This report presents new subsurface stratigraphic picks for the tops of the Horseshoe Canyon, Wapiti and Battle formations in the west-central Alberta Plains (Townships 15 to 67, Ranges 16, West 4th Mer. to 3, West 6th Mer.) made using downhole geophysical well logs. Representative geophysical logs are included to demonstrate the criteria used to make picks and to highlight regional geological variability. Well data were screened to detect errors resulting from deviated wells, as well as incorrect ground and kelly-bushing elevation data. Statistical methods were used to identify local and regional statistical outliers, which were examined individually and either confirmed or removed. Detailed picking helped to delineate areas where the Battle Formation is absent and the top of the Horseshoe Canyon or Wapiti Formation coincides with the base of the overlying Scollard Formation. A structure contour map for the top of the Horseshoe Canyon and Wapiti formations is included to illustrate regional structure.