OCR Text |
Show 154 EXPLORA'fiON Oli' THB OANONS OF THE COLORADO. folding began we have reason to believe that the general surface of this country was but slightly above that general standard of comparison. Then there were down-turned as well as up-turned wrinkles, or, as the geologist would say, there were synclinal as well as anticlinal folds. Had there been no degradation of the fold, there would have been a bed of rock turned over its summit twenty-four thousand feet above the present level of the river. Now that bed is gone from the mountains, yet it can be seen turned up on edge against the flanks of the mountains, dipping under the beds of rocks found still farther out from the range. Follow it down, and doubtless we could trace it to a depth much below the level of the sea. While the folds were forming, the upturned flexures were cut down, and the troughs in the down-turned flexures were filled up, and we have more than eight thousand feet of these later sediments to the north of the Uinta Mountains. It will thus be seen that the upheaval was not marked by a great convulsion, for the lifting of the rocks was so slow that the rains removed the sandstones almost as fast as they came up. The mountains were not thrust up as peaks, but a great block was slowly lifted, and from this the mountains were carved by the clouds-patient artists, who t8,ke what time may be necessary for their work. We speak of mountains forming clouds about their tops; the clouds have formed the mountains. Lift a district of granite, or marble, into their region, and they gather about it, and hurl their storms against it, beating the rocks into sands, and then they carry them out into the sea, carving" out canons, gulches, and valleys, and leaving plateaus and mountains embossed on the smface. Instead of having a rounded billow, we have an irregular table, with beds dipping to tho north, on the north side of the axis, and to the south, on the south side, and in passing over the truncated fold we pass over their upturned edges. Go out on the flank of the fold, and find the bed of rock which would form the summit of the great wrinkle, had there been no erosion, and there sink a shaft ~4,000 feet, and you will be able to study a certain succession of bec..ls of sandstones, shales, and limestones. Go two or three miles farther &·om the mountains, and sink a shaft; the first eight thousand feet or more |