332 EEPORT UNITED STATES GEOLOGICAL SURVEY. 



Profile of the Rio Mancos. — (Haijden.) 



^ 



From 

 moutli. 



Elevation. 



Fall per 

 mile. 





Miles. 

 62 

 52 

 38 

 32 

 C'2 

 12 



Feet. 

 9,770 

 7,3G0 

 6,250 

 5,730 

 5,270 

 4, 9C0 

 4,7C0 



Feet. 



Merritt's ranch 



241 



7!) 

 87 

 46 

 37 

 17 









KoTE. — All elevations are barometric. 



Profile of the La Plata Biver. — (Haydcn.) 





From 

 mouih. 



Elevation. 



Fall per 

 mile. 



Parrott City 



Miles. 

 43 

 38 

 22 

 10 



Feet. 

 8, 500 

 7,92>' 

 6, 270 

 5,500 

 5,297 



Feet. 



Mouth 



116 



103 



64 



00 









Note. — All elevations are barometric. 



DRAINAGE AREA OF GRAND RIVER. 



The Grand River unites with the Green to make the great Rio Colo- 

 rado of the West. Its head is among the suow-fields of the western 

 slope of the Front Range, in the northeastern JDart of Middle Park. Its 

 drainage area in Colorado comprises 22,100 square miles. It consists of 

 the Middle Park and the inner slopes of its mountain barriers, a large 

 part of the Park Range, the western slopes of the Sawatch Range, the 

 Elk Mountains, the north and west slope of the San Juan Mountains, 

 the southern portion of the great White River Plateau, besides an enor- 

 mous area of the broken plateau country farther westward. Its course 

 from its head to its junction with the Green is, in general terms, some- 

 what south of west, at right angles to all the ranges and ridges. Con- 

 sequently a large part of its course is in caiion, in forcing its way across 

 the uplifts which it encounters. The arable area on the main stream is 

 comparatively inconsiderable, being confined to cross-sections of the 

 valleys which it traverses. The total area of arable land on this river 

 and its branches is estimated at 1,200 square miles. Of this but 320 

 square miles are on the main river. This estimate covers all the level 

 laud which can be reached from the stream, and has no reference what- 

 ever to the volume of water carried by the stream, which is largely in 

 excess of that required to irrigate this area. The river was gauged 

 just above the mouth of the Gunnison on the 23d September, and found 

 to carry 4,850 cubic feet per second. At the close of July it must carry 

 at least 6,000 cubic feet. Other measurements, higher up the stream, 

 have been made. Just below the mouth of the Eagle, a large branch 

 from the Sawatch Mountains, it carried, in Ifovember, 871 cubic feet, 

 and at the Hot Springs in Middle Park, near its head, it carried, in 

 September, 802 feet. These last two measurements were made by Mr. 

 S. B. Laddj at that time attached to this survey. 



