Quaternary geology and bedrock subcrop of the Cold Lake to Ft. McMurray area, Alberta - Surface structure, Empress Fm. Unit 1 sand and gravel - (1:250,000 scale gridded data) - Quaternary geology and bedrock subcrop of the Cold Lake to Ft. McMurray area, Alberta - Surface structure, Empress Fm. Unit 1 sand and gravel - (1:250,000 scale gridded data) - (ASCII GRID)