26 GENERAL DESCRIPTION OF THE REGIONS EXAMINED. 



SACRAMENTO VALLEY. 



No complete description of this valley will be attempted, as its general character is well 

 known, and as Lieutenant Williamson, in his Railroad Eeport, has fully discussed its topo- 

 graphical features. A few remarks, however, relating to its climate and productions, may not 

 be 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 Fab., 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 bottest months of the year, is to be expected in this 

 valley. The result can be 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 

 back 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 witb 

 luxuriant vegetation ; but the excess of rain often causes the streams to overflow their banks, 

 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 



