Skip to Main Content
Book Chapter


January 01, 1954


The time interval represented by the sub-Devonian unconformity in the eastern Rocky Mountains varies considerably. The Devonian rests on Cambrian rocks in the south, but farther north, a thin sequence of unfossiliferous dolomites of uncertain age intervenes between the Cambrian and Devonian strata in the front ranges along and north of Bow River. Farther to the west, the Devonian overlies a sequence of Ordovician dolomites and quartzites of varying thickness and age. An early Ordovician (Canadian) fauna, characterized by Bellefontia and other trilobite genera, occurs widely, affording a useful horizon marker. A late Ordovician (Richmond) fauna occurs in the so- called Halysites beds and other Ordovician horizons may be represented. Little or no angular discordance is visible at the sub-Devonian contact and the magnitude of the break is evaluated from faunal and stratigraphic evidence. Study of the sub-Devonian unconformity may provide a clue to the loci of Devonian reef complexes.

You do not currently have access to this article.

Figures & Tables


AAPG Special Publication

Western Canada Sedimentary Basin: A Symposium; Sponsored by the Alberta Society of Petroleum Geologists, and the Saskatchewan Society of Petroleum Geologists

Leslie M. Clark
Leslie M. Clark
Search for other works by this author on:
American Association of Petroleum Geologists
ISBN electronic:
Publication date:
January 01, 1954




Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal