The lower Paleozoic section in western White Boy is divided into two groups. The Coney Arm Group is probably of Cambrian-Ordovician age; it is characterized by two cleavages and biotite-grade regional metamorphism. No fossils are known from this group. The Sops Arm Group shows one cleavage and chlorite-grade metamorphism. The highest formations--the Simms Ridge and the overlying Natlins Cove Formations--contain Silurian corals and brachiopods. Regnell has examined cystids from the top of the latter formation which he considers to have affinities with those in the topmost Silurian Clam Bank Formation of the Port au Port area, western Newfoundland.

Three new formations are established within the Sops Arm Group. The group consists of shallow-water sandstone and conglomerate, together with basic and acidic volcanic and pyroclastic rocks, including ignimbrite. The conglomerate and coarse arkosic units thicken north-northeastward, and cross-bedding and primary current lineations indicate transport from that direction.

The Sops Arm Group is thought to have been deposited in a shallow-marine environment; periods of temporary emergence are indicated by the presence of the ignimbrite. A land area probably lay on the north.

Although the environment of deposition was one of shelf seas, the structural setting suggests that the western margin of the mobile belt should be considered to lie west of these outcrops.