A southeastward-plunging synclinal mountain ridge, capped by Mississippian rocks, rises from a base of Cambrian rocks in the Sunwapta Pass area.

Detailed sections involving Silurian and Devonian rocks were studied from the Nigel Peak area on the north southward to the Sunset Pass area.

The Mt. Wilson quartzite, heretofore referred to the Devonian, is shown to be Ordovician or Silurian in age and a probable correlative of the Wonah formation of British Columbia.

Halysites-bearing beds of probable early Silurian age rest unconformably on the Mt. Wilson quartzite and may correlate with the Brisco formation of British Columbia.

The Devonian consists of three formations, the coral-bearing Fairholme at the base, followed by the scarp-forming Palliser limestone, and capped by the Exshaw shale and limestone. Tentative correlations are made between the Leduc section and the Sunwapta Pass area for Devonian rocks.

Mississippian Banff shale rests unconformably on the Exshaw formation.