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Show 171 elbow which unites them. Nevertheless the dislocations which broke the Tertiary strata, and raised them to form the Coast Range, the Mount Diablo range, the sierras of San Rafael, of San Fernando, & c, did not appreciably affect the Sierra Madre and still less the Sierra Nevada. Meeting with a powerful barrier, the Tertiary strata were pressed back against the obstacle of the Sierra Madre and were in some places folded back ( repliees) upon themselves, becoming contorted, and their beds being turned in an opposite direction, perpendicular to that of these granitic and crystalline mountain- chains. I have not seen any indications which prove that the Sierra Madre was ever subjected to the uplifts of the Tertiary epochs. Bat, then, at the close of the Quaternary epoch, and perhaps even in the Modern epoch, there are proofs of uplifts and dislocations, which are particularly perceptible on the eastern side of the chains of the Sierra Madre throughout the whole length of the California Desert. The principal proofs of great movements on the sides ot the Sierra Madre toward the end of the Post Pliocene age, and during the Modern epoch, are: First, the eastern counterfort of the Sierra Madre at the Cajon Pass, at the very place where the pass attains its greatest elevation above the level of the sea, which, according to Gen. A. W. Whipple, is 4,559 feet; here there are very heavy strata of white sand with rolled pebbles, arranged in beds or scattered through, the sand ; these strata have been greatly uplifted by the Sierra Madre. Although the stratification of this kind of drift is quite indistinct and confused, it is clearly seen that the whole of this formation dips in an easterly direction at an angle which even attains 45°, which is a very great inclination for rocks which are almost friable, { mtubles.) The Sierra Madre evidently forms the anticlinal or uplifting mass. The thickness of this formation may be estimated at 1,500 or 2,000 feet. What is its age f It is scarcely possible to tell, because no fossils have as yet been found in it. Nevertheless many of the rolled pebbles contained in this sandy mass are fragments of trachytes and basalts, which shows that this formation is very recent, certainly much more recent than the Pliocene in the vicinity of Los Angeles, and that it can only be referred to the Post Pliocene or Quaternary formation. On the other hand, the great California Desert, between the Sierra Madre, the Sierra Nevada, Death Valley, and the valley of the Mohave River, indicates the existence of an ancient lake, now dry, the banks and old beaches of which are still seen in many places, notwithstanding the continual movement of the sand, which is violently driven by the west wind. As extinct volcanoes are met with all along the Colorado River, in the basins of the Mohave and the Araargosa, and as very violent earthquakes still take place throughout a great portion of this region, it is natural to suppose that the last uplift and elevation of the Sierra Madre, and of a portion of the Sierra Nevada, took place at the close of the Quaternary period, or even in modern times. This is the conclusion which I reached in 1854, and which I stated in my " Sketch of a geological classification of the mountains of a part of North America," ( see Geology of North America, Sierra Nevada system, page 79; Zurich, 4to, 1858,) only I expressed no opinion with regard to the dislocations which had previously taken place in this system of the Great American Desert, which I called a second meridian system in North America. The discoveries made since, principally by miners, in the Sierra Nevada and the ranges of the Great Basin, of the primordial or Taconic fauna, and of the Carboniferous, Triassic, and Jurassic faunas, show that from the earliest times of the Upper Taconic, tbere have been terra finna in that region which had emerged from the sea; that the granitic arites of the ranges which cross this entire country date from the beginning of the Paleozoic ages ; that the Carboniferous, the Trias, and the Jura penetrate only into narrow valleys of this system; and that during the Tertiary ages there was an enormous mass of terra Jirma here, which, like the Alps, furnished the arenaceous and pebbly materials for the deposits of the marine and of frc* h- water Tertiary rocks, which are now found in California, Utah, Wyoming, and Colorado. " En resume*," the Sierra Madre is altogether the most ancient aud the most modern mountain chain of this region of Southern California; that is to say, that the granite, pegmatite, gneiss, dioritic, and mot amorphic rocks which form its principal mass date from times anterior to the Paleozoic epochs, ou tout au plus paldozoiquts m€ mes; and that the counterforts of sand, sandstone, and conglomerate, which form the snmmit of Cajon Pass and of other portions of the eastern region of this chain, date from the Post Pliocene or Quaternary epoch. COAST RANGE.- The name of Coast Range signifies a chain of mountains which follows the line of the coast of the Pacific Ocean. By way of extension, all mountains which are near the coast have been comprised in California under this elastic designation, no regard being had to the direction in which the chains run, whether parallel to the coast or perpendicular to it. After leaving Point Conception and Santa Barbara, and even the Sierra de San Rafael, we find that the mountaiu chains, instead of running from north- northwest to south- southeast, run from west to east, being perpendicular both to the Sierra Madre and to the sea- coast; so that, properly speaking, the Coast Range, which is so well defined at Monterey and San Francisco, terminates in the southern part of San Luis Obispo County, as was correctly observed by Dr. Trask in |