Insoluble Residues of Some Paleozoic Formations of Missouri, Their

Preparation, Characteristics and Application

BY

JOHN G. GROHSKOPF AND EARL McCRACKEN

REPORT OF INVESTIGATIONS NO. 10

1949

STATE OF MISSOURI

Department of Business and Administration

DIVISION OF

GEOLOGICAL SURVEY AND WATER RESOURCES

EDWARD L. CLARK, State Geologist

Rolla, Missouri

8664

J.UD~STATE PJllNTtNG CO., JE.PPEkSON CITY, MO.

TABLE OF CONTENTS

Table of Contents

List of lllustrations ..

Abstract

Acknowledgments

Introduction . .

Preparation of the Insoluble Residues from Well Cuttings

Plottin g a nd Description of Residues on Well Logs

Developm ent of a Symbol System for Residues

Descriptions of Residues from Val'ious Paleo-wic Formations

Pennsylvanian System

Mississippian System . , .

Devonian System

Silurian System

Ordovician System .. .

Pre-St. Peter Formations

Canadian

Ozarkian

Upper Cambrian

A l>Plication of Insoluble Residues

Index

( 3)

Page

3

5

7

·· ········ 7

8

9

10

12

14

14

18

23

·· ·· ··· ·· · 25

26

28

29

30

31

32

35.

ILLUSTRATIONS

PLATE

I. Concordance in volume of insoluble residues in wells .

Page

.. . facing 10

II.

1. Percentage block with vials of residues terminations ''.' .........

2. Examination pan and vial

III. Residue symbols (non-elastic)

IV. Residue symbols (non-elastic, continued)

V. Residue symbols (non-elastic, continued)

VI. Residue symbols (elastic)

for percentage de-. .... . .... facing 12

. .... . .. . . facing 12

... facing 14

. following ]4

. . following 14

. . facing 15

VII. Partial log with r esidue symbols at left and thefr descriptions at

VIII.

IX.

x.

XI.

right of column ............ facing 22

l. Silicified Endothyra, Spergen 2. Quartz crystals, Short Creek . 3. Matted siliceous spine masses, Warsaw 4. Quattz crystals, St. Louis . . . . . . . .

1. Pyritized depauperatc fauna, Maquoketa 2. Siliceous ammodiscids, Silurian 3. Coralline chert, Devonian 4. Silicified echinoderm segments, Kimmswick

1. Siliceous brown oolite, Jefferson City 2. Pitted (golf ball) oolite, Cottel' .. 3. Siliceous hexactinellid spicules, De1·by-Doerun 4. Siliceous spicules, Jefferson City

1. Glauconitic (pepper and salt) sandstone, Davis 2. Banded quartz druse, Potosi . .

facing 24 facing 24 facing 24 facing 24

.facing 2G facing 26

.. facing 26 . . . ... facing 26

facing 28 facing 28

. .facing 28 facing 28

.facing 30 .. . facing 30

3. Dolomoldic shale, Bonneterre . . . .. ...... facing 30 4. Dolomoldic chert, Van Buren ... . . facing 30

( 5)

I j

INSOLUBLE RESIDUES OF SOME PALEOZOIC FORMA­TIONS OF MISSOURI, THEIR PREPARATION,

CHARACTERISTICS AND APPLICATION

BY

JOHN G. GROHSKOPF AND EARL McCRACKEN

ABSTRACT

The insoluble residues* of selected formations are described and illustrated, emphasis being given to Mississippian, Ordo­vician, and Cambrian formations. The use of residues in the correlation of sparingly fossiliferous strata is discussed. The manner of preparing, describing, and recording of residues is described in considerable detail. Economic applications of resi- · dues are mentioned. The report is descriptive and makes no at­tempt at regional geologic correlations. It is of primary inter­est to subsurface stratigraphers, although it will serve the field geologist in checking field identifications.

ACKNOWLEDGMENTS

The photographs in this report were taken by Mart P. Schemel. Jack James made measurements of certain residues. Margaret Skillman supplied some mineralogic and petrographic data. Other colleagues and fellow workers, particularly the late C. D. Gleason, Garland Gott, and Mary McCracken nee Hund­hausen, contributed ideas and suggestions which are herewith acknowledged. Walter V. Searight edited the nomenclature of the Pennsylvanian section to conform with the agreement of the Inter-State Conference on Pennsylvanian Classification held at Lawrence, Kansas, May 5-6, 194r+'-'·. All the above-mentioned persons are or have been staff members of the Missouri Geolog-

*The insoluble residues hereinafter referred to are the producls of the s olution of acid soluble fractions of rocks, particularly drill cuttings. Residuum produced by rock "·eathering is recognized as an insoluble residue from the parent rock or rocll.S. How­eYer. as hereinafter used, insoluble residues will refer to the product of acid treatment in the laboratory.

**!-Ioore, R. C., Classification of Pennsylvanian rocks in Iowa, Kansas. Missouri, Xebraska and Xorthern Oklahoma, Amer. Assoc. Petroleum Geologists Bull. vo l. 32. pp. 2011-2041. 1948.

( 7 )

8 Missouri Geological Siwvey and Weiter Resources

ical Survey. The authors express their appreciation to Dr. E. L. Clark, State Geologist, for critical reading of the manuscript and for constructive suggestions incorporated therein.

INTRODUCTION

The extensive interest in the study of insoluble residues, after the publication of McQueen's original paper'.HH>, resulted in an early depletion of available copies. This report has been prepared to meet the increasing demand for information pertinent to residues and specifically to the characteristics of the residues from the various rock formations and members in Missouri.

Most of the sedimentary rock succession in the Ozark Region of southern Missouri consists of Cambro-Ordovician cherty and siliceous dolomites or magnesian limestones whose entire thickness may range from 2,000 to 3,000 feet. Sand­stones are present, but, with the exception of the St. Peter, and because of their erratic character and discontinuity do not con­stitute reliable regional subsurface markers. Cuttings from deep wells that penetrate the above-mentioned sequence are spar­ingly fossiliferous and very similar in composition, texture, and appearance. In the absence of well-defined markers, the identifi­cation and correlation of cuttings have been restricted in the main to use of insoluble residues.

The work of McQueen" laid the groundwork for modern subsurface work in Missouri. Since McQueen's original work, the insoluble residue method has developed into routine practice in the subsurface laboratory of the Missouri Geological Survey, where there are now more than 500,000 residues on file from wells in Missouri and adjoining states. It is common procedure to prepare and examine 30,000 to 50,000 residue samples an­nuaily. Such a volume of work requires a systematic and stand­ardized procedure for speed and efficiency.

The use of insoluble residues for correlation is not confined to the Missouri Geological Survey. The method is used by pe­troleum geologists{'\ by various State Geological Surveys, and

***l.'IIcQucen, H. S., Insoluble residues as a guide in stratlgraphlc studies, Missouri Bur. Geol. and Mines, 5Gth Blenn. Rept. State Geologist. 1929-30, App. J. pp. 102·131. 12 Pl., 1931.

•op. cit. ••Ireland, H. A. and others, Terminology for insoluble residues, Amer. As~o,·.

Petroleum Geologists Bull., vol. 31, pp. 1429-1485, 1947.

Repor t of Investigations No. 10 9

by the U. S. Geological Survey***. The application of insoluble residues to the study of cuttings from mineral prospect holes is now a common practice.

This report presents some advances in techniques and criteria for identification which have evolved since McQueen's original work. This paper is not intended to supplant that publi­cation but to supplement it, so that those interested in insoluble residues may obtain information which is in conformity with present ideas and practice.

PREPARATION OF THE INSOLUBLE RESIDUES FROM WELL CUTTINGS

The standard size of sample fills a shell glass vial 21 by 70 mm. A like amount is bottled as the original or untreated sam­ple. The well number and depth of sample are lettered on gummed paper collars and on the cork. When the available sam­ple is too small to fill the vial, the percentage of sample treated is written on the paper collar, thus allowing computation of the true amount of residue by volume. The sample to be treated is then poured into a 250 cc pyrex beaker or an ordinary glass tumbler, depending on whether the sample is to be heated or allowed to digest in cold acid. The glass containers are numbered with black china pencil as to depth of sample and well number. The numbers are easily removed after being slightly heated and wiped.

The glass containers are placed in wooden trays which have dimensions of 28 by 18 by 2 inches and a bottom of 1/2-inch wire screen. A tray of this size accommodates 60 glasses which ordi­narily represent 300 feet of drill hole. The tray can be set over a sink and the acid poured over the samples from a one-gallon wash bottle similar to those used in most chemical laboratories. When the tray is set over a sink, it is unnecessary to pick up or move the individual glasses; the excess acid merely drains into the sink. Approximately 50 cc of commercial hydrochloric acid diluted to half strength with ordinary tap water is used to treat each sample. The tray and samples are then set on a sand bath, if the rock cuttings are dolomite and rapid digestion is desired.

As the action on limestone is much more vigorous, the ap­plication of acid must be slower to prevent the froth from spilling out of the glass. When effervescence ceases, the sample should be

•••op. cit. p. 1480

10 Missouri Geological Survey and Water Resources

removed from the sand bath, as the liquor tends to become thick and gelatinous and may contain small crystals of gypsum. The latter may be formed by the reaction of the sulphuric acid in commercial hydrochloric acid and the carbonate rocks, or from the reaction of sulfide minerals during the preparation of the residue. If the rocks contain silt or clay, the gelatinous material will adsorb it and form a matt or cake when the residue is finally dried. This matt or cake can be eliminated in part by thoroughly washing and decanting the clay fraction from the finished resi­due before drying it. For complete digestion of limestone samples, two applications of acid will suffice, but dolomites usually require three applications. If silt is present in large amounts it may cover the rock chips and prevent the acid from attacking the rock and so retard digestion. In such instances it is usually more practical to wash the sample and decant the silt about one-half hour after the first acid application. The lime­stone and dolomite are usually digested in from three to five hours without heating. Washing is accomplished by swirling the glass under a nozzle-type single-orifice shower spray which thoroughly disperses the material. After it is washed, the sam­ple should be completely dried on either a sand bath or hot plate. If the samples retain moisture after being bottled and corked, the moisture will remain in the vial and leave a messy insoluble residue. It has been noted at times that samples that have seem­ingly been thoroughly dried have adsorbed moisture from the air in the small time interval between the drying and the placing in the vial. Such adsorption is ascribed to the presence of cal­cium chloride crystals which were formed by the reaction of the various constituents. When this occurs, the residue should again be thoroughly washed in order to dissolve the calcium chloride. At this point, mention is made of the effect of heating samples at high temperatures; it is not uncommon to have green and red shales show a color change because high temperature heating causes a change in the valence of the iron. White cherts, if they contain iron, may change to orange or red under such conditions.

PLOTTING AND DESCRIPTION OF RESIDUES ON WELL LOGS

Mention should be made of the advantage of the percentage by volume method over that of percentage by weight. If large volumes of cable tool well cuttings are prepared and speed is

Miuour1 Geologicol Su rvey R. I. No. 10, Plote 1

CONCORDANCE IN VOLUME OF INSOLUBLE RESIDUES

IN WELLS

z <! 0 <! z <{ (.)

DA TUM: l::l ase of Compton Formation

L og No. 5188 SW, SW, SE. Sec l4 T. 29N.,R.23W., Greene Co.,Mo. L og No. 6049 NW, SW, SE. Secl7 T. 29 N., R. 22 w., Greene Co.,Mo. Log No. 9459 SE, SW, SE . Secl4 T. 29N., R. 22W., Greene Co.,Mo. L ogNo. 5130NE, SE,SW. Sec8 T.Z.9N.,R.20W.,GreeneCo.,Mo.

Warsaw

Keokuk

Burlington

Reeds Spring

Fern Glen

0 Zc:o

"'"' o ­_, .n 3 1~ 30 Gre ne Co.

29 I

28

24 2 3 2 2 21 20

200

150

100

50

Vertt col sc:ole leet

LEGEND

rn No Sample ~ D olomite I@! Shale

~ L imestone liiil Sill • Che_rt

~ Dolomitic Limestone

Report of Investigations No. 10 11

desired, plotting the percentage by volume requires about 17 minutes for 200 samples which ordinarily cover 1,000 feet of drilling. Various drillers wash their samples in different ways, but nevertheless plotting the volumetric percentage gives a pic­ture which is accurate enough for correlation ( Plate I) . Weighing each sample is time consuming and requires the preservation of the clay fractions which mask the characteristic residues. For certain types of investigation, the gravimetric method may well be more satisfactory. Mention should also be made that actual comparison has shown that cable tool cuttings from cherty limestones show a greater volume of insoluble resi­due than do cores or hand samples from the same section of rock. This variance is due to the grinding up of the carbonate rock by the percussion of the bit and also by the loss as fines during the bailing of the samples of the finely powdered car­bonate rock which makes an apparent increase in the chert or other harder substances. This increase is particularly true in very cherty carbonate formations.

After the residues are placed in the vials, they are properly numbered as to well and depth of sample. The microscopist plots and describes the residues on a strip log ordinarily used by oil companies and others. The vials are placed in a wooden block to measure the percentage of residue by volume. The block is ordinary 2 by 4 inch lumber about 19 inches long into which holes of %. -inch diameter are drilled in such a manner that, when the vial is placed therein the top of the vial is flush with the upper edge of the block. The block is planed on one side and the holes are intersected so that the vials of residue are observable. The block is painted with black enamel, and ten equal horizontal divisions are ruled on the front face in white enamel, the ten divisions covering the length of the vial. They are numbered from O at the bottom to 10 at the top; each division thus repre­sents 10 per cent by volume of the full vial which is a standard of 100 per cent (See Figure 1, Plate II). The block described accommodates 12 vials at one filling which usually represents 60 feet of drill hole. Smaller blocks, holding fewer vials, are used in the preparation laboratory for measuring percentages when the amount of original sample is too small to permit using a full vial for making residue.

The microscopist inspects the block and visually determines the percentage of residue in each vial. He then plots on a strip

log the total percentage for each sample in the space for the ap-

12 Missouri Geological Survey and Wate'r Resources

propriate depth. A scale made of celluloid marked with 10 equal divisions for the width of the log column is an aid in plotting the percentage of residue. In plotting the total percentage of resi­due, the right edge of the footage column is used for O per cent and the left edge for 100 per cent. After the microscopist has made an inspection with the binocular microscope, he deter­mines the general type of the residue, i. e., whether it is chert, sand, shale, or other material. When two or more types of resi­due are in one sample, he estimates the relative amount of each by visual inspection and indicates these percentages on the log. After plotting the various percentages of residue, he indicates the type in the appropriate space by means of color.

In samples that contain 10 per cent or less shale residue, there is insufficient space to indicate the shale color by checks of color; the shale percentage space carries no color, and the color of the shale is shown by horizontal colored lines to the left of the footage column on the strip log.

After the residue spaces are colored, the original lithology is indicated by means of color in the appropriate space to the left of the residue percentage.

After the percentage of residue is plotted it is poured into a small tin pan, painted with black enamel, triangular in shape, measuring 5 by 3 inches and with a depth of about one-fourth inch. The tapered end is cut off so that the material after it is examined, can be easily poured back into the vial. The pan will accommodate the length of the vial in the 3-inch dimension and the cork can be set against the tapered end ( Figure 2, Plate II). A wide field stereoscopic binocular microscope with mag­nifications of 12.5 to 15 diameters is used for routine examina­tion.

DEVELOPMENT OF A SYMBOL SYSTEM FOR RESIDUES

Formerly, it was routine procedure to describe the residues to the right of the footage column of the log, as is customary with lithologic descriptions. This method was not satisfactory in that the many types were confused.

At the beginning of detailed subsurface investigations of the pre-St. Peter formations of Missouri (1935-1941), it be­came apparent at the outset that the differentiation, strati­graphic position, and zonal relationships of the many types and forms of residues were very difficult to determine merely by

M ISSOURI GF.OLOG!CAL SURVEY R. J. No. 10, PLATF. IT

~= == -- == == -- == __ . -- == -- ...;. 1- =i== == =1= == == == == == == = ~-------- -L_I· _I~ I I -~§!§!~=-

Fig. 1-I'Crt'entage bloc·k w ith vinls of 1·cs id11es for perc·f'ntage <lete rmination;s.

1-'ig, 2- Exarnin at.ion pan nnrl v ial.

Report of Investigations No. 10 13

written descriptions. It was found that illustrations resembling as closely as possible geometrical patterns such as oolites, dolo­molds, and banding in chert could greatly aid in the immediate correlation of these zones and residue sequences with the same zones in other wells. Because of the aid derived from symbols of these few geometrical patterns of residues, the system has been expanded to include most all common residue types in pre­St. Peter rocks (Plates III, IV, V, VI). In the expansion, it was necessary to symbolize texture, color, minor variations, and combinations. It has not been the custom to assign symbols to a peculiar or new residue upon its first appearance, because many residues are sometimes unrecognized variations of common forms or types. Also, many rare or uncommon types do not occur frequently enough to warrant a symbol. The best work­ing plan is to keep the number of symbols to a practical mini­mum, introducing new symbols for new types which may occur with frequency and develop in importance.

It is not the purpose in this discussion of symbols, to out­line a system to be followed implicitly by others. Rather, it is presented here to show several advantages of this or some other system of recording, in abbreviated form, the mass of residue material which is made available for study or correlation pur­poses by the removal of the obscuring limestone or dolomite. The symbols or abbreviations are made with color pencils and placed on the log just to the left of the footage column; these symbols are also described in india ink to the right of the footage column for preservation (Plate VII). The color of residue, with some minor exceptions, is shown by a colored symbol. A red symbol always indicates heavy minerals or fossil debris. Brown is used for brown residues and blue for blue residues. Orange-colored or red residues may be due to iron staining and are not indi­cated. Orange symbols are used for crystalline quartz or quartz sand. A heliotrope-colored plus sign indicates only sandy chert and does not ref er to the color of the chert. In this system, helio­trope color for the symbol indicates siliceous residues of white or light color.

Except for pyrite, glauconite, and various forms of quartz already listed, all minerals are shown by their chemical formulas in red.

Recently, a classification and terminology for insoluble resi­dues has been proposed by Ireland*, which differs only in minor

•op. cit.

14 Missouri Geological Survey and Water Resources

details from that used by the writers. The symbols herein de­scribed have been used for a number of years by the staff of the Missouri Geological Survey and now appear on thousands of logs.

DESCRIPTIONS OF RESIDUES FROM VARIO US PALEOZOIC FORMATIONS

In this description, the formations are discussed in reverse order to that ordinarily used in geological discussions, but it does not necessarily include the complete sequence. The first formation discussed is the youngest, just as though a set of well cuttings was being described.

PENNSYLVANIAN SYSTEM

The insoluble residue method is used primarily by the Mis­souri Geological Survey for correlating limestones and dolomites. A few of the limestones of the Pennsylvanian give characteristic residues, but the shales of this system are not correlated by the method. Descriptions of residues from these limestones are given below* :

Oread: Residues have been recovered from the Platts­mouth limestone, the thickest member of the Oread formation of lower Shawnee age. The limestone is white to gray and con­tains very numerous fossils among which brachiopods and fusu­lines are abundant. The rock in many places is cherty. Residues in some wells contain tan-white chert, gray fossiliferous chert, and silicified remains of brachiopods and fusulines. Ten to 15 per cent of the rock is siliceous and is retained in the residue. The Plattsmouth is the first (youngest) cherty limestone found in the Pennsylvanian of northern Missouri. The chert most closely resembles that of the Argentine, a much lower horizon, as it occurs in cuttings from drillings in southern Jackson and Cass counties. In general, however, the fusulines are more numerous in the Oread ( Plattsmouth) than in the Argentine.

Stanton: The Stanton formation lies at the top of the Lansing group and is a succession of three limestone members separated by shale. The South Bend limestone, an earthy fos­siliferous member, yields a residue which is commonly less than 20 per cent of the sample. It consists of pale-green shale, quartz,

*Unpublished notes concc1·nlng Pennsylvanian formations by Mrs. Mary McCracken. nee Hundhausen, formerly a subsurface geologist with the Missouri Geological Survey.

. ,

Mluourl Geoloolcol Survey R.I. No. 10, Plott Ill

SYMBOLS USED FOR DESIGNATING INSOLUBLE RESIDUES

NONCLASTIC RESIDUES

CHERTS (MAJOR TYPES)

SM TTTT

,a d

Smooth

Translucent

Ouortzose

F'ine Ouortzose

Dead

DESCRIPTION

Opaque, flinty, dense, brittle

Degree of translucency indicated by length of bar

Vitreous, sparkley, shineyi under high mo9-niflcot ion shows heterooeneous composition mixtura of pyramids, prisms. ond crystal faces of quartz

Fra gile. whispy, granu lar

MTripolit ic11

; chalky; soft~ no luster

MODIFICATIONS IN MAJOR TYPES OF CHERT

(WITH EXAMPLES OF COMBINATIONS WITH MAJOR TYPES OF CHERT)

-f Sandy Sand groins in chert matrix;

~ (SM 'hmooth, sandy; (d') dead, sandy

Banded Bands of different colors; (SM\\) smooth banded chert; not ta be confused with quartz druse

M Motl led Hetero 9eneous color differences; (SMM) smooth mottled chert

r Rough Uneven texture; common In dead cher I (d') obviously not assoc iated with (SM) smoo th or (Tr) translucent chert ... Nadu lor Small irreou lor grains developed in

dead chert (d ... )

Missouri Geo109 icol Survey R, I. No. 10, Plott IV

NONCLASTIC RESIDUE SYMBOLS-CONTINUED

OOLITES

INTERNAL

OOLI TES

OOLITES

STRUCTURES OF OOLITES ARE BEST SHOWN WHERE

ARE IN CHERT MATRIX. OPEN CIRCLES DENOTE

IN CHERT; SOLID CIRCLES DENOTE FREE OOLITES

SYMBOL TYPE DESCRIPTION

0 [QJ

9f @

u @

. .. ' ' 4 '

Oolitic

Oolitic

Rodial Oolites

Concentric Dolites

Oovoid

Sandy Ool i tic

Oolite; Free

Oolite1 Clustered

Oolite; Free; Frosted

Oolite; Clustered; Frosted

Oolites and chetl matrix same color

Oolites ond chert matrix of different colori frame indicating chert matrix, and oollte each in its respect ive color

Radii may or may not converge

Common development shows concentric color differences, best shown in err) translucent chert

Voids in center of oolites; shows incomple te s1licificotion of oolite, best development in (.;l.lf) quortzose oovoidic chert

Sand groins as a nucleus of ooHte, (orange center)

Smooth surface

Smooth surface; in clusters

Drusy surface

Drusy surface; in clusters

DOLOMOLDS

fP

000

VOIDS RESULTING FROM THE SOLUTION OF DOLOMITE RHOMBS IN

CONTACT WITH INSOLUBLE MATERIAL

Finely Porous OutHnes and shapes of voids not distin­guishable with magnification of 12 or 15 diameters

Void of opening opproximotely O.O!IMM

oil Fine Oolomolds

Dolomolds Relative size of chert

size of dolomolds represented by symbol; CSM0

) smooth dolomoldlc

EXCEPT FOR THE USE OF HELIOTROPE FOR WHITE, ALL CHERT

SYMBOLS ARE PLOTTED IN THEIR RESPECTIVE COLOR SHADES

•·

Miuouri Geolo;ic:ol Survey A.I. No. 10. P folt V

NONCLASTIC RESIDUE SYMBOLS-CONTINUED

SYMBOL

Q

X

0

o<==> aD

Jfff

VARIOUS FORMS OF CLEAR QUARTZ

(ORANGE MONGOL #862)

Moss1V! Quartz

Crysrol

Fragments

Euhedral Crystals

Eu hedrol Crysta:s.

Oolo mo l ds

Dru se

DESCRIPTION

No crystal outlines shown with

moc;in i fication of 12 to 15 diameters

Shows pyromids or prism faces of

quartz crystals

Very short prism face

Shows relative dimensions of crystal

Clear quo rt z; nol chert

Fine l y banded quartz

FOSSILS ANO FOSSIL FRAGMENTS

GENUS OR SPECIES UNIDENTIFIED (RED MONGOL #866)

Hexact i nello

Ill Spines; F, ..

Mo!1ed Spine Mosses

Echinoderm Se9ments

Srochiopod Fragments

Ammod iscids

Gastropod fragments

Missouri Gtologlcol Survty R. I. No. 10, Plote Vl

CLASTIC RESIDUE SYMBOLS

SYMBOL

V

Y..

RF

A

r

1111

l'P

SAND

(ORANGE; MONGOL #862)

V1 ry fine·, silt 0.05 mm

Fine )

Medium

Coarse

0.05 mm 10 2 .0 mm

A ngulor

Sub - An9ulor

Rounded and Frost t d

A99 r 1oot 1 1

A99r19ote,~ co l or of cop ind ico1e1

color of included oro ill oceous moteriol

Regenerat e d

SHALE

(P L O T T E D IN I T S C O L O R)

MO S$ive, no d ef inite s tructure

M o s siv, 1 contains pyrite

Bonded, lam inat ed color d1ffer e nc 1 1

Laminae of fine sand and shale

f ine l y porous shale

Lominoe show int e rb t dd1d porosily

Report of Investigations No. 10 15

and chalcedonic chert. The Captain Creek is even more earthy and fossiliferous than the South Bend, and the residue of the Captain Creek is mostly gray shale.

Plattsburg: The Plattsburg formation consists of two limestone members, the Spring Hill at the top and the Merriam at the base, separated by shale. Residues made are presumably of the Spring Hill member. The residue is 10 to 25 per cent of the original samples and consists of siliceous spines, tubes, fossil fragments, some gray to tan fossiliferous chert, and gray shale. In addition, pyrite and traces of sphalerite are common.

krgentine: The Argentine limestone is the most prominent member of the \Vyandotte formation of the Kansas City group. (Previous to May 1947, the member was called Iola by the Mis­souri Geological Survey. ) It is very thick, 50 to 70 feet in northwestern Cass County, but thins rapidly to the north. The limestone is gray, very fossiliferous, and it has some gray shale partings. The residue is 10 to 25 per cent of the original sample and consists of quartz, tan and gray dense fossiliferous chert, and other silicified fossil fragments.

Iola: The main and upper bed of the Iola, the Raytown member, is dark, earthy, and very fossiliferous limestone. In some wells it is a coquina of gray, calcareous fossils. The resi­due is less than 10 per cent of the original sample and consists of silicified and pyritized fossil fragments. Among these, sili­ceous "'worm casts" occur, similar to those in the Compton of Mississippian age.

Cement City: The Cement City limestone member of the Drum formation is gray to tan, rather dense and earthy. The residue is 10 per cent or less of the original sample and consists of gray shale, pyrite, and siliceous "worm casts" similar to those which occur in the Raytown and in the Compton.

Westerville or Block: Two limestones occur between the Cement City and the Winterset. One of these, presumably the Westerville, is gray, shaly, oolitic, and fossiliferous. The bed yields a small residue of gray shale and pyrite. The oolitic por­tion may readily be confused with the underlying Winterset.

Winterset: The Winterset limestone is a member with consistent thickness (20 to 30 feet) in the subsurface of north-

16 Missou1"i Geological Survey and Water Resources

ern and western Missouri. The member is gray and very argil­laceous at the top but grades downward into pure white fos­siliferous limestone. In some wells, white oolites have been noted in the limestone about 15 feet above the base. Oolites are found erratically even within restricted areas.

The Winterset is cherty in the lower 20 feet. The chert is gray in argillaceous limestone but it is tan to white in the non­argillaceous. The residue is 10 to 30 per cent of the original sample and consists of gray to white fossiliferous chert, quartz, silicified fossil fragments, and clay pellets. The argillaceous limestone samples yield a residue of gray shale and silt.

Bethany Falls: The Bethany Falls limestone occurs in wells at a rather consistent thickness of about 20 feet. The rock is a nearly pure, dense lithographic limestone with some partings of apple-green shale. Chert and silica, in contrast with asso­ciated limestone beds, are conspicuously absent. The upper five feet of the member is oolitic in parts of Buchanan, Clinton, and De Kalb counties. Oolites are hollow and are composed of cal­cium carbonate. Below the oolitic zone, the texture is that of lith­ographic limestone. In this characteristic, this rock markedly resembles the lithographic portion of the St. Louis of Mississip­pian age. Residues from the Bethany Falls are very small and are commonly not more than 2 or 3 per cent of the original sam­ple. The residues consist of clay pellets, green shale, and pyrite. In some wells, a trace of chalcedonic chert or a very few silicified brachiopod fragments have been noted.

Hertha: The Hertha consists of two limestone members, a thick upper one, the Sniabar, and the Critzer, a thin lower one. These limestone members are separated by the Mound City shale. The Sniabar member is the limestone noted in well cut­tings and resembles the overlying Bethany Falls in its tan to gray color and dense texture. However, the Sniabar limestone contains more argillaceous material, and fossil fragments are more abundant than in the Bethany Falls. The residue from the Sniabar is 10 per cent or less of the original sample and it con­sists of gray and green shale, clay pellets, and a few silicified fossil fragments.

Altamont: The Altamont formation of Missouri consists of three members which, from the top downward, are the W or-

Repo1·t of Investigations No. 10 17

land limestone, the Lake Neosho shale, and the Amoret* lime­stone. The Amoret member is less persistent than the Worland which is probably the limestone most frequently noted in well cuttings. Cuttings are tan and gray, and are very argillaceous. Fragments of brachiopods and crinoids are found sparingly. The Altamont is important in subsurface stratigraphy, but descriptions of residues are not available.

Pawnee: The Pawnee formation consists of two limestone members, the Laberdie and Myrick Station, and an intervening shale, the Mine Creek member. The Laberdie limestone is the most persistent member and the one most frequently noted in cuttings. The rock is white, dense, fossiliferous limestone. The insoluble residue is distinctive in that silicified corals ( Chaetetes sp.) make up a large portion of the residue. The Myrick Station member is commonly tan, earthy, dense, fos­siliferous limestone. The rock yields but little residue, 10 to 15

· per cent in dilute hydrochloric acid. Siliceous fragments of Clinwcammina sp. and Tetrataxis sp. are not uncommon. In­ternal molds of the last-named foraminifers, which are siliceous and argillaceous, are characteristic of these limestones. In this feature the residues resemble the Fort Scott which lies some­what lower in the Marmaton.

For t Scott: The Fort Scott formation is composed of three members. From the base up, they are the Blackjack Creek limestone, the Little Osage shale, and the Higginsville limestone. The limestone members are dense, gray, earthy, and sparingly fossiliferous. The insoluble residues of the limestone members are 10 to 30 per cent of the original sample. They are com­posed of silt, chert, and gray shale with fossil impressions. Fos­sils are fusulines, the foraminifers Tetrataxis sp. and Clinw­ca11i1nina sp. and fragments of Chaetetes sp. Internal molds of Tetrataxis sp. and Climaca1nmina sp., which are siliceous and argillaceous, are characteristic of the limestones of the Fort Scott.

A1·dmore: The Ardmore is the youngest persistent Chero­kee limestone in the Pennsylvanian over most of the State. It occurs as one bed in many places, but elsewhere three or more

•Greene, F. C .. and Searight, W. V., Revis ion of the classification of the post· Cherokee beds of Missouri: Missouri Geological Survey and , vater Resources, Manu­scrip t 1949. Note tha t the name Amore t is to be defined in a forthcoming paper by Cline, L. M., and Greene, F. C.

18 Missouri Geological Survey and Water Resources

beds of limestone with interbedded shales are included in the formation. The limestone is tan to dark gray and commonly more or less earthy. The residue consists of gray shale, porous shale, fossil imprints in clay, and pyrite. In most places, the residue contains no chert but in area$ near the Ozark Dome, in Lafayette, Henry, and Johnson counties, it contains much gray fossiliferous chert. Fragments of fusulines also occur in cherty sections in the same area.

MISSISSIPPIAN SYSTEM

The following descriptions of residues from the Mississip­pian and other systems do not include those formations which are identified by gross lithology or stratigraphic position.

The limestone formations of the Mississippian are readily correlated by insoluble residues. Many formations, especially those in the lower portion, contain characteristic cherts in excess of 50 per cent. The percentage of residue can be used for rough correlation of these formations and in some restricted areas for the correlation of zones within the various formations ( Plate I) .

Ste. Genevieve: The Ste. Genevieve of eastern Missouri is a dense to finely crystalline, sandy, and oolitic limestone. In the St. Louis area, the total residue is less than 10 per cent and is composed of fine sand, gray and tan shale, quartz crystals, and some pink chert. In this area, the contact with the underlying St. Louis limestone is drawn where (a) the typical lithographic St. Louis limestone appears, or (b) the first appearance of white to gray chert, or ( c) in many wells at a bed of dolomite about 15 to 20 feet thick; these three features occur at a common posi­tion. In the type area of Ste. Genevieve County, the formation contains less sand and a higher percentage of chert which may be pink or blue-gray. Zones may be quite oolitic and the oolites may be completely silicified.

St. Louis: This formation is typically a dense lithographic gray to tan limestone. It may be oolitic in part but not nearly as much so as the Ste. Genevieve or the underlying Spergen. It may inc::lude dolomite beds near the middle of the formation. The residue is ordinarily less than 10 per cent and consists of gray to tan chert, a small amount of tan and gray shale, and some pseudo-oolitic, chalcedonic, quartzose chert in the form of rosettes which are less than 0.35 mm in diameter. "Brown

Report of Investigations No. 10 19

sugary crinoid" columnals similar to those in the Spergen (Salem) limestone occur sparingly in the St. Louis. In St. Louis County the lower 25 to 50 feet of the St. Louis formation yields a residue of euhedral quartz crystals in which the pyramids are separated by a relatively long prism. Measurements of the crystals indicate the average length of the prism is 0.46 mm, whereas the total length is 0.79 mm (Figure 4, Plate VIII). The crystals are ordinarily clear and colorless. The St. Louis-Sper­gen contact is drawn at an increase to about 50 per cent of resi­due which consists of gray speckled chert. In many wells, less than 10 per cent of brown somewhat porous shale is found in the residues immediately above the gray speckled chert. A change in lithology from lithographic limestone to granular argillaceous limestone takes place at this boundary. In northwest Missouri the contact of the St. Louis and Spergen has been drawn above a carmine chert. Associated with this red chert is a small amount of silvery-gray shale, and beekite. The writers use the term beekite for the type of residue which Martin* designated as ooloid.

Spergen: In the St. Louis area, the Spergen (Salem) for­mation ranges from 100 to 135 feet in thickness. It is a tan crystalline limestone, oolitic and cherty in the upper portion, and it may be dolomitic. As was mentioned in the description of the St. Louis formation, the cherty upper portion of the Spergen averages about 50 per cent residue predominately gray and tan speckled chert. The chert zone averages about 50 feet in thick­ness and may actually include some of the St. Louis formation of Englemann**. The top of the chert is an easily recognized marker, an excellent datum for structure maps. Below the chert zone, the percentage of residue is 10 to 15 per cent. The residue below the chert consists of silicified Endothyra ( Figure 1, Plate VIII ), and brown echinoderm segments. These are commonly referred to as "brown sugary" crinoids. The lower part of the formation contains pyritized Glypto-pleura and pappillate pyrite. Thin shales may occur in the Spergen below the chert and above the Warsaw. The residues at the top of the Warsaw in the St. Louis area are marked by fragments of quartz, glau­conitic and siliceous spicules, and pappillate pyrite.

• Martin, Henry Garrett, Insoluble res idue studies of Mississippian limestones in Indiana. Dept. of Cons ervation, State of Indiana, P ub. 101, p. 15, 1931.

• •Englemann, G .. Am. Jour. Sci. , 2d s er. , vol. 3, pp. 119-120, 1847.

20 M'issouri Geological Survey and Water Resou1·ces

Warsaw: The Warsaw as typically developed in eastern Missouri, consists of 50 feet of calcareous gray clay shale with which thin limestones may be interbedded. The upper portion of the shale yields residues of silt, milky quartz, and a matted mass of siliceous or glauconitic spicules ( Figure 3, Plate VIII) . When limestone is found with the shale, chert residues of 15 to 20 per cent may be obtained. The chert is typically smooth and blue­gray mottled, a feature which has been given the unesthetic but very descriptive term, "snotty chert." In eastern Missouri about 50 feet of gray crystalline cherty limestone is beneath the shale. Residues from this limestone average 50 per cent and are pre­dominantly blue-gray fossiliferous chert which in some wells is glauconitic. In some wells, a small shale residue is obtained from the lower Warsaw limestone. The contact with the under­lying Keokuk is drawn on the first appearance of smooth light­colored, almost white, fossiliferous cherts, or rough to mealy white cherts. The contact is glauconitic.

In western Missouri the Warsaw has been identified in outcrops in the Joplin District. Cuttings from wells reveal it to be quite different in character from that in eastern Missouri in that the thick clay shale zone of eastern Missouri is absent and the formation consists of very cherty, crystalline limestone. The chert may be gray-mottled to almost white, and present in many wells is a dark blue-gray chert similar to that in eastern Mis­souri. Near the base, the formation may be slightly shaly and silty. A calcareous oolite (Short Creek) has been arbitrarily taken as the basal member. This ooli te is widespread, easily recognizable, and is a good datum for subsurface mapping. A very glauconitic silt or shale zone, "J" bed of Fowler*, in Okla­homa and Kansas has been assigned as the base; however, this unit has not been definitely recognized in Missouri * *. The Short Creek oolites occur in a dense mouse-gray limestone matrix, the texture of which is similar to that of the adjacent limestones. In many wells, the diagnostic residue indicates the position of this oolite member, even if the oolite is not apparent. This residue consists of euhedral quartz crystals in which the pyramids are separated by a relatively short prism ( Figure 2, Plate VIII). Measurements of the crystals indicate the average length of the

•Fowler, G. M., Lyden, J.P., Gregory, F. E., and Agar, \V. M., Chertification In the Tri-State (Oklahoma-Kansas-Missouri) district (wllh discussion): Am. Tnst. Min. Met. Eng. Trans., vol. l 15, J\'llnlng Geology, p. 110, table l, 1935.

••op. cit.

Report of Investigations No. 10 21

prism is 0.10 mm, whereas the total length is 0.30 mm. The crys­tals are ordinarily tan to brown colored. The pyramids are developed as positive and negative rhombohedrons. One face of the positive rhombohedron is larger than the others in many crystals, giving an appearance of offset. The Short Creek oolite is not common in wells in eastern Missouri; however, Wel­ler*** cites an occurrence in Ste. Genevieve County. Samples from a well near McBride in Perry County just to the north, contain calcareous oolite at what appears to be the same position stratigraphically as that cited by Weller. The residue from this oolitic section in the well consists of euhedral quartz crystals very similar in appearance to those found in the Short Creek of southwestern Missouri.

Keokuk-Bur lington: The aggregate thickness of these two formations is 250 to 300 feet in most of eastern Missouri and a maximum of 200 feet in western Missouri. They are each very cherty, cream, white to brown, crystalline, fossiliferous limestone. The chert content in many wells ranges from 20 to 50 per cent. No satisfactory criteria have been found for sep­arating these formations in the subsurface. The cherts are smooth to rough, white finely porous to tripolitic, and the resi­due may contain casts of crinoids, silicified fossil debris, and glauconite. In eastern Missouri, the Keokuk chert is lighter in color than that of the overlying Warsaw. Approximately 50 feet below the top of the Keokuk occurs a tan-gray mottled chert which in appearance is suggestive of the Grand Falls of south­western Missouri. Where the limestones of the Keokuk-Burling­ton become dolomitic, some of the cherts may be dolomoldic. In western and northern Missouri, many wells penetrate a zone of dolomite, averaging 25 to 50 feet in thickness, in the lower por­tion of the Burlington.

Gr and Falls: The Grand Falls chert is typically developed in the Joplin District where it is known as the "sheet ground" ore horizon and the "hog-chaw flint." The formation may range from 25 to 40 feet in thickness and consists almost entirely of chert. The chert is smooth, tan, cream, mottled, and less fossili­ferous than that from overlying or underlying formations. The tendency of this chert to fracture with very sharp edges has given it the local name of "butcher knife flint." Commonly, the

• • •\Veller, Stuart. and St. Clair, Stuart, Geology of Ste. Geneviev e County, Missou ri , l\Iissouri Bur. Geol. and iun es, vol. 22, 2d ser., p. 185, 1928.

2~ Missouri Geological Survey and Water Resources

Grand Falls is underlaid by the Reeds Spring and appears to be restricted in distribution to southwest Missouri.

Reeds Spring: The Reeds Spring in southwest Missouri is typically a dark-gray to almost black, dense and finely crystal­line, cherty limestone. The chert residue may constitute 50 per cent or more of the sample. This chert is dense, smooth, blue­black, subtranslucent with a waxy luster, and typically contains embedded spicules or spines. Associated with the chert residue are some very dark to almost black silt or shale partings. Some of the chert fragments have a very dark center surrounded by a less dense and somewhat tripolitic lighter band. Much of the chert has been fractured and recemented by white chalcedony. Percussion from the drill shatters this recemented mass, with t~e chalcedony veins being preferred planes of fracturing. The result is that some of the chert fragments possess a straight edge bordered with chalcedony. The distribution of the Reeds Spring seems to be restricted to southwest Missouri, although a few wells in St. Louis County penetrate beds in the Fern Glen that are very similar in appearance.

Fern Glen: The Fern Glen green and red argillaceous limestones underlie the Burlington in most of eastern Missouri. Caramel-colored limestone which produces a chert insoluble residue content of 50 per cent occurs in the upper portion. The chert is characteristically smooth, light tan to white, subtrans­lucent, and waxy. It is quite different from the overlying Burl­ington chert. The lowermost 15 to 20 feet of the Fern Glen is a very argillaceous or silty red limestone which has an insoluble residue of red silt, pyrite, or green shale. Quartz and qu.artzose chert occur in the residue and some of the chert contains em­bedded spicules. Millerite, the hair-like nickel sulphide, is common.

Sedalia: The Sedalia is typically developed in central Missouri where it is an argillaceous dolomite or dolomitic lime­stone, ranging in thickness from 15 to 25 feet. The dolomite is ordinarily dark-brown and crystalline. The insoluble residue consists of 10 per cent or less of the rock mass and is extremely fine sand, silt, and pyrite. In northeast Missouri, the Sedalia ap­pears to be a dark-gray limestone, the residue of which is prin­cjpally quartz fragments and crystals.

/

Ml uour1 GtOIOQ•COI Survey R. l . No. 101 Plote VII

>-I-(.)

2 0 1/)

0:: w lJ.. lJ.. w -,

>< :::> 0 0 iii :::> 0 er

PARTIAL LOG MISSOURI SURVEY WELL NUMBER 9303

THEIR WITH RESIDUE

DESCRIPTIONS SYMBOLS AT RIGHT

AT LEFT AND OF COLUMN

Ool itic chert; finely porous chert Tron51ucent chert Oolitic chert, free siliceous oolites

Q f PPP ,,-000 • 00 ...

Smooth cher I; finely porous cher t SM /PP

SM /PP SM /P 50

SM DO SM OO SM 0 0

Dolomoldic chert •• 1 Ool itic chert

SM OO SM SM

; Oolomoldic chert Rounded and frosted $and

RF l :: ~ 10 0

Smooth chert; Shole

SM /PPP SM/PPP SMfPP;J. SM 0

d /PPP O + d SM f SMiifPP

.. ; finely porous chert

Dolomoldic chert Dead, finely porous chert Oo litic; Sondy; Dead chert F-~-'~-., Smooth cherti Fine sand

Ouortt

f:!,~~,,o -11 ; Fine ly porous shole

Tiny oolit;·s \n chert

SM

RF /PPP

RF :J. Rro••• IIFO • •• RF :I.J NI' SM+ RF SM#

~{&o SM SM SM SM SM SMV

I I

" Quar!zose oolltic chert .

Angular sand Smooth chert; Rounded and frosted sand

Sandy chert; Rounded ond

Oolitic frosted

Smooth Smooth Smooth

Sandy

sandy chert oolitic chert chert

N • Anoular chtrft Rounded

chert son di

.. '

sand

Finely porous chert Quortzose chert Ool itic cher t; Free

Quortzose chtrt Smooth sandy chert

and frosted sand

LEGEND

oolites

- E3 No Somploa Dolomite Chor! Sood Shalo(No Color)

L_ ___ _

Report of Investigations No. 10 23

Chouteau: The Chouteau is typically developed in central Missouri where it attains a thickness of approximately 100 feet. In the main, it is a very dense, dark-gray limestone, very cherty in the upper portion. It also becomes somewhat dolomitic in cer-

. tain areas. The residue from the upper portion ranges from 20 to 50 per cent and consists of dense, slate-gray to blue-gray chert, with a few shale partings which are dark brown to almost black and finely porous. In the lower portion, the limestone is somewhat crinoidal; the residue is 10 per cent and contains shale, pyrite, and silicified "worm casts" which are very similar to those of the Compton of southwest Missouri. In northeast Missouri, glauconite is found in many wells in the basal five feet.

Compton: The Compton crops out in southwest Missouri where it is a dense gray rather pure limestone underlying the Northview shale. Well cuttings show its thickness to range from 10 to 25 feet. The residue is ordinarily 10 per cent or less and consists of silt or shale, lattice-like pyrite, and siliceous "worm casts." The Compton can be traced in the subsurface around the Ozark Uplift through central and eastern Missouri, but is not definitely known in northeastern Missouri. The residue is unique and cannot readily be confused with those from the im­mediately adjacent formations. It contrasts very markedly with the upper Chouteau in central Missouri with which it is coexten­sive into eastern Missouri. The Compton is considered to be the basal member of the Chouteau.

Louisiana: In the type locality the Louisiana limestone is a lithographic tan to gray, pure limestone ranging in thickness from 10 to 50 feet, the average being 10 to 25 feet and rarely as much as 50 feet. It may be an argillaceous limestone or a dolo­mitic limestone. Insoluble residues are ordinarily about 10 per cent and consist of silt, pyrite, and pyritized stem-like objects.

DEVONIAN SYSTEM

Fm·tune: Throughout southwest Missouri non-elastic Devonian was unknown until it was discovered in Barry County. It is composed of black, dense limestone, argillaceous dolomitic limestone, chert, and a basal f erruginous sandstone. The chert can be readily identified in well cuttings; in fact, it was first studied in residues from well cuttings and tentatively identified as Devonian. The chert is dense, light cream to olive buff and

24, Missouri Geological Survey and Water Resoitrces

mottled with citrine drab to olive gray. White spicules are em­bedded in the chert. The Fortune seems to be restricted to an area of about 100 square miles and its maximum thickness is six feet.

Callaway: The Callaway limestone as recognized in cen: tral Missouri is white, crystalline, and cream-colored. Included in the Callaway is the pink crystalline limestone called Mineola by Branson"; the Callaway and Mineola as previously dis­tinguished cannot be separated in the subsurface. The resi­due content ordinarily is less than 10 per cent and may consist of pyrite, green shale, sand grains, brown finely porous shale, and coralline silica. The coralline silica is car amel-colored and appears to be a quartz replacement of coral fragments ( Figure 3, Plate IX). This unit is extremely variable in lithology and may contain some lithographic limestones which resemble those of the Cooper which underlies it. Straw-colored sphalerite is common in the residues. Tiny euhedral quartz crystals with a short prism between the pyramids are found in the residues from many wells. Measurements of these quartz crystals show the average length is 0.70 mm and the prism faces only 0.16 mm.

Cooper: The Cooper is typically developed at the outcrop in Central Missouri where it is a dense to almost lithographic limestone throughout which are disseminated, small irregular calcite masses. The thickness at the outcrop is 20 to 60 feet in West Central Missouri. Insoluble residues are ordinarily less than 10 per cent and consist of rounded and frosted sand grains, pyrite, gray or green shale, and in some wells a low percentage of smooth blue-white chert. To the ·northwest in the Forest City Basin, the thickness in some wells expands to as much as 200 feet. The expanded section contains some dense to finely crystal­line dolomite in the upper portion. The lower 100 feet of this ex­panded section is usually a dense buff dolomite which yields an insoluble residue of from 20 to 40 per cent and consists of rounded and frosted sand, quartzose chert, and quartz. The base of the Devonian ( Cooper?) in extreme northern and north­western Missouri is marked by a relatively pure sandstone, ranging from a few inches to 40 feet in thickness. The sand is similar in appearance to the St. Peter, from which it may have been derived. Where the sandstone is absent or poorly developed,

•Branson, E. B., The Devonian of MissourJ: :Missouri Bur. Geology and Mines. 2d ser., vol. XVII, p. 17, 1922.

MtssouRI GEoLocrcAL SuRVJo:Y

Fir:. 1-SIIIC'ifled Endoll111ro Spergen XlO

Fig. :'!- :\fatted siliceous spine masse;; Warsaw X10

R. I. No. JO. PuTF. VTIT

F'rr.. 2-Quartz cry8tn ls Short r.rP('l, X10

F rr:. 4-Quartz C'rystals St. Louis XTO

Report of Investigations No. 10 25

the base of the Devonian contains sand grains in either a lime­stone or dolomite matrix. Though the base of the Devonian is distinctive and well defined, the top of the formation (Cooper?) and the contact with the overlying Callaway is not well marked and has not been consistently established in the subsurface.

Bailey: A few wells in southeast Missouri penetrate a max­imum thickness of 400 feet of very cherty limestone, ordinarily designated as Bailey. It may, however, include part of the Clear Creek and Grassy Knob of southwest Illinois. In the Missouri subsurface, the cherty section has not been divided into separate, recognizable zones. The chert of the Bailey is light-gray and very porous, so ~uch so that many samples are tripolitic and, when finely ground, resemble siltstone. The residue is 50 to 60 per cent and is predominantly a chert that is glauconitic and dolomoldic where the limestones are dolomitized. The lower 100 feet may be non-cherty dolomite. The presence of spores in both the limestone and chert of this lower zone indicates it is Devon­ian. The contact of the Devonian with the underlying Bain­bridge (Silurian) is marked by a distinctive change in color.

SILURIAN SYSTEM

Bainbridge: The Bainbridge is typically developed in wells in southeast Missouri where it is a very siliceous red lime­stone and attains a thickness of 150 feet. The residues average 40 per cent and consist of red to orange-colored silt and tripolitic silica, which in some wells is slightly micaceous. Siliceous fora­minifera, ammodiscids ( Figure 2, Plate IX), have been found in the lower portion in many wells. It should be noted that when the samples from this portion of the section are being treated for residues, great care must be exercised in decanting the liquids to prevent losing the ammodiscids. These foraminifera have been found in Silurian dolomite from wells in northern Missouri and the Forest City Basin. Others* have noted their occurrence in the Silurian elsewhere. Associated with the foraminifera in many wells are siliceous spicules. In the St. Louis area, the Bain­bridge becomes a crystalline dolomite and loses its red color. The insoluble residues from the dolomite contain dense gray speckled chert to white very quartzose chert, siliceous spicules, and am-

*Ireland, H. A .. Use of Insoluble residues for correlation in Oklahoma, Am. Assoc. Petroleum Geologist Bull.. vol. 20, pp. 1086·1121. 1936. Lee, Wallace, The stratigraphy and structural development of the Forest C!ty Basin in Kansas. Univ. Kansas Bull. 51, p. 47, 1943.

26 Missouri Geological Survey and Water Resou1·ces

modiscid tests. In southeast Missouri, the contact of the Bain­bridge and the Brassfield is marked by glauconite. In north­west Missouri, the Silurian is a vuggy dolomite and contains gray speckled quartzose chert in the lower portion. The Silurian of northwest Missouri contrasts with the overlying Devonian in that the Silurian is not known to contain sand grains.

ORDOVICIAN SYSTEM

Maquoketa: The Maquoketa in the subsurface in eastern Missouri is a gray-green dolomitic shale. In northeast Missouri, the lower portion of the section is very dolomitic; the term "flag­stone" has been applied to this portion of the section on the out­crop. The residue may constitute 25 to 50 per cent and contains finely porous silt or shale, a little pyrite, and dolomoldic shale. Graptolites which are common in the shale are destroyed by the acid and do not appear in the insoluble residues. rrhe Maquoketa is the youngest dolomoldic shale in the Missouri Paleozoic sec­tion. Residues from the lowermost few feet consist of a pyritized depauperate fauna ( Figure 1, Plate IX), which has not been noted in any other formation in Missouri. In southeast Missouri, a sandstone (Thebes) or siltstone averaging 15 feet in thickness has been noted in the middle of the Maquoketa. In northeast Missouri, a few wells have encountered a zone of hematite oolite and red shale in the upper 15 to 25 feet of the Maquoketa. Where the Maquoketa shales are in contact with Devonian shales, the presence of spores is used for the identification of the Devonian.

Ki1nmswick: The Kimmswick formation in southeastern and northeastern Missouri consists in the main of white to gray crystalline limestone. The Kimmswick limestone is very pure and has a very low residue content, 10 per cent or less. The resi­due consists of silicifi.ed brachiopod and echinoderm fragments throughout most of the formation. In the middle portion there is a chert zone through about 15 or 20 feet of interval. This chert may be 25 per cent by volume of the original material, is gray colored, hard and smooth, and contains brown specks. In northeastern Missouri, portions of the Kimmswick become par­tially dolomitized on the west side of the Lincoln Fold.

In the deeper portions of the Forest City Basin, three divi­sions of the Kimmswick may be noted. The upper division is relatively low in insoluble residue content. The dolomite in this division is crystalline, gray to blue-gray and the chert is like-

)hssouRr G£oLocrcAL St.1RYF.,

l·'ig. 1-Pyritlzecl depaupcrate fa una M:l{j\lOkPtn XlO

Ftr.. 3-Coralline chen Devonian X l o

R. r. No. 10, PL.ATE JX

.. . . ' . • o e .•••.•. A, .

. ~ .

• ... ... 0

F'rr.. 2-Sillccous ammodiscid~ Siluri an XJO

Frr.. ,J-Sllicified Echinoderm Regments Kimmswick XlO

Report of Investigations No. 10 27

wise gray to blue-gray in color. Beneath this is a very cherty zone. The chert is smooth, gray, and has black specks dis­tributed through it. This zone is underlaid by a non-cherty, coarsely crystalline, brown to cream colored dolomite. The resi­due from the latter is normally 10 per cent or less and may con­sist of silicified brachiopod fragments and echinoderm segments ( Figure 4, Plate IX) which are composed of brown gr anular silica.

Decorah: The Decorah is typically a dense gray fossili­ferous limestone or dark brown dolomitic limestone interbedded with gray and green shales. Residues average 40 per cent in many wells and may consist of smooth, waxy, dense to tripolitic dark chert with red or cinnamon-colored specks. Silicified brachiopod fragments and echinoderm segments are common in the residues. Green shale is more abundant in the lower part. A metabentonite zone has been used to delineate the base of the Decorah.

Plattin: The Plattin is a dark gray dense limestone which may become dolomitic in northeast Missouri. Ordinarily, the in­soluble residue content is less than 10 per cent and consists of smooth, waxy, and dense dark-gray to almost black chert which may be dolomoldic where the formation becomes dolomitic. A very small amount of dark-brown finely porous shale or silt with fossil imprints is common. Green shale occurs in the lower por­tion in eastern Missouri. Silicified echinoderm segments and brachiopod fragments are ordinarily found in some portion of the formation. Oolitic and conglomeratic limestones mark the base.

Rock Levee: The Plattin and Joachim of eastern Missouri have been zoned with a portion of each assigned to the Rock Levee*.

The Rock Levee includes certain dense limestones which were formerly included in the Plattin and which lie beneath the oolitic and conglomeratic limestone. The Rock Levee also in­cludes certain dolomites which were formerly included in the Upper Joachim formation. The residues from the Rock Levee

*Grohskopf, John G., Zones of Plattin-Joachim of eastern Missouri, Bull. Amer. Assoc. Petroleum Geologists, vol. 32, no. 3, March 1948. Reprinted as Report of Investi­gations, No. 6, by Division of Geological Survey and Water Resources, Rolla, Missouri, 1948.

28 MiBsou1·i Geological Survey and W ate1· Resources

are ordinarily less than 10 per cent and commonly consist of shale with some silicified echinoderm segments which are re­ferred to as "cystids." A small volume of gray to tan dolomoldic chert may be found in the lower portion of the formation. The "cystids" are commonly composed of brown to caramel-colored granular silica. Beneath the "cystid" zone, the residue from.the Rock Levee consists of fine sand and silt, ordinarily less than 10 per cent by volume.

Joachim: The Joachim consists of light-buff, finely granu­lar to crystalline dolomite at the top of which is a thin chert zone. The chert is dense light-gray to almost white and is ordinarily less than 10 per cent by volume. The residues from the upper portion of the Joachim may contain sphalerite, finely porous brown-banded pyritic shale up to 10 per cent in volume, and very fine sand grains. Green shale partings are also found in certain portions of the Joachim. In the upper portion, a zone of silici­fied echinoderm segments is found in many wells. The lower portion contains more and coarser sand than does the upper por­tion.

PRE-ST. PETER FORMATIONS

The Canadian and Ozarkian divisions of Ulrich.,. are used because of their regional residue characteristics.

The following generalizations concerning stratigraphic range of major residue types may be·useful in regional correla­tions and eliminate tiresome repetition in the detailed forma­tional descriptions of pre-St. Peter formations:

(a) Smooth chert is common in the Canadian and upper Ozarkian. This type of chert is rare below the Van Buren for­mation.

(b) Oolites, more often than not, are associated with smooth and quartzose chert. Free oolites and oolites in smooth chert are common in the Canadian and upper Ozarkian. Quartzose oolitic chert and free frosted oolites are found in re­curring zones in the Canadian, rarely in the Ozarkian, and are absent in the Cambrian.

(c) Dolomoldic cherts are abundant in the Canadian and upper Ozarkian and constitute good markers. Dolomoldic chert is rare in the Cambrian.

*Ulrich, E. 0., Revision of the Paleozoic systems: Geol. Soc. America Bull., vol. 22, pp. 627-647, 191 J.

i.VITS$0URI GEOLOGICAL SURVF.Y

F1<: . 1~<;i1iceous brown oolite Jeffer son Cit~- Xl 0

Fie. :'l-S ilic-cous hexac-tinell id ,sp ic-11le:s DC> rhy-DOC'ru n XlO

R 1. No, 10, PLATE X

F ir.. 2-Pittecl (golf ball) oolite Cotter Xl 0

Frc. 4- Si1iceoi1s spicules .J effer"on C' ity X 10

Repo1·t of Investigations No. 10 29

( d) In the pre-St. Peter formations, fine quartzose or granular silica is restricted to the lower Ozarkian and upper part of the Upper Cambrian.

(e) Sand lenses, sandy dolomites, and thin shales are found in the Canadian. Except for the Gunter and the upper Eminence, the Ozarkian has little or no sand. Glauconitic sand­stone is confined entirely to the Cambrian.

CANADIAN

Powell: Intervals referred to the Powell formation, but which may be upper Cotter, are found in the subsurface of east central and southeastern Missouri. Distinguishing residues of the Powell are greenish and white finely porous silica, green shales, and small brown quartzose free oolites. The porous silica shows a large percentage by volume.

Cotter: The Cotter formation is widely distributed in southwestern Missouri and crops out in a band in eastern Mis­souri paralleling the strike of the Ozark uplift. This formation may be divided into three major units: an upper shaly zone with small quantities of tiny quartz masses, a middle cherty oolitic unit containing large pitted free oolites which resemble golf balls (Figure 2, Plate X), and a lower relatively non-cherty unit. Spicules and horseshoe-shaped echinoderm segments are often found in the middle portion of the lower unit.

J efjerson City: The interval assigned to the Jefferson City is 170 feet in eastern Missouri and 225 feet in southwestern Missouri. The residue percentage curve is very consistent throughout the state of Missouri. Smooth oolitic chert makes up the major residue of this formation. The residue at the top is marked by free brown oolites (Figure 1, Plate X). Siliceous spicules ( Figure 4, Plate X) are in the middle portion. The lower 35 to 40 feet of the formation is the "Quarry Ledge" of outcrop and is characterized by a residue of quartz masses.

Roubidoux: The Roubidoux has a brown quartzose oolitic chert zone averaging 25 to 40 feet in thickness at its top. Below this zone, dark smooth oolitic chert may be encountered in cen­tral Missouri, white oolitic smooth chert interbedded with sand­stone in southwestern and south central Missouri, and relatively pure sandstone in eastern Missouri. Sandy chert is prevalent in this formation. Sand zones and sand lenses are discontinuous and are difficult to identify locally as to stratigraphic position.

30 Missouri Geological Survey and Water Resources

OZARKIAN

Gasconade and Van Buren: The Gasconade is divided into two units. The upper Gasconade contains rarely more than ten percent by volume of brown and green quartzose chert. The lower Gasconade, in contrast, has an average of 50 to 60 per cent of white smooth and quartzose oolitic chert which grades down­ward into gray-white smooth oolitic or dark shades of gray or blue chert of the Van Buren formation. Brown oolites in white smooth chert are a characteristic of the Van Buren. Absence of oolites or changes in color are troublesome factors for consistent correlation of the Gasconade-Van Buren contact. Large elliptical or "bean like" free gray oolites and voids showing in­complete silicification of the centers of oolites are excellent identifying characteristics of the Van Buren in central Missouri. In the Van Buren and approximately 30 feet above its base, quartz druse and large dolomolds ( Figure 4, Plate XI) in chert are abundant and constitute a reliable marker zone. A striking feature of the Gasconade-Van Buren formations is the absence of sand grains.

Gunter: The Gunter is a well developed sandstone of ap­proximately 30 feet in west central Missouri. Other areas in Missouri show this interval between Van Buren and Eminence to be a dolomite zone containing traces of green shale, fine porous dolomoldic silica, and variable sized sand grains.

Eniinence: Facies changes present problems in regional correlations of the Eminence formation in extreme western Mis­souri and in Kansas. However, in most of Missouri, fine gran­ular or quartzose chert is the dominant residue. White quartzose oolitic chert is present in the upper portion of this formation. Very thin sand lenses are often found in the upper portion. Druse, similar to that of the Potosi, may occur in the lower por­tion of this formation. Except for the rather large percentage of white oolitic chert in the upper portion, the Eminence forma­tion has a low residue content.

Potosi: In the area of the type locality of the Potosi out­crops in Washington County, Missouri, banded quartz druse (Figure 2, Plate XI) is the outstanding residue feature. In this area residues often show as much as 80 per cent by volume. Very important for Potosi correlations is the zoning of the com­plete Potosi interval, which shows this formation to have zonal

MISSOURI GEOLOGICAL SURVEY

F'1':. 1- G la uconitic ( pep per anrl sn it) sandstone Davis XlO

F"IC:. 3- Dolomoldic shale Bonneterre X l O

R. I. No. 10, PLATE XI

Fie. 2-Banded quartz ,1r11se Potosi XJO

Ftf:. 4- Dolomoldic <'hert Yan Buren XJO

Report of Investigations No. 10 31

sequences of white and brown quartzose dolomolds, brown free quartzose oolites, and crystalline quartz. Fine brown granular silica, similar in texture to the fine gray granular silica of the Eminence, is found throughout the Potosi formation.

A typical development of druse shows layers of quartz bands draped on the walls or sides of cavities in the dolomite. As many as twenty individual bands have been counted per millimeter. The concave or attached surface is dolomoldic; the outer or sur­f ace of growth usually shows quartz pyramids.

UPPER CAMBRIAN

Derby-Doerun: The combined interval of these two forma­tions ranges from 125 to 150 feet in thickness in the region of their type localities. The upper portion has residue character­istics of druse and brown and white quartzose dolomoldic chert, not unlike the Potosi formation. Traces of green shale and clay minerals are common. Glauconitic sand and brown and green shale are found in the lower 40 or 50 feet of these formations. Hexactinellid spicules (Figure 3, Plate X) and echinoderm frag­ments are common in these formations. Regionally, this fossil assemblage seems to be more prevalent in the lower portion which is highly silty.

Davis: The upper portion of this formation has an aver­age of at least 65 per cent fine sand and fine glauconite and shows lamination; this material has the appearance of "salt and pepper" (Figure 1, Plate XI). Shales with less sand content are usually found in the lower portion. Coarse sand with large pellet glauconite are characteristic residues of the basal portion of the formation.

Bonneten·e: The Bonneterre formation in most of the subsurface of Missouri is rather pure dolomite or limestone. The residue content of the upper portion is generally small and consists in the main of pyrite, clay, and shale. In the lower por­tion the residue content increases, with shale and sand becoming the predominant residue material. In restricted areas in south­east Missouri glauconite is also a major portion of the residue. In most wells, the absence of chert is noteworthy. Dolomoldic green shale ( Figure 3, Plate XI) is an excellent marker zone. No generalized description of the Bonneterre residues will ap-

32 Missou1"i Geological Survey and Water Resources

ply for regional correlation. Detailed zoning of the formation by means of residues is possible in restricted areas with closely spaced control wells*.

APPLICATION OF INSOLUBLE RESIDUES

Stratigraphic correlation: The descriptions given indicate the use of insoluble residues in the correlation of carbonate strata. It must be emphasized that it is only rarely that a par­ticular residue alone from a restricted thickness of rocks can be safely used for correlation. Use of residue assemblages is similar to the use of fossil assemblages by paleontologists for correlation. Certain residue assemblages are valuable keys for correlating formations. In the Missouri Paleozoic section, globu­lar or pellet-like glauconite is restricted to the following forma­tions or systems:

Mississippian System Devonian, north central Missouri and southeast Missouri Silurian, Brassfield Cambrian, Davis and Bonneterre

The lack of chert or sand grains may be indicative if not conclusive evidence of age relations in certain areas. The Silurian of the Forest City Basin is non-sandy. The Devonian of the Forest City Basin is commonly sandy, but glauconite is rare.

Various types of siliceous oolites may be restricted to cer­tain zones. Oolitic cherts are rare and almost wanting in the Missouri Paleozoic above the St. Peter sandstone; the few occur­rences noted are in the very oolitic limestones of the Mississip­pian System, such as the Ste. Genevieve or Short Creek. In these formations, the residue assemblage and sequence serves to elim­inate other possibilities. The writers cannot stress too strongly that correlation of well cuttings by insoluble residues involves a thorough knowledge of the type of residues in a particular group of rocks for that area or depositional basin. Also, many residue correlations are dependent upon the sequence, as well as the assemblage.

Ground W ate1·: The Geological Survey answers hundreds of requests each year concerning depth for certain yields of

•James, Jack, Personal communication.

Report of Investigations No. 10 33

water from rock wells. To answer such requests requires a knowledge of the formations which yield ground water, their depth, thickness, lithologic character, and subsurface distribu­tion. The stratigraphic correlations made of well cuttings by the insoluble residue procedures is extremely valuable in such work. In addition to giving information concerning depth of certain aquifers, the Survey is called upon to determine a casing point for wells to be approved by the State Division of Health. The presence of certain cherty zones in the formations, which may influence the casing point, can readily be determined by the insoluble residue method.

Sedimentation: Insoluble residues yield much informa­tion concerning silicification, dolomitization, and facies changes of certain limestones or dolomites; and by permitting the recog­nition of the appearance of different lithologic types which, when traced laterally, become the predominant rock type. In this re­gard the residues have more widespread application for correla­tion when they are restricted to regional basins of deposition.

Mineral Deposits: Small percentages of minerals in sedi­mentary formations are readily noted in insoluble residues. This fact gives some idea of the distribution of such minerals as fluorite, galena, sphalerite, chalcopyrite, millerite, barite, etc., in the geologic column. Such studies may cast some new light upon the origin of ore deposits which are not obviously related to a known source. Also, it will enable zoning the associated forma­tions so that structure and isopach maps may be prepared from drill hole samples.

Insoluble residues serve as a rapid means of determining roughly the purity and suitability of limestones and dolomites for certain purposes. One example may be cited. It was desired to find a dolomitic limestone which was somewhat siliceous, but non-cherty or sandy, for the manufacture of rock wool. A knowl­edge of the silt in the insoluble residues of the Sedalia (Missis­sippian) indicated that it would probably be suitable. Further investigation by making chemical analysis and blowing tests of samples of Sedalia from the outcrop indicated the formation was eminently suitable for manufacture of rock wool, and a plant was erected and put into production at one of the outcrops so tested.

34 Missouri Geological Survey and Water Resources

Other examples are the suitability of certain carbonate rocks for agstone. Insoluble residues in many instances give a rapid though rough idea of suitability. In one instance, a con­tractor opened up his agstone quarry in the "quarry ledge" beds of the Jefferson City formation, chemical analyses of which in­dicated the rock to be sufficiently pure for use as agstone. However, after a few days operation, the contractor complained that the rock caused excessive wear of the hammers in the ham­mer mill. Residue studies showed that the silica, even though lovv as determined by chemical analyses, was in the form of tiny quartz crystals which caused the excessive wear of the hammers. Residue studies will yield much information concerning com­position of carbonate rocks in a rapid and inexpensive manner. The presence of glauconite in certain carbonate formations might well enhance their value as a source of agstone containing potassium, in addition to the usual elements. The presence of chert in limestone may be a determining factor in the economic operation of certain types of quarries.

Field Mapping: During field mapping in the Ozark Re­gion, it is not uncommon to find areas in which outcrops, where present, are rare, or non-continuous. This fact makes tracing of certain beds difficult or even impossible. Sampling of outcrops for residues is common practice in field mapping in the Ozark Region. Such samples, when carefully and systematically taken, can often be identified from the residues. The sample should in­clude any microscopically visible chert, shale, or other insoluble material. An attempt should be made to obtain representative samples. Familiarity with the insoluble residues of the various formations as previously determined is a distinct asset in obtain­ing samples which may be representative or diagnostic. Sample size is ordinarily about the size of a man's fist. The samples are then crushed, but not ground, so that they will pass a 10-mesh screen. Usually three vials of material from hand samples yields a residue comparable to one viaj of well cuttings.

..

INDEX

Abstract Acknowledgments

A

Agstone, determination of quality by residues Altamont formation Ammodiscids, Bainbridge .... . ... . Amoret member, Altamont . .. . ... . Application of insoluble residues .. Ardmore limestone Argentine member, Wyandotte

Bailey formation

B

Bainbridge, contact with Devonian, Bailey . .. .. Bainbridge and Brassfield, contact of, Bainbridge Bainbridge, Forest City Basin Bainbridge formation . . .. . ... ..... . . Bainbridge, St. Louis area Beekite Bethany Falls formation Blackjack Creek member, Fort Scott Bonneterre formation

Callaway formation Canadian System of E. 0. Ulrich Captain Creek member, Stanton

C

Cement City member, Drum ...... . Chaetetes sp. Chert, black specked, Kimmswick . Chert, carmine, St. Louis Chert, cinnamon-colored specked, Decorah Chert, dolomoldic, Bailey Chert, dolomoldic, Van Buren Chert, fine granular or quartzose, Eminence Chert, glauconitic, Bailey . . ......... . Chert, gray speckled, St. Louis ..... . Chert, green quartzose, Gasconade . . . . . . ..... . Chert, oolitic quartzose in pre-St. Peter formations Chert, Plattsmouth, resemblance to Argentine Chert, quartzose oolitic brown, Roubidoux formation Cherts, dolomoldic, Canadian ...... . Cherts, dolomoldic, pre-St. Pete1· Cherts, tripolitic, Keokuk-Burlington Chouteau formation

( 35)

. . .. . . ..

Page

7 7

34 16 25 17 32 17 15

25 25 26 25 25 25 19 16 17 31

24 29 15 15 17 27 19 27 25 30 30 25 19 30 28 14 29 28 28 21 23

36

Clear Creek limestone Climacamniina sp. . . Compton formation Contents, table of . . Cooper formation ..

Index

Cotter formation, three major units of Crinoids, "brown sugary," Spergcn Critzer member, Hertha

Davis formation . .. . ....... . Decorah formation Derby-Doerun formations Devonian, base of, Cooper Devonian System . . Drum formation Druse, banded quartz Druse, development in Potosi

D

E

Echinoderm fragments, Derby-Doerun .. Echinoderm fragments, silicified, Kimmswick Echinoderm segments, Decorah Echinoderm segments, Kimmswick Echinoderm segments, Plattin Echinoderm segments, silicified, Rock Levee Eminence formation Endothyra, silicified, Spergen

F

Fauna, pyritizcd depauperate, Maquoketa Fern Glen formation Field mapping, use of residues in Fort Scott formation Fortune formation Fossil imprints, Plattin

Gasconade formation Glauconite, Bainbridge Glauconite, Bonneterre . . . .. . . . . Glauconite, Chouteau

G

Glauconite, globular or pellet-like, in Missouri Paleozoic section Glauconite, pellet, Davis . . . ......... . Glauconite, "salt and pepper," Davis . . . .. . .. . Glypto-pleui-a, pyritized, Spergen Grand Falls formation Graptolites, Maquoketa Grassy Knob limestone, Bailey Ground water, application of residues in study of Gunter member, Van Buren

Page

25 17 23 3

24 29 19 16

31 27 31 24 23 15 30 31

31 26 27 27 27 28 30 19

26 22 34 17 23 27

30 26 31 23 3~ 31 31 19 21 26 25 32 30

Hertha formation . . .. . . .

Index

H

Hexactinellid spicules, Derby-Doerun . . Higginsville limestone member, Fort Scott

Illustrations, list of . Introduction Iola formation

".T" bed of Fowler, Warsaw Jefferson City formation .Joachim formation ..

Keokuk-Burlington formations Kimmswick, Forest City Basin Kimmswick formation .. Kimmswick, three divisions of

Laberdie member, Pawnee ..... Lake Neosho member, Altamont

I

.T

K

L

Little Osage shale member, Fort Scott Louisiana formation

Maquoketa formation .. Metabentonite zone, Decorah Millerite, Fern Glen ... . Mississippian System Mound City shale member, Hertha Myrick Station member, Pawnee

M

0

Oolite, hematite, Maquoketa . . . ........ . Oolites, brown, Van Buren . . .. .. ... . .. . . . .. .... . . ... . Oolites, centers, incomplete silicification of, Van Buren Oolites, free brown, Jefferson City .... . .... . . Oolites, free frosted, pre-St. Peter .... . . . Oolites, free gray "bean like," Van Buren Oolites, pre-St. Peter ....... . .. . . .. . Oolites, resemblance to golf balls, Cotter Oolitic limestone, Ste. Genevieve Oolitic limestone, St. Louis . . . . . . . . . . ............. .

37

Page

16 31 17

5 8

15

20 29 28

21 26 26 26

17 17 17 23

26 27 22 18 16 17

26 30 30 29 28 30 28

. . . . . . . . . . . 29 18

. . . . . . . . . . 18 Ordovician System .................. . .... . .. . . . . 26

14 . . 28, 30

Oread formation .. ......................... . Ozarkian System of E. 0. Ulrich . . .............. .

38

Pawnee formation

Index

p

Pennsylvanian Classification, Interstate Conference on Pennsylvanian System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........ . Plattin format ion . . . . . . . . . . . . . . . . ... . . .. . .. . Plattsburg formation . . . . . . . .. . . . .. . .. . . . Plattsmouth limestone .. . ... .. . .. . . . Plotting and description of residues on well logs Potosi formation Powell formation .. Preparation of insoluble residues from well cuttings . .. . .. . . . Pre-St. Peter formations Pyrite, lattice-like, Compton . . . . . . .. . .. . . .. . . .. . . .

Page

17 7

14 '2,7 15 14 10 30 29

Pyrite, pappilate, Spergen . . . . . . . .... . .. . .. .... . . ..... . .. . .

9 28 23 19

Q

"Quarry Ledge," Jefferson City Quartz crystals, euhedral, Callaway . . . Quartz crystals, euhedral, Short Creek Quartz crystals, euhedral, St. Louis Quartz crystals, Ste. Genevieve . . Quartz fragments and crystals, Sedalia . . . . . . . . . . . . . . . . . . .. ... . . Quartz, milky, Warsaw . .. . .. . .... . . .. . .. . ....... . .. . .. . .... . . .. . . . Quartz rosettes . . . . . . . . . . . ....... .

R

Raytown member, Iola . . .... .. . Reeds Spring formation .. . Residue assemblages, importance of ..... . . .. .... . . Residue, color of .. .. .... .. ... .. . . . . .. . .. . .. . . . .. . . . . . . . Residue, descriptions of from various Paleozoic formations . .. . .. .. . . . . Residues, geometrical patterns of .. . .. .. . . .. . . .. . . Rock Levee formation .. . . Rock wool, residues of raw material Roubidoux formation

Sandstone, ferruginous, Fortune

s

Sandstone, (Thebes), Maquoketa .... . . ..... . . .. . . Sedalia formation . . .. .. . . .. . .... . . .. . . . Sedimentation, use of residues in study of . . . . . . . . .. . ...... . . ........ . Shale, dolomoldic green, Bonneterre Short Creek oolite, Warsaw . . . . . .. . .. . . .... . .. .. . Silica, coralline, Callaway .... . .. . . Silurian System . . . . . . . . . . . . . . .. . . .. . . . . Sniabar member, Hertha . . . . . . . . . . . . . . . . . . . . . . .. . . . .. . . South Bend member, Stanton Spergen (Salem) formation . . . . . .. . .. . .... . . . Sphalerite, Joachim . . . . . ... ....... . .. . Sphalerite, straw-colored, Callaway .. . . .. . . .. . Spicules, glauconitic, Spergen . . . . . . .... .. . .. . . . Spicules, matted, Warsaw . .. . . .. . .... . . . . ... .. .

29 24 20 19 18 22 20 18

15 22 32 13 14 13 27 33 29

23 26 22 33 31 20 24 25 16 14 19 28 24 19 20

..

Index

Spicules or spines, embedded, Reeds Spring . . . .... . Spicules, siliceous, Bainbridge .. . .. . . ....... . . ...... . . .. . . . Spicules, siliceous, Jefferson City . . . . . . .. . Spicules, siliceous, Spergen Spicules, white, Fortune Spores, Bailey . . ..... . Ste. Genevieve formation Stem-like objects, pyritized, Louisiana .. . . St. Louis formation . . . . .. . . . St. Louis, lithographic limestone . . Stratigraphic correlation by insoluble residues Symbol system for residues, development of

T, U, V Tet1·ataxis, sp. Upper Cambrian Van Buren formation

w Warsaw formation . . . . . . .. . .. . . Westerville member, Cherryvale . . . . . . ....... . . . ... . .. . . .. . Winterset member, Dennis . . . . . . . . . . . . . . . . . . . . . . ....... . . . Worland member, Altamont . . . . . . . . . . . . . ..... . "Worm casts," Chouteau . . . . . . . . . . . . .. . . .

j

39

Page

22 25 29 19 24 25 18 23 18 18 32 12

17 31 30

20 15 15 16 23