DENVER. & RIO GRANDE WESTERN ROUTE, 171 



down of the granite has made the surface of the land adjacent to 

 the tops of most of the narrow canj'ons flat — in other words, the 

 streams have cut trenches in mesas or plateaus. 



In the Gunnison Valley another chapter has been written as an 

 episode in the geologic history of the general region — a chapter re- 

 cording events of a time, after the sedimentary rocks had been de- 

 posited, when the region was covered with lava flows or with material 

 derived from them or from volcanic eruptions. 



From the summary of the geologic history of the region just given 

 the scenery below the town of Gunnison, even including that in the 

 Black Canyon, may be more readily interpreted. The country for a 

 few miles below the station at Gunnison must have been at some time 

 long past flooded with lava. The volcanic rocks thus formed are now 

 generally soft, but in places, as on the upland southwest of the station, 

 they rise above the general level in great monuments or spires, making 

 a very rough country. (See PI. LXX, B.) The character of the vol- 

 canic rock — a breccia — which composes much of the surface where the 

 slopes are smooth, may be seen in the cut at milepost 290. 



Wherever the granite appears above the level of the streams they 

 have cut into it narrow canyons, above which the slopes may be very 

 gentle up to some horizontal bed of sandstone, which generally stands 

 out as a mesa cap. "VVliere the slopes are gentle and the valley is broad 

 hay fields abound, but where the valley narrows down to a canyon the 

 bottom can not be cultivated. 



The first large canyon below Gunnison begins at a siding called 

 Hierro (yay'rro; Denver 294.5 miles), where the top of the granite 

 stands at track level. The top of the granite rises downstream, and 

 within a short distance below the siding the train passes through a 

 pretty little winding canyon, whose granite walls range in height 

 from 100 to 150 feet. The scenery in this canyon is not grand and 

 striking, like that in the Black Canyon, farther down, but many 

 beautiful views may be obtained of the clear, sparkling river, the 

 fringe of willows and cottonwoods, and the gray canyon walls. The 

 canyon ends at Elkhorn (Denver 297 miles), a resort devoted entirely 

 to the followers of Izaak Walton. Below this place the canyon widens 

 out, the granite decreases in height above the stream, and the slopes 

 above the granite include horizontal beds of sand- 

 ^^" stone, so that they are made up of a number of 



Elevation 7.450 feet, mesas or terraces. Hay ranches abound in the 



Population 111.* inn • ^^^ T 



Denver 29st miles. broad valley, and opposite the village of lola even 

 the terrace formed by the granite about 50 feet 

 above the bottom of the valley has been irrigated and yields flourish- 

 ing crops. 



A mile and a half below lola another granite canyon begins, and 

 in a short distance its walls rise to a height of about 150 feet. From 



