As erosion removes rock material from the surface of the land, the underlying rocks are under less pressure. As the pressure is lowered on them, the rocks expand upwards, creating fractures subparallel to the land surface. Slabs of rock then 'peel off' along the fractures, creating domical hills. Famous 'Half Dome Mountain' is an example of an 'exfoliation dome.'

© 2001
Photo by David J. Leveson