52 
the ‘Three Tetons,” prominent 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 tne 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 Range is very irregular; other high ridges abut upon or cross if, - 
and detached groups appear upon eitherhand. 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 almest 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 slopes 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 “ cround plan” of this mountain system is so irregular and of 
such great extent that, in the absence of surveys, it is impossible 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. 
Aithough 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 exposure. 
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 6,000 feet above the sea, the greatest elevations 
being in Wyoming, Colorado, and northern New Mexico; thence slop- 
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. 

