OF NORTH AMERICA. 
79 
The insufficiency of my observations upon the vast regions of the Rocky Mountains and the Sierra 
Madre , obliges me to confine myself to these summary indications of a portion of the dislocations which 
are found there. Being the first pioneer of Geology in these desert countries, I have fixed only a 
single landmark. 
11. Coast Hangs system. — All along the Pacific coast from Cape S' Lucas, in Lower California, 
to Cape Mendocino, Humboldt County, in Upper California, wo observe chains of mountains of small 
elevations, being in general 500 to 1200 feet above the level of the sea, known under the name of the 
Coast Range of California. The direction of this system of mountains is not far from N. N. W. and S. S. E. 
The part of the coast where this system is the most distinct and easy for observation , is from the 
Pueblo de los Angeles to the Bay of Humboldt, and between the sea and the rios San Joachin and 
Sacramento. In the small number of rapid observations I have been able to make , around Los Angeles, 
Santa Barbara, Monterey, Santa Clara, San Francisco, and Contra-Costa, it appeared to me that the 
dislocations and ruptures have taken place at the end of the Eocene Tertiary epoch, as seems to be 
indicated by the beds of limestone and sand containing fossils characteristic of the Eocene, which are 
found especially south of Monterey and at Monte Diablo in the County of Contra-Costa. 
The celebrated Golden Gates, of the Bay of San Francisco, traverse this system. The rocks com- 
posing it are chiefly of metamorphic and eruptive origin , and they contain rich mines of quicksilver, 
silver, copper, and iron; but thus far no gold has been found there. 
Most of the chains of the Coast Range are crossed and penetrated by subsequent dislocations, which 
have given birth to the System of the Sierra Nevada. These crossings are seen particularly near the mis- 
sion of San Fernando and the Tajon Pass, and also near the sources of the Russian river in the County 
of Mendocino. 
According to a manuscript chart and verbal communications made to me in 1854, by the cele- 
brated and unfortunate de Raousset Boulbon , I refer to this system of the Coast Range , the mountains of 
Sonora, comprised in the country of the Papayos Indians, and the Sierra of Arizona. There, as in Ca- 
lifornia , we do not find gold, but many very rich mines of silver, copper, lead, and quicksilver. 
12. Sierra Nevada system. — We comprise in this system not only the chain of the Sierra Nevada, 
known among geographers as forming the eastern limit of California , but likewise a group of eight or 
ten other parallel chains, extending to the east, even to the further side of the Rio Colorado. In a 
word, the group of mountains forming this system comprises all the Great American desert, from near the 
Salt Lake and settlements of the Mormons, to the plains of the Sacramento and San Bernardino , running 
north and south for ten degrees of latitude. 
The lines of dislocation run North and South, giving thus a second meridian system in North America. 
As the rocks which compose all these chains are principally crystalline, eruptive, and metamorphic, 
and as they contain veins of auriferous quartz, directed likewise from north to south, and of 
the same epoch as the appearance of the other rocks of this system — wo see that there seems to exist 
a relation between the deposit of gold and the Meridian direction of the chains of mountains , especially 
if we recall to mind that the three systems of mountains where gold is most common, are the Meridian 
systems of the Ural, the Sierra Nevada, and the Australian Cordilleras. 
The sedimentary rocks are very rare in the mountains of this group. They are mostly pudding- 
stone , white and red sandstone badly stratified , and white limestone. Fossils being very rare in this 
elevated and often highly inclined strata, it is difficult to assign a precise epoch for the relative age of 
the Sierra Nevada. That which is certain in my mind , is that this system is later than the Eocene pe- 
riod, and yet earlier than the Quaternary epoeh. It may be at the end of the Miocene, or after the 
Pliocene. In this respect I agree with Sir Roderick 1. Murchison , who considers , in his late and ex- 
cellent work, entitled Siluria, the deposits of auriferous sand of the Ural and of Australia, as effected 
at the epoch of the Quaternion drift, which gives as the geological age of the veins of auriferous quartz, 
the end of the Tertiary epoch , or the end of the Miocene period. 
