CHAPTER III. 



CULTIVABLE AEEAS OF COLOEADO. 

 THE NORTH PLATTE DRAINAGE AREA. 



The Platte, or Shallow Eiver, as the name was rendered in English 

 in the earlier days, drains the eastern slopes of the Eocky Mountains, 

 from the forty-third to the thirty-eighth parallel of north latitude. Its 

 branches head opposite to those of the Colorado and interlace with the 

 head of the Arkansas. 



In latitude 41°, longitude 101°, it divides into two branches, known as 

 the North and South Platte. The former drains the North Park, Laramie 

 Plains, the Laramie and Medicine Bow Eanges, and the northern part 

 of the Park Eange. Its course is very devious. Heading in the North 

 Park, it collects its waters from all sides of this mountain-locked basin. 

 Emerging from the ])a,rk on the north, it pursues a course nearly north 

 to its junction with the Sweetwater, in latitude 42° 20', where it turns 

 abruptly to the eastward, and after pursuing a course nearly east for a 

 long distance, past the northern extremity of the Laramie Eange, it 

 bears gradually southward and pursues a course generally somewhat 

 south of east to its junction with the South Platte. Its drainage area 

 within the limits of Colorado is but 2,000 square miles, and consists of 

 a part of North Park and the surrounding mountains. North Park is 

 one of those high mountain valleys which form so characteristic a fea- 

 ture in Colorado topography. It is in shape nearly elliptical, its longer 

 diameter lying nearly north and south and 35 miles in length. Its area 

 is 914 square miles. The surface is very level, and in certain parts 

 swampy. Its elevation, 7,500 to 7,700 feet above sea-level, together with, 

 the latitude, preclude the possibility of its being used to any extent as 

 an agricultural area, and the same causes make it risky to attempt to 

 Vinter stock there without hay and shelter. As a summer range it is 

 unexcelled, as its native product is mainly bunchgrass, which grows 

 luxuriantly. The arable area of the park is estimated at 232 square 

 miles, while the remainder of the area of the park, 682 square miles, is 

 available, as was stated above, as pasturage in summer. 



DRAINAGE AREA OF THE SOUTH PLATTE. 



The South Platte drains the South Park and the Front Eange from 

 latitude 39° to the northern boundary of the State. Its drainage area 

 within the State is 20,800 square miles, and this is nearly all of its entire 

 drainage area. The extreme head of this stream is directly under Mount 

 Lincoln, in the northwestern corner of South Park. Its general course 

 across the park is southeasterly, as are those of its principal branches 

 in the Park, High Creek, the Little Platte, Trout Creek, and Tarryall 

 Creek. All these enter the main stream within the Park, except the last, 

 which joins it in the calion, below its exit from the Park. The South 



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