Geologic age: Precambrian

Drive 0.2 miles north from Stop #5. There is an outcrop of schists along the left side of the road. Park at the small pullout on the right side immediately after driving under the bridge. Be careful of traffic on this curved road.

Like pegmatite, schist is part of the Precambrian core of the Black Hills. Schist is a metamorphic rock composed of shiny mica minerals. It is identified by distinct foliation, which is a geologic term meaning very fine layering. Distinct foliation indicates that great pressures occurred within the earth. Rock layers form at right angles to the source of pressure.

In what direction have the layers formed? What does this tell us about the direction from which the pressures came? Can you find any small folds in the schists?