26 
GENERAL DESCRIPTION OF THE REGIONS EXAMINED. 
SACRAMENTO VALLEY. 
No complete description of this valley will he attempted, as its general character is well 
known, and as Lieutenant Williamson, in his Railroad Report, has fully discussed its topo¬ 
graphical features. A few remarks, however, relating to its climate and productions, may not 
he out of place. 
Sheltered by the Coast Range of mountains from the moist and cool sea breezes, which render 
the summer climate of the sea-shore of northern California so delightful, much of the Sacra¬ 
mento valley is parched with excessive heat in the dry season. From the Army Meteorological 
Register, it appears that, at Benicia, where the influence of the sea breeze is felt, the mean 
summer temperature, for the years 1852, ’53, ’54, was 66°.3 Fah., while at Fort Reading, 
which is about two degrees of latitude further north, it was ’79°.6 Fah., for the same years. 
Even at San Diego, situated seven degrees of latitude south of Fort Reading, the mean summer 
temperature was only 70°.9 Fah., for the above mentioned years. 
The effect of this excessively high summer temperature is greatly increased by the want of 
rain. Very little falls during the months of June, July, August, September, and October. 
The mean fall, during these five months, for the years 1852, ’53, ’54, was 1.1 inches at Benicia, 
and 1.4 inches at Fort Reading. This tends to show that less than three-tenths of an inch of 
rain per month, for the five consecutive hottest months of the year, is to he expected in this 
valley. The result can he easily anticipated. Vegetation, except on the banks of the streams, 
is in a great measure destroyed, and the foliage of the trees furnishes almost the only green 
upon which the eye of the traveller can rest, when wearied with the glare of the sun, reflected 
hack from the whitened plains. 
During the rainy months, which are December, January, February, March, and April, the 
average fall is between 3 and 4 inches per month. The whole region is then clothed with 
luxuriant vegetation ; hut the excess of rain often causes the streams to overflow their hanks, 
and spread far and wide over the low lands. Much of this water remains stagnant, until 
evaporated by the heat of the sun, which is undoubtedly one of the causes that render inter¬ 
mittent fever so great a scourge of the valley. 
Notwithstanding this unfavorable climate, the richness and fertility of the soil well repay 
the farmer for his labor ; and fine crops of barley, wheat, oats, potatoes, onions, &c., can be 
easily raised. A luxuriant growth of wild oats covers a large portion of the valley, and gives 
it an appearance of high cultivation. Grapes, which are a natural product, are also one of 
the very important staples of the region. The forest trees, which, in the valley, are confined 
to the banks of the streams, are chiefly oaks, sycamores, and cotton-woods. The foot hills 
of the Sierra Nevada are densely timbered with various species of oaks, pines, and firs. 
PIT RIVER AND ITS TRIBUTARIES. 
In 1849, Lieutenant Williamson accompanied Captain W. H. Warner, United States Topo¬ 
graphical Engineers, on his ill-fated expedition to the sources of Pit river. As this was the 
only survey of this region which has ever been made, and as its results were never fully 
published, Lieutenant Williamson proposed to give a synopsis of them in this report. I have, 
therefore, compiled from his original field notes the following very brief description of the 
upper portion of Pit river. 
A short distance above camp 23, where, in 1855, the party left Pit river, the stream passes 
