CHAPTER XVIII. 
Rio San Joaquim and Valley.—Rio Sacramento and Valley. 
Rio San Joaquim.—The most interesting portion of Upper 
California in many respects, is the upper or northern, em¬ 
bracing the Bay of San Francisco, its tributaries, the Sacra¬ 
mento, San Joaquim, and Jesus Maria rivers, and the country 
bordering on these waters. 
The Rio San Joaquim rises in a lake called Buenavista, 
situated in Latitude 36° N., and about three hundred miles 
northwest of the mouth of the Colorado; and running in a 
northwesterly course nearly six hundred miles, falls into tide¬ 
waters at the eastern extremity of the Bay of San Francisco. 
This stream has a deep and tranquil current. Its waters are 
transparent and well stocked with salmon and other fish. It 
is navigable for small steamboats, about two hundred and 
fifty miles. A high range of mountains on the northeast, at 
an average distance of forty miles from the river, bounds its 
valley in that direction : and a range of hills, rather low, in 
the north, but becoming lofty in the south, bounds it on the 
west, forming a prairie vale six hundred miles in length; 
nowhere less than forty, and often more than one hundred, 
miles in width. This vast plain extends indeed with little 
interruption, from the Bay of San Francisco to the Colorado, 
gradually growing wider and wider, and more uneven in its 
surface, till it reaches that river. A space sufficient for an 
empire ! A very large proportion of its surface is open prai¬ 
rie, covered with grasses and a species of wild oats. But it is 
so diversified by lines of trees skirting the streams, by wooded 
spots, standing out like islands on the green plain, by arms 
of timber stretching far down from the mountain side$, and 
