POTHOLE (PH)

The pothole arch usually appears as a smooth rounded hole which displays a horizontal opening continuing inward and upward.

CLIFF WALL (CW)

The cliff wall arch occurs on the side or adjacent to rock walls or cliffs. The arch span is separated from the main rock mass to the extent that light can show through the opening.

JUG HANDLE (JH)

The span and opening on the jug handle arch occur on the sides of rock masses at an angle which is normally closer to vertical than horizontal.

EXPANDED CREVICE ARCH (EC)

The expanded crevice arch has its beginnings in a crevice which is usually a bedding plane or joint, then enlarges to where there is a definite light opening.

FREE STANDING (FS)

The free standing arch is distinguished by its relative isolation from surrounding fins, cliffs and other rock masses.

BRIDGE (NB)

Although a natural bridge has many of the same characteristics as other arches, it is distinguished from them by its position astride a stream or stream channel.

SPANNED ALCOVE (SA)

Spanned alcove arches contain a pillar that extends from the outer floor to the outer top of the cave like opening. the pillar conforms geometrically to the slope of the rock mass side.

TUNNEL (NT)

A tunnel arch is more of an elongated arching hole or passageway through the rock. The length of the passageway must be greater than the height or width.

PERFORATED ALCOVE ARCH (PA)

The perforated alcove arch occurs when an alcove has a distinct opening through its rear or side wall.