TOPOGRAPHY 33 



forests. The ranges here enumerated thus constitute forest 

 islands in the plains country. 



Some peaks of this region rise to 9000 feet or more above 

 sea level. In the Little Belts, the central group of the area, 

 the average elevation is above 7000 feet. They) are mainly 

 limestone uplifts, seamed by numerous dikes of eruptive rock 

 with extensive areas of metamorphics. The ridge crests are in 

 some places narrow, in others flattened out into plateaus, as at 

 the head of the Lost Fork of the Judith and even marshy in 

 others, as where the divide descends into what was originally 

 part of the South Fork of the Judith Basin. Some of the 

 secondary ranges are largely of ignecus rock. Ridges radiate 

 on the eastern slopes of the main axis into long spurs of narrow 

 and winding form which separate the streams flowing to the 

 Judith River. They are seldom high but are usually of low 

 and rounded contour. On the west the spurs arc short and 

 steep and on the north they form a labyrinth of tortuous can- 

 yons. Many of the canyons throughout the area are narrow and 

 flanked by steep slopes or by limestone cliffs buttressed by talus 

 accumulations. Above they widen out into amphitheater-like 

 basins. To the north of this range a short distance stands a 

 small detached group, the Little Rockies which have an altitude 

 of 6500 feet or less, and support a forest growth. 



To the east of the Belts the neighboring elevations of the 

 Snowy Range are separated from the former by Judith Gap, a 

 rolling and fertile prairie country. These summits have eleva- 

 tions of 4000 to 8000 feet and are themselves divided into two 

 groups, the Big and the Little Snowys. The latter is the more 

 easterly and represents the most distant outpost of the Rocky 

 Mountains with forest vegetation between the Missouri and the 

 Yellowstone. 



The most southern members of this second general group 

 are the Crazy Mountains. They cover an area of some 360 

 square miles and reach an altitude of 10,000 feet. Geologically 

 and topographically they resemble the Absarokas of the southern 

 group, from Avhich they are separated by the broad valley and 

 rolling grassy benches of the Yellowstone. They rise abruptly 

 from the plains and their rugged sides and sharp ridges ascend 

 to clear cut peaks often cloud-crested and mantled with snow. 



