SOUTHERN CALIFORNIA. 83 



of water on this desert plain, is to be noted in that singular feature, to which the name of 

 " New River" has been applied by the Californiaa emigrants. 



The idea naturally conveyed by this name is that of a running stream, arising in the desert 

 and flowing towards the Colorado river, but its true character is quite the reverse ; the current 

 itself, which is by no means constant and at all times irregular, is in the opposite direction, or 

 from the Colorado, while its bed, instead of exhibiting the features of a regularly washed stream 

 bank, shows only a chain of lagoons or marshes irregularly connected, and often spreading over 

 extensive tracts, or at other times contracted within narrow beds. Its novelty, moreover, is 

 sufficiently disproved by the presence of heavy mezquite growth, and other plants and shrubbery 

 usually associated with the presence of water in this region. Indeed, all the singular features 

 in the case are now sufficiently accounted for, in the ascertained fact (first suggested by Major 

 Emory from barometric observations) of the existence of a natural depression, at this point, 

 below the level of the Colorado river at high water. The connexion between the overflow of the 

 one and the appearance of the other has been frequently observed, though the exact course of 

 this connexion has not yet been traced out. Still, all the facts in the case derive their full 

 explanation by referring it to this peculiarity of the Colorado river, which, seeking an outlet 

 for its swollen waters, spreads them in fertilizing deposits to such a great distance from its 

 usual bed. 



• LAKES AND LAGOONS. 



Mountain lakes are of very rare occurrence in any part of the region under examination. 

 The only body of water that I am acquainted with really deserving the name of a lake, is found 

 on the western slope of the mountains, near the parallel of 33° 30' north latitude, and some 

 twenty-five miles distant from the ocean. It is about five miles long, by from two to four in 

 breadth. It has no outlet, and its waters are consequently brackish. It is also apparently 

 shallow, and exhibits along its banks marks of recent and continuous recession, plainly indi- 

 cating a gradual exsiccating process. What adds to the interest of this latter fact, is the 

 explanation it seems to offer of the original condition of some of the more fertile basin valleys, 

 which exhibit all the characters of a lacustrine origin, to which they now owe, in a great 

 measure, their fertility. A fine example of this may be noticed in the rich and extensive valley 

 known as the San Bernardino. It is seen encircled by high mountains on all sides, and seems 

 to have derived its subsequent drainage by the Santa Anna river, which is now observed passing 

 through an elevated range of tertiary mountains towards the ocean. 



On the desert plain of the eastern side of the mountains, report speaks of one or more 

 extensive salt lakes, but no opportunity was aflbrded for a personal examination of their true 

 character or extent. The fresh water lakes and lagoons belong to the "New River" formation, 

 which has been sufficiently noticed above. 



II.— GEOLOGY AND MINERAL PRODUCTIONS. 



Directing the attention more especially to the geological structure of this region, we have to 

 consider the same mountain range, in its line of greatest elevation, constituting a central axis 

 from which we may trace on each side the diversities that characterize its extended flanks. 



By reference to the accompanying geological map and sections, three main facts will particu- 



