TERTIARY STRATA—FOSSILS—LOS ANGELES RIVER. 
73 
SAN FERNANDO PASS. 
October 30.—We moved to tlie east, and found the trail leading to the pass. A fine brook 
flows in the foot-hills, and an inviting camping-ground was passed, where we should have rested 
during the preceding night. Plane trees and the evergreen oaks grew here in abundance, and 
one of the men found a quantity of small walnuts, similar in every respect, except size, to the 
ordinary, round English walnut. 
The border of this brook was evidently a favorite camping place, and had been much used. 
Crosses were cut deeply in the trunks of the trees, and some of them were, doubtless, the work 
of the Fathers many years ago. Among various inscriptions cut in the smooth hark of the large 
plane trees was one by Joaquin, the much-dreaded bandit and assassin. 
This pass is hardly worthy of the name, for it consists of a steep ascent and descent over the 
range of hills known at the locality as the Susannah Range. The ascent from the north is not 
so abrupt as the descent on the opposite side, which, in some places, becomes nearly vertical, 
and is not passable for wagons without the aid of ropes. The summit level was found to he less 
than two thousand feet above the sea, and about six hundred feet above the general level of the 
plain of the San Francisquito rancho. 
Sandstone formation , probably Tertiary .—The only rocks visible in this pass were stratified 
sands and clays ; in some places forming firm, compact strata, and in others appearing soft and 
crumbling. These strata are unlifted, and their edges are well exposed by deep ravines that 
have been cut by running water. When these exposed edges were viewed from different points 
along the trail, they had the appearance of dipping in various directions, and several contradic¬ 
tory results were obtained. It was, however, very plain that the hills had long slopes towards 
the north or northwest, and that in the opposite direction they presented bold bluffs or escarp¬ 
ments; I therefore concluded that the prevailing dip on the north side of the summit was 
northward, and that the trend of the flexure was a little north of west and south of east. It is 
probable, also, that this range is formed by an anticlinal axis of the strata; but the transit was 
made so hurriedly that it was impossible to give the dips a careful and full examination. The 
long and gentle slopes towards the north were sparsely wooded with oak trees, but the escarp¬ 
ments were barren, or only covered with tufts of grass, then parched and dry. 
After reaching the summit, it was a difficult operation to get the wagon down the hill, for it 
was so steep that it was almost impossible to descend on foot without passing to and fro in 
diagonal lines. If it ever becomes necessary to build a railroad at this place, the hills must be 
tunnelled or cut through. The only rock that will be encountered is the sandstone, and much 
of it is soft and can be removed by the pickaxe, and it is probable that very little blasting will 
be necessary. 
Fossils .—A short distance beyond the base of this steep hill, I found a boulder of sandstone 
in the bed of the creek, containing fossils, which were but partly preserved, the greater portion 
of the lime having been removed, so that neither the shells nor casts were left in a perfect state. 
The specimens obtained were sent to Mr. Conrad for description, but their specific characters 
were too indistinct for determination. 
They are of the genera Ostrea, Pecten , and Turritella, and show that the formation is Tertiary. 
Late in the evening we encamped under some trees by the side of the creek that flows from 
the pass, and is one of the tributaries of the Rio de los Angeles. The ground appeared to have 
been cultivated ; and in the morning we found that we were under fig trees, and by the side of a 
10 F 
