[1][2] The Wilcox Formation consists primarily of dark-gray to brownish-gray, muscovite rich, chlorite-quartz schist.

The schist is locally interbedded with either beds of chlorite-spotted, vitreous quartzite too small to map or prominent beds of vitreous quartzite as much as 10 meters (33 ft) thick.

This formation has a distinctive shredded, schistose appearance because of closely-spaced foliation and rusty-weathering cleavage.

Elsewhere within the Wilcox Formation, thin beds of white graphite-dolomite marble, and retrograded deep-orange-to tan-weathering dolomite are common.

At the type locality on Wilcox Hill and on the slopes south of Cold River, the schist contains pods of aplitic gneiss and veins rich in tourmaline.