. DEPARTMENT OF THE INTERIOR

UNITED STATES GEOLOGICAL SURVEY

GEORGE OTIS SMITH, DIRECTOR

598

FAUNAS OF THE BOONE LIMESTONE

ST. JOE, ARKANSAS

BY

GEORGE H. GIRTY

WASHINGTON

GOVERNMENT PRINTING OFFICE 

1915

CONTENTS.

Page.

Lower part of the Boone limestone......................................... 5

Introduction.......................................................... 5

Coelenterata........................................................... 7

Bryozoa............................................................... 8

Brachiopoda.........,................................................. H

Pelecypoda .......................................................... 20

Gastropoda............................................................ 21

Cephalopoda.......................................................... 22

Trilobita............................................................. 22

The St. Joe limestone member ............................................ 24

Introduction.......................................................... 24

Coelenterata........................................................... 28

Echinoderrnata....................................................... 30

Bryozoa............................................................... 30

Brachiopoda.......................................................... 33

Gastropoda............................................................ 42

Index................................................................... 49

ILLUSTRATIONS.

Fagc. 

PLATES I-11.T. Fossils from the Boone limestone ......................... 44, 46, 48

3

FAUNAS OF THE BOOM LIMESTONE AT ST. JOE,

ARKANSAS.

By GEORGE H. GIRTY.

LOWER PART OF THE BOONE LIMESTONE.

INTRODUCTION.

The Boone limestone takes its name from Boone County, in northern Arkansas, an area approximately coextensive with the Harrison 

topographic sheet of the United States Geological Survey. The name, 

seems to have been used in several reports prepared simultaneously 

by members of the Arkansas survey, but it first appeared in a report 

by Penrose, published in 1891.1 The formation in Arkansas has been 

described only in general terms and no type section has been given.

As the term is at present used by the United States Geological Survey the Boone limestone includes all the lower Mississippian rocks of 

northern Arkansas and southern Missouri, comprising equivalents of 

the Kinderhook, Burlington, and Keokuk formations farther north. 

The name has sometimes been employed to the exclusion of certain 

basal beds supposed to represent the Kinderhook group, and on the 

other hand it may well be that authors have locally included under 

it remnants of formations later than the Keokuk.

The upper beds of the Boone limestone in the Joplin district contain what may be called the Productus magnus fauna. This fauna 

has always been accepted as of Keokuk age, and consequently I have 

contended that no part of the Boone, properly so called, was younger 

than the Keokuk. Prof. Weller tells me, however, that he has recently obtained satisfactory evidence that the age of the Productus 

magnus fauna is not Keokuk but Warsaw. That he is correct in this 

. conclusion is indicated by evidence that came independently into my 

hands last autumn, and consequently it now .seems necessary to 

regard the Boone limestone as ranging in age from Kinderhook (Fern 

Glen) to Warsaw.

The rocks of the Boone extend into northern Missouri, Iowa, and 

Illinois, but the application of the name is restricted to areas in 

southern Missouri, northern Arkansas, and adjacent parts of Kansas 

and Oklahoma. In this region the Boone is composite, here and 

there differentiated into members which appear, however, to be 

more or less regional in their distribution. One of the most widely

i Arkansas Oeol. Survey Ann. Kept, for 1890, p. 120,1891.
6 FAUNAS OF THE BOONE LIMESTONE AT ST. JOE, AKK.

recognized of the subdivisions of the Boone is the St. Joe limestone 

member, which is typically exposed at St. Joe, Searcy County, Ark., 

and which has been identified over much of northern Arkansas and also 

in northeastern Oklahoma. This is by definition the basal member 

of the Boone, and it has been correlated by Prof. Weller, it appears 

correctly, with the Fern Glen limestone member of the Kinderhook formation. Some evidence exists that the St. Joe is separated from the 

overlying portions of the Boone by an unconformity,1 though its 

apparent absence in some sections may be due to nondeposition. -In 

the Joplin region, where the section has been so much more thoroughly 

studied that it has in a measure usurped the function of the typical 

section, the Boone has been divided into several members. At the 

base are as much as 100 feet of thin, impure shaly and cherty limestones, occupying in part the position of the St. Joe limestone, but 

not having the St. Joe lithology. These are overlain by the Grand 

Falls chert member 40 or 50 feet thick. The upper 200 feet, mainly 

of pure limestone, is divided midway by the Short Creek oolite member. These subdivisions can not be traced into more remote regions, 

and others take their places.

In its fauna also the Boone is not a unitary but a composite body. 

Several fairly well differentiated faunal facies can be recognized in it, 

though these, like the lithologic subdivisions, are perhaps somewhat 

regional in their development.

Thus, while the Boone has been treated as a unit it has long been 

known that it was not such, but could probably be satisfactorily dissected into several constituents. That it has not been actually so 

dissected is, as I understand it, largely a practical question. Conditions are such that for defining and tracing the different members a 

close and constant paleontologic check would be necessary, and the 

end to be gained has not seemed to justify the effort when so many 

more desirable ends were demanding attention.

It is with the purpose, however, of making a small contribution to 

the investigation of the Boone problem that the present paper is 

written. I have described in more or less detail (pp. 25-26) the fauna of 

the St. Joe limestone as it occurs in a railroad cut 1£ miles west of the 

depot at St. Joe, Ark. The present paper similarly describes a fauna 

which was found at the same locality near the base of the overlying 

portion of the Boone^ within 10 feet of the lithologic top of the St. Joe. 

Small in scope though the present study be, if a sufficient number of 

similar papers were at hand the Boone could be analyzed in all its 

essential relations, even if it still seemed desirable for convenience 

to .treat it as a single formation.

Of the character and correlation of this small but interesting fauna 

I propose to say but little at present. It possesses a somewhat novel

___________________________________________________________________________________

1 Hopkins, T. C., Arkansas Geol. Survey Ann. Kept, for 1890, p. 254,' 1893.
LOWER PART OF THE BOONE LIMESTONE. 7

facies, owing to the presence of a considerable number of new species 

and to the association of types whose ranges have not heretofore 

been known to overlap. Of the 32 species which I have been able to 

identify in this fauna 8, or 25 per cent, are described as new, and several others are almost certainly new, but are represented by material 

so indifferent that the introduction of a new name does not seem warranted. Furthermore, a few types suggesting a Keokuk fauna, such 

as a new species of Hernitrypa, together with Reticularia pseudolineata, 

Amplexusfragilis, and Spirifer suborbicularis (all three of which, however, occur also in the Burlington), are associated with forms like 

Lepts&na analoga and ProducteUa concentrica, which bespeak a lower 

horizon. On the whole the facies may provisionally be regarded 

as belonging in the Burlington, where indeed the stratigraphic relations would also seem to place it.

From the St. Joe fauna, which preceded it, this marks a distinct 

and indeed a rather abrupt change. The St. Joe collections from this 

locality furnish 40 species and the present fauna comprises 32. Of 

these 72 species only 5 (Cystodictya Uneata, Leptxna analoga, ProducteUa concentrica?, Spirifer grimesi, and Clioihyridina Tiirsuta? or 

roissyif) appear to be common to both faunas. I fully 6xpect that 

more complete data based upon more widely distributed collections 

would show a closer relationship, but even then the faunal change 

would probably remain noteworthy.

The fauna described in this paper has been recognized in other 

collections from the Boone, and it probably has a fairly wide distribution. Until, however, those collections are carefully studied and 

the correlation verified it will be best to withhold a specific statement in regard to its geographic extent.

The two papers comprised in this bulletin were submitted for publication in the spring of 1914. They were consequently prepared 

without the aid of Prof. Weller's monograph on Mississippian Brachiopoda, copies of which did not reach Washington until the following 

November. Had this valuable work been available, some of the 

things which I have written would have been omitted as superfluous, 

and some of the species would have been differently identified.

C(ELENTERATA.

AMPLEXUS FKAGILIS White and St. John.

As represented in my collection this form consists of nearly straight 

stems which have -a regularly cylindrical shape and a diameter not 

greater than 14 millimeters. Only three fragments have been obtained, and they do not show satisfactorily certain characters, especially the range of variation. The septa, which are very short, 

number about thirty, though it has not been practicable to count 

them accurately. The central portion of the corallum, owing to the
8 FAUNAS OP THE BOONE LIMESTONE AT ST. JOE, ARK.

shortness of the septa, is very large, and is divided into chambers >. 

by regularly arranged tabulse which are nearly flat, horizontal, and 

situated about 5 to 6 millimeters apart. The surface is marked by 

coarse striae and also by finer intermediate ones. There are likewise 

obscure longitudinal markings connected with the septa.

A.fragilis was described from the Keokuk limestone. It has been 

cited also from the Burlington limestone, and the Burlington type t 

described by Miller as A. licostatus has been regarded as a synonym. ' 

In view of their stratigraphic position the fossils under consideration 

should be most like Miller's A. l)icostatus, but they are considerably 

smaller with rather fewer septa and somewhat more regular tabulae. 

It is a little uncertain, therefore, whether they are really identifiable 

with A.fragilis; if not, they are at least closely related. ^

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark. 

BRYOZOA. >

CYSTODICTYA LINE AT A Ulrich.

This is a rather abundant species, but the specimens, which are 

broken out of a limestone matrix, are probably a little exfoliated, 

such characters as the peristomial developments having suffered 

especially. The stipes have a width of 4 to 5 millimeters, a small 

thickness, gently convex sides, and sharp edges. One specimen 

shows branching at intervals of 9 millimeters, or more correctly the 

lower division seems to be in the nature of a branch and the upper 

a bifurcation. Other fragments are much longer than this without 

showing subdivision.

The surface is marked by longitudinal ridges and grooves of about v 

equal size. The zooacia are situated on the ridges and are thus conspicuously arranged in longitudinal rows, of which there are eight or 

nine. An oblique arrangement is also conspicuous in most specimens, 

especially toward the margins, where obscure ridges are sometimes 

produced in this way. Marginally the apertures appear to be larger 

and the longitudinal ridges rather more indistinct. As presented in v 

a probably exfoliated condition the apertures usually appear to be 

nearly circular with raised peristomes, but in places a lunarium is 

indicated and a trefoil-shaped aperture. About four apertures occur 

in 2 millimeters longitudinally.

This is almost certainly the form which Prof. Weller identified as 

C. lineata in the fauna of the Fern Glen limestone member of the > 

Kinderhook formation, and it probably also occurs in the St. Joe , 

limestone member of the Boone limestone, though the St. Joe specimens are too poor for an accurate determination of this point.

Horizon and locality. :Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark.
LOWER PART OF THE BOONE LIMESTONE. 9

FENESTELLA RUDIS Ulrich?

The largest and most satisfactory of the group of specimens included under this title shows a large, gently curved zoarium which 

apparently has the zooecial apertures on the outer side. It is much 

exfoliated and can be only partly described. Seven or eight branches 

occur in 5 millimeters and from four to four and one-half fenestrules 

longitudinally in the same distance. The growth is regular. The 

branches are slender, straight, slightly narrower than the fenestrules 

and slightly larger than the dissepiments. The fenestrules are elliptical with a length about one and one-half times their width. The 

backs of the branches are finely striated. Three zooecial apertures 

occur opposite each fenestrule, with or without an additional one 

opposite the dividing dissepiment! The other characters are obscured by exfoliation.

In all the characters preserved this form agrees very closely with 

the Keokuk species F. rudis.

Horizon, and locality. Boone limestone, in beds overlying the 

St. Joe limestone member, St. Joe, Ark.

FENESTELLA sp. a.

Of this type our collection contains two specimens, both on the 

same slab, both showing the reverse side, and both more or less 

deeply exfoliated. The frond appears to have been large and nearly 

flat and the growth very regular. Ten branches occur in 5 millimeters, and five and a half to six fenestrules longitudinally in the 

same distance. The branches are slender and straight, apparently 

finely striated on the back. On the obverse the dissepiments appear 

to be narrow (about one-half the width of the branches) and to 

make rectangular fenestrules, and on the reverse they appear to be 

broader and to make elliptical fenestrules. The fenestrules are elongated, their length being about one and one-half times their width or 

a little more. They are slightly wider than the branches.

The apertures occur about four to a fenestrule, sometimes three 

opposite the fenestrule and -one opposite the dissepiment. The characters of the peristome and of the carina are not shown.

This species resembles F. rudis and F. herrickana but is rather 

more finely constructed than either. It is also related to F. cavernosa. 

So far as examined, however, there is no described species with 

which it agrees in all particulars.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark.

FENESTELLA sp. &, c, d, and e.

The presence of four other species of Fenestella is indicated in the 

collection by fragments so small that a description of them would
10 FAUNAS OF THE BOONE LIMESTONE AT ST. JOE, ARK.

hardly be worth, while. They are all rather finely reticulate forms ^ 

varying chiefly in proportional measurements with nothing otherwise 

very distinctive, so far as known.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member,"St. Joe, Ark.

POLYPORA n. sp,

A single specimenx (showing the reverse side) of what is clearly a 

new species of Polypora occurs in the collection, but owing to the 

insufficiency of data it seems undesirable to introduce a new name 

in this place. The type is distinguished by its largely and loosely 

reticulate growth with relatively slender branches and dissepiments. 

The growth is in fact rather irregular, the branches dividing fre- 4 

quently and enlarging considerably before division. The slender 

dissepiments, about half as wide as the branches, occur at irregular 

intervals, leaving subquadrate fenestrules, all longer than wide and y 

some relatively much longer than others.

The backs of the branches are covered with very fine discbntinuous or inosculating striae and by rather numerous papillae. ^

It is, of course, of the obverse face that our information is especially 

deficient, and of this I am able to state only that the zooecia appear 

to be arranged in three rows.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark.

HEMITRYPA n. sp.

The only specimen of this singular species is a slender, gradually > 

enlarging, almost cylindrical zoarium, which has a length of nearly 

50 millimeters and still is incomplete at the lower if not also at the

upper end, where it has a diameter of only 8 millimeters. The 

zoarium is poriferous on the outer side. Only the superstructure 

is presented to view, and of that only the inner surface. This 

shows a series of equal circular apertures, very regularly arranged in >- 

longitudinal rows, the branches and dissepiments (to adopt the 

terms used for analogous structures in the true zoarium) being 

exactly equal save only that the alternate branches are slightly 

larger, so that the apertures are more or less clearly grouped in 

double series. The longitudinal divisions, or branches, are of course 

continuous, and the transverse divisions, or dissepiments, are dis- { 

continuous. Seven apertures occur in 2 millimeters longitudinally. ^

As already noted, no data relating to the inhabited portion of the f 

zoarium can be given. }-.

If this specimen is at all normal it is clearly a new species, distinguished, if by nothing else, by its singular manner of growth. 

Corresponding structural differences, however, would doubtless be >- 

found in the complete specimen and indeed are already shown or
LOWER PART OF THE BOONE LIMESTONE. 11

suggested by the very regular arrangement of the openings in the 

superstructure and by their circular shape.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark.

BBACHIOPODA.

LEPT^NA ANALOGA Phillips.

A single fragmentary specimen represents this type, but its relationship is unmistakable.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark.

CHONETES ORNATUS var. ARKANSANUS n. var. 

Plate I, figures 4,4a.

Shell very small, transverse, somewhat extended at the hinge line, 

rather inflated centrally, with strongly depressed ears and incurved 

beak. Surface marked by relatively coarse, strongly elevated lirse, 

about four in 1 millimeter, crossed by very fine regular concentric 

lirse.

This form is very similar to C. ornatus Shumard, of which it might 

be considered a small variety. The high convexity indicates that 

the specimens are mature, and in spite of their very much smaller 

size they have costae of about the same absolute size as Shumard's 

species and therefore relatively .very much coarser. The concentric 

lirae are, on the other hand, actually much finer, though possibly not 

finer in proportion to the size of the shell. They are, however, much 

finer in proportion to the size of the costse. The shape is also somewhat more transverse and more extended at the hinge line than is 

the case in typical C. ornatus.

In this connection it may be proper to restrict C. ornatus to the 

form which occurs in the Louisiana ("Lithographic") limestone at 

Louisiana and Hannibal, Mo. It is probable that Shumard's type 

specimen came from that region and that formation. He cites C. 

ornatus not only from there, however, but also from the Chouteau 

limestone in Cooper County and elsewhere, but it is a little improbable that the form was the same in both places.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark.

PRODUCTELLA CONCENTRICA Hall.

Plate I, figures 3-3b.

This species is represented by two specimens, both of which are 

very small but, judged by their convexity, are mature or nearly so. 

The width is only about 5 millimeters. The convexity is fairly 

strong, rather narrowed across the top transversely.
12 KAUNAS OF THE BOONE LIMESTONE AT ST. JOE, ARK:

The surface is nearly smooth, with almost invisible growth lines 

and a few large incremental striae. There is also evidence of a few 

spines that spring from the surface without much development of a 

prominence or spine base.

This is hardly the typical form of P. concentrica (which shows, 

however,/many modifications both in size and markings), for it is 

much smaller and lacks the strong concentric wrinkles and elevated 

spine bases, shown in most specimens of. concentrica, which tend to 

produce costse or plications toward the front of the shell.

The synonymy of this species offers some difficulty. On Plate VII 

of his Iowa report 1 Hall figures two specimens, one as Productus shumardianus and one as P. concentricus. Both appear to have been 

found at Burlington, and both almost certainly represent the same 

species, the one (P. concentricus) being based on a dorsal valve of the 

other. Both species are described as new in the work mentioned. 

Hall also figures another specimen of P. stiumardianus from another 

locality (Clarksville ?) and probably belonging to another species.2 

I propose to restrict the name shumardianus to the latter form and 

to use P. concentricus for the two Burlington specimens (one figured 

as P. shumardianus) represented on Plate VII. In connection with 

this proposal to divide P. shumardianus attention may be called to 

Hall's footnote under P. pyxidatus,3 which would be much more 

appropriate if it were really intended to refer to P. sliumardianus, 

since Hall records no specimens of P. pyxidatus from Burlington 

either in text or plates. Hall makes another obvious error under 

P. sliumardianus in referring to figure 1 of Plate VII instead of figure 

2. I regard P. cooperensis, which was described subsequently to P. 

concentricus, as belonging to the same species.

These small shells are very suggestive of Productus indianensis, 

from which they differ in having smaller and less numerous spines.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark.

PRODUCTELLA SEMICOSTATA n. sp. 

Plate I, figures 6-6d, 7-7c.

Shell small, transverse, semicircular or subquadrate in outline. 

Ventral valve rather strongly arched, not greatly produced anteriorly. Dorsal valve planate over the visceral region, more or less 

geniculate about the margin. Ears small, quadrate; depressed in 

the ventral valve.

In the ventral valve the posterior portion is devoid of costse, but 

the anterior portion is divided by radial grooves or striae into a 

number of relatively broad, flat ribs of very large size for a small 

shell. A few somewhat elongated spine bases are developed on the

> Geol. Survey Iowa Kept., vol. 1, pt. 2,1858. 2 Idem, PI. Ill, fig. 9. " Idem, p. 499.
LOWER PAET OF THE BOONE LIMESTONE. 13

posterior portion, especially toward the points where the costae are 

initiated, but they are not connected with the formation of the 

costae, being much narrower. The posterior part is also marked by 

fine microscopic incremental striae and by rather fine, somewhat 

irregular concentric wrinkles. Over the costate portion these markings are replaced by fine, regular, concentric lirae, finer than the 

wrinkles and coarser than the incremental markings of the posterior 

area. The dorsal valve has a corresponding sculpture but in reverse, 

so that a mold of the dorsal exterior corresponds in points of sculpture with the exterior of the ventral valve.

This form is very closely allied to P. concentrica and perhaps is 

only a variety of it. The specimens seen, however, differ in being 

much smaller than the average specimen of P. concentrica and more 

persistently marked by costae which are more regular, more large, 

and usually more distinct.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark..

PRODUCTELLA PATULA n. sp.

Plate I, figures 1-lb, 2.

Shell rather large, transverse, low and spreading. Dorsal and 

ventral valves similar in configuration, save that the ventral is more 

convex and has a more prominent beak and umbonal region.

The surface is marked by fairly strong, subequal, more or less wavy 

incremental striae and by numerous fine, subequal, rather regular 

concentric wrinkles which cover the entire shell. Probably there 

wore a few small spines. No indication of spines was observed on 

the type specimen, but an external mold of the dorsal valve shows 

toward the front a few small, slightly elongated nodes, which represent pits or dimples on the shell itself and doubtless correspond to 

spines on the companion valve. A very few irregularly distributed 

radial plications or costae are also developed on some shells, as on the 

type specimen. The latter also shows traces of very obscure, wavy, 

longitudinal striae, visible only on local areas and probably due to 

exfoliation or to some internal markings showing through. At least 

such an explanation is possible.

This type is evidently very closely related to P. hirsutiformis, and 

in point of the fine; obscure, radiating striae it especially recalls a 

specimen which I figured from the Moorefield shale of Arkansas. 1 

It differs from P. fiirsutiformis in the stronger and more regular 

concentric wrinkles and the less numerous spines.

Horizon and locality. Boone limestone, in beds overlying the. St. 

Joe limestone member, St. Joe, Ark.

i Girty, G. H., U, S. Geol. Survey Bull. 439, PI. Ill, fig. 3,1911.
14 FAUNAS OF THE BOONE LIMESTONE AT ST. JOE, ARK.

PRODUCTELLA MILLESPINOSA n. sp. 

Plate I, figures 5-5c.

Shell small, slightly transverse, with small depressed ears and small 

slightly prominent beak.

The surface is marked by rather fine, regular, concentric wrinkles, 

which extend well toward the front margin, and by great numbers of 

small elongate spine bases. The bases are short over the posterior 

portion of the shell, but gradually become more elongated, with the 

spines more conspicuously located at their anterior end, until they 

pass into irregular discontinuous costse as they approach the anterior 

margin. In the posterior portion of the shell, where the wrinkles 

are developed, the short spine bases stand in concentric rows and the 

evanescence of the wrinkles appears to be correlated with the prolongation of the spine bases. This region of strong wrinkles and small, 

concentrically arranged spine bases is more restricted in some speciinens than in others. In some there are scarcely any very elongated 

bases; in others all the anterior portion is covered with fairly persistent, if irregular, costge. Another variable feature is the shape, 

some specimens being regularly globose with small depressed beak 

and others more narrowly arched with somewhat more prominent 

umbonal region.

The dorsal valve of this type is not known unless it is represented 

by those globose shells with less prominent and smaller beaks which 

I am regarding as mere individual variations.

This rather peculiar species is distinct from any Mississippian type 

known to me. It rather recalls certain Devonian species, such as 

Productella costulata.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark.

PRODUCTUS BURLINGTONENSIS Hall.

-. ." 

The material thus identified comprises four specimens, two dorsal

and two ventral valves. They vary somewhat, one modification 

having slightly coarser costse and slightly stronger and more regular 

wrinkles across -the visceral area. They agree so closely with P. 

'burlingtonensis that I feel little hesitation in referring them to that 

species.

In the synonymy of this species I believe that Prof. Weller's Pfernglenensis should be included. I have specimens from Fern Glen 

which appear to belong to Weller's species and yet which agree very 

closely with specimens of P. burlingtonensis from Burlington. If 

they are true P. fernglenensis the differences by which Prof. Weller 

distinguished that species from P. hurlingtonensis seem to me to be 

neither constant nor very important. If P. fernglenensis is to be
LOWER PAET OP THE BOOFE LIMESTONE. 15

retained as a distinct species, I should either have to record it at 

"Burlington or P. burlingtonensis at Fern Glen, or both.

Horizon and'locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark.

SCHIZOPHORIA SWALLOWI Hall.

Although they are much smaller and although they do not certainly belong to the genus Schizophoria, I would not venture on the 

evidence at hand to distinguish these specimens from 8. swallowi, 

They are three in number, the largest and most perfect being a ventral valve. It is transversely subelliptical in shape and has a length 

of 14 millimeters and a width of 18 millimeters. The cardinal line 

is long (11 millimeters) and the small beak not strongly elevated. 

The surface is marked by the usual fine lira? (twenty-one in 5 millimeters), some of which appear to have been spiniferous.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark.

RlIYNCHOPOllA PINGUIS H. Sp.

Plate I, figures 8-Sc.

The type specimen of this species is finely preserved and has the 

following characters: Shell large, transverse. Outline transversely 

elliptical to subpentagonal. Length 16 millimeters, width 20 millimeters. Convexity rather high. Fold and sinus well developed. 

The fold bends abruptly downward toward the front, so that its junction with the ventral sinus is considerably below the flat-topped 

upper surface. Costse rounded but sharply defined, ten occurring on 

the fold and nine on each side of the dorsal valve.

I have been somewhat in doubt whether this form should not be 

identified with R. leecheri Gregor, in which the variation in the number 

and arrangement of the costas, as given by Gregor, is very great. In 

view, however, of certain differences which undoubtedly exist and of 

the different geologic location, and to some extent of the different 

faunal association, it seems better provisionally to regard this as a 

distinct and therefore a new species. The differences are these: The 

size is 30 per cent larger and the number of plications on the fold is 

greater (Gregor gives.!'our to eight). An additional difference may be 

found in the fact that the costae (in this specimen) are not obsolete 

posteriorly and that the fold of the dorsal valve bends abruptly downward in front, a feature not mentioned by Gregor.

Provisionally I am including here two smaller specimens only 10 

millimeters long, one of which has ten ribs on the fold and nine on the 

lateral areas of the dorsal valve, one rib on either side of the fold being 

somewhat smaller than the rest and not so elevated, being, as it" were, 

situated on the sides of the fold. The other specimen, which is per-
16 FAUNAS OF THE BOONE LIMESTONE AT ST. JOE, ARK.

haps abnormal, is narrow and has eight ribs on the fold and only seven 

lateral ones, the final two or three on either side being represented 

chiefly by denticulations at the margin.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark.

RHYNCHOPORA sp.

A single imperfect specimen appears to represent a species different 

from R. pinguis. The sinus is occupied by six or seven costae, the 

exact number not being determinable, and there are but five lateral 

ribs. The costae, at least the lateral ones, appear to be large and 

chiefly marginal in their development.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark.

SPIEIFER SUBORBICULARIS Hall.

This type is represented in my collection by three specimens having an indicated length of about 40 millimeters and a width slightly 

greater. The shell contracts at the hinge with a more or less circular 

shape. The fold and sinus are simple, the former being well defined 

but not the latter. On each side there are about seven costse which 

occupy about three-fourths of the lateral surface, the parts near the 

hinge being apparently without ribs. The ribs themselves are large 

and somewhat ill defined and obscure. My specimens are exfoliated, 

but they show traces of fine, regular, concentric striae with larger 

striae due to inequalities of growth.

This is pretty clearly the species described by Hall as 8. suborbi&Jr 

laris. Hall did not figure the species, but my specimens closely correspond to his description. They also agree with Meek and Worthen's 

figures, except that they apparently contract a little more strongly 

at the hinge line and that their ribs are a little narrower.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark.

SPIRIFER GRIMESI Hall?

The three specimens included here do not indicate a size even 

approximately equal to that of S. grimesi and hence must be regarded 

as immature. The largest is only 20 millimeters long. Apparently 

the width is considerably greater (about as four to three). The 

cardinal angles are quadrate or slightly obtuse. The most significant 

feature is perhaps the rather strong, narrow, freely bifurcating ribs 

which have a very fine radial sculpture. So far as can be determined 

these specimens have all the characters of the form from the underlying St. Joe limestone which I have referred to S. grimesi.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark.
LOWER PART OF THE BOONE LIMESTONE. 17

SPIBIFER CARINATUS Rowley?

Plate II, figures 1-lb.

This species is peculiar in the prolongation of the fold and sinus 

into an angular projection at the front of the shell. .The single specimen in my collection is small and has a length and breadth about 

equal, 18 millimeters. The cardinal angles are nearly quadrate. 

The area is low. The fold is not well defined, but very rapidly increases in prominence anteriorly. It is subangular rather than 

rounded and seems to be formed by a general rise of the shell from 

either side into a dihedral angle whose edge is its median line. The 

sinus is broad, shallow, and ill defined, making up for the prominence of the fold by projecting hi a sort of nasute extension. The 

ribs are fine, strong, and freely bifurcating and are crossed by fine, 

regular, imbricating, concentric lamellae.

I know of only two species which have this peculiar configuration, 

both described by Prof. Rowley from the lower part of the Burlington 

limestone of Louisiana, Mo. In fact, S. carinatus and S. pikensis 

appear to be so similar that it is difficult to make out any character 

save size in which they markedly differ. S. pikensis is much the 

larger. The only character in which the present form appears to 

differ from S. carinatus is the concentric, imbricating striae, the possession of which is not clearly indicated in Prof. Rowley's description.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark. '

RETICULARIA PSEUDOLINEATA Hall.

It is not difficult to find specimens in the Keokuk limestone a good 

deal larger than Hall's type specimen of R. pseudolineata, but the representatives in the collection from St. Joe are still larger. Aside from 

a very fragmentary example, these are only two in number. The 

smaller has both valves in conjunction but somewhat misplaced. 

The shape is very transverse and regularly elliptical, the dorsal valve 

being 46 millimeters wide and 32 millimeters long. The larger specimen, a dorsal valve, must have been fully 70 millimeters wide and 

48 millimeters long. The shape of this specimen tends rather more 

to the quadrate and is of course not so transverse. All three are covered with strong, rather regular, and rather fine concentric striae, 

while from the bases of the intermediate raised bands proceeded the 

usual small double-barreled spines in concentric rows.

Tjrpical R. pseudolineata does not as a rule have the concentric 

striae so strong and so completely covering the surface as do these 

specimens. Nevertheless, there seems to be almost no doubt that

49776° Bull. 598 15 2
18 FAUNAS OF THE BOONE LIMESTONE AT ST. JOE, ARK.

they should be referred to R. pseudolineata, which, moreover, I have 

in my collection from the Burlington limestone at Burlington.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark.

SPIRIFERINA aff. SPIRIFERINA SUBTEXTA White.

Plate II, figures 2, 2a.

A single ventral valve represents this type in my collection. It is 

10 millimeters long and 14 millimeters wide. The cardinal angles are 

slightly rounded and the outrine curves from each side rapidly to the 

front. The convexity is rather high, but the beak is strongly arched, 

so that the area is only moderately elevated. The sinus is narrow 

and very deep. The ribs which guard it on either side are larger and 

more prominent than the others. There are six of these on each side, 

making fourteen in all, rapidly decreasing laterally in definition and 

in size.

The surface is considerably exfoliated but apparently was traversed 

by fine, strong, regular lamellose concentric ridges.

The shell substance is finely punctate.

The species of Spiriferina which apparently resemble this most 

closely h ave not been authentically figured. I mean S. clarksvillensis, 

S. solidirostris, and S. subtexta. Weller 1 says that S. darJcsvillensis and S. solidirostris lack the punctate shell structure of Spiriferina 

and are therefore probably referable to the genus or subgenus Delthyris. This is certainly an error so far as S. solidirostris is concerned, 

for one of the specimens on the type card shows unmistakably that 

the shell is coarsely punctate. Even the two specimens which 

Weller has selected and described as the typical ones and which 

appear to belong to the same species as the other show punctate 

structure, though in a somewhat less unambiguous manner. An appearance similar to that which they present is sometimes produced 

by granular silicification or by the impression of small grains of sand> 

but such an interpretation would here scarcely be justified.

White, the author of two of the species mentioned, especially 

considered this character in connection with their generic position, 

stating in effect that S. solidirostris had a punctate shell and a median 

septum, that S. subtexta also had a punctate shell and a median 

septum, and that S. clarksvillensis had_an impunctate shell and a 

median septum. According to our present valuation of these characters the first two species would be true Spiriferinas and the last, as 

Prof. Weller says, a Delthyris. Even if it should actually prove that 

among his authentic specimens from Burlington (the Hamburg citation is probably a Delthyris) White had two distinct types, one with 

punctate and one with impunctate shell structure, it seems to me

i St. Louis Acad. Sci. Trans., vol. 16, p. 446,1906.
LOWER PAET OF THE BOONE LIMESTONE. 19

that this subsequent discussion indicates that the name S. solidirostris 

should be restricted to the punctate form. We may fairly suppose 

that he was accurate in his observations and that if he based them on 

specimens which were not typical he would have said so.

Spiriferina or Deltfiyris clarksvillensis being therefore ruled out of 

the comparison, the form from St. Joe more nearly resembles Spiriferina sultexta, for it lacks the median plication on the fold and sinus 

which is a character of S. solidirostris.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark.

ATHYRIS LAMELLOSA L/fiveille".

I have but a single specimen of this type, apparently a young 

individual. It is more transverse than the shell from the St. Joe 

limestone member referred to A. hannilalensis, and hence I am identifying it as A. lamellosa. It also has more well-developed and spreading lamellae than the latter species is known to possess, though there 

may be no real difference in this particular. The width of the dorsal 

valve, exclusive of the lamellae, is 19 millimeters and the height 14 

millimeters. The outline is irregularly elliptical. The widest point 

is a little above the middle, where also the outline is most sharply 

curved. The convexity of both valves is low and neither has a fold 

or sinus developed to an appreciable degree. One of the frill-like 

lamellce, only 8 millimeters from the apex, is partly preserved and is 

nearly 5 millimeters wide; when complete it was probably considerably wider. It is more or less strongly and irregularly fluted.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark.

CLIOTHYRIDINA HIRSUTA Hall?

Here are included four small lenticular shells, the largest of which 

is 11 millimeters long and the smallest only 3 millimeters. The 

largest has the length and breadth about equal and is nearly circular, 

the smallest has the length greater than the breadth and is oval. A 

fold and sinus are not developed.

All show more or less definite traces of the characteristic fimbriae, 

as closely arranged concentric ridges; and the matrix from which one 

specimen was broken clearly shows the spines themselves in an exfoliated condition. In their present form these specimens could hardly 

be distinguished from C. hirsuta, but they may be only young examples of a much larger species such as C. incrassata, and they very 

likely represent the species which occurs in the St. Joe limestone and 

which, to show its relation to the Fern Glen form, I identified as C. 

roissyi Weller non L'fiveille.

Horizon and locality. Boone limestone, in beds, overlying the 

St. Joe limestone member, St. Joe, Ark.
20 FAUNAS OF THE BOONE LIMESTONE AT ST. JOE, ARK.

PELECYPODA.

CYPKICARDINIA RUGOSA n. sp.

Plate II, figures 3-3c.

Shell rather small, transversely elongate, subovate. Width 7 millimeters, height 4^ millimeters. Hinge line nearly straight, about 

two-thirds the entire width. Inferior outline very gently convex, 

rounding inward strongly under the nearly terminal beaks and contracting anteriorly with the hinge. Posterior outline straight and 

truncated above, where it makes an obtuse angle with the hinge line, 

rounding below in a strong, regular curve into union with the inferior 

outline. Convexity rather low, about equal in the two valves. 

Umbonal ridge undefined but strong. Beaks small, nearly terminal, 

conspicuously curved forward as well as downward. A broad, indistinct constriction seems to be developed in the anterior third of the 

shell, which is compressed over the post-umbonal portion.

The surface is marked by regular concentric sulci, separating regular concentric ridges. The discontinuous, sometimes cancellating 

radial striae found in certain species of Cypricardinia have not been 

m.ade out, though they may have been obliterated by exfoliation. 

On the other hand, the concentric ridges give evidence of being 

marked by concentric striae, but these too may be due to exfoliation 

and a chipping away of the shell along the concentric layers of which 

it is composed. The corrugation of the right valve appears to be 

distinctly more subdued than that of the left, the .concentric ridges 

being lower and narrower and the grooves broader and flatter. This 

inequality in the sculpture of the two valves is a feature which I have 

not before noted in Cypricardinia. It may be due in this specimen to 

unequal exfoliation, although I think this explanation is probably 

not the true one. The feature is well shown by the type specimen, 

which retains both valves in conjunction. The only other specimen 

observed is a left valve, and it is strongly rugose, like the left valve of 

the type.

Cypricardinia rugosa appears to be distinguished by its rather 

strongly contracting outline, its prominent umbonal ridge, and its 

highly rugose surface. In the character of the umbonal ridge especially it differs from C.fayettevillensis. From certain Waverly forms 

(such as C. consimilis) it differs in the more contracting shape and in 

the probable absence of radial markings, and from all these species 

possibly in the unequal sculpture of the two valves.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark.
LOWER PART OF THE BOONE LIMESTONE. 21

CARDIOMORPHA ORBICULARIS n. sp.

Plate II, figures 4, 4a, 5, 5a.

This type, from its symmetrical, almost circular shape, might casually be mistaken for a dorsal valve of some Composita or possibly for 

a rotund terebratuloid, if the presence of a little wing on the posterior side of the beak and of regular concentric striae on the surface 

did not give a key to its true relationship. It must, however, find 

place among the Pelecypoda, but its true generic position is somewhat 

in doubt.

The shape of the right valve is subcircular, slightly wider than long, 

about 14 millimeters in one direction and 15 millimeters in the other. 

On the anterior side of the only left valve seen the outline is obscure 

though it seems to round inward to the umbo, but on the posterior 

side a very small triangular wing is developed. The convexity is 

unusually high and the umbones large and strongly incurved. The 

small wing is depressed.

The surface is marked by fine, regular, concentric striae and a few 

irregular varices of growth. The concentric markings become inconspicuous at the sides and the small auricle is crossed by minute 

radial lirse.

The single specimen representing the left valve is somewhat smaller 

than the right, described above, and is distinctly more convex. On 

the anterior side the outline rounds inward so strongly below the beak 

that an emargination is produced. The posterior side, however, is 

prolonged into a broad alation. The convexity is high and the rather 

small beak strongly incurved. The surface shows some pronounced 

irregularities of growth and retains traces of fine, regular, concentric 

striae similar to the sculpture of the other specimen.

The generic position of this form is a matter of doubt. From its 

configuration, which of course is not decisive, one would say that it 

was congeneric with Cardiomorplia subgldbosa of the Waverly group 

of Ohio, and that in turn may well be congeneric with typical Cardiomorpha of Europe. The American shells at present resting within 

the genus, however, almost certainly do not all belong together, and 

probably when completely known they will be found to represent a 

number of groups not at all closely related.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark.

GASTROPODA.

PLATYCERAS EQUILATERA Hall.

A single specimen is included here. It is rather large, measuring 

45 millimeters in extreme length. The apex is closely coiled, gradually enlarged, and turned so that the shell is dextral. The anterior
22 FAUNAS OF THE BOONE LIMESTONE AT ST. JOE, ARK.

portion is very rapidly expanded, gently curved, and more symmetrical. The shell is strongly inclined backward, and the aperture 

has a subtriangular shape, broad on the anterior side and much 

contracted posteriorly.

The peripheral surface is flattened toward the margin and bears 

two indistinct grooves. These correspond to sinuses in the peristome, 

which thus has a somewhat linguiform projection near the middle, 

bounded on each side by a sinus, on either side of which again the 

shell once more projects somewhat. The lateral surfaces are marked 

by strong flexures beyond which the shell is gently convex, contracting to the narrow posterior surface (more abruptly on the upper or 

dextral side), which is abruptly rounded.

The surface was probably marked by fine incremental striae which 

followed the sinuosities of the aperture. At present the thick shell 

is exfoliated, giving it a lamellose surface.

This form appears to be very closely related to if not identical 

with P. eguilatera.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark.

CEPHALOPODA. 

CCELONAUTILUS sp.

This type is represented by a single fragmentary specimen. The 

diameter is about 30 millimeters, and apparently the whorls slowly 

enlarged and embraced part way so as to form a rather wide 

umbilicus. The cross section is subcircular or subquadrate, slightly 

higher than wide, and slightly flattened at the sides and venter; 

impressed on the dorsal area. The sculpture consists of fine revolving lirse which are coarser on the sides Kut grow finer as they pass 

onto the ventral surface, where they become relatively more widely 

spaced and are perhaps wanting altogether mesially. The suture 

(on one of the younger whorls) appears to be straight, but it is incompletely shown.

This is very likely a new species, but it is hardly well enough 

known for description. Its generic position also is rather doubtful.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark.

TRILOBITA.

BRACHYMETOPUS ? ELEGANS n. sp.

Plate II, figures 6, 6a.

This species is known only from a pygidium which is semicircular, 

somewhat wider than long, and which Jias an entire and regularly 

curved outer margin. The width is 13 millimeters and the length
LOWER PABT OF THE BOOFE LIMESTONE. 23

9.5 millimeters. The axis terminates some distance in front of the 

margin, is abruptly rounded off at the posterior extremity, and 

expands rather rapidly forward. It is subangular rather than curved 

in cross section, or, more exactly, it is made up of four surfaces 

which form a median ridge and two lateral ridges. It is well defined 

by lateral furrows. The lateral lobes are oblique, moderately convex near the axis, but recurved toward the margin, so that they 

have a sigmoidal shape in cross section. Both the convex and the 

concave flexures die down posteriorly and the narrow strip which 

passes around the end of the axis is almost flat, though directed 

obliquely downward. The segments, of which there are nine on the 

sides and fourteen on the axis, are defined by rather deep broad 

grooves. As would be inferred from the difference in number of 

segments, the segmentation of the axis is discrepant with that of the 

sides, and neither the segments nor the grooves which divide them 

are continuous from one to the other, though this is less obvious at 

the front of the pygidium than posteriorly. On either side of the 

axis near the axial furrows the grooves abruptly expand and deepen, 

so that they resemble little pits, thus allowing the axial segments 

to become expanded at their termination. A row of pointed nodes 

is developed along the middle of the axis and a row of smaller ones 

a little less than halfway down the sides. This gives the axis its 

four-sided shape in cross section. The pleural segments are double, 

the anterior moiety in each case being larger and more prominent 

than the posterior. Furthermore, the smaller or posterior portion 

terminates at what may be called the border or upturned rim of 

the pygidium, but the larger extends to its very margin, being, if 

anything, stronger on the border and more angular. The larger 

segments also bear nodes, two apiece, which form two rows on each 

of the pleural surfaces. The nodes are of unequal size, the smaller 

ones occurring next the axis. This row is not persistent and appears 

to be absent from the last two segments, on -which, however, the 

larger nodes are developed in especial strength. The final segments 

of the lateral lobes are parallel and directed straight backward from 

the sides of the axis, the space between them being slightly raised.

This species is unique, so that a comparison with other American 

types is unnecessary. It seems most to resemble certain species 

of Brachymetopus, and on that account it has been provisionally 

placed in that genus, but an accurate determination of the generic 

relationship is not possible from the pygidium alone.

Horizon and locality. Boone limestone, in beds overlying the St. 

Joe limestone member, St. Joe, Ark.
24 FAUNAS OF THE BOONE LIMESTONE AT ST. JOE, ARK. 

THE ST. JOE LIMESTONE MEMBER. 

INTBODUCTION.

During the summer of 1904, at Louisiana, Mo., I had the privilege of examining the interesting collection of Carboniferous fossils 

owned by Prof. R. R. Rowley. Some specimens from a reddish 

shaly rock especially drew my attention by their excellent preservation, the unusual character of some of the species, and the fact that 

they resembled, in some respects very strikingly, a fauna from the 

far-distant Lake Valley limestone of New Mexico. Upon inquiry 

it proved that these fossils were obtained at Fern Glen, west of St. 

Louis, in the limestone subsequently called by Prof. Weller the Fern 

Glen formation. Somewhat later in the same year I was able to 

visit Fern Glen and to obtain a suite of specimens of my own.

It was my purpose at that time to prepare a report describing the 

combined fauna of the Fern Glen and Lake Valley limestones, and I 

assembled considerable material to that end, but other more pressing 

matters intervened and the project was deferred from year to year. 

So, when Prof. Weller's paper on "The fauna of the Fern Glen 

formation" appeared,in 1909,1 my work was still in an inchoate state.

In the report just mentioned Prof. Weller pointed out the relations of the Fern Glen and Lake Valley faunas, but was unable to 

include the latter in his discussion, except so far as it had been 

described by S. A. Miller. 2 Prof. Weller furthermore correlated the 

Fern Glen fauna with that of the Chouteau limestone, a relationship 

to which my own studies had pointed, and also with the fauna of the 

St. Joe limestone member of the Boone limestone of northern Arkansas, with which I was then unacquainted. At the time when Prof. 

Weller wrote only 29 species were known from the St. Joe limestone 

and only 2 (Zaphrentis sp., crinoidal columns, and Spirifer grimesi) 

from the typical locality at St. Joe. Furthermore, the 29 species 

were merely listed with perhaps rather hasty identifications and with 

the possibility of the same type appearing under different names.

The Survey collections from St. Joe comprise 40 species,3 considerably more than were previously known from the entire St. Joe 

limestone and greatly more than were previously known from the 

same locality. By briefly describing this fauna in the form of an 

annotated list, it seemed that I might make a small addition to 

geologic data and at the same time return to the study of a fauna in 

which at one time I felt considerable interest.

1 Geol. Soc. America Bull., vol. 20, pp. 265-332,1909.

2 Cincinnati Soc. Nat. Hist. Jour., vol. 4, p. 306 et seq., 1881.

3 In addition to the 40 invertebrate species it is important to record the presence of a Dynichthyid tooth 

which may provisionally be identified as Dynichthys gouldi. This identification I owe to the courtesy of 

Dr. Bashford Dean and of Prof. C. R. Eastman, both of whom examined it.
THE ST. JOE LIMESTONE MEMBEK. 25

Iii the present classification of the United States Geological Survey, 

the St. Joe limestone is regarded as a member of the Boone limestone. 

The name appears to have been introduced in 1893 by Hopkins,1 

who, however, did not designate a type section nor describe the 

formation bed by bed. It is clear, however, that the typical locality 

is St. Joe, Ark., and it is not unlikely that the typical locality is that 

from which most of my collections were obtained beside the railroad 

along Mill Creek, a short distance northwest of St. Joe. Hopkins 

describes the St. Joe as consisting of from 25 to 40 feet of limestone 

without chert, varying in color from light pink to dark chocolate, 

interspersed with spots of white, gray, or pea green. It comprises 

the basal beds of the Boone and has been recognized over the greater 

part of northern Arkansas. According to Hopkins the St. Joe is 

entirely lacking in some sections, the chert of the higher Boone 

resting directly upon the Silurian rocks. Unless the St. Joe has 

changed out of all recognition lithologically, this fact would suggest 

an unconformity between the St. Joe and the rest of the Boone. The 

paleontologic features of the St. Joe have been described by H. S. 

Williams. 2

It has seemed best to restrict the scope of the present paper to the 

material obtained at the typical locality, at or near St. Joe. This 

material consists principally of two collections, one made by E. 0. 

Ulrich and the other made subsequently by myself.. A third collection was made by Prof. Weller in 1891, while he was connected with 

the United States Geological Survey, and this is the one mentioned 

above, which was listed by Prof. Williams 2 and included by Prof. 

Weller himself in the list of St. Joe fossils in his Fern Glen paper.3

My own collection was obtained from an exposure along the railroad 

about 1£ miles northwest of the station at St. Joe. The rock here 

consists of red crinoidal limestone in thin beds with partings of red 

shale, the original color of which appeared to be greenish. Hand 

specimens of the St. Joe limestone show that the color ranges from 

light gray or greenish to a dark dull red, and the texture from very 

fine to coarse. The texture, and to some extent the color, appears 

to depend directly on the amount of crinoidal material present. 

Seemingly the rock is made up of two elements, a fine calcareous 

mud and crinoidal segments (and some plates) in quantity, some 

layers being practically composed of this material. The fine mud or 

paste seems to range in color from greenish or gray to red, the red 

mud being partly calcareous but less so than that which is greenish. 

The greenish and pinkish colors seem generally to be associated with

1 Hopkins, T. C., Arkansas Geol. Survey Ann. Kept, for 1890, vol. 4, pp. 253, 290,1893.

2 Arkansas Geol. Survey Ann. Kept, for 1892, vol. 5, p. 331,1900. 

« Geol. Soc. America Bull., vol. 20, pp. 265-332,1909.
26 FAUNAS OF THE BOONE LIMESTONE AT ST. JOE, ABK.

the crinoidal bands; possibly the intensely red sediments do not 

occur in the crinoidal layers at all. They do occur with other fossils, 

however, adhering so closely to many of them as to obscure their 

superficial characters. Though the strata appear to have been but 

little disturbed, some of the fossils are compressed and folded together, 

more or less slickensiding of the red paste accompanying the movement. A few fossils are faulted, narrow veins of calcite occupying 

the fracture.

Below the St. Joe limestone 1 foot to 4 feet of very variable beds 

were found, mostly greenish, grayish, or black shale with some harder 

rock, the top layer being usually a hard, fine, semicalcareous ledge 

about 6 inches thick containing black phosphatic (?) nodules. The 

rocks overlying the St. Joe belong to the Boone limestone with a 

rather well defined division between the two, the St. Joe being red 

and containing no chert or but very little, whereas the overlying part 

of the Boone is a white rock varying from coarse and crinoidal to 

fine and hard in texture and bedded with white chert, which at higher 

horizons becomes predominant. The thickness of the St. Joe at this 

point was estimated to be 30 feet and most of the fossils were found 

near its base. As Mr. Ulrich's collection is supposed to have been 

made at the same place and horizon as my own, the two will not be 

distinguished in this paper.

Prof. Weller also, it would appear, visited this locality in 1891. His 

notes describe the rock as a red marble and give its thickness as 30 

feet. Above, there was said to occur 5 feet of coarse,'gray, crystalline 

crinoidal limestone overlain by intermingled chert and limestone, and 

below there occurred 4 inches of white or blue sandstone containing 

numerous hard black pebbles. Prof. Weller obtained no fossils here, 

the place where his small collection was made being described as 1 

mile southeast of station 1238B, which is given as Tomahawk Creek, 

5 miles east of St. Joe. This collection was obtained in the upper 

instead of the lower part of the St. Joe, and for this reason separate 

mention seems desirable in spite of the small number of species present. As I have identified them these include, besides crinoid fragments, Amplexus' rugosusf, Zaphrentis aff. ZapJirentis dalei, and 

Spirifer grimesi. The Spirifer and probably the Zaphrentis have 

been found in the larger collections made by Mr. Ulrich and myself, 

and Amplemis rugosus?, a species described from the Fern Glen limestone, points to the same faunal association.

Thus the fauna of the St. Joe limestone from St. Joe comprises as 

now known 40 species, of which 3, or in reality only 2, were known 

there before. Most of the species are already in the literature. Two 

of them are undescribed, and possibly more would prove to be so if
THE ST. JOE LIMESTONE, MEMBER. 27

definite conclusions were not prevented by the rather imperfect preservation in which most of the fossils were found.

A comparison of this fauna from St. Joe with faunas from other 

points in the St. Joe limestone may well await another occasion and 

larger collections.

As already noted, Prof. Weller correlates the St. Joe and Fern Glen 

limestones, and the paleontologic evidence which he advances is 

considerably increased by the data which I have been able to record. 

He distinguished 66 species in the Fern Glen fauna, 15 of which were 

common to the St. Joe limestone. Or, from the other point of view, 

of the 29 species before recorded from the St. Joe over half were found 

in the Fern Glen limestone. Of the species distinguished in the 

present paper 12 probably or certainly occur also in the Fern Glen 

fauna, and if to these be added, on Prof. Weller's authority, 8 St. Joe 

species not yet obtained at the typical locality, which likewise OCCUI in 

the Fern Glen fauna, 20 out of the 66 Fern Glen species are at present 

known in the St. Joe limestone. The strength of this evidence becomes a little clearer if it is remembered that 16 of the 66 Fern 

Glen species are crinoidal types and that though crinoidal remains 

play a very important part in the composition of the St. Joe limestone no determinable crinoids have yet been found in it. It should 

be noted again here that this evidence, strictly interpreted, correlates 

only the lower portion of the St. Joe limestone with the Fern Glen 

limestone. On the other hand, the St. Joe seems to be uniform in 

lithologic character, x and the very small fauna which I have mentioned from the upper part points more or less uncertainly to the 

same correlation as that from the lower beds.

As already remarked, Prof. Weller correlates the Fern Glen limestone and therefore the St. Joe limestone with the Chouteau limestone; 

and with this correlation I am quite in accord. I may, however, 

differ with him in his correlation of the Chouteau limestone itself. 

In brief, he places the Chouteau limestone in the Kinderhook and 

therefore below the Burlington, whereas I am disposed to think that 

it may correlate with the lower part of the Burlington.

I have had this possibility in mind for a number of years but have 

not found time to arrange for presentation or to entirely verify the 

evidence which seems to support it. For this reason, and because I 

hope to return to the subject, I will only indicate at this place the 

general character of this evidence.

I believe that the proper boundary between the Kinderhook and 

the Burlington is at the base of the upper or principal oolite in the 

Burlington section, this strictly calcareous bed being thus thrown with 

the limestone series above rather than with the mainly sandstone
28 FAUNAS OF THE BOONE LIMESTONE AT ST. JOE, ARK.

series below. If the Burlington is thus denned, the lower Burlington 

fauna will, I believe, be rather sharply distinguished from the Kinderhook.

Though crinoid specialists have long distinguished an upper Burlington and a lower Burlington fauna, adequate recognition of the 

dual nature of the Burlington appears to have been by no means 

general. The Burlington fauna described by Hall is essentially the 

upper Burlington fauna, and most references to the Burlington pertain, I believe, to this rather than to the lower facies. Not only so, 

but at Sedalia, Chouteau Springs, and other localities in Missouri, 

which may be called typical for the Chouteau limestone, it appears, 

from the fauna, to be not the lower part of the Burlington but the 

upper part which follows that formation in the geologic series. The 

fauna of the lower part of the Burlington is not only considerably 

different from the fauna of the upper part, but it strikingly resembles 

the fauna of the Chouteau limestone.

These statements, as already noted, need verification and are not 

made unqualifiedly. It seems worth while, however, to cast this 

suggestion into the arena of discussion, even in advance of a more 

complete and careful presentation, rather than to allow the correlation 

of the St. Joe with the Chouteau limestone and its classification as 

Kinderhook to go unquestioned.

If the Chouteau limestone does correlate with the lower Burlington, 

it will be necessary to redefine the Kinderhook group so as to exclude 

the Chouteau limestone and its correlates, and also to reclassify the 

section at Burlington itself so as to include with the Burlington lime^ 

stone the upper oolite, commonly placed in the Kinderhook. This 

would diminish considerably the distribution of the Kinderhook rocks, 

but give greater uniformity to the Kinderhook fauna.

CCELENTERATA.

ZAPHRENTIS aff. ZAPHRENTIS DALEI Milne-Edwards and Haime.

This form suggests Z. dalei chiefly by its large size, one specimen 

measuring no less than 5 centimeters across the calyce. The specimen 

is a mere fragment, but the dimension given, though estimated, is 

probably not far from accurate. Another specimen provisionally 

assigned to the same species has a diameter of 2.5 centimeters, which 

is in close agreement with the typical size. In the smaller specimen, 

which is also a fragment, the surface is nearly smooth; in the larger 

the septa produce slender ribs on the exterior, the crests of which are 

a little less than 2 millimeters apart. The larger has also fine concentric striae.

Horizon and locality. St. Joe limestone member of the Boone limestone, St. Joe, Ark.
THE ST. JOE LIMESTONE MEMBEE. 29

ZAPHRENTIS sp.

Here are included a group of specimens characterized by being 

rather small, rather curved, rather rapidly expanded, and rather 

deeply calyced. It is hardly possible to give more exact data or to 

identify the form from the scanty and imperfect material at hand. I 

am not even certain that all the specimens are congeneric. An average example would be about 25 millimeters long and 15 millimeters 

in diameter.

In general appearance this form resembles Prof. Weller's Amplexus 

brews, but has a deeper calyce. It is doubtful whether either species 

belongs in the genus Amplexus.

Horizon and locality. St. Joe limestone member of the Boone limestone, St. Joe, Ark.

AMPLEXUS RUGOSUS Weller?

I am including here a single fragmentary specimen whose shape is 

generally cylindrical, though it is much contorted and constricted. 

The external surface is marked by fine concentric strise, by coarser 

annulations, and by irregular constrictions. The diameter is about 

13 millimeters. The septa number twenty-one. They leave a space 

in the middle equivalent to one-third of a diameter or less, occupied 

only by tabulae.

This species resembles A. rugosus, but is somewhat larger and has a 

larger central area not traversed by the septa. In this it has more 

the character of typical Amplexus, to which I would judge A. rugosus 

somewhat doubtfully belongs.

Horizon and locality. St. Joe limestone member of the Boone limestone, St. Joe, Ark.

CYATHAXONIA AECUATA Weller?

In this group are placed a few poor specimens, one of which shows 

the Cyathaxonia structure. They are distinguished from the form 

called C. minor? by being larger and more arcuate. None of them 

is produced to the length of the type specimen (of 0. arcuata) figured 

by Prof. Weller.

Horizon and locality. St. Joe limestone member of the Boone limestone, St. Joe, Ark.

CYATHAXONIA MINOR Weller?

The specimens under consideration are so imperfect and so few that 

a sure identification is not possible. One of them at least is congeneric with Cyathaxonia minor, and all suggest it specifically in such 

characters as can be made out.

Horizon and locality. St. Joe limestone member of the Boone limestone, St. Joe, Ark.
30 FAUNAS OP THE BOONE LIMESTONE AT ST. JOE, ARK.

CLADOCHONUS AMERICANUS Weller?

This form is represented by a few fragmentary corallites only. 

They are not attached to any other body, and on this account their 

generic position is probably with Cladochonus rather than with 

Aulopora or Monilipora. In their imperfect condition the corallites 

have neither the length nor the radial dimensions of 0. americanus 

(they measure 3 millimeters in diameter and 6 millimeters in length), 

but the indications are that both dimensions were appreciably greater 

in the complete specimen. The mode of growth in this particular 

colony, however, is apparently not quite so linear as that of the particular colony taken as the type.

Horizon and locality. St. Joe limestone member of the Boone limestone, St. Joe, Ark.

ECHINODEBMATA.

CRINOIDAL REMAINS.

Crinoidal remains are common in the St. Joe limestone. In fact 

some layers consist of little else. They comprise circular stem segments, many of which are rather large, though few exceed 15 millimeters in diameter. A few specimens of what are possibly basal 

plates of some species of Platycrinus have been observed.

Horizon and locality. St. Joe limestone member of the Boone limestone, St. Joe, Ark.

BBYOZOA.

FlSTULIPORA RUBRA n. sp.

Plate III, figures 1-5.

Zoarium consisting of thin expansions, which are highly contorted 

and often superposed. The layers are sometimes only 2 millimeters 

thick, but they may attain a thickness of 5 millimeters or more at 

certain points or over small areas. The sheets are contorted or are 

folded over or even elevated into nodes. By the superposition of 

consecutive layers, which may or may not be in contact, the zoarium 

attains a thickness of 20 millimeters or perhaps considerably more. 

The largest example seen is about 50 millimeters across.

Monticules, apart from prominences due to contortions of the 

zoarium, are absent. So also are maculae of the usual character 

that is, depressed granular areas which are noncelluliferous. There 

appear, however, to be areas of closely arranged and areas of more 

widely separated apertures, though probably these are conditioned 

by the irregular growth of the zoarium and have no constant relation 

to one another. The zocecia are subcircular in section, though they 

possess a strongly marked lunarium, which occupies about a third of
THE ST.. JOE LIMESTONE MEMBEB. 31

one side, and as a'rule they appear to be more or less regularly 

arranged in quincunx. Some of the zooecia are elongated, and the 

lunarium is on either the long or the narrow side. In some areas 

they are about 0.2 millimeter across and are separated by intervals of one and one-half to two times their own diameter. In places, 

however, they are larger and more closely arranged 0.3 millimeter 

in diameter, separated by one-half their own diameter or less. Perhaps their average size is 0.25 millimeter, and their average spacing 

is one to one and' one-half diameters. The mesopores occur in one, 

or more often two, rows between adjacent zooecia, and where the 

latter are small some of the mesopores are fully as large as the 

zooecia. Diaphragms appear to be irregularly developed. They are 

curved and very delicate and are irregularly arranged. They have 

been observed at less than a diameter, at one and one-half diameters, 

and at two diameters apart. In some zooBcia they seem to be absent 

altogether.

This species differs from F. fernglenensis in its mode of growth, 

which is much more irregular and which produces zoaria made up 

of numerous superposed layers. The zooecia are also much smaller. 

According to Prof. Weller, about two zooecia and two interspaces 

occur in 2 millimeters, while in this type about four zooecia and three 

interspaces occupy the same distance.

Horizon and locality. St. Joe limestone member of the Boone 

limestone, St. Joe, Ark.

CYSTODICTYA LINEATA Ulrich.

Two rather poor specimens appear to belong to the Fern Glen 

species that Prof. Weller identified as Gystodictya lineata. They 

agree with his description in all the characters which can now be 

determined.

Horizon and locality. St. Joe limestone member of the Boone 

limestone, St. Joe, Ark.

CYSTODICTYA LINEATA var. MAJOR Ulrich ?

Several rather poorly preserved specimens have been referred to 

this species. One of them is large and shows the manner of growth 

well but the more minute characters only indifferently. The stipes 

are 6 to 7 millimeters across and 1 millimeter or somewhat less in 

thickness. They are profusely branched, not only in the plane of 

the stipe but at an angle to the plane as well. The complanate 

branches occur in alternation on opposite sides of the main stipe, 

which has thus a sinuous course, branches on the same side being situated about 15 millimeters apart. The width is considerably increased 

in the proximity of branches that lie in the plane of the stipe, and
32 FAUNAS OF THE BOONE LIMESTONE AT ST. JOE, ARK.

the thickness in the proximity of branches that lie oblique to that 

plane.

The specimen from which the foregoing data are derived is embedded in limestone, and, in breaking, the fracture has for the most 

part passed along the median plate. The apertures, where seen, are 

small, triangular or trefoil shaped, and are spaced about twice their 

own diameter apart. They occur in numerous rows, with apparently 

no longitudinal grooves or other surface markings.

The scarcity of material, together with its poor'preservation, has 

prevented the determination of some important measurements, and 

some of the statements made above are subject to revision.

In a general way this form suggests Gystodictyalineata var. major, 

but more perfect specimens will probably show it to be new.

Horizon and locality. St. Joe limestone member of the Boone 

limestone, St. Joe, Ark.

EUACTINOPORA QUINQUERADIATA Ulrich.

This species is rather common in the St. Joe limestone. Different 

specimens show different numbers of rays or arms, though five is the 

usual equipment. Thus seven have .five arms, three have four arms, 

and one has six arms. The rays are of the long, slender type, as in 

guingueradiata, whether the number be four or five or six.

Horizon and locality. St. Joe limestone member of the Boone 

limestone, St. Joe, Ark.

CHEILOTRYPA? sp.

This type is. represented by a fragment of a cylindrical stem 7 

millimeters long and slightly over 1 millimeter in diameter. The 

apertures are situated at relatively wide intervals. Their arrangement is not certainly determinable from the specimen, but they 

appear to be developed in longitudinal rows without any constant lateral relationship. The intervals are about two diameters longitudinally 

and one diameter or more laterally, but this is not clearly shown. 

The surface surrounding the apertures is marked by irregular, discontinuous, longitudinal strise.

Horizon and locality. St. Joe limestone member of the Boone 

limestone, St. Joe, Ark.

FENESTELLA HERRICKANA Ulrich?

Two specimens which stand very close to F. Tierrickana in their 

specific relationship and perhaps are identical with it are included 

under this caption.

Horizon and locality. St. Joe limestone member of the Boone 

limestone, St. Joe, Ark.
TH-E ST. JOE LIMESTONE MEMBER. 33

FENESTELLA sp. a.

A large but very poorly preserved frond which has much the 

structure and proportion of Polypora sp. but which is nevertheless 

apparently a true Fenestella.

Horizon and locality. St. Joe limestone member of the Boone 

( i limestone, St. Joe, Ark.

FENESTELLA sp. 6. and c.

^ The Fenestellas in my collection from the St. Joe limestone are 

rather few in number, fragmentary, and more or less eroded or 

weathered. Besides the types distinguished above are two others,

. clearly distinct from those as from each other, but so poorly preserved as not to justify the effort to identify them.

Horizon and locality. St. Joe limestone member of the Boone

. limestone, St. Joe, Ark.

1 " POLYPORA sp.

This type is represented by a single fragment showing only one 

side. The construction is on a small scale, nine branches occurring 

transversely and six fenestrules longitudinally in a distance of 5 

millimeters. The fenestrules are elliptical, about twice as long as 

wide. The apertures occur in two rows, increased to three a short 

distance below the bifurcation of a branch. P. biseriata is a related 

form.

">ru Horizon and. locality. St. Joe limestone member of the Boone 

limestone, St. Joe, Ark.

BBACHIOPODA.

LEPTJSNA ANALOG A Phillips.

This type is represented by .a single specimen, which in spite of its 

very fragmentary condition can hardly be assigned to any other 

species than L. analoga.

; Horizon and locality. St. Joe limestone member of the Boone 

I limestone, St. Joe, Ark. 

^ i}

j CHONETES ILLINOISENSIS Worthen.

A single specimen in a poor state of preservation, whose probable 

reference is determined by its very fine liration.

 { Horizon and locality. St. Joe limestone member of the Boone 

limestone, St. Joe, Ark. : 

49776° Bull. 598 15 3
34 FAUNAS OF THE BOONE LIMESTONE AT ST. JOE, ARK.

PRODUCTELLA CONCENTRICA Hall.

This characteristic Chouteau form was not found by Prof. Weller 

in the Fern Glen fauna nor has it before been recorded from the 

St. Joe limestone. It is, however, rather abundant in the St. Joe 

limestone at St. Joe and presents a typical development of the 

species.

Horizon and locality. Si. Joe limestone member of the Boone 

limestone, St. Joe, Ark.

PRODUCTELLA PYXIDATA Hall?

This is a species of moderate size and convexity, of which the surface is marked by fine concentric striae, fine irregular concentric v 

wrinkles, and numerous small, rather obscure tubercles of rounded 

shape, from which small spines doubtless proceeded.

P. pyxidata, which this form most closely resembles, is found, when 

a large series of specimens is examined, to present several modifica- i' 

.tions. One type is nearly smooth; another is marked by fine concentric -wrinkles; another has in addition small spine bases; and still 

another has the spine bases more or less extended into somewhat 

irregular intermittent costas.

The specimens from St. Joe are only four in number, one large and 

three small, and none of them is in very satisfactory condition. They 

do not, of course, exhibit the complete range of variation shown by 

P. pyxidata, but they closely resemble the second and third mutations 

mentioned above, and it would be difficult to name satisfactory characters for their discrimination. "'

Horizon and locality. St. Joe limestone member of the Boone 

limestone, St. Joe, Ark.

PRODUCTUS LEVICOSTA White.

This species is represented by a diminutive and probably very 

young specimen, but the identification is believed to be fairly safe. *

Horizon and locality. St. Joe limestone member of the Boone 

limestone, St. Joe, Ark. ^

PRODUCTUS SAMPSONI Weller.

\

This species is a small representative of the cora group. It was 

recognized by Prof. Weller in the Fern Glen fauna but was described 

by him from specimens found in the Chouteau limestone. In my 

St. Joe collections it is represented by two specimens of whose specific 

identity there can be little doubt. The species is also common in the 

Cuyahoga shale of the Waverly group of Ohio. "

Horizon and locality. St. Joe limestone member of the Boone , ' 

limestone, St. Joe, Ark.
THE ST. JOE LIMESTO.NE MEMBER. 35

RHIPEDOMELLA BUBLINGTONENSIS Hall.

This is doubtless the species called RMpidomella michelinia by Prof. 

Weller, the correct spelling of the name being RJiipidomella micJielini. 

Prof. Weller does not state that the observations which found no 

difference between European specimens of R. micTielini and R. micfielini var. burlingtonensis were made by himself, nor that the European 

specimens were authentically identified, so that I am provisionally 

employing the American name, which may, however, be superseded 

in the manner indicated by Prof. Weller.

The St. Joe specimens suggest that the species is not uncommon, 

but they are so imperfect that I have been unable to satisfy myself 

that some do not belong to Schizophoria, perhaps toSchizophoria swallowi. The largest is somewhat over 25 millimeters long.

Horizon and locality. St. Joe limestone member of the Boone 

limestone, St. Joe, Ark.

CAMAROPHORIA SIMULANS n. sp. 

Plate II, figures IG-lOc, 11-llb.

Shell rather large, subovate to subpentagonal. Length and 

breadth about equal, the latter possibly a little in excess. Ventral 

valve moderately convex; dorsal valve inflated. The two valves are 

plicated medially into a strong fold and sinus, which is either narrow 

and rounded or broad and more quadrate. The ventral beak is small 

and strongly incurved.

The surface is possibly devoid of costse. None of my specimens 

show any lateral ribs. In one the fold also appears to be unplicated. 

In another, however, the sinus shows traces of very obscure ribs, about 

four in number, which may possibly be due- to internal markings, 

though I think not.

This species is externally very unlike any of the Mississippian types 

of Camarophoria. On the other hand, it closely simulates Shumardiella missouriensis of Shumard (typical). S. missouriensis, however, 

is a true rhynchonellid, whereas the present form certainly has the 

dental plates united internally into a spondylium and hence is a true 

pentameroid.

Horizon and locality. St. Joe limestone member of the Boone limestone, St. Joe, Ark.

CAMAROTGECHIA METALLICA White?

I am here including two specimens only a larger, 8 millinieters 

long, and a smaller, 6 millinieters long. Both appear to be mature or 

nearly mature. The smaller, which is the more perfect, has five 

plications on the fold and five lateral ones; the other appears to have
36 FAUNAS OF THE BOONE LIMESTONE AT ST. JOE, ARK.

more numerous mesial ribs, perhaps six. The ribs are strong and 

angular and the fold and sinus are well developed, especially in the 

larger example.

The relationship which these specimens bear to Oamarotcechia 

cooperensis is perhaps debatable, but they appear to represent a 

distinct species by reason of their smaller size and more angular ribs. 

These characters and the arrangement of the costae indicate a form 

closely resembling C. metallica.

Horizon and locality. St. Joe limestone member of the Boone 

limestone, St. Joe, Ark.

CAMAROTCECHIA aff. CAMAROTCECHIA COOPERENSIS Swallow.

Included here are a few very small specimens which somewhat 

suggest the form identified as C. metallica f, but they differ in having the plications much less angular as well as differently arranged. 

One specimen 6 millimeters in length, which is about the average 

size, has six plications on the fold and five or six lateral ones. 

The low convexity and partly developed fold and sinus indicate 

that they are young specimens, and their general aspect suggests that 

they are the young of some species of the cooperensis type. The shell 

structure does not appear to be punctate.

Horizon and locality. St. Joe limestone member of the Boone 

limestone, St. Joe, Ark.

CAMAROTCECHIA n. sp. ?

This type is represented by a single specimen which has an elongated 

subtriangular shape suggestive of Rhynchotetra caput-testudinis, but 

the presence of two dental plates in the ventral valve makes clear that 

it belongs to a different genus, while the presence of a median septum 

in the dorsal valve indicates that the genus is prob ably Camarotoechia. 

This is a small and probably a young shell, having a length of 7 millimeters and a greatest width of 6 millimeters, the latter measurement 

lying close to the front. The fold and sinus are rather poorly developed. The plications are relatively large and rounded and can be 

traced to the beak on both valves. Four of them occupy the fold 

and four occur on each of the lateral areas of the dorsal valve. The 

surface is also marked by rather fine, regular, indistinct concentric 

striae. '

This is probably a new species, but the fact that I have only a single 

specimen, which, moreover, appears to be immature, makes it inadvisable to introduce a new name at this juncture.

Horizon and locality. St. Joe limestone member of the Boone 

limestone, St. Joe, Ark.

'
THE ST. JOE LIMESTONE MEMBER. £7

RHYNCHOPORA sp.

It is sometimes very difficult to detect the critical shell structure 

of Rhynchopora. Most specimens which come up for examination 

are more or less exfoliated, and in some it is possible to find a showing 

of punctate structure only about the margin. Thus, however much 

one may be on guard, the possibility of confusing this type with the 

structurally similar Camarotcechia is always imminent.

Two large shells having much the external appearance of Camarotcechia cooperensis exemplify these statements in the St. Joe collection. 

They exhibit unmistakably the punctate structure, though only in a 

few small areas, and hence they belong to the genus Rhynchopora.

One retains both valves and the other only the dorsal valve, and 

neither is in very good preservation. The shape is highly gibbous

and transverse, the plications coarse and rounded. Of these five 

occur on the strongly elevated fold and five, perhaps six, on each 

of the sides.

Only two species of Rhynchopora are at present known from the 

Mississippian, R. beecheri and R. pustulosa. So great a range of 

variation is shown by the specimens which Gregor includes under 

R. heecheri that apparently my shells might be regarded as belonging 

to that species. Gregor's figures, however, show a smaller form, 

with much finer, more angular, and more numerous plications. It is 

clear that my specimens can not be regarded as typical R. beecheri, 

even if included in that species at all. They perhaps resemble 

R. pustulosa a little more nearly, but are larger, more gibbous, and 

more numerously plicated.

Horizon and locality. St. Joe limestone member of the Boone 

limestone, St. Joe, Ark.

SHUMARDIELLA MISSOURIENSIS var.

Shumard! figured two specimens, of what he described as a single 

species, Rliynchonella missouriensis. The smaller he regarded as a 

young example of the larger. As is well known, the larger shell 

differs from the smaller not only in size and in the strength of the 

plications, but also in being covered by fine, radiating lirse, and 

Meek and Worthen introduced for it the specific name striaticostata, 

restricting the term missouriensis to the smaller species. At the 

same time typical missouriensis does appear to undergo modifications which cause it to approach at least striaticostata 1 in the character 

of external form.

1 Prof. Weller has introduced the names Paraphorhynchus and Shumardiella for the generic types represented, respectively, by P. striaticostatum and 8. missouriensis.
38 FAUNAS OF THE BOONE LIMESTONE AT ST. JOE, ARK.

A very fragmentary specimen from the St. Joe limestone looks as 

if it might be part of a typical specimen of striaticostata, except that 

it shows no traces of radiating lirse. It probably belongs to one of 

the modifications of 8. missouriensis or to a variety closely related 

to them.

Horizon and locality. St. Joe limestone member of the Boone 

limestone, St. Joe, Ark.

DIELASMA? sp.

This type is represented by a single small specimen which nevertheless appears to be mature. The length is 12 millimeters and the 

shape ovate. This is clearly not the very large species which Prof. 

Weller described as Dielasmafernglenensis, but its specific relations 

are not determinable from the data at hand.

Horizon and locality. St. Joe limestone member of the Boone 

limestone, St. Joe, Ark.

SPIRIFER GRIMESI Hall.

This species is represented by three determinable specimens, besides 

several others so imperfect and poorly preserved that their specific 

relations are a matter of uncertainty. Aside from its shape and 

costation this species is distinguished by having the ribs overlain by 

very fine, regular, radiating lirae, not to be discerned without a lens. 

Concentric markings there are, too, in the shape of very delicate, 

sublamellose growth lines, but these are more closely arranged and 

delicate than the radiating lirse, and in fact are rarely preserved, so that 

most specimens appear to possess the radiating striae only.

Horizon and locality. St. Joe limestone member of the Boone

limestone, St. Joe, Ark.

SPIRIFER PECULIARIS Shumard.

i

The original of this, identification is a small Spirifer having a subpentagonal or subrhombic shape, highly convex valves, and rounded 

cardinal angles. The fold and sinus are moderately elevated and are 

wider than the lateral plications, which are broad and not strongly 

defined. About five occur on either side of the fold, which seems to 

have toward the front a faint median sulcus, but which is otherwise 

unplicated. The surface, though exfoliated, shows traces of rather 

fine, regular, concentric striae.

I have been somewhat doubtful where to place this rather well 

preserved specimen, the species chiefly involved in the question 

being S.fernglenensis, S. chouteauensis, and S. peculiaris. A specimen 

from Fern Glen, which seems to be a representative example of S. 

fernglenensis, presents a very different appearance, having a more
THE ST. JOE LIMESTONE MEMBER. . 39

transverse shape and coarser, more strongly defined lateral costse. I 

have also compared this shell with several specimens from the Chouteau limestone which I do not hesitate to identify as Spirifer peculiaris, and it seems to me that it may very well be a young example of 

that species. But the Chouteau specimens are very suggestive of the 

form which Prof. Weller has described from the same formation as 

Spirifer chouteauensis and which he says has often been mistaken for 

S. peculiaris. The differentiating characters mentioned by the 

author do not appear to me very reliable, but I notice that he does 

not ascribe to chouteauensis the concentric striae which are a feature 

of S. peculiaris, of my specimen from the Chouteau limestone, and 

probably of the specimen from the St. Joe limestone here under consideration.

Horizon and locality. St. Joe limestone member of the Boone limestone, St. Joe, Ark.

SPIRIFER sp.

Under this title are included a number of imperfect specimens 

which show neither the fine, radial striae of S. grimesi nor the concentric lamellae of S. vernonensis, though in a few the preservation is 

such that one would expect some trace of sculpture to be retained. 

There may be, in fact, more than a single species among these shells, 

but at present there is no way to distinguish them satisfactorily.

Horizon and locality. St. Joe limestone member of the Boone limestone, St. Joe, Ark.

SYRINGOTHYRIS CARTER: Hall.

It has always been difficult to distinguish species satisfactorily 

amo.ng representatives of the genus Syringothyris, and I have not 

been able to satisfy myself as to the affinities of the three not very 

perfect specimens found at St. Joe. The largest of these when complete had a width of about 60 millimeters; the length of the dorsal 

valve must have been about 45 millimeters, and the height of the 

ventral area about 30 millimeters. The area is gently concave and 

must have been rather strongly inclined forward. The costse are 

large, few, and ill defined.

Since the chief distinguishing character of the Fern Glen species 

Syringothyris sampsoni mentioned by Prof. Weller is the height of 

the area, it is probable that the present form is riot S. sampsoni, for 

the height of its area is only about half as great. It seems to be 

rather more in agreement with S. carteri than with any other species, 

though many of its characters are not well shown. It resembles 

S. Tialli in the inclination of the area (though this relation is obscured 

by crushing in the best preserved example), but it is much larger.

Horizon and locality. St. Joe limestone member of the Boone limestone, St. Joe, Ark.
40 FAUNAS OF THE BOONE LIMESTONE AT ST. JOE, ARK.

RETICULARIA COOPERENSIS Swallow.

A ventral valve from one of the collections undoubtedly belongs to 

a species of Reticularia and is at present indistinguishable from 

R. cooperensis from the Chouteau limestone. In a second collection, 

probably made at the same place, there are three small spiriferoid 

ventral valves which are also referred to the same species, but three 

small dorsal valves are included with more doubt. If specimens are 

exfoliated and imperfect, especially dorsal valves, it is often impossible to distinguish satisfactorily Reticularia, Cliothyridina, and sometimes Athyris and Composita. Yet, though some doubt surrounds the 

identification of individual specimens, my material is sufficiently perfect to show the presence of three out of the four genera, and to 

permit a reasonably accurate determination of the species.

Horizon and locality. St. Joe limestone member of the Boone limestone, St. Joe, Ark.

AMBOCGELIA MINUTA White.

This species is represented by a single rather well preserved specimen. The dorsal valve is nearly flat, subquadrate or subcircular, 

slightly wider than long. The. size is small, the width being only 4 

millimeters. The ventral valve is moderately elevated, suberect, 

somewhat projecting behind the hinge line. A gentle sinus is developed in both dorsal and ventral valves.

The specific differentiation among the AmbocoBlias is very slight, 

and the validity of some of the species that have been described from 

the Carboniferous is open to question. The genus appears to be more 

common in the Pennsylvanian than in the Mississippian and more 

common in the lower Mississippian than in the upper. From the 

early Mississippian we have A. levicula, A. minuta, and A. parva. The 

present specimen differs from A. levicula in having much shallower 

sinuses, and it differs from A. parva in not having the sinus of the 

ventral valve narrow and groovelike. It differs from A. arcuata in 

being relatively broader. The most numerous points of agreement 

appear to lie with A. minuta, than which, however, it seems to be 

considerably larger.

Horizon and locality. St. Joe limestone member of the Boone 

limestone, St. Joe, Ark.

ATHYRIS HANNIBALENSIS Swallow.

This species is represented by several rather well preserved specimens which agree exactly with Athyris Jiannibalensis from Louisiana, 

Mo. The shape is subpentagonal or subrhomboidal, slightly wider than 

long, and the surface is crossed by a number of distantly and regularly 

disposed lamellae.
THE ST. JOE LIMESTONE MEMBER. 41

This species is rather clearly the same that is found in the Fern 

Glen fauna and that Prof. Weller identifies as Aihyris lamellosa. So 

far as my observations go, however, this type can be distinguished 

from the more transverse one occurring at the higher horizon which is 

usually referred to A. lamellosa. This view is apparently shared by 

Prof. Weller, as he does not include A. Jiannibalensis in the synonymy, 

but it is the narrow not the broad form that he refers to L'Eveille^s 

species. Typical lamellosa as depicted in L'Elveille's figures is a 

broad type more like the Keokuk and Waverly variety, and if 

lamellosa occurs in this country at all it is to these that the name 

should be applied, unless, indeed, the whole series of forms is to be 

merged in a single species.

Horizon and locality. St. Joe limestone member of the Boone 

limestone, St. Joe, Ark..

CLIOTHYRIDINA ROISSYI Weller non L'fiveille". 

Plate II, figures 7-9.

A single small, lenticular athyroid (length and breadth 9 millimeters) shows a surface covered with fine, closely arranged lamellae, 

from which presumably proceeded fringes of spines. A second 

specimen from the other collection is too exfoliated to retain any of 

the surface characters, but it has a similar subcircular shape, though 

more transverse, .and a size nearly twice as great.

These shells without much question belong to the species which 

Prof. Weller calls OliotJiyris royssii, the correct or at all events the 

authentic spelling of which is Spirifer .roissyi. Typical roissyi, as 

figured by L/'Eveille", is a quite different sort of shell, being much more 

strongly transverse and having a highly developed fold and sinus. 

In fact,L'E)vei!16's figuresof roissyi so closely resemble those of Spirifer 

(Atliyris) lamellosus as to arouse the suspicion that they represent 

specimens belonging to the same species though differing somewhat 

in preservation and to a minor degree in shape. At all events it is 

not Prof. Weller's C. roissyi that resembles the authentic one, but 

a species which he, doubtless correctly, refers to CliotJiyridina prputi. 

I do not know what name would best be employed for this species, 

but it is clearly not roissyi. Perhaps it only consists of young examples of the larger form, C. incrassata Hall.

As this species is so persistently misunderstood by American 

authors, and as the original work is difficult of access, I have 

reproduced (see PI. II, figs. 7, 8, and 9) the original figures of L'Eveill6 

for comparison with our own forms.

Horizon and locality. St. Joe limestone member of the Boone 

limestone, St. Joe, Ark.
42 FAUNAS OF THE BOONE LIMESTONE AT ST. JOE, ARK.

COMPOSITA? Sp.

Under this head I am including a very small, rather slender ventral 

valve only about 4 millimeters long. The shell substance appears to 

be impunctate, so that it is not a terebratuloid. The surface is exfoliated and the sculpture destroyed, but the shape is much more like 

that of Composita than Athyris or Cliothyridina, both of which 

genera are known in the same beds. It resembles Composita madisonensis var. pu&illa, but is much smaller and has a stronger sinus.

Horizon and locality. St. Joe limestone member of the Boone 

limestone, St. Joe, Ark.

GASTROPODA.

PLATYCERAS NASUTUM Miller?

This species is represented by two mature, fairly perfect specimens 

and by three others which are smaller and more fragmentary. The 

extreme antero-posterior dimension is 27 millimeters. The small 

apex is closely coiled on itself, making perhaps a complete volution, 

below which the expansion is very rapid (varying, however, in 

different specimens) and the curvature slight (about one-half turn). 

The conspicuous feature of the configuration is an angulation or ridge 

running down the anterior side. In one specimen this is emphasized 

by a groove extending lengthwise to the left of the angulation, and 

in both specimens it is indicated by strong flexures of the growth 

lines, which produce an emargination of the peristome at the ridge 

and a slight projection each side of. it. The growth lines are sinuous on both sides of the ridge, indicating small, ill-defined costse 

which are scarcely perceptible as elevations. Rather strong, regular 

incremental striae are present.

These shells agree with P. nasutum in some important particulars, 

such as the ridge down the anterior side and the emargination and 

sinus at the anterior margin. They differ from it chiefly in having 

the aperture less elongated than that of the type specimen (a.difference of no great moment as the two St. Joe specimens differ markedly 

from one another) and in displaying flexures of the growth lines and 

obsolete plications not mentioned in the description of P. nasutum. 

The St. Joe specimens resemble P. paralius as figured by Prof. Weller 

from the Fern Glen limestone, fairly well in size and shape, and particularly in the fine obscure costae and the correlated denticulations 

at the margin, but differ in having a less regularly circular or oval 

aperture and especially in developing a plication down the anterior 

side and the emargination going with it.

Horizon and locality. St. Joe limestone member of the Boone 

limestone, St. Joe, Ark.
PLATE I.

43
PLATE I.

PRODUCTELLA PATULA (p. 13).

FIGURE 1. Dorsal view of a specimen retaining both valves, 

la. Ventral view of same. 

Ib. Side view in outline.

2. External mold of a dorsal valve. , 

Lower part of the Boone limestone, St. Joe, Ark.

PRODUCTELLA CONCENTRICA (p. 11).

FIGURE 3. A small ventral valve, X 4. 

3a. Same in outline, natural size. 

3b. Side view in outline, natural size.

Lower part of the Boone limestone, St. Joe, Ark. f

CHONETES ORNATUS var. ARKANSANUS (p. 11.) *

FIGURE 4. A ventral valve, X 4.

4a. Same in outline, natural size. *

Lower part of the Boone limestone, St. Joe, Ark.

PRODUCTELLA MILLESPINOSA (p. 14).

FIGURE 5. A typical ventral valve. 

5a. Same, X 2.

5b. Side view, X 2. V 

5c. Same in outline, natural size.

Lower part of the Boone limestone, St. Joe, Ark. '

PRODUCTELLA SEMICOSTATA (p. 12).

FIGURE 6. A characteristic specimen with both valves in conjunction, broken in

two along the plane of the dorsal valve. This figure shows the ventral ^ 

valve (with the two parts in contact) viewed from above, X 2. 

6a. Same in outline, natural size. \ 

6b. Side view in outline. ' 

6c. Anterior view, X 2. 

6d. The visceral area of the dorsal valve, as an external mold, exposed by

the removal of the "cap," natural size. 

7. A malformed ventral valve, X 2.

7a. Same in outline? natural size. ^* 

7b. Side view in outline.

7c. Anterior view, X 2. * 

Lower part of the Boone limestone, St. Joe, Ark.

RHYNCHOPORA PINGUIS (p. 15).

FIGURE 8. Ventral view of the typical specimen. 

8a. Dorsal view.

8b. Side view. *

8c. Anterior view.

Lower part of the Boone limestone, St. Joe, Ark. 

44
U. S. GEOLOGICAL SURVEY BULLETIN 598 PLATE I

la

Ib

X 4

3b

8a

FOSSILS FROM THE BOONE LIMESTONE. 

BRACHIOPODA.

8c
PLATE II.

45
PLATE II.

SPIRIFER CARINATUS? (p. 17).

FIGURE 1. Dorsal view of the only specimen found. 

la. Side view in outline. 

Ib. Ventral view.

Lower part of the Boone limestone, St. Joe, Ark.

SPIRIFERINA aff. SPIRIFERINA SUBTEXTA (p. 18).

FIGURE 2. A ventral valve.

2a. Side view in outline.

Lower part of the Boone limestone, St. Joe, Ark.

CYPRICARDINIA RUGOSA (p. 20).

FIGURE 3. Right valve of a bivalved specimen, X 3. 

3a. Same in outline, natural size. 

3b. Left valve of same, X 3. 

3c. Same in outline, natural size.

Lower part of the Boone limestone, St. Joe, Ark.

CARDIOMORPHA ORBICULARIS (p. 21).

FIGURE 4. A right valve, X 2.

4a. Same in outline, natural size.

5. A small left valve provisionally referred to the same species, X 2. 

5a. Same in outline, natural size.

Lower part of the Boone limestone, St. Joe, Ark.

BRACHYMETOPUS? ELEGANS (p. 22).

FIGURE 6. A pygidium somewhat broken at the margin.

6a. The same, enlarged to two diameters and restored, X 2. 

Lower part of the Boone limestone, St. Joe, Ark.

CLIOTHYRIDINA ROISSYI (p. 41).

FIGURES 7, 8, 9. These are figures 18, 19, 20, respectively, of L'Eveill^'s Spiriferde 

roissyi (Soc. ge"ol. France Me"m., vol. 2,1835, pi. 2, figs. 18,19, 20). 

They show a species quite distinct from the American shells 

commonly identified with this species, and one would not suspect 

that they represented a Cliothyridina at all. They suggest a 

Compoaita related to our C. trinudea, and they so exactly resemble 

the figures of Spirifer (Athyris) tamellosus, given just below as to 

arouse suspicions that they represent only an exfoliated condition 

of the Athyris.

CAMAROPHORIA SIMULANS (p. 35).

FIGURE'S 10,'lOa, lOb, lOc. Four views of one of the type specimens.

11, lla, lib. Three views of another of the type specimens. Fig. 11 is 

enlarged 1£ times to show the spondylium.

St. Joe limestone member, St. Joe, Ark. 

46
U. S. GEOLOGICAL SURVEY BULLETIN 598 PLATE I

CD

3a

X 3

5a

o

3c

4a

lOb

lOc

lOa

lla

FOSSILS FROM THE BOONE LIMESTONE. 

BRACHIOPODA. PELECYPODA. AND TRILOBITA.

10

lib
PLATE III.

47
PLATE III.

FlSTULIPORA RUBRA (p. 30).

FIGURES 1, 2, 3. Three sections cutting the cells longitudinally, X 10. Owing to the 

contorted growth of these colonies it is very difficult to obtain 

sections which follow the zooecia for any distance.

4, 5. Two sections cutting the cells transversely, X 10. Figures 1 and 4 

are based on sections from one specimen, figures 3 and 5 from 

another, and figure 2 from a third.

St. Joe limestone member, St. Joe, Ark. 

48
U. S. GEOLOGICAL SURVEY

BULLETIN 693 PLATE I

FOSSILS FROM THE BOONE LIMESTONE. 

BRYOZOA.
INDEX.

A.

Page.

Ambocoelia levicula. ..'...................... 40

minuta. ................................. 40

parva. ................................... 40

Amplcxns bicostatus. ....................... 8

brwis.. ................................. 29

fragiiis..... ............................... 7-8

rugostis.................................. 29

Athyris hannibalcnsis .................... 19, 40-41

lamellosa. ............................... 19, 41

B.

13oone limestone, age and subdivisions of. ...

fauna of lower part of. ...................

Brachiopoda......... .................. 11-19,

Brachymetopus clcgans. .................. 22-

Bryozoa. ............................... S-11,

Camarophoria simnlans.... . .................

Camarotcechia aff. C. cooperensis. ........;..

metallica. ...............................

n . sp ....................................

Cardiomorpha orbicularis. ...................

subglobosa. .............................

Cephalopoda................................

Cheilotrypa sp. ..............................

Chonetes illinoisensis ........................

ornatus..................................

var. arkansanus. ....................

Chouteau limestone, correlation of ...........

Cladochonns americanus.....................

Cliothyridina hirsuta. . ......................

incrassata. ..............................

prouti...................................

roissyi. ............................... 19,

Ccelenterata............................. 7-8,

Coelcnautilussp.............................

Composita madisonensis var. pnsilla. ........

sp .......................................

Crinoidal remains............................

Cyathaxonia arcuata. .......................

minor. ..................................

Cypricardiniaconsimilis.................. ...

fayettevillensis ..........................

rugosa. ..................................

Cystodictya lineata. .........................

lineata var. major .......................

D. 

Dielasma fernglenensis. ......................

sp.......................................

. Echinodermata. ....................

Euactinopora quinqueradiata. ......

49776° Bull. 598 15

5-6

6-7 

33-42 

23, 46^ 

30/33

35. 46

36. 37

35-36

36

21, 46

21

22

32

33 

11

11, 44

27-28 

30 

19

19, 41 

41

41, 46

28-30 

22 

42 

42 

30 

29 

29 

20 

20

20, 46 

8, 31

31-32

38

38

30

32

F.

Page. 

Fenestella cavernosa......................... 9

herrickana................................ 9,32

rudis.................................... 9

sp. a..................................... 9,33

sp. 6, c, d, and c. ...................... 9-10,33

Fistulipora fernglenensis..................... 31

rubra................................. 30-31,48

Gastropoda............................... 21-22,42

IT.' 

Hemitrypa n. sp............................. 10-11

" L.

Leptfena analoga............................ 11,33

P.

Pelecypoda.................................. 20-21

Platyceras equilatera........................ 21-22

nasutum................................ 42

paralius................................. 42

Polypora biseriata........................... 33

n. sp.................................... 10

sp....................................... 33

Productella concentrica............. 11-12,13,34,44

costulata................................ 14

hirsutiformis............................ 13

millespinosa...............'.............. 14,44

patula................................... 13,44

pyxidata................................ 34

semicostata........................... 12-13,44

Productus bnrlingtonensis................... 14-15

concentricus............................. 12

cooperensis.............................. 12

fernglenensis............................. 14

indianensis ............................... 12

levicosta................................. 34

pyxidatus............................... 12

sampsoni................................ 34

shumardianus........................... 12

R.

Reticularia cooperensi.s...................... 40

pseudolineata............................ 17-18

Rhipidomella burlingtonensis............... 35

michelini................................ 35

llhynchonella missouriensis................. 37

striaticostata...........................'. 37,38

Rhynchopora beecheri....................... 15,37

pinguis............................... 15-10,44

pustulosa................................ 37

sp........................................ Ifi, 37

Rhynchotetra caput-testudinis.............. 36

49
50 INDEX.

S. Page.

St. Joe limestone member, collections from... 24,

25,26 

composition of....... ^................... 25

correlation of............................ 27-28

Schizophoria swallowi........................ 15,35

Shumardiella missouriensis............... 35,37-38

Spirifer carinatus............................ 17,46

chouteauensis........................... 38,39

fernglenensis............................. 38

grirnesi............................... 16,38,39

lamellosus............................... 41

peculiaris................................ 33-39

pikensis................................. 17

sp....................................... 39

Page.

Spirifer suborbicularis...................... 16

vernonensis............................. 39

Spiriferina afl. S. subtexta................ 18-19,,46

clarksvillensis........................... 18,19

solidirostris.............................. 18,19

subtexta................................. 18,19

Syringothyris carteri........................ * 39

halli..................................... 39

sampsoai................................ 39

T.

Trilobita..............................'...... 22-23

Z.

Zaphrentis aff. /. dalei...................... 28

sp....................................... 29

o