The previously described Pennsylvanian rocks do not crop out in Brown County but crop out in eastern and southeastern Kansas. Rocks of Pennsylvanian, Permian, and Pleistocene ages crop out in Brown County (Table 2, Pl. 1). The Pennsylvanian and Permian rocks in Brown County are largely concealed by a mantle of Pleistocene glacial drift or loess. Bedrock outcrops are confined essentially to the major stream valleys with glacial drift and loess covering the interstream areas (Pl. 1). Alluvial deposits are widespread in the valleys of the larger streams.
Table 2--Generalized section of outcropping rocks in Brown County, Kansas. In this report small supplies refers to yields generally less than 10 gpm, moderate supplies to 10 to 100 gpm, and large supplies to more than 100 gpm.
|0-55||Alluvial deposits of silt, clay, sand, and gravel within the valley walls of the major streams. Gravel composed of limestone, chert, and glacial material.||Yields small quantities of water to wells where saturated.|
|Loess||0-86||Wind deposited silt generally in an upland position. Locally may contain silt older than Wisconsinan age.||Yields no water to wells in the County.|
|0-100||Includes outwash deposits and glacial till. Outwash deposits consist of silt, clay, sand, gravel, and scattered boulders. Generally the sand and gravel is poorly graded but contains less silt and clay than the alluvial deposits of Recent and Wisconsinan age. Glacial till consists of a heterogeneous mixture of silt, clay, sand, gravel, and boulders. Clay is the most common grain size present. Lenses of relatively clean gravel may be locally present.||Yields moderate to large supplies of water from outwash deposits where they lie below the water table, and small to moderate supplies of water to wells from glacial till in most areas. Locally, the till yields no water to wells.|
|0-50||Consists of fine to very fine sand and silt. Well graded and thinly laminated. Occurs only in buried valleys.||Yields no water to wells in the County although it lies below the water table.|
|10-20||Chert gravel. Contains no glacial material.||Yields no water to wells in the County. Potential yields up to 100 gpm are available.|
|10-12||An upper limestone is tan, hard, and blocky to platy. The shale below is tannish-gray, Calcareous and blocky. A lower limestone is a hard, gray, massive, fossiliferous limestone.||Yields no water to wells in the County.|
|16-19||Silty, calcareous, grayish-green and maroon shale. Contains Fome thin calcareous beds and tan shale in the lower part.||Yields no water to wells in the County.|
|4||The upper limestone is hard, massive, and light gray. The shale member is silty, calcareous, tannish-gray in the upper part and grayish-green in the lower part, and contains thin beds of limestone. The lower member consists of two limestone beds separated by a tannish-gray, silty, calcareous shale.||Yields no water to wells in the County.|
|15||Silty, calcareous, tannish-gray shale in the upper part and grayish-green shale in the lower part. Contains some limestone in middle part.||Yields no water to wells in the County.|
|3||The upper limestone is porous and gray to tannish-gray. The shale member is silty, very calcareous, tannish-gray, thin-bedded, and very fossiliferous. The lower limestone is a massive, light-gray limestone containing chert nodules and numerous fusulinids, which locally forms hillside benches.||Yields small supplies of water to wells and springs in local areas from solution channels in the Cottonwood Limestone Member.|
|28-32||Clayey, calcareous shale, principally tannish-gray, but contains maroon zones in middle and lower parts and a persistent limestone bed in the upper part.||Yields no water to wells in the area.|
|11-14||The uppermost member is composed of alternating beds of limestone and shale, the top bed of which is a thick porous limestone which weathers brown. This bed is underlain by hard tannish-gray limestone beds and dark-gray shale beds. The shale below the top member is grayish-green and tannish-gray, silty and calcareous. The middle member is composed of two or more thin, hard, gray limestones separated by tan calcareous shale. The underlying shale member is thin-bedded, gray, and calcareous. The lower limestone member is a hard, gray, fossiliferous limestone.||Yields small to moderate supplies of water to wells and springs in the western part of the county.|
|30-35||Clayey, calcareous, gray and tannish-gray shale. Locally contains very dark-gray shale in lower part and a porous, cellular limestone in the middle part.||Yields moderate to large supplies of water from the porous limestone in northwestern Brown County.|
|1-1.5||The upper limestone is soft, clayey, porous, and weathers tan. The shale member is gray to dark-gray in the upper part and black in the lower part. The lower limestone is hard, gray to dark-gray, and very fossiliferous.||Yields small quantities of water to wells from the upper limestone.|
|5-7||Shale, platy, gray, tannish-gray and very dark-gray, and thin-bedded.||Yields no water to wells in the County.|
|6-8||The upper member is a soft, massive, impure, gray to tannish-gray limestone. The shale member is composed of gray, silty, calcareous shale and contains several persistent limestone beds in the upper and middle parts. The lower member is composed of two limestone beds and a shale bed: the upper limestone is hard, gray and fossiliferous; the lower limestone is variable in lithology from hard and massive to shaly.||Yields small to moderate supplies of water from the upper limestone, generally high in sulfates.|
|40||The upper shale member is clayey, gray to tannish-gray, and locally contains celestite in joints and cracks; the lower part of this shale is sandy and contains sandstone lenses. The limestone member is a hard, dark grayish-brown limestone containing numerous fossil fragments and below this is a hard, gray, dense limestone which weathers platy. The lower shale member is composed of gray to grayish-green, and tan, clay shale.||Yields small quantities of water locally to wells from sandstone in the Hamlin Shale Member.|
|2-6||Yields no water to wells in the County.||An upper limestone is a porous coquina of pelecypod shell fragments having a rough surface. The shale below is tannish-gray, clayey, and noncalcareous. A lower limestone is impure shaly and generally cannot be distinguished from the underlying Hawxby Shale.|
|10||The upper shale member is silty, calcareous and tannish-gray. The limestone member is thin, light-gray to tannish-gray, and hard. The lower shale member is tannish-gray, and noncalcareous, containing a dark-gray zone near the middle.||Yields no water to wells in the County. Small quantities of water are available from sandstone in the Towle Shale Member.|
|17-20||The limestones are gray to dark grayish-brown, hard, and fossiliferous. Shales are gray to grayish-brown and silty to sandy, with some sandstone locally.||Yields small quantities of water from sandstone in the Pony Creek Shale Member.|
|45-50||Gray to bluish-gray noncalcareous, sandy shale at the top of the formation separated from gray, sandy, calcareous shale by a thin, hard, blue to bluish-gray limestone. Coal occurs in the upper part of both shales.||Yields small supplies in local areas from sandy shale.|
|8-12||Hard, massive, tannish-gray, fossiliferous limestone and calcareous, sandy, gray to dark-gray shale locally containing sandstone.||Yields small supplies in local areas from sandy shale and sandstone in the Dover Limestone.|
|15-25||Noncalcareous, gray to grayish-green, sandy shale. Locally contains sandstone.||Yields small amounts of water from sandstone.|
|16-20||Upper limestone is hard, gray to tannish-gray, vertically jointed, and fossiliferous. The shale member is silty, noncalcareous, and contains a thin coal bed near the top. The lower limestone is hard, massive, grayish-brown, and fossiliferous.||Yields no water to wells in the County.|
|30||Noncalcareous, sandy, micaceous, gray to tannish-gray shale. Locally contains sandstone in the upper part.||Yields small quantities of water locally from sandstone beds.|
|35-40||The upper limestone is hard, bluish-gray to grayish-brown and fossiliferous; locally pelletal in lower part. The shale member is gray to grayish-green. The lower limestone member is hard, dense, grayish-brown, and locally weathers into several beds separated by shaly limestone.||Yields no water to wells in the County.|
|34||Gray to light-gray shale, limy and platy in lower part, silty in middle part, and limy in upper part. Contains a persistent black platy shale in the middle part.||Yields no water to wells in the County.|
|30-32||The upper limestone is a hard, bluish-gray to brown, dense, fossiliferous limestone. The shale is gray to greenish-gray and locally contains a concretionary zone near the base. The lower limestone is composed of several limestone beds separated by shale.||Yields small supplies of water to wells and springs locally.|
|75||The limestones are fossiliferous, thin, and impure and may be locally absent. The shale members are silty, sandy, and locally contain sandstone. A persistent coal occurs near the top of the middle shale member.||Small supplies are available from the sandstone and sandy shale.|
Pennsylvanian System--Upper Pennsylvanian Series
The Wabaunsee Group in Brown County consists of about 400 feet of limestone, shale, sandy shale, sandstone, and coal. The limestones of the Wabaunsee Group are thinner than those of older Pennsylvanian strata or of the Council Grove Group of Permian age and characteristically weather to a tan or brown color. The shales of the Wabaunsee Group are generally tan, green, or gray, and contain channel sandstone and coal.
All but the lower two units of the Wabaunsee Group, the Severy Shale and the Howard Limestone, crop out in Brown County and are described on the following pages.
The five members of the Scranton Shale (Pl. 1) are, in ascending order, the White Cloud Shale, Happy Hollow Limestone, Cedar Vale Shale, Rulo Limestone, and Silver Lake Shale. The Happy Hollow and Rulo limestone members are lenticular in this area and are locally absent. Where the Happy Hollow is absent, the White Cloud and Cedar Vale cannot be differentiated. Where the Rulo is absent the contact between the Cedar Vale and Silver Lake is placed at the top of the Elmo coal which occurs at or near the top of the Cedar Vale Shale Member. About 75 feet of the total thickness of the Scranton Shale is exposed in Brown County.
The White Cloud Shale Member consists of gray, bluish-gray, and some tan shale, sandy shale, and locally some sandstone. The only exposures of the Member in the county are in the Wolf Creek valley near Robinson. The base of the Member is not exposed, and the probable thickness of the unit is about 20 to 25 feet. No wells are known to produce water from the White Cloud, but small supplies probably could be developed from the sandstone which occurs locally. [Note: In this report, small supplies refers to yields generally less than 10 gpm, moderate supplies 10 to 100 gpm, and large supplies to more than 100 gpm.]
The Happy Hollow Limestone Member is generally a single tannish-brown bed of impure limestone, less than 1 foot thick, containing fusulinids and a brachiopod fauna. The Happy Hollow appears to be lenticular in Brown County and may be absent in local areas. The unit is best exposed in the Wolf Creek valley in the vicinity of Robinson. It does not yield water to wells in the area.
The Cedar Vale Shale Member, which overlies the Happy Hollow, is composed of beds of bluish-gray to tannish-gray shale, gray clay, sandy shale, and some sandstone. The Elmo coal occurs near the top of the Cedar Vale. This coal, which commonly is 12 to 18 inches thick, but has been reported to be as much as 30 inches thick locally, has been extensively mined in the Roys Creek area in northeastern Brown County and in Wolf Creek valley near Robinson (Schoewe, 1946). Most of the mining occurred many years ago, and since about 1934 little mining has been done except by individuals for personal use. No wells are known to produce water from the Cedar Vale, but small supplies are probably available from the sandy shale and sandstone in the unit.
The Rulo Limestone Member is a single bed of hard, gray, fossiliferous limestone, which is lenticular and locally absent. In Brown County the Rulo ranges in thickness from 0 to about 3 feet. No water is obtained from this unit in Brown County.
The Silver Lake Shale Member comprises the strata between the top of the Rulo Member and the base of the Burlingame Limestone Member of the Bern Limestone. The Silver Lake consists of gray, grayish-green, and tan shale. The shale is silty to sandy and locally contains a channel sandstone. Commonly the Silver Lake ranges in thickness from 20 to 25 feet, but thicknesses of sandstone of 25 to 30 feet have been observed, making the total thickness considerably more than is normal for this unit. Small supplies of water are available from the sandstone in the Silver Lake, but no wells are known to utilize this aquifer.
The Bern Limestone consists of three members which, in ascending order, are the Burlingame Limestone, the Soldier Creek Shale, and the Wakarusa Limestone. The thickness of the Bern Limestone in Brown County is about 30 to 32 feet.
|Section through the Bern Limestone and Auburn Shale in SW NW NW sec. 16, T 3 S, R 18 E, exposed in road ditch on a north-facing hill.||Thickness,
|Reading Limestone Member|
|Limestone, impure, earthy, light-gray, blocky, contains large Allorisma||0.5|
|Shale, gray and buff, platy in part; contains many thin limy zones||12.8|
|Shale, light-gray; contains many very thin beds of limestone||6.9|
|Shale, black, fissile to platy, limy at base||0.4|
|Shale, light-gray, not bedded; has appearance of loess||31.0|
|Shale, light-gray to gray; contains a persistent 1-foot bed of limestone 2 feet above base and 0.2-foot-thick limestone 5.8 feet above base||11.0|
|Wakarusa Limestone Member|
|Limestone, bluish-gray on fresh break, weathers grayish-brown, breaks down into chips and small blocks||1.0|
|Limestone, dark bluish-gray on fresh break, weathers brown; contains many crinoids, fusulinids, and algae||1.7|
|Shale, gray, platy||1.1|
|Limestone, brown, impure, breaks into chips and blocks; contains a few brachiopods and crinoids||0.5|
|Shale, gray, well-bedded; contains no fossils||2.2|
|Limestone, grayish-brown, blocky to earthy, no fossils||0.6|
|Soldier Creek Shale Member|
|Shale, gray, well-bedded and jointed||5.5|
|Burlingame Limestone Member|
|Covered interval (in nearby exposures contains a 1.3-foot limestone encrusted with algae and underlain by 0.8 foot of gray shale)||2.1|
|Limestone, light-brown; contains brachiopods and crinoids||1.0|
|Limestone, gray, impure, weathers into chips and small blocks, few fossils||0.5|
|Limestone, contains limonite concretions in upper part, grayish-brown on fresh break, weathers reddish-brown, upper surface irregular||2.0|
The Burlingame Limestone Member consists of several limestone beds separated by thin beds of shale. The lower limestone can be separated into two beds, the lowest of which has an irregular upper surface, contains limonite concretions, and weathers reddish-brown. This bed is overlain by a thin bed of limestone that is lighter in color and weathers into small chips and blocks. The limestone is in turn overlain by a grayish-buff shale, that ranges in thickness from about 1 foot to 8 feet. The shale is overlain by a light-brown, fossiliferous limestone about 1 foot thick. Overlying this limestone is a thin, gray, clayey shale that is overlain by a thin, tannish-gray limestone encrusted with algae. The aggregate thickness of the Burlingame ranges from about 8 to 11 feet in Brown County. Only small quantities of water are obtained from it.
The Soldier Creek Shale Member is a gray, thin-bedded shale. Joints in the shale are present in most outcrops, and the shale adjacent to the joints is stained with limonite. The thickness of the Soldier Creek in Brown County is about 10 feet. The unit does not yield water to wells in the area.
The Wakarusa Limestone Member consists of several limestone beds separated by thin beds of shale. The lower limestone is a thin-bedded, gray, blocky to earthy, nonfossiliferous limestone about 0.6 foot in thickness. This limestone is overlain by a thin-bedded gray shale about 2 feet in thickness. The shale is overlain by a brown, impure limestone about 0.5 foot thick which contains a sparse brachiopod fauna. Next above is a gray, platy shale about 1 foot thick. This shale is overlain by a 2.7-foot limestone which is bluish-gray at the top and dark bluish-gray in the lower part. The lower bed contains crinoids, large fusulinids, and algae. The aggregate thickness of the Wakarusa is about 7 feet. No water is obtained from this unit.
The Auburn Shale is about 34 feet thick in Brown County. In this area the Auburn may be divided into three lithologic units or zones. The lower zone is a gray to light-gray, platy shale containing a persistent limestone bed near the middle and another limestone near the base. The middle zone is a massive, silty, light-gray shale which on some outcrops resembles loess and on other outcrops a well-cemented mudstone. The upper zone is a gray, platy shale containing numerous thin limestone beds that are commonly quite fossiliferous. Between the upper platy zone and the middle (loess-like) shale, a black fissile or platy shale 0.2-foot to 0.4-foot thick occurs. This fissile shale, although thin, is very persistent and makes an excellent marker bed for identification of the Auburn Shale. The Auburn yields no water to wells in the area.
The Emporia Limestone (Pl. 1) consists of three members, which in ascending order are: the Reading Limestone, the Harveyville Shale, and the Elmont Limestone. The thickness of the Emporia in Brown County is 35 to 40 feet.
The Reading Limestone Member is composed of three or, locally, four limestone beds separated by thin beds of shale having an aggregate thickness in the county of 4.5 feet to 6.5 feet. The lower limestone bed is a soft, bluish-gray limestone ranging in thickness from 0.5 foot to 1 foot. This bed contains a brachiopod fauna and very large Allorisma. The lower limestone bed is overlain by a gray, thin-bedded shale which rarely exceeds 1 foot in thickness. This is generally overlain by a dark-gray thin-bedded shale which locally contains a very dark-brown fossiliferous limestone at the top. The upper limestone bed of the Reading is a dense, hard, bluish-gray limestone which weathers grayish-brown to brown. This bed contains fusulinids, crinoids, and brachiopods. The Reading yields no water to wells in Brown County.
|Section through the upper part of the Auburn Shale, and the Reading Limestone Member and the lower part of the Harveyville Shale Member of the Emporia Limestone in NW SW SW sec. 4, T 4 S, R 18 E. Exposed in road cut about 1,000 feet north of corner.||Thickness,
|Glacial drift--Interstratified till and outwash gravel||10+|
|Harveyville Shale Member|
|Shale, gray, clayey; contains thin limestone beds and some siltstone||12.0|
|Limestone, grayish-brown, blocky, few fossil fragments||0.8|
|Shale, dark-gray to grayish-green||0.8|
|Shale, light-gray to buff; contains a thin micaceous sandstone in upper part||14.8|
|Reading Limestone Member|
|Limestone, dark-brown, upper surface very even, lower surface uneven; contains fusulinids, crinoids, and brachiopods||2.5|
|Shale, red and gray||1.0|
|Limestone, dull gray, weathers brown; contains many fossil fragments||0.3|
|Limestone, soft, impure; contains large Allorisma and some brachiopods||0.5|
|Shale, gray, limy and platy in lower part||15.0|
|Shale, black, fissile to platy||0.5|
The Harveyville Shale Member includes the strata between the top of the Reading Limestone Member and the base of the Elmont Limestone Member. The Harveyville is composed of bluish-gray and tannish-gray clayey shale and has a thickness of 32 feet in Brown County. It contains a bed of limestone as much as 2 feet thick near the middle of the unit and, locally, a thin-bedded sandstone a few feet below this limestone. The Harveyville does not yield water to wells.
The Elmont Limestone Member in Brown County is composed of two limestone beds separated by a thin shale bed. The Elmont ranges in thickness from 3 to 5 feet. The lower limestone bed is grayish-brown and contains fossil fragments. Locally, this lower bed is pelletal or conglomeratic. The shale separating the upper bed from the lower bed is clayey, calcareous, and gray. The upper limestone is bluish-gray and fossiliferous and weathers to a grayish-brown color. Small fusulinids and brachiopods are the most common fossils. The Elmont yields no water to wells in the county.
The Willard Shale overlies the Elmont Limestone Member of the Emporia Limestone in Brown County (Pl. 1) and has a thickness of about 30 feet. The Willard is composed of noncalcareous, sandy, micaceous, gray to tannish-gray shale and commonly has one or more sandstone beds near the top. The lower part of the Willard is poorly exposed in Brown County; it forms the covered slope between the Emporia and Zeandale limestones. The upper part of the Willard is generally composed of sandstone exhibiting various degrees of cementation. In some outcrops the sandstone is almost a loose sand, while in other exposures it is well cemented and appears massive. Small quantities of water are available to wells from the sandstone in the Willard in south-central Brown County.
|Section through the lower part of the Tarkio Limestone Member of the Zeandale Limestone and the upper part of the Willard Shale exposed in the bank of a creek in NW SW sec. 21, T 4 S, R 17 E.||Thickness,
|Tarkio Limestone Member|
|Limestone, light-yellow or tannish-brown, hard, dense; fossil fragments||3.3|
|Shale, tannish-brown to grayish-brown||0.3|
|Sandstone, fine, tannish-brown, soft||5.1|
|Shale, tannish-brown, very sandy and micaceous||15.6|
The Zeandale Limestone consists of three members which, in ascending order, are the Tarkio Limestone, Wamego Shale, and the Maple Hill Limestone members (Pl. 1). The thickness of the Zeandale ranges from 16 to 20 feet, and is best exposed in south-central Brown County.
|Section of Zeandale Limestone measured by R. C. Moore in the spillway of Mission Lake near the C sec. 28, T 4 S, R 16 E.||Thickness,
|Shale, yellowish-brown and bluish-gray; contains carbonaceous streaks, very sandy, micaceous upper part locally grades into yellowish-brown massive sandstone||14.0|
|Sandstone, yellowish-brown, medium- to fine-grained, Soft, massive, cross-bedded and lenticular||3.0|
|Shale, light bluish-gray with brown streaks, calcareous, micaceous and sandy||5.5|
|Maple Hill Limestone Member|
|Limestone, light bluish-gray, weathers light greenish-brown, earthy, massive, breaks into small chips, lower part dark-blue, very hard, dense, fossiliferous||1.2|
|Wamego Shale Member|
|Shale, light-blue, weathers brown, thinly laminated; lower part contains ironstone concretions 1 inch thick, 8 inches in diameter||10.0|
|Tarkio Limestone Member|
|Limestone, light greenish-gray to brown, soft, shaly, grades to calcareous shale, forms slight projection||1.1|
|Shale, light-blue to purple, clayey, hard, blocky||0.3|
|Limestone, light creamy-buff to brown, weathers to rich (lark brown on faces, very massive, hard; contains crinoids, abundant robust fusulinids, breaks into large angular blocks||4.0|
|Shale, light-blue, calcareous, blocky, upper 0.5 foot contains numerous Chonetes, Enteletes, Derbyia, Productus, and Echinoconchus||2.0|
|Sandstone, blue to bluish-gray, lower part thin-bedded to shaly, cross-bedded; contains dark carbonaceous streaks, grades locally into massive sandstone both laterally and vertically, upper part thin-bedded, ripple marked, and micaceous, weathers brown||4.5|
The Tarkio Limestone Member is a hard, grayish-brown to tannish-brown limestone containing crinoids, large fusulinids, and a few brachiopods. It is massive and breaks down into large, angular blocks. Locally, an upper bed of yellowish-brown earthy limestone about 1 foot thick is present. The Tarkio weathers to a rich brown color. The thickness of the Tarkio is about 5 feet. The Member yields no water to wells in the county.
The Wamego Shale Member is a light bluish-gray shale which weathers tannish-brown. Locally a zone of ironstone concretions occurs near the base of the Wamego, and locally a thin coal or carbonaceous zone is present just below the Maple Hill Limestone Member. The Wamego ranges in thickness from 10 to 14 feet. It yields no water to wells in the area.
The Maple Hill Limestone Member is a hard, gray to tannish-gray, earthy limestone which weathers to a tannish-brown color. The Maple Hill breaks along joints into large slabs which, upon further weathering, break into small chips and plates. Locally, the lower part of the Maple Hill is a very hard, dense, dark-blue limestone. The unit is very fossiliferous and ranges from 1 foot to 1.5 feet in thickness. The Maple Hill yields no water to wells in the area.
The Pillsbury Shale consists of beds of gray to grayish-green, sandy, micaceous shale interbedded with sandstone. The sandstone is massive to thin bedded locally and is generally soft, often breaking down into almost loose sand. The sandstone is locally cross-bedded and is ripple marked in the upper part. Shale is more prominent in the lower part of the Pillsbury, and a thin coal occurs locally near the top. Its thickness ranges from about 15 to 25 feet in Brown County. Wells yield small quantities of water from the sandstone beds.
The Stotler Limestone is composed of three members which, in ascending order, are: the Dover Limestone, Dry Shale, and Grandhaven Limestone. In Brown County the Grandhaven Member was not observed and may not be present; however, it does occur in nearby areas.
The Dover Limestone Member is a hard, gray to tannish-gray limestone that weathers brown. It contains large fusulinids, algae, and a brachiopod fauna. The fossils and color of the Dover closely resemble those of the Tarkio Limestone Member of the Zeandale Limestone, but the two differ in weathering characteristics. The Tarkio breaks into large angular blocks upon weathering, whereas the Dover breaks into nodules or chips. The thickness of the Dover is about 5 feet. It yields no water to wells in the area.
The Dry Shale Member is composed of clayey, calcareous gray shale that locally contains beds of sandy shale and possibly some sandstone. The Dry Shale Member thins toward the northern part of the State, and it may be absent in local areas in Brown County. Where the Grandhaven Limestone Member is absent, the Dry Shale Member and the overlying Friedrich Shale Member of the Root Shale cannot be differentiated. The Dry Shale Member attains a maximum thickness of about 8 feet in the county. Some water is produced from sandstone at about the position of the Dry Shale Member; however, the sandstone may be in the lower part of the Friedrich instead of the Dry Shale Member.
The Grandhaven Limestone Member does not crop out in Brown County. Exposures in adjoining areas show that the Member consists of a bed of tannish-brown to brown limestone that weathers blocky to shaly. It is sandy, conglomeratic, and fossiliferous. It is about 2 feet thick.
The Root Shale consists of three members which, in ascending order, are: the Friedrich Shale, Jim Creek Limestone, and French Creek Shale members. The Root Shale occupies a part of the slope between the bench-forming Brownville Limestone Member of the Wood Siding Formation and the Dover Limestone Member of the Stotler Limestone. The intervening limestones do not form a bench, and separation of the strata is difficult. The Root Shale is poorly exposed in Brown County, the best exposures occurring in vertical stream banks and a few roadside ditches. It ranges in thickness from about 45 to 50 feet.
The Friedrich Shale Member is a tannish-gray to bluish-gray calcareous clay shale in places containing a thin coal near the top. Locally, dark-gray lenses of shale occur throughout the Member, sandstone is present in the lower and middle parts, and a bed of fossiliferous shale occurs near the top. The Friedrich Shale Member is about 25 feet thick in Brown County. In the northern part of the State where the Grandhaven Limestone Member of the Stotler Limestone is missing, the Friedrich is difficult to separate from the underlying Dry Shale Member. Small quantities of water are available to wells from the sandstone in the Friedrich.
The Jim Creek Limestone Member is a hard, gray to bluish-gray limestone that breaks into small shaly-appearing chips upon weathering. The Jim Creek is very fossiliferous, and the fauna includes brachiopods and small fusulinids. The Jim Creek ranges in thickness from 0.5 to 1 foot in Brown County and yields no water to wells.
The French Creek Shale Member is a gray to grayish-green clayey, noncalcareous shale, locally sandy in the middle part. The Lorton coal (Schoewe, 1946) is generally present in the uppermost part of the French Creek, and another thin coal or, locally, a carbonaceous zone, occurs a few feet below the Lorton coal. A bed of fossiliferous shale occurs at the top of the French Creek. In places this bed is composed chiefly of Derbyia. The French Creek is about 20 feet thick. Small yields of water are available to wells from the sandy zones in the French Creek.
|Section from upper part of Friedrich Shale Member of the Root Shale through the Brownville Limestone Member of the Wood Siding Formation measured by W. H. Schoewe in NE sec. 34, T 4 S, R 16 E.||Thickness,
|Wood Siding Formation|
|Brownville Limestone Member|
|Limestone, yellowish-brown, granular; contains crystalline calcite, weathers brown, platy base grades irregularly into shale below; contains abundant fossils||2.0|
|Pony Creek Shale Member|
|Shale, limy, micaceous and sandy; contains brachiopods; contains a thin, hard, blue limestone in the lower part (Grayhorse? Limestone Member)||9.0|
|Plumb Shale Member|
|Shale, sandy, red and gray||5.0|
|Nebraska City Limestone Member|
|Limestone, massive, very fossiliferous; contains large Productus, crinoid, bryozoans, Chonetes, weathers light gray||1.6|
|French Creek Shale Member|
|Limy shale, made up largely of Derbyia||1.0|
|Shale, gray, sandy, laminated, pyritic concretions at base, thin beds of black shale||15.65|
|Jim Creek Limestone Member|
|Limestone, bluish-gray, fossiliferous, grades into unit below||0.35|
|Shale, dark-gray; contains thin plates of very fossiliferous limestone||1.0|
|Friedrich Shale Member|
|Shale, clayey, gray||6.0|
Wood Siding Formation
The Wood Siding Formation is composed of five members which, in ascending order, are: the Nebraska City Limestone, the Plumb Shale, the Grayhorse Limestone, the Pony Creek Shale, and the Brownville Limestone. The Formation is best exposed in the southern part of Brown County in the valleys of Delaware River and its tributaries. The thickness of the Wood Siding ranges from about 17 to 20 feet. A measured section through the Wood Siding and the upper part of the Root Shale is given above.
The Nebraska City Limestone Member is a thin, but persistent, dark-gray limestone that weathers light gray. This Member is commonly about 1.5 feet thick and contains an abundant brachiopod fauna. No water is obtained from the Nebraska City in Brown County.
The Plumb Shale Member is a Clayey, calcareous, gray shale which locally contains some red shale. In some places the lower part of the Plumb is sandy and micaceous. In Brown County the Member is about 4 feet thick. It yields no water to wells in the area.
The Grayhorse Limestone Member is a hard, gray to bluish-gray limestone which is locally very fossiliferous. It is commonly less than 1 foot thick. The Member is locally absent or consists of a very thin limestone or limy zone. It yields no water to wells in Brown County.
The Pony Creek Shale Member is a silty, gray shale that contains sandstone in the lower part. The uppermost bed of the Pony Creek is a very fossiliferous gray shale which contains Chonetes and Marginifera. This fauna is similar to that of the overlying Brownville Limestone Member. The Pony Creek ranges in thickness in the county from about 8 to 10 feet. Small supplies of water are available to wells from the sandstone beds in the Pony Creek.
The Brownville Limestone Member is a tannish-gray limestone which weathers brown. The limestone is commonly massive but weathers blocky to platy. The Brownville is abundantly fossiliferous, containing Chonetes, Marginifera, crinoids, and bryozoans. The Member is about 2 feet thick in Brown County and yields no water to wells in the area.
Permian System--Lower Permian Series
Rocks of the Lower Permian Series are divided into three groups in Kansas. These are, in ascending order: the Admire Group, Council Grove Group, and the Chase Group. Only rocks of the Admire and Council Grove groups crop out in Brown County.
The Admire Group consists chiefly of clastic deposits but contains thin limestone beds. Shale predominates in this sequence of rocks, and, because there are few scarp-forming or resistant rocks present, the unit is poorly exposed throughout most of the county. Admire rocks occupy the long slope between the resistant rocks of the overlying Council Grove Group and resistant beds which occur well down into the Wabaunsee Group of Pennsylvanian age. The Admire Group consists of three formations with a thickness of about 110 feet in the county.
The Onaga Shale is the lowermost formation of the Admire Group and consists of three members which are, in ascending order: the Towle Shale, the Aspinwall Limestone, and the Hawxby Shale members. The thickness of the Onaga in Brown County is about 36 feet.
|Measured section of strata from Five Point Limestone Member of the Janesville Shale through Brownville Limestone Member of the Wood Siding Formation exposed in road ditch along west side of sections 15 and 22, T 2 S, R 16 E.||Thickness,
|Five Point Limestone Member|
|Limestone, dark-gray, weathers light gray and slabby; contains fossil fragments||1.8|
|West Branch Shale Member|
|Shale, light-gray to bluish-gray, well-bedded to blocky and clayey; contains a thin, flaggy to nodular impure limestone about 10 feet above base||27.0|
|Falls City Limestone|
|Limestone, dark-brown, tannish-brown with dark reddish-brown spots on fresh break; a porous coquina of pelecypod shells||3.0|
|Hawxby Shale Member|
|Shale, bluish-gray, blocky to platy||10.4|
|Aspinwall Limestone Member|
|Limestone, impure, weathers white, discontinuous||0.6|
|Towle Shale Member|
|Shale, bluish-gray and tannish-gray; contains very dark-gray shale in middle part||25.5|
|Wood Siding Formation|
|Brownsville Limestone Member|
|Limestone, dark grayish-brown, two beds separated by thin shale parting, lower bed contains many Chonetes, other brachiopods, and crinoids||1.5|
The Towle Shale Member is a clayey, noncalcareous tannish-gray to gray shale. Dark-gray shale and maroon shale occur locally in the lower and middle part, and locally, a channel sandstone is present. The Towle is about 25 feet thick in Brown County, and, although no wells are known to obtain water from the Member, small quantities of water should be available from the channel sandstone.
The Aspinwall Limestone Member is a medium-hard, gray to tannish-gray limestone that weathers white. This Member, although commonly about 1 foot thick, is variable in thickness and may be locally absent. The Aspinwall yields no water to wells in the county.
The Hawxby Shale Member is a silty, calcareous, tannish-gray to gray shale. Dark-gray shale occurs locally in the middle part of the unit, which is about 10 to 12 feet thick in Brown County. The Hawxby is poorly exposed in the county where it underlies the steep, grassy slope below the Falls City Limestone. The Hawxby Shale Member yields no water to wells.
Falls City Limestone
The Falls City Limestone is composed of two limestone beds separated by a shale bed. The upper limestone bed is a coquina of pelecypod shells which give the rock a porous or granular appearance (when struck with a hammer, the limestone has a hollow sound). This limestone is commonly about 2-feet thick; however, in the NE cor. sec. 7, T 4 S, R 16 E and NW cor. sec. 8, T 4 S, R 16 E, it thins to about 3 inches in thickness but retains its normal lithologic and textural appearance. This bed generally forms a bench on the slopes and is an excellent marker bed in this area. The upper limestone bed of the Falls City appears to be an excellent water reservoir, and seeps occur in local areas just below the Falls City, but no wells are known to obtain water from this bed. The lower limestone bed is composed of impure, shaly limestone and is probably discontinuous, as it cannot be distinguished in most outcrops of this section of rocks. The shale separating the two limestone beds is a clayey, tannish-gray, noncalcareous shale where it can be identified and is generally about 3 feet thick.
The Janesville Shale consists of two shale members and one limestone member, having a total thickness of about 70 feet in Brown County. The members of the Janesville are, in ascending order: the West Branch Shale, the Five Point Limestone, and the Hamlin Shale.
The West Branch Shale Member is composed of about 27 feet of gray, grayish-green, and tan shale. This shale is silty, calcareous, and locally contains thin zones of impure limestone. The West Branch does not yield water to wells in the county.
The Five Point Limestone Member is composed of two limestone beds and an intervening shale bed that varies in thickness within relatively short distances. The upper limestone bed is generally a hard, dense, gray limestone containing many fossils, but locally it may be an earthy, rubbly, fossiliferous limestone. The shale bed is a drab, grayish-brown, clay shale which varies in thickness from less than 1 foot to about 4 feet. The lower limestone is a gray, dense, hard limestone which weathers platy, the individual plates being about 0.5-inch thick. This lower limestone generally is unfossiliferous and uniform in appearance and weathering characteristics, but locally, it is a dense, gray limestone containing small gastropods in the lower part and a brachiopod fauna in the upper part. Here the limestone becomes nodular upon weathering. The Five Point is as much as 5 feet thick in local areas but is commonly 3 feet thick or less. No wells obtain water from it in Brown County.
The Hamlin Shale Member is about 40 feet thick in Brown County. The Hamlin is composed principally of gray and tannish-gray calcareous, clay shale, but locally, the upper few feet may contain black or dark-gray fissile shale. Sandstone and sandy shale are present in the middle and lower parts. Locally in Brown County, celestite (SrSO4) occurs in veins or joint fillings in the shale just below the zone containing the dark shale. This zone is about 10 feet thick and, according to Fishburn and Davis (1962), the celestite was a product of chemical precipitation brought about by stagnation of a local area in the Permian sea and concentrated in the joint-controlled veins by circulating ground water. Below the celestite zone, sandstone, sandy shale, and gray and tan clay shale are present to the top of the Five Point Limestone Member. Some water is available to wells from the sandy shale and sandstone in the Hamlin, but yields are small.
|Section of part of Foraker Limestone and Hamlin Shale Member of the Janesville Shale exposed in road cuts west from NE NW NE sec. 7, T 3 S, R 16 E.||Thickness,
|Council Grove Group|
|Hughes Creek Shale Member|
|Shale, sandy, tannish-gray and light-gray; contains a brachiopod fauna||3.0|
|Limestone, dark-gray, weathers tannish-gray; contains fusulinids||1.0|
|Shale, gray, fossiliferous||2.2|
|Limestone, hard, dark-gray, weathers tannish-gray; contains fusulinids||1.0|
|Shale, gray and light-gray||5.6|
|Limestone, impure, buff, upper 4 inches hard, contains a mixed brachiopod fauna and fusulinids in lower part||1.2|
|Shale, gray and tannish-gray||6.8|
|Limestone, impure, nodular; contains Productus and spiriferid brachiopods||1.2|
|Shale, light-gray, sandy in part; contains thin sandy siltstone partings||5.8|
|Shale, dark-gray, platy||5.0|
|Americus Limestone Member|
|Limestone, gray, crinoidal bed, hard||0.9|
|Limestone, gray, impure, massive to nodular||1.0|
|Hamlin Shale Member|
|Shale, light-gray, very limy||1.0|
|Shale, light tannish-gray||3.2|
|Shale, gray; contains celestite in joint fillings||10.4|
|Shale, gray, sandy||6.2|
|Shale, gray; contains calcareous pellets||4.5|
|Sandstone, massive, micaceous, well-cemented||2.0|
|Shale, tannish-gray, very sandy||6.0|
Council Grove Group
The Council Grove Group, according to the Kansas classification, is composed of seven limestone and seven shale formations. Six of the limestones and five of the shales crop out in Brown County, comprising a thickness of about 220 feet of strata.
Rocks of the Council Grove are considerably different from those of the Admire and Wabaunsee groups. The limestone units of the Council Grove are generally thicker than those of the other groups, and many contain appreciable amounts of chert which is scarce in the older rocks. The Council Grove limestones are generally lighter in color and lack the brown color upon weathering of the Admire and Wabaunsee limestones. The shale in the Council Grove is variegated in color and contains more lime and is more fossiliferous than the older rocks. Coal and sandstone are rare in occurrence in comparison with the older rocks.
The Foraker Limestone consists of three members which are, in ascending order: the Americus Limestone, the Hughes Creek Shale, and the Long Creek Limestone. The total thickness of the Foraker Limestone is about 40 feet.
The Americus Limestone Member consists of two limestone beds separated by an intervening shale bed. The upper bed is a hard, gray to bluish-gray limestone containing crinoids, brachiopods, and bryozoans. It ranges in thickness from about 0.7 to 1.0 foot and maintains a rather uniform appearance and thickness in the county. The lower limestone, which is about 1 foot thick, is quite variable in lithology in the county. Locally this bed may be a pelletal limestone containing fossil fragments, or it may be a dense, hard limestone resembling the upper bed. In other exposures, the lower bed is shaly and grades into the underlying shale, which is the top of the Admire Group. The shale bed between the two limestone beds is tannish-gray to gray and in most exposures contains a thin, black zone near the middle. It is calcareous and unfossiliferous and ranges in thickness from about 1 foot to 3.5 feet but commonly is about 1.5 feet in thickness. The Americus yields no water to wells in the area.
The Hughes Creek Shale Member is a silty, calcareous, gray to tannish-gray shale and generally contains some dark-gray shale in the lower part. Several thin beds of limestone occur in this Member. The Hughes Creek is fossiliferous throughout; fusulinids are especially common in the thicker limestone bed. The Hughes Creek is about 32 feet thick in the county and does not yield water to wells in the area.
The Long Creek Limestone Member is a soft, massive, gray to tannish-gray, slightly dolomitic limestone. It is locally porous and cavernous. The Long Creek ranges in thickness from 6 to 8 feet in Brown County but is poorly exposed because it is less resistant to weathering than the underlying limestone. It weathers back from the bench formed by these limestones and is generally mantled by colluvial material. Water is available to wells from the porous limestone in the Long Creek, but it is generally high in sulfates. The sulfate concentration increases with depth.
The Johnson Shale is a silty, calcareous and platy, dark-gray shale in the upper part and a gray, blocky, calcareous shale in the lower part. The lowermost part is fossiliferous containing a mixed fauna of brachiopods, crinoids, and bryozoans. The Johnson Shale averages about 20 feet in thickness in most of its outcrop area in Kansas, but in Brown County the Johnson ranges from 5 to 7 feet in thickness. The Johnson Shale yields no water to wells in the county.
Red Eagle Limestone
The Red Eagle Limestone is about 5.5 feet thick n Brown County and consists of three members which, in ascending order, are: the Glenrock Limestone, the Bennett Shale, and the Howe Limestone.
|Section from lower part of Grenola Limestone down to the Johnson Shale. Exposure in a creek bank in NE SE SE sec. 3, T 1 S, R 15 E, measured by C. K. Bayne and S. M. Ball.||Thickness,
|Burr Limestone Member|
|Limestone, bluish-gray, weathers tannish-gray||0.5|
|Legion Shale Member|
|Shale, gray, calcareous, poorly exposed||3.0|
|Sallyards Limestone Member|
|Shale, tannish-gray to gray, sandy||12.0|
|Limestone, earthy, very porous, boxwork structure||4.5|
|Shale, clayey, gray and tannish-gray, limy in middle part of unit||4.2|
|Shale, gray, laminated, platy to massive||13.0|
|Red Eagle Limestone|
|Howe Limestone Member|
|Limestone, single massive bed, gray, fossiliferous||0.9|
|Bennett Shale Member|
|Shale, gray, clayey to silty, flaky to blocky||1.3|
|Shale, black, fissile to platy; contains Orbiculoidea and conodonts||1.7|
|Glenrock Limestone Member|
|Limestone, single massive bed, silty, contains Allorisma and other pelecypods, fusulinids, productids, and bryozoans||1.2|
|Limestone, gray, shaly, weathers rubbly; contains brachiopods and crinoids||0.5|
|Shale, dark-gray, silty, flaky||2.0|
|Limestone, shaly, discontinuous over short distances, contains bellerophontid gastropods||0.0 to 0.9|
|Shale, dark-gray, clayey to silty, platy to flaky||1.5|
|Limestone, gray, nodular to shaly; contains Composita, Chonetes, and crinoids||1.0|
|Shale, dark-gray, papery||1.0|
The Glenrock Limestone Member is about 1.5 feet thick. The upper 1 foot is a hard, massive, gray limestone containing many fossils. The lower 0.5 foot is a gray, silty limestone which weathers flaky and contains a brachiopod fauna and crinoids. The Glenrock yields no water to wells in Brown County.
The Bennett Shale Member is about 3 feet thick in Brown County. The upper part is a gray to dark-gray, calcareous clay shale which weathers flaky. The lower part of the Bennett is a black, fissile shale which contains Orbiculoidea and conodonts. The Bennett yields no water to wells in the area.
The Howe Limestone Member is a soft, silty, gray limestone about 1 foot thick. The unit consists of one massive bed which in the upper part contains fragments of brachiopods and many ostracodes. Locally, the Howe yields small quantities of water to wells.
The Roca Shale is about 34 feet thick in Brown County. The upper part of the Roca is gray to tannish-gray sandy shale. The middle part is composed of very porous limestone having a boxwork structure. Below the porous limestone is a zone of limy shale. The lower part of the Roca is a gray, clayey, massive to flaky shale. The porous limestone in the middle part of the Roca is an important aquifer in northwestern Brown County. Yields up to 150 gpm may be obtained locally from this bed. South of the center of the county the porous limestone thins or is absent, and little or no water is obtained from the Roca.
The Grenola Limestone consists of five members which, in ascending order, are: the Sallyards Limestone, the Legion Shale, the Burr Limestone, the Salem Point Shale, and the Neva Limestone. The thickness of the Grenola in Brown County is about 28 to 30 feet.
The Sallyards Limestone Member is a hard, gray to tannish-gray fossiliferous limestone. The Sallyards generally consists of a single bed which weathers blocky. The Member ranges in thickness from 1 to 1.5 feet in the county and yields no water to wells in the area.
The Legion Shale Member is composed of gray and tannish-gray silty calcareous shale that contains a thin zone of black platy or fissile shale near the top. The Legion ranges in thickness from about 1.5 to 3 feet in the county. No water is obtained from the Legion in the area.
The Burr Limestone Member is poorly exposed in Brown County. Generally the Member is covered by colluvium and slump from the overlying beds. In adjacent areas the Burr consists of two or more beds of limestone separated by beds of shale. In Brown County only the lowermost limestone bed and an overlying shale were observed. This limestone bed is a hard, gray, fossiliferous limestone about 1 foot thick which weathers into small tannish-gray chips. The Burr yields no water to wells.
The Salem Point Shale Member is a silty, calcareous, greenish-gray to tannish-gray shale, which in Brown County ranges in thickness from about 4 to 8 feet. The Member is poorly exposed and does not yield water.
The Neva Limestone Member is about 13 feet thick in Brown County and consists of alternating beds of limestone and shale. Most of the limestone beds in the Neva are massive, somewhat porous, and fossiliferous. The uppermost bed of limestone is about 6 feet thick and consists of an upper soft, shaly, tannish-gray limestone underlain by a massive brownish-gray limestone about 4 feet thick. The limestones below the uppermost bed are gray. The shale beds are gray and tannish-gray and are silty, calcareous, and thin-bedded. A black fissile shale occurs in the lower part of the Neva in this area. The Neva Limestone Member yields small to moderate quantities of water to wells in western Brown County.
|Section from the Morrill Limestone Member of the Beattie Limestone through the Neva Limestone Member of the Grenola Limestone in SE sec. 19, T 1 S, R 15 E, measured by R. C. Moore.||Thickness,
|Morrill Limestone Member|
|Limestone, gray, weathers granular, hard, dense, fossiliferous; lower part light blue, weathers bluish-gray, fine-textured, earthy; contains an abundant molluscan fauna||0.9|
|Limestone, white, soft, shaly||1.3|
|Florena Shale Member|
|Shale, light-gray, very calcareous and fossiliferous||3.0|
|Cottonwood Limestone Member|
|Limestone, white, soft, chalky, massive, weathers shelly; contains many fusulinids||5.5|
|Shale, greenish-gray, calcareous, partly covered||28.0|
|Neva Limestone Member|
|Limestone, light tannish-gray, lower part single massive bed 4 feet thick, upper part soft, somewhat shaly||6.0|
|Shale, calcareous, grayish-brown||1.3|
|Limestone, gray, impure, earthy, massive||1.4|
|Shale, greenish-gray, calcareous||0.8|
|Limestone, light- and dark-gray, impure, weathers blocky, very fossiliferous||0.4|
|Shale, soft, black, fissile||3.0|
|Shale, light- and dark-gray, hard, calcareous, grades to soft shaly limestone; contains Orbiculoidea and other brachiopods||0.9|
|Limestone, hard, dense, massive, light-gray||1.2|
|Salem Point Shale Member|
|Shale, gray to tannish-gray, blocky||8.0|
The Eskridge Shale is composed of varicolored shale with gray and tannish-gray being the dominant colors. Several persistent thin beds of limestone, generally less than 1 foot thick, occur in the Eskridge. The thickness in Brown County is about 30 feet. The Eskridge occupies the slope between the Grenola Limestone and the Beattie Limestone and is generally poorly exposed. Partial exposures are best seen in road ditches and stream banks. Coal occurs in the upper part of the Eskridge in Brown County (Moore, et al., 1951). This coal is thin and discontinuous and not of commercial quality. The Eskridge yields no water to wells in the county.
The Beattie Limestone consists of three members which, in ascending order, are: the Cottonwood Limestone, the Florena Shale, and the Morrill Limestone. The Beattie is about 12 feet thick in Brown County.
The Cottonwood Limestone Member is a light-gray to white, massive limestone. The Member is best exposed in northwestern Brown County where it is about 5.5 feet thick. The Cottonwood in northern Kansas is not as hard as it is in the central part of Kansas and does not form the conspicuous bench strewn with large blocks of limestone so characteristic of the Member in the central part of the State. In Brown County the Cottonwood contains abundant fusulinids and scattered chert nodules. Solution channels are present in the Member and, in some localities small quantities of water are obtained from it.
The Florena Shale Member is a silty, very calcareous, light-gray to tannish-gray shale. The Florena is very fossiliferous, containing a mixed fauna in which Chonetes is especially abundant. The Florena is about 3 feet thick in northwestern Brown County but thickens to about 6 feet in the west-central part. The Florena yields no water to wells in the area.
The Morrill Limestone Member consists of two limestone beds separated by a shale bed. The upper limestone bed is a hard, dense, gray limestone containing brachiopods, and, upon weathering, the limestone has a granular appearance. The lower limestone bed is soft and weathers shaly. The intervening shale is gray to grayish-green. The Morrill is about 3 feet thick in Brown County and yields no water to wells in the area.
The Stearns Shale is poorly exposed in Brown County where it occupies the slope between the small benches formed by the Beattie Limestone and the Bader Limestone. The Stearns is about 15 feet thick in the county and is composed of gray and tannish-gray silty calcareous shale grading downward to gray-green shale. It commonly contains a thin limestone near the top. The Stearns yields no water to wells in the area.
The Bader Limestone consists of three members which, in ascending order, are the Eiss Limestone, the Hooser Shale, and the Middleburg Limestone members. The Bader is about 25 feet thick in the county.
|Section from Crouse Limestone through the Bader Limestone in SE NE SW sec. 25, T 1 S, R 14 E, measured by M. R. Mudge (slightly modified by Bayne).||Thickness,
|Till, clayey, noncalcareous, brown, numerous small erratics||5±|
|Limestone, medium hard, tan to tannish-brown, massive, weathers tan and blocky||1.7|
|Limestone, medium hard, tan, thin-bedded; weathers shaly; fossiliferous||1.1|
|Shale, clayey, calcareous, tannish-gray, weathers tan and blocky; contains calcareous nodules||7.1|
|Limestone, medium hard, gray; weathers tan and blocky, cavernous, fossiliferous||1.3|
|Easly Creek Shale|
|Shale, silty, calcareous, thin-bedded to blocky, light-gray to grayish-green, mottled with maroon in middle part, calcareous lenses in middle part and calcareous nodules in upper part||2.8|
|Shale, silty, calcareous, mostly blocky; some thin-bedded, alternating between gray, grayish-green and maroon||2.9|
|Shale, silty, calcareous, mostly thin-bedded, some blocky, inter-bedded gray, grayish-green and maroon beds somewhat thicker than overlying beds||7.2|
|Shale, clayey, calcareous, grayish-green; weathers tan, thin-bedded, numerous calcareous lenses which weather cavernous||2.9|
|Middleburg Limestone Member|
|Limestone, hard, tannish-gray; weathers tan and blocky; cavernous and porous in upper part; many fossil fragments in upper part which weather faster than matrix and give the surface a porous appearance||1.1|
|Limestone, soft, tannish-gray; weathers tan and blocky to shaly in lower part||0.7|
|Limestone, hard, gray, massive; weathers tannish-gray; blocky near top and shaly in lower part; contains numerous high-spired gastropods in lower part; fossil fragments common throughout||2.0|
|Hooser Shale Member|
|Shale, silty, calcareous, tannish-gray, thin-bedded; weathers tan and blocky||1.6|
|Limestone, bard, dense, weathers light-gray||0.1|
|Shale, silty, calcareous, thin-bedded to blocky, grayish-green in upper part and tannish-gray in lower part; contains calcareous lenses in lower part||3.1|
|Shale, silty, calcareous, thin-bedded, maroon with grayish-green lenses; calcareous nodules at base||3.1|
|Shale, silty, calcareous, maroon||0.6|
|Shale, silty, calcareous, grayish-green||0.6|
|Limestone, hard, clayey, gray||0.2|
|Shale, silty, calcareous, tannish-gray||0.3|
|Shale, clayey, noncalcareous, grayish-green||0.2|
|Eiss Limestone Member|
|Limestone, soft, dolomitic, massive, tan, irregularly porous||2.9|
|Shale, silty and clayey, calcareous, tannish-gray; weathers tan, blocky||5.6|
|Limestone, medium hard, gray to light-gray, massive; weathers light-gray and shaly; abundant high-spired gastropods in lower part, very fossiliferous||1.6|
|Shale, silty to calcareous, thin-bedded to blocky, gray to grayish-green; lower part weathers cavernous||5.3|
The Eiss Limestone Member consists of two or more limestone beds separated by shale. The uppermost bed of limestone is dolomitic and generally massive and soft. The shale bed is silty, calcareous, and tannish gray. The lower bed of limestone is about 1 foot thick and is a gray silty to shaly, very fossiliferous limestone. A type of high-spired gastropod is especially abundant in the lower part. The Eiss is about 10 feet thick in Brown County and yields no water to wells in the area.
The Hooser Shale Member is a silty, calcareous shale. The unit is varicolored with grayish green and tannish gray dominant. One or more thin beds of limestone occur in the Hooser in Brown County. The Hooser is about 11 feet thick and yields no water to wells in the area.
The Middleburg Limestone Member is about 4 feet thick in Brown County and is composed of one or more beds of limestone, locally separated by a thin bed of shale. The limestone is medium hard and light-gray and weathers tannish gray. The uppermost limestone bed is porous. The lower bed of limestone is hard, massive, and very fossiliferous. A type of small high-spired gastropod is especially abundant in this bed. The Middleburg yields no water to wells in Brown County.
Easly Creek Shale
The Easly Creek Shale is a silty, calcareous, varicolored shale. Gray and grayish green are the dominant colors; however, maroon shale occurs throughout the section, and tan shale is present in the lower part. Thin, limy zones occur in the middle and lower parts. The Easly Creek is not fossiliferous in Brown County. It ranges in thickness from 16 to 19 feet and does not yield water to wells.
The Crouse Limestone is the uppermost rock of Permian age which crops out in Brown County. The Crouse consists of two limestone beds separated by a relatively thick bed of shale. The lower limestone bed is a hard, dense, massive, gray limestone about 1 foot thick and is fossiliferous throughout. The shale bed is clayey, calcareous, and tannish-gray. It is somewhat platy at the top and blocky in the lower part. This shale is about 6 feet thick. The upper limestone bed is about 3 feet thick and is a tannish-gray, earthy limestone which weathers porous. The Crouse yields no water to wells in Brown County.
Quaternary System--Pleistocene Series
The Pleistocene Epoch is the last of the major divisions of geologic time and has been called the "Ice Age" owing to the presence of continental glaciers in North America and elsewhere. The Pleistocene Series in Kansas has been divided into the Nebraskan, Kansan, Illinoisan, and Wisconsinan glacial stages and the Aftonian, Yarmouthian, Sangamonian, and Recent interglacial stages. Events in each of the periods of continental glaciation followed a cyclic repetition. Each cycle consists of a glacial and an interglacial stage. The cycle in a marginal belt around a glaciated area and ahead of an advancing glacier is characterized by a period of down-cutting in the valleys with some local deposition of sediments followed by a period of deposition of coarse material. Progressively finer heterogeneous material is deposited on the melting ice as the glacier retreats, and finally development of a soil profile occurs during the interglacial stages over a large area where surface conditions are relatively stable.
During the Nebraskan and Kansan stages, continental glaciers covered part of northeastern Kansas. The Kansan glacier covered all of Brown County, and deposits of this age occur in the county. The Nebraskan glacier probably entered the county, but no glacial deposits associated with this stage of glaciation were identified. Non-glacial Pleistocene deposits of pre-Kansan age are present in the county. The thickness of the Pleistocene rocks and their relation to the underlying Pennsylvanian and Permian rocks are shown on the cross sections on Plate 2.
Nebraskan and Aftonian Stages
Deposits of chert gravel containing some locally derived limestone gravel crop out in northwestern Brown County. Local deposits of similar lithology crop out and are found in test holes beneath glacial drift of Kansan age in eastern Brown County. Both of these deposits, because they occur below the drift and apparently do not contain glacial material, are considered to be of Nebraskan and Aftonian ages (Pl. 1). North and northwest of Morrill, numerous deposits of chert gravel occur in the highest topographic position, and in northeast Brown County similar gravel is present below lacustrine deposits in a deep channel. The deposits are generally less than 10 feet thick, and in northwest Brown County they lie above the water table and yield no water to wells. The gravel in the channel area in northeastern Brown County is as much as 20 feet thick. These deposits are saturated, and yields up to 100 gpm may be available in local areas although they are not utilized at present.
Kansan and Yarmouthian Stages
Several deposits associated with the glacier that covered Brown County during the Kansan Stage were identified during this study. These are glaciolacustrine deposits assigned to the Atchison Formation, glacial till or sediments laid down directly by the melting ice, and outwash deposits, or deposits laid down by meltwater flowing from the ice. These outwash deposits are in part equivalent to the Grand Island Formation.
Glaciolacustrine deposits composed of silt and very fine sand were present in several test holes in northeast Brown County. No outcrops of these deposits were observed in the county during the study, but in adjacent Atchison and Nemaha counties, similar deposits crop out. In these areas the deposits display bedding and staining by limonite on the bedding planes. In Atchison County these deposits have been named the Atchison Formation (Frye and Leonard, 1952). In Brown County the Atchison occurs near the base of a buried channel in the northeast part of the county (Pl. 2) and are overlain by glacial till or outwash material. It is believed that these deposits were laid down in relatively quiet water such as in a lake formed when the advancing ice blocked an old drainage way. Locally in this part of the county, the Atchison is underlain by a gravel of local origin which is believed to be of Nebraskan age. The Atchison Formation ranges in thickness from 0 to about 50 feet in Brown County. The Atchison Formation lies below the water table, and small supplies of water could be obtained, but no wells are known to obtain water from this Formation in the county.
Kansas Till and Outwash Deposits
The Kansas Till is a non-stratified glacial deposit consisting principally of clay but containing silt, sand, gravel, cobbles, and boulders deposited by the melting ice. Lenses of sand and gravel may be present at any horizon in the till. The unweathered till ranges from tannish gray to dark gray or bluish gray, and the weathered till is generally tannish brown or brown. The till contains fractures which dip at a steep angle and which have been filled with calcium carbonate and stained by limonite. Boulders are interspersed throughout the till and range widely in concentration over relatively short distances. The maximum thickness of till encountered in test holes in Brown County was about 115 feet.
Outwash deposits consisting of poorly-sorted to moderately-sorted silt, sand, and gravel are present in much of Brown County. This material was deposited by meltwater streams flowing away from the ice front and occurs both under and on top of till. These deposits range in thickness from 0 to about 100 feet. The outwash deposits appear to have been deposited in poorly defined channels which generally are not traceable more than short distances away from the outcrop area. One of the more prominent channels, about 1 mile west of Everest, is a north-south trending channel and may extend north and northwest to an area about 1 mile northeast of the community of Baker where outwash gravel is exposed in gravel pits. The material comprising this deposit is principally quartz sand; however, granitic and metamorphic rocks and boulders are also present. It is moderately well sorted but contains a small amount of silt and fine sand. The city of Everest obtains the municipal water supply from well 5-18-6dbb which was test-pumped at a rate of 250 gpm from these deposits.
In the area adjacent to Walnut Creek in west-central and northern Brown County and adjacent to Wolf River in east-central Brown County, numerous outcrops of outwash occur. An outwash deposit in SW NE sec. 32, T 2 S, R 16 E is exposed in a pit in a terrace adjacent to Walnut Creek. In this pit quartz sand is the most common material, but pebbles derived from glacial till and locally-derived material are also present. A molluscan fauna from the silt in this pit indicates a late Kansan age. All the outwash deposits except the chert gravel deposits of pre-Kansan age and the glaciolacustrine deposits of the Atchison Formation are considered in this report to be a part of the Grand Island Formation, although some are laid down directly on till and some occur in terrace position and may be somewhat younger.
Little water is ordinarily available to wells from the till, although in local areas, sand and gravel lenses incorporated in the till yield small quantities of water. The outwash deposits comprise the most important and widespread aquifer in Brown County. Yields ranging from a few gallons per minute to as much as 450 gpm are obtained. The major streams in the county have entrenched their valleys below the drift deposits in most of the area, and subsequent draining near the stream has made it difficult to obtain dependable water supplies from the drift in these areas. The changes in lithology and sorting which occur in glacial drift make it difficult to predict the availability of water from the drift; however, in a drift deposit 20 to 30 feet thick, one can expect one or more lenses of sand or gravel from which yields of several gallons per minute can be expected.
Illinoisan and Sangamonian Stages
Following the retreat of the Kansan glacier, erosion began on the till plain and most of the outwash deposits were laid down. During the Illinoisan Stage, erosion continued in the area, and a great quantity of material was removed (Pl. 2). It is probable that some deposition occurred during the Illinoisan, but quantitatively it was small, and the deposits were either removed during the Wisconsinan Stage or were not recognized in this study. A few discontinuous fluvial deposits in terrace position along Walnut Creek valley in north-central Brown County may be Illinoisan in age, but they are small in areal extent and are not shown on Plate 1.
In many local areas the upper surface of drift below the Wisconsinan loess is weathered. Part of this weathering could have occurred during Yarmouthian time when conditions were relatively stable, but it is believed that a soil formed during this period would have been largely removed by erosion during Illinoisan time and that the weathering is principally of Sangamonian age. Some loess and alluvial deposits of Illinoisan and Sangamonian age may be present in the county, but, with the exception of the fluvial deposits in Walnut Creek valley, they are not recognized. These deposits yield no water to wells in the area.
Wisconsinan and Recent Stages
During the early Wisconsinan time, many of the older deposits were eroded. The present stream system was established, and the streams entrenched their valleys to about their present level. This early eroding phase was followed by a period during which the valleys were partly filled with alluvial material, and loess derived from the valley trains from the Wisconsinan glaciers to the north was deposited in the uplands and on the valley walls.
The loess deposits (Pl. 1) may contain some loess of Illinoisan age, but are principally composed of early Wisconsinan loess (Peoria Formation) and late Wisconsinan loess (Bignell Formation). The Bignell and the Peoria loess can only be differentiated in this area through their contained molluscan fauna or, locally, by a zone which is leached of calcium carbonate at the top of the Peoria Formation. The maximum observed thickness of loess in Brown County was 86 feet. The loess is thickest in the northeast part of the county near the Missouri River and thins toward the west and southwest (Pl. 2). The loess is not an aquifer in the area.
The Wisconsinan and Recent alluvial deposits (Pl. 1) are composed of clay, silt, sand, and gravel. These deposits are generally poorly sorted, and relatively small supplies of water are obtained from them. The thickness of the Wisconsinan and Recent alluvial deposits ranges from only a few feet to about 55 feet.
Kansas Geological Survey, Geology
Placed on web May 29, 2009; originally published May 1967.
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