Difficulties in accurate age determination and correlation of Quaternary age and geomorphic surfaces have been a long-standing problem in Quaternary research (Porter and others, 1983). The

lack of materials appropriate for absolute age determination has caused workers to use various relative dating techniques to correlate deposits of Quaternary age (for example, Burke and Birkeland, 1979). The assumption used in relative dating is that lithology, climate, topographic position, and vegetation factors remain constant among sites so that the weathering of each deposit indicates the time that has elapsed since deposition (and the initiation of weathering processes). However, because lithologic and climatic factors vary between canyons of the east-central Sierra Nevada, conflicting conclusions by different workers at the same canyons and between canyons have resulted (Fullerton, 1986).