- GeoRef, Copyright 2004, American Geological Institute. Reference includes data from Bibliography and Index of North American Geology, U. S. Geological Survey, Reston, VA, United States
Pedestal rocks are mushroom-shaped masses of bedrock possessing structural and lithologic homogeneity and which are produced by differential weathering or erosion. They are thus differentiated from balanced rocks. The separate components of the pedestal rocks are the cap, pedestal or shaft, and base. Pedestal formation begins with exfoliation rounding the corners of a cubical joint block. Wind action undercuts the western face, shifts the crest eastward, and subsequently deflates the entire block. The eastern side of the block is undercut more than the western side due to the effects of hydration and frost action. The final stage is reached when the block is reduced to a relatively flat base.