The formation consists mostly of pyroclastic rocks that were laid down in a series of explosive eruptions about 100 million years ago during the Albian stage of the Early Cretaceous epoch.

[5][6] Blairmorite, a rare analcime-rich rock-type named for the town of Blairmore, Alberta, is known only from the Crowsnest Formation and a locality in Mozambique.

The eruptions probably occurred to the west near what is now Cranbrook, British Columbia, and the material was subsequently moved eastward by thrust faulting during the Laramide orogeny.

[2] The Crowsnest Volcanics are exposed along a series of folded, west-dipping fault plates in the Front Ranges and foothills of the southern Canadian Rockies.

They reach maximum thicknesses of 426 to 488 metres (1,400 to 1,600 ft) along a trend that extends northward from Coleman along McGillivray Ridge to Ma Butte.