ABSTRACT

These caves may be roofed by part of the original rock surface, by chockstones, by tilted blocks, and/or by soil andvegetation.

On hillsides and in terrains affected by lateral spreading, gravity eventually begins to widen such crevice caves and form new ones. This occurs more rapidly if an incompetent

or slippery stratum or vulnerable bedding plane underlies a hard, dense formation. Other joints tend to form nearby, and enlarge into crevices. In some caves, they convert unitary crevices into networks. Block sliding, rotation, forward or backward tilting, and/ or basal sapping play roles in determining the predominant form. In complex cases, major crevices commonly are parallel to slopes or cliff faces, with parallel and cross-crevices forming a network or an en-echelon pattern.