12 SAN JOAQUIN VALLEY. 
timber, and in the spring covered with a luxuriant growth of wild oats. As the season 
advances, the rain ceases, and the burning sun converts the once green hills into barren-looking 
mounds. These hills are rounded, and so symmetrical as to give them an artificial appearance. 
The three following days were consumed in making a survey of the pass. The spring-wagon 
was taken to carry the odometer, and the courses were taken with a prismatic compass, on a 
small tripod, while at every prominent point a reading of the barometer was taken. We found 
the entrance to the pass to be 481 feet above the level of the sea, and its summit 686 feet, while 
the altitude of the eastern base of the hills was but 89 feet. This gave a grade of about 60 
feet in ascending from the west, and 87 feet in descending towards the east. "There would be 
little difficulty in winding, and thus increasing this distance, to reduce those grades, should it 
be desirable. Upon reaching the summit, the wagon-road does not at once cross and commence 
the descent, but continues to ascend more than 200 feet more, in order to find better ground 
for wheeled vehicles. If it were desired to construct a railroad over these hills, I have little 
doubt that a proper examination would result in the discovery of much better places than this 
pass, although this is determined to be practicable. The rounded hills interlocking, cause the 
road to be exceedingly tortuóus, and it would require a great deal of excavation and embank- 
ment to make curves with a sufficiently large radius. 
SAN JOAQUIN VALLEY. 
On the 17th we left camp early, and went through the pass with the wagons without much 
difficulty, and camped at the eastern base of the hills, near a solitary house, which is known as 
Elkhorn post office. From here we had, to the east, the broad expanse of the San Joaquin 
valley. The river had overflowed its banks, and the valley was one vast sheet of water, from 
25 to 30 miles broad, and approaching within four to five miles of the hills. It had been my 
intention to cross at the lower ferry and follow up the eastern side of the valley ; but this was 
evidently impossible. The first point on the river which presents banks high enough to pre- 
.vent an overflow is at Grayson, one of the cities of California, which looks very well on paper, 
but in which there are but two houses at present. It is two or three miles above the mouth of 
the Tuolumne river, the principal branch of the San Joaquin, and 27 miles southeast of 
Elkhorn. About a mile above Grayson a ferry has been established, and here we crossed with 
our teams and animals, (the work of a whole day,) and camped on the Tuolumne, five or six 
miles from its mouth. 
This river, as indeed are all the rivers flowing into the San Joaquin and the lakes, is fringed 
with trees. In the summer and autumn, when the water is low, these trees are 20 and 30 feet 
above the river; but in the spring, when the snow melts, the waters rise very rapidly, and often 
overflow their roots. Extensive side-channels or ‘‘sloughs’’ are thus formed, and these are 
most numerous near the mouths of the streams. On this account permanent bridges crossing 
these streams must be much longer than otherwise. There is no difficulty in finding good 
points for crossing. The Tuolumne would require a bridge from 200 to 300 feet. We followed 
up this river for 25 miles, when we struck the ordinary wagon-road, and thence proceeded to 
Fort Miller, a military post on the San Joaquin, in the foot-hills of the Sierra Nevada. As 
there is no doubt of the practicability of constructing a railroad to the extreme head of the 
Tulare valley, I do not think it expedient to enter into a detailed description of this vast plain, 
but refer to the few remarks at the commencement of this report, and the maps and tables 
accompanying it, for such geographical and topographical information as may be required. 
