OCR Text |
Show 170 4 foot of the mountains between Tejon Pass and Caliente. There, just as one goes up from the great plain of Lake Tulare to the plateau which overlooks Caliente, oue sees enormous blocks of granite with an entirely northern exposure, piled the oue upon the other, with glacial drift mixed among them, which forms, without the slightest doubt, a beautiful frontal " moraine." The road which leads from Bakersfield up to Cerro Gordo, Panamint, and the California Desert passes close by these remains of " moraines." Although outside of my exploration, I cannot forego the pleasure of referring to the magnificent frontal " moraine" of the great glacier which must have come down from Pike's Peak, have covered the entire valley of the Manitou Springs, and have come to a stand- still midway between Manitou and Colorado City. The house or inn, called the " Half- way House," on the road is built on this frontal " moraine " itself, and the road crosses it at this place. Lateral " moraines," moreover, are seen on each side, especially in the direction t) f the Garden of the Gods. Mountain chains and their ages.- Our knowledge of the mountains of California to the south of San Francisco is so limited and such strange confusion has arisen that, notwithstanding the small number of my observations, and the meageruess of the results obtained, I do not hesitate to present them, in the hope that they may lead to a more rational and systematic study of this subject. In general, everything iu California that is not in the Sierra Nevada, properly so called, is thrown into the coast range. This coast range is naturally known by various local names. Great confusion has evidently arisen from the placing together of chaius of mountains running in totally different directions, of different relative ages and different geological constitutions. The Sierra Madre.- The Sierra Madre is but an uninterrupted continuation of the Sierra Nevada, which deviates abruptly from its general direction, that is fo say, from north to south, with slight tendencies toward the west and east, to form an elbow at Walker's Pass ; this elbow runs through the Tehachipi Pass, the Tejon Pass,, and stops at the Canada de las Uvas, in order to resume its principal direction from north to south. This double elbow may be compared to the point of junction of a bayonet on a gun. Geologists have long been familiar with breaks of this kind in the rocks of the earth's crust, and faults of this shape are often met with, which are very appropriately called " bayonet- shaped faults." What is the extent of the Sierra Madre, which, like the Sierra Nevada, is formed of several parallel ranges, ( chainons f) I cannot tell. I may say, however, of my own knowledge, that the Cajou Pass crosses it, and Mount San Bernardino forms a part of it. Iu 1854, in my exploration on the thirty- fifth parallel, in company with my lamented friend, the late Gen. A. W. Whipple, Engineer Corps, I was struck with the identity of the crystalline rocks of theCajon Pass with those which I saw in the vicinity of Nevada City and Grass Valley, in the Sierra Nevada, and I did not hesitate at that time to regard them as being of the same geological age, and as containing, in all probability, the same valuable minerals. ( See Pacific Railroad Explorations, vol. 3, 4to, Geological Reports, page 171, Washington, 185t>.) Since then, my explorations of the San Gabriel, Pacoiina, aud San Francisquito Canons have confirmed me in this opinion ; Winston's silver- mine, moreover, in the San Gabriel Cafion, reminds one in every respect of the silver- deposits of Virginia City and Washoe. After crossing an enormous granitic mass, on a width of at least 4 miles between the entrance of the San Gabriel Canon and the Winston miue, oue meets with serpeutiuous dioritic rocks, very hard, and which, near their poiuts of contact with the grauite, contain silver and copper iu abundance. Throughout the length of the Sierra Madro oue meets with more or less auriferous drift, identical in all its characteristics with that of the placers of the Sierra Nevada; the want of water alone has prevented its being washed to advantage. The Sierra Madre being only a bayonet- like prolongation of the Sierra Nevada, is of course of the same geological age. This age has hitherto been a problematical one, notwithstanding that it has been proclaimed with some ostentation to be of the Jurassic epoch. There is no doubt that the Sierra Nevada and all the ranges or sierras of Colonel Fremont's " great basin " are much more ancient than Jura. Like all complicated chains of mountains which extend over large surfaces, the Sierra Nevada was not made a* once, but at various times and at different geological dates. The Sierra Nevada and the Sierra Madre have been terra firma from the most ancient paleozoic times: and it is certain that the exisieuce of gold dates from those remote periods, like the gold of Australia, the Ural, Wales, Canada, the Carolinas, aud British Columbia. Elevations and ruptures of crystalline and stratified rocks took place in the Sierra Nevada, the Sierra Madre, and others of the great basin, toward the close of the Carboniferous, Triassic, Jurassic, and Cretaceous eras, and left very perceptible traces in certain places, especially near Mount Shasta, Bass's ranch, Plumas County ; El Dorado Canon, Humboldt ranges, Mariposa Couuty ; Inyo range, Cerro Gordo, and Panamint. The Tertiary sea washed the western sides of the Sierra Nevada and Sierra Madre, and in some places even penetrated these mountains especially at the bayonet- like |