The Devonian Temple Butte Formation, also called Temple Butte Limestone, outcrops through most of the Grand Canyon of Arizona, USA; it also occurs in southeast Nevada. Within the eastern Grand Canyon, it consists of thin, discontinuous and relatively inconspicuous lenses that fill paleovalleys cut into the underlying Muav Limestone. Within these paleovalleys, it at most, is only about thick at its maximum. Within the central and western Grand Canyon, the exposures are continuous. However, they tend to merge with cliffs of the much thicker and overlying Redwall Limestone. Within the western and central parts of the Grand Canyon, the Temple Butte Formation consists of a westward thickening layer of interbedded dolomite, sandy dolomite, sandstone, mudstone, and limestone that vary in color from purple, reddish-purple, dark gray, to light-gray. Within the eastern part of the Grand Canyon, the Temple Butte Formation fills shallow paleovalleys, which are eroded into the underlying Tonto Group, (upper 3rd unit Muav Limestone). The Temple Butte strata filling these paleovalleys consist of interbedded mudstone, sandstone, dolomite, and conglomerate – that vary in color from purple, reddish-purple, to light gray. Typically, the paleovalley-fill consists of a distinct pale, reddish purple dolomite or sandy dolomite. These paleovalleys range in depth from as much as , to as shallow as . Contacts The upper and lower contacts of the Temple Butte Formation are major unconformities. Within the Grand Canyon region, its base is a major unconformity within the Paleozoic rock record. The time represented by this unconfomity spans about 100 million years, including part of Late Cambrian, all of Ordovician and Silurian, and most of Early and Middle Devonian time. The upper contact is a disconformity that typically consists of nearly horizontal surfaces with little or no relief and overlain locally by a basal conglomerate within the overlying Redwall Limestone. Frenchman Mountain Within the area of Frenchman Mountain, Clark County, Nevada, over of limestone and dolomite occupy the interval between the Muav and Redwall limestones, whereas in the Grand Canyon exist less than of Temple Butte Formation. These limestone and dolomite beds represent sediments that accumulated during the period of time represented by the two disconformities that form the upper and lower contacts of the Temple Butte Formation in the Grand Canyon. Fossils Despite the occurrence of abundant marine invertebrate and vertebrate fossils within the laterally and temporally equivalent Jerome Member of the Martin Formation in central Arizona, the Temple