331Gb Montana Shale Plains

Landscape Characteristics:

Dissected plains, hills, terraces, fans, and floodplains that formed in shale, siltstone, and sandstone. Elevations range from 1500 to 3500 feet. Drainage density is moderate to high.

Climate:

Mean annual precipitation ranges from 10 to 14 inches, about 30 percent falling as snow. The soil temperature and moisture regimes are frigid and aridic ustic. Summers are dry.

Potential Vegetation:

Grama-needlegrass-wheatgrass

Relationships of Dominant Map Unit Components:

Landform Geology Soil Taxa
Plains/hills Sedimentary Torriorthents/Camborthids/Ustochrepts/Argiborolls
Terraces/fans/floodplains Alluvium Camborthids/Natrargids/Argiborolls/Torrifluvents

Disturbance and Land Use:

The primary natural disturbance is drought and erosion. Land use is predominantly livestock grazing with some dryland farming.