This GIS layer is a generalized compilation of existing geological maps and original geological mapping by Alberta Geological Survey staff (http://www.ags.gov.ab.ca/publications/abstracts/MAP_600.html). Mapping included field observations and creating three-dimensional models of subsurface stratigraphy based on the interpretation of geophysical logs from oil and gas wells. Each three-dimensional formation surface was projected to a model of the bedrock surface and the intersection formed the first approximation of the position of the geological contact at the base of the surficial deposits. These preliminary contacts were then adjusted to honour outcrop data and the interpretation of the bedrock unit immediately below surficial deposits in individual wells. This GIS layer was created at a scale of 1:1,000,000.