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Table of Contents

Abstract

Introduction

Geography

Geology

Ground Water

Geologic Formations

Water Levels

Well Records

Logs of Test Holes

References

Plates

Geology

Summary of Stratigraphy

Plate 7A--Thin-bedded Smoky Hill chalk member of the Niobrara formation exposed in SW SE sec. 6, T. 20 S., R. 31 W.

The exposed rocks in Scott County are underlain by older sedimentary rocks of pre-Cambrian age. The stratigraphic sequence of the rocks underlying the surface is fairly well known from the togs and well cuttings of each of the oil tests in the Shallow Water oil pool in south-central Scott County.

Table 1--Generalized section of the geologic formations in Scott County, Kansas.

System	Series	Formation Member		Thickness (feet)	Physical character	Water supply
Quaternary	Pleistocene and Recent	Alluvium		0-20 ±	Gravel, sand, silt and clay comprising stream deposits in Beaver (Ladder) Creek valley.	Yields small supplies of relatively hard water to wells in Beaver (Ladder) Creek valley.
		unconformable on older formations
		Dune sand		0-50 ±	Fine to medium sand. Mantles small areas in the southeastern part of the county. Except where reopened by recent blowouts, the dunes are stabilized by vegetation.	Probably does not supply water directly to wells but is important as a favorable catchment area for ground-water recharge to adjacent and underlying formations.
		unconformable on older formations
		Loess		0-30	Light buff-colored silt containing fine sand and some clay.	Loess deposits occur mostly above the water table and are relatively impermeable.
		unconformable on older formations
	Pleistocene	Undifferentiated deposits, including channel deposits along Beaver (Ladder) Creek		0-200 ±	Predominantly unconsolidated sands and gravels containing silt and clay. Basal channel deposits are cemented in at least one small exposure along Beaver Creek.	Where saturated yield large supplies of moderately hard water to most of the wells in the shallow-water basin. Channel deposits are relatively permeable but generally occur above the water table.
		unconformity
Tertiary	Pliocene	Ogallala formation		0-160	Gravel, sand, silt, caliche, and some silty clay. Contains hard and soft layers of sandstone and conglomerate, much of which is crossbedded and cemented with lime. Lower part locally contains mottled bentonitic clay ranging in color from reddish brown to	Yields moderate to large supplies of moderately hard water to domestic and stock wells in many parts of the county. Constitutes the principal source of supply for many of the irrigation wells in Scott Basin.
		unconformity
Cretaceous	Gulfian*	Niobrara formation	Smoky Hill chalk	0-130 ±	Alternative beds of soft chalk and chalky shale.	Yields limited supplies of hard to very hard water to wells in the southeastern quarter of the country.
			Fort Hays limestone		Massive chalk beds separated by thin, soft, chalky shale.	Not known to yield water to wells in Scott County.
		Carlile shale	Codell sandstone	180-230	Sandstone and sandy shale.	Not known to yield water to wells in Scott County. The Codell sandstone member is reported to yield meager quantities of water to wells in Finney County. The Blue Hill shale and Fairport chalky shale members of the Carlile shale are relatively impermeable
			Blue Hill shale		Bluish-gray clay shale containing septarian concretions in upper part.
			Fairport chalky shale		Yellow chalky shale with thin limestone beds.
		Greenhorn limestone	Pfeifer shale, Jetmore chalk, Hartland shale, Lincoln limestone	0-55	Alternating beds of chalky shale and thin chalky limestones.	Not known to yield water to wells in Scott County.
		Graneros shale		25-100	Dark bluish-gray clay shale containing thin-bedded limestone and sand lenses.	Relatively impermeable; not known to yield water to wells in Scott County.
		Dakota formation		260-550 ±	Sandstones, shales, and clays.	Not known to yield water to wells in Scott County. The sandstones of the Dakota formation yield moderate supplies of soft water to wells in southeastern Gray County and in Ford County. The Kiowa shale is relatively impermeable.
	Comanchean*	Kiowa shale			Black marine shale and a few thin limestone beds.
		Cheyenne sandstone			Fine to coarse-grained sandstone and sandy shale.
		unconformity
Permian	Leonardian and Guadalupian*	Undifferentiated redbeds		1,150 ±

* Classification of the State Geological Survey of Kansas

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