The bedrock consist of Mesozoic granitic intrusives overlain by metamorphosed roof pendants. The Tioga moraine is superimposed on the Tahoe moraine. Distinctions between the two are easily made by the degree of erosion on the Tahoe lateral moraine crest and the degree of weathering, indicated by color changes, from a darker gray of the Tioga to a lighter shade of yellow in the Tahoe moraine. The alluvial fan deposits consist of unconsolidated, sand to gravel-sized clasts. The fans branch out laterally from incised channels within the bedrock, and extend across the lower regions of the field area.
Talus deposits form talus cones that form along the steep canyon walls.
The talus cones are generally located in close proximity to the faults. Colluvium deposits generated by small slides, earth flows, and debris flows accumulate along the base of the steep slopes. These deposits consist of thick, unconsolidated masses of bedrock and till. The northern extent of the fault extends from the NW corner of the field area to the McGee Creek road. The next reach of fault extends from the I395 and McGee Creek junction up to the base of the Tioga lateral moraine.