R. L Langanhelm, *• Dept. GaoL Umv> ^^^ UiPeno, UU —

STATE OP ILLINOIS

WILLIAM G. STRATTON, Governor

DEPARTMENT OP REGISTRATION AND EDUCATION

VERA M. BINKS, Director

DIVISION OP THE

STATE GEOLOGICAL SURVEY

JOHN C. PRYE. Chief URBANA

REPORT OF INVESTIGATIONS 186

NORTH AMERICAN PALEOZOIC CHITINOZOA

CHARLES COLLINSON and HOWARD SCHWALB

PRINTED BY AUTHORITY OF THE STATE OF ILLINOIS

URBANA, ILLINOIS 1955

STATE OF ILLINOIS

WILLIAM G. STRATTON. Governor

DEPARTMENT OF REGISTRATION AND EDUCATION

VERA M. BINKS, Director

DIVISION OF THE

STATE GEOLOGICAL SURVEY

JOHN C. FRYE. Chief URBANA

REPORT OF INVESTIGATIONS 186

NORTH AMERICAN PALEOZOIC CHITINOZOA

CHARLES COLLINSON and HOWARD SCHWALB

PRINTED BY AUTHORITY OF THE STATE OF ILLINOIS

URBANA, ILLINOIS

1955

ORGANIZATION

STATE OF ILLINOIS

HON. WILLIAM G. STRATTON. Governor

DEPARTMENT OF REGISTRATION AND EDUCATION

HON. VERA M. SINKS, Director

BOARD OF NATURAL RESOURCES AND CONSERVATION

HON. VERA M. BINKS, Chairman

W. H. NEWHOUSE, Ph.D.. Geology

ROGER ADAMS. Ph.D., D.Sc, Chemistry

ROBERT H. ANDERSON, B.S., Engineering

A. E. EMERSON, Ph.D., Biology

LEWIS H. TIFFANY, Ph.D.. Pd.D.. Forestry

W. L. EVERITT. E.E., Ph.D.

Representing the President of the University of Illinois DELYTE W. MORRIS. Ph.D.

President of Southern Illinois University

GEOLOGICAL SURVEY DIVISION

JOHN C. FRYE, Ph.D., D.Sc, Chief

(24458— 2M— 10-55)

STATE GEOLOGICAL SURVEY DIVISION

Natural Resources Building, Urbana

JOHN C. FRYE. Ph.D., D.Sc. Chief

M. M. LEIGHTON. Ph.D., D.Sc, Chief, Emeritus

Enid Townley, M.S., Geologist and Assistant to the Chief

Velda a. Millard, Junior Assis'ant to the Chief

Helen E. McMorris, Secretary to the Chief

RESEARCH

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Physics

R. J. PiERsoL, Ph.D.

GEOCHEMISTRY

Frank H. Reed, Ph.D., Chief Chemist Grace C. Johnson, B.S.. Research Assistant Coal Chemistry

G. R. Yohe, Ph.D., Chemist and Head Earle C. Smith, B.S., Research Assistant GuEY H. Lee, M.S., Research Assistant

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Fluorine Chemistry

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Chemical Engineering

Physicist, Emeriti

Topographic Mapping in Cooperation with the United States Geological Survey.

May 16, 1955

H. W. Jackman, M.S.E., Chemical Engineer and Head R. J. Helfinstine, M.S., Mechanical Engineer and Supervisor of Physical Plant

B. J. Greenwood, B.S., Mechanical Engineer

James C. McCullough, Research Associate (on leave) Robert L. Eissler, B.S., Assistant Chemical Engineer Walter E. Cooper, Technical Assistant Edward A. Schaede, Technical Assistant Cornel Marta, Technical Assistant

X-Ray

W. F. Bradley, Ph.D., Chemist and Head

Analytical Chemistry

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L. D. McVicker, B.S., Chemist

Emile D. Pierron, M.S., Associate Chemist

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(on leave) William J. Armon, B.S., Research Assistant Joseph M. Harris, B.A., Research Assistant JoAnne E. Kunde, B.A., Research Assistant Joan M. Cederstrand, Research Assistant Harold E. Winters, Technical Assistant George R. James, Technical Assistant Frances L. Scheidt, Technical Assistant

MINERAL ECONOMICS

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RESEARCH AFFILIATES IN GEOLOGY

J Harlen Bretz, Ph.D., University of Chicago John A. Brophy, M.S., Research Assistant, State Geologi- cal Survey Stanley E. Harris, Jr., Ph.D., Southern Ulinois Uni- versity

C. Leland Horberg, Ph.D., University of Chicago

M. M. Leighton, Ph.D., D.Sc, Research Professional

Scientist, State Geological Survey Heinz A. Lowenstam, Ph.D., California Institute of

Technology William E. Powers, Ph.D., Northwestern University Paul R. Shaffer, Ph.D., University of Illinois Harold R. Wanless, Ph.D., University of Illinois J. Marvin Weller, Ph.D., University of Chicago

CONSULTANTS

Geology, George W. White, Ph.D., University of Illinois Ralph E. Grim, Ph.D., University of Illinois L. E. Workman, M.S., Former Head, Subsurface Division Ceramics, Ralph K. Hursh, B.S., University of Illinois Mechanical Engineering, Seichi Konzo, M.S., University of Illinois

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May 16. 1955

OTHER TECHNICAL SERVICES

Wm. Dale Farris, Research Associate

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DoNOVON M. Watkins, Technical Assistant

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AUTOMOTIVE SERVICE

Glenn G. Poor, In Charge* Robert O. Ellis, Automotive Mechanic EvERETTE Edwards, Automotive Mechanic David B. Cooley, Automotive Mechanic s Helper

*Divided time

CONTENTS

Page

Introduction 7

Stratigraphic and geographic occurrence 8

Chitinozoans in Superior-Ford C-17 core 8

The systematic position of the Chitinozoa 14

The composition of the chitinozoan test 14

Paleobiology 16

Paleoecology 17

Systematic paleontology 17

References 33

ILLUSTRATIONS

Figure Page

1. Generalized section for southern Illinois 8

2. Map showing locations of wells and outcrops 9

3. Graphic section of a portion of the Superior-Ford C-17 core 10

4. Diagram illustrating nomenclature 15

5. Representatives of Chitinozoa genera 18

6. Holotype of Lagenochitina sacculus 20

7. Diagrammatic representation of y^«^o<:/7///«<3 *^//"/^r<:<^/^ 21

8. Diagrammatic cross section of y^w^oc/^Z/zw^yf^jf^ 22

9. Diagrammatic representation of ^w^«//^<:/!Z//«<2 /<2^«w<rz^/<? 28

10. Holotype of Rhabdochitina ? minnesotensis 30

11. Desmochitina poculum 32

12. Longitudinal section of Desmochitina sp 32

Plates

1 and 2. Paleozoic Chitinozoa 25, 26

Digitized by the Internet Archive

in 2012 with funding from

University of Illinois Urbana-Champaign

http://archive.org/details/northamericanpal186coll

NORTH AMERICAN PALEOZOIC CHITINOZOA

CHARLES COLLINSON and HOWARD SCHWALB

ABSTRACT

Chitinozoans have received little study by American paleontologists but newly re- ported occurrences from Ordovician, Silurian, and Devonian strata in North America suggest that they may become important stratigraphic indices. A rapid reconnaissance of wells, outcrops, field notes, etc., has yielded eighteen geographic occurrences and leads us to believe that these microfossils are widely distributed and abundant in the Paleozoic. More than 500 specimens have been examined. Study of a complete Silurian-Devonian core sequence in White Co., 111., has shown chitinozoans occur in three separate zones and represent two faunules.

The taxonomic position of the Chitinozoa is discussed, and it is concluded that these microfossils represent an extinct order of rhizopod protozoans. The common association of chitinozoans and glauconite in the Clear Creek chert suggests that these microorganisms lived in relatively shallow marine waters in a moderately anaerobic environment.

All previously recorded genera are briefly described, and two new genera, Ampulla- chitina and Illichitina, are proposed. All known species are listed and eleven new species from Illinois are described and illustrated.

INTRODUCTION

IN RECENT YEARS the existence of the Chitinozoa has been virtually forgotten by paleontologists and stratigraphers. In Europe, where they were first described, there has been little progress in knowledge of these fossils for more than a decade. In the United States they have never received significant attention from paleontologists, although some subsurface stratigraphers have used zones in which chitinozoans are abundant as stratigraphic markers without knowing the nature of the fossils. Oil geol- ogists in the Eastern Interior Basin and Illinois Geological Survey stratigraphers have used abundance of these "black spore- like bodies" as a criterion for recognizing the Clear Creek chert for a number of years. In some areas abundance of the "black spores" has been used to define the limits of the formation.

Because of the abundance of chitinozoans and their importance to the oil industry as stratigraphic markers, the authors in 1953 began to collect and study these microfossils. The Superior Oil Company-H. C. Ford et al. C-17 core from White Co., 111., then became available for study and, as the en- tire Silurian-Devonian section was cored in that test, we initiated a study to determine the precise range and abundance of chitino-

zoans in the core. Although more than 500 specimens from the Superior core provide the nucleus for this study, a number of other occurrences of chitinozoa in the Mid- west were found as study progressed. So much material has been obtained that this paper should be considered a progress report and a basis for further study.

We believe that Chitinozoa are so widely distributed in the lower Paleozoic of North America that they offer promise of becoming an important tool for outcrop and subsur- face correlation. Several characteristics fa- vor their use as stratigraphic indices: 1) they are of widespread geographic occur- rence, 2) they consist of material that is virtually indestructible, so they are abun- dantly preserved and may be recovered from concentrated hydrofluoric, sulfuric, hydro- chloric, or other acid residues, 3) they are easily recognizable in outcrop and well sam- ples, and 4) they are small and have enough distinguishing features to be identified even in finely crushed well samples. Determina- tion of their value as index fossils now de- pends upon detailed study by micropaleon- tologists and stratigraphers, and we hope that this study will serve as a basis for re- newed interest in the microfossils.

It is a pleasure to acknowledge help from several colleagues of the Illinois Geological Survey. H. B. Willman and D. H. Swann

[7]

8

ILLINOIS STATE GEOLOGICAL SURVEY

read and criticized the manuscript and gave information and encouragement throughout the study. R. M. Kosanke gave information that greatly aided our work, especially dur- ing the early stages of the project. We are also indebted to W. F. Bradley, who made our X-ray photographs, to James Baxter, who discovered chitinozoans in the Silurian of Illinois, and to Alan Scott, who made most of the text figures.

STRATIGRAPHIC AND GEOGRAPHIC OCCURRENCE

Eisenack coined the name Chitinozoa in 1931 for a previously undescribed group of "chitinous" microfossils that he obtained from Ordovician and Silurian rocks of the East Prussia Baltic region of Europe. In subsequent publications, he, DeFlandre, and Lewis extended the known range and occur- rence of the Chitinozoa in Europe to the

z <

O

> UJ Q

UPPER

New Albany (part)

Alto

MIDDLE

Lmqle

Grond Tower

Dutch Creek

Cleor Creek

LOWER

Rnnkhone

Boiley

2 <

q:

=) -I if)

NIAGARAN

Moccasin Springs

St. Cloir

ALEXANDRIAN

Sexton Creek

Edgewood

•2. <

o

>

o

Q

or o

CINCINNATIAN

Moquoketo

Fernvole

MOHAWKIAN

Kimmswick

Decoroh

Plattin

Joachim

Dutchtown

CHAZY

St Peter

Everton

1 1

1

• 1 1

w

1

1 lA

Al 1

1

1 1

1

1

— r-' — r—

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Fig. 1. — Generalized section for southern Illinois showing* all reported stratigraphic oc- currences of chitinozoans. The Maquo- keta occurrence is in northern Illinois, the Moccasin Springs in the Racine of north- ern Illinois, and the Decorah in southern Minnesota.

Silurian of the Montagne Noire of southern France, the Ordovician of northern Wales, the Ordovician of western Germany, and the Ordovician of western Czechoslovakia.

Stauf^er (1933) reported the first chitin- ozoan species from the western hemisphere when he described Rhahdochit'ina ? minne- sotensis from the Middle Ordovician Dec- orah formation of Minnesota. Cooper (1942) reported that chitinozoans range from the Ordovician to the Devonian in North America, and Lange (1949) de- scribed a single species from the Devonian of Brazil.

Our study leads us to believe that the Chitinozoa are abundant and widespread in Midwestern United States and that they will be found to be abundant elsewhere. We have learned from L. E. Workman, Canadian Stratigraphic Service, Ltd., Cal- gary (personal communication), that chitin- ozoans are common in the Devonian rocks of Alberta. While this report was being completed, an occurrence of chitinozoans in the Upper Ordovician Maquoketa shale in a well in Lake County, 111., was discovered. All occurrences of chitinozoans in North America known to us, other than the above- mentioned two, are shown in figure 2, and the occurrence of all known species are listed under the discussion of each respec- tive genus. It is emphasized that the known occurrences listed are the results of a recon- naissance examination of wells and outcrops and probably represent only a small frac- tion of the total occurrences in Illinois and adjacent states.

Chitinozoans in Superior-Ford C-17 core. — The results of a detailed study of the lithology, chert percentages, insoluble resi- dues, and occurrence of chitinozoans in the Superior Oil Co.-Ford C-17 core are illus- trated in figure 3. Examination of the chi- tinozoans was undertaken as part of a gen- eral study of the core. The lithologies of the whole core were described, the amount of chert present was estimated visually, and the core was sampled every foot. Half of each sample was retained as a hand speci- men and the other half was crushed for in- soluble-residue and other analyses. Ten to 20 grams of crushed material from each sam-

STRATIGRAPHIC AND GEOGRAPHIC OCCURRENCE

I7«

V

• \ WISCONSIN

MINNESOTA N

\

IOWA

-\r

KEY

® Middle Devonian ?

9 Middle Devonian

© Lower Devonian

-^ Middle Devonion on( ^ Lower Silunon

-^ Middle Silunon

4 Middle Ordovicion

y Devonian top ot seo level

Scole of Miles p . 100

TENNESSEE

BLACK ^ «>I5

/warrior

BASIN

Fig. 2. — Map showing locations of wells and out- crops from which chitinozoans have been collected, (In Illinois, unless otherwise noted.)

1. Mulford Engineering Service-Thornton well, sec. 34, T. 36 N., R. 14 E., Cook Co., depths 145-150 feet, Racine formation.

2. Allen and Sherritt-Biggs well 1, sec. 9, T. 11 N., R. 14 W., Clark Co., depths 1425-1445 feet. Clear Creek chert.

3. National Assoc. Petroleum Co.-Handley well 1, sec. 26, T. 10 N., R. 7 E., Cumberland Co., depths 3736-3743 feet. Grand Tower forma- tion.

4. Northern Ordinance, Inc.-Sapp well 1, sec. 5, T. 2 N., R. 5 E., Clay Co., depths 4650- 4670 feet, Clear Creek chert.

5. Magnolia Petroleum Co.-Youngs well 28, sec. 20, T. 2 N., R. 2 E., Marion Co., depths 3406- 3440 feet, Clear Creek chert.

6. Superior Oil Co.-Williams et al. well 1, sec. 22, T. 2 N., R. 1 E., Marion Co., depth 3480 feet, Clear Creek chert.

7. Shell Oil Co.-Ragan well 1, sec. 25, T. 2 S., R. 1 E., Jefferson Co., depths 3900-3935 feet, Bailey formation.

8. Shell Oil Co.-Schubert well Al, sec. 23, T. 4 S., R. 2 W., Perry Co., depths 2974-3014 feet, Clear Creek chert.

9. Superior Oil Co.-H. C. Ford et al. well C-17, sec. 27, T. 4 S., R. 14 W., White Co.; see fig- ure 2 for distribution.

10. Phillips Oil Co.-Garr well 1, sec. 31, T. 4 S., R. 11 E., White Co., depths 5120-5130 and 5150-5155 feet, Clear Creek chert.

11. Burr Lambert Co.-Hagler well 1, sec. 28, T. 10 S., R. 2 W., Jackson Co., depths 2400- 2565 feet, Clear Creek chert.

pie was dissolved in 10 percent hydrochloric acid, and the resulting residue was weighed and examined for microfossils. Many free chitinozoans were found in the residues, and the total abundance was visually estimated and plotted.

The location of the core in the central and deepest part of the Eastern Interior Basin (fig. 2, well 9) makes it of key im- portance, for it is about equidistant from the relatively complete outcrop-sections of Silurian-Devonian strata in the southwest- ern Illinois Grand Tower area, the cen- tral Tennessee Wells Creek area, and the Louisville area of Kentucky and Indiana. So far, outcrops containing chitinozoans have been reported only from the Grand Tower area but as far as we know they have not been sought in the other outcrop areas.

The chitinozoans occur in three zones in the core — two thick zones in the Middle Devonian Clear Creek chert and one thin zone in the lower part of the Lower Si- lurian Sexton Creek formation. In the Clear Creek, which is generally defined as a cherty limestone or calcareous chert unit, the zones extend from 4990 to 5100 feet and from 5205 to 5456 feet, respectively. They coincide closely in each case with sili- ceous, dolomitic portions of the core and are separated by about a hundred feet of relatively pure limestone without chitino- zoans. Such coincidence of the chitinozoans

12. F. Lyrler-Baysinger well 1, sec. 32, T. 10 S., R. 3 W., Jackson Co., depths 270-295 feet, Bailey formation.

13. Little Egypt Oil Co.-Bassler well 1, sec. 35, T. 11 S., R. 1 W., Union Co., depths 2425- 2824 feet. Clear Creek chert.

14. Hobson and Holman-J. T. West well 1, 1-F- 26, Christian Co., Ky., depths 2285-2330 feet, Clear Creek chert.

15. Gerre Jordan well 1, Hardin Co., Tenn., depth 80 feet, questionable Devonian.

16. Blocks of rock believed to be Grand Tower limestone excavated for foundation of an aerial pipeline crossing tower near Devils Bakeoven, sec. 23, T. 10 S., R. 4 W., Jackson Co.

17. Outcrop in lower part of Decorah shale, 5 feet above the base of the formation. Ford Bridge, Minneapolis, Minn.

18. Outcrop in the shale just above the "marble layer," 4j/^ feet above the base of the Decorah shale, Lieb Quarry, Faribault, Minn,

10

ILLINOIS STATE GEOLOGICAL SURFEY

Limoloqit log of core

Estimated % of chert in core

Insoluble resrdue by %

Zi

<

KEY

I I I limestone

[^ff^ chert

|-------| siltstone

[^^^â– ^ shole

[•".•■.•-.'•■I sandstone

SYMBOLS

a glouconite

-^_L. dolomitic

A cherty

ooo oolitic

-ro----r- siity

_i_ -^ colcoreous

-^:^- orgilloceous

R red color

y •■-■•■ •";■.■ sondy

Fig. 3.

STRATIGRAPHIC AND GEOGRAPHIC OCCURRENCE

11

Fig. 3. — (Continued)

12

ILLINOIS STATE GEOLOGICAL SURVEY

LitholoqK log of core

Estimoted % of chert in core

Insoluble residue by %

TM

m

im

DHI

^mi

33^

31^

j^^

3Z^

n^

ffi

0^

^mi

3^n

§^1:

EHS

SI:

imi

^EW

m^

TIL

^p=^

-J^

3HIz

^

<

Fig. 3. — (Continued)

STRATIGRAFHIC AND GEOGRAPHIC OCCURRENCE

13

MOCCASIN 595^ SPRINGS

ST. CLAIR

SEXTON CREEK

EDGE- WOOD

MAQ.

Lifhologic log of core

3=

33E

m

311

lEIL

Estimoted % of

Fig. 3. — ^Continued) — Graphic section of a portion of the 6-inch Superior- Ford C-17 core, sec. 27, T. 4 S., R. 14 _W., White Co. The core was completed in 1952 and the portion shown is continuous. Oil-base mud was used in drilling and the electric log should be interpreted accordingly.

with the siliceous strata might lead to the conclusion that the chitinozoans owe their preservation to the slllcification of the beds. However, as mentioned above, many of the Chitlnozoa were dissolved from the cal- careous portions of the core. This points to the possibility that chitinozoans may have flourished in environments favorable to the deposition of chert whether that be governed by the depth, pH of the water, or some other factor. The following species occur In both zones of the Clear Creek.

Lagenochitina brevicervicata n. sp. L. elongata n. sp. Angochitina flasca n. sp. A. pusilla n. sp.

L. brevicervicata and A. flasca are very common to abundant ; the other two species are rare to common. A number of Bairdia- like ostracodes were found associated with Chitlnozoa between depths of 5267 and 5395 feet. Sponge spicules were noted at a 5385-foot depth, and a single occurrence of bryozoa was recorded at a depth of 5489 feet.

Glauconlte, which Is characteristic of the Clear Creek, occurs throughout the forma-

tion, but It Is most common In the two chl- tlnozoan zones. Cloud (1955, p. 490) gives physical limits for glauconlte forma- tion. The limits that appear to be signifi- cant In Indicating the environment of the Clear Creek and Its chitlnozoan fauna are : 1) It occurs off most oceanic coasts and mainly on the continental shelves away from large streams; 2) It Is known to originate only In marine waters of normal salinity; 3) Its formation requires at least slightly reducing conditions, at sites of origin within the enclosing sediments; 4) Its formation Is facilitated by the presence of decaying or- ganic matter, which results In reducing con- ditions. The bottom habitat is favorable to sediment-ingesting organisms with low oxy- gen requirements; 5) Its formation is fa- vored in the upper part of the 10 to 400 fathom Interval. It Is rare to uncommon at other depths; 6) It has a wide range of temperature tolerance; and 7) It is com- monly associated with remains and fecal pel- lets of sediment-ingesting organisms. It Is rare In beds that are rich in algae, corals, or bryozoans. The presence of ostracode shells is not out of keeping with such an environ- ment as outlined by Cloud, and the condi-

14

ILLINOIS STATE GEOLOGICAL SURVEY

tions are favorable to protozoans, such as we believe the Chitinozoa to be.

The third chitinozoan zone was found in the lower part of the Sexton Creek forma- tion between depths of 6065 and 6075 feet, where the rock is a cherty argillaceous lime- stone. Two species were common, Ampul- lachitina laguncula and Illichitina crotalurn. Some glauconite is present in the upper part of the formation, but it immediately overlies the zone of Chitinozoa.

THE SYSTEMATIC POSITION OF THE CHITINOZOA

There has been considerable doubt about the precise zoological affinities of the Chitin- ozoa. Eisenack (1931), in the first report on the fossils, stated that he believed them to be related to the rhizopod order Theca- moebaea (Testacea), which contains genera with structureless chitin-like tests. Such re- cent Thecamoebaea genera as Diplophrys Barker, Micrometes Cienkowski, Lieber- kiihnia Claparede and Lachmann, Micro- gromia Hertwig and Lesser, and Gromia Dujardin contain species that not only have structureless chitin-like tests but compare in size, shape, and color to the fossil Chitino- zoa Lagenochitina and Desmochitina. Ei- senack stated, however, that living members of the Thecamoebaea live mainly in fresh water and he noted that their shells are solu- ble in potash lye whereas those of the Chi- tinozoa are not.

In 1932 Eisenack called attention to the similarity between the flagellate protozoan genus Trachelo?no7ias Ehrenberg and some chitinozoans. Some species of Trachelo- monas float about in a brittle covering which extends away from the body and is gener- ally colored brown by iron oxide. The tests are thick and possess necks and collars much like Lagenochitina, Angochitina, and Des- mochitina. Some are smooth, others cov- ered with short spines. The material of the tests is apparently different in comparable species of the two groups, however, as the Trachelomonas test is composed of cellu- lose. Furthermore, the genus is only known to occur in fresh water. These factors, Ei- senack wrote, seem to oppose any connection

between the flagellates and the Chitinozoa. He did, however, indicate a strong belief that the Chitinozoa are protozoans.

Jepps (1926) published a detailed study of the Thecamoebaea species Gromia ovi- formis Dujardin, which occurs in great quantity along the seashore of Great Brit- ain. The similarity of this form to such chitinozoan genera as Lagenochitina and Angochitina is certainly close. G. oviformis is almost spherical, being either slightly de- pressed or ellipsoidal in general shape with a small mouth at one end of the long axis. The shape of the animal is constant because of the rigid pseudochitinous test. The mouth is bordered by a neck, such as is found in Lagenochitina brevicervicata, and the neck carries a soft collar through which the pseudopodia are extruded. The collar may be extended or retracted as the pseudopodia are extended or retracted. The oral dia- phragm of some chitinozoans may have been flexible enough to have performed a similar function. The test or chamber of G. ovi- formis is composed of an outer perforate layer and a thinner structureless inner layer. The two layers appear to correspond to the tegmen and chamber wall found in Lagenochitina (fig. 6).

The composition of the chitinozoan test. — One of the most important factors to be considered in determining the affinities of Chitinozoa is the nature of the material that composes the test. Jepps in 1926 reported the results of analyses in which she sub- jected the shells of the Recent Theca- moeba Gromia oviformis to several analyses. They indicated that the inner layer of the test is insoluble in acetic acid, hydrochloric acid, or cold 50 percent caustic potash. In boiling caustic potash the basal membrane broke up, presumably as the result of the violent boiling. The outer layer of the shell resisted solution in all the solvents except caustic potash, which dissolved the layer in one week. The collar dissolved in both the hydrochloric acid and the caustic potash but was insoluble in dilute acetic acid. Jepps came to the conclusion that the outer layer is composed of pseudochitin but gave no opinion concerning the structureless inner

SYSTEMATIC POSITION OF CHITINOZOA

15

oral aperture or mouth

— collar

lip diaphragm

branched spine

bifid spine

chamber wall

neck-|

copula aboral flange

aboral pit

aboral

B

Fig. 4. — Diagrams of hypothetical chitinozoan individual (A) and chain (B) illustrating the terminology used in this report. The terms proximal and distal used in previous chitinozoan studies are aban- doned because they have been applied in a sense contrary to general usage of the terms.

layer, although her analyses seem to show that it is of a pseudochitinous nature also.

Eisenack (1931) conducted a number of experiments in an attempt to determine the chemical composition of the chitinozoan test. He found the tests completely resist- ant to heating with concentrated hydrochlo- ric acid, concentrated hydrofluoric acid (40 percent), or concentrated potash lye (20 and 50 percent), even when the specimens are heated in these solutions for long periods at 100° C. The Chitinozoa were heated up to 200° C. in 90 percent sulfuric acid and did not dissolve. Eisenack noted that chitin from modern animals is affected by caustic soda if the chitin has already been hydro- lized by heating with hydrochloric acid or

sulfuric acid. As the result of these tests, he recognized that there seems to be a dis- tinct difference in composition between modern chitin and the tests of the Chitino- zoa, but he concluded that the chitinozoan test is probably stabilized by an anhydrous structure that resists hydrolyzation.

Clark and Smith (1936) performed a series of experiments on chitin from the carapace of the lobster Homarus ameri- canus, and they noted the following char- acteristics: 1) The chitin occurs in long fibrils that can be teased apart after treat- ment with absolute alcohol; 2) The chitin is soluble in hot saturated sodium hydrox- ide; 3) The chitin is soluble in concen- trated mineral acids such as HCl but is un-

16

ILLINOIS STATE GEOLOGICAL SURVEY

attacked by others. Even at room tempera- ture, chitin is hydrolyzed in hydrochloric acid.

Kesling (1951, p. 70-71) took an X-ray powder photograph of dried Daphiiia longi- spina, which are said to be made entirely of chitin. The film showed only very diffuse halos of high d values (approximate values of 4.5 and 11. 7a at the center of the dif- fuse bands). Clark and Smith published powder patterns of lobster chitin that were very diffuse, indicating an almost amor- phous structure.

W. F. Bradley made X-ray photographs for us of the test wall of several broken rep- resentatives of Angochitirm flasca. The re- sults were comparable with those quoted by Kesling for Daphnia. However, as also noted by Kesling, the halos are too diffuse to be used as proof that the material X-rayed was or was not chitin.

The experiments by Jepps, from which she concluded that Gro?fiia is pseudochitin- ous, the analyses made by Clark and Smith on chitin from the lobster Homarus, and the work by Eisenack on chitinozoans lead to the conclusion that the composition of the Chitinozoa is close to that of Gromia and not very close to true chitin. If allowance is made for any changes in composition of the chitinozoan tests during preservation, then an original composition of pseudo- chitin seems probable.

In general shape, such choanoflagellates as the marine protomonad genera Salpin- goeca James-Clark and Conodoeca James- Clark closely resemble the chitinozoan spe- cies Angochitina bifurcata, and Lagenochi- tina sacculus. Furthermore, these flagellate genera contain species that possess chitin- like tests and soft oral collars and are either attached by a stalk or are free-swimmers. These characteristics speak strongly for classification of the Chitinozoa with the flagellates. However, very few pseudochi- tinous or marine flagellate genera are known, and forms with relatively thick tests, such as are characteristic of the Chi- tinozoa, are very rare.

Among the rhizopods, thick pseudochitin- ous tests are very common, and there are many more marine genera than among the

flagellates. Oral collars and flagella are known but are uncommon ; attachment or- ganelles, whose presence is reflected in the shape of the test, are rare. Nevertheless, there are many species of sessile rhizopods. Thus the Chitinozoa have characteristics in common with both flagellates and rhizopods but do not fit perfectly into either class. Furthermore, neither class possesses such chitinozoan features as bifurcate and branched spines or thick oral diaphragms. Therefore it seems best to consider the Chitinozoa as an extinct order of marine protozoans which, because of their thick pseudochitinous tests and marine habitat, we are referring to the class Rhizopoda (Sarcodina). Chitinozoa may be a mis- nomer in that the microfossils seem to be composed of pseudochitin.* The term is re- tained, however, because of its previous usage and because many paleontologists use the word chitin in a broad sense for any horny organic substance.

PALEOBIOLOGY

Any attempt to describe the biology of the Chitinozoa is partly based upon their identification as rhizopods and the assump- tion that they lived much as modern forms do. There are, however, several charac- teristics of the Chitinozoa that give clues to their mode of life. For example, the aboral pit, which is present on many chitin- ozoan species, may have served as a recep- tacle for a stalk or other kind of holdfast organelle. Forms with pits therefore may have been benthonic, whereas such forms as Angochitina bifurcata and Ampidlachi- tlna laguncula, w^hich possess spines and no aboral pit, were probably floaters. The col- lared chitinozoans are much like living flag- ellates. It seems reasonable to presume their collar functioned like the flagellate collar and w^as a food-gathering device that may have paralyzed algae or other microscopic organisms that came in contact with it.

From comparison with modern forms, we infer that most of the Chitinozoa gathered

* Hyman (1940. p. 55) slates "pseudochitin is a glyco- protein, a combinalion of protein and carbohydrate, similar chemically to mucin (slime). Chitin is non-protein and consists of acetic acid united to glucosamine (the sugar glucose with one OH group replaced by NH2)."

SYSTEMATIC PALEONTOLOGY

17

food and moved by use of pseudopodia or flagella extended from the oral aperture. Reproduction among living rhizopods is chiefly by binary fission but also by multiple fission and budding. In many cases the life cycle includes production of flagellate swarmers, and some forms are flagellate at times in the adult state. In some genera re- production involves an alternation of sexual and asexual generations, and the adult is commonly dimorphic. In simple species, however, the two forms cannot be distin- guished. Such may also be the case with some chitinozoans. In the chitinozoan genus Desmochitina two to six individuals are commonly found in chains that may be similar to the chains of the dinoflagellate Ceratiuni that are formed by repeated bi- nary fission.

PALEOECOLOGY

So far, chitinozoans have been found mainly in limestone but great numbers have also been recovered from chert, dolomite, and shale. Where found, the fossils are very abundant and occur in a considerable range of sizes. Often such delicate features as bifurcate spines and translucent collars are preserved. These facts seem to indicate that the faunas have not been transported any significant distance and that in most cases they represent a life assemblage. In each assemblage one or two species predom- inate. Other species are very rare and may merely represent specific variants or muta- tions of the predominant species.

In one southern Illinois occurrence, De- vonian chitinozoans were found associated with scolecodonts. In the Superior-Ford C-17 core, ostracodes were commonly found with chitinozoans throughout a 128-foot zone; some sponge spicules and one bryo- zoan were also found associated with chi- tinozoans. With the exception of the bryo- zoan, all these associated forms could have lived and flourished in an oxygen-poor en- vironment, such as Cloud has stated (see p. 13) is required for the formation of glau- conite. These conditions along with the other requirements for glauconite forma- tion listed by Cloud may very well outline the environment of the Chitinozoa.

SYSTEMATIC PALEONTOLOGY

The Chitinozoa were established by Ei- senack in 1931 and revised by the later work of Eisenack and DeFlandre. For the rea- sons outlined above, we are recognizing Chitinozoa as an order and placing it in the class Rhizo'poda. Revision of existing classi- fication has been held to a minimum in an- ticipation of more extensive studies. How- ever, a few changes have been made in order to effect a more natural and useful classi- fication. The polymorphic genus Conochi- t'lna is restricted to slightly tapered forms, and the genera Ampullachitina n. gen. and lUichitina n. gen. are erected for ampulla- shaped forms with long necks and bell- shaped forms, respectively. In addition, two species, Conochitina lageno7norpha Eisenack and C. filifera Eisenack, are referred to Aiigochitina.

Phylum Protozoa Goldfuss, 1818

Class Rhizopoda Dujardin, 1841

Order Chitinozoa Eisenack, 1931

Axially sj^mmetrical marine organisms with simple but varied rod-, club-, flask-, or trumpet-shaped tests. Individuals range from about .03 mm. to .5 mm. in length. The test, which we believe to be pseudo- chitinous, is generally black, structureless, and opaque. In some species the test is brown or amber and is translucent. The test is open at one end, the oral, and closed at the other end, the aboral. The surface of the test may be very smooth, tuberculate, or hispid. In combination with any of these surface textures, the test may possess either simple or branched spines.

The organisms occur either singly or in chains of several individuals. The most in- dividuals found in a chain is six. Strati- graphically they are known to occur from the Middle Ordovician to the Middle De- vonian. They have been found in the United States, Canada, Brazil, Wales, Ger- many, France, and Czechoslovakia.

Family Lagenochitinidae Eisenack, 1931

As defined by Eisenack, this family con- sists of flask-shaped individuals that have their greatest diameter near the midlength.

18

ILLINOIS STATE GEOLOGICAL SURVEY

Fig. 5. — Representatives of all genera of Chitinozoa, with omission of the genus Ampullachitina (fig. 9).

All except figure A are holotypes upon which the genotypes of genera published prior to this re- port are based. (A) Illichitina cervicornis (Eisenack); (B) Angochitina echinata Eisenack; (C) Lagenochitina baltica Eisenack; (D) Mirachitina qiiadrupedis Eisenack; (E) Acanthochitina barbata Eisenack; (F) Desmochitina nodosa Eisenack; (G) Parachitina curvata Eisenack; (H) Conochitina claviformis Eisenack; (I) Rhabdochitina magna Eisenack. All after Eisenack.

The chamber tapers gradually to a tubular neck which is terminated by a smooth mouth.

Genus Lagenochitina Eisenack, 1931 Genotype : Lagenochitina baltica Eisenack

The genus contains flask-shaped forms without spines. The genotype was origin- ally described from the Ordovlclan Ostsee- kalk of the East Prussia Baltic region. The genus now contains the following species:

L. cylindrica Eisenack — Ordovician lime- stone, East Prussia Baltic region.

L. prussica Eisenack — Ordovician Ostsee- kalk. East Prussia Baltic region.

L. sphaerocephala Eisenack — Silurian Beyrichienkalk, East Prussia Baltic region, Ordovician (E^) of Kozel, western Czecho- slovakia (Bohemia) ; Silurian of Combe d'Izarne in the Montagne Noire of south- ern France.

L. boheniica Eisenack — Ordovician T)^i of Sarka, western Czechoslovakia (Bohe- mia).

L. brevicervicata n. sp. — Middle Devo- nian Clear Creek chert of southern Illinois and southern Tennessee.

L. elongata n. sp. — Middle Devonian Clear Creek chert of southern Illinois.

L. sphaerica n. sp. — Middle Devonian Clear Creek chert of southern Illinois.

L. sacculus n. sp. — Lower Devonian Bai- ley formation of southern Illinois.

Lagenochitina brevicervicata Collin- son and Schwalb, n. sp.

Plate 1, figures 16-19; plate 2, figures 11-13

Diagnosis. — Chamber subspherical, slight- ly elongate; terminated orally by simple mouth at end of very short rather indistinct neck; terminated aborally by small obscure papilla with external pit ; chamber wall thin

SYSTEMATIC PALEONTOLOGY

19

and opaque; exterior surface finely tuber- culate.

Re?narks. — This species is known from the Clear Creek chert of southern Illinois, where it is very common in some zones, and from beds of questionable Middle Devonian age in southern Tennessee.

The holotype of this species (pi. 2, fig. 13) is a large individual .21 mm. in maxi- mum diameter and .25 mm. long. The oral end of the holotype has been compressed laterally during preservation, but before deformation must have been about 1/3 the diameter of the chamber. The lip appears to have been simple and smooth. The cham- ber walls of the species are thin and there is a thin oral diaphragm at the base of the neck. The diaphragm has a single oral aper- ture about 1/3 the diameter of the neck.

Nearly all representatives of this species have been deformed to some extent during preservation. Flattened specimens, such as those shown in plate 1, figures 18 and 19, make up a large percentage of the individ- uals observed. The thin chamber walls probably account for the large proportion of crushed specimens.

L. brevicervicata is related to L. sphae- rica, but the latter has a long neck and the aboral papilla is large and distinct. The spe- cific name brevicervicata is chosen because the short neck is characteristic of the spe- cies.

Occurrence. — Middle Devonian Clear Creek chert in the following wells : 1 ) Magnolia Petroleum Co.-Youngs well 28, sec. 20, T. 2 N., R. 2 E., Marion Co., 111., where this species is abundant in the top 10 or 20 feet of the chert. The small paratype illustrated in plate 1, figure 16, came from a depth of 3407 feet; 2) Superior-Ford well C-17, sec. 27, T. 4 S., R. 14 W., White Co., 111., where this species occurs at depths of 5310 to 5380 feet. The holotype shown in plate 2, figure 13, and the para- types illustrated in plate 1, figures 17-19, and plate 2, figures 11 and 12, came from a depth of 5376 feet; and 3) Burr Lambert Co.-Hagler well 1, sec. 28, T. 10 S., R. 2 W., Jackson Co., 111., where the species is common at depths of 2560 to 2565 feet.

Several representatives of the species have been found in Gerre Jordan well 1 in Har- din Co., Tenn., where the specimens were found in rocks of questionable age. As all other occurrences of this species are in rocks of Middle Devonian age, the same age seems indicated for the Tennessee speci- mens.

Repository. — Illinois Geological Survey.

Lagenochitina elongata Collinson and Schwalb, n. sp.

Plate 2, figure 10

Diagnosis. — ^Chamber subovoid, elon- gate, flattened basally; terminated orally by thin collar at end of short neck; terminated aborally by prominent papilla; chamber wall moderately thick and opaque ; exterior sur- face smooth.

Remarks. — This species is based on a sin- gle distorted but well-preserved specimen .16 mm. in maximum diameter and .30 mm. long. As shown by plate 2, figure 10, the chamber of the holotype has a large rupture, which appears to have been made during or shortly after the life of the specimen, while the test was still relatively flexible. A rem- nant of a thin translucent oral collar is pre- served.

The holotype was found in subsurface Clear Creek chert in southern Illinois. The specimen is clearly referable to Lagenochi- tina because its maximum diameter is near the midlength. However, its general shape approaches that of the genotype of Cono- chltina, C. claviformis Eisenack. L. elon- gata is not closely similar to any other spe- cies.

Occurrence. — Superior-Ford well C-17, sec. 27, T. 4 S., R. 14 W., White Co., 111., from a depth of 5303 feet.

Repository. — Illinois Geological Survey.

Lagenochitina sacculus Collinson and Schwalb, n. sp.

Figure 6

Diagnosis. — Chamber pyriform ; termi- nated orally by long thin translucent cylin- drical collar; mouth simple; neck indis-

20

ILLINOIS STATE GEOLOGICAL SURVEY

Fig. 6. — The holotype of Lagenochitina sacculus n. sp., a natural section in white chert, X370. Note the presence of a tegmen.

tinct; very broadly rounded aborally ; cham- ber wall thin and opaque ; external surface appears smooth.

Remarks. — This species is known from the holotype and three paratypes found in the Lower Devonian Bailey formation of southern Illinois. The holotype is well pre- served in chert and is .12 mm. in maximum diameter and .20 mm. in over-all length. The collar is .07 mm. long, and the diameter of the mouth is about 1/5 that of the cham- ber. Although the chamber wall is opaque, it is covered by a thin brown translucent tegmen. The collar is joined to the cham- ber in such a fashion that the lip of the mouth serves as a flange for attachment (fig. 4).

L. sacculus is reminiscent of Arigochitiiia ftasca from the Clear Creek chert but is smaller and apparently possesses neither spines nor aboral papilla. In general shape, L. sacculus is much like Angochitina bifur- caia, with which it was found associated, but L. sacculus is larger, possesses no spines, and has an opaque rather than translucent chamber wall.

The specific name sacculus (Latin) means "little bag," and describes the general shape of the species.

Occurrence. — Lower Devonian Bailey formation in the F. Lyrler-Baysinger well 1, sec. 32, T. 10 S., R. 3 W., Jackson Co., 111., from depths of 270 to 275 feet.

Repository. — Illinois Geological Survey.

Lagenochitina sphaerica Collinson and Schwalb, n. sp.

Plate 1, figures 7-15

Diagnosis. — Chamber spherical to sub- spherical ; terminated orally by flared collar at end of short neck; terminated aborally by prominent papilla with pit ; chamber wall thick and opaque; exterior surface finely tuberculate.

Remarks. — This species is known from the Middle Devonian Clear Creek chert and possibly from the Bailey formation of the subsurface of southern Illinois. The holotype (pi. 1, figs. 7, 9, and 10) is a large, very well preserved specimen .22 mm. in maximum diameter and .27 mm. long. It is incomplete orally, as were all repre- sentatives of the species observed. The di- ameter of the neck is equal to about one- third that of the chamber. In most specimens there is little doubt that a collar was once present. The collar of the holotype is trans- lucent and only partially preserved (pi. 1, fig. 9). Its wall is much thinner than that of either the neck or the chamber. Although the presence of an oral diaphragm could not be determined in the holotype, a natural sec- tion of a paratype (plate 1, fig. 8) clearly shows a thick diaphragm which has at least one small aperture. The exterior tubercu- late surface of the holotype is shown on plate 1, fig. 7. The paratypes (pi. 1, figs. 8 and 11-15) illustrate the common state of preservation of this species as well as the variation in basal flattening and size of the aboral papilla.

This species is very similar in size and general shape to L. brevicervicata, with which it is associated, although the latter is distinguished by its very short indistinct neck. L. sphaerocephala Eisenack from the Silurian of the East Prussia Baltic region is the European species most like L. sphaerica but Eisenack's species has a very long neck.

SYSTEMATIC PALEONTOLOGY

21

In general shape Desmochitiiia? urna Eisen- ack resembles the species under considera- tion but Z).? urna possesses a basal flange.

Occurrence. — Middle Devonian Clear Creek chert at depths of 2500 to 2565 feet in Burr Lambert Co.-Hagler well 1, sec. 28, T. 10 S., R. 2 W., Jackson Co., III., and Hobson and Holman-J. T. West well 1, l-F-26, Christian Co., Ky., at depths of 2285 to 2330 feet. The holotype and para- types illustrated on plate 1, figures 7-10 and 13-15, came from between 2500 to 2505 feet depths in the Illinois well. The para- type figured on plate 1, figures 11 and 12, came from between 2560 and 2565 feet in the same well.

Repository. — Illinois Geological Survey.

Genus Angochitixa Eisenack, 1931 Genotype: Angochitina echinata Eisenack

Figure 5B

Angochitina differs from Lage?iochitina in that the former possesses surface spines. The genotype is from the Silurian Beyrichi- enkalk of the East Prussia Baltic region. Two other species were assigned to the genus by Eisenack, A. capillata and A. elon- gata, both from the Ordovician or Silurian of the Baltic region. We have assigned three additional species to the genus, A. pusilla and A. flasca from the Middle De- vonian Clear Creek chert and A. bifurcata from the Lower Devonian Bailey forma- tion, all from the subsurface of southern Illinois. Also, we believe that two species assigned to Conochitina by Eisenack should be referred to Angochitina — C. lagenomor- pha Eisenack, from the Silurian of the East Prussia Baltic region and questionably from the Silurian of the Montagne Noire in southern France, and C. filifera Eisenack, from the Silurian of the East Prussia Baltic region and probably the Ordovician (£3 zone) Bohemian Kalk of Karlstein in west- ern Czechoslovakia.

Angochitixa bifurcata Collinson and Schwalb, n. sp.

Figure 7; plate 2, figures 1-3

Diagnosis. — Chamber pyriform ; termi-

nated orally by long thin translucent sub- cylindrical collar at the end of a short flared neck ; broadly rounded aborally ; mouth simple ; chamber wall thin and translucent ; external surface of chamber covered with numerous fine bifid spines.

Remarks. — This species is known from numerous individuals in the Lower De- vonian Bailey formation in wells of south- ern Illinois. The holotype and the two fig- ured paratypes are preserved in white chert as natural cross sections. The holotype (pi. 2, fig. 3) is .12 mm. long and .05 mm. wide if the spines are disregarded. The spines average about .025 mm. long in the holo- type, and it is estimated that there are about 50 spines per individual in the species. A few short spines occur on the collar of the holotype and one paratype. The collar of the holotype is .037 mm. long and the aper- ture of the chamber .025 mm. in diameter. The collar is very slightly expanded orally and in outline appears to be an extension of the neck.

'^M^^:<!?:

Fig. 7. — Diagrammatic representation of Angochi- tina bifurcata n. sp., illustrating the shape of the spines and attachment of the collar, X665.

22

ILLINOIS STATE GEOLOGICAL SURVEY

Angochitina bifurcata more closely resem- bles A. capillata Eisenack from the Ordovi- cian Ostseekalk than any other species. The European species differs, however, in that it has no distinct collar and its spines are sim- ple and short. Lagenochitina sacculus is much like A. bifurcata but it is larger and possesses no spines. Likewise Lagenochitina baltica Eisenack is shaped like A. bifurcata but has no spines.

The species name bifurcata (Latin) means "forked" and refers to the bifurcate nature of the spines.

Occurrence. — Very abundant in the Lower Devonian Bailey formation in Shell Oil Co.-Ragan well 1, sec. 25, T. 2 S., R. 1 E., Jefferson Co., 111., between the depths of 3907 and 3910 feet; and in the F. Lyrler-Baysinger well 1, sec. 32, T. 10 S., R. 3 W., Jackson Co., 111., between the depths of 270 and 335 feet. All figured specimens came from the latter well ; the holotype (pi. 2, fig. 3) from between the depths of 315 and 320 feet and the figured paratypes from between 330 and 335 feet.

The species also occurs abundantly in loose blocks of rock believed to be Grand Tower limestone excavated for the founda- tion of an aerial pipeline crossing tower near the Devils Bakeoven in sec. 23, T. 10 S., R. 4 W., Jackson Co., 111.

Repository. — Illinois Geological Survey.

Angochitina flasca CoUinson and Schwalb, n. sp.

Figure 8; plate 1, figures 1-6; plate 2, figures 14 and 15

Diagnosis. — Chamber pyriform to sub- pyriform ; terminated orally by simple mouth at end of short neck; terminated ab- orally by broad slightly concave base, which has distinct papilla with external pit ; cham- ber walls moderately thick; exterior surface of chamber relatively smooth except for scattered short spines.

Remarks. — Angochitina flasca is found in great numbers in the Middle Devonian Clear Creek chert throughout the subsur- face of southern Illinois. The holotype (pi. 1, figs. 5 and 6) is a well-preserved moder-

FiG. 8 — Angochitina flasca n. sp. Diagrammatic cross section showing details of the lip and the aboral papilla, approx. X335.

ate-size individual .15 mm. in maximum di- ameter and .17 mm. long. The size range of the species is from about .10 mm. to .30 mm. in length. The diameter of the mouth of the holotype is about 1/3 the diameter of the chamber. Although it could not be demonstrated with certainty, the mouth ap- pears to have an oral diaphragm. The para- type illustrated in plate 1, figure 1, does not possess such a structure, but it does show that the lip is much thinner than the cham- ber wall and that the chamber wall is only moderately thick (about .01 mm.). Details of the aboral papilla are shown in figure 8. There is some variation in the general shape of A. flasca. Some individuals, such as the paratype shown on plate 1, figures 2-4, are more depressed than the holotype, and oth- ers, such as the one shown on plate 2, figure 15, are more elongate. Perhaps species should be erected for these variants, but we are reluctant to do so until we have studied a greater number of individuals.

In general size and shape A. fiasca is sim- ilar to L. elongatus, which is known from the Clear Creek chert in a single well in White County, 111. However, L. elongatus is only slightly flattened basally. The Eu- ropean species that most closely resembles A. flasca is the one from the Ordovician of Czechoslovakia that Eisenack (1934, p. 68) referred to Conochitina? cf. filifera. The European species probably belongs in

SYSTEMATIC PALEONTOLOGY

23

Angochitina, but it differs from A. flasca in that it has a flared neck and a large num- ber of spines.

The specific name flasca is Low Latin for "wine bottle" or "flask."

Occurrence. — Middle Devonian Clear Creek chert in the following wells : 1 ) Magnolia Petroleum Co.- Youngs well 28, sec. 20, T. 2 N., R. 2 E., Marion Co., 111., at depths between 2485 and 2490 feet; 2) Superior-Ford well C-17, sec. 27, T. 4 S., R. 14 W., White Co., 111., where the spe- cies is common to abundant at depths of 4995 to 5456 feet (fig. 3). The holotype shown on plate 1, figures 5 and 6, is from a depth of 5020 feet. The paratypes illus- trated on plate 1, figures 1-4, and plate 2, figures 14 and 15, are from a depth of 5051 feet; 3) Burr Lambert Co.-Hagler well 1, sec. 28, T. 10 S., R. 2 W., Jackson Co., 111., where the species occurs at depths be- tween 2485 and 2590 feet; and 4) Na- tional Assoc. Petroleum Co.-Handley well 1, sec. 26, T. 10 N., R. 7 E., Cumberland Co., 111., where a questionable occurrence of the species was noted at a depth of 3736 feet.

Repository. — Illinois Geological Survey.

the American species has fewer and much coarser spines.

The specific namt pusil la (Latin) means "small and insignificant."

Occurrence. — Middle Devonian Clear Creek chert in the Superior-Ford well C-17, sec. 27, T. 4 S., R. 14 W., White Co., Ill, between depths of 5020 and 5030 feet.

Repository. — Illinois Geological Survey.

Genus AcANTHOCHiTiNA Eisenack, 1931

Genotype: Acanthochitina barbata Eisenack

Figure 5E

Only the genotype is referred to this group of bluntly terminated spiny forms. The genus is known only from the Ordo- vician Ostseekalk of the Baltic region.

Family Conochitinidae Eisenack, 1931

Chitinozoans of a general tapered or con- ical shape are referred to this family. The greatest thickness is always near the aboral end. The family contains a number of forms that resemble the preceding Lageno- chitinidae but also contains forms similar to some of the Desmochitinidae.

Angochitina pusilla CoUinson and Schwalb, n. sp.

Plate 1, figures 20 and 21

Diagnosis. — Chamber pyriform ; termi- nated orally by simple mouth, no distinct neck ; rounded aborally ; chamber wall mod- erately thick and opaque ; exterior surface covered with scattered coarse spines.

Remarks. — All known representatives of this species are from the Clear Creek chert in the subsurface of White Co. in southern Illinois. The holotype (pi. 1, fig. 21) meas- ures only .08 mm. in diameter and .12 mm. in length, and the two paratypes are of the same size. In general shape and size A. pusilla closely resembles Angochitina bi- furcata although that species possesses a thin translucent chamber wall and numerous bifid spines. A. pusilla also closely resem- bles A. capillata Eisenack from the Ordo- vician Ostseekalk of the Baltic region but

Genus Conochitina Eisenack, 1931

Genotype: Conochitina claviformis Eisen- ack

Eisenack gave the Conochitina the same characteristics as the family, and to date 26 species have been assigned to the genus. Among these species there is great variation in size and shape, and we feel that the genus has become polymorphic to such an extent that it is of little taxonomic value. Accord- ingly, we are emending Conochitina to in- clude only slightly tapered, club-shaped chitinozoans. As thus defined, the following species are referable to the genus:

C. cactacea Eisenack — Ordovician of East Prussia Baltic region.

C. claviformis Eisenack — Silurian Grap- tolithengestein of Baltic region, Silurian of Montagne Noire in southern France, and Ordovician (Eg) of Lodenitz in western Czechoslovakia (Bohemia).

24

ILLINOIS STATE GEOLOGICAL SURFEY

C. micracantha Eisenack — Ordoviclan Ostseekalk of the East Prussia Baltic re- gion, the Ordovician Schiefergebirges of western Germany (Rheinland), and the Middle Silurian Racine formation of north- eastern Illinois.

C. primitiva Eisenack — Ordovician Schie- fergebirges of western Germany.

C. proboscifera Eisenack — Silurian of the Baltic region.

C. ? simplex Eisenack — Ordovician (?) of the East Prussia Baltic region.

C. stentor Eisenack — Ordovician of the East Prussia Baltic region and the Ordo- vician Schiefergebirges of western Germany.

C. tuba Eisenack — Silurian of the East Prussia Baltic region.

?C biconstricta Lange — Devonian of Parana, southern Brazil.

C. dactylus n. sp. — Middle Silurian of northern Illinois.

CoNOCHiTiNA DACTYLUS Collinson and Schwalb, n. sp.

Plate 2, figures 16-19

Diagnosis. — Chamber club-shaped with greatest diameter about one-third total length from aboral end, tapers slightly from greatest diameter both aborally and orally ; oral one-third of chamber nearly cylindri- cal ; aboral end broadly rounded ; terminated orally by very short thin translucent col-

lar; mouth simple; terminated aborally by relatively large papilla ; chamber wall mod- erately thick; external surface smooth.

Rejnarks. — This species occurs abundant- ly in the Middle Silurian Racine formation in one well in northeastern Illinois. The holotype (pi. 2, fig. 17) is a well-preserved, though distorted specimen .17 mm. in maxi- mum diameter and .47 mm. long. The mouth is estimated to have been about .06 mm. in diameter before distortion. The holotype retains remnants of a very short thin translucent collar, as do several of the paratypes.

C. dactylus is very closely related to the genotype C. claviformis, which is known from the Silurian of the Baltic region and southern France and questionably from the Ordovician of western Czechoslovakia. The only differences between the two species are that the genotype is slightly flared orally and possesses short fine processes about the mouth. C. dactylus is found associated in Illinois with C. micracantha Eisenack, but the latter species is differentiated by its flat base.

The name dactylus (Latin) means "growing like a finger."

Occurrence. — Interreef facies of the Mid- dle Silurian Racine formation in the Mul- ford Engineering Service-Thornton well, sec. 34, T. 36 N., R 14 E., Cook Co., 111., between depths of 120 and 160 feet.

Repository. — Illinois Geological Survey.

Explanation of Plate 1 All magnifications Xl35 except where otherwise noted.

Fjgs l_6 —Angochitina flasca Collinson and Schwalb, n. sp. 1, natural section of a paratype showing in- terior of chamber, wall thickness, and oral lip; 2-4, three vie^ys of a depressed paratype show- ing oral aperture, aboral papilla, and general shape, respectively.

7-15—Lagenochitina sphaerka Collinson and Schwalb, n. sp. 7, detail of the holotype showing finely tuberculate exterior surface, X205; 8, natural section of a paratype illustrating the oral dia- phragm and aperture; 9, lateral view of the holotype showing the distinct neckand remnants of an oral collar; 10, oblique aboral view of the holotype showing the aboral papilla and pit; 11, 12, oral and lateral views of a paratype; 13-15, lateral, oral, and opposite lateral views ot an'incomplete distorted paratype illustrating specific variation.

U-W—Lazenochitina bremcervkata Collinson and Schwalb, n. sp. 16, 17, lateral view of a small incom- plete paratype and oblique oral view of a small complete paratype; 18, 19, lateral views ot two crushed paratypes showing a common state of preservation for this species.

W 21—Angochitina pusilla Collinson and Schwalb, n. sp. 20, lateral view of the single paratype; ' lateral view of the holotype showing the incomplete neck and a few coarse spines.

Illinois State Geological Survey

K. I. 186, Platk 1

(ioLLiNsoN AM) S(;u\>Ar.B. I'alkozoic (^hitinozoa

Illinois State Geological Survey

K. I. 186, Plate 2

(>>LLINSO\ AM) SCHWALB. IV\l,EOZOI(: (^HITINOZOA

SYSTEMATIC PALEONTOLOGY

27

CONOCHITINA MICRACANTHA Eisenaclc

Plate 2, figures 20-22

Conochitina Tnicracantha Eisenack, 1931, Palaeontologische Zeitschrift, bd. 12, p. 84- 85, pi. 1, figs. 19-21; pi. 2, figs. 20-22; pi. 4, fig. 16. Conochitina Tnicracantha Eisen- ack, 1939, Senckenbergiana, bd. 21, p. 142, pi. A, fig. 114.

Diagnosis. — Chamber shaped like tapered rod or club with maximum diameter at aboral end and tapering slightly toward mouth; terminated orally by thin translu- cent collar ; terminated aborally by flat base in middle of which is a small papilla ; cham- ber wall moderately thick; external surface smooth with exception of fine basal spines.

Remarks. — This species is very abundant in one well in northeastern Illinois, where it was found in the Middle Silurian Racine formation. The species was first described from Ordovician strata of the East Prussia Baltic region by Eisenack, who gave the size range of the species as from .23 mm. to .36 mm. In length. Our specimens fall within that range. Eisenack did not describe the

type specimens as possessing collars, but he stated that they had appendages about the mouth. As many of our specimens have what we interpret to be irregular remnants of thin collars, we feel that these "appen- dages" may be the structures Eisenack de- scribed.

The basal spines on our Illinois specimens are very fine and short and are seen only with magnifications of lOOX or more. Most of our specimens are well preserved but somewhat distorted.

In addition to the Illinois and Baltic oc- currences of C. micracantha, the species is also known from the Ordovician Schiefer- gebirges of western Germany (Rheinland). The species is perhaps closest to C. prhni- tiva, also from the Schiefergebirges, but the latter does not possess spines. The basal flattening of C. micracantha differentiates it from C. dactylus.

Occurrence. — Interreef facies of the Mid- dle Silurian Racine formation in the Mul- ford Engineering Service— Thornton well, sec. 34, T. 36 N., R. 14 E., Cook Co., 111., between depths of 120 and 160 feet.

Repository. — Illinois Geological Survey.

Explanation of Plate 2

All magnifications X135 except where otherwise noted.

Figs. 1-3 — Angochitina bifurcata CoUinson and Schwalb, n. sp. 1, natural longitudinal section of a para- type with an incomplete collar; 2, natural transverse section of a paratype; 3, natural lon- gitudinal section of the holotype showing collar, neck, and spines. All X205.

4-6 — Ampiillachitina laguncula Collinson and Schwalb, n. sp. 4, lateral view of a distorted paratype; 5, lateral view of the holotype showing neck, collar, and several spines; 6, lateral view of a distorted paratype. All X205.

7-9 — Illichitina crotalum Collinson and Schwalb, n. sp. 7, slightly oblique lateral view of incom- plete holotype showing bell-shaped chamber and cylindrical neck; 8, 9, lateral views of dis- torted and incomplete paratypes, X205.

10 — Lagenochitina elongata Collinson and Schwalb, n. sp. Lateral view of the holotype showing large open rupture in the chamber wall.

11-13 — Lagenochitina brevicervicata Collinson and Schwalb, n. sp. 11, 12, lateral views of two small paratypes illustrating kinds of specific variation; 13, lateral view of the holotype which is slightly distorted.

14, 15 — Angochitina flasca Collinson and Schwalb, n. sp. 14, lateral view of a relatively long paratype; 15, aboral oblique view of a paratype showing relatively small papilla.

16-19 — Conochitina dactylus Collinson and Schwalb, n. sp. 16, lateral view of a crushed paratype showing undistorted aboral papilla; 17, lateral view of slightly crushed holotype with rem- nants of a collar at the oral end; 18, lateral view of small paratype; 19, lateral view of largest paratype.

20-22 — Conochitina micracantha Eisenack. 20, lateral view of specimen showing remnant of oral collar and aboral papilla; 21, lateral view of relatively complete undistorted specimen with remnants of oral collar; 22, lateral view of crushed specimen.

28

ILLINOIS STATE GEOLOGICAL SURFED

Genus Ampullachitina Collinson and Schwalb, n. gen.

Genotype: Ampullachitina laguncula Collinson and Schwalb, n. sp.

One group of chitinozoan species, which Eisenack referred to the genus Conochitbia, have certain common characteristics. They have a maximum diameter near the aboral end. From there they taper rapidly for less than half their total length, and the remain- ing length consists of a long cylindrical or subcylindrical neck. For this group of spe- cies, we are proposing the generic name Am- pullachitina. Ampullachitina laguncula , n. sp. from the Lower Silurian in the Superior- Ford C-17 well in southern Illinois is the genotype. Like the genotype, species re- ferred to this genus commonly possess spines on the aboral part of the chamber. The fol- lowing species should be referred to Ampul- lachitina.

A. ancyrea (Eisenack) — Silurian Chon- eteskalk of the East Prussia Baltic region.

A. diabolo (Eisenack) — Silurian of Bal- tic region, Ordovician (E2) at Kozel and Lodenitz in western Czechoslovakia, and Middle Silurian of the Montagne Noire in southern France.

A. fuugiformis (Eisenack) — Ordovician of the East Prussia Baltic region and Si- lurian e^ zone of Dlouha hora in western Czechoslovakia.

A. kuckersiana (Eisenack) — Ordovician Kuckers'schen Stufe of the East Prussia Baltic region and the Middle Silurian of the Montagne Noire in southern France.

A. metancyrea (Eisenack) — Silurian Bey- richienkalk of the East Prussia Baltic re- gion.

A. pistilliformis (Eisenack) — Silurian Choneteskalk of the East Prussia Baltic re- gion.

A. protancyrea (Eisenack) — Ordovician Ostseekalk of the East Prussia Baltic re- gion.

A. spinosa (Eisenack) — Silurian Crinoi- denkalk of the East Prussia Baltic region.

Ampullachitina laguncula Collinson and Schwalb, n. gen., n. sp.

Figure 9 ; plate 2, figures 4-6

Diagnosis. — Chamber subconical; termi- nated orally by slightly expanded thin trans- lucent collar at end of long cylindrical neck ; terminated aborally by flat base fringed with few fine spines; chamber wall thin and translucent; external surface generally smooth.

Remarks. — Four rather poorly preserved individuals were recovered from hydro- chloric-acid-insoluble residues of Lower Si- lurian dolomite from the Superior-Ford C-17 core (fig. 3). The least distorted and most complete specimen (plate 2, fig. 5) is designated the holotype; it is .075 mm. in maximum diameter and .12 mm. long. The diameter of the neck is about 1/3 that of the chamber, and the diameter of the collar is 1/2 that of the chamber. The neck and collar are .025 and .037 mm. long, respec- tively. Although most of the basal spines of the holotype were broken during study of the specimen (see fig. 9 for restoration), two are still preserved; they are short, fine, and slightly curved.

Fig. 9. — Diagrammatic representation of Ampulla- chitina laguncula n. gen., n. sp. showing the general shape of the genus, attachment of the collar, and basal spines, X580.

SYSTEMATIC PALEONTOLOGY

29

Ampullachitina laguticula closely resem- bles A, diabolo (Eisenack), which is known from the Silurian of the East Prussia Baltic region, the Ordovician of western Czecho- slovakia, and the Middle Silurian of south- ern France. The European species has very coarse hollow spines which form extensions of the chamber. Also, A. diabolo is broadly rounded aborally rather than flattened. The specific name laguucula (Latin) means "lit- tle flask."

Occurrence. — Lower part of the Lower Silurian Sexton Creek formation in the Su- perior-Ford well C-17, sec. 27, T. 4 S., R. 14 W., White Co., 111., between depths of 6065 and 6070 feet.

Repository. — Illinois Geological Survey.

Genus Illichitina Collinson and Schwalb,

n. gen.

Genotype: Illichitina crotalum Collinson

and Schwalb, n. sp.

Like Ainpullachitina, Illichitina is pro- posed for a number of species assigned to Conochitina by Eisenack but which do not belong to that genus as emended in this re- port. Illichitina includes all species that possess a shape reminiscent of a bell with the large end closed and the small end open, that is, with the maximum diameter at the aboral end, tapering rapidly from that diam- eter for a very short distance to form a slight basal flare, then tapering gradually to a cylindrical neck, but with a slight infla- tion near the midlength. The species vary greatly in their proportions, some being very elongate, others short. A few species have a fringe of basal spines. /. crotalum n. sp. from the Lower Silurian Sexton Creek for- mation in the Superior-Ford well C-17 is the genotype.

The genus Illichitina is named for the State of Illinois.

The following species are referable to Illichitina.

I. calix (Eisenack) — Ordovician Ostsee- kalk and Ordovician (Bo and Bo or C zones) of East Prussia Baltic region; Or- dovician Schiefergebirges of western Ger- many (Rheinland).

/. canipanulaefor?nis (Eisenack) — Silu- rian Choneteskalk of the East Prussia Bal- tic region ; the Ordovician Schiefergebirges of western Germany (Rheinland) ; the Or- dovician at Sarka-Vokovice (D^^ and D^2 zones) and Prag along the Wilson-Bahnhof (D;//2 zone) in western Czechoslovakia (Bohemia).

I. cervicornis (Eisenack) — Silurian? sandstone of East Prussia Baltic region.

I. coronata (Eisenack) — Ordovician Ost- seekalk of East Prussia Baltic region.

/. elegans (Eisenack) — ^Silurian ? sand- stone of East Prussia Baltic region.

Illichitina crotalum Collinson and Schwalb, n. gen., n. sp.

Plate 2, figures 7-9

Diagnosis. — Chamber subconical with maximum diameter at base, tapers rapidly toward the oral end, very slightly flared at aboral end; terminated orally by short thin translucent collar at end of short cylindrical neck; terminated aborally by flat base; chamber wall rather thin, brown, and trans- lucent; external surface very finely tuber- culate.

Remarks. — The four known representa- tives of this species were found in hydro- chloric-acid-insoluble residues from the Lower Silurian Sexton Creek formation of southern Illinois. The holotype (plate 2, fig. 7) is well preserved, although both the collar and base are incomplete. The speci- men is .15 mm. in maximum diameter and .18 mm. long, and the neck is about .012 mm. long and .047 mm. in diameter. The mouth of the chamber appears to be simple and smooth. The collar appears to have been about .015 mm. long. There is no evidence of a diaphragm.

Each of the three paratypes is distorted, incomplete, and smaller than the holotype, averaging about .12 mm. in length. The species was found associated with Ampulla- chitina laguncula and numerous scoleco- donts. The species closely resembles /. cam- panulaeformis (Eisenack) from the Silurian of the East Prussia Baltic region and the Ordovician of Germany and Czechoslo-

30

ILLINOIS STATE GEOLOGICAL SURFEY

vakia. However, the European species has a relatively long neck and a distinct basal flare.

The specific name crotalum (Latin) means "bell."

Occurre?ice. — Common in the lower part of the Lower Silurian Sexton Creek forma- tion in the Superior-Ford well C-17, sec. 27, T. 4 S., R. 14 W., White Co., 111., be- tween depths of 6065 and 6070 feet.

Repository. — Illinois Geological Survey.

Genus Rhabdochitina Eisenack, 1931

Genotype: Rhabdochitina magna Eisenack

Figure 51

This genus was given wide limits by Eisenack. It includes species that are very long, tubular, and terminated in almost any manner. Some species included in the genus by Eisenack have basal bulbs, others arc broadly rounded or flat, and some have a basal flare. In addition to the genotype, which is from the Ordovician Ostseekalk of the East Prussia Baltic region, the fol- lowing species have been assigned to the genus.

R. canna DeFlandre — Middle Silurian limestone of the Montagne Noire in south- ern France.

R. conocephala Eisenack — Silurian Kuck- ers'schen Stufe of the East Prussia Baltic region.

R. ? ininnesotensis Stauffer — Middle Or- dovician Decorah formation of southern Minnesota.

R. cf. pistilUforjnis Eisenack — Ordivi- cian (D^]^ zone) of western Czechoslo- vakia (Bohemia).

R. pistillifrons Eisenack — Ordovician Schiefergebirges of western Germany (Rheinland).

R.^ taenia Eisenack — Silurian? of East Prussia Baltic region.

Rhabdochitina ? minnesotensis Stauffer

Figure 10

Diagnosis. — Of this species Stauffer wrote (1933, p. 1209) "Body elongate, subcylin-

FiG. 10. — The holotype of Rhabdochitina ? minne- sotensis Stauffer from the Middle Ordo- vician Decorah formation of southern Minnesota. Adapted from Stauffer (1933), X82.

drical in outline, although it tapers slightly towards the proximal end, suggesting the outline of a baseball bat. Terminal, or dis- tal, end is smooth and rounded, but some specimens show a small elevation with a flattened apex. Proximal end is slightly smaller and probably had some means of at- tachment. Surface of the test is smooth, shiny, and black."

Remarks. — Although we have not seen the types of this species, we are including the description for the sake of completeness.

Occurrence. — "Lower part of the De- corah (Middle Ordovician) shale, 5 feet above the base of the formations. Ford Bridge, Minneapolis, Minnesota. In the shale just above the 'marble layer,' 41/2 f^^t above the base of the Decorah shale, Lieb Quarry, Faribault, Minnesota."

SYSTEMATIC PALEONTOLOGY

31

Holotype. — Geological Museum, Univer- sity of Minnesota, B4233.

Family Desmochitinidae Eisenack (1931)

This family includes bubble- or flask- shaped individuals commonly united to form chains. The most-aboral chamber was sug- gested by Eisenack to be the parent of the succeeding individuals that arose by budding from the parent. Since little is actually known of the Desmochitinidae, w^e are using the term chain to designate two or more in- dividuals that are united. Individuals of most species are interconnected by a basal disc to which we are applying the term flange. The flange is attached to the cham- ber by a rod-like process which Eisenack designated the copula. Some species, how- ever, possess only a thick copula and no flange. Others have neither flange nor cop- ula.

Genus Desmochitina Eisenack, 1931

Genotype: Desmochitina nodosa Eisenack

Figure 5F

Eisenack described this genus as having the same characteristics as the family. It and Conochitina are the two most common genera known. In addition to the genotype which is known from the Silurian of the East Prussia Baltic region the foHowing species have been referred to Desmochitina:

D. amphorea Eisenack — Silurian? of East Prussia Baltic region.

Z).? bohemica Eisenack — Upper Silurian of western Czechoslovakia (Bohemia).

D. cingulata Eisenack — Silurian ? of the East Prussia Baltic region.

Z).? cocca Eisenack — Ordovician Ostsee- kalk? of East Prussia Baltic region.

D.? complanata Eisenack — Ordovician? of East Prussia Baltic region.

/).? erinacea Eisenack — Ordovician (B3 or C zone) of East Prussia Baltic region.

D. erratica Eisenack — Silurian Grapto- lithengestein of the East Prussia Baltic re- gion.

D.? gigantea Eisenack — Ordovician (D^i zone) of Sarka in western Czechoslo- vakia (Bohemia).

D. margaritana Eisenack — From the Si- lurian? of the East Prussia Baltic region.

Z).? minor Eisenack — Ordovician Ostsee- kalk of East Prussia Baltic region; Ordo- vician (D;//i and V>^p2. zones) at Sarka and Svota Dobrotina in western Czechoslovakia (Bohemia) ; Ordovician Schiefergebirges of western Germany (Rheinland).

D. ex. af¥. minor Eisenack — Ordovician Schiefergebirges of western Germany (Rheinland).

D. poculum n. sp. — Lower Devonian Bai- ley formation of southern Illinois.

D. rhenana Eisenack — Ordovician Schief- ergebirges of western Germany (Rhein- land).

Z).? lima Eisenack — Silurian? of East Prussia Baltic region; Silurian (E^ or Ea zone) of western Czechoslovakia (Bohe- mia) ; Silurian of the Montagne Noire of southern France.

2).? sp. A. Eisenack — Ordovician (D^/.^ zone) of Sarka in western Czechoslovakia (Bohemia).

D.? sp. B. Eisenack — Ordovician (D^g zone) of Svota Dobrotina, western Czecho- slovakia (Bohemia).

Desmochitina poculum Collinson and Schwalb, n. sp.

Figure 11

Diagnosis. — Chamber subspherical, de- pressed; terminated orally by simple mouth; terminated aborally by flange at end of short copula; chamber wall thin and opaque; external surface smooth (fig. IIC).

Remarks. — Only three representatives of this species are known, and all are preserved as natural cross sections in white chert. All came from the Lower Devonian Bailey for- mation in a well in southern Illinois. Two of the specimens are single individuals and the third is a somewhat distorted chain of two complete chambers and a portion of a third {fig. IIA). The larger of the two single individuals is designated the holotype (fig. IIB) and it is .07 mm. in maximum

32

ILLINOIS STATE GEOLOGICAL SURVEY

Fig. 11. — Desmochitina poculum n. sp. (A) repre- sents a natural longitudinal section of an incomplete chain showing two complete chambers and part of a third, X305; (B) represents a natural longitudinal section of the holotype, X390; (C) is a diagram- matic reconstruction based on the holo- type and two paratypes, approx. X300.

diameter and .07 mm. long. The copula is .012 mm. long and the flange is .025 mm. in diameter. The diameter of the mouth is about 1/3 that of the chamber. Several chains of distorted and unidentifiable rep- resentatives of Desmochitina are associated with D. poculum along with great num- bers of Angochitina bij areata. D. poculum is similar to D. jiiargaritana Eisenack from the Silurian? of the East Prussia Baltic re- gion in that neither species possesses a neck. However, the chamber of the European spe- cies is not depressed and its copula is rela- tively long.

The specific name poculum (Latin) means "goblet" or "bowl."

Occurrence. — Lower Devonian Bailey formation in F. Lyrler-Baysinger well 1, sec. 32, T. 10 S., R. 3 W., Jackson Co., 111., between depths of 270 and 275 feet.

Repository. — Illinois Geological Survey.

Desmochitina sp. Figure 12

Several representatives of Desmochitina have been identified although none are suf- ficiently well preserved to be diagnosed spe- cifically. All are preserved in white chert from the Lower Devonian Bailey formation in the following wells: 1) Shell Oil Co.- Ragan well 1, sec. 28, T. 2 S., R. 1 E., Jef- ferson Co., 111., between depths of 3907 and

3910 feet; 2) F. Lvrler-Baysinger well 1, sec. 32, T. 10 S., R. 3 W., Jackson Co., 111., between depths of 270 and 275 feet.

Repository. — Illinois Geological Survey.

Genus Mirachitina Eisenack, 1931

Genotype : Mirachitina quadrupedis Eisenack

Figure 5D

This genus deviates from normal chitino- zoan symmetry and therefore is included here with some doubt. The genus is mono- specific and, as interpreted by us, the geno- type M. quadrupedis Eisenack consists of a main cylindrical chamber which is rounded aborally and possesses a small papilla. At the oral end of the main chamber, four sub- sidiary chambers are attached at about 120° to the axis of the main chamber and at 90° to each other. The genotype is from Silurian? limestone of the East Prussia Baltic area.

Genus Parachitina Eisenack, 1937

Genotype : Parachitina curvata Eisenack

Figure 5G

This genus, like Mirachitina, departs from normal chitinozoan symmetry and is included here with uncertainty. The genus is monospecific and includes U-shaped speci- mens which have an inflated abdomen and two tapering shanks which end bluntly. The genotype is from the Silurian ? of the East Prussia Baltic region.

Fig. 12.

-Natural longitudinal section oi Desmochi- tina sp. from the Lower Devonian Bailey formation of southern Illinois, X320.

REFERENCES

33

REFERENCES

Clark, G. L., and Smith, A. F., 1936, X-ray dif- fraction studies of chitin, chitosan, and de- rivitives: Jour. Phys. Chem., v. 40, p. 863-879.

Cloud, P. E., 1955, Physical limits of glauconite: Bull. Am. Assoc. Petroleum Geologists, v. 39, p. 484-492.

Cooper, C. L., 1942, North American Chitinozoa (abst.): Bull. Geol. Soc. Am., v. 53, p. 1828.

CusHMAN, J. A., 1950, Foraminifera: Cambridge, Harvard Univ. Press, 4th ed., p. 1-605.

DeFlandre, Georges, 1942, Sur les microfossiles des calcaires siluriens de la Montagne Noire, les chitinozoaires (Eisenack): Acad. Sci. Paris, C. R., t. 215, p. 286-288.

, 1945, Microfossiles des calcaires siluriens

de la Montagne Noire: Ann. Paleont., t. 31, p. 39-75, pis. 1-3.

., 1952, Protistes: in Traite de Paleontologie,

ed. J. Piveteau: Paris, Masson, t. 1, p. 327-329.

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