The Red Dirt occurrence is at least partly controlled by the Red Dirt fault, which strikes NE and is nearly vertical. Rocks on the southeast side of the fault are calcareous mica schists of the Birch Creek Schist. Rocks on the northwest side are complexly folded and faulted graphitic and quartzitic schists, also of the Birch Creek Schist (Thornsberry, McKee, and Salisbury, 1984, v. 1, fig. K-30). Several large ferricrete 'kill' zones roughly parallel the Red Dirt fault. (Vegetation is sparse to absent in the kill zones).

The graphitic schist, which is infolded with garnet-quartz-mica schist and quartzite, is a possible host of stratabound mineralization. It contains as much as 3 percent pyrite and pyrrhotite(?), and sample assays show small amounts of copper, lead, zinc, and silver. A reddish soil zone about 800 feet long parallels the Red Dirt fault; it contains as much as 0.43 ppm gold and 120 ppm arsenic.

Zinc appears to have been mobilized by acidic surface waters. Stream- sediment samples collected immediately below the ferricrete zones contain less than 75 ppm zinc; samples collected about a mile downstream contain as much as 400 ppm zinc. The pH of waters below the ferricrete zones is about 3.5; downstream waters are less acidic.