SANDSTONE OF BENICIA AND MARTINEZ-LIVERMORE’S VALLEY. 
5 
exposure, and some seams of gypsum were found. At a quarry a short distance from the point, 
several blocks of soft sandstone were found to contain impressions of the stems of plants, some 
of them in the form of lignite; hut they are not sufficiently well preserved to be identified. 
Martinez, July 10.—Left Benicia and crossed the straits ot Carquines to Martinez, a small 
town directly opposite. The hill-slopes on this side of the straits are tolerably well wooded 
with an evergreen oak, thus contrasting strongly with the barren slopes of the Benicia side. 
The trees are, however, principally confined to the valleys or depressions of the hill-sides, and 
do not obscure the outlines of the hills, which are beautifully curvilinear. The town is built 
on a nearly level plain, between two ranges of hills, and our first camp was upon this plain, on 
the banks of a small brook. In the channel of this stream, an outcrop of sandstone, similar to 
that at Benicia, was observed. Its trend was northwest and southeast, approximately. 
The geological formations of Benicia and Martinez appear to be similar; Martinez is under¬ 
laid by sandstone strata resembling those of Navy Point, and they may be regarded as the con¬ 
tinuation of the same series. The trend or direction of the strata is the same on both sides of 
the straits, and it indicates that the current has cut its channel by denudation alone, without 
the aid of any great dislocation or disturbance of the strata. This similarity of composition and 
direction of the strata on the opposite sides of the straits was also observed by Mr. P. T. Tyson, 
and noticed in his report. 1 
This was our first camp in the open air, without tents. The remarkable brilliancy of the 
stars throughout the night, and the absence of clouds or dew, could not but be observed, 
especially by those unaccustomed to the climate. The heavens were as brilliant as in the clear 
frosty nights of mid-winter in New England. The strange and peculiar yelping and howling 
of the coyote, or California wolf, was heard for the first time. They came very near the camp 
on all sides, and one animal seemed indefinitely multiplied, so various and involved were the 
sounds. 
Martinez to Livermore’s Pass, 44 miles, July 11-16.—The mules were brought into use for 
the first time, and the line of survey was commenced. We passed southward by a good road 
winding among the smooth round hills. Fine farms were seen, well-fenced, and giving evi¬ 
dence, in the abundance and richness of the crops, of the great depth and fertility of the soil. 
The high peak of Mount Diablo was constantly visible beyond the hills on our left, and several 
miles distant. It also formed a prominent feature in the landscape at Benicia, and is visible 
1 Senate Ex. Doc. No. 47, 31st Cong., 1st sess., 1850, p. 16. 
