ITS RELATIONS TO ESTERO AND TULARE PLAINS. 
55 
The western boundary of the valley is the Santa Lucia range in its course south. This 
mountain ridge loses none of its height or power as a physical feature; at the northern edge 
of the plain its thickness is from 16 to 20 miles through where the river canons ; south of this, 
for 40 miles, there are no passes through it, presenting, as it does, a lofty range of sharply 
defined crests of height increasing southward, and uniting with the lofty land where the San 
Eafael and the Saint Inez mountains in their course blend together and form a hilly and almost 
impassable district in the northern part of Santa Barbara and Los Angeles counties. This 
range was not examined closely in its southern course ; the streams which rolled down carried 
as debris serpentine, massive and foliated, trappean and porphyritic jasper stones, transparent 
and hyalitic quartz, but no granitic pebbles ; nowhere along the range has there been the 
smallest trace of a granitoid rock observed ; and the sharp sky outlines of the range, when 
viewed from the valley, forbid the idea of its existence. 
Brown sandstones were observed flanking the slopes of this range at the northern end of the 
valley ; sufficient time was not afforded for exploring them for fossils, but in lithological char¬ 
acter they closely resembled the brown and yellow sandstones which clothe the same axis in the 
Santa Margarita valley, which lie beneath the layers of ostrea and are the superior beds of the 
gypsiferous and saline grits of Panza. These slope abruptly down to the valley bottom, and 
spreading in places out into long foot ranges, with their summits abraded smoothly so as to form 
an extended flat or terrace extending for several miles out toward the valley from the base of 
the main mass of mountain. 
The Santa Maria or Cuyama valley differs from any other observed in not having a true out¬ 
let. On the south it is shut up by the San Emilio mountain region ; on the east by the low 
porphyritic felspar range running into that mountain also ; on the north it is occluded by the 
cross ranges given off from the Santa Lucia, and by this range on its west, throughout the 
whole length ; it is completely shut in, except at the point where the river canons through the 
narrow gorges of the Santa Lucia. This is a channel which the river itself has partly cut for 
itself, and scarcely can be called the natural outlet of a plain. The slope of the base of the 
plain is to the north by west, and would naturally pour its waters into the small valleys of San 
Jose and Santa Margarita were it not prevented by the serpentine ridges crossing it at the head 
of these localities. The observer, ( first casting his eye over this extended plain, widening to¬ 
wards the south by the recession of the mountain ranges, would at once set it down as the basin 
of a great arm of the sea, which ran up toward the north, and that the natural debouche was 
toward the southeast, or opening into Tulare plain. This may have been the case once; but at 
such time Tulare plain itself was not so elevated or cut off from communication with the desert 
east as at present. The elevation of Tulare and Santa Maria were coeval. The sandstones and 
gypseous beds found northwest of the Canada de los Uvas may be traced round the sides of the 
porphyry domes into the Cuyama valley as a continuous series, elevated by the same local 
action ; and as the Estero plain lies between Tulare and Santa Maria valley, upon the crests or 
in a trough between the porphyry ranges, the continuation of the San Jose range, which also 
stretches under Panza and Cariso, that plain (Estero) belongs to the same age, and the San 
Jose range, by its elevation, separated for the first time the previously connected plains of 
Cuyama and Tulare valley. 
Whichever may have been the original outlet, which at present is closed up, it is, perhaps, 
difficult to decide now ; but the valley everywhere, especially at the lower end, (north,) presents 
the usual marks of running water in the terraces found on its mountain sides, and on such a 
