axis of the Coast Range, on the west by Santa Susana, and 
separated from the ocean by a low rolling ridge, which extends for thirty miles to Los Angeles, 
where the stream which receives all the waters of the plain and surrounding slopes turns the 
ridge and hears off to the ocean at San Pedro.* Between Los Angeles and the coast, and adjacent 
to the stream above noted, there is spread out another smooth extent of prairie or meadow 
country containing about-square miles, the Los Angeles plain proper. To the east, and 
at the base of the mountains is found the mission of San Gabriel, located upon the foot slopes 
of the mountain range, and overlooking another large plain, hearing the name of the mission. 
These are simply local names and are all embodied under the general name of Los Angeles 
plains, embracing the champaign district lying at the base of the mountains between the 
missions of San Fernando and San Gabriel, and extending off to the shore line. But it must 
not be understood as one unbroken and continuous prairie surface. It is beautifully diversified 
with smooth knolls and low rolling ridges, with an occasional clump of oaks near the base of 
the mountains. 
Section 4. WATER COURSES. 
The Coast Range between the Bay of San Francisco and the plains of Los Angeles is drained 
by numerous small streams, which break from the canons and gorges, clear limpid mountain 
brooks, whose waters become turbid and sluggish as they meander through the lower valleys 
and plains, and are often entirely absorbed by the sands of their beds. In the mountainous 
districts these streams have narrow valleys and gorges while flowing parallel with the geological 
axis. But when these axes are crossed or ridges pierced the valleys become contracted, till 
finally the stream is hemmed in by lofty walls of rock approaching verticality, and flows over a 
bed of huge boulders, rendering the passage of these canons always difficult, and often 
impracticable. As soon as these streams debouch upon the plain districts their features undergo 
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