Abandoned Natural Arch
Canyon Arch, Royal
This type of natural arch is invariably isolated and the lintel is
arched. The opening is usually a semicircular aperture, although in
some cases it is an oval aperture. There are two roughly vertical abutments,
each having a vertical rise greater than its horizontal extent.
For many natural arches of this type, the lintel and abutments form
a single strand of rock whose breadth varies little over most of its
curved length. In other examples, one of the abutments is noticeably
broader than the lintel and other abutment, but this broadening is roughly
in the plane of the opening aperture.
Natural arches of this type are considered old, i.e., at the end of
their lifecycle. Although there is no conclusive evidence for a specific
formation process, it is clear that the natural arch continues to survive
due to compression strengthening. Compression
strengthening made the remnant rock more resistant to erosion than
the rock that once surrounded it, and hence, gave it its characteristic
arched shape. This type of natural arch is rare.