VALLEYS AND PLAINS. 
7 
extent. From Points Arguello and Concepcion this ridge trends off to the east, impinging 
upon the preceding ones, and terminates abruptly at the valley of the Rio San 7 Buenaventura. 
For seventy-two miles to the east of Point Concepcion the shore line follows closely the direction 
of this ridge, the foot hills sloping down to a grassy terrace which bluffs down step-like from 60 
to 100 feet to the alternating rock and sand beach. Opposite Santa Barbara these mountains take 
the name of that town. Below this point there is a gradual divergence of the shore line and the 
main ridge, and a secondary and minor ridge intervening, continues to San Buenaventura, with 
its precipitous faces sloping down to the water’s edge ; so that the traveller is forced for a few 
miles to take the beach, and to conform his motions to those of the tide. Besides these prin¬ 
cipal mountains, there are others of secondary importance, and these retain generally the same 
feature of parallelism, although apparently trending more to the east. They give the 
country in many places a rolling, and in others a terraced appearance. Of the latter ridges, 
the most important are the Sierras de la Santa Susana and de la Monica, lying between the 
Santa Clara and Los Angeles plains. 
Section 3. VALLEYS AND PLAINS. 
Proceeding from Martinez, (on the Straits of Carquinez, opposite Benicia,) we traversed in 
order the following plains and valleys : 
Between Monte Diablo and a secondary ridge, forming the eastern boundary of the Bay of 
San Francisco, lies the beautiful and inviting valley of San Ramon, extending inward about ten 
miles, where it opens out into a plain, headed by the foot hills and spurs of the two bounding 
ridges which unite beyond. This valley has an average width of two miles, and is drained by 
a stream, Arroyo de los Nueces, flowing into the Suisun Bay. The waters of Livermore’s plain 
at its head form a stream, the Alameda, which breaks through the secondary ridge on the west 
and empties into the Bay of San Francisco, near its southern end. The divide between these 
two streams is not marked by a decided or distinct ridge, but is found on a smooth plain 
surface, where, without the aid of instruments, it would be difficult, if not impossible, to trace 
it. This feature is not confined to this locality alone ; it was observed also in the Santa Clara 
valley, in the divide between the drainage towards San Francisco and Monterey Bays. On 
either side of the southern arm of the Bay of San Francisco are smooth plains or meadows, 
sloping from the bases of the bounding ridges gently down to the water’s edge. These plains 
unite and surround the head of the bay, giving at San Jose a total width of eight miles, and 
thence extend in an unbroken valley between the Monte Diablo ridge and Santa Cruz mountains 
to a distance of over sixty miles on a prolongation of the axis of the bay. This entire valley is 
known by the general name of Santa Clara, whilst that portion enveloping the head of the bay 
retains the name of the pueblo or town, San Jose. From the mountains on either side there 
are several small streams flowing down towards the bay, but the valley proper is drained by 
the Coyote and Guadalupe creeks, flowing into the Bay of San Francisco, and the Pajaro and 
its tributaries into that of Monterey. Between the headwaters of the streams of these two bays 
is the divide similar to the one before mentioned. Beyond this, the main tributary of the 
Pajaro has its source, at the head of the valley to the south of the Pacheco and Santa Ana 
peaks. This stream breaks through towards the coast, receiving the drainage from a second 
plain or valley, that of the San Juan Bautista, lying at the base of the Gavilan. 
The Pajaro, by a narrow valley, pierces the ridge, or rather flows between the terminal spurs 
of the Santa Cruz mountains on the north, and of the Gavilan mountains on the south. When 
