The Geology of Denton County

"  Kiamitia. This formation, which represents the close of the time period represented by the life forms in the Goodland, from the standpoint of historical geology may be considered as simply the final phase of the Goodland. The fossils with but a few exceptions are those of the Goodland and very few of the species seen in the Kiamitia persist into the overlying Duck Creek.  The Kiamitia is composed mainly of clays containing some calcareous material with occasional thin ledges of sandy limestone. The upper portion contains less clay and is distinctly calcareous. It contains large numbers of a peculiar and characteristics oyster, Gryphea navia, which, as previously noted, at Denison and other points along the Red River sometimes forms a shell conglomerate. The clays of the Kiamitia are black and waxy, contain much organic matter, and in some seams a considerable proportion of pyrite of iron. Presence of this pyrite, which weathers into limonite or hydrated iron oxide, gives a peculiar yellow-brown appearance to all weathered exposures of the Kiamitia. After torrential rains when the weathered material has been removed the black waxy shales become visible and these shales are always conspicuous in well borings.  The thickness changes in the Kiamitia are the reverse of those in the Goodland as this formation thins rapidly to the south and to the southwest. This formation is 42 feet thick in western Denton County, thins rapidly to the south and disappears entirely at the Brazos. Doubtless this thinning is due to the replacement of the lower portions of the Kiamitia away from the shore line by the limestones of the Goodland. The upper or Gryphea navia member persists and is recognizable beyond the Brazos.  "

• Stratigraphy of the Kiamichi Formation in Tarrant County, Texas by Winton and Adkins

The Geology of Texas - Vol. 1

KIAMICHI FORMATION

Nomenclature. -- The formation was first called Kiamitia clays by Hill (722, p. 515) in 1891. The present spelling is the product of the Board of Geographic Names. The type locality is the plains of Kiamichi River near Fort Towson, eastern Choctaw County, Oklahoma, though Hill also mentions several typical localities west of that place.

Stratigraphic position and contacts. -- Information on the contacts of this formation is meager. In the Fort Worth area, rounded pebbles have been taken from the upper contact, and the washed material at this level shows much grit and transported debris (Winton and Scott, personal communication). South of McLennan County, the formation is absent, and there are evidences of lack of conformity at the Edwards-Duck Creek contact. Writers have noted the sharp lithologic break at the lower contact, but definite records of the nature of this contact are lacking. The formation is well exposed at Marshall's Bluff, Grayson County, and at the Texas and Pacific Railway crossing of the Clear Fork, west of Fort Worth.

Facies. -- The formation, to its southern disappearance, is neritic, and consists of marls, thin limestone seams, and shell aggregates (mostly of Gryphaea navia Hall, some loose, some cemented). If the Sierra Prieta sandstones below the Duck Creek Desmoceras zone include the Kiamichi, it occurs there in the marginal facies.

Areal outcrop, local sections.-- At the outcrop, the formation is limited to central Texas north of the Brazos, and to the northern (more neritic) facies in Trans-Pecos Texas. Its easternmost outcrop is at Cerrogordo, Arkansas, its westernmost outcrop in Texas opposite the smelter at El Paso. There may be equivalents in southern New Mexico and in Arizona; its zone fossils occur near Lampazos, Nuevo Leon, and in the Sierra de Tamaulipas, eastern Mexico. Northwards it occurs in the Texas Panhandle, western Oklahoma, southern and central Kansas, Colorado, and northeastern New Mexico. In wells it is practically unrecorded, except near the outcrop.

One-half mile north of Cerrogordo, the Kiamichi consists of a few feet of one-foot beds of closely packed gryphaeas, set in a scant matrix of dense, hard, gray-green marl, and alternating with poorly exposed, softer, gray and green marls, containing Gryphaea navia. One-half mile northeast of Cerrogordo, 20 feet of Kiamichi consists of blue-gray and green-gray marls alternating with discontinuous beds and lenses of gray fossiliferous limestone. Near Goodland, Choctaw County, Oklahoma, Hill (803, p. 253) records 150 feet of Kiamichi. The formation in this region consists of shelly marl and indurated shelly limestone ledges in such quantity as to be commercially suitable for lime and road metal. The formation, as in the valley of Kiamichi River, contains countless Gryphaea navia and G. corrugata, together with other undescribed fossils. The first Comanchean fossil to be described from the Texas-Oklahoma region was G. corrugata Say 1823, collected by the botanist Nutall in the lower Kiamichi River valley; the second, Gryphaea pitcheri Morton 1834 (=G. corrugata Say 1823) was collected in 1833 by Dr. Z. Pitcher from near Fort Towson, eastern Choctaw County, Oklahoma (796, pp. 33-34). In Bryan County, Taff records about 55 feet of Kiamichi (Taff, Atoka folio, No. 79, p. 6, 1902); in Marshall and Love counties Bullard records 35 to 36 feet. In Grayson County, thicknesses of 33 feet (803, p. 254), 36 feet (177, p. 25), 40 to 50 feet (844. p. 3), and 61 feet (Emil Böse, personal communication) are on record. The upper ledges of the Kiamichi occur at the Duck Creek type locality (803, p. 254), where the ammonite partition (ranges of Oxytropidoceras, Adkinsites, Elobiceras, and Pervinquieria) is well exposed. Along the outcrop to the Brazos, the following thicknesses are recorded: northern Cooke County, 36 feet; 2 1/2 miles southwest of Era, 30 feet; southern Cooke County, 20 feet; western Denton County, 42 feet; Montague County, Sunset, 44 feet; at Rhome, 35 feet; northwest corner Wise County, 22 feet; Dallas County, nothing identifiable; Tarrant County, 27 feet; Johnson County, 18 feet; near Blum, Hill County, 19 feet; near Mexia, 13 to 16 feet; Bosque County, 3.6 miles east of Valley Mills, 10 feet; at the McLennan-Bosque county line, 9 feet; McLennan County, on the North Bosque, southwest of China Springs, 5 feet; near Whitson, Coryell County, less than 5 feet; in Bell County and southwards, unknown.

In Grayson County, the formation consists of an alternation of shale or clay with limestone or shelly bands. The indurated calcareous clay occurs interstratified with the dark blue clay; laminated limy flags in the lower half and indurated Gryphaea shell-ledges in the upper half alternate with the clay. In the northern area, the hard ledges are continuous between exposures. They seem to be composed of Gryphaea corrugata Say, with some other species less abundant. In Tarrant County the basal half of the formation is marly. The next one-fourth contains 6 thin limestone ledges alternating with marl. The top is marly, but on the Red River it is shelly. Near Fort Worth, G. navia is abundant in the middle third, and sparse above, but on Red River it forms shell aggregates in the top of the formation. Exogyra plexa occurs in the base of the upper one-third (and in the Goodland limestone). Oxy. belknapi, abundant at Fort Washita and at the Duck Creek type locality, seems to characterize the formation. Oxy. "acutocarinata" is also reported from the formation. In the Fort Stockton area G. navia is confined to the base, and G. corrugata is the abundant species above. South of Tarrant County the shell aggregates largely disappear and the limy ledges are reduced. Gryphaea corrugata, Exogyra plexa, and Oxy. belknapi seem more frequent in the top; G. navia and Exogyra texana in the base. Toward the Brazos, the dwindling Kiamichi is reduced to a thickness of less than 10 feet, mostly of marl; its southermost appearance is in Coryell County, near Whitson.