CALIFORNIA. 167 



fying the climate, which is represented as tropical throughout the 

 year. This valley extends as far south as the San Bernardino Moun- 

 tain. The residents in California say that they have never known 

 the wind to blow from the northeast within thirty miles of the coast. 



This state of things may also prevail in the interior, and will natu- 

 rally prevent the cool stratum of air from descending into the valley, 

 it being carried to the interior by the prevailing winds from an 

 opposite quarter. 



In ordinary seasons these valleys are well watered by streams from 

 the mountains, which vary very much in size : they are for some part 

 of the year mere brooks, while during the rainy season, from No- 

 vember to February, they become in some cases impassable. The 

 Sacramento is the largest river in California. One of its branches, 

 Destruction river, takes its rise near Mount Shaste, and was examined 

 throughout the whole of its course by our land party, until it joined 

 the Sacramento : the latter is thought by some to pass through the 

 mountains and join Pitt's river. Pitt's river is said to take its rise to 

 the northeast of the Shaste Mountain, and from the information that I 

 received, extends as far as Pitt's Lake, under the forty-second parallel. 

 I have reason to doubt whether the length of its course is so great, and 

 believe that the Sacramento has its source in the eastern spurs of the 

 Shaste Mountain. I have, however, indicated by a dotted line on the 

 map, the course Pitt's river is thought to pursue before it joins the 

 Sacramento. This, if correct, would give the Sacramento, with its 

 branches, a course of two hundred miles from the ocean. 



The first branch of any size in descending the Sacramento is that 

 called Feather river, which joins it below the Prairie Butes, coming 

 from the northeast. This branch takes its rise in the California 

 Mountains, near their northern end, and has a course of about forty 

 miles. The American river is a small branch that joins the Sacra- 

 mento at New Helvetia. After receiving this stream, the Sacramento 

 is joined by the San Joachim, which courses from the south, and 

 below their confluence enters the bay of San Pablo through the straits 

 of Kacpaines, thence passing into the bay of San Francisco. 



It is navigable for boats to the distance of one hundred and fifty 

 miles, and for vessels as far as New Helvetia. The upper portion of it, 

 near the Prairie Butes, overflows its banks, and submerges the whole 

 of the Sacramento Valley as far down as the San Joachim. This 

 inundation is probably caused by the united effects of the Sacramento 



