GEOLOGICAL SURVEY CIRCULAR 106

June 1951

GEOLOGIC CONSTRUCTION-MATERIAL 

RESOURCES IN MITCHELL ^COUNTY,

KANSAS

Frank E. Byrne, Wendell B. Johnson, 

and Denzil W. Bergman

PREPARED IN COOPERATION WITH THE 

STATE HIGHWAY COMMISSION OF KANSAS

R. C. Keeling, State Highway Engineer 

S. E. Horner, Chie* Geologist

R. D. Finney, Chief Engineer

Prepared as Part of a Program

of the Department of the Interior

for Development of the Missouri River Basin
UNITED STATES DEPARTMENT OF THE INTERIOR

Oscar L. Chapman, Secretary

GEOLOGICAL SURVEY

W. E. Wrather, Director

Washington, D. C.

Free on application to the Geological Survey, Washington 25, D. C.
CONTENTS

Page

Introduction. .............. l

Purpose of the investigation ..... 1

Geography ............./1

Area covered by the investigation. 1

Topography .......... 1

Drainage. ........... 1

Climate ............ 1

Transportation routes ...... 3

Investigation procedure ....... 3

Acknowledgments .......... 3

Characteristics of the outcropping

stratigraphic units ........... 4

General .............. 4

Dakota sandstone .......... 4

Areal distribution. ....... 4

General description. ...... 4

Representative measured section. @

Thickness ........... 6

Construction materials ..... 6

Graneros shale ........... 6

Areal distribution. ....... 6

General description. ...... 6

Representative measured section. 7

Thickness ........... 7

Construction materials ..... 7

Greenhorn limestone ........ 7

Areal distribution. ....... 7

General description ....... 7

Lincoln limestone member. . 7

Hartland shale member ... 8

Jetmore chalk member ... 8

Pfeifer shale member .... 8

Representative measured sections 9

Thickness ........... 13

Construction materials ..... 13

Carlile shale ............ 13

Areal distribution. ....... 13

General description . ...... 13 '

Fairport chalky shale

member ......... 13

Blue Hill shale member ... 13

Codell sandstone member . . 14 

Representative measured

sections ........... 14

Thickness ........... 14

Construction materials ..... 14

Niobrara formation ......... 14

Areal distribution. ....... 14

General description. ...... 15

Representative measured

section ........... 15

Thickness ........... 15

Construction materials ..... 15

Page

Sanborn formation ......... 15

Areal distribution ....... 15

General description ...... 16

Representative measured section 16 

Thickness ........... 16

Construction materials ..... 16

Terrace deposits. ......... 16

Areal distribution ....... 16

General description ...... 16

Representative measured section 17 

Thickness ........... 17

Construction materials ..... 17

Alluvium ............. 17

Areal distribution ........ 17

General description ...... 17

Representative measured section 17 

Thickness. .......... 17

Construction materials ..... 17

Inventory of construction materials ... 17 

General. ............. 17

Aggregate for concrete ....... 18

Engineering and geologic

characteristics ....... 18

Stratigraphic sources and performance characteristics ... 18 

Sanborn formation ..... 18

Alluvium ......... 18

Road metal ............ 18

Engineering and geologic

characteristics ....... 18

Aggregate for concrete ... 18 

Indurated rocks ...... 18

Limestone gravel ..... 19

Stratigraphic sources and performance characteristics ... 19 

Sources of aggregate for

concrete ........ 19

Indurated rocks ...... 19

Dakota sandstone. ... 19

Greenhorn limestone . . 19 

Carlile shale ..... 19

Niobrara formation. . . 19 

Sanborn formation ..... 19

Mineral filler ........... 19

Engineering and geologic

characteristics ....... 19

Stratigraphic sources and performance characteristics ... 19 

Sanborn formation ..... 19

Terrace deposits. ..... 20

Riprap .............. 20

Engineering and geologic

characteristics ........ 20
CONTENTS 

(Continued)

Inventory of construction mate rials -- 

Continued

R ip r ap - - C ontinue d

Stratigraphic sources and performance characteristics . , Dakota sandstone .....

Greenhorn limestone . . . Niobrara formation ....

Structural stone .........

Engineering and geologic

characteristics. ......

Stratigraphic sources and performance characteristics . , Greenhorn limestone . . , Niobrara formation. . . , 

Calcareous binder ........

Engineering and geologic

characteristics. ......

Page

20

20

20

20

20

20

20

20

20

20

20

Stratigraphic sources and performance characteristics . . 

Greenhorn limestone . . . 

Niobrara formation ....

Subgrade and'embankment

material............

Engineering and geologic

characteristics .......

Stratigraphic sources and performance characteristics . . 

Fine-granular sediments . 

Coarse-granular sediments 

Broken or crushed rock . . 

Dakota sandstone . . . 

Graneros shale . . . .

Greenhorn limestone . 

Carlile shale . . . . .

Niobrara formation . .

Page

20

20

20

21

21

21

21

21

21

21

21

211

ILLUSTRATIONS

Page

Plate 1. Map showing construction materials and geology of Mitchell County, Kans. ... In pocket 

Figure 1. Index map of Kansas showing area covered by this report and by other

construction materials investigations reports .................. 1

2. Chart showing temperature ranges at C'oncordia, Kans.. .............. 1

3. Chart showing precipitation ranges at Beloit, Kans. ................ 1

4. Outcropping Stratigraphic units in Mitchell County, Kans., and their construction

materials .................................. 5

TABLE

Table 1. Summary of materials tests

Page 

In pocket
GEOLOGIC CONSTRUCTION MATERIAL RESOURCES 

IN MITCHELL COUNTY, KANSAS

INTRODUCTION

Purpose of the Investigation

The State Highway Commission of Kansas 

and the United States Geological Survey are cooperating in the compilation of a State-wide inventory construction materials. A field party 

composed of personnel from the two cooperating agencies was sent into Mitchell County, 

Kans. , in the summer of 1948 to investigate 

.sources of engineering construction materials. 

This report of the Mitchell County investigation 

is a part of the general inventory and a contribution to the geologic mapping and investigation 

of mineral resources being made in connection 

with studies of the Missouri River basin. \J

The primary objective of the investigation 

was to accumulate all field and laboratory data 

pertaining to the geologic materials in Mitchell 

County that would be of use in the construction 

of dams, highways, airports, and other engineering structures. Additional geologic data 

are included in this report but only to the extent 

of providing information useful in the development of the prospects reported in the inventory, 

or for the location of other materials required 

for future engineering needs.

Geography 

Area Covered by the Investigation

Mitchell County is in the second tier of 

Kansas counties south of the Nebraska border 

and in the seventh tier west of the Missouri 

border. (See fig. 1.) It comprises 20 townships 

and covers an area of about 720 square miles. 

The county is bounded on the north by Jewell 

and Cloud Counties, on the east by Cloud and 

Ottawa Counties, on the south by Lincoln County, and on the west by Osborne County.

Topography

The average altitude of Mitchell County is 

1, 500 feet. The lowest point, about 1,310 feet, 

is on the Solomon River at the east boundary 

and the highest point, about 1, 885 feet, is a

1 Missouri River Basin, conservation, control, and use 

of water resources: 78th Cong.. 2d sess., S. doc. 191, 

1944.

short distance southeast of Tipton in the area 

known as the Blue Hills.

The two most conspicuous typographic features in the county are the valley of the Solomon 

River and the Blue Hills. The valleys of the 

North and South Forks of the Solomon River, 

which join in the vicinity of Cawker City to form 

the Solomon River, are incised about 50 Teet below the general level; in the eastern part of the 

county, the valley of the Solomon River has been 

incised to a depth of about 150 feet. In the valley 

is an extensive terrace which, in the vicinity of 

Glen Elder, is only slightly more than a mile 

wide but increases in width to almost 4 miles at 

the eastern boundary of the county.

The Blue Hills in the southwestern part of 

Mitchell County stand conspicuously above the 

general level. The hills are buttes and mesas 

capped by the Fort Hays limestone member of 

the Niobrara formation. (See pi. 1 and fig. 4.) 

Their steep slopes have been cut into the Carlile 

shale. The highest of the hills project almost 

300 feet above the surrounding upland plain.

Most of the area of Mitchell County is occupied by a rolling upland plain only moderately 

dissected by the tributaries of the Solomon River 

in the central and northern parts of the county 

and by those of Salt Creek in the southern part. 

The walls of the valleys through which the 

smaller streams flow are gently sloping for the 

most part- a shoulder formed by the Greenhorn 

limestone (see pi. 1 and fig. 4) marks the top of 

man- of the valley walls. I.iterstream areas are 

flat to rounded.

Drainage

Surface drainage in Mitchell County is controlled by the Solomon River ami its tributaries. 

(See pi. 1.) The longest tributaries, Walnut and 

Clay Creeks, head in the Blue Hills and flow 

northward. Salt Creek is the largest stream in 

the southern part of the county. It is another 

tributary of the Solomon River, which it joins in 

the northern part of Saline County.

Climate

Mitchell County is in an area of continental-type climate in which the summers are relatively long and hot and the winters short and
Report in 

prepo ration

Report 

published

Figure I. Index map of Kansas showing areas covered by this report and by other 

construction materials investigations

EXPLANATION

'n *h' ch maximum temperature was more than 90° f. 

(no concrete construction)

in which maximum temperature was between 6I*~9O° F. 

(no interference with any type of construction)

in which maximum temperature was between 4I°-60° F. 

(no Interference n/ira concrete construction; 

no bituminous surfacing* laid)

in which maximum temperature was between 32*-40*F. 

(concrete construction requires protection}

in which maximum temperature was less than 32* F 

the concrete construction)

Data far bath charts

compiled from 

Climatological Data

Kansas Section

far years 1937 to

1946, inclusive.

Issued by

Weather Bureau

United States

Department of Commerce

EXPLANATION

- Days in which precipitation 

I was more than I inch

(no construction activity)

, Days in which precipitation 

9 was between 0.11 and I inch 

(no bituminous surfoc/nffs laid}

I Days in which precipitation 

I was between a trace and O.I inch 

(no interference ir/rn construction}

I Days in which there was

I no precipitation

' (no interference with construction)

Figure 2.-Chart showing temperature ranges at Concordia, Kansas. Figure 3._Chart showing precipitation ranges at Beloit, Kansas
fairly cold. The mean annual temperature is 

about 54 ° F. and ranges from a low of about 

280 F. in January to a high of about 80° F. in 

July. (These figures were interpolated from 

data from nearby stations inasmuch as the 

weather station at fieloit does not maintain records on temperature.) On the average, there 

are 75 cloudy days a year, 110 partly cloudy 

days, and 180 clear days. The ground is 

covered with snow on the average of 28 days of 

the year. The average annual precipitation is 

24. 17 inches. The average date of the first 

killing frost in the fall is October 14 and that 

of the last killing frost in the spring is April 

27. 2/

Figure 2, a chart showing temperature 

ranges at Concordia, Kans. (about 30 miles 

northeast of Beloit), was compiled from Climatological Data 3/ for the years 1937 to 1946, 

inclusive, to provide basic data on temperature in relation to engineering construction. 

The chart indicates, for the 10-year period, 

the number of days each month in which the 

maximum daily temperature fell within certain 

designated ranges based arbitrarily on temperatures important to various phases of engineering construction.

Days in which the maximum temperature 

does not exceed 32° F. occur only from November to March, inclusive, with the maximum incidence of 9. 9 days in January. August 

is the warmest month in the year and on the 

average of 15. 3 days maximum temperatures 

exceeds 90° F. The chart also shows the 

average difference between the daily maximum 

and minimum temperatures for each month. 

The greatest difference in daily temperatures, 

24° F. , is in July; and the least difference, 

18° F. , is in January and February.

Inasmuch as precipitation also conditions 

the number of working days in engineering 

construction, figure 3, a chart showing precipitation ranges at Beloit, Kans. , is presented 

to show the effect of this climatic factor. The 

ranges in precipitation were selected arbitrarily.

As based on a 10-year average 4/ there 

were 19. 7 days in June, for example, in 

which no measurable precipitation fell; 4. 4 

days in which, the precipitation ranged from a 

trace to 0. 1 inch; 4 days in which 0. 11 to 1 

inch of rain fell; and 1. 9 days in which the 

precipitation was more than an inch. Continuing 

rains fall, for the most part, in the late spring 

and early fall and other rainfall is generally in 

the form of showers of .short duration.

Transportation Routes

Mitchell County is served by two railways, 

the Missouri Pacific which extends westward 

across the northern part of the county, and a

branch line of the .Union Pacific that starts in 

Beloit and extends southeastward. It is traversed 

by U. S. Highway No. 24 and Kansas highway 14. 

A second Kansas Highway (No. 128) extends north 

from a point a short distance northwest of Glen 

Elder. East of Beloit, U. S. Highway No. 24 is 

constructed of concrete; west of Beloit it is of 

the black-top type of construction, as is Kansas 

Highway 14. Kansas Highway 9, entering the 

county from the east, is a metaled all-weather 

road as far as its junction with U. S. 24 a mile 

north of Beloit. That part of Kansas Highway 128 

which is included in this county is a metaled allweather road.

County and township roads, for the most 

part, follow section lines. Some of them are 

metaled with materials available locally, whereas others are maintained as earth roads.

The locations of railroads and roads are 

shown on plate 1.

Investigation Procedure

This report is based on field work of the 

reconnaissance type. The base map was provided by the State Highway Commission of 

Kansas (scale: 1 mile to 1 inch). Drainage 

lines were taken from aerial photographs 

(scale: 1 mile to 4 inches) made available by 

the Mitchell County office of the Soil Conservation Service of the United States Department of 

Agriculture. The areal distribution of the strati-- 

graphic units that crop out in Mitchell County 

was then mapped in the field. The mapped stratigraphic units are those recognized by the 

United States Geological Survey 5/and the 

Kansas Geological Survey. 6/ The principal 

emphasis of this report is on construction materials. Geologic problems not critically related to construction materials, therefore, are 

considered to be of secondary importance.

An effort was made to accumulate all existing data pertaining to construction materials 

in the county; these are presented in table 1, a 

summary of materials tests.

Acknowledgments

Appreciation is expressed to the following 

for contributing information found useful in the 

compilation of the geologic map and constructionmaterials data included in this report: the State 

Highway Commission of Kansas at Topeka and 

Manhattan, Kans. , S. E. Horner, chief geologist, R. D. Finney, engineer of materials; and 

W.E. Gibson, engineer of tests; the Mitchell 

County office of the Soil Conservation Service, 

United States Department of Agriculture; and 

the county engineer and residents of Mitchell 

County.

This report, in manuscript form, was reviewed by various members of the State High2 Flora, 8. D., The climate of Kansas: Kansas State 

Board Agr. Bept., vol. 67, no. 285, 320 PP., 1948.

3 U. 8. Dept. Commerce, Weather Bur.: Cliraatological 

Data, Kansas section, 1937-46.

4 (ft), cit., Weather Bur., 1937-46.

9 Wilmarth, M. G., Lexicon of geologic nanes of the 

United States: U. S. Geol. Survey Bull. 896, pts. 1 and 

2, (2,396 pp.), 1938.

8Moore, R. C., Prye, J. C., and Jewett, J. M., Tabular description of outcropping rocks in Kansas: Kansas 

Geol. Survey Bull. 52, pt. 4, 212 pp., 1944.
way Commission of Kansas and the United 

States Geological Survey.

CHARACTERISTICS OF THE OUTCROPPING 

STRATIGRAPHIC UNITS

General

This discussion of the stratigraphic units 

cropping out in Mitchell County emphasizes the 

areal distribution, general characteristics, 

thickness, and the construction materials in 

each geologic formation or member. This part 

of the report presents the geological information required for the location and effective development of the construction materials.

A summary of the data for each geologic 

formation or member is presented in figure 4. 

The areal distribution oi the local stratigraphic 

units is shown on plate 1, a map showing construction materials and geology of Mitchell 

County, Kans. Each unit is indicated by an 

identifying symbol, and its outcrop areas are 

shown by a distinctive pattern. Plate 1 is 

printed in four parts for more convenient use 

in the field; there is an area of overlap 2 

miles wide along the contacts between the parts.

The locations of pits and quarries also 

are shown on plate 1. The Symbols indicate 

whether the pit or quarry is or has been operated or is a prospect, the type of construction 

material available at each site, and the quantity of the material (in units of 10, 000 cubic 

yards) that can be removed under no more than 

moderate overburden (unconsolidated sediments less than 6 feet thick). Most of these 

sources are listed in table 1. Materials represented on the map by inclined letters have not 

been tested and are not listed in table 1. All 

materials sources listed in table 1 are numbered within each materials classification according to the following plan: The numbering 

starts in the northeastern-most township and 

continues along the same tier to the west 

boundary of the county; it is continued in the 

next tier south starting again with the township in the eastern-most range and proceeding 

to the west boundary of the county, and so on. 

Within a township the sources are numbered in 

the same sequence as are the sections of the 

township.

Dakota Sandstone 

Areal Distribution

The Dakota sandstone of Cretaceous age 

is the oldest stratigraphic unit that outcrops 

in Mitchell County. (See pi. 1 and fig. 4.) It 

underlies the entire county but is concealed by 

younger, overlying formations except along the 

Solomon River in the eastern part of the county 

and Salt Creek in the southeastern part. Its 

most extensive area of outcrop is that along the 

north wall of the valley of the Solomon River in 

sees. 22, 23, 26, and 27, T. 7 S. , R. 6 W. 

Several small isolated outcrops occur just east 

of this large one. The formation is well exposed at the base of the south wall of the valley 

of the Solomon River in T. 8 S., R. 6 W. , although its outcrop is masked in many places by 

the younger Sanborn formation. (See fig. 4.) The 

Dakota sandstone makes a bold outcrop at the 

base of the south wall of the valley of Salt 

Creek in T. 9 S. , R. 7 W. Only isolated outcrops of it are mapped on the north side of Salt 

Creek, as in the eastern part of T. 9 S., R. 

7 W. and the southwestern part of T. 9 S. , R. 

6 W. The westernmost exposure of the formation is in the valley of a small stream in the 

SW^SEAsec. 35, T. 9 S., R. 8 W. Outcrops of 

this and other formations of Cretaceous age are 

shown in more extensive areas on a geologic 

map constructed by Landes 7/ which shows, for 

the most part, only the bedrock in the area and 

does not depict the unconsolidated geologic 

formations that mask it in many places.

General Description

The Dakota sandstone, unlike other formations of Cretaceous age cropping out in this 

county, was deposited under nonmarine conditions. As exposed in Mitchell County, this formation consists of about 14 feet of sandstone 

underlain by about 7 feet of shale. (For a typical exposure, see the representative measured 

section,) The sandstone occurs in massive beds 

which show cross-bedding indicative of its nonmarine origin, and is fine-grained and soft. 

Most of the beds are gray orange or red brown 

and weather gray brown or tan gray. Lenses 

and concretionary masses of brown iron oxide 

(iron-stones) are numerous in it.

The beds of shale which are exposed beneath the sandstone in some outcrops are 

usually silty and none ale areous, although thin 

clay zones do occur. The shale is varicolored - 

that is, it exhibits interbedded zones of gray, 

tan, red brown, gray orange, and blue black. 

When weathered, these zones develop lighter 

shades of the same colors. Some layers of 

shale are thin-bedded, others are blocky, and 

still others are platy. Iron-oxide stains occur 

on many of the fracture planes.

Plant fossils are abundant in the Dakota 

sandstone in outcrops in other parts of Kansas 

but were not found in the exposures of the formation in this county. In some places the plant 

remains are so concentrated that they form 

lenses of low-grade coal (lignite), a fact which 

confirms the nonmarine origin of this unit.

The beds of sandstone in the Dakota form 

a conspicuous rounded bench which, in this 

county, is usually near the base of a valley 

wall. The average surface slope of an outcrop 

of this formation is more than 12 percent. IB/ 

The more firmly the sandstone is cemented by 

pore-space deposits of calcium carbonate or 

iron oxide, the more conspicuous the bench it 

forms. All of the beds examined in Mitchell

7 Landes, K. K., The geology of Mitchell and Osborne 

Counties, Kans.: Kansas Geol. Survey Bull. 16, pi. 2, 

1930.

8 Slope data for the outcropping stratigraphic units 

are interpretations of.a reconnaissance soil-conservation 

survey map published by the Soil Conservation Service, 

U. S. Department of Agriculture, in cooperation with the 

Kansas State Agriculture Experiment Station.
Section

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18

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Stratigraphic units

1

>> to

Quaternary

Cretaceous

<o

(U

Pleistocene Recent and 

</> 

8

a>

0 

0

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0)

a. 

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Formations 

and 

members

Alluvium

Terrace 

deposits

San born 

formation

J

1 

|

4> 

O 

<O

= 

0

O

Greenhorn limestone

Fort Hqys 

limestone 

member

Codell 

\ sandstone, 

\ member /

Blue Hill 

shaie 

member

Fairport 

chalky shale 

member

Pfeifer shaie 

member

Jetmore chalk 

member

Hartland sh. 

member

Lincoln Is. 

member

Graneros 

shale

Dakota 

sandstone

Generalized description

Clay and silt interbedded with lenses of local gravel and granific gravelly sand; stream deposited; underlies floodplain and 

occurs in stream channel.

Tan and light brown silt; clayey near surface, lenses of gravel 

in lower partj stream deposited; underlies flat terraces in 

valleys of larger streams.

Gray or brown silt; clayey near surface, lenses of limestone 

gravel and granitic gravelly sand in lower part; stands in 

vertical banks; develops rolling topography.

Thick beds of massrve, cream-colored chalky limestone separated by thin partings of ploty, gray-orange chalky shale; 

shattered zone below surface; marine; fossiliferous; forms 

conspicuous escarpment.

Fine-grained, yellow-brown sandstone and sttlstone; marine.

Dark blue-gray, very thin/bedded, noncalcareous clay shale; 

silty zones near top; interbedded zones of septarlan concretions and selenite crystals; marine; few fossils; erodes to 

form badland-type topography.

As usually exposed, is similar to underlying Pfeifer shale-, marine; 

fossiiiferous; weak outcrop expression.

"Fencepost" bed at top; alternating layers of dark gray to orangegray chalky shales ond thin layers of ton-gray chalky limestones; marine; fossiiiferous; forms hillside bench.

"Sheil-rock" bed at top; alternating layers of blue-gray and tangray chalky shales and limestones; marine-, fossiiiferous; hillside bench.

Alternating thick beds of calcareous, gray and gray-orange siity shales, 

thin beds of tan-gray chalky limestones, and thin seams of bentonite; marine i fossiiiferous; weak outcrop.

Alternating thick layers of thin-bedded, gray to brown shale, thin beds 

of hard crystalline limestone and thin beds of bentonite-, 

marine; fossiiiferous; weak outcrop.

Interbedded thick layers of noncalcareous, thin-bedded, blue-gray clay 

shale, thin seams of bentonite, and lenses of red-brown sandstone; marine; nonfossitiferous; weak outcrop.

Massive, cross-bedded, soft, orange to brown sandstone underlain by noncalcareous, varicolored silt shale; non- marine;

form* rnn.«niriinn<t henrh

Construction 

materials

Aggregate 

Rood metal 

Fill material

Mineral filler 

Fill material

Aggregate 

Mineral filler

Road metal 

Fill material

Road metal 

Structural stone 

Calcareous binder 

Fill material

|

Road metal 

Fill material

Road metal 

Structural stone 

Riprap 

Calcareous binder 

Fill material

Road metal

None

Road metal 

Fill material

Figure 4.-.Outcropping Stratigraphic units in Mitchell County, Kans. and their construction materials.
County are soft and easily pulverized (friable), 

but, in other parts of the State, local beds in 

the formation are so firmly cemented by porespace deposits of silica that they are quartzitic.

Representative Measured Section

This outcrop of the Dakota sandstone was 

measured in a cut along U. S. Highway 24 in 

the NE^NWi sec. 27, T. 7 S. , R. 6 W. :

Feet

Soil: Silt, sandy; reddish-brown . . . . 1.0- 

Dakota sandstone

Sandstone, massive, soft; red-brown; 

weathers gray brown ... ..... 9

Sandstone, powdery, very fine-grained; 

gray-orange; weathers light gray 

orange; intersected by thin veins 

of calcium carbonate and brown iron 

oil ide .......... ....1.2

Sandstone, massive, soft, cross - 

bedded; red-brown; weathers gray 

brown; thin parting of silt about a 

foot below top; ironstone concretionary zone near middle; weathered surface pitted ........ 2. 8

Sandstone, soft, cross-bedded; grayorange becoming tan in basal part; 

weathers tan gray; numerous interbedded thin partings of silt. . . . . 1. 1

Siltstone, very soft except for inter - 

bedded lenses of harder material, 

cross-bedded; gray, red-brown, 

gray-orange, and tan; weathers 

tan; small ironstone concretions 

scattered throughout ....... 8. 2

Shale, silty, noncalcareous; thinbedded; mottled dark-gray, tan, 

and gray-orange; weathers tan . . .0. 2

Ironstone lens, very hard; red-brown .0. 2

Shale, silty, noncalcareous; thinbedded; mottled tan and grayorange; weathers tan ...... .0.3

Shale, silty, noncalcareous; crossbedded; dark-gray; weathers gray; 

interbedded thin lenses of yellow 

silty shale ............ 1. 1

Shale, clayey, noncalcareous; 

platy; blue-black; weathers light 

blue black; soft, red-brown ironstone concretions scattered 

throughout ............. 8

Shale, clayey but contains some

silt-size particles, noncalcareous; 

blue-black; weathers light blue 

black; ironstone concretions scattered throughout ......... 1.0

Shale, silty, noncalcareous; platy; 

blue-black; weathers light blue 

black; iron stains on fracture 

planes ............ . 2.0

Total thickness exposed (base covered)20. 9

Thickness

The greatest thickness of the Dakota 

sandstone exposed at the surface in this county

is about 25 feet, and most of the outcrops are 

from 10 to 15 feet thick. Only the uppermost 

part of the formation is exposed locally and its 

total thickness is probably in excess of 200 

feet.

Construction materials. --Materials from 

the Dakota sandstone in Mitchell County are 

used as road metal and fill material.

Graneros Shale

Areal Distribution

The Graneros shale and the overlying 

formations of Cretaceous age (see fig. 4) 

cropping out in Mitchell County are of marine 

origin. The Graneros shale crops out only in 

the east-central and south-central parts of the 

county. (See pi. 1.) Individual outcrops are 

generally concealed beneath the younger Sanborn formation and are thus of limited areal 

extent. The most extensive exposure is that 

along the south wall of the valley of Salt Creek 

in the southern part of T. 9 S. , R. 7 W. and 

the eastern part of the next township west. The 

formation is here exposed immediately above 

an extensive outcrop of the Dakota sandstone. 

Very small isolated outcrops occur in some of 

the valleys of streams tributary to Salt Creek 

and, in the eastern part of the county, in valleys 

of streams tributary to the Solomon River.

General Description

The Graneros is predominantly a noncalca^-eous clay shale but includes some thin 

silty zones and other slightly calcareous zones. 

The shale is soft and thin-bedded. The beds 

are usually gray or blue gray and weather 

light gray or tan. Some of the fractures in the 

shale are filled with thin veins of calcium carbonate (calcite). Numerous small crystals and 

occasional veins of a variety of gypsum 

(selenite) are scattered throughout the shale. 

Many of the fracture planes are stained with 

brown iron oxide. This shale is generally nonfossiliferous.

Included in the formation are interbedded 

layers and thin seams of white to creamcolored bentonite. The weathered surface of 

the bentonite is orange-colored or reddish 

brown. Although most of the bentonitic layers 

are no more than 0. 2 foot thick, a bed a foot 

thick is remarkably persistent in the uppermost part of the formation. Bentonite is altered 

volcanic ash, and its volume is greatly increased when it becomes saturated with water.

The Graneros shale also includes interbedded thin layers and lenses of sandstone. The 

sandstone is thinbedded and is usually slightly 

calcareous. Its color is red brown because of 

the presence of iron oxide which, together with 

calcium carbonate, was deposited in the porespaces between the sand grains and serves as 

the cementing substance.

This formation, because of its softness, 

makes only a very weak outcrop. It is largely 

masked by the slopewash and gravity-moved
sediments (colluvium) mapped on plate 1 as 

part of the Sanborn formation. The surface 

slope developed in an outcrop of the Graneros 

shale is usually more than 12 percent.

Representative Measured Section

The entire thickness of the Graneros 

shale is exposed in a road cut in the 

sec. 24, T. 8S., R. 6 W. as follows:

Feet

Overlain by the Lincoln limestone member 

of the Greenhorn limestone

Graneros shale:

Shale, clayey, somewhat calcareous; 

brown and gray; weathers light 

gray; numerous crystals of 

selenite ............. 0. 9

Bentonite; cream-colored; weathers

orange and red .......... 1. 0

Shale, clayey, noncalcareous; soft; 

very thin-bedded; dark blue-gray; 

weathers light gray; numerous small 

crystals of selenite throughout and 

fractures filled with thin veins of 

the same material; thin lenses of 

iron-stained sandstone in upper part; 

interbedded thin seams of bentonite 

throughout ............ 10. 1

Sandstone, slightly calcareous; thinbedded; red-brown; weathers brown, 

occasional thin veins of calcite . . . 0.5

Shale, clayey, noncalcareous; soft; 

thin-bedded; blue-gray; weathers 

light blue gray; small crystals of 

selenite scattered throughout; 

fractures filled with thin veins of 

brown iron oxide; several thin 

lenses of iron-stained sandstone in 

upper part ............ 6.1

Shale, silty, noncalcareous; soft; 

thin-bedded; red-brown; weathers 

tan ... ............ 0.6

Shale, clayey but with some siltsize particles, noncalcareous; soft; 

thin-bedded; gray; weathers 

light gray .........'... 2. 25

Total thickness (underlain by the 

Dakota sandstone). . . . . . . . .21.45

Thickness

The outcrop of the Graneros shale cited 

as the representative measured section is the 

thickest exposure of this formation found in 

Mitchell County. In most outcrops, a thickness 

of 10 feet or less of the formation is exposed at 

the surface.

Construction Materials

So far as is known, materials of the 

Graneros shale have not been used in engineering construction.

Greenhorn Limestone 

Areal Distribution

The second Cretaceous formation of 

marine origin, the Greenhorn limestone,

crops out extensively in the eastern part of 

Mitchell County but, for the most part, is 

buried beneath younger formations farther 

west. (See pi. 1. and fig. 4.) This formation 

forms the greater part of the walls of the valleys of the Solomon River and its tributaries 

in the vicinity of Beloit. It is conspicuously 

displayed, also, throughout much of the 

watershed of Salt Creek. The Greenhorn 

limestone caps most of the interstream 

areas in eastern Mitchell County but is concealed beneath the Sanborn formation except 

along the edges of the deeper valleys. Although 

thin and usually discontinuous outcrops are 

mapped on plate 1 along the Solomon River as 

far west as Cawker City, the Greenhorn limestone is concealed beneath a younger Cretaceous formation, the Carlile shale, in the 

western part of the county.

General Description

The Greenhorn limestone is shown on 

plate 1 as a single map unit (Kg) but the 

description of this formation will be based 

up'on the members of which it is composed. 

These are, in upward order: the Lincoln 

limestone member, Hartlant shale member, 

Jetmore chalk member, and Pfeifer shale 

member.

1. Lincoln limestone member of the 

Greenhorn limestone. --The Lincoln member 

is composed of alternating thick beds of shale, 

thin layers of limestone, and thin seams of 

bentonite. The greater part of its thickness, 

therefore, is shale. The shale is silty for the 

most part and heavily impregnated with calcium carbonate. It is soft and thin to very 

thin-bedded, although a few thin layers of 

platy shale appear in the upper part of the 

member. The unweathered shale shows zones 

of tan gray, gray orange, gray brown, brown, 

and dark gray; the weathered rock is light 

gray or tan gray. Thin fracture fillings of 

calcite and selenite occur in some of the beds. 

Iron-oxide stains are common along fracture 

planes and concretions of the same material 

are present in limited numbers.

Whereas most of the limestones of the 

Greenhorn limestone are soft and chalky, those 

in the Lincoln member are hard and crystalline. 

The beds of limestone range from 0. 1 to 0. 6 

foot in thickness with one 0. 6-foot-thick bed 

near the base and one 0. 6-foot-thick bed near 

the top of the member. The beds are generally 

massive but some near the top have platy 

structure. The rock is usually some shade of 

brown and weathers tan gray. A strong odor of 

oil can be detected in freshly broken blocks.

The seams of bentonite interbedded with 

the shales and limestones range from 0.05 to 

0. 3 foot in thickness. This material shows a 

blocky structure and is white or light gray 

when fresh but weathers gray orange or red 

brown.

Unlike the underlying Graneros shale, 

the Lincoln limestone member of the Greenhorn limestone is generally fossiliferous. 

Clams, fish scales, and shark teeth are most
abundant, and coiled shellfish (cephalopods) 

are present in limited numbers. Although 

most of the beds of limestone contain fossils, 

only the shales in the upper part of the member . 

are fossiliferous.

Landes jj/states that the Lincoln limestone 

is at least 22 to 24 feet thick; this is confirmed 

by a complete section of the member (see 

representative measured section) which shows 

a total thickness of 22 feet. Outcrops of the 

Lincoln limestone member are few. The bed 

of limestone 0. 6-foot thick near the top of 

the member forms an identifiable bench on 

some hillsides.

2. Hartland shale member of the Greenhorn limestone. --The Hartland shale member, 

as the Lincoln limestone member below it, is 

composed of thick beds of shale, thin layers of 

limestone, and thin seams of bentonite. However, the shales of the Hartland are more 

chalky than those of the Lincoln. Limestones of 

the Hartland are generally chalky rather than 

crystalline. The beds of shale in this member 

are composed predominantly of chalky silt but 

some thin zones of clay are also present. The 

shale is generally soft and is platy to thinbedded. Alternating zones of light gray, gray 

orange, and, less commonly, red brown are 

conspicuous on unweathered surfaces; weathered 

exposures are usually tan gray but may show 

zones of light gray and gray orange. Very 

thin partings of calcium carbonate occur in 

some parts of the member, and iron-stained 

zones are found at various levels.

The beds of limestone in the Hartland 

shale member range from 0. 1 foot to 2. 2 feet 

in thickness. Although most of the limestone 

is soft and chalky, some of it is hard and 

crystalline and has much the same appearance 

as the limestone of the Lincoln member. The 

beds are generally thin-bedded to blocky but 

are somewhat massive in the upper part. The 

limestones are generally gray or tan gray, 

occasionally red brown, and almost all of them 

weather tan gray. The beds of limestone characteristically are broken by very thin partings 

of chalky shale. Iron-stained zones occur in 

some of the thicker limestones.

The interbedded seams of bentonite range 

from 0. 05 to 0. 65 foot in thickness. This material, white or light-gray where unweathered, 

is present as orange or red-brown streaks on 

weathered outcrops. It is generally blocky but 

some seams are finely granular.

Clam shells, fish scales, and shark 

teeth are numerous or abundant in some zones 

of this member. The Hartland shale member 

develops a poor outcrop expression. Most of 

its exposures are low on the walls of the deeper 

valleys in the eastern part of the county.

The maximum thickness exposed in 

Mitchell County is 27 feet but a typical outcrop shows only 10 or 12 feet of the total 

thickness.

90p. cit., p. 29.

3. Jetmore chalk member of the Greenhorn limestone. --The Jetmore chalk member 

is composed of -alternating beds of shale and 

limestone; most of the limestones range from 

0. 2 to 0. 4 foot in thickness and the shales 

from 0. 8 to 1 foot in thickness. The proportionate thickness of the limestones, therefore, 

is greater in the Jetmore than it is in the underlying Hartland shale and Lincoln limestone 

members.

The beds of shale are silty and highly 

calcareous. They tend to be thin-bedded in the 

lower part of the member and platy in the upper part. The lower beds are generally blue 

gray and weather light blue gray; whereas the 

upper beds are generally gray orange and 

weather tan gray. Thin seams of calcite are 

scattered throughout the shale zones, and 

iron-oxide stains are common.

The top of the Jetmore chalk member is 

defined as the top of the "shell-rock" bed. 

The name "shell-rock" refers to the great 

abundance of clam shells that the bed contains. 

This is a massive bed of limestone and is 

usually slightly more than a foot thick. The 

beds of limestone lower in the member are 

less thick and chalky. They are tan gray in the 

upper part and blue gray in the lower part. 

Iron-oxide stains and ferruginous concretions 

are typical of the limestones.

Fossils, especially clams, are numerous 

to abundant in the beds of limestone but are 

less numerous in the beds of shale. The coiled 

shells of cephalopods are occasional fossils in 

the Jetmore chalk member.

The greatest thickness of the Jetmore 

chalk member measured in Mitchell County is 

18 feet and many of its exposures are from 12 

to 15 feet thick. Outcrops of the Jetmore are 

easily identified by the close-spaced beds of 

chalk it contains and by the shell-rock bed 

which makes a prominent shoulder on many of 

the valley walls. One or more of the lower 

limestones may form a less well developed 

bench below the shell-rock shoulder. The Jetmore outcrops at many places in the general 

area of outcrop of the Greenhorn limestone.

4. Pfeifer shale member of the Greenhorn limestone. --The Pfeifer shale member 

is composed of alternating beds of chalky 

shale, which average 0. 5 foot in thickness; 

chalky limestones, which average 0. 2 foot in 

thickness; and occasional thin seams of 

bentonite about 0. 1 foot in thickness. The beds 

of shale are platy and tan gray or orange gray 

in the upper part of the member, and are 

thin-bedded and dark gray in the lower part. 

Most of the upper beds weather gray orange 

and the lower ones weather light gray.

The top of the member is defined as the 

top of the "Fencepost" bed. This is a massive layer of tan-gray limestone characterized by a red-brown band of iron oxide extending through the middle part of the limestone. The bed is 0. 6 foot thick. Its name indicates the use that was made of this lime-
stone in earlier years; at the present time it 

is used as building stone.

The other beds of limestone in the 

Pfeifer shale member are chalky soft massive 

and light gray or tan gray. Many of them are 

marked by thin red-brown streaks of iron oxide.

Several thin seams of bentonite are interbedded with the shales of this member. 

Despite their thinness, each one of them can 

be traced over a wide area. The weathered 

bentonite is white, but, as exposed in the face 

of an outcrop, it is a streak of gray orange or 

red brown.

Another persistent bed included in this 

member is the one known as the "sugar sand. " 

It is 0. 2 foot thick and occurs about 5feet below the base of the "Fencepost" bed. It is 

composed of small grains of calcite and is 

gray orange.

Fossilized clam shells are abundant in 

the beds of limestone but are not so numerous 

in the beds of shale.

The total thickness of the Pfeifer shale 

member in Mite hell County is 18 feet. Most 

of that thickness is exposed in many of the 

outcrops of the member. This shale has a 

strong outcrop expression and is readily identified by the "Fencepost" bed, which forms a 

conspicuous angular shoulder at the top of the 

walls of many valleys; the shoulder is marked 

by crescent-shaped quarries which were 

opened wherever the over-burden was thin.

Representative Measured Sections

1. The section of the lower part of the 

Pfeifer shale member exhibits the full thicknesses of the Hartland shale and Lincoln 

limestone members. It was measuredin a road 

cut in the SE^SE^ sec. 24, T. 8 S. , R. 6 W. , 

as follows:

Feet

Soil:

Greenhorn limestone:

Jetmore chalk member (0. 4 foot present)

Limestone, chalky; red-brown to 

tan-gray; weathers light red 

brown; concretions of iron oxide in 

middle part; thin seams of 

calcite. Clam shells, fish 

scales, shark teeth, and occasional shellfish ....... .4

Hartland shale member (27. 18 feet thick)

Bentonite; tan-gray ....... .2

Shale, silty, calcareous; thinbedded; tan-gray; weathers

light gray; iron-oxide stains

on fracture surfaces. Clams,

fish scales, and shark teeth ... 2.4

Shale, silty, calcareous; thinbedded; red-brown; weathers 

tan gray; iron-oxide stains 

on bedding planes. Fish scales 

and some clam-shell fragments . 2.65

Feet

Limestone, chalky; soft; tangray; weathers light gray. ... 1.5

Shale, silty, calcareous; thinbedded; mottled tan-gray and 

gray-orange; weathers tan 

gray ............. .85

Bentonite, red-brown and grayorange ............ .65

Limestone, chalky; soft; lightgray; weathers tan gray; iron 

stains on fracture surfaces ... .3

Shale, silty, calcareous; thinbedded; mottled gray-orange 

and red-brown; weathers 

light gray; iron stains on 

bedding planes. Clarn-shell 

fragments, fish scales, and 

shark teeth .......... 2. 1

Limestone, chalky; tan-gray; 

weathers light tan gray; 

occasional thin calcite 

seams and iron stains. 

Clam-shell fragments, fish 

scales, and shark teeth .... 0. 3

Shale, silty, calcareous; thinbedded; red-brown; weathers 

gray orange; iron-stained. 

Clam-shell fragments and 

fish scales .......... .45

Shale, clayey, calcareous; blocky;

gray-orange; weathers gray . . .35

Shale, very silty, calcareous; 

massive; mottled tan and redbrown; weathers light gray; 

iron stains on fracture surfaces. Clam-shell fragments 

and fish scales ........ 1.3

Bentonite; orange ........ .2

Limestone; thin-bedded with shale 

partings; gray-orange; 

weathers gray. Clams 

and fish scales ........ 2. 2

Limestone, thin-bedded; lightgray; weathers tan gray; 

occasional small concretions of iron oxide ..... 0.2

Shale, silty, calcareous; platy; 

mottled light-gray and redbrown; weathers tan gray; 

occasional seams of calcite. 

Clam shells, fish scales, and 

shark teeth .......... 1.4

Bentonite; orange ........ .03

Shale, silty, calcareous; platy; 

mottled light-gray and reddishbrown; weathers tan gray; occasional thin seams of calcite. 

Clam shells, fish scales and 

teeth .. t .......... .8

Bentonite; orange ........ .1

Shale, silty, calcareous; platy; 

mottled light-gray and 

red-brown; weathers tan 

gray; occasional seams of 

calcite. Clam shells, fish 

scales and teeth ....... 3.3

Bentonite; orange ....... 0.2

Shale, silty, calcareous; platy; 

mottled gray-orange and gray; 

weathers.tan gray. Clam 

shells, fish scales and teeth . . .3
Feet Feet

Bentonite; mottled gray-orange

and brown. .......... .2

Shale, silty, calcareous; platy; 

brown; weathers tan gray. Clam 

shells, fish scales and teeth . . 1.0 

Bentonite; orange; thin lenses of

iron oxide .......... .15

Shale, silty, calcareous; brown; 

weathers tan gray. Clam shells, 

fish scales and teeth ...... .6

Limestone; thin-bedded; crystalline; 

beds separated by very thin 

shale partings; gray; weathers 

tan gray. Clam shells, fish 

scales and teeth ........ .5

Shale, silty, calcareous; platy; 

mottled gray-orange and lightgray; weathers tan gray; occasional very thin beds of gray 

crystalline limestone. Clam 

shells, fish scales and teeth. . . 1.3 

Bentonite; orange ........ .05

Limestone, chalky; blocky; grayorange; weathers gray. Clam 

shells, fish scales and teeth . . .1 

Bentonite; orange ........ .1

Shale, silty, calcareous; platy; 

occasional very thin partings 

of lime stone,v brown to reddishbrown; weathers tan gray. Clam 

shells, fish scales and teeth . . 1. 4 

Lincoln limestone member (22.03 

feet thick) Limestone, crystalline; 

thin-bedded; thin partings of 

silty shale; red-brown; weathers 

tan gray. Clam shells, fish 

scales and teeth ........ 1.0

Limestone, crystalline; tan-gray; 

weathers gray. Clam shells, 

fish scales and teeth ...... .3

Shale, silty, calcareous; platy; 

brown; weathers gray. Clam 

shells and fish scales ..... .2

Bentonite; orange ........ 0. 05

Limestone, chalky; thin-bedded; 

light-gray; weathers tan gray. 

Fish scales .......... .15

Shale, silty, calcareous; platy; 

brown to black; weathers gray; 

occasional thin limestone 

seams ............ .3

Shale, silty, calcareous; platy; 

brown to dark-brown; weathers 

tan gray; occasional thin 

seams of calcite ....... .2

Bentonite; gray-orange ..... .2

Limestone, chalky; platy; very 

soft; dark-gray and red-brown; 

weathers tan gray; occasional 

irregular carbonaceous seams. 

Clam shells, fish scales, and 

shark teeth .......... .4

Shale, silty, ^calcareous; thinbedded; dark-gray and graybrown; weathers gray. Fish 

scales and shark teeth ..... .3

Bentonite; red-brown ...... 0.3

Limestone, chalky; gray-brown; 

weathers tan gray. Fish 

scales abundant ........ .05

Shale, silty, calcareous; thinbedded; gray-brown; weathers 

light gray. Fish scales. . . . .

Limestone, crystalline; platy; 

hard; red-brown; weathers 

tan gray. Fish scales and 

shark teeth .........

Shale, silty, calcareous;.thinbedded; reddish-brown; 

weathers tan gray; iron-oxide 

concretions in middle part . .

Shale, clayey, calcareous; very 

thin-bedded; gray-brown to 

black; weathers tan gray; 

irregular thin lenses of hard, 

crystalline gray-brown limestone. Fish scales. .....

Bentonite; mottled cream and 

red-brown .........

Shale, clayey, calcareous; thinbedded; dark-gray; weathers 

light gray; iron-oxide streaks 

throughout; small crystals of 

selenite along bedding planes .

Shale, very silty, calcareous; 

thin-bedded; red-brown; 

weathers tan gray; thin seams 

of bentonite; crystals of 

selenite along fractures . . .

Shale, silty, calcareous; thinbedded; tan-gray; thin calcareous partings ......

Limestone, crystalline; grayorange; weathers light gray. 

Clam shells. ........

Shale, silty, calcareous; thinbedded; gray-orange; weathers 

light gray; thin calcareous 

layers ...........

Limestone, crystalline; darkgray; weathers light gray. 

Abundant shark teeth. ....

Shale, silty, calcareous; thinbedded; gray-brown; weathers 

gray; interbedded very thin 

layers of crystalline limestone ...........

.08 

. 1 

.4

4.0 

.3

4.9

5.1

1.4

.6

.8 

.2

0.7

Underlain by the Graneros shale. 2 

Complete sections of the upper two members 

of the Greenhorn limestone, the Pfeifer shale 

member and Jetmore chalk member, were 

measured in a road cut in the NW^NEj^sec. 

10, T. 7 S. , R. 8 W. :

Feet

Greenhorn limestone:

Pfeifer shale member (18. 18 feet thick) 

"Fencepost" limestone bed; 

massive; light-gray with 

red-brown streak through 

middle; weathers tan gray. 

Occasional clam shells 

and rare shells of 

cephalopods ......... 0.6

Shale, silty, calcareous; 

platy; tan; weathers 

dark gray. Clam shells .... .3

10
Feet Feet

Shale, silty, calcareous; platy; 

mottled light-gray and grayorange; weathers gray. A few 

clam shells .... ....

Shale, silty, calcareous; platy; 

gray-orange; weathers 

light gray orange. A few clam 

shells ... ........

Bentonite; mottled-gray and grayorange ..........

Shale, silty, calcareous; platy; 

mottled gray-orange and 

light-gray; weathers light 

gray. Occasional clam shells . 

Limestone, soft; light-gray 

streaked with gray-orange; 

weathers gray; lenticular. 

Occasional clam shells ....

Shale, silty, calcareous; platy; 

mottled gray-orange and lightgray; weathers light gray 

orange. Occasional clam 

shells .............

Limestone, hard; tan-gray; 

weathers tan. A few clam 

shells ............

Shale, silty, calcareous; platy; 

gray-orange with streaks of 

light-gray; weathers light 

gray orange ..........

Bentonite; gray-flecked with

gray-orange .........

Shale, silty, calcareous; somewhat blocky; light-gray with 

streaks of gray-orange; 

weathers light gray orange. 

Fish scales .........

Granular calcite; "sugar sand" 

bed; mottled-cream and 

yellow ............

Shale, silty, calcareous; platy; 

light-gray; weathers light 

orange. Fish scales and a 

few clam shells ........

Limestone, hard; red-brown with 

light-gray band at top and 

base. Clam shells .......

Shale, silty, calcareous; platy; 

gray-orange; weathers gray. 

A few clam shells .......

Bentonite; mottled-white and

red-brown ..........

Shale, silty, calcareous; platy; 

gray-orange; weathers light 

gray orange. Fish scales and 

a few clam shells .......

Limestone, hard; gray-orange; 

weathers light gray; lenticular. 

Some clam shells .......

Shale, silty, calcareous; platy; 

gray-orange; weathers light 

gray orange. Clam shells . . . 

Limestone, hard; light-gray; 

weathers tan gray; thin calcite 

streaks throughout. 

Clam shells ..........

Shale, silty, calcareous; platy; 

gray-orange. Clam 

shells. ............

0.2

.2

. 1

.6 

.2

1.4 

0.2

.9 

.01

.6 

.25

.2 

.3

0.1

. 1

.6 

.3

1.4

.3

.5

Limestone, hard; light-gray; 

weathers tan gray; lenticular; 

thin seams of calcite throughout. 

Clam shells ..........

Shale, silty,. calcareous; platy; 

gray-orange; weathers light 

gray orange; thin seams of 

calcite throughout. Clam 

shells ............

Limestone, hard; light-gray; 

thin seams of calcite 

scattered throughout. Clam 

shells ............

Shale, silty, calcareous; platy; 

gray-orange; abundant seams of 

calcite. A few clam shells . . .

Limestone, hard; gray; weathers 

light gray; calcite seams; 

lenticular. Clam shells . . . .

Shale, silty, calcareous; platy; 

gray-orange; abundant seams of 

calcite. Clam shells ......

Limestone, hard; light-gray.

Clam shells .........

Bentonite; mottled-gray and

orange ............

Shale, silty, calcareous; platy; 

dark-gray; weathers gray. A 

few clam shells ........

Limestone; lenticular;, light-gray. 

Abundant clam shells ......

Shale, silty, calcareous; platy; 

dark-gray with streaks of grayorange; weathers dark gray; 

seams of calcite. Abundant 

clam shells ..........

Limestone; lenticular; gray; 

weathers light gray; seams 

of calcite. Abundant clam 

shells ............

Shale, silty, calcareous; platy; 

dark-gray mottled with grayorange; weathers gray. A few 

clam shells .........

Limestone; irregular; light-gray. 

Abundant clam shells .....

Shale, silty, calcareous; soft; 

thin-bedded; dark-gray mottled 

with gray-orange becoming blue 

black near base; weathers dark 

gray. A few clam shells ....

Limestone; irregular; tan; 

weathers light gray. A few 

clam shells ...... ...

Shale, silty, calcareous; soft; 

thin-bedded; blue-black; 

weathers light blue black. 

A few clam* shells .......

Limestone; irregular; tan; 

weathers light gray. A few , 

clam shells ........'..

Shale, silty, calcareous; thinbedded; blue-black; weathers 

light blue black. A few clam 

shells . . ..........

Limestone, hard; tan-gray; 

weathers light gray; a few 

seams of calcite. Abundant 

clam shells ..........

0.3

.5

.2 

.5 

.2

.6 

.02 

0.02

.2 

.2

.4 

.2

.3 

. 1

0.3 

. 1

.2

. 1

.7 

.2

11
Feet Feet

Shale, silty, calcareous; platy;

gray-brown. A few clam

shells ............ 0.6

Limestone; irregular; gray-orange

with irregular red-brown

streaks in middle part;

weathers light gray orange.

A few clam shells ....... .1

Shale, silty, calcareous; platy;

gray-brown. A few clam shells . . 5 

Limestone, hard; irregular; tan;

weathers tan gray; some seams

of calcite. Abundant clam

shells ............ .1

Shale, silty, calcareous; platy;

gray-brown. A few clam

shells ............ .7

Shale, silty, calcareous; thinbedded; blue-black; weathers

light blue black. A few clam

shells ............ .4

Shale, silty, calcareous; platy;

mottled tan-gray and grayorange; weathers light gray

orange; calcite seams. Clam

shells, fish vertebrae ..... .9

Jetmore chalk member (18. 20 feet thick) 

"Shell-rock" limestone bed;

massive; hard; tan-gray.

Great abundance of clam

shells ............ 1.1

Shale, silty, calcareous; platy;

light-gray mottled with some

gray-orange; weathers light

gray orange. A few clam

shells ............ 1.2

Limestone, hard; irregular;

light-gray; weathers tan. A

few clam shells ........ .1

Shale, silty, calcareous; platy;

light-gray mottled with grayorange; weathers light gray

orange. A few clam shells ... .3 

Limestone, hard; irregular; tangray; numerous seams of

calcite. Clam shells ..... .2

Shale, silty, calcareous; platy;

mottled light-gray and grayorange; weathers light gray

orange; numerous seams of calcite. Abundant clam shells . . .9 

Limestone, hard; gray; weathers

tan gray; irregular thin seams

of calcite. Abundant clam

shells ............. 0.3

Shale, silty, calcareous; platy;

gray-orange with blue-black

layer near top; weathers

light gray orange; abundant

irregular seams of calcite.

Clam shells ......... .9

Limestone, hard; light-gray.

Abundant clam shells ..... .3

Shale, silty, calcareous; platy;

gray-orange with blue-black

zone in middle part; weathers

light gray orange; thin seams

of calcite. Clamshells .... .9

Limestone, hard; massive; gray; 

weathers light gray; ironstone 

concretions in middle part. 

Clam shells ......... .9

Shale, silty, calcareous; thinbedded; blue-black; weathers 

light blue black. A few clam 

shells ............. .8

Limestone, hard; gray; weathers 

light gray; ironstone concretions 

in middle part. Clam shells . . 0.2

Shale; silty, calcareous; thinbedded; blue-black; weathers 

light blue black. A few clam 

shells ............ .8

Limestone, hard; dark-gray; 

weathers gray; somewhat 

crystalline .......... .2

Shale, silty, calcareous; thinbedded; blue-black; weathers 

light blue black. A few clam 

shells ............ .8

Limestone, hard; dark-gray; 

weathers gray; irregular thin 

seams of calcite; iron-oxide 

stains on weathered surface. 

Clam shells ......... .3

Shale, silty, calcareous; thinbedded; blue-black; weathers 

light blue black. A few clam 

shells ............ 1.9

Limestone, soft; light gray; ironoxide concretions in middle 

part; hard crystals inside concretions; tendency to shatter 

and split. A few clam shells . . 0.4

Shale, silty, calcareous; thinbedded; blue-black; weathers 

light blue black; somewhat 

jointed. A few clam shells ... .7

Limestone, hard; gray; weathers

tan gray. A few clam shells . . .3

Shale, silty, calcareous; thinbedded; blue-black; weathers 

light blue black. A few clam 

shells ............ .7

Limestone; irregular; blue-gray; 

weathers light blue gray. A 

few clam shells ........ .2

Shale, silty, calcareous; thinbedded; blue-black; weathers 

light blue black; somewhat 

jointed. A few clam shells ... 1.0

Limestone, hard, light-gray; 

iron-oxide concretions in 

middle part. A few clam 

shells ............. 0. 3

Shale, silty, calcareous; thinbedded, blue-black; weathers 

light blue black. A few clam' 

shells ............ 1.0

Limestone, hard; mottled gray 

and gray-orange; weathers 

tan gray. A few clam shells . . .2

Shale, silty, calcareous; thinbedded; blue-black; weathers 

light blue black. A few clam 

shells ............ .9

12
Feet

Limestone, hard; mottled-gray and 

gray-orange; weathers light 

gray; iron-oxide conretions and 

stains in middle part; tends to 

split near middle. A few clam 

shells ............ .4

Underlain by Hartland shale member. 

Thickness

The total thickness of the Greenhorn 

limestone in Mitchell County is about 81 feet 

and is distributed among the four members as 

follows: Lincoln limestone member 22 feet; 

Hartland shale member 27 feet; Jetmore 

chalk member, 18 feet; and Pfeifer shale member 18 feet. The entire formation does not 

crop out at any one place in the county but a 

number of exposures of about half of the formation were noted. Surface slopes developed 

in outcrops of the Greenhorn limestone range 

from 2 to 12 percent or more, and are usually 

from 7 to 12 percent.

Construction Materials

Materials from the Greenhorn limestone in Mitchell County are used as: road 

metal, structural stone, riprap, calcareous 

binder, and fill material.

Car 111 e Shale 

Areal Distribution

The Carlile shale, the third Cretaceous 

formation of marine origin, is exposed in 

only a few places in the eastern part of the 

county, but crops out widely in the western 

part. (See pi. 1 and fig. 4.) The easternmost 

exposures are those at the top of the valley 

walls of some of the streams tributary to the 

Solomon River near Beloit. The outcrops become 

more numerous and more extensive in the western part of the watershed of the Solomon River. 

The Carlile is well exposed in the watershed of 

Salt Creek in the south-central part of the county. However, its outcrops are most extensive 

and most numerous in the area of the Blue Hills 

southeast of Tipton. The Carlile shale underlies 

many of the interstream areas in the western 

two-thirds of the county but is concealed beneath 

the younger Sanborn formation and, in the Blue 

Hills area, beneath the Fort Hays limestone 

member of the Niobrara formation. The formation dips at a low angle toward the northwest, 

as do all of the formations of Cretaceous age.

General Description

The Carlile shale is shown on plate 1 as a 

single map unit (Kc) but the description of this 

formation will be based on the members of 

which it is composed. These are, in upward 

order, the Fairport chalky shale member, Blue 

Hills shale member, and Codell sandstone 

member.

1. Fairport chalky shale member of the 

Carlile shale. --The lower part of the Fairport

chalky shale member is very similar to the 

Pfeifer shale member of the Greenhorn limestone from which it is arbitrarily separated by 

the "Fencepost" limestone bed. This basal 

member of the Carlile shale consists of interbedded shales, limestones, and occasional thin 

seams of bentonite. The shales are chalky and 

thin-bedded for the most part but are very 

thin-bedded in some zones and blocky in others. 

They are tan gray and weather cream. Many of 

the fracture and bedding planes are stained 

red brown by iron oxide. The beds of shale are 

usually slightly more than a foot thick.

The limestones in the Fairport member are 

chalky and soft. They occur in massive beds, 

some of which weather platy. Their color is 

cream in fresh exposures, and buff in weathered 

exposures. Many of the beds, as those in the 

Pfeifer shale member of the Greenhorn limestone, are marked by reddish-brown streaks of 

iron oxide. The limestones in the lower part of 

the member tend to be nodular and average 

0. 3 foot in thickness.

Only occasional thin seams of bentonite 

are included in the Fairport chalky shale member. 

They are usually from 0. 05 to 0. 02 foot thick, 

and appear as red-brown or gray-orange streaks 

in (the face of) a weathered outcrop.

Clam shells are numerous in both shale 

and limestone. A section of the Fairport chalky 

shale member measured by Landes 10/ in the 

eastern part of Osborne County indicates that 

it is about 100 feet thick. The only conspicuous 

outcrops of this member are those of its basal 

part which are frequently associated with outcrops 

of the underlying Pfeifer shale member. The 

upper part of the Fairport chalky shale member 

is largely masked by the younger Sanborn 

formation. Surface slopes developed in the 

basal part of this member are generally from 

7 to 12 percent or more; those of the upper 

part generally range from 2 to 5 percent.

2. Blue Hill shale member of the Carlile 

shale. --The Blue Hill is a noncalcareous clay 

shale (although some silty zones are included 

in its upper part) and is black or dark blue 

gray. The silty zones contain numerous limecemented concretions some of which are as 

much as 8 feet in diameter. The clay shales, 

which predominate in the member, are very 

thin bedded; the silt shales, however, tend to 

be platy. Iron-oxide stains are found along 

many of the fracture surfaces.

Several zones of spheroidal concretions 

(septaria), averaging from 1 to 3 feet in diameter, are included in the clayey middle and 

lower parts of the Blue Hill shale member. 

They are formed by the intersection of 

radiating veins and concretric shells of calcium carbonate. Frequently they develop 

around the coiled shell of a cephalopod.

Numerous zones of selenite crystals are 

included in the Blue Hill member and, upon 

weathering and erosion of their shale matrix,

. clt., pp. 21-23.

13
reflect sunlight in a manner that gives a hillside a sparkling appearance. The crystals 

average about 2 inches long but may be as 

much as 5 or 6 inches long.

The total thickness of the Blue Hill 

shale member is about 200 feet and the 

greater part of that thickness is exposed on 

the sides of the Blue Hills. This member 

has a bold outcrop expression and, in some 

of the more extensive outcrop areas, small 

streams have eroded the soft clay shale to 

produce a badland-type of topography. The 

surface slopes of outcrops are steepest 

(more than 12 percent) in the area of the Blue 

Hills and usually range from 7 to 12 percent 

elsewhere in the county.

3. Codell sandstone member of the 

Carlile shale. --The Codell sandstone member, although generally very thin, can almost 

always be identified at the contact of the 

Carlile shale and the overlying Fort Hays 

limestone member of the Niobrara formation. 

The thickness of the Codell varies (greatly) 

within short distances. Landes ll/ reports 

that it is 42 inches thick at the north end of 

the Blue Hills; in other places in the county, 

however, it is less than a foot and its average 

is probably about 2 feet. The Codell is a finegrained sandstone or siltstone and contains a 

moderately high percentage of clay. It is 

usually yellow brown, but some exposures 

more heavily stained with iron oxide are red 

brown.

Representative Measured Sections

1. The outcrop of the basal part of the 

Fairport chalky shale member was measured in a road cut in the NW^SW^sec. 21, T. 7 

S. , R. 7 W. as follows:

Feet

Sanborn formation: Gray-brown silt; abundant lime nodules in lower part .... 7*

Fairport chalky shale member of the 

Carlile shale:

Limestone, chalky, soft; massive; 

weathers platy; tan-gray with 

light-brown streak near middle; 

weathers buff; case-hardened. 

Clam shells .........

Bentonite; flaky; mottled orange 

tan and buff .........

Shale, clayey silt, highly calcareous; thin- to very thinbedded; tan; weathers 

cream; iron-oxide stains 

along bedding and fracture 

planes. Fragments of clam 

shells ... . . .......

Limestone, semicrystalline; soft; 

massive; light tan-gray with 

light-brown streak through 

middle part; weathers buff; 

nodular. Clam shells . ( . .

Feet

.3

0.3

1.5

. 2

Shale, silty, calcareous; thinbedded to blocky in middle 

part; tan-gray; weathers 

cream; iron-oxide stains 

along fracture planes. Clam 

shells fairly abundant . . . . .

Limestone, chalky, soft; massive; 

cream, weathers buff; nodular. 

Fragments of clam shells . . .

Shale, silty, calcareous; thinbedded; tan-gray; weathers 

cream. Fragments of clam 

shells ........ . . . .

1.4 

.2

0.6

Hop. cit.. p. 19.

Total thickness present (underlain by 

Pfeifer shale member of the Greenhorn limestone) ........... 4. 5

2. The following section is representative 

of the Codell sandstone and Blue Hill shale mem 

bers of the Carlile shale. It was measured in a 

cut bank along a tributary of Carr Creek in the 

sec. 34, T. 8 S. , R. 10 W. :

Feet

Fort Hays limestone member of the

Niobrara formation: ......... 35-

Carlile shale:

Codell sandstone member (0. 5 foot thick) 

Sandstone, fine-grained; gray and 

reddish-brown; weathers reddish 

brown ............. .5

Blue Hill shale member (23- feet exposed) 

Shale, clayey but some interbedded 

silty zones; noncalcareous; 

thin-bedded to very thin-bedded; 

dark blue-gray; weathers light 

blue gray; numerous calcareous concretions; veins of 

calcium carbonate in some 

fractures; fracture surfaces 

commonly iron-stained ....

Base covered. 

Thickness

The total thickness of the Carlile shale 

is about 302 feet. The average thicknesses of 

its members are: Fairport chalky shale 

member, 100 feet; Blue Hill shale member, 

200 feet; and Codell sandstone member, 2 

feet. The thickest and most conspicuous 

outcrops are those of thr Blue Hill.

Construction Materials

Construction materials from'the Carlile shale in Mitchell County are road metal 

and fill material.

Niobrara Formation 

Areal Distribution

The uppermost formation of Cretaceous 

age exposed in Mitchell County, the Niobrara,

23t

14
, j .mCjrnbers, the Fqs^t Hays , 

"lime stone '"member (the lower member) and,. 

the Smoky Hill chalk member (the ui per memb.e.r^.^See |ig^ 4. }, However, pnljf. the Fort Hays 

s.,cpu|ity,,.and only, in the area 

''rm3^e cap

^ pi, 

the', higher

e.- w^sternm.0st 1 pajrt qf the county, 

bu, *if so, is concealed beneath the younger. 

Sanborn formation.

1,)

of Jhe

^ ; .ijif thick layers of, 

chalky limestone separated by thin parting^ , 

of chalky shale. The beds of limestone are 

massive althou^h.sopne of thein* b,ecoiji?.platy , 

when weathered. -The Tock-is usually crreamcolpr^d jii|4,;^ea^ie^s. to.spi?ie shade. of .gray.

f

he,il,»j oJT^^^,\ftn^Cjoy ster s a r e f pund rin ,it , _ . 

ut'not,ijit^e,ltfeundaia,c,e.thgit.liiey pccur. in ttie 

unde.rly.pg jf.gr J^tions, .of Cretaceous age .- The 

i aver age 2. 5 feet in thickr :

The partings of shale are only about 

0. 1 foot thick. The shale has a tendency to b« 

platy, is always chalky, and its color is'usuqr,

Hays limestone member typiAajly. wjeatheaj me 

chanically to produce a "shattered" zone. The 

shattered fragments of liinestoae are 5 or 6 

inches long, angular, and irregularly disc

'

t s . Out4rjops,of tiMr FiajstHay* limestone member form bold escarpments generally -from- 35; ' 

to 40 feet high. The total thickness of the member is estimated,KOB.th«--t>asiB of a topographic 

map published by i^e United States Geological 

Survey, to be about 50 feet. . ." , f

Representative Measured Sectijon ' i

!;: :i >>-E,-t^ ^,'i i.. -v - ' i ; - -: - :

.Tike .foliowi*g sefction.; of tftes Fort-Hays 

limestone member; of-the NiobPara formation i£ 

the uppen-parl; t>f that which was cited<i£©r-tiie 

Codeli sandstone and Blue Htli shale members 

of the;jCarliLe^siial*i it is thus *Jcposed in the' 

bankiof;* tributapy^to^Ca^r-Creek in ^

sFeet

Fort Hays limestone member of ttte 

Niobrara formation:

Limestone, chalky; "shattered"

f s0n<?j c-reaas; ^weat&e^s-gray,

> i Fo;S siL dairts amd«oyster s v ,

" Limestpn^: "'

-.1-.' .'-,

r~T >~'^"T^j~ ~ "~' ^^" "i * * ~ I"* 7Y~r * ^""vT", """^"^i 1-^- ^r - ' "-

." ,Iying beds' pf jUimestpne tar,e.. 

' / simUa^to;^® lj^i>--- tl>Jl

IShale; tins a.iyi.tjhe. under-',!,1" ...._ 

"', tying fee^s'o| atwU'er are...r , r , - ; ...

-yjj-r.l -i ' x- -j.t - L - J-Q]{ sW^B ;' ? i

Shale

^ Limestone ,, ,., . .*..*. ., ,r .. .-, 

'Shale . . .' '. . . ...

Limestone .........

Shale ....-.;;;..,*, ... ..--,?. ..,.-: .v

s Ljimeatonpr L. ^ r. -*,-*.,« ,.j,, ; j V.,' £, ; i 

.'. t$^ale.;'! ,, i; ^^,.-;,,_.',, «, : .t,,r,«';,.

Feet

1.2

.1 

2,4

.1 

2.3

.1 

1.8

. 1 

1.4

,3

.3

o^-t H%ysilim«s tone j 

about 50 feet.

th« 

estimated to be

f f orn

mate.?ials-. '^-

Itm^ stone1 *aemand. fill tnaterialJ i

ttf- .= : ! v-.;> -- -J.i; .. -.--.r. /I.'.'-!'

.. SagbprAdFpr-ynajtiOjia. >

v -- i'ln MUchell Couirty, <jie'5*hdst extensive 

\iutcrdps1: are1 those 'of the1 Saribofn'fbrinatitSn 

of Pleistocene and Recent(?) age. (See pi. 1 s 

and fig. 4.) It occurs topographically as: 1 an 

upland phase, a-tea*itie <6l sUt'iap^ing \&.& inter stre'am; areas,'" and 2 '& 'VkEL-ey Jphase in 

which f-t-is-a df's-cenflnuou^^eiioslt'of silt'along 

the naargms ^of-the ViSley!d-6{|;iffie larger 

streams aAtf fiietr trtWferies rnaskittg *fhe 

lowet'p'atrt &I T tfee*^all y"wall. "TKe5 upland 

phase 1's 1 w%ll'idis¥fray^Sf iii^eVfe'ry' paxtrbf the 

cauntyf^th-e1 vietilgy ^has^4¥: e^sp'etially^^ciafAspicRi^e* eitst ^f ^Kit ant aldng; tne 

north side of the lower part of tiie'Valiey oiE 

Salt Creek. The valley phase is never so extfettsive 'along tfce" i^uttx'Side^b'f ^a: valley as it 

is^along m« ttortti :«t4iePiBe«a'tfcse' : bfJ t&e similarity 61 thei* litBelogie 'chi!fa t«si'istic's;'- the 

twk p'Kases 'of/th 

6h plate* "

15,
General Description

The Sanborn formation is composed of 

materials deposited by wind (loess), streams, 

slopewash, and through the action of gravity 

(colluvium). Although the formation is subdivided into members in Nebraska and in some 

parts of Kansas, this practice was not followed 

in Mitchell County inasmuch as the materials 

characteristics of the two or more members 

recognized in the county are essentially similar. The treatment of the Sanborn formation 

as arK undivided unit seems adequate to serve 

the purpose of this inventory of construction 

materials.

Although brown in some places, gray is 

the prevailing color in th« Sanborn formation. 

The "A" horizon of the soil profile is darker 

than the underlying horizons and is brown, 

dark brown, or black. Buried ap.il zones occur 

in a few places in the county.

The Sanborn formation is composed predominantly of silt-size particles. The weathering of the silt in the upper part of the formation 

has broken the particles down to clay size; 

thus the upper part of the formation is a 

clayey silt and the lower part is largely composed of silt. Leaching of calcium carbonate 

from the upper horizons of the soil profile, 

through the action of downward-percolating 

subsurface water, causes this part of the formation to be noncalcareous. The calcium carbonate has been re-deposited in the lower 

horizons of the profile either in a disseminated 

stain or as calcareous pipes, concretions, and 

nodules.

A granitic gravelly sand composed predominantly of sand-size particles of quartz and 

feldspar occurs in the basal part of the formation just above the wall of the valley of the 

Solomon River. Exposures of the sand are infrequent and of small extent. They are best 

along the south side of the valley because most 

of the recent erosive activity of the Solomon 

River has been directed against the south valleywall and has removed the valley phase of the 

Sanborn formation which masks the deposits of 

gravelly sand along the north side of the valley. 

The largest deposit is cited in table 1 as sample 

fa 1.

Where the Sanborn formation rests on the 

Carlile shale at the base of the escarpment 

formed by the Fort Hays limestone member of 

the Niobrara formation, its lower part is a 

limestone gravel. The gravel-size particles are 

fragments of the Fort Hays. That they show 

little rounding indicates that they have not been 

transported very far from the bed of limestone 

from which they were derived. The deposits of 

limestone gravel contain a heavy intermixture 

of silt-size particles.

The upland phase of the Sanborn formation 

was deposited by wind, for the most part, and 

is therefore classified as loess. The valley 

phase may represent the dissected remnant of 

an old high-level stream terrace, but it also includes some material deposited by slopewash,

some deposited by the wind, and colluvium 

moved down the valley wall through the action of 

mantle creep.

A phenomenon known as "catstep" erosion is 

displayed on the steeper slopes of the Sanborn 

formation. The catsteps are slump blocks that 

moved down the slope by gravity when saturated 

with water. The blocks are formed by scarps 

from 1 foot to 3 feet high, and the blocks are 

usually from 15 to 20 feet wide.

Surface slopes in the valley phase of the 

formation range from 2 to 5 percent for the 

most part. Those in the upland phases are as 

great as 2 percent in broad interstream areas 

and range from 2 to 5 percent in narrow interstream areas.

Representative Measured Section

The Sanborn formation, as usually exposed in this county, is so homogeneous that no 

section of it was measured. In almost all 

places it is a gray or gray-brown silt, clayey 

and noncalcareous in its upper part, and heavily 

impregnated with secondary calcium carbonate 

in its tower part.

Thickness

The thickness of the Sanborn formation 

ranges from a feather edge to a maximum of 

approximately 30 feet on the crests of some of 

the interstream areas.

Construction Materials

Construction materials from the Sanborn 

formation in Mitchell County are: Aggregate 

for concrete, road metal, mineral filler, and 

fill material.

Terrace Deposits 

Areal Distribution

Terrace deposits of Quaternary age are 

conspicuous in the valleys of the principal 

streams in Mitchell County. (See pi. 1 and 

fig. 4.) Narrow extensions of the terraces extend into the valleys of the larger tributary 

streams. The most extensive terrace is that 

of the Solomon River which ranges in width 

from about a mile, in the western part of the 

county, to almost 4 miles in the eastern part. 

The terrace in the valley of Salt Creek is 

also prominant but its average width is 

only 0. 75 mile. The terraces along smaller 

streams average less than 0. 5 mile wide. The 

surface slope of a terrace deposit is less 

than 2 percent.

General Description

The terrace sediments are composed 

predominantly of tan to light-brown silt-size 

particles intermixed with clay in the upper 

part of a deposit and interbedded with lenses 

of gravel in the lower part. Most of the claysize fraction is probably derived through the 

weathering of silt in the process of soil

16
development. A dark brown or black "A" horivelopment. A dark brown or black "A" horizon is always present at the top of a deposit 

and one or more buried "A" horizons may 

occur within the deposit. The particles of 

gravel usually wellrounded, are interbedded 

as lenses in the lower part of a deposit and 

are fragments of the Dakota sandstone, 

Greenhorn limestone, and Fort Hays limestone member of the Niobrara formation.

Crude columnar structure is exhibited 

in most of the cut banks eroded into this 

formation. The faces of the cuts stand nearly 

vertically. Whereas the upper part of a deposit is noncalcarcous, the lime leached from 

it has been redeposited in the lower part in 

the form of nodules and pipe-like concretions, 

and as a disseminated impregnation.

Representative Measured Section

This section of a terrace deposit was 

measured in a road cut on the south side of 

the Solomon River in the SE&SWj- sec. 32, T. 

7 S., R. 6 W. :

Soil: Silty clay; black 

Terrace deposit:

Feet

1.7

Silt, somewhat clayey, noncalcareous; dark-brown ...... 1.3

Silt; blocky; light-brown; abundant 

thin streaks of calcium carbonate 

and some small pipe-like concretions of the same material; 

stands in vertical bank and exhibits crude columnar structure . . 4. 3

Silt; somewhat blocky; tan; small 

lens of local gravel in middle 

part; numerous small nodules 

of calcium carbonate; stands 

in vertical bank and exhibits 

crude columnar structure .... 4*

Total thickness exposed (base covered) 9. 6- 

Thickness

The terrace along the Solomon River 

stands from 25 to 30 feet above the level of the 

river. The heights of other terraces in the 

county are 20 feet or less above stream level. 

In the absence of test-hole data, it was impossible to determine the full thickness of the terrace deposits.

Construction Materials

Construction materials from terrace deposits in Mitchell County are mineral filler and 

fill material.

Alluvium 

Areal Distribution

The deposits formed by streams in their 

present gradational cycles are mapped as alluvium. (See pi. 1 and fig. 4.) They constitute

the most recent geologic formation in the county and are being laid down by present-day 

streams. Alluvium is defined in this report as 

the material which underlies the present floodplain of a stream. The floodplain is the area adjacent to the stream channel that is covered by 

water during normal flood stage; its surface 

slope is less than 2 percent. The terrace deposits are composed of alluvium laid down by 

these same streams flowing at higher levels in 

earlier geologic time.

Alluvium is mapped only along the Solomon 

River. Deposits of it are also present in the valleys of Salt Creek and some of the larger tributary streams but could not be shown because 

the map is on too small a scale. The alluvium in 

the valley of the Solomon River averages 0. 3 

mile in width.

General Description

The alluvium of the Solomon River is composed of clay and silt and interbedded lenses of 

local gravel and gravelly sand. Gravel bars are 

quite numerous in the channel of the Solomon 

River, as in the channels of other -streams in the 

county. The particles of gravel are fragments of 

the Cretaceous formations which crop out in the 

watershed of the stream. They include waterworn fragments of the Fort Hays limestone 

member of the Niobrara formation, concretions and clay balls eroded from the Carlile 

shale r the limestones in the Greenhorn limestone, and the Dakota sandstone that is along 

the Solomon River in the eastern part of the 

county and along Salt Creek in the south-central part.

Representative Measured Section

The alluvium shows so little relief that 

a representative section could not be measured.

Thickness

The alluvial deposits are undoubtedly 

thickest along the Solomon River and are estimated to be about 30 feet thick. Similar 

deposits along other streams are thought to 

be no more than 20 feet thick.

Construction Materials

Construction materials from alluvium in 

Mitchell County are: Aggregate for concrete, 

road metal, and fill material.

INVENTORY OF CONSTRUCTION MATERIALS 

General

The objectives of this inventory of construction materials in Mi'tchell County are to 

define the construction materials as they are 

classified in this report and to relate the materials to the map units in which they occur.

Whenever available, laboratory-test 

data have been introduced into the report to 

aid the reader in his evaluation of the materi17
als. The information given in table 1 is based 

on standard testing procedures of the American Association of State Highway Officials 12/ 

and the State Highway Commission of Kansas. 13/ It is expected that prospects listed 

in this report will be proved by subsequent 

augering, drilling, or test pitting and that the 

materials themselves will be subjected to 

laboratory testing prior to production for specific uses.

Although numerous prospect pits and 

quarries were located in the field, no attempt 

was made to complete an exhaustive survey of 

all possible sources. If the construction materials that are available in Mitchell County can be 

related to the geologic formations mapped on 

plate 1, then the use of that map will aid the 

field man in his search for the materials needed 

in a construction project. It will eliminate the 

non-productive areas from the search and, at 

the same time, will indicate the areas in which 

the needed materials are most likely to occur.

Aggregate For Concrete

Engineering and GeoloRJc Characteristics

Aggregate for concrete is classified as 

fine aggregate and mixed aggregate in table 1 

and on plate 1. In this report the distinction is 

an arbitrary one based on the percentage of 

material retained on a standard No. 4 sieve. 

The portion of a sample retained on that sieve 

is designated as the coarse fraction. The material is classified as a mixed aggregate if the 

coarse fraction is 5 percent or more by weight 

of the whole sample, and as a fine aggregate if 

the coarse fraction is less than 5 percent. Fine 

and mixed aggregate will be considered together because of the standard practice of 

bringing the grading to specifications by sweetening or screening.

The materials reported in this and other 

classifications are exposed at the surface or are 

under unconsolidated overburden sufficiently 

thin that they may be economically developed. 

Because of the added expense in the removal of 

the overburden, deposits of sand and gravel 

overlain by thick or consolidated beds usually 

are not included, nor are relatively inaccessible deposits.

Stratigraphic Sources and Performance Characteristics

Two of the geologic formations mapped on 

plate 1 are actual or potential sources of aggregate for concrete. They are the Sanborn formation and alluvium.

12 The American Association of State Highway Officials, 

Standard specifications for highway materials and methods 

of sampling and testing, pt. 2, 5th ed., 1947. Absorption, 

PP. 251-252, Compressive strength, pp. 257-258, Deval 

abrasion, pp. 235-236. Liquid limit, pp. 198-201. Los 

Angeles abrasion, pp. 237-239, Plasticity index, pp. 202- 

204. Specific gravity, pp. 249-250, Toughness, pp. 240- 

241. Weight per cubic foot, pp. 253-254.

13 State Highway Connission of Kansas, Standard specifications for State road and bridge construction, 1945. 

Gradation factor, p. 16, Sieve analysis, pp. 333-334, 

Soundness, pp. 335-336.

1. Sanborn formation. One sample of 

fine aggregate (fa 1) was obtained from the 

Sanborn formation. (See table 1.) The material 

is a fine-grained sand composed largely of 

quartz, subordinately of particles of feldspar, 

and occasional particles of opal and chalcedony. 

Opal and chalcedony are not present in injurious 

amounts. The material contains only a moderate 

amount of wash, it is clear in the colorimeter 

test, but its compressive strength ratio after 3 

days is 0. 83. The deposit from which this material was sampled is in the basal part of the 

Sanborn formation just above the south wall of 

the valley of the Solomon River. Other similar 

deposits are undoubtedly along the south side of 

the river.

2t Alluvium. Five samples (ma 1, ma 2, 

ma 3, ma 4, and ma 5) were collected from the 

alluvium of the Solomon River by the State 

Highway Commission in a State-wide .sampling 

program carried out in 1932. The samples were 

obtained from gravel bars in the stream bed. 

The gravel-size particles are fragments of 

limestones cropping out in the watershed of 

the Solomon River; the band-size particles are 

predominantly fragments of quartz and feldspar. The gradation factor of the samples 

ranges from a minimum of 3. 08 to a maximum 

of 3. 84; the amount of wash ranges from 1 to 

3 percent. The colorimeter test shows that 

there is a small to moderate amount of organic material intermixed with the alluvium. 

Compressive-strength ratios are all above 

unity, and the loss through wear is uniformly 

3 percent.

The alluvium of the Solomon River is the 

most important source of aggregate for concrete in the county. The alluvial deposits of 

other streams are composed predominantly of 

silt-size particles. Lenses of gravel and 

sandy gravel are included in the terrace deposits but lie at such depths below the surface 

that they cannot be developed economically.

Road Metal 

Engineering and Geologic Characteristics

Road metal, known also as surfacing 

material, crushed stone, and aggregate is 

defined in this report as any material that 

may be applied to a road to improve the performance characteristics of that road. The 

following materials are available in Mitchell 

County for use as road metal.

1. Aggregate for concrete. (Table 1).

2. Indurated rocks. Indurated rocks 

available in Mitchell County for use as road 

metal are (a) chalky limestone, a compact, 

massive layer of calcareous material ranging 

from soft to moderately hard; (b) shale, a 

very thin-bedded to massive layer composed 

of clay- or silt-size particles, or both; (c) 

sandstone, a layered rock composed of sandsize particles of quartz cemented by porespace deposits of calcium carbonate, silica, 

iron oxide, clay, or varying combinations of
these. The materials included here under indurated rocks are listed in table 1 and mapped 

on plate 1 under the more specific designation 

of limestone, shale, and sandstone, because 

in addition to their use as road metal two of 

them, limestone and sandstone, may be used 

as structural stone and riprap.

3. Limestone gravel. A deposit composed of subangular to rounded gravel-size 

fragments of limestone in a matrix of silt-size 

particles is here classified as limestone gravel.

Stratigraphic Sources and Performance Characteristics

1. Sources of aggregate for concrete. The 

materials listed in the section on aggregate 

for concrete have been used in Mitchell County 

as road metal on light-traffic roads or as 

base-course material in roads of the concrete 

or black-top type of construction. Their sources 

and performance characteristics have been discussed under Aggregate for concrete.

2. Indurated rocks.

(a) Dakota sandstone. -- Three samples of 

the Dakota sandstone (ss 1, ss 2, and ss 3) were 

collected and submitted to the Road Materials 

Laboratory of the State Highway Commission 

for testing. However, two of them (ss 1 and ss 2) 

slaked so quickly under water that no tests were 

performed. The one sample on which tests were 

completed (ss 3) shows an abrasion loss of 96. 2 

percent and a soundness ratio of 0. 77. So far as 

is known, all of the sandstone ledges in the 

Dakota exposed in this county are composed of 

poorly cemented sand grains and are therefore 

easily pulverized. Similar rock has been quarried in other counties in Kansas and, because it 

usually pulverizes during the quarrying operation, it has been used as loose road metal on 

light-traffic roads and as base-course material. 

Large quantities of this material are present in 

the areas mapped on plate 1.

(b) Greenhorn limestone. -- A combined 

sample (sh 2) of the Lincoln limestone and 

Hartland shale members of the Greenhorn limestone was submitted to the testing laboratory as 

material potentially useful in road stabilization. 

Although the results of the test shown in table 1 

do not include the plasticity index of the material, that index is probably moderately high because of the content of clay in these two members 

of the Greenhorn limestone.

Three samples of the Jetmore chalk member were submitted for testing. -- Two (Is 4 and 

Is 5) were collected from the "shell-rock" bed 

and the third (Is 1) was collected from the inter bedded limestones and shales below the 

"shell-rock11 bedr. Successful use of this and 

similar material in the construction of a light 

type of traffic-bound macadam has been observed 

on many roads in north-central Kansas.

From the Pfeifer shale member of the 

Greenhorn limestone one sample (Is 2) of the 

"Fencepost11 limestone bed and another (sh 1) of

the interbedded shales and limestones below the 

"Fencepost11 bed were submitted for laboratory 

testing. The test data shown in table 1 indicate 

that the "Fencepost11 limestone bed is acceptable 

for use in the construction of roads of the traffic - 

bound macadam type; however, because the bed 

is so thin, a sufficient quantity of rock for this 

use probably could not be produced. The interbedded shales and limestones below the "Fencepost" bed are used in north-central Kansas in the 

construction of stabilized roads. This member of 

the Greenhorn limestone crops out extensively in 

the areas mapped as Kg on plate 1.

(c) Carlile shale. --One sample (sh 3) of 

the Fair port chalky shale member was submitted 

to the Road Materials Laboratory but no tests 

were performed on it because it slakes quickly 

when immersed in water. The basal part of this 

member is similar lithologically to the Pfeifer 

shale member of the Greenhorn limestone, and 

is probably acceptable for the same use in 

road stabilization.

(d) Niobrara formation. -- The Fort Hays 

limestone member (see Is 3 in table 1) is 

utilized throughout north-central Kansas as a 

source-of rock'for the construction of trafficbound macadam. The "shattered" zone in this 

member can be removed with a blade but the 

massive ledges must be quarried. Roads constructed of this material give good performance in wet weather but have a tendency to 

"dust" seriously in prolonged dry weather.

3. Sanborn formation. --Numerous 

samples (see table 1) of limestone gravel were 

collected from the Sanborn formation. Where 

used as a road metal, the particles of silt 

size serve as a binder for the gravel-size 

particles of local limestone. This material is 

used extensively as metal on light-traffic 

roads in north-central Kansas.

Mineral Filler 

Engineering and Geologic Characteristics

Material composed predominantly of 

silt-size mineral particles (50 percent or 

more of the material passing the No. 200 

sieve) is classified in this report as mineral 

filler. It has no more than a trace of sticks 

or organic debris,- but may contain minor 

amounts of fine sand or clay. W. E. Gib son 

of the Road Materials Laboratory of the State 

Highway Commission of Kansas states (oral 

communication) that material will qualify 

for mineral filler only if laboratory tests indicate a low coefficient of cementation.

Stratigraphic Sources and Performance 

Characteristics

Two Stratigraphic units were sampled as 

possible sources of material to be used as 

mineral filler; these are: the Sanborn formation and terrace deposits.

1. Sanborn formation. --One sample 

(mf 4) of the Sanborn formation was tested for 

use as mineral filler. The test data show that
its cementation factor is excessive, undoubtedly because of a too-heavy intermixture of 

clay. The deeper zones in the formation contain much less clay and would be productive of 

acceptable mineral filler in those places 

where erosion has removed the surficial zone 

of clayey silt.

2. Terrace deposits. --Of the three 

samples of potential mineral filler obtained 

from terrace deposits (see table 1), only one 

(mf 3) had a coefficient of cementation within 

acceptable limits. This sample was obtained 

by augering and does not include the upper, 

weathered part of a deposit in which the percentage of clay is highest. Presumably, if 

the upper horizons of the soil profile were 

stripped away from the Sanborn formation and 

terrace deposits, the material exposed would 

contain only a negligible percent of clay-size 

particles and thus would have a coefficient of 

cementation within acceptable limits.

Riprap

Engineering and Geologic characteristics. Riprap, as defined in this report, is any 

material suitable for protecting- earthen fills 

from erosion. To be acceptable for this use the 

material must be relatively sound and free from 

cracks and other structural defects or impurities that would cause it to disintegrate through 

abrasion, slaking, or freeze-and-thaw. It is 

desirable that the material be in blocks having 

approximately rectangular faces 7 inches or 

more in width and that the specific gravity be 2 

or higher.

Stratigraphic sources and performance 

characteristics. Three of the geologic formations cropping out in Mitchell County are actual 

or potential sources of rock for use as riprap: 

(1) Dakota sandstone, (2) Greenhorn limestone, 

and (3) the Niobrara formation (Fort Hays 

limestone member).

1. Dakota sandstone. The sandstone of the 

Dakota firmly cemented by pore-space deposits 

of silica (quartzite) or calcium carbonate 

(quartzose sandstone) is acceptable, on the 

basis of field observation in other counties, for 

use as riprap. However, no ledges so cemented 

were found in Mitchell County. An intensive 

search of the area of outcrop of the Dakota 

sandstone mapped on plate 1 would possibly reveal one or more such ledges not discovered in 

this investigation.

2. Greenhorn limestone. Use of the 

"shell-rock" limestone bed of the Jetmore chalk 

member and the "Fencepost" limestone bed of 

the Pfeifer shale member as riprap has been 

observed on a number of small dams in northcentral Kansas. Although the test data shown in 

table 1 indicate that neither of these is highly 

desirable in this use, field observation reveals 

that they perform acceptably when used to protect small structures.

3. Niobrara formation. Blocks of the Fort 

Hays limestone member have been used as 

riprap on several small dams in north-central

Kansas. Inspection reveals that this rock is not 

acceptable for this use inasmuch as it disintegrates within a short time. Its low specific 

gravity and soundness ratio and its high absorption percentage (see Is 3 in table 1) are adequate reasons to explain the failure of the rock.

Structural Stone

Engineering and geologic characteristics. Structural stone, as defined in this report, is any hard, dense, rock material that 

can be qurraied and produced to desired size and 

shape. Materials fulfilling these requirements 

occur in the Greenhorn limestone and the Niobrara formation in Mitchell County.

Stratigraphic sources and performance 

characteristics. 1. Greenhorn limestone. Two 

limestone beds in the Greenhorn limestone are 

used in this and adjacent areas as structural 

stone. The shell-rock limestone bed at the 

top of the Jetmore chalk member has been 

used to a limited extent as structural stone. 

Although acceptable for this use, its appearance is not altogether pleasing. The 

"Fencepost" limestone bed, which marks the 

top of the Pfeifer shale member, is the source 

of most of the structural stone used in Mitchell County. The stone has adequate bearing 

strength, withstands weathering well, and has 

a very pleasing appearance. Many farm 

homes and other farm buildings, city residences, business houses, and municipal buildings have been constructed of it.

2. Niobrara formation. Limited use of 

stone from the Fort Hays limestone member 

in the construction of farm buildings was observed in this county. Although the rock is 

easily produced to desired size and shape, it 

weathers fairly rapidly and, where used close 

to the ground and thus subject to excessive 

moisture, it disintegrates rapidly through 

slaking and the process of freeze-and-thaw.

Calcareous Binder

Engineering and geologic characteristics. To be classified as calcareous binder 

the material must be composed essentially of 

calcium carbonate and must be soft and easily 

pulverized. Two of the geologic formations 

mapped on plate 1 are sources or potential 

sources of calcareous binder: (1) Greenhorn 

limestone and (2) the Niobrara formation.

Stratigraphic sources and performance 

characteristics. 1. Greenhorn limestone. 

The inter bedded chalky limestones and chalky 

shales of the Jetmore chalk and Pfeifer shale 

members of the Greenhorn limestone appear 

to be acceptable for use as calcareous binder. 

The rock is highly calcareous and, for the 

most part, is soft and relatively easy to pulverize.

2. Niobrara formation. The Fort Hays 

limestone member has been accepted by the 

State Highway Commission of Kansas as a 

potential source of material suitable for use 

as calcareous binder. The beds of chalky
limestone are soft, easily pulverized, and 

free from deleterious substances. However, 

this source of calcareous binder is available 

only in the Blue Hills area in the southwest 

part of the county, whereas far greater 

quantities of binder may be obtained from the 

much more extensive outcrops of the Jetmore 

chalk and Pfeifer shale members of the 

Greenhorn limestone. (See pi. 1.)

Subgrade and Embankment Material

Engineering and geologic characteristics. --This definition of subgrade and embankment material is adapted from the specifications compiled for the American 

Association of State Highway Officials. 14/ 

Suitable geologic materials shown as "fill material" in fig. 4 and in sections on outcropping 

stratigraphic units) for this kind of construction 

are (1) Fine-granular unconsolidated sediments, 

including soil, of which 50 percent or more pass 

through a No. ZOO sieve; (2) coarse-granular 

unconsolidated sediments and broken or crushed 

consolidated rocks, of which at least 65 percent 

by weight is retained on a No. 200 sieve; (3) 

broken or crushed rock.

Stratigraphic sources and performance 

characteristics. All of the materials listed 

above are available in Mitchell County for the 

construction of subgrades and embankments and 

may be the product of excavation along the alignment of the structure, or they can be obtained 

from adjacent areas. The geologic formations in 

which these materials occur are:

1. Fine-granular sediments. The Sanborn 

formation and terrace deposits contain almost 

unlimited quantities of silt or clayey silt. The 

extensive outcrops of these formations are 

mapped on plate 1 and indicate the almost universal availability of the material over the 

county.___

14 Am. Assoc. State Highway Officials, Highway materials, pt. 1, Specifications, pp. 37 and 38, 1937.

2. Coarse-granular sediments. A very 

small quantity of sand and gravel is available 

for use in the construction of subgrades and embankments. The two sources are the basal part 

of the Sanborn formation and the alluvium of the 

Solomon River. It is possible that the more extensive deposits of limestone gravel which occur 

in the basal part of the Sanborn formation might 

also prove acceptable for this use.

3. Broken or crushed rock. The formations of Cretaceous age are the only potential or 

actual sources of broken or crushed rock in 

Mitchell County.

Dakota sandstone. The beds of sandstone 

in this formation are easily pulverized and 

might produce material acceptable for some 

types of subgrades or embankments.

Graneros shale. The bentonitic clay shales 

of the Graneros exhibit such low bearing strength 

that it is doubtful that they would be acceptable 

for use in the construction of a subgrade or embankment.

Greenhorn limestone. The bearing 

strength of material obtained from the Lincoln 

limestone and Hartland shale members of 

this formation probably is low; the strength of 

the material obtained from the Jetmore chalk and 

Pfeifer shale members is undoubtedly appreciably 

higher.

Carlile shale. Except for the Codell sandstone member and the lower part of the Fairport 

chalky shale member, the Carlile shale is composed predominantly of clay.

Niobrara formation. Lroken or crushed 

rock from the Fort Hays limestone member 

apparently is acceptable for use in the construction of subgrades or embankments but if 

the environment in which it is used is one of 

a high moisture content, its acceptability will 

be doubtful.

21 INT.-CUP. SEC., WASH., D.C.MSdM
Southeastern Mitchell County EXPLANATION

R7 W 98° 00'

Drafted by R. M. Soelter, C. E. Grieshaber 

and V. L. Stallbaurner.

Base adapted from map prepared by 

State Highway Commission of Kansas.

Drainage from aerial photographs provided 

by U. S. Department of Agriculture.

CIRCULAR 106 PLATE I

MAP OF MITCHELL COUNTY, KANSAS

Showing Construction Material Sources and Geology

1950

Scale

0 4 miles

R 6 W

Geology by W B. Johnson and D. W Bergman

United States Department of the Interior 

Geological Survey

and

State Highway Commission of Kansas 

Geological Department

c

<D 

O 

<D

cr

<D

a 

a

D

Alluvium

(Clay and silt Interbedded with lenses of local gravel 

and granitic gravelly sand. Source or potential source 

of- aggregate, road metal, mineral filler.)

Terrace deposits ^

(Tan or light brown silt, clayey near surface and lenses 

of local gravel in lower part. Source or potential 

source of: mineral filler, fill material.)

Sanborn formation

(Gray or brown silt, clayey near surface and lenses oi 

limestone gravel and granitic gravelly sand in basal 

part. Source or potential source of: aggregate, road 

metal, mineral filler, fill material.)

Fort Hays limestone member 

of the Niobrara formation

(ThicH beds of massive, cream-colored chalky limestone 

separated by thin partings of chalky shale-, shattered zone below fop; forms escarpment. Source or 

potential source of: road metal, structural stone, fill 

material, calcareous binder.)

Carlile shale

(Thin zone of red-brown sandstone at top; upper part 

blue-gray noncalcareous clay shale with zones of 

septarian concretions and selenlte crystals', lower part 

orange-gray chalky shale interbedded with chalky limestone near base} forms local areas of badland topography. Source or potential source of: road metal, fill 

material.)

Greenhorn limestone

(Gray, orange-gray, and dark gray shales interbedded with 

thin layers of tan-gray or brown chalky or crystalline 

limestone and thin seams of bentonite i includes "Fence - 

post" and "s heJI-rock" beds which forms hillside benches. 

Source or potential source of: road metal, structural 

stone, riprap, calcareous binder, fill material.)

Graneros shale

(Thin-bedded blue-gray noncalcareous clay shale with 

interbedded seams of bentonite and lenses of redbrown sandstone* Not a source of material.)

Dakota sandstone

(Thick layer of massive cross-bedded soft gray-orange 

to red-brown sandstone underlain by varl-colored noncalcareous sitty shale} forms hillside bench. Source 

or potential source of: road metal, fill material.)

^^Geologic boundary 

fa Fine aggregate

ma Mixed aggregate ls L'mestone 

Ig Limestone gravel . sh 5halje 

rnf Mineral filler ss Sandstone

/s Inclined letters indicate materials not listed

in Table I. 

Is 2 Vertical letters indicate materials listed in

Table I and their sample number. 

1.0 Quantity of material available (in units of

IO,OOO cubic yards).

Operated pit or quarry

Prospect pit or quarry

Township corner

City

Federal (US) highway

Slate highway

Other roads, all classes

Railway

Section line

Stream, permanent

Stream, intermittent

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Overlap
Southwestern Mitchell County

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Hartland shale members

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CD 

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Rounded pebbles oflocal limestone and sansize quartzgrains insltmatrix.

ro iDOl

60739

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Red-brown togray, somewhat calcified, 

clayey silt.

CD 01

b

roUl

0 

9

60740

Cementation factor too high.

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ro

UlQ

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o a.Terroce deposit

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Gray-tan siltand fiesand; friable-, slightly 

colcareous.

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Terrace deposit

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Dark-brown totan,very colcareous siltand 

clay. 

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$6O745

Cementation factor too high.

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Light-gray, somewhat calcareous, clayey silt.

CO

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60744

Cementation factor too high.

Mixed aggregate

3 o

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Alluviumco

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ro -JIDto-Clean, siliceous sand-gravel containing some hard limestone pebbles.

w 

rou>20385

Compressive strength: 7days,165; 28125.Wear, 3percent. 

Sand bar inSolomon River.

3 o

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Olto

Ol

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Clean, siliceous sand-gravel containing some 

limestone pebbles.

Ulen

CDUl -f20388

Compressive strength: 7days,l72;28 days,l25. Wear, 3percent. 

Sand bar inSolomon River.

0 

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Clean, siliceous sand-gravel containing some 

hard limestone pebbles.

01

£

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Ul

ro 

OOJ (0

Compressive strength: 7days,138; 2125.Wear, 3percent. 

Sand bar inSolomon River.

3 a

l\3

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Alluvium

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9

OJ

ro

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£

CDro

-xj

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Clean, siliceous sand-gravel containing some 

hard limestone pebbles.

01(B

3u>-f

20384

Compressive strength: 7days,155; 28125.Wear, 3percent. 

Sand barin North Frk Solomon River.

3QZ

m

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AlluviumU)

0 

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roO

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10

10 

CO-Clean, siliceous sand-gravel containing some limestone pebbles.

01 

CD^

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20387

Compressive strength-. 7days,175; 28125:Wear, 3percent. 

Sand bar inSolomon River.

Fine 

ogg.

Q

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mU)

m

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ro 0 *0 0 0

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roo 

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0-xO

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Percentage composition: quartz, 90;feldspar, 

10; opal and chalcedony, trace.

O en

roOl

-xj

X0enb OO CD 

OJ

O

60743

Opal andchlcedony not present ininjurious amounts.

Classification of 

the mater ol

Number on plate

/4 fraction

/4 section

Section

Township (S)

Range (W)

Location

Estimated 

quantity of 

mater ol [cubic yards)

Material : 

(feet) t

Overburden i 

(feet) '

Average tli;/-L/v>aec

Accessibility

0 CD

S 1 

i«

3 o

S i "* o 

o'

3

Authority for 

test dato 2

Dote of test

Percent on 

3/4 inch

Percent on 

3/8 inch

Percent on 

No. 4

Percent on 

No. 16

Percent on 

No. 100

Percent passed No. 200 (wash)

CO5' CD 

Oo_ <5"

Ul

o

CD 

Ul O

T£ 

5'g^31 

(D

3

0

5T 5'

Weight per 

cubic foot (dry!

Specific gravity 

(dry)

Gradation 

factor

1 

day

3 

days

^.-o

±52°

ota <e. 3 

355

Los Angeles 

percent loss

Soundness 3 

(25 cycles)

Cementation

Absorption

Color

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><

p

4

La borao cr Q1>< Ja. aQ

3) CD

3 

o

jr

U)

D

cr

O C

: 3

0 .

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