Joseph Gleddie, 1954. "Upper Cretaceous in Western Peace River Plains, Alberta", Western Canada Sedimentary Basin: A Symposium; Sponsored by the Alberta Society of Petroleum Geologists, and the Saskatchewan Society of Petroleum Geologists, Leslie M. Clark
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In the light of recent exploratory drilling, some formation boundaries described in the previous paper are redefined and outcrops are correlated with the subsurface. The territory comprises 5,500 square miles of plains area which lies in west-central Alberta, 500 miles northwest of Edmonton. There are approximately 3,400 feet in the west to 2,400 feet in the east, of Upper Cretaceous beds called in ascending order, the upper Shaftesbury, Dunvegan, Kaskapau, Cardium, Wapiabi, and basal Member A of the Wapiti. Recent paleontological studies have shown that in the subject area the base of the Upper Cretaceous may be drawn at the top of the zone containing abundant fish remains which occur in the shales below the Dunvegan formation. The top of this zone is recognized in outcrop, and in subsurface it can be picked at a base line shift toward the left of the resistivity curve of an electric log. It also corresponds with a prominent “in-kick” on a gamma radio-activity log. It is herein suggested that the name “Upper Shaftesbury” formation be applied to the shales between the fish scale zone and the base of the Dunvegan. In this paper, the formational name Cardium is so used to embrace the Bad Heart sandstone.