172 GUIDEBOOK OF THE WESTERN UNITED STATES. 



the point of greatest height the walls decrease gradually and finally 

 disappear near the mouth of Elk Creek, a small stream that joins 

 Gunnison Kiver from the north. The granite, however, does not 

 completely disappear but extends down to milepost 306, or 1 mile 

 above Cebolla (say-bo'yah), where it passes below water level. 



Cebolla, which is one of the most noted resorts on the river for 



fishermen, is in a wide part of the valley on the north side of the 



river, at a mesa known as Tenderfoot Hill. The top 



Cebolla. of this mesa is 1,200 feet above the track at 



Elevation 7,354 feet. (jg^QUa The granite does not remain below river 



Denver 30 ( miles. *= _ _ . • £ /~\ 



level any great distance, for within a mile of Cebolla 

 it forms the walls of a narrow canyon, which, however, are not 

 more than 100 feet high. The smoothness and regularity of the 

 upper surface of the granite and the way in which it rises and 

 falls with reference to river level make it comparatively easy for 

 the traveler to understand how the Black Canyon has been cut. It 

 is evident that at the time the river established its course the granite 

 in neither of the small canyons so far described nor in Black Can- 

 yon was exposed, for the river was then flowing on the softer sedi- 

 mentary rocks that overlay the granite. As the river cut deeper 

 into its bed it uncovered the granite, but it could not shift its course 

 and thereby avoid the hard rock, so it had to keep at work laboriously 

 cutting its way into the granite. Although the granite canyons 

 about Cebolla are now shallow, they will become deeper and deeper 

 in course of time until the entire route from Gunnison to Cimarron 

 may be one granite canyon as deep and as impressive as the " Black 

 Canyon." It may be well to say that this great canyon will not be 

 seen by the coming generation nor the generation after the next, 

 nor even the one following that ; but the geologist knows that unless 

 conditions change such a canyon will be formed, although the time 

 may be thousands or millions of years hence. 



Below Cebolla the canyon is much the same as it is above that 

 place, except that the slopes above the granite become greater and 

 in places are composed of vast masses of volcanic breccia that 

 weather into fantastic forms. Where the granite is above the level 

 of the river the canyon is more or less rugged, but where it is below 

 the surface the valley is wide and the slopes are smooth and gentle. 



Near milepost 313 the granite passes below the level of the river 

 and remains concealed as far as the village of Sapinero (sah-pe- 

 nay'ro), which is a noted fishing resort and the 

 Sapinero. junction of the branch railroad that runs south- 



Eievation 7.255 feet, ward 36 mllcs to Lake City. From the station at 

 Sve'TiVmui. Sapinero the traveler, by looking back, may obtain 

 an excellent view of a great cliff of volcanic breccia 

 ^see PI. LXX, 4), and by looking forward he may see the granite 



