230 GEOLOGICAL SUEVEY OF THE TERRITORIES. 



Situated between 37° and 41° of nortli latitude, and 102^ and 109° of 

 west longitude, Colorado Territory extends east and west about three 

 linndred and ninety miles, and north and south about two hundred and 

 seventy-live miles, forming a rectangle containing an area of 100,500 

 square miles, or 68,144,000 acres. Eeaching from near the middle of 

 the great trans-Mississippi plain up the mountain sloi)e, it laps over the 

 summit of the great divide and rests its western border on the Colorado 

 basin. And including, as it does, within its bounds the great system of 

 mountain parks, and the sources of the four great rivers, the Eio Grande 

 del ]S'orte, the Eio Colorado, the Ai'kansas, and South Platte, it has 

 been appropriately termed " The Gem of the Mountains." And, like 

 Switzerland in Europe, it may be said to be unique in its geographical 

 features. 



Of the large area contained within its boundary lines, about four- 

 sevenths are embraced in the true mountain region, whose snowy sum- 

 mits form the watershed of the continent. The remaining three-sevenths, 

 situated, chiefly, east of 105° of west longitude, and extending the whole 

 length of the Territory north and south, consist, in great part, of broad 

 plains furrowed by shallow valleys, widening and fading away as they 

 extend eastward 5 and, with the exception of the parks and some valleys 

 of the mountains, contain all the arable lands of the Territory. 



But since much of this latter portion, lying along the eastern bound- 

 ary, is devoid of water, excex)tiug the few streams which traverse it, 

 the agricultural population has, as yet, been confined within a comj)ara- 

 tively narrow strip along the eastern slope of the mountains. 



In order to obtain a more correct and minute idea of the geographical 

 position and extent of that portion of the Territory which is susceptible 

 of cultivation, it will be necessary to consider it in separate districts. 

 And we are not left, in this, to mark out arbitrary lines, for nature has 

 fixed prominent lines and permanent boundaries to each. Water is the 

 great desideratum in the agricultural development of this country, and 

 the method of its distribution we shall find is the true key to tlie agri- 

 cultural system of the Territory, and its turning sheds the boundaries of 

 the districts. 



Beginning at the northern part, we find the South Platte Eiver is the 

 outlet for all the water of this section which flows towards the Atlantic. 

 Moving up this stream from its point of exit, near the northeast corner 

 of the Territory, it will be seen that after crossing the 104° of west 

 longitude it branches rapidly into its numerous tributaries. The portion 

 of country drained by these numerous minor streams is bounded on the 

 west by the eastern slope of the Eocky Mountains, and on the south by 

 a high, broken, irregular ridge called the Divide, which, starting from 

 the base of the mountains opposite South Park, runs eastward until lost 

 in the plains. This constitutes the northern agricultural division, which, 

 for convenience, I shall name the Denver district. 



This Divide separates the waters of South Platte from those of the 

 Arkansas, and forms the northern boundary of the second district, which 

 is the area- lying between it and the Eaton Mountains. This division, 

 which may be appropriately named the Arkansas district, is drained by 

 the Arkansas and its tributaries. These two districts contaiumost of 

 the tillable land of the Territory lying east of the mountains. 



I may as well remark here, that in my use of the terms " tillable," 

 " arable," " susceptible of cultivation," &c., I do not intend thereby to 

 exclude the idea of the future possibility' of cultivating other sections, 

 but simply intend to express the fact, that those sections, so termed, are 

 now sufficiently sui)i)lied with water for farming pui'poses. ' 



