The breached-dam hypothesis for the formation of the Grand Canyon needs physical evidence for the justification of extinct lakes. Digital elevation data were used for basin and proposed lake shore mapping and for cliff identification on the Colorado Plateau upstream from the Grand Canyon. Satellite images, aerial photographs, and visual searches from aircraft were used to confirm cliff locations in a search for shore line cliffs that might exhibit the missing talus phenomenon. The distributions of mapped Pliocene and Pleistocene sediments show that some may be related to the hypothesized extinct lakes. Although not proving the case for such lakes, the findings are consistent with the hypothesis.
