The Kaibab Limestone is a resistant cliff-forming, Permian geologic formation that crops out across the U.S. states of northern Arizona, southern Utah, east central Nevada and southeast California.

The Harrisburg Member, which forms the uppermost cliffs and receding ledges along both north and south rims of the Grand Canyon, consists of an assemblage of gypsum, dolomite, sandstone, redbeds, chert, and minor limestone.

Originally, geologists interpreted the lower contact of the Kaibab Limestone to be an unconformity based on the presence of local intraformational breccias and erosional surfaces.

[6] However, additional research has concluded that these local intraformational breccias and erosional surfaces are the result of collapse following the dissolution of evaporite deposits within the upper part of the Toroweap Formation.

Within northwestern Arizona, southeastern Nevada, and southwestern Utah this contact is an erosional unconformity that in part consists of paleovalleys, as much as several hundred feet deep, and paleokarst that were eroded into the underlying Kaibab Limestone before the deposition of the Moenkopi Formation.

This disconformity exhibits little relief and is identified by marked differences in color, topography, and rock types between tan, ledge-forming, calcareous sandstones and of the Kaibab Limestone and red, slope-forming siltstones of the Moenkopi formation.

The invertebrate fossils found within the Kaibab Limestone include brachiopods, conodonts, corals, crinoids, echinoid spines, mollusks, hexactinellid and other sponges, trilobites, and burrows of callanassid shrimp.

Relatively minor changes in sea level caused major lateral shifts in the position of supratidal, subtidal, and shallow-marine environments during the deposition of the Kaibab Limestone.

The shifting sea levels and associated depositional environments brought about a complex interlayering of different types of carbonate and clastic sediments in the strata that comprise the Kaibab Limestone.

The gently sloping continental margin on which the Kaibab Limestone accumulated, extended seaward from northern Arizona to southern Nevada, at times exceeding 200 miles (125 km) in width.