The bedrock topography of the Edmonton area can be described as a regional northeast sloping bedrock surface disected by numerous channels of preglacial and glacial fluvial origin. The bedrock surface ranges in elevation from about 900 m in the extreme southwest corner of the map area, to as low as 560 m within the buried Beverly Valley in the northeast corner. Major preglacial valleys in the map area are the Beverly Valley, Onoway Valley, and the Vegreville Valley. From southwest to northeast, the major tributaries of the Beverly Valley include the Stony Valley and its tributaries (Calmar, Devon, and New Sarepta valleys), the Boag Valley, the Ardrossan Valley, the Simmons Valley, and the Lamont Valley. The Sturgeon Valley is the only tributary of the Onoway Valley in the map area. From west to east, the tributaries of the Vegreville Valley include the Ministik, Tawayik, Beaverhill, Holden valleys, as wellas the Whitford Valley which likely joins the Vegreville Valley in the Vermilion map area to the east. A number of poorly defined valleys in the south part of the map area are tributaries of the preglacial Red Deer River valley that lies south of the Edmonton map area. These include the Dusty, Camrose, and Bittern valleys.