10 GEOLOGY. 
of weeds. But on close inspection of the bare surface, the grains of oats could be perceived 
scattered about, or collected in little depressions, sheltered from the wind, The fire, it seems, 
is not hot and lasting enough to accomplish more than the separation of the kernel from the 
husk; perhaps parching its surface or hull. In this condition, it is fitted to fall into the cracks 
of the soil, and thus be entombed in readiness to spring up after the first shower of winter, or 
to afford sustenance to birds and bands of deer or elk. That it is sought and eaten by deer 
while in this state I had full evidence, for I came upon a herd quietly feeding on a spot, which, 
at a distance, seemed to be only the bare and blackened earth. 
In the endeavor to cross back to the valley of the Pass, without retracing my steps, I mounted 
to the summits of several of the hills. On nearly all sides there seemed to be no limit to their 
succession ; one rounded outline was seen beyond another far into the distance, and all were of 
the same brown or yellow hue, without a green tree or shrub. But looking eastward, towards 
the San Joaquin, a far different view was presented. There lay outstretched the broad and green 
Tulares—great swamps or lowlands overgrown with rushes and threaded by the sinuous channels 
and sloughs of the river. The further margin was hid in the smoky distance, but this served 
to increase rather than diminsh the conception of the great extent of this alluvial tract. 
We encamped at a place called Elkhorn, consisting of one or two rudely constructed houses, 
at the base of the low hills on the east side of the range. "The place probably derives its name 
from the number of the antlers of the elk found here and among the surrounding hills. In this 
vicinity several thick beds ot drift-gravel and rounded boulders, six, eight, and ten inches in 
diameter, were observed. During the night we experienced a violent wind, which became a gale 
towards morning, and we were glad to roll up our blankets and put on overcoats, the morning 
was so cold. 
Elkhorn to Grayson’s ferry, San Joaquin river, July 18, 30 miles. —We again turned south- 
ward, and travelled between the base of the Diablo range and the left margin of the marshes 
and tulares of the San Joaquin river. For the greater part of the distance the surface is nearly 
level, and is almost a desert plain, consisting of gravel and pebbles brought down from the 
hills. Some of the streams that descend from the Diablo range excavate wide and shallow 
gullies in the plain, and leave them strewn with rounded boulders of various sizes. At this 
season these gullies are without water. All this portion of the route is admirably adapted to 
the construction of a railroad. The gravel will form durable embankments, and can be readily 
excavated, but no cuttings will be required. 
The mountains of the Diablo range were constantly visible on our right, and here and there 
a distinct outerop of sandstone could be seen, the dip generally appearing to be southwest. A 
part of the surface of the plain was covered with a growth of sunflower, standing from six to 
ten feet high, and the blossoms very small. 
The lower part of the San Joaquin river is bordered by numerous sloughs, and winds about 
through low marshy ground, covered with rushes and willows. Such portions of these marshes 
as are only temporarily overflowed, during the winter months, support a growth of coarse grass 
and other plants. In some places along the margin of these sloughs the soil is fine and deep. 
It appears rich in the inorganic constituents of plants, but is deficient in organic materials, 
The number and intricacy of the winding sloughs and channels that traverse this wide area of 
low marshy land is worthy of notice. They are well shown upon the general map. The whole 
included area may be regarded as the alluvium of the Sacramento and San Joaquin rivers, and 
as an extensive interior delta, 
