Physiography

The LoDaisKa Site is located beneath an outcrop of Fountain Sandstone, about a mile south of Morrison, on the ranch of Otto Sanger. Physiographically the Morrison area is part of the Southern Rocky Mountain Province. Broad elevated strips of granite, running north and south, are flanked by dipping sedimentary rocks. The latter are generally lower and form foothills. Both once formed continuous anticlinal structures, now deeply eroded (Fenneman, 1931). The granite masses are usually mountainous, but occasionally form vast plateaus such as South Park. Locally they are capped by remnant sedimentaries.

Courtesy U.S. Geological Survey

Figure 3—Morrison Biome, looking west. Central Ridge is the Hogback. Note encroachment of trees along watercourses and at higher elevations.

For over half the mountain frontage of this Province, a very resistant formation, the Dakota Sandstone, creates a “hogback”. A valley of weaker sedimentaries lies between it and the foothills, beginning about two miles to the west. The Fountain Sandstone, locally known as the “Red Rocks” formation, outcrops in this depression.

Mountain streams collecting in the inter-ridge valley form a trellis drainage pattern. Master streams cut through the Dakota Formation creating watergaps. The LoDaisKa Site lies in the shelter of an outcrop of the Fountain Sandstone which rises some 60 feet above the valley. The site lies at an elevation of about 6200 feet.

Climate

PrecipitationTemperature
Av. Ann.Max. Min. Mean Ann. Mean
Ann. Max. 		Mean
Ann. Min.
Morrison 14.20″22.96″7.51″[1]
Denver15.70±″23.10″7.84″50.3°63.2°37.3°
Av. Ann. Snowfall
55.6″