at the base to about 9,400 feet (2,860 meters) on the highest peak. The eastern slopes drain into 

 the Ruby River Valley which separates the Ruby from the Gravelly and Tobacco Root 

 Mountains to the east. The western slopes drain into the Beaverhead River, whose broad valley 

 separates the Ruby from the Pioneer Mountains to the west. The Blacktail Deer Creek Valley, 

 which drains to the Beaverhead River, separates the Ruby Range from the Blacktail Mountains to 

 the south. 



The northern part of the Ruby Range is composed of tightly folded Paleozoic limestone 

 fomiations which create a steep topography of ridges and canyons. The lower flanks are met by 

 coalesced alluvial fans which descend into the surrounding broad basins. The southern part of the 

 Ruby Range is composed of Precambrian basement rocks (Alt and Hyndman 1986), mostly 

 gneiss and schists, which have weathered to a rolling, hilly topography. The metamorphic 

 basement rocks in the south include significant deposits of talc. 



The climate of the study area is continental and semi-arid. Meteorological data from Alder 

 (USDA Soil Conservation Service 1989) approximate the climate of the lowest elevations of the 

 study area. Average daily temperatures range from 21.7° F in January to 63.1 ° F in July. 

 Temperature extremes range from -32° to 93° F. Average annual precipitation is 12.89 inches, 

 with peak precipitation in May tlirough September. Climate at the higher elevations is cooler and 

 wetter; based on soil types, average precipitation at the higher elevations of the range is probably 

 about 24 inches (USDA Soil Conservation Service 1989). The east flank of the range is dryer 

 than the west flank and the entire range lies in a rain shadow of higher ranges to the west, making 

 it one of the driest ranges in southwestern Montana. 



General soil mapping units in the study area include the \Vliitore-Hanson-Rock outcrop with 

 primarily limestone parent materials in the northern part and the Oro Fino-Hapgood with 

 primarily gneiss and schist parent materials in the southern part (USDA Soil Conservation 

 Service 1989). The soils at the lowest elevations are aridisols, soils of the northern and western 

 mountain slopes are mostly inceptisols and some alfisols, and soils of the southeastern hills are 

 mostly mollisols. 



Vegetation 



The vegetation of the Ruby Range is mostly dry forest and woodland types, sagebrush shrubland, 

 and grasslands. Timbered habitats are most extensive. Most of the land in the north and on the 

 western flank in the south of the Ruby Range supports forests and woodlands. On the eastern 

 flank in the south, forests and woodlands are mostly confined to northern aspects. The lowest 

 elevations of the range support open Rocky Mountain juniper (Jimiperns scopulorum) woodlands 

 which grade into sagebrush steppe. Dry, rocky, south facing slopes support mountain mahogany 

 {Cercocarpus ledifoUus) woodlands or scrub and open stands of Douglas fir {Pseudotsuga 

 menziesii) and limber pine {Pinusflexilis). Denser stands dominated by Douglas fir are the most 

 extensive forests of the range, and occupy lower to upper cool, mostly north facing slopes. 

 Spruce (Picea) communities are confined to moist positions as narrow stringers in canyon 

 bottoms and on high elevation upper slopes; the taxon is generally treated as a hybrid swann 

 between P. engelmanii and P. glauca. Serai stands dominated by lodgepole pine {Pinus contortd) 



