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2 • UNIVERSITY OF

ILLINOIS LIBRARY

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GFOLOGY

FIELDIANA
Geology

Published by Field Museum of Natural History

Volume 30, No. 4 June 30, 1975

Caryocrinitidae (Echinodermata: Rhombifera)
of the Laurel Limestone of Southeastern Indiana

T. J. FREST

Research assistant

Indiana University Northwest

Gary. Indiana

INTRODUCTION

In a series of papers Miller (1892, 1894), Miller and Gurley
(1895), and Springer (1926) described a large echinoderm fauna
from the Laurel Limestone (Middle Silurian: Wenlock) in south-
eastern Indiana. Nearly all of their specimens are recorded as
coming from near St. Paul, Decatur County.

While the fauna is dominated by crinoids, Bassler and Moodey
(1943, p. 44) list three caryocrinitid cystoids, all of which were
originally placed by Miller in his family Stribalocystitidae and in
the genus Stribalocystites. The occurence of a fourth caryocrinitid
at St. Paul is mentioned by Miller and Gurley (1894, p. 11) in their
description of the Osgood species Caryocrinites ellipticus.

None of Miller's or Springer's material was personally collected:
the bulk of it was donated by the Doctors Howard, C. C. Wash-
burn, A. C. Benedict, W. F. E. Gurley, and H. E. Wilson (Springer,
1926, pp 6-7). Most of the types of Miller and Miller and Gurley,
as well as the collections of the Howards, Washburn, Benedict, and
Wilson are now housed in Field Museum of Natural History.
Springer's specimens are housed in the U. S. National Museum.

Miller's occasionally ambiguous descriptions and the lack of new
material have rendered the systematic position of Stribalocystites
somewhat uncertain. The genus was recognized by Bassler (1938),
but not by Bassler and Moodey (1943), and only provisionally by

Library of Congress Catalog Card Number: 74-33056

The Library of the

Publication 1203 _ _ ^ _ „

81 OCT 01 1975

_~w llnluercitv of Illinois

82 FIELDIANA: GEOLOGY, VOLUME 30

Springer (1926) and Kesling (1967). Examination of the old
collections and of new material I have collected has considerably
expanded the size of the Laurel cystoid fauna and has clarified the
status of Miller's species.

At least six species of Caryocrinites have been collected from the
Laurel. The Laurel forms appear to be highly endemic: only one,
C. stellatus n. sp., is known to occur outside of the formation (Joliet
Dolomite of Illinois). None of the Laurel species appears to be
closely related to those found in the underlying Osgood or in the
Waldron Shale, which succeeds the Laurel in most of its outcrop
area. The lack of definite antecedents or descendents of the Laurel
forms indicates that a number of species of this already extraordin-
arily large cystoid genus remain to be discovered.

I would like to thank Dr. Eugene S. Richardson Jr., Field Muse-
um, and Mr. Carl Armstrong, Indiana State Museum, for access to
and loan of specimens under their care; and Dr. C. R. C. Paul,
Liverpool University, and Dr. R. Kesling, University of Michigan,
for critically reviewing the manuscript. All specimens unless
otherwise noted are deposited in Field Museum (FMNH).

STRATIGRAPHY

The Laurel Limestone (Laurel Member, Salamonie Dolomite, of
Pinsak and Shaver (1964)) is extensively exposed in southeastern
Indiana. Most outcrops are totally unfossiliferous and dolomitic. In
a few places, however, notably near St. Paul and Sandusky,
Decatur County, Indiana (Frest and Paul, 1971, p. 425), the Laurel
is richly fossiliferous. The fauna is mostly echinoderms (cystoids,
crinoids, blastoids, and cyclocystoids), but other invertebrates
(notably corals, trilobites, and brachiopods) are frequently found.

Caryocrinitid cystoids were collected from loose material and in
place by the author from two localities in the vicinity of St. Paul.
The majority of specimens were found in the abandoned Adams
Quarry, 0.2 miles SE of St. Paul (SWV* SWW SWVi sec. 3, T 11 N,
R 8 E, Waldron IVz quadrangle), but well-preserved cystoids were
also collected from an active quarry owned by the St. Paul Stone
Co., Inc., located in the center of the NEx/4 of sec. 9, T 11 N, R 8 E,
Waldron 1V% quadrangle, 0.6 miles SW of St. Paul. The former
locality is believed to have been the source of Miller's and
Springer's material (Springer, 1926, p. 6). There are several other
small disused quarries in the vicinity, but these proved practically
barren. At both localities identifiable fossils were found only in the
upper 20 ft. of the Laurel. A section of the rocks exposed in the

UNIT

LITHOLOGY

RANGE

rz

iii

TZL

zs^

^gg

mm^

*g&gZ2B

I I I I

III/-

I'll

III!

DOLOMITIC LIMESTONE

ARGILLACEOUS DOLOMITIC
LIMESTONE

CHERTY ARGILLACEOUS
LS. & DOLOMITIC LS.

SHALE

SCALE

1 V, 0 1 2 3 FT.

* ■ * ■ *

<S-, f f. «*?■>■,» I .». l*V jWf I , r. I >r.*?T»ri^ . !**.

Pig. 1. Stratigraphic section of the Laurel Limestone exposed at the Adams
Quarry, SE of St. Paul, Indiana. The term "Stribalocystites" includes the small
thick-plated species C. sphaeroidalis (Miller) and C. stellatus n. sp. "Caryocri-
nites" refers to the larger forms C. laurelensis n. sp. and C. tribrachiatus n. sp.
Ranges compiled from occurences at both the Adams Quarry and the St. Paul
Stone Co. quarry localities.

83

84 FIELDIANA: GEOLOGY, VOLUME 30

Adams Quarry is given as Figure 1 ; the upper part of the section in
the active quarry is virtually identical. As the Adams Quarry was
expanded considerably in the period 1921-1926 before closing down
permanently, the section is considerably different from that record-
ed from the same locality by Foerste (1897, pp. 230-231).

This section differs considerably not only from that of the typical
Laurel but also from the section at Sandusky described by Frest and
Paul (1971, fig. 1). It is suggested on the basis of combined litho-
logic and paleontologic data that unit 1 of the Adams section is
equivalent to the Pisocrinus-bearing strata at the top of the east
face of the Sandusky quarry. Thus the strata containing Caryo-
crinites occur at a level approximately 10 ft. below the bottom of the
unit in which Callocystites brevis was found.

PALEOECOLOGY

The Laurel caryocrinitids may be encountered at any level in
units 2 and 3 and in the upper 18 in. of unit 4. The small, thick-
plated types are especially common near the middle of unit 3 and in
the highly argillaceous beds near the top of 4. This is also the
source of most of the crinoids described by Springer and Miller.
The larger form, C. laurelensis n. sp., occurs throughout but is
especially common near the top of unit 2 .

The dominant lithologic type is a shaly dolomitic bioclastic lime-
stone composed largely of micritized echinoderm plates and ossicles
and occasional whole specimens. Contacts between units are
sharp but within each there are highly local variations in grain size
and amount of elastics and in the size of fossil particles. Whole
thecae generally occur in small patches of coarser debris accumu-
lated in slight depressions on bedding surfaces. Frequently in-
place root systems and still articulated lengths of crinoid stem are
associated with these patches. While complete crowns are
exceedingly rare, the distance of transport, if any, was small.

In a study of the petrography of the Silurian rocks of southeastern
Indiana and southwestern Ohio, Priddy (1939) concluded that the
typical Laurel was deposited in about 500 ft. of water and the
more clastic formations, such as the Osgood, at a depth of around
150 ft. An intermediate figure is likely for the fossiliferous Laurel
localities. Although the number of Laurel localities with abundant
fossils is too small for the evidence to be conclusive, fossil
distribution in the Laurel appears to be influenced by the "Ripley
Island" positive area of Foerste (1904, p. 325). Similar control of
fossil distribution has been noted by Kindle and Barnett (1909) for

FREST: CARYOCRINITIDAE 85

the Waldron Shale and is described in detail by Paul (1971, pp.
33-37, fig. 11) for the Holocystites fauna of the Osgood. My field
work in 1970-1971 suggests that the proportion of terrigenous
material in the Laurel is considerably higher in the area adjacent to
and including the "island."

Indicators of strong current activity, such as crossbedding, are
absent, as are biogenic sedimentary structures. Both sedimento-
logical and paleontological evidence suggest a quiet and relatively
barren soft sea floor with small but dense patches of echinoderms
scattered over the bottom in favorable locations. Currents were
weak but persistent and the sedimentation rate was slow. Indi-
vidual stands probably did not persist for long, but in toto were
the primary organic contributors to the accumulating deposit. The
rarity of other marine invertebrate groups which are abundant in
most fossiliferous Paleozoic rocks (e.g., brachiopods and corals), in
addition to the evidence cited above, suggests a moderately deep-
water environment.

SYSTEMATIC DESCRIPTIONS

Class Rhombifera Zittel 1880 nom. trans. Paul 1972

Order Dichoporita Jaekel 1899 emend. Paul 1972

Superfamily Hemicosmitida Jaekel 1918

Family Caryocrinitidae Bernard 1895 emend.

Definition— Rhombiferan cystoids comprising the family Caryo-
crinitidae have a theca composed of three circlets of plates (fig. 2)
which are probably homologous with the basals (B, plural BB),
infra-laterals (IL,ILL), and laterals (L,LL) of the Glyptocystitida,
plus a variable number of tegminals (T,TT) covering the adoral
portion of the theca. The family is distinguished from the Hetero-
cystitidae by the possession of only six ILL, and from the Hemicos-
mitidae by the lack of a radial circlet, the position of the periproct,
and the possession of a tegmen and three hypothecal food grooves.
It also differs considerably from the monotypic family Thomacysti-
dae which has three basals, an "adoral" circlet, no tegmen, and
four epithecal food grooves (Paul, 1969). Well-known genera have
a constant plate formula in the first three circlets: four BB, six ILL,
and eight LL. The brachiole facets, variable in number, are
distributed around the lateral edge of the tegmen, which covers
both the peristome and ambulacral tracts. The periproct is high on
the adoral portion of the theca either completely surrounded by

86

FIELDIANA: GEOLOGY, VOLUME 30

10

FIG. 2. Thecal plate arrangement of the first three circlets in Caryocrinites.
B1-B4 = basals; IL1-IL6 = infralaterals; Ll-L8 = laterals. Curved lateral sutures
indicate positions of ambulacral facets in C. ornatus Say. The position of the peri-
proct is indicated by a circle; that of the gonopore by an arrow.

the tegminals or between them and the LL. Cryptorhombs are
developed on the first three circlets. Each dichopore (canal)
terminates on the surface of the theca in two external pores, one of
which is a simple opening while the other is expressed as a sieve-
like group of tiny pores.

Caryocrinites Say 1825

Caryocrinites Say, 1825, Jour. Acad. Nat. Sci. Phil., 4, p. 289.

Cariocrinites (sic) Say, Bronn, 1834, Lethaea Geognostica, p. 64.

Caryocrinus (sic) Say, Agassiz, 1836, Mem. Soc. Neuchatel, l,p. 198.

Cariocrinus (sic) Say, Austin and Austin, 1845, Mon. Rec. Foss. Crin., p. 53.

Caryocrinus Say, Hall, 1852, Nat. Hist. N.Y., pt. 6, 2, pp. 216, 248.

Caryocrinus Say, Zittel, 1880, Hanb. Paleontol., 1, p. 418.

Stribalocystites Miller, 1892, 17th Ann. Rept., Geol. Surv. Ind., p. 630.

Ennaecystis Haekel, 1896, Amphor. Cyst., p. 143.

Stribalocystites Miller, Jaekel, 1899, Stammes. Pelmat., 1, p. 313.

Caryocrinites Say, Jaekel, 1899, Stammes. Pelmat., 1, p. 312.

Caryocrinus Say, Bather, in Lankaster, 1900, Treatise Zool., 3, p. 28.

Caryocrinus Say, Grabau, 1901, N.Y. State Mus., Bull. 45, p. 149.

Caryocrinus Say, Bather, in Reed, 1906, Paleontol. Indica., n.s., Mem. 2(3), p. 28.

Caryocrinus Say, Springer, in Zittel-Eastman, 1913, Textb. Paleontol., 1, p. 163.

Caryocrinus Say, Foerste, 1916, Ottawa Natur., 30, p. 110.

Stribalocystites Miller, Springer, 1926, Smithsonian Inst., Misc. Pub. 2871,

p. 142.
Stribalocystites Miller, Bassler, 1938, Foss. Cat., Animalia, pars 83, p. 176.

FREST: CARYOCRINITIDAE 87

Caryocrinites Say, Bassler and Moodey, 1943, Geol. Soc. Amer., Spec. Paper

45, p. 137.
Caryocrinites Say, Kesling, in Moore, ed., 1967, Treatise Inver. Paleontol., pt.

S, 1, p. S223.

Type species. —Caryocrinites ornatus Say 1825.

Diagnosis. —A genus of Caryocrinitidae with an ovoid to elongate
theca, four BB, six ILL, eight LL, and a variable number of tegmin-
als (figs. 3, 4). Brachiole facets vary in number but are always ar-
ranged in three distinct groups. The oral surface is flat to gently
convex and the three ambulacral grooves and the mouth are roofed
over by a well-developed tegmen.

Remarks. —The single most important feature distinguishing the
Caryocrinitidae from the Hemicosmitidae is the presence in the
former of a well-developed tegmen. The caryocrinitid tegmen is a
functional analogue to that of crinoids, although the plates of which
it is composed probably are analogous to some of the ambulacral
covering plates of other cystoids, notably to the palatals of the
Sphaeronitidae and the Holocystitidae (Paul, 1971, pp. 6-7). In
recognition of the considerable differences between this structure
and that present in the other diploporite cystoids mentioned above
and the often-noted crinoid-like features of Caryocrinites, the term
"tegmen" is retained for this family. The individual plates collect-
ively comprising the tegmen are herein termed "tegminals" (T,
plural TT).

The system of numbering plates used here is the same as that
used by Paul (1969, p. 194) for the genus Thomacystis: the plates of
each circlet are numbered consecutively starting from the left of the
gonopore and proceeding clockwise around the theca. The
presence of the gonopore on the tegminal adjacent to the periproct
on its left side has been noted in three species (C. ornatus, C.
persculptus, and C. laurelensis n. sp.). The hydropore is a small,
round opening developed on the tegmen immediately above the
anal opening in C. ornatus (figs. 3b, 4). Neither of these two thecal
orifices is evident in the other species described herein.

The unique nature of the caryocrinitid tegmen necessitates the
use of different nomenclature than that employed for the "orals" of
the Glyptocystitida or other hemicosmitid cystoids. While the com-
position of the tegmen is known to change during ontogeny in at
least one species (C. ornatus), the number and disposition of the
tegminals in the adult are fairly constant and differ in only minor
respects from specimen to specimen in the three species which are

FREST: CARYOCRINITIDAE

89

a

Fig. 4. Diagrammatic representation of the plate arrangement of the tegmen of
a, Caryocrinites ornatus Say, and b, C. persculptus Springer. C-central: peri-
centrals numbered consecutively 1-8; A-anus; G-gonopore; H-hydropore. Ambu-
lacral facets dotted.

represented in museum collections by large numbers of individuals
(C. ornatus, C. kentuckyensis, and C. sphaeroidalis) . The theoreti-
cal number of possible arrangements is quite large and a wide
range is encountered among the score or so of species ascribed to
the genus. Because of the high specificity and taxonomic utility of
the tegmen, more emphasis is placed upon its characters herein
than formerly was the case. The terminology defined below is
illustrated diagrammatically in Figure 5.

A single plate, the central (C) covers the mouth. It is surrounded
by a circlet of eight plates, termed pericentrals (Pc, plural Pec),
which are numbered consecutively in the same manner as those of
the other circlets. Thus Pc 8 bears the gonopore and Pc 7 the
hydropore. The ambulacral grooves pass beneath pericentrals 1,3,
and 5; 2, 4, and 6-8 occupy interambulacral positions. The peri-
proct is surrounded by Pec 6-8 and occasional accessories. In some

Opposite.

Fig. 3. a,b, Caryocrinites ornatus Say, FMNH PE 27881 . a, lateral view; b,
oral view to show tegmen, gonopore, and hydropore. c,d, Caryocrinites persculp-
tus Springer, FMNH PE 27882. c, lateral view; d, oral view. e,j, Caryocrinites
laurelensis n. sp., holotype (FMNH PE 19172). e, anterior lateral view to show
plate arrangement; f, posterior lateral view to show periproct; g, left lateral view
to show cryptorhombs and ambulacral facets; h, right lateral view; i, oral view to
show tegmen; j, basal view to show column facet. All X 1.5, whitened with
ammonium chloride sublimate.

90 FIELDIANA: GEOLOGY, VOLUME 30

Fig. 5. Diagrammatic representation of the tegminal plate arrangement in the
genus Caryocrinites Say. Ll-8 = laterals; Pec numbered consecutively 1-8. A-
anus; G-gonopore; H-hydropore ; C-central. Facetals dotted, accessories black.
Heavy line indicates periproct border.

species LL 7 and 8 also form part of the periproct border. Other
accessories are often disposed symmetrically between pericentrals
1, 3, and 5 and thr brachiole facets. The branches of the main
ambulacral grooves undoubtedly pass beneath some of these.
Unlike the C and Pec, accessories vary somewhat in position and
number.

Bordering the pericentrals are the facetals (F, FF). In all species
examined each brachiole facet is developed on a pair of plates, with
separate openings for the ambulacral tract and the radial nerve
positioned on the suture between the pair. In a few species an ad-
ditional pore is developed on the facetal to the right or left of the
brachiole facet. These pores are believed to have borne small
brachioles or pinnules performing a sensory function. Unlike the
pericentrals, which often form a closed circlet, the facetal circlet is
usually disrupted. Pec 2 and 4 are commonly in contact with LL 2
and 5. All eight Pec seldom abut the central. Pc 1, 3, 5, and 6 are
most frequently out of contact with the central plate.

Caryocrinites laurelensis new species. Figures 3e-j, 6, 7e.

Diagnosis. —A species of Caryocrinites of medium-to-large size
with six brachiole facets and facetal circlet closed except where
periproct intrudes.

Type. -FMNH PE 19172 (holotype).

FREST: CARYOCRINITIDAE 91

Material. —Eight complete thecae and many isolated plates.
FMNH.

Horizon and locality. —The holotype is from the top of unit 2 at
the Adams Quarry. Other specimens came from beds 2 and 4 at the
same locality and also from unit 3 at the St. Paul Stone Co. quarry.

Description. —

THECA: Subspheroidal with large basals and wide stem facet.
Dimensions of holotype: height 18.6 mm., diameter 17.4 mm. Iso-
lated plates suggest a maximum height of over 30 mm. Height/
diameter ratio 1.07.

PRIMARIES: BB 1 and 4 large, equal, hexagonal, H/W ratio 0.77.
Ornamentation consists of two thin, sharp ridges and sporadically
developed secondary ridges parallel or normal to edges of the plate,
rest of plate surface smooth or finely granular. BB 2 and 3 narrow,
equal, pentagonal, H/W ratio 1.18, ornamented with one central
lengthwise ridge and rare secondaries. Ridges on BB coalesce at
base to form a raised, square platform into which the column facet
is indented. Column facet round, diameter 4.23 mm.

ILL 1, 5 equal, nearly regularly pentagonal, H/W ratio 1.22. ILL
2 and 4 equal, heptagonal, H/W ratio 1.38. All ILL with sharp,
radiating ridges to each corner, meeting in center of plate. Second-
ary ridges and nodes infrequent, most of plate covered with fine
granules and parallel growth lines. LL variable in size and shape,
large (average height 6.2 mm.). Ornamenting ridges developed

Fig. 6. Diagrammatic representation of the tegmen of Caryocrinites laurelensis
n. sp., based on the holotype. A-anus; G-gonopore; C-central; Pec numbered 1-8;
ambulacral facets dotted.

92 FIELDIANA: GEOLOGY, VOLUME 30

mainly on bottom half of LL, radiating aborally from the center to
corners.

Cryptorhombs regularly diamond-shaped, developed most exten-
sively along L-IL sutures, 13-19 dichopores per rhomb. B-IL crypto-
rhombs with seven dichopores. Simple pores found only on ILL.
No intra-circlet rhombs detected.

TEGMEN: Central heptagonal, in contact with Pec 2, 4, 5-8, and
one accessory. One accessory each associated with Pec 1, 3, and 5.
Brachiole facets six, large, centered on paired facetals, pore for
sensory brachiole developed on outer member of each pair. Face-
tals in contact except those adjoining periproct. Plates smooth or
slightly granular. Gonopore round, 0.33 mm. in diameter, on Pc 8
near suture with adjacent facetal. Tegmen about three-fourths of
thecal diameter.

Hydropore not observed.

PERIPROCT: Small, circular (2 mm. diameter), distinctly protrusive
from theca, bordered by Pec 6-8 and LL 7, 8.

Remarks. —This is the most abundant and wide-ranging caryo-
crinitid in the Laurel. Whole thecae are especially common near
the top of unit 2. Isolated plates decrease in abundance from unit 2
to the top of 4, where they are rare. Miller (1894, p. 10), in his des-
cription of the Osgood species C. ellipticus, mentions four speci-
mens of Caryocrinites collected by Gurley at St. Paul, commenting
that "they seem to differ only in bearing higher and sharper radiat-
ing lines." Six specimens of this species, all fragmentary or buried
in matrix, are registered in Field Museum (UC 15518) under the
name C. ellipticus and are labelled as being from Gurley 's collec-
tion. The incomplete nature of the specimens is probably respon-
sible for the misidentification. The type of C. ellipticus could not be
located, but a specimen from Gurley's collection (UC 53122) which
bears a label in Gurley's handwriting is illustrated for comparison
(figs. 7a-c, 8).

Opposite.

Fig. 7. a-c, Caryocrinites ellipticus Miller and Gurley (FMNH UC 53122). a,
oral view to show tegmen; b, basal view to show column facet; c, posterior lateral
view to show plate proportions and ornament, d, oral view of holotype of "Strib-
alocystites" {Caryocrinites) sphaeroidalis Miller (FMNH UC 6128), showing teg-
minal plate arrangement, e, infralateral plate of C. laurelensis n. sp. to show
simple pores and plate arrangement. FMNH PE 27825. a-c, X 2.5; d, X 3.4
approximately; e, X 4.0. All figures whitened with ammonium chloride sublimate.

93

94 FIELDIANA: GEOLOGY, VOLUME 30

Caryocrinites sphaeroidalis (Miller and Gurley). Figures 7d, 9,
lOa-f.

Stribalocystites tumidus Miller, 1892, 17th Ann. Rept., Geol. Surv. Ind., p. 630,

pi. 6, figs. 33-34.
Stribalocystites gorbyi Miller, 1894, 18th Ann. Rept., Geol. Surv. Ind., p. 265, pi.

2, figs. 3-8.
Stribalocystites sphaeroidalis Miller and Gurley, 1895, 111. State Mus., Bull. 6,

p. 58, pi. 5, figs. 19-21.
Caryocrinus gorbyi (Miller) Bather, in Reed, 1906, Paleontol. Indica, n.s., Mem.

2(3), p. 28.
Caryocrinus sphaeroidalis (Miller and Gurley) Bather, in Reed, 1906, Paleontol.

Indica., n. s. Mem. 2(3), p. 28.
Stribalocystites gorbyi Miller, Springer, 1926, Smithsonian Inst., Pub. 2871, p.

142, pi. 33, figs. 15-18.
Caryocrinites gorbyi (Miller), Bassler and Moodey, 1943, Geol. Soc. Amer., Spec.

Paper 45, p. 138.
Caryocrinites sphaeroidalis (Miller and Gurley), Bassler and Moodey, 1943, Geol.

Soc. Amer., Spec. Paper 45, p. 140.
Caryocrinites tumidus (Miller), Bassler and Moodey, 1943, Geol. Soc. Amer., Spec.

Paper 45, p. 140.

Diagnosis.— A caryocrinitid of small size (height: 4.14 mm.)
and variable shape with three brachiole facets, a very small tegmen
with only six plates in contact with the palatals, and unusually thick
tegminal plates.

Type.-"S. sphaeroidalis" FMNH UC 6128; FMNH PE 1917a, b
(two paratypes).

Material. —At least 150 complete thecae and numerous frag-
ments. FMNH and USNM.

Fig. 8. Diagrammatic representation of the tegmen of Caryocrinites ellipticus
Miller and Gurley, based on FMNH UC 53122. Pec numbered; C-central; A-anus.

FREST: CARYOCRINITIDAE 95

a b

Fig. 9. Diagrammatic representation of the tegmen of Caryocrinites sphaeroid-
alis (Miller and Gurley). a, oral view to show relative diameters of tegmen and
theca; b, enlargement of a, to show tegminals. A-anus; C-central; Pec numbered;
ambulacral facets dotted. Based mainly on paratype FMNH PE 19175b.

Horizon and locality. —Lower half of unit 2, the entirety of unit 3,
and upper 18 in. of unit 4, Laurel Limestone, Adams Quarry and St.
Paul Stone Co. quarry.

Description. —

THECA:Ovoid to subturbinate, with narrow, round stem facet
1.31 mm. in diameter. Holotype distorted: dimensions of paratype
FMNH PE 1917a, height 11.9 mm., diameter 9.07 mm., H/D ratio
1.20.

PRIMARIES: All plates thick, tumid, broadly convex with impres-
sed sutures. Ornamentation on well preserved specimens consists
of low, narrow ridges from corners of plates, merging in center.
Small, shallow, broadly rounded ridges often developed between
major ridges. Entire plate surface including ridges ornamented
with very small granules.

Basals small, forming broad shallow cone, BB 2 and 3 unusually
elongated. Dimensions of BB 1 and 4: height 3.73 mm., width 4.15
mm., H/W ratio 0.90; dimensions of BB 2 and 3; height 3.75 mm.,
width 3.02 mm., H/W ratio 1.24. Stem facet deeply excavated into
BB, small.

ILL 1 and 5 equal, subpentagonal, shorter sutures facing adjacent
heptagonal ILL, H/W ratio 1.16.

IL 2 and 4 equal, heptagonal, H/W ratio 1.12. ILL 3 and 6 narrow
hexagons, H/W ratio 1.28. LL smaller and less prominent than in
most species, widely variable in size.

Pores of cryptorhombs often evident only on ILL and seldom seen

96 FIELDIANA: GEOLOGY, VOLUME 30

on basals. No intra-circlet dichopores. Eleven dichopores usual in
adult L-IL rhombs. L-IL rhombs regular in shape: B-IL crypto-
rhombs appear to be developed irregularly and are sometimes
absent.

TEGMEN: Flat or gently curved, size somewhat variable: general-
ly about one-sixth greatest diameter of theca. Central small to
moderate in size, hexagonal, bordered by Pec 2-8. Pec 1 and 3
widely separated from central, small. No accessories present. Pec
2 and 4 in contact with laterals (LL 3, 4, and 6). Facetals paired,
together occupy about 60 per cent of tegminal surface. All plates
smooth or slightly granular, tumid. Gonopore and hydropore not
seen.

PERIPROCT: Circular, protrusive, bordered by Pec 6-8 and LL 7
and 8, diameter 0.68 mm.

Remarks. —Miller (1892, pp. 630-631) originally erected the
family Stribalocystitidae and the genus Stribalocystites to receive
one species, S. tumidus, described from a single specimen. The
distinguishing characteristics of the family are stated to be the
tumid plates and the fact that it has "no arms." I have been un-
able to locate the holotype of this species, but from the description
and illustration it appears to be a juvenile. A number of small,
immature forms have subsequently been collected but juveniles of at
least both the preceding and following species would be indis-
tinguishable from "S. tumidus'''' since all St. Paul cystoids in this
range are poorly preserved. At any rate, very young examples of
any caryocrinitid species cannot be readily discriminated from
juveniles of other species under the best of circumstances.

In 1894 Miller added a second species, S. gorbyi, to the genus,
described from two better-preserved specimens. This form may
well be conspecific with S. sphaeroidalis, judging from the figures
and written description, but the types, formerly in the Indiana State
Museum, appear to have been lost. The holotype of S. sphaeroid-
alis (Miller and Gurley, 1895), while crushed and apparently etched
by treatment with acid, shows a tegminal plate arrangement
identical to that seen in numerous examples of ' 'S. gorbyi ' ' collected
and subsequently labelled by Miller, Gurley and others.

Stribalocystites tumidus, even if the type is later located, is, in
my opinion, a juvenile of an undeterminable species; accordingly
the name should be restricted to the type. The specific name
sphaeroidalis thus applies to the only available recognizable entity,
despite the imperfection of the holotype specimen, until and unless
the types of gorbyi are relocated. The characters of "Stribalocys-

FREST: CARYOCRINITIDAE 97

tites" sphaeroidalis, as outlined above, do not seem to be suffici-
ently distinctive from Caryocrinites to warrant the recognition of a
separate genus. The genus is, therefore, placed in synonomy with
Caryocrinites, following Bassler and Moodey (1943, p. 137).

This species is by far the most abundant cystoid in the Laurel.
Judging by lithology, most of the old specimens were collected from
the shaly beds at the top of unit 4. Most of the specimens I collect-
ed were from the middle of unit 3. Those from the more calcareous
sediments are consistently better preserved.

Caryocrinites shemai new species. Figures 10g-l, 11.

Diagnosis. —A small caryocrinitid with six brachiole facets and
thin, highly convex plates. The tegmen is moderate in size, Pec 6
and 7 are fused, and only Pc 1 is not in contact with the palatal.

Type. -FMNH PE 19173 (holotype).

Material. —One damaged theca, FMNH.

Horizon and locality. —The holotype was collected in unit 2 of the
Laurel, 4 in. above the base in the Adams Quarry, south of St. Paul,
Indiana.

Description. —

THECA: The holotype is a small, inverted pyriform theca with a
gently convex oral surface, height 12.6 mm. and diameter 9.56 mm.

PRIMARIES: BB average in size, BB 1 and 4 considerably larger
than 2 and 3 (height 3.83 mm., width 5.01 mm., H/W ratio 0.77),
hexagonal. BB 2 and 3 small, broad, pentagonal with a H/W ratio
0.97 (height 3.81 mm., width 3.94 mm.). All BB convex, ornament-
ed with one or two major ridges and several minor ridges coalescing
at base of each B.

Shapes of DLL and LL typical for genus (fig. 2). ILL 1 and 6 and
LL 1 and 8 damaged on specimen. Dimensions of BL 5: height 5.20
mm., width 4.02 mm., H/W ratio 1.26. Corresponding dimensions
of IL 2 and 3: 5.41 mm., 5.21 mm., 1.04 and 5.48 mm., 4.84, 1.13,
respectively. Height and width of visible portions of LL about equal
to that of BB.

All plates thin, highly convex, ornamented with low, crooked
ridges radiating from the center to the corners of the plate, as well
as many irregular short ridges and knobs. Cryptorhombs on L-IL
sutures with nine or 11 dichopores; those on B-BJ with five dicho-
pores. Intra-circlet cryptorhombs consist of single dichopore across
IL sutures. Pores on BJL simple, those on BB and LL complex.

TEGMEN: Central large, heptagonal, adjoined by Pec 2-8 and one
accessory. Pec 6 and 7 fused into single plate, Pc 1 separated from

FlG. 10. Caryocrinites sphaeroidalis (Miller and Gurley); a-d, f, paratype
FMNH PE 19175a; e, paratype FMNH PE 19175b. a, anterior lateral view; b,
posterior lateral view to show protrusive periproct; c, left lateral view; d, right
lateral view to show tumid plates; e, oral view to show ambulacral facets and teg-
men; f, basal view. g-1. Caryocrinites shemai n. sp. (holotype FMNH PE 19173).
g, anterior lateral view to show compound pores on LL; h, posterior lateral view to
show periproct; i, left lateral view; j, right lateral view to show ambulacral facets
and plate ornament; k, oral view to show tegmen; 1, basal view. All X 1.5,
whitened with ammonium chloride sublimate.

98

FREST: CARYOCRINITIDAE 99

Fig. 11. Diagrammatic representation of tegminal plate arrangement in Caryo-
crinites shemai n. sp. A-anus; C-central; Pec numbered; ambulacral facets dotted.
Dotted lines indicate plates damaged in holotype.

central by 2 and 8. Accessories include paired large plates associ-
ated with each ambulacrum and considerably smaller plates occupy-
ing positions between ambulacral branches. Peripheral region of
ambulacrum I damaged. Tegmen diameter five-sixths that of theca
at widest point. Brachiole facets 6, in groups of two separated by
Pec 2 and 4 and plates surrounding periproct, developed on pairs of
facetals. Openings for sensory brachioles present, disposed as in
C. laurelensis. All tegminals highly convex, with strongly elevated
central node. Gonopore and hydropore unknown.

PERIPROCT: Bordered by Pec 6-8 and LL 7 and 8, elliptical in
shape, 0.90 mm. by 1.38 mm. in diameter. Surrounding plates
flush with rest of theca.

Remarks. —Even though the single known specimen is incom-
plete, the holotype presents a combination of distinct features
which warrant its recognition as a separate species. Because of the
rarity and restricted occurence of C. shemai, it seems unlikely that
any other specimens will be found in the near future. The specific
name honors the finder, Mr. Joseph P. Shema.

Caryocrinites stellatus new species. Figures 12, 13.

Diagnosis. —A small spheroidal species having a tegmen no more
than one-third the maximum diameter of the theca and strong
stellate ornament. The central is bordered by seven plates (Pec
1.5, 7, and 8).

Material. —At least 14 complete thecae. FMNH.

Horizon and locality. —Specimens I collected came from the lower
6 in. of unit 2 and the upper half of unit 3, Adams Quarry. Most

Fig. 12. Caryocrinites stellatus n. sp. a-e, holotype (FMNH PE 19174a); f,
paratype (FMNH PE 19174b). a, posterior lateral view to show periproct; b,
anterior lateral view; c, left lateral view to show irregularly developed dichopores;
d, right lateral view; e, basal view; f, oral view to show tegmen. All figures
whitened with ammonium chloride sublimate, X 1.5.

a

Fig. 13. Diagrammatic representation of the tegmen of Caryocrinites stellatus
n. sp., based on paratype FMNH PE 19174b. a, oral view to show relative di-
ameter of tegmen and theca; b, enlarged representation of tegmen. A-anus;
C-central; Pec numbered; ambulacral facets dotted.

100

FREST: CARYOCRINITIDAE 101

museum specimens probably were from the uppermost 1.5 ft of
unit 4 at the same locality.

Description. —

THECA: Subspheroidal, small (height 10.00 mm., H/W ratio
1.05). Primaries thick, tumid, with impressed sutures, surface
broken by short, broad ridges arranged in stellate pattern originat-
ing from corners toward center of plate, not meeting. Small sub-
central tubercle often present, rest of plate including ridges
smooth.

PRIMARIES: BB broad, forming low saucer-like cup, deeply exca-
vated for insertion of small (diameter 1.29 mm. in holotype),
rounded column. BB equal in height, but BB 2 and 3 narrow,
pentagonal (H/W ratio 1.24), while BB 1 and 4 broad, hexagonal
(H/W ratio 0.90).

ILL 1 and 5 narrow, pentagonal, H/W ratio 1.16. ILL 2 and 4
larger than other ILL, broadly heptagonal. ILL 3 and 6 hexagonal,
more than usually narrow, H/W ratio 1.28. LL medium-sized,
nearly equal in area. All plated broadly curved along long axis,
strongly convex.

Cryptorhombs not clearly defined, apparently irregularly sub-
rhombic with 5-11 dichopores in L-LL rhombs, 3-5 in B-IL rhombs.

TEGMEN: Entire oral surface weakly convex, tegmen occupying a
relatively small area (diameter about 3 mm.), distinctly triangular
in shape. Brachiole facets three, large. Opening for sensory
brachiole developed on right side (proceeding in a clockwise direc-
tion from periproct) of each pair of facetals. Central surrounded by
seven Pec, no accessories present. Pec 6 and 7 small, 6 not in
contact with central. Remaining pericentrals about equal in size,
thin, not tumid, smooth.

PERIPROCT: Small, circular, protrusive, set high on theca. Peri-
proct bordered by Pec 6-8 and LL 7 and 8, diameter 0.96 mm.

Remarks. —Though uncommon, this species is the third most
abundant at St. Paul. Specimens I personally collected were from
the more argillaceous portions of the formation, particularly the
upper 12 in. of unit 3. A dolomitized partial theca referable to this
species is registered in Field Museum (PE 24282). According to the
label, the specimen is from the Joliet Dolomite, Chicago Drainage
Canal, Lemont, 111.

Caryocrinites tribrachiatus new species. Figures 14a-e, 15.
Diagnosis. —A medium-sized caryocrinitid characterized by its

102

FREST: CARYOCRINITIDAE 103

elongate theca and wide tegmen with three exceptionally large
brachiole facets.

Type. -FMNH UC 33678 (two specimens: holotype UC 33678a,
paratype UC 33678b).

Material. —Two complete thecae, two partial. FMNH.

Horizon and locality. —Fragmentary specimens collected by the
author came from the upper third of unit 2 at the Adams Quarry.

Fig. 15. Diagrammatic representation of tegminal plate arrangement in the
holotype of Caryocrinites tribrachiatus n. sp. Pec numbered; A-anus; C-central.

Description. —

THECA: Elongate, subturbinate, stem facet small. Dimensions of
holotype: height 36.5 mm., diameter 14.1 mm., H/D ratio 2.59.

PRIMARIES: Ornamentation consists of radial ridges to corners of
plates and extensively developed secondary ridges and chevron-
shaped nodes. Cryptorhombs with 15-17 dichopores in IL-L
rhombs, nine dichopores in IL-B rhombs, and three in IL-IL
rhombs.

All BB higher than wide (BB 1 and 4 H/W ratio 1.03, BB 2 and 3
H/W ratio 1.31), facet for column attachment slightly indented into
BB, round, diameter 3.80 mm. ILL with shapes typical for genus,
elongate (IL 1: H/W ratio 1.26, IL 2: H/W ratio 1.19, IL 3: H/W
ratio 1.31), approximately equal in area.

Opposite.

Fig. 14. a-e, Caryocrinites tribrachiatus n. sp. a-d, holotype FMNH UC 33678a;
e, paratype FMNH UC 33678b. f, Caryocrinites sp. (FMNH PE 27826). a,
anterior lateral view; b, left lateral view; c, posterior lateral view to show periproct
and ambulacral facets; d, oral view to show tegmen and ambulacral facets; e,
lateral view of paratype to show plate ornament and cryptorhombs; f, lateral view
of preserved plates of Caryocrinites sp.

104 FIELDIANA: GEOLOGY, VOLUME 30

All primaries gently convex, thin, sutures not deeply impressed.

TEGMEN: Trigonally symmetrical, large, elevated somewhat
above the level of the LL. Brachiole facets three, exceptionally
large, developed on paired facetals, broadly smooth. Central small,
in contact with Pec 2, 4-8, Pec 1 and 3 small, widely separated from
central. Sensory brachiole pores developed on sutures between
pairs of accessory plates, upper of which is quadrangular and about
one-third maximum length of lower pentagonal member of each
pair. Two such pores are associated with each brachiole facet.
Gonopore and hydropore not observed.

PERIPROCT: Small, rounded, about 2 mm. in diameter, oriented
parallel to main axis of theca, nearly at a right angle to rest of
tegmen. Periproct bordered by Pec 6-8, LL 7 and 8.

Remarks. —Although this species somewhat resembles the
Waldron Shale species, C. persculptus, in size and shape of theca
and plate proportions, the features of the tegmen are completely
distinctive. It is unusual in possessing only three brachioles despite
having a sizeable tegmen. The arrangement of the TT in C. tri-
brachiatus closely resembles that in C. sphaeroidalis, from which it
differs in the size and shape of the theca, the area of the tegmen,
and in the relative sizes of each plate circlet. C. tribrachiatus also
lacks the thick tumid plates of the latter species.

Caryocrinites sp. Figure 14f.

A small weathered fragment of a large caryocrinitid was discov-
ered loose in weathered material at the Adams Quarry locality.
Associated fossils suggest that this material was derived mainly
from unit 2. The incomplete nature of the specimen precludes
accurate determination at the specific level, but the proportions of
those plates preserved are considerably different from those of C.
laurelensis, the only other Laurel species which attains a compar-
able size. The inferred shape and size of the original fossil are
similar to those of only one other described species, the common
Brownsport (Ludlow) form C. romeri Jaeke.

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