GANNETT.] 



DRAINAGE SYSTEMS. 671 



meridian of tbe land survey on the east, and by the one hundred and 

 seventh meridian on the west. The area is about 7,200 square miles. 

 This district is very much diversified, consisting of high plains, plateaus, 

 and mo-untain-ranges. 



The drainage systems may be classified as follows: — 



1st. That of the South Platte, which drains South Park and most of the 

 country east of it. The area embraced by this system is 3,300 square 

 miles, of which 1,700 square miles are plain or valley country, and the 

 remaining 1,600 square miles are mountainous. 



2d. That of the Arkansas River, consisting mainly of a broad, trough- 

 like valley, lying between the South Park and the main range of the 

 liocky Mountains, (which is there known as the Sawatch Range,) and a 

 considerable portion of the plains east of the mountains, and the mount- 

 ainous region about Pike's Peak, which are drained by a branch of the 

 Arkansas, known as the Fontaine qui Bouille. The area drained by 

 the Arkansas system is about 1,700 square miles, of which 500 square 

 miles are plain and valley country and 1,200 mountainous country. 



3d. That of the Gunnison and the Grand Rivers, which, heading in 

 the western slopes of the great Sawatch Range, flow in a general westerly 

 direction, draining all the country west of the Sawatch Range. 



The divide between these streams is a high range, known as the Elk 

 Mountains. The drainage area of the former is about 700 square miles, 

 of which 100 square miles are valley country and 600 mountainous. 

 The area drained by the latter is 1,500 square miles, 200 of it being val- 

 ley and 1,300 mountainous. 



Of the total area of the district, 2,500 square miles, or little more than 

 one-third, are plain and valley country, the remainder, 4,700 square 

 miles, being mountainous. 



The plains which form the eastern part of the district are drained 

 in part by the South Platte and its numerous branches, and in part by 

 the branches of the Fontaine qui Bouille, the divide between the two 

 systems, consisting merely of a slight rise in the level of the plains. 

 Tbe elevation of the plains at the north line of the district is about 5,300 

 feet, tbence the slope is gradual up to the divide, which has an eleva- 

 tion of about 8,000 feet, and thence the plains slope gently and regularly 

 down to the south line, where the elevation is about 5,000 feet. The 

 valleys of the streams are very slight, and in the dry season much of the 

 water sinks in the gravelly soil. There is no timber, except on the sum- 

 mit of the divide. 



The list of elevations along the Denver and Rio Grande Railroad, 

 which is appended, shows the i)rofile of the plains very well. 



Rising abruptly from the ]>lains on the west is a plateau-like range, 

 known as the Colorado or Front Range, which increases gradually in 

 elevation toward the south, until, near the south line, it culminates in 

 the group of mountains of which Pike's Peak is the center. Near the 

 north line the South Platte cuts through this range, and just north of 

 Pike's Peak the Fontaine qui Bouille heads in its western part, and 

 cuts a caiiou through nearly its whole width. Its elevation near the 

 north line is 8,000 feet, near the caiion of the Fontaine qui Bouille it 

 is about 9,000 feet. 



The mountains of the Pike's Peak group are from 10,000 to 14,000 feet 

 in elevation. The plateau is crested in many places by ragged granite 

 ridges, ©f which Platte Mountain or Devil's Head is the highest, 9,203 feet 

 above the sea. This range is sparsely timbered with pine and si)ruce. 

 West of this range the country consists alternately of beautiful, well- 

 watered parks and rugged granite slopes, as far west as the great 



