52 



the " Three Tetous," promiuent snow-clad peaks, rise above the surround- 

 ing country. 



In Wyoming the principal range follows a tortuous line from the 

 northwest to the southeast. There is a break in its southern extremity', 

 and other ranges flank it at various angles upon the right and left, 

 separated from each other and from the Main Range by high plateaus, 

 sandy plains, grazing lands, and fertile valleys. 



In Colorado the system is complex in the extreme. The course of the 

 Main Eange is very irregular; other high ridges abut upon or cross it, 

 and detached groups appear upon either hand. ^Natural parks of great 

 magnitude, surrounded by high mountains and each containing the 

 head waters of an important river, here constitute a marked and agree- 

 able feature. The mountains, as well as the general level, are higher 

 here than elsewhere, and the ranges more massive. From almost any 

 of the snowy summits scores of others may be seen. 



The Culebra Range of northern New Mexico is a continuation of the 

 general system, and is similar in character to the Colorado Mountains. 

 Many of the mountains in Montana have smooth sloi^es and rounded 

 outlines. In other parts of the range they are generally rugged, 

 many having serrated crests and angular peaks. The sides are often 

 rocky and precipitous, and the summits, of naked rock, extend far above 

 the limits of vegetable life. 



The "ground i^lan" of this mountain system is so irregular and of 

 such great extent that, in the absence of surveys, it is imi^ossible to 

 determine its area with any degree of certainty. A conservative and 

 approximate estimate would give it a length of 1,500 miles and an aver- 

 age breadth of 200, or a total area of 300,000 square miles. 



Although the general course of the system is in one direction, the 

 ranges, spurs, and groups lie at many and varying angles, and present 

 the utmost diversity of form and exx)0sure. 



At the base of the mountains, on the east, are foot-hills and high 

 mesas,* and these merge into wide, rolling plains. On the west the 

 mountains are bounded by foot-hills, mesas, elevated plateaus, and 

 wastes of sand and lava. In many places appear water-courses, canyons, 

 and valleys. 



Plains. — Second only in importance to the mountains are the Great 

 Plains, which bound the mountains on the east for almost their entire 

 length and extend hundreds of miles to meet the prairies of the Central 

 Basin. 



The western border of this region, adjacent to the range, varies in 

 altitude from 3,000 to 0,000 feet above the sea, the greatest elevations 

 being in Wyoming, Colorado, and northern New Mexico ; thence sloj)- 

 ing to the north, east, and south, coincidently with the direction of the 

 principal water-courses. 



* Mesa (Sp.), the common name for the table lands (which are usually quite arid) 

 in central and western North America. 



