parallel with these havS a general course from northwest to southeast. 

 It extends through seventeen degrees of latitude, reaching from the 

 British Possessions to the ^Mexican boundary. Springing from elevated 

 plains and plateaus, which range in altitude from 3,000 to 7,000 feet, 

 the mountains of this system attain their greatest elevation in Colo- 

 rado, reaching there an extreme height of 14,460 feet above the sea. 

 The several parts of the system may be described briefly as follows: 

 Commencing at the boundary line between British America and 

 Montana, in the western part of the last-named Territory, the Main 

 Eange there takes a southeasterly course for a distance of about 200 

 miles; then it turns sharply to the west and at the boundary of Idaho 

 is joined by the Bitter Eoot chain of mountains, which run in a south- 

 easterly direction and form the middle portion of the dividing line 

 between Montana and Idaho. The Coeur d'Aleue Mountains, in north- 

 ern Idaho, constitute the northwest extension of the Bitter Eoot Mouu- 

 i ains. 



The Main Eange, from the point where it is joined by the last-named 

 mountains, continues in a southeasterly^ course on the line between the 

 two Territories and enters northwestern Wyoming near the south west- 

 ern corner of the Yellowstone IvTational Park. Continuing in the same 

 direction, the Wind Eiver Mountains form an important link in the 

 great chain. At their southeastern extremity they meet the Sweet- 

 water Mountains, a comparatively short range, trending eastward. The 

 crest, or dividing line, there turns to the southeast and passes over an 

 open country or high table-laud for a distance of 75 to 100 miles; it 

 then strikes the Sierra Madre Mountains, the northern extension of the 

 Park Eange of Colorado, which form a portion of the Maiu Eange. In 

 I^orth and Central Wyoming, the Big Horn, the Laramie and Medicine 

 Bow Mountains are the most notable adjacent ranges. 



The Colorado system commences on the north with the Park Eange, 

 which forms the western boundary of j!^orth Park. At the southwestern 

 angle of the park the main divide turns directly eastward, separating 

 [N'orthaud Middle Parks, and is joined by the Medicine Bow Eange at the 

 northeast corner of the last-named park. The Main Eange then bears 

 to the southeast for a short distance, then turns southwestward and 

 continues in that direction until it crosses the Park Eange a few miles 

 north of Leadville. The northern extremity of the Saguache Eange is 

 here reached. This range takes a course a little east of south, and ter- 

 minates about 40 miles southeast of the town of Gunnison, in south- 

 w^estern Colorado. A range called in part the Cochetopa Hills," and 

 running in a southwesterly direction, connects the Saguache with the 

 San Juan Mountains. The latter, bearing southeastward, terminate 

 near the southern line of the State. 



The principal secondary range in Colorado is the Park Eange, which 

 constitutes the western boundaries of iS orth, Middle, and South Parks, 

 and is crossed, as before stated, by the Continental Di\'ide. Other im- 



