Permian System--Wolfcampian Series
The lowermost member of the Barneston formation, the Florence limestone member, is the youngest consolidated rock in Elk County. It caps two small hills in the extreme northwestern part, hence is of little importance as an aquifer.
Florence limestone member--Exposures of the Florence limestone are poor and are covered mostly with fragmental chert weathered from higher parts of the rock. Only the lower few feet of this extremely cherty limestone occurs in Elk County.
Present only in the extreme northwestern part of the county, the Matfield shale has a thickness of 55 to 60 feet.
Blue Springs shale member--The thickness of the Blue Springs shale is about 25 feet. Exposures in Elk County do not allow exact measurements or descriptions, but in neighboring parts of Cowley County this unit contains some thin-bedded fossiliferous limestone interbedded with gray shale in the upper part and about 2 feet of gray-green limestone about 6 feet from the base. The rest is bluish-gray and bright-red shale. The formation is unimportant as an aquifer.
Kinney limestone member--The Kinney limestone holds two fairly prominent benches in the extreme northwestern part of Elk County, where the unit is believed to comprise two limestones separated by a few feet of shale. The total thickness is about 15 feet.
Wymore shale member--The Wymore shale is covered by soil in the small areas of its outcrop in northwestern Elk County. In neighboring parts of Cowley County it is about 9 feet thick and consists of gray and red shale and includes some lavender limestone in its lower middle part.
Like higher beds, the Wreford limestone is poorly exposed. Measurable exposures in the western part of the county are limited to only a few feet of cherty limestone, which occurs in the lower part of the formation, and they are not suited for differentiating the members of the formation. The upper beds generally are reduced to cherty rubble, which blankets the bench held by the formation. The thickness probably is between 30 and 35 feet. The formation is an important aquifer.
Council Grove Group
The thickness of the Speiser shale is commonly about 28 feet, but one section containing only 19 feet was measured. The upper part consists of thin, gray and buff, nodular limestone and shale beds. There is considerable red and green material in the lower part. The upper part is abundantly fossiliferous, and large specimens of Derbyia are plentiful. The formation is of little or no importance as a source of ground water.
Where measured, the Funston limestone ranges in thickness from 11 to 13 feet and consists of two limestones separated by 4.5 to 7 feet of buff, gray, and red shale. Locally, the shale is calcareous and contains nodular, partly fossiliferous limestone. The upper limestone, about 2 to 4 feet thick, is dense and platy to massive. The lower limestone, about 1.5 to 2.5 feet thick, is bluish and commonly contains fossil mollusks and algal remains. The formation is of little or no importance as an aquifer.
Blue Rapids Shale
The average thickness of the Blue Rapids shale is about 23 feet. Thin, locally cherty limestone is fairly characteristic, especially of the upper part. Colors of the shale are gray, greenish, and red. Locally, specimens of the large brachiopod Juresania are common in the upper part, and sparse algal remains occur in the middle and lower parts. Little if any ground water is obtained from the formation.
The Crouse limestone is about 9 feet thick and in most exposures consists (in descending order) of: 2 to 3 feet of yellowish, thin-bedded, platy limestone; 3 to 4 feet of bluish-gray, dense, massive, locally cherty limestone; and about 3 feet of irregular, thin-bedded to nodular limestone, which characteristically contains discoidal fossil algal colonies (Ottonosia), which at least in part are coatings on clam shells. The more massive upper and middle parts of the formation hold a prominent topographic bench along the line of outcrop. A few wells derive water from the Crouse limestone.
Easly Creek Shale
The average thickness of the Easly Creek shale is about 10 feet. The formation is characterized by its distinct brown and red colors and the presence of small white algal masses. This formation is of little or no importance as a source of ground water.
About 28 feet is the average thickness of the Bader formation in Elk County, where it is composed of bluish and greenish-gray, thin-bedded limestone and gray, buff, yellow, brown, green, and red shale. Boundaries of members are defined with some difficulty. Little or no ground water is derived from the Bader formation.
Middleburg limestone member--The Middleburg limestone is about 6 feet thick and consists of gray to greenish, thin-bedded limestone that weathers whitish and is interbedded with gray to greenish shale. The dense, tough limestone commonly contains fossil pelecypods. Its position is marked by a low indistinct bench below the more deeply weathered Easly Creek shale.
Hooser shale member--About 11 feet is the average thickness of the Hooser shale. In descending order it consists of: about 4.7 feet of buff to yellow shale; 0.2 foot of greenish-gray, molluscan limestone; 2.5 feet of interbedded dark-blue to greenish, nodular, fossiliferous limestone and buff shale; and 4.1 feet of varicolored, algal shale, which commonly is poorly exposed.
Eiss limestone member--The thickness of the Eiss limestone is about 11 feet. The upper 2 feet is blue-gray, massive limestone, commonly conspicuously pitted and faded to light gray by weathering. It is underlain by about 2 feet of red and green shale. The rock in the lower part (about 7 feet) is buff and gray thin-bedded limestone, the lowermost part of which is nodular and contains fossiliferous gray shale.
The Stearns shale is about 13 feet thick. It is well exposed in only a few places, but where seen it consists of about 5 feet of gray shale overlying about 6 feet of red and brown shale, which is underlain by about 2.5 feet of bluish to dark-gray shale and nodular limestone. The more brightly colored shale contains small bodies that are believed to be fossil algae. The brachiopods Meekella and Juresania and the pelecypod Aviculopecten occur in the nodular limestone and associated shale. The formation is of no importance as an aquifer.
The Beattie formation consists of two limestone members and a shale member, and it ranges in thickness from about 15 to 29 feet. The formation is of little or no importance as a source of ground water.
Morrill limestone member--The thickness of the Morrill limestone averages about 9 feet, but may be as little as 7 feet locally. The upper part is buff to whitish, irregularly thin bedded limestone, and the next lower unit, commonly about 2 feet thick and 3 to 5 feet below the top, is buff to bluish, massive limestone that weathers with an irregular, pitted, light-gray surface. The lower part is buff to yellowish, thin-bedded, nodular limestone interbedded with yellow fossiliferous shale. Fusulinids and sea-urchin plates and spines are abundant in the massive and lower, shaly parts. Material believed to be of algal origin covers many of the sea-urchin fragments.
Florena shale member--The average thickness of the Florena shale is about 8 feet; a maximum of 14 feet was measured near the Elk-Cowley County boundary between sections 3 and 4, T. 31 S., R 8 E. This unit consists of gray, brownish, and bluish clay shale that is abundantly fossiliferous. Light-gray, argillaceous, nodular limestone in discontinuous beds occurs locally in the upper part where the Florena shale is thicker. The brachiopod Chonetes is the most plentiful fossil, but there is an abundance of other forms, including fusulinids, conodonts, mollusks, bryozoans, echinoderms, and trilobites.
Cottonwood limestone member--The Cottonwood limestone is bluish-gray limestone, interbedded with buff and gray shale, and its average thickness is about 5 feet. Fusulinids are fairly common in the upper part, and gastropods, pelecypods, and productid brachiopods are common in the lower part.
The average thickness of the Eskridge shale is about 23 feet. Gray and red shale and some purplish and greenish limestone are characteristic. The formation commonly is concealed under a grass-covered slope marked by a bench held by distinctive massive limestone beds in its middle part. The Eskridge shale is of no practical importance as an aquifer.
The thickness of the Grenola limestone is about 45 feet. The Neva limestone, uppermost member of the formation, is the most conspicuous part. A few springs issue from the Grenola, and probably a few shallow wells produce water from it.
Neva limestone member--The Neva limestone is about 20 feet thick. There is some shale in the lower part, especially in the southern part of adjacent Greenwood County, but to some extent it grades into nodular and thin-bedded limestone in southern Elk County. The upper part of the unit is composed of massive and thin-bedded limestone. Light gray is the prevailing color. Fusulinids are plentiful.
Salem Point shale member--The thickness of the Salem Point shale averages about 7 feet. Gray to brown shale is the prevalent rock. Some bluish-buff limestone occurs in the upper part, and the middle part is characteristically marked by "limestone box work", a network of calcite veins. A thin, dense, pelecypod-bearing limestone occurs in the lower part.
Burr limestone member--The Burr limestone is about 4 feet thick and consists of two massive, blue-gray to dark-gray dense limestones separated by about 0.2 foot of shale. Fossils include ostracodes, the pelecypod Myalina, and small snails.
Legion shale member--About 5 feet is the common thickness of the Legion shale. It comprises gray to buff shale and a few limestone stringers. This rock is sparsely fossiliferous, containing a few pelecypods and the brachiopod Juresania.
Sallyards limestone member--Measured sections of the Sallyards limestone show a thickness of 3.5 to 4.1 feet. Where best exposed it consists of bluish-gray massive to platy, irregularly bedded limestone that weathers dark gray. Pelecypods, crinoid fragments, and bryozoans are common.
The Roca shale is about 15 feet thick. The upper few feet is gray to brown shale that in some places contains small white to cream-colored nodules, which are believed to be fossil algae. The rest of the formation commonly is red to purplish shale, but in some exposures the lower-most part is green, gray, or brown. This formation commonly is concealed under a grass-covered slope. The formation is of little or no importance as a source of ground water.
Red Eagle Limestone
The Red Eagle limestone is about 19 feet thick. The formation consists almost entirely of limestone, but members recognized farther north in Kansas and in southern Nebraska are differentiated (O'Connor and Jewett, 1952). Exposures in Elk County are sparse; an outcrop in sec. 4, T. 31 S., R. 8 E., affords the best opportunity for study. The formation is of little or no importance as an aquifer.
Howe limestone member--The Howe limestone is 2.5 feet thick. It is buff and chalky and occurs as a massive bed. Recognizable fossils are minute foraminifers and minute gastropods.
Bennett shale member--The Bennett shale is represented almost entirely by a limestone facies. The measured thickness of the member is 19.9 feet. All except the lower 0.3 foot of the unit is coarsely crystalline gray limestone that weathers buff. It occurs in irregular well-jointed beds a few inches thick, and the lower part is somewhat nodular. The lowest 0.3 foot is gray, silty shale, containing rusty-brown fragments of Orbiculoidea.
Glenrock limestone member--The lowermost member of the Red Eagle formation is a silty, nodular, gray, fusulinid-bearing limestone 0.2 foot thick.
The thickness of the Johnson shale is about 20 feet. Where best exposed the upper 7 feet is bluish-black shale including several thin, blue, dense, nodular limestone beds. This is underlain by 1.9 feet of yellowish, vuggy, earthy limestone, containing a profusion of variously oriented calcite veins, which stand out in relief on weathered surfaces producing a honeycomb, or "boxwork", effect. In the upper part, ostracodes, pelecypods, and productid brachiopods are abundant, and other fossils are common.
The Foraker limestone is a cherty limestone and shale formation about 55 feet thick carrying a prolific fusulinid fauna. This formation is the main aquifer in the northwest part of Elk County.
Long Creek limestone member--The Long Creek limestone is about 6 feet thick. The upper part, about 1 foot, is gray to tan, tough limestone that weathers nearly white to bright yellow orange and is believed to be mostly algal. At exposures in southern Greenwood County, the middle part of the unit is seen to consist of brown and gray shale that is platy in its lower part. The lower part is dark-gray to bluish, fusulinid-bearing limestone and includes a thin algal zone at the top. In Elk County the Long Creek limestone is commonly present on gentle slopes at a considerable distance west of the escarpments held by thicker limestones in the same formation. Consequently, exposures are generally poor.
Hughes Creek shale member--The Hughes Creek shale is about 40 feet thick and consists mainly of dense, gray, massive, cherty, fusulinid-bearing limestone and dark-gray, blue-gray, and yellow-gray, fossiliferous shale. About one-half of the thickness of the unit is shale. The limestone, unlike the shale, is fairly well exposed and bears abundant fusulinids in both the chert nodules and the calcareous matrix. Other fossils include ostracodes, crinoid fragments, bryozoans, brachiopods, pelecypods, and conodonts.
Americus limestone member--The thickness of the Americus limestone ranges from about 7.5 to 11 feet. The unit comprises two limestones separated by shale. In the northern part of the county, the upper limestone is about 1.6 feet thick, blue gray, massive, and cherty. The separating shale is about 4.5 feet thick, bluish to yellow, and contains some platy to nodular limestone beds in the lower part. The lower limestone is about 1.4 feet thick. It is bluish gray and consists of two beds, the lower of which contains thin zones of gray to tan limy pebbles. In the southern part of Elk County, the upper part consists of blue-gray, massive limestone about 3.5 feet thick. The shale, in the middle part of the unit, is about 4.5 feet thick and is blue gray to black. Locally, it is almost coaly. A few blue limestone stringers are in the shale. The lower limestone, about 2 feet thick, is bluish gray, massive, and contains tan and gray limy pebbles in the lower part. In the upper part it has irregular thin beds, and fusulinids are abundant.
In Elk County the Janesville shale is about 70 feet thick. It comprises two shale members separated by a limestone member in the middle part.
Formerly, strata now recognized as the Janesville shale (Moore and Mudge, 1956, page 2273 and fig. 1) were classed as three separate formations (Hamlin shale, Five Point limestone, and West Branch shale) that now are regarded as members of the Janesville formation.
Hamlin shale member--The Hamlin shale is about 35 feet thick. It comprises two shale units separated by a limestone near the top. The upper part is the Oaks shale bed, which ranges from about 3 to 7 feet in thickness and averages about 6 feet. There are few exposures of this part of the Hamlin shale in Elk County, but where seen it is brownish in the upper part grading through yellowish into dark gray or nearly black; or the persistent brown part is underlain by thin, yellow-gray limestone, which overlies yellow and bluish platy shale. In turn, this latter is separated from greenish shale below by a thin bed of limestone. Small white nodules in the brown shale in the upper part of the Hamlin are believed to be fossil algae.
A limestone bed is the middle unit in the Hamlin shale. This unit is believed to be the Houchen Creek limestone. Its thickness is about 3.5 feet. It is bull to orange yellow, earthy, and shaly, and it is characteristically marked by well-developed calcite veinwork, which stands out in relief as pronounced "boxwork" where weathered.
The lower part of the Hamlin shale was formerly known as the Stein shale member of the Hamlin formation. The strata have a thickness of about 32 feet. Where best exposed, they grade from gray to yellow shale in the upper few feet to the green and red material that constitutes most of the unit. The lower part consists of yellow to orange and gray shale overlying greenish-gray, blocky shale. Locally, there is a well-developed "boxwork" of calcite and some silty, crinkly, thin-bedded limestone in the middle part.
Five Point limestone member--This limestone is about 2 feet thick, dark to brownish gray, and weathers to yellow orange. It is massive and at the outcrops commonly is broken down into two or three irregular beds. Fusulinids are abundant, and brachiopods and bryozoans are common.
West Branch shale member--Measured sections of the West Branch shale range from about 20 to 36 feet in thickness. A thin bed of coal occurs about 8 to 14 feet below the top. The upper part of the formation is greenish-gray shale, which grades downward into bluish-gray to black shale containing some greenish material. Yellow to tan calcite "boxwork" and limestone stringers occur locally in the lower part.
Falls City Limestone
The Falls City limestone is 2 to 3 feet thick. It is earthy to dense, dark-blue to yellowish-gray limestone containing numerous joints filled with calcite. In some places, the lower part is massive and the upper part is nodular; in other places, the unit consists of three or more nearly uniform beds. Most of the fossils are fragmentary. Composita, Meekopora, bellerophontid gastropods, and crinoids are most common.
The Hawxby shale, Aspinwall limestone, and Towle shale formerly were classed as individual formations, but according to present classification (Moore and Mudge, 1956),they are regarded as members of the Onaga shale, which in Elk County has an average thickness of about 20 feet.
Hawxby shale member--The thickness of this unit ranges from about 6 to 8 feet. The upper part is gray and locally contains micaceous sandstone. The lower part is red, purple, green, and yellow. Locally, a thin, bluish-gray, nodular limestone, believed to be algal, is present next below the upper gray part.
Aspinwall limestone member--The average thickness of the Aspinwall limestone is 2 feet. Locally, about 0.6 foot of shale occurs between the upper and lower parts. Exposures in Elk County are poor, but where best seen the unit is thin-bedded to slabby and dark gray. It contains a mixed molluscan-bryozoan-brachiopod fauna.
Towle shale member--The Towle shale has an average thickness of about 20 feet. It commonly consists of yellow to gray micaceous shale, which weathers greenish gray. Locally, the upper part contains several thin bluish limestone beds interbedded with gray and tan shale. Physical evidence of disconformity at the base of the Towle shale was not observed in Elk County.
The Admire group of rocks is of only minor importance as aquifers. Locally, small amounts of water are obtained from relatively shallow dug wells.
Kansas Geological Survey, Geology
Web version July 2002. Original publication date July 1958.
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