3'i EESOUKCES OF CALIFORNIA. 



and the same difference is observed between Nevada and Mar 

 rysville, wliich bear similar relations of distance and elevation 

 to each otlier. 



The statistics given in the preceding part of this section 

 relative to the amount of rain-fall at San Francisco, are intend- 

 ed to represent ordinary years, such as all those between 1847 

 and 1860. But the winter of 1861-62 proved to be an ex- 

 traordinary season, the amount of rain being double that which 

 has fallen in any other winter since the American conquest. 

 The average rain-fiill during the winter months at San Fran- 

 cisco is about 12 inches; whereas, between the 1st of Novem- 

 ber, 1861, and the 1st of February, 1862, 37 inches fell in San 

 Francisco, and during the same period 101 mches fell in So- 

 nera, Tuolumne county. During the four months from the 1st 

 of November, 1861, to the 28th of February, 1862, inclusive, 

 45.53 inches of rain fell in San Francisco, viz. : 4.10 in Novem- 

 ber ; 9.54 in December ; 24.36 in January ; and 7.53 in Feb- 

 ruary. This rain caused a great flood, which did much damage 

 along most of the rivers, and especially in the Sacramento 

 Basin, where Sacramento City, Stockton, Marysville, and nu- 

 merous minor towns, were completely inundated, and the 

 whole central part of the basin, including an area one hundred 

 and fifty miles long and twenty miles wide, was converted 

 into a great lake, which covered the land to a depth varying 

 from two to ten feet for more than a month. The long dura- 

 tion of the flood, its great height, and the vast damage which 

 it did, will render it an epoch in the history of the state, and 

 make it well worthy of study, especially so for as relates to 

 the Sacramento Basin, where the most serious injury was done 

 — that basin extending north and south from Mount Shasta to 

 the Tejon Pass, a distance of four hundred and flky miles ; and 

 east and west from the summit of the Coast Range to that of 

 the Sierra Nevada, a distance of one hundred miles. These 

 two ranges unite at the two ends of the basin, w^hich has its 

 outlet in the middle, where the Sacramento from the north and 

 the San Joaquin from the south, having united their waters in 



