Recent major oil discoveries found in Upper Devonian reefs in central Alberta have greatly increased Devonian stratigraphic information. Knowledge of Devonian rocks is derived solely from subsurface information with the exception of two areas--the easternmost ranges of the Rocky Mountains in southwestern Alberta where Devonian and Mississippian rocks form the backbone of the mountains, and a part of northeastern Alberta adjacent to the Canadian Shield where Devonian rocks are exposed in low, discontinuous outcrops along the principal rivers.

Discussion is limited to Upper Devonian rocks occurring between the Elk Point formation (Middle Devonian?) below and Mississippian beds above. Regional aspects of Upper Devonian formations recognized are discussed individually by thickness and lithofacies maps and by stratigraphic sections. Regional structural maps drawn on the base of the Devonian D3 reef section, the top of the Devonian D2 formation and on the top of the Devonian, together with a pre-Cretaceous paleogeologic map are discussed.

Stratigraphy is the controlling factor of oil accumulation in Upper Devonian rocks of the Alberta plains area, with structural accumulation virtually absent. Interpretation of subsurface data is becoming increasingly more important.

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