The Permian redbeds of Kansas are re-studied in detail with reference to Cragin's type sections and original classification, to which correlations have been made for more than 40 years, this paper enlarging on an unpublished paper, "Lower Red-Beds of Kansas," abstracted in the Bulletin of the American Association of Petroleum Geologists, Vol. 21, No. 12 (December, 1937), pp. 1557-58.

The Cimarron series includes all of the Permian redbeds overlying the salt-bearing and gypsum-bearing gray shales of the Wellington formation. From the base upward, the names and thicknesses of the subdivisions are given.

The two lowermost units, the Estheria-bearing Ninnescah shale, 425 feet thick, and the Stone Corral dolomite-anhydrite, 0-6 feet thick (although much thicker in subsurface), have been excluded from Cragin's "Harper sandstones," the latter being here restricted to two higher members: the Chikaskia sandstone, 145 feet thick, and the Kingman sandstone, 80 feet thick. The basal part of the Ninnescah becomes the Garber sandstone in Oklahoma, while its upper part plus the Chikaskia are the equivalent of the type Hennessey of Oklahoma. The Kingman sandstone has been mis-correlated often with the Oklahoma Duncan, a much higher formation.

Cragin's "Salt Plain measures," 275 feet thick and in few places well exposed, has been mis-called "Hennessey shale" in Oklahoma where exposed beneath typical Duncan sandstone. The Cedar Hills sandstone, 180 feet thick, is correlated with the true Duncan of Oklahoma, while the selenite-veined Flower-pot shales, 190 feet thick, have been called Chickasha in Oklahoma. The name "Nippewalla" is suggested for the group of formations lying between the Stone Corral and Blaine evaporites.

Cragin's "Cave Creek formation" is identical with the Blaine formation of Oklahoma, is 84 feet thick, and is divided upward into four beds of gypsum: Medicine Lodge; Nescatunga, a bed in Cragin's "Jenkins clay"; Shimer ("Lovedale" of Noel Evans); and Haskew. Where these gypsums are well developed, only 15 feet of Cragin's Dog Creek shales separate them from the Whitehorse sandstone. At Dog Creek, the type locality, however, with the three upper beds absent because of solution, the separating clays to the base of the "Jenkins" have been included in the 53 feet of Dog Creek shales, the highest unit of Cragin's Salt Fork division of the Cimarron series.

From the base upward, the Kiger division begins with the Whitehorse sandstone, a formation 265 feet thick, the name replacing Cragin's "Red Bluff" (pre-occupied and dropped). It falls into four natural subdivisions or members: Marlow sandstone, 110

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feet thick; Relay Creek dolomites with their included veined sandy shales, 22 feet thick; an even-bedded sandstone, 100 feet thick; and a red shale member, 38 feet thick, with local thin dolomites at middle and base, the last two being equivalent to the Rush Springs-Cloud Chief of Oklahoma, although Cloud Chief gypsums are not recognized in Kansas. No "channel-sands" of the type Verden or type Whitehorse facies of the Marlow have been noted in Kansas, although calcareous, cross-bedded sandstones are found associated with the Relay Creek dolomites.

Capping the Whitehorse sandstone, commonly in a bold scarp, is the "Day Creek dolomite" of Cragin, a single bed of dense, in many places cherty, dolomite 2 feet thick. This bed in turn is overlain by gray and red shales ("Hackberry shales" of Cragin, name pre-occupied, dropped) and "Big Basin sandstone," totalling 65 feet, previously combined under the latter name, which are probably correlative with the lower beds of the Quartermaster formation (restricted) of Oklahoma, these beds terminating the Kansas redbed exposures, with the possible exception of a small exposure in Morton County, not studied by the writer, which is mapped as Triassic by the Kansas State Geological Survey.

Possible horizons of unconformity have been studied critically, the evidence indicating nothing greater than local disconformity, the more pronounced stratigraphic abnormalities ordinarily due to removal of soluble beds by ground waters, resulting in slumpage and collapse-brecciation of the overburden, a condition to be expected of beds in contact with the major dolomite-anhydrite formations, which are the Stone Corral, the Blaine-Dog Creek, and the Day Creek. The excellence of these evaporite formations as key horizons in redbed stratigraphy is emphasized in contrast to the variable lithology of the intervening red siltstones and their included lenses of rounded, frosted, orange-polished or micaceous sandstones, on which scant dependence can be placed, as shown on subsurface cross se tions.

A cross section depicts a progressive wedging-out of the various members of the Wellington and Harper formations westward against the Sierra Grande arch of eastern Colorado, where beds of approximate Salt Plain age rest on beds near the top of the Pennsylvanian (Wabaunsee) as accepted by the Kansas Geological Survey, the one real unconformity of regional significance discovered.