58 GEOLOGICAL SURVEY OF THE TERRITORIES. 



remnant of the great mass that once extended over the conutry from 

 the plains across the South Park, the Park range, Sawatch, &c., inter- 

 rupted, perhaps, here and there. We have already observed that the 

 Carboniferous as well as Silurian beds are omitted for one hundred 

 and fifty miles along the east margin of the mountains north of Colorado 

 Springs, while far north and far south the same rocks are well developed 

 in similar localities. So we may make the general statement that these 

 beds covered all this great area prior to the elevation of the ranges. 



As we proceed westward from Taylor's Eiver, we enter a region in 

 which the rocks have been thrown into a greater state of chaos than I 

 have ever observed anywhere in the West. There is no doubt that the 

 original inclination was toward the west from the Sawatch range, but 

 the great number of dikes that intersect the crust in many places, have 

 tipped the stratified rocks in every direction, elevated them to the sum- 

 mits of the peaks, and, in many instances, completely reversed their 

 position, so that we have the oldest rocks overlying those of more mod- 

 ern date. It is not uncommon to see ridges of quartzite, or limestone, 

 standing vertical, and, in some instances, inclining several degrees past 

 a vertical. To solve all these problems well would require that every 

 portion of the country should be studied foot by foot, and hundreds of 

 detailed sections prepared. Our plans would not admit of this detail, 

 and, therefore, much must remain obscure until we can gain the time 

 to make special studies of the more difBcult localities. Besides, we 

 need better maps, which are now in an advanced state of preparation. 



It is plain, however, that the sedimentary beds are essentially the 

 same as those of the Park range, and that they have been subjected 

 to greater overturnings than those of that range. There is at the 

 base, and resting on the granites, a great thickness, perhaps in the 

 aggregate 2,000 feet, of quartzites and limestone in alternate strata. 

 Above these is a great thickness of limestones of a more modern aspect, 

 with Avell-known Carboniferous fossils in them, and in some localities 

 very abundant and well preserved. Above these comes a vast group 

 of red sandstones assuming a great variety of textures, as well as 

 shades of color, at different points. Above come in regular order the 

 Jurassic and Cretaceous groups. In this district of chaotic overturnings 

 we saw no rocks of more modern age than the Cretaceous, though it is 

 quite probable that a more extended exploration would have discovered 

 them. The main streams that flow toward the west have cut deep 

 gorges directly through the uplifted ridges, as well as dikes, while the 

 side branches have formed in many instances parallel valleys. In all 

 cases the amount of detrital matter is very great. Huge masses of 

 granite are strewn over the surface, sometimes in the valleys and some- 

 times on the sides of the hills or mountains. The j)eak named on the 

 map as Italian Peak, 13,255 feet in height, is an example of the varie- 

 gated colors of the rocks, due to the flowing upward through the fissures 

 of the melted rocks, accompanied with a force that tilted the sedimen- 

 tary strata in all directions. 



Leaving the valley of the Gunnison, we took a southwest course, up 

 a fiearly dry, rather broad, grassy valley, to the divide, and descended 

 again to West Taylor Creek. These little side-valleys occasionally 

 close up for a short distance in a sort of gulch or caiion, then suddenly 

 expand out into an open oval one, covered with thick grass like a 

 meadow. This is a very common form in these mountain-districts, es- 

 pecially where the granites prevail. Soon after passing the divide we 

 find the sedimentary rocks cropping out everywhere. In the valleys 

 there is a great amount of the superficial drift, forming rounded hills or 



