~ = Si me ct ceebe : ss HARVARD UNIVERSITY e Library of the Museum of Comparative Zoology Pa. o Cah ne fa pen! A ., ‘7 coal NPBA Sa felons iP sree hing na eh (len on fithrethuls Vortiwakha * a Se tane-e aquired Veen endl oa b, P, .eb ard) fist Ma qbeh * ae. Tio Le ao ariqy > - Goes Te, ‘et ce ee i a a Begun in 1895 VOLUME 112, NUMBER 353 FEBRUARY 17, 1998 Systematic Paleontology, Biostratigraphy, and Paleoecology of Middle Ordovician Bryozoa (Trepostomata) from the Hermitage Formation of East-Central Tennessee by Edward Joseph Marintsch Paleontological Research Institution 1259 Trumansburg Road Ithaca, New York, 14850 U.S.A. PALEONTOLOGICAL RESEARCH INSTITUTION Officers IPRESTIDEN iy eae cr te ene eee TS Re oer aT eee eee CONSTANCE M. SOJA FIRS VICES RRESIDENT ioe eer eateries iaanre ote sieieieiees DONALD L. WOLBERG SECONDS VICE-PRESIDENT 6) sie tee Gee hee nie ee SHIRLEY K. EGAN SEGREDAR WA Wap Wee iuntne oa geen cetyl nisi eae rarete see as ta) Sa nie HENRY W. THEISEN SEREASWRER Me teh eet once icmer ie re Chern eee CEN ave esteem aca HOWARD P. HARTNETT DIRECTOR WE Re tee ee ee eae oh Pe eereh Ter eee WARREN D. ALLMON Trustees CARLTON E. BRETT (to 6/30/98) MEGAN D. SHAy (to 6/30/99) WILLIAM L. CREPET (to 6/30/00) CONSTANCE M. SojJA (to 6/30/97) J. THOMAS DuTRO, JR. (to 6/30/99) JOHN C. STEINMETZ (to 6/30/97) SHIRLEY K. EGAN (to 6/30/98) PETER B. STIFEL (to 6/30/00) M. G. HARASEWYCH (to 6/30/98) HENRY W. THEISEN (to 6/30/98) HOWARD P. HARTNETT (to 6/30/99) Mary KANE TROCHIM (to 6/30/98) Harry G. LEE (to 6/30/00) GREGORY P. WAHLMAN (to 6/30/99) Amy R. McCCUuNE (to 6/30/00) THOMAS C. WHITELEY (to 6/30/00) SAMUEL T. PEES (to 6/30/98) DONALD L. WOLBERG (to 6/30/99) EDWARD B. PIicou (to 6/30/98) Trustees Emeritus HARRY A. LEFFINGWELL ROBERT M. LINSLEY JAMES E. SORAUF RAYMOND VAN HOUTTE WILLIAM P. S. VENTRESS BULLETINS OF AMERICAN PALEONTOLOGY and PALAEONTOGRAPHICA AMERICANA WEARRENSID SA TAENION] aces seoesiapes cates mae ee th Ou clare oo tea CaSO SERVE OU eR EDITOR Reviewers for this issue Marcus M. Key, Jr. EDWARD M. SNYDER A list of titles in both series, and available numbers and volumes may be had on request. Volumes 1—23 of Bulletins of American Paleontology are available from Periodicals Service Company, 11 Main St., Germantown, New York 12526 USA. Volume | of Palaeontographica Americana has been reprinted by Johnson Reprint Corporation, 111 Fifth Ave., New York, NY 10003 USA. Subscriptions to Bulletins of American Paleontology may be started at any time, by volume or year. Current price is US $67.50 per volume. Numbers. of Palaeontographica Americana are priced individually, and are invoiced separately on request. for additional information, write or call: Paleontological Research Institution 1259 Trumansburg Road Ithaca, NY 14850 USA (607) 273-6623 FAX (607) 273-6620 © This paper meets the requirements of ANSI/NISO Z39.48-1992 (Permanence of Paper). Begun in 1895 VOLUME 112, NUMBER 353 FEBRUARY 17, 1998 Systematic Paleontology, Biostratigraphy, and Paleoecology of Middle Ordovician Bryozoa (Trepostomata) from the Hermitage Formation of East-Central Tennessee by Edward Joseph Marintsch Paleontological Research Institution 1259 Trumansburg Road Ithaca, New York, 14850 U.S.A. ISSN 0007-5779 ISBN 0-87710-444-1 Library of Congress Catalog Card Number: 97-75709 This publication is supported in part by a Corporate Membership from Exxon Exploration Company Printed in the United States of America Allen Press, Inc. Lawrence, KS 66044 U.S.A. CONTENTS Page (AGS) oan od augacneeaded oat oo dane mondaonGomaayn Good dons OhE CObeT ON oGn DG OUU OOOO Se OOD OMoDs A oe Be OOD 5) RC EEON os 4 sas cae Sn OOOO ED DOsmAOE oO eMOmO GO Cob onoOonuCGSUGonO tO OOS UUabodDO no Medd os On aot ae ta oon 5 INAREWIEIETING sco pcogaaeae dee enabopGaueNe booed ono Oso eS oe DON CdOAHOOOdOUsODUDOUCOO DS OooURODUOUNO 6 Materials and Study Techniques CONIA LOANS scacscsooaosanoddaonaeo FG FMHohe adh Suse ues obsosondobooHuLUDEdoDETHoDoNSoODSbObOD 7 SEN LAR ranean antel Sanehy IMINO op oo cae ooo Soo E NCO bOb EoD SUS Oooo OoODFOODOCOe CoO HCASG on aC da bedGuoOOS 7 APATHY OF SRASMIEIS soc oo oao eee ne doen e oor on GoD ORO R CODE DOU SH EUeD UF OboO DUOC ECON DE SOHUOOUO OOM CONES 8 StranprinnreCollectonmeevels;and: specimen Identiti cation Gabelsy sage: arene) ition eee) eledone erate) ededicmees) ele release =e ener 8 The Hermitage Formation (Genaq! Pisminion ara! SUUGIMISOMS ocooscesoco pub D Rr ODE ODD CO UOt DOO CUO SOO OD UnODOC HOO atH EDUC HOH COONS HO 9 jS(Sar ASS Gi he NG) AWE oo ooo donpend note dor oon et OD does Gon SOMedODS OHH GODS doe SC HOdOH SOHN OOOO OEE OC 10 QisiGrnnine RESON acoaoneenbebacorgg so GoD Nsw OO OD IDO DD OOUd ab OSU ODO UEC DH AnRdoOUUCo DOSS OKC COSaGoBS 11 General Depositional Settings of the Hermitage Formation and Stratigraphically Contiguous Strata ..............---...2---. 11 Trepostome Bryozoan Faunal Analysis Trepostome Bryozoan Assemblages from the Hermitage Formation of the Eastern Tennessee Study Area ...........---...--- 13 inGyeamn AMET GS ONS so adacnbopoeoocoDNODaneu done te DUD Do HODDbODHONConUOSoonDiNEecoDAd ene oon aA 13 SIV COR AGT EEO ING scboootnoonPbaD OO ao OmNOD OH dOoHGOb COD DONE SODUCONdObUHOoO BOD Medco oabe te NOS 13 BiH GAGE ACETATES WES go oon booue nd oon OSM OO ONC OOD ODM aD DOOD ooo UOMO NOG Oogcon Sonne D eco aD 13 Comparison With Some Other Middle Ordovician Bryozoan Assemblages ........... 02.0.0 see eee eee eee eee ee eee 15 Biostratigraphic Utility of Bryozoan Distributions from Tennessee Study Area ..........-- 0.00. e ee eee ee eee eee eee eee 24 COnclOSionS peer NM Tee re ee ee ae ite gai ecoret cepted sae tell tyelinierromemebenedtens (steht see! Cuenerions) etetopaucus apere cen eee) ect Se Menatenearal 28 Introduction to Systematic Paleontology TAOS (COyNSCERTONS 3.6 5.6 coe aoc 6.0 WOO eIAIe mien oh clomn Poeun b H6.6 Go Gm Ore Oi 6 O10 CIO OS Cito 6 Didia coin o.oo A onc 29 GlossaryiofalemussUsedine Morphol osicsDescriptonsyejery- teres) rotenone Nats ote ele ee tela te lcedelre feliedied eae etlententell =e teel =A -rt-e=it- f=te-Te= 30 IDG IG NIEHS 650 oc Ohbos on ODOC eM OUmato Dee SOR moe bon nao mooodoowUoKao mE cobb can Obo.C 32 Key ora bbreviationsiUsedmnmlables of Onantitative sD atagen erst pene takes ae eatele) ete sited eli Mealtel eee eel ieee t= ell i-th -tIE ania 33 Systematic Paleontology GeniseErasoporaeNicholsonsang Ether Pee. ete ierete erecta ee Pa coenel) Asse d eset leas enoue ciate eliclis: cPelsiten chee cckeyietcite slit -b-aen=P gers 33 (Gens) Goa inyae. WIEN 6 5 olesaiotg claro ole olclol OID aoe Ololcieinnctn cick e comin int crc In Soliris Soh oie or nis mini inec ome otchoccacsora ici) 35 Genus Pero7opormiNicnolsony seats seis ei spate eis se, spe sieper eas ene eaue eben etou else: alist ca) cree) ei'e) oie) (oleae batede:le pelreglopelt=h a= poyceeveh atfetans 39 GenusiAcantholaminalspuy ene say) oe) = =e a seleiere sel soe) el csi) alle) a= nts asieire a) al nde api ch evvorel al eliette) ecto) eliaw=atien@ Wee Neen Ves heath 42 Gaus leeiiain~ee Wat sosupogowos hoo mesuboUunoGUTOmaC OD GORE OO HUA COMO Oe ODEO On Golo oom aoRS ate RG 44 Genus Monniculiporardi@rbipny! nia 3-75 ois cist see ote sno) ies oe ee ae mh oe ae cite abies allay 0) stisio ole) ote as ahve lieu ete orcad age) eVC= eases =i 56 Semi Si caone IWS? AID Se noes mocnoadgeoo poop oD DOopob oD Soo noma ee OOn oO adobe ooo omOD Onno oD Soo 57 SEIS ITAA GANONG sels ob Soo SOOO OOOO 6 Oo COO S cee sino omer copiC rudy iD. whagd cus ein obewsi oc a.tho'G b.o.6 61 Genus PE ridonypapaCh ee reyeeie so cis ica ok we oe cie oir) of eutectic, ole sy spe ape Soebe w pelts eis euee, elses ical fetiel el elietisiler nice fo¥ies =itsital =) trader si feite 64 (Sani Fa Dinyze NANI os ssa0unondoueoubOObou Su coaa gor doom MoO GoM GoD m mo Ea OoOR SOOO MOO Coda oo OM 67 Grails Cyylvaiayar: Wine curl BECHEP ob ooonon nob ubon ob onooune dose Hoo ne DOOUMmMONn DC Odom oo om DoD mS Vl (SareQiyaqie wingn cil BEC! - 46 om bon somo dp do So clon mone ome 6 9 SOiBacrcecis Osis che o canted lice bhorosenieinl clo Alc alc 77 (Gene ag dal nee VST. oe poole bon dodo OO 0 OOS Die Oat moe oom Cin Onan DadnmcMo poe rane soo ols 5 79 Seis len Vel Piel! St ont oon eos HOKE MeO ODOM EU DOs Coo mmo Ooo. BODIES Or lo Da eh dd on Ao Or oo tc ood 82 (Cenc ease lala! ERS EES ¢ 6a ele Golo b Gite o GIG OGIEIOD Cio picid GisEs Groin igiolonic. ice orolracs 6. o tio cbr mio air ar crcita ois Bigns 87 (CokveC rd agi WUE 6 oo coon mound 260 Galea Golan ccmdion Umea co camino, cicminitne Mit Sco op.clon poe dd Go ane 6.016 6 89 [Sierra (ONS! ee ck k oo tne Hoa OC OOS Une PU CO HOD EO OCR oD Om ern Acar eto c Tate ohn oO cibm non mnie cn Oc citar Dd 1 90 EATS Brera 3 cP ne eee TEN en cre Teac eer ce toue Ge ehcr ela cays ne CS cils-cie sn ic uletis cocettelial cjidise, oust lice reeds (are/Mellobe nse) aestage) eee in) euelsetaltatten eve dati 93 LTE Eno Ble oc by Cs 9 Chen Gcicn oD: CAC Bor tl EPCe eo le oar FONG Ono ir Sire EEA rec er Oech oie panier Care back coINicnti mn OiGin Die a son cmioWea pio)o 118 LIST OF ILLUSTRATIONS Text-figures Page 1. Map showing study area in eastern Tennessee ......----- eee eee eee et tt ett ee tee ete eee teens 10 2. Graphic display illustrating relative abundances of common trepostome species (= 3%) within Bryozoan Assemblages found at Norris (oa DNRC Os me's o nie RO ED IO BG be De Cine CRORE OTRAS RmmTRS ky & oiola cori oiG ockuloiame oldimeyoraks cic 15 3. Graphic display illustrating relative abundances of common trepostome species (= 3%) within Bryozoan Assemblages found at (live ta iT STA ea ein tae Bay Bi Gio d Cle bid oC OIC ERE PIO CE © CaPemipie tien 3 CaO OiaE clot O Old Cito Cecio ol Geatnc gory Seamiae 17 4. Graphic display illustrating relative abundances of common trepostome species (= 3%) within Bryozoan Assemblages found at WUAIEESTIP ES LITICHISECTAOL Tae eoeneis cette ee cte ai a ot ST aia a VaR See ay ais Ser aaneiiens, wicerers elcL cyt a ter Poke rere one Memelie citar ave Wate arse deteewtel ele ta 18 10. Graphic display illustrating relative abundances of common trepostome species (= 3%) within Bryozoan Assemblages found at HowardiGemeteryiSeCtlomin nc: senate eters N aera meee mee ereee eet eke ie asf Lat none ial al Chel stones Boh cgtonts ap eee ocean ee ea Wateralsrelationshipsiof Bry. ozoanvAssemblagesracrossstuidy ated eye i ey eelteealcnel iets teed =i et eiic ire diclies =) leit =u etnies eure nme tenants Range chart of trepostome bryozoan species found at Norris Lake IV section showing all horizons of occurrence as well as strati- graphic distributions of Bryozoan Assemblages and Biostratigraphic Units .............-. 0-02 eee eee eee eee eee Range chart of trepostome bryozoan species found at Chamberlain Branch section showing all horizons of occurrence as well as stratigraphic distributions of Bryozoan Assemblages and Biostratigraphic Units ................. 00000000 eee eee eaee Range chart of trepostome bryozoan species found at Wilson Branch section showing all horizons of occurrence as well as stratigraphic distributions7of BryozoanlvAssemblagesiand)iBiostratigraphicUmitsi ocean =e ieee i eiteiiel ca) ie) eee een Range chart of trepostome bryozoan species found at Howard Cemetery section showing all horizons of occurrence as well as stratigraphic distributions of Bryozoan Assemblages and Biostratigraphic Units .................. 2.2 eee ee eee ee eee LIST OF TABLES Table ile een anewn 21 NNne Pao) N Relative abundances of common trepostome species (= 3%) within Bryozoan Assemblages at Norris Lake IV section ......... Relative abundances of common trepostome species (= 3%) within Bryozoan Assemblages at Chamberlain Branch section ..... Relative abundances of common trepostome species (= 3%) within Bryozoan Assemblages at Wilson Branch section ......... Relative abundances of common trepostome species (= 3%) within Bryozoan Assemblages at Howard Cemetery section ...... Relative abundances of common trepostome species found within Bryozoan Assemblage One ..................0..0000- Relative abundances of common trepostome species found within Bryozoan Assemblage Two .................-..-2-05 Relative abundances of common trepostome species found within Bryozoan Assemblage Three .....................-5-. Summary of relationships of Bryozoan Assemblages to lithotype, associated macrofossils, and environments of deposition ..... Quantitative idatayPrasopora falesis(Vames) i freee ors © © cue cee ole = os) ch cre fo) oy Gite) oe erence eeu cme he IeMSiel sl otek ain ner nena Quantitative data Mesotrypa angularisi\(Wirichtand: Bassler)! << <<: nt 20s «) «fo eesnsiioy ciel =) ation stich eis) ute msl cect +t cle eee eee til ene ~ Quantitative data yMesotry pal sp cA ii .aeb ct Rusien ers es. = le) Syatien@ opis aiie Sciielle) one) ons Wee eepray op cblae- pole neeed cueetisatoues GUA) eens) eu sucisaeypeate rss Srna Quantitative datasPeronopaoralmundulas(WItich) rece cece ee ene ieeue el ecisin) hci slices lina eet ome ite see eee aan eee g.QuantitativerdatayReronaporalwelraems SPs. et) see ms cie) = eae eV) es ol hel = Pee MSI Reae ee ee eS Ve sient cr een eee ~~ @uantitativerdata A cantholaminatusity PICUS Ms) 2eM. sll iSPei eae (4 -u-y aii dee-as) eens newness ieee ceed oe tena an ee .OuantitativerdatayAcantnolaminalus» MmuliustylUsiMs LEM mMle SPs ec -ea-ae eens ecu aeeele ea ee a ee ene eee ee QuantitativeidatasHomotrypaiminnesotensisNWIniChite.. a7. oa =e) si ole eee eee een ere eit ne ae pa. Quantitative: datas Homotrypajlabellaris var. spinifera Bassler 24 /)cscierel eee 4 ete ete cle a) Gece eae cena eee QuantitativeidatawHomotyparsimilissHOOrd! \. 2). eres fie son @ 0) 9) afer) oer rect) ea aie) © enero ait) re) eee) enti Rene renin Quantitativeidatay HomotnypastabulatagmySps eects = apeite is 4 lepias ep 2) ais cis) sre deueproh sr cutenetous| sue Tarphophragma multitabulata; Bythopora dendrina > Batostomella subgracilis; Parvohallopora pul- chella + Parvohallopora granda) are rather subtle since the range in morphologies found within these species-couplets is often expressed as a largely continuous gradient in zoarial form between taxa. Groups of numerically dominant trepostome species were observed to occur in time and space and have been referred to herein as Bryozoan Assemblages (One, Two, and Three). Assemblages are generally correlated with subtle changes in lithotype (= lithofacies) ranging from muddy and argillaceous wackestones to clean packstones. When compared with other Middle Ordovician bryozoan faunas, taxa from the Hermitage appear to be most similar in species composition to part of Karklins’ (1984) Tarphophragma multitabulata Assemblage Zone of Kirkfieldian to lower Shermanian age. Three loosely defined local biostratigraphic zones (five zones within the eastern sections) are present within the Hermitage of the study area and have boundaries which are possibly influenced by variations of local lithofacies. INTRODUCTION John Rodgers (1953, p. 64) stated that “‘probably more controversy has raged over the stratigraphy of the Chickamauga limestone and equivalent rocks in the southern Appalachians than over that of any other major unit here discussed except the Ocowee Series, and this despite the generally good outcrops, the ready accessibility of the outcrop area, the well char- acterized and differentiated lithologic units, the sev- eral usable key beds, and the abundant fossils. The controversy has concerned both subdivisions and cor- relation.”’ Over thirty years later, much of what he said is still true. Time-equivalence of strata when at- tempted is based mainly on presumed lateral litho- facies relationships with a minimum of biostrati- graphic control (Walker ef al., 1983; Ruppel and Walker, 1977; Walker, 1974; Walker and Alberstadt, 1976; Wilson, 1949). The problem of correlation is further complicated by the fact that exposures occur along strike belts that are sometimes widely separated because of folding and thrusting. It is apparent that in order to reconstruct geologic and evolutionary events that took place in the southern Appalachians 6 BULLETIN 353 during the early Paleozoic, a detailed, workable bio- stratigraphic zonation is needed. The research presented herein is principally a bio- stratigraphic study carried out within the Hermitage Formation as exposed in the Valley and Ridge Prov- ince and Appalachian Plateau of East-Central Tennes- see. Efforts have been specifically directed toward the systematic paleontology of the trepostomatous bryo- zoans. Bryozoans have biostratigraphic potential and are numerically dominant, geographically widespread, and taxonomically diverse, but are virtually ignored within strata of the Southern Appalachian Basin. In- deed, Walker and Ferrigno (1973, p. 301) in a study of Middle Ordovician reefs in East Tennessee stated their opinion “that the abundance, wide occurrence, and rapid evolution of the ectoprocts of the Middle Ordovician require their careful testing as biostrati- graphic indicators.”’ The bryozoans, then, would seem to be a potential tool in the understanding of facies changes and other lateral relationships at this place and time. An initial advantage in carrying out this partic- ular study has been the presence of a distinctive lith- ologic unit traceable throughout the study area, name- ly, the T-3 Bentonite which occurs at the base of the Upper Carters Limestone (see Kolata er al., 1987, and Samson et al., 1987, for chemical correlations of the T-3 Bentonite with K-bentonites of the Upper Missis- sippi Valley). Since bentonites are generally believed to be deposited isochronously, the study of fossilifer- ous strata above the T-3 horizon allows us to gain an increased perspective of the spatial and temporal vari- ations of a faunal group within approximately time- equivalent strata. At the time that McKinney (1971a) completed his work on the Middle Ordovician trepostomatous Bryo- zoa from Alabama, he remarked that only one study of Middle Ordovician bryozoans south of Kentucky had been published (although he notes a number of “incidental reports’ found in several stratigraphic works), that of Coryell (1921) on the ectoprocts of the Stones River Group of Central Tennessee. (Presently, the Stones River Group is thought to encompass that part of the Chickamauga limestone up to and including the Carters Limestone.) McKinney limited his work to the lower Chickamauga Group up to the T-3 Bentonite in northeast Alabama. Within Central Tennessee, the only contributions to the paleontology of the Hermit- age Formation are those of Bassler (1932) and Wilson (1949) who merely list species of Bryozoa from the Central Basin. Techniques accessible and knowledge available at the time of their publications concerning the bryozoans were rather poor (compare, for example, the 1953 Treatise volume with the latest (1983) edition published by Boardman et al.); furthermore, many spe- cies in the past were defined typologically, largely ig- noring the effects of genetic and ecophenotypic vari- ability among population members. The present report, then, is the first major paleon- tological study of bryozoans from Ordovician strata above the T-3 Bentonite within the Appalachians south of Kentucky. Only a few other studies provide detailed information on the presence and distribution of Or- dovician trepostome species from areas in relatively close geographic proximity to the Hermitage of Ten- nessee. McKinney (1971a,b) studied the trepostomes (24 species) within environmentally undifferentiated biomicrudites, micrites, and calcareous shales from the Lower Chickamauga Group of northeastern Alabama. The upper stratigraphic limit of his study is marked by the T-3 Bentonite. His lowermost strata are equivalent to beds not older than the Ridley Formation. Within the present study area the T-3 Bentonite is separated from the Hermitage by the Upper Carters Formation, approximately 35 feet (10.7 m) of fossil-poor strata. Karklins’ (1984) detailed work describing 22 species of trepostomes from predominantly platform carbon- ates of the Middle Ordovician Lexington Limestone and Upper Ordovician Clays Ferry Formation in north- ern Kentucky and Brown’s (1965) work in the lower Lexington Limestone of central Kentucky are, in part, laterally equivalent to the Hermitage (environments of the various Lexington Limestone Members are de- scribed in Cressman, 1973). Singh (1979) identified 16 trepostome species mainly within ‘“‘organoclastic”’ limestones of the Upper Ordovician Bellevue Lime- stone of Kentucky, Indiana, and Ohio which is sepa- rated from the Clays Ferry by the Fairview Formation. Though the integration of bryozoan species distri- butions from varied published geographic and strati- graphic works is beyond the scope of the present re- port, the trepostome systematics and distributional data presented herein should permit a better understanding of trepostome bryozoan evolution as well as the larger- scale biostratigraphic and paleogeographic relation- ships within and among various southern Appalachian Middle Ordovician environments. Any attempt to un- ravel such phylogenetic and paleoecological distribu- tions must begin with a detailed and thorough exam- ination of the component fauna. The study and includ- ed data base presented herein, then, is a first step and major building block in the understanding of these re- lationships within a heretofore largely unstudied, yet fossil-rich, geographic area. ACKNOWLEDGMENTS The writer acknowledges the help of Dr. Peter W. Bretsky of the SUNY at Stony Brook, my dissertation advisor who proposed this research topic, provided en- MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH 7 couragement throughout, and was always available for discussion. Dr. Richard S. Boardman of the Depart- ment of Paleobiology, Smithsonian Institution (pres- ently Curator Emeritus) provided supervision during my tenure as Smithsonian Pre-Doctoral Fellow at the National Museum of Natural History in Washington, D.C. Dr. Roger J. Cuffey of the Pennsylvania State University and Dr. Olgerts L. Karklins of the United States Geological Survey (presently retired) freely dis- cussed various topics related to this author’s work and offered insightful and uplifting comments. Dr. Robert C. Milici, formerly of the Tennessee Division of Ge- ology, presently State Geologist of Virginia, graciously provided locality data for several outcrops in Tennes- see and took the author to several excellent localities. Dr. Frank K. McKinney of Appalachian State Univer- sity was kind enough to afford insights into his re- search with trepostomes as well as locality information and section descriptions of outcrops in northeastern Alabama. Mr. and Mrs. Ken Cooper of Kingston, Ten- nessee provided genuine southern hospitality while working at the Chamberlain Branch section near their home. Don Dean of the Department of Paleobiology, Smithsonian Institution freely gave of his knowledge into the preparation of trepostome specimens. The Na- tional Science Foundation (NSF Grant #EAR 7809952) and Sigma Xi insightfully provided grant monies in support of this work. The Smithsonian al- lowed me to study at the National Museum of Natural History in Washington, D.C. for six months. Dr. Mar- cus M. Key, Jr. of Dickinson College, Dr. Edward M. Snyder of Shepherd College, and Drs. Peter R. Hoover and Warren D. Allmon, past and present directors, re- spectively, of the Paleontological Research Institution reviewed this manuscript and offered numerous sug- gestions for its improvement. Dr. Key, in particular, left not a zoarium unturned in his most thorough scru- tiny. Mr. Neil Hanson and Mr. Howard Kiatta of Hous- ton, Texas provided financial support toward the pub- lication of this manuscript. Finally, but foremost, I am grateful to my wife, Fran, who has always been a source of encouragement. MATERIALS AND STUDY TECHNIQUES COLLECTING LOCALITIES 1. NORRIS LAKE IV SECTION. 36° 14’ 51” N, 83° 58’ 10” W, Big Ridge Park Quadrangle, Union County, Tennessee. This section is found on the northeast side of the fourth peninsula east of the Andersonville dock. Cart- ers, Hermitage and Cannon Formations present. Out- crop locality from R. C. Milici (pers. comm.). 2. CHAMBERLAIN BRANCH SECTION. 35° 49’ 13” N, 84° 31’ 06" W, Bacan Gap Quadrangle, Roane County, Tennessee. This section outcrops on the southwest side of the Tennessee River, directly southwest of the southeastern end of Long Island. The Chamberlain Branch flows northeastward into a small embayment of the Tennes- see River found south of the outcrop. Carters, Her- mitage, and Cannon Formations present. Outcrop lo- cality from R. C. Milici (pers. comm.). 3. HOWARD CEMETERY SECTION, 35° 29’ 08” N, 85° 15’ 45” W, Mount Airy Quadrangle, Bledsoe County, Tennessee. This section is found in Sequatchie Valley, east of East Valley Road, approximately 700 feet (213.4 m) northeast of Howard Cemetery. Outcrop was measured northeast of the branch flowing into the Sequatchie River. Entire section is exposed up the hillside. See also description found in Milici (1970). Carters, Her- mitage, Cannon, and Catheys Formations present. 4. WILSON BRANCH SECTION. 35° 46’ 23” N, 85° 00’ 45” W, Vandever Quadrangle, Cumberland County, Tennessee. This section is found in Sequatchie Valley three miles northeast of the intersection of East Valley Road and the road to Lowe Gap (on Melvine Quadrangle). Outcrop is on the east side and at the very end of East Valley Road near the intersection of the road leading west to the Alvin C. York highway. (Wilson Branch was not found approximately 500 feet [152.4 m] south of the road leading to the Alvin C. York highway as indicated on the 1956 Vandever, Tennessee Quadran- gle, but was found directly north of it). Hermitage and lower Cannon Formations are present. Outcrop locality from R. C. Milici (pers. comm.). SAMPLE PREPARATION AND STUDY METHODS At each locality, hand-sized samples were collected from each fossiliferous horizon. Where fossils were apparently absent or sparse, or where the unit was ex- ceedingly fossiliferous, samples were collected at ap- proximately 0.5 meter intervals. At each horizon, spec- imens of all the macroinvertebrate fauna were taken from different areas along individual bedding planes. At the same time, detailed field notes were taken of lithological variation, sedimentary structures, and bed- ding features. Sections were measured beginning at the chert bed found directly beneath the T-3 (or T-4) Bentonite. Samples were returned to the lab and cut into 2 cm thick slabs using a standard diamond blade. Slabs were then ground flat on a glass plate using 220, 600, and 800 silicon carbide grit in that order. Frequent crum- bling of friable slabs during both the cutting and grind- 8 BULLETIN 353 ing procedure was dealt with by impregnating the sam- ple with epoxy, Duco cement, or a clear acrylic lac- quer and then placing a thick rubber band around the periphery. After the final grit, slabs were highly pol- ished on an 8-inch diameter lap using 0.3 micron alu- minum oxide powder on a Buehler felt polishing cloth. Each slab was then etched for 3 to 4 seconds in a solution of 1:60 formic acid. Acetate peel replicas were prepared using 0.005 or 1.5 mm thick cellulose acetate sheeting. The peels were examined for litho- logic content, and the positions of nearly 5,500 tre- postome bryozoan specimens were noted on drawings of each polished side. About 1,500 specimens span- ning all possible species and from varying lithofacies were selected for further examination involving three- dimensional analysis. By matching peel to rock sur- face, these specimens were located on the actual hand samples and were cut out. Each zoarium was matched to the portion of its colony found on the non-polished side of the succeeding contiguous slab. This latter slab was sliced in half parallel to the other cuts so as to not destroy the polished face when cutting out the zooecial counterparts. Both pieces of individual zoaria were examined un- der a binocular microscope and oriented in such a manner that the best longitudinal, tangential, and trans- verse sections could be prepared from either or both of the zoarial samples. Where necessary, specimens were embedded in epoxy cubes for ease of handling and/or the preservation of morphological features found at the colony surface. These specimens were cut using a Raytech Blue Blazer ultrathin blade and sub- sequently ground, polished, and etched as noted above for the large hand samples. Tangential sections were frequently attained by making a cut near the colony periphery and grinding down to the surface using a diamond studded lap. Oriented sections of each zoar- ium were then placed on individual slides of 1.5 mm thick acetate for further study. Over 12,000 measurements were used in the quan- titative characterizations of taxa. On average, 11 col- onies per taxon, 6 characters per colony, and 5 repli- cates per character were measured. Characters measured included cavity diameters of autozooecia and mesozooecia, autozooecial wall thick- ness, number of autozooecia per square millimeter, di- ameters of acanthostyle laminar sheath and lumen, and colony diameter. Where appropriate, measurements were made in the exozone and endozone as well as within macular and non-macular regions. REPOSITORY OF SPECIMENS Holotypes, paratypes, hypotypes and colony rem- nants are deposited in the U.S. National Museum of Natural History (USNM), Smithsonian Institution, Washington, D.C. STRATIGRAPHIC COLLECTION LEVELS AND SPECIMEN IDENTIFICATION LABELS Norris Lake IV Section At the Norris Lake IV Section, the Carters/Hermit- age contact appears 52 ft (15.8 m) above the top of the T-3 Chert. The lowermost exposed bed of the un- derlying Carters Formation occurs 35 ft (10.7 m) above the T-3 Chert. This Carters bed is the horizon above which the specimen data were collected. The T-4 Chert occurs 19 ft (5.8 m) above the T-3 Chert. Typical label: NL IV_ 108(143)A-1-D(M) [USNM 432401] NL IV = Norris Lake IV section. 108 = The number of feet above the base of the exposed Carters Formation from which the specimen was collected. (143) = The corresponding number of feet above the top of the T-3 Chert. A = Hand sample indicator (A = first hand sam- ple from this horizon, B = second, etc.). 1 = Slab number from hand sample. Trepo- stome colony was noted from right side of slab unless otherwise indicated with an “L” (from left side). If slab was cut into two pieces, eagh was denoted (e.g., as ‘“‘a” or “b”), D = Trepostome colony indicator (A = first col- ony noted from slab, B = second colony, ... AA = 27th colony, etc.). (M) = Various measurements were made on this colony and they appear in the statistical ta- bles. (F) = Indicates material which was particularly fragmentary. [USNM 432401] = the specimen catalog number at the United States National Museum Chamberlain Branch Section At the Chamberlain Branch Section, the base of the exposed Hermitage appears 45 ft (13.7 m) above the top of the T-3 Chert. This chert is the horizon above which the specimen data were collected. The T-4 Chert occurs 34 ft (10.4 m) above the T-3 Chert. Typical label: CB 145B-4-A (F) CB = Chamberlain Branch section. 145 = The number of feet above the top of the T-3 Chert from which the specimen was collected. Other symbols are as for the Norris Lake IV Section above. MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH 9 Wilson Branch Section At the Wilson Branch Section, the base of the ex- posed Hermitage Formation appears 12 ft (3.7 m) above the top of the T-4 Chert. This base is the horizon above which the specimen was collected. The T-3 Chert is not visible but is estimated to occur at about 21 ft (6.4 m) below the level of the T-4. Typical label: WB 44(56)A-5-D (M) WB = Wilson Branch section. 44 = The number of feet above the base of the ex- posed Hermitage Formation from which the specimen was collected. (56) = The corresponding number of feet above the top of the T-4 Chert. Other symbols are as for the Norris Lake IV Section above. Howard Cemetery Section At the Howard Cemetery Section, the base of the exposed Hermitage Formation appears 39 ft (11.9 m) above the top of the T-3 Chert. This base is the horizon above which the specimen data were collected. The T-4 Chert occurs 30 ft (9.1 m) above the T-3 Chert. Typical label: HCM 43(82)B-3-A (M) HCM = Howard Cemetery section. 43 = The number of feet above the base of the exposed Hermitage Formation from which the specimen was collected. (82) = The corresponding number of feet above the top of the T-3 Chert. Other symbols are as for the Norris Lake IV Section THE HERMITAGE FORMATION GENERAL DISTRIBUTION AND SUBDIVISIONS The Hermitage is one of the more widespread for- mations of the Central Basin of Tennessee and contig- uous regions (Bassler, 1932, p. 74). It can be found east of the Tennessee River, throughout the Central Basin, and into Sequatchie Valley. The eastern bound- ary noted by Bassler (1932, p. 75), is “‘the western part of the Appalachian Valley from southwest Virgin- ia to Alabama.” To the north, the Hermitage is not found north of north-central Kentucky (Bassler, 1932, p. 75). To the south, strata of the Hermitage dip south- ward under sediments of the Gulf Coastal Plain. Safford (1869) originally referred to the beds of the present-day Hermitage Formation in central Tennessee as the “Orthis bed,” named for the preponderance of the brachiopod Orthis testudinaria, now designated Dalmanella fertilis. Specific designation as the Her- mitage Formation, and therefore of the type locality, was by Hayes and Ulrich (1903), who alluded to an outcrop located near Hermitage station, Davidson County, in central Tennessee, “‘near the old home of President Jackson on the Tennessee Central Rail- road, ...”’ Bassler (1932) specifically located and de- scribed this section (work completed with Ulrich in 1899 according to Bassler) as being composed of 67 feet (20.4 m) of thin-bedded, impure limestone with interbedded shales. In addition, Bassler recognized the Hermitage to be lithologically variable from county to county within the Central Basin of Tennessee but did not attempt to correlate the strata. He did, however, divide the Her- mitage into a minimum of eight faunal zones believed by him to be chronologically ordered but not persis- tently distributed throughout the region. Wilson (1949) studied several exposures of the Hermitage near its type locality and presented a com- plete composite of the formation with a total thick- ness approaching 70 feet (21.3 m). He proposed that the Hermitage could be divided into seven lithologic and faunal units, or members, and attempted to cor- relate the sections suggesting at the same time that Bassler’s faunal zones were not strictly temporally se- quential. Wilson’s basal unit was called the Curdsville Member, a name used to designate the lower Hermit- age in Kentucky. Succeeding the Curdsville and thickening to the west is the Laminated Argillaceous Member above which a Silty Nodular Limestone Member thickens to the east. The latter two members form the bulk of the Hermitage in Central Tennessee. Sandwiched in between the Laminated Argillaceous and Silty Nodular Limestone Members from west to east and generally increasing in age are four lenticular sedimentary bodies, the Dalmanella Coquina Mem- ber, Granular Phosphatic Member, Ctenodonta Mem- ber and Blue-Clay Shale Member. This type of strati- graphic framework would permit the Hermitage to exist as several members (or facies) at any one time (see Wilson, 1949, fig. 15, p. 84). Templeton and Willman (1963, p. 206), on the other hand, suggest that Wilson’s post-Curdsville Hermitage units are more stratigraphically successive than contempora- neous in their distribution. The overall thickness of the Hermitage in Central Tennessee varies from 50 to 70 feet (15.2 to 21.3 m) to the east and central with a rapid thickening to the west (Laminated Argillaceous Limestone Member) where it attains a maximum thickness of 180 feet (54.9 m) (Wilson, 1949). In northwestern Georgia, the Her- mitage is 35 feet thick (10.7 m) (Milici and Smith, 1969) and in southwest Virginia it is 150 feet thick (45.7 m) (Bassler, 1932). East of Grundy, Van Buren, 10 BULLETIN 353 STUDY AREA IN EASTERN TENNESSEE Nashville STUDY AREA °o O km. 64 =| O mi. 40 oF FAC és NLVi BY LEGEND i, NL IV = NORRIS LAKE IV j/— CB = CHAMBERLAIN BRANCH WB = WILSON BRANCH HCM = HOWARD CEMETERY ] = CHICKAMAUGA OUTCROP (including Hermitage Fm.) “= RIVER SYSTEM _—= FAULT CONTACT _—— = LITHOLOGIC CONTACT Text-figure 1.—Partial geologic map of the Tennessee Study Area indicating the locations of the four measured sections. and White counties of east-central Tennessee (nearly 90 miles (144.9 km) southeast of the type section), the Silty Nodular Limestone Member is the sole constit- uent of the Hermitage Formation (forming about 60 to 70 feet (18.3 to 21.3 m) of section in Sequatchie Val- ley; Milici, 1970). Variation in the above lithotypes was largely con- trolled by tectonic movements of the Cincinnati Arch or Nashville Dome (Wilson, 1962). The lesser amount of clastic (i.e., detrital) silt within the Silty Nodular Limestone member as compared to other members suggests a western to southwestern source area (Wil- son, 1949, p. 102). HERMITAGE OF THE STUDY AREA Within the study area at Sequatchie Valley (Text- figure 1), the Hermitage Formation is composed of 45 to 60 feet (13.7 to 18.3 m) of predominantly irregu- MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH 11 larly bedded, argillaceous, skeletal wackestones (sparse to packed biomicrites). Further to the east, at Norris Lake and Chamberlain Branch, the Hermitage is more variable in lithology and of greater thickness (between 100 and 130 feet; 30.5 and 39.6 m). Inter- spersed with lithologies similar to the Sequatchie Val- ley sections are irregularly bedded, clean to slightly argillaceous to argillaceous, fine-grained to coarse- grained packstones (packed biomicrites to poorly washed biosparites), and clean to slightly argillaceous wackestones (packed biomicrites). The Hermitage For- mation found in Sequatchie Valley would represent the Silty Nodular Limestone Member of Wilson (1949). The other sections are not so lithologically distinct as to merit a separate designation and are therefore in- cluded in this member. Several beds within these east- er sections, however, may be considered similar to Wilson’s Dalmanella Coquina Member of the Central Basin, in that scattered horizons contain concentrations of Dalmanella fertilis in such abundance that they form the greater part of the rock. STRATIGRAPHIC POSITION The Hermitage Formation is the lowermost of three units forming the Nashville Group. The Cannon Lime- stone overlies the Hermitage while the Carters Lime- stone, the uppermost unit of the Stones River Group, underlies the Hermitage. Both Groups form the Chick- amauga Supergroup (Milici and Smith, 1969; Milici, 1970) embracing the Black River and Trenton Stages of the Middle Ordovician. Twenhofel et al. (1954) placed the Hermitage of the Central Basin of Tennes- see within the middle of the Trentonian Stage (time- correlative with the “representative” Kirkfield and lower Sherman Falls Formations) of the Champlainian Series. In addition, Twenhofel et al. (1954) correlated the Hermitage with the lower half of the Lexington Limestone in Central Kentucky, and with the Ion Member of the Decorah Formation and Prosser For- mation in the Upper Mississippi Valley. Cooper (1956) placed the Hermitage of the Central Basin in his low- ermost Trenton Stage (Cooper’s Trenton is not the time-stratigraphic equivalent of the Trentonian Stage defined by Twenhofel et al., 1954) with the Carters Limestone being placed in his uppermost Wilderness Stage. According to Ross et al. (1982) (also see Sweet and Bergstrom, 1976), the Hermitage of the Central Basin of Tennessee (early Shermanian in age) is separated from the uppermost Carters Limestone (mid-Kirkfiel- dian) by an erosional unconformity (truncation of the upper Carters; see Wilson, 1949). In Sequatchie Val- ley, the Hermitage (in apparent conformity with the Carters Limestone) spans the greater part of both the Rocklandian and Kirkfieldian Stages (and possibly the lowermost Shermanian). The present author finds these correlations of Ross et al. to be suspect in part. The position of the T-3 Bentonite in the upper Carters Limestone (found close to the overlying Hermitage) was personally observed to occur in the Central Basin, Sequatchie Valley, and western Valley and Ridge, of- fering rather strong evidence of the time-equivalence of the upper Carters and hence the lower Hermitage boundary across this area. Kolata et al. (1987) noted that the T-3 and T-4 Bentonites of the upper Carters Limestone appear to correlate on geophysical logs with the Deicke and Millbrig Bentonites (early Rock- landian Age) in the lower Decorah Formation of the Upper Mississippi Valley. Samson et al. (1987) used chemical correlation methods to corroborate this lat- eral relationship. This is more in line with the chron- ostratigraphic correlations for the Hermitage suggested above for Sequatchie Valley. Votaw in Fetzer (1973) found the lowest representatives of the conodont Phragmodus undatus in the lowermost Hermitage of Central Tennessee suggesting a Rocklandian age (low- er Midcontinent Conodont Zone 8) for these basal beds, again, not inconsistent with the correlations sug- gested directly above. GENERAL DEPOSITIONAL SETTINGS OF THE HERMITAGE FORMATION AND STRATIGRAPHICALLY CONTIGUOUS STRATA Within the study area, the Carters Limestone under- lies the Hermitage Formation. Wilson (1949) divided the Carters into two formal members, an Upper and Lower, separated by the T-3 bentonite bed. At sections east of Sequatchie Valley, the exposed Upper Carters is largely pinkish to maroon and olive grey mudstone with 2 to 8 inch (5.1 to 20.3 cm) regular and even beds. Laminations and mudcracks are scattered throughout. At Davis Crossroads, Georgia, beds of the Upper Carters vary in thickness from 1 to 8 inches (2.5 to 20.3 cm), are even and regular, commonly cal- cilutitic, and contain varying amounts of birdseye and dessication structures, intraclasts, ostracods, and ver- tical burrows. In addition, Milici and Smith (1969) noted the presence of mudcracks and fine crossbeds. In Sequatchie Valley, Milici (1970) noted the presence of mudcracks, laminations, and intraclasts in fine- grained (calcilutite to calcisiltite) limestones, in beds generally 1 to 6 inches (2.5 to 15.2 cm) thick, even and irregularly bedded. The presence of mudcracks, birdseye features, lam- inations and vertical burrows, depauperate fauna, fine- scale cross-stratification and intraclasts would certainly suggest intertidal to supratidal conditions (see Walker and Laporte, 1970; Laporte, 1971, for summaries of 12 BULLETIN 353 environmental criteria for carbonate regimes) existing throughout the Upper Carters Limestone and across a huge expanse of carbonate platform prior to deposition of the Hermitage Formation. The onset of Hermitage deposition is marked by the presence of more argillaceous and irregular beds with an abundant and diverse invertebrate fauna. Positions of the lower Hermitage boundary with respect to Wil- son’s T-4 Bentonite strongly suggest the rapid relative subsidence of the carbonate platform, perhaps related to a general worldwide rise in sea level (see Vail et al., 1977) and consequent invasion of a normal marine biota into newly developing habitats. Within the Hermitage of the study area, the striking lithological difference among outcrops is the almost total restriction of an argillaceous wackestone (sparse, or sparse to packed biomicrite) lithofacies to strata of Sequatchie Valley. The only exceptions to this are sparitic limestone beds containing relatively large amounts of detrital silt and sand in the lowermost beds of each section. Typical ‘‘Sequatchie-looking”’ strata (fairly argillaceous and rubbly weathering) in the two eastern sections are relatively few, being limited to ap- proximately the upper fifth of the Hermitage Forma- tion at Norris Lake, and perhaps small portions in the middle and uppermost levels of the Chamberlain Branch Hermitage. Other rocks of the Hermitage For- mation in these eastern sections are predominantly packstones (packed biomicrites) with varying amounts of argillaceous sediment or wackestones (packed biomicrites) with some argillaceous input that are near- ly packstones. The tendency for grain support within the eastern sections suggests that they were deposited in more ag- itated waters than those at Sequatchie Valley (a fact further supported by the presence of some crossbeds at both eastern sections). The subtle differences in lith- ofacies are strikingly amplified in the distribution of several prominent macroinvertebrate species. The two major brachiopod taxa abundantly distributed within Norris Lake and Chamberlain Branch sections include Sowerbyella sp. and Dalmanella fertilis, neither of which is found in the Hermitage of Sequatchie Valley. While the distribution of the bryozoan fauna will be elaborated elsewhere in this text, the strikingly obvious hemispherical-shaped colonies of Prasopora and Me- sotrypa, common to certain strata of the eastern sec- tions are totally absent in Sequatchie Valley save for two colonies of Mesotrypa. These massive encrusting growth forms further suggest an adaptation of taxa able to withstand a more physically mgorous wave- swept environment. Indeed, even within individual sections to the east, the presence or absence of these two co-occurring genera is reflected by the associated fauna and lithofacies. Rhynchotrema increbescens, on the other hand, the common brachiopod of the Se- quatchie Valley Hermitage, is found scattered in small numbers within beds of eastern sections having wacke- stones with relatively high amounts of argillaceous de- tritus. The point is that several different lithological subfacies exist within the Hermitage reflecting varia- tions and combinations of water depth, wave or current energy, amounts of terrigenous detritus, and type and amount of carbonate materials produced within the ba- sin. The sediments to the east were, in general, sub- jected to a higher degree of reworking due to higher energy conditions allowing for the development of a packstone fabric. The Cannon Limestone overlying the Hermitage is generally a clean wackestone (sparse to packed bio- micrite) in the eastern sections. In Sequatchie Valley as well as northwest Georgia, lithologies contain more carbonate mudstone (fossiliferous micrites). The Can- non, for the most part, supports a normal marine fauna. Sections examined south of Howard Cemetery include some beds containing leperditid ostracods and birdseye structures, suggestive of at least intertidal conditions. The general increase in carbonate mud within the Can- non compared to the Hermitage would indicate more quiet waters prevalent during deposition of these sed- iments. The intermingling of features indicative of in- tertidal or supratidal environments with the more fully marine strata is suggestive of generally shallower-wa- ter conditions than for the Hermitage, at least for sev- eral localities in Sequatchie Valley and northwestern Georgia. In addition, the general association of the tab- ulate coral Tetradium, leperditid ostracods, archaeo- gastropods (Hormotoma), the spiriferid brachiopod Zygospira, and some cryptostome bryozoans found es- pecially in certain Cannon beds south of Howard Cem- etery is a recurrent one in marine facies interpreted to be shoreward of Ordovician carbonates level-bottom faunas (Walker, 1972; Longman and Sprinkle, 1976; Cameron and Kamal, 1977). Rocks having this general faunal association are here considered to represent the shallowest-water environments of the study area ca- pable of supporting invertebrate life. Elsewhere within the Cannon, the increased prominence of a molluscan fauna is supportive of a shallower water (nearshore) interpretation (see Bretsky, 1969; Berry, 1974). This is no doubt due in part to ecological constraints re- sulting from the shoreward accumulation of lime muds commonly associated with epicontinental sedimenta- tion (see Irwin, 1965; Heckel, 1972) and/or an in- creased suitability for more eurytypic molluscan spe- cies. MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH 1S TREPOSTOME BRYOZOAN FAUNAL ANALYSIS TREPOSTOME BRYOZOAN ASSEMBLAGES FROM THE HERMITAGE FORMATION OF THE EASTERN TENNESSEE STUDY AREA Three groups of trepostome bryozoan species pop- ulations were observed to regularly occur in time (within specific stratigraphic intervals) and space (over several geographic localities) and are referred to herein as Bryozoan Assemblages One, Two, and Three. Each is presumed to largely reflect similar species responses to particular environmental demands. Bryozoan Assemblage One This assemblage is numerically dominated by By- thopora dendrina (39%), Eridotrypa mutabilis (11%), and Parvohallopora pulchella (10%), with lesser Het- erotrypa subtrentonensis (4%), Stigmatella distincta- spinosa (4%), Tarphophragma multitabulata (3%), Homotrypa flabellaris var. spinifera (3%), Mesotrypa angularis (3%), and Parvohallopora granda (3%) (comprising 80% of the total trepostome fauna) (Table 5). It occurs at all four study localities (Text-fig. 6) within the following sampling intervals—Norris Lake IV 19—40 ft (5.8—12.2 m), 61-73 ft (18.6—22.2 m), 85- 87 ft (25.9-26.5 m) (Table 1; Text-fig. 2), Chamberlain Branch 41—46 ft (12.5-14.0 m), 67-79 ft (20.4—24.1 m), 114—132 ft (34.8—40.2 m), 149-161 ft (45.4—49.1 m) (Table 2; Text-fig. 3), Wilson Branch 2-32 ft (0.6— 9.8 m) (Table 3; Text-fig. 4), and Howard Cemetery 3-11 ft (0.9-3.4 m) (Table 4; Text-fig. 5). Of particular note is the relative paucity of Eridotrypa mutabilis at the two western sections (Howard Cemetery and Wil- son Branch), of Heterotrypa subtrentonensis at Norris Lake IV, and of Parvohallopora pulchella at Cham- berlain Branch and Howard Cemetery. Other benthic invertebrates generally preserved with Assemblage One at Norris Lake and Chamberlain Branch are large numbers of Dalmanella fertilis and lesser numbers of Rafinesquina hermitagensis, Sow- erbyella sp., various strophomenoids, pelmatozoan columnals, and occasional Rhynchotrema increbescens (where especially argillaceous). Within Sequatchie Valley to the west (at Howard Cemetery and Wilson Branch) non-bryozoan elements commonly associated with Assemblage One are R. increbescens, pelmato- zoan columnals, and Zygospira recurvirostra. Associated lithologies within the western sections of Sequatchie Valley are predominantly wackestone (sparse/packed biomicrite) to wackestone (packed biomicrite). Within the eastern sections at Norris Lake IV and Chamberlain Branch lithologies are primarily packstone (nearly wackestone; packed biomicrite) with lesser amounts of cleaner packstone and, then, wacke- stone (nearly packstone; packed biomicrite). Rocks as- sociated with Assemblage One generally are fairly clean throughout the study area though some strata, especially in the western sections, are somewhat ar- gillaceous. Environmental Interpretation—The packstones (packed biomicrite), generally large allochems (mainly brachiopods), and occasional coquinite beds at Norris Lake IV suggest a relatively high energy environment, perhaps a moderately agitated open shelf. At the west- erm outcrops, predominantly wackestones with minor interbeds of packstone (poorly washed biosparite) and fine-grained wackestones with terrigenous silt suggests intermittent mild turbulence in an overall moderately quiet water environment. Bryozoan Assemblage Two This assemblage is composed primarily of Bytho- pora dendrina (31%), Eridotrypa mutabilis (17%), An- aphragma hermitagensis (16%), Mesotrypa angularis (9%), Prasopora falesi (6%), Tarphophragma ampla (3%) and Heterotrypa subtrentonensis (3%) (cumula- tively 85%) (Table 6). It occurs over three sampling intervals (Text-figure 6) only within the eastern sec- tions—Norris Lake IV 43-51 ft (13.1—15.5 m) (Table 1; Text-fig. 2), and Chamberlain Branch 50-62 ft (15.2-18.9 m), 138-145 ft (42.1—44.2 m) (Table 2; Text-fig. 3). Dalmanella fertilis, Rafinesquina hermi- tagensis, Sowerbyella sp., and Dinorthis pectinella are common faunal associates. Lithologies associated with this fossil material con- sist primarily of packstone (packed biomicrite) with lesser amounts of packstone (nearly a wackestone; packed biomicrite). Argillaceous input is variable but in general is higher than for Assemblage One. Environmental Interpretation—The density of shell material, the massive zoaria of many trepostomes (in- cluding the only two common hemispherical-shaped species in the study area, Prasopora falesi and Me- sotrypa angularis), size-sorted beds of Dalmanella fer- tilis (diameter approximately 10 mm), and presence of cross-bedding leave no doubt of a current-swept, rel- atively high energy (highest of the three assemblages), open marine, shallow shelf environment. Bryozoan Assemblage Three Abundant and commonly associated trepostomes of this assemblage include Batostomella subgracilis (30%), Bythopora dendrina (16%), Homotrypa flabel- laris var. spinifera (12%), Parvohallopora granda vat. inflata (7%), P. granda (7%), and Homotrypa subra- mosa (3%), and Parvohallopora pulchella (3%) (cu- mulatively 78%) (Table 7). This association of species occurs within a single 14 BULLETIN 353 Table 1.—Relative abundances of common trepostome species (= 3%) within Bryozoan Assemblages found at Norris Lake IV section arranged in stratigraphic order. Inter. = stratigraphic interval in feet above the base of measured section from which data were gathered; Assem. = Bryozoan Assemblage Number; Species present = a listing of trepostome species occurring in abundances = 3%; Specimens = number of individuals of each species as counted from acetate peels; % = percentage abundance of each trepostome species; Cum. % = cumulative percentage. Inter. Assem. Species present Specimens % Cum. % 19—40 ft 1 Bythopora dendrina 65 67.7 67.7 (5.8-12.2 m) Eridotrypa mutabilis 8 8.3 76.0 Anaphragma hermitagensis 6 6.2 82.2 Stigmatella distinctaspinosa 5 SE2 87.4 Homotrypa similis 4 4.2 91.6 Mesotrypa angularis 3} Sel 94.7 Other species (each < 3.0%) =) a? 9939) [Total: 9 genera/11 species] Total 96 99.9 43-51 ft 2 Bythopora dendrina 194 27.3 27.3 (13.1-15.5 m) Eridotrypa mutabilis 148 20.8 48.1 Anaphragma hermitagensis 136 19.2 67.3 Mesotrypa angularis 71 10.0 TRS Prasopora falesi 42 5.9 83.2 Tarphophragma ampla 28 B19 87.1 Other species (each < 3.0%) Ot 12.8 99.9 {Total: 14 genera/20 species] Total 710 99.9 61-73 ft 1 Bythopora dendrina 169 26.8 26.8 (18.6—22.2 m) Eridotrypa mutabilis 132 21.0 47.8 Parvohallopora pulchella 115 18.2 66.0 Homotrypa flabellaris var. spinifera 40 6.3 72.3 Mesotrypa angularis 35 5.6 VUE) Peronopora mundula 30 4.8 82.7 Tarphophragma multitabulata 23 3.6 86.3 Stigmatella distinctaspinosa 23 3.6 89.9 Other species (each < 3.0%) M63) 10.0 99.9 [Total: 14 genera/22 species] Total 630 99.9 85-87 ft 1 Bythopora dendrina 52 46.8 46.8 (25.9-26.5 m) Eridotrypa mutabilis 22 19.8 66.6 Stigmatella distinctaspinosa 9 8.1 74.7 Mesotrypa angularis 6 5.4 80.1 Heterotrypa subtrentonensis 4 3.6 83.7 Other species (each < 3.0%) 18 16.2 99.9 {Total: 10 genera/15 species] Total 111 99.9 93-117 ft 3 Batostomella subgracilis 506 37.2 37.2 (28.4—-35.7 m) Parvohallopora granda vat. inflata 144 10.6 47.8 Bythopora dendrina 140 10.3 58.1 Homotrypa flabellaris var. spinifera 126 9.3 67.4 Parvohallopora granda 116 8.5 M539, Tarphophragma multitabulata 40 AS) 78.8 Other species (each < 3.0%) _288 Prep? 100.0 (Total: 14 genera/27 species] Total 1360 100.0 interval at each stratigraphic section of the study area (Text-fig. 6)—Norris Lake IV 93-117 ft (28.4—35.7 m) (Table 1; Text-fig. 2) and Chamberlain Branch 81—85 ft (24.7—25.9 m) (Table 2; Text-fig. 3) to the east, and Wilson Branch 38—44 ft (11.6—13.4 m) (Table 3; Text- fig. 4) and Howard Cemetery 18 ft (5.5 m), 38—43 ft (11.6—13.1 m) (Table 4; Text-fig. 5) to the west. Associated non-trepostome faunal elements. com- monly include Rhynchotrema increbescens and pel- matozoan columnals (these commonly co-occur with argillaceous carbonates). Some Dalmanella fertilis and/or Sowerbyella sp. are noticeable in the eastern sections at Norris Lake IV and Chamberlain Branch. Lithologies at the western outcrops are wackestone (sparse biomicrite to sparse/packed biomicrite). Within the eastern outcrops, lithologies are mainly packstone (nearly wackestone; packed biomicrite) with somewhat lesser amounts of wackestone (nearly packstone; MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH 15 NORRIS LAKE IV (ft) 93-II7 85-87 61-73 43-5 19-40 g 2 = 7 < ” 3 a . Ss > 2 x S > oD TS SSVS SSNS a is — KSSSSo) [lesa as) Text-figure 2.—Graphic display illustrating the relative abundances of common trepostome species (= 3%) within Bryozoan Assemblages found at the Norris Lake IV section. Percent occurrences are rounded off to the nearest 5%. The bar graph is solid if the actual occurrence of a species is = 5%. The graph is cross-hatched if = 3% and < 5%. A single vertical line indicates an occurrence < 3%. Endpoints of vertical species distributions delimit the actual biostratigraphic ranges within the section. Numbers to the left indicate the stratigraphic intervals (in feet above the base of measured section) containing the various Bryozoan Assemblages. See section on Stratigraphic Collection Levels (p. 8) as well as section on Trepostome Bryozoan Assemblages (p. 13) for more precise stratigraphic information and metric equivalents. packed biomicrite) and, then, cleaner packstone. Across the entire study area, argillaceous input is rel- atively higher for this assemblage than for either of the other two. Environmental Interpretation—The relatively large amount of wackestone in this assemblage suggests generally low energy conditions (lowest of the three assemblages). Packstone fabrics in the eastern outcrops indicate periodic moderate agitation. Pulses of argil- laceous sediment are common. Concentrations of clas- tic material are enhanced due to relatively quiet water reducing the winnowing of fine-grained sediment (see Table 8 for a summary of Bryozoan Assemblages and their relation to associated lithotypes, macrofossils, and environments of deposition). COMPARISON WITH SOME OTHER MIDDLE ORDOVICIAN BRYOZOAN ASSEMBLAGES Only a handful of studies in recent years have de- scribed in any detail assemblages of trepostome bry- ozoans present within well-defined intervals of time and space. In one of the most recent reports of this type, Karklins (1984) described both the trepostome and cystoporate bryozoans from the Lexington Lime- stone and the Clays Ferry Formation (Middle and Up- per Ordovician, respectively) of northern Kentucky. This study noted the precise stratigraphic distributions of the trepostomes and cystoporates, and attempted to quantify their relative abundances. Karklins (1984, p. 18) defined two bryozoan assem- blage zones, each based on the “restricted vertical ranges and geographic occurrences of individual taxa.”” The Tarphophragma multitabulata assemblage zone includes upper parts of the Curdsville, as well as the Logana and Grier Members of the Lexington Limestone and a few feet of the overlying rock units (stratigraphically equivalent to the lowermost part of the Brannon Member). This assemblage zone includes nine characteristic species. The base of the interval is placed at the lowermost known occurrence of 7. mul- titabulata. The top is defined by the first appearances of species characteristic of the succeeding Constellaria teres assemblage zone. Not all species of the 7. mul- titabulata zone are restricted to it, some disappear slightly above the top of the interval. According to correlations in Ross et al. (1982) and Karklins (1984), that portion of the Lexington Lime- stone represented by the Tarphophragma multitabu- 16 BULLETIN 353 Table 2.—Relative abundances of common trepostome species (= 3%) within Bryozoan Assemblages at Chamberlain Branch section arranged in stratigraphic order. See Table | for explanation of column headings and abbreviations used. Inter. Assem. Species present Specimens % Cum. % 41—46 ft 1 Bythopora dendrina 74 56.9 56.9 (12.5—14.0 m) Eridotrypa mutabilis 8 6.2 63.1 Homotrypa minnesotensis 7 5.4 68.5 Homotrypa tuberculata 7 5.4 13:9) Heterotrypa subtrentonensis 7 5.4 19:3 Tarphophragma multitabulata 4 3.1 82.4 Other species (each < 3.0%) 23) _ ited 100.1 [Total: 9 genera/16 species] Total 130 100.1 50-62 ft Z Bythopora dendrina 67 34.2 34.2 (15.2-18.9 m) Eridotrypa mutabilis 20 10.2 44.2 Anaphragma hermitagensis 19 Oey 54.1 Heterotrypa subtrentonensis 17 8.7 62.8 Prasopora falesi 13 6.6 69.4 Mesotrypa angularis 13 6.6 76.0 Homotrypa subramosa 7 3.6 79.6 Tarphophragma ampla 6 31 82.7 Homotrypa tabulata 6 Syl 85.8 Other species (each < 3.0%) m28) 14.3 100.1 [Total: 14 genera/22 species] Total 196 100.1 67-79 ft 1 Bythopora dendrina 127 43.5 43.5 (20.4—24.1 m) Eridotrypa mutabilis 25 8.6 52.1 Parvohallopora granda 23 7.9 60.0 Tarphophragma multitabulata 16 SES) 65.5 Heterotrypa subtrentonensis 16 SYS) 71.0 Parvohallopora pulchella 13 4.4 75.4 Mesotrypa angularis 13 4.4 79.8 Heterotrypa magnopora 12 4.1 83.9 Homotrypa flabellaris var. spinifera 10 3.4 87.3 Other species (each < 3.0%) Sill SPAT 100.0 [Total: 13 genera/23 species] Total 292 100.0 81-85 ft 3 Batostomella subgracilis 47 26.2 26.2 (24.7-25.9 m) Bythopora dendrina 44 24.6 50.8 Homotrypa flabellaris var. spinifera 21 NET, 62.5 Parvohallopora granda 14 7.8 70.3 Tarphophragma multitabulata 11 6.1 76.4 Mesotrypa angularis 7 3.9 80.3 Other species (each < 3.0%) B35) 19.6 99.9 [Total: 11 genera/17 species] Total 179 99.9 114-132 ft 1 Bythopora dendrina 145 47.4 47.4 (34.8—40.2 m) Eridotrypa mutabilis 26 8.5 55.9 Heterotrypa subtrentonensis 16 52 61.1 Anaphragma hermitagensis 16 5.2 66.3 Tarphophragma multitabulata 12 39 70.2 Homotrypa minnesotensis 11 3.6 73.8 Other species (each < 3.0%) _80 26.1 99.9 (Total: 14 genera/27 species] Total 306 99.9 138-145 ft 2 Bythopora dendrina 60 44.8 44.8 (42.1—44.2 m) Anaphragma hermitagensis 12 9.0 53.8 Mesotrypa angularis 10 75 61.3 Eridotrypa mutabilis 9 6.7 68.0 Heterotrypa subtrentonensis 6 4.5 W2-D Homotrypa minnesotensis 5 Shy 76.2 Prasopora falesi 5 367/ 79.9 Tarphophragma multitabulata 4 3.0 82.9 Heterotrypa praenuntia var. simplex 4 3.0 85.9 Cyphotrypa acervulosa 4 3.0 88.9 Other species (each < 3.0%) 15) ile? 100.1 [Total: 14 genera/21 species] Total 134 100.1 MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH Table 2.—Continued. 17 Inter. Assem. Species present Specimens % Cum. % 149-161 ft 1 Bythopora dendrina 92 41.2 41.2 (45.4—49.1 m) Heterotrypa subtrentonensis 21 9.4 50.6 Parvohallopora granda 20 9.0 59.6 Eridotrypa mutabilis 14 6.3 65.9 Tarphophragma multitabulata 14 6.3 222 Parvohallopora pulchella 13 5.8 78.0 Heterotrypa magnopora 10 4.5 82.5 Homotrypa flabellaris var. spinifera 7 Shi 85.6 Peronopora weirae 7 3.1 88.7 Other species (each < 3.0%) 225) WN 99.9 Total 223 99.9 (Total: 13 genera/21 species] lata zone (Kirkfieldian to mid-Shermanian; Curdsville through Grier Members) is largely coincident with the Hermitage and Cannon Formations of Sequatchie Val- ley (and the Hermitage and upper Carters of the Cen- tral Basin). Nine (to possibly 11) trepostome species are described by Karklins (1984) to occur in the in- terval approximately time-equivalent to the Hermitage of the study area. Six of these are considered by Kark- lins to be characteristic of the Tarphophragma multi- tabulata zone. Four of the nine (or five of the 11) are found within the eastern sections (Norris Lake IV and Chamberlain Branch) and all four (or four of the five), namely Tarphophragma multitabulata, Mesotrypa an- gularis, Prasopora falesi, and Cyphotrypa acervulosa, are within Karklins’ group of six characteristic species. Tarphophragma multitabulata, and M. angularis are rare in the western sections at Wilson Branch and Howard Cemetery (Sequatchie Valley) while P. falesi and C. acervulosa do not occur there at all. Since the similar stratigraphic positions of the Sequatchie Valley and eastern sections above the T-3 Bentonite (a pre- sumably time-equivalent horizon) strongly suggest a temporal correspondence among outcrops of the study area, the varying faunal occurrences and abundances could be the result of one or more factors. These in- clude differential sampling (especially where portions x wY CHAMBERLAIN BRANCH a & & £ Pi 2 o € o : 0 25 50% s&s § 2 ° Qe 5 5 ao © S Bios 2 Ore te veneers O59 = = 52 So ° SIG 5.5 55 Sols = | = ao 2S Ss =~ OA GS SSS Sap SOBs RSS ore pS S = Se se) S & PSEh28. S§ SELL S BS £ © SES2s 5 pecess es esese 2 o jac GS SSSR CESS Ss ‘2 9 ae icy Sees SCS o OF HS QS GSS oe ees 5 5 SS soo sae oaos Sass 8 & a mee FS DY ee SSS OS Cos GES oS << ocese ~ & ty /D S © Ssgeong § 5 PEL OS io = ISLS meas gS ase ee SSE&E § Assem a (ft) a) ay a a Se: aga ® 149-16] gZ 138-145 4 114-132 81-85 es i 67-79 4 4l-46 Text-figure 3.—Graphic display illustrating the relative abundances of common trepostome species (= 3%) within Bryozoan Assemblages found at the Chamberlain Branch section. See Text-figure 2 for explanation of symbols used 18 BULLETIN 353 Table 3.—Relative abundances of common trepostome species (= 3%) within Bryozoan Assemblages at Wilson Branch section arranged in stratigraphic order. See Table | for explanation of column headings and abbreviations used. Inter. Assem. Species present Specimens % Cum. % 2-32 ft 1 Parvohallopora pulchella 61 27.4 27.4 (0.6—9.8 m) Bythopora dendrina 44 19.7 47.1 Heterotrypa subtrentonensis 25 11.2 58.3 Homotrypa subramosa 11 4.9 63.2 Heterotrypa praenuntia var. echinata 9 4.0 67.2 Stigmatella distinctaspinosa 9 4.0 he: Acantholaminatus typicus 8 3.6 74.8 Other species (< 3.0%) _56 25.1 9919 [Total: 11 genera/17 species] Total 223 99.9 38-44 ft 3 Bythopora dendrina 97 36.0 36.0 (11.6—-13.4 m) Batostomella subgracilis 51 19.0 55.0 Homotrypa subramosa 32 11.9 66.9 Homotrypa flabellaris var. spinifera 6 5.9 72.8 Parvohallopora granda vat. inflata 11 4.1 76.9 Parvohallopora pulchella 9 3.3 89.2 Other species (each < 3.0%) 258) 19.7 99.9 [Total: 11 genera/17 species] Total 269 99'9 of sections are covered), paleoecological control, or faunal provincialism (explanations also invoked by Karklins, 1984, to explain the lack of similarity among the bryozoan faunas of the eastern United States Or- dovician carbonate platform). It is noteworthy that three of the above four species (Prasopora falesi, Me- sotrypa angularis, and Cyphotrypa acervulosa) are most common to Bryozoan Assemblage Two. This as- semblage is the only one found exclusively in the east- ern sections and is associated with relatively high en- WILSON BRANCH Text-figure 4.—Graphic display illustrating the relative abun- dances of common trepostome species (= 3%) within Bryozoan As- semblages found at the Wilson Branch section. See Text-figure 2 for an explanation of symbols used. ergy environments absent in the Hermitage of Se- quatchie Valley. The remaining three (of nine) species considered by Karklins (1984) to be characteristic of the Kentucky Tarphophragma multitabulata zone (Cyphotrypa switzeriensis, Balticopora arcuatilis, and Stigmatella sp.) are the three stratigraphically highest taxonomic occurrences in that area, restricted to the upper few feet of this assemblage zone. Since they are absent in the present study area, this would suggest a corre- spondence between the Hermitage Formation of East- Central Tennessee and an interval within the greater portion of the Tarphophragma multitabulata zone. The similarity between the Tarphophragma multi- tabulata zone of Karklins (1984) and the trepostome bryozoans of the Norris Lake ITV and Chamberlain Branch sections is not intended to define a strict time- equivalence between the Kentucky and Tennessee sec- tions (though such a relationship is supported by Ross et al. (1982). It is merely meant to point out a faunal resemblance suggestive of either a temporal corre- spondence or a general similarity in ecological control of faunal distribution. This is the case for all compar- isons drawn below. Where possible, time-equivalence based on the correlations of Ross et al. (1982) is noted. Brown (1965) reviewed the trepostomatous fauna from the ““Logana and Jessamine Limestones” (= Lo- gana and Grier Members of current usage according to Karklins, 1984) of the Lexington Limestone of Cen- tral Kentucky. He described 20 species and one sub- species, including 13 genera. Five of these 20 species are found in the present study area. These include Tar- Phophragma multitabulata (as Hallopora multitabu- MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH 19 Table 4.—Relative abundances of common trepostome species (= 3%) within Bryozoan Assemblages at Howard Cemetery section arranged in stratigraphic order. See Table | for explanation of the column headings and abbreviations used. Inter. Assem. Species present Specimens % Cum. % 3-11 ft 1 Bythopora dendrina 68 53.5 S15}9) (0.9-3.4 m) Tarphophragma ampla 9 Tesh 60.6 Homotrypa subramosa 9 7.1 67.7 Anaphragma hermitagensis W S)5) Bk? Stigmatella distinctaspinosa 7 Si) 78.7 Heterotrypa subtrentonensis 6 47 83.4 Homotrypa tuberculata 5) 3.9) 87.3 Other species (each < 3.0%) _16 12.6 99.9 [Total: 10 genera/15 species] Total 127 99.9 18, 38—43 ft 3 Homotrypa flabellaris var. spinifera 108 28.2 28.2 (5.5, 11.6—13.1 m) Bythopora dendrina 78 20.4 48.6 Batostomella subgracilis a1 if3}.3} 61.9 Homotrypa subramosa 22 S7/ 67.6 Homotrypa tuberculata 2A SE) Wakil Acantholaminatus typicus 21 Sy) 78.6 Parvohallopora pulchella 18 4.7 83.3 Parvohallopora granda 12 Sh 86.4 Other species (each < 3.0%) B52, _ 13.6 100.0 [Total: 12 genera/18 species] Total 383 100.0 lata), Prasopora falesi, Eridotrypa mutabilis (as Eri- dotrypa aedilis), Cyphotrypa acervulosa, and Peron- opora mundula (as Homotrypella mundula). These are taxonomically similar to Karklins’ (1984) Tarpho- phragma multitabulata zone. In fact, Brown noted Tarphophragma multitabulata, Prasopora falesi, and Eridotrypa mutabilis, three of the more common fau- nal elements described in the present report, to be some of the most abundant and well-characterized fau- nal components of his study area. Bork and Perry (1967, 1968a,b) studied the trepos- tome fauna of the Ion and Guttenberg Formations HOWARD CEMETERY Prt 0 25 50% Text-figure 5.—Graphic display illustrating the relative abun- dances of common trepostome species (= 3%) within Bryozoan As- semblages found at the Howard Cemetery section. See Text-figure 2 for explanation of symbols used. (lower Trentonian of Twenhofel ef al., 1954; mainly lower Kirkfieldian of Ross et al., 1982) from north- western Illinois and adjacent Wisconsin and Iowa where it lies stratigraphically above the Spechts Ferry Formation and is the time-equivalent to part of the Hermitage Formation in Sequatchie Valley (Ross et al., 1982). Thirty species (34 taxa including varieties and subspecies), and 14 genera are present of which four species-group taxa are common within East-Cen- tral Tennessee—Heterotrypa praenuntia vars. simplex and echinata, Homotrypa similis, and Homotrypa sub- ramosa. Bork and Perry (1968b) also describe the oc- currence of Prasopora simulatrix in the same strata. Their specimens, however, are lacking acanthostyles and thereby are not synonymized with P. falesi de- scribed herein. Perry (1962) examined the bryozoan fauna from the Spechts Ferry Formation (lowermost Trentonian of Twenhofel et al., 1954; predominantly mid to upper Rocklandian according to Ross et al., 1982) of north- western Illinois, southwestern Wisconsin, and south- eastern Iowa. He described 10 species, one variety, and seven genera of trepostomes. Only two of his de- scribed species are found in Tennessee, namely, Pra- sopora falesi (as Prasopora simulatrix var. orientalis) and Heterotrypa praenuntia var. echinata (as Dekay- ella praenuntia var. echinata). Neither is particularly common in the Spechts Ferry. This formation is rough- ly time-equivalent to the very lowermost Hermitage Formation in Sequatchie Valley (Ross et al., 1982). Ross (1967a,b, 1969, 1970) described 22 trepostome 20 BULLETIN 353 Table 5.—Relative abundances of common trepostome species found within representative samples of Bryozoan Assemblage One. Column headings indicate the stratigraphic intervals (ft and m) within which the particular Bryozoan Assemblage occurs. NL TV = Norris Lake IV Section; CB = Chamberlain Branch Section; WB = Wilson Branch Section; HCM = Howard Cemetery Section. Numbers in parentheses indicate the percent abundances of each species occurring within the specified stratigraphic interval. Numbers not within parentheses are the totals of individual specimens per species counted within the interval in question. Dashes instead of a numerical value indicates that the species was absent to less than 1.0% in abundance within selected representative samples from which relative percentages were calculated. Column totals account for all specimens, including those with abundances less than 1%. A = species totally absent from all samples collected within the stratigraphic interval, including those not used in the above calculations. NL IV NL IV NL IV Total (ft) 19-40 61-73 85-87 NL IV Species present (m) (5.8-12.2) (18.6—22.2) (25.9-26.5) Total Bythopora dendrina 836 (39.1) 65 (67.7) 169 (26.8) 52 (46.8) 286 (34.2) Eridotrypa mutabilis 237 (11.1) 8 (8.3) 132 (21.0) 22 (19.8) 162 (19.4) Parvohallopora pulchella 212 (9.9) Dial) 115 (18.2) — 118 (14.1) Heterotrypa subtrentonensis 95 (4.4) — — 4 (3.6) — Stigmatella distinctaspinosa 75 (3.5) 5:22) 23 (3.6) 9 (8.1) 37 (4.4) Tarphophragma multitabulata 70 (3.3) A 23 (3.6) — 24 (2.9) H. flabellaris var. spinifera 69 (3.2) A 40 (6.3) -- 41 (4.9) Mesotrypa angularis 63 (2.9) 318-1) 35)(3:5) 6 (5.4) 44 (5.2) Parvohallopora granda 53 (2.5) A = 2 (1.8) = Anaphragma hermitagensis 52 (2.4) 6 (6.2) 6 (1.0) A 12 (1.4) Heterotrypa magnopora 38 (1.8) A = 3 (2.7) 8 (1.0) Peronopora mundula 38 (1.8) A 30 (4.8) A 30 (3.6) Homotrypa tuberculata 37 (1.7) A — 3 (2.7) — Tarphophragma ampla 35 (1.6) 1 (1.0) 16 (2.5) — 18 (2.2) Homotrypa subramosa 31 (1.5) 1 (1.0) A — = Peronopora weirae 25 (1.2) A baler) A 11 (1.3) Homotrypa minnesotensis 21 (1.0) 1 (1.0) — A = Acantholaminatus typicus — A — A — H. praenuntia var. echinata — A — A = Homotrypa similis — 4 (4.2) — A = Other species 118 (5.5) — 16 (2.5) 5 (4.5) 21 (2.5) Column Totals 2138 96 630 111 837 CB CB CB CB CB Species present (ft) 41-46 67-79 114-132 149-161 Total (m) (12.5-14.0) (20.4—24.1) (34.8—40.2) (45.4—49.1) Bythopora dendrina 74 (56.9) 127 (43.5) 145 (47.4) 92 (41.2) 438 (46.0) Eridotrypa mutabilis 8 (6.2) 25 (8.6) 26 (8.5) 14 (6.3) 73 (7.7) Parvohallopora pulchella 3 (2.3) 13 (4.4) — 13 (5.8) 30 (3.2) Heterotrypa subtrentonensis 7 (5.4) 16 (5.5) 16 (5.2) 21 (9.4) 60 (6.3) Stigmatella distinctaspinosa 3 (2.3) 6 (2.0) 9 (2.9) 4 (1.8) 225223) Tarphophragma multitabulata 4 (3.1) 16 (5.5) 12 (3.9) 14 (6.3) 50 (5.2) H. flabellaris var. spinifera — 10 (3.4) 72:3) Ueei)) 25 (2.6) Mesotrypa angularis A 13 (4.4) 3 (1.0) 3 (1.3) 19 (2.0) Parvohallopora granda A 23 (7.9) = 20 (9.0) 44 (4.6) Anaphragma hermitagensis 2 (1.5) S17) 16 (5.2) — 23 (2.4) Heterotrypa magnopora A 12 (4.1) 3 (1.0) 10 (4.5) 25 (2.6) Peronopora mundula A = = = = Homotrypa tuberculata 7 (5.4) 6 (2.0) 5 (1.6) 7 (3.1) 25 (2.6) Tarphophragma ampla 3 (2.3) = 5 (1.6) A —_ Homotrypa subramosa 3 (2.3) —_— 5 (1.6) = = Peronopora weirae A — — Mae) _ Homotrypa minnesotensis 7 (5.4) — 11 (3.6) a= 19 (2.0) Acantholaminatus typicus — _- _— A — H. praenuntia var. echinata = = = = i, Homotrypa similis A = = = Other species 7 (5.4) H5iSel) S722) 10 (4.5) 69 (7.2) Column Totals 130 292 306 223 951 Table 5.—Continued. MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH WB HCM Species present (ft) 2-32 3-11 (m) (0.69.8) (0.9-3.4) Bythopora dendrina 44 (19.7) 68 (53.5) Eridotrypa mutabilis _ A Parvohallopora pulchella 61 (27.3) 3 (2.4) Heterotrypa subtrentonensis 25 (11.2) 6 (4.7) Stigmatella distinctaspinosa 9 (4.0) 765) Tarphophragma multitabulata A A H. flabellaris var. spinifera ae — Mesotrypa angularis — A Parvohallopora granda 3 (1.3) = Anaphragma hermitagensis 10 (4.5) TABS) Heterotrypa magnopora 5 (2.2) A Peronopora mundula 6 (2.7) A Homotrypa tuberculata A 5 (3.9) Tarphophragma ampla — 9 (7.1) Homotrypa subramosa 11 (4.9) 9 (7.1) Peronopora weirae 4 (1.8) = Homotrypa minnesotensis A A Acantholaminatus typicus 8 (3.6) 2 (1.6) H. praenuntia var. echinata 9 (4.0) 2 (1.6) Homotrypa similis A A Other species 22 (9.9) 6 (4.7) Column Totals 223 127 species (13 genera) (not including Constellaria con- sidered here to be a cystoporate) from the Blackriveran and Trentonian strata of New York State. Within the Rockland to Shoreham Formations (approximately the lower half of the Trentonian Stage of Twenhofel et al., 1954), there are 11 species and 10 genera of trepos- tomes of which only three species are common to the Hermitage of the present study area, namely Praso- pora falesi (as P. simulatrix), Eridotrypa mutabilis, and Bythopora dendrina. Twenhofel (1954) considered the Kirkfield to Shoreham Formations to be roughly time-equivalent to the Hermitage of the Central Basin of Tennessee. Fritz (1957) studied the trepostome fauna from the Ottawa Formation of eastern Canada (Pamelia to Co- bourg Formations: Black River through Trentonian of Twenhofel et al., 1954; the Cobourg is now considered to be Cincinnatian in age by Sweet and Bergstrom, Table 6.—Relative abundances of common trepostome species found within Bryozoan Assemblage Two. See Table 5 for explanation of column headings and abbreviations used. NL IV CB CB Total (ft) 43-51 50-62 138-145 CB Species present (m) (13.1-15.5) (15.2-18.9) (42.1—44.2) Total Bythopora dendrina 321 (30.9) 194 (27.3) 67 (34.2) 60 (44.8) 127 (38.5) Eridotrypa mutabilis 177 (17.0) 148 (20.8) 20 (10.2) 9 (6.7) 29 (8.8) Anaphragma hermitagensis 167 (16.1) 136 (19.2) 19 (9.7) 12 (9.0) 31 (9.4) Mesotrypa angularis 94 (9.0) 71 (10.0) 13 (6.6) 10 (7.5) 23 (7.0) Prasopora falesi 60 (5.8) 42 (5.9) 13 (6.6) 36:7) 18 (5.4) Tarphophragma ampla 35 (3.4) 28 (3.9) 6 (3.1) — 7 (2.1) Heterotrypa subtrentonensis 29 (2.8) = 17 (8.7) 6 (4.5) 23 (7.0) Tarphophragma multitabulata 14 (1.3) — 5 (2.6) 4 (3.0) 9 (2.7) Homotrypa minnesotensis 14 (1.3) 9 (2.7) A 5 (3.7) S){(les))) H. praenuntia var. simplex 10 (1.0) — — 4 (3.0) 4 (1.2) Cyphotrypa acervulosa 10 (1.0) — — 4 (3.0) 4 (1.2) Homotrypa subramosa — — 7 (3.6) DiGeS) 9 (2.7) Homotrypa tabulata _— A 6 (3.1) A 6 (1.8) Other species 94 (9.0) 59 (8.3) 23 (11.7) 12 (9.0) 35 (10.6) Column Totals 1040 710 196 134 330 N i) BULLETIN 353 LATERAL RELATIONSHIPS OF BRYOZOAN ASSEMBLAGES [III] Assemblage One HOWARD CEMETERY WILSON BRANCH GMB Assemblage Two CHAMBERLAIN (7_j Assemblage Three NORRIS LAKE BRANCH IV aes. eZ mail T-3 BENTONITE Text-figure 6.—Lateral relationships of Bryozoan Assemblages 1, 2, and 3 across the East-Central Tennessee study area. Positioning of the four measured sections approximately reflects their relative distances of geographic separation. Dotted lines separating Biostratigraphic Zones A, B, and C are suggested to represent time-equivalent horizons (see section on Biostratigraphic Utility of Bryozoan Distributions, p. 24). 1971, among others). Of the 48 species described (51 taxa including varieties), 20 occur within the Rockland and/or Hull Formations (lower half of the Trentonian Stage of Twenhofel ef al., 1954) with four species in common with the Hermitage of the present study area. These include Tarphophragma multitabulata (as Hal- lopora multitabulata), Prasopora falesi (as Prasopora simulatrix var. orientalis), Hemiphragma ottawaensis, and cf. Homotrypa similis. Thirty species are found within the interval spanned by the Rockland, Hull, and Sherman Falls Formations (lower three-fourths of Twenhofel et al.’s, 1954, Trentonian Stage) with five species common to the Hermitage of Tennessee (the four species directly above in addition to Heterotrypa praenuntia var. echinata as Dekayella praenuntia var. echinata). Of these five species, Prasopora falesi and Tarphophragma multitabulata also occur in the Tar- phophragma multitabulata zone of Karklins (1984). Ulrich (1893) noted the occurrences of many tre- postome bryozoan species from the Trenton Shales (= Table 7.—Relative abundances of common trepostome species found within Bryozoan Assemblage Three. See Table 5 for explanation of column headings and abbreviations used. NL IV Total (ft) 93-117 Species present (m) (28.4-35.7) Batostomella subgracilis 655 (29.9) 506 (37.2) Bythopora dendrina 359 (16.4) 140 (10.3) H. flabellaris var. spinifera 271 (12.4) 126 (9.3) P. granda var. inflata 159 (7.3) 144 (10.6) Parvohallopora granda 148 (6.7) 116 (8.5) Homotrypa subramosa 64 (2.9) Parvohallopora pulchella e257) 30 (2.2) Tarphophragma multitabulata 52 (2.4) 40 (2.9) H. praenuntia var. echinata 33) (1-5) 20 (1.5) Acantholaminatus typicus 33 (1.5) = Heterotrypa magnopora 31 (1.4) 17 (1.2) Homotrypa tuberculata 26 (1.2) = Mesotrypa angularis 21 (1.0) — Other species 280 (12.8) 197 (14.5) Column Totals 2191 1360 CB WB HCM 81-85 38-44 18, 38-43 (24.7-25.9) (11.6-13.4) (5.5, 11.6—13.1) 47 (26.2) 51 (36.0) S1iGi333)) 44 (24.6) 97 (19.0) 78 (20.4) 2117) 16 (5.9) 108 (28.1) 4 (2.2) 11 (4.1) — 14 (7.8) 6 (2.2) 12 (3.1) 5 (2.8) 32 (11.9) 22 (5.7) 2 (GLE) 9 (3.3) 18 (4.7) 11 (6.1) = A 5 (2.8) 8 (3.0) A A 7 (2.6) 21 (5.5) 3 (1.7) 10 (2.6) 2 (1.1) A 21 (5.5) 7 (3.9) = = 14 (7.8) 29 (10.8) 40 (10.4) 179 269 383 23 MARINTSCH MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE uone} -13e aye1apoul s1potied UM JOYS 19yBM 19INE (q) A310uq MOT JOYS MOTTeYS— ouueu uadQ— jdams JuounD— AB19U9-1H Jayem jatnb Ajaies1apoyw (A) Jfoys uado pajeyide Ajayeiapoyy (qq) ASiauq aeIpauaquy (snoaor]isie aiayM Aqyeroad -Sd) sjeuUIN[OS uROZOyRU[ad pure suaosagasoul DUIAMIOYIUAYY (AA) Syisaf DjyjauDuUyjoG BWos (A) pyjaunoad siyjsoulqd ‘ds npjakqaamog sisuasppiuiay Duinbsauypy syusaf pjjaupuyjog (A) DAJSOAIAANIAA DALASOSKZ s[euunyjoo urozoyewyad SUAISAGAdIUL DULAAJOYIUAYY (A) sjeuuinjos uvozoyeuyad sprouawoydons ‘ds ppjakqiamos sisuaspjiuiiay Duinbsauifpy asso] syisaf Djjaubuyog (A) JUDUIUOIAUA s|Issojosorul paieioosse AyUOWIWIO jnduy snosoryIs1y YSIH 0} aeIopoyy uO sayoVM (AA) (Quoysyordg Ajreau) QUOISayOeAMA, Jassay] YM (QUO}sSa -yor Apreou) auojsyoeg (q) (I asv[quiassy ueY) sso] ‘| asv[quiassy uPY) 1d}k013) a[qeuea jndur snoaory]Is1Vv auojysyord (4) ind -UI SnOsdoeT [ITY BI] 01 ON uO sayOeA (AA) auojsyord 19 -UBQIO JASS2] YIM (QUO}Sa -yorsy Apirau) auoisyorg (A) adAjoyiy juRUTWOGg pyjayojnd vaodo]jpyoaivd psowpiqns DdKAJOUWOH ppuvis. viodo]]DYyOAid DIDYful “eA ppuvsés viodo]]DYOAIDd paafiuids ‘ea supjjaqoy vdXujowoy pulipuap piodoyiig SIPLIDASGNS YI]JIUWOISOIDG SISUGUOIUAAIGNS DdKAJOII1A HY pidup puspiydoydiv ], isajpf pAodosvig sLipjnsup pdXuosap sisuaspyiuiiay vusviydouy syiqvinu pdXuopiug pulipuap viodoyikg ppuvis piodo]]DYyouiwd supjnsuv vdXosap paafiuids ‘rea siupjjaqoyf vd\jowoy pipjngviyjnu puspiydoydav | psouldspjouysip DjJAIDUSUS SISUBUOJUIAIGNS DdKAJOIIIA HY pyayojnd vsodojjpyoaivg syiqovinu vd&ujopiq pulipuap vaodoyiKg satoads awojsodan juRuTUOg “[quiasse urozoAig ‘(Ala\9WIaD preMO} pur yourig UOSTIA) 19M ALIS Wolsey = (AA) ‘(YOuRIG urepaquiey) pur AJ OXe] SLUON) 19g FYLWIS wiaseq = (q) ‘uoNnIsodap Jo sjusWUOMAUD pur ‘s[IssOJosORUT payeIoosse ‘adAjoyI] 0} sade|quiassy uvozoAag Jo sdrysuonryjas Jo ArewuUNg—g aqeL 24 BULLETIN 353 the Decorah Shales of other authors), Galena Shales and Limestones (Trenton) of Minnesota and their pres- ence in some time-equivalent strata from Kentucky, Tennessee, Iowa, Wisconsin, and Canada. These in- clude Prasopora falesi (as P. simulatrix and P. simu- latrix var. orientalis), Peronopora mundula (as Hom- otrypella mundula), Homotrypa similis, Homotrypa tuberculata, Homotrypa subramosa, Homotrypa cal- losa, Homotrypa minnesotensis, Batostomella subgra- cilis, (as Homotrypella (?) subgracilis), Eridotrypa mutabilis, Cyphotrypa acervulosa (as Leptotrypa ac- ervulosa), Heterotrypa praenuntia var. simplex (as De- kayella praenuntia var. simplex), Heterotrypa praen- untia var. echinata (as Dekayella praenuntia vat. echinata), Hemiphragma ottawaensis, (as Hemiphrag- ma ottawense), Parvohallopora pulchella (as Callo- pora pulchella), Tarphophragma ampla (as Callopora ampla), and Tarphophragma multitabulata (as Callo- pora multitabulata). Though less restricted in scope compared with other authors, Ulrich’s work is included here due to the presence of so many common species. Five species found in the present study area are thought to have possibly originated in Blackriveran time. These include Tarphophragma multitabulata (= Hallopora multitabulata) of Fritz (1957) (Pamelia Beds of the Ottawa Formation of Canada), Hemi- phragma ottawaense of Fritz (1957) (Pamelia Beds) and Foord (1883) (= Batostoma ottawaense from the Black River Formation of Canada), Prasopora falesi (= P. simulatrix var. orientalis) of Fritz (Pamelia Beds), cf. Homotrypa similis of Fritz, 1957 (Pamelia Beds), and possibly Heterotrypa praenuntia var. echin- ata (= Dekayella praenuntia var. echinata) of Loe- blich (1942) (Bromide Formation of Oklahoma). The 11 newly designated species and two new va- rieties described herein are suggested to be endemic to the study area. Nearly all of the remaining species are noted by Ulrich (1893) and other authors to first occur for the most part within the Trenton Shales (= Decorah Fm.), Galena Shales, lower Lexington Limestone, Rockland Formation, and Shales of the Trenton Group. Two of these species were formerly restricted to the Upper Ordovician (?Heterotrypa subramosa of Ut- gaard and Perry, 1964 and Ulrich, 1879, from the Richmondian of Indiana and Ohio; and Homotrypa fla- bellaris var. spinifera of Bassler, 1903 and Cumings, 1908, from the Cincinnatian). The lack of information as to the precise stratigraphic horizon of collection for previously described species as well as the absence of detailed conodont distributions for the Tennessee study area preclude any inferences as to the first temporal occurrences and hence speciation sites. BIOSTRATIGRAPHIC UTILITY OF BRYOZOAN DISTRIBUTIONS FROM TENNESSEE STUDY AREA The stratigraphic distribution of taxa between the two eastern sections, Norris Lake [TV and Chamberlain Branch, is not dissimilar in relative order of appear- ance. Of 27 taxa in common to both sections, 20 have a similar order of stratigraphic appearance (the corre- lation coefficient for a bivariate plot comparing the first stratigraphic occurrences of these taxa is r = 0.85). If Heterotrypa rugosa is not taken into account (this species occurs at a single disproportionately high stratigraphic level at Chamberlain Branch compared to Norris Lake IV) the remaining 19 taxa have a corre- lation coefficient of r = 0.96 (see Sweet, 1984, for more information on the correlation method used here- in). Some generalizations can be made concerning the overall stratigraphic sequence within these eastern sec- tions. Each section (Norris Lake [TV and Chamberlain Branch) is divided into five units (labelled I through V) whose boundaries are arbitrarily defined by the present author to be the most useful in correlation be- tween the sections (Text-figs. 7-10). Each unit (interval, zone) is composed of several diagnostic taxa (called “‘characteristic members”’) which make their initial stratigraphic appearances somewhere within the interval. Its lower boundary is defined as the lowermost appearance of any one taxon making up the unit, while the upper boundary is de- lineated by the lower boundary of the succeeding in- terval. Unit I, for example, is marked by the presence (at each of the two sections) of Bythopora dendrina, Stigmatella distinctaspinosa, Homotrypa subramosa, Eridotrypa mutabilis, Anaphragma hermitagensis and Homotrypa minnesotensis. This unit is followed by one (Unit II) defined by the first appearances of Hom- otrypa similis, Parvohallopora pulchella, and Tarpho- phragma ampla. Unit Ill follows with Prasopora fa- lesi, Batostomella subgracilis, Cyphotrypa acervulosa, and possibly Heterotrypa magnopora (this latter spe- cies actually occurs in uppermost Unit II at Chamber- lain Branch but occupies a position at the Unit II-III boundary at the other three study localities). Unit IV contains the first appearances of Peronopora weirae and Parvohallopora granda. Unit V is denoted by the occurrences of Parvohallopora granda var. inflata, ?Heterotrypa subramosa, and Heterotrypa rugosa. Since in most cases, ranges of individual taxa span over half the section and commonly terminate near the top of the section (see especially Norris Lake IV, Text- fig. 7), the development of range zones or concurrent range zones to create a refined biostratigraphy is pro- hibited. Units I through IV are, in a sense, assemblage zones with the appearances of new taxa in each zone MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH PES) NORRIS LAKE IV 2) S pbes Goes > Gi i oo Ss oe eS ee Oe Text-figure 8. to boundaries of Bryozoan Assemblages 1, symbols used. species only occurring at Chamberlain Branch), and Tarphophragma ampla (within Unit II to the east) ex- clusive of species appearing for the first time higher in the section (defining Units B and C). Unit B is marked by the initial appearances of Batostomella sub- gracilis, Parvohallopora granda, Peronopora weirae, and possibly Heterotrypa magnopora (occurs in up- permost Unit A at Chamberlain Branch, but in Unit B at all other sections). Parvohallopora granda var. in- flata is found in the uppermost strata at Wilson Branch lOx= Range chart of trepostome bryozoan species occurring at the Chamberlain Branch and the relationship of this distribution and 3 and Biostratigraphic Units I-V and A-C. See Text-figure 7 for further explanation of and is the only representative of Unit V to occur to the west and hence is assigned to Unit C in order to point out this position high in each section. These spe- cies defining Units A—C are the basis for forming what is believed to be the best defined and consistently de- veloped correlatable units presently available among all sections of the study area. Inconsistencies in the relative distributions of taxa among the study localities are possibly due in part to the vagaries of sampling (e.g., differences in sample 27 MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH WILSON BRANCH Text-figure 9.—Range chart of trepostome bryozoan species occurring at the Wilson Branch and the relationship of this distribution to boundaries of Bryozoan Assembl used. ages 1, 2, and 3 and Biostratigraphic Units I-V and A-C. See Text-figure 7 for further explanation of symbols HOWARD CEMETERY postome bryozoan species occurring at the Howard Cemetery and the relationship of this distribution to —Range chart of tre boundaries of Bryozoan Assemblag Text-figure 10. ymbols Jnits I-V and A-C. See Text-figure 7 for further explanation of s es 1, 2, and 3 and Biostratigraphic used 28 BULLETIN 353 size, or sampling only limited portions of the ancient sea bottom), the local absence of species both geo- graphically and stratigraphically, and the effects of lo- cal facies on species presence and/or abundance (.e., appearances which are ecologically controlled). Con- sequently, the relative stratigraphic distributions for taxa found in outcrops of limited thicknesses, such as those examined in this report, are not unexpectedly somewhat variable. Therefore the subdivisions of the stratigraphic display into more numerous correlatable subunits than presented herein is prohibited. It is notable, particularly at Norris Lake IV (Text- fig. 7), that the boundaries of several biostratigraphic units are correlatable with the appearances of partic- ular bryozoan assemblages (which themselves are pos- sibly tied in to local facies; see sections on Environ- mental Interpretations of Bryozoan Assemblages, pp. 13-15). Units I and II are largely coincident with Bryozoan Assemblage One. The lower boundary of Bryozoan Assemblage Two coincides with the ap- pearance of Unit III, and Bryozoan Assemblage Three is stratigraphically equivalent to Unit V. In general, for all sections in the study area, species defining the low- er boundaries of biostratigraphic zones are very minor constituents (<2%) of their associated assemblages. For example, the base of Unit IV is coincident with the reappearance of Bryozoan Assemblage One. De- fining the base of Unit IV in the eastern sections are the initial stratigraphic appearances of Peronopora weirae and Parvohallopora granda. Each occurs in abundances of less than two percent reflecting only minor taxa added to the more common taxonomic components of Bryozoan Assemblage One found low- er in the section. Elsewhere, due in large part to the compact distribution of Units A and B (Units I through IV) over a much thinner stratigraphic sequence, the relationship of biostratigraphic borders to bryozoan as- semblage boundaries is less clear. McKinney (1971a, p. 195), studying the distribution of trepostome bryozoans within about a 200 ft (61 m) interval of the lower Chickamauga Group in Alabama, concluded that “‘although occurrences and relative abundances of trepostomes have a recognizable verti- cal zonation, the zonation may be due as much or more to facies control as to sequential evolutionary devel- opment.”” The majority of his trepostome species, however, appear in two or more of his three major lithologic units, with abundance changes in individual taxa being a notable characteristic across lithic unit boundaries. It is noteworthy that in the present study area, in almost all instances, once a species appears in a section, it persists stratigraphically through the over- lying bryozoan assemblages and the associated array of heterogeneous carbonate lithologies (though its rel- ative abundance may vary). This is an important point when considering the control of lithofacies on the bio- stratigraphic display for it suggests a certain robustness of bryozoan taxa for purposes of correlation. CONCLUSIONS (1) The trepostome bryozoan fauna forms a numer- ically dominant fossil group in the Hermitage For- mation of East-Central Tennessee. Here it is composed of 36 species-group taxa (encompassing 17 genera and 33 species (including 5 varieties). (2) One new genus, 11 new species, and two new varieties are designated. The new genus, Acantholam- inatus, consists of two species—A. typicus and A. mul- tistylus. Other new species include Parvohallopora granda, Anaphragma hermitagensis, Peronopora wei- rae, Heterotrypa magnopora, H. subtrentonensis, H. exovaria, H. rugosa, Stigmatella distinctaspinosa, and Homotrypa tabulata. New varieties include Batosto- mella_ subgracilis var. robusta and Parvohallopora granda vat. inflata. Taxa previously described and found within the present study area include Bythopora dendrina, Batos- tomella subgracilis, Prasopora falesi, Eridotrypa mu- tabilis, Mesotrypa angularis, Parvohallopora pulchel- la, Homotrypa minnesotensis, H. flabellaris var. spi- nifera, H. subramosa, H. callosa, H. similis, H. tub- erculata, ?Heterotrypa subramosa, Heterotrypa praenuntia var. simplex, H. praenuntia var. echinata, Cyphotrypa acervulosa, Peronopora mundula, Tar- phophragma ampla, T. multitabulata, and Hemiphrag- ma ottawaensis. Three species were not assigned a trivial name and are identified herein as Monticulipora sp. A, Homotry- pa sp. A, and Mesotrypa sp. A. (3) Of the bryozoan taxa previously described, three or possibly four are known to have originated in the Blackriveran Stage. Other species first appeared in the lowermost Trenton but determination as to their precise stratigraphic first occurrences (as compared to the Hermitage and each other) are not yet determinable based on the detail of current biostratigraphic relation- ships and/or published locality information. For two species, the present study documents their lowest oc- currence in the stratigraphic record, having previously been restricted to the Upper Ordovician. (4) The Hermitage Formation has several trepos- tome taxa whose morphological limits are most diffi- cult to discern due to the presence of nearly continuous gradations in character states. For example, the varie- ties Parvohallopora granda var. inflata and Batosto- mella subgracilis var. robusta differ from the non-va- rietal forms primarily in the development of the exo- zone (e.g., length of the exozone, and wall thickness) MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH 29 and raise questions as to possible environmental ef- fects on the phenotype. Criteria employed to delimit morphological boundaries between taxa of some spe- cies-couplets (e.g., Tarphophragma ampla > Tarpho- phragma multitabulata; Bythopora dendrina > Batos- tomella subgracilis; Parvohallopora pulchella > Par- vohallopora granda) are often subtle because the range in morphologies between taxa of each couplet is largely a continuous gradient in zoarial form. Other questions concerning phenotypic variability are illustrated by such species as Homotrypa flabellaris var. spinifera whose specimens in the present study area express only a limited portion of the morphologic variability exhibited elsewhere for this taxon. (5) Groups of numerically dominant trepostome species were observed to occur in time and space and have been referred to herein as Bryozoan Assemblages One, Two, and Three. For sections throughout the study area as a whole, Assemblage One is character- ized by Bythopora dendrina (39% of the trepostome colonies present in the assemblage), Eridotrypa mu- tabilis (11%), Parvohallopora pulchella (10%), Het- erotrypa subtrentonensis (4%), Stigmatella distinctas- pinosa (4%), Tarphophragma multitabulata (3%), and Homotrypa flabellaris var. spinifera (3%). Assemblage Two is composed of Bythopora dendrina (31%), Eri- dotrypa mutabilis (17%), Anaphragma hermitagensis (16%), Mesotrypa angularis (9%), Prasopora falesi (6%), and Tarphophragma ampla (3%). Assemblage Three is made up of Batostomella subgracilis (30%), Bythopora dendrina (16%), Homotrypa flabellaris vat. spinifera (12%), Parvohallopora granda var. inflata (7%), and Parvohallopora granda (7%). Other species occur as less than 3%. (6) Assemblage One is associated with a moderate- ly agitated shelf environment to the east at the Norris Lake and Chamberlain Branch sections as suggested by the presence of packstones, large allochems, and scattered coquinite beds. To the west, wackestones with minor packstone interbeds indicate a somewhat quieter setting with intermittent turbulence. Assem- blage Two is found only within the two eastern sec- tions. It represents the highest energy environment (also open marine shallow shelf) found in the study area, being predominantly composed of packstones with some cross-bedding, size-sorted shelly beds and the most massive trepostome zoaria. Assemblage Three, present in all four sections, contains large amounts of relatively argillaceous muddy wackestones and is considered herein to have occupied the lowest energy environment of the study area. Pulses of mod- erate agitation in the eastern sections are suggested by the periodic appearance of a packstone fabric. (7) A biostratigraphic comparison of the species contained in the Hermitage Formation with other Mid- dle Ordovician assemblages from Kentucky, New York, and the Upper Mississippi Valley shows a rela- tively close similarity in species composition to Kark- lins’ (1984) trepostome fauna of the lower 150 feet (45.7 m) of the Lexington Limestone (especially in the two eastern sections at Norris Lake and Chamberlain Branch) suggesting an equivalence of the Hermitage Formation to part of his Tarphophragma multitabulata Zone of Kirkfieldian to early Shermanian age. (8) Biostratigraphic subdivisions within the Her- mitage of the present study area are based on the first appearances of selected diagnostic species and their co-occurrences within a stratigraphic interval exclu- sive of species characteristic of the succeeding over- lying zones. This allows the Hermitage to be divided into three loosely defined biostratigraphic zones (five zones within the eastern sections), the boundaries of which are possibly influenced by subtle variations of local lithofacies. INTRODUCTION TO SYSTEMATIC PALEONTOLOGY TAXONOMIC CONSIDERATIONS A trepostome bryozoan colony consists primarily of a number of physically connected, asexually budded zooids and extrazooidal and multizooidal parts (the lat- ter two are parts of colonies grown outside of zooidal boundaries). Only the initially formed zooid (or zo- oids) of the colony are sexually produced. The geno- type within any one colony, then, is principally the same for each zooid. Any morphologic variation with- in the colony can be ascribed to four components of morphologic variability (Boardman et al., 1970). These are (1) Astogeny, or changes associated with the development in the sequence of asexual generations of zooids and extrazooecial parts (parts such as acan- thostyles, grown outside of zooecial boundaries), (2) Ontogeny, or changes associated with the development of individual zooecia, (3) Polymorphism, or distinct and discontinuous morphologic variations among zo- oids of any one colony at equivalent growth stages, and (4) Microenvironmental effects, or phenotypic variability within portions of a colony. Assuming, then, that the above sources of morpho- logic variability can be identified within each colony, the remaining variability among colonies of any pop- ulation should presumably reflect true genotypic dif- ferences among species members, and possibly any colony-wide phenotypic effects which can often be difficult to detect. Theoretically, the presence of such colony-wide effects may be inferred if the same type of morphologic variation is found elsewhere, in other 30 BULLETIN 353 colonies, as microenvironmental (portion of colony) differences, or if the variation in character state closely covaries with presumed environmental changes (gra- dients) (though they may be genetic; see, for example, Schopf and Dutton, 1976, who associated the clinal variation in avicularium size in a modern cheilostome bryozoan species with true genetic differences and not a covarying temperature gradient). Within the systematic descriptions of trepostome bryozoans and tables of quantitative data herein, at- tempts have been made to include in the identification of each species those independent characters (character states not partly determined by states of other char- acters) that presumably reflect genetic and not envi- ronmental control (see Boardman ef al., 1983, for a more comprehensive review of genetic and environ- mental control as well as approaches to taxonomic characters in bryozoans). These particularly include features grown within the inner epidermis and pro- tected by the body cavity from their immediate sur- roundings as compared to colony parts secreted by the external body wall such as the colony base (free- walled or double-walled stenolaemate Bryozoa of Borg, 1926). These will not only serve to truly char- acterize the species under examination, but also serve to increase the evolutionary faithfulness of any bio- logic classification. Independent characters used in the present study from which data have been tabulated include such measurements as autozooecial cavity diameter within non-macular and macular (= polymorphic) areas, acanthostyle diameter, and mesozooecial cavity diam- eter (see section on Key to Abbreviations Used (p. 33) for additional characters). Another common quantita- tive measurement generally accepted by workers and also used in the present study is the number of zooecia per square mm. In and of itself, this character is a non- independent one since it reflects the variation of two independent characters, namely autozooecial size as well as wall thickness. If it is taken to indicate the relative spacing of zooecia, however, it might then be considered to reflect an independent taxonomic char- acter (Boardman, 1983). Qualitative descriptions in- clude a host of characters (see the section on Descrip- tion Format; p. 32) such as shape of autozooecial ap- erture, wall microstructure, type of intrazooecial par- tition (e.g., cystiphragm, diaphragm), and presence of polymorphs and extrazooecial parts (e.g., mesozooecia and acanthostyles, respectively). A taxonomic char- acter involving more than one zooecium would be the geometric configuration of endozone zooecia. This budding pattern appears to be quite regular within many individual species, suggesting a relatively high degree of genetic control (McKinney, 1977; Board- man, 1983). All of the above characters have been commonly used or are increasingly being used as stan- dard taxonomic characters having evolutionary signif- icance by bryozoan workers in the delineation of their individual species. Certain characters used in descriptions of treposto- me species are commonly considered by workers to be relatively variable within colonies (i.e., generally more susceptible to short-time environmental effects). These include such features as diaphragm spacing, wall thickness, and diaphragm thickness since they are par- ticularly sensitive to variations in colony growth rate (either microenvironmmentally or colony-wide). These, however, are valid taxonomic characters, since the limits within which the states of a character can express direct environmental modification are assumed to be genetically controlled (Boardman, 1983). GLOSSARY OF TERMS USED IN MORPHOLOGIC DESCRIPTIONS ACANTHOPORE—Synonym of acanthostyle. ACANTHOSTYLE—Calcitic structure usually found between and parallel to zooecia and consisting of a clear non-laminated rod with surrounding concentric laminar sheaths that deflect zooecially inwards forming a cone-in-cone structure. AMALGAMATE WALL STRUCTURE—See com- ments under Zooecial Boundary. ASTOGENETIC CHANGES—Changes in morphol- ogy of a colony associated with asexual budding of new zooecia (rather than variation associated with the development of a single zooid). AUTOZOOECIUM—The most common type of zooe- cium found in trepostomes, considered to be the skeletal part of normal feeding zooid. AXIAL REGION—Zone encompassed within endo- zone. AXIAL DIAPHRAGMS—Diaphragms present within endozone. CRENULATE WALLS—Walls that are extremely ir- regular along their length. CYSTIPHRAGM— Distinctly cystose skeletal partition formed by convex-outwards extension from zooecial wall into adjacent zooecial cavity with reattachment of recurved surface zooecially inwards to a subjacent diaphragm, another cystiphragm, or same zooecial wall. Cystiphragm will partly or entirely wrap around the periphery of zooecial chamber. CYSTOSE (CYSTOIDAL) DIAPHRAGM—A dia- phragm curved slightly convex outwards, extending only part way across zooecial tube and in contact with a lower diaphragm. DIAPHRAGM-— Skeletal partition extending across a zooecial (autozooecial or mesozooecial) cavity. It MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH 31 can be flat, curved convex zooecially inwards or outwards, or wavy. In addition, it can be perpendic- ular (transverse) to zooecial walls, or inclined (oblique). DIAPHRAGM-WALL UNIT—A distinct skeletal unit consisting of a diaphragm and continuous part of the wall laminae, the latter which merges into the main portion of the zooecial wall after a short dis- tance. DISTAL DIRECTION—Principal growth direction of a colony away from founding zooid(s). ENCRUSTING COLONY—Colony whereby all or most zooecia are attached to a foreign object by their basal walls forming a continuous encrusting skeleton adhering to the substrate. ENDACANTHOPORE—Synonym of endacantho- style. ENDACANTHOSTYLE—An acanthostyle found in the endozone. ENDOSTYLE—Synonym of acanthostyle. ENDOZONE—Aggregation of inner zooecial tubes found parallel or nearly so to zoarial axis (or distal growth direction) in branches of ramose forms and are zooecially proximal (basal) in encrusting forms. Walls are characteristically thin, diaphragms, cysti- phragms and other associated skeletal parts are usu- ally absent or rare. ENDOZONAL/EXOZONAL TRANSITION—The area along a zooecial tube whereby endozonal skel- etal parts begin to attain those features most closely associated with the exozone. These generally in- clude thickening of zooecial walls, an accelerated bending of tubes from an orientation more closely parallel to colony growth direction to one more closely perpendicular to colony surface and colony growth direction, and the acquisition of increased intrazooecial hard parts. EVEN-SIDED WALLS—Zooecial walls whose sides are straight (planar), and parallel. EXOZONE—Outer parts of zooecia that extend from the colony surface to the endozonal/exozonal tran- sition. Intersection with colony surface (surface an- gle) is commonly at or nearly at 90° but sometimes is less. Walls are thicker than for endozone, and in- trazooecial skeletal parts, primarily diaphragms, are nearly always present. Most mesozooecia and acan- thostyles are similarly associated with the exozone. GRANULAR WALL STRUCTURE—Wall structure that is not defined by laminae, but instead is appar- ently structureless and amorphous (but still appears translucent rather than transparent or clear). GROWTH SURFACE—That part of the outermost (i.e. external) zoarial surface presumed to be under- going growth (due to secretion of skeletal material by soft parts) at any particular instant in the asto- genetic development of the colony. HEMIPHRAGM—Shelflike projection extending per- pendicularly from zooecial wall into chamber. IMMATURE REGION—Synonym for endozone. INCLINED DIAPHRAGM—Diaphragm not perpen- dicular to zooecial axis. INCOMPLETE DIAPHRAGM—An inclined, rela- tively flat, diaphragm extending only part way across zooecial tube and in contact with a lower diaphragm. INFLECTING ACANTHOSTYLE—Acanthostyle whose laminar sheath inflects into surounding zooe- cial cavity (i.e., reverses the convexity of the zooe- cial cavity outline). Some inflecting styles are offset. INTEGRATE WALL STRUCTURE—See comments under Zooecial Boundary. IRREGULAR WALLS—Zooecial walls that are not straight, but are wavy along their length. LAMINAR SHEATH—Part of acanthostyle consisting of concentric laminae in a cone-in-cone structure pointed towards colony surface and surrounding a centrally located non-laminated clear calcite core (=lumen). LONGITUDINAL SECTION—Section cut through colony which is parallel to zooecial axes, that is, parallel to the growth direction of individual zooe- cla. LUMEN—Clear, non-laminated calcitic rod of an acanthostyle. MACULAE—Clusters on zoarial surface consisting of varying combinations of zooecial polymorphs (me- gazooecia, mesozooecia), autozooecia, extrazooidal skeletal material (including acanthostyles), and thickened zooecial walls. Maculae commonly form protuberances raised above colony surface (monti- cules of some authors), sometimes flush with sur- face, or depressed. MASSIVE COLON Y—Colony of irregular shape. As for encrusting colonies, some zooecia bud from ba- sal walls, as for ramose colonies, some zooecia bud from vertical walls of surrounding zooids. MATURE REGION—Synonym for exozone. MEDIAN LAYER—In some bryozoans, a distinctive colony wall parallel to zoarial growth direction from which zooids bud on either side forming a bifoliate pattern. Common in some species of Peronopora. MEGAZOOECIA—Zooecia distinctively larger than surrounding autozooecia. Found commonly in mac- ulae and within the inner endozone of some species. MESOPORES—Synonym of Mesozooecia. MESOZOOECIA—Polymorphic zooecial parts nearly always found in the exozone, parallel to and of gen- erally smaller diameter than surrounding autozooe- 32 BULLETIN 353 cia, closely tabulated throughout, and with dia- phragms commonly thicker than for autozooecia (= mesopores of some authors). MONILIFORM—Zooecial walls found in the endo- zone that periodically split and rejoin to form one or more hollow beads along their lengths. MONTICULES—See definition of Maculae. MURAL LACUNAE—Small equidimensional irreg- ularities or spaces in skeletal laminae. They often appear as faint ‘‘acanthostyle-like’’ markings seen especially well in tangential sections. OFFSET ACANTHOSTYLE—Acanthostyle whose position between adjacent zooecia is non-symmet- rical. Some offset acanthostyles will inflect. ONTOGENETIC CHANGES—Changes associated with the development of individual zooids (and ex- trazooidal parts such as styles). Ontogenetic varia- tion within a colony, then, is the sum total variation associated with developmental states of multitudi- nous individual zooids. OVERLAPPING DIAPHRAGM—Synonym of In- complete Diaphragm. PETALOID ARRANGEMENT—A term commonly used in describing the petal-like arrangement of au- tozooecia around a centrally located acanthostyle. POLY MORPHISM—Distinctive variation in mor- phology among zooecia of a single colony at the same developmental stage (e.g. mesozooecia and megazooecia). PROXIMAL DIRECTION—Opposite to distal, direc- tion towards founding zooid(s) of a colony. RAMOSE COLONY—Colony with distinct branches, usually circular (in trepostomes) in transverse sec- tion, with nearly all zooecia formed by budding from vertical walls of other zooids. STYLE—Synonym of acanthostyle. SURFACE ANGLE—The angle at which zooecia in- tersect the colony surface. TANGENTIAL SECTION—Section cut parallel to and just below the colony surface. In this type of section, autozooecia, mesozooecia, and acantho- styles will usually be cut transversely or nearly so (if they are inclined) to their axes (or growth direc- tions). TRANSVERSE SECTION—Section cut transverse to growth direction of zoarium (entire colony). In a section of this type, endozonal zooecia will be cut normal to their axes (growth direction). U-SHAPED WALL LAMINAE—As viewed in lon- gitudinal section, concentrically overlapping smoothly curving laminae oriented convex outwards in the direction of the colony surface and composed of the adjoining ends of contiguous zooecial walls (see also, Zooecial Boundary). V-SHAPED WALL LAMINAE—As viewed in lon- gitudinal section, concentrically overlapping cone- shaped laminae oriented with apices pointed out- wards in the direction of the colony surface. Apices mark the contact of zooecial walls from contiguous zooecia (see also, Zooecial Boundary). ZOARIUM—-Skeleton of bryozoan colony. ZOOECIAL BEND—A distinctive bend in a zooe- cium toward the colony surface and found generally at the endozonal/exozonal transition or in the lower exozone. ZOOECIAL BOUNDARY— Vertical partition be- tween adjacent zooecia marking the abutment of the respective contiguous zooecial walls. In some cases, laminae from each zooecium join to form smooth, evenly curved, seemingly continuous laminae (U-shaped) convex in the direction of zooecial growth (“‘amalgamate wall’ of some authors). In other cases, abutment is readily observable as an apparent distinctive bend (V-shaped), which often then appears as a dark central line dividing the mid- dle of the interzooecial wall (“‘integrate wall” struc- ture of some authors). ZOOECIAL CAVITY (CHAMBER, TUBE)—Void associated with zooecial skeleton occupied, or once occupied, by zooid. ZOOECIALLY INWARDS—Within a zooecium, the direction away from colony surface and towards point of initial budding. ZOOECIALLY OUTWARDS—Within a zooecium, the direction towards colony surface. ZOOECIAL WALL—Skeletal wall of zooid. ZOOECIUM—tThe skeletal part of a zoarium that houses a zooid (and previous generations of each zooid beginning with its inception through asexual reproduction). ZOOIDS—Basic soft-part morphologic units of a col- ony. Each is asexually budded, regenerative, phys- ically connected, and responsible for secretion of a skeletal zooecium. Zooids are very rarely preserved in the fossil record. DESCRIPTION FORMAT I. COLONY A. Zoarial Growth Habit (e.g., Ramose, Encrust- ing, Frondose, Massive, Bilaminate, etc.) B. Budding Origin (e.g., New zooecia initiated in outer endozone; secondarily in zone of zooe- cial bend) Il. ZOOECIA A. Zooecial shape in transverse section (of zooe- cial cavity outline and zooecial boundary in exozone and endozone) MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH B. Zooecial curvature from endozone to exozone (including zooecial bend) C. Surface angle D. Zooecial wall thickness—endozone and exo- zone (e.g., abrupt thickening in early exozone; maximum thickness in outer exozone); zooe- cial boundary (wall) microstructure in endo- zone and exozone E. Endozonal wall orientation (even; irregular; crenulate; parallel-sided); arrangement (e.g., megazooecia in center of endozone) FE Diaphragms (i) Orientation (e.g., planar, inclined, convex, concave, cystose, incomplete) (ii) Thickness variation (iil) Spatial variation (e.g., inequidistantly spaced, uniformly placed, etc.) G. Cystiphragms (i) Orientation (e.g., proximal or distal side of zooecia) (ii) Relationship to other cystiphragms and di- aphragms Ill. MESOZOOECIA A. Point of origin and termination B. Cavity outline in tangential section C. Longitudinal section shape (e.g., moniliform) D. Diaphragms (orientation, thickness, spatial distribution) E. Relative arrangement FE Turn into autozooecia (or vice-versa)? IV. ACANTHOSTYLES A. Point of origin and termination B. Size variation (of lumen and laminar sheaths) C. Configuration with respect to autozooecia and mesozooecia V. MACULAE A. Spacing B. Arrangement of zooecia, megazooecia, meso- zooecia, acanthostyles, cystiphragms, etc.) C. Presence as a surficial feature (raised, flat, de- pressed) D. Other variations distinctive to maculae (en- compassing variables noted above)—zooecial shapes, wall thicknesses, variations in dia- phragms and cystiphragms, etc. KEY TO ABBREVIATIONS USED IN TABLES OF QUANTITATIVE DATA 7 CAD | Raa Zooecial cavity diameter (autozooe- cium) MxZCD . Maximum zoocial cavity diameter (au- tozooecium) MnZCD . Minimum zoocial cavity diameter (au- tozooecium) 33 (mac) iene eee Within macular region of a colony (non-mac) .. Within non-macular region of a colony ENN psy As Zooecial wall thickness (autozooecium) TANI S556 Zooecia per square millimeter (zooe- cium counted if more than half its area is within the square millimeter) MCD Een: Mesozooecial cavity diameter MxMCD . Maximum mesozooecial cavity diame- ter MnMCD . Minimum mesozooecial cavity diame- ter ht. Fiseaeiee For mesozooecia whose shape approx- imates an equilateral triangle, ““ht” is the height of the triangle Wty eae incgics For mesozooecia whose shape approx- imates an equilateral triangle, ““wth” is the length of the line connecting the midpoint of any two sides AD! eens acts Acanthostyle diameter EDs piss hace Endacanthostyle diameter IEW Seocanes Laminar portion of acanthostyle IGT anooaboc Core or lumen of acanthostyle (GET) ocacocc Within the mature region of a colony (non-mat) ... Within the non-mature region of a col- ony ED) ch e.seaee Colony diameter (branch diameter) endoge-ee ore (measured) within the endozone @XO™ sSse ss (measured) within the exozone long) else (measured) within the longitudinal sec- tion SDittar cee Standard deviation of a particular mea- surement No.Meas . Number of measurements made within a particular colony No.Spec . Number of specimens (colonies) of any one species All measurements are in millimeters. In some lists of material examined, the following abbreviations are used: e = encrusting habit; r = ra- mose habit. SYSTEMATIC PALEONTOLOGY Phylum BRYOZOA Ehrenberg, 1831 Class STENOLAEMATA Borg, 1926 Order TREPOSTOMATA Ulrich, 1882 Family MONTICULIPORIDAE Nicholson, 1881 Genus PRASOPORA Nicholson and Etheridge, 1877 Type species.—Prasopora grayae Nicholson and Etheridge, 1877, p. 44—48. 34 BULLETIN 353 Prasopora falesi (James, 1884) Plate 1, Figures 1—2 Monticulipora falesi James, 1884, p. 138, pl. 7, figs. 2—2d. Prasopora simulatrix Ulrich, 1886, p. 85; Ulrich, 1893, p. 245-248, pl. 16, figs. 1-10; Ross, 1967a, p. 412-414, pl. 46, figs. 1, 2, 3, pl. 47, figs. 1, 3-5, pl. 49, figs. 5, 7, 9, pl. 50, figs. 1, 2. Prasopora simulatrix var. orientalis Ulrich, 1893, p. 246, pl. 16, figs. 1, 2, 6, 7; Fritz, 1957, p. 34-35, pl. 28, figs. 2, 3; Perry, 1962, p. 17-18, pl. 3, figs. 7, 8. Prasopora falesi (James). Bassler, 1906, p. 48, pl. 1, figs. 1—4; McFarlan, 1931, p. 95, pl. 2, figs. 11-12; Brown, 1965, p. 985— 986, pl. 112, figs. 3, 5—7; Marintsch, 1981, p. 957, pls. 1, 2; Karklins, 1984, p. 142-145, pls. 13, 14. Description.—Zoarial form varies from low discoi- dal to hemispherical. Zooecial cavity outlines rounded to subrounded. Each zooecium generally surrounded by and usually in contact with six others. Zooecia in- tersect colony surface at right angles. Walls thin and granular, even sided and parallel. In outermost portions of colony, or within colony along certain irregularly spaced colony-wide growth surfaces, walls thicken slightly and become laminar (cyclic rejuvenation). Di- aphragms present throughout zoarium and thin, fairly evenly spaced at one-half to one zooecial cavity di- ameter apart, subparallel and normal to zooecial walls, but some inclined and/or overlapping in places. Indi- vidual diaphragms commonly in contact with adjacent cystiphragms and zooecial wall; however, some at- tached to wall alone where cystiphragm lacking. Cys- tiphragms thin and continuously overlapping through- out most of zooecial lengths. Cystiphragms generally project halfway to slightly greater into the zooecial cavity in section though some extend considerably fur- ther. Cystiphragm shape is semi-circular to semi-ellip- tical in longitudinal section. Newly formed cysti- phragms usually overlap one-third to one-half of the one previously formed as measured parallel to the zo- oidal axis. Overlapping cystiphragms locally found without associated diaphragms over short segments of some zooecia. In tangential section, cystiphragms wrap around two-thirds to three-fourths of the zooecial pe- rimeter. Mesozooecia common throughout colony. Po- lygonal to subrounded cavity outlines. Diaphragms within mesozooecia evenly spaced, closely tabulated and slightly thicker than in autozooecia. Walls between diaphragms sometimes slightly convex outwards. Gen- erally, each of the six interzooecial voids surrounding any single zooecium is filled with at least one meso- zooecium. Along its length, a mesozooecium occa- sionally develops into an autozooecium and vice-ver- sa. Acanthostyles scattered throughout colony in those portions where thin, granular walls periodically thick- en and become laminar. Maculae present with mega- zooecia. Zooecia not necessarily contiguous, the space between them being filled by mesozooecia which are generally more common than in non-macular areas. On occasion, entire zooecium completely isolated by me- sozooecia. Maculae generally spaced about 4.0 to 4.5 mm from each other (measured between macular pe- ripheries). Measurements.—Measurements are summarized in Table 9. Remarks.—Prasopora falesi is characterized by rounded to subrounded cavity outlines of zooecia which are generally surrounded by six contiguous zooecia, the interzooecial voids of which are usually filled with closely tabulated mesozooecia, more com- mon mesozooecia and not necessarily contiguous au- tozooecia in macular areas, continuously overlapping cystiphragms which in longitudinal section are ob- served to be semi-circular to semi-elliptical, generally project halfway to slightly greater into zooecial tube, overlap one-third to one half of previously formed cys- tiphragms and in tangential section wrap around two- thirds to three-fourths of a zooecial perimeter, dia- phragms spaced at one-half to one zooecial cavity di- ameter apart and commonly in contact with adjacent cystiphragms, and acanthostyles that are scattered throughout colony where wall laminae thickened. Ulrich (1893) considered Prasopora simulatrix to have no acanthostyles. Specimens with morphologies comparable to P. simulatrix but possessing acantho- styles were assigned to P. falesi by several authors. Marintsch (1981) reexamined type material of P. si- mulatrix and found acanthostyles. Accordingly, this species is considered here to be a junior subjective synonym of P. falesi. Bork and Perry (1967) describe Prasopora simula- trix from the Champlainian of Illinois, Iowa, and Wis- consin. Their specimens were noted to contain no acanthostyles. Consequently, they are not considered to represent P. falesi. Sparling (1964), in describing an occurrence of Prasopora simulatrix from Michigan, noted a similar lack of acanthostyles. Distribution.—Localities NL IV, CB. Studied material.—Hypotypes NL IV 45(80)A (M) [USNM 431717], NL IV 45(80)B (M) [USNM 431718], NL IV 47(82)D (M) [USNM 431719], NL IV 49(84)A-3L-Z (M) [USNM 431720], NL IV 49(84)A-7R-D (M) [USNM 431721], NL IV 49(84)A- 7R-I [USNM 431722], NL IV 49(84)A-5R-B [USNM 431723], NL IV 51(86)A-11L-B [USNM 431724], NL IV 61(96)A-8-G [USNM 431725], NL IV 63(98)B- 4LB-FF [USNM 431726], NL IV 72(107)B-3-I [USNM 431727], NL IV 108(153)A-7-I [USNM 431728], CB 54A-7-B (M) [USNM 431729], CB 55B- 2-C (M) [USNM 431730], CB 138B-9-C (M) [USNM 431731], CB 145B-5-A (M) [USNM 431732], CB 145C-4-B (M) [USNM 431733], CB 55B-2-B [USNM MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH 35 Table 9.—Quantitative data, Prasopora falesi (James). See Key to Abbreviations, p. 33, for explanation. Character Range Mean Mode S.D. No. meas. No. spec. ZCD INDE EVAl cee cents .24—.32 28 28 O17 50 5 CBi54—95) 1-3-0 25-.32 Di 26; 27, O17 20 A CB 138-145 ...... .22-.29 26 26 019 30 3 GB Totals .-c .22—.31 26 26 .020 50 5 TOWAL® jocceccsese .22-.32 Py 28 .020 100 10 ZCD (mac) INDI, Sep Adinonduae -34—.50 40 40 032 50 5 @BI54—55) so.-- =. 38—.46 42 44 .029 15 2 CB 138-145 ...... 36—.50 42 38 044 25 3 GB lotallenes.cceae 36-.50 42 44 .039 40 5 MODAL a 3.2.rescmee 34-.50 41 38, .40 .036 90 10 ZWT INES IV, feencetecccet's =.01 = — -- 5 G@B'54=55 .....<-2- =.01 as — — — 2 @BM38=145) 2225-- =.01 a= = a 2 02—.04 .03 03 007 10 1 CBitlotal ee... se =.01 — — — — 4 02—.04 03 03 007 10 1 MOTTA se: =.01 os — — _ 9 02—.04 .03 03 -007 10 i Z/mm? INTE iis acictern slats 12-18 16 16, 17 19 11 5 (Cls}ioy. Ss) socacaeon 14-17 16 — 2.1 2 2 CB 138-145 ...... 17-21 18 17 ile7/ 3 CB ilotal ern... 14-21 17 il7/ 2.1 7 5 OIA vieaceistsisisictete 12-21 16 117/ De 18 10 MxMCD NIDULWV dacsang- ese .03—.17 08 09 03 25 5 G@ByS4=S5' « «5-02 .04—.10 07 07 02 10 2 CB 138-145 ...... .03—.09 07 09 02 15 3 GB) Total! ~~ <5-.--5- .03—.10 07 08 02 25 5 MOWAT Rocce .03—.17 08 09 03 50 10 MnMCD IN} OR AYA easaaanbepcas -02—.12 06 07 02 25 5 CBY54=95) ccc. sists .02—.10 05 04, .06 02 10 2 CB 138-145 ...... -02—.08 05 05 02 1S 3 GB Mlotaliene eee. -02—.10 05 04, 05 02 25 5 AKOAUANE, oaccoppacee 02-.12 05 04 02 50 10 MxMCD (mac) INDI aoe na cesnceee .O5—.23 09 08, .09 04 25 5 EB'S4=55) .ho.220- .O5—.14 09 .O7 03 10 2 @BiIS8—145) ..-2.- .04—.17 08 08, .09 03 15 3 CB Total! 22.22.72: .04—.17 09 07 .03 25 5 MOWAL s2..:ccee .04—.23 09 08 .03 50 10 MnMCD (mac) INDI Gi erersisiastesorototare .03—.09 06 07 .02 25 5 CBS54 55 eccewcrece .04—.12 06 05 .02 10 2 CB 138-145 ...... .02—.08 10) OS .02 15 3 CBMiotall eee ac. caer .02—.12 06 OS .02 75) se) MOTAL, oye. ts 2 .03—.12 06 05 02 50 10 431734], CB 67B-8-C [USNM 431735], CB 67B-7-A [U CB 54A-5-A (F) [USNM 431738], CB 55A-3-A (F) {U CB 114A-1-A (F) [USNM 431741], CB 150B-4-C (F) [U SNM 431736], CB 54A-6-A (F) [USNM 431737], SNM 431739], CB 55B-1-A (F) [USNM 431740], SNM 431742], CB 150B-6-B (F) [USNM 431743]. Genus MESOTRYPA Ulrich, 1886 Type species.—Diplotrypa infida Ulrich, 1886, p. 88. Mesotrypa angularis Ulrich and Bassler, 1904 Plate 1, Figures 3—4 Mesotrypa angularis Ulrich and Bassler, 1904, p. 23, pl. 7, figs. 7— 9; Karklins, 1984, p. 134-136, pl. 9, pl. 10, fig. 4. Description.—Zoarium hemispherical, discoidal, conical, encrusting. Zooecial cavity outlines in early part of colony subrounded, near-surface cavities po- lygonal with larger diameter (as mesozooecia are ab- sent). Walls thin, thicken slightly and composed of fine 36 BULLETIN 353 Table 10.—Quantitative data, Mesotrypa angularis Ulrich and Bassler. See Key to Abbreviations, p. 33, for explanation. Character Range Mean Mode S:D: No. Meas. No. Spec. ZCD (mat) NL IV 24-61 (59-96) ......... .23—.36 .28 27 .029 35 7 NL IV 85-116 (120-151) ..... .24-—.31 27 26 O15 29 6 INDI Totall Bre -eecccace ries .23-.36 .28 sD 024 64 13 (@)3). S425). paconomnasbonencocnodae .24—.29 27 .26 O14 10 2 CBM ARTASS a anccatercteteceee se .23—.32 a2 28 .024 10 2 CB Total .23—.32 2, .26, .28 .020 20 4 FIC Mig saaacetie sc ccsceceeses* case .24—.28 26 -~ 016 5 1 \ Aes dencoepsenodcescenagancenacnad —_ = — _ — — WES)D Totall siacnccscescoeerscnee .24—.28 26 — 016 5 1 ANON Dato chonanenascsaeocnpGaneaee .23-.36 27 26 020 89 18 ZCD (mac/mat) NL IV 24-61 (59-96) ......... .28—.50 sole) 36 053 35 7 NL IV 85-116 (120-151) ..... 38-48 41 40 .026 15 3 INTL INA AKO eT ls Conaconooaadopacaaaod .28—.50 “39 40 047 50 10 (@)3} is) St Sppeancncoeectacasanads 36-46 41 40 029 10 2 (@)s} WIN nS) ooocunaansoosasooed .36-.44 40 38 .033 10 2 CB Total 36—.46 40 40 030 20 4 HEM iisctienccemeosccisioasen cesses .38—.46 41 38 034 5 1 WB arrstcts oie siete icin er bieteistticletns ness a — ~ — — — \WWABISIE IKeHL GéGannacsassocacanood .38—.46 41 38 034 5 1 ROTATE Grenstaceiaretsrciae elcinteievetefete os .28—.50 40 40 042 75 15S ZCD (non-mat) NL IV 24-61 (59-96) ......... .22—.30 26 .26, .27 .022 35 7 NL IV 85-116 (120-151) ..... .18—.29 24 25 .020 40 8 INIESIV) Motal-eriscieciseeeiecscece. .18—.30 25 25 .022 75 15 G@Be55—85 wa citeceeie ee teese sete .23-.28 25 24 O17 15 3 CBMUWARK14 5) ees senimaeeaeeeriec 23-.32 26 PDD PAT 022 20 4 CB Total 23-.32 26 27 020 35 7 13 (OI Ire ondhmociacnnpneapehnscrouas -= — = — — —_ WIB! i sosicransnceatsaemerierssoeens .23—.32 26 — 035 5 1 WIE Siailotal teraseper cartes setts .23—.32 26 035 5 1 TROPA E, Aassnposoaandbouccdadenace .18—.32 25 25 022 115 23 ZCD (mac/non-mat) NL IV 24-61 (59-96) ......... 36—.54 42 40 042 25 5 NL IV 85-116 (120-151) ..... .36—.46 539) 40 026 35 V INIA OY, iWolealll . Seapnoboaoteeqeonaen 36—.54 40 40 .036 60 172 GBiSS=85) nescence accesses .34—.42 37 36 023 10 2 ee ee Syy Sonneedodaccopsaccn -38—.48 43 44 031 15 3 CB Total 34-48 41 38, .44 040 25 5) HI GMip eats, Jens hectare see _ — — — _ —_ WIBIM. o-wcmademocisdelesisimeerinass cre 40—.46 42 40 028 5 1 WIE SMe lotalns ccrctiess seer aat 40—.46 42 40 028 5) 1 IKO)IVN I Basnonacaadsedoasbocaarode 34-54 41 40 036 90 18 ZWT NE IV 24-61 (59-96) ......... .01—.04 02 .02 .007 35 7 NL IV 85-116 (120-151) ..... .O1—.03 02 .02 -006 30 6 NERV) otal ae eects ster teleiseis .O1—.04 02 .02 .007 65 13 EByS5—85 oe aeesecenicnecessemeseits -01—.02 .02 .02 00S 10 2 CBMIVAS TAS retacnctsceeneliatioe .01—.04 02 02 O10 9 2 CB Total .O1—.04 .02 .02 008 19 4 1G CG). We aepeapaaetonseobaacocHosdaa’ 01—.02 Ol Ol 002 5 1 IWIB eee deanna cnt ceece eet ctites --- a i -- = = WEST Qotall teascceceseaccee sere .01—.02 Ol Ol 004 5) 1 TOTAL piacctccctoiseic sitesi .01—.04 02 02 .007 89 18 Z/mm? (mat) NL IV 24-61 (59-96) ......... 16-19 17 16 1.0 17 6 NL IV 85-116 (120-151) ..... 17-20 19 19 Ia 5 4 NERV sMotaliy sear anseseae secre 16-20 17 16 1.2 22 10 GBYSS=85 grace sas ccsesce eee 19-21 20 — 1.4 2 2 CBuITF ESTAS! se sdsissteletecisstqaucices 15-17 16 — 1.4 2 1 CB Total 15-21 18 _ 2.6 4 3 18). loca aReBpannAcAaapRanArooacrer 19-20 20 — 0.7 2 1 i Seceaarabbnasnsarchpasenane sade — — — — == = WES Totale saaas-tastcceecin eect 19-20 20 —_— 2 1 tN co — £ ANOKIVANED Ge oaunndosadanuecneaooDade 15-21 18 16 1) MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH 3i7/ Table 10.—Continued. Character Range Mean Mode S.D. No. Meas. No. Spec. Z/mm? (non-mat) NE IV 24-61 (59-96) ......... 16-21 19 18 1.3 14 W NL IV 85-116 (120-151) ..... 17-22 20 22 ile7/ 9 8 INSeeUV total yaceacce-emreecreeis 16-22 19 18, 19 1.7 23 15 GSBIDSS85) tare gacneeat taeeehisemme 17-22 20 20 2.1 4 3} SBT ASMA SSS sristrecisicictengahicracars 16-21 18 18 1.7 W 5) CB Total 16-22 18 20 ES) 11 W LG Meer ctrsrsete eteretetareiseioraisteisent eter — — — — — — IW rterctcrctarc erator a slatsiajefgte sin anielasctaret 18-21 20 oe Dal 2 1 WIEST Total Yoreccseccsasectenest 18-21 20 _ 2.1 2 1 IROL: Sebndaoceatsacnasseccapade 16-22 19 18 1.8 36 23 MxMCD (non-mat) NE IV 24—-61 (69-96) ......... .04—.26 10 08 .038 40 8 NL IV 85-116 (120-151) ..... -06—.16 10 .09 .025 40 8 INE MIWeMotaliesseseseeatce dice. .04—.26 10 09 .032 80 16 CBrSS R89 eee ticlesiecerlae se cisscs .06—.14 09 10 .023 1S 3 GBA A VAS IS caccictceetetceinsteineate .05—.15 09 10 024 20 4 CB Total .O5—.15 09 10 023 35 a 15 (CIM (sat openachcade eee a mABaGeE aenr — a — — a= — IWIBRe ptsmes cea ae ters alee tech sare -10—.15 13 — 019 5 1 Wis SieiLotallemencn:Aa-t-etasaert -10—.15 13 — O19 5 1 INOIVANS asassecnqcenccmcanerdsenca .04—.26 10 08 032 120 24 MnMCbD (non-mat) NL IV 24-61 (59-96) ......... .03—.10 .06 07 NL IV 85-116 (120-151) ..... .03—.11 06 06 018 40 8 INDEVIV otal ye facteresiceiete setesislsisicle .03—.11 06 05 -O17 40 8 (CEBESS— 85 ecco st osaec saci .04—.09 06 06 O18 80 16 GBA VAST wramastciclerele secleieteia's .04—.10 07 06, .07 O17 15 3 08 OLS 20 4 CB Total .04—.10 07 06 016 35 7 IEG Soosaceodos poo aoDoNaLEbogece — — —_ — = — WWIB ES ciisialers sfssfeinis sl sl-tajeieisclele sisieleisaie .O5—.08 07 07, .08 O12 5) 1 WIEST Total ermsscceass-recocee ss .O5—.08 07 07, .08 O12 5 1 MOWATS te stistcctcecstecscse celeste .03—.11 06 06 O17 120 24 AD (lam/mat) NL IV 24-61 (59-96) ......... .04—.09 06 06 .012 35 7 NL IV 85-116 (120-151) ..... .04—.08 05 O5 010 30 6 INTE, IY Theft) Ae chmeasoceddononden .04—.09 06 06 O11 65 13 (C13) SE 8S) | peesonasdnsooonedacgoad .03—.08 06 03, .08 .022 10 2 (Elz) Wide Syea eS ensecancacnsoaded .03—.04 04 04 00S 10 2 CB Total .03—.08 05 04 O18 20 4 lalCIMl esaacséadee aneessooooanocdsn .03—.06 05 05 O11 5 1 V3 nce ceoctnsctnaodeasnagnocabases — = = = = = WES Teotalifrccretecticcctieseces .03—.06 05 OS O11 5 1 TROMUND, ponorsnaaceneHeeooeadcenbe .03—.09 05 OS O14 90 18 V-shaped laminae near periphery or cyclically within zoarium (planes of rejuvenation). Diaphragms thin, variable in number, spacing, orientation, absent or sparse proximally becoming more common peripher- ally and near colony-wide surface of rejuvenation where they are approximately spaced at one-half to one zooecial cavity diameter apart, mainly planar to curved convex outwards and inclined towards colony center, some cystose, wavy, overlapping, few cysti- phragms. Mesozooecia fairly common in non-periph- eral parts of colony, cavities polygonal in cross-sec- tional outline being mainly three- and four-sided, de- crease in diameter outwards and disappear before reaching colony surface, few become autozooecia. Di- aphragms present throughout, mostly evenly spaced at approximately one-half to one mesozooecial cavity di- ameter apart, thickness similar to autozooecial dia- phragms, walls commonly moniliform. Acanthostyles common, mainly in later parts of colony or early parts where walls thicken, mainly at zooecial corners though occasionally found between zooecia, concentric lami- nae surrounding some styles inflect zooecial cavities. Commonly three to five surround each zooecium. Maculae of megazooecia found throughout colony and flush with colony surface. Zooecia of maculae in ear- lier portions of colony comparable in diameter to non- macular zooecia of periphery (though latter polygonal and former subrounded). 38 BULLETIN 353 Measurements.—Measurements are summarized in Table 10. Remarks.—Mesotrypa angularis typically has an- gular autozooecial cavity outlines in the peripheral re- gion, inclined and planar to distally curved exozonal diaphragms spaced between one-half to one zooecial cavity diameters apart, numerous exozonal acantho- styles found mainly at zooecial corners, thin walls, ab- sent to rare cystiphragms, common mesozooecia in the endozone which have polygonal cavity outlines and become crowded out peripherally, and distinctive mac- ulae composed of large autozooecia. The present species is similar to M. infida but for lesser numbers of diaphragms colony-wide and in par- ticular early parts of the colony, and for fewer and less pronounced curved oblique cystiphragm-like dia- phragms. Fritz (1957) recognized a subspecies of M. angu- laris called parvatrypa. Distribution.—Localities NL IV, CB, HCM, WB. Studied material.—Hypotypes NL IV 24(59)-B-3-B (M) [USNM 431744], NL IV 49(84)A-3L-X (M) [USNM 431745], NL IV 49(84)A-4L-H (M) [USNM 431746], NL IV 49(84)A-3L-W (M) [USNM 431747], NL IV 49(84)A-2L-A (M) [USNM 431748], NL IV 49(84)A-5R-HH (M) [USNM 431749], NL IV 49(84)A-7R-R (M) [USNM 431750], NL IV 61(96)A- 1-C (M) [USNM 431751], NL IV 61(96)A-9-G (M) [USNM 431752], NL IV 61(96)A-8-C (M) [USNM 431753], NL IV 61(96)A-6-K (M) [USNM 431754], NL IV 85(120)A-10L-A (M) [USNM 431755], NL IV 85(120)A-8L-A (M) [USNM 431756], NL IV 93(128)A-13-A (M) [USNM 431757], NL IV 94(129)A-3L-D (M) [USNM 431758], NL IV 96(131)B-4-A (M) [USNM 431759], NL IV 100(135)A-2L-O (M) [USNM 431760], NL IV 100(135)A-10L-A (M) [USNM 431761], NL IV 108(143)A-4-A (M) [USNM 431762], NL IV 108(143)A-17-C (M) [USNM 431763], NL IV 116(151)A-1-E (M) [USNM 431764], NL IV 30(65)C- 3L-A [USNM 431765], NL IV 37(72)B-5-L [USNM 431766], NL IV 44(79)E-7-B [USNM 431767], NL IV 61(96)A-7-F [USNM 741768], NL IV 61(96)A-9-C [USNM 431769], NL IV 61(96)A-5-A [USNM 431770], NL IV 63(98)A-5LA-H [USNM 431771], NL IV 63(98)A-6LA-H [USNM 431772], NL IV 72(107)B-4L-B [USNM 431773], NL IV 85(120)A- 12L-A [USNM 431774], NL IV 108(143)A-12-E [USNM 431775], NL IV_ 116(151)A-3-G [USNM 741776], NL IV 117(152)A-2-C [USNM 431777], CB 55A-2-A (M) [USNM 431778], CB 57A-3-A (M) [USNM 431779], CB 62A-5-A (M) [USNM 431780], CB 67B-8-A (M) [USNM 431781], CB 85A-11L-A (M) [USNM 431782], CB 114A-1-B (M) [USNM 431783], CB 128B-4-B (M) [USNM 431784], CB 138A-5-A (M) [USNM 431785], CB 145C-4-A (M) [USNM 431786], CB 145B-2-A (M) [USNM 431787], CB 54A-7-A [USNM 431788], CB 145B-4-B [USNM 431789], CB 50B-4-A (F) [USNM 431790], CB 55A- 9-B (F) [USNM 431791], CB 55A-9-A (F) [USNM 431792], CB 72C-2L,a-A (F) [USNM 431793], CB T4A-5L-A (F) [USNM 431794], CB 79A-4-A (FP) [(USNM 431795], CB 85A-17L-A (F) [USNM 431796], CB 132A-A (F) [USNM 431797], CB 161A- 3-C (F) [USNM 431798], HCM 43(82)C-3-II (M) [USNM 431799], WB 38(50)B-3-A (M) [USNM 431800]. Mesotrypa sp. A Plate 2, Figure 1 Description.—Zoaria encrusting. Zooecia rounded to subrounded in non-peripheral region, subrounded to subpolygonal in periphery. Except for encrusting base, zooecia perpendicular to colony surface. Walls mod- erately thin, even thickness, composed of U- to V- shaped laminae. Diaphragms variable in orientation, perpendicular to inclined to zooecial walls, curved or planar, thin, some overlapping, spacing variable, two to several within one zooecial cavity diameter. Cysti- phragms and/or cystose diaphragms on distal side of zooecial tube. Outwards, attached to zooecial wall, in- ner end attached to diaphragm or other cystiphragm or cystose diaphragm. Mesozooecia common, angular, fill voids left by contact of rounded to subrounded zooecia in non-peripheral parts of colony, crowded out zooe- cially outwards, diaphragms mainly perpendicular to walls, some inclined slightly, spaced at one-half to one mesozooecial cavity diameter apart, some thicker than for autozooecia. Acanthostyles prominent throughout colony, laminar sheaths thick and distinct, thicker in periphery where mesozooecia absent, two to three at zooecial corners surround zooecial cavities in non-pe- ripheral region, in periphery three to four surround zooecia mainly at zooecial corners. Measurements.—Measurements are summarized in Table 11. Remarks.—Specimens assigned to Mesotrypa sp. A have numerous large acanthostyles with thick laminar sheaths found mainly at zooecial corners, subrounded to subpolygonal peripheral zooecial cavity outlines, moderately thin walls, variably oriented diaphragms, some cystiphragms, common angular mesozooecial cavities, and an encrusting habit. Mesotrypa sp. A differs from M. spinosa by having both larger acanthostyles and zooecial cavity diame- ters, and possibly by the more variable orientation of diaphragms. Ulrich’s description (1893, p. 259) noted “mostly oblique curved partitions in zooecial tubes” MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH 39 Table 11.—Quantitative data, Mesotrypa sp. A. See Key to Abbreviations, p. 33, for explanation. Character Range Mean Mode S.D. No. Meas. No. Spec. ZCD (EIB sconooondooa .23—.28 .26 28 O18 10 2 TOTATE recess .23—.28 26 .28 O18 10 2 ZWT EB Beaseecss store .01—.02 02 02 003 10 2 OWA eee... .01—.02 .02 02 003 10 2 MCD (endo/ht) (Gl) Sascachemdanr .07—.09 08 07 008 10 2 MOWAT Reeeeee .07—.09 08 07 008 10 2 MCD (endo/wth) (Cle}. jcebcnapnnaot -05—.08 06 OS O10 10 2 MOTTA sa.cn. -05—.08 .06 O5 O10 10 2 AD (lam/exo) CBs tes.neoscre .06—.12 09 06 .024 10 2 ROTA 2 sg .06—.12 09 .06 024 10 2 AD (lam/endo) (C13 onescoorsonce .04—.06 05 .04 008 10 2 OWMAU eraser .04—.06 05 04 008 10 2 for M. spinosa, however, his figured specimen, pl. 17, fig. 12, is not dissimilar from the present species. The small sample size of Mesotrypa sp. A further precludes a more precise taxonomic assignment. Distribution.—Locality CB. Studied Material.—Hypotypes CB 114A-9-A (M) [USNM 431801], CB 116A-5-A (M) [USNM 431802]. Genus PERONOPORA Nicholson, 1881 Type species.—Chaetetes decipiens Rominger, 1866. Peronopora mundula (Ulrich, 1893) Plate 2, Figures 2-3 Homotrypella mundula Ulrich, 1893, p. 232, 233, fig. 12; Brown, 1965, p. 980, 981, pl. 111, figs. 4-6. Description—Zoaria mainly ramose, some encrust- ing. Zooecia initiated throughout inner and outer en- dozone. Zooecial cavities polygonal in cross-section in endozone, subrounded within inner exozone, becom- ing increasingly polygonal zooecially outwards. Zooe- cia curve very shallowly in endozone, curve greatly accelerated near endozonal/exozonal transition with or without a distinct zooecial bend at exozonal base or lower exozone, or intersect colony surface at right an- gles. Zooecial walls thicken markedly at base of exo- zone or in lower exozone and formed of distinct V-shaped laminae. Walls commonly thicken and thin zooecially outwards. Occasionally a dark line separates zooecial walls. Endozonal walls even to slightly irreg- ular, parallel. No median layer in zoarium. Diaphragms in endozone planar, thin, perpendicular to zooecial walls, spaced at two to several zooecial cavity diam- eters apart in inner endozone, one-half to two zooecial cavity diameters in outer endozone. In innermost exo- zone, diaphragms few, occasionally absent, spaced at approximately one-half to two-thirds of a zooecial cav- ity diameter, mainly perpendicular to zooecial walls, some inclined, curved slightly, locally overlapping. Absent outwards. Overlapping cystiphragms common in outermost endozone and exozone on distal sides of zooecial tubes. In exozone, cystiphragms usually smaller, more closely and regularly spaced. In some zooecia cystiphragms absent in outer exozone. Some cystiphragms with one or two connected diaphragms in outer endozone and inner exozone. Occasionally cystiphragms absent or one or two isolated. Cysti- phragms extend one-third to one-half of the way across zooecial cavity in longitudinal section, greater for in- nermost cystiphragms. Mesozooecia scattered about exozone, some fairly large and locally abundant, less angular and commonly larger outwardly, with or with- out loss of diaphragms so as to be indistinguishable from autozooecia in tangential section, diaphragms thicker than for autozooecia. Acanthostyles numerous, found in outermost endozone and in exozone at zooe- cial corners or between zooecia, diameters of lumen constant, laminar sheaths thickest in outer exozone. Acanthostyles commonly inflect zooecial cavities, usu- ally offset in exozone, three to six around each zooe- cium, commonly four to five. Measurements.—Measurements are summarized in Table 12. Remarks.—Peronopora mundula characteristically has subrounded to subpolygonal zooecial apertures in the exozone, distinct V-shaped zooecial wall laminae, endozonal diaphragms spaced at two to several zooe- cial cavity diameters apart within the inner endozone, and one and one-half to two zooecial cavity diameters apart in the outer endozone, few to sometimes no di- aphragms within the inner exozone and none in the outer exozone, overlapping cystiphragms present from outer endozone to colony surface but sometimes ab- 40 BULLETIN 353 Table 12.—Quantitative data, Peronopora mundula (Ulrich). See Key to Abbreviations, p. 33, for explanation. Character Range Mean ZCD INTE Ye omceonae .14—.22 sid) AKOMUANE, soccosan .14—.22 a7) ZWT INT a scn eens .04—.10 06 MOTAL Meese: .04—.10 06 Z/mm-? INT ERIN nenogouee 22-29 25 TKOM MANU, Qoceeoos 22-29 25 AD (lam) INTE DWs eseeee ese .04—.07 06 TOTAL esse .04—.07 06 sent in outer exozone, mesozooecia scattered about exozone, numerous acanthostyles surrounding each zooecium (commonly four to five), and numerous styles inflecting autozooecial cavities. P. mundula differs from P. weirae in having distinct V-shaped wall laminae, greater numbers of endozonal and exozonal diaphragms, fewer mesozooecia, and in- creased numbers of inflecting acanthostyles. In comparing Homotrypella with Peronopora, Ul- rich (1893, p. 228) noted the following differences be- tween the genera. In Peronopora the zoaria are bifo- liate and, additionally, “the cystiphragms are devel- oped in an almost uninturrupted [sic] series throughout the length of the zooecial tubes.”” Cystiphragms in Homotrypella, on the other hand, are “‘developed chief- ly in the median region of the zooecial tubes, being absent usually just beneath the surface and never pres- ent in the axial region.” Boardman and Utgaard (1966, p. 1097) revised Per- onopora to include forms “differing significantly from the type species only in growth habit” as this “‘is con- sistent with present concepts of many other genera of Trepostomata ...”’ In addition, they note that cysti- phragms are “rare in the endozone of zoaria lacking a median or basal layer.”” In forms with a median layer, cystiphragms commonly extend from the median layer through most of the exozone. It is assumed that in non- bifoliate growth habits, a cystiphragm distribution con- formable with Ulrich’s characterization of Homotry- pella would be applicable. Summarily, then, based on Boardman and Utgaard’s emendation of Peronopora, Ulrich’s differentiation of the genera is not valid. Further comparison of the above descriptions notes additional similarities between the two genera, namely, generally rounded zooecial cavity outlines; commonly “integrate”’ wall structure; the sometimes inflection of zooecial cavity outlines by acanthostyles; abundant acanthostyles; maculae that are low or flush with zoar- ial surface and have a central grouping of mesozooecia (Ulrich described maculae as mesopore clusters). Ul- rich and Bassler (1904, p. 21) described Homotrypella Mode S.D. No. Meas. No. Spec. 16 021 25 5 .16 021 25 5) .08 O19 25 5 .08 O19 25 5 — 3.8 3 3 — 3.8 3 3 05, .06 O10 25 5 05, .06 O10 25 5 nodosa and indicated that “‘sections cutting across zooecia just beneath the surface of an old branch often exhibit no mesopores, the zooecia being polygonal. At deeper levels mesopores can always be detected and generally become so numerous as to isolate the zooe- cia.”” While this phenomenon is not noted in Ulrich’s original description of Homotrypella, Ulrich and Bass- ler stated that the new species, H. nodosa does not modify the generic definition of Homotrypella. Board- man and Utgaard (1966) described the same crowding out of mesozooecia in their revision of Peronopora. This would suggest further that Ulrich’s concept of Homotrypella is incorporated into Boardman and Ut- gaard’s Peronopora. The present author is not able to distinguish the two genera and suggests that Homotrypella Ulrich, 1886, indeed be a synonym of Peronopora Nicholson, 1881. Distribution.—Localities NL IV, CB, WB. Studied material.—Hypotypes NL IV 50(85)A-14-B (M) [USNM 431803], NL IV 50(85)A-16-B (M) [USNM 431804], NL IV 61(96)A-4-A (M) [USNM 431805], NL IV 61(96)A-7-I (M) [USNM 431806], NL IV 63(98)B-3LA-M (M) [USNM 431807], NL IV 51(86)A-9L-A [USNM 431808], NL IV 51(86)A- 2L-C [USNM 431809], NL IV 61(96)A-6-N [USNM 431810], NL IV 61(96)A-5-W [USNM 431811], NL IV 63(98)B-6LA-B [USNM 431812], NL IV 63(98)B- 2LA-R [USNM 431813], NL IV 66(101)A-7-A [USNM 431814], NL IV 66(101)A-5B-A [USNM 431815], NL IV 66(101)A-9-A [USNM 431816], NL IV 72(107)A-3L-E [USNM 431817], NL IV 61(96)A- 8-E (F) [USNM 431818], NL IV 63(98)B-3LB-T (F) [USNM 431819], CB 67B-1-A,B [USNM 431820], CB 153B-3-A [USNM 431821], WB 19(31)A-5L-A [USNM 431822], WB 20(32)B-5-B [USNM 431823]. Peronopora weirae, new species Plate 3, Figures 1—2 Description.—Zoaria mainly ramose, some encrust- ing. Zooecia initiated homogeneously throughout inner and outer endozone. Zooecial cavities polygonal in MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH 41 Table 13.—Quantitative data, Peronopora weirae n. sp. See Key to Abbreviations, p. 33, for explanation. Character Range Mean MxZCD INTIGIIN Ze canaceer .14—.20 18 CBee vincaseniss .12-.18 16 IG Miaeeree ese .16—.22 18 INOVIVAIE, —eanane .12-.22 oil 7/ MnZCD IND ERIN Ssantsndec .07—.14 oll CBE Se iias entices .07—.10 08 IGM. reccsecce .07—.12 .09 MOTAL, sci :s:<5' .0O7—.14 10 ZWT INTE ace aces .O5—.12 07 CBs sreccei sen. .02—.06 04 13 (Gl Ineaeanentes .04—.08 .06 MOWAIGS eee .02—.12 .06 Z/mm? NESLV. of cnciase is 21 21 CBr sac ssencesons 30 30 HEM. wi. c sess: 26-27 26 TOTAL, se. 21-30 26 AD (lam) INE IVE re esc are .04—.05 .04 CBieensseeecases .04—.08 .06 FI@ Miers eee .04—.08 .06 TMOWUNE, coseocs .04—.08 05 cross-section in endozone, subrounded to subpolygon- al in exozone. Sometimes elongate zooecia oblique to colony surface. Zooecia curve shallowly in endozone, curve accelerated near endozonal/exozonal break with or without a zooecial bend at exozonal base or lower exozone. Zooecia intersect colony surface mainly at or near 90°. Zooecial walls commonly thicken abruptly at base of exozone or in lower exozone, granular to formed of poorly defined U- to V-shaped laminae. Oc- casional dark line marks zooecial boundary in longi- tudinal section. Endozonal walls even to slightly irreg- ular, parallel. No median layer in zoarium. Diaphragms rare in endozone, few zooecia with one or two. Dia- phragms absent to uncommon in lower exozone, one or two, rarely more, thin, planar, sometimes curved, perpendicular to zooecial walls, some inclined. In en- crusting forms, diaphragms more common with or without mesozooecia changing to autozooecia and vice-versa. Cystiphragms in most zooecia, overlapping in outermost endozone and exozone, sometimes absent in outer exozone. Occasionally only one or two iso- lated in zooecial tube. Cystiphragms extend one-third to one-half of the way across zooecial cavity in lon- gitudinal section, greater for innermost cystiphragms. Mesozooecia abundant, commonly separate zooecia in inner exozone, become crowded out outwards by au- tozooecia, few mesozooecia become autozooecia, di- aphragms spaced one-half to one mesozooecial cavity diameter apart, diaphragms distinctly thicker than for autozooecia. Acanthostyles numerous, many slightly Mode SD: No. Meas. No. Spec. 18 O19 10 2 16 .022 5 1 16 .025 10 2) 16 023 25 5 oll) .020 10 2 08 O11 5 1 09, .10 014 10 2 10 -020 25 > 06 .022 10 2 03 .O1S 5 1 .06 O14 10 2 .06 .022 25 5 21 OO 1 1 .0O 1 1 71 2 D = 3h 7/ 4 4 04 00S 10 2 07 .016 5 1 06 013 10 2 04 O13 25 5 inflect zooecial walls, many offset, laminae not thick, found in outermost endozone and exozone at zooecial corners and between zooecia, three to six around each zooecium, commonly four to five. Etymology.—This species is named for Frances Weir, my spouse, whose encouragement and support have helped keep me in the Ordovician. Measurements.—Measurements are summarized in Table 13. Remarks.—Peronopora weirae differs from Peron- opora mundula in having walls that vary from granular to having poorly defined U- to V-shaped laminae, few- er endozonal and exozonal diaphragms (rare in endo- zone, absent or nearly so in inner exozone, absent in outer exozone), abundant mesozooecia, and less acan- thostyles that inflect zooecial cavities. Distribution.—Localities NL IV, CB, HCM, WB. Studied material.—Holotype NL IV 72(107)A-3L-H (M) [USNM 431824], Paratypes NL IV 72(107)B-2L-G (M) [USNM 431825], NL IV 61(96)A-2-A [USNM 431826], NL IV 61(96)A-3-B [USNM 431827], NL IV 72(107)B-2L-A [USNM 431828], NL IV 72(107)B- 2L-I [USNM 431829], NL IV 93(128)A-10-E [USNM 431830], NL IV 93(128)A-10-F [USNM 431831], NL IV 93(128)A-1-O [USNM 431832], NL IV 108(143)A- 2-H [USNM 431833], NL IV 61(96)A-5-I (F) [USNM 431834], CB 74—75A-2-A (M) [USNM 431836], CB 72B-6-A [USNM 431837], CB 150B-1-B [USNM 431838], CB 161A-1-A [USNM 431839], CB 62A- 10-C (F) [USNM 431840], CB 72C-5L-A (F) [USNM 42 BULLETIN 353 431841], HCM 43(82)B-7-A (M) [USNM 431842], HCM 43(82)A-3-T (M) [USNM 431843], HCM 43(82)A-1-C [USNM 431844], HCM 43(82)C-6-N [USNM 431845], WB 20(32)B-3-B [USNM 431846], WB 27(39)B-4-A [USNM 431847], WB 44(56)C-2-A (F) [USNM 431848], WB 44(56)B-2-B (F) [USNM 431849]. Genus ACANTHOLAMINATUS, new genus Type species.—Acantholaminatus typicus new ge- nus, new species. Description.—Characterized by the presence of a largely granular wall structure, abundant cystiphragms and diaphragms, plentiful distinctive, well-developed, and commonly inflecting acanthostyles throughout the colony, rare mesozooecia, and subrounded zooecial cavity outlines. Etymology.—Referring to the prominent acantho- styles having distinct laminar sheaths. Remarks.—In having abundant cystiphragms and diaphragms this genus is similar to Monticulipora as well as Atactoporella. It is further similar to Monti- culipora in having poorly defined (granular) wall structure. It differs from Monticulipora in the devel- opment of acanthostyles, lack of mesozooecia in mac- ulae, more rounded zooecial cavity outlines, and ab- sence of mural lacunae. It differs from Atactoporella in having fewer offset and inflecting acanthostyles and in lacking numerous mesozooecia. Acantholaminatus typicus, new genus, new species Plate 3, Figure 3 Plate 4, Figure 1 Description.—Zoaria encrusting. Zooecia initiated from surface of object encrusted by zoarium and rap- idly attain an orientation perpendicular to the colony surface. Zooecia with fairly small and subrounded cav- ity outlines. Zooecial walls of even thickness through- out except at basalmost position where zooecial walls thinner. Walls usually granular, sometimes with faint U- to V-shaped laminae. Diaphragms found through- out colony, commonly attached to adjoining cysti- phragms, consistently thin, orientation variable, flat or curved slightly and perpendicular to inclined to zooe- cial walls, spacing variable, commonly two-thirds of a zooecial cavity diameter apart or less, locally greater or absent (the latter instance being especially so for outermost parts of the exozone), sometimes locally overlapping. Cystiphragms in nearly all zooecia, usually contin- uously overlapping and evenly distributed, on distal side of zooecial tubes, approximately one-third of the way across zooecial cavity in longitudinal section, more so at zooecial bend at very base of colony, wrap around one-third to one-half perimeter of zooecial tube. One or two diaphragms usually attached to each cystiphragm, sometimes none. Mesozooecia very rare, small, some change into au- tozooecia. Diaphragms spaced at one mesozooecial cavity diameter apart, thicker than autozooecial dia- phragms. Acanthostyles plentiful, present at nearly all zooe- cial corners and sometimes between zooecia. Com- monly five acanthostyles surround any one zooecium (up to eight), often inflect into zooecial cavity, some offset and inflecting. Laminar sheaths surrounding each acanthostyle appear darker than wall laminae in acetate peel replicas. Maculae present, not distinctive. Walls and zooecial cavities slightly larger than for non-macular areas. Oc- casionally walls thick between adjacent zooecia where space filled by additional acanthostyles having thicker laminar sheaths. Etymology.—Indicating that this is the type species of the genus. Measurements.—Measurements are summarized in Table 14. Remarks.—Acantholaminatus typicus differs from A. multistylus primarily in having fewer acanthostyles surrounding each zooecium. A. typicus differs further in having thicker walls in non-macular areas and great- er numbers of diaphragms in the outer exozone. Distribution.—Localities NL IV, CB, HCM, WB. Studied material.—Holotype HCM 43(82)B-5-J (M) [USNM 431850], Paratypes NL IV 93(128)A-9-I (M) [USNM 431851], NL IV 93(128)A-9-E (M) [USNM 431852], NL IV 94(129)A-4L-B [USNM 431853], NL IV 100(135)A-10L-I [USNM 431854], NL IV 116(151)B-3-C [USNM 431855], NL IV 117(152)A- 5-A [USNM 431856], CB 46C-4-A (M) [USNM 431857], CB 123A-4-A (M) [USNM 431858], CB 122A-24-B [USNM 431859], HCM 18(57)B-4-J (M) [USNM 431860], HCM 43(82)C-1-G (M) [USNM 431861], HCM 43(82)C-2-Q (M) [USNM 431862], HCM 43(82)B-8-J (M) [USNM 431863], HCM 43(82)A-3-J (M) [USNM 431864], HCM 18(57)B-3-A [USNM 431865], HCM 43(82)B-2-C [USNM 431866], HCM 18(57)B-4-I (F) [USNM 431867], WB 44(56)B-3-B (M) [USNM 431868], WB 20(32)B-2-C (F) [USNM 431869]. Acantholaminatus multistylus, new genus, new species Plate 4, Figure 2 Description.—This species is morphologically sim- ilar to Acantholaminatus typicus in all respects with the primary exception of acanthostyle number. Differ- ences also exist in exozonal wall thickness and fre- MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH Table 14.—Quantitative data, Acantholaminatus typicus n. gen., n. sp. See Key to Abbreviations, p. 33, for explanation. Character Range ZCD INI eeetcnre cociarce .14—.20 GBige rs ccmetis seein 17-—.22 InlGl L Sasantoesosconn .14—.22 IWIBeaeuseeacncecisneis .17—.20 WEST Total ....... 14—.22 TOWAL cee ccniics .14—.22 ZCD (mac) INDECIIV Ss wacscinnienciats — GBP r er eens ee _ FI @Migeaessteiccscite .20-.27 WhASS. Headeoceoosseedas _ WES i dotaliecees.: .20—.27 OMA ses. eetesacees .20—.27 ZWT INTEL® S2ciis sisisteccisiaie .02—.05 CBeicrassecoseecene .02—.04 GME acsciarcta cia eran tatesare O01-.05 IWIBSS wc omcansocsacons .02—.06 IWESID Wotallceecce. 01—.06 ARON WAN EM conoaqcoose .O1—.06 ZWT (mac) INDEED os some cence — GB ercssecccece HEM ne eareats sebdasc 02—.06 IWiBigcrece peas cee oo WE Siilotaligeeesces 02-.06 PROWTAT ee access 02-.06 Z/mm? INTOMDV is ores stersioneciacetes 32-34 GB n ssoesasacnaechc. 30-31 HEM Sooecnseeees 30-39 WB ecys eee ee be 33 WIEST) Potalijse-es- 30-39 MOWAI v5. aceceeck 30-39 AD (lam) INDDVa eee oceee een .03—.06 CB iyetae. bee. eet Nee ae .03—.04 HG Mee noses aeeer. 03—.06 WIT 2 eects Ea .04—.06 WES Motallie.---- 03—.06 MOMAL 2 eo. 3eses3 .03—.06 AD (lum) NENG aa: Aas eeaee .01—.02 CBr a. cencoecacce ax 01 13 (GI come aoe CTE 01—.02 IWIB paces sirens octnsce .01—.02 WES dotall®-2.-- 01—.02 MOWAT e seems acecece .O1—.02 AD (lam/mac) IGM ei ccko ce eees: -04—.09 MOPAR feeb oecce 04—.09 AD (lum/mac) IGM? sasdeeeicecess 02 MOAT oe saceaas ae 02 quency of diaphragms in the outer exozone. A. multi- stylus has eight to twelve, commonly ten, acanthosty- les surrounding each zooecium; whereas A. typicus has less than eight, commonly five, acanthostyles around each zooecium. In addition, the present species is thin- ner walled in non-macular areas and exhibits a sparsity of diaphragms in the outer exozone. Mean Mode 17 18 19 .20 18 16 18 A8 18 18 18 18 24 5) 24 25 24 25 .03 02 03 02 .02 02 .04 04 03 02 .03 02 03 02 03 .02 .03 .02 33 30 = 33 31 33 33 33 3 33 3 S.D. -017 016 -020 No. Meas. 20 15 — SN Were NNN -— 43 No. Spec. BPXNeFe ANN _ | [eesell PARP ANN FF _ | ss] STO NwN ON Ae ff ff — i fs Cony Tod TS) NN pay Etymology.—Referring to the multitudinous acan- thostyles found in this species. Measurements.—Measurements are summarized in Table 15. Distribution.—Locality WB. Studied material.—Holotype WB 38(50)C-2R-A (M) [USNM 433073] 44 BULLETIN 353 Table 15.—Quantitative data, Acantholaminatus multistylus n. gen, n. sp. See Key to Abbreviations, p. 33, for explanation. Character Range ZCD WIB I eee saiseierrs 15—.20 AKONVN LG Seopaden 15-.20 ZCD (mac) IWIBS sieer stesciesyeie .23-.29 MOA eensceee 23-.29 ZWT WIBitSesesstexinae 01-.03 ANOMWAN Es Soogoone 01—.03 ZWT (mac) WIBY ses cecssses 03—.04 AROMA: coposuon 03-.04 Z/mm? WBE ecnmoseeecire 31-33 MOA eee 31-33 AD (lam)* Ms Saaotiaenoa cece 03 TOTAL varcccsec .03 AD (lum)* Waey Gonccaasedea 01 TOWATE: ci jcsess O1 * Measurements from larger, more visible acanthostyles. Genus HOMOTRYPA Ulrich, 1886 Type species.—Homotrypa curvata Ulrich, 1882, p. 242-243. Homotrypa minnesotensis Ulrich, 1886 Plate 6, Figures 1—2 Homotrypa minnesotensis Ulrich, 1886, p. 79; 1893, p. 235, 236, pl. 19, figs. 1-9. cf. Homotrypa cf. minnesotensis Ulrich. Fritz, 1957, pl. 14, figs. 1,2. Description.—Zoaria ramose. Most new zooecia initiated in outer endozone. Exozonal zooecial cavities subrounded to subpolygonal. Endozonal cavities po- lygonal to subpolygonal. Zooecia curve evenly in out- ermost endozone and lower exozone before straight- ening (in mature specimens) to intersect colony sur- face at approximately 70° to 80°. Zooecial bend oc- casionally in lower exozone. Surface angle sometimes higher, especially if zooecia curve slightly near pe- riphery. Endozonal walls thin, thickening gradually within zooecial bend attaining a moderate thickness that remains fairly uniform throughout exozone. Exo- zonal walls even to wavy to commonly crenulate. Sometimes beaded. Crenulation and beading occur be- fore that part of outermost endozone having dia- phragms. Endozonal zooecial diameters constricted in outermost endozone. Occasional megazooecium with- in inner endozone. Exozonal walls and outermost en- dozonal walls located at zooecial bend, composed of distinct U- to V-shaped laminae. Diaphragms and cys- tiphragms present in exozone, relative proportions sometimes quite variable both within and among zoar- ia. In general, zooecia having cystiphragms with at- tached diaphragms are less common than ones with all or nearly all diaphragms. Both diaphragms and cysti- Mean Mode S.D. No. Meas. No. Spec. 18 18 OLS 10 1 18 18 O15 10 1 .25 .25 021 8 1 25 25 021 8 1 .02 02 006 10 1 02 02 006 10 1 03 03 OOS 8 1 03 03 OOS 8 1 32 — 1.0 5 1 32 — 1.0 3 1 03 03 000 10 1 03 03 000 10 1 O1 O01 000 10 1 O1 O01 000 10 1 phragms fairly regularly spaced at approximately one- half zooecial cavity diameter. Exozonal diaphragms mainly inclined towards proximal side of zooecial tubes. Few perpendicular to walls. Many diaphragms curved convex outwards. Thickness usually constant throughout. Few diaphragms in outermost endozone numbering approximately three, found either perpen- dicular to wall or more commonly inclined slightly towards proximal side of zooecium and spaced at about one to one and one-half of a zooecial cavity diameter apart. Many cystiphragms gradually thicken towards side attached to wall. Commonly one to two diaphragms attached to each cystiphragm. Some with- out attached diaphragms. Mesozooecia uncommon. Tabulation closer and thickness slightly greater than for autozooecia, spacing approximately one mesozooe- cial cavity diameter apart. Cavity outlines subrounded to subangular. Some autozooecia develop into meso- zooecia and vice versa. Also found in maculae. Minute acanthostyles and/or mural lacunae observed in tan- gential section at many zooecial corners. Obscure in longitudinal section. In some colonies, more obvious than in others. Maculae distinct. Composed of larger autozooecia, thicker autozooecial walls, more meso- zooecia though still not common, generally larger acanthostyles (laminar sheaths) in some maculae. Measurements.—Measurements are summarized in Table 16. Remarks.—Specimens from the study area agree in all aspects with Ulrich’s (1893) description of Homo- trypa minnesotensis with the possible exception of somewhat thicker walls than depicted in Ulrich’s plate 19, figures 1-9. Perry (1962), studying specimens from the Upper Mississippi Valley, faced some diffi- MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH Table 16.—Quantitative data, Homotrypa minnesotensis Ulrich. See Key to Abbreviations, p. 33, for explanation. Character Range ZCD NL IV 30-43 (65-78) ..... 18—.27 CBIR 15ers Seas satsslesateersis .14-.21 CBRI26=14 5 eae eecccesten ce 17-.22 CBrlotall sits ecesescseseese 14—.22 OTA coreststororcce saisrorerainisteeitects 14-—.27 ZCD (mac) NL IV 30-43 (65-78) ..... 28-.38 GBi4 THIS) seiiees sess see .22-.32 GBR26—145| ee een ccecten ee .26—.34 GBitTotal soe csensewckececskecty 9 22-.34 LOMA, ie cane ccoee reesei .22-.38 ZWT NL IV 30—43 (65-78) ..... 02—.06 GBAIATS: shams acess ncnesoeees .04—.10 GB W262145) sieiscsecs sees es .04—.08 GBy otal! asc gs0. secre aceite .04—.10 TOTAL. 2%. « ficccseelsselsse ses .02—.10 ZWT (mac) NL IV 30-43 (65-78) ..... 05—.10 (2) 397. D7 Sy aeesaennecneaaaacecs .04—.10 CBM26=145 fe. ccessec wees .04—.08 CBRlotall esc cs ssecdeccrsee .04—.10 MOTAU ES 5 Soge coca et sot den dacs .04—.10 Z/mm? NL IV 30-43 (65-78) ..... 23-32 GBPS TS Freres sare tcoenker en 22-26 CBHI26—145 yeccseeccoeceee ee 23-24 CBeTotaleee oA sss. cciee eee 22-26 MOWAT yasoscdsctoeuer sce. 22-32 culty in whether to assign his specimens to H. min- nesotensis or H. exilis. Though many of his specimens displayed the larger branch diameters suggestive of the former species, the presence of thicker walls prompted him to assign the latter designation. Bork and Perry (1968b, p. 1048) note a similar close relationship be- tween the two species. Their specimens were assigned to H. exilis (their non-varietal form) because of ‘‘uni- form development of thick zooecial walls, lack of acanthopores, and extremely narrow peripheral re- gion,” although the peripheral region of H. minneso- tensis is noted by Ulrich (1893, p. 236) to be “‘very narrow.” In wall thickness, the species described here- in more closely resembles Homotrypa exilis; however, H. minnesotensis is distinguished by the presence of conspicuous maculae, acanthostyles, thin and wavy walls in endozone and larger diameter of colony branches. Additional differences between H. minne- sotensis and H. exilis encompass shape of zooecial cavity outlines (angular vs. rounded), curvature of zooecia (gentle throughout vs. abruptly bent peripheral region), relative amounts of mesozooecia (few vs. comparatively numerous), and obliquity of zooecial apertures (commonly oblique vs. direct), though these differences judging from Ulrich’s (1893) plate XIX would not seem to be as distinct as indicated in his text, a situation alluded to also by Bork and Perry 45 Mean Mode SD: No. Meas. No. Spec. PP) 21 021 725) 5 oll Z/ 17 020 15S 3 19 18 .0166 10 2 18 Ais nil .020 25 5 20 21 .028 50 10 oi) 34 028 25 5 Pall .26 030 10 2 30 30 .029 10 2 .28 .26, .30 .032 20 4 sil 30 .037 45 9 04 .03 013 25 5 07 06 016 15S 3 05 04 013 10 2, 06 06 .016 25 5 05 -05, .06 018 50 10 .O7 06 -013 25 5 08 .09 019 10 2 06 07 014 10 2 07 07 .O17 20 4 07 07 01S 45 9 28 26 2.8 8 5 24 24 1.6 3 23 23 0.58 3 2 24 24 ED 7 5 26 26 2:9 15 10 (1968b). Additionally, Ulrich’s plate XIX, figure 19 of H. exilis depicts acanthostyle-like features not noted in his text. A reexamination of Ulrich’s type material could serve to clarify the comparisons and discrepan- cies posed above. The overwhelming similarity to Ul- rich’s written description of H. minnesotensis, how- ever, suggests that the single major difference between his specimens and those of the present study area in Tennessee, namely exozonal wall thickness, could be environmentally controlled. Distribution.—Localities NL IV, CB. Studied Material.—Hypotypes NL IV 30(65)A-3- A(M) [USNM 431870], NL IV 43(78)B-6L-V(M) [USNM 431871], NL IV 43(78)B-6L-R(M) [USNM 431872], NL IV 43(78)B-5L-HH(M) [USNM 431873], NL IV 43(78)B-5L-JJ(M) [USNM 431874], NL IV 44(79)E-4-A [USNM 431875], NL IV 44(79)D-24L-R [USNM 431876], NL IV 63(98)B- 2LB-G [USNM 431877], NL IV 96(131)D-1-C [USNM 431878], CB 41B-2-B(M) [USNM 431879], CB 46A-2-A(M) [USNM 431880], CB 74—75A-5- A(M) [USNM 431881], CB 126A-1-B(M) [USNM 431882], CB 145C-4-D(M) [USNM 431883], CB 41B-8-A [USNM 431884], CB 45.5A-4-A [USNM 431885], CB 122A-18-B [USNM 431886], CB 145B- 2-B [USNM 431887], CB 161A-3-B(?) [USNM 431888]. 46 BULLETIN 353 Homotrypa flabellaris var. spinifera Bassler, 1903 Plate 5, Figures 1—6 Homotrypa flabellaris var. spinifera Bassler, 1903, p. 580, pl. 21. figs 11-15; Cummings, 1908, p. 847, pl. 18, figs. 2; Utgaard and Perry, 1964, p. 51-55, pl. 3. figs. 7, 8, pl. 4, figs 1-4 (partim). Description.—Zoaria ramose, sometimes encrust- ing. Zooecia initiated homogeneously throughout inner and outer endozone. Zooecial cavity outlines subpoly- gonal to subrounded in exozone. Endozonal zooecia polygonal. Zooecia commonly curve smoothly and rapidly from outer endozone, through inner exozone. Surface angle at or nearly at 90°. Sometimes zooecial bend in lower exozone. Endozonal walls even to wavy, commonly crenulate with occasional beading. Walls thicken fairly rapidly in lower exozone, sometimes be- coming quite thick, commonly pinch and swell slightly zooecially outwards, sometimes wavy. Walls formed of distinct U- to V-shaped laminae. Locally, apices of laminae joined by dark line. Exozonal diaphragms thin, generally consistent thickness throughout, usually planar but some slightly convex outwards, usually per- pendicular to zooecial walls but sometimes locally in- clined and overlapping. Diaphragms of many zooecia in endozonal/exozonal transition bend convex out- wards and inclined from the perpendicular towards the proximal sides of zooecia. Cystiphragm development generally occurs above these. Diaphragms in exozone spaced approximately two-thirds to one zooecial cavity diameter apart. Endozonal diaphragms planar, exceed- ingly thin, perpendicular to zooecial walls, subject to recrystallization. Diaphragms of upper endozone spaced apart one to two times zooecial cavity diameter. In inner endozone, spacing is two to three times zooe- cial cavity diameter. Cystiphragms present in most zooecia, usually found in exozone on distal side of curved portions of zooecia. Largest cystiphragms zooecially inwards. Cystiphragms of middle to upper exozone commonly thickest on upper side attached to wall, gradually thinning towards their bases. Cysti- phragms overlapping, locally isolated, commonly one or two diaphragms attached to each cystiphragm. Cys- tiphragms often fill one half zooecial cavity width in transverse section. Mesozooecia uncommon. When present, diaphragms thicker than for autozooecia and spaced approximately one mesozooecial cavity diam- eter apart. Acanthostyles variable in number across colony, sometimes scattered with several zooecia hav- ing no styles among them and other portions of colony having zooecia surrounded by two or three styles. Acanthostyles usually very large (including surround- ing laminar sheaths which are somewhat variable in diameter across zoaria), occur most commonly in exo- zone and less so in outer endozone. Endozonal styles commonly with surrounding petaloid arrangement of autozooecia. Maculae mainly composed of megazooe- cia and a few small mesozooecia. Vague indications of minute style-like openings suggested at many zooe- cial corners. Measurements.—Measurements are summarized in Table 17. Remarks.—Specimens assigned herein to Homotry- pa flabellaris vat. spinifera are characterized by their variably spaced and usually very large acanthostyles, widely spaced axial diaphragms, common pinching and swelling of moderately thick exozonal walls, gen- erally high surficial angles at approximately 90°, and commonly crenulate endozonal walls. H. flabellaris var. spinifera differs from H. subra- mosa in having granular to laminar exozonal walls, fewer acanthostyles which are larger and more vari- ably spaced, cystiphragms that commonly do not as extensively wrap around the perimeter of zooecial tubes, thicker exozonal zooecial walls, and smaller zooecial cavity diameters. H. flabellaris var. spinifera differs from H. tuber- culata in having less crowded diaphragms in the exo- zone, diaphragms within the endozone, fewer meso- zooecia, larger, fewer, and more variably spaced acan- thostyles, generally larger exozonal widths, and small- er zooecial cavity diameters with generally thinner zooecial walls. Bassler (1903, p. 580) noted the variety spinifera to accommodate forms of H. flabellaris Ulrich having “‘very large acanthopores.”’ Utgaard and Perry (1964) mentioned that their material contained specimens of Homotrypa with morphologies that continuously spanned the descriptions of H. flabellaris Ulrich and H. flabellaris var. spinifera Bassler. Consequently, they felt that both morphologies encompassed a single spe- cies group. Specimens within the present author’s study area possess larger styles in all instances. There- fore, Bassler’s varietal designation should be main- tained so as to not mask any possible ecophenotypic variation. Additionally, since specimens with large acanthostyles have until now been restricted to the Cincinnatian, the above distinction based on acantho- style size could also serve to enlighten phylogenetic relationships. Distribution.—Localities NL IV, CB, HCM, WB. Studied Material.—Hypotypes NL IV_ 100(135)A- 12L-J(M) [USNM 431889], NL IV_ 100(135)A- UNK.(M) [USNM 431890], NL IV 100(135)A-4L- BB(M) [USNM 431891], NL IV 100(135)A-4L- BBB(M) [USNM 4319892], NL IV 100(135)A-5L- C(M) [USNM 431893], NL IN 108(143)A-8-F(M) [USNM 431894], NL IV 108(143)A-11-B(M) [USNM 431895], NL IV 116(151)B-3-B(M) [USNM 431896], MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH 47 Table 17.—Quantitative data, Homotrypa flabellaris var. spinifera Bassler. See Key to Abbreviations, p. 33, for explanation. Character Range Mean Mode S.D. No. Meas. __No. Spec. ZCD IND LV i sere cele .10—.16 14 14 014 40 8 GB -eiseenes 12-18 a5) 16 .022 5 1 WB scasets fee: 16—18 si7/ aI) llts} .010 5 1 TOTAL... -L0—18 14 14 O18 50 10 ZCD (mac) NGI cet. o0a5 .16—.24 21 .22 021 35 7 GBi escent cis dans .22-.26 24 .24 014 5 i WB) ance sees .23-—.26 25 24, .26 .013 5 1 TOTAL is... .16—.26 21 .22 .025 45 9 ZWT INI NS aemendoe 03—.08 05 04 O13 40 8 CGBPrs tresses 04—.06 05 04 .008 5 1 WB aseeae ccna 02—.04 03 02 .008 5 1 IMOMVNG: caeonae 02—.08 05 04 O14 50 10 Z/mm? INEVIVoateeces 31-40 34 32 3.0 8 8 GBrisssctaseness 37 37 37 0.0 1 1 WIEBE risissacetseats 34 34 34 0.0 1 1 (ROWATS ect 31-40 34 32 2.9 10 10 AD (lam) INTE DW) sone ass .O5—.14 09 09 019 37 8 GB) eee 10—.14 11 10 .018 5 1 WB ice seecectlec .07—.08 08 .08 .004 5 1 TOTAU eee .05—.14 .09 08, .09 .020 47 10 AD (lum) INIEIDYA Séreneone .O1—.03 O01 Ol .006 31 8 (Cle eheacehepense O01 O1 O1 .000 4 1 WIBI irescacaner 02 .02 02 -000 4 1 INOHWNIES Aeaonce 01—.03 O01 Ol 006 39 10 ED (lam) INTE IW? 22) stele aes .10—.16 14 16 026 5) 1 (Ol 3 eeerceseaooce .O8—.12 11 12 018 5 1 WB icc: seine oo — —_ _ — — INONW NU Soocece .O8—.16 12 12 026 10 2 NL IV 50(85)A-2L-C [USNM 431897], NL IV 61(96)A-4-B [USNM 431898], NL IV 61(96)A-2-B [USNM 431899], NL IV 61(96)A-1-B [USNM 431900], NL IV 61(96)A-2-C [USNM 431901], NL IV 61(96)A-5-U [USNM 431902], NL IV 61(96)A-9-I [USNM 431903], NL IV 61(96)A-5-S [USNM 431904], NL IV 61(96)A-9-H [USNM 431905], NL IV 61(96)A-8-B [USNM 431906], NL IV 63(98)B- SLA-F [USNM 431907], NL IV 63(98)B-4LB-SS [USNM 431908], NL IV 63(98)B-3LB-S [USNM 431909], NL IV 63(98)B-3LB-U [USNM 431910], NL IV 63(98)B-6LA-F [USNM 431911], NL IV 72(107)B-S5L-A [USNM 431912], NL IV 72(107)B- 3L-A [USNM 431913], NL IV 72(107)A-4-B [USNM 431914], NL IV 85(120)A-5L-J [USNM 431915], NL IV 87(122)A-3B-A [USNM 431917], NL IV 93(128)A-7-A [USNM 431918], NL IV 93(128)A-1-L [USNM 431921], NL IV 93(128)A-6-A [USNM 431922], NL IV 93(128)A-1-M [USNM 431923], NL IV 93(128)A-5-E [USNM 431924], NL IV 94(129)A- 2L-G [USNM 431925], NL IV 94(129)A-3L-F [USNM 431926], NL IV 94(129)A-3L-E [USNM 431927], NL IV 96(131)B-2-C [USNM 431928], NL IV 96(131)B-1-A [USNM 431929], NL IV 96(131)B- 3-C [USNM 431930], NL IV 96(131)B-4-D [USNM 431931], NL IV 100(135)A-6L-E [USNM 431932], NL IV 100(135)A-10L-E [USNM 431933], NL IV 100(135)A-12L-G [USNM 431934], NL IV 100(135)A- 10L-G [USNM 431935], NL IV 100(135)A-5L-L=M [USNM 431936], NL IV 100(135)A-5L-E [USNM 431937], NL IV 100(135)A-3L-B [USNM 431939], NL IV 100(135)A-4L-H [USNM 431940], NL IV 100(135)A-6L-A [USNM 431941], NL IV 100(135)A- 2L-CC [USNM 431942], NL IV 100(135)A-9L-J [USNM 431943], NL IV 100(135)A-6L-B [USNM 431944], NL IV 100(135)A-9L-CCC [USNM 431945], NL IV 100(135)A-2L-R [USNM 431946], NL IV 100(135)A-9L-BB [USNM 431947], NL IV 100(135)A-2L-F [USNM 431948], NL IV 100(135)A- 9L-AA [USNM 431949], NL IV 100(135)A-4L-RR [USNM 431950], NL IV 100(135)A-11L-D [USNM 431951], NL IV 100(135)A-13L-C [USNM 431952], NL IV 100(135)A-6L-C [USNM 431953], NL IV 100(135)A-11L-E [USNM 431954], NL IV 100(135)A-4L-B [USNM 431955], NL IV 100(135)A- 11L-G [USNM 431956], NL IV 100(135)A-9L-LL [USNM 431957], NL IV 100(135)A-9L-RR [USNM 431958], NL IV 100(135)A-5L-B [USNM 431959], 48 BULLETIN 353 NL IV_ 100(135)A-4L-S [USNM 431960], NL IV 100(135)A-10L-F [USNM 431961], NL IV 100(135)A-4L-LL [USNM 431962], NL IV 100(135)A-10L-J_ [USNM 431963], NL IV 100(135)A-9L-PP [USNM 431964], NL IV 108(143)A-14-F [USNM 431965], NL IV 108(143)A-5-H [USNM 431966], NL IV 108(143)A- 6-L [USNM 431967], NL IV_ 108(143)A-17-H [USNM 431968], NL IV_ 108(143)A-6-M [USNM 431969], NL IV 108(143)A-16-D [USNM 431970], NL IV_ 108(143)A-12-C [USNM 431971], NL IV 108(143)A-2-I [USNM 431973], NL IV 108(143)A- 3-C [USNM 431974], NL IV 116(151)A-4-G [USNM 431976], NL IV 116(151)A-5-A [USNM 431977], NL IV 116(151)B-2-A [USNM 431978], NL IV 116(151)B-2-B [USNM 431979], NL IV 116(151)B- 3-A [USNM 431980], NL IV 117(152)A-7-R [USNM 431981], NL IV 61(96)A-6-L(F) [USNM 431982], CB 85A-14L-A(M) [USNM 431983], CB 50B-4-B [USNM 431984], CB 50A-3-B [USNM 431985], CB 67B-9-A [USNM 431986], CB 79A-2-A [USNM 431987], CB 85A-2-B [USNM 431988], CB 85A- 15L-A [USNM 431989], CB 85A-7-B [USNM 431990], CB 85A-17L-B [USNM 431991], CB 85A- 17L-D [USNM 431992], CB 120A-3-B [USNM 431993], CB 138B-2-A [USNM 431994], CB 153A- 2L-A [USNM 431995], CB 153B-1-B [USNM 431996], CB 156A-4L-C [USNM 431997], CB 45A- 7-A(F) [USNM 431998], CB 50A-4-B(F) [USNM 431999], CB 67B-8-D(F) [USNM 432000], CB 79A- 3-A(F) [USNM 432001], CB 79B-5-B(F) [USNM 432002], CB 85A-10-B(F) [USNM 432003], CB 85A- 4-A(F) [USNM 432004], CB 85A-13L-A(F) [USNM 432005], CB 122A-14-A(F) [USNM 432006], CB 122A-6-A(F) [USNM 432007], CB 153B-1-C(F) [USNM 432008], HCM 4(44)A-3-A [USNM 432009], HCM 38(77)A-1-G=H [USNM 432010], HCM 43(82)C-6-E,C [USNM 432011], HCM 43(82)C-4-A [USNM 432012], HCM 43(82)B-5-K [USNM 432013], HCM 43(82)C-1-D [USNM 432014], HCM 43(82)B-5-D [USNM 432015], HCM 43(82)C-5-O,P [USNM 432016], HCM 18(57)B-4-K(F) [USNM 432017], HCM 43(82)B-8-P(F) [USNM 432018], WB 44(56)B-2-A(M) [USNM 432019], WB 20(32)B-6-A [USNM 432020], WB 44(56)A-5-B [USNM 432021], WB 44(56)A-1-A [USNM 432022], WB 44(56)A-5-C [USNM 432023], WB 20(32)A-2-B(F) [USNM 432024]. Homotrypa similis Foord, 1883 Plate 7, Figure 3 Homotrypa similis Foord, 1883, p. 10; Ulrich, 1893, p. 242-243, pl. 20, figs. 28-33; Bassler, 1911, p. 185-187, figs 97-98; Bork and Perry, 1968b, p. 1052-1053, pl. 135, figs. 6-9. cf. Homotrypa similis Foord, 1883. Karklins, 1984, p. 128-130, pl. 5, fig. 2, pl. 6, figs. 1-4, 6; Fritz, 1957, p. 23, pl. 14, figs 4, 5. Description.—Zoaria ramose. Most zooecia initiated in outer endozone. In exozone, zooecial cavity outlines mainly subpolygonal to subrounded and elongate in tangential section due to low surface angle. In endo- zone, zooecial cavity outlines polygonal. Zooecia curve shallowly towards exozone and intersect surface at low angles (30° to 45°). In some specimens a slight zooecial bend occasionally found in lower exozone whereupon the zooecia will intersect the colony sur- face at somewhat higher angles than usual. Exozone narrow. Endozonal walls thin. Exozonal walls thicken slowly but continuously from base of exozone to col- ony surface. Zooecial walls appear granular in longi- tudinal section but in places exhibit convex outward laminae. Laminae more obvious in tangential section. Endozonal walls sometimes slightly crenulate in places, parallel-sided. Megazooecia present in center of endozone. Diaphragms common in outer endozone and exozone, occasionally present in some inner en- dozonal zooecia, fairly thin throughout and of even thickness, generally planar and fairly perpendicular to zooecial walls but sometimes inclined slightly. In ad- dition, some exozonal diaphragms gently convex or concave outwards or wavy. Locally, diaphragms some- times overlap, especially in outermost exozone of ma- ture specimens. Diaphragms of inner endozone spaced at about three zooecial cavity diameters apart, in outer endozone spaced about two zooecial cavity diameters apart, in inner exozone about one zooecial cavity di- ameter apart. Within the exozone, in general, spaced at two-thirds to one zooecial cavity diameter apart but locally sometimes much closer, especially in the outer exozone. Generally one or two diaphragms attach to a cystiphragm. Cystiphragms common throughout, gen- erally beginning in the outer endozone or inner exo- zone and continuing throughout the exozone. Cysti- phragms usually of even thickness, sometimes slightly thicker towards sides attached to zooecial walls. Cys- tiphragms overlap and in longitudinal section extend one-third to one-half the distance into the zooecial cav- ity. Cystiphragms in the outer endozone/inner exozone overlap the previously formed cystiphragm to a lesser extent than do later formed cystiphragms, and there- fore appear more elongate parallel to the zooecial axis. Locally, some cystiphragms overlap two other cysti- phragms in exozone. Usually one or two diaphragms attach themselves to a cystiphragm. Locally, however, no diaphragms appear to join them. Mesozooecia un- common in exozone. Diaphragms slightly thicker than for autozooecia and spaced at one mesozooecial cavity diameter apart. During ontogeny, either develop into MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH 49 Table 18.—Quantitative data, Homotrypa similis Foord. See Key to Abbreviations, p. 33, for explanation. Character Range Mean Mode S.D. No. Meas. No. Spec. MxZCD ND IW icsctesa: .18—.38 24 22, .24, .26 O50. 15 3 GBs fei scee ac .18—.34 .25 .24 .036 20 4 OMA -eeee .18—.38 Ps) .24 042 35 7 MnZCD INIERINY, cosoede .09-.16 13 12, .16 .024 15 3 G@Bixaecaececieee .09—.17 14 16 025 20 4 MOWAT Wrccee- .09—.17 13 16 024 85 7 ZWT INESDV one scete- .02—.06 .04 04 OLS 1S 3 (SIS ceaceeaanense .02—.05 .03 .03 009 20 4 TOTAL eee .02—.06 03 03 .012 35 7 Z/mm* NIL TV ssccess< 25-29 Zi — Zeal 3 3 CBs eiccscecess 24-27 25 24 1.4 4 4 MOTTA cs 24-29 26 24, 25 1.8 1 7 autozooecia or terminate. Acanthostyles present in exozone. Commonly two or three distinct styles sur- round each zooecium. Minute openings of uncertain nature sometimes observed in tangential section within zooecial walls. Laminae surrounding each style com- monly inflect into adjacent zooecial cavities and also commonly offset. Maculae present on megazooecia and some mesozooecia. Measurements.—Measurements are summarized in Table 18. Remarks.—Homotrypa similis characteristically has zooecia inclined at low angles to the colony surface, a granular appearance of most exozonal zooecial walls in longitudinal section, two to three acanthostyles per zooecium, axial megazooecia in the center of the en- dozone, diaphragms within both endozone and exo- zone, and uncommon mesozooecia. Homotrypa similis differs from H. minnesotensis, H. tabulata and H. tuberculata in having exozonal zooe- cia which are more inclined to the colony surface, and exozonal walls which appear granular in longitudinal section. It differs further from H. minnesotensis in lacking beading of endozonal walls and in having few- er inclined exozonal diaphragms, more endozonal di- aphragms, a less regular spacing of cystiphragms and diaphragms in the exozone, and thinner exozonal walls. H. similis differs additionally from H. tabulata in possessing many more cystiphragms, a less variable spacing of exozonal diaphragms, and more distinct acanthostyles. The present species differs further from H. tuberculata in having generally less rounded aper- tures, no distinct zooecial bend, no to few mesozooe- cia, less distinct styles, more regularly spaced dia- phragms and cystiphragms, and generally thinner ex- ozonal zooecial walls. The presence of thin inner endozonal diaphragms is suggested to be obscured in some specimens due to recrystallization. In H. tabulata, endozonal dia- phragms, in places, were observed to be in various stages or recrystallization so that in the most extreme case entire diaphragms could have been obliterated. Bork and Perry (1968b) noted that one of their four specimens of H. similis similarly lacked diaphragms in its inner endozone, however, they did not offer an ex- planation for this phenomenon. Distribution.—Localities NL IV, CB, HCM. Studied Material.—Hypotypes NL IV 108(143)A-8- D(M) [USNM 432025], NL IV_ 108(143)A-3-B(M) [USNM 432026], NL IV 108(143)A-6-N(M) [USNM 432027], NL IV 94(129)A-4L-E [USNM 432028], NL IV 100(135)A-10L-D [USNM 432029], NL IV 116(151)A-5-F [USNM 432031], CB 46A-3-A(M) [USNM 432032], CB 50A-2-B(M) [USNM 432033], CB S50A-2-C(M) [USNM 432034], CB 50A-2-A(M) [USNM 432035], CB 50A-3-D [USNM 432036], CB 50A-3-C [USNM 432037], CB S50A-2-E,F [USNM 432038]. Homotrypa tabulata, new species Plate 6, Figure 3 Description.—Zoaria ramose. Budding of new zooecia occurs between mid- to outer endozone. Zooe- cia curve broadly to colony surface and intersect it at between 50° and 70°. Sometimes a slight zooecial bend in lower exozone. In tangential section, zooecial cavity outline subrounded to subpolygonal and commonly slightly elongate parallel to colony axis due to low surface angle. Polygonal outline in endozone. Endo- zonal walls thin, thicken gradually in lower exozone before reaching maximum thickness which itself is thin. Exozonal walls laminate, composed of V-shaped laminae. Some walls with dark line connecting apices of laminae. Endozonal walls even to slightly crenulate, fairly parallel-sided. Endozonal zooecia larger in di- ameter than exozone. Constricted at exozonal base. Endozonal diaphragms planar, perpendicular to zooe- 50 BULLETIN 353 Table 19.—Quantitative data, Homotrypa tabulata n. sp. See Key to Abbreviations, p. 33, for explanation. Character Range Mean ZCD CB 41-SO ....... .16—.24 19 (C@Bml22 weegsceces: .20—.22 Dl GB totals... .16—.24 19 HOM ease 14-18 16 ION G cpasoncadc .14—.24 .19 ZWT CB 41-SO ....... .03—.04 03 (GBYI226.5)9.8ee .02—.03 02 (GB Motaleme case .02—.04 03 HEM: Ararctess .03—.04 03 ANOPUN Creaepanecoe .02—.04 03 Z/mm? CB 41-SO ....... 28-35 31 (GBD a aeseeses 28 28 EB iotallyee- eee 28-35 30 HEM iameee seer “= -- DOTA rte sect 28-35 30 AD (lam) CB 41-SO ....... .02—.05 04 CBHI 22R eters .05—.06 05 G@Bifotall 35.2e--- .02—.06 04 HIG Migs i ea-ceeee .02—.03 03 TOTAW errs: .02—.06 04 Mode S.D. No. Meas. No. Spec. 18 .020 15 3 P22 O11 5 1 20 020 20 4 —_ O16 5 1 18, .20 .024 25 5 03 005 15 3 .02 004 5 1 03 007 20 4 03 006 5 1 03 007 25 5 — 5.0 2) 2 28 0.0 1 1 28 4.0 3 3} 28 4.0 3 3 04 O11 15 3 05 006 5 l 04 O13 20 4 03 006 5 1 04 O13 25 5 cial walls, thin. Spaced two zooecial cavity diameters apart. Usually consistent in thickness, but some slight- ly thicker. Diaphragm spacing decreases to about one zooecial cavity diameter at endozonal/exozonal tran- sition. Diaphragms of exozone perpendicular to zooe- cial walls to slightly inclined from perpendicular to- wards proximal side of zooecia, commonly curved slightly, being convex zooecially outwards. Dia- phragms occasionally cystose and overlapping. Dia- phragms spaced at one-third to one-half of a zooecial cavity diameter apart. Minute acanthostyles with small laminar sheaths present at zooecial corners and be- tween zooecia. Four to six surround each zooecium. Some styles of lower exozone offset in zooecial cavity. Some styles of upper exozone offset within walls, less commonly inflect into zooecial cavity. Maculae com- posed of megazooecia and of mesozooecia. Dia- phragms of mesozooecia perpendicular to wall, spaced at one mesozooecial cavity diameter apart. Some change into autozooecia. Etymology.—tThe trivial name refers to the abun- dance and relatively close tabulation of autozooeciai diaphragms. Measurements.—Measurements are summarized in Table 19. Remarks.—Specimens assigned to Homotrypa ta- bulata have subrounded to subpolygonal zooecial cav- ity outlines, surficial angles of between 50° and 70°, relatively wide endozooecial tubes with even to cren- ulate walls, endozonal diaphragms spaced at about two zooecial cavity diameters apart, exozonal diaphragms commonly curved outwards, perpendicular to inclined to zooecial walls, and spaced at between one-third and one-half of a zooecial cavity diameter, and four to six minute acanthostyles surrounding each zooecium. Homotrypa tabulata is quite similar to Homotrypa exilis variant B of Bork and Perry (1968b, p.1049) but for the presence of definitive acanthostyles (they note that true acanthostyles are ‘“‘probably lacking” but could be present and represented as dark spots at iso- lated wall junctions as viewed in tangential section), diaphragms in the endozone, and somewhat smaller zooecial cavity diameters. H. tabulata differs from Homotrypa minnesotensis Ulrich, 1886 as well in the presence of endozonal diaphragms and smaller zooe- cial cavity diameters, and also by the absence of nu- merous exozonal cystiphragms. See the Remarks sec- tions of Homotrypa exilis (typical form and two vari- ants) as found in Bork and Perry (1968b) as well as the Remarks section of H. minnesotensis described herein (p. 44) for discussions contrasting and compar- ing A. exilis with H. minnesotensis. A few endozonal diaphragms were observed to be in various stages of recrystallization so that, in places, entire diaphragms are suggested to have been re- moved. Distribution.—Localities CB, HCM, WB. Studied Material.—Holotype CB S50A-4-A(M) [USNM 432039], Paratypes CB 41A-3-B(M) [USNM 432040], CB 41B-4-B(M) [USNM 432041], CB 122A-10-A(M) [USNM 432042], HCM_ 11(50)B-1- MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH Sil E(M) [USNM 432043], HCM 11(50)A-5-I [USNM 432044]. Homotrypa tuberculata Ulrich, 1893 Plate 7, Figures 1—2 Homotrypa tuberculata Ulrich, 1893, p. 240-241, fig. 14. Description.—Zoaria ramose. Most zooecia budded in outer endozone. In exozone, zooecial cavity outline subrounded to rounded. In endozone zooecial cavity outline polygonal. Zooecia curve gently from early en- dozone to inner exozone. Sharp zooecial bend in lower exozone. Zooecia then continue directly outwards to intersect colony surface at right angles. Exozone gen- erally short. Walls thicken slightly in inner exozone. Greater thicknesses occur above zooecial bend. En- dozonal walls thin. Exozonal wall microstructure com- posed of convex V-shaped laminae. Zooecial walls in endozone fairly parallel-sided, even to slightly crenu- late, locally wavy. Axial megazooecia in central en- dozone. Diaphragms present in outermost endozone and exozone. In exozone, diaphragms extremely vari- able in number. Spacing varies from one-fifth to two- thirds of a zooecial cavity diameter. Thicknesses vary between individual diaphragms. Diaphragms variable in orientation being planar and perpendicular to zooe- cial walls, to inclined, commonly overlapping. Dia- phragms sometimes wavy, or cystose or bulge concave to convex outwards. Commonly one to three flat dia- phragms mainly perpendicular or nearly so to walls before zooecial bend. Overlapping cystiphragms pres- ent in exozone beginning at the zooecial bend. Found mainly on distal side of zooecium. Variable in number. Thickness varies between individual cystiphragms. Single cystiphragms frequently overlap two others. In longitudinal section, cystiphragms commonly extend one-half to two-thirds of a zooecial cavity diameter into zooecial void, but sometimes greater, especially at zooecial bend. Mesozooecia scattered throughout col- ony. Small polygonal cavity outline. Diaphragms thicker than for most autozooecia, spaced one to one and one-half mesozooecial cavity diameters apart. Budding initiated in exozone. Where exozone is rela- tively wide, mesozooecia terminate and zooecial cavity outlines become subrounded to subpolygonal. Acan- thostyles common, distinct, usually three to five sur- rounding each zooecium and located at zooecial cor- ners and between zooecia in the exozone, clearly ob- served in longitudinal section as clear calcitic rods. Acanthostyle walls commonly inflect autozooecial walls where thin, and sometimes inflect in outer exo- zone where walls thicken. Some offset and inflecting. Styles almost always originate at zooecial bend. Mac- ulae composed of megazooecia. Specimens commonly show rejuvenated growth within a portion of the exozone. Initially walls are thin with thin planar diaphragms spaced at two-thirds of a zooecial cavity diameter apart before assuming more typical exozonal morphology. Measurements.—Measurements are summarized in Table 20. Remarks.—H. tuberculata typically has subrounded to rounded zooecial cavity outlines, zooecia perpen- dicular to the colony surface, a zooecial bend in the lower exozone, a variable spacing of autozooecial di- aphragms which are often quite closely spaced, me- sozooecia, commonly three to five acanthostyles around each autozooecium, and a short exozonal width. It differs from Homotrypa flabellaris var. spinifera in having a generally narrower exozone with more variably oriented and more closely spaced diaphragms, no diaphragms within the inner endozone, more com- mon mesozooecia, smaller, more common and more regularly spaced acanthostyles, larger zooecial cavity diameters and generally thinner zooecial walls. Specimens assigned to H. tuberculata differ from Ulrich’s (1893) original species description in possess- ing a greater number of acanthostyles. Ulrich’s (1893) figure 14c, however, suggests that more styles could be present than alluded to in his text. Until a thorough reexamination of Ulrich’s type material is made, how- ever, the present specimens will retain their current designation due to their otherwise overall morpholog- ical similarity with Ulrich’s description. Distribution.—Localities NL IV, CB, HCM. Studied Material.—Hypotypes NL IV 108(143)A-4- E(M) [USNM 432045], NL IV 72(107)B-4L-C [USNM 432046], NL IV 72(107)B-3L-B [USNM 432047], NL IV 85(120)A-9L-C [USNM 432048], NL IV 85(120)A-6L-A [USNM 432049], NL IV 87(122)A-6B-B [USNM 432050], NL IV 87(122)A- 6A-H [USNM 432051], NL IV 93(128)A-1-K [USNM 432052], NL IV 93(128)A-2-C [USNM 432053], NL IV 94(129)A-4L-F [USNM 432054], NL IV 96(131)B-3-B [USNM 432055], NL IV 100(135)A- 12-D [USNM 432056]. NL IV 100(135)A-11-F [USNM 432057], CB 85A-6-C,D(M) [USNM 432058], CB 41B-3-A [USNM 432059], CB 41B-2-C [USNM 432060], CB 41B-7-A [USNM 432061], CB 72C-7L-A [USNM 432062], CB 74—75A-1-A [USNM 432063], CB 82A-3-B [USNM 432064], CB 132C- 9-A [USNM 432065], CB 149A-4-A [USNM 432066], CB 156A-4L-A [USNM 432068], CB 161A- 2-D [USNM 432069], CB 161A-4-B [USNM 432070], CB 41B-2-D(F) [USNM 432071], CB 50A-2-D(F) [USNM 432072], CB 67B-11-B(F) [USNM 432073], CB 72A-3L-B(F) [USNM 432074], CB 120A-6-A(F) BULLETIN 353 Table 20.—Quantitative data, Homotrypa tuberculata Ulrich. See Key to Abbreviations, p. 33, for explanation. Character Range Mean Mode S.D. No. Meas. No. Spec. ZCD INDES IN Seanpccee .18-.22 20 20, .22 O17 5 1 CB peckrmcttersce .20—.22 21 20, .22 -.010 5) 1 HEM eens .12—.23 18 18 .022 40 8 TOTAW seer .12—.23 18 18 024 50 10 ZWT IND OY/ Soansoode .02—.03 .02 .02 .006 5 1 CB) 3 scsnesaeeds -03—.04 03 03 .006 5 1 HIGM) cae bcceis .02—.07 04 04 .012 40 8 MOWAW eee .02—.07 .04 .04 013 50 10 Z/mm-? INI AY, Gapaaeode 23 23 23 0.0 1 1 By asic sntasiass — -= i — — — HIEMe eateries 24-29 26 i 1.9 5 5 TOTAL c-css 23-29 26 = Xp) 6 6 MxMCD INTEL) Se ocnsaec .O5—.10 07 .06 020 5 1 GBh assncseseiasins .O7—.12 09 10 020 > 1 ICG Soossascac .04—.17 08 .08 .027 37 8 TOTAL eis .04—.17 08 .08 026 47 10 MnMCD INIESINY SanerBeoe OS—.08 .06 06 O11 5 1 CBr sescecte: O5—.06 06 .06 004 5 1 FIC Ma ranaaeserts 02—.08 05 05 016 37 8 INOW, Saogooe 02—.08 05 05 O1S 47 10 AD (lam) INDERIOWY ‘Scacnbons .06-.07 07 07 .006 >) 1 (Ole anonaapadaeon .06—.07 06 .06 .006 5 1 IGM ieee seccre 03-.07 OS OS O10 40 8 MOWAT were. 03—.07 OS 05 O11 50 10 [USNM 432075], CB 120A-7-B(F) [USNM 432076], CB 149A-2-A(F) [USNM 432077], HCM 5(44)A-2- A(M) [USNM 432078], HCM 18(57)B-6L-H(M) [USNM 432079], HCM 43(82)B-8-Q(M) [USNM 432080], HCM 43(82)B-7-L(M) [USNM 432081], HCM 43(82)B-4-G(M) [USNM 432082], HCM 43(82)C-4-B(M) [USNM 432083], HCM 43(82)B-7- B(M) [USNM 432084], HCM 43(82)C-3-DD(M) [USNM 432085], HCM_ 18(57)B-4-D [USNM 432086], HCM 18(57)B-5-B [USNM 432087], HCM 43(82)C-3-S [USNM 432088], HCM 43(82)C-4-J [USNM 432089], HCM 18(57)B-4-H(F) [USNM 432090], HCM 43(82)C-3-N(F) [USNM 432091], HCM 43(82)A-2-C(F) [USNM 432092], HCM 43(82)C-5-J(F) [USNM 432093], HCM 43(82)B-4- C(F) [USNM 432094]. Homotrypa callosa Ulrich, 1893 Plate 8, Figures 1—2 Homotrypa callosa Ulrich, 1893, p. 243-244, pl. 20, figs. 15-21. Description.—Zoaria ramose. Zooecia budded throughout colony. Zooecial cavity outline in tangen- tial section subrounded to subpolygonal. In endozone polygonal. Zooecia curve evenly from outer endozone to colony surface. Surface angle varies mainly from 80° to 90°. Slight zooecial bend sometimes in lower exozone. Walls thicken gradually in outermost endo- zone and lowermost exozone and generally remain of constant thickness zooecially outwards. Sometimes thicken and thin. Walls mainly granular, in few places poorly defined U-shaped laminae (particularly in lon- gitudinal section). Endozonal walls parallel-sided, even. Diaphragms in exozone perpendicular to zooe- cial walls, planar, spaced one-half to two-thirds of a zooecial cavity diameter apart. Along colony axis, di- aphragms spaced two to three zooecial cavity diame- ters apart. Near endozonal/exozonal transition one zooecial cavity diameter apart. Zooecia mainly have both diaphragms and overlapping cystiphragms. Some zooecia with diaphragms only. Cystiphragms extend across one-half to two-thirds of a zooecial cavity di- ameter except near bottom of exozone where greater. Commonly one diaphragm, sometimes two, attached to each cystiphragm. Zooecially innermost surface of cystiphragm (‘‘inner edge”’ of Ulrich, 1893, p. 243) commonly relatively straight across zooecium. Meso- zooecia rare in non-macular areas. Styles present in exozone but scattered and very inconspicuous. Ob- scure in longitudinal section. Maculae composed of megazooecia and some mesozooecia. Subrounded to subangular cavity outline. Diaphragms spaced at one mesozooecial cavity diameter apart, slightly thicker than for autozooecia. Measurements.—Measurements are summarized in Table 21. MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH 3) Table 21.—Quantitative data, Homotrypa callosa Ulrich. See Key to Abbreviations, p. 33, for explanation. Character Range Mean Mode S.D. No. Meas. No. Spec. ZCD NGL sence .10—.17 14 aS .024 20 2 TOWN cosas .10-.17 14 ail) .024 20 2 ZCD (mac) INE LV) esas .19-.31 25 .24 .027 20 2 TODA? 222.2%: -19-.31 “25 .24 .027 20 2 ZWT INTE DVgeesetctast .03—.08 .06 -05 .016 20 2 TOWA, © cecen- .03-.08 .06 05 016 20 2 ZWT (mac) INIGADVeccisrenene .03—.06 05 04, .05 008 20 2 WORAT eens: .03—.06 05 .04, .05 008 20 2 Z/mm? INDE IN/ Coaobisciee 34 34 34 0.0 3) 2 OWA eee -= 34 34 34 0.0 3 2 MCD NELV access 02-.04 .03 .02 .008 10 1 AKOIVNE, oasador 02—.04 .03 02 .008 10 1 Remarks.—H. callosa is characterized by smoothly curving zooecia that intersect the colony surface at or nearly at 90°, the presence of diaphragms within the entire endozone and exozone, a generally granular zooecial wall structure, few, scattered and inconspic- uous acanthostyles, and relatively small zooecial cav- ity diameters. H. callosa differs from Homotrypa subramosa in having fewer and much less conspicuous acantho- styles, smaller zooecial cavity diameters, thicker zooe- cial walls, and a somewhat more prevalent granular zooecial wall structure. H. callosa differs from H. minnesotensis in that the former species has an endozone in which the walls are non-crenulate and non-beaded and in which dia- phragms are present throughout. Exozonal walls are largely non-laminar and thicker. Also, within a smaller zooecial cavity are relatively more cystiphragms and less inclined diaphragms. Distribution.—Locality NL IV. Studied Material.—Hypotypes NL IV 96(131)B-2- J(M) [USNM 432095], NL IV 100(135)A-13L-F(M) [USNM 432096]. Homotrypa subramosa Ulrich, 1896 Plate 9, Figures 1—5 Homotrypa subramosa Ulrich, 1886, p. 81; 1893, p. 239, 240, pl. 19, figs. 21-28; Bassler, 1911, p. 187-189, text-figs. 99, 100; Bork and Perry, 1968b, p. 1053-1055, pl. 136, figs. 1-3. Description.—Zoaria mainly ramose, some encrust- ing. Budding of zooecia occurs throughout endozone. In exozone, zooecial cavity outline subpolygonal. In endozone, outline polygonal. Zooecia curve smoothly and evenly from endozone to reach colony surface at right angles. No distinct zooecial bend. Exozone be- gins within the curved portion of zooecial tubes before zooecia attain orientation at right angles to colony sur- face. Walls thicken gradually in lowermost exozone, maximum thickness in exozone only moderate. Exo- zonal walls sometimes thicken and thin slightly along length. Walls granular to laminar, laminae more obvi- ous in tangential section. In endozone, zooecial walls fairly parallel-sided, even to crenulate. Walls some- times thicken slightly and accommodate short acan- thostyles. Diaphragms present throughout endozone where thin, planar, perpendicular to zooecial walls and commonly spaced three or more zooecial cavity di- ameters apart within inner endozone and about one and one-half zooecial cavity diameters apart in outer en- dozone. Diaphragms of innermost endozone occasion- ally sparse in some zoaria, when present, commonly associated in zones. Some diaphragms possibly oblit- erated due to recrystallization. Diaphragms present throughout exozone. Commonly thin, sometimes rel- atively thick, forming distinct zooecial wall lining units and associated with slight thickening of wall, mainly planar and perpendicular to zooecial walls but sometimes inclined, slightly curved and incomplete (overlapping). Spacing commonly between one-half to two-thirds of a zooecial cavity diameter apart but lo- cally spaced closer or less frequently further. Cysti- phragms present in exozone, overlapping, and fairly regularly spaced. In longitudinal section, cystiphragms most commonly found in zoarially distal side of zooe- cial tube. Maximally extend one-half of a zooecial cav- ity diameter into zooecial cavity and wrap around two- thirds to three-fourths of zooecial perimeter. Some in- dividual cystiphragms differ slightly in thickness be- tween each other. Within single cystiphragms, gradations in thickness can exist with the top of the cystiphragm being thicker than the bottom, the thick- ness variation being continuous and gradual. Thicker walled cystiphragms commonly associated with slight thickening of zooecial wall. In lowermost exozone, 54 BULLETIN 353 Table 22.—Quantitative data, Homotrypa subramosa Ulrich. See Key to Abbreviations, p. 33, for explanation. Character Range Mode S.D. No. Meas. No. Spec. ZCD INDUFIING ascoonpeno6doo .22—.28 .24 22 026 5 1 (GV3)) gresadaconupapobec .18—.24 21 .20 020 15 3 In(CMM I coseptoasoacacce 20—.26 23 24 O19 15 3 WEB ieaccesacistsisciitis .20—.25 22 .22 O1S 15 3 WESD- Total! -tesc-c- 20—.26 .23 22 O17 30 6 TOTAL ea cneeeiiae cs .18—.28 22 22 021 50 10 ZCD (mac) INDE IN seapoacnpcagce 30—.34 32 O14 5 1 (C)2) covandscoobannontt .24—.28 28 O18 5 1 JRCCM | Qoencodanndoanoc .26—.30 .26 O18 10 2) WIB Mouse seniseleisiee ) 1 (Cl). Sosbadonbebaccoaes OS—.08 06 O11 15 3 IEKCIML pagecanoooneboan OS—.08 07 009 ilS) 3 WIB) actatancrionncinee'ss .06—.08 06, .07 006 1S 3 WES Totalia-e sc. 05—.08 07 008 30 6 DKOPYN Ly Seessoseeasen OS—.08 06 009 50 10 AD (lum) INBEV cc cemicicisecias O1 — — — 1 (C)2)e SesseneeeebseeoneE Ol — -- — 3 [RIO croapodcccaonase 01 — — — 3 N05), oascoonposoneasoon .O1—.02 — — — 3 WEST Total’... ...: O1—.02 — = — 6 TKOMYNE, Gonsanoocoode .01—.02 — — —_ 10 where zooecia bend, cystiphragms usually larger than normal, extending farther into zooecial cavity. In gen- eral, each cystiphragm has an accompanying dia- phragm attached between it and the zooecial wall. Some cystiphragms have two diaphragms, however, while others have none. Mesozooecia absent to rare. Acanthostyles common throughout exozone. Found mainly at zooecial corners but sometimes found be- tween two zooecia. Two to four styles surround each zooecium, commonly two to three. Laminar sheaths sometimes inflect into zooecial cavities, depending on the wall thicknesses of the autozooecia. Isolated short styles sometimes found in endozone commonly asso- ciated with former presumed growth surface (i.e., at a surface of rejuvenation). Maculae present and consist of megazooecia. In many low encrusting forms, walls thinner, acanthostyles with narrower laminar sheaths, and commonly three to five styles surround each zooe- cium. Zooecial cavity diameter near base somewhat smaller. Measurements.—Measurements are summarized in Table 22. Remarks.—Specimens assigned to H. subramosa typically have zooecia that curve smoothly and evenly to intersect the colony surface at right angles, dia- phragms generally found throughout colony (though some zoaria have sparse diaphragm development in inner endozone), commonly two to three distinct acan- thostyles around each zooecium, relatively large zooe- cial cavity diameters, and cystiphragms which com- monly wrap around a large portion of zooecial perim- eter. Homotrypa subramosa differs from H. callosa in the presence of common and distinct acanthostyles, larger MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH Sp) zooecial cavity diameters, and thinner walls, and a more widespread development of a laminar wall struc- ture. Distribution.—Localities NL IV, CB, HCM, WB. Studied material.—Hypotypes (RAMOSE FORMS): NL IV_ 116(151)A-3-M (M) [USNM 432097], NL IV 87(122)A-2B-A [USNM 432098], NL IV 93(128)A-10-G [USNM 432099], NL IV 93(128)A-9-G [USNM 432100], NL IV 96(131)B-4-F [USNM 432101], NL IV 96(131)B—D [USNM 432102], NL IV 96(131)C-3-E [USNM 432103], CB 82B-3-A (M) [USNM 432105], CB 82A-2-A (M) [USNM 432106], CB 132B-4-B (M) [USNM 432107], CB 41A-5-B [USNM 432108], CB 62A-5-C [USNM 432109], CB 82A-3-A [USNM 432110], CB 82A-4-A [USNM 432111], CB 85B-1-A [USNM 432112], CB 145B-1-D [USNM 432113], CB 153A-4L-C [USNM 432114], CB 116A-4-A [USNM 432115], CB 45A-9- A(F) [USNM 432116], CB 46B-2-A(F) [USNM 432117], CB 54A-2-A(F) [USNM 432118], CB 55A- 1-A(F) [USNM 432119], CB 55B-1-B(F) [USNM 432120], CB 70A-4-A(F) [USNM 432121], CB 85A- 6-A(F) [USNM 432122], CB 114A-5-B(F) [USNM 432123], CB 114A-4-A(= 5-A)(F) [USNM 432124], CB 114A-13-A(F) [USNM 432125], CB 128A-1-A(F) [USNM 432126], HCM 18(57)B-4-E(M) [USNM 432127], HCM 18(57)B-4-F(M) [USNM 432128], HCM 43(82)B-8-U(M) [USNM 432129], HCM 18(57)B-4-A,B [USNM 432130], HCM 18(57)B-3-A [(USNM 432131], HCM 18(57)B-4-G [USNM 432132], HCM 38(77)B-2A-A [USNM 432133], HCM 43(82)A-3-S [USNM 432134], HCM 43(82)B- 5-B [USNM 432135], HCM 11(50)A-5-A(F) [USNM 432136], HCM_ 11(50)B-1-D(F) [USNM 432137], HCM 11(50)B-6-N(F) [USNM 432138], HCM 11(50)B-6-A(F) [USNM 432139], HCM 11(50)B-2- B(F) [USNM 432140], HCM 11(50)A-6-J(F) [USNM 432141], HCM 18(57)A-5L-A(F) [USNM 432142], HCM 43(82)A-8-W(F) [USNM 432143], HCM 43(82)A-2-B(F) [USNM 432144], HCM 43(82)C-3- M(F) [USNM 432145], HCM 50(89)A-5-M(P) [USNM 432146], WB 43(55)C-S5L-A(M) [USNM 432147], WB 44(56)B-3-A(M) [USNM 432148], WB 44(56)C-2-C(M) [USNM 432149], WB 2(14)A-2-A [USNM 432150], WB 29(41)A-2-A [USNM 432151], WB 41(53)D-2-A [USNM 432152], WB 27(39)B-8- A(P) [USNM 432153], WB 29(41)A-6-A(F) [USNM 432154], WB 43(55)B-1-A(F) [USNM 432155], WB 43(55)B-4-A(F) [USNM 432156], WB 43(55)B-2- B(F) [USNM 432157], WB 44(56)A-3-A(F) [USNM 432158], WB 44(56)B-5-A(F) [USNM 432159], WB 44(56)B-5-C(F) [USNM 432160], WB 44(56)A-4- A(F) [USNM 432161]. (ENCRUSTING FORMS): NL IV 24(59)B-3-A [USNM 432162], NL IV 24(59)B- 3-B [USNM 432163], NL IV 33(64)A-2-B [USNM 432164], NL IV 43(78)B-6L-BB [USNM 432165], NL IV 44(79)E-4-B [USNM 432166], NL IV 50(85)A- 11-C [USNM 432167], NL IV 87(122)A-6A-A [USNM 432168], CB 55A-10-A [USNM 432169], CB 138B-7-A [USNM 432170]. Homotrypa sp. A Plate 8, Figure 3 Description.—Zoaria ramose. Zooecial cavity out- lines in exozone subpolygonal to subrounded where walls thick, subpolygonal to polygonal where walls thin. Zooecia curve smoothly from outer endozone to colony surface. Zooecial bend sometimes in lower exozone. Surface angle at or nearly at 90°. Endozonal walls thin, thicken relatively quickly in outer endo- zone, characteristically thick in inner exozone, then thin somewhat in outer exozone. Wall microstructure of U-shaped laminae convex outwards. Faint dark line sometimes observed to connect apices of laminae. En- dozonal walls uneven, wavy, crenulate, and/or beaded in places. Megazooecia in inner endozone. Endozone relatively wide. Diaphragms in exozone planar to curved convex outwards, commonly inclined towards proximal part of colony. Sometimes perpendicular to zooecial walls, overlapping, associated with cysti- phragms, or less commonly wavy. Some individual di- aphragms thickened especially where adjacent walls maximally thickened. Spacing variable, often between one-half and two-thirds of a zooecial cavity diameter apart. Diaphragms in outermost endozone usually pla- nar and perpendicular to zooecial walls, becoming more inclined and curved towards exozonal base. Spacing varies between one and three zooecial cavity diameters apart with spacing decreasing towards exo- zone. Diaphragms uncommon in inner endozone. Some cystiphragms present in exozone only and on distal sides of zooecia, frequently gradational with cys- tose diaphragms, sometimes with attached diaphragm. Mesozooecia absent. Acanthostyles in exozone be- tween zooecia and at zooecial corners. Commonly two to three surround each zooecium. Laminar sheaths larger where surrounding zooecial walls thicken, 1n- flect zooecial tubes where walls thin, less commonly where walls thick. Some offset. Occasional styles in endozone. Measurements.—Measurements are summarized in Table 23. Remarks.—Homotrypa sp. A is morphologically distinct from other species of the study area and is unlike any other previously described in the literature owing primarily to the exceedingly robust develop- ment of laminar, irregularly thickened exozonal walls. Other typical features of this species include a gener- 56 BULLETIN 353 Table 23.—Quantitative data, Homotrypa sp. A. See Key to Abbreviations, p. 33, for explanation. Character Range Mean ZCD INTE DV 9 seetactcier .08—.15 alli AKONIUNG, Banoscne .O8—.15 siti ZWT IN GAINS eecosdece .08—.14 all MORAY ea ee .08—.14 Sil AD (lam) INDE AINA! peoasenbe .O5—.12 08 AOU, Goneqase .O5—.12 08 ally smooth zooecial curvature with a surficial angle at or nearly at 90°, occasional irregular development of endozonal walls (uneven, wavy, crenulate, and/or beaded), common inclined and cystose diaphragms, two to three acanthostyles around each exozonal zooe- cium, and endozonal megazooecia. Homotrypa sp. A differs from Homotrypa minne- sotensis in its wider and unevenly thickened exozonal walls, slightly higher surficial angle, smaller zooecial cavity diameter, and presence of distinct acanthostyles. Due to the limited material at hand, a formal species designation is not opted at this time. Distribution.—Locality NL IV. Studied material.—Hypotypes NL IV_ 100(135)A- 10L-O(M) [USNM 432171], NL IV 108(143)A-14- N(M) [USNM 432172]. Genus MONTICULIPORA d ’Orbigny, 1850 Type species.—Monticulipora mammulata d’Orbigny, 1850, p. 25. Monticulipora sp. A Plate 10, Figures 1—3 Description.—Zoarium encrusting. Zooecial cavity outlines subpolygonal. Zooecial walls generally gran- ular, sometimes with poorly defined laminae, thin, ir- regularly thickened and thinned. In places, suggestions of dark median line within walls. Cystiphragms over- Mode S.D. No. Meas. No. Spec. 10 026 15 2 10 026 15 2 alii 021 15 2 lal 021 15 2 .07, .08, .10 -020 15 2 .07, .08, .10 020 15S 2 lapping. In more submature portions of zooecia, cys- tiphragms tend to protrude further into the zooecial cavity than the less inflated cystiphragms found in more peripheral regions of the colony. Zooecially out- ward cystiphragms not only wrap around a larger por- tion of each zooecial tube than the inner ones, but also are more overlapping, commonly with between 12 to 14 cystiphragms per mm instead of six to eight. Each of the more inflated cystiphragms usually with an as- sociated planar diaphragm. Relatively fewer dia- phragms in outer portions of zooecia with no or one diaphragm associated with each cystiphragm. Meso- zooecia absent to rare. Acanthostyles in exozone, small, found within more robust portions of otherwise thin walls, difficult to distinguish in longitudinal sec- tion, found at zooecial corners or between zooecial tubes, offset or centered and inflecting adjacent zooe- cial tubes especially in deep tangential section, com- monly four to six surround each zooecium. Zooecial walls and acanthostyle laminar sheaths somewhat more thickened in macular areas. Measurements.—Measurements are summarized in Table 24. Remarks.—Only three encrusting specimens were found within the Hermitage Formation. Though not within the realm of the present study area, preliminary examination of the overlying Cannon Formation re- veals this species to be fairly common as both a ra- Table 24.—Quantitative data, Monticulipora sp. A. See Key to Abbreviations, p. 33, for explanation. Character Range Mean ZCD INJESIN! eeeecasce -18—.20 18 HOMO yen .18-.23 19 IROSYNY, Soomacae .18-.23 19 ZCD (mac) NII? 2.55.5 .25—.30 28 HEM areas .26-.34 30 MOAT eee .25—.34 29 ZWT NIE IWit. cass .01—.03 .02 13 Ue aca secee .02—.03 02 TOMAS ya ssicceis -01—.03 .02 AD (lam) NIMIV) ecweetee .03—.04 04 HEM) asics she .03—.04 03 ANON Sochoaue .03—.04 .04 Mode S.D. No. Meas. No. Spec. 18 .008 10 2 18 .022 5 1 18 O14 15 3 30 .025 5 2 30 033 4 1 30 028 9 3 .02 O05 10 2 .02 .004 5 1 02 00S 15 3 04 00S 10 2 03 .006 5 1 04 00S 15 3 MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH Sy/ mose as well as encrusting form. In this latter forma- tion, the lowermost exozone/outer endozone of the ra- mose forms have no cystiphragms but rather, flat dia- phragms which are spaced about one zooecial cavity diameter apart. Spacing increases within the inner en- dozone. Zooecia curve evenly and gradually to inter- sect the colony surface at a slightly oblique angle. Within the endozone, parallel-sided walls are some- times fairly crenulate or beaded and acanthostyles are absent. Specimens assigned to Monticulipora sp. A are not formally named since the available material is not suf- ficient to determine specificity. Several characters ap- pear to be consistent with Boardman and Utgaard’s (1966, p. 1093) definition of Monticulipora, namely, a poorly defined laminar wall structure (i.e., ““markedly granular’ of many authors), short acanthostyles lim- ited to thick-walled zones, and cystiphragms and pla- nar diaphragms throughout the length of zooecia (this species has only diaphragms in the endozone of ra- mose forms, not inconsistent with Boardman and Ut- gaard’s generic concept). The present species also pos- sesses rather polygonal zooecial cavity outlines, not mentioned by Boardman and Utgaard, but character- istic of so many species of Monticulipora. Distribution.—Localities NL IV, HCM. Studied material.—Hypotypes NL IV 72(107)B-4L- A(M) [USNM 432173], NL IV 85(120)A-3RB-A(M) [USNM 432174], HCM 43(82)B-5-N(M) [USNM 432175]. Family BATOSTOMELLIDAE Miller, 1889 Genus BYTHOPORA Miller and Dyer, 1878 Type species.—Helopora dendrina James, 1878 (= Bythopora fruiticosa Miller and Dyer). Bythopora dendrina (James, 1878) Plate 10, Figures 4—6 Helopora dendrina James, 1878a, p. 3; 1878b, p. 14—15. Bythopora fruiticosa Miller and Dyer, 1878, p. 6, pl. 4, figs. 6, 6a. Bythopora dendrina (James). Nickles and Bassler, 1900, p. 185; Bas- sler, 1906, p. 20; Ross, 1967b, p. 642-644, pl. 67, figs. 1-8, 10— 13, pl. 69, fig. 4, pl. 72, fig. 3; Singh, 1979, p. 203-206, pl. 22, figs. 3-5, pl. 23, figs. la—Ic, 2. Description.—Zoaria ramose. Slender, cylindrical branches. New zooecia initiated predominantly in out- er endozone. Zooecial cavity outline is elliptical (due to low surface angle) in tangential section. Actual cav- ity outline as viewed perpendicular to zooecial axis is rounded. Endozonal zooecial cavity outlines polygonal and in transverse section, sometimes exhibit a pseu- doradial arrangement. Endozone narrow. Zooecia curve evenly to intersect zoarial surface at low angle, commonly between 30° and 45°. Slight zooecial bend sometimes occurs in lower exozone. Endozonal walls even to wavy and fairly parallel sided. Rarely a rela- tively large zooecium in middle of endozone. Wall thickness increases continuously from endozonal/exo- zonal transition to the colony surface where it some- times tapers slightly. Exozone narrow. Wall micro- structure generally composed of U- to V-shaped lam- inae that sometimes appear to possess a median dark line. Diaphragms absent to extremely rare in exozone. If present, thin, even, perpendicular to zooecial wall. Absent in endozone. No mesozooecia. Minute acan- thostyles between zooecia and at zooecial corners. Identified by clear calcitic rods. Surrounding laminae thin to indistinct. Obscure in longitudinal section. Styles number mainly three to five around each zooe- cium. Measurements.—Measurements are summarized in Table 25. Remarks.—Bythopora dendrina typically has low surface angle, no to very rare diaphragms, three to five minute acanthostyles surrounding each zooecium, an endozonal width varying from 0.5 to 1.0 mm, and col- ony branch diameters up to 1.5 mm across. In many respects Bythopora dendrina is extremely similar to Batostomella subgracilis described herein (p. 61). The two species together form a fairly contin- uous gradation in morphology, yet the endpoints are so totally different that the validity of placing them within one species grouping would be very suspect. Ross (1967b) also noted a similarity between her Champlainian B. dendrina and specimens of Bytho- pora subgracilis from Estonia as described by Bassler (1911) (Batostomella subgracilis of this report). The only difference she noted was that the Estonian ma- terial had a greater number of zooecia per 2.0 mm than for B. dendrina (eight as compared to four to five). Measurements of this type do not reflect size of zooe- cial tube since measurements must be normalized for wall thickness and surface angle. Measurements of zooecial diameters of Bythopora subgracilis figured by Bassler (1911, p. 241) show no significant difference between the two species. Additionally, measurements of zooecia per 2.0 mm made on specimens of Bytho- pora dendrina illustrated by Ross (1967b) do not show four to five but seven to eight. Not mentioned by Ross is the clear difference in colony branch diameter be- tween the two species. Her specimens of B. dendrina from New York State have diameters varying from 0.85 to 1.00 mm, while Bassler’s B. subgracilis varies between 2.0 and 4.0 mm. Besides the obvious difference in colony size, slight differences that exist between the two species are the common occurrence of slightly larger zooecia within the innermost endozone in specimens of Batostomella 58 BULLETIN 353 Table 25.—Quantitative data, Bythopora dendrina (James). See Key to Abbreviations, p. 33, for explanation. Character Range Mean Mode SyDE No. Meas. No. Spec. MxZCD NL IV 30-49 (65-84) ......... .09—.26 17 18 036 60 6 NL IV 66-72 (101-107) ....... -12—21 16 18 .024 20 2 NL IV 85-116 (120-151) ..... -11—.30 .20 20 .040 125 13 NIG AINY IKONYN Ly oooksdandaagaconc .09—.29 18 18 .040 205 21 EBr4aS 85 eirsctensasasisccsesicsanes .12—.22 BilZ/ 16 024 47 6 GBH22-149) oeeccssececeriiecs 11-21 ails) BA, SK all) 028 21 3 (els iid KOM WN Eitessonaasneuuascoseaen 11-.22 16 BSI) .026 68 9 IGM G aeneceasceneacees ecco: .O8—.23 17 .18, .20 040 43 5 N05 Sian eee Conn maoerosppaanancnad .17-.27 .20 19 028 9 1 NASIR MLONIYAN Es nc apcantoqacadtuce O08—.27 18 20 040 52 6 IKON WN Up Gace snooddeneesecapansoctne 08—.30 18 18 038 325 36 MnZCD NL IV 30-49 (65-84) ......... .06—.12 08 .08 O12 60 6 NL IV 66-72 (101-107) ....... .O5—.10 08 08, .09 O12 20 2 NL IV 85-116 (120-151) ..... -O5—.12 08 .08 O15 125 13 INDE @M AWE of aeteerctceecettiecria: .OS5—.12 08 08 014 205 21 (G13) Coie) Sapo dassoobasaconecsager .06—.10 08 07 008 47 6 G13} SS) i onccdauasbacacoonene .O5—.10 08 08 O13 21 3 EBMOMAS een cese eee eee .OS5—.10 .08 07 .009 68 9 FIG Migs saosecteoc cre oaececeeeee .04—.10 08 08 O15 43 5 WWI Sete sicteicinaioe ttisree nite teiscietee .07—.10 08 08 .009 9 1 WES MO MANY msec. ceecieenectt .04—.10 08 08 .014 52 6 DROWAWE. teatsscsemeitsseteacteccits 04—.12 08 08 014 325 36 ZCD (endo/long) NL IV 30-49 (65-84) ......... .08—.14 10 10 O14 29 5) NL IV 66-72 (101-107) ....... — —_ —_— — — — NL IV 85-116@20=151)) 32:.- 08-15 11 10 .012 49 8 INEALV MODAL areeaceceenas asc 08-15 =i 10 .013 78 13 CEBrAS=85 Ferd casas cise aiicciteracte .O7—.18 alliit 10; 12 .024 31 6 CBe22= 1A OU Srna ccieisiatecierts -10—.16 12 10 024 12 2 (GJM NONVNY Boeaaocacosbocosedeooo .O7—.18 12 10 .024 43 8 1G (OMY Ie sod amneppeeabruscoucssedsDas .10—.24 14 sil .036 14 2 WEB Bi crostconassiisejecie sc cmeseticiestar —_ —_ — — — — WEST TOMA ete esce leis clsleres .10—.24 14 2 036 14 2 KO} VN Diy seen easoceeeasnaoosnecsccs .O7—.24 11 023 135 23 ZWT NL IV 30—49 (65-84) ......... .02—.10 06 OS 018 60 6 NL IV 66-72 (101-107) ....... .O2—.12 07 06, .10 029 18 2 NL IV 85-116 (120-151) ..... .O1—.07 04 04 014 123 13 IN| E14 KOMWN Dt ceeeacasodesecone .O1—.12 05 04 .022 201 21 @Bya5=89 7 3...c ste nme ceieesteneas .03—.10 OS 04 019 42 6 GBT I22 Ag eae cccoeeeiemnseer es .03—.09 OS 04 .017 21 3 GSB MOTTA Hee sectascensieeite cert .03—.10 OS 04 .018 63 9 LG Miter ned fees ctise ns ace eee .02-.17 06 04 .028 42 5 IWIBI, ta siswieieisswris Seerine saeeiee lances .04—.06 05 04 O10 10 1 WES Te MOMAIE Tj lore cgetesiceicet 02—.17 06 04 026 52 6 POMAT etre ccteeisci ns jscsesisecrc .O1—17 05 04 .022 316 36 Z/mm? NL IV 30-49 (65-84) ......... 26-34 31 32 2.8 7 6 NL IV 66-72 (101-107) ....... 24-34 29 — dal 2 2 NL IV 85-116 (120-151) ..... 28-54 38 34 6.9 12 11 INTE TV TOTALLY eiasssenecseeeere 24-54 35 34 6.6 21 19 GBxA5=85) se cedeenee seceacseasee 48 48 —— 0.0 1 1 GBuI2 2 VAG ie oe am ssetne mle bisicaraecie: 34 34 —_— 0.0 1 1 CBULOMAL coc sceeseeaseceecce 34-84 41 — OM) 2 2 IGM tascam estpicteeceiieseeittsttcls 36 36 — 0.0 1 1 WIB! re ncncncceemaceracsmecneenne ces 36 36 — 0.0 1 1 WEST BOTA . scsccccesee sets 36 36 36 0.0 2 2 MOWAL Hs A20 eh ectlectideeceee sien 24-54 35) 34 6.6 25 23 MxMCD* NL IV 30-49 (65-84) ......... .04—.14 06 OS 025 18 6 NL IV 66-72 (101-107) ....... .O5—.14 09 .09 .029 7 2 NL IV 85-116 (120-151) ..... .03—.12 .O7 .08 .022 39 13 INL NASI WO MWN Ex Gopscacosacocnee ie .03—.14 .O7 10) 024 64 21 MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH 59 Table 25.—Continued. Character Range (@) 3). Be ay Bopecsooesdsonacdeaondod .03—.09 (OLY PASE ce onnasqocoponsedsson .04—.07 GBT OAT oss -teeriecsta chen esters .03—.09 IE LEIM LS sagpouaScospoaCUnesaadeoOConS .04—.10 WIS ar nets erclerai tales ctaseieretsiete atic ote .04—.12 \ABESIU IROWAN Las So ousononebooode .04—.12 OAM ei eracicicteemclerieleiseie ctorstereieisis1aere .03—.14 MnMCD* NL IV 30-49 (65-84) ......... .02—.04 NL IV 66-72 (101-107) ....... .02—.05 NL IV 85-116 (120-151) ..... .02—.06 INDE INA RON DAN by SS aneeeoe-Anedc .02—.06 (G1 3: Sty shesetiooaecoeen cunAnaoper -02—.05 (G)ey IP Pe tN Ee concedsooesononeee .02—.04 CBS OMA are ececas esses .02—.05 HIG MG eee erne te scet aooeeaeec ses .02—.05 IWIB geese secant costes tarect Sieestcae -02—.05 WEST TOMAD ceo rer.cceceeisen .02—.05 IILO}IN Cees goncseeneeposeOmparacros .02—.06 CD NL IV 30—49 (65-84) ......... 1.2-1.5 NL IV 66-72 (101-107) ....... 1.0 NL IV 85-116 (120-151) ..... 1.0-1.5 INE DV SO MAT rr cceetaessiecertter: 1.0-1.5 (Cis) 7 SSC By Googosoudesopoacsodaaonn 1.0-1.2 CBSI22=TAO TR oa. secrsteastressiee 1.0-1.4 (CIS IKONVAN ES cagsosaooncacoos000000 1.0-1.4 FAG Mbarara io ciated aciaioists otaratclatesstoysters 1.1-1.5 1.0-1.5 1.0-1.5 1.0-1.5 * = not true mesozooecia (see text). subgracilis as well as a different range in endozonal width (0.5 to 1.0 mm for Bythopora dendrina and 0.6 to 1.5 mm for Batostomella subgracilis). Based on these features alone, some overlap does occur, es- pecially where the large zooecia noted above are not obvious. An approach employed in the discernment of By- thopora dendrina as a separate and viable species is to note its preponderance in lithofacies with taxa other than Batostomella subgracilis, though at a few strati- graphic levels, both do co-occur (see stratigraphic range charts of individual species occurrences; see Text-figures 7-10). The presence of the latter species is commonly correlated with the presence of relatively low energy environment that includes Bythopora den- drina (see text on Trepostome Bryozoan Assemblages, p. 13). Also, Bythopora dendrina has been noted to occur elsewhere in assemblages not containing Batos- tomella (e.g., Ross, 1967b). With this in mind, for col- onies that fall into either of these two species group- ings, those with branch diameters of less than 1.5 mm and without large inner endozonal zooecia are as- signed to Bythopora dendrina. Specimens with branch Mean Mode S.D: No. Meas. No. Spec. .06 .03, .04, .020 11 4 .05, .06, .08 06 .06 013 7 2, 06 .06 O17 18 6 07 07 O17 9 4 .08 a .033 4 1 07 07 .022 13 5 .07 .06 .023 95 32 .03 02 .009 18 6 .04 .02, .04, .05 012 7 2 .03 04 .009 39 17 .03 04 .009 64 21 .03 02 .010 11 4 .03 02, .04 009 7 2, .03 02 .009 18 6 .03 .02, .04 012 9 4 .03 02 O13 4 1 .03 02 .012 13 5 .03 04 O10 95 32 1.4 1.2 106 5 5 1.0 1.0 .000 2 2 1-33 1.4 .170 1 13 1.3 1.0, 1.4 173) 20 20 1.1 1.0 120 6 6 1.2 — .202 3 3 eit 1.0 149 9 9 1.3 — 175 4 4 12 — 354 2 2 1.3 ES PAU 6 6 12 1.0 .178 35 35 diameters greater than 1.5 mm are assigned to Bato- stomella subgracilis. This latter species also commonly has specimens with relatively large zooecia in the inner endozone as well as frequent constrictions along zooe- cial tubes, a function in part of its wider exozone. Slight constrictions due to thickened exozonal walls are un- common in specimens assigned to Bythopora dendrina. Ross (1967b) notes the presence of one to two me- sozooecia per zooecial opening in tangential section of the holotype of B. dendrina. Singh (1979, p. 206) be- lieves that these are not true mesozooecia but represent “‘small openings ... common in cuts that are slightly deeper than usual and oblique. These are obtained when zooecia are cut at the zone of constriction. The appearance of the deeper tangential sections is mostly a reflection of the narrow exozone characteristic of this species.’’ Specimens from the present study area show mesozooecia-like openings in tangential section, but, as in the holotype material, do not show mesozooecia in longitudinal section. The observations of the present author concur with those of Singh’s. The presence of this species (or indeed, of species of Batostomella) in collections of early workers is un- 60 BULLETIN 353 known due to the lack of description and illustration of microscopic morphology (e.g., McFarlan, 1931), a point alluded to by Ross (1967b, p. 643-644). Distribution.—Localities NL IV, CB, HCM, WB. Studied material.—Hypotypes NL IV 30(65)A-1- B(M) [USNM 432176], NL IV 30(65)C-3L-D(M) [USNM 432177], NL IV 43(78)-B-6L-Y(M) [USNM 432178], NL IV 44(79)A-14LA-D(M) [USNM 432179], NL IV 49(84)A-6R-Y(M) [USNM 432180], NL IV 49(84)A-8RB-A(M) [USNM 432181], NL IV 66(101)A-10-A(M) [USNM 432182], NL IV 72(107)B-2L-J(M) [USNM 432183], NL IV 85(120)A-7L-D(M),E [USNM 432184], NL IV 85(120)A-2LB-A(M) [USNM 432185], NL IV 89(124)A-5B-C(M) [USNM 432186], NL IV 93(128)A-11-D(M) [USNM 432187], NL IV 93(128)A-3-A (M) [USNM 432188], NL IV 93(128)A-4-L(M) [USNM 432189], NL IV 93(128)A-4-A(M) [USNM 432190], NL IV 93(128)A-2-I(=J)(M) [USNM 432191], NL IV 93(128)A-13-E(M) [USNM 432192], NL IV 96(131)B-6-E (M) [USNM 432193], NL IV 100(135)A-2L-Y(M) [USNM 432194], NL IV 108(143)A-18-C(M),D,E [USNM 432195], NL IV 116(151)A-3-D(M) [USNM 432196], NL IV 19(54)B-5-A [USNM 432197], NL IV 30(65)A-3-C [USNM 432198], NL IV 30(65)A-1-C [USNM 432199], NL IV 30(65)C-5-X [USNM 432200], NL IV 37(72)B-2-H [USNM 432201], NL IV 37(72)B- 5-B [USNM 432202], NL IV 49(84)A-11L-P [USNM 432203], NL IV 49(84)A-6R-Z [USNM 432204], NL IV 51(86)A-10L-A [USNM 432205], NL IV 51(86)A-2L-A [USNM 432206], NL IV 61(96)A-4-I [USNM 432207], NL IV 61(96)A-4-D [USNM 432208], NL IV 61(96)A-7-G [USNM 432209], NL IV 61(96)A-9-B [USNM 432210], NL IV 61(96)A- 4-G [USNM 432211], NL IV 61(96)A-9-A [USNM 432212], NL IV 63(98)A-4LB-UU [USNM 432213], NL IV 63(98)A-2LB-S [USNM 432214], NL IV 63(98)A-SLA-G [USNM 432215], NL IV 66(101)A- 8-A [USNM 432216], NL IV 66(101)A-10-B [USNM 432217], NL IV 66(101)A-5A-B [USNM 432218], NL IV _ 72(107)B-L-L [USNM 432219], NL IV 72(107)A-4-D [USNM 432220], NL IV 85(120)A- 10L-C [USNM 432221], NL IV _ 85(120)A-7L-F [USNM 432222], NL IV 85(120)A-3RB-B [USNM 432223], NL IV 93(128)A-10-B [USNM 432224], NL IV 93(128)A-11-A [USNM 432225], NL IV 93(128)A-11-B [USNM 432226], NL IV 93(128)A- 11-C [USNM 432227], NL IV 93(128)A-4-A [USNM 432228], NL IV 93(128)A-10-A [USNM 432229], NL IV_ 93(128)A-4-C [USNM 432230], NL IV 93(128)A-1-P [USNM 432231], NL IV 96(131)B- 6-D [USNM 432232], NL IV_ 100(135)A-13L-J [USNM 432233], NL IV 100(135)A-10L-Q [USNM 432234], NL IV 100(135)A-6L-K [USNM 432235], NL IV 100(135)A-4L-G [USNM 432236], NL IV 100(135)A-2L-W [USNM 432237], NL Iv 108(143)A-13L-J [USNM 432238], NL IV 108(143)A-12-B [USNM 432239], NL IV 108(143)A-2-O [USNM 432240], CB 45A-4-A(M) [USNM 432241], CB 55A-9-C(M) [USNM 432242], CB 62A-5-B(M) [USNM 432243], CB 72C-7L-C(M) [USNM 432244], CB 72C-5L-D(M) [USNM 432245], CB 85A-7-C(M) [USNM 432246], CB 122A-9-A(M) [USNM 432247], CB 132C-7-A(M) [USNM 432248], CB 149A-6-B(M) [USNM 432249], CB 41A-4-A [USNM 432250], CB 54A-4-B [USNM 432251], CB 55B-2-E [USNM 432252], CB 85A-12L-C [USNM 432253], CB 132C-8-A [USNM 432254], CB 138B-4-A [USNM 432255], CB 161A- 1-E [USNM 432256], CB 45A-6-A(F) [USNM 432257], CB 45A-4-B(F) [USNM 432258], CB 45A- 3-A(F) [USNM 432259], CB 62A-9-A(F) [USNM 432260], CB 72C-6L-A(F) [USNM 432261], CB 72B-2-A(F) [USNM 432262], CB 72C-2LA-C(F) [USNM 432263], CB 72C-6L-B(F) [USNM 432264], CB 82A-3-C(F) [USNM 432265], CB 82A-2-D(F) [USNM 432266], CB 82A-2-C(F) [USNM 432267], CB 85A-5-A,C(F) [USNM 432268], CB 85A-12L- B(F) [USNM 432269], CB 114A-7-A(F) [USNM 432270], CB 114A-2-A(=3-A)(F) [USNM 432271], CB 114A-6-A(F) [USNM 432272], CB 120A-2-A(F) [USNM 432273], CB 120A-3-A(F) [USNM 432274], CB 122A-18-A(F) [USNM 432275], CB 122A-7- A(F) [USNM 432276], CB 122A-8-A(F) [USNM 432277], CB 122A-2L-A(F) [USNM 432278], CB 122A-15-A(F) [USNM 432279], CB 132B-2-A(F) [USNM 432280], CB 132C-5L-A(F) [USNM 432281], CB 132C-5L-C(F) [USNM 432282], CB 149A-2-B(F) [USNM 432283], CB 149A-2-C(F) [USNM 432284], CB 150B-4-B(F) [USNM 432285], CB 156A-3-B(F) [USNM 432286], CB 159A-2-B(F) [USNM 432287], CB 159B-2-B(F) [USNM 432288], CB 161A-5-A(F) [USNM 432289], HCM 11(50)A-5- R(M) [USNM 432290], HCM 38(77)B-1-A(M) [USNM 432291], HCM 43(82)C-2-I(M) [USNM 432292], HCM 50(89)A-B(M) [USNM 432293], HCM 50(89)A-J (M),K,L [USNM 432294], HCM 5(44)A-3-C [USNM 432295], HCM 38(77)A-3-O [USNM 432296], HCM 50(89)A-A [USNM 432297], HCM 11(50)A-6-H(F) [USNM 432298], HCM 11(50)B-1-L(F) [USNM 432299], HCM 38(77)A-3- P(F) [USNM 432300], WB 44(56)A-2-A(M) [USNM 432301], WB 32(44)A-4-A [USNM 432302], WB 38(50)A-2-A [USNM 432303], WB 4(16)A-5R-A(F) [USNM 432304], WB 19(31)A-2-A(F) [USNM MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH 61 432305], WB 20(32)B-7-A(F) [USNM 432306], WB 44(56)A-5-A(F) [USNM 432308]. Genus BATOSTOMELLA Ulrich, 1882 Type species.—Chaetetes gracilis Nicholson, 1874; by subsequent designation, Miller, 1889, p. 294. Batostomella subgracilis (Ulrich, 1893) Plate 11, Figures 1—4 Homotrypella (2) subgracilis Ulrich, 1893, p. 230, 231, pl. 26, figs. 10-16. Bythopora subgracilis (Ulrich). Bassler, 1911, p. 241, 242, text-figs. 135a-d, 136a, b. Description.—Zoaria ramose. Branches cylindrical and 1.5 to 3.5 mm in diameter (non-varietal form). New zooecia initiated predominantly in outer endo- zone. Zooecial cavity outlines elliptical to elongate in direction of zoarial axis. Actual cavity outlines round- ed when observed perpendicular to zooecial axis. En- dozonal zooecial cavity outlines polygonal and in transverse section, sometimes exhibit a pseudoradial arrangement. Zooecia curve evenly from endozone and intersect colony surface at generally 45° but some- times up to 90°. Zooecial bend occasionally occurs in lower exozone. Endozonal walls thin, fairly even and parallel-sided. One to several megazooecia in inner- most endozone (= axial zooecia). Wall thickness in- creases continuously in a zooecially distal direction from endozonal/exozonal transition into lower to mid- exozone, commonly slightly decreasing the diameter of the zooecial cavity, after which wall thickness re- mains fairly constant with minor periodic thickening or thinning before intersecting the colony surface. Walls composed of U-shaped laminae, the apices of which are connected by a faint dark line. Diaphragms absent to rare in exozone. When present are thin, even and perpendicular to exozone walls. Absent in endo- zone. No mesozooecia (though thickening of outer wall in places gives the appearance of mesozooecia in tangential section). Minute acanthostyles between zooecia and at zooecial corners. Number about three to five around each zooecium. Obscure in longitudinal section. More obvious in deep tangential cuts. Measurements.—Measurements are summarized in Table 26. Remarks.—For many years the concept of Batos- tomella as a genus was clouded. Part of the confusion was a result of Nickles and Bassler (1900) assigning Chaetetes gracilis to Bythopora Miller and Dyer (1878). Since Chaetetes gracilis was considered by Miller (1889) to be the type species of Batostomella, this genus would then be a junior synonym of Bytho- pora. Further confusion resulted when the type mate- rial of C. gracilis was lost. The inability to locate this material prompted Ross (1967b, p. 641) to write “the generic concept of Batostomella remains unknown and the name belongs to the list of unrecognizable generic names of ectoprocts.”’ Singh (1979, p. 200), prompted in part by Ross’s (1967b) rediscovery of the original type material of Bythopora (Helopora dendrina James), reestablished the concept of Batostomella. He noted that robust, externally smooth zoaria which have thick exozones and thickened zooecial walls, all char- acteristic of Chaetetes gracilis are distinctive and do not fit the concept of Bythopora ‘“‘which is character- ized by delicate, slender forms with an extremely thin exozone.”” Singh (1979, p. 200) added that ‘‘in spite of the fact that the types of C. gracilis are unavailable for study ... No useful purpose would be served by placing Batostomella in a list of unrecognized genera, as this would necessitate erection of a new genus and species.’ Singh (1979, p. 196) mentioned that “*...Batostomella includes robust forms that have zooecial openings constricted in the exozone by thick- ening of zooecial walls, while Bythopora has only slightly flared openings.”’ Further, he writes (p. 202) ““Bythopora differs from Batostomella in that the me- gazooecia are not developed in the endozone.” Singh’s concept of the genus is followed here. Ulrich (1893, p. 231) noted that his specimens of Homotrypella (?) subgracilis from the Middle Ordo- vician of Minnesota resemble Chaetetes gracilis (the type species of Batostomella) more than any other spe- cies. The species described herein differs from B. gracilis of Singh (1979) by lacking mesozooecia and by having less distinctive acanthostyles and a relative- ly narrow endozone. The reader is referred to the Re- marks section under B. dendrina for further comments concerning its differentiation from B. subgracilis. As in B. dendrina, tangential sections of B. subgra- cilis show mesozooecia-like openings. Distinct meso- zooecia are difficult to ascertain in longitudinal sec- tion. There are many instances of wall thickening within zooecial tubes producing smaller diameters than common. These thickenings are most likely responsi- ble for the mesozooecia-like openings observed in tan- gential section. Distribution—Localities NL IV, CB, HCM, WB. Studied material.—Hypotypes NL IV 93(128)A-2- F(M) [USNM 432309], NL IV 93(128)A-11-J(M) [USNM 432310], NL IV 93(128)A-2-L (M) [USNM 432311], NL IV 93(128)A-2-M(M) [USNM 432312], NL IV 93(128)A-3-K(M) [USNM 432313], NL IV 93(128)A-4-I(M) [USNM 432314], NL IV 93(128)A- 4-H(M) [USNM 432315], NL IV 93(128)A-6-B (M) [USNM 432316], NL IV 93(128)A-2-H(M) [USNM 432317], NL IV 94(129)A-3L-I(M) [USNM 432318], NL IV 96(131)C-1-C(M) [USNM 432319], NL IV 62 BULLETIN 353 Table 26.—Quantitative data, Batostomella subgracilis (Ulrich). See Key to Abbreviations, p. 33, for explanation. Character Range Mean Mode S.D. No. Meas. No. Spec. MxZCD } 1 Oe IY eoadenasesecoere .09—.27 alls) a2. 035 195 20 (G1) S51 Sy aapnesouaeaas -10—.22 16 14, .18 .032 61 7 CBRIS De ecurerccceercs .12—.20 16 14 025 13 2 CBeTORAT ees eee .10-.22 16 14 030 74 9 JELGIM C ocenacananooscaaser -10—.19 14 13 .027 20 2 \i.15 Sn redeaneconacaassee .10—.24 16 all/ .034 40 4 WEST TOTAL =... .. .10—.24 16 13 .032 60 6 WOMANS acres tias-cictetastt .04—.27 alls) 12 .034 329 35 MnZCD INTERV pacer arctscee acca: .05—.13 07 07 013 195 20 (3) SSS)" sepnonaccedos .05—.12 08 07 O13 61 7 G13} NE. Geseacasatiocoxen .06—.08 07 08 .007 13 2; EBMODAL s-ecesir .05—.12 .08 07 012 74 9 IGM nee ssacreassecnece .06—.14 09 07-61 .020 20 2 \i2) Ss Socbanadspocesasacen .05—.10 08 07 O11 40 4 WEST TOTAL se... .05—.14 08 07 016 60 6 NOW ON bapeascasctoodason .O5—.14 08 .O7 O14 329 35 ZCD (endo/long) INTEL 6 ecrissctrteniseeeiecs .09—.18 al2 10 020 90 14 CBYSS=89 Fe secineetacee: .10—.18 13 10 .030 23 4 (Gis) MEP) nasoscoooncsasne .08—.26 2 12 048 ilg/ 2 (2) INONVANG, casososcad .08—.26 13 10 .038 40 6 Is(GWl Gon qpondooonaccnaon .12-.19 15 — .036 3 1 \'.i/l S eabodaaasarcbosascasce .10-.20 14 16 .026 17 4 WEST TOTAL, jc... .10—.20 14 i125 LG .027 20 5 TOTAL fa jachins(ecisccie .08—.26 a2 10 028 150 25 ZWT INE Wa enasesedaacdaanac .03—.13 06 .06, .07 -017 193 20 GCBESS=S85 irre acess .04—.13 06 07 019 63 7 (Sieh als Pee saddsosuondsede .06—.10 08 .07, .08 .012 16 2 (Qs, INOMVNE, sancoeoneas .04—.13 .O7 07 O19 79 9 FIG Magee eesctacceecterts .O5—.12 08 .06, .07 .022 20 2 WBE cistcisigersistetrsietelsiesieies .O1—.12 07 05, .09 .027 40 4 WEST TORAT esac .01—.12 07 06 .025 60 6 TOTAL asc assert .O1—.13 07 07 019 332 35 Z/mm? IND ELIDNYG # SAndoonpaasoenos 25-40 33 34 4.3 20 19 EBHSS=89 pe. cls ceereeciar 28-39 30 28 4.3 6 4 (Giz) WE Pes sdcnoosocpowaas 30 30 —_— 0.0 1 1 (G13) ANODE), Saenodocone 28-39 30 28, 30 339) 7 5 IGM eee aceceemecaes 30-38 34 — Sei/ 2 1 WB) sa gaccne Sonaeeseigaee 16-36 27 — 7.9 6 4 WEST RODAL a... 16-38 29 30 7.8 8 5 AWOYAN eer aeannndonndeaae 16-40 32 30 5.4 35 29 MxMCD* INE SIV fertioseireniscars .02—.13 .06 05 O19 115 20 EBIS5=85) see seeeseicte .03—.16 07 06 .026 30 7 (CU Ey) ponesepannebns -04—.07 06 05, .07 .012 8 2 (QS MNONYNED cecoosdeous -03—.16 07 .06, .07 .024 38 9 HEM aa. eesceceee ta .05—.09 07 -06, .07 O13 10 2 WIBitaanscesaecaciscmseriest .03—.10 07 06 O17 20 4 WEST TOTAL, .:...... .03—.10 07 .06 .016 30 6 MOIRA Wace jceonte sect .02—.16 06 05 .020 183 35 MnMCD* INDE EW Giger erate ee .02—.06 .03 03 .010 1S 20 (CBYSS=89 5 eel sesteeeerlele .02—.05 .03 04 010 30 7 CBMIS2 saee. te eerasce .02—.06 03 .03 014 8 2 CBiTOTAD ware -02—.06 03 04 O10 38 9 13 (Gl Bap anapooocopacsnade .04—.07 OS 05 .008 10 2 WB) aiFiSesde canis etear .02—.06 04 03 O11 20 4 WEST TORAL, --...3- .02—.07 04 .04 .012 30 6 Ww n IKONON UD, Srasosepanecosse .02—.07 03 03 O11 183 MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH 63 Table 26.—Continued. Character Range Mean Mode S.D. No. Meas. No. Spec. CD INILEINY osjoqsogsedoceods 1.8-3.5 2.6 ZON2'5 53:0 496 20 20 G@Bi55=85) ose cse ccc 1.5-3.5 2.0 1.8, 2.0 675 7 W C13}. SY) Soseqcapoaeosoa 2.0 2.0 — 000 2 2) CRENOTA TU racirenccinaist 1.5-3.5 2.0 2.0 585 9 9 lALEWil Saas obageagnen9090 1.8-2.2 2.0 — 354 2 2 \VASP dare dappabmeaseiqengan 1.8-3.0 2.4 3.0 658 4 4 \WARS IP IMOVIE Gosagoe 1.8-3.0 2.3 1.8, 3.0 79) 6 6 TROON LS dqnenssanenannse 1.5-3.5 2.4 2.0 579 35 35 * = not true mesozooecia (see text). 96(131)C-5-G(M) [USNM 432320], NL IV 100(135)A-2L-A(M) [USNM 432321], NL IV 100(135)A-12L-H(M) [USNM 432322], NL IV 100(135)A-4L-Z(M) [USNM 432323], NL IV 100(135)A-9L-NN(M) [USNM 432324], NL IV 100(135)A-10L-QQ(M) [USNM 432325], NL IV 100(135)A-5L-G(M) [USNM 432326], NL IV 116(151)A-5-D(M) [USNM 432327], NL IV 116(151)A-2-A(M) [USNM 432328], NL IV 93(128)A-3-F [USNM 432330], NL IV 93(128)A-4-E [USNM 432331], NL IV 93(128)A-2-G [USNM 432332], NL IV 93(128)A-4-EG [USNM 432333], NL IV 93(128)A-6-C [USNM 432334], NL IV 93(128)A- 9-C [USNM 432335], NL IV 93(128)A-2-E [USNM 432336], NL IV 93(128)A-11-K [USNM 432337], NL IV 93(128)A-1-D [USNM 432338], NL IV 93(128)A- 12-F [USNM 432339], NL IV 93(128)A-1-E [USNM 432340], NL IV 93(128)A-3-E [USNM 432341], NL IV 93(128)A-9-J,K [USNM 432342], NL IV 93(128)A-6-D [USNM 432343], NL IV 93(128)A-3-C [USNM 432344], NL IV 93(128)A-3-D [USNM 432345], NL IV 96(131)C-5-A [USNM 432346], NL IV 93(128)B-2-A [USNM 432347], NL IV 96(131)B- 5-A [USNM 432348], NL IV 96(131)B-4-E [USNM 432349], NL IV 96(131)D-2-D [USNM 432350], NL IV 96(131)C-5-E,D [USNM 432351], NL IV 96(131)C-2-D [USNM 432352], NL IV 96(131)D-4-C [USNM 432353], NL IV 96(131)C-4-A [USNM 432354], NL IV 96(131)B-7-E [USNM 432355], NL IV 100(135)A-2L-C [USNM 432356], NL IV 100(135)A-4L-W [USNM 432357], NL IV 100(135)A- 9L-D [USNM 432358], NL IV 100(135)A-9L-DD [USNM 432359], NL IV 100(135)A-5L-J [USNM 432360], NL IV 100(135)A-2L-A [USNM 432361], NL IV 100(135)A-13L-D [USNM 432362], NL IV 100(135)A-5L-N [USNM 432363], NL IV 100(135)A- 6L-F [USNM 432364], NL IV 100(135)A-2L-T [USNM 432365], NL IV 100(135)A-2L-B [USNM 432366], NL IV 100(135)A-3L-KG [USNM 432367], NL IV 108(143)A-2-J [USNM 432369], NL IV 108(143)A-17-I,J [USNM 432370], NL IV 108(143)A-5-L [USNM 432371], NL IV 108(143)A- 13-G [USNM 432372], NL IV 108(143)A-14-G [USNM 432373], NL IV 108(143)A-14-D [USNM 432374], NL IV 108(143)A-13-D [USNM 432375], NL IV_ 108(143)A-17-F [USNM 432376], NL IV 116(151)A-1-A [USNM 432377], CB 55A-7-A(M) [USNM 432378], CB 55B-2-D(M) [USNM 432379], CB 67B-7-G(M) [USNM 432380], CB 72C-2LA- C(M) [USNM 432381], CB 85A-9-C(M) [USNM 432382], CB 85A-8-A(M) [USNM 432383], CB 85A- 5-B(M) [USNM 432384], CB 132C-5L-B(M) [USNM 432385], CB 132C-2-A(M) [USNM 432386], CB 79B-5-A [USNM 432387], HCM 38(77)B-2A-B(M) [USNM 432388], HCM 43(82)A-3-B(M) [USNM 432389], HCM_ 18(57)C-6-A(F) [USNM 432390], HCM 43(82)B-4-J(F) [USNM 432391], WB 44(56)B- 5-B(M) [USNM 432392], WB 44(56)B-2-D(M) [USNM 432393], WB 44(56)A-5-D(M),E(M) [USNM 432394]. Batostomella subgracilis (Ulrich) var. robusta new variety Plate 11, Figure 5 Plate 12, Figures 1—2 Description.—Specimens of this variety are similar in morphology to B. subgracilis but for distinctively larger colony branch diameters of about 3.5 to 6.0 mm. Measurements.—Measurements are summarized in Table 27. Remarks.—This variety is found only within the 96-108 foot (29.3—32.9 meter) interval at the Norris Lake IV section along with the typical form of B. sub- gracilis (see appropriate sections herein on the strati- graphic distribution of species occurrences) and is most likely an ecological variant. It is the opinion of the present author that it is important to point out such variance lest it lie buried within a static species de- scription. It is only by recognizing the distribution of species variance within a geographical and ecological framework that we can eventually begin to unravel evolutionary histories, even if we do not have an im- mediate explanation for the adaptational differences. Distribution.—Locality NL IV. 64 BULLETIN 353 Table 27.—Quantitative data, Batostomella subgracilis (Ulrich) var. robusta n. var. See Key to Abbreviations, p. 33, for explanation. Character Range Mean Mode S.D. No. Meas. No. Spec. MxZCD INIEMIV Ss eeisteteteets -O8—.20 14 ON2, .030 100 10 AEH oll@) INONVANE, seeaaad .08—.20 14 OR2 .030 100 10 15, .16 MnZCD INTERV vsti isscte .O5—.18 08 08 016 100 10 MOWAT ners .O5—.18 08 .08 016 100 10 ZCD (endo/long) INDENDW ars stelose .O8—.30 14 10 O57 40 6 MORAL yee. 08—.30 14 10 O57 40 6 ZWT INTE IO “Seacedee .04—.11 .07 07 O17 100 10 MOWAT Ys c:1-1- 04—.11 07 07 O17 100 10 Z/mm? NEAL ecccsee 24-38 33 34, 37 47 11 10 MOTAL 2 -cr 4: 24-38 33 34, 37 4.7 11 10 MxMCD* INILAINY seanesde .02—.11 06 05, .06 020 59 10 ANON EAN Ly oBaaane .02—.11 .06 05, .06 020 59 10 MnMcCD* INTESIV eeeisae .02-.05 .03 03 010 59 10 ROTA re: .02—.05 03 03 010 59 10 CD IN| Pal Wee ep oeceee 3.0-6.0 4.8 4.0, 4.5 .978 10 10 3:5510:0) MOTAW 3.0-6.0 4.8 4.0, 4.5 978 10 10 5.5, 6.0 * = not true mesozooecia (see text). Studied material.—Hypotypes NL IV 108(143)A- 1-B(M) [USNM 432395], NL IV_ 100(135)A-3L- E(M) [USNM 432396], NL IV 108(143)A-6-A(M) [USNM 432397], NL IV 108(143)A-14-I(M) [USNM 432398], NL IV_ 108(143)A-1-G(M) [USNM 432399], NL IV_ 108(143)A-15-D(M) [USNM 432400], NL IV_ 108(143)A-1-D(M) [USNM 432401], NL IV_ 108(143)A-3-C(M) [USNM 432402], NL IV 108(143)A-2-F(M) [USNM 432403], NL IV 108(143)A-14-J(M) [USNM 432404], NL IV 108(143)A-6-O [USNM 432405], NL IV 108(143)A- 18-B [USNM 432406]. Genus ERIDOTRYPA Ulrich, 1893 Type species.—Eridotrypa mutabilis Ulrich, 1893, p. 265, 266, pl. 26, figs. 20-32. Eridotrypa mutabilis Ulrich, 1893 Plate 12, Figures 3—4 Eridotrypa mutabilis Ulrich, 1893, p. 265, 266, pl. 26, figs. 20-32; Ross, 1967b, p. 637, 638, pl. 69, figs. 1, 5, 6, 9, 11, pl. 71, figs. 1-10; Karklins, 1984, p. 162-166, pl. 24, figs. 1-3, pl. 25, figs. 1-6. Eridotrypa aedilis Bassler, 1911, p. 242-244; McFarlan, 1931, p. 103, pl. 2, figs. 13, 15, pl. 8, fig. 13; Brown, 1965, p. 997, 998, pl. 117, figs. 3-6. Description.—Zoaria ramose. Zooecial cavity out- lines mainly subrounded and oval in tangential section with long axis of ovoid ellipse being parallel to zoarial branch axis. Oval outlines most common owing to ten- dency of zooecial outlines to intersect colony surface at oblique angle. Where more direct, zooecial cavity outlines subrounded to subpolygonal. Endozone zooe- cial cavity outlines polygonal in cross-section. Zooecia of inner endozone parallel the zoarial branch axis and begin to curve broadly in the outermost endozone. A slight zooecial bend sometimes occurs in lower exo- zone or at endozonal/exozonal transition. After bend, zooecia either continue to curve slightly, or proceed straight to colony surface. Surface angles generally shallow (approximately 45°), however, some are steep- er where zooecial bend is greater than average. Exo- zonal walls relatively thick and composed of broad U- to V-shaped laminae which occasionally appear to be divided by a median dark boundary line. This is more so in lowermost exozone where walls relatively thin and laminae V-shaped. Commonly walls increase very gradually in thickness in outer endozone. Wall thick- ness then increases rapidly but evenly in lower exo- zone, quickly attaining a thick wall that remains con- sistent in width or gradually increases through remain- der of exozone. Endozonal walls fairly parallel and even, though sometimes locally wavy. Endozonal au- tozooecial cavities generally larger than for exozone. Innermost (=axial) endozonal zooecia largest. For zooecia that bud in outer endozone, widest diameter found where zooecia curve in lower exozone. Cavity width then decreases as walls thicken peripherally. Di- aphragms thin, even, perpendicular to zooecial axis. Uncommon and widely spaced in inner endozone, in- MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH 65 Table 28.—Quantitative data, Eridotrypa mutabilis Ulrich. See Key to Abbreviations, p. 33, for explanation. Character Range Mean Mode S.D. No. Meas. No. Spec. MxZCD IND VaR ios costes: .14—.24 18 18 .024 30 6 CBR recess .14—.22 18 16 .023 15 3 TOTAL feass-- .14—.24 18 18 023 45 9 MnZCD NID Viees csc .07—.14 10 08, .10 018 30 6 CBR eee .O8—.12 10 10 014 15 3 MOWTAL.S Ssc-e .07—.14 10 10 016 45 9 ZWT INESEV ae see .06—.14 10 10 021 30 6 GBrisssiectrissce .10—.14 12 14 .O1S 15 3 ROMA sc .06—.14 itil .10 021 45 9 Z/mm? INIESIV gee 16-21 19 20 2.0 6 6 GB rereesceise: 15-19 17 “= 2.1 3 3 MOWPAL 2559: 5: 15-21 18 16, 20 2.1 9 9 MxMCD NESDV ges eee-5- .04—.14 08 08 021 27 6 CB sissogeenese .06—.09 07 08 O11 9 3 SOWA, = ace: .04—.14 .08 08 019 36 9 MnMCD INI CIN, aeacebace .04—.08 06 06 .012 27 6 CB ie eee A .04—.06 05 .04 009 9 3 ROMA. acne .04—.08 05 06 012 36 9 crease in frequency in outer endozone (where walls begin to thicken slightly). Here spacing is about one and one-half to two zooecial cavity diameters apart. Exozonal diaphragms spaced at intervals of about one zooecial cavity diameter apart. Sometimes more close- ly spaced and overlapping. Mesozooecia originate in lower exozone. Variable in abundance, rarely common. Cavity outlines subrounded to ovate as autozooecia. Diaphragms thicker than for autozooecia and spaced at approximately one-half to one mesozooecial cavity diameter apart. Some develop into autozooecia. Acan- thostyles minute and located mainly at zooecial cor- ners of exozone. Styles surrounded by laminae which are more prevalent in astogenetically old colonies. Maculae present. Composed of somewhat larger zooe- cia (megazooecia) with thicker walls. Measurements.—Measurements are summarized in Table 28. Remarks.—E. mutabilis of the study area is char- acterized by zooecia with generally low surface angles, commonly elliptical exozonal zooecial cavity outlines, axial megazooecia (see Key, 1990, for a discussion of the evolutionary importance of axial zooecia in Eri- dotrypa) which narrow in the outermost endozone-in- nermost exozone, flat diaphragms which are perpen- dicular to zooecial axes and found mainly in the exo- zone, rarely in endozone, mesozooecia that are gen- erally uncommon, minute acanthostyles present at zooecial corners, and relatively wide and laminar ex- ozonal walls that thicken rapidly within the lower exo- zone. Bassler (1911) and subsequently Brown (1965) con- sidered E. mutabilis to be junior subjective synonym of Cladopora aedilis Eichwald. Bassler (1911) pre- sented copies of Eichwald’s figures of Cladopora ae- dilis, external views of two zoaria. Also figured in Bassler (1911) is Dybowski’s (1877) diagrammatic representation of the internal morphology of C. aedilis. Bassler (1911) did not figure any specimens from the Baltic Provinces that he considered to be members of Eridotrypa aedilis and derived his species concept from Ulrich’s original description of E. mutabilis, commenting that Dybowski’s figures in conjunction with Eichwald’s was sufficient for identification of Baltic specimens. Ross (1967b) has examined Ulrich’s (1893) type material and has amplified the original species description and designated a lectotype. In ad- dition, she noted that as E. mutabilis is the type species of a valid genus, a more comprehensive study of Eich- wald’s material needed to be done before E. mutabilis can be placed in synonymy. Karklins (1984), in an effort to clarify the situation, felt that the figured spec- imens of Dybowski (1877) (also figured in Bassler, 1911) as well as hypotypes collected by Bassler from the Baltic and which were not figured in his 1911 work, illustrate the best possible concept of E. aedilis (especially since the primary types of this species have not yet been described). Differences found by Karklins (1984) to exist between E. mutabilis and E. aedilis included, for the latter species, a more longitudinal ar- rangement of exozonal zooecia in the general direction of branch growth, subelliptical (vs. generally subpo- lygonal) autozooecial cross-sections, basal diaphragms throughout the zoaria (vs. generally sparse in endo- 66 BULLETIN 353 zones and late exozones), and possibly thinner auto- zooecial wall laminae. Of these criteria documented by Karklins (1984), the distribution of basal diaphragms would appear, by far, to be the most clear-cut, consis- tent, and therefore, critical, discriminating factor be- tween E. aedilis and E. mutabilis of the present study area. Karklins (1984) noted the presence of Eridotrypa trentonensis from the Middle Ordovician of Kentucky and mentioned its close relationship to E. mutabilis. The two species are morphologically very similar, ex- cept that the former was stated by him to have smaller zoarial branch diameters, narrower endozones and ex- ozones, surficial angles at nearly 90°, and mostly sub- elliptical zooecial cavity outlines. Measurements from the present study area in Tennessee, as well as those by Ross (1970) from the Champlainian of New York State, and by Ulrich (1893) for type material of the species from Minnesota, reveal branch diameters for E. mutabilis to range primarily between 1.5 and 4.5 mm. Endozonal widths from the specimens described in this report commonly vary between 1.0 and 2.0 mm while exozonal widths usually range from 0.4 to 0.9 mm. From figured specimens of Ross (1967b, pl. 69, figs. 1,5, 11, pl. 71, figs. 3, 4, 7, 8) and Ulrich (1893, pl. 26, figs. 28, 31) endozonal diameters vary between 0.9 and 1.5 mm and exozonal measurements range from 0.4 to 0.8 mm. Variation of E. mutabilis var. mi- nor figured in Ulrich (1893, pl. 26, figs. 20, 29) falls within these ranges. Zooecial cavity outlines for the above material are generally elliptical to subrounded, and zooecia are most commonly inclined to the colony surface. While Karklins’ (1984) criteria serve to dis- tinguish his E. mutabilis from E. trentonensis within Kentucky, they are inconsistent with the above mea- surements which would appear to more closely overlap the zoarial, endozonal and exozonal widths of E. tren- tonensis (see Karklins, 1984, table 45) as well as the zooecial cavity outline shapes for this species. Because of the morphologic similarity between E. trentonensis and both Ulrich’s type material and other authors’ con- cepts of E. mutabilis, it is suggested that a reevaluation of Ulrich’s type material be made in light of both Karklin’s discriminating factors and H.A. Nicholson’s collection of E. trentonensis types (currently being studied by other workers—see discussion in Karklins, 1984). Distribution.—Localities NL IV, CB, HCM, WB. Studied material.—Hypotypes NL IV 61(96)A-4- F(M) [USNM 432407], NL IV 61(96)A-5-R(M) [USNM 432408], NL IV 61(96)A-4-K(M) [USNM 432409], NL IV 87(122)A-3B-B(M) [USNM 432410], NL IV 93(128)A-9-D(M) [USNM 432411], NL IV 93(128)A-14-E(M) [USNM 432412], NL IV 30(65)A- 1-A [USNM 432413], NL IV 30(65)A-3-B [USNM 432414], NL IV 33(68)A-1-B [USNM 432415], NL IV 37(72)B-4-D [USNM 432416], NL IV 43(78)B- 6L-KK [USNM 432417], NL IV 43(78)B-2-F [USNM 432418], NL IV 43(78)B-2-D [USNM 432419], NL IV 49(84)A-8RB-J [USNM 432420], NL IV 49(84)A- 6R-AA [USNM 432421], NL IV 50(85)A-4-B [USNM 432422], NL IV 51(86)A-5L-A [USNM 432423], NL IV 61(96)A-2-G [USNM 432424], NL IV 61(96)A- 4-C [USNM 432425], NL IV 61(96)A-7-C [USNM 432426], NL IV 61(96)A-5-A [USNM 432427], NL IV 61(96)A-5-D [USNM 432428], NL IV 61(96)A- 5-E [USNM 432429], NL IV 61(96)A-2-H [USNM 432430], NL IV 61(96)A-7-D [USNM 432431], NL IV 61(96)A-5-Q [USNM 432432], NL IV 61(96)A- 9-F [USNM 432433], NL IV 61(96)A-9-E [USNM 432434], NL IV 61(96)A-8-I,J [USNM 432435], NL IV 61(96)A-5-V [USNM 432436], NL IV 61(96)A-9-J [USNM 432437], NL IV 63(98)B-5LA-C [USNM 432438], NL IV 63(98)B-6LA-D,C [USNM 432439], NL IV 63(98)B-6LA-E [USNM 432440], NL IV 63(98)B-5LA-B [USNM 432441], NL IV 66(101)A- 7-E [USNM 432442], NL IV 85(120)A-3AR-C [USNM 432443], NL IV 85(120)A-10L-B [USNM 432444], NL IV 85(120)A-8L-D [USNM 432445], NL IV 85(120)A-9L-A [USNM 432446], NL IV 85(120)A-5L-F [USNM 432447], NL IV 85(120)A- 6L-D [USNM 432448], NL IV 85(120)A-5L-E [USNM 432449], NL IV 85(120)A-5L-C [USNM 432450], NL IV 85(120)A-6L-N,O,P [USNM 432451], NL IV 85(120)A-12L-B [USNM 432452], NL IV 85(120)A-6L-E [USNM 432453], NL IV 93(128)A- 3-H [USNM 432454], NL IV 93(128)A-4-M [USNM 432455], NL IV 94(129)A-2L-C [USNM 432456], NL IV 96(131)C-2-E [USNM 432457], NL IV 100(135)A- 5L-F [USNM 432458], NL IV 100(135)A-11L-B [USNM 432459], NL IV 100(135)A-6L-G [USNM 432460], NL IV 100(135)A-13L-I [USNM 432461], NL IV_ 116(151)A-5-C [USNM 432462], NL IV 117(152)A-8-A [USNM 432463], NL IV 117(152)A- 7-B [USNM 432464], NL IV 117(152)A-7-C [USNM 432465], NL IV 50(85)A-16-A(F) [USNM 432466], NL IV 51(86)A-7L(F) [USNM 432467], NL IV 51(86)A-7L-A,B(F) [USNM 432468], NL IV 63(98)B-LB-X(F) [USNM 432469], CB 45A-3-B(M) [USNM 432470], CB 138.5A-14-A(M) [USNM 432471], CB 153B-1-A(M) [USNM 432472], CB 41A-3-C [USNM 432473], CB 41A-3-A [USNM 432474], CB 41A-1-B [USNM 432475], CB 54A-4-A [USNM 432476], CB 55A-8-B [USNM 432477], CB 62A-11-A [USNM 432478], CB 67B-9-C [USNM 432479], CB 79B-2-A [USNM 432480], CB 82A-1-A [USNM 432481], CB 122A-21-B [USNM 432482], CB 132C-3-A [USNM 432483], CB 132C-3-B MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH Table 29.—Quantitative data, Heterotrypa rugosa n. sp. See Key to Abbreviations, p. 33, for explanation. Character Range ZCD INDSLV) ceccca cre .18—.25 TOTAL, iveasss .18—.25 ZCD (mac) INTSALV os sececics .25-.45 MOWAT eee. .25-.45 ZWT INTEL Scmccactes -02—.04 MOWAT secs .02—.04 ZWT (mac) INE es cise .02—.08 OWA eeceeee .02—.08 Z/mm? NUS EV) Saaerecncrs 18-24 TOTAL woes =<: 18-24 [USNM 432484], CB 145B-3-B [USNM 432485], CB 41B-1-A(F) [USNM 432486], CB 46B-3-A(F) [USNM 432487], CB 54A-3-B(F) [USNM 432488], CB 67B-6-E(F) [USNM 432489], CB 67B-9-D(F) [USNM 432490], CB 67B-6-F [USNM 432491], CB 67B-6-D(F) [USNM 432492], CB 76B-8-L-A(F) [USNM 432493], CB 82A-4-C(F) [USNM 432494], CB 85A-12L-A(F) [USNM 432495], CB 120A-5-A(F) [USNM 432496], CB 122A-1-A(F) [USNM 432497], CB 122A-6-B(F) [USNM 432498], CB 122A-24-A(F) [USNM 432499], CB 145B-3-C(F) [USNM 432500], CB 150B-3-B(F) [USNM 432501], CB 153A-4L-B(F) [USNM 432502], CB 153A-4L-A(F) [USNM 432503], HCM 43(82)C-5L-FF [USNM 432504], HCM 43(82)A-3-G [USNM 432505], WB 20(32)B- 4-A [USNM 432506], WB 44(56)B-2-C [USNM 432507]. Family HETEROTRYPIDAE Ulrich, 1890 Genus HETEROTRYPA Nicholson Type species.—Monticulipora frondosa d Orbigny, 1850. Heterotrypa rugosa, new species Plate 13, Figures 1—2 Description.—Zoaria ramose. Zooecia initiated mainly between middle to outer endozone. Zooecial cavity outline subpolygonal in exozone, polygonal in endozone. Zooecia curve quickly in outer endozone usually accompanied with distinctive zooecial bend found in lower exozone. After bend, zooecia continue directly to surface. Zooecia intersect colony surface at right angles. Walls gradually thicken in lower exozone before zooecial bend. After bend, exozonal wall thick- ness consistent outwards to slightly thickened and thinned. Walls composed of U- to V-shaped laminae. Endozonal walls characteristically largely crenulate, fairly parallel-sided. In places, walls beaded or ex- tremely crenulate. Endozone relatively wide. Dia- Mean NN oS) 35 35 03 03 04 04 67 Mode S.D. No. Meas. No. Spec. 22 -O1S 60 6 222 -015 60 6 .34 .036 56 6 34 .036 56 6 03 -006 60 6 -03 .006 60 6 03 O12 60 6 03 .012 60 6 21, 22 iLeS) 19 6 222 1.5 19 6 phragms in endozone, thin, planar, perpendicular to walls, spaced two to three zooecial cavity diameters apart. In outer endozone spaced at one and one-half zooecial cavity diameters apart. In lower exozone be- fore zooecial bend, spaced at one zooecial cavity di- ameter apart. In remaining exozone, diaphragms spaced at one-third to one-half zooecial cavity diam- eter apart. Exozonal diaphragms mainly perpendicular to zooecial walls, usually slightly bowed convex in- wards, sometimes inclined with or without overlap, slightly thicker than for endozone, thickness fairly consistent, diaphragm laminae clearly traceable into wall laminae. Mesozooecia rare, subpolygonal to sub- rounded, diaphragms thicker than for autozooecia, spaced at one mesozooecial cavity diameter. Mural la- cunae, infrequently distinct acanthostyles, common at zooecial corners in exozone. Large acanthostyles scat- tered in outer endozone. Maculae composed of large autozooecia, mesozooecia very few to absent, walls commonly slightly thicker than in non-macular areas. Etymology.—The name of the species rugosa is de- rived from the Latin rugosus meaning wrinkled, and refers to the crenulate endozonal walls and commonly unevenly thickened exozonal walls. Measurements.—Measurements are summarized in Table 29. Remarks.—Heterotrypa rugosa is characterized by the combination of subpolygonal exozonal zooecial cavity outlines, crenulate endozonal walls, relatively thin exozonal walls which are many times slightly thickened and thinned, common diaphragms through- out the zoarium that are spaced two to three zooecial cavity diameters apart within the endozone and one- third to one-half zooecial cavity diameters apart within the exozone where they are mainly perpendicular to the zooecial axis, usually slightly bowed convex in- wards and locally inclined to overlapping, rare meso- zooecia, scattered exozonal acanthostyles, mural la- 68 BULLETIN 353 cunae common at zooecial corners, and a relatively wide endozone. The present species is morphologically similar to Heterotrypa appressa (Ulrich). Differences exist in that H. rugosa has larger autozooecial cavity diame- ters, plentiful axial diaphragms, and a consistently closer spacing of diaphragms in the exozone. H. ru- gosa differs from Heterotrypa parvulipora Ulrich and Bassler in having larger zooecial cavity outlines in the exozone, a closer spacing of exozonal diaphragms which are commonly bowed convex inwards, and some slightly more distinctive acanthostyles. Hetero- trypa exovaria (new species designated herein) differs from H. rugosa in having greater numbers of sub- rounded zooecial cavity outlines, smaller autozooecial cavity diameters, thicker autozooecial exozonal walls which are irregularly thickened and thinned, more dis- tinct and regularly spaced acanthostyles, more meso- zooecia, endozonal styles with thicker laminae, and generally more variably oriented and irregularly spaced autozooecial diaphragms. On occasion, recrystallization will obliterate thin en- dozonal diaphragms of H. rugosa. Distribution.—Localities NL IV, CB. Studied material.—Holotype NL IV 108(143)A-15- A(M) [USNM 432508], Paratypes NL IV 96(131)F(M) [USNM 432509], NL IV 108(143)A-6-K(M) [USNM 432510], NL IV 108(143)A-14-L(M) [USNM 432511], NL IV 108(143)A-15-B(M,) [USNM 432512], NL IV 108(143)A-16-B(M) (USNM 432513], NL IV 116(151)A-5-B [USNM 432514], CB 132B-4-A [USNM 433074]. ?Heterotrypa subramosa (Ulrich, 1879) Plate 14, Figures 1—2 Atactopora subramosa Ulrich, 1879, p. 124, pl. 12, figs. 6—-6c. Heterotrypa prolifica Ulrich, 1890, p. 413, 414, pl. 37, figs. 1—-1d. Dekayia prolifica (Ulrich). Cumings, 1908, p. 820, 821, pl. 15, figs. 4—4b, pl. 29, fig. 3. Dekayia subramosa (Ulrich). Cumings, 1908, p. 823, 824, pl. 15, figs. 5—Sb, pl. 29, fig. 2. Heterotrypa subramosa (Ulrich). Utgaard and Perry, 1964, p. 78— 80, pl. 13, figs. 5—7, pl. 14, figs. 1-4. Description.—Zoaria ramose, encrusting. Zooecia initiated homogeneously throughout endozone. Zooe- cial cavity outlines subpolygonal to subrounded less commonly rounded in exozone, polygonal in endo- zone. Endozonal zooecia curve broadly outwards to zooecial bend at endozonal/exozonal transition or low- er exozone and continue directly outwards to intersect colony surface at nearly right angles. Exozonal walls irregularly thickened and thinned. Wall laminae U- to V-shaped. Endozonal walls even to slightly crenulate, fairly parallel-sided. Axial diaphragms (endozone) spaced approximately two to three zooecial cavity di- ameters apart sometimes absent to few within inner- most endozone. Autozooecial diaphragms thin, mainly perpendicular to zooecial axis, some inclined and/or slightly curved and sometimes overlapping. Dia- phragms in exozone evenly spaced commonly at about two-thirds of a zooecial cavity diameter apart (locally greater in a few instances), thin (slightly thicker than in endozone). Mesozooecia common in exozone. Some change to autozooecia (and vice-versa). Mesozooecial walls irregularly thickened and moniliform. Polygonal to subpolygonal in cross-sectional outline. Found be- tween many autozooecia but do not completely isolate them. Initiated at base of exozone and either continue to surface, terminate, or change into autozooecia. Me- sozooecial diaphragms, in general, thicker than for au- tozooecia, fairly evenly spaced about | mesozooecial cavity diameter apart, mainly perpendicular to walls with some slightly inclined. Sometimes autozooecia change gradually into mesozooecia zooecially out- wards. Acanthostyles mainly in exozone, sometimes in outer endozone where commonly forming the center of petaloid cluster of autozooecia. Diameters of styles (laminar sheath and clear axis) fairly consistent. Com- monly one to two, less commonly two to three sur- round each autozooecium and found between adjacent zooecia or at zooecial corners. Some exozonal styles found mostly between zooecia offset and inflecting. Poorly defined maculae present, many times with cen- tral mesozooecial cluster. Measurements.—Measurements are summarized in Table 30. Remarks.—?Heterotrypa subramosa is character- ized by subpolygonal to subrounded zooecial cavity outlines in exozone, endozonal diaphragms spaced two to three zooecial cavity diameters apart, more widely spaced to absent in innermost endozone, exozonal di- aphragms mainly oriented perpendicular to irregularly thickened and thinned zooecial walls and spaced at approximately two-thirds of a zooecial cavity diameter apart, common mesozooecia which are polygonal to subpolygonal in cavity outline shape, with irregularly thickened moniliform walls, most common in early exozone, one to three acanthostyles (commonly one to two) surrounding each autozooecium in the exozone, and some acanthostyles in the outer endozone. The present species differs from Heterotrypa ulrichi (Nicholson) primarily in having wider zooecial cavi- ties, and larger acanthostyle diameters (this is plainly observed in the figures of Cumings, 1908, pl. 14; Bass- ler, 1906, pl. 2; and Boardman and Utgaard, 1966, pl. 142). In addition, descriptions by Cumings (1908) and McFarlan (1931) indicate a sparsity of diaphragms in the endozone as a further differentiating factor. While MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH 69 Table 30.—Quantitative data, ?Heterotrypa subramosa (Ulrich). See Key to Abbreviations, p. 33, for explanation. Character Range Mean Mode S:D: No. Meas. No. Spec. ZCD INES’ siesite cde 15—.23 19 20 .O1S 75 8 MOWAT eee 15—.23 19 .20 O15 75 8 ZCD (mac) INDE SLIW) Fier ststcisisis .22—.32 28 30 .024 52 8 MOWAT Pascoe. .22—.32 28 30 .024 52 8 ZWT INI scnecte tise O1—.07 03 .02 OLS 80 8 MOMMA cece O1—.07 03 .02 OLS 80 8 Z/mm? INDIDV ee eenecaee 20-31 26 22, 26 3.9 8 8 OMA eras 20-31 26 22, 26 3.9 8 8 MxMCD INERUV SS sceeristoe .03-.17 09 09 .034 72 8 MOMAL Ys 5020s: .03-.17 09 09 .034 72. 8 MnMCD INTEND? cocennss .02—.13 .06 08 .024 72 8 MOA cess: .02-.13 .06 08 .024 72 8 AD (lam) INDE! ces cjeis esis.< .03-.12 .07 08 .020 78 8 TODAS <<... .03-—.12 .O7 08 .020 78 8 not describing H. ulrichi due, foremost, to the lack of 108(143)A-13-F(M) [USNM 432521], NL IV primary types and the inadequate occurrence data for 108(143)A-5-G(M) [USNM 432522], NL IV the primary types, Boardman and Utgaard (1966) do illustrate specimens considered by them to be topo- types. Their figures suggest that an additional charac- teristic of this species is the common offsetting nature of exozonal acanthostyles and relatively straighter and more regularly thickened zooecial walls. Cumings (1902, 1908) recognized Dekayella robus- ta Foord to be a varietal form of Dekayia ulrichi (=Heterotrypa ulrichi). Among the internal character- istics used to differentiate the two forms are greater numbers of both diaphragms and acanthostyles (his “spiniform corallites”’) in Dekayella robusta. Heterotrypa foliacea differs from ?H. subramosa in having generally fewer mesozooecia, more common and larger endozonal acanthostyles, somewhat smaller exozonal acanthostyles, and more prevalent straight and evenly thickened autozooecial and mesozooecial walls. Specimens assigned herein to ?Heterotrypa subra- mosa differ slightly from the description of other au- thors (see synonymy) in lacking concave outward ba- sal diaphragms and having more widespread and con- sistently developed irregularly thickened autozooecial and mesozooecial walls and moniliform mesozooecia. As a result, this material has not been definitively placed into this species. Distribution.—NL IV, CB. Studied material.—Hypotypes NL IV 108(143)A-6- A(M) [USNM 432515], NL IV_ 108(143)A-1-C(M) [USNM 432516], NL IV 108(143)A-5-F(M) [USNM 432517], NL IV 108(143)A-6-B(M) [USNM 432518] NL IV 108(143)A-7-C(M) [USNM 432519], NL IV 108(143)A-8-A(M) [USNM 432520], NL IV 94(129)A-2L-H [USNM 432523], NL IV 100(135)A- 12L-M [USNM 432524]. Heterotrypa subtrentonensis, new species Plate 16, Figures 1—2 Description.—Zoaria ramose. Zooecia initiate ho- mogeneously throughout endozone. Zooecial cavity outlines subrounded to subangular in exozone. Polyg- onal in endozone. Zooecia curve broadly in endozone, curve accelerated at endozonal/exozonal transition with or without zooecial bend in lower exozone, zooe- cia then continue directly outwards to intersect colony surface at or nearly at right angles. Endozonal walls commonly irregularly thickened and thinned, but many times thin and straight to occasionally flexuous, thick- en gradually from outermost endozone to lower exo- zone, either remain of even thickness outwards to col- ony surface or thin in outer exozone to give a pointed appearance to walls in longitudinal section (especially in zoaria with relatively wide exozone). Walls in out- ermost endozone and exozone composed mainly of U- to V-shaped laminae whose apices commonly con- nected by dark line. This line not evident in tangential section. Axial diaphragms thin, flat, perpendicular to zooecial walls, spaced mainly approximately one and one-half to two (or three maximum) zooecial cavity diameters apart. Exozonal diaphragms mainly perpen- dicular to zooecial walls, slightly thicker than for en- dozonal ones, commonly spaced one-third to one-half zooecial tube diameter apart; however, in some zoaria many inclined, overlapping, wavy, convex outwards or inwards. Some diaphragms of slightly greater individ- ual thicknesses and form distinct diaphragm-wall 70 BULLETIN 353 Table 31.—Quantitative data, Heterotrypa subtrentonensis n. sp. See Key to Abbreviations, p. 33, for explanation. Character Range ZCD NL IV 37-51 (72-86) .......... .20-.30 NL IV 94-116 (129-151) ...... .17—.32 INDE, DKON YANI EY eenenagbrassecosonsess .17-.32 (Ch Sj SY 7) aan Gonnaadennbacdnees .19—.28 CBrIB 8S 1545 wacceuewieemasenen: .16—.30 CBAVOMATE verncceeucerk acess .16—.30 BLOM (eascondnacconduonbosooannasens 19—.26 WW Boatarcicleinsiac tests sisiiotslesisisicreesisisreieie Ws 22-.31 WEST DOTA aa-nscrcccsecces .19-.31 OKO) WAN bee speunncensnseodgacconsds .16—.32 ZWT NL IV 37-S1 (72-86) .......... 02—.09 NL IV 94-116 (129-151) ...... 02—.09 INTE MOA eos sascisotcetee ne iteeterer 02—.09 EBSA 72) oo crcciieieassis siisincetstereeris .03—.09 CBeSS SALSA ie ace cece seer .02—.16 GBUTODAL re iseiseiissiescinesaoster 02-—.16 FIOM Soar nsitsis secionso cnceeiiewerstence 04—.07 WB) Sh .ctcisceee ceucighea ci santeiercomeinen .03—.08 AEST GNOME, CS aeeeocacousscae 03-.08 IHONUN De tonaepoonceunerdcaccdsenne .02—.16 Z/mm? NEV IV 37=Sl) (72=86)) scipg 2 - te 3G ie ey " excQSS@33~ Sa acetl SEIS a Stee NS a a | Dre aN - ~~ BULLETINS OF AMERICAN PALEONTOLOGY, WOLUME 112 PLATE 6 Figure 1-2. Homotrypa minnesotensis Ulrich la. Ie. 2: MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH EXPLANATION OF PLATE 6 Longitudinal section showing zooecia intersecting surface at less than 90°, even, crenulate and beaded autozooecial walls in endozone, megazooecium within inner endozone, laminar zooecial walls in exozone, diaphragms absent within endozone except for very outermost endozone, and exozonal zooecia with mainly inclined and curved diaphragms with or without cystiphragms, Hypotype USNM 431883 [CB 145C-4-D], 25. . Tangential section showing subpolygonal to subrounded zooecial cavity outlines, minute acanthostyles or acanthostyle-like openings at many zooecial corners, and distinctive maculae composed of megazooecia and some mesozooecia, Hypotype USNM 431883 [CB 145C-4-D], 45. Longitudinalsection of outer exozone showing wall microstructure of distinct U- to V-shaped laminae, Hypotype USNM 431883 (CB 145C-4-D], x 100. Transverse section showing polygonal zooecial cavity outlines in endozone, Hypotype USNM 431872 [NL IV 43(78)B-6L-R], «40. [EOL OTIR TREO ARATE OS oa Gold Eos CSO ClG 1D. OENDLO ONG OCU CIGRCHEREL CICA CRCHORCRCRCI COR CMe occ NCNChcE RCM ME ican caceck eee oe ence eee 3a. 3b. Bc; 3d. Tangential section showing laminar walls, slightly elongate subrounded to subpolygonal zooecial cavity outlines, a macula in upper right of figure composed of both megazooecia and mesozooecia, and minute acanthostyles at and between zooecial corners, Holotype USNM 432039 [CB S50A-4-A], X45. Longitudinal section showing an oblique zooecial surface angle, relatively thin exozonal walls, even to slightly crenulate zooecial walls in endozone, endozonal megazooecia which are constricted at base of exozone, exozonal diaphragms which are regularly spaced and perpendicular or inclined to zooecial walls and curved convex outwards, and endozonal diaphragms (arrows). Here, diaphragms of the inner endozone are absent in top half of figure probably due to effects of recrystallization. Other colonies of this species show diaphragms to be generally present throughout entire endozone, Holotype USNM 432039 [CB 50A-4-A], X25. Longitudinal section of exozone showing laminar wall microstructure, Holotype USNM 432039 [CB S50A-4-A], 100. Transverse section across endozone showing polygonal zooecial cavity outlines, Holotype USNM 432039 [CB 50A-4-A], 40. 99 49 100 BULLETIN 353 EXPLANATION OF PLATE 7 Figure 1-2. Homotrypa tuberculata NOMIC) ri... ssid eusvas isco eite, eh 28nd fe tle sale Gates) 1 Gua mere EE ROT ee eae la. Transverse section showing polygonal zooecial cavity outlines in endozone, Hypotype USNM 432082 [HCM 43(82)B-4-G], «40. lb. Tangential section showing subrounded to rounded autozooecial cavity outlines, laminar walls, small polygonal mesozooecia, and distinct, commonly inflecting, sometimes offset acanthostyles, Hypotype USNM 432082 [HCM 43(82)B-4-G)], x45. lc. Longitudinal section showing a fairly sharp zooecial bend in the lower exozone, a generally short exozone with diaphragms which are variable in number, orientation, spacing and thickness, diaphragms in the endozone found only in the outermost portions, irregularly overlapping exozonal cystiphragms of variable number and thickness, small mesozooecia, and common acanthostyles, Hypotype USNM 432082 [HCM 43(82)B-4-G], x25. 2a. Longitudinal section as for Figure 1c, Hypotype USNM 432058 [CB 85A-6-C], 25. 2b. Tangential section as for Figure 1b, Hypotype USNM 432058 [CB 85A-6-C], 45. 2c. Longitudinal section of exozone showing wall microstructure with generally V-shaped laminae, Hypotype USNM 432058 [CB 85A-6-C], «100. Fomotry pat similisROord (5 .3i citensi svi les o's erersns aueeeure iaete cies sale, eS! Sise Noll scsc s) epkch sees Rite (ae ea RE ane 3a. Longitudinal section of exozone showing autozooecial walls with a generally non-laminar appearance. A somewhat more laminar microstructure is associated with an acanthostyle to top of figure, Hypotype USNM 432025 [NL IV 108(143)A-8-D], «100. 3b. Transverse section of endozone showing polygonal zooecial cavity outlines, Hypotype USNM 432025 [NL IV 108(143)A-8- D], X40. 3c. Longitudinal section showing a narrow exozone, shallow surface angle, megazooecia in the center of the endozone, diaphragms in the outer endozone and exozone, and overlapping exozonal cystiphragms, Hypotype USNM 432025 [NL IV 108(143)A-8- DD RexX25: 3d. Tangential section showing elongate subrounded to subpolygonal zooecial cavity outlines, and a macula in lower center of figure composed of megazooecia and a few mesozooecia. Scattered throughout are small acanthostyles somewhat obscured due to low surface angle, Hypotype USNM 432025 [NL IV 108(143)A-8-D)], x45. 48 BULLETINS OF AMERICAN PALEONTOLOGY, WOLUME 112 PLATE 7 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 112 PLATE 8 Figure MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH EXPLANATION OF PLATE 8 vst, Gian? elegy UU sob acnp ope ob and oo Boo 8 amb hoo oa oeaoS oie ces corn mie Seer om neo Gitvoros od boo ocuree Saree sic la. 1b. Ic. tN Longitudinal section showing evenly curving zooecia, fairly regularly spaced diaphragms throughout colony mainly perpendic- ular to zooecial walls, and overlapping cystiphragms, Hypotype USNM 432095 [NL IV 96(131)B-2-J], x25. Longitudinal section showing predominantly granular wall microstructure with some poorly defined U-shaped laminae in places, Hypotype USNM 432095 [NL IV 96(131)B-2-J], «100. Tangential section showing subpolygonal to subrounded zooecial cavity outlines, a macula in upper left of figure composed of megazooecia and small subrounded to subangular mesozooecia, and scattered and inconspicuous acanthostyles, Hypotype USNM 432095 [NL IV 96(131)B-2-J], x45. . Transverse section of endozone showing polygonal zooecial cavity outlines, Hypotype USNM 432096 [NL IV 100(135)A-13L- F], X40. S. [RUNTTAVEE Fbe BN oc ck cota S keep Ac oa ues AC OOO OU OE I Oe On dem Op aD Be 0G do 615 Co BS ciolnia Om inico.d ko cud o.oo eC 3a. 3b. Sc: 3e. Transverse section across endozone showing polygonal zooecial cavity outlines and megazooecia mainly within the inner endozone, Hypotype USNM 432172 [NL IV 108(143)A-14-N], 40. Tangential section showing portions of the zoarium having thick and thin exozonal walls, subpolygonal to polygonal zooecial cavity outlines where walls are narrow, and acanthostyles at and between zooecial corners which inflect where walls are thin, Hypotype USNM 432172 [NL IV 108(143)A-14-N], <45. Longitudinal section showing an autozooecial wall microstructure composed of distinct laminae, Hypotype USNM 432172 [NL TV 108(143)A-14-N], x 100. . Tangential section showing characteristically thick zooecial walls, subrounded to subpolygonal zooecial cavity outlines, and acanthostyles at and between zooecial corners, Hypotype USNM 432172 [NL IV 108(143)A-14-N], 45. Longitudinal section showing laminar wall structure, diaphragms limited mainly to both outermost endozone and exozone, exozonal diaphragms commonly inclined and planar to curved convex outwards, scattered cystiphragms and cystose diaphragms, megazooecia within inner endozone, wavy, crenulate and beaded endozonal walls, and acanthostyles, Hypotype USNM 432172 [NL IV 108(143)A-14-N], X25. 101 Page 55 102 Figure BULLETIN 353 EXPLANATION OF PLATE 9 I=5 HOMO DA SUDrAMNOSA! WITCH v..5:002 f y -* ? 5 LAY Se LAA Figure NSS. WV OTOL EAN TORSO NS. Sie eno EGE y Stee EREIENE Lo Pie) A cL - aa thon CaO nene © ies cic act OnCueh CRE RCE IM Lote ecto nn BROEE a en AaenS | inom. arin ase la. 4b. Sa. Sb. 6a. 6b. MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH EXPLANATION OF PLATE 10 Longitudinal section showing thin and granular walls, planar diaphragms, and overlapping cystiphragms, Hypotype USNM 432173 [NL IV 72(107)B-4L-A], X45. . Tangential section showing subpolygonal zooecial cavity outlines, thin and granular walls, and small acanthostyles on left side of figure. On right side is a deeper tangential cut showing a lack of styles and increased intrazooecial structures, Hypotype USNM 432173 [NL IV 72(107)B-4L-A], X45. lc. Longitudinal section showing granular wall microstructure, Hypotype USNM 432173 [NL IV 72(107)B-4L-A], «100. 2a. Tangential section showing subpolygonal zooecial cavity outlines, granular walls, and small acanthostyles, some offset and inflecting, Hypotype USNM 432175 [NL IV 43(78)B-S5-N], x45. . Longitudinal section, slightly oblique, showing thin and granular walls, overlapping cystiphragms, planar to slightly bowed diaphragms, and small acanthostyles, some inflecting, Hypotype USNM 432175 [NL IV 43(78)B-5-N], 45. . Longitudinal section showing thin and granular walls and small acanthostyle near center of figure, Hypotype USNM 432174 [NL IV 85(120)A-3BR-A], 100. _ ESD AAT TT! (WRITES) 5 6 alee, oodS iar bs (oie) 0 ia Deo Ge, Onna cD CEO Sit oS RENEE Oe Coed ae Gs CRONE Orde o re hots omit Aire eas 4a. Longitudinal section showing wall thickness gradually increasing zooecially outwards, and wall laminae more poorly defined than typical for species (cf. Figure 6a), Hypotype USNM 432179 [NL IV 44(79)A-14LA-D], 100. Tangential section showing typical elliptical autozooecial cavity outlines, thick walls, and numerous small acanthostyles, Hy- potype USNM 432179 [NL IV 44(79)A-14LA-D], x45. Longitudinal section showing a slender ramose branch, low surface angle, narrow exozone, relatively thick and laminar exozonal walls, and rare diaphragms, Hypotype USNM 432176 [NL IV 30(65)A-1-B], 25. Tangential section showing elliptical to subrounded or rounded autozooecial cavity outlines, thick walls, scattered small diameter autozooecia caused by a cut through local zones of constriction (see Remarks section of Systematic Paleontology), and common small acanthostyles, Hypotype USNM 432176 [NL IV 30(65)A-1-B], *45. Longitudinal section showing a rare diaphragm and wall microstructure composed of U- to V-shaped laminae with a dark median line, Hypotype USNM 432191 [NL IV 93(128)A-2-I], «100. Transverse section showing a narrow exozone, polygonal zooecial cavity outlines in endozone, and a megazooecium and pseudoradial arrangement of zooecia within the inner endozone, Hypotype USNM 432191 [NL IV 93(128)A-2-I], 25. 103 Si) 104 BULLETIN 353 EXPLANATION OF PLATE 11 Figure l—4SBatostomella subsracilis (UInICn) <<, 5 eke a, ae tee eee tao) asco nel aera ancrao eat anes Be ReRRE Hee amet tale fone cee cn ee ee a la. Longitudinal section showing fairly thick and laminar exozonal walls with a dark median line, lack of diaphragms, and oblique surface angles. Note the irregular thickening of some exozonal walls, Hypotype USNM 432313 [NL IV 93(128)A-3-K], x 25. lb. Longitudinal section showing U-shaped laminae of autozooecial walls, Hypotype USNM 432313 [NL IV 93(128)A-3-K], x 100. lc. Tangential section showing elliptical autozooecial cavity outlines and minute acanthostyles. Smaller autozooecial openings are products of local outer wall thickening and are not true mesozooecia, Hypotype USNM 432313 [NL IV 93(128)A-3-K], x45. . Transverse section showing a megazooecium in inner endozone, Hypotype USNM 432335 [NL IV 93(128)A-9-C], x40. . Transverse section showing a pseudoradial arrangement of relatively small endozonal zooecia, Hypotype USNM 432324 [NL IV 100(135)A-9L-NN], 40. 4. Transverse section of endozone showing typical polygonal zooecial cavity outlines, Hypotype USNM 432332 [NL IV 93(128)A- 2-G], X40. Batostomellarsuberactlish (Wlrich)) VaryrODUsta env ater eiey el elite lcitsice vent) ieee vie acne aoe enone eae en ae Sa. Tangential section showing similarity of appearance to non-varietal form of the species, Hypotype USNM 432395 [NL IV 108(143)A-1-B], x45. Sb. Longitudinal section showing U-shaped laminae of autozooecial walls, Hypotype USNM 432395 [NL IV 108(143)A-1-B], 100. 5c. Longitudinal section showing exceedingly wide exozone, otherwise being similar to non-varietal form of B. subgracilis, Hy- potype USNM 432395 [NL IV 108(143)A-1-B], x14. why 63 PLATE 11 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 112 PLATE 12 BULLETINS OF AMERICAN PALEONTOLOGY, WOLUME 112 Figure 1-2. Batostomella subgracilis (Ulrich) var. robusta n. var. 3-4. la. te MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH EXPLANATION OF PLATE 12 Tangential section similar to non-varietal form of the species showing elliptical autozooecial cavity outlines and minute acan- thostyles. Smaller autozooecial openings are products of local outer wall thickening and are not true mesozooecia, Hypotype USNM 432399 [NL IV 108(143)A-1-G)], 45. . Transverse section showing pseudoradial arrangement of zooecia within inner endozone, Hypotype USNM 432399 [NL IV 108(143)A-1-G], 25. . Transverse section showing larger zooecia within inner endozone than for outer endozone, Hypotype USNM 432406 [NL IV 108(143)A-18-B], X25. [D[slsinyae iiGui ty UME 2 oa6 ofa nook DES Ooh Oos DOO OOM MOO Om cid mmo Aco opm cmp seo bass os Oo pKe 3a. 3b. 3c. 3d. da. 4b. Longitudinal section showing low surface angles, thick laminar autozooecial walls in exozone, subparallel zooecia in endozone, megazooecia within innermost endozone, diaphragms perpendicular to zooecial walls in outer endozone and exozone, and few exozonal mesozooecia, Hypotype USNM 432443 [NL IV 85(120)A-3AR-C], X25. Longitudinal section of exozone showing wall microstructure of broad U- to V-shaped laminae, Hypotype USNM 432443 [NL IV 85(120)A-3AR-C], 100. Tangential section displaying thick laminar walls, elliptical zooecial cavity outlines, subrounded to ovate mesozooecial cavity outlines, and minute acanthostyles, Hypotype USNM 432443 [NL IV 85(120)A-3AR-C], *45. Transverse section of endozone showing polygonal zooecial cavity outlines. Note that endozonal cavities narrow from innermost endozone (lower left of figure) towards inner exozone, Hypotype USNM 432443 [NL IV 85(120)A-3AR-C], *40. Tangential section of an ontogenetically advanced colony showing many subrounded to subpolygonal zooecial cavity outlines more direct than typical for the species, very thick walls, large laminar sheaths of acanthostyles, and a macula in upper left corner of figure, Hypotype USNM 432407 [NL IV 61(96)A-4-F], X45. Longitudinal section as for Figure 3b, Hypotype USNM 432407 [NL IV 61(96)A-4-F], * 100. 105 64 106 Figure 1-2. Heterotrypa rugosa n. sp la. BULLETIN 353 EXPLANATION OF PLATE 13 Tangential section showing subpolygonal zooecial cavity outlines, a macula in lower center of figure and composed of distinct megazooecia and a mesozooecium, mural lacunae at zooecial corners, and uncommon acanthostyles, Holotype USNM 432508 [NL IV 108(143)A-15-A], X25. . Longitudinal section showing autozooecial walls composed of U- to V-shaped laminae, Holotype USNM 432508 [NL IV 108(143)A-15-A], 100. . Longitudinal section showing relatively thin autozooecial walls in exozone, fairly consistent in thickness, locally thickened and thinned slightly, autozooecial walls in endozone commonly crenulate (upper left corner of figure) and locally beaded, pervasive diaphragms usually perpendicular to zooecial walls, in exozone many bowed convex inwards and distinctly traceable into surrounding walls, and large endozonal acanthostyle to the top of the figure, Holotype USNM 432508 [NL IV 108(143)A-15- A], X25. . Transverse section showing polygonal endozonal zooecial cavity outlines. Crenulate nature of endozonal walls as observed in longitudinal section is reflected here in unevenness of the cavity walls, Holotype USNM 432508 [NL IV 108(143)A-15-A], «40. . Longitudinal section showing relatively thin autozooecial walls in exozone, commonly irregularly thickened and thinned slightly, mostly crenulate and locally beaded autozooecial walls in endozone, diaphragms throughout mainly perpendicular to zooecial walls, locally inclined and overlapping, somewhat thinner and less regularly spaced than typical for the species as a whole, Paratype USNM 432510 [NL IV 108(143)A-6-K], 25. . Longitudinal section showing endozone with commonly crenulate and locally beaded walls, and regularly spaced diaphragms, Paratype USNM 432510 [NL IV 108(143)A-6-K], X25. . Tangential section showing subpolygonal zooecial cavity outlines, mural lacunae at zooecial corners, maculae, and scattered acanthostyles slightly more numerous than generally typical for the species, Paratype USNM 432510 [NL IV 108(143)A-6-K], X25. . Enlarged portion of Figure 2c, Paratype USNM 432510 [NL IV 108(143)A-6-K], *45. BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 112 PLATE 13 BULLETINS OF AMERICAN PALEONTOLOGY, WOLUME 112 PLATE 14 oa »- Pa ade 4 )) oe j A a. vA fy Figure MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH EXPLANATION OF PLATE 14 LE PRPETCLOLO VAN SUD CIILO SC (CLERC) lateae iio) akc he 3c =: cat gs SAS Uz ee) ua sence eaes) Gd -UeP SAG) @ ele Neha 2 eticsy sceeh alten pele sy theta alicia eR SUA cee la. Longitudinal section showing diaphragm spacing in lower exozone greater than usual for the species, irregularly thickened and thinned autozooecial walls which themselves are thin, common moniliform mesozooecia of variable width in the exozone, some coalescing, diaphragms mainly perpendicular to the zooecial axis, and acanthostyles within the outermost endozone and exozone, Hypotype USNM 432519 [NL IV 108(143)A-7-C], 25. . Tangential section showing subpolygonal to subrounded and rounded autozooecial cavity outlines, polygonal to subpolygonal mesozooecial cavity outlines, and a moderate number of acanthostyles throughout zoarium, Hypotype USNM 432519 [NL IV 108(143)A-7-C], X25. . Tangential section showing common subpolygonal zooecial cavity outlines with fewer more rounded apertures, polygonal to subpolygonal mesozooecial cavity outlines, and a moderate number of evenly distributed acanthostyles at and between zooecial corners. Note that styles between zooecial corners commonly inflect contiguous zooecia, Hypotype USNM 432515 [NL IV 108(143)A-6-A], X45. . Longitudinal section showing irregularly thickened and thinned exozonal walls having a microstructure of distinct U-to V-shaped wall laminae, Hypotype USNM 432515 [NL IV 108(143)A-6-A], < 100. . Transverse section of endozone showing polygonal zooecial cavity outlines. Acanthostyles scattered mainly within outer en- dozone, Hypotype USNM 432515 [NL IV 108(143)A-6-A], x40. . Zooecial and mesozooecial cavity outlines, and acanthostyles as for Figure 2a. Note the megazooecia associated with an indistinct macular area near upper center of figure, and commonly petaloid arrangements of zooecia around acanthostyles in endozone in lower left of figure, Hypotype USNM 432515 [NL IV 108(143)A-6-A], 25. . Longitudinal section showing irregularly thickened and thinned laminar walls, diaphragms in autozooecia of outer endozone and exozone fairly regularly spaced and mainly perpendicular to zooecial walls, common mesozooecia in exozone with relatively thick and evenly spaced diaphragms and broadly moniliform walls, and acanthostyles, Hypotype USNM 432515 [NL IV 108(143)A-6-A], X25. 107 108 Figure BULLETIN 353 EXPLANATION FOR PLATE 15 l—4! Hl eterotrypa) CXxOVAFIa NSP: home revs oaks one cre «need soles whee. eyiciPas'*) estate na, ie oop «Ber Ree hee ele sy ease one ae eee ea ee eee la. Wh 4a. 4b. Longitudinal section showing generally planar diaphragms perpendicular to zooecial walls in endozone, perpendicular to inclined slightly in exozone, unevenly thickened exozonal walls, a mesozooecium (lower left corner of figure), common exozonal acanthostyles and a few acanthostyles in outer endozone, Holotype USNM 432640 [NL IV 94(129)A-4L-D], x25. . Transverse section showing polygonal zooecial cavity outlines in endozone. Acanthostyles found mainly in outer endozone (bottom half of figure), Holotype USNM 432640 [NL IV 94(129)A-4L-D], x40. . Longitudinal section of exozone showing unevenly thickened and thinned autozooecial walls having poorly defined wall laminae, Holotype USNM 432640 [NL IV 94(129)A-4L-D], x 100. . Tangential section showing subpolygonal to subrounded zooecial cavity outlines, few small commonly subangular mesozooecia, and ubiquitous acanthostyles found mainly at zooecial corners, Holotype USNM 432640 [NL IV 94(129)A-4L-D], *33. . Transverse section of endozone showing polygonal zooecial cavity outlines, Paratype USNM 432643 [NL IV 96(129)H], *40. . Oblique section through endozone showing large acanthostyles forming petaloid arrangements with surrounding autozooecia, Paratype USNM 432645 [NL IV 108(143)A-6-J], «33. Longitudinal section showing a relatively wide exozone, irregularly thickened and thinned autozooecial walls, variably oriented diaphragms, a few scattered mesozooecia, and acanthostyles (some inflecting), Paratypes USNM 432644 ({NL IV 96(131)F-1- D], X25. Longitudinal section showing endozone and lower exozone of specimen in Figure 4a. Note the conspecific growth within exozone in top left corner of figure, Paratype USNM 432644 [NL IV 96(131)F-1-D], 25. . Tangential section showing subpolygonal to subrounded autozooecial cavity outlines, a few mesozooecia, and common small acanthostyles, Paratype USNM 432644 [NL IV 96(131)F-1-D], 33. BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 112 PLATE 15 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 112 PLATE 16 Figure MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH EXPLANATION OF PLATE 16 aE IELEL OLY POISUDITCTHOICTISIS IIS SP 0-5. cy We We gelenobed oe cage ead oueahs Paeises enters Sie ysic=s Bufes ee Sh nls) Splensel Bil tains al er euits ead al ieee dee ome Seyetigcete eis la. Longitudinal section showing irregular thickening and thinning of autozooecial walls in endozone, narrowing of laminar auto- zooecial walls near colony surface to give a “pointed’”’ appearance, zooecial boundaries denoted by a dark line, endozonal diaphragms throughout, exozonal diaphragms thicker and mainly perpendicular to zooecial walls but many inclined, curved, or overlapping, and with thickest diaphragms forming parts of diaphragm-wall units, Holotype USNM 432525 [NL IV 116(151)A- 3-A], X25. . Longitudinal section showing an exozonal wall microstructure of distinct U- to V-shaped laminae. Note diaphragm-wall units where diaphragms thick, Holotype USNM 432525 [NL IV 116(151)A-3-A], 100. . Tangential section cutting through portions of a colony with thick and thin walls. In the latter instance, acanthostyles are somewhat inflecting, Holotype USNM 432525 [NL IV 116(151)A-3-A], x33. . Transverse section showing irregular thickening of some autozooecial walls in endozone, Holotype USNM 432525 [NL IV 116(151)A-3-A], x40. . Tangential section showing subrounded to subangular zooecial cavity outlines, a lack of mesozooecia, and acanthostyles with small cores common and mainly at zooecial corners, Holotype USNM 432525 [NL IV 116(151)A-3-A], 33. . Transverse section of endozone showing polygonal zooecial cavity outlines, Paratype USNM 432569 [CB 1S50B-4-A], *40. De LEV ROVE AVED! CRETE Dy, SOS ss GS ey AOE Fe RE TC SEP EER Bert tere ei ce ea irene tacnne a Rea gts Sf Tangential section showing subpolygonal to subrounded autozooecial cavity outlines, a few small mesozooecia, small acan- thostyles, and a poorly defined macula in left center of figure, Paratype USNM 432643 [NL IV 96(131)H], *33. 109 110 Figure ile BULLETIN 353 EXPLANATION OF PLATE 17 IS AAOMS NO ULES GO) ROI I Gon aeadanoenRoodscpuOe ood oon nO ONNUOUN DOD ADO o oo OND ODDS DODD ODE GOSS MED OD ee OOS la. le. selleterotrypa)praenuntia Var sunplex: (Wilrich) ssc. anette rae ee) eee eine) eee nee eee ene ea oe en 2a. 2b. 2c. 2d. 3a. . Longitudinal section as for Figure 2d but showing a large acanthostyle within endozone (arrow) and fewer exozonal acanthostyles, Longitudinal section showing large zooecia, irregularly thickened and thinned autozooecial walls in exozone composed of U-shaped laminae and containing acanthostyles, planar and evenly spaced exozonal diaphragms perpendicular to walls and usually forming distinct diaphragm-wall units, and relatively thick diaphragms at base of exozone, Holotype USNM 432591 [CB 72A-1-A], *25. . Portion of endozone from same zoarium as in Figure la, Holotype USNM 432591 [CB 72A-1-A], X25. >. Longitudinal section of exozone showing autozooecial walls composed of distinct U-shaped laminae, Holotype USNM 432591 [CB 72A-1-A], 100. . Tangential section showing large subrounded zooecial cavity outlines, fairly thick laminar walls, and common acanthostyles found at and between zooecial corners, Holotype USNM 432591 [CB 72A-1-A], 45. Transverse section showing polygonal zooecial cavity outlines of endozone, Holotype USNM 432591 [CB 72A-1-A], x40. Transverse section showing polygonal endozonal zooecial cavity outlines, Hypotype USNM 432653 [NL IV 108(143)A-5-D], x40 Longitudinal section showing distinct U- to V-shaped laminae of autozooecial walls, Hypotype USNM 432653 [NL IV 108(143)A- 5-D], 100. Tangential section showing subpolygonal zooecial cavity outlines, relatively thin walls, scattered acanthostyles, and possibly mural lacunae at many zooecial corners, Hypotype USNM 432653 [NL IV 108(143)A-5-D], 33. Longitudinal section showing slightly uneven exozonal walls, autozooecial walls in endozone crenulate (and beaded) in places, fairly consistently spaced exozonal diaphragms oriented mainly perpendicular to zooecial walls, commonly bowed convex outwards slightly, thin and planar endozonal diaphragms at right angles to walls, and some relatively thick walled acanthostyles (arrows) in area of zooecial bend found within lower exozone, Hypotype USNM 432653 [NL IV 108(143)A-5-D], x25. Tangential section as for Figure 2c but for a lack of acanthostyles, Hypotype USNM 432649 [NL IV 108(143)A-3-F], 33. Hypotype USNM 432649 [NL IV 108(143)A-3-F], x25. 74 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 112 PLATE 17 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 112 PLATE 18 Figure Be EETeLeR OLY Nagy CENUNIGWALLECHINGAIG! (WITICM))™ ues far 22s aps sa cvs iia) cu cic uel re ere NENG) 54) 35-o Rubra Nce 2 Sak Wet Aral eee OPI RN ote toe la. 4. Sa. 6a. 6b. MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH EXPLANATION OF PLATE 18 Longitudinal section very similar to H. praenuntia var. simplex (cf. Pl. 17, Fig. 3b) but for an abundance of large acanthostyles in exozone, Hypotype USNM 432690 [WB 20(32)B-2-B], X25. . Transverse section showing relatively large endozonal acanthostyles in center of petaloid clusters of zooecia, and polygonal zooecial cavity outlines, Hypotype USNM 432690 [WB 20(32)B-2-B], x40. . Tangential section showing large acanthostyles surrounded by petaloid arrangement of autozooecia, thin walls, and polygonal zooecial cavity outlines, Hypotype USNM 432690 [WB 20(32)B-2-B], x33. . Tangential section very similar in appearance to H. praenuntia var. simplex (cf. Pl. 17, Fig. 2c) but for large acanthostyles, Hypotype USNM 432672 [NL IV 93(128)A-9-F], x33. . Longitudinal section of an encrusting form showing acanthostyles with more pronounced wall laminae, and a somewhat greater spacing of diaphragms than found in H. praenuntia var. simplex, Hypotype USNM 432672 [NL IV 93(128)A-9-F], 25. . Longitudinal section showing V-shaped laminae of autozooecial wall in exozone, Hypotype USNM 432685 [CB 67B-7-D], x 100. . Tangential section showing thin walls, relatively large acanthostyles, and polygonal zooecial cavity outlines, Hypotype USNM 432685 [CB 67B-7-D], 33. MSN PRON NPOLACEY VILLOSAy UIUIGI) ewes ane sercak cotton eee isc op Sc oer oh elses Sule eek as eee SLia Magee: Shay ISL Wane een, ey re Lae Transverse section of endozone showing polygonal zooecial cavity outlines, Hypotype USNM 432692 [NL IV 43(78)B-4L-D], x40. Longitudinal section of subglobular encrusting form showing thin, even walls, diaphragms thin, planar and commonly perpen- dicular to walls, and small acanthostyles found where walls thicken slightly, Hypotype USNM 432696 [NL IV 66(101)A-SA- A], X25. . Tangential section showing very thin walls, polygonal zooecial cavity outlines, infrequent, minute acanthostyles and common mural lacunae (arrows) at zooecial corners, Hypotype USNM 432696 [NL IV 66(101)A-S5A-A], X33. Longitudinal section of a ramose colony showing thin and relatively widely spaced diaphragms throughout oriented perpendicular to zooecial walls and sometimes bowed convex outwards in exozone, thin walls even to slightly crenulate in endozone, and a surficial angle of 90°, Hypotype USNM 432695 [NL IV 49(84)A-4L-A], X25. Tangential section showing polygonal zooecial cavity outlines, thin walls, and common mural lacunae (arrows) and sparse small acanthostyles at zooecial corners, Hypotype USNM 432695 [NL IV 49(84)A-4L-A], «33. Longitudinal section of exozone showing wavy exozonal walls composed of V-shaped laminae, Hypotype USNM 432695 [NL IV 49(84)A-4L-A], 100. 111 UT 112 Figure BULLETIN 353 EXPLANATION OF PLATE 19 1=3° (Stiematella: distinctaspinosa’ D.. SP%- 52 cise, sue. seis ae hee eee Sree eile, 21S Be el ee Nene) ey SLT) Suen eS Re eRe on eT ee a en ae la. Ib. 3b. Longitudinal section showing numerous large acanthostyles, and thin and relatively widely spaced diaphragms perpendicular to thin walls, Paratype USNM 432709 [NL IV 117(152)A-8-D], X25. Tangential section, oblique, showing polygonal to subpolygonal zooecial cavity outlines, thin walls, and large inflecting acan- thostyles in shallowest tangential section on right side of figure and decreasing diameters to the left where zooecia are cut closer to colony base, Paratype USNM 432709 [NL IV 117(152)A-8-D], *33. . Longitudinal section of a specimen with a conspecific overgrowth showing thin walls, large acanthostyles, and thin, planar, and relatively widely spaced diaphragms perpendicular or inclined slightly to zooecial walls, Holotype USNM 432707 [NL IV 50(85)A-13-B], 25. . Longitudinal section showing thin wall separating adjacent autozooecia and acanthostyles with thick laminar sheaths, Holotype USNM 432707 [NL IV 50(85)A-13-B], 100. . Tangential section, oblique, showing numerous inflecting acanthostyles and decreasing diameters of zooecia with a deeper cut near colony base in bottom of figure. Note that largest styles are found at zooecial corners with smaller acanthostyles generally occurring between zooecia, Holotype USNM 432707 [NL IV 50(85)A-13-B], *25. . Longitudinal section showing very thin diaphragms, many inclined and/or curved, and numerous acanthostyles, Paratype USNM 432744 [CB 145C-4-C], «33. Tangential section showing plentiful inflecting acanthostyles at and between zooecial corners, some offset, Paratype USNM 432744 [CB 145C-4-C], «33. Page 77 PLATE 19 VOLUME 112 BULLETINS OF AMERICAN PALEONTOLOGY, BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 112 PLATE 20 Figure MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH EXPLANATION OF PLATE 20 eZ TI LEP IAE LEO IIICLEVIZILLL ELD LLQLCL (UW ITACED) dete (2533-3) Fe een cute ey Bote) Soc vanet Sogn ai ec. &. augue due apetarsiG ch tans neal she eect Ree la. 1b, lc. Tangential section showing subrounded to subpolygonal zooecial cavity outlines, and few small mesozooecia with subpolyg- onal to polygonal cavity outlines, Hypotype USNM 432772 [NL IV 96(131)E-1-B], <33. Longitudinal sections showing laminar walls with a faint dark line defining zooecial boundaries, diaphragms throughout colony, within endozone diaphragms most closely spaced at proximal-most parts of zooecial tubes, planar exozonal dia- phragms closely spaced, mainly perpendicular or somewhat inclined to zooecial walls and of variable thickness, and small exozonal mesozooecia cut obliquely in lower exozone with closely spaced diaphragms having thicknesses not greater than for autozooecia, Hypotype USNM 432772 [NL IV 96(131)E-1-B], 25. . Longitudinal section of outer exozone showing wall microstructure of mostly V-shaped laminae, Hypotype USNM 432772 [NL IV 96(131)E-1-B], * 100. . Transverse section across endozone showing smaller, newly formed zooecia having 3 to 4 sides distributed between larger, older, more polygonal zooecia, Hypotype USNM 432769 [NL IV 51(86)A-17L-A], X40. 2b. Longitudinal section showing a relatively narrow exozone. Otherwise similar to Figures 1b and lc, Hypotype USNM 432769 [NL IV 51(86)A-17L-A], 33. 2c. Tangential section with elongate zooecial cavity outlines due to slightly oblique nature of some zooecia. Otherwise similar to Figure la, Hypotype USNM 432769 [NL IV 51(86)A-17L-A], X33. . Oblique section through endozone showing regular budding pattern of autozooecia. Note smaller (relatively younger) zooecia with 3 to 4 sides, and larger (relatively older) more multisided zooecia whose planar walls smoothen out zooecially outwards to form subrounded apertures, Hypotype USNM 432813 [CB 130A-8-A], 25. . Oblique section through endozone as for Figure 3, Hypotype USNM 432785 [NL IV 94(129)A-3L-B], X25. 113 114 Figure BULLETIN 353 EXPLANATION OF PLATE 21 12 farphophragma‘yampla’ (Ulrich)! eo. 5.5 fee 5 Bin etet ee esi rete tee eee chia) eels 2) oven cle hel fer erent onan ogee an oe ete ent a oe la. Transverse section of endozone showing smaller, ontogenetically younger zooecia with 3 to 4 sides distributed between larger, older, more multisided zooecia whose planar walls have taken on a subrounded appearance, Hypotype USNM 432822 [NL IV 43(78)B-3L-G], 40. . Tangential section showing subpolygonal to subrounded autozooecial cavity outlines and increased numbers of angular meso- zooecia compared to 7. multitabulata, Hypotype USNM 432822 [NL IV 43(78)B-3L-G], X25. . Longitudinal section of exozone showing thin walls whose ordinarily laminar microstructure is obscure (cf. Figure 2b), Hypotype USNM 432822 [NL IV 43(78)B-3L-G], 100. . Longitudinal section showing a narrow exozone with thin walls, diaphragms throughout autozooecia thicker and more variably oriented in the exozone, and small exozonal mesozooecia. Note similarity to 7. multitabulata (cf. Plate 20, Figure Ic) but for absence of thick exozone, Hypotype USNM 432822 [NL IV 43(78)B-3L-G], x25. . Tangential section showing generally subpolygonal autozooecial cavity outlines and more common mesozooecia than for T. multitabulata due to less crowding peripherally by autozooecia, Hypotype USNM 432825 [NL IV 49(84)A-7R-B], x45. . Transverse section as for Figure la, Hypotype USNM 432825 [NL IV 49(84)A-7R-B], x40. 2c. Longitudinal section of exozone showing V-shaped laminae composing autozooecial walls, Hypotype USNM 432825 [NL IV 49(84)A-7R-B], * 100. . Longitudinal section showing an exozone wider than for Figure 1d and approaching that of 7. multitabulata, Hypotype USNM 432825 [NL IV 49(84)A-7R-B], X25. PLATE 21 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 112 wig 4 walt BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 112 PLATE 22 Figure MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH EXPLANATION OF PLATE 22 LUO MLO OMA PULCRELIC (UW 1TICh) are) 2, <.e. Wes = 5) Phe 2.2 Bees egeveb aye toa eeeh ete) lease 5 Gis clea Ghee etgoerangus iavebe aon Buelatchae Sie cueteaene es la. to 3 Longitudinal section showing very few diaphragms, restricted to proximal-most ends of zooecia in endozone and sometimes exozone, and fairly common mesozooecia in exozone with closely spaced diaphragms, Hypotype USNM 432895 [CB 149A-7- A], X25. . Tangential section showing rounded zooecial cavity outlines and subrounded to subpolygonal mesozooecial cavity outlines in fairly thick-walled portions of colony. Zooecia are more angular and walls thinner in a slightly deeper tangential cut in lower right corner of figure, Hypotype USNM 432895 [CB 149A-7-A], 45. Longitudinal section of exozone showing wall microstructure of distinct V-shaped laminae, Hypotype USNM 432895 [CB 149A-7-A], 100. . Tangential section of a thin-walled specimen showing round to subround autozooecial cavity outlines and polygonal meso- zooecial cavity outlines, Hypotype USNM 432894 [CB 72C-4L-C], x45. Transverse section of endozone showing polygonal zooecial cavity outlines, Hypotype USNM 432841 [NL IV 108(143)A-8- E}, X40. Si, TAPROOT BY DORT YEA RI GE BIG G Bicuerg Stor ORION IG cic. CMO DELS ORC cn Ona Bi cae rec EOE EL IO ee OMI OIM AAS eee cls oe Cs chm 4a. 4b. 4c. Longitudinal section of outer exozone showing V-shaped laminar wall microstructure, Holotype USNM 432920 [NL IV 108(143)A-3-E], x 100. Transverse section of endozone showing polygonal zooecial cavity outlines, Holotype USNM 432920 [NL IV 108(143)A-3-E], «40. Tangential section showing relatively thick walls, rounded (to subrounded) autozooecial cavity outlines, polygonal zooecia boundaries (appear as white lines), a macula in the upper right corner of figure, and few mesozooecia. The latter appear to have been crowded out peripherally by autozooecia, Holotype USNM 432920 [NL IV 108(143)A-3-E], x45. . Longitudinal section showing thicker walls and increased numbers of diaphragms in exozone than found in P. pulchella. Endozonal diaphragms are restricted to proximal ends of zooecial tubes, mesozooecia present in exozone, Holotype USNM 432920 [NL IV 108(143)A-3-E], 25. 115 Page 84 116 BULLETIN 353 EXPLANATION OF PLATE 23 Figure lee Rarvonalloporaigr anda M:ssp-VareiiflQia i) VAL ae eee penne tees tet eVes ediale = eos fats ie anole r= eae ete eae ne ee la. Longitudinal section showing wide exozone, increased numbers of diaphragms, and thicker exozonal walls compared to non- varietal form of the species. Note mesozooecia crowded out peripherally, Hypotype USNM 432962 [NL IV 108(143)A-15-C], X25. 1b. Longitudinal section of exozone showing wall microstructure of V-shaped laminae. Note median line within wall, Hypotype USNM 432962 [NL IV 108(143)A-15-C], «100. lc. Tangential section showing very thick walls, rounded (to subrounded) autozooecial cavity outlines, and megazooecia in macula in left center of figure. Note that nearly all mesozooecia present in lower exozone (see Figure la) are absent in tangential section (except for macular region), Hypotype USNM 432962 [NL IV 108(143)A-15-C], x45. ld. Transverse section of endozone showing polygonal zooecial cavity outlines, Hypotype USNM 432962 [NL IV 108(143)A-15- C], X40. » Hemiphragma ottawaensis: (ROOT)! s,s 6 ce wis esi tees he cue unio enane) © ees je hesaties @) = Rue ceeneiie) Waltons We ooteie Paton Tan eek ee 2a,2b. Longitudinal sections showing unevenly thickened laminar walls in both endozone and exozone, and diaphragms and hemi- phragms throughout oriented perpendicular to zooecial walls, Hypotype USNM 433073 [CB S0A-3-X], 25. 2c,2d. Tangential sections showing mainly subrounded zooecial cavity outlines, and numerous acanthostyles mainly at zooecial corners, Hypotype USNM 433073 [CB S50A-3-X], X33. 2e. Longitudinal section of exozone showing distinct broadly arched wall laminae, and hemiphragms, Hypotype USNM 433073 [CB 50A-3-X], 100. ty 89 PLATE 23 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 112 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 112 PLATE 24 Figure Lat. AVAERIORT TL @ (CATIA OS 1s, SU 319 G'S. ce1e OtdwO Ocho Biheod Gham IGT chon.© ouougi nor Og) CL old Ero etalon ID coach ic. aacliceti'd. blinuqsbep-o10-o-Sra.etauc la. MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH EXPLANATION FOR PLATE 24 Longitudinal section showing irregularly thickened and thinned autozooecial walls in exozone composed of V-shaped laminae, zooecial boundaries delineated by a dark line, even to crenulate autozooecial walls in endozone, and rare exozonal diaphragms, Holotype USNM 433017 [HCM 18(57)B-5-E], *25. . Tangential section showing rounded to subrounded zooecial cavity outlines, well-defined polygonal zooecial boundaries, un- common small mesozooecia, minute acanthostyle-like features, and a macula in right side of figure, Holotype USNM 433017 (HCM 18(57)B-5-E], 45. . Transverse section showing polygonal zooecial cavity outlines in endozone, Holotype USNM 433017 [HCM 18(57)B-5-E], x40. . Longitudinal section of exozone showing irregularly thickened and thinned walls with distinct V-shaped laminae whose apices are joined by an even dark line, Holotype USNM 433017 [HCM 18(57)B-5-E], 100. . Longitudinal section as for Figure 1d, Paratype USNM 433058 [CB 67A-3-A], 100. . Tangential section as for Figure 1b but for somewhat more common mesozooecia, Paratype USNM 433058 [CB 67A-3-A], x45. . Longitudinal section showing pinching and swelling of autozooecial walls in exozone, a dark median line marking zooecial boundaries within laminar walls, diaphragms absent, zooecial bends at both base of exozone and outer endozone, and several narrow mesozooecia, Paratype USNM 433058 [CB 67A-3-A], X25. | RATA OT AVERT S VECO) ococcqocmodsaeorvboc Ob benonoonoonpooooonoDonc Oooo Ono Ooo EO OES OOO 3. Longitudinal section of exozone showing distinct broadly arched wall laminae, and hemiphragms, Hypotype USNM 433073 [CB 50A-3-X], * 100. 117 89 INDEX AGantholaminatus Mao Clee nsecictyaeci esses nies eet eee eee esi 42 Acantholaminatus multistylus n. gen., NSP. ...... 6222 2ee eee eee eee eee BE EEE eee tee Hose nascaaeccae aie Dis 20, 42-44 96i(P 1 A) Acantholaminatusitypicusin. GED:, NSP: jails = ele2)a)se ee \-l=\aisleler= ls Massing se neece ate 18-22, 25-28, 42, 43, 96 (Pl. 3), 96 (PI. 4) AXcanthoporer (De imition) Memrete ter islore laters sisiovelars eletelosesaicveleistsletrietatclererate 30 Acanthostyler (Definition) ererclaceictecicie cle cteisiierclelelats scle ocisaciertaisreleelaiole 30 COATUENA, (CHMODIAIOD cocnacsoonncnacobdsoondagneanosddobeAonsneanene siggeeae siewinestines L6=19% 21) 24,25, 28,) 75, 77, 785) Wi (els 18) CATAL) ILGMO DY AG? “aqcacbogoonsencuaBqansaqdoacobeasonKnGcce* 24, 77 GCALLIS A GLAAOPOTAM weraeicteorsciaeieacinine sino ete sieeis elaisinisiersIelel-eie site sectetene 65 Ged Lis ET IdOtrYy DAs ejecta wae siete niet ieielale siste el -iote wiove sisie store sierra 19, 64-66 Amalgamate Wall Structure (Definition) .......................22. 30 Gilles, (CHIONORE, sodsosanaconontensobanaaneosooncenereasocer 24, 80, 81 CUDA, MATA LOONIE. Gapongdecedonndann qusanancareannonaadesnooadaccs mrstateteisielejefsieiele eee stosjaiais 13-17, 19-21, 23-29, 80-82, 114 (Pl. 21) AnaphragmanWirichyandiB asslety reeset ele sieeeiceisieeisicetle 87 ANAphY Ae Maiermulagenrsisi NaS cis ccceeeeeaisel oe secede eeciee sete Rete cesta iiisensa 13=17, 19-21; 23-29; 87, 88, 117 (Pl 24) Anaphragma mirabile Ulrich and Bassler ...................00000+ 87 angularis, Mesotrypa ... 13-17, 20-23, 25-29, 35-38, 94 (Pl. 1) angularis var. parvatrypa, Mesotrypa ........+++00eeeere eee e eee eee 38 GDP ESSA ELELETOLTY PA) eisjaisateeicietsloiaiaialeisislsisiaisiaisiavalelolals sepsieiotcls sels eeors 68 GNCUQLUIS BALL COPOY. Gi ix srreieieein = eee clalmieteelsmiemel-iseeeelsiomeioe iemeeioce 18 AstogeneticiGhan gel (DE finitlOM) Mereletectetstetelets series cele ietsctoteleteteleetet= 30 Atactoporarsubramosa WIniGh) a eessecrass esis esis ssleees see 68 Alactoporel lan Wirt Chi errcste cacti -leciseisieteie asi sisisleeisiel esis elelsisieisinielsi sarees 42 Autozooecion\ (Definition) iasqe-.seeee ase eee aes seec aeeeee cee see 30 Axialubiaphragms) (Definition) e--s-.eser seer aerens se csce see 30 AxialpResionn(Mennition) wermsse. ete esses nasser hese eeeeee 30 Balticopora arcuatilis Karklins ..... Batostoma ottawaense Foord ...... Batostomella Ulrich .............0005 Batostomella subgracilis (Ulrich) Hat aiclentneiesinessicte 13-19, 22-29, 57, 59, 61-63, 71, 104 (Pl. 11) Batostomella subgracilis (Ulrich) var. robusta n. var. ............+- Serpe asset ese 25, 28, 63, 64, 86, 104 (Pl. 11), 105 (Pl. 12) Bellevuewtamestoneecas se. -neees cee ae secet sash sicl- ese cnee tee teiseins Biostratigraphic Utility of Bryozoa Black@RiverssOrma toner. seer ereaceseeeeractsereceeeet esc BlackgRiveriStapere.cacsscemscteasces Blackriveranl StaGe sos tessa ccistec state cetriane teeter eeRen ee Blue Clay Shale Member of Hermitage Formation ................ 9 Brannon Member of Lexington Limestone ....................... 15 Bromide Formation: censcacecce ce sceeceeeccnacece osiacceermseciieceC 24 Bryozoan Assemblages and Relation to Lithotype, Macrofossils, and Environment of Deposition ena. -n seer ces scce nee ceesee: 23 Bryozoan Assemblage One ................... 13-19, 22, 23, 28, 29 Bryozoan Assemblage Two ................-+. 13-18, 22, 23, 28, 29 Bryozoan Assemblage Three ................. 13-19, 22, 23, 28, 29 Bythopora Mulleriand Dyer sa. .ncicceicceiesceeiissss «laces ecbeeieeets 57 Bythopora dendrina (James) ...._ 13-18, 20-29, 57—60, 103 (Pl. 10) Bythopora fruiticosa Miller and Dyer .............--.20+.e00ee00+ =i) Bythoporarsubgracilts Bassletiersercasseee senses se eee eee OL Eallopora Mall, snncecoaasntecsae sw Gace foesiewsemenessas pean seers 83 GalloporaxamplawMlnichiperceseccseccereccnonene ce sete 24, 80, 81 Gallopora\multitabulata (Wlrich)) 2.2... -ce2 25s «500s eeee 24, 80, 81 GalloporaypulchellanUlrichigees.ne-eeeee ee eeneeneseeetenere 24, 82, 84 Callopora pulchella var. persimilis Ulrich ................00+0000+ 82 CalloSGHOMOINYPA secs secreecere 24, 25, 28, 52-54, 101 (PI. 8) Galoporaselezantulaiialll Wraceencete teeter reece ences 82 Cannon Formation (= Cannon Limestone) ... 7, 11, 12, 17, 22, 56 Carters Formation (= Carters Limestone) ....... (CH PG tsy Wl WAS tke Catheys! Formation.c 02s secetntececeloas canoer eee cheer eneeeeres 7 CentraliB asing (lennessee) menace ect ees Oe Ul, 7/5 FAM GChaetetesidecipienssRomiIn Setae cases nee eter 39 Ghaetetesigracilis Nicholson) seccesnscea-neescenecceeeeeeceeeeeater 61 @hambexlaingBranch} Section tyeesece-eereseeete dace eter eeeer eerie Suey esaiciotte leiatsfertstote weletelas 7, 8, 10-14, 17, 18, 22, 24-26, 29, 81 ChamplainianiSeniesi..--ceceeesaeese eee eee ease eee eee eee: il, SY Sw7/ Characteristic Faunal Members (Biostratigraphic) ............... 24 ChickamaulgalGroup) cr scsc ee oecee sees cee see rete c eer ce eres 6, 28 Ghickamaugatlimestone) -feeeaceeaceeeeeeeeetereeeeseeeeeeee etre 5,6 @hickamauga Supersroupy cea. mcceeee sec eeeey ee eeeeeeeeh eee 11 Cincinnatian§stageterrr cesta eee eee eee eeec ee 21, 24, 46 Gladopora aedilissEichwaldWen--jecnser eeecee eee eee eee eee 65 Clays) BemysFormati ony: sissies ctiesseticee strictest 6, 15 Cobourg Formation 2. cocce creed sceeaece ete eeeeeeeceeeceeeers 21 CONMLCGS (StLQIMAlellarajnrecmriiciecccritteereeterec rere cee 78 Gonedont:Zone’8 (Midcontinent) ie. see aaeeeeeeeeece eee 11 Gonstellaria Dania), si csississas cases = seco ecieces see eeaces ee eee setae 21 Constellaria teres Hayes and Ulrich (Cystoporata) .............. 1S crenulatay Stigmatella s. s-csccennen ence adeeeree eee UY Grenulate \Walls/(Definition))ece-peeeeeeseetensee eee eseeee eee 30 Ctenodonta Member of Hermitage Formation .....................- 9 Curdsville Member of Lexington Limestone ............. O), MSY 17 CUIVAIG; HHOMOLTY PA rine) taste iene acl seie aecels eee tesserae 44 GyphotrypaUlrichvandtBassleteraceeses peste eee eeee eee Ui @yphotrypalacervulosa (Winch) eaneeeseceedeaeee eee ohaageodsuarprcnc 16-19, 21, 24, 25, 28, 75, 77, 78, 111 (PI. 18) Cyphotrypa switzeriensis Karklins ............22000.+eeeeeeseeeeeee 18 Gystiphragmiy (Definition) ee -paceescce cece er eee cece ree cee 30 Cystose (Cystoidal) Diaphragm (Definition) ...................... 30 Dalmanella Coquina Member of Hermitage Formation ...... ), i Dalmanella fertilis (Brachiopoda) ..................+--- 9, 11-14, 23 decipiens, Chaetetes Decorah Formation Decorah Shales .......... Deicke Bentonite ........ DekayellasMlnich) Wiesscstase deecsseecim et decease eecceee ee eee eee DekayellaypraenuntiaWnich) seccss-ceccace cece eee eeenee errr 1) Dekayella praenuntia var. echinata Ulrich .......... 19, 22, 24, 75 Dekayella praenuntia var. simplex Ulrich ..............-- 24, 74, 75 Dekayella praenuntia var. multipora Ulrich ...............-...+++ 75 Dekayellarrobustashoordteeceeenceceo acheter eee erect 69 Dekayiayprolificai (Ulrich) wee ememeseeoca eee erect eeeeeeeeee 68 Dekayiaysubramosal(Wlrich) ieescesee cesses eects 68 Dekayiavulrichi (Nicholson) eec-rereacnceertecaceerae see eeeeeeeee 69 dendrina, Bythopora ........... 13-18, 20-29, 57—60, 103 (PI. 10) dendrina Helopora me acces eee ee nee eee eee LO Diaphragms (Definition) | eect aeceee aecleete sels eeeeee sees 30 Diaphragm-Wall Unit (Definition) ......................00esee neon 31 Dinorthis pectinella (Brachiopoda) ....................0.506055 135,23 Diplotryparinfida lr Ghia scitet-eietsaiscesee seem Ce ences eee 5 ee! DistaliDirectiont (Definition) iaseesereseee eee eeeeseerereee teres 31 GIStINGIASpINOSA Sti SMatellantaeeera cee eee eee rere padochcaceeeroanar aces 13-15, 18-21, ClegantulaNCaloporaesrcccn secre eee er ene ee eee ee eee cee Encrusting Colony (Definition) ..................... Endacanthopore) (Definition) | reece celerieeiesereiee ceeistercre eee MIDDLE ORDOVICIAN BRYOZOA OF TENNESSEE: MARINTSCH 119 Bndacanthostyle (DEMON) eam