Mt. Davis (Negro Mountain)
       7 ½’ quadrangle: Markleton, PA
       Somerset County
       Mt. Davis Natural Area, Forbes State Forest
       Allegheny Mountains

Sedimentary
3, 213 ft (979m)

View from fire tower at Davis Mt. (1995)

Bedrock: Pottsville Sandstone

Early Pennsylvanian

White to gray sandstone and conglomerate. The Pottsville is folded by broad open folds in the Allegheny Mountains. At Mt. Davis the rocks dip eastward under younger rocks in the Berlin syncline. On the east side of the syncline, the formation reappears dipping west on Allegheny Mountain. Farther east, on the other side of the next anticline, the Pottsville dips east again to form the ridge of Big Savage Mountain and Backbone Mountain, Maryland (see Maryland highpoint).

Surficial Geology: Unglaciated. However, tundra conditions during the Pleistocene produced stone rings caused by frost heaving. A good description of the process can be found at the Forbes State Forest website (see below).

Soil Series: Hazleton very bouldery sandy loam : dark grayish-brown, well drained, channery sandy loam over yellow-brown subsoil. Formed from weathering of underlying bedrock, with rocks covering more than 60% of the area. This is the "state soil" of Pennsylvania. See photos at: http://soils.usda.gov/gallery/state_soils/#list

Selected References:

• Flint, Norman K., 1965, Geology and mineral resources of southern Somerset County, Pennsylvania: Pennsylvania Geological Survey County Report C56A, 267p. (The geological map of Somerset County might be familiar to many former geology students due to its inclusion in the Williams & Heinz Map Corporation's lab collection of historical geology maps.)
• Yaworski, Michael S., 1983, Soil Survey of Somerset County, Pennsylvania : U.S. Soil Conservation Service.

Other suggested sources of information:

• Glossary: http://www2.nature.nps.gov/geology/usgsnps/misc/glossaryAtoC.html
• Time scale: http://www.ucmp.berkeley.edu/help/timeform.html
• Pennsylvania Geological Survey: http://www.dcnr.state.pa.us/topogeo/
• Mt. Davis Natural Area: http://www.dcnr.state.pa.us/forestry/stateforests/forbesnatural.aspx