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CONTENTS /NUOGTIEYSI Soe cole OHO ae EO IouIod Core aoc icici pO OIC rrae 5 |rax travail ioy Vie eerererers occ nemnS ere in eae eS SIMIC nner 5 Bibbreviations) of REPOSItOMeSi yn ees ciel cielererersie ie etter ieke 6 PNCKMOMW LEAR MENS i «yeseyeyerevcrersicuntsisyas See cere: o\e, slsioxere /eisyersveseie ctsroteve oe 6 Latest Ordovician Paleogeography, Lithofacies, and Solitary Rugose Corals of Eastern North America Own TOVWeo todo coeUCUOP rca a emoe comaarccoctcrace 8 Richmond Group Iino NCiTOiy hidosaeboee oo Souenymance Shanes doses 8 Cincinnati Arch region Sati Sap Dy) wre sv eyeseccte s,cuc tego) suse axe aro orcas yey suave sucyeperseces 9 Depositionalienvironmentseeeee sass eee erases 11 G@incimnativATChs sercip eect iieeiosren see iee 12 Solitary rugose corals Grewingkia canadensis (Billings, 1862) Stratigraphic distribution .................... 13 OnientationvoficoralSisee eee eee eee 13 (COTA ESI ZS ara dec csiereysisyese a: mists reve ROR HARE 14 EPIZOANS Be eer-o chee amie ecco aerate ese ers y artery 17 BOUIN ES eres hetero aaagern tears Ae ene cst acres eae pe 17 Intraspeciiicavallationieeceeerenrrrececrrice 19 Streptelasma divaricans (Nicholson, 1875b) Stratigraphic distribution =. ---.4.s2--c-s-6-6- 22 Onentationioficoralsieeee eee seeee eee cee eS Gorallfsize sy. Aa tacreageic ears sisvecns cis iecesonete colcese a setae oc ES PIZOANIS ery sae eters csegake sere fone y TON oe eros aes eee 25 BOVINE Ske sovaneccsey nets vcs tonel oyetetereicne tere reve winreee eretereiene Intraspecificavanationa. -praeesseiseciciies 22> SUM ALY pererentoycyystaeiete tetera os Nee iis AOE 26 BurkesvillesikKentuckyansereeeeaemeercec eens 27 Goodlettsville-Gallatin area, Tennessee ............. 27 ittle!Sturgeon|Bay, Wisconsin! 2... 2.66.2 - 244s 29 ittlesBayadesNoc Michiganiee = a.cesceeer cri ences 29 Drummond Island, Michigan ...................---- 30 Manitoulin Island, Ontario....................+.... 32 Meaford Ontati Omer syracuse cea ce irae ae Oke 33 StreetsvillenOntanlopereiecrascicciiieistlteisircr ier eisieetetr: 34 Montreal Que be Cie risrtetcecpe ci oyaseasie eros cis yee 34 akesStaJobns @Nebec anes renee ree ens 34 Maquoketa Group lintanoyslifaske SocoeBue cate ome tee on toe ee cemetooen ae) INOMUCERIG gt ON Aidesan ap dee aa Momma 6 cue eee obs moe 35 Southeastern Iowa and northwestern Illinois........... 36 Mhe bes willinoissens sis ctor ete ioleestave.c eesti iste cieihe etaeterees 36 Uppermost Ordovician of Oklahoma, Missouri and Illinois Ifotiroxalttolttoy tamtmectnte caiae seo eee eouUn eas poste cur 36 ArbucklesMountainss Oklahomaleneaacscerstiaee serine 39 Cape! GirardeaulCounty, Missount esse eee eee eee 39 RikeyGounty-sMissOulIEe ee eee eee ree Eee Eee 40 WilliGounty Dinos, «ccume: cmos met Go aati ereG 40 Continental margin Introductions ces: soy stsaskexetce uan-ke, eee CEE 40 RenobscotiCountys) Maineseenaeracereriine eeeeriaee 41 Ashland Maine: oi ca cram ccreystervercesnispeserocre armen 41 Perce: (QUE DE Gri aie cyae cece ne Maer rae 41 Anticosti Island, Québec Stratioraphy: 2 y. sevetecas.ci cst «cuss eerste ee oer 42 SO Main TUBOSO GCOBIS soonceccononpecdoocndsussunce 45 Paleobiogeography of Latest Ordovician Solitary Rugose Corals in Eastern North America COM OUCN ueman aethroeeta meno d s ce heemeode aed oot eden font or 47 Red River-Stony Mountain Province Tt Gui th Maes tics yeveness tones eysysncgehers opaiav =) sususee foie Romeo eae ee 48 MaquoketalSubprovince errr rant ere reise ener 48 Maritime Subprovince rear aese cere eee eee renee 48 Richmond Province INtnOGUCHON 2:2, s/esze5nr eerste ae ibire ae TE ia eae Oana 49 Oli TG O ces ae Ocoee See Toe Eo oon eeee oda 50 Subsequent Mistry, asec eee cee eee GREE 51 EdgewoodlProvince serene een eee ec careertce eee 51 Systematic Paleontology Introductt Omi. /y5srDY\¥Y JUN 4 1982 2 siviVERSITY Latest Ordovician Solitary Rugose Corals of Eastern North America by Robert J. Elias anniversary year PALEONTOLOGICAL RESEARCH INSTITUTION Officers PRESIDENT: ao ecscie ware ohs ore oct ak etared hel MET reG rote cece bats Sener JOHN POJETA, JR. VICE-PRESIDENT cps see yee tard he ssn ee eer UAE ROSA aol one Bruce M. BELL SECRETARY areca cio eee SE on ie Ear: PHiLip C. WAKELEY AGING (DREASURERG em eine cctroen ei ceo eee on RoBERT E. TERWILLEGAR ASSISTANTS GUREASURE Rewacteiis tar oie ee Chen Ieee JOHN L. CISNE DIRECTO RG cso eey cr MO CaP ECE ee eer PETER R. HOOVER DIRECTORS EMERIDUS I: cisraccmiciestevavere tere tarsi mene eds KATHERINE V. W. PALMER LEGATIX COUNSEDR) oi id. cca rete ees eee ORT ARTE FRM noise Pore ARMAND L. ADAMS Trustees Bruce M. BELL (to 6/30/84) DUANE O. LERoy (to 6/30/84) RICHARD E. ByRbD (to 6/30/83) WILLIAM A. OLIVER, JR. (to 6/30/83) KENNETH E. CASTER (to 6/30/82) KATHERINE V. W. PALMER (Life) JOHN L. CISNE (to 6/30/82) JOHN PoJETA, JR. (to 6/30/82) LEE B. GIBSON (to 6/30/83) RAYMOND VAN HoutrteE (to 6/30/82) REBECCA S. 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Hoover Director Paleontological Research Institution 1259 Trumansburg Road Ithaca, New York 14850 U.S.A. 607-273-6623 LATEST ORDOVICIAN SOLITARY RUGOSE CORALS OF EASTERN NORTH AMERICA By RoBErRT J. ELIAS Department of Earth Sciences University of Manitoba Winnipeg, Manitoba R3T 2N2, Canada ABSTRACT This study comprises comprehensive taxonomic, paleoecologic, biostratigraphic, and paleobiogeographic analyses of latest Ordovician (Richmondian and Gamachian; Ashgill) solitary rugose corals in eastern North America. The corals are assigned to three provinces distinguished on the basis of assemblages and characteristic species. The distribution of these provinces, as well as taxa within them, was determined by regional environmental parameters related to paleogeography. During Richmondian time, the Richmond Province occupied a narrow belt extending northward from the Nashville Dome of Tennessee, along the Cincinnati Arch region of Kentucky, Indiana, and Ohio to northern Michigan, and eastward through southern Ontario and Quebec. It coincided with a carbonate platform at the margin of an epicontinental sea that was receiving clastic sediments from the Queenston delta (Ontario, New York, Pennsylvania, and Ohio). Solitary coral diversity was low, but variability within several species was high. The following taxa were present: Streptelasma divaricans (Nicholson, 1875b), Grewingkia canadensis (Billings, 1862), G. deltensis n. sp., and G. rustica (Billings, 1858a). This province was isolated by the positive Canadian Shield, Taconic Mountains, and Nashville Dome, and by deeper water in which the Maquoketa Group shale of the upper Mississippi valley was deposited. Solitary corals in the Maquoketa Group and those at the eastern continental margin belonged to the Red River—-Stony Mountain Province, which included most of North America during the Late Ordovician. The vast continental interior portion was occupied by shallow, interconnected epicontinental seas, whereas normal open marine environments were present at the continental margins. The Maquoketa Subprovince was characterized by the paucity and very low diversity of solitary corals in carbonate beds within shales of the Maquoketa Group. The following taxa were present: Helicelasma randi Elias (1981) and Bighornia cf. B. patella (A. E. Wilson, 1926). The diverse assemblage associated with carbonate sequences in the Maritime Subprovince (Anticosti Island and the Gaspé Peninsula of Québec, and northern Maine) included typical continental interior species together with genera characteristic of North American continental margins and Baltoscandia. The following taxa were present: Strep- telasma rankini n. sp., S. affine (Billings, 1865), Helicelasma selectum (Billings, 1865), Deiracorallium angulatum (Billings, 1862), Grewingkia penobscotensis n. sp., G. pulchella (Billings, 1865), Grewingkia sp., Lobocorallium trilobatum vaurealense (Twenhofel, 1928), Kenophyllum? sp., Bodophyllum neumani n. sp., Bodophyllum? sp., B. englishheadense n. sp., Bighornia cf. B. patella (A. E. Wilson, 1926), and Paliphyllum ellisense (Twenhofel, 1928). At the end of Richmondian time, regression of the eastern North American epicontinental sea resulted in extinction of corals in the Richmond Province and Maquoketa Subprovince. The latest Ordovician (?Gamachian) Edgewood Province coincided with a carbonate sequence deposited in normal open marine environments during a transgression into the continental interior (upper Mississippi valley). The solitary corals resembled those previously restricted to continental margins, and foreshadowed the cosmopolitan Silurian fauna. The following taxa were present: Streptelasma leemonense n. sp., Streptelasma sp., S. sub- regulare (Savage, 1913), and Bodophyllum shorti n. sp. INTRODUCTION This study comprises comprehensive taxonomic, paleoecologic, biostratigraphic, and paleobiogeo- graphic analyses of latest Ordovician (Richmondian and Gamachian; Ashgill) solitary rugose corals in east- ern North America (Text-figs. 1, 2). Field work in Missouri, Tennessee, Kentucky, In- diana, Ohio, northern Michigan, and southern Ontario in the summers of 1977 and 1978 provided extensive collections as well as paleoecologic and stratigraphic data. To ensure stratigraphic control, all sections ex- amined have been described in the literature, or are near described sections (see *‘Appendix: Collecting Localities’). The lithology and megafossils were ob- served at each locality, and an extensive search for solitary corals was made. Where present, their exact stratigraphic position was recorded. Relative abun- dance was estimated qualitatively (rare, sparse, un- common, common, abundant), with rare meaning one to several corals were found and abundant meaning they were so prolific it was not feasible to collect all the specimens. When possible, orientation on bedding surfaces was noted. All corals seen were collected, except in the few stratigraphic intervals where they were abundant. Almost 1000 specimens were collected for this study. 6 BULLETIN 314 In the Cincinnati Arch region, 34 localities were ex- amined to prepare composite sections | to 14 (Text- fig. 3). Four localities near Burkesville, Kentucky, three in the Goodlettsville-Gallatin area of Tennessee, and three at Little Bay de Noc, Michigan, provided data for composite sections 15, 16, and 17, respec- tively (Text-figs. 3, 18). Stratigraphy at Drummond and Manitoulin Islands is shown in composite section 18/19 (Text-fig. 18). Three localities were studied on Drummond Island. Of 25 exposures seen on Manitou- lin Island, six have important intervals that contain solitary corals. In eastern Missouri, sections 20a and 20b in Cape Girardeau County and sections 2la and 21b in Pike County were examined (Text-fig. 21). Approximately 1000 corals from many of the above areas and from collections made elsewhere in eastern North America were obtained on loan. Most speci- mens from the Cincinnati Arch region, Michigan, On- tario, and southwestern Québec were collected by A. F. Foerste. W. H. Twenhofel’s extensive collection was the major source of material from Anticosti Is- land, Québec. Solitary corals from Maine were col- lected by R. B. Neuman (U.S. Geological Survey, Washington, D.C., U.S.A.). Morphologic and descriptive terminology used herein for solitary Rugosa follows Hill (1935, 1956) and Elias (1981). To examine internal morphology, most corals were sectioned transversely in several places, and relatively few were sectioned longitudinally. Thin sections of more than 300 specimens have been pre- pared. Biometric and other data recorded during this study were presented in Elias (1979). ABBREVIATIONS OF REPOSITORIES FMNH UC. Field Museum of Natural History, Uni- versity of Chicago, Chicago, Illinois, U.S.A. GSC Geological Survey of Canada, Ottawa, Ontario, Canada ROM Royal Ontario Museum, Toronto, On- tario, Canada SIU Southern Illinois University, Carbon- dale, Illinois, U.S.A. SUI State University of Iowa, Iowa City, Iowa, U.S.A. UCGM University of Cincinnati Geological Mu- seum, Cincinnati, Ohio, U.S.A. UI University of Illinois at Urbana-Cham- paign, Urbana, Illinois, U.S.A. University of Michigan Museum of Pa- leontology, Ann Arbor, Michigan, WESEAr UMMP USNM National Museum of Natural History, Smithsonian Institution, Washington, DiGe UW ESPAG YPM Peabody Museum, Yale University, New Haven, Connecticut, U.S.A. ACKNOWLEDGMENTS I extend my sincere thanks to Kenneth E. Caster (major advisor), David L. Meyer, and Paul Edwin Pot- ter of the University of Cincinnati, who supervised the doctoral dissertation from which this publication was adapted. I am grateful to the following for providing infor- mation on stratigraphic sections in the areas indicated: Kentucky—R. C. Kepferle, R. Q. Lewis, Sr., W. L. Peterson, and W C Swadley (U.S. Geological Survey, Kentucky, U.S.A.); Wisconsin—P. E. Allen (Univer- sity of Wisconsin at Green Bay, Green Bay, Wiscon- sin, U.S.A.); Manitoulin Island, Ontario—P. Copper (Laurentian University, Sudbury, Ontario, Canada); Illinois—T. Guensburg (University of Illinois at Ur- bana-Champaign, Urbana, Illinois, U.S.A.); Mis- souri—l. R. Satterfield (Missouri Geological Survey, Rolla, Missouri, U.S.A.), P. M. Sheehan (Milwaukee Public Museum, Milwaukee, Wisconsin, U.S.A.); Maine—R. B. Neuman (U.S. Geological Survey, Washington, D.C., U.S.A.); Percé, Québec, and Scandinavia—P. J. Lespérance (Université de Mon- tréal, Montréal, Québec, Canada); Anticosti Island, Québec—T. E. Bolton (Geological Survey of Canada, Ottawa, Ontario, Canada). Loans of specimens were arranged by the following: M. H. Nitecki (FMNH UC), T. E. Bolton (GSC), P. Copper (Laurentian University, Sudbury, Ontario, Canada), J. Waddington (ROM), T. Guensburg (SIU), H. L. Strimple (SUI), D. B. Blake (UI), R. V. Kesling NORTH AMERICA| EUROPE Gamachian Stage Hirnantian Stage Maysvillian Stage Edenian Stage Text-figure 1.—Time-stratigraphic subdivisions of the Upper Or- dovician for North America (Twenhofel ef al., 1954; Sweet and Bergstr6m, 1971) and Europe (Ingham and Wright, 1970), including informal subdivisions of the Richmondian (see Kohut and Sweet, 1968, pp. 1456, 1457, fig. 2). Caradoc Series ” o 5 1 | Zl o 5 Chor Rawtheyan Stage Y1s| “Whitewater” a.) s eis “Liberty” Cautleyan Stage z ae “Waynesville” = 4 Pusgillian Stage £|& “Arnheim” St = io) £ Oo ORDOVICIAN RUGOSE CORALS: ELIAS 7 LEGEND Graywacke, quartzite, conglomerate, slate, volcanic rocks Carbonate rocks with shale and mudstone Juniata Fm. Nashville Dome | oS Ze Maquoketa Gp. A Uppermost Ordovician carbonate rocks Polk Creek Fm. Af Thrust fault te) km __ 300 Es Ax® Solitary rugose corals Text-figure 2.—Latest Ordovician paleogeography and lithofacies in eastern North America. Solitary rugose corals are known from expo- sures in the numbered areas. 1. Cincinnati Arch region, Ohio, Indiana, and Kentucky 12. Northeastern lowa 2. Burkesville, Kentucky 13. Southeastern Iowa and northwestern Illinois 3. Goodlettsville-Gallatin area, Tennessee 14. Thebes, Illinois 4. Little Sturgeon Bay, Wisconsin 15. Arbuckle Mountains, Oklahoma 5. Little Bay de Noc, Michigan 16. Cape Girardeau County, Missouri 6. Drummond Island, Michigan 17. Pike County, Missouri 7. Manitoulin Island, Ontario 18. Will County, Illinois 8. Meaford, Ontario 19. Penobscot County, Maine 9. Streetsville, Ontario 20. Ashland, Maine 10. Montreal, Québec 21. Perce, Quebec 11. Lake St. John, Québec 22. Anticosti Island, Quebec 8 BULLETIN 314 (UMMP), W. A. Oliver, Jr., and R. B. Neuman (U.S. Geological Survey, Washington, D.C., U.S.A.), F. J. Collier (USNM), J. S. Lawless (YPM). I thank Per- Erik Litz (University of Cincinnati) for preparation of thin sections. W. A. Oliver, Jr., in cooperation with F. J. Collier, supervised sectioning of most USNM specimens. The following reviewers offered valuable criticisms and suggestions: Richard S. Laub (Buffalo Museum of Science, Buffalo, New York, U.S.A.), Bjorn Neuman (University of Bergen, Bergen, Norway), and William A. Oliver, Jr. (U.S. Geological Survey, Washington, D.C., U.S.A.). The editorial work of Peter R. Hoover (Paleontological Research Institution, Ithaca, New York, U.S.A.) is greatly appreciated. Field work for this project was supported by: Geo- logical Society of America, Research Grant (1977); Sigma Xi, Grant-in-Aid of Research (1977); U.S. Na- tional Academy of Sciences, Bache Fund Grant (1977); University of Cincinnati, Summer Research Fellowships (1977, 1978); University of Cincinnati, Department of Geology, Travel and Research Funds (1977, 1978). Publication of this study was made pos- sible by grants from: Natural Sciences and Engineer- ing Research Council of Canada (1980, 1981); Univer- sity of Cincinnati, Department of Geology (1981); University of Manitoba, Research Board (1981). LATEST ORDOVICIAN PALEOGEOGRAPHY, LITHOFACIES, AND SOLITARY RUGOSE CORALS OF EASTERN NORTH AMERICA OVERVIEW The Late Ordovician Taconic Mountains along the eastern continental margin of North America were the source of a Richmondian clastic wedge deposited on the craton (R. B. Neuman, 1976; Dennison, 1976; Text-fig. 2). Nearest the uplift, the Juniata Formation comprises continental channel and overbank sand- stones with some siltstones and shales. Distally, it consists of lower delta plain redbeds that grade into the grayish-red deltaic shales and siltstones of the Queenston Formation. The Sequatchie Formation and Richmond Group carbonate rocks and shales, and the Maquoketa Group shales were deposited in an epicon- tinental sea. The Richmond Group thins and the amount of dolomite and terrigenous sand in it in- creases southward along the Cincinnati Arch region, which was probably a platform, to the positive Nash- ville Dome. The amount of carbonate and terrigenous sand in the Maquoketa increases and thickness of the group decreases toward the Transcontinental and Wis- consin Arches and the Ozark Dome, which were slightly positive. In general, Richmondian sedimenta- tion in eastern North America was affected by positive structures rather than by well-defined subsiding ba- sins. The typically regressive stratigraphic sequences may reflect a eustatic sea-level drop accompanying Late Ordovician glaciation centered in Africa (Berry - and Boucot, 1973; Dennison, 1976). Following a period of post-Maquoketa erosion, a thin unit of uppermost Ordovician (?Gamachian) car- bonate rocks was deposited in the Arbuckle Moun- tains area of Oklahoma, in eastern Missouri and west- ern Illinois, and in northern Illinois. These strata represent the initial stage of a transgression that may be related to deglaciation. On the continental margin, a thick Late Ordovician sequence of carbonate rocks and shale was deposited at Anticosti Island, and a unit including carbonate rocks and mudstone formed on the Gaspé Peninsula. These carbonate rocks grade into very thick sequences of polymict conglomerates, graywackes, and siltstones in northern Maine. Conglomerates, graywackes, quartzites, slates, and volcanic rocks are present in Nova Scotia and Newfoundland (Poole et al., in Doug- las, 1970, fig. VI-12, pp. 257, 258). Black graptolitic shale of the Polk Creek Formation occurs in the Ouachita Mountains of Arkansas and Oklahoma. Latest Ordovician solitary rugose corals are found almost exclusively in carbonate rocks. They are most common in the Richmond Group, in carbonates of the continental margin, and in the uppermost Ordovician carbonate unit overlying the Maquoketa Group (Text- fig. 2). Solitary Rugosa are sparse in carbonate beds within the Maquoketa. They are associated with cal- careous debris in the clastic sequences of northern Maine. RICHMOND GROUP Introduction The Richmond Group forms a narrow carbonate belt that extends from the Nashville Dome in Tennessee along the Cincinnati Arch region of Kentucky, In- diana, and Ohio to northern Michigan and Manitoulin Island, Ontario (Text-fig. 2). It was deposited during Richmondian time at the margin of an epicontinental sea between the Queenston deltaic shales and Maquo- keta marine shales. In general, the group comprises a regressive sequence including characteristic interbed- ded carbonate rocks and shales, carbonate units, and beds of abundant colonial corals and stromatoporoids. A Richmond Group fauna occurs in carbonate beds at the top of the Maquoketa in the Green Bay, Wiscon- sin, area. In the vicinity of Meaford, Streetsville, and Montréal in southern Ontario and Québec, the Rich- ORDOVICIAN RUGOSE CORALS: ELIAS 9 mond lithology was overlapped by sediments of the prograding Queenston delta. An outlier including Richmond strata is present at Lake St. John, Québec. The lower and upper boundaries of the Richmond Group (Winchell and Ulrich, 1897) and Richmondian Stage (Foerste, 1903) as presently recognized are shown in Text-figures 3 and 18. Although the Rich- mond Group is seldom lithologically distinct from the underlying Edenian-Maysvillian sequence, the term is retained herein for reference to the belt of Rich- mondian strata having a depositional history and fauna similar to that of the type sections in the Cincinnati Arch region. Cincinnati Arch Region Stratigraphy Prior to 1960, stratigraphic subdivision of the Rich- mond Group in the Cincinnati Arch region (Text-fig. 2, area No. 1) was based on faunal zonation, and re- sulted in recognition of the Arnheim, Waynesville, Liberty, Whitewater, and Elkhorn Formations. The history of development of this classification was sum- marized by Weiss and Norman (1960). These divisions are now viewed as invalid rock-stratigraphic units, but have commonly been used in the sense of time-strati- graphic subdivisions of the Richmondian Stage (Kohut and Sweet, 1968, pp. 1456, 1457). They are used as such herein, and the names are placed in quotation marks to emphasize their informal nature (Text-fig. 1). Since publication of the Code of Stratigraphic No- menclature (American Commission on Stratigraphic Nomenclature, 1961), attempts have been made to subdivide the Cincinnatian sequence lithostratigraph- ically. In Indiana, this has been done by Fox (1962), Brown and Lineback (1966), and Gray (1972). Gray’s (1972, table 1) subdivision of the upper Cincinnatian into the Dillsboro Formation and Whitewater Forma- tion, including the Saluda Member, is followed herein. Richmondian strata on the northeastern side of the Cincinnati Arch region are lithologically similar to those in Indiana, and Gray’s classification is herein extended into Ohio. In Kentucky, the Richmond Group has been lithostratigraphically subdivided through the mapping program of the U.S. Geological Survey in cooperation with the Kentucky Geological Survey. These units have been described on U.S. Geological Survey Quadrangle Maps, and were dis- cussed by Weir, Greene, and Simmons (1965), Peck (1966), Simmons and Oliver (1967), and Peterson (1970). The Richmond Group of the Cincinnati Arch region is overlain by the middle Llandovery (Lower Silurian) Brassfield Formation. The contact is generally discon- formable, but a paraconformity exists in the eastern part of the region (Gray and Boucot, 1972, p. 1301). Southeast.—On the southeastern side of the Cincin- nati Arch region (Text-fig. 3, sections 6—9), the Ash- lock Formation, which is partly Maysvillian in age, is overlain by the Drakes Formation. The Terrill Mem- ber of the Ashlock Formation consists primarily of evenly-laminated, greenish gray, dolomitic mudstone. Ripple marks and mud cracks are common in some areas. Bryozoans and brachiopods are locally sparse at the base, and small stromatolites are occasionally found near the top of the member (Weir, Greene, and Simmons, 1965, p. 13). The unit is silty in the vicinity of sections 7 and 8, and the amount of mud increases to the north at section 9. The basal portion of the overlying Reba Member of the Ashlock Formation consists of gray, micritic limestone with sparse ostra- codes. Cylindrical burrows oriented perpendicular to bedding planes are abundant at southern localities. The upper portion is wavy-bedded, silty, medium- grained limestone that generally becomes argillaceous toward the top and contains abundant bryozoans and brachiopods (Weir, Greene, and Simmons, 1965, p. 113) The Rowland Member forms the lower part of the overlying Drakes Formation. It consists of laminated, greenish gray, dolomitic or limy, silty mudstone. The unit becomes less silty but increasingly dolomitic and argillaceous to the north. Some bedding surfaces have ripple marks or mud cracks. Megafossils are absent to rare (Weir, Greene, and Simmons, 1965, p. 17). The uppermost Richmondian unit is the Preachersville Member of the Drakes Formation. It is similar to the Rowland Member, but contains argillaceous dolomite and dolomitic limestone in resistant beds that are com- monly thicker near the base of the member and in- crease in abundance northward. Poorly preserved bryozoans and sparse brachiopods occur in some strata (Weir, Greene, and Simmons, 1965, p. 18). The Otter Creek coral bed is locally present at the base of the Preachersville Member in the vicinity of sections 6 and 7 (Simmons and Oliver, 1967). It is usually less than 1 m thick, and consists of gray, generally medi- um-grained, argillaceous limestone with abundant co- lonial corals of the genera Calapoecia, Foerstephyl- lum, and Tetradium. Also common are solitary corals, cylindrical stromatoporoids, and brachiopods. Southwest.—On the southwestern side of the Cin- cinnati Arch region (Text-fig. 3, sections 3, 4), the Grant Lake Limestone is overlain by the Drakes For- mation. The type Grant Lake on the eastern side of the Cincinnati Arch is Maysvillian in age (Peck, 1966, pp. 14, 16), but on the southwestern side it extends 10 BULLETIN 314 into the Richmondian. The unit consists of irregularly- bedded, silty and argillaceous, gray, fossiliferous lime- stone, and shale in discontinuous beds and partings. Thick intervals of cross-bedded calcarenite occur lo- cally. Brachiopods and bryozoans are abundant, es- pecially in the limestone. To the south, the portion of Grant Lake Limestone at the base of the Richmondian grades into the Gilbert Member of the Ashlock For- mation (Weir, Greene, and Simmons, 1965, p. 12). This member, in the vicinity of section 4, consists of evenly- to wavy-bedded, gray, fossiliferous limestone with gray shale partings and interbeds. It contains bra- chiopods and gastropods, with stromatoporoids near the top. The Rowland Member at the base of the Drakes Formation is similar to the Rowland Member on the southeastern side of the arch, but is more calcareous and fossiliferous. The overlying Bardstown Member consists of gray, silty and argillaceous limestone in discontinuous and lenticular beds, with sparse to abundant fossils and fossil fragments (Peterson, 1970). Brachiopods, bryozoans, solitary corals, and molluscs are common. The colonial corals Tetradium, Foerste- phyllum, Favistina, and Calapoecia form prominent biostromes. The Saluda Dolomite Member is present at the top of the Drakes Formation. At its base, the dolomite is thinly-bedded, calcitic, silty, and argilla- ceous. Above this, it appears massive in outcrop and is generally unfossiliferous. In the upper part, it is lo- cally finely-laminated and burrowed. At the top of the member, limestone or dolomite and shale are pre- served in some areas, and locally contain the colonial coral Tetradium, or ostracodes and gastropods. East.—On the eastern side of the Cincinnati Arch region (Text-fig. 3, sections 1, 10), the Richmond Group comprises the Bull Fork Formation and the overlying Drakes Formation. The Bull Fork consists of alternating shale and limestone. The gray shale con- tent increases from about 20 percent at the base to about 80 percent near the top of the unit. The generally fossiliferous limestone forms even to wavy and irreg- ular strata, some of which are ripple-marked. Beds of sparsely fossiliferous micritic limestone with locally common ostracodes increase in abundance southward, whereas evenly-bedded to cross-bedded calcarenite is more common northward. Brachiopods and bryozoans are the most abundant fossils, but corals, trilobites, molluscs, crinoids, and ostracodes are common local- ly. In the vicinity of section 1, a solitary coral bed is present near the middle of the formation (Peck, 1966, pp. 16-22). The Sunset Member is recognized at the base of the Bull Fork Formation in the vicinity of sec- tion 10. The member is predominantly argillaceous to silty limestone, with the remainder being gray shale. Brachiopods are sometimes found near the base, and stromatoporoids are locally present, especially near the top. Overlying the Bull Fork, the Drakes Formation comprises a northern extension of the upper part of the Preachersville Member. It consists of calcareous to dolomitic mudstone with minor sparsely fossilifer- ous dolomite and limestone interbeds and lenses. The mudstone is generally grayish green, but is locally red- dish purple near the top, as at locality Ic. West.—On the western side of the Cincinnati Arch region (Text-fig. 3, section 2), the Bull Fork Formation intertongues with the upper Grant Lake Limestone of the southwest. In the vicinity of section 2, the Rich- mond Group comprises the upper part of the Bull Fork Formation and the overlying Drakes Formation. Bull Fork strata here and at the type area on the eastern side of the arch are lithologically similar. The Rowland Member at the base of the Drakes Formation consists of argillaceous, micritic limestone in even to nodular beds up to | m thick, with mudstone interbeds. The member is not dolomitic, as it is to the south. Colonial corals are abundant in local biostromes, and brachio- pods and bryozoans are scattered in the unit. The Marble Hill bed of this area is included in the Rowland Member and comprises gastropodal and echinodermal calcarenite (Swadley, 1980). The overlying Bardstown Member consists of fossiliferous limestone in thin, even to irregular beds, with gray shale interbeds. Bra- chiopods and bryozoans are abundant, together with solitary corals, molluscs, crinoids, and trilobites. The proportion of shale is greater than that to the south. The Bardstown thickens immediately north of section 2 where the Rowland Member pinches out, and is in- distinguishable from the underlying Bull Fork For- mation. The overlying Saluda Dolomite Member of the Drakes Formation is the uppermost Richmondian unit in this area. In the basal portion, thin beds of argilla- ceous limestone containing brachiopods and bryozo- ans occur in argillaceous dolomite. The upper part of the member is generally unfossiliferous, thickly-bed- ded dolomite. A thin bed of fossiliferous limestone is rarely present at the top. Northwest.—On the northwestern side of the Cin- cinnati Arch region in Indiana (Text-fig. 3, sections 11, 5, 12), the Maysvillian to Richmondian Dillsboro For- mation is overlain by the upper Richmondian White- water Formation, which includes the Saluda Member. The Dillsboro Formation (equivalent to the Tanners Creek Formation of Fox, 1962, pp. 626-628) compris- es thin beds of argillaceous limestone alternating with calcareous shale. Fossils are common to abundant, ORDOVICIAN RUGOSE CORALS: ELIAS 11 and include bryozoans, brachiopods, and trilobites. Solitary corals are common in the upper Dillsboro at southern localities such as section 11 and the Clifty Power Plant section of Hattin et al. (1961, pp. 328-331). Limestone beds are much more fossiliferous than the shales. The biostratigraphy was discussed by Fox (1962). Faunal distribution and abundance has been shown for interval Sa (Hay, 1977, fig. I-10) and intervals 5b-6 to 9 (Hay, 1977, fig. I-8, Liberty For- mation) of section 5. The overlying Whitewater Formation is composed predominantly of a variety of thin and often rubbly- bedded argillaceous limestones, with some shale and dolomite (Fox, 1962, p. 628; Brown and Lineback, 1966, p. 1022). Shale intervals occur toward the top of the formation at northern localities. Fossils, especially bryozoans, brachiopods, solitary corals, and molluscs, are abundant in the lower Whitewater Formation in the north. Faunal distribution and abundance has been shown for intervals 12a-1 to 9 of section 12 (Hay, 1977, fig. I-6) and intervals 5b-1 to 5 of section 5 (Hay, 1977, fig. I-8). The upper Whitewater is unfossiliferous to sparsely fossiliferous. Biostratigraphy of the formation was discussed by Fox (1962). The Saluda Member in Indiana is a northward-thinning wedge of dolomite, dolomitic limestone, and dolomitic mudstone with a colonial coral bed near its base (Brown and Lineback, 1966, pp. 1021, 1022). The Saluda is present at the base of the Whitewater Formation in the south (Clifty Power Plant section of Hattin et al., 1961, pp. 328-331; section 11), and within the Whitewater to the north. The dolomite content decreases northward, and at section 5 near the northern limit of the member, the colonial corals are overlain by limestone that is com- monly thickly-bedded. Except for the colonial coral bed, the Saluda Member contains very few fossils oth- er than ostracodes. Northeast.—The Richmond Group on the north- eastern side of the Cincinnati Arch region in Ohio (Text-fig. 3, sections 13, 14) is lithologically similar to the group in Indiana, but shale is more abundant in the Whitewater Formation, and the Saluda Member ts not present. Depositional Environments Previous Work.—Fox (1962) studied the composi- tion, texture, and structure of the sedimentary rocks, and the contained biota of the Richmond Group in Indiana. He concluded that the Dillsboro Formation was deposited in a stable marine environment below effective wave base. He found evidence of shoaling with some subaerial exposure in the Whitewater For- mation immediately below and above the Saluda Member, which formed in a lagoon that was periodi- cally subaerially exposed. Another episode of shoaling occurred during later *‘Whitewater’’ time. Fox (1968), on the basis of the sparite-micrite ratio in limestones, interpreted the Dillsboro as a regressive sequence in- terrupted near its end by a transgressive phase. Scotford (1965) studied the shale petrology of the ‘Waynesville’? in the Cincinnati Arch region and found sand and silt dominant in the south, and clay more abundant to the north. Kohut and Sweet (1968) noted that the Richmond Group is more argillaceous toward the south and grades into shales and limestones northward, where they suggested deposition occurred in deeper water. They recognized southern and north- ern conodont faunas with distributions probably relat- ed to water depth. Hatfield (1968) studied the lithostratigraphy and pa- leoecology of the lenticular Saluda Member on the western side of the Cincinnati Arch region in Indiana and Kentucky. The unit was deposited in a quiet, sa- line, very shallow to periodically subaerially exposed lagoon that was isolated by encompassing colonial coral—stromatoporoid banks. On the basis of lithology, Anstey and Fowler (1969) stated that water depth was at a maximum during *‘Arnheim-Waynesville”’ time, at a minimum during Saluda Member deposition, and of intermediate depth in the “Liberty” and **White- water’. W. D. Martin (1975, 1977) studied the com- position, texture, structure, and biota of Richmond Group limestones in Indiana and Ohio. He concluded that the Dillsboro Formation was deposited in a shal- low, generally low energy, offshore environment. Fol- lowing Saluda deposition, the Whitewater Formation formed in more normal marine conditions. A slight initial increase in water depth was followed by a slow decrease, resulting in offshore through nearshore and finally periodically subaerial environments. Hay (1977) discussed the Richmondian lithofacies sequence in Indiana. A regressive event at the end of ‘‘Arnheim’’ deposition may be marked by an uncon- formity. The transgression that followed culminated in the “‘late Waynesville—early Liberty’’, and the final regression with some oscillation occurred during the ‘“‘late Liberty—Whitewater—Elkhorn”’ interval. The stratigraphic ranges of a small number of conodonts characteristic of the European fauna extend into the Arnheim (Kohut and Sweet, 1968). This fauna is more conspicuously represented in pre-Maysvillian Ordo- vician strata of the Cincinnati Arch region. During late ‘‘Waynesville’’ time, an upper Richmond conodont fauna entered the region and reached its climax in the ‘Whitewater’. 12 BULLETIN 314 Swadley (1980) examined the Marble Hill bed on the west side of the Cincinnati Arch region and concluded that it represents an offshore bar—tidal channel com- plex along the northern edge of a shallow marine plat- form on which the Rowland Member of the Drakes Formation was deposited. Sediments of the Bull Fork Formation accumulated on an open marine shelf to the north. Present Study.—The nature of the Richmond Group around the entire Cincinnati Arch region is seen in the 14 composite stratigraphic sections examined herein (Text-fig. 3). The following characteristics are dem- onstrated: 1. The group thickens from about 45 m in the south to about 90 m in the north on both eastern and western sides of the region. 2. The argillaceous, silty, and dolomitic sediments of the south grade northward into interbedded shales and limestones. 3. Sections on the eastern side contain more shale and dolomite than those on the west, where limestone is more common. 4. Fossils generally increase in abundance northward, and are more common on the western side than on the east. 5. On the eastern side of the region, dolomitic shale of the Preachersville Member occurs at the top of the Richmond Group, whereas the lenticular Saluda Dolomite Member is present at or near the top on the western side from section 5 southward. 6. Colonial coral biostromes occur on the southeast- ern side of the region in the Otter Creek coral bed, and are prominent on the western side particularly in association with the Saluda Member. It is apparent from lithologies, thicknesses, and bio- ta that the Richmondian epicontinental sea in this re- gion became progressively deeper to the north, and depositional strike was oriented east-west. On the eastern side of the Cincinnati Arch region nearest the Queenston delta, marine environments were more re- stricted and terrigenous input was greater than to the west. Less restricted environments prevailed on the western side which faced the main body of the epi- continental sea, although in later Richmondian time the development of colonial coral banks resulted in Saluda deposition within a restricted lagoon. In some areas, an early Richmondian regression ap- pears to have been followed by a transgression. The top of the “‘Arnheim’’ in Indiana and the top of the Terrill Member of the Ashlock Formation in the south- eastern part of the Cincinnati Arch region may mark the end of this regression. Generally speaking, the Richmond Group as a whole represents a regressive sequence. Cincinnati Arch In Middle Silurian time the Cincinnati Arch was positive, relative to the subsiding Illinois Basin on the west and the Ohio Basin on the east. To the north, the Cincinnati Arch bifurcated into the Kankakee and Findlay Arches that marked the southern margin of the subsiding Michigan Basin (Shaver, 1974, fig. 6). These positive areas controlled the location and de- velopment of carbonate banks and reefs. The history of studies dealing with the time of initial relative uplift of the Cincinnati Arch was summarized by Scotford (1964). Few authors have considered the structure to be older than Silurian. Scotford (1964) ex- amined the problem on the basis of Ordovician shale petrology in the Cincinnati Arch region. In the ‘“Waynesville’’, the measured parameters vary in a north-south rather than east-west direction, indicat- ing that the axis of the arch was not a barrier to sedi- mentation. This variation would be expected with the east-west depositional strike and northward dip rec- ognized herein. At the top of the Richmond Group, six of eight significant parameters differ on the eastern and western sides of the arch. Scotford (1964, p. 436) stated that these data ‘‘suggest the possibility that a weak barrier may have been developing along the axis of the arch, but its influence on the character of the shales on opposite sides of the axis was minor.’ He felt that the Cincinnati Arch should not be assigned an age earlier than Silurian. If the Cincinnati Arch represents a broad, nearly level platform without a definite axis (Green, 1961), lithologies of this region as a whole should be com- pared with those to the east and west in order to de- termine its effects on sedimentation. During Rich- mondian time, deposition of the Richmond Group was confined to a narrow zone that extended from the pos- itive Nashville Dome northward along the Cincinnati Arch region (Text-fig. 2). These deposits formed a car- bonate belt separating the Queenston deltaic shales on the east and the Maquoketa marine shales on the west. Extensive colonial coral banks developed along the western margin of this belt, facing the main body of the epicontinental sea. The Cincinnati Arch appears to have been a subtle, broad platform sloping slightly to the north and influencing carbonate sedimentation and organic buildups during the Richmondian (Text- fig. 4). It was not until the Middle Silurian, when major basins subsided on either side, that the Cincinnati Arch became an obvious geologic feature. ORDOVICIAN RUGOSE CORALS: ELIAS 13 QUEENSTO Text-figure 4.—Middle Richmondian (*‘Liberty’’) paleogeography and lithofacies in a 90,000 km? area centered on the Cincinnati Arch region, as seen from the present northwest. Vertical scale greatly exaggerated. Richmond Group outcrop belt stippled. Colonial coral buildups shown in the southwestern Cincinnati Arch region. Arrows indicate paleocurrent directions. Based on data in Text-figures 2, 3, and 5, and Gray (1972). Solitary Rugose Corals Two species of solitary corals, Grewingkia cana- densis (Billings, 1862) and Streptelasma divaricans (Nicholson, 1875b), are present in the Richmond Group of the Cincinnati Arch region. Their distribu- tion and relative abundance are shown in Text- figure 3. Grewingkia canadensis (Billings, 1862) Stratigraphic Distribution.—Grewingkia canaden- sis 1s generally found within and on limestone beds containing common to abundant brachiopods and branching bryozoans. The earliest occurrence of this species at the base of the ‘Waynesville’ in the vicin- ity of sections 11 and 2 on the western side of the Cincinnati Arch region and section | on the east sug- gests introduction during an early Richmondian transgression. The initial distribution along deposi- tional strike about halfway between the deeper north- ern end and shallower, periodically subaerially ex- posed southern end of the region indicates preference for normal marine water in the intermediate depth range where calcium carbonate sediments accumulat- ed and brachiopods and bryozoans thrived. The species dispersed to the north and south as favorable environmental conditions appeared elsewhere, and was most widely distributed during the ‘‘Liberty—early Whitewater’. G. canadensis did not live in the re- stricted Saluda lagoon, or in very shallow environ- ments associated with the final regression at the end of the Richmondian. Orientation of Corals.—Growth lines, septal grooves, and interseptal ridges are rarely preserved on specimens of Grewingkia canadensis, and the outer portion of the stereozone generally is absent. Tips of the corals are almost always rounded, and calice rims of some were broken prior to deposition (PI. 8, fig. 25, Pl. 9, fig. 10). Corals oriented with calices approxi- mately horizontal and facing ‘“‘up’’, presumably in life position (Wells, 1957), are extremely rare. Of more than 500 specimens collected, two from interval 5c-1 of section 5 (UCGM 45288) and one from interval 14b- 1 of section 14 (UCGM 45465) were preserved in this way. All others were lying on their sides when buried (Pl. 3, fig. 13). Of 143 corals, 76 percent were oriented in the most stable position with an alar side facing ‘“‘up”’ (i.e., plane of curvature horizontal), and only 15 percent and 9 percent were deposited with the counter and cardinal sides ‘‘up’’, respectively. These features indicate that the corals were abraded and transported prior to final deposition and burial. The directional orientation of corals lying on bed- ding surfaces was measured at seven sections in the Cincinnati Arch region (Text-fig. 5). The distributions suggest preferential orientation related to predominant current directions. A unidirectional distribution would be expected if corals were oriented with tips facing the current. A symmetrical distribution with peaks 180 degrees apart could be produced in an oscillating cur- rent if they were oriented as above. However, it could also develop if these cylindrical objects were rolled perpendicular to a unidirectional or oscillating current 14 BULLETIN 314 with tips facing either way. A current from the south is suggested at section 4 and possibly section 11 on the western side of the Cincinnati Arch region. The distributions at sections 5 and 12 on the northwestern side of the region are somewhat bilaterally symmet- rical. This could reflect oscillating southwest—northeast and southeast-northwest currents at sections 5 and 12, respectively, if orientation was parallel to these direc- tions. If the corals were rolled perpendicularly, the currents may have been from the southeast and (or) northwest at section 5, and southwest and (or) north- east at section 12. On the northeastern side of the region at sections 13, 14, and 1, orientations suggest currents from the south and west. Unfortunately, few paleocurrent data from the Richmond Group of the Cincinnati Arch region are available for comparison. Bucher (1919, fig. 14h—k) presented a small number of pararipple strike directions. The predominant direc- tion in Indiana is east—northeast, but the significance of this is uncertain because localities from which data were combined are widely separated. Strike directions in Oldham County, Kentucky, are predominantly east-west. This is consistent with solitary coral ori- entations at section 4. Strike directions in Adams County, Ohio, and Fleming County, Kentucky, are predominantly north-northwest and north-south, re- spectively. These trends are consistent with coral ori- entations at section |. Potter and Pettijohn (1963, fig. 4-15) found that megaripples in limestones of the Cin- cinnatian Series, including a few from the Richmond- ian Stage in the vicinity of section 1, commonly strike approximately north-south. The average cross-bed- ding direction is to the west, although directions in quadrants containing Richmondian strata are to the north, south, and east. G. canadensis does not have a base of attachment, and clusters of individuals growing in lateral contact are rare (Pl. 9, fig. 17). The corals are ceratoid (PI. 9, figs. 1, 2) to trochoid (Pl. 8, fig. 25) and are generally slightly curved in early to intermediate stages, becom- ing cylindrical and straight in late stages (PI. 8, fig. 20, Pl. 9, fig. 2). They can be longer than 13 cm. This growth form suggests low energy, stable environmen- tal conditions in which the corals slowly sank verti- cally into the sediment because of weight added during growth (Wells, 1957). They were overturned, abraded, and transported in higher energy conditions before fi- nal deposition. Coral Size.—Length. The length-frequency histo- gram for Grewingkia canadensis in the Richmond Group of the Cincinnati Arch region is bimodal with peaks at 22.5 and 57.5 mm (Text-fig. 6). Similar dis- tributions are observed at all stratigraphic positions 12a-1to 6, 8. Whitewater Fm. Whitewater Fm. Sb-1,2 ar 13b-1. upper Dillsboro Fm 11b-2. upper Dillsboro Fm. ae Ss XN RICHMOND GROUP, OUTCROP BELT f- - SA ‘¥b-1. middie Bull Fork Fm. 4-4 Bardstown Mbr., Drakes Fm Text-figure 5.—Directional orientation of specimens of Grewing- kia canadensis (Billings, 1862) in the Richmond Group (see Text- figs. 3, 18, for stratigraphic positions). Orientation convention shown using north arrow as an example. All frequency distributions plotted to the scale shown in largest rose diagram (upper center of figure). n = number of specimens. and geographic locations within the region (Text-figs. 6, 7), and also in samples from Drummond Island, Michigan. The length-frequency histogram for the species cannot be understood completely because bi- ologic factors such as birth rate, growth rate, and death rate are unknown. However, the bimodal dis- tribution could be due to current sorting involving se- lective removal from an initial population of many in- dividuals less than about 57.5 mm long and especially about 37.5 mm long (Text-fig. 7A). Changes in external form and degree of septal dilation during ontogeny determined shape, surface area, and weight, which would have affected the motion of corals in currents. ORDOVICIAN RUGOSE CORALS: ELIAS l 10 fot 5 G6 30 The length-frequency histograms for specimens of G. canadensis from stratigraphic intervals 16a-1 and 16c-1 in the Goodlettsville-Gallatin area of Tennessee, and stratigraphic intervals 19a to e at Manitoulin Is- land, Ontario, are unimodal with peaks at 35 mm (Text-fig. 7). These peaks correspond to the low fre- quency area of the bimodal distributions (Text-fig. 7A, B). The very low frequency at 60 mm coincides with the maximum length of corals thought to have been removed from an initial population. Corals deposited in these stratigraphic intervals may have been trans- ported from elsewhere. Further evidence of extensive transport is discussed under ‘*‘Goodlettsville-Gallatin Area, Tennessee’’, and *‘Manitoulin Island, Ontario’’. It is noteworthy that the unimodal distributions occur in near-shore areas at extremes of the species’ geo- graphic range. The rapidly decreasing frequencies be- low about 35 mm in these distributions may indicate that all corals removed from an initial population were not deposited together. The smallest size fractions could have been transported elsewhere, perhaps even closer to shore. A possible example of this phenom- enon is discussed under ‘“‘Streetsville, Ontario’. Richmond Group 5@ length, mm Text-figure 6.—Length of specimens of Grewingkia canadensis (Billings, 1862) from the Richmond Group and two intervals within it, Cincinnati Arch region. %f = percent frequency. n = number of specimens. in 20 “Whitewater - Elkhorn” 10 50 90 “Liberty” n=49 10 50 90 length, mm n-247 7O 90 The bimodal length-frequency distributions for G. canadensis at localities in the Cincinnati Arch region are considered to be the result of current sorting. The similarity of these distributions geographically and stratigraphically indicates uniform conditions during periods of high energy. Predominant paleocurrent di- rections to the north and east suggest that corals re- moved from this region may have been deposited north of the present outcrop area and shoreward near the extremity of the Richmond Group to the east. If the corals removed by currents could be added to those left behind, it would be possible to reconstruct the length-frequency distribution of an initial G. can- adensis population. A combination of Text-figure 7A and 7B suggests that the distribution may have been unimodal and positively skewed, following the solid curve in 7A. Such a distribution resembles that for specimens of Streptelasma divaricans (Nicholson, 1875b), which were buried in life position or following very little transport (Text-fig. 14). Diameter. The diameter of specimens of Grewingkia canadensis was measured at a height between 45 and 55 mm above the tip (Text-fig. 8). At sections 2, 3, and 16 BULLETIN 314 30 30 19a toe ct n-14 a n-16 % 100 5 100 Text-figure 7.—Length (1) of specimens of Grewingkia canadensis ! (Billings, 1862) from Richmond Group sections (see Text-figs. 3, 18, S@C. 18 SES: 19 for locations and stratigraphic positions). %f = percent frequency. n = number of specimens. All measurements are in mm. 30 30 =53 =23 sec.12 * ‘ x ie ne % 100 05 100 30 30 24 =22 sec.5 * ; “sec. 14 % 100 % 100 sec.11 A) QS 8) z. E ve} fo} 3. 100 30 sec. 2 * pote % ; 100 30 sec. 3 * uate % ; 100 30 i n=13 n=231 sec. 4 * x “ 100 %f 0 er JX Cincinnati Arch Region S | veg 30 60 100 Sections + Section 18 | 30 16c-1 n:14 x sec. 16 5 100 ORDOVICIAN RUGOSE CoRALs: ELIAS 17 4 in the southwestern Cincinnati Arch region, almost all corals are 33 to 40 mm in diameter. At the other sections considered herein, most have a dia- meter of 22 to 32 mm. The significance of this distri- bution is discussed under “‘Summary”’ Epizoans.—Epizoic bryozoans, solitary Rugosa of Streptelasma divaricans, and colonial corals occur on Grewingkia canadensis. Bryozoans were noted on 54 percent of 529 corals collected in the Richmond Group of the Cincinnati Arch region. This percentage is ap- proximately the same at all stratigraphic sections. Of 36 corals for which the side facing ‘‘up’’ at the time of final deposition on a bedding surface is known, 39 percent have bryozoans on or mostly on the ‘‘up”’ side, 36 percent on or mostly on the ‘‘down”’ side, 11 percent on lateral sides, and on 14 percent they are evenly distributed around the exterior. This uniform cage ee sec. 18 sec. 19 40 | sec.]2 +! + al sec. 13 = o I je 2 SESS | 40 sec.5+; . | - sec. 14 45 h 55 4s h 55 | sec. 1] +! 205 - ss 40. F, 40 sec. 2 | Nes, |e 20 ——— Text-figure 8.—Diameter (d) of specimens of Grewingkia cana- densis (Billings, 1862) from Richmond Group sections (see Text- figs. 3, 18, for locations). Each specimen is measured once at a height (h) between 45 and 55 mm. All measurements are in mm. distribution on the upper exposed and lower buried sides suggests that bryozoans became associated with the host corals before they were deposited, probably while they were in life position. Burial after deposition was apparently rapid, not allowing time for epizoans to colonize the exposed surface. A total of 513 bryo- zoan colonies or groups of colonies on 279 corals are located as follows: 37 percent on the counter side, 38 percent on an alar side, and 25 percent on the cardinal side. Bryozoans do not show strong preference for a particular side of the host solitary corals. This has also been observed in the Selkirk Member of the Red River Formation (upper Middle or Upper Ordovician), southern Manitoba (Elias, 1981, pp. 5, 6). Epizoic corals assigned to S. divaricans are present on seven of 529 specimens of G. canadensis. These were found at intervals 5b-1 of section 5, 12a-1 of sec- tion 12, and 13b-1 of section 13, where both species are more abundant than usual (Text-fig. 3). Four epi- zoic corals are on the counter side of their host, two are on an alar side, and one is on the cardinal side. These epizoans may occur at any height above the host’s tip. Two were worn down to the base of at- tachment before burial, suggesting that they lived on the coral before it was abraded during transportation. One that grew upright from the inner and outer rim of the host’s calice probably became associated after death of the G. canadensis polyp but while the coral was still in life orientation. In some cases it is apparent that S. divaricans became epizoic on G. canadensis after transportation and deposition of the host (Pl. 3, fig. 13). Only one of 529 specimens of G. canadensis (from interval 12a-2 of section 12) has an epizoic colonial coral attached to its counter side. Borings.—Organisms that bored into corals of Grewingkia canadensis are annelids, bryozoans, and algae. Polychaete annelid borings, assigned to Trypanites weisei Magdefrau (1932), are straight to slightly curved with a circular cross-section (PI. 8, fig. 25, Pl. 9, fig. 10; Cameron, 1969, fig. 4g; Elias, 1980, p. 275). The diameter-frequency distribution of these borings in solitary corals from the entire Richmond Group, Cincinnati Arch region, is similar to that in brachiopods, bryozoans, and corals from the ‘“Waynesville”’ near section 14 (Text-fig. 9A, B). The borings have an average diameter that is larger than those from the White Head Formation (Ashgill) near Percé, Québec, but smaller than those from the Selkirk Member of the Red River Formation (upper Middle or Upper Ordovician) in southern Manitoba (Text-fig. 9C, D). T. weisei borings were seen in 38 percent of 466 specimens of G. canadensis from the Cincinnati 18 BULLETIN 314 30 20 10 %ft 10 G n=110 te) aS 1 diameter, mm 2 3 ie} 1 2 3 diameter, mm Z 3 diameter, mm Text-figure 9.—Diameter of borings assigned to Trypanites weisei Magdefrau (1932) in various Ordovician solitary rugose corals, brachio- pods, and bryozoans. %f = percent frequency. n = number of borings. A. Borings in 178 specimens of Grewingkia canadensis and two specimens of Streptelasma divaricans from the Richmond Group, Cincinnati Arch region. B. Borings in six solitary corals, 45 specimens of the brachiopod Hebertella insculpta, and 21 bryozoans from ‘‘Waynesville’’ strata, Richmond Group, near Waynesville, Ohio (from Cameron, 1969, fig. Sc). C. Borings in two specimens of Helicelasma and one specimen each of Grewingkia and Lobocorallium from the White Head Formation, Perce, Quebec. D. Borings in 108 specimens of Grewingkia, Helicelasma, and Deiracorallium from the Selkirk Member, Red River Formation, southern Manitoba (from Elias, 1976, fig. 17). Arch region. This percentage is approximately the same at all stratigraphic sections. The location of 1124 borings in 174 corals is as follows: 48 percent in the counter side, 36 percent in an alar side, and 16 percent in the cardinal side. If a// borings were produced after deposition of the hosts, most would be expected in an alar side, which usually faced “‘up’’. Predominance of T. weisei in the counter side must be due to preference of the boring organism when the coral was in life ori- entation. It is noteworthy that this preference is shown for slightly curved to straight corals of G. canadensis that were apparently oriented upright in the sediment, as well as for distinctly curved Selkirk Member corals that lay with the convex cardinal side in the sediment and the concave counter side facing upward during life (Elias, 1980, p. 275, fig. 5). Of 26 specimens of G. canadensis for which the side facing ‘“‘up’’ on the bed- ding surface at the time of final deposition is known, 61 percent have borings in or mostly in the “‘up”’ side, 31 percent have them uniformly distributed around the coral, and in 8 percent they are in or mostly in the “‘down’”’ side. This suggests that some boring occurred after deposition of the corals. Richards and Shabica (1969) found that borings in brachiopods of the *‘Arnheim-Waynesville”’ in the vicinity of section 5 were produced subsequent to deposition of the shells. Borings of ctenostomate bryozoans occur in only three of the corals collected for this study. All are from the ‘“‘Waynesville’’ at section 14. In one speci- men (UCGM 45468 from interval 14b-1), they are pres- ent in the cardinal side, and in the other two (UCGM 45469 from interval 146-1, UCGM 45470 from interval ORDOVICIAN RUGOSE CORALS: ELIAS 19 14b-2) the bryozoans bored into all sides. Pohowsky (1978, pl. 1, fig. 1) illustrated borings of Ropalonaria venosa Ulrich (1879) in a solitary coral from **Waynes- ville’ strata at Clarksville, Ohio. Dictyoporus retiformis (Palmer and Palmer, 1977) appears as fine, dendritic to reticulate networks of channels on the substrate surface that radiate from a nearly central point of origin. This ichnospecies, known previously from a hardground in the Rivoli Member of the Middle Ordovician Galena Group in Iowa (Palmer and Palmer, 1977, p. 186, fig. 6), is pres- ent in the cardinal-alar side of a single specimen of G. canadensis from interval 11b-1 at section 11 (UCGM 45304). A different ichnospecies, D. garsonensis Elias (1980), occurs in solitary rugose corals of the Selkirk Member, Red River Formation, in southern Manitoba. These borings may be of algal origin (Elias, 1980, pp. 273, 274, figs. 1-3). Microscopic algal borings in brachiopod shells from the Richmond Group of Ohio were described by Kob- luk and Risk (1977). The pyrite that partially or en- tirely fills these borings was thought to be related to the activity of sulfur-reducing bacteria, and to have been precipitated around a nucleus such as a bacteri- um or algal cell, or within a structure such as an algal cell or organic membrane, soon after burial. Similar borings are very common in G. canadensis. They pen- etrate perpendicularly a short distance into the host and are generally filled with pyrite (Pl. 9, fig. 20). That they were produced by algae is beautifully demon- strated by the presence of modern algal borings in one specimen (PI. 9, fig. 21). It was collected in a stream bed and the exposed surface was covered with a green algal film. Thin sections reveal very fine borings filled with green material that extend a short distance per- pendicular to the coral exterior. Unlike the Ordovician algal borings, they penetrate micrite and secondary calcite crystals filling Trypanites weisei borings. They are similar in morphology but are finer than the Or- dovician forms. Almost all the Ordovician microscopic algal borings occur in the outer coral wall. Their position in 38 spec- imens is as follows: 55 percent have borings in all sides, 13 percent only in the counter side, 3 percent in a counter-alar side, 10.5 percent in an alar side, 8 percent in a cardinal-alar side, and 10.5 percent in the cardinal side. The algae show no preference for a par- ticular location in the coral, and are generally present in all ontogenetic stages of the host. This, together with their common occurrence beneath epizoic bryo- zoans, suggests that boring took place very soon after secretion of the coral wall, while the host was in life position. In two specimens (UCGM 45212, 45226), borings penetrate septa from interseptal chambers, and in one of the specimens (UCGM 45226) they also enter the coral from a Trypanites weisei boring. These algal borings were probably produced after death and decay of the polyp. Microscopic algal borings are present in 93 percent of 57 corals from stratigraphic sections | to 5 and 10 to 14, for which thin sections were examined. The only stratigraphic sections at which all specimens do not have borings are 5, 12, and 13 in the northern part of the Cincinnati Arch region. The borings attain maxi- mum diameter and length at section 4 in the southwest, and are finer and very short at sections 12, 13, and 14 in the north. Modern boring algae flourish in intertidal environments and may be abundant to a depth of about 20 to 25 m (Bromley, 1970, p. 54). The ubiquity and greater size of algal borings in the southern Cincinnati Arch region may reflect the southward decrease in water depth. Intraspecific Variation.—Number of Septa. A gen- eral increase in the number of major septa at a partic- ular coral diameter within Grewingkia canadensis of the Richmond Group in the Cincinnati Arch region is indicated by comparing values for specimens from ‘Waynesville’, “‘Liberty’’, and ‘‘Whitewater-Elk- horn”’ strata (Text-fig. 10). At section | on the eastern side of the region, however, distributions through the entire group resemble those for *‘Liberty’’ strata else- where (Text-fig. 11). This is the only area in the Cin- cinnati Arch region where there are no major lithologic changes within the Richmond Group, except for an upward increase in shale that probably is related to progradation of the Queenston delta (Text-fig. 3). En- vironmental conditions apparently remained uniform during the Richmondian in the vicinity of section 1. The increase in number of septa elsewhere may have been the result of environmental change. Perhaps it was related to a decrease in water depth, as suggested by ‘‘Waynesville’’, ‘‘Liberty’’, and ‘‘Whitewater-Elk- horn’ lithologies (see ‘‘Depositional Environments’’). Differences in the number of septa at a particular di- ameter for samples from adjacent beds on Drummond Island, Michigan, and from geographically separated exposures of correlative strata on Manitoulin Island, Ontario, support the interpretation that this parameter was determined by environmental factors (see **Drum- mond Island, Michigan’’, and *‘Manitoulin Island, On- tario’’). Axial Region. The nature of the axial region in late ontogenetic stages within Grewingkia canadensis is highly variable. There is complete gradation among individual corals from those in which a very complex axial structure with many septal lobes and lamellae is 60 2.2: ante se, ies hy eer eC A a . ; 3 & A a Oo > 2 712 = 5 ee “Whitewater - Elkhorn” 2 XO 7 178 sections from 98 corals 60 agit hehe Baa: . —_e , “2° eee . ‘ Seatac ark Gentes P = 22 : = - n ° 020%" « . = we Oe Y “Liberty” ee 2@ yaa 123 sections from 63 corals ets “Waynesville” 63 sections from 35 corals 20 O 10 20 30 diameter, mm Text-figure 10.—Relation between number of major septa (n) and coral diameter in Grewingkia canadensis (Billi’ gs, 1862) from three intervals within the Richmond Group, Cincinnati Arch region. Numbers indicate frequency of a point if greater than one. Curves represent averages for the entire Richmond Group, Cincinnati Arch region, as determined in Text-figure 33. ORDOVICIAN RUGOSE CORALS: ELIAS 21 6O x x x x x x e x e e n 40 x e x ° e x O1c-2, 2 sections from 1 coral(s) x 1a-4, 10 24 “46 @eila-3, 7 e aa ¢ 1a-2, 45 sections from 18 corals D2@) A O 1a-1, 16 ay 5 6 y O 10 20 30 diameter, mm Text-figure 11.—Relation between number of major septa (n) and coral diameter in Grewingkia canadensis (Billings, 1862) from five intervals within the Richmond Group at section 1, Cincinnati Arch region (see Text-fig. 3 for stratigraphic positions). Numbers indicate frequency of a point if greater than one. Curves represent averages for the entire Richmond Group, Cincinnati Arch region, as determined in Text- figure 33. 5), 22 BULLETIN 314 20 10 °5 2@ 40 complex axial structure Richmond Group 40 -‘Liberty” n=29 + Waynesville” n=15 %t 20 / \ “Whitewater- / Va Elkhorn” n=33 100 comparative scale melts 60 80 comparative scale 100 open axial region Text-figure 12.—Percent frequency (%f) of values on the axial region comparative scale (see Pl. 7, figs. 1-21) for specimens of Grewingkia canadensis (Billings, 1862) from the Richmond Group and three intervals within it, Cincinnati Arch region. n = number of specimens. developed, to those having a simple axial structure with only a few septal lobes, to those in which major septa are withdrawn from the axis leaving an open axial region that lacks septal elements. To compare axial regions within this species, a scale was prepared using 21 specimens arbitrarily assigned values of 0, 5 ... 100 on the basis of decreasing axial region com- plexity as determined by visual comparison (PI. 7, figs. 1-21). Other corals were assigned values by visual comparison with this scale. The frequency distribution of values on the axial region comparative scale for G. canadensis from the entire Richmond Group in the Cincinnati Arch region has a peak at 35, indicating that most individuals have a moderately complex axial structure (Text-fig. 12). Although relatively few values are available for the “‘Waynesville’’, the frequency distribution has a peak at 35 with fairly low frequency below 25 and very low frequency above 45. The dis- tribution for specimens from the ‘‘Liberty”’ has a pro- nounced peak at 35, and frequency below 25 and above 45 is low. For the *‘Whitewater-Elkhorn’’, the greatest peak is at 65. There was apparently a trend in G. canadensis toward predominantly simpler axial regions, although the total range of variability re- mained approximately constant during the Rich- mondian. This trend, like the increase in number of septa, may have been related to decreasing water depth. Too few data are available to determine if fre- quency distributions of values on the axial region com- parative scale throughout section | on the eastern side of the Cincinnati Arch region resemble those for **Lib- erty’ strata elsewhere. Streptelasma divaricans (Nicholson, 1875b) Stratigraphic Distribution.—The distribution of Streptelasma divaricans generally parallels that of Grewingkia canadensis, but the latter species is more abundant (Text-fig. 3). ORDOVICIAN RUGOSE CORALS: ELIAS 23 75; 50 fof 25 n=189 solitary coralla, pseudocolonies, and colonies oO ] D. 3 4 5 6 number of corallites Text-figure 13.—Percent frequency (%f) distribution showing number of corallites per corallum in Streptelasma divaricans (Ni- cholson, 1875b) from the Richmond Group, Cincinnati Arch region. n = number of specimens. Orientation of Corals. —Whereas corals of G. can- adensis formed a transported constituent within and on carbonate beds, §. divaricans was epifaunal on sta- bilized carbonate substrates during periods of non-de- position. Septal grooves and interseptal ridges are commonly preserved, indicating little abrasion (Pl. 1, figs. 20, 27, 30, 33; Pl. 2, fig. 11; Pl. 3, fig. 11s). Energy conditions remained low, and subsequent generally argillaceous sediments buried many corals in an up- right position, apparently in life orientation (PI. 3, fig. 3). Some were deposited on their sides and a few at sections 12 and 13 are oriented with calices facing ‘“‘down’’, indicating transportation before final burial. Attachment sites centered on the cardinal side of 59 specimens of §. divaricans are as follows: 68 percent encrusting and branching bryozoans, 17 percent bra- chiopods (PI. 3, figs. 8s, 9s, 10), 8 percent Grewingkia canadensis (Pl. 3, fig. 13), 5 percent colonial corals (Pl. 3, fig. 12), and 2 percent pelecypods. The larvae frequently attached to living bryozoan colonies, as demonstrated by upward growth of the host around these epizoans (PI. 3, fig. 5s). The coral wall is some- times absent at the site of attachment, and septa are in contact with the bryozoan (PI. 3, fig. 7). The septa of S. divaricans are generally non-dilated, but in two specimens (UCGM 45018, 45128) they are moderately dilated where the corals are surrounded by bryozoans (Pl. 2, figs. 14). Dilation may have been a response to stress. The location of S. divaricans on brachiopods is shown in Table |. Richards (1972, p. 401) stated that ‘many of the corals are located [on Rhynchotrema dentatum and Lepidocyclus capax]| so that the polyp would have been bathed by the exhalent [sic] current. Perhaps the coral fed on food of a size or type systematically rejected by the brachiopod.” In interval 4-2 of section 4, 8. divaricans occurs at the uppermost points on colonial corals, some of which had been overturned before colonization. The species apparently favored elevated positions on stabilized substrates in low energy conditions. S. divaricans was not found in the Bull Fork Formation at section 1 on the eastern side of the Cincinnati Arch region, al- though G. canadensis is common (Text-fig. 3). This is the only area where there are no major lithologic changes within the Richmond Group. Perhaps depo- sition was more continuous and uniform, not allowing the species an opportunity to colonize stabilized sub- strates. Table 1.—Attachment sites of Streptelasma divaricans (Nichol- son, 1875b) on brachiopods from the Richmond Group, Cincinnati Arch region [data from Richards (1972) unless specimen number is given]. Rhynchotrema dentatum 9 on fold 5 off fold Lepidocyclus capax 2 on brachial valve, anterior (UCGM 45066, USNM 40086) 8 on fold Leptaena richmondensis 2 on geniculate part of pedicle valve Rafinesquina alternata 1 on pedicle valve, anterior (USNM 135767) Holtedahlina sulcata 1 on anterior 20 mre) 5 10 15 20 25 length, mm Text-figure 14.—Length of specimens of Streptelasma divaricans (Nicholson, 1875b) from the Richmond Group, Cincinnati Arch re- gion. %f = percent frequency. n = number of specimens. 4O “Whitewater - Elkhorn” 97 sections from 54 corals “Liberty” 55 sections from 33 corals O 8 16 diameter, mm Text-figure 15.—Relation between number of major septa (n) and coral diameter in Streptelasma divaricans (Nicholson, 1875b) from two intervals within the Richmond Group, Cincinnati Arch region. Numbers indicate frequency of a point if greater than one. Curves represent averages for the entire Richmond Group, Cincinnati Arch region, as determined in Text-figure 25. ORDOVICIAN RUGOSE CORALS: ELIAS \ vnitewater- 20 uy \ Elkhorn’ n= 34 comparative scale rt 1O “6 complex axial structure 20 4O Of 189 specimens of S. divaricans collected in this study, 74 percent are solitary coralla and 26 percent include two or more corallites in lateral contact (Text- fig. 13; Pls. 1-3). The maximum number seen in a sin- gle group is 13. Most clusters apparently represent pseudocolonies, with true coloniality being rare (see “Systematic Paleontology’’). This gregarious habit was probably due to selection of a favorable attach- ment site by more than one larva. Coral Size.—The length-frequency histogram for Streptelasma divaricans in the Richmond Group of the Cincinnati Arch region is shown in Text-figure 14. This unimodal, positively skewed distribution proba- bly reflects the population because many corals were preserved in life position and few show signs of ex- tensive transport. The longest corals occur at section 4 on the south- western side of the Cincinnati Arch region. The sig- nificance of this is discussed under *‘Summary’’. Epizoans.—Epizoic organisms are very rare on Streptelasma divaricans, probably because of small coral size. Bryozoans are present on several larger Richmond Group 100 Open axial region 60 comparative scale Text-figure 16.—Percent frequency (%f) of values on the axial region comparative scale (see Pl. 1, figs. 1-19) for specimens of Streptelasma divaricans (Nicholson, 1875b) from the Richmond Group and two intervals within it, Cincinnati Arch region. n = number of specimens. 80 specimens at intervals 4-3 and 4-5 of section 4, and interval 12a-9 of section 12. Borings.—Borings assigned to Trypanites weisei were seen in only two specimens of Streptelasma di- varicans from interval 4-5 of stratigraphic section 4. Microscopic algal borings are present in 71 percent of 45 specimens from the Cincinnati Arch region for which thin sections were examined. Corals without algal borings are not restricted to the northern part of the region, as in Grewingkia canadensis. However, the borings are best developed south of stratigraphic sections 12, 13, and 14, possibly reflecting the south- ward decrease in water depth. The lower frequency of borings in S. divaricans than in G. canadensis may be related to the smaller coral size and the fact that the coral wall was frequently surrounded and protected by living host bryozoans. Intraspecific Variation.—The number of major sep- ta at a particular diameter is highly variable within Streptelasma divaricans of the Richmond Group, Cin- cinnati Arch region. Unlike Grewingkia canadensis (see Text-fig. 10), there is no marked difference in 26 BULLETIN 314 values for corals from “‘Liberty’’ and ‘*Whitewater- Elkhorn” strata (Text-fig. 15). The nature of the axial region in late ontogenetic stages within S$. divaricans is highly variable. There is complete gradation among individual corals from those in which a moderately complex axial structure of septal lobes and lamellae is developed, to those with a simple axial structure of only a few septal lobes, to those having major septa that extend to the axis with- out forming an axial structure, to those in which major septa are withdrawn from the axis leaving an open axial region lacking septal elements. To compare axial regions within this species, a comparative scale similar to that for G. canadensis was prepared, using 19 spec- imens assigned values of 5, 10. . . 95 on the basis of decreasing axial region complexity (Pl. 1, figs. 1-19). Other corals were assigned values by comparison with this scale. The frequency distribution of values on the axial region comparative scale for S. divaricans from the Richmond Group in the Cincinnati Arch region has a peak at 65, indicating that most individuals have major septa extending to the axis without forming an axial structure (Text-fig. 16). The frequency distribu- tion for specimens from the “‘Liberty’’ has a broad peak centered about the value 65. For the overlying *“Whitewater-Elkhorn’’, a sharp peak is present at 65 and frequency below 40 is lower than in the “*Liberty”’ distribution. As in G. canadensis, there was appar- ently a trend toward predominantly simpler axial re- gions, although the total range of variability remained approximately constant through the Richmondian. The axial regions of corallites within pseudocolonies and colonies are the same or similar in complexity. In pseudocolonies, this could reflect the similar environ- ment they shared. Similarity within colonies could have been environmentally or genetically controlled. If the trend toward predominantly simpler axial re- gions was a response to environmental change, it may have been related to decreasing water depth, as pre- viously discussed for G. canadensis. Summary In general, the Richmond Group of the Cincinnati Arch region represents a regressive sequence, possi- bly following a transgressive event in early Rich- mondian time. The argillaceous, silty, and dolomitic sedimentary rocks of the south grade northward into interbedded shales and limestones. Water depth be- came progressively greater northward, and deposi- tional strike was oriented east-west. On the eastern side of the region nearest the Queenston delta, marine environments were more restricted and terrigenous in- put was greater than on the western side, which faced the main body of the epicontinental sea. In these less restricted environments, extensive development of co- lonial coral banks temporarily produced a restricted lagoon in later Richmondian time. On the southwest- ern side of the Cincinnati Arch region, algal borings were best developed, colonial coral biostromes were most prominent (Browne, 1964, p. 389), and Grewing- kia canadensis and Streptelasma divaricans attained their greatest diameter and length, respectively. This shallow, open shelf edge of the Richmond Group car- bonate belt must have been an area of high productiv- ity that was especially favorable for corals. The Cin- cinnati Arch was probably a subtle, broad platform sloping slightly to the north and influencing carbonate sedimentation and organic buildups during the Rich- mondian. Grewingkia canadensis (Billings, 1862) and Strep- telasma divaricans (Nicholson, 1875b) are the only solitary rugose corals known from the Cincinnatian Series of the Cincinnati Arch region. They first ap- peared at the base of the ‘‘Waynesville’’ in the Rich- mond Group, suggesting introduction during an early Richmondian transgression. Both species have a sim- ilar stratigraphic distribution, and favored normal ma- rine waters of intermediate depth where calcium car- bonate sediments accumulated and brachiopods and bryozoans thrived. G. canadensis probably lived in stable, low energy environments, but the corals were transported in higher energy conditions before final deposition and rapid burial. Many of those less than about 60 mm and especially about 35 mm long were removed from the region. Whereas specimens of G. canadensis formed a clastic constituent within and on carbonate beds, §. divaricans was epifaunal on sta- bilized carbonate substrates during periods of non-de- position. The larvae commonly attached to elevated areas, especially on bryozoans. Energy conditions re- mained low, and subsequent generally argillaceous sediments often buried the corals in life position. In both G. canadensis and §. divaricans there was a trend toward predominantly simpler axial regions, al- though the total range of variability remained approx- imately constant. The average number of septa in G. canadensis generally increased during Richmondian time, but remained constant in the vicinity of section 1 on the eastern side of the Cincinnati Arch region where environmental conditions were apparently rel- atively uniform. These trends may have been related to decreasing water depth. During the final regression of the epicontinental sea at the end of the Richmond- ian, G. canadensis and S. divaricans became extinct. ORDOVICIAN RUGOSE CORALS: ELIAS Dil Burkesville, Kentucky In the vicinity of Burkesville (Text-fig. 2, area No. 2), the Richmond Group is represented by the 6 to 40 m thick Cumberland Formation, a predominantly un- fossiliferous, fine-grained dolomite (Text-fig. 3). The dolomite is generally massive, but burrows and very fine laminae (?stromatolites) are also present. The for- mation was probably deposited in restricted, very shallow marine environments. A thin unit of limestone with shale interbeds occurs locally near the base, and was termed the Burkesville limestone by Jillson (1951). Calcilutite with birdseye structures is present in this unit, as well as a few brachiopods, branching bryozoans, and gastropods. This unit probably rep- resents a brief normal marine incursion. Jillson (1951, pp. 13, 14) listed a diverse fauna that pointed ‘‘rather conclusively to the Waynesville age of the Burkesville limestone.’’ Near the top of the Cumberland Forma- tion, local limestone lenses and shale interbeds are also present. At interval 15b of section 15, 1 m of limestone is overlain by 0.2 m of shale. The limestone contains some branching bryozoans, brachiopods, and gastropods, and probably represents a short, normal marine interval. Also present are fine laminae and limestone pebble conglomerate, suggesting deposition in very shallow marine to possibly subaerial condi- tions. Jillson (1953) described the Haggard limestone from an approximately correlative position in interval 15d of section 15. He listed a solitary coral, the co- lonial genera Columnaria (?=Favistina), Calapoecia, and Tetradium, as well as brachiopods, bryozoans, and a few other fossils that distinguish this limestone ‘indisputably as a correlative of the Liberty division of the Richmond”? (Jillson, 1953, p. 9). All exposed bedrock seen at this stratigraphic position is unfossi- liferous dolomite. Loose blocks of fossiliferous calci- lutite and calcarenite containing brachiopods, bryo- zoans, and typical Richmond Group colonial corals were found. Solitary Rugosa were not seen, and the location and identity of the specimens Jillson assigned to Streptelasma rusticum remains unknown. The pres- ence of ‘‘Liberty”’ strata about 10 m below the top of the Cumberland Formation suggests that little was re- moved by post-Richmondian—pre-Devonian erosion. Foerste (1912a, p. 447) reported solitary and colo- nial corals, and stromatoporoids east of Burkesville in Wayne County, Kentucky. He stated that this section probably correlates with the basal ‘‘Liberty”’. Goodlettsville-Gallatin Area, Tennessee The Nashville Dome is known to have been period- ically positive since the early Middle Ordovician (C. W. Wilson, 1935). It was uplifted above sea level dur- ing the late Maysvillian, and remained so except lo- cally until the Mississippian. Richmondian sediments of the Arnheim and overlying Fernvale Formations were deposited on the western and northern sides of the dome (Bassler, 1932, pp. 120-130; C. W. Wilson, 1949, pp. 201-207, 212-215). Clastic and carbonate sediments forming the Sequatchie Formation to the east (C. W. Wilson, 1949, pp. 209-211) intertongue at various positions in the Arnheim-Fernvale sequence on the north side of the Nashville Dome. The Rich- mond Group is overlain by the middle Llandovery (Lower Silurian) Brassfield Formation. At locality 16c, the basal Brassfield contains abundant solitary corals. In the Goodlettsville-Gallatin area north of Nash- ville (Text-fig. 2, area No. 3), the Richmond Group varies from about 6 to 35 m in thickness (Text-fig. 3). The Arnheim Formation consists of rubbly-bedded argillaceous limestone with gray shale interbeds. The fauna was discussed by Foerste (1912a, pp. 446, 447), and listed by Bassler (1932, p. 124) and C. W. Wilson (1949, p. 207). Brachiopods are most abundant, and solitary corals are common. The Fernvale Formation consists of thicker and more evenly-bedded crinoidal calcarenites, and smaller amounts of finely-laminated calcilutite, with shale interbeds. Brachiopods and bryozoans are common, but solitary corals are rare. Fossils from the shale equivalent of the Fernvale were listed by C. W. Wilson (1949, p. 215). A western tongue of the Sequatchie Formation occurs at the top of the Richmond Group in the Goodlettsville-Gallatin area. It consists primarily of massive, unfossiliferous, argillaceous sandstone with some burrows and fine laminae. A few thin beds of calcilutite with birdseye structures and fine laminae are present locally. Several very thin lenses of fossils including common solitary corals and brachiopods occur in the sandstone. The Richmondian sequence on the northern margin of the Nashville Dome appears to be regressive. The Arnheim was deposited in fairly low energy condi- tions, as indicated by the lithology (Howe, 1969, p. 1334). Fernvale sediments suggest a higher energy shoal (Howe, 1969, p. 1333). The lithology and sedi- mentary structures of the Sequatchie tongue indicate very shallow marine to possibly occasionally subaerial environments. Bassler (1932, pp. 122, 124) noted that brachiopods in the Arnheim Formation of Tennessee are charac- teristic of “‘Arnheim”’ strata in Ohio, but some of these and other fossils are also typical of the **Waynes- ville’. Howe (1969, pp. 1335, 1336) stated that the fauna of the Arnheim Formation indicates a Richmon- 28 BULLETIN 314 60 n ao a re) 8 ‘ O x x2 OO y ) O Sequatchie Fm.(16c-1) 17 sections from 10 corals ‘: z= ” By (16b-2). Sais ae 2S Wee O Fernvale Fm. 6 By hae uy 20 x Arnheim Fm. 23s eae 4 ze O 10 2@ 30 40 diameter, mm Text-figure 17.—Relation between number of major septa (n) and coral diameter in Grewingkia canadensis (Billings, 1862) from four intervals in the Richmond Group, Goodlettsville-Gallatin area, Tennessee (see Text-fig. 3 for locations and stratigraphic positions). Numbers indicate frequency of a point if greater than one. Curve represents averages for the entire Richmond Group, Cincinnati Arch region (see Text- fig. 33). dian age, but does not warrant precise correlation with the type Richmondian of the Cincinnati Arch region. On the basis of stratigraphic position, the Arnheim Formation of Tennessee may be equivalent to the ‘‘Arnheim-Waynesville’’. If the lower Arnheim For- mation proves to be ‘“‘Arnheim”’ in age, it contains the oldest solitary corals known in the Richmond Group. The stratigraphic position and predominance of lime- stone in the Fernvale Formation near Goodlettsville suggest correlation with the ‘‘Liberty’’. The upper tongue of the Sequatchie Formation may correspond to the “‘Whitewater-Elkhorn’’. Howe (1969, p. 1335) found that diagnostic Richmond Group brachiopods occur in the Arnheim and basal Fernvale Formations, whereas Maquoketa Group brachiopods are restricted to higher strata. Grewingkia canadensis (Billings, 1862) is the only solitary coral known from the Richmond Group in the Nashville Dome area. The corals were abraded (PI. 10, fig. 1) and deposited on their sides before burial. Epizoic bryozoans are rare, and were seen on only two of 36 specimens. Borings assigned to Trypanites weisei are rare. Microscopic algal borings were seen in only one of nine corals for which thin sections were examined, but the stereozone is poorly preserved in specimens from this area. The length-frequency distribution for corals in the Arnheim Formation suggests that most if not all were transported from elsewhere, as previously discussed for G. canadensis under “‘Cincinnati Arch Region’”’ (Text-fig. 7). The source remains unknown because paleocurrent data are not available for this area. The number of major septa at a particular diameter in cor- als from the Arnheim Formation corresponds to those from ‘‘Waynesville’’ strata in the Cincinnati Arch re- gion (Text-figs. 10, 17), suggesting that the solitary Rugosa lived in similar environments. Values for cor- als from the Fernvale Formation are similar to those from the ‘‘Liberty’’ of the Cincinnati Arch region. Solitary Rugosa in a thin, fossiliferous lens within the Sequatchie Formation (interval 16b-2 of section 16) are unusually long and broad (UCGM 45517, ORDOVICIAN RUGOSE CORALS: ELIAS 29 45518, 45521). They exceed 60 mm in length, which is thought to be the maximum size removed by currents from an initial population (Text-fig. 7). These corals may have lived in the Goodlettsville area, or been transported in higher energy conditions than occurred elsewhere. Values for the number of major septa at a particular diameter are typical of the *‘Whitewater- Elkhorn” in the Cincinnati Arch region (Text-figs. 10, 17). Corals in another similar lens within the Sequatch- ie Formation (interval l6c-1 of section 16) have a length-frequency distribution suggesting that they were transported from elsewhere, as previously dis- cussed (Text-fig. 7). Two of the 16 specimens collected from this interval had the stereozone completely re- moved prior to deposition, indicating extensive abra- sion. Values for the number of major septa at a par- ticular diameter are typical of the ‘‘Waynesville’’ in the Cincinnati Arch region and Arnheim Formation of Tennessee (Text-figs. 10, 17). It is possible that corals in this lens were reworked from the Arnheim and de- posited in the clastic Sequatchie tongue. They are slender, having diameters similar to specimens in the Arnheim Formation and in the northwestern and east- ern Cincinnati Arch region (Text-fig. 8). One specimen (UCGM 45533) consists of three small coralla, but it is not known if these represent a pseudocolony or col- ony. Little Sturgeon Bay, Wisconsin Allen and Stieglitz (1981) recognized the Scales Shale, Fort Atkinson Dolomite, and Brainard Shale units of the Maquoketa Group in eastern Wisconsin. Silicified, poorly preserved specimens of Grewingkia canadensis (Billings, 1862) and typical Richmond Group colonial corals occur in dolomite at the top of the group at Little Sturgeon Bay (Text-fig. 2, area No. 4; Text-fig. 18). Chamberlin (1883, p. 171) reported that carbonate beds in this area grade into shales to- ward the south and west. The dolomite beds contain- ing these corals may represent a westward shift of the Richmond Group facies associated with regression of the epicontinental sea at the end of Richmondian time. Unstudied solitary corals also occur in the Fort At- kinson Dolomite in eastern Wisconsin (P. E. Allen, 1981, pers. comm.). If these prove to be species char- acteristic of the Richmond Group rather than of the Maquoketa Group in Illinois and Iowa, intertonguing of the two units would be indicated. The section at Little Sturgeon Bay may be crucial in correlating Up- per Ordovician type sections of the Cincinnati Arch region with strata to the west. Little Bay de Noc, Michigan In northern Michigan, the Richmond Group is ex- posed on the peninsula between Little Bay de Noc and Big Bay de Noc (Text-fig. 2, area No. 5; Text-fig. 18). It comprises the upper Stonington, Big Hill, and Mor- mon Creek Formations. Conodonts in the Stonington and Big Hill indicate a late Maysvillian—Richmondian age (Votaw, 1981). The basal beds of the 12 m thick Bay de Noc Member of the Stonington Formation are considered Maysvillian (Liberty and Shelden, 1968, fig. 8, p. 28). The Richmondian portion consists of rubbly-bedded argillaceous limestone with gray shale interbeds (Hussey, 1926, p. 149; 1950, pp. 16, 17). The proportion of limestone and abundance of fossils in- crease upward. At locality 17a, a few pelecypods and trilobites occur in the lower part, and brachiopods and some bryozoans are present in thin lenses and beds within limestone higher in the member. Hussey (1950, pp. 17, 18) listed the fauna. Foerste (1918, p. 99) found a solitary coral, assigned herein to Streptelasma di- varicans (Nicholson, 1875b), 3 m below the top. The specimen consists of two adjacent coralla near the an- terior margin of a pedicle valve of Rafinesquina (PI. 3, fig. 14s). Foerste also found solitary corals, assigned herein to Grewingkia deltensis n. sp., at the top of the member. The Bay de Noc Member probably repre- sents a shallowing upward sequence deposited in a normal marine environment. Foerste (1918, pp. 125, 126) suggested that fossils in this member (his ‘‘argil- laceous Richmond limestone’’) ‘“‘may represent a late stage of the Waynesville fauna or an early stage of the post-Waynesville.”’ Hussey (1926, p. 144) noted that the presence of many ‘“‘Waynesville’’ and *‘White- water’ fossils together with ‘‘Elkhorn’’ taxa made positive correlation unwise, but suggested that the up- per part of the Bay de Noc Member may be ‘*White- water’ in age. The position of the Bay de Noc Mem- ber at the base of the Richmondian stratigraphic section, the general lithology and abundance of shale, and the rarity of solitary corals suggest it may corre- late with the ‘‘Arnheim-Waynesville’’ interval in the Cincinnati Arch region. The overlying Ogontz Member of the Stonington Formation is | to 6 m thick and consists of cherty, relatively pure micritic limestone with argillaceous material in irregular bands and lenses. An intrafor- mational conglomerate of irregular nodules and thin slabs of Ogontz limestone is present near the top of the member (Hussey, 1926, pp. 135-138; 1950, p. 17). Hussey (1950, pp. 19, 20) listed the fauna. Grewingkia deltensis is common on some surfaces of Ogontz lime- stone, where individuals tend to occur in groups, in 30 BULLETIN 314 association with small gastropods and some brachio- pods. These corals were abraded and their tips round- ed before burial (Pl. 11, figs. 1, 9). Of the specimens observed in situ, two were buried with the counter side “‘up’’, six had an alar side “‘up’’, and one had the cardinal side “‘up’’. G. deltensis is trochoid, moder- ately curved, and attains large size. It resembles species of Grewingkia in the Red River Formation (upper Middle or Upper Ordovician) of southern Man- itoba, which were probably oriented during life with the convex cardinal side in the sediment and counter side facing upward (Elias, 1980, fig. 5; 1981). None of the collected specimens have epizoans or borings as- signed to Trypanites weisei. Both corals for which thin sections were examined have Ordovician microscopic algal borings, and one also has similar modern borings produced by algae in Lake Michigan (Pl. 11, fig. 8). The Ogontz Member was deposited in a shallow ma- rine environment with little terrigenous influx, possi- bly in a sheltered lagoon as suggested by the micritic composition and common gastropods. The intrafor- mational conglomerate may indicate a period of sub- aerial exposure near the end of Ogontz deposition. The relatively pure micritic limestone characterizing this member is not found elsewhere in the Richmond Group. Foerste (1918, p. 125) provisionally correlated this unit (his “‘cherty Richmond limestone’’) with the “‘post-Waynesville’’ on the basis of the fauna. Hussey (1926, p. 144) suggested that it may be equivalent to the “‘Whitewater’’. The position of the Ogontz Mem- ber in the stratigraphic sequence, the predominance of limestone, and the relative abundance of solitary corals suggest it may correlate with the “‘Liberty’’. Overlying the Stonington Formation is the 38 m thick Big Hill Formation. It consists of dolomite with some shale partings (Ehlers, Kesling, and Slaughter, 1967, p. 225). In a quarry near the base of the for- mation (locality 17b), burrows and planar laminae are present. Hussey (1950, pp. 21, 22) listed the fauna. Abundant colonial corals of Palaeophyllum and Hal- ysites (=Catenipora) and numerous bryozoans occur throughout the unit (Ehlers, Kesling, and Slaughter, 1967, p. 228). Near the base, the typical Richmond Group colonial corals Calapoecia, Palaeophyllum, Favistella (?=Favistina), and Halysites (=Cateni- pora) are abundant (Hussey, 1926, p. 145; 1950, p. 21). Near the top, Palaeophyllum and Halysites (=Caten- ipora) were reported (Ehlers, Kesling, and Slaughter, 1967, p. 225). Solitary corals are rare to common in association with colonial forms near the base of the formation at locality 17c, but are too poorly preserved for identification. Ehlers, Kesling, and Slaughter (1967, p. 225) reported solitary Rugosa below the very fossiliferous colonial coral beds at the top of the unit. The lithology and sedimentary structures of the Big Hill Formation suggest deposition in periodically semi- restricted, shallow marine environments, perhaps fre- quently in lagoons behind colonial coral banks. The formation resembles the Saluda Dolomite Member of the western Cincinnati Arch region. Hussey (1926, pp. 148-150) considered correlation of the Big Hill For- mation uncertain, but suggested it may be near the ““Whitewater-Elkhorn’’. Its stratigraphic position above the Ogontz Member but below the Mormon Creek Formation, the dolomitic composition, and the presence of colonial coral beds and solitary corals sug- gest correlation with the *‘Whitewater’’. The 36 m thick Mormon Creek Formation overlies the Big Hill Formation (Kesling, 1975, pp. 5-7). It con- sists of thinly-bedded dolomite alternating with bands of shale, and contains gypsum and hopper-shaped ha- lite molds. One species of ostracode is abundant on some bedding planes, and trace fossils are present at certain horizons. Kesling (1975, p. 6) considered the formation to have been deposited in a brine-filled, re- stricted basin. Evaporite-producing environments did not occur elsewhere in eastern North America during the latest Ordovician. The position of the Mormon Creek Formation as the final unit in a regressive se- quence at the top of the Richmondian stratigraphic section suggests that it may correlate with the “*Elk- horn’. Drummond Island, Michigan The Richmond Group is exposed on the north shore of Drummond Island (Text-fig. 2, area No. 6; Text-fig. 18). South of locality 18a, Hussey (1952, pp. 49, 50) reported a stromatoporoid “‘reef’’ extending under the water, overlain by 2 m of sandy dolomitic limestone, followed by another stromatoporoid—colonial coral ‘reef’. These “‘reefs’’ are equivalent to similar bio- stromes at the top of the Meaford beds on Manitoulin Island, Ontario. Hussey termed these strata **White- water member’’, and listed the fauna. At locality 18a, 0.5 m of rubbly limestone with uncommon to common solitary corals and a few brachiopods (interval 18a-1) is overlain by a 0.3 m thick colonial coral bed with the typical Richmond Group genera Favistina and Cala- poecia and uncommon solitary corals (interval 18a-2). Many of the colonial corals are overturned. This bed is overlain by 0.6 m of more massive limestone con- taining abundant solitary Rugosa and sparse brachio- pods at the top (interval 18a-3). Orientation of the sol- itary corals is shown in Text-figure 5. At locality 18), the rubbly-bedded, argillaceous limestones and shales of the Meaford beds are exposed (Hussey, 1952, pp. ORDOVICIAN RUGOSE CORALS: ELIAS 31 60 n4O0 O x 18a-3 wan © 18a-1, 2: 18b-1 9 sections from 4 corals 26a? is eS diameter, mm Text-figure 19.—Relation between number of major septa (n) and coral diameter in Grewingkia canadensis (Billings, 1862) from intervals within the upper Meaford beds, upper member, Georgian Bay Formation, Drummond Island, Michigan (see Text-fig. 18 for stratigraphic positions). Curve represents averages for the entire Richmond Group, Cincinnati Arch region (see Text-fig. 33). 50, 51). Near the base of the section, several fossilif- erous surfaces with brachiopods, branching bryozo- ans, and uncommon to common solitary corals are present. The fauna was listed by Hussey (1952, p. 51). North of locality 18c, Hussey (1952, p. 50) reported Meaford beds (his *‘Whitewater member’’) and listed the fauna. At locality 18c, massive, thickly-bedded, vuggy dolomite with branching bryozoans represents the overlying Kagawong beds of Manitoulin Island. Solitary corals were not seen in this unit on Drum- mond Island. Grewingkia canadensis (Billings, 1862) is the only solitary rugose coral known from Drummond Island. The corals were abraded before final burial (PI. 10, fig. 15). In intervals 18a-1 to 3 and 18b-1 of section 18, sixteen of 19 specimens were oriented at the time of final burial with an alar side ‘“‘up’’, two with the count- er side ‘“‘up’’, and one with the cardinal side “‘up”’ The length-frequency distribution is bimodal, suggest- ing that some corals were removed from the area, as previously discussed for G. canadensis under **Cin- cinnati Arch Region”’ (Text-fig. 7). Very long speci- mens are relatively common in the solitary coral bed of interval 18a-3. Coral diameters are similar to those of specimens from the northwestern and eastern Cin- cinnati Arch region and Manitoulin Island (Text-fig. 8). The distribution of the number of major septa at a particular diameter for specimens from intervals 18a- 1 and 2, and 185-1 in the upper Meaford beds of Drum- mond Island is similar to that for the *“Waynesville”’ in the Cincinnati Arch region (Text-figs. 10, 19). The higher values in the horn coral bed (interval 18a-3) immediately above intervals 18a-1 and 2 resemble those for the *‘Whitewater-Elkhorn’’, possibly indi- Table 2.—Frequency (f) of values on the axial region comparative scale (see Pl. 7, figs. 1-21) for specimens of Grewingkia canadensis (Billings, 1862) from the Meaford beds, upper member, Georgian Bay Formation, Drummond Island, Michigan, and Manitoulin Island, Ontario. n = number of specimens. Axial Region Comparative Scale Values: Drummond Is., n=7 fie Manitoulin Is., n=9 2 32 BULLETIN 314 cating shallower water. The frequency distribution of values on the axial region comparative scale for the few available specimens has a peak at 35, as does the distribution for the *‘Waynesville-Liberty’’ in the Cin- cinnati Arch region (Table 2; Text-fig. 12). Epizoic bryozoans and borings assigned to Trypanites weisei appear to be rare at Drummond Island. Microscopic algal borings are present in all five corals for which thin sections were examined. Manitoulin Island, Ontario The Richmondian stratigraphy and fauna of Mani- toulin Island (Text-fig. 2, area No. 7; Text-fig. 18) were described by Foerste (1912b; 1916, pp. 97-127; 1924, pp. 53, 54) and Caley (1936). The strata are presently included in the Georgian Bay Formation, which is Maysvillian and Richmondian in age (Liberty and Shelden, 1968, pp. 30, 31, fig. 8; Liberty, 1969, pp. 73-79). The upper, Richmondian portion of its 45 to 100 m thick lower member (Wekwemikongsing beds) consists of shale, with a few thin dolomite interbeds toward the top. Brachiopods, bryozoans, pelecypods, and gastropods are the dominant fossils. Solitary cor- als assigned to Grewingkia canadensis (Billings, 1862) occur in a dolomite bed near the top of the Wek- 60 n40 Zoo e Meaford Beds (19a, c, d-1) DE Herr ois inn Perit O Wekwemikongsing Beds (M75) wemikongsing beds at locality M75. The distribution of the number of septa at a particular coral diameter is similar to that for ‘‘Liberty”’ strata in the Cincinnati Arch region (Text-figs. 10, 20). The lower member of the Georgian Bay Formation appears to have been deposited in a normal marine environment, and the upward increase in the frequency of carbonate beds and fossils may indicate a shallowing sequence. The stratigraphic position of the upper portion of the lower member and the abundance of shale suggest it may correlate with the *‘Arnheim-Waynesville”’ of the Cin- cinnati Arch region. The overlying Meaford beds of the upper member of the Georgian Bay Formation consist of about 15 m of rubbly-bedded, argillaceous limestone with gray shale interbeds. Brachiopods and branching bryozo- ans are the most common fossils. Typical Richmond Group colonial coral-stromatoporoid beds occur near the base and top of the unit. The fauna and lithology suggest deposition in a shallow, normal marine envi- ronment with colonial coral-stromatoporoid banks de- veloping at the beginning and end of deposition. The upward increase in limestone at locality 19d may in- dicate a shallowing sequence. Foerste (1916, p. 104; 1924, p. 51) considered the fauna of the Meaford beds e a] e Ye e ce) iS 19 sections from 13 corals (M61a, GSC 8530) 19 a a es " 4 id "4 a O 10 20 30 diameter, mm Text-figure 20.—Relation between number of major septa (n) and coral diameter in Grewingkia canadensis (Billings, 1862) from intervals within the Georgian Bay Formation, Manitoulin Island, Ontario (see Text-fig. 18 for locations and stratigraphic positions). Numbers indicate frequency of a point if greater than one. Curve represents averages for the entire Richmond Group, Cincinnati Arch region (see Text-fig. 33). ORDOVICIAN RUGOSE CORALS: ELIAS 33 to be upper *‘Waynesville’’. The stratigraphic position and predominance of limestone suggest correlation with the ‘‘Liberty’’. Grewingkia canadensis is rare to common at seven of ten Meaford exposures that were examined. Spec- imens are most frequent near the base and top of the unit, and usually occur with brachiopods and branch- ing bryozoans. At locality 19a they are associated with gastropods and brachiopods. Solitary corals are absent in most of the colonial coral—stromatoporoid beds that were seen, but are rare in the Favistina bed at the top of the Meaford in interval 19d-3 at locality 19d. Epi- zoic bryozoans and borings assigned to Trypanites weisei are uncommon. Microscopic algal borings are present in six of eight corals for which thin sections were examined. Solitary corals from localities 19a to e were abraded before final burial (PI. 10, fig. 24). The length-frequency distribution of specimens from these localities suggests that they were transported from elsewhere, as previously discussed for G. canadensis under “‘Cincinnati Arch Region”’ (Text-fig. 7). Their diameters are similar to specimens from Drummond Island and the northwestern and eastern Cincinnati Arch region (Text-fig. 8). The distribution of the num- ber of major septa at a particular diameter for localities 19a, c, and d corresponds to that for corals from “Liberty” strata in the Cincinnati Arch region (Text- figs. 10, 20). The frequency distribution of values on the axial region comparative scale for the few available specimens has peaks at 35 and 65, as does the distri- bution for the ‘‘Whitewater-Elkhorn’’ in the Cincin- nati Arch region (Table 2; Text-fig. 12). Large specimens of G. canadensis that generally show little evidence of abrasion have been collected in Meaford beds to the east of localities 19a to e at Manitowaning (locality M6la; GSC 8530, 8530a, e-/), Clay Cliffs (GSC 8528, 8528a-d; GSC 8529b, c; GSC 8573a-c), and Cape Smith (GSC 1982, 1982a-¢, i+) on Manitoulin Island (PI. 10, figs. 18, 19; see Text-fig. 18 for locations). They are thought to represent a pop- ulation that did not undergo extensive transport. The distribution of the number of major septa at a partic- ular diameter is similar to that for specimens from ‘Waynesville’ strata in the Cincinnati Arch region (Text-figs. 10, 20), suggesting that these corals may have lived in slightly deeper water than those found elsewhere in the Meaford beds or in the uppermost Wekwemikongsing beds. Except for a single, small, abraded specimen of Grewingkia rustica (Billings, 1858a) found in basal Meaford beds at locality 19b (Pl. 11, fig. 24), this species is known only from Lake St. John, Québec. The Manitoulin Island specimen may have been trans- ported from the east. Corals of Streptelasma divari- cans (Nicholson, 1875b) that are attached to bryozo- ans are rare near the base of the Meaford beds at locality M6la (PI. 3, figs. 16, 17s, 18s). The absence of this species in Meaford beds to the west may indi- cate that favorable substrates were seldom stabilized during periods of non-deposition. Copper and Grawbarger (1978) studied the paleo- ecologic succession leading to a lower Meaford bio- strome on eastern Manitoulin Island. Solitary corals were not observed in the ‘level bottom’’ community occupying a muddy substrate, but were reported in the ‘“‘wave baffle margin’’, ‘‘protected subtidal’’, and biostromal “‘wave baffle’? communities where carbon- ate sediments were deposited. Overlying the Meaford beds, the Kagawong beds of the upper member of the Georgian Bay Formation consist of about 30 m of generally massive dolomite, dolomitic limestone, and limestone. Burrowed strata and branching bryozoan beds are present. Cross-bed- ding, fine planar laminae, and gastropod-pelecypod beds are less common. Stromatoporoid—colonial coral biostromes occur near the base and top of the unit. Streptelasma divaricans is rare, and was found at only two of 15 Kagawong exposures that were examined. At locality 19f, in the middle of the unit, the species is rare to uncommon in association with branching bryozoans and brachiopods. One coral was attached to a pelecypod. The lithology, fauna, and structures such as burrows and fine planar laminae suggest that the Kagawong beds were deposited in a periodically semi-restricted, shallow marine environment, perhaps occasionally behind colonial coral—stromatoporoid banks. Cross-bedded strata indicate periods of higher energy conditions. The association of brachiopods, bryozoans, and rare solitary corals in the middle of the unit suggests that more normal marine conditions existed during mid-Kagawong deposition. Foerste (1916, p. 104; 1924, p. 52) and Caley (1936, p. 43) considered the Kagawong beds to be equivalent to the Saluda or *‘Whitewater”’ of the Cincinnati Arch region on the basis of fauna and lithology. The stratigraphic position at the top of the Richmond Group suggests correlation with the *‘Whitewater-Elkhorn’’. Meaford, Ontario Fritz (1926) described the Ordovician stratigraphy and paleontology in the vicinity of Meaford (Text-fig. 2, area No. 8; Text-fig. 18). Richmondian strata are presently included in the Georgian Bay Formation and overlying Queenston Formation (Liberty, 1969, pp. 73-83). Foerste (1916, pp. 129, 130) listed solitary cor- als, together with stromatoporoids and the colonial 34 BULLETIN 314 corals Tetradium, Columnaria (?=Favistina), and Ca- lapoecia from the richly fossiliferous limestone and shale (Vincent Member of Fritz, 1926, pp. 93, 94; up- per Georgian Bay Formation of Liberty, 1969, pp. 73-79) immediately beneath the Queenston Formation red shales. A transverse section of one of his speci- mens (GSC 8531) shows it to be Grewingkia canaden- sis (Billings, 1862). Epizoic and boring bryozoans have been observed on solitary Rugosa in Foerste’s collec- tion (GSC 853la and 8531b, respectively). Another specimen (ROM 12325) is associated with bryozoans and brachiopods in calcarenite. Foerste (1916) consid- ered these strata to be ‘“‘Waynesville”’ in age, but their position in the stratigraphic sequence and the presence of solitary and colonial corals suggest they may be equivalent to the *‘Liberty-Whitewater’’ in the Cincin- nati Arch region. Czurda, Winder, and Quigley (1973, p. 1803) concluded that detrital quartz and heavy min- erals within the Georgian Bay Formation were derived from the Canadian Shield to the north, suggesting that it was positive. The Queenston delta prograded over the Richmond Group lithology (Georgian Bay For- mation) in this area. The Queenston Formation may correlate with the ‘**Whitewater-Elkhorn’’, as suggest- ed by its stratigraphic position. Liberty (1969, p. 81) noted a strong paleontological correlation of the Queenston with the highest ‘*‘Whitewater’’ and Salu- da. On Bruce Peninsula northwest of Meaford, several colonial coral biostromes occur within the Queenston Formation (Liberty and Bolton, 1971, pp. 25-28). These are thought to correlate with the Kagawong beds of Manitoulin Island. Liberty and Bolton (1971, p. 126) listed solitary corals from several localities. Streetsville, Ontario Dyer (1925a, 1925b) described the Ordovician stra- tigraphy and paleontology in the vicinity of Streets- ville, near Toronto (Text-fig. 2, area No. 9; Text-fig. 18). Richmondian strata are presently included in the Georgian Bay Formation and overlying Queenston Formation (Liberty, 1969, pp. 73-83). Foerste (1916, p. 133) reported rare, very small solitary corals in a local incursion of Richmond Group limestone and shale (Columnaria reef, Meadowvale Member of Dyer, 1925b, p. 125; upper Georgian Bay Formation of Liberty, 1969, pp. 73-79) ‘‘a short distance” (Foerste, 1916, p. 133) beneath the Queenston For- mation red shales. A small, poorly preserved specimen with dilated septa (ROM 335HR) is herein referred to as Grewingkia? sp. If these small corals are G. can- adensis, they may represent the smallest size fraction that was transported farthest toward shore from an initial population (see discussion for G. canadensis under *‘Cincinnati Arch Region’’). Foerste also re- ported specimens of the colonial coral Calapoecia, as well as bryozoans and gastropods. He stated that the fauna suggested *‘Whitewater’’ affinities to E. O. UI- rich. Dyer (1925b, p. 125) suggested correlation with the Saluda or “‘Whitewater’’ in the Cincinnati Arch region. On the basis of stratigraphic position, these strata may be equivalent to the “‘Liberty’’, with the ‘‘Whitewater-Elkhorn’’ represented by the Queens- ton Formation. Czurda, Winder, and Quigley (1973, p. 1803) suggested that detrital quartz and heavy min- erals within the Georgian Bay Formation in this area were derived from the Taconic Mountains to the east. Montréal, Québec Richmondian stratigraphy in the vicinity of Mon- tréal (Text-fig. 2, area No. 10; Text-fig. 18) has been summarized by Clark and Stearn (1963, p. 40). The 48 m thick Pontgrave River Formation comprises calcar- eous marine shale and limestone. The overlying Be- cancour River Formation is more than 600 m thick, and consists of the basal 15 m thick Carmel River Member, a non-marine gray shale, overlain by red and green non-marine shale and sandstone of the Queens- ton facies. Foerste (1916, pp. 153, 155) reported solitary corals from fossiliferous *‘Waynesville’’ beds (Pontgraveé River Formation) beneath the Queenston red shales (Bécancour River Formation) at St. Hilaire and St. Hugues. At St. Hilaire, brachiopods, pelecypods, and gastropods were also listed. The corals are associated with brachiopods at St. Hugues, where they occur in glacial erratics that probably came from a nearby source. Foerste (1916, p. 145) found one solitary coral as well as brachiopods in a sequence termed ““Waynesville’’ (Pontgrave River Formation) at the Nicolet River section. Richmondian solitary corals from the vicinity of Montréal were assigned to Strep- telasma rusticum by Foerste, but their identity is un- certain because specimens have not been located for sectioning. Lake St. John, Québec At Snake Island, Lake St. John (Text-fig. 2, area No. 11; Text-fig. 18) solitary rugose corals are ‘‘thrown up in great numbers by the waves from some [limestone] stratum below water-level’ (Foerste, 1924, p. 65). Foerste (1916, pp. 156-158) listed the fauna, including solitary corals, the typical Richmond Group colonial genera Columnaria (?=Favistina), Ca- lapoecia, Lyopora, and Tetradium, and stromatop- oroids, from in situ strata at water level. ORDOVICIAN RUGOSE CORALS: ELIAS 35 Grewingkia rustica (Billings, 1858a) is the only sol- itary coral known from Lake St. John. The species is externally very similar to G. canadensis, being cera- toid to trochoid and straight to slightly curved in early and intermediate stages, and cylindrical in later stages (Pl. 11, figs. 16, 20). The specimens are water-worn, but this abrasion may be at least partly of recent ori- gin. Epizoic bryozoans occur on five of 18 corals. Four of the bryozoans are on the counter side of their host, three on an alar side, and four on the cardinal side. Borings assigned to Trypanites weisei are present in seven of 18 specimens, and most are located on the cardinal side. The microscopic algal borings present in all five corals for which thin sections were examined may be Ordovician and (or) Holocene in age (PI. 11, fig. 29). They are generally very fine, and appear to differ from those of the Cincinnati Arch region. Foerste (1916, p. 156) provisionally correlated these strata at Lake St. John with the *‘Whitewater’’. MAQUOKETA GROUP Introduction The Maquoketa Group (Text-fig. 2) is Edenian through Richmondian in age (Templeton and Willman, 1963, pp. 130, 131). The source area of this marine clastic wedge was to the east, and the unit rapidly thins from nearly 300 m in eastern Indiana (including the Richmond Group at the top) to about 60 m in west- ern Indiana (Gray, 1972, pp. 1, 4), Illinois (Willman and Buschbach, 1975, p. 82), and Iowa (Ladd, 1929, p. 331) (see Gutstadt, 1958, figs. 7-9). In Indiana, Gray (1972, fig. 4) recognized deep basin sediments in the southwest and shelf deposits to the north and east. The Maquoketa Group is predominantly gray shale. The Neda Formation occurs locally at the top of the group in Iowa (Agnew, 1955, p. 1717), Wisconsin, northern Illinois (Willman and Buschbach, 1975, p. 86), and possibly northeastern Indiana (Gray, 1972, p. 19). It is generally less than 3 m thick, and consists of red shale interbedded with odlitic hematite. A few Maquoketa species were reported from the formation by Savage and Ross (1916). The Neda is thought to be a western tongue of the Queenston delta (Willman and Buschbach, 1975, p. 86). Only the Edenian through Maysvillian Scales Formation is present in southeast- ern Minnesota. Bayer (1965, p. 45) indicated that clas- tic material in the Elgin Member of this formation probably marks the western edge of detritus shed from the Taconic Mountains, while sand in the overlying Clermont Member carbonates was derived from an uplift of the Transcontinental Arch to the west (Bayer, 1965, p. 44; Austin, 1972, p. 470). The remainder of the Cincinnatian sequence in Minnesota was eroded prior to deposition of the overlying Devonian unit (Austin, 1972, p. 470). Upper Ordovician strata be- come thinner and the terrigenous sand and carbonate content in the Maquoketa Group increases toward the Ozark Dome, which was probably slightly positive, as seen in the vicinity of Thebes, southern Illinois (Tem- pleton and Willman, 1963, p. 131; Bayer, 1965, p. 45). The Maquoketa is termed Sylvan Shale in Oklahoma (Ladd, 1929, pp. 311, 407; Templeton and Willman, 1963, p. 192). Northeastern lowa The stratigraphy and fauna of the Maquoketa Group in northeastern Iowa (Text-fig. 2, area No. 12; Text- fig. 18) have been described by Savage (1905), Calvin (1906), and Ladd (1929). The lowermost Richmondian unit is the Clermont Member of the Scales Formation. This gray shale contains a fauna dominated by bra- chiopods. Ladd (1929, p. 391) listed a solitary coral from the Clermont Member, and described and figured a specimen possibly from the Clermont that he as- signed to Streptelasma haysii (Meek, 1865) (Ladd, 1929, p. 397, pl. 4, figs. 1, 2). This specimen (SUI 2-050) has not been located, and so its identity remains uncertain. Another coral probably from the same unit is herein assigned to Helicelasma randi Elias (1981). The overlying Fort Atkinson Formation consists of dolomite and limestone containing brachiopods and echinoderm fragments. Bighornia cf. B. patella (A. E. Wilson, 1926) occurs in this unit. One of the three known specimens has borings assigned to Trypanites weisei (Pl. 14, fig. 23). The Brainard Formation over- lies the Fort Atkinson, and consists of gray shale with some limestone beds at the bottom and top. It contains bryozoans and brachiopods. One specimen of Heli- celasma randi is known from the top of the formation in Clayton County, at the southern extremity of this area. The septal grooves and interseptal ridges are pre- served, indicating little abrasion prior to burial. Sav- age (1905, p. 487) listed solitary corals throughout the Maquoketa Group in Fayette County. Templeton and Willman (1963, pp. 132, 133) consid- ered the Clermont Member similar in lithology and stratigraphic position to the ““Arnheim”’ of the Rich- mond Group in the Cincinnati Arch region. They noted that the Fort Atkinson Formation and **Waynesville”’ are remarkably similar in fauna, lithology, and strati- graphic position. The Brainard Formation was corre- lated with the *‘Liberty-Whitewater-Elkhorn”’ primar- ily on the basis of lithology. Faunal correlation of the Brainard Formation and its uppermost Cornulites zone with the “‘Elkhorn”’ was considered highly prob- able by Ladd (1929, pp. 369, 370). 36 BULLETIN 314 Southeastern Iowa and Northwestern Illinois In southeastern Iowa and northwestern Illinois (Text-fig. 2, area No. 13; Text-fig. 18), the Maquoketa Group is predominantly gray shale, much of it unfos- siliferous (Ladd, 1929, p. 330; Savage, 1925, pp. 240-245; Willman and Buschbach, 1975, p. 86). Near the top, fossiliferous limestone interbeds with bra- chiopods and bryozoans are present. Ladd (1929, pp. 371, 391-395) termed this the Cornulites zone and list- ed the fauna. Votaw and Kolata (1981) recognized the Scales Shale, Fort Atkinson Limestone, and Brainard Shale within the Maquoketa Group in northern Illi- nois. They assigned the latter two units to conodont Fauna 12 (Sweet, Ethington, and Barnes, 1971), indi- cating a late Maysvillian—Richmondian age for the up- per Maquoketa. The solitary coral Helicelasma randi Elias (1981) occurs in argillaceous limestone beds in the upper Brainard at Sterling, Illinois, where strati- graphic sections were described and the fauna was listed by Savage (1925, pp. 240-245). The septal grooves and interseptal ridges are generally preserved, indicating little abrasion prior to burial (Pl. 6, figs. 1, 2, 5). Of the epizoic bryozoans observed on eight cor- als, six are on the counter side, seven on an alar side, and three are on the cardinal side (Pl. 6, fig. 2). Ladd (1929, p. 391) listed a solitary coral from the Cornulites zone in southeastern Iowa, and Savage (1925, p. 244) listed them as rare in fossiliferous limestone beds of the upper Maquoketa Group near Preston, Iowa. Thebes, Illinois In the vicinity of Thebes (Text-fig. 2, area No. 14; Text-fig. 18), the Maquoketa Group comprises the Thebes and Orchard Creek Members of the Scales Formation. The Maquoketa is overlain by the Gi- rardeau Formation (Willman and Buschbach, 1975, pp. 86, 87, fig. O-27). The Thebes Member has a max- imum thickness of 48 m, and consists of silty, fine- grained sandstone in medium to thick beds and local cross-beds. Trace fossils occur in the upper part of the member. It grades or intertongues eastward and north- ward into shales of the lower Elgin Member. The over- lying Orchard Creek Member is 3 to 9 m thick and is predominantly gray shale. It may be equivalent to the Elgin Member, but could be as young as the Brainard Formation (Willman and Buschbach, 1975, p. 86). Ko- lata and Guensburg (1979, p. 1122) suggested a Rich- mondian age on the basis of crinoids. The Orchard Creek fauna, including brachiopods, molluscs, and tri- lobites, occurs in calcareous layers, and was listed and described by Savage (1917b, pp. 263, 264). Pryor and Ross (1962, p. 9) listed a graptolite, and Kolata and Guensburg (1979) described a ‘‘carpoid’’. Solitary cor- als are rare. Only two specimens of Helicelasma randi Elias (1981) have been collected from the Orchard Creek (Mississippi River section of Pryor and Ross, 1962, fig. 3; section B of Satterfield, 1971, fig. 1; lo- cality 1 of Kolata and Guensburg, 1979, fig. 1). The member grades upward into the Girardeau Formation, which is up to about 9 m thick (Satterfield, 1971, p. 266). It consists of unevenly-bedded, fine-grained to lithographic limestone with shale partings and sili- ceous interbeds and nodules. The Girardeau may be equivalent to the Fort Atkinson Formation, but an age as young as or younger than the Brainard is presently favored (Willman and Buschbach, 1975, p. 87). The fauna, including echinoderms, bryozoans, brachio- pods, molluscs, and trilobites, was described by Sav- age (1917a). Conodonts of the Girardeau indicate a very late Ordovician age (Satterfield, 1971). Brower (1973, p. 265) suggested a Richmondian or younger (Gamachian) age for the crinoids. UPPERMOST ORDOVICIAN OF OKLAHOMA, MissouRI AND ILLINOIS Introduction Thompson and Satterfield (1975) revised the stratig- raphy and studied conodonts contiguous to the Or- dovician-Silurian boundary in eastern Missouri (Text- fig. 2, area No. 16, 17). Their work indicated that strata previously included at the base of the Lower Silurian Edgewood Group of the Alexandrian Series (Savage, 1908, 1917a) are Late Ordovician in age. These strata comprise the Noix Limestone and Cyrene Formation in Pike County, northeastern Missouri, and the Lee- mon Formation in Cape Girardeau County to the southeast (Text-fig. 21). The Noix Limestone lies dis- conformably above the Maquoketa Group and is dis- conformably overlain by a Lower Silurian sequence (Thompson and Satterfield, 1975, pp. 89, 103). While the Noix was being deposited, Cyrene strata formed immediately to the west. Deposition of the Leemon Formation on an eroded Maquoketa Group—Girardeau Formation surface was followed by a period of erosion preceding Early Silurian sedimentation (Thompson and Satterfield, 1975, p. 101). A late Ashgill age for the Noix Limestone and Leemon Formation was sup- ported by Amsden’s (1974) study of the brachiopods. Further conodont work has suggested that the Noix is Richmondian or younger Ordovician (McCracken, Barnes, and Kennedy, 1980; McCracken and Barnes, 1981, p. 72). The Keel Formation at the base of the Chimneyhill Subgroup in the Arbuckle Mountains of Oklahoma (Text-fig. 2, area No. 15; Text-fig. 21) had been cor- related with the Edgewood Group of Missouri, and areinBaiqns ewsejajdang > + ss 5 s+ + 2 2 aa a in E ° 1QW oSpPiig 1aqwaw 4aZIBMYyIS NOLLWWHOS IW173HTI 33 Mv yNYy NOLLVWHO4 agoom13 NOILVWHOS W113 M Xu S SS > = sqQW 157 = sabuassiy BLINO100) wy gony 5 N33x9. 3NOLS3WI1 XION 5 ONITMOs! LNVANS dNOwD goomM39q03 MISSOURI auejnbaiqns innan , Bowling Green® * 22 < pe 5 #5 face = =x ° 311WO100 waau9 oNIMog] NOlLvWHO4 AN3YAD dnouws qoom39qaa3 \ aieinBaigns ewseaidang = 31VHS VL3xONOVN 31VHS VL 3 xONOVW 31VHS VLSNONOVN 3NOLS3IWIT w33y9 NOLX3S NOILVWHOS NOW337 a soys wnj\jAydopog ds § ‘!asuauoWaa) eWSejajdas ine 3IVHS 43349 QYVHOYO fe} 3JIVHS AJNOLS3WI1 43349 NOLX3S NOILVWHOS NOW331 4 CMP Wanso 6o000 005 OG SNO1S3WI1 ANVYHIDOD NOILVWHOF NVIHOVWV9¢ NVIYNTIS Y3MO1 NVIDIAOGHO Yq 43349 QYVHOHO 31VHS NVATAS daddn Will Co. 21b. Clinton Springs Bowling Green 20b. New Wells 20a. Short Farm Arbuckle Mtns. NVIGNOWHOIY Text-figure 21.—Uppermost Ordovician stratigraphic sections (all except Will County to the same scale) and distribution of solitary rugose corals in Oklahoma, Missouri, and Illinois (see ‘Appendix: Collecting Localities”, for further information). For explanations of symbols see legends in Text-figure 3. 38 BULLETIN 314 was therefore placed in the Lower Silurian Alexan- drian Series (Maxwell, 1936). It unconformably over- lies the Sylvan Shale and is overlain, usually uncon- formably, by Silurian strata (Maxwell, 1936, p. 48; Amsden, 1974, p. 25). Amsden (1974, p. 26) found that all Keel Formation brachiopods occur in the Noix Limestone and many are present in the Leemon For- mation. He therefore tentatively correlated these three units, thereby assigning the Keel Formation to the up- per Ashgill Series. Savage (1910) recognized the Alexandrian Series in northeast Illinois (Text-fig. 2, area No. 18), and named these strata the Channahon Limestone. He considered the fauna most closely related to the Edgewood of Missouri. Willman (1973, pp. 12-14) proposed the Wilhelmi Formation, which includes the Channahon Limestone, for sediments deposited in channels erod- ed in the underlying Neda Formation and Brainard Formation of the Maquoketa Group (Text-fig. 21). These deposits are herein correlated with the Cyrene and Leemon Formations of Missouri, as will be dis- cussed under *‘Will County, Illinois’’. Amsden (1974, p. 26) noted that the Keel-Edgewood brachiopods have little in common with North Amer- ican forms, and the assemblage most closely resem- bles the Hirnantia fauna that occurs in the uppermost Ordovician Hirnantian Stage of the European Ashgill Series (Ingham and Wright, 1970; Text-fig. 1). This characteristic brachiopod-dominated fauna has been widely recognized in Great Britain, Scandinavia, northwestern Europe, northern Africa, Kazakhstan, and Burma (Wright, 1968; Lespérance, 1974). In North America, it may be present in siltstones near Ashland in Aroostook County, Maine (R. B. Neuman, 1968, p. 44: Ingham and Wright, 1970, p. 240; Lespeérance, 1974, p. 14). Typical north European representatives occur in mudstone in the Perce area of Québec (Les- pérance, 1974; Lespérance and Sheehan, 1976), and in quartz-bearing limestone on Anticosti Island, Qué- bec (Cocks and Copper, 1981). Amsden (1974, p. 28) believed that the Keel-Edgewood brachiopod species were different from those of the Hirnantia fauna. He noted that the generic assemblages have similarities, but many genera of the Hirnantia fauna are not pres- ent in the Keel-Edgewood, and vice versa. However, as Amsden pointed out, the Keel-Edgewood fauna oc- curs in a carbonate facies, whereas the Hirnantia fau- na is almost everywhere in mudstone. Amsden viewed the Hirnantian aspect of the Keel-Edgewood with cau- tion because most genera common to the two units apparently have considerable ranges in the Late Or- dovician—Early Silurian. Lesperance and Sheehan (1976, pp. 719, 720) stated that the Edgewood could contain a latest Ordovician endemic assemblage de- rived from the Hirnantia fauna and other North Eu- ropean Province species, but considered more likely that it is Silurian with a few hold-overs from the Late Ordovician North American Province. With the strati- graphic revision and conodont biostratigraphy of Thompson and Satterfield (1975), the further conodont studies of McCracken, Barnes, and Kennedy (1980) and McCracken and Barnes (1981, p. 72), and the Or- dovician aspect of the Keel-Edgewood brachiopod fauna, evidence points to a latest Ordovician age for the carbonate sequence of Oklahoma, Missouri, and Illinois. If the upper Maquoketa Group is equivalent to the ‘Elkhorn’ of the Richmond Group, as discussed pre- viously under “‘Northeastern Iowa’’, it was deposited during latest Richmondian time. The uppermost Or- dovician carbonate sequence in Oklahoma, Missouri, and Illinois unconformably overlies the Maquoketa, suggesting a post-Richmondian age. There is no evi- dence for comparable deposition above the Richmond Group in the Cincinnati Arch region, which is uncon- formably overlain by the middle Llandovery (Lower Silurian) Brassfield Formation. The Brassfield has been correlated with the Kankakee Formation of northeastern Illinois, the Sexton Creek Limestone of southwestern Illinois and southeastern Missouri (Will- man and Atherton, 1975, p. 99), and the Cochrane Limestone of Oklahoma (Maxwell, 1936, fig. 4) (see Text-fig. 21). Latest Ordovician and earliest Silurian carbonate sedimentation above the Maquoketa Group probably occurred during the interval between depo- sition of the Richmond Group and Brassfield Forma- tion. Schuchert and Twenhofel (1910, pp. 700, 701) established the Gamachian Stage to include the Ellis Bay Formation of Anticosti Island, Québec, and all American Ordovician strata later in age than the youngest Richmondian of Ohio and Indiana. Fauna 13 has been proposed for the lower Ellis Bay conodont assemblage, and is considered Gamachian (Mc- Cracken and Barnes, 1981, p. 64). Conodonts in the Noix Limestone indicate a Richmondian or younger Ordovician age, but they cannot be equated with those in the Ellis Bay (McCracken and Barnes, 1981, p. 72). The solitary coral Streptelasma subregulare (Savage, 1913) occurs in the Leemon, Cyrene, Wilhelmi, and possibly Keel Formations. It is similar to many spec- imens of S. affine (Billings, 1865), which is common in the Ellis Bay Formation, and most closely resem- bles S. unicum B. Neuman (1975), probably from the Hirnantian of Sweden. The Keel Formation of Okla- homa, the Leemon, Noix, and Cyrene Formations of Missouri, and the Wilhelmi Formation of Illinois are ORDOVICIAN RUGOSE CORALS: ELIAS 39 herein tentatively considered to have been deposited during the Gamachian. Brachiopods suggest that these units may be equivalent to the Hirnantian Stage of Europe. On Anticosti Island, brachiopods indicate that the Hirnantian is equivalent to the upper part of the Gamachian (Cocks and Copper, 1981). Uppermost Ordovician strata in Oklahoma, Mis- souri, and Illinois represent the initial transgression of a shallow epicontinental sea in which the Middle Pa- leozoic carbonate sequence of east-central North America was deposited (Amsden, 1974, p. 29). The timing of this transgression probably coincides with the latest Hirnantian transgression recognized in northwestern Europe (Brenchley and Newall, 1980, fig. 22), and suggests that deglaciation began in the latest Ordovician rather than during the Early Silurian as suggested by Berry and Boucot (1973). The pre- dominance of o6litic and bioclastic limestones in Okla- homa, Missouri, and Illinois and the development of bioherms in Missouri indicate fairly high energy, shal- low, normal marine conditions. The presence of ter- rigenous sand in southeastern Missouri suggests that the Ozark Dome may have been slightly positive at this time. Arbuckle Mountains, Oklahoma In the Arbuckle Mountains (Text-fig. 2, area No. 15; Text-fig. 21), the Keel Formation has a maximum thickness of about 4.5 m and comprises the lower Ideal Quarry Member (Hawkins Limestone of Maxwell, 1936, pp. 45-49) and an upper o6litic unit (Keel Lime- stone of Maxwell, 1936, pp. 50-54) (see Amsden, 1974, p. 25). The Ideal Quarry Member is only locally pres- ent and consists of thinly-bedded argillaceous lime- stone. Crinoid stems are common on bedding planes, but other fossils are rare. Maxwell (1936, table 1) listed solitary and colonial corals, a bryozoan, brachiopods, pelecypods, and a gastropod. This member grades up- ward into thickly-bedded o6litic limestone. Fossils are rare in the oolite, from which Maxwell (1936, table 2) listed solitary and colonial corals, brachiopods, and gastropods. Excluding crinoid fragments, brachiopods are the most abundant and diverse megafossils in the Keel Formation (Amsden, 1974, p. 26). Maxwell reported Zaphrentis subregularis Savage (1913) (=Streptelasma subregulare) from the Ideal Quarry Member and Streptelasma sp. from the odlite. The identity of these solitary corals is uncertain because specimens have not been located for sectioning. Cape Girardeau County, Missouri The Leemon Formation of southeastern Missouri is up to 7 m thick. At the type section in Cape Girardeau County (Text-fig. 2, area No. 16; Text-fig. 21, locality 20a), the lower cross-bedded o6lite with Girardeau- type limestone pebbles and fine quartz grains is over- lain by thickly-bedded, bioclastic and partly odlitic calcarenite (Thompson and Satterfield, 1975, pp. 76, 77; Amsden, 1974, p. 19). Except for abundant echi- noderm debris, brachiopods dominate the megafauna. Solitary and colonial corals and gastropods are rare. The following solitary Rugosa are present in the upper part of the Leemon Formation at the type section: Streptelasma leemonense n. sp., Streptelasma sp., and Bodophyllum shorti n. sp. All corals were abraded and some were broken prior to burial (Pl. 4, figs. 1, 2, 4-6; Pl. 13, fig. 14). The only known specimen of B. shorti has a base of attachment on the cardinal side, and was epizoic on a bryozoan (PI. 13, fig. 10). The Leemon Formation is also exposed to the north at locality 20b (Thompson and Satterfield, 1975, pp. 79, 80; Amsden, 1974, pp. 21, 22; Text-fig. 21). Here, basal biohermal limestone mounds are up to 0.5 m high, with calcareous shale between and overlapping them. The mounds contain odids (PI. 4, figs. 11, 14, 15), glauconite, phosphatic material, quartz grains, and fossils in a calcareous matrix. The most abundant fossils are branching bryozoans, apparently preserved in life position. Some brachiopods are attached to and partly overgrown by bryozoans. Amsden (1974, p. 22) considered this brachiopod fauna the most character- istic Late Ordovician assemblage in the uppermost Ordovician sequences of Oklahoma and Missouri. Sol- itary Rugosa assigned to Streptelasma subregulare (Savage, 1913) are abundant at the base of some mounds. Specimens are randomly oriented and gen- erally lie horizontally on an alar side, but calices of a small proportion face “‘down”’ or “‘up’’. Although these corals have moderately dilated septa in early stages, they were apparently quite fragile because of the very narrow stereozone, open axial region, and very widely spaced tabulae (PI. 4, figs. 9-22). Tips of many specimens were broken off and calice rims of some were broken before burial (Pl. 4, figs. 14, 15). However, all these corals have growth lines pre- served, indicating no abrasion (PI. 4, figs. 10, 11, 14, 15, 19). They may have been knocked over and buried suddenly, perhaps during a storm. The presence of S. subregulare at the base of the mounds suggests it may have been the initial species to colonize the eroded surface of the Orchard Creek Shale. The corals are not associated with and did not form a framework structure, and were not hosts of epizoic or boring or- ganisms. 40 BULLETIN 314 Pike County, Missouri The Noix Limestone is exposed in eastern Pike County (Text-fig. 2, area No. 17). It is massive and cross-bedded, and consists of odids in a micritic ma- trix. Glauconite and phosphatic grains are present in the lower part (Thompson and Satterfield, 1975, pp. 85-93: Amsden, 1974, pp. 8, 9). At the type section (Text-fig. 21, locality 21h), Thompson and Satterfield (1975, fig. 12) placed their bed 9, bounded by shale interbeds at its base and top, in the 2 m thick Noix Limestone. It did not yield conodonts, and was pre- sumably included because it contains odids. Solitary corals of the same species that is abundant at the base of their bed 10 (Kissenger Limestone Member of the Silurian Bryant Knob Formation) are present in bed 9, which is herein placed at the base of the Kissenger Member. The odids were probably reworked from the Noix Limestone. The Noix fauna in Pike County has been listed by Rowley (1908, p. 23), and by Savage (1917a, pp. 82, 83), who also described new species. Rubey (1952, p. 170) listed the fauna in adjacent Cal- houn County, Illinois. Echinoderm debris is generally abundant. Brachiopods dominate the remainder of the megafauna, with bryozoans, trilobites, gastropods, pelecypods, corals, and tentaculitids making up a small fraction of the assemblage (Amsden, 1974, p. 12). Although solitary corals have been listed from the Noix Limestone, none were found at localities 21a and 21b (Text-fig. 21). To the west of the Noix Limestone belt, the Cyrene Formation is present in the vicinity of Edgewood, Cy- rene, and Bowling Green in Pike County (Thompson and Satterfield, 1975, pp. 93-97, fig. 11). It is about 2 m thick at Bowling Green and consists of fine- to me- dium-grained, fossiliferous, dolomitic limestone (Text- fig. 21). The Cyrene fauna near Edgewood was listed by Savage (1917a, pp. 82, 83), who considered it very similar to that of the Noix Limestone. Conodonts of the Cyrene also occur in the Maquoketa Shale (Thompson and Satterfield, 1975, p. 96). Thompson and Satterfield (1975, p. 103) concluded that Cyrene strata were being deposited in the west while the Noix Limestone formed to the east. The solitary coral Streptelasma subregulare (Savage, 1913) is present in the Cyrene Formation. On the basis of this occur- rence, the Cyrene is correlated with the Leemon For- mation at locality 20b in southeastern Missouri. Will County, Illinois Savage (1910) discussed the Channahon Limestone in Will County (Text-fig. 2, area No. 18) and listed and described the fauna, which is dominated by brachio- pods (Savage, 1917a, pp. 84-86). The Wilhelmi For- mation of Willman (1973, pp. 12-14), which includes the Channahon, is up to 30 m thick in some channels but is absent or very thin between them. This forma- tion comprises the very argillaceous dolomite and do- lomitic shale of the Schweizer Member and the argil- laceous dolomite of the overlying Birds Member (Text-fig. 21). A few thin, fossiliferous beds occur in the Schweizer Member, and some of the purer beds in the Birds Member are fossiliferous. C. A. Ross (1962) described graptolites suggesting an early Llan- dovery (Early Silurian) age from 0.5 m below the low- est occurrence of a shelly fauna in the Wilhelmi For- mation. The solitary coral Streptelasma subregulare (Savage, 1913), collected by Savage from the Chan- nahon Limestone, occurs with this shelly fauna. Its presence indicates correlation of the Wilhelmi with the Cyrene Formation of northeastern Missouri and the Leemon Formation at locality 20b in southeastern Missouri. The Wilhelmi Formation is herein consid- ered latest Ordovician in age. The overlying Elwood Formation is cherty (Willman, 1973, pp. 14, 15), as is the Lower Silurian Sexton Creek Limestone of south- eastern Missouri and southern Illinois. Silicified corals are common in the Elwood, and in the Lower Silurian Bryant Knob Formation of northeastern Missouri, and the basal Brassfield Formation near Gallatin, Tennes- see. CONTINENTAL MARGIN Introduction More than 1000 m of highly variable clastic rocks of Ashgill age that were deposited north of the Taconic Mountains at the continental margin of North America are exposed in northern Maine (Text-fig. 2, area No. 19, 20). The sequence indicates rapidly changing local tectonic controls (R. B. Neuman, 1968, p. 45). These clastic rocks grade northward into carbonates. The calcareous strata of the White Head Formation on the Gaspé Peninsula of Québec (Text-fig. 2, area No. 21) are Ashgill (Late Ordovician) and Llandovery (Early Silurian) in age. This sequence represents deposition in a more stable environment through a long period of time (R. B. Neuman, 1968, p. 45). On Anticosti Island, Québec (Text-fig. 2, area No. 22), the Upper Ordovi- cian is more than 1000 m thick at some locations, and consists of interbedded limestones and shales of the Vauréal Formation and overlying Ellis Bay Forma- tion. Twenhofel (1928, pp. 18-21) considered the li- thology, sedimentary structures, and fauna to indicate a shallow marine environment, and believed the clastic sediments were derived from the north. Nowlan and Barnes (1981, p. 3) concluded that the lower Vauréal was deposited in relatively unstable, deep subtidal ORDOVICIAN RUGOSE CORALS: ELIAS 4] conditions, and the upper Vaureéal in progressively shallower subtidal environments. Within the Ellis Bay Formation, McCracken and Barnes (1981, p. 66) rec- ognized a lateral transition from near-shore deposits in the east to offshore, shallow subtidal in the west. The general upward increase in carbonate content and faunal diversity and abundance, and the presence of stromatoporoid—colonial coral bioherms toward the top of the Anticosti sequence indicate a general shal- lowing-upward trend accompanied by increased pro- ductivity. This is also suggested by the frequency of microscopic algal borings observed in thin sections of solitary corals. These borings are present in 16 percent of 19 specimens from the Vauréal Formation, and 45 percent of 40 from the overlying Ellis Bay Formation. Sedimentary cycles in the upper portion of the gen- erally regressive sequence on Anticosti Island have been attributed to eustatic sea-level fluctuations ac- companying Late Ordovician glaciation (Petryk, 1981b). The greater thickness of continental margin marine deposits compared with those in the epiconti- nental sea (Richmond and Maquoketa Groups) is prob- ably largely the result of more rapid subsidence. Also, sedimentation appears to have been continuous at the continental margin during latest Ordovician time, whereas a period of non-deposition and (or) erosion occurred in the interior. The Hirnantian strata of Gaspe and possibly northern Maine, and the Ellis Bay Formation (Gamachian) of Anticosti Island were de- posited during this interval. Penobscot County, Maine More than 1000 m of Ashgill strata, including large amounts of coarse, bouldery, polymict conglomerate, pebbly siltstone, and other clastic rocks, are present in Penobscot County (R. B. Neuman, 1978, pers. comm.; Text-fig. 2, area No. 19; Text-fig. 22). The age assignment was made on the basis of brachiopods and trilobites. Colonial and solitary corals and gastropods are also present in the sequence (R. B. Neuman, 1968, pp. 44, 45). The assemblage and relatively high diver- sity of genera more closely resemble faunas of Europe than those elsewhere in North America (R. B. Neu- man, 1968, p. 36). Solitary Rugosa in this clastic se- quence are associated with carbonate debris and fossil fragments (Pl. 13, figs. 8, 9). The coral exteriors are generally abraded, but the preservation of septal grooves and interseptal ridges on some suggests that they may have been transported a short distance from a nearby carbonate bank. Kenophyllum? sp. is rare 61 m above the base of the sequence. Solitary corals are more common 520 m above the base, where Strepte- lasma rankini n. sp., Grewingkia penobscotensis n. sp., and Bodophyllum neumani n. sp. occur. Ashland, Maine R. B. Neuman (1963) reported tuffaceous mudstone, basalt-limestone conglomerate, and other clastic rocks in a 45 m thick unnamed unit exposed in a gravel pit 9 km east of Ashland, Maine (Text-fig. 2, area No. 20; Text-fig. 22). Brachiopods of north European affinity are by far the most common fossils in the sequence, followed in abundance by rugose and tabulate corals. Trilobites, gastropods, bryozoans, and graptolites are rare. The strata containing these fossils were depos- ited near the site of contemporaneous volcanism. Sol- itary Rugosa were found in bedrock exposures in the northeastern part of the gravel pit (R. B. Neuman, 1963, fig. 30.2). The abraded, apparently randomly oriented corals occur in mudstone containing abun- dant volcanic fragments. The only species known from this locality, Grewingkia pulchella (Billings, 1865), also occurs in the upper Vauréal and Ellis Bay For- mations (Ashgill) of Anticosti Island, Québec. This in- dicates an Ashgill age for the unit at Ashland, and connection between the clastic and carbonate facies at the eastern continental margin. Percé, Quebec The White Head Formation in the vicinity of Percé (Text-fig. 2, area No. 21) is Ashgill and Llandovery in age (Lesperance, Sheehan, and Skidmore, 1981). Its faunas in general are similar to those of Europe (Schu- chert and Cooper, 1930, p. 170; Cooper and Kindle, 1936, p. 349; Lespeérance, 1968a, p. 812; Sheehan and Lespeérance, 1979, pp. 951, 952). Foerste (1936, p. 373) studied the Ordovician cephalopods, and suggested that they are most closely related to those in the Rich- mondian of the North American continental interior. The affinity of most conodonts is with the Midconti- nent Province, but a few North Atlantic Province taxa are present (Nowlan, 1981, p. 274). F. Martin (1980) described chitinozoan and acritarch species that are also known from the central United States, eastern Canada, and northwestern Europe. The White Head Formation is exposed in a belt that extends about 13 km northwest of the type section at Cap Blanc. The Ordovician portion locally exceeds 400 m in thickness, and has been subdivided into five lithologic units, numbered in ascending order (Skid- more and Lespérance, 1981, pp. 31, 33, figs. 25, 26; Text-fig. 22). The limestones, shales, and sandstones of units 1 to 4 are early to middle Ashgill in age (Les- perance, Sheehan, and Skidmore, 1981, p. 225, fig. 2; 42 BULLETIN 314 Nowlan, 1981, pp. 265, 266, fig. 6). The distribution of fossils in these units has been summarized by Les- perance, Sheehan, and Skidmore (1981, p. 225). Unit 5 consists of calcareous mudstones, and contains the typical brachiopod-dominated Hirnantia fauna (Les- pérance, 1974; Lesperance and Sheehan, 1976, 1981). Most species identified from the Perce area also occur in the Hirnantian Stage of the Ashgill Series in north- ern Europe, and the fauna is most closely related to that of Great Britain and Ireland (Lespérance and Sheehan, 1976, pp. 721, 722). Bolton (1980, p. 18, pl. 2.7, figs. 2, 3) illustrated solitary corals assigned to Lobocorallium trilobatum vaurealense (Twenhofel, 1928) that were collected from unit 4 on Flynn road, 32 m below the base of the Hirnantian. This species is associated with bryozoans and the colonial corals Paleofavosites, Propora, and Catenipora. Correlation with the upper part of the Vauréal Formation on An- ticosti Island is suggested by the presence of L. tri- lobatum vaurealense in both units (see discussion un- der ‘Anticosti Island, Québec’’). Nowlan (1981, p. 266, fig. 6) assigned the conodonts of unit 4 to Fauna 13 (McCracken and Barnes, 1981), indicating corre- lation with the Ellis Bay Formation of Anticosti Is- land. However, Gamachignathus, which characteriz- es the fauna, occurs in the upper Vauréal as well as in the Ellis Bay (Nowlan and Barnes, 1981, p. 5). Sol- itary Rugosa are not known from units | to 3 and 5 of the White Head Formation. In the Percé area, Upper Ordovician sedimentary rocks also occur in fault slices to the north of the belt that is laterally continuous with the type section of the White Head Formation (Skidmore and Lesperance, 1981, fig. 25). These strata have been assigned to the undivided Matapédia Group by Lesperance, Sheehan, and Skidmore (1981, p. 223), but earlier workers in- cluded them in the White Head. At Grande Coupe, the solitary corals Helicelasma selectum (Billings, 1865), Grewingkia sp., Lobocorallium trilobatum vau- realense, and Bodophyllum? sp. are associated with a diverse fauna including the colonial genera Paleo- favosites, Catenipora, Propora, and Calapoecia, as well as bryozoans, gastropods, cephalopods, brachio- pods, and trilobites (Schuchert and Cooper, 1930, p. 169; Cooper and Kindle, 1936, p. 350; Bolton, 1980, pp. 16, 18, pl. 2.4, fig. 4, pl. 2.5, figs. 9, 10). Trilobites are the most abundant fossils, and suggest an early to middle Ashgill age for this Stenopareia fauna (Les- pérance, 1968a, pp. 813, 815, table 1). All the solitary corals were abraded and some were broken prior to final burial (PI. 6, fig. 18). The single specimen of Bo- dophyllum? sp. examined in this study has an area of attachment on the cardinal side, and was epizoic on a brachiopod (PI. 14, figs. 7-9). Borings assigned to Trypanites weisei are common, and are abundant in the cardinal side of a specimen of Grewingkia sp. (USNM 311638). Of 94 borings in three solitary corals, 27 percent are in the counter side, 23 percent in an alar side, and 50 percent in the cardinal side. The fre- quency distribution of bore diameters is shown in Text-figure 9C. The average diameter is smaller than that of borings assigned to 7. weisei in the Richmond Group of the Cincinnati Arch region and the Selkirk Member of the Red River Formation (upper Middle or Upper Ordovician) in southern Manitoba (Text-fig. 9A, B, D). Microscopic algal borings are present in corals from Grande Coupe, but are not well preserved. The presence of L. trilobatum vaurealense in these strata suggests correlation with unit 4 of the White Head Formation, and the upper part of the Vauréal Formation on Anticosti Island. H. selectum is also known from the upper member of the Vaureal, as well as the overlying Ellis Bay Formation (see discussion under *‘Anticosti Island, Québec’’). Bolton (1980, p. 13) reported unidentified solitary corals from siltstones of the Honorat Group in south- western Gaspé Peninsula. Anticosti Island, Québec Stratigraphy The stratigraphic terminology used herein for An- ticosti Island (Text-fig. 2, area No. 22; Text-fig. 22) follows Bolton (1972), unless specific reference is made to the units recognized by Twenhofel (1928). The recent lithostratigraphic revisions of Petryk (1981la) have not been incorporated into this study. Approximately 300 m of the Vauréal Formation is exposed on the northern part of Anticosti Island, and the formation is at least 1000 m thick in a well drilled near the center of the island (Bolton, 1972, pp. 3, 5). The lower member of the Vauréal includes the portion of Twenhofel’s English Head Formation that is ex- posed along the north shore. Outcrops of this member consist of gray shale and interbedded fine-grained to dense limestone plus intraformational limestone con- glomerate. The limestone beds increase in thickness and become more nodular upward. The lower member continues in the subsurface, where the shale content increases downward in the section until a gray shale unit is distinguishable. The upper member of the Vau- real Formation includes, at or near its base, the west- ern exposures and type section of Twenhofel’s English Head Formation. This member is at least 180 m thick, and consists of gray, fine-grained to dense limestone ANTICOST! ISLAND ASHLAND @ e PENOBSCOT CO. MAINE a < = < Wu a z NIVLYSONN NOILISOd o- NMON® NOILISOd LvVH1S e GRAY WACKE, SILTSTON MUDSTONE LIMESTONE Bodophyllum neumani a 4 c s e8 Ba 25 se os Ox row az fe no e @ Kenophyllum? sp VOLCANIC ROCKS eyayoind emBuimaig oO ED a 2c Ec ao Do fot) [S'S 2Y 3s Do 222 20 63 9 = =$ @ E35 E Sap7c =) Got aeE = psz 5 o BS SS © ox > Oo 2% £ TS Te 9 oFo Oo oa =g0 3 © B50 0 +4 r0s4 @ ° Fs z : z i) a z = < < 3 oO (suinn S) ay Qv3H ahh -NVN&IH | TTISHSYV e - o I A ejjayed g 49 elmoybig = esuapeayysibua wnjjAydopog — asuajeainen winyeqoj4y wnije1090qG07 — wnjejnBue wnijyjesooes1ag ee esuasija wnyAydyeg _ .... — eyayoind embuimaiy 2 —_ Winjoajas ewsejaoyayH ........ - - _ suljje Pwisejajdaijg --— —_— — : Hii 1H uw w Ww ~ 1S) (s) c 2|6 = 2|6 n 5 ee) ve i 1 a 1H einer i a (ZZ6L) NO1108 ee) eal 43ddNn 43MO1 z }Ava $1773] sma NOILVWHO4 IVAYHNVA fal ras a Ee al oH S3NOZ 9 S3NOZ S 2 ( ) W40V3H = avai IWAYNVA TSONa 5 INVIHOVANY' Aanis sits | VTOVNW< 8 ¢ JO00VYEVD ' PENOBSCOT CO ASHLAND PERCE IS ANTICOSTI Text-figure 22.—Upper Ordovician stratigraphic sections (all to the scale shown for Penobscot County) and distribution of solitary rugose corals in Maine and southeastern Québec. 44 BULLETIN 314 with abundant intraformational limestone conglomer- ate, fine cross-bedding and channel fills, and gray shale partings and lenses. Inland outcrops include thinly- to thickly-bedded dense to fine-grained limestone with shale interbeds and partings, and nodular limestone. Toward the top of the upper member, colonial coral—stromatoporoid bioherms are overlain by irreg- ularly-bedded, dense to granular limestone with shale partings. The upper strata of the Vaureal are thinly- bedded, fine-grained to granular limestone with abun- dant intraformational limestone conglomerate, and thin interbeds or lenses of dense to semilithographic limestone with argillaceous partings. The uppermost beds are argillaceous nodular limestone. In his discussion of the English Head Formation, Twenhofel (1928, p. 31) noted that brachiopods are dominant and gastropods plentiful. He stated that ru- gose corals are rare compared to tabulates, and listed and described the diverse fauna. On the basis of the fauna and distribution of some species, Twenhofel (1928, pp. 63, 64) correlated the English Head with the ‘“Waynesville’’ of the Richmond Group in the Cincin- nati Arch region. Sinclair (1956, p. 1734) considered the English Head to be slightly older, equivalent to “some part of the Covington of Ohio and the Lorraine of New York and southern Quebec.”’ Bolton (1972, p. 8) noted that several genera in this interval are appar- ently confined to the Richmondian. Twenhofel (1928, p. 31) observed a greater abundance of corals higher in the section (his Vauréal Formation), and listed and described the large fauna. On the basis of this fauna and the vertical distribution of some species, Twen- hofel (1928, p. 65) correlated his Vauréal with the ‘‘Liberty’’ through ‘‘Elkhorn’’ of the Richmond Group. In the lower gray shale unit of the subsurface Vau- réal Formation, as it is presently defined, Jansonius (1967, p. 357) recorded early to middle Caradoc chi- tinozoans. The graptolites (Riva, 1969) and trilobites (Bolton, 1970) indicate a Lorraine-Ashgill-Harjuan age. Most of the lower member of the Vauréal was placed in the Dicellograptus complanatus zone by Riva (1969, p. 550, fig. 16). Chitinozoans in this zone were considered to be upper Caradoc—lower Ashgill by Achab (1977a). Riva (1969, pp. 550, 551, fig. 16) placed the upper member of the Vauréal in the Cli- macograptus prominens-elongatus (=Amplexograp- tus inuiti; see Riva and Petryk, 1981, p. 160) zone, which was considered to be post-Ashgill but pre-Llan- dovery in age. These strata contain late Caradoc chi- tinozoans according to Jansonius (1967, p. 357). Achab (1977b) noted that the chitinozoans are distinctive and have not been reported elsewhere. A sparse Upper Ordovician microfauna of ostracodes and a foraminifer was described from the exposed portion of the Vauréal Formation by Copeland (1970). Nowlan and Barnes (1981, p. 5) determined that conodonts of the exposed Vaureéal are predominantly characteristic of Fauna 12 (Sweet, Ethington, and Barnes, 1971), which is late Maysvillian—Richmondian, although some range down into Fauna 11. They also noted that the presence of Gamachignathus may indicate a latest Ordovician (Gamachian) age for the upper part of the Vauréal. The Vauréal Formation is conformably overlain by the Ellis Bay Formation, which is 50 to 95 m thick (Bolton, 1961, p. 6). It consists of gray shale with ar- gillaceous limestone, and units of interbedded lime- stone and shale. Six members were described by Bol- ton (1972, p. 8). Near the base of member 6, bioherms containing abundant colonial corals are up to 110 m long and 5 m high. The contact with the overlying Llandovery (Lower Silurian) Becscie Formation is dif- ficult to define because of the very gradual lithologic transition. Twenhofel (1928, p. 32) noted that the Ellis Bay fauna is more diverse and abundant than that in his Vaureal and English Head Formations, and con- tains almost 25 percent of the species in these earlier units as well as many new forms. He reported that brachiopods are the most abundant faunal element, and corals are more common than in his Vauréal and English Head. The fauna has a decided Richmondian aspect, but some species suggest a Silurian age (Twen- hofel, 1928, pp. 68, 69). Schuchert and Twenhofel (1910, pp. 700, 701) proposed the Gamachian Stage to include the Ellis Bay Formation and all American strata later in age than the youngest Richmondian of Ohio and Indiana but below clearly recognizable Si- lurian strata (Twenhofel, 1914, p. 8; 1928, pp. 35, 36). J. P. Ross (1960, pp. 1060, 1061) found that many bryozoans of the Vauréal and Ellis Bay Formations are closely related to those in the Richmond Group of Ohio and Maquoketa Group of Iowa, and did not sup- port the concept of a Gamachian Stage. Lespérance (1968b, pp. 151-153) noted a definite close correspon- dence among trilobites of the Richmond Group, the Ellis Bay Formation, and the early to middle Ashgill Remipyga (=Ceraurinus icarus; see Lespeérance, Sheehan, and Skidmore, 1981, p. 224) fauna within the White Head Formation at Percé, Québec. Riva (1969, p. 553) interpreted the Ellis Bay graptolites as being post-Ashgill but pre-Llandovery in age. Boucot (in Ayrton et al., 1969, p. 462) considered the formation to be of early Llandovery age on the basis of two brachiopod species. Bolton (1972, table 1) placed it in the Richmondian. Almost half of the Ellis Bay ostra- code species also occur in the Vauréal (Copeland, ORDOVICIAN RUGOSE CORALS: ELIAS 45 1973, p. 7), and this Ordovician assemblage has been traced to about 10 m below the top of the Ellis Bay Formation. Although many conodont taxa from the Vauréal Formation are present in the lower Ellis Bay, McCracken and Barnes (1981, p. 64) recognized Ga- machignathus as characteristic. Fauna 13 was pro- posed for this assemblage and considered Gamachian in age. The Ordovician-Silurian boundary was placed at the first appearance of Ozarkodina about 2 to 3 m above the base of member 6 within the Ellis Bay For- mation. Duffield and Legault (1981) suggested that a significant change in acritarch assemblages occurs at or near this horizon. Riva and Petryk (1981) studied the graptolites and concluded that the systemic bound- ary is located within a narrow interval represented by the bioherms of member 6 and the overlying | or 2 m of strata. Cocks and Copper (1981) assigned most of the Ellis Bay Formation to the Rawtheyan Stage of Europe on the basis of brachiopods. They reported an Hirnantia fauna near the top of the formation, indi- cating that the Hirnantian Stage of Europe is equiva- lent to the upper part of the Gamachian. Eight species of solitary corals are recognized from the Vauréal and Ellis Bay Formations (Text-fig. 22). Streptelasma affine (Billings, 1865) occurs in the lower and upper members of the Vauréal Formation and in the Ellis Bay Formation. Bighornia cf. B. patella (A. E. Wilson, 1926) is found in the lower member of the Vauréal. Grewingkia pulchella (Billings, 1865) and Helicelasma selectum (Billings, 1865) are present from the base of the upper member of the Vauréal Forma- tion, through the Ellis Bay Formation. Bodophyllum englishheadense n. sp. occurs at the base of the upper member of the Vauréal. Lobocorallium trilobatum vaurealense (Twenhofel, 1928) and Deiracorallium angulatum (Billings, 1862) are known from the upper part of the upper member of the Vauréal Formation. Paliphyllum ellisense (Twenhofel, 1928) is present in the Ellis Bay Formation. Lobocorallium trilobatum vaurealense and Helice- lasma selectum both occur in the upper member of the Vauréal Formation and in the early to middle Ash- gill Stenopareia faunal zone of the White Head For- mation at Percé, suggesting correlation of these units (Text-fig. 22). L. trilobatum vaurealense is also known from unit 4 (middle Ashgill) of the White Head. The range of H. selectum extends through the Ellis Bay Formation on Anticosti Island. The presence of L. trilobatum vaurealense and Deiracorallium angula- tum in the upper Vauréal Formation and the former in the early to middle Ashgill of the White Head For- mation suggests correlation of these strata with the Stony Mountain Formation in southern Manitoba. L. trilobatum trilobatum (Whiteaves, 1895) and a form of Deiracorallium very close to D. angulatum occur in the Gunn and Penitentiary Members of the Stony Mountain Formation. Twenhofel (1928, pp. 66, 67) considered the fauna in his zones 3 to 5 of the Vauréal Formation to indicate fairly positive correlation with the Stony Mountain. The lower member of the Vauréal and the Red River Formation of southern Manitoba (which underlies the Stony Mountain) may be Caradoc in age. Bighornia cf. B. patella occurs in both units, but is widespread geographically and stratigraphically (see ‘Systematic Paleontology’’). Three of the six solitary coral species in the upper member of the Vaureal Formation extend through the Ellis Bay Formation, indicating that the latter unit is Ordovician in age. Streptelasma affine, which is com- mon in the Ellis Bay, most closely resembles S. pri- mum (Wedekind, 1927) from the Ashgill Division Sa of Norway and Boda Limestone of Sweden. It is sim- ilar to S. subregulare (Savage, 1913) of the uppermost Ordovician (?Gamachian) in Missouri and Illinois, and S. unicum B. Neuman (1975), probably from the Hir- nantian Dalmanitina beds of Sweden. Paliphyllum el- lisense represents a genus found in member No. 3 of the Chasm Creek Formation, Churchill River Group, northern Manitoba, which correlates with the upper Stony Mountain Formation of southern Manitoba (Nelson, 1963, fig. 2). Paliphyllum is also known from the Upper Ordovician of Sweden, Estonia, and Sibe- ria, and the Llandovery (Lower Silurian) of Ohio and Estonia. The proposed location of the Ordovician-Si- lurian boundary within member 6 of the Ellis Bay For- mation (McCracken and Barnes, 1981; Duffield and Legault, 1981; Riva and Petryk, 1981) cannot be eval- uated on the basis of solitary Rugosa at this time be- cause the exact stratigraphic position of available specimens from that member is not known. Solitary Rugose Corals Streptelasma affine (Billings, 1865) occurs in the Vauréal Formation, and is common in the Ellis Bay Formation. Bolton (1981, p. 107) reported the species in bioherms within member 6 of the Ellis Bay. Spec- imens examined in this study show little evidence of pre-depositional abrasion, and apparently lived in low energy environments (PI. 5, figs. 4, 5, 9). They are ceratoid to trochoid and slightly to moderately curved in early ontogenetic stages, becoming cylindrical and usually straight in late stages (PI. 5, figs. 10, 14). Some corals have talons in early stages (Pl. 5, figs. 9, 10). Very large specimens have been collected in the upper Vauréal Formation (GSC 1987), and in Twenhofel’s (1928) zones 5 (YPM 28705) and 9 (YPM 28709) of the 46 BULLETIN 314 Ellis Bay Formation. Epizoans are fairly common on these corals (Pl. 5, fig. 9). In the Vaureal, they include stromatoporoids, bryozoans, and colonial corals. In Twenhofel’s zone 5 of the Ellis Bay, epizoic bryozo- ans, stromatoporoids, and cornulitids occur, and in his zones 7 and 9, bryozoans and stromatoporoids are present. Coarse rugae are regularly spaced on some corals in the lower Vauréal and in Twenhofel’s zones 5 and 9 of the Ellis Bay (Pl. 5, fig. 9). The size and growth form of this species and the abundance and diversity of associated epizoans suggest that environ- mental conditions were stable and very favorable for organisms during deposition of the Vauréal Formation and Twenhofel’s zones 5 and 9 of the Ellis Bay For- mation. Borings assigned to Trypanites weisei are present in only two of 29 specimens of S. affine. Mi- croscopic algal borings have been observed in eight of 16 corals for which thin sections were examined. Those seen in one specimen (YPM 28686) are consid- ered to be Holocene in age because they penetrate secondary calcite crystals. Helicelasma selectum (Billings, 1865) is uncommon in Twenhofel’s collection. Almost all specimens were abraded prior to final burial, indicating transportation in relatively high energy conditions (Pl. 6, fig. 12). They occur in argillaceous calcilutites and calcare- nites. Epizoans were not observed. Borings assigned to Trypanites weisei are present in one of ten corals. Microscopic algal borings were observed in four of five specimens for which thin sections were examined. Specimens of Deiracorallium angulatum (Billings, 1862) are well preserved and were not abraded prior to final burial, indicating that they lived in very low energy conditions (Pl. 6, figs. 21, 22, 25, 26). The species seems to be generally sparse, but is quite abundant in argillaceous limestones of the Potatoe River area (T. E. Bolton, 1977, pers. comm.). Epizo- ans and borings are not present on the 33 specimens examined. On the basis of available collections, Grewingkia pulchella (Billings, 1865) appears to be the most abun- dant Ordovician solitary coral on Anticosti Island. Specimens are generally not abraded, and presumably lived in low energy environments (PI. 12, figs. 7, 8, 11, 15). They occur in argillaceous limestones in associ- ation with bryozoans and brachiopods. One specimen (YPM 28757) was collected in a bioherm within the Ellis Bay Formation. The length-frequency histogram based on Twenhofel’s collection is unimodal, but it is not known if his sample accurately reflects the popu- lation (Text-fig. 23). Only one of more than 100 indi- viduals of G. pulchella has epizoic bryozoans. Borings assigned to Trypanites weisei are not present. Micro- scopic algal borings were observed in ten of 19 spec- imens for which thin sections were examined. Lobocorallium trilobatum vaurealense (Twenhofel, 1928) is rare in available collections. Bolton (1981, p. 107) reported the species in bioherms within the Vau- réal Formation. These large, trilobate corals were abraded in relatively high energy conditions prior to burial (PI. 13, fig. Is). One specimen (YPM 20482) oc- curs in argillaceous limestone with abundant brachio- pods, bryozoans, and arthropod fragments. At GSC locality 36157, this species is present in coarse-grained calcarenite. Epizoans and boring algae are not asso- ciated with the specimens that were examined, but one has abundant borings assigned to Trypanites weisei (Pl. 13, fig. Is). Bodophyllum englishheadense n. sp. is rare in Twenhofel’s collection. These corals have a base of attachment centered on the cardinal side, and in one specimen are epizoic on a bryozoan (Pl. 14, figs. 11, 14). All were abraded before burial, indicating rela- tively high energy conditions. Two specimens (YPM 28767, 28768) occur in calcilutite with brachiopods and arthropod fragments, and two others (YPM 28765, 28766) are in echinodermal calcarenite. Epizoans and borings are not present on the five corals examined. Bighornia cf. B. patella (A. E. Wilson, 1926) is rare in Twenhofel’s collection. All specimens have a spoon-shaped area of attachment on the concave car- dinal side near the tip (PI. 15, fig. 7). These corals were not abraded before burial, suggesting that they lived in low energy environments. Epizoans and borings are not present. Paliphyllum ellisense (Twenhofel, 1928) is uncom- mon in Twenhofel’s collection. Several of the speci- mens were collected from an Ellis Bay bioherm (YPM 28777, 28778). A few were slightly abraded before bur- ial. The corals are cylindrical and some have regularly 30 tet Ellis Bay Fm. n=114 + Vauréal Fm. n=11 O 15 30 length, mm Text-figure 23.—Length of specimens of Grewingkia pulchella (Billings, 1865) from the Vauréal and Ellis Bay Formations, Anti- costi Island, Québec. %f = percent frequency. n = number of spec- imens. ORDOVICIAN RUGOSE CORALS: ELIAS 47 STONINGTON SUBPROVINCE 2G deltensis ~ G. canadensis S. ivan ane a7 Ss. divaricans.©- oeteR RED RIVER- ‘ STONY MOUNTAIN : PROVINCE ee ~ MAQUOKETA SUBPROVINCE H. randi B. cf. B. patella H. randi EDGEWOOD PES iy PROVINCE S. subregulare S.leemonense S. sp. Bo. shorti ’ G.canadensis = _ i ivaricansioa S. divaricans G. canadensis ’ NORTH AMERICAN “ CONTINENTAL MARGIN — & BALTOSCANDIA RED RIVER- STONY MOUNTAIN PROVINCE S. affine H. selectum D. angulatum G. pulchella L. trilobatum vaurealense Bo. englishheadense B. cf. B. patella P. ellisense H. selectum G. sp. L. trilobatum vaurealense Bo.? sp. MARITIME SUBPROVINCE y G. rustica —— G. pulchella 0 [S Sassen Ss. fe G. See Lae aCe eS De fad Bo. neumani TAXA Fam. Streptelasmatidae B. Bighornia Bo. Bodophyllum . Deiracorallium . Grewingkia . Helicelasma . Kenophytlum . Lobocorallium Streptelasma . Paliphyllidae Paliphyllum Text-figure 24.—Paleobiogeography of latest Ordovician solitary rugose corals in eastern North America. spaced coarse rugae (PI. 15, fig. 20). This species prob- ably lived in a fairly low energy, stable environment. Epizoic bryozoans were observed on five of 26 spec- imens. Borings are not present. PALEOBIOGEOGRAPHY OF LATEST ORDOVICIAN SOLITARY RUGOSE CORALS IN EASTERN NORTH AMERICA OVERVIEW Latest Ordovician (Richmondian and Gamachian; Ashgill) solitary Rugosa of eastern North America are assigned to three provinces that are distinguished on the basis of assemblages and characteristic species (Table 3; Text-fig. 24). The distribution of these soli- tary coral provinces corresponds closely to paleo- geography and lithofacies (Text-fig. 2). The Richmond Province coincides with the Richmond Group. Solitary corals of the Maquoketa Group and those at the east- ern continental margin belong to the Red River—Stony Mountain Province. Those in the uppermost Ordovi- cian carbonate sequence of Oklahoma, Missouri, and Illinois are assigned to the Edgewood Province. The late Middle (?) through Late Ordovician Red River— 48 BULLETIN 314 Stony Mountain Province is by far the most extensive in space and time. The geographic and stratigraphic distribution of taxa within these provinces was deter- mined by regional environmental parameters related to paleogeography. RED RIVER—STONY MOUNTAIN PROVINCE Introduction The Red River—Stony Mountain Province extends from western Texas and New Mexico through west- central North America to Alaska, northern Greenland, and the Maritimes (Elias, 1981, pp. 2, 8, 10). The vast continental interior portion was occupied by shallow, interconnected epicontinental seas centralized in large areas of subsidence such as the Williston and Hudson Basins. Remarkably similar massive carbonate depos- its formed throughout the area, indicating widespread, stable, uniform environmental conditions (Flower, 1965, fig. 5). The epicontinental seas are thought to have been characterized by higher than normal tem- perature and salinity (Barnes and Fahraeus, 1975). Carbonate and clastic sediments were deposited in normal Ordovician open marine environments at the continental margin. The Red River—Stony Mountain Province is char- acterized by corals having unusual external form. Grewingkia includes species that are triangulate and trilobate in cross-section. Deiracorallium and Lobocorallium are compressed and trilobate, respec- tively. Bighornia is distinct in having the cardinal sep- tum on the concave side of the depressed coral. Di- versity in carbonate facies within the Red River—Stony Mountain Province is generally high. Maquoketa Subprovince The Maquoketa Subprovince (upper Mississippi val- ley) is characterized by the paucity and very low di- versity of solitary corals in carbonate beds within the Maquoketa Group, which is predominantly shale (Ta- ble 3; Text-fig. 24). Helicelasma randi Elias (1981) occurs in northeastern Iowa, northwestern Illinois, and southwestern Illinois. It is also present in the Sel- kirk Member of the Red River Formation (upper Mid- dle or Upper Ordovician) in southern Manitoba. With- in the Maquoketa Subprovince, Bighornia cf. B. patella (A. E. Wilson, 1926) is known only from the Fort Atkinson Formation in northeastern Iowa. This species also occurs in the Red River and Stony Moun- tain Formations of southern Manitoba, and at other localities in the Red River—Stony Mountain Province (see ‘‘Systematic Paleontology’’). The presence of identical species on both sides of the Transcontinental Arch indicates that migration across this slightly pos- Table 3.—Latest Ordovician solitary rugose corals in paleobio- geographic provinces and subprovinces, eastern North America. Red River—Stony Mountain Province Maquoketa Subprovince Helicelasma randi Elias (1981) Bighornia cf. B. patella (A. E. Wilson, 1926) Maritime Subprovince Streptelasma rankini n. sp. S. affine (Billings, 1865) Helicelasma selectum (Billings, 1865) Deiracorallium angulatum (Billings, 1862) Grewingkia penobscotensis n. sp. G. pulchella (Billings, 1865) Grewingkia sp. Lobocorallium trilobatum vaurealense (Twenhofel, 1928) Kenophyllum? sp. Bodophyllum neumani n. sp. Bodophyllum? sp. B. englishheadense n. sp. Bighornia cf. B. patella (A. E. Wilson, 1926) Paliphyllum ellisense (Twenhofel, 1928) Richmond Province Cincinnati Subprovince Streptelasma divaricans (Nicholson, 1875b) Grewingkia canadensis (Billings, 1862) Stonington Subprovince Streptelasma divaricans (Nicholson, 1875b) Grewingkia deltensis n. sp. Lake St. John Subprovince Grewingkia rustica (Billings, 1858a) Edgewood Province Streptelasma leemonense n. sp. Streptelasma sp. S. subregulare (Savage, 1913) Bodophyllum shorti n. sp. itive structure took place at least periodically during the late Middle (?) to Late Ordovician. H. randi and B. cf. B. patella became extinct in the Maquoketa Subprovince when the eastern North American epi- continental sea withdrew at the end of the Richmond- ian. Maritime Subprovince A diverse assemblage of solitary corals occurs on the continental margin at Anticosti Island and Perce, Québec, and northern Maine (Table 3; Text-fig. 24). Bighornia cf. B. patella (A. E. Wilson, 1926), a Red River—Stony Mountain species of wide geographic and considerable stratigraphic range, occurs with Strep- telasma affine (Billings, 1865) in the lower member of the Vauréal Formation on Anticosti Island. Deiracor- allium angulatum (Billings, 1862) of the upper member is very similar to a form in the Stony Mountain For- mation of southern Manitoba and the correlative ORDOVICIAN RUGOSE CORALS: ELIAS 49 Churchill River Group of northern Manitoba. Lobo- corallium trilobatum vaurealense (Twenhofel, 1928) is very close to L. trilobatum trilobatum (Whiteaves, 1895) of the Stony Mountain Formation. Also present in the upper member of the Vaureal Formation are S. affine, Helicelasma selectum (Billings, 1865), Grew- ingkia pulchella (Billings, 1865), and Bodophyllum en- glishheadense n. sp. In the vicinity of Percé, Quebec, L. trilobatum vaurealense is known from unit 4 of the White Head Formation, and occurs with H. selectum, Grewingkia sp., and Bodophyllum? sp. in the Steno- pareia faunal zone at Grande Coupe. S. affine, H. selectum, and G. pulchella of the Vaureal Formation extend into the Ellis Bay Formation on Anticosti Is- land. Also present in the Ellis Bay is Paliphyllum el- lisense (Twenhofel, 1928), representing a genus found within the Red River—Stony Mountain Province in northern Manitoba. G. pulchella, apparently the most abundant species on Anticosti Island, also occurs in the clastic facies near Ashland, Maine. In Penobscot County, Maine, S. rankini n. sp., G. penobscotensis n. sp., Bodophyllum neumani n. sp., and Kenophyl- lum? sp. are present in clastic rocks. Although the species are unique to this locality, the generic assem- blage resembles that at Perce and Anticosti Island. Presence of the characteristic genera Lobocoral- lium, Deiracorallium, and Bighornia indicates that the carbonate facies of the Anticosti-Percé region was de- posited within the Red River—Stony Mountain Prov- ince. Equivalence of taxa at the species level, espe- cially with southern Manitoba, suggests communication via the northern Canadian Shield during Late Ordo- vician time. Although taxa characteristic of the Red River—Stony Mountain Province are not known from Maine, the presence of G. pulchella at Anticosti Island and Ashland demonstrates that the carbonate and clas- tic facies were connected. In addition to the three gen- era listed above, Grewingkia, Helicelasma, and Pali- phyllum are also represented at the margins and interior of the Red River—Stony Mountain Province. However, Streptelasma and Bodophyllum are un- known from the continental interior. The presence of these two genera and several species that are relatively widespread at the eastern continental margin of North America (L. trilobatum vaurealense, H. selectum, and G. pulchella) serve to distinguish the Maritime Sub- province. Solitary corals of the Upper Ordovician Centrum Formation in northeastern Greenland were described by Scrutton (1975, pp. 15-17, pl. 2, figs. 1-5). Strep- telasma sp. cf. S. primum and Helicelasma sp. A are similar to S. affine and Grewingkia pulchella, respec- tively, of the Maritime Subprovince. Red River species of the continental interior occur in the Troeds- son Cliff and Cape Calhoun Formations of northwest- ern Greenland (Elias, 1981, p. 10). A latest Ordovician generic assemblage similar to that of the Maritime Subprovince occurs in the eastern Great Basin (south- western United States), where Budge (1977) reported Lobocorallium, Deiracorallium, Bighornia, Strepte- lasma, cf. Grewingkia, Bodophyllum, and ‘‘Tryplas- ma’’. Streptelasma, Grewingkia, Bodophyllum, Heli- celasma, Tryplasma, and Paliphyllum are also present in Baltoscandia (Table 4). It appears that solitary coral assemblages at the continental margin around North America are characterized by Red River—Stony Moun- tain species of the continental interior in association with genera (but not species) that also occur in Bal- toscandia. This generic similarity probably reflects similar normal Ordovician open marine environments. Baltoscandian brachiopods (Sheehan, 1975; Sheehan and Lespérance, 1979) and conodonts (Barnes and Fahraeus, 1975) are also present at the continental margin around North America. The north European affinity of the eastern conti- nental margin fauna has been emphasized repeatedly and used for biostratigraphic correlation. The brachio- pod and trilobite assemblages in the two regions have many species in common (see discussions under **Pe- nobscot County, Maine’’, ‘“‘Ashland, Maine’’, and ‘*Percé, Québec’’). It is noteworthy that solitary ru- gose corals not restricted to the Maritime Subprovince are conspecific with or close to forms in the continen- tal interior portion of the Red River—-Stony Mountain Province. Because of this, correlations with European sections, based on brachiopods and trilobites, can be extended into the continental interior of North Amer- ica using solitary corals. An early to middle Ashgill age is suggested for the Stony Mountain Formation in southern Manitoba, and the underlying Red River For- mation may be of Caradoc age (see discussion under “Anticosti Island, Québec’’). RICHMOND PROVINCE Introduction The Richmond Province occupies a narrow belt ex- tending northward from the Nashville Dome of Ten- nessee, along the Cincinnati Arch region of Kentucky, Indiana, and Ohio to northern Michigan, and eastward through southern Ontario and Québec (Table 3; Text- fig. 24). It coincided with a carbonate platform at the margin of an epicontinental sea that received clastic sediments from the Queenston delta (Ontario, New York, Pennsylvania, and Ohio). A great variety of en- vironments was present, ranging from open waters of BULLETIN 314 Table 4.—Solitary rugose coral genera in the Ashgill of Scandinavia (compiled from B. Neuman, 1968, 1969, 1975). Division 5b and the Dalmanitina beds contain the characteristic Hirnantia fauna. The Boda Limestone, which consists of reef core and flank deposits, probably corresponds in part to the Dalmanitina facies. It does not contain the typical Hirnantia fauna, but more characteristic elements occur in increasingly shaly beds to the south (P. J. Lespérance, 1978, pers. comm.). Norway Dalmanitina beds Boda Limestone the platform margin, where colonial coral banks de- veloped, to restricted hypersaline lagoons. As would be expected in an area of clastic sedimentation, soli- tary coral diversity was very low. The genera Grew- ingkia and Streptelasma are represented by G. can- adensis (Billings, 1862), G. rustica (Billings, 1858a), G. deltensis n. sp., and §. divaricans (Nicholson, 1875b). G. canadensis occurs in northern Tennessee, the Cincinnati Arch region, eastern Wisconsin, on Drummond Island, Michigan, Manitoulin Island, On- tario, and at Meaford, Ontario. S. divaricans is pres- ent in the Cincinnati Arch region, northern Michigan, and on Manitoulin Island. The relatively large central portion of the Richmond Province where G. canaden- sis and often S$. divaricans are found is termed the Cincinnati Subprovince. What this assemblage lacks in taxonomic diversity is offset by great intraspecific variability. The number of septa at a particular coral diameter and the axial region are highly variable. At Little Bay de Noc in northern Michigan, S. divaricans and G. deltensis are present. The latter species is unique to this area, which is termed the Stonington Subprovince. G. rustica occurs at Lake St. John, Qué- bec, and the single specimen found on Manitoulin Is- land was transported from an unknown source. The area of the Richmond Province occupied by G. rustica Hl yet) Fam. Streptelasmatidae | 0 ce) ® a oO is @ 3 x £ = o o 7) > Gil} Geel clan adh £ 2 o o = : a g = c _ © ‘< > = Ol || Gl Ohl Sill e << © ag a a = ve = a Grewingkia is termed the Lake St. John Subprovince. Its exact boundary with the Cincinnati Subprovince is uncertain because corals in the vicinity of Montréal, Québec, and Streetsville, Ontario, have not been identified at the species level. Origin Solitary corals of the Richmond Province first ap- peared in carbonate beds at the base of *‘Waynesville”’ strata in the Richmond Group. Those in the lower Arnheim Formation of Tennessee may also be of ‘“Waynesville’’ age. Solitary Rugosa are unknown in Upper Ordovician strata underlying the Richmond Group. They may have been introduced to this geo- graphic region during an early Richmondian transgres- sion. The source was probably to the west, where sol- itary corals are known from Edenian-Maysvillian strata of the Maquoketa Group. Those in the *‘Tren- tonian’’—-lower Cincinnatian of Minnesota, described as Streptelasma corniculum Hall (1847) and S. rusti- cum (Billings, 1858a) in Winchell and Schuchert (1895, pp. 90, 91, 93, pl. G, figs. 20-23), resemble Grewingkia canadensis and G. rustica externally, and the ‘‘Tren- tonian’’ §. (?) parasiticum Ulrich (in Winchell and Schuchert, 1895, pp. 89, 90, fig. 6) is remarkably sim- ilar in growth form to S. divaricans. A detailed study ORDOVICIAN RUGOSE CORALS: ELIAS 51 of solitary corals in the upper Middle-lower Upper Ordovician of eastern North America is required to determine if the Richmond Group contains recurrent Blackriveran—‘‘Trentonian’’ forms (see Foerste, 1924, pp. 43-45). Grewingkia canadensis and G. rustica are virtually identical externally. A single specimen of G. rustica was found on Manitoulin Island at the base of the Meaford beds, in which G. canadensis occurs. It had been transported from an unknown source, but sug- gests close relation in space and time between the two species. It is possible that both were derived from a common ancestor, or G. rustica may have arisen from G. canadensis in the eastern digitation of the Rich- mond Province by geographic speciation very soon after introduction from the west. Grewingkia deltensis, which occurs within micritic limestone of the Ogontz Member of the Stonington Formation in northern Michigan, has the trochoid, moderately curved form and large size typical of species of Grewingkia within massive carbonates of the Selkirk Member of the Red River Formation (up- per Middle or Upper Ordovician) in southern Mani- toba (Elias, 1981). It is present in the digitation of the Richmond Province nearest Manitoba. Selkirk Mem- ber species of Bighornia and Helicelasma occur in the Maquoketa Group to the southwest, indicating that dispersal across the Transcontinental Arch was pos- sible. G. deltensis may have arisen from Red River forms, but it was unable to migrate farther into the Richmond Province because suitable environments re- sulting in Ogontz-type deposition were not present elsewhere. Subsequent History Following introduction into the belt of Richmond Group sedimentation, solitary corals dispersed later- ally as favorable environments became more wide- spread. They attained their maximum geographic range during ‘‘Liberty—early Whitewater’? time. Mi- gration out of and into the Richmond Province was restricted shoreward by the Queenston delta and Ta- conic upland, the positive Nashville Dome, and the Canadian Shield, which was probably slightly positive (Copper and Grawbarger, 1978, p. 1990; see discussion under ‘‘Meaford, Ontario’’). Seaward of the carbonate platform, deeper water in which the Maquoketa Group shale was deposited proved to be an impenetrable bar- rier. Progradation of the Queenston delta eliminated corals from the Montréal, Streetsville, and Meaford areas of southern Québec and Ontario during Rich- mondian time. Extinction of Richmond Province species resulted from withdrawal of the eastern North American epicontinental sea at the end of the Rich- mondian, possibly due to a glacioeustatic sea-level drop. Presence of the Richmond Group fauna in car- bonate beds at the top of the Maquoketa shale at Little Sturgeon Bay, Wisconsin, may reflect this final west- ward retreat. To account for the different assemblages in regions corresponding to the Red River—Stony Mountain and Richmond Provinces, Flower (1946, p. 127) and Nel- son (1959a) suggested that the ‘‘Arctic Ordovician” (Red River—Stony Mountain) fauna of central North America was tropical in character, whereas the east- ern (Richmond) fauna was temperate. This widely cit- ed climatic influence need not be invoked, especially when it is seen that the Red River—Stony Mountain Province occurs on opposite sides and ends of the Richmond Province (Text-fig. 24). Paleogeography and the related type of sedimentation were the primary factors that determined the nature and extent of these faunas. Because species and assemblages of solitary corals (and many other faunal elements) in the two provinces are different, they cannot be used at present to correlate the North American Upper Ordovician type sections in the Cincinnati Arch region with strata outside the Richmond Province. EDGEWOOD PROVINCE The Edgewood Province coincides with the carbon- ate sequence deposited during a latest Ordovician (?Gamachian) transgression into the continental inte- rior (Illinois, Missouri, and Oklahoma) (Table 3; Text- fig. 24). Normal Ordovician open marine environments are indicated by the development of oolite shoals and small bioherms. As would be expected in such envi- ronments, the solitary corals (and brachiopods) resem- ble those that previously occurred only at the conti- nental margin, and are different from those of the continental interior Red River—Stony Mountain and Richmond Provinces. Streptelasma subregulare (Sav- age, 1913) of northeastern Illinois and northeastern and southeastern Missouri is the most widely distrib- uted solitary coral in this province. It is similar to S. affine (Billings, 1865) of Anticosti Island, and most closely resembles S. unicum B. Neuman (1975) of Sweden. S. leemonense n. sp., Streptelasma sp., and Bodophyllum shorti n. sp. are present in southeastern Missouri. B. shorti is the only representative of the genus known from the continental interior of North America. S$. subregulare and Streptelasma sp. have been reported from the Arbuckle Mountains (Max- well, 1936), but these identifications require confir- 52 BULLETIN 314 mation. Extension of the Edgewood Province into Oklahoma is therefore tentative. The latest Ordovician transgression that marked the beginning of Middle Paleozoic carbonate deposition in the east-central interior of North America probably proceeded from the south, and may have been related to deglaciation. The associated introduction of solitary coral and brachiopod assemblages that resemble those previously occurring only at continental margins fore- shadowed the cosmopolitan Silurian faunas (Kaljo and Klaamann, 1973; Sheehan, 1975; Sheehan and Les- perance, 1979, p. 952). Laub (1975; 1979, pp. 45, 52) found that corals of the middle Llandovery (Lower Silurian) Brassfield Formation in the Cincinnati Arch region were geographically restricted, but show great- est similarity to those of the eastern North American continental margin. Although assemblages in the Edgewood Province, Baltoscandia, and continental margin portions of the Red River—Stony Mountain Province are similar, they have no species in common. The solitary corals in these assemblages reflect similar normal Ordovician open marine environments, and do not necessarily in- dicate close genetic relationship, geographic proximi- ty, or contemporaneity. SYSTEMATIC PALEONTOLOGY INTRODUCTION Morphologic terminology and biometric methods used herein were discussed by Elias (1981, pp. 3-5). Many morphologic features are described qualitatively (for example, ‘‘slightly curved’’, ‘“‘moderately con- vex’, “‘closely spaced’’). These terms relate speci- mens within the scope of this study, and their meaning is made clear by examination of the plates. The species recognized herein are considered valid because they are separated from all others by mor- phologic “‘gaps’’. Morphologic intergradation and the uncertain phylogenetic validity of Ordovician solitary streptelasmatid genera, as presently defined, are dis- cussed for each genus. Unfortunately, knowledge of these corals is insufficient to satisfactorily resolve all difficulties at this time. Assignment of species to these genera serves to indicate particular gross morphologic features, although it is uncertain if they were deter- mined by environment, genotype, or both. Differences in taxonomic composition among assemblages are a reflection of these factors, and the paleobiogeographic conclusions of this study are therefore thought to be valid. Order RUGOSA Milne-Edwards and Haime, 1850 Family STREPTELASMATIDAE Nicholson in Nicholson and Lydekker, 1889 Genus STREPTELASMA Hall, 1847 1847. Streptelasma Hall, p. 17 (as Streptoplasma) and page facing p. 338 (see Laub, 1979, p. 60). 1969. Streptelasma Hall. B. Neuman, pp. 8-10. 1974. Streptelasma Hall. McLean, pp. 38-41. 1979. Streptelasma Hall. Laub, pp. 59-61. Type Species (by subsequent designation).—Strep- telasma corniculum Hall (1847, p. 69); selected by Roemer (1861, p. 19). Lower Trenton Limestone (up- per Middle Ordovician); Middleville, New York, U.S.A. Discussion.—The present concept of Streptelasma is based on B. Neuman’s (1969, pp. 8-11) study of the type species. The genus includes streptelasmatids with non-dilated to moderately dilated major septa that gen- erally are fused into a simple axial structure in early to intermediate ontogenetic stages. In later stages, the major septa are non-dilated and comparatively short, usually not forming an axial structure (see B. Neuman, 1969, fig. 3). McLean (1974, p. 39) discussed the uncertain rela- tionships of Streptelasma, Porfirieviella Ivanovskiy (1963), and Dinophyllum Lindstrom (1882), and stated that ‘‘future study of a larger variety of material may reveal that differences between these two genera and Streptelasma are merely gradational, in which case they should all be considered synonymous.’ B. Neu- man (1977, p. 71) considered the tabellae of Porfiriev- iella and Dinophyllum unrelated to the complete tab- ulae typical of Streptelasma. The following points must be noted in establishing the relationships of Streptelasma, Borelasma B. Neuman (1969), Helice- lasma B. Neuman (1969), and Grewingkia Dybowski (1873): 1. Streptelasma includes corals having non-dilated and moder- ately dilated major septa in early stages. However, otherwise similar forms with greatly dilated septa are assigned to Bore- lasma and Helicelasma (see B. Neuman, 1969, figs. 22, 56). This boundary between Streptelasma and the latter two genera seems arbitrary. . The single species S. divaricans (Nicholson, 1875b) is highly variable and includes corals having an open axial region (as in Streptelasma), those in which major septa extend to the axis (also considered to be Streptelasma), and forms with an axial structure comparable in complexity to Grewingkia. tN Further study may demonstrate that these genera are synonymous. A knowledge of variation within the type species §. corniculum is vital to this problem, but at present only the lectotype is known (B. Neuman, 1969, pp. 10, 11). ORDOVICIAN RUGOSE CORALS: ELIAS Streptelasma divaricans (Nicholson, 1875b) Plate 1, figures 1-41; Plate 2, figures I-16; Plate 3, figures 1-23 1875b. Palaeophyllum divaricans Nicholson, pp. 220, 221, pl. 22, fig. 10, 10a, 10b. 1882. Palaeophyllum divaricans Nicholson. Hall, pp. 377, 378, pl. 52, fig. 4. 1908. Streptelasma divaricans (Nicholson). Cumings, pp. 707, 708, pl. 1, tig. 6, 6a. 1909. Streptelasma divaricans (Nicholson). Foerste, pp. 307, 308, pl. 10, fig. 4a—-e. 1909. Streptelasma divaricans-angustatum Foerste, p. 308, pl. 9, fig. 6a, 6b. 1918. Streptelasma cf. divaricans (Nicholson). Foerste, p. 99, pl. 4, fig. 2. 1924. Streptelasma divaricans (Nicholson). Foerste, p. 67, pl. 2, fig. Sa—d. Lectotype (designated herein) —FMNH UC413; “Cincinnati Group, Cincinnati, Ohio’’; U. P. James collection (Nicholson, 1875b, pl. 22, fig. 10; Pl. 3, figs. Is, 2s). Other Specimens.— UCGM 45000-45143, 45611, 45646; Richmond Group; Cincinnati Arch region of Ohio, Indiana, and Kentucky (see Text-fig. 3 for stratigraphic positions and locations); Elias collection. UCGM 45144, 45145; ‘‘Whitewater’’ strata of the Richmond Group; entrance to Hueston Woods Park, Oxford, Ohio; Elias collection. USNM 311625; *‘Waynesville’’ strata (base of Clarksville beds) of the Richmond Group; near Clarks- ville, Ohio. USNM 311628, 311629; *‘Waynesville’’ strata (Blanchester beds) of the Richmond Group; near Clarksville, Ohio. USNM 135761; **Waynesville’’ strata (Blanchester beds) of the Richmond Group; southwest of Blan- chester, Ohio. USNM 40086; ‘‘Whitewater’’ strata of the Rich- mond Group; Oxford, Ohio. USNM 42517; middle Richmond Group; Oxford, Ohio. USNM 311660-311662; ‘‘Whitewater’’ strata of the Richmond Group; USGS locality 4343-CO, B&O rail- road cut (Cincinnati, Indianapolis, and Western Rail- road, NE, sec. 21, TSN, RIE, College Corner Quad- rangle), just northwest of Oxford, Ohio; Boardman collection. USNM 135767; ‘‘Whitewater’’ strata of the Rich- mond Group; Richmond, Indiana. USNM 84868 (2 syntypes of S. divaricans-angus- tatum); *‘Whitewater”’ strata of the Richmond Group; Osgood, Indiana. USNM 84869A-D (4 specimens); *‘Whitewater”’ in Ww strata of the Richmond Group, 3.0 to 4.5 m below Brassfield Formation; Osgood, Indiana. USNM 50816; Richmond Group; Bardstown, Ken- tucky. USNM 78449 [S. cf. divaricans of Foerste (1918)]; Bay de Noc Member of the Stonington Formation; Stonington, Delta County, Michigan; Stratton collec- tion. UCGM 45146-45152; Kagawong beds, upper mem- ber of the Georgian Bay Formation; locality 19f, Man- itoulin Island, Ontario (see Text-fig. 18 for stratigraph- ic position and location); Elias collection. GSC 66635, 66636; Meaford beds, upper member of the Georgian Bay Formation; locality M6la, Manitou- lin Island, Ontario (see Text-fig. 18 for stratigraphic position and location). Occurrence.—Upper Ordovician (Richmondian): ‘“Waynesville”’ strata to top of Richmond Group; Cin- cinnati Arch region of Ohio, Indiana, and Kentucky, U.S.A. Meaford and Kagawong beds, upper member of the Georgian Bay Formation; Manitoulin Island, Ontario, Canada. Bay de Noc Member of the Ston- ington Formation; Delta County, Michigan, U.S.A. Diagnosis.—Coral with base of attachment, gener- ally solitary but also occurring as pseudocolonies and rarely colonies resulting from lateral and peripheral increase. Axial region highly variable in late stage, from moderately complex axial structure of septal lobes and lamellae, to septal lobes only, to septa ex- tending to axis, to septa withdrawn from axis—mayjor septa most commonly extend to axis without forming axial structure. Description of Corals.—The length-frequency dis- tribution of corals is shown in Text-figure 14 (see dis- cussion under **Cincinnati Arch Region’’). The longest specimen examined (UCGM 45013) has a length of 32 mm and diameter of 15 mm immediately below the calice where 32 major septa are present. The corals are generally ceratoid, but some are tro- choid. They rarely become cylindrical in late stages (UCGM 45025, USNM 84868). Most are slightly curved, but they vary from straight to moderately curved. The cardinal-counter surface is often slightly curved or twisted. The corals have a relatively small to large base of attachment generally centered on the cardinal side, and less commonly toward an alar side. Some speci- mens have basal extensions or talons (PI. 3, fig. 11s). This species is usually attached to bryozoans (see dis- cussion under “Cincinnati Arch Region’’). In some specimens the outer wall is absent at the site of at- tachment, and the septa are connected directly to the bryozoan (PI. 3, fig. 7). Septal grooves and interseptal ridges are present on the epitheca. 54 BULLETIN 314 Coralla generally occur individually, but 26 percent of 189 specimens consist of two or more in lateral contact (Text-fig. 13). The most seen in a single group is 13 (USNM 84869D, Foerste, 1909, pl. 10, fig. 4e). Most of these clusters apparently represent pseudo- colonies. Often the tips are separate and the coralla expand upward into lateral contact. Less commonly, 4O iO) Ze O 4 the tips are in contact or the tip of one coral is attached to the side of another, but separating walls are present. In only two specimens has lateral and peripheral in- crease resulting in true coloniality been demonstrated (see “‘Blastogeny’’ below). In one specimen, the walls separating two coralla opened in late stages (USNM 311660, Pl. 2, figs. 14, 15s). Two specimens show at- 172 sections from 96 corals 8 12 16 diameter, mm Text-figure 25.—Relation between number of major septa (n) and coral diameter in Streptelasma divaricans (Nicholson, 1875b) from the entire Richmond Group, Cincinnati Arch region. Numbers indicate frequency of a point if greater than one. Curve determined by inspection using class averages. X = USNM 84868a [syntype of 8. divaricans-angustatum Foerste (1909)], *‘Whitewater”’ strata, Richmond Group, Osgood, Indiana. O = USNM 78449a [S. cf. divaricans of Foerste (1918)], Bay de Noc Member, Stonington Formation, Stonington, Michigan. ORDOVICIAN RUGOSE CORALS: ELIAS 55 tempted rejuvenation in later stages (UCGM 45070; USNM 311661, Pl. 2, fig. 16s). Depth of the calice is 35 to 55 percent of the coral length. The calicular boss, when developed, is slightly convex (PI. 2, fig. 8). Ontogeny and Internal Structures.—In early stages the major septa commonly extend to or almost to the axis. In later stages a moderately complex axial struc- ture of septal lobes and lamellae may develop, or a few septal lobes only may appear, or the major septa may extend to the axis, or the major septa may be- come withdrawn from the axis. There is a complete range of variation from corals with complex axial structures to those with open axial regions (PI. 1, figs. 1-19; Text-fig. 16). Specimens with major septa ex- tending to the axis are most common. The number of major septa at a particular diameter is shown in Text-figure 25. The septa are commonly non-dilated. In a few corals the septa are slightly to moderately dilated, especially in early stages (UCGM 45018; UCGM 45128, Pl. 2, figs. 1-4). The major septa are generally wavy and twist in a counterclockwise direction in some specimens (PI. 1, fig. 17). They com- monly meet in several groups at the axis. The cardinal septum is indistinct, and a fossula is not developed. Minor septa are confined to or extend a short distance beyond the stereozone, which is generally narrow. Tabulae first appear in very early stages (PI. 2, fig. 8). They are mostly complete and moderately convex upward. Complementary plates (see B. Neuman, 1969, p. 6) are present in the septal region. Blastogeny.—In one specimen (UCGM 45646), an offset resulted from lateral increase and another arose by peripheral increase as follows (refer to Text-fig. 26): Lateral increase. The offset (a) developed in a lateral protuberance of the elongate protocorallite. The parent septa were initially withdrawn from this region. It is not known if septa in the offset repre- sent peripheral ends of parent septa that were left behind. A wall separating the protocorallite and off- set appears as a dense region in Text-figure 26E, Text-figure 26.—Blastogeny in Streptelasma divaricans (Nicholson, 1875b) [UCGM 45646, x5] (see Pl. 2, fig. 11). a = offset resulting from lateral increase. b = offset resulting from peripheral increase. 56 BULLETIN 314 and is better defined in F. This offset was short lived, and is absent after J. Peripheral increase. The offset (b) developed in a thickened portion of the protocorallite wall (Text- fig. 26C, D). The offset initially expanded inward at the expense of the protocorallite (E—J), as is typical of peripheral increase. Later, however, the offset curved away from the protocorallite (Pl. 2, fig. 11). The septal arrangement is irregular until L. Increase in a second specimen (UCGM 45093) is in- dicated by an incomplete wall that partially separates two corallites in early stages and becomes complete in later stages (Pl. 2, figs. 12, 13). Lateral increase probably occurred in a third specimen (UCGM 45036). Microstructure.—Septal fibers are well developed only in dilated stages (Pl. 2, fig. 9). Trabeculae are inclined slightly up toward the axis (Pl. 2, fig. 8). La- mellae in the stereozone are well developed only in non-dilated stages when the septa are relatively far apart (Pl. 2, fig. 10). The outer wall of the coral is composed of fibers oriented perpendicular to the in- terseptal ridges (Pl. 2, figs. 9, 10). Discussion.—One of the two specimens figured ex- ternally by Nicholson (1875b, pl. 22, fig. 10) in the original description of Palaeophyllum divaricans is herein designated as the lectotype (FMNH UC413, PI. 3, figs. Is, 2s). His other specimen (pl. 22, fig. 10a) has not been located. The source of Nicholson’s trans- verse section (pl. 22, fig. 10b) is unknown. Streptelasma divaricans (Nicholson, 1875b), origi- nally described from the Cincinnati Arch region, was assigned to Palaeophyllum by Nicholson (1875b) and Hall (1882), and to Streptelasma by later workers. Foerste (1909) distinguished S. divaricans-angustatum on the basis of its cylindrical form. However, its ex- ternal and internal characters have been found to lie within the range of variability of S. divaricans (PI. 2, fig. 5). On the basis of external morphology, a coral from Delta County, Michigan, was identified as S. cf. divaricans by Foerste (1918). This specimen has been sectioned and is S. divaricans (PI. 3, figs. 14s, 15). The species also occurs in the upper member of the Geor- gian Bay Formation on Manitoulin Island. The range of axial region variation within S. divar- icans spans the genera Streptelasma and Grewingkia as they are presently defined. The species is assigned to Streptelasma because an axial structure is not de- veloped in the majority of specimens. S. divaricans is distinct because it often forms pseudocolonies, and rarely forms colonies by lateral and peripheral in- crease. S. (?) parasiticum Ulrich (in Winchell and Schuchert, 1895, pp. 89, 90, fig. 6) from the **Tren- tonian”’ (upper Middle Ordovician) of Minnesota also forms pseudocolonies or colonies attached to bryozoa, but the coralla are only several mm long—internal structures are unknown. S. ostrogothicum B. Neuman (1969, pp. 21-23, fig. 13b, c) from the Upper Ordovi- cian of Sweden commonly produces several intraca- licular offsets by peripheral increase, but has long minor septa and a broad stereozone. Corals of S. di- varicans in which major septa extend to the axis re- semble S$. leemonense n. sp. from the ?Gamachian (Upper Ordovician) of Missouri. However, S. lee- monense is distinct in having very long minor septa. Streptelasma leemonense n. sp. Plate 4, figures 1-3 Derivation of Name.—The specific name refers to the town of Leemon, Cape Girardeau County, Mis- souri, near which the species occurs. Holotype.—UCGM 45614; Elias collection (Pl. 4, figs. 1, 2). Paratype. fig. 3). Occurrence.—Upper Ordovician (?Gamachian): Leemon Formation; locality 20a, Cape Girardeau County, Missouri, U.S.A. Diagnosis.—Solitary Streptelasma with major septa extending to or almost to axis during ontogeny. Minor septa very long, and may extend more than half the coral radius. Description of Corals.—The holotype is small and has 32 major septa at a diameter of 9 mm. The para- type has 24 major septa at a diameter of 7 mm. The corals are ceratoid and slightly curved. Ontogeny and Internal Structures.—The major sep- ta extend to or almost to the axis, where they meet in several groups. They are non-dilated throughout on- togeny. The cardinal septum is indistinct, and a car- dinal fossula is not present. The minor septa are very long, extending more than half the radius of the coral in the paratype. The stereozone is moderately broad. Tabulae are present. Microstructure.—The microstructure of these par- tially silicified specimens is unknown. Discussion.—Streptelasma leemonense n. sp. re- sembles those specimens of the Richmond Group species §. divaricans (Nicholson, 1875b) in which ma- jor septa extend to the axis. However, S. /eemonense is distinct in having very long minor septa. UCGM 45615; Elias collection (Pl. 4, Streptelasma sp. Plate 4, figures 4-6 Specimen.—UCGM 45616; Elias collection. Occurrence.—Upper Ordovician (?Gamachian): Leemon Formation; locality 20a, Cape Girardeau County, Missouri, U.S.A. ORDOVICIAN RUGOSE CORALS: ELIAS Si Description.—In this small solitary coral the major septa extend to or almost to the axis, where they meet in several groups throughout ontogeny. They are mod- erately dilated in early stages and non-dilated in later stages. The minor septa appear to be confined to the stereozone. Tabulae are present. Microstructure.—The major septa appear to be fi- brous, and lamellae are developed in the stereozone. Discussion.—This coral resembles Streptelasma leemonense n. sp., from the same locality, and typical Richmond Group specimens of S. divaricans (Nichol- son, 1875b) in that the major septa extend to or almost to the axis, where they meet in several groups. How- ever, the degree of septal dilation is greater in this coral. The minor septa are much shorter than in S. leemonense. The single specimen is poorly preserved because of secondary dissolution of the periphery, and a specific name is therefore not given. Streptelasma subregulare (Savage, 1913) Plate 4, figures 7-22 1913. Zaphrentis subregularis Savage, p. 62, pl. 3, fig. 5, pl. 7, fig. 1. 1913. Zaphrentis ambigua Savage, pp. 109, 110, pl. 7, fig. 2. 1917a. Zaphrentis subregularis Savage. Savage, p. 113, pl. 5, fig. 5, pl. 9, fig. 1. 1917a. Zaphrentis ambigua Savage. Savage, p. 149, pl. 9, fig. 2. Holotype (by original designation).—UI X-851; Cy- rene Formation, Edgewood Group; near Edgewood, Missouri; Savage collection (Savage, 1913, pl. 3, fig. 5; Savage, 1917a, pl. 5, fig. 5; Pl. 4, figs. 7s, 8). Other Specimens.— UI X-926 (2 specimens); Wilhelmi Formation (Chan- nahon Limestone of Savage); Will County, Illinois; Savage collection. UI X-947 (type specimens of Z. ambigua; one slab with 5 specimens plus a single specimen); Wilhelmi Formation (Channahon Limestone of Savage); near Channahon, Illinois; Savage collection. UCGM 45618-45634; Leemon Formation; locality 20b, Cape Girardeau County, Missouri; Elias collec- tion. Occurrence.—Upper Ordovician (?Gamachian): Wilhelmi Formation; Will County, Illinois, U.S.A. Cyrene Formation, Edgewood Group; Pike County, Missouri, U.S.A. Leemon Formation; Cape Girardeau County, Missouri, U.S.A. Diagnosis.—Solitary Streptelasma with major septa moderately dilated in early stage, non-dilated and withdrawn from axis to about half the coral radius in later stages. Cardinal septum becomes short, cardinal fossula prominent and broad in later stages. Description of Corals.—The largest specimen ex- amined (UCGM 45629) is 65 mm long, with a diameter of 29 mm in the calice where 37 major septa are pres- ent. The corals are trochoid (UCGM 45618, UI X-851) to usually ceratoid (UCGM 45619, UI X-947), and straight to slightly curved. Prominent septal grooves and interseptal ridges are present on the epitheca. Growth lines are preserved, and rugae are developed on some specimens. Depth of the calice is 40 (UCGM 45618) to 50 percent of the coral length (UCGM 45622). A calicular boss is not present. Ontogeny and Internal Structures.—In early stages the major septa extend to or almost to the axis, where they meet in several groups. In later stages they ex- tend about half way to the axis. The septa are wavy. The number of major septa at a particular diameter is shown in Text-figure 27. The major septa are mod- erately dilated in early stages and non-dilated in later stages. The cardinal septum becomes short in later stages, when a broad and prominent cardinal fossula is present. The minor septa are generally very short, and the stereozone is very narrow. The tabulae are complete, thin, very widely spaced, and somewhat ir- regular. They are convex upward in the septal region and horizontal to concave upward in the axial region. The tabulae are greatly depressed in the cardinal fos- sula (UI X-851, Pl. 4, fig. 7s). Microstructure.—The major septa are clearly fi- brous. Trabeculae are inclined up toward the axis. Lamellae appear to be present in the stereozone in non-dilated stages. Discussion.—Savage (1913, 1917a) distinguished Zaphrentis subregularis and Z. ambigua primarily on the basis of external form, but recognized that they were similar internally. Trochoid and ceratoid speci- mens were assigned to Z. subregularis and Z. ambi- gua, respectively. In the Leemon Formation, a com- plete gradation from trochoid to ceratoid forms with similar internal structure is present. Therefore, Z. am- bigua is a synonym of Z. subregularis, here assigned to Streptelasma. Streptelasma subregulare (Savage, 1913) resembles the lectotype of S. corniculum Hall (1847) from the Trenton (upper Middle Ordovician) of New York (B. Neuman, 1969, pp. 10, 11, figs. 4-6) in having mod- erately dilated septa in early stages, major septa that are withdrawn from the axis, short minor septa, and tabulae that are concave upward in the axial region. However, S. corniculum does not appear to have a short cardinal septum in a prominent fossula. Many specimens of S. affine (Billings, 1865) from the ?Ca- radoc through Ashgill (Upper Ordovician) of Anticosti Island, Québec, are similar to S$. swbregulare exter- nally and internally. The latter species is distinct in tn oo 4O BULLETIN 314 15 sections from 8 corals OS Te) 20 diameter, mm 30 Text-figure 27.—Relation between number of major septa (n) and coral diameter in Streptelasma subregulare (Savage, 1913). Numbers indicate frequency of a point if greater than one. having a short cardinal septum in a prominent fossula, and very short minor septa. S. subregulare most closely resembles S. unicum B. Neuman (1975) from the Hirnantian (Upper Ordovi- cian) or lowermost Llandovery (Lower Silurian) of Sweden. However, S. suwbregulare has a greater de- gree of septal dilation in early stages, more widely spaced tabulae, and slightly fewer septa at a particular diameter (see B. Neuman, 1975, fig. 17). Streptelasma rankini n. sp. Plate 5, figures 1-3 Derivation of Name.—The species is named for D. W. Rankin, whose field work for a doctoral disserta- tion at Harvard University resulted in recognition of Upper Ordovician rocks in Penobscot County, Maine. Holotype. —USNM 311736; R. B. Neuman collec- tion (PI. 5, figs. 1-3). Paratypes.—USNM 311737-311747; R. B. Neuman collection. Occurrence.—Upper Ordovician (Ashgill): About 520 m above base of unnamed formation; between Pond Pitch and Haskell Rock Pitch, East Branch, Pe- nobscot River, Penobscot County, Maine, U.S.A. Solitary Streptelasma with major septa Diagnosis. generally slightly withdrawn from axis during ontog- eny. Tabulae steeply convex upward at margins but almost horizontal or slightly concave upward axially. Description of Corals. —The specimens are poorly preserved and incomplete. The largest coral examined (USNM 311737) has a diameter of 22 mm and 42 major septa at an unknown distance below the calice. The specimens are ceratoid. All but one (USNM 311747) appear to be straight. One individual (USNM 311738) may have a base of attachment. Internal Structures.—The number of major septa at 40 13 sections from 12 corals diameter, mm Text-figure 28.—Relation between number of major septa (n) and coral diameter in Streptelasma rankini n. sp. Numbers indicate fre- quency of a point if greater than one. ORDOVICIAN RUGOSE CORALS: ELIAS 59 a particular diameter is shown in Text-figure 28. The major septa are generally slightly withdrawn from the axis in all observed ontogenetic stages. They are non- dilated and wavy. The cardinal septum is indistinct, and a fossula is not developed. Minor septa commonly extend a moderate distance beyond the stereozone, but may be very long (USNM 311739). The stereozone is moderately broad. The tabulae are thin and mostly complete. They are steeply convex upward at the mar- gins, but become almost horizontal or are slightly con- cave upward axially. Complementary plates (see B. Neuman, 1969, p. 6) are present in some specimens. Microstructure.—The corals are poorly preserved. Septal fibers cannot be distinguished, but weakly de- veloped trabeculae that are slightly inclined up toward the axis may be present. Discussion.—Streptelasma rankini n. sp. resembles some specimens of S. affine (Billings, 1865) from the ?Caradoc through Ashgill (Upper Ordovician) of An- ticosti Island, Québec, and S$. primum (Wedekind, 1927) from the Ashgill of Norway in growth form and in having major septa withdrawn from the axis. How- ever, S. rankini has tabulae that are much more steep- ly convex upward at the margins. Streptelasma affine (Billings, 1865) Plate 5, figures 4-18 1865. Zaphrentis affinis Billings, p. 430. 1865. Zaphrentis bellistriata Billings, pp. 430, 431. 1866. Zaphrentis affinis Billings. Billings, p. 7. 1866. Zaphrentis bellistriata Billings. Billings, p. 8. 1901. Zaphrentis affinis Billings. Lambe, pp. 118, 119, pl. 7, fig. 6, 6a, 6b. 1928. Zaphrentis affinis Billings. Twenhofel, pp. 114, 115. 1981. Streptelasma affinis (Billings). Bolton, pl. 3, figs. 3-8. Lectotype (designated herein).—GSC 1987, 1987c-e: upper member, about 30+ m below top of Vauréal Formation; Wreck Point, Anticosti Island, Québec; T. C. Weston collection, 1865. Paralectotypes (designated herein).—GSC 1987a, b (Lambe, 1901, pl. 7, fig. 6, 6a); GSC 1987g, 1; GSC 1987f, h; upper member, about 30+ m below top of Vaureal Formation; Wreck Point, Anticosti Island, Québec; T. C. Weston collection, 1865. Other Specimens.— (All from Anticosti Island, Québec; Twenhofel col- lection unless otherwise stated.) GSC 2244, 2244a, b (syntype of Zaphrentis belli- striata); upper member, about 30+ m below top of Vauréal Formation; Wreck Point; T. C. Weston col- lection, 1865. YPM 28687; lower member of the Vauréal Forma- tion (Twenhofel’s zone 4, English Head Formation); Carleton Point. YPM 28688; Ellis Bay Formation; cliff 1.2 km east of Junction Cliff. YPM 28689, 28693; Ellis Bay Formation; Prinsta Bay. YPM 28690; Ellis Bay Formation; near Junction Cliff. YPM 28691; Ellis Bay Formation; west side of Prin- sta Bay. YPM 28692; Ellis Bay Formation; west side of Ellis Bay. YPM 28685, 28686; upper Ellis Bay Formation; reef at little cliff between Bear Cape and Cape Eagle. YPM 28694; Twenhofel’s zone 1, Ellis Bay For- mation; west side of Ellis Bay. YPM 28695-28699: Twenhofel’s zone 1, Ellis Bay Formation; Junction Cliff. YPM 28700; Twenhofel’s zone 2, Ellis Bay For- mation; coral and Beatricea zones, Lousey Cove. YPM 28701-28704; Twenhofel’s zone 2, Ellis Bay Formation; Junction Cliff. YPM 28705, 28706; Twenhofel’s zone 5, Ellis Bay Formation; Ellis Bay. YPM 28707; Twenhofel’s zone 7 (Hormotoma gi- gantea zone), Ellis Bay Formation; Ellis Bay. YPM 28708, 28709; Twenhofel’s zone 9, Ellis Bay Formation; Ellis Bay. Occurrence.—Upper Ordovician: Lower member (?Caradoc) and upper member (lower to middle Ash- gill) of the Vaureal Formation, and Ellis Bay Forma- tion (Ashgill; Gamachian); Anticosti Island, Québec, Canada. Diagnosis.—Solitary Streptelasma with major septa generally withdrawn from axis in intermediate and late stages, sometimes extending less than half the coral radius. Cardinal fossula not developed. Minor septa generally long, extending well beyond stereozone. Description of Corals.—The largest specimen ex- amined (GSC 1987g, i) is a fragment 120 mm long, with a maximum diameter of 55 mm and a diameter of 37 mm at the incomplete base. The greatest number of major septa observed is 70 at a diameter of 43 mm (YPM 28706). The corals are ceratoid to trochoid and slightly to moderately curved in early stages, and be- come cylindrical and generally straight in later stages. Prominent septal grooves and interseptal ridges are present on the epitheca. Coarse rugae are often de- veloped, and some are regularly spaced at intervals of 8 to 13 mm. Talons are present in early stages of some specimens (PI. 5, fig. 9). Depth of the calice is 30 (YPM 28706) to 60 percent of the coral length (GSC 1987, 1987c-e). The base of the calice is generally concave upward (PI. 5, fig. 10). 60 BULLETIN 314 @2 O 10 20 42 sections from 20 corals 30 4O diameter, mm Text-figure 29.—Relation between number of major septa (n) and coral diameter in Streptelasma affine (Billings, 1865). Numbers indicate frequency of a point if greater than one. Ontogeny and Internal Structures.—In early stages the major septa extend to or almost to the axis. In intermediate and late stages they may extend almost to the axis where a few septal lobes are present in some specimens (YPM 28709, Pl. 5, figs. 16-18), but are generally withdrawn (PI. 5, figs. 12, 13) and may extend less than half way to the axis (YPM 28698). The septa are commonly wavy. The number of major septa at a particular diameter is shown in Text-figure 29. The major septa are usually moderately dilated in early stages, but are non-dilated in some specimens. They are non-dilated in later stages. In small corals, the major septa rarely twist in a counterclockwise direction when viewed from the calice (YPM 28687, 28703, 28707). The cardinal sep- tum is indistinct, and a fossula is not developed. The minor septa commonly are long and extend well be- yond the stereozone. The stereozone is generally nar- row, but ranges from very narrow (YPM 28687, 28694) to broad (YPM 28705). A few thin tabellae inclined up toward the axis are present in the septal region. Complete and incomplete tabulae are developed. Within a single coral, they may vary from thin to moderately thick, and may be very closely to widely spaced. They are convex upward in the septal region and concave upward in the axial re- gion (PI. 5, fig. 10). Microstructure.—Septal fibers are distinguishable only in dilated stages. The weakly developed trabec- ulae are inclined slightly up toward the axis. In non- dilated stages, lamellae are developed in the stereo- zone. Discussion.—One specimen (GSC 1987, 1987c-e) is selected from Billings’ syntypes as the lectotype of Streptelasma affine (Billings, 1865) because it has been sectioned transversely. One of the paralecto- types designated herein (GSC 1987a) was figured by Lambe (1901, pl. 7, fig. 6, 6a), but has not been sec- tioned transversely. The source of the transverse sec- tion in Lambe’s plate 7, figure 6b is unknown. A transverse and longitudinal section of a syntype of Zaphrentis bellistriata Billings (1865) (GSC 2244, 2244a, b) indicate that it is a synonym of S. affine, as noted by Lambe (1901) and Twenhofel (1928). Specimens of S. affine having ceratoid form and septa only slightly withdrawn from the axis resemble S. rankini n. sp. from the Ashgill (Upper Ordovician) of Maine. However, S. rankini has tabulae that are much more steeply convex upward at the margins. S. affine is often similar externally and internally to S. subregulare (Savage, 1913) from the ?Gamachian (Up- per Ordovician) of Illinois and Missouri, but has a longer cardinal septum and longer minor septa, and lacks a prominent cardinal fossula. S. affine most closely resembles S$. primum (Wedekind, 1927) (see B. Neuman, 1969, pp. 11-17) from the Ashgill (Upper Ordovician) of Norway in growth form and in having short major septa and tabulae that are concave upward axially. However, the long minor septa and deep calice of S. affine are distinct. S. sp. cf. $. primum from the Upper Ordovician Centrum Formation of northeastern Greenland has more septa at a particular diameter and shorter minor septa than S. affine (see Scrutton, 1975, pp. 15, 16, pl. 2, fig. 1). Genus HELICELASMA B. Neuman, 1969 1969. Helicelasma B. Neuman, pp. 28, 29. 1981. Helicelasma B. Neuman. Elias, pp. 19, 20. Type Species (by original designation).—Helicelas- ma simplex B. Neuman (1969, pp. 29-33). Dalmani- ORDOVICIAN RUGOSE CORALS: ELIAS 61 tina beds (Upper Ordovician); Borenshult, Ostergét- land, Sweden. Discussion.—Helicelasma was proposed by B. Neuman (1969) to include solitary corals having great- ly to completely dilated major septa extending to the axis in early and intermediate ontogenetic stages. In later stages the degree of dilation is not as great and the major septa generally join into a loosely built axial structure (see B. Neuman, 1969, fig. 22). The diagnosis was based primarily on the type species. The uncertain relationship between Helicelasma and Streptelasma Hall (1847) was discussed under the latter genus. The following points suggest that Heli- celasma, Grewingkia Dybowski (1873), Leolasma Kaljo (1956), and Borelasma B. Neuman (1969) may be synonymous: . An axial region is not present in some specimens of H. randi Elias (1981), but in others it is as large as that of Grewingkia and a simple axial structure is developed. . Species of Helicelasma such as H. selectum (Billings, 1865), in which tabulae are rare and major septa are sometimes fused ax- ially into a solid structure, approach Leolasma (see B. Neuman, 1975, fig. 2). . Helicelasma includes corals having a simple axial structure and those in which major septa extend to or almost to the axis in late ontogenetic stages. Forms that have an open axial region in late stages but are otherwise similar are assigned to Borelasma (see B. Neuman, 1969, fig. 56). However, Streptelasma includes cor- als having a simple axial structure and those in which septa ex- tend to or almost to the axis, as well as forms having an open axial region in late stages (see B. Neuman, 1969, fig. 3). The boundary between Helicelasma and Borelasma therefore seems arbitrary. i) Ww Helicelasma randi Elias, 1981 Plate 6, figures 1-9 1981. Helicelasma randi Elias, pp. 20, 21, pl. 8, figs. 1-18, pl. 9, figs. 1-11. Holotype.—GSC 60735; Selkirk Member of the Red River Formation; Garson, Manitoba; Rand collection (Elias, 1981, pl. 8, figs. 1-8). Paratypes (all from Selkirk Member of the Red Riv- er Formation; Garson, Manitoba).—GSC 60730 (Elias, 1981, pl. 9, figs. 3-11), 60731, 60732, 60733 (Elias, 1981, pl. 9, figs. 1, 2). GSC 60729 (Elias, 1981, pl. 8, figs. 9-18), 60734; Rand collection. GSC 60736-60739; Elias collection. Specimens Described Herein.— SUI 57-24; probably Clermont Member, Scales Formation, Maquoketa Group; SW'%4, sec. 21 or NW44, sec. 28, Clermont Township, Fayette County, Iowa. USNM 311630-311632; Brainard Formation, Ma- quoketa Group; Sterling, Illinois. USNM 311641-311643; Brainard Formation, Ma- quoketa Group; Sterling, Illinois; Ulrich and Bassler collection. USNM 311644-311646; Brainard Formation, Ma- quoketa Group; Sterling, Illinois; Ulrich and Bassler collection. USNM 311633, 311634; Brainard Formation, Ma- quoketa Group; SE'%4, SE'%4, sec. 35, T9IN, R6W, Clayton County, Iowa; Gerk collection. SIU 4200, 4201; Orchard Creek Member of the Scales Formation, Maquoketa Group; bank of Missis- sippi River, 1.6 km north of Thebes, SE, sec. 5, T15S, R3W, Alexander County, Illinois; Guensburg collection. Occurrence.—Upper Middle (?) and Upper Ordo- vician: Selkirk Member of the Red River Formation (upper Middle or Upper Ordovician); Garson, Mani- toba, Canada. Probably Clermont Member, Scales Formation (Richmondian), Maquoketa Group; Fayette County, Iowa, U.S.A. Orchard Creek Member of the Scales Formation (Richmondian), Maquoketa Group; Alexander County, Illinois, U.S.A. Brainard Forma- tion (Richmondian), Maquoketa Group; Clayton County, Iowa, and Sterling, Illinois, U.S.A. Diagnosis.—Helicelasma usually with simple axial structure of a few septal lobes and lamellae in later stages. Dilation of major septa slight to complete in early stage, commonly producing a solid axis or a ring around axial region. Septa non-dilated in late stage. Cardinal septum generally long and thin, cardinal fos- sula moderately broad. Tabulae convex upward if de- veloped. Description of Corals.—The largest specimen ex- amined (USNM 311641) has a length of 63 mm and diameter of 23 mm immediately below the calice where 40 major septa are present. The corals are trochoid, and straight to slightly curved. Septal grooves and in- terseptal ridges are present on the epitheca. Depth of the calice is 30 percent of the coral length (USNM 311644). The calicular boss is highly convex (USNM 311644, Pl. 6, fig. 7). Ontogeny and Internal Structures.—In early stages the major septa extend to or almost to the axis. In intermediate and late stages a few septal lobes and lamellae develop in the axial region. Groups of two or more major septa commonly converge near the axis. The number of major septa at a particular diameter is shown in Text-figure 30. In early stages, septal dilation is complete (USNM 311641) to moderate (USNM 311630). Dilation near the axis produces a ring around the axial region in some specimens (USNM 311630, Pl. 6, figs. 3, 4; SIU 4200). The cardinal septum is long and thinner than the other major septa. The cardinal fossula is moderately broad. Minor septa are confined to or extend a short distance beyond the moderately broad stereozone. In later stages the tabulae are com- plete, relatively widely spaced, and moderately con- vex upward (PI. 6, fig. 7). Microstructure.—The microstructure is unknown because of poor preservation. Discussion.—These specimens from the Maquoketa Group of Iowa and Illinois cannot be distinguished morphologically from Helicelasma randi Elias (1981) of the Selkirk Member, Red River Formation, in southern Manitoba. The number of major septa at a particular diameter is similar in both units, although corals from the Maquoketa tend to have slightly lower values (Text-fig. 30). The specimen from Clermont Township, Iowa, probably from the Clermont Member of the Scales Formation (PI. 6, fig. 8), has a larger axial region than those from the Brainard Formation (Pl. 6, figs. 4, 6). The relationship of H. randi with other species of the genus was discussed by Elias (1981, p. 21). H. selectum (Billings, 1865) from the Ashgill (Upper Or- dovician) of Québec is similar in the latest ontogenetic stages, when a small axial structure consisting of a few dilated septal lobes and lamellae is present, and the 4O : e2e : ee g e ul baw Vind : x exe gies D@ e x Maquoketa Gp. Cy @ Selkirk Mbr., R BULLETIN 314 thin cardinal septum is located in a moderately broad fossula. However, H. selectum differs in having com- pletely dilated septa except in late stages immediately below the calice where the cardinal septum commonly is short, and in generally possessing fewer septa than H. randi at a particular coral diameter (Text-figs. 30, 31). Helicelasma selectum (Billings, 1865) Plate 6, figures 10-20 1865. Petraia selecta Billings, p. 429 [partim]. 1866. Petraia selecta Billings. Billings, p. 7 [partim]. 1901. Streptelasma selectum (Billings). Lambe, p. 113 [partim], non pl. 6, fig. 8, 8a. 1928. Streptelasma selectum (Billings). Twenhofel, p. 113 [partim]. Lectotype (designated herein).—GSC 1989a, b; up- per member, about 27 to 30 m below top of Vauréal Formation; west end lighthouse, Anticosti Island, Québec; J. Richardson collection, 1856 (PI. 6, figs. 10, iL). Paralectotypes (designated herein).—GSC 1989, 19892; GSC 1989c, d; GSC 1989f; upper member, about 27 to 30 m below top of Vauréal Formation; west end lighthouse, Anticosti Island, Québec; J. e e e e e @2 © e @2 e.° oe? e x x e ex 9 sections from 7 corals ” ed River Fm. 46 10 2@ 30 diameter, mm Text-figure 30.—Relation between number of major septa (n) and coral diameter in Helicelasma randi Elias (1981) from the Selkirk Member, Red River Formation, southern Manitoba (see Elias, 1981, fig. 13b) and the Maquoketa Group. Numbers indicate frequency of a point if greater than one. ORDOVICIAN RUGOSE CoRALs: ELIAS 63 Richardson collection, 1856. Other Specimens .— (All from Twenhofel collection, Anticosti Island, Québec, unless otherwise stated.) YPM 28710; upper member (English Head facies) of the Vaureal Formation; English Head. YPM 28711; upper member (English Head facies) of the Vauréal Formation; West Bay. YPM 28712; Ellis Bay Formation; Cape James. YPM 28713; Ellis Bay Formation; zone 21 of Twen- hofel’s Vauréal River section. YPM 28714; basal unit, Ellis Bay Formation; zone 10 of Twenhofel’s Vauréal River section. YPM 28715; Twenhofel’s zone 2, Ellis Bay For- mation; coral and Beatricea zones, Lousey Cove. USNM 311636, 311637, and YPM 28716; Stenopa- reia faunal zone, White Head Formation; Grande Coupe, 2.4 km northwest of Percé, Québec. Occurrence.—Upper Ordovician: Upper member (lower to middle Ashgill) of the Vauréal Formation, and Ellis Bay Formation (Ashgill; Gamachian); Anti- costi Island, Québec, Canada. White Head Formation (lower to middle Ashgill); Percé, Québec, Canada. Diagnosis.—Helicelasma with small axial structure of a few dilated septal lobes and lamellae in late stage. Septa generally completely dilated until immediately below calice in late stage, where dilation is slight to great. Cardinal septum thin and commonly short in late stage, cardinal fossula moderately broad. Tabulae rare. Description of Corals.—The longest specimen ob- served (YPM 28712) is incomplete, and has a length of 50 mm. The broadest specimen (YPM 28715) has a diameter of 27 mm. The maximum number of septa observed is 44 at a diameter of 25 mm (USNM 311637). The corals are trochoid and slightly curved. Weakly developed septal grooves and interseptal ridges are preserved on the epitheca of some specimens (GSC 1989, 19892). Depth of the calice is 40 percent of the coral length (GSC 1989a, b; GSC 1989c, d). A calicular boss is not developed. Ontogeny and Internal Structures.—In early stages the major septa extend to the axis. In intermediate stages, a few completely dilated septal lobes are pres- ent at the axis, and in late stages a few dilated septal lamellae may develop in the small axial structure. The number of major septa at a particular diameter is shown in Text-figure 31. The septa are generally com- pletely dilated except in late stages immediately below the calice, where septa are slightly (USNM 311637) to more commonly greatly dilated. In late stages the car- dinal septum is thin and generally very short. The car- dinal fossula is moderately broad. The minor septa are moderately long, and some extend a short distance beyond the moderately broad stereozone in slightly dilated late stages. A few tabulae are present in some specimens (GSC 1989a, b). Microstructure.—Septal fibers are well developed and the trabeculae are slightly inclined up toward the axis. Lamellae commonly are present in the stereo- zone. Discussion.—Specimens collected in 1856 by Rich- ardson at the west end lighthouse on Anticosti Island (GSC 1989, 1989a—n) were probably used by Billings in his original description of Petraia selecta. They are considered to be syntypes. However, two species are represented in this collection. One is Grewingkia pul- chella (Billings, 1865). The other is considered to be Helicelasma selectum (Billings, 1865), for which a lec- totype and paralectotypes are herein selected. Bil- lings’ Petraia pulchella was considered a synonym of P. selecta by Lambe (1901) and Twenhofel (1928), but two species are definitely involved. In the latest ontogenetic stages, H. selectum resem- bles H. randi Elias (1981) from the upper Middle or Upper Ordovician of southern Manitoba and Rich- mondian (Upper Ordovician) of Iowa and Illinois. Both species have a small axial structure of a few di- lated septal lobes and lamellae, and the thin cardinal septum is located in a moderately broad fossula. How- ever, H. selectum is distinct in having completely di- lated septa except in late stages immediately below the calice where the cardinal septum is usually short, and in commonly possessing fewer septa than H. randi at a particular diameter (Text-figs. 30, 31). Genus DEIRACORALLIUM Nelson, 1963 1963. Deiracorallium Nelson, p. 37. 1981. Deiracorallium Nelson. Nelson, pp. 52, 53. 1981. Deiracorallium Nelson. Elias, pp. 21, 22. Type species (by original designation).—Deiracor- allium manitobense Nelson (1963, pp. 37, 38). Church- 40 . x Percé 2 sections from 1 coral(s) ® Anticosti Is. 8 am eS) O 10 20 diameter, mm Text-figure 31.—Relation between number of major septa (n) and coral diameter in Helicelasma selectum (Billings, 1865). 64 BULLETIN 314 ill River Group (Upper Ordovician); Hudson Bay Lowland, northern Manitoba, Canada. Discussion.—Deiracorallium was proposed by Nel- son (1963) to include compressed solitary corals hav- ing a markedly angulate convex cardinal side and greatly dilated major septa that extend to the axis without twisting. This diagnosis was based on the small type species D. manitobense Nelson (1963). It may be conspecific with D. angulatum (Billings, 1862) of Anticosti Island, Québec, a possibility recognized by Nelson (1963, p. 38; 1981, p. 54) and discussed under the species herein. D. giganteum Nelson (1963) is of moderate size and has major septa that twist in the axial region. D. harveyi Nelson (1981) and D. de- licatum Elias (1981) attain moderately large size and in later ontogenetic stages have slightly dilated major septa and a small axial structure of septal lobes and lamellae. Therefore, the genus was expanded by Nel- son (1981) and Elias (1981) to include compressed forms with a small axial structure. The following points suggest that Deiracorallium, Grewingkia Dybowski (1873), and Leolasma Kaljo (1956) are closely related and possibly synonymous: 1. Large species of Deiracorallium such as D. delicatum and D. harveyi differ from Grewingkia in that the corals are compressed and the axial structure is smaller. However, G. robusta (Whit- eaves, 1896) and G. haysii (Meek, 1865) are sometimes com- pressed, and both D. delicatum and G. robusta can be triangulate to slightly trilobate (see Elias, 1981). The significance of external form as a diagnostic generic trait is therefore questionable. Vari- ability in complexity and size of the axial structure in Grewingkia is great, as will be discussed under that genus. . Except for external form, small species such as D. angulatum resemble Leolasma, which is circular in cross-section (see B. Neuman, 1975, fig. 2). The major septa are greatly to completely dilated until immediately below the calice where dilation de- creases except around the axis, and tabulae are rare or absent. Nm Deiracorallium angulatum (Billings, 1862) Plate 6, figures 21-33 1862. Petraia angulata Billings, p. 103, fig. 90a, 90b. 1901. Streptelasma angulatum (Billings). Lambe, p. 112. 1928. Streptelasma angulatum (Billings). Twenhofel, pp. 111, 112, plass figs: 1937. ‘‘Streptelasma angulatum (Billings)’’. Cox, p. 4, pl. 1, fig. 5. 1943. [?] Streptelasma trilobatum (Whiteaves). Okulitch, pl. 1, figs. 13, 14. 1959b. [?] “‘Streptelasma angulatum (Billings)’’. Nelson, pl. 4, fig. 2a, 2b. 1963. [?] Deiracorallium manitobense Nelson, pp. 37, 38, pl. 13, figs. 1, 2a, 2b. 1963. [?] Deiracorallium manitobense var. churchillense Nelson, p. 38, pl. 13, fig. 3a, 3b. 1981. [?] Deiracorallium manitobense Nelson. Nelson, pp. 53, 54, pl. 8, figs. 13, 14. 1981. [?] Deiracorallium manitobense churchillense Nelson. Nel- son, p. 54, pl. 8, fig. 12. Lectotype (listed as holotype by Twenhofel, 1928).—GSC 1984, 1984a; upper member, about 30+ m below top of Vauréal Formation; west end camp, Anticosti Island, Québec; J. Richardson collection, 1856 (Twenhofel, 1928, pl. 3, fig. 5; Cox, 1937, pl. 1, fig. 5). Other Specimens.— (All from Anticosti Island, Québec.) GSC 66592-66619; upper member, 60+ m below top of Vauréal Formation; GSC locality 84419, main high- way section on upper elevation east of Potatoe River crossing; Bolton collection. YPM 28717-28720; Twenhofel’s zone 5, upper member of the Vauréal Formation; Twenhofel collec- tion. Occurrence.—Upper Ordovician (lower to middle Ashgill): Upper member of the Vauréal Formation; Anticosti Island, Québec, Canada. Diagnosis.—Deiracorallium with major septa ex- tending to axis throughout ontogeny. Septal dilation great to complete until immediately below calice, where it decreases except around axis. Cardinal sep- tum short and thin in latest stage. Tabulae rare. Description of Corals.—The largest specimen ex- amined has a length of 23 mm. The maximum number of major septa observed is 36 at a height of 9 mm (GSC 66593). The corals are ceratoid to trochoid. They are slightly to moderately curved, greatly compressed, and triangulate in early stages. Later, curvature de- creases, coral expansion decreases or ceases, and compression and triangulation decrease. Weakly de- veloped septal grooves and interseptal ridges are pres- ent on the epitheca. Depth of the calice is 30 percent of the coral length. A calicular boss is not developed. Ontogeny and Internal Structures.—The major sep- ta extend to or almost to the axis throughout ontogeny. The number of major septa at a particular height is shown in Text-figure 32. As would be expected, tro- choid corals have more septa at a particular height than do ceratoid forms. The septa are greatly to com- pletely dilated until immediately below the calice, where dilation decreases except around the axis. The cardinal septum is short and thin in late stages, and the cardinal fossula is narrow. In late stages immedi- ately below the calice, the length of minor septa varies from those confined to the moderately broad stereo- zone (GSC 66592, Pl. 6, fig. 24) to those extending well beyond it (GSC 66593, PI. 6, fig. 31). Tabulae are rare in late stages. Microstructure.—Septal fibers are well developed, and the trabeculae are slightly inclined up toward the axis. Lamellae are not present in the stereozone. Discussion.—Billings’ (1862) original description of Petraia angulata was based on three syntypes, one of ORDOVICIAN RUGOSE CORALS: ELIAS 65 which was figured. Twenhofel (1928) listed and figured one specimen as the holotype (GSC 1984), and listed a paratype (GSC 1984a). However, the latter is a thin section of the former. Cox (1937) listed and figured this thin section as the holotype, but it is not the orig- inal of Billings’ figure, as he stated. Only one syntype of this species is known (GSC 1984, 1984a). It is the lectotype of Deiracorallium angulatum (Billings, 1862). Specimens of Deiracorallium in the Upper Ordovi- cian Stony Mountain Formation of southern Manitoba were assigned to Streptelasma trilobatum by Okulitch (1943), to “‘S. angulatum’’ by Nelson (1959b), and to D. manitobense by Nelson (1963, 1981). Similar spec- imens from the correlative Caution Creek and Chasm Creek Formations of northern Manitoba were assigned to D. manitobense and D. manitobense churchillense by Nelson (1963, 1981). These corals from Manitoba may be conspecific with D. angulatum, a possibility recognized by Nelson (1963, p. 38; 1981, p. 54). All have similar numbers of septa at a particular height (Text-fig. 32). Definite assignment must await further sectioning and study of the forms from Manitoba. Genus GREWINGKIA Dybowski, 1873 1873. Grewingkia Dybowski, p. 384. 1969. Grewingkia Dybowski. B. Neuman, pp. 33-36. 1974. Grewingkia Dybowski. McLean, pp. 42-44. 1981. Grewingkia Dybowski. Nelson, p. 41. 1981. Grewingkia Dybowski. Elias, pp. 11, 12 40 n LE 20, Type Species (by subsequent designation).—Clisio- phyllum buceros Eichwald (1856, p. 108); selected by Sherzer (1891, p. 284; see Kaljo, 1961, p. 53). Type stratum and locality unknown (see Kaljo, 1961, p. 54). Discussion.—Until B. Neuman’s (1969) examina- tion of variability within Grewingkia, diagnoses of the genus were based almost entirely on characteristics of the type species alone. The degree of septal dilation and nature of the axial structure are the most variable morphologic features (see B. Neuman, 1969, fig. 27). As presently understood, the genus includes species such as G. penobscotensis n. sp. and G. anguinea (Scheffen, 1933) that have slightly dilated major septa in early ontogenetic stages, and G. rustica (Billings, 1858a) in which dilation is complete in early stages and great even in later stages. In general, the axial struc- ture of Grewingkia is relatively large and consists of numerous septal lobes and lamellae in later stages. The uncertain relationships of Grewingkia, Strep- telasma Hall (1847), Helicelasma B. Neuman (1969), and Deiracorallium Nelson (1963) were discussed un- der the latter three genera. The following points sug- gest that the sequence Borelasma B. Neuman (1969) — Helicelasma — Grewingkia = Lobocorallium Nel- son (1963) is gradational: 1. The single species G. canadensis (Billings, 1862) is highly vari- able and includes corals having an open axial region as in Bo- relasma (see B. Neuman, 1969, fig. 56), those resembling Heli- trochoid coral \ ceratoid O 15 height, mm Text-figure 32.—Relation between number of major septa (n) and coral height, and coral form in species of Deiracorallium. a-d. GSC 66592-66595, D. angulatum (Billings, 1862), upper member, Vauréal Formation, Anticosti Island, Québec. e. GSC 10846, paratype of D. manitobense Nelson (1963), member No. 1, Caution Creek Formation, northern Manitoba. f. GSC 10847, holotype of D. manitobense churchillense Nelson (1963), member No. 1, Chasm Creek Formation, northern Manitoba. g, h. GSC 66620, 66621, Deiracorallium sp., Gunn Member, Stony Mountain Formation, Stony Mountain, Manitoba. 66 BULLETIN 314 celasma in having major septa that extend to the axis (see B. Neuman, 1969, fig. 22), and forms with simple to complex axial structures in late ontogenetic stages, as is characteristic of Grew- ingkia. 2. The following continuous morphologic sequence between Grew- ingkia and Lobocorallium is recognized, and involves an increase in the degree of trilobation and septal dilation, and a decrease in the number of tabulae: G. robusta (Whiteaves, 1896) > G. haysii (Meek, 1865) > L. trilobatum vaurealense (Twenhofel, 1928) > L. trilobatum trilobatum (Whiteaves, 1895) [see Elias (1981), and Lobocorallium herein]. Grewingkia canadensis (Billings, 1862) Plate 7, figures 1-21; Plate 8, figures 1-30; Plate 9, figures 1-21; Plate 10, figures 1-28 1851. Streptelasma corniculum Hall. Milne-Edwards and Haime, pp. 398, 399 [partim], pl. 7, fig. 4, 4a, 4b. 1862. Zaphrentis canadensis Billings, pp. 105, 106, fig. 93a—c. 1863. Petraia canadensis (Billings). Geological Survey of Canada, fig. 205. 187Sa. Streptelasma corniculum Hall. Nicholson, pp. 26, 27 (partim]. 1875b. Streptelasma corniculum Hall. Nicholson, pp. 218, 219 [partim]. 1876. Streptelasma corniculum Hall. Nicholson, p. 94, pl. 5, fig. 15, 15a. 1876. Streptelasma corniculum Hall. Rominger, pp. 142, 143 [partim], pl. 51, upper tier [partim). 1882. Streptelasma corniculum Hall. Hall, p. 376 [partim], pl. 51, figs. 24. 1901. Streptelasma rusticum (Billings). Lambe, pp. 110-112 [partim], non pl. 7, figs. 2, 2a, 3. 1908. Streptelasma rusticum (Billings). Cumings, pp. 708, 709 [partim], pl. 2, fig. 2, 2a, 2b. 1909. Streptelasma vagans Foerste, pp. 305, 306, pl. 11, fig. la—c. 1909. Streptelasma insolitum Foerste, p. 306, pl. 10, fig. 3. 1909. Streptelasma dispandum Foerste, p. 307, pl. 9, fig. 4a, 4b. 1924. Streptelasma rusticum (Billings). Foerste, pp. 65, 66 [partim], pl. 1, figs. la-c, 2a—c, pl. 2, fig. 6a-c. 1924. Streptelasma dispandum Foerste. Foerste, pp. 66, 67, pl. 2, fig. 4. 1932. Streptelasma rusticum (Billings). Bassler, pl. 24, figs. 16, 17. 1937. Streptelasma rusticum (Billings). Cox, pp. 11-13 [partim], pl. 2, figs. 11, 12a—c, 13a—d. 1948. Streptelasma rusticum (Billings). C. W. Wilson, pl. 19, figs. PAO Pile 1949. Streptelasma rusticum (Billings). C. W. Wilson, pl. 19, figs. 26, 27. 1963. Streptelasma arcticum drummondense Stumm, p. 27, pl. 2, figs. 4-7. 1964. Grewingkia rustica (Billings). Liberty, pl. 6, fig. 8. 1967. Grewingkia rustica (Billings). Oliver in Simmons and Oliver, pp. 9, 10. 1967. “Streptelasma’’ spp. A-E and °“‘S.”’ angulatum (Billings). Oliver in Simmons and Oliver, p. 10. 1972. Grewingkia rustica (Billings). Bolton and Copeland, pl. B, figs. 9, 11. 1978. Grewingkia sp. Copper, pl. 6, figs. 3, 4. Lectotype (designated herein).—GSC 1983h, i; up- per member of the Georgian Bay Formation; Drum- mond Island, Michigan; A. Murray collection, 1847 (Billings, 1862, fig. 93b; Pl. 10, figs. 9-11). Paralectotypes (designated herein).—GSC 1983, 1983a; GSC 1983, c, e (Billings, 1862, fig. 93c; Lib- erty, 1964, pl. 6, fig. 8; Bolton and Copeland, 1972, pl. B, fig. 11); GSC 1983d; GSC 1983f, g; upper member of the Georgian Bay Formation; Drummond Island, Michigan; A. Murray collection, 1847. Other Specimens.— UCGM 45153-45500; Richmond Group; Cincinnati Arch region of Ohio, Indiana, and Kentucky (see Text- fig. 3 for stratigraphic positions and locations); Elias collection. USNM 311626, 311627; ‘‘Waynesville”’ strata (base of Clarksville beds) of the Richmond Group; near Clarksville, Ohio. USNM 70487 (4 specimens); ‘‘Waynesville”’ strata (lower | m of Clarksville beds) of the Richmond Group; Stony Hollow, Clarksville, Ohio. USNM 78749 (syntype of S. vagans); “Liberty” strata of the Richmond Group; Tate’s Hill, Dayton, Ohio. USNM 84871 (2 specimens); “‘Liberty’’ or **White- water’ strata of the Richmond Group; Tate’s Hill, Dayton, Ohio. USNM 78742 (5S syntypes of S. dispandum); ‘‘Waynesville’’ strata (Blanchester beds) of the Rich- mond Group; Moore’s Hill, Indiana. USNM 84870 (holotype of S. insolitum); **White- water’ strata of the Richmond Group; southeast of Westport, Indiana. USNM 9719 (9 specimens); *‘Waynesville”’ strata of the Richmond Group; railroad cut, Madison, Indiana. USNM_ 15587; *‘Whitewater”’ strata of the Rich- mond Group; Connersville, Indiana. USNM 311663-311716; Otter Creek coral bed, Preachersville Member, Drakes Formation (see Sim- mons and Oliver, 1967): USNM 311663-311666, USGS locality 4662-CO, Lancaster Quadrangle, Lin- coln County, Kentucky; USNM 311667-311692, USGS locality D1370-CO, Richmond North Quadran- gle, Madison County, Kentucky; USNM 311693, USGS locality 5308-CO, Union City Quadrangle, Madison County, Kentucky; USNM 311694—311704, USGS locality 4468-CO, Palmer Quadrangle, Estill County, Kentucky; USNM 311705-311710, USGS lo- cality 4545-CO, Palmer Quadrangle, Madison County, Kentucky; USNM 311711-311716, USGS locality 4760-CO, Palmer Quadrangle, Clark County, Ken- tucky. UCGM 45501-45536; Richmond Group; Goodletts- ville-Gallatin area of Tennessee (see Text-fig. 3 for stratigraphic positions and locations); Elias collection. USNM 102371 (7 specimens); Arnheim Formation ORDOVICIAN RUGOSE CORALS: ELIAS 67 (Rhynchotrema dentatum bed, middle division of Richmond Group); 6.4 km northeast of Goodlettsville, Tennessee. USNM 42512 (21 specimens); 6.4 km northeast of Goodlettsville, Tennessee. USNM 311647-311652; Bassler’s bed 5, Richmond Group; near Bakers, Tennessee. USNM 80609; Arnheim Formation; near Bakers, Tennessee. USNM 42515 (13 specimens); Arnheim Formation; 0.8 km south of Dismukes, Sumner County, Tennes- see. USNM 311653; colonial coral bed at top of Maquo- keta Group; NW, sec. 17, T27N, R24E, Little Stur- geon Bay, Wisconsin; Ulrich collection. USNM 311654-311659 (G. cf. G. canadensis); co- lonial coral bed at top of Maquoketa Shale; Little Stur- geon Bay, Wisconsin; Ulrich and Mesler collection. UCGM 45537-45562, 45612; upper Meaford beds, upper member of the Georgian Bay Formation; Drum- mond Island, Michigan (see Text-fig. 18 for strati- graphic positions and locations); Elias collection. UMMP 26927, 45353, 45354 (holotype and para- types, respectively, of S. arcticum drummondense),; upper Meaford beds, upper member of the Georgian Bay Formation; south side of Potaganissing Bay, Poe Point, Drummond Island, Michigan; Hussey collec- tion. UCGM 45563-45591; Meaford beds, upper member of the Georgian Bay Formation; Manitoulin Island, Ontario (see Text-fig. 18 for stratigraphic positions and locations); Elias collection. GSC 66622-66634; upper Wekwemikongsing beds, lower member of the Georgian Bay Formation; local- ity M75, Manitoulin Island, Ontario (see Text-fig. 18 for stratigraphic position and location). GSC 66637-66649; Meaford beds, upper member of the Georgian Bay Formation; locality M6la, Manitou- lin Island, Ontario (see Text-fig. 18 for stratigraphic position and location). GSC 8530, 8530a—c, e-j (10 specimens); Meaford beds, upper member of the Georgian Bay Formation; gully north of lighthouse, Manitowaning, Manitoulin Island, Ontario; Foerste collection. GSC 8529, 8529b-d (4 specimens); GSC 8528, 8528a—-d (5 specimens); GSC 8573a-c (3 specimens); GSC 66589; Meaford beds, upper member of the Geor- gian Bay Formation; GSC locality 6259, Clay Cliffs, Manitoulin Island, Ontario; Foerste collection. GSC 1982, 1982a; GSC 1982b, c; GSC 1982d, e: GSC 1982f, g; GSC 1982i; GSC 1982k, 1; Meaford beds, upper member of the Georgian Bay Formation; Cape Smith, Manitoulin Island, Ontario; R. Bell col- lection, 1859. GSC 8531; upper Georgian Bay Formation; 3.2 km northwest of Meaford on road to Cape Rich, Ontario; Foerste collection. Occurrence.—Upper Ordovician (Richmondian): ““Waynesville’’ strata to top of Richmond Group; Cin- cinnati Arch region of Ohio, Indiana, and Kentucky, U.S.A. Throughout the Richmond Group; Goodletts- ville-Gallatin area of Tennessee, U.S.A. Meaford beds, upper member of the Georgian Bay Formation; Drummond Island, Michigan, U.S.A. Top of lower member (Wekwemikongsing beds), and Meaford beds of upper member, Georgian Bay Formation; Manitou- lin Island, Ontario, Canada. Top of Georgian Bay For- mation; Meaford, Ontario, Canada. Top of Maquoketa Group; Little Sturgeon Bay, Wisconsin, U.S.A. Diagnosis.—Axial region highly variable in late stage, ranging from very complex axial structure with many septal lobes and lamellae, to simple structure with only a few septal lobes, to open axial region lack- ing septal elements—moderately complex axial struc- ture with septal lobes and lamellae is most common. Major septa completely dilated in early stage, greatly to completely dilated in intermediate stage, and non- dilated to slightly dilated in late stage. Cardinal and counter septa generally distinct, longer than the other septa throughout ontogeny and commonly with greatly dilated lobes in intermediate stage. Description of Corals.—The corals can attain lengths in excess of 130 mm, and diameters greater than 40 mm. The length of specimens is shown in Text- figure 6 (see discussion under ‘‘Cincinnati Arch Re- gion’). The corals vary from ceratoid to trochoid in early stages, and commonly become cylindrical in late stages. They are generally slightly curved in early to intermediate stages and are straight in late stages. Moderately curved specimens are uncommon. Wells (1970, p. 9) reported about 412 daily growth lines per year for a well preserved coral from Ohio that prob- ably belongs to this species. Septal grooves and inter- septal ridges are preserved on the epitheca of some specimens. Corals in lateral contact are very rare (USNM 15587, Pl. 9, fig. 17; UCGM 45307, 45438, 45533, 45577). Asexual increase has not been dem- onstrated in these cases. Depth of the calice common- ly is about 35 percent of the coral length, but varies from 30 to 50 percent. The calicular boss is moderately convex when an axial structure is developed (Pl. 9, fig. 19s). Ontogeny and Internal Structures.—In early stages the major septa extend to or almost to the axis. In 68 intermediate stages the small axial structure is com- posed of a few greatly dilated septal lobes, and the cardinal and counter septal lobes are often especially prominent (for example, Pl. 9, fig. 12). In late stages the axial region is highly variable. The axial structure is generally of moderate size and complexity, consist- ing of septal lobes and lamellae, but it varies from very complex with many fine septal lamellae to simple with only a few septal lobes. Septal elements are complete- ly lacking in some specimens, resulting in an open axial region (Pl. 7, figs. 1-21; Text-fig. 12). The number of major septa at a particular diameter is shown in Text-figure 33. The major septa are com- pletely dilated in early stages, greatly to completely dilated in intermediate stages, and non-dilated to slightly dilated in late stages. The cardinal and counter septa commonly are distinct in being longer than the other septa throughout ontogeny (for example, Pl. 8, figs. 26-29, Pl. 7, fig. 12). The cardinal fossula in late stages is narrow and expands at the axial region. The minor septa are generally confined to the moderately broad stereozone in late stages. Tabellae are present in the septal region in incom- 60 2B apes . 2 3G BAG MiG rece eee coe 22s Bee n40 eget ROR oT - if 2 a oe a $ BULLETIN 314 pletely dilated stages (for example, Pl. 8, fig. 30), and in the cardinal fossula. They are steeply to moderately inclined up toward the axis in intermediate stages and become less steeply inclined with increased height in the coral. The tabulae in the axial region are mostly complete and generally moderately spaced. In inter- mediate stages they are moderately to highly convex upward, and in late stages are commonly moderately convex. Microstructure.—The major septa are clearly fi- brous, especially when dilated. Trabeculae are in- clined slightly up toward the axis. The stereozone in incompletely dilated sections is composed of lamellae. The epitheca consists of small groups of fibers that commonly are oriented perpendicular to the exterior surface. Discussion.—The syntypes of Zaphrentis canaden- sis are from Drummond Island, where corals are un- fortunately not as well preserved as elsewhere in the Richmond Province. However, these and other spec- imens from Drummond Island are indistinguishable from specimens at Manitoulin Island, the Cincinnati Arch region, and northern Tennessee. One specimen +2 , ae Hee: c : 5 2 go eptisdiss BA mise 2:2 2 ae? 22 Bas \ 5 °2 * 6 « 5e 3-32 oe 2 * 03 43, 6. +2 tae 5 1) Sy eDegue < co oO 2 -O 2 513 sections from 263 corals 10 20 diameter, mm 30 40 Text-figure 33.—Relation between number of major septa (n) and coral diameter in Grewingkia canadensis (Billings, 1862) from the entire Richmond Group, Cincinnati Arch region. Numbers indicate frequency of a point if greater than one. Curve determined by inspection using class averages. 1. = USNM 78749a [syntype of Streptelasma vagans Foerste (1909)], **Liberty’’ strata, Dayton, Ohio. 1 = USNM 78742a [syntype of S. dispandum Foerste (1909)], ‘‘Waynesville’’ strata, Moore’s Hill, Indiana. O = USNM 84870a, b [holotype of S. insolitum Foerste (1909)], *‘Whitewater’’ strata, Westport, Indiana. ORDOVICIAN RUGOSE CORALS: ELIAS 69 (GSC 1983h, i) from Billings’ syntypes is designated as the lectotype of Grewingkia canadensis (Billings, 1862) because it was figured in the original description and transverse sections have been prepared. The Late Ordovician solitary corals from Drum- mond Island were assigned to Streptelasma cornicu- lum by Nicholson (1875b) and Rominger (1876), to S. rusticum by Lambe (1901) and Cox (1937), and to G. rustica by Liberty (1964) and Bolton and Copeland (1972). Solitary corals from Manitoulin Island were assigned to S$. corniculum by Nicholson (1875a), S. rusticum by Lambe (1901), Foerste (1924), and Cox (1937), and G. rustica by Bolton and Copeland (1972). All these corals are G. canadensis. Stumm (1963) de- scribed §. arcticum drummondense from Drummond and Manitoulin Islands. The holotype, which has been sectioned (PI. 10, figs. 15-17), and figured paratypes are G. canadensis. The large solitary corals from the Cincinnati Arch region were assigned to §. corniculum by Milne-Edwards and Haime (1851), Nicholson (1875b, 1876), Rominger (1876), and Hall (1882), and to S. rusticum by Cumings (1908) and Cox (1937). Foerste (1909) described S$. vagans, S. insolitum, and S. dispandum, distinguishing them primarily on the basis of external form. In 1924, he synonymized S. vagans with S. rusticum and reported S$. dispandum from Manitoulin Island. His types have been sec- tioned, and are G. canadensis (Pl. 9, figs. 13-16). Oliver (in Simmons and Oliver, 1967) reported G. rus- tica, ““Streptelasma”’ spp. A—-E and “‘S.”’ angulatum. These specimens have been examined, and represent various growth stages and variations of G. canadensis. Bassler (1932) and C. W. Wilson (1948, 1949) assigned solitary corals from northern Tennessee to S. rusti- cum. These are G. canadensis. Foerste (1924) identi- fied a specimen from Meaford, Ontario, as S. rusti- cum. This coral has been sectioned and is G. canadensis (Pl. 10, fig. 28). Specimens from Little Sturgeon Bay are silicified and poorly preserved, but one (USNM 311653) can be assigned to G. canadensis (Pl. 10, fig. 8). The degree of axial region variation in later onto- genetic stages within G. canadensis spans the genera Borelasma, Helicelasma, and Grewingkia as they are presently defined. The species is referred to Grewing- kia because the majority of corals have a moderately complex axial structure characteristic of that genus. G. rustica (Billings, 1858a), known from the Richmond Group at Lake St. John, Québec, and Manitoulin Is- land, Ontario, is similar to G. canadensis in external form, and the two species may be related. G. cana- densis is distinguished by its cardinal and counter sep- ta that commonly are longer than the other septa throughout ontogeny and have greatly dilated lobes in intermediate stages. In G. rustica, the major septa generally form a counterclockwise whorl in early to intermediate stages, and septal dilation is complete to great until immediately below the calice in late stages, where dilation decreases and a complex axial structure develops. The number of major septa at a particular diameter for G. rustica is at the low end of the range of values for G. canadensis (Text-figs. 33, 35). G. can- adensis resembles species of Grewingkia from the continental interior of the Red River—Stony Mountain Province in having well developed tabellae in the sep- tal region (see Elias, 1981). Grewingkia deltensis n. sp. Plate 11, figures I-11 1918. Streptelasma rusticum (Billings). Foerste, p. 99, pl. 4, fig. 1. 1963. Streptelasma rusticum (Billings). Stumm, pp. 26, 27 [partim], pl. 2, figs. 1-3, non pl. 2, figs. 8-10. Derivation of Name.—The specific name is derived from Delta County, Michigan, where the species oc- curs. Holotype. —UCGM 45602; Ogontz Member of the Stonington Formation; locality 17b, Delta County, Michigan; Elias collection (Pl. 11, figs. 1-8). Paratypes.—UMMP 26911; Bay de Noc Member of the Stonington Formation; locality 175, Delta County, Michigan (Stumm, 1963, pl. 2, figs. 1-3). UCGM 45593-45595, 45596 (Pl. 11, figs. 9-11), 45597-45601, 45603, 45604; Ogontz Member of the Stonington For- mation; locality 17b, Delta County, Michigan; Elias collection. Occurrence.—Upper Ordovician (Richmondian): Bay de Noc and Ogontz Members of the Stonington Formation; Delta County, Michigan, U.S.A. Diagnosis.—Grewingkia with moderately complex axial structure of septal lobes and lamellae in late stage. Major septa almost completely dilated in early stage and non-dilated in late stage. Cardinal septum becomes short, cardinal fossula prominent and broad in late stage. Tabulae slightly convex upward within septal and axial regions but concave upward at junc- tion of the two regions. Description of Corals.—The longest specimen ex- amined (UCGM 45604) has a length of 85 mm and diameter of 33 mm immediately below the calice where 59 major septa are present. Another specimen (UMMP 26911) is 81 mm long and has a diameter of 37 mm immediately below the calice where 62 major septa are present. The corals are trochoid and moderately curved. Septal grooves and interseptal ridges are pres- ent on the epitheca (UCGM 45594). Depth of the calice is 30 percent of the coral length (UMMP 26911; 70 BULLETIN 314 UCGM 45602, 45604). The calicular boss is slightly convex (UCGM 45602, Pl. 11, fig. 7). Ontogeny and Internal Structures.—Near the tip, some major septa extend to the axis. In intermediate stages a few long septal lobes arising primarily from septa on the cardinal side extend to the axis. In late stages the major septa become short and the large axial region contains a moderately complex structure of generally thin septal lobes and lamellae. The number of major septa at a particular diameter is shown in Text-figure 34. Near the tip the major septa are almost completely dilated. Dilation decreases up- ward. Septal dilation in some specimens is greater on the cardinal side than on the counter side (PI. 11, figs. 3, 11). In early stages the cardinal septum is long and thicker than the other septa (Pl. 11, figs. 2, 3). In in- termediate stages it becomes thinner than the other septa and the fossula is narrow. In late stages the car- dinal septum becomes short, and a broad, prominent fossula develops (Pl. 11, figs. 4, 5). In early to inter- mediate stages the major septa on the cardinal side tend to impinge on the cardinal septum or fossula, and septa on the counter side tend to impinge on the long alar septa. The minor septa are poorly developed and confined to the narrow stereozone. Tabulae first appear when the axial region begins to develop. They are mostly complete and very closely to widely spaced. The tabulae are slightly convex up- ward within the septal and axial regions, but are con- cave upward at the junction of the two regions (Stumm, 1963, pl. 2, fig. 2). They are depressed in the 60 O 1S cardinal fossula. A few complementary plates (see B. Neuman, 1969, p. 6) are present. Microstructure.—Septal fibers are well developed, and the trabeculae are slightly inclined up toward the axis. Lamellae are rarely present in the stereozone. Discussion.—Foerste (1918) reported Streptelasma rusticum in the Ogontz Member and immediately be- neath in the Bay de Noc Member of the Stonington Formation in Delta County, Michigan. Stumm (1963) described and illustrated a single specimen from the Bay de Noc Member in the same area and assigned it to S. rusticum. These specimens are Grewingkia del- tensis nN. sp. G. deltensis is distinguished from other species of the genus by its broad, prominent cardinal fossula with short cardinal septum in late stages, and tabulae that are convex upward within the septal and axial regions but concave upward at the junction of the two regions. It resembles species of this genus from the continental interior of the Red River—Stony Mountain Province in being trochoid and moderately curved (see Elias, 1981). Grewingkia rustica (Billings, 1858a) Plate 11, figures 12-29 1858a. Petraia rustica Billings, pp. 168, 169. 1858b. Petraia rustica Billings. Billings, pp. 422, 423. 1901. Streptelasma rusticum (Billings). Lambe, pp. 110-112 [partim], pl. 7, figs. 2, 2a, 3. 1908. Streptelasma rusticum (Billings). Cumings, pp. 708, 709 [partim], non pl. 2, fig. 2, 2a, 2b. 1924. Streptelasma rusticum (Billings). Foerste, pp. 65, 66 [partim], non pl. 1, figs. la—c, 2a—c, pl. 2, fig. 6a—c. 17 sections from 10 corals 20 30 40 diameter, mm Text-figure 34.—Relation between number of major septa (n) and coral diameter in Grewingkia deltensis n. sp. ORDOVICIAN RUGOSE CORALS: ELIAS 71 1937. Streptelasma rusticum (Billings). Cox, pp. 11-13 [partim], non pl. 2, figs. 11, 12a—c, 13a—d. 1963. Streptelasma rusticum (Billings). Stumm, pp. 26, 27 [partim], pl. 2, figs. 8-10, non pl. 2, figs. 1-3. Lectotype (designated herein).—GSC 5822b, c; Snake Island, Lake St. John, Québec; J. Richardson collection, 1857 (Lambe, 1901, [?] pl. 7, fig. 3; Pl. 11, fig. 12). Paralectotype (designated herein).—GSC 5822, 5822a; Snake Island, Lake St. John, Québec; J. Rich- ardson collection, 1857 (Lambe, 1901, pl. 7, fig. 2, 2a). Other Specimens.— GSC 8527, 8527a, c, e, f, h, j-s (16 specimens), and UMMP 45351, 45352; Snake Island, Lake St. John, Québec; Foerste collection. UCGM 45592; Meaford beds, upper member of the Georgian Bay Formation; locality 19b, Manitoulin Is- land, Ontario; Elias collection. Occurrence.—Upper Ordovician (Richmondian): Richmond Group; Snake Island, Lake St. John, Queé- bec, Canada. Meaford beds, upper member of the Georgian Bay Formation; Manitoulin Island, Ontario, Canada. Diagnosis.—Grewingkia with complex axial struc- ture of numerous septal lobes and lamellae in late stage immediately below calice. Major septa completely di- lated in early stage and greatly dilated in later stages until immediately below calice, where dilation of septa 60 n4O x Manitoulin Is. e Lake St. John 19 20 O 10 diameter, and axial structure decreases. Major septa generally form counterclockwise whorl in early and intermediate stages. Description of Corals.—The largest specimen ex- amined (GSC 5822h, c) has a length of 65 mm but is incomplete at both ends. It has a diameter of 30 mm immediately below the calice where 54 major septa are present. The corals are ceratoid to trochoid in early stages, and become cylindrical in later stages. They are straight to slightly curved. Septal grooves and in- terseptal ridges are present on the epitheca. Depth of the calice is 40 percent of the coral length (GSC 58271, n). The sides of the calice are steep and the boss is slightly convex (GSC 5827a, Pl. 11, fig. 28s). Ontogeny and Internal Structures.—In early stages the major septa extend to or almost to the axis. A few greatly dilated septal lobes soon appear, followed by septal lamellae. A large, complex axial structure of numerous septal lobes and lamellae is developed in later stages in the less dilated zone immediately below the calice. The number of major septa at a particular diameter is shown in Text-figure 35. The major septa are com- pletely dilated in early stages and remain greatly di- lated in later stages until immediately below the calice, where dilation of the septa and axial structure de- creases. In early stages the cardinal septum is long and commonly is thicker than the other major septa. e e e e e ee e e OZ 4 © e e x x 2 sections from 1. coral(s) ” 10 ” 20 30 mm Text-figure 35.—Relation between number of major septa (n) and coral diameter in Grewingkia rustica (Billings, 1858a). Numbers indicate frequency of a point if greater than one. 2, BULLETIN 314 In intermediate and late stages it becomes thinner and a narrow fossula develops. In most specimens the major septa form a counterclockwise whorl in early to intermediate stages (Pl. 11, figs. 22, 23, 26, 27, 28s; see Laub, 1978). In later stages the minor septa are confined to or extend a short distance beyond the moderately broad stereozone. Tabulae, first appearing in intermediate stages, are mostly complete and moderately to widely spaced. They vary from slightly depressed axially (UMMP 45352, Stumm, 1963, pl. 2, fig. 10), to slightly convex upward (GSC 5822, 5822a, Lambe, 1901, pl. 7, fig. 2a), to highly convex upward (GSC 8527), Pl. 11, fig. 13). A few complementary plates (see B. Neuman, 1969, p. 6) are present. Microstructure.—Septal fibers are well developed, and trabeculae are slightly inclined up toward the axis. Lamellae are not present in the stereozone. Discussion.—Solitary corals from Snake Island, Lake St. John, Québec, were first listed as Strepto- plasma corniculum by Richardson (1858, p. 89). Bil- lings (1858a, 1858b) described Richardson’s specimens as a new species, Petraia rustica, but did not provide figures. Lambe (1901) examined the types and figured two corals that had been collected at Snake Island by Richardson in 1857. These were almost certainly Bil- lings’ syntypes, and are herein designated as the lec- totype and paralectotype. Only those portions of the descriptions and illustrations in Lambe (1901), Cum- ings (1908), Foerste (1924), Cox (1937), and Stumm (1963) dealing with specimens from Snake Island are synonymous with Grewingkia rustica (Billings, 1858a). Their other material and all references to this species not included in the synonymy belong to other species. G. canadensis (Billings, 1862), a widespread Rich- mond Group species, is similar to G. rustica in exter- nal form, and the two may be related. G. rustica is distinct in having major septa that generally form a counterclockwise whorl in early to intermediate stages, and are completely to greatly dilated until im- mediately below the calice in late stages, where dila- tion decreases and a complex axial structure develops. The cardinal and counter septa in G. canadensis com- monly are distinct, being longer than the other septa throughout ontogeny and having greatly dilated lobes in intermediate stages. The number of major septa at a particular diameter for G. rustica is at the low end of the range of values for G. canadensis (Text-figs. 33, 35). One solitary coral from the base of the Meaford beds on Manitoulin Island, Ontario, has a thin, relatively short cardinal septum and a counterclockwise whorl in its latest stage (UCGM 45592, PI. 11, fig. 27). The number of septa at a particular diameter is lower than that for specimens of G. canadensis from Manitoulin Island (Text-figs. 20, 35). Because of these features, it is assigned to G. rustica, although the long cardinal and counter septa in the intermediate stage (PI. 11, fig. 26) resemble G. canadensis. Except for this single specimen, G. rustica is known only from Lake St. John, Québec. Grewingkia penobscotensis n. sp. Plate 12, figures 1-6 Derivation of Name.—The specific name refers to Penobscot County, Maine, where the species occurs. Holotype.—USNM 311748; R. B. Neuman collec- tion (Pl. 12, figs. 3-5). Paratypes.—USNM 311749, 311750, 311751 (Pl. 12, figs. 1, 2), 311752-311756, 311757 (PI. 12, fig. 6); R. B. Neuman collection. Occurrence.—Upper Ordovician (Ashgill): About 520 m above base of unnamed formation; between Pond Pitch and Haskell Rock Pitch, East Branch, Pe- nobscot River, Penobscot County, Maine, U.S.A. Diagnosis.—Grewingkia with coarse axial structure that develops early in ontogeny and consists of a few moderately dilated septal lobes and lamellae. Major septa slightly dilated to non-dilated during ontogeny. Cardinal septum indistinct, cardinal fossula not de- veloped. Calicular boss prominent. Description of Corals.—The specimens are poorly preserved and incomplete. The largest coral examined (USNM 311748) has a diameter of 25 mm and 51 major septa in the calice. The corals are ceratoid to trochoid and slightly curved. The calicular boss is prominent (Pl. 12, figs. 1, 3). Ontogeny and Internal Structures.—A coarse axial structure of a few moderately dilated septal lobes and lamellae appears early in ontogeny. The number of major septa at a particular diameter is shown in Text- figure 36. The major septa are non-dilated to slightly dilated. The cardinal septum is indistinct and a fossula 50 ve 9 sections from 8 corals O 10 20 diameter, mm Text-figure 36.—Relation between number of major septa (n) and coral diameter in Grewingkia penobscotensis n. sp. ORDOVICIAN RUGOSE CORALS: ELIAS WS is not developed. The minor septa extend a short to moderate distance beyond the moderately broad stereozone. The tabulae are somewhat irregular, most- ly complete, and moderately convex upward (Pl. 12, fig. 1). Tabulae are concave upward at the periphery of the coral in only one specimen (USNM 311748, PI. 12, fig. 3). Complementary plates (see B. Neuman, 1969, p. 6) are present in some specimens. Microstructure.—The specimens are poorly pre- served, but some weakly developed septal fibers can be distinguished, and weak trabeculae are inclined up toward the axis. Discussion.—Grewingkia penobscotensis n. sp. is distinguished from other species of the genus by its non-dilated to slightly dilated septa, coarse axial struc- ture of a few septal lobes and lamellae, indistinct car- dinal septum, and lack of a fossula. Grewingkia pulchella (Billings, 1865) Plate 12, figures 7-21 1865. Petraia pulchella Billings, pp. 429, 430. 1865. Petraia selecta Billings, p. 429 [partim]. 1866. Petraia pulchella Billings. Billings, p. 33. 1866. Petraia selecta Billings. Billings, p. 7 [partim]. 1901. Streptelasma selectum (Billings). Lambe, p. 113 [partim], pl. 6, fig. 8, 8a. 1928. Streptelasma selectum (Billings). Twenhofel, p. 113 [partim). Lectotype (designated herein).—GSC 2243, 2243a; Ellis Bay Formation; Ellis Bay, Anticosti Island, Qué- bec; T. C. Weston collection, 1865 (Lambe, 1901, pl. 6, fig. 8, 8a). Other Specimens.— (All from Twenhofel collection, Anticosti Island, Québec, unless otherwise stated.) YPM 28723; Twenhofel’s zone 5, upper member of the Vauréal Formation; zone 8 of Twenhofel’s Vauréal River section. GSC 1989e; GSC 1989h; GSC 19897, 7; GSC 1989k; GSC 1989]; GSC 1989m; GSC 1989n; upper member, 27 to 30 m below top of Vauréal Formation; west end lighthouse; J. Richardson collection, 1856 (probably syntypes of Petraia selecta). YPM 28724, 28725; upper member (English Head facies) of the Vauréal Formation; West Bay. YPM 28726-28728; Ellis Bay Formation; Cape James Bay. YPM 28729, 28730; Ellis Bay Formation; west side of Prinsta Bay. YPM 28731-28733; Ellis Bay Formation; west side of Ellis Bay. YPM 28734; Ellis Bay Formation; cliff 1.2 km east of Junction Cliff. YPM 28735; Ellis Bay Formation; Prinsta Bay. YPM 28736; Ellis Bay Formation; Twenhofel’s zone 13 at Cape James. YPM 28737; Ellis Bay Formation; zone 15 of Twen- hofel’s Vauréal River section. YPM 28738; Ellis Bay Formation; zone 22 of Twen- hofel’s Vauréal River section. YPM 28739; Ellis Bay Formation; Twenhofel’s zone D, west side of Ellis Bay. YPM 28740; basal unit, Ellis Bay Formation; zone 10 of Twenhofel’s Vauréal River section. YPM 28721; upper Ellis Bay Formation; cliff be- tween Bear Cape and Cape Eagle. YPM 28741-28745; Twenhofel’s zone 1, Ellis Bay Formation; Junction Cliff. YPM 28746; Twenhofel’s zone 1, Ellis Bay For- mation; west side of Ellis Bay. YPM 28747; Twenhofel’s zone 2, Ellis Bay For- mation; Junction Cliff. YPM 28748-28750; Twenhofel’s zone 2, Ellis Bay Formation; Junction Cliff. YPM 28751; Twenhofel’s zone 2, Ellis Bay For- mation; west side of Ellis Bay. YPM 28752; Twenhofel’s zone 6, Ellis Bay For- mation; east of Junction Cliff. YPM 28753; Twenhofel’s zone 7 (Hormotoma gi- gantea zone), Ellis Bay Formation; Ellis Bay. YPM 28754, 28755; Twenhofel’s zone 8, Ellis Bay Formation; west side of Ellis Bay. YPM 28756; Twenhofel’s zone 9, Ellis Bay For- mation; reef at Ellis Bay. YPM 28757; Twenhofel’s zone 9, bioherm at base of Bolton’s member 6, Ellis Bay Formation; Raspber- ry Point. YPM 28758-28760; Twenhofel’s zone 9, Ellis Bay Formation; Ellis Bay. YPM 28761; Twenhofel’s zone 10, Ellis Bay For- mation; west side of Ellis Bay. YPM 28722; Bolton’s member 6, Ellis Bay Forma- tion; Cape Eagle. USNM 311717-311735; unnamed unit; USGS local- ity 4112-CO, 9 km east of Ashland, Maine; R. B. Neu- man collection. Occurrence.—Upper Ordovician: Upper member (lower to middle Ashgill) of the Vauréal Formation, and Ellis Bay Formation (Ashgill; Gamachian); Anti- costi Island, Québec, Canada. Unnamed unit (Ash- gill); 9 km east of Ashland, Maine, U.S.A. Diagnosis.—Grewingkia with relatively small axial structure of completely dilated septal lobes in inter- mediate stage, and a few moderately to greatly dilated septal lobes and lamellae in late stage. Major septa completely dilated in early stage and slightly to mod- erately dilated in later stages. 74 BULLETIN 314 Description of Corals.—The length of corals is shown in Text-figure 23 (see discussion under **Anti- costi Island, Québec’’). The longest specimen exam- ined (YPM 28755) has a length of 30 mm and is 13 mm in diameter immediately below the calice where 32 major septa are present. The corals are ceratoid to trochoid and are commonly slightly curved. A tiny area of attachment at the tip on the cardinal side is rarely present (YPM 28744, 28745). The epitheca has prominent septal grooves and interseptal ridges. Depth of the calice is 40 percent of the coral length (YPM 28734, Pl. 12, fig. 19). The calicular boss is moderately to highly convex. Ontogeny and Internal Structures.—In early stages the major septa extend to the axis. In intermediate stages the axial structure is generally dense, consisting of completely dilated septal lobes. In late stages a few moderately to greatly dilated septal lobes and lamellae comprise the moderately small axial structure. The number of major septa at a particular diameter is shown in Text-figure 37. In early stages the septa n Ba o 2. + Anticosti Is, Quebec 41 sections from 24 corals O Ashland, Maine 6 e « 6 O 10 20 diameter, mm Text-figure 37.—Relation between number of major septa (n) and coral diameter in Grewingkia pulchella (Billings, 1865). Numbers indicate frequency of a point if greater than one. are completely dilated. They are generally greatly but less commonly completely dilated in intermediate stages. In late stages they are slightly to moderately dilated. The cardinal septum commonly is indistinct and the cardinal fossula is narrow. Minor septa extend a short distance beyond the narrow to moderately broad stereozone in late stages. Tabulae are sparse in late stages, and are incomplete and irregular in devel- opment. Microstructure.—Septal fibers are well developed and trabeculae are slightly inclined up toward the axis. Lamellae are present in the stereozone in incompletely dilated stages. Discussion.—Billings (1865) based his original de- scription of Petraia pulchella on two specimens. One of these was figured by Lambe (1901, pl. 6, fig. 8, 8a) and is herein designated as the lectotype of Grewing- kia pulchella (Billings, 1865). The other specimen is unknown. Several of the probable syntypes of Petraia selecta Billings (1865) (=Helicelasma selectum) are G. pulchella. Billings’ P. pulchella was considered a syn- onym of P. selecta by Lambe (1901) and Twenhofel (1928), but two species are definitely involved. G. pulchella is distinguished from other species of the genus by its relatively small axial structure, which consists of completely dilated septal lobes in inter- mediate stages, and a few moderately to greatly dilated septal lobes and lamellae in late stages. Helicelasma sp. A from the Upper Ordovician Centrum Formation of northeastern Greenland is similar, but has more septa at a particular diameter (see Scrutton, 1975, pp. 16, 17, pl. 2, figs. 4, 5). Grewingkia sp. Plate 12, figures 22—25 Specimens.—YPM 28762, USNM 311638. Occurrence.—Upper Ordovician (lower to middle Ashgill): Stenopareia faunal zone, White Head For- mation; Grande Coupe, 2.4 km northwest of Perce, Québec, Canada. Description.—The corals attain moderate size. In early stages the major septa extend to the axis. In intermediate stages the major septa are withdrawn from the axis and a few septal lobes and short lamellae form a small, very weakly defined axial structure. In late stages the relatively small axial structure consists of moderately dilated septal lobes and lamellae. The major septa are non-dilated to slightly dilated. The car- dinal septum and fossula are indistinct. The minor septa are short and commonly are confined to the ster- eozone, which becomes broad in late stages. Tabulae are present. Microstructure.—The septa appear to be slightly fi- brous, and lamellae are present in the stereozone. Discussion.—These two specimens are distinct in having the major septa withdrawn from the axis in intermediate stages, where a few septal lobes and la- mellae form a small, very weakly defined axial struc- ture. Assignment to a species (probably new) must await the discovery of more specimens from which additional information can be obtained. Genus LOBOCORALLIUM Nelson, 1963 1963. Lobocorallium Nelson, pp. 34, 35 [partim). 1981. Lobocorallium Nelson. Nelson, p. 49 [partim]. Type Species (by original designation).—Streptelas- ma rusticum var. trilobatum Whiteaves (1895, p. 113). Stony Mountain Formation (Upper Ordovician); Stony Mountain, Manitoba, Canada. ORDOVICIAN RUGOSE CORALS: ELIAS 75 Diagnosis.—Coral solitary, trochoid, and attains very large size. Cross-section trilobate. Calice of mod- erate depth with slightly convex calicular boss. Cardinal septum on convex side of coral. Major sep- ta completely dilated until immediately below calice. Minor septa poorly developed. Axial structure in latest stage comprises greatly to completely dilated septal lobes or lobes and lamellae. Tabellae in septal region. Tabulae in axial region mostly complete and slightly concave to convex upward. Species and Occurrences.—Lobocorallium is known from the Upper Ordovician of North America. The following species are included in the genus: 1895. Streptelasma rusticum var. trilobatum (=L. trilobatum tri- lobatum) Whiteaves, p. 113. Upper Ordovician (lower to middle Ashgill): Gunn and Penitentiary Members of the Stony Mountain Formation; Stony Mountain, Manitoba, Canada. 1928. Zaphrentis vaurealensis (=L. trilobatum vaurealense) Twen- hofel, pp. 116, 117, pl. 3, fig. 1. Upper Ordovician (lower to mid- dle Ashgill): Upper member of the Vaureal Formation; Anticosti Island, Québec, Canada. White Head Formation; Perce, Quebec, Canada. Discussion.—Lobocorallium was proposed by Nel- son (1963) to include the trilobate corals Streptelasma rusticum Var. trilobatum, S. goniophylloides Teichert (1937), and L. trilobatum var. major Nelson (1963). The latter two species have ontogenies and axial struc- tures characteristic of Grewingkia Dybowski (1873), and have been assigned to G. haysii (Meek, 1865) by Elias (1981, p. 18). Trilobation appears within several species of Grewingkia and Deiracorallium, and its sig- nificance as a generic trait is uncertain, as was dis- cussed under the latter genus. Lobocorallium is pres- ently considered distinct in having completely dilated septa until immediately below the calice, where an axial structure of greatly to completely dilated septal lobes, or lobes and lamellae, is developed in late stages. G. haysii and L. trilobatum vaurealense are intermediate forms linking Grewingkia and Lobocor- allium, as was discussed under the former genus. Lobocorallium trilobatum vaurealense (Twenhofel, 1928) Plate 13, figures 1-7 1928. Zaphrentis vaurealensis Twenhofel, pp. 116, 117, pl. 3, fig. 1. 1980. Lobocorallium vaurealensis (Twenhofel). Bolton, pl. 2.4, figs. 4, 8, pl. 2.7, figs. 2, 3. Holotype (by original designation).—YPM 20482; Twenhofel’s zone 5, upper member of the Vauréal Formation; zone 7 of Twenhofel’s Vauréal River sec- tion, Anticosti Island, Québec; Twenhofel collection (Twenhofel, 1928, pl. 3, fig. 1; Pl. 13, figs. 1s, 2). Other Specimens.— GSC 66590, 66591; upper member, about 50 m be- low top of Vauréal Formation; GSC locality 36157, main highway section, cut approximately 10.4 km from Port Menier, Anticosti Island, Québec; Bolton collection. GSC 53556; upper member of the Vaureal Forma- tion; first creek before shore, Martin Bay road, Anti- costi Island, Québec. USNM 311635, GSC 53545; Stenopareia faunal zone, White Head Formation; Grande Coupe, 2.4 km northwest of Percé, Québec. GSC 53546, 53547; unit 4 of White Head Formation; Flynn road, 1 km southwest of Perce, Québec. Occurrence.—Upper Ordovician (lower to middle Ashgill): Upper member of the Vauréal Formation; Anticosti Island, Québec, Canada. White Head For- mation; Percé, Québec, Canada. Diagnosis. —Compressed Lobocorallium with rela- tively large, complex axial structure of septal lobes and lamellae in late stage. Axial structure and septa completely dilated until immediately below calice, where dilation is great. Description of Corals.—The largest specimen ex- amined has a length of 150 mm (YPM 20482, Pl. 13, fig. 1s). Another specimen (GSC 66591) has 71 major septa at a cross-sectional area of 1025 mm?. The corals are trochoid and slightly to moderately curved. They are compressed throughout ontogeny, and the maxi- mum cross-sectional length-width ratio is 1.3 (USNM 311635). In cross-section the corals are trilobate throughout ontogeny (PI. 13, fig. 1s). Trilobation is most pronounced several cm above the tip, and de- creases upward. Depth of the calice is 20 percent of the coral length (YPM 20482, Pl. 13, fig. 2). The calic- ular boss is slightly convex. Ontogeny and Internal Structures.—In early stages the major septa extend to the axis. A few completely dilated septal lobes and lamellae appear in intermedi- ate stages. In the latest stages the relatively large, complex axial structure consists of greatly dilated sep- tal lobes and lamellae. The number of major septa at a particular cross- sectional area is shown in Text-figure 38. The septa and axial structure are completely dilated until im- mediately below the calice (Pl. 13, figs. 5, 6). The car- dinal septum is long, and a cardinal fossula generally is not developed. In early to intermediate stages the major septa on the cardinal side tend to impinge on the cardinal septum, and septa on the counter side tend to impinge on the long alar septa. Minor septa are poorly developed and often indistinct because of the completely dilated major septa. 76 BULLETIN 314 Tabellae that are convex upward are present in the septal region. They are inclined up toward the axis in early stages and become less steeply inclined with in- creased height in the coral. They are oriented hori- zontally in late stages. Tabulae in the axial region are mostly complete, moderately spaced, often dilated, and approximately horizontal (Pl. 13, fig. 2). Microstructure.—Septal fibers are well developed, and lamellae are present in the stereozone. Discussion.—The following specimens of Lobocor- allium trilobatum trilobatum (Whiteaves, 1895) from the Gunn and Penitentiary Members of the Stony Mountain Formation at Stony Mountain, southern Manitoba, have been examined (Elias, 1981, p. 12): GSC 6825 (collected by T. C. Weston in 1884; this specimen is probably a syntype), 60757, 60763-60771. L. trilobatum vaurealense (Twenhofel, 1928) differs in having less pronounced trilobation, a larger axial structure that is slightly less dilated in the latest stages and consists of septal lamellae in addition to lobes, and in possessing fewer major septa at a particular cross-sectional area (Text-fig. 38). If L. trilobatum vaurealense was the immediate ancestor of L. trilo- batum trilobatum, it can be added to the possible evo- 100 50 lutionary sequence Grewingkia robusta (Whiteaves, 1896) — G. haysii (Meek, 1865) = L. trilobatum vau- realense — L. trilobatum trilobatum (see Elias, 1981, p. 6). L. trilobatum vaurealense could also have been a contemporary geographic variant of L. trilobatum trilobatum. It is closer to L. trilobatum trilobatum than to G. haysii, which is generally not as markedly trilobate and has less pronounced septal dilation and a better developed axial structure (see Elias, 1981, pp. 17, 18, pl. 5, figs. 1-15, pl. 6, figs. 1-12). These corals are therefore included in Lobocorallium, and are not considered sufficiently different from L. trilobatum trilobatum to constitute a separate species. Genus KENOPHYLLUM Dybowski, 1873 1873. Kenophyllum Dybowski, p. 358. 1958. Kenophyllum Dybowski. Kaljo, pp. 22, 23. 1961. Kenophyllum Dybowski. Kaljo, pp. 59, 60. 1977. Kenophyllum Dybowski. McLean, pp. 14, 15. 1977. Kenophyllum Dybowski. B. Neuman, pp. 74, 75. Type Species (by monotypy).—Kenophyllum sub- cylindricum Dybowski (1873, p. 358). Vormsi Horizon (Upper Ordovician); Estonia. Discussion.—Kenophyllum is presently considered e Lobocorallium trilobatum trilobatum x L. trilobatum vaurealense : Grewingkia haysii O 500 1bOO 1000 cross-sectional area, mm2 Text-figure 38.—Relation between number of major septa (n) and coral cross-sectional area in Lobocorallium trilobatum trilobatum (Whit- eaves, 1895) from the Stony Mountain Formation, Stony Mountain, Manitoba; Lobocorallium trilobatum vaurealense (Twenhofel, 1928) from the Vauréal Formation, Anticosti Island, Québec, and the Stenopareia faunal zone of the White Head Formation, Perce, Québec; Grewingkia haysii (Meek, 1865) from Manitoba, Northwest Territories, and northwestern Greenland (see Elias, 1981, fig. 11b). ORDOVICIAN RUGOSE CORALS: ELIAS 77 distinct in having greatly to completely dilated septa throughout ontogeny, a dense axial structure of com- pletely dilated septal lobes and lamellae, a cardinal fossula that commonly is prominent, and rare or ab- sent tabulae. In the type species, the cardinal septum is almost always on the concave side of the coral, but also occurs on the convex side. This genus is known from the Upper Ordovician of Estonia and from ques- tionable occurrences in the Ashgill (Upper Ordovi- cian) of Maine and upper Llandovery (Lower Silurian) of western North Greenland. Other authors have discussed the close relationship of Kenophyllum with Leolasma Kaljo (1956) (Scrut- ton, 1971, p. 211; B. Neuman, 1975, pp. 338-341; McLean, 1977, p. 15), Grewingkia Dybowski (1873) (B. Neuman, 1975, pp. 339, 340; 1977, p. 75), Cras- silasma Ivanovskiy (1962) (McLean, 1977, p. 15), and Pycnactis Ryder (1926) (Kaljo, 1961, p. 60; see B. Neuman, 1977, p. 75). Kenophyllum? sp. Plate 13, figures 8, 9 Specimens.—USNM 311758, 311759; R. B. Neuman collection. Occurrence.—Upper Ordovician (Ashgill): About 61 m above base of unnamed formation; between Pond Pitch and Haskell Rock Pitch, East Branch, Penobscot River, Penobscot County, Maine, U.S.A. Description of Corals.—The largest specimen ex- amined (USNM 311758) has a diameter of 18 mm and 37 major septa at an unknown distance below the cal- ice. It is not known whether the cardinal septum oc- curs on the concave or convex side of the coral. Ontogeny and Internal Structures.—In early stages the major septa extend to the axis. In later stages, a dense, solid axial structure of a few greatly dilated septal lobes and lamellae enclosed in stereoplasmatic deposits is present. In early stages, the septa are com- pletely dilated. The major septa are greatly dilated in later stages, where the cardinal septum appears to be shorter than the others, creating a pronounced fossula. Minor septa are confined to the stereozone. Microstructure.—The microstructure is unknown because the specimens are poorly preserved. Discussion.—These two incomplete specimens ap- pear to have the ontogeny and axial structure char- acteristic of Kenophyllum, but assignment to the ge- nus remains questionable until the ontogeny is more completely known. The nature of the cardinal septum and fossula in late ontogenetic stages resembles K. subcylindricum Dybowski (1873) from the upper Ca- radoc—lower Ashgill (Upper Ordovician) of Estonia (Kaljo, 1961, pl. 4, fig. 6). Genus BODOPHYLLUM B. Neuman, 1969 1969. Bodophyllum B. Neuman, pp. 54-56. Type Species (by original designation).—Bodophyl- lum osmundense B. Neuman (1969, pp. 56-59). Boda Limestone (Upper Ordovician); Osmundsberg, Siljan district, Sweden. Discussion.—Bodophyllum, as presently under- stood, is characterized by a dense to solid axial struc- ture composed of septal lobes and very few lamellae, with a commonly prominent median lamella joining the cardinal and counter septa and forming a calicular boss (see B. Neuman, 1969, fig. 45). B. Neuman (1969, p. 56) reported this Upper Ordovician genus from Sweden and Norway, and noted probable occurrences in Scotland and North America. In North America it is present in the upper Upper Ordovician of the east- ern Great Basin (Budge, 1977), in the Ashgill of An- ticosti Island, Québec, and Maine, questionably in the lower to middle Ashgill at Percé, Québec, and in the ?Gamachian of Missouri. Uncertainty concerning the relationship of Bodo- phyllum with other genera is indicated by the following points: 1. Bodophyllum is very similar to Bighornia Duncan (1957), but has the cardinal septum on the convex rather than concave side of the coral. However, some specimens of Bighornia orvikui Kaljo (1960) have a convex cardinal side, suggesting that the position of the cardinal septum may not be generically significant. Spec- imens of Bighornia are generally subcalceoloid in form, as is Bodophyllum duncanae (Spjeldnaes, 1961). . The significance of a dilated median septal lamella in the axial structure is uncertain. Grewingkia bilateralis B. Neuman (1969), G. lamellosa Elias (1981), and some specimens of Streptelasma cyrtum B. Neuman (1969) also have a median lamella. In late ontogenetic stages of Bodophyllum shorti n. sp., the axial struc- ture resembles that of Grewingkia because the median lamella is slightly dilated and irregular, and other septal lobes and la- mellae are present. tN McLean (1974, p. 43) suggested that Bodophyllum, Bighornia, Dalmanophyllum Lang and Smith (1939), and Ditoecholasma Simpson (1900) may be synony- mous. Bodophyllum shorti n. sp. Plate 13, figures 10-14 Derivation of Name.—The species is named for the former owner of the farm on which this coral was found at the type section of the Leemon Formation. Holotype and Only Specimen.—UCGM 45613; Elias collection (Pl. 13, figs. 10-14). Occurrence.—Upper Ordovician (?Gamachian): Leemon Formation; locality 20a, Cape Girardeau County, Missouri, U.S.A. 78 BULLETIN 314 Diagnosis.—Bodophyllum with solid axial structure in early stage and a prominent dilated median septal lamella in intermediate stage. In late stage a few septal lobes and lamellae are present in axial structure, and median lamella is slightly dilated, irregular, and not connected to cardinal or counter septa. Minor septa long, extending well beyond stereozone. Description of Coral.—The coral is about 15 mm long and has a diameter of 8 mm a short distance below the calice where 34 major septa are present. It is straight. The base of attachment is on the cardinal side, and the specimen was attached to a bryozoan. Depth of the calice is about 40 percent of the coral length. Ontogeny and Internal Structures.—The axial structure is solid in early stages. In intermediate stages a prominent dilated median septal lamella is connected to the long cardinal and counter septa and a few dilated septal lobes and rare septal lamellae are present. In late stages the elements of the axial structure are slightly dilated. The median lamella is irregular and discontinuous, and is not connected to the cardinal or counter septa. A few other septal lamellae and septal lobes are present. The major septa are slightly dilated in early stages, and non-dilated in later stages. A car- dinal fossula is not developed. The minor septa are long, extending well beyond the narrow stereozone. Tabulae are present. Microstructure.—Septal fibers are present. Lamel- lae apparently are not developed in the stereozone. Discussion.—Bodophyllum shorti n. sp. has a solid axial structure in early stages, and a prominent dilated median septal lamella plus a few septal lobes and rare lamellae in intermediate stages. The species is as- signed to Bodophyllum because of these characteristic features. However, in other species of the genus the dense to solid axial structure is present in late stages as well (see B. Neuman, 1969). B. shorti is distinct in having a slightly dilated axial structure in late stages, and long minor septa. Streptelasma leemonense na. sp., from the same locality, has very long minor septa but lacks an axial structure. Bodophyllum neumani n. sp. Plate 14, figures 1-6 Derivation of Name.—The species is named for Robert B. Neuman, U.S. Geological Survey, who col- lected the specimens. Holotype.—USNM 311760; R. B. Neuman collec- tion (Pl. 14, figs. 3, 4). Paratypes.—USNM 311761 (PI. 14, fig. 1), 311762 (Pl. 14, figs. 5, 6), 311763, 311764 (PI. 14, fig. 2), 311765, 311766; R. B. Neuman collection. Occurrence.—Upper Ordovician (Ashgill): About 520 m above base of unnamed formation; between Pond Pitch and Haskell Rock Pitch, East Branch, Pe- nobscot River, Penobscot County, Maine, U.S.A. Diagnosis.—Bodophyllum with prominent, elon- gate, dilated median septal lamella and a few septal lobes forming axial structure in all known ontogenetic stages. Description of Corals.—The largest specimen ex- amined (USNM 311762) has a diameter of 13 mm and 30 major septa at an unknown distance below the ca- lice. The corals are ceratoid and straight. Septal grooves and interseptal ridges are present on the epi- theca. Ontogeny and Internal Structures.—The axial structure in all known ontogenetic stages consists of a prominent, elongate, dilated median septal lamella joining the cardinal and counter septa, and a few septal lobes originating from other major septa. The number of major septa at a particular diameter is shown in Text-figure 39. The major septa are non-dilated. Minor 30 e e . 7 sections from n 7 corals diameter, mm Text-figure 39.—Relation between number of major septa (n) and coral diameter in Bodophyllum neumani 0. sp. septa extend a short distance beyond the narrow ste- reozone. The tabulae are mostly complete and mod- erately convex upward. Complementary plates (see B. Neuman, 1969, p. 6) are present in some specimens. Microstructure.—The microstructure is unknown because of poor preservation. Discussion.—Bodophyllum neumani n. sp. is distin- guished from other species of the genus (see B. Neu- man, 1969) by its more elongate and prominent median septal lamella. B. shorti n. sp., from the ?Gamachian (Upper Ordovician) of Missouri, differs in having long- er minor septa and a median lamella that is slightly dilated, irregular, and not connected to the cardinal or counter septa in late stages. Bodophyllum? sp. Plate 14, figures 7-9 Specimen.—YPM 28763. Occurrence.—Upper Ordovician (lower to middle Ashgill): Stenopareia faunal zone, White Head For- ORDOVICIAN RUGOSE CORALS: ELIAS 79 mation; Grande Coupe, 2.4 km northwest of Perce, Québec, Canada. Description.—The small coral has an area on the cardinal side where it was attached to a brachiopod. In early stages a few septal lobes are present. In in- termediate and late stages a moderately dilated median septal lamella joins the cardinal and counter septa, and a few septal lobes originate from other major septa. In the late stage, 25 major septa are present. The major septa are non-dilated. Minor septa are confined to the moderately broad stereozone. Tabulae are present. Microstructure.—Septal fibers are not distinguish- able. Lamellae are developed in the stereozone. Discussion.—This specimen resembles Bodophyl- lum in having a median septal lamella connecting the cardinal and counter septa, but the assignment is ques- tionable because the axial structure is less dilated than is typical of the genus. A new species is not erected because only a single incomplete specimen is known. Bodophyllum englishheadense n. sp. Plate 14, figures 10-16 Derivation of Name.—The specific name refers to English Head, Anticosti Island, Québec, where the species has been collected. Holotype.—YPM 28764; English Bay; Twenhofel collection (Pl. 14, figs. 10-13). Paratypes.—YPM 28765, 28766 (Pl. 14, figs. 14-16); English Head; Twenhofel collection. YPM 28767, 28768; White Cliff; Twenhofel collection. Occurrence.—Upper Ordovician (lower to middle Ashgill): Upper member (English Head facies) of the Vauréal Formation; Anticosti Island, Québec, Cana- da. Diagnosis.—Bodophyllum with dense axial struc- ture throughout ontogeny, consisting of dilated median septal lamella plus septal lobes in intermediate and late stages. Stereozone becomes very broad in late stage, attaining width of up to half the coral radius. Description of Corals.—The largest complete spec- imen examined (YPM 28768) is 20 mm long and has a diameter of 14 mm immediately below the calice where 43 major septa are present. The corals are cer- atoid and some become cylindrical in late stages (YPM 28764, 28765). They are straight to slightly curved. The base of attachment is centered on the cardinal side. In One specimen (YPM 28766), the two corals that are attached to a bryozoan grew into lateral contact (PI. 14, figs. 14, 15). The epitheca has septal grooves and interseptal ridges, and coarse rugae are present on some specimens (YPM 28765, 28767). Depth of the calice is 40 percent of the coral length (YPM 28768). A calicular boss does not appear to be developed (YPM 28765). Ontogeny and Internal Structures.—In early stages the major septa extend to the axis where they are di- lated, forming a dense axial region. In intermediate and late stages a dilated median lamella connecting the long cardinal and counter septa is the dominant ele- ment in the axial structure. It is surrounded by the dilated axial ends and septal lobes of other major sep- ta, forming a dense axial region. The number of major septa at a particular diameter is shown in Text-figure 40. The major septa are slightly 50 O 10 20 diameter, mm Text-figure 40.—Relation between number of major septa (n) and coral diameter in Bodophyllum englishheadense n. sp. dilated to non-dilated. A distinct fossula is not devel- oped. The minor septa are almost always confined to the stereozone, which is moderately broad in early stages and becomes very broad in late stages when it attains a width of up to half the coral radius (Pl. 14, fig. 13). The tabulae appear in early stages and are mostly complete, slightly convex upward, and mod- erately spaced (PI. 14, fig. 10). Complementary plates (see B. Neuman, 1969, p. 6) are present. Microstructure.—The septal fibers are well devel- oped, and the trabeculae are inclined slightly up to- ward the axis. The stereozone is composed of lamel- lae. Discussion.—Bodophyllum englishheadense n. sp. is distinct in having a very broad stereozone, far broader than that in other species of the genus (see B. Neuman, 1969). Genus BIGHORNIA Duncan, 1957 1957. Bighornia Duncan, pp. 608-611. 1963. Bighornia Duncan. Nelson, pp. 39, 40. 1977. Bighornia Duncan. B. Neuman, p. 75. 1981. Bighornia Duncan. Elias, pp. 24, 25. Type Species (by original designation).—Bighornia parva Duncan (1957, pp. 611-614). Bighorn Dolomite 80 BULLETIN 314 (Upper Ordovician); Johnson County, Wyoming, WESPAE Discussion.—As presently understood, Bighornia includes solitary corals having a concave cardinal side, major septa that are generally completely dilated in early ontogenetic stages and may be greatly dilated even in later stages, and an axial structure with a prominent, greatly dilated median lamella. The rela- tionship of Bighornia and Densigrewingkia B. Neu- man (1969) is uncertain. The latter genus also has a concave cardinal side and a greatly dilated median septal lamella in the axial region (see B. Neuman, 1969, fig. 42). The axial structure in the latest stage of an unusually long specimen of B. cf. B. patella (A. E. Wilson, 1926) resembles Grewingkia, as does Densi- grewingkia (see Elias, 1981, pl. 10, fig. 13). The rela- tionship of Bighornia and Bodophyllum B. Neuman (1969) was discussed under the latter genus. B. Neu- man (1977, p. 75) commented on the similarity of Big- hornia, Bodophyllum, and Dalmanophyllum Lang and Smith (1939). Bighornia cf. B. patella (A. E. Wilson, 1926) Plate 14, figures 17-24; Plate 15, figures 1-11 1926. [cf.] Streptelasma patellum A. E. Wilson, p. 13, pl. 2, fig. 1. 1928. [?] Streptelasma aff. breve Ulrich in Winchell and Schuchert. Troedsson, p. 109, pl. 26, figs. 6, 7. 1929. Lindstrémia solearis Ladd, pp. 397-399, pl. 4, figs. 6-12. 1943. Holophragma anticonvexa Okulitch, pp. 68, 69, pl. 1, figs. il, 12 1956. **Holophragma”™’ sp. Duncan, pl. 22, fig. la—-c. 1957. ‘‘Holophragma”’ sp. R. J. Ross, pl. 37, figs. 3, 5-7. 1957. Bighornia parva Duncan, pp. 611-614, pl. 70, figs. 1-18. 1959b. Bighornia patella (A. E. Wilson). Nelson, pl. 4, fig. la—d. 1963. Bighornia patella (A. E. Wilson). Nelson, pp. 40, 41, pl. 11, figs. la—c, 2, 3a—d. 1963. Bighornia solearis (Ladd). Nelson, p. 41, pl. 11, fig. 4a—d. 1975. Bighornia sp. Norford and Macqueen, pl. 9, figs. 9, 10. 1981. Bighornia cf. B. patella (A. E. Wilson). Elias, pp. 25, 26, pl. 10, figs. 1-21. Specimens from Iowa.—SUI 2-051 (holotype of Lindstrémia solearis); Thomas collection (Pl. 14, figs. 21s—24). SUI 2-052 (paratype of L. solearis); Ivson collection (Pl. 14, fig. 20s). USNM 71926 (paratype of L. solearis); Tysor collection (Pl. 14, figs. 17s—19). Occurrence.—Upper Ordovician (Richmondian): Fort Atkinson Formation, Maquoketa Group; NW14, sec. 15, T96N, R8W, 1.2 km southwest of Ossian, Winneshiek County, Iowa, U.S.A. Description of Corals.—The largest specimen ex- amined (USNM 71926) has a length of 23 mm. The greatest observed number of major septa is 49 in the calice at a height of 19 mm (SUI 2-051). The cardinal side is concave. The corals are trochoid and slightly curved. They are depressed throughout their length, especially in early stages. In intermediate stages the cross-sectional length-width ratio is 1.4 (SUI 2-052). In late stages the ratio is 1.2 (USNM 71926, SUI 2-051). Two specimens (SUI 2-051, USNM 71926) have a spoon-shaped depression on the cardinal side near the tip (Pl. 14, figs. 19, 23). One of these (SUI 2- 051) also has a depression on the counter side in early stages (Pl. 14, fig. 24). One small specimen (SUI 2-052) is triangulate in cross-section, but in late stages the corals become oval (SUI 2-051, USNM 71926). Depth of the calice is 30 percent of the coral length (SUI 2-051). The calicular boss is moderately convex and a prominent columella that is elongate in the car- dinal-counter plane is present (PI. 14, figs. 17s, 20s, 21s). Internal Structures.—In intermediate and late stages the axial structure consists of a conspicuous, greatly dilated median lobe that is an extension of the counter septum, and a few other septal lobes and rare lamellae. The number of major septa at a particular height is shown in Text-figure 41 (b, b’). The major septa are moderately dilated in the calice, where the cardinal septum is short and the cardinal fossula is narrow. Minor septa are confined to or extend a very short distance beyond the stereozone. Microstructure.—The microstructure is not pre- served in these silicified specimens. Specimens from Anticosti Island.—(All from Twen- hofel collection, Anticosti Island, Québec): YPM 28769 (Pl. 15, figs. 1-6), 28770 (Pl. 15, figs. 7-11); low- er member (zone 4 of Twenhofel’s English Head For- mation) of the Vauréal Formation; Girard Harbour. YPM 28771. Occurrence.—Upper Ordovician (?Caradoc): Low- er member of the Vauréal Formation; Anticosti Island, Québec, Canada. Description of Corals.—The largest specimen ex- amined (YPM 28769) has a length of 28 mm. The max- imum observed number of major septa is 42 at a height of about 12 mm immediately below the calice (YPM 28770). The cardinal septum is on the concave side of the coral. The corals are trochoid and slightly curved. They are depressed throughout their length, especially in early stages. The maximum cross-sectional length- width ratio varies from 1.5 at a height of 7 mm (YPM 28769) to 2.7 at a height of about 3 mm (YPM 28770). The corals become triangulate during ontogeny. All specimens have a concave spoon-shaped area of at- tachment on the cardinal side near the tip (PI. 15, fig. 7). Growth lines and weakly developed septal grooves and interseptal ridges are preserved on the epitheca. Depth of the calice is 20 (YPM 28769, Pl. 15, fig. 6) to ORDOVICIAN RUGOSE CORALS: ELIAS 81 30 percent of the coral length (YPM 28770). The ca- licular boss is moderately convex. Ontogeny and Internal Structures.—Up to a height of several mm the major septa extend to the axis. Above this the axial structure consists of a conspicu- ous, greatly dilated median lobe that is an extension of the counter septum, and a few other septal lobes. The number of major septa at a particular height is shown in Text-figure 41 (f, f’). The major septa are completely dilated in early stages and moderately di- lated immediately below the calice. Dilation is greatest on the cardinal side. The cardinal septum becomes short in the calice. The cardinal fossula is narrow in 40 20 6 5 10 moderately dilated stages. Minor septa are confined to the moderately broad stereozone. A few thin, irregu- lar, incomplete tabulae are present in one specimen (YPM 28769, Pl. 15, fig. 6). Microstructure.—The septal fibers are well devel- oped, and weak trabeculae are present. Lamellae can- not be distinguished in the stereozone. Discussion.—Corals of Bighornia from Iowa and Anticosti Island, Québec, cannot be distinguished from the forms listed in synonymy and discussed in detail by Elias (1981, pp. 25, 26). They are referred to as B. cf. B. patella (A. E. Wilson, 1926) until the type specimen and topotype material of B. patella, from eb s ‘ ed eb eb 1 20 25 height, mm Text-figure 41.—Relation between number of major septa (n) and coral height in Bighornia patella (A. E. Wilson, 1926) and Bighornia cf. B. patella. Bighornia patella: a. GSC 6732, Beaverfoot Formation, southeastern British Columbia. Bighornia cf. B. patella: a’. GSC 10872 [B. patella], member No. 1, Caution Creek Formation, northern Manitoba. a’, a’’’. GSC 10873, 10874 [B. patella], member No. 1, Chasm Creek Formation, northern Manitoba. b, b’. SUI 2-051, USNM 71926 [Lindstrémia solearis|, Fort Atkinson Formation, Iowa. b’. GSC 10870 [B. solearis|, member No. 1, Chasm Creek Formation, northern Manitoba. ¢, ¢’. Holophragma anticonvexa of Okulitch (1943) and Nelson (1963), respectively, Gunn Member, Stony Mountain Formation, southern Manitoba. d, d’. USNM 127574, 124801 [B. parva], upper Bighorn Dolomite, Wyoming. e-e'’’. GSC 60752-60755, Selkirk Member, Red River Formation, southern Manitoba. f. YPM 28769, lower member, Vauréal Formation, Anticosti Island, Quebec. f’. YPM 28771, Anticosti Island, Québec. (a-e’’’ from Elias, 1981, fig. 15; names in [ ] are original identifications) 82 BULLETIN 314 the Beaverfoot Formation (Upper Ordovician) of southeastern British Columbia, are better known. B. cf. B. patella occurs in the following units: Selkirk Member of the Red River Formation (upper Middle or Upper Ordovician), Garson, Manitoba; members No. 1 and 3 and upper member of the Caution Creek For- mation, and member No. | of the Chasm Creek For- mation (Upper Ordovician), northern Manitoba; Gunn Member of the Stony Mountain Formation (lower to middle Ashgill), Stony Mountain, Manitoba; shaly beds at the top of the Bighorn Dolomite (Upper Or- dovician), Johnson County, Wyoming; lower member of the Vauréal Formation (?Caradoc), Anticosti Is- land, Québec; Fort Atkinson Formation (Richmond- ian), Maquoketa Group, Ossian, Iowa; and possibly in the Cape Calhoun Formation (upper Middle or Up- per Ordovician), Cape Calhoun, northwestern Green- land. This species was apparently long-lived and widely distributed in the Red River—Stony Mountain Province of North America. Family PALIPHYLLIDAE Soshkina, 1955 Genus PALIPHYLLUM Soshkina, 1955 1955. Paliphyllum Soshkina, pp. 121, 122. 1968. Paliphyllum Soshkina. B. Neuman, pp. 230, 231. 1979. Paliphyllum Soshkina. Laub, p. 123. Type Species (by original designation).—Paliphyl- lum primarium Soshkina (1955, p. 122). Upper Stolbov Suite (Upper Ordovician); Podkamennaya Tunguska River, Siberian Platform, U.S.S.R. Discussion.—Paliphyllum is characterized by an ax- ial structure composed of septal lobes and lamellae, some of which are very short, with a median lamella commonly present in at least some stages. The dis- sepimentarium has a few series of medium-sized to large dissepiments. Septal dilation is slight throughout ontogeny. B. Neuman (1968, p. 231) reported this genus from the Upper Ordovician of Siberia, Estonia, and Swe- den, and from the Llandovery (Lower Silurian) of Es- tonia. Laub (1979) described three species from the middle Llandovery Brassfield Formation in Ohio and Indiana, U.S.A. The following species are known from the Ordovician of North America: 1928. Cyathophyllum ellisense Twenhofel, p. 119, pl. 2, figs. 10-13. Upper Ordovician (Ashgill; Gamachian): Ellis Bay Formation; Anticosti Island, Québec, Canada. 1963. Phaulactis stummi Nelson, pp. 43, 44, pl. 13, figs. 7, 8a—c, 9-12. Upper Ordovician: Member No. 3 of the Chasm Creek For- mation, Churchill River Group; Hudson Bay Lowland, northern Manitoba, Canada. Paliphyllum ellisense (Twenhofel, 1928) Plate 15, figures 12—22 1928. Cyathophyllum ellisense Twenhofel, p. 119, pl. 2, figs. 10-13. Holotype (by original designation).—YPM 10388A; Twenhofel’s zone 9, Ellis Bay Formation; Ellis Bay, Anticosti Island, Québec; Twenhofel collection (Twenhofel, 1928, pl. 2, fig. 10). Paratype (by original designation).—The specimen represented by Twenhofel (1928, pl. 2, fig. 11); Twen- hofel’s zone 9, Ellis Bay Formation; Ellis Bay, Anti- costi Island, Québec; Twenhofel collection. It has not been located. Other Specimens .— (All from Twenhofel collection, Anticosti Island, Quebec.) YPM 28772, 28773; Ellis Bay Formation; west side of Ellis Bay. YPM 28774, 28775; Ellis Bay Formation; Cape Hen- ry. YPM 28776; near base of Ellis Bay Formation; coral zone above Vauréal Falls. YPM 10388B; Twenhofel’s zone 9, Ellis Bay For- mation; Ellis Bay. The specimen represented by Twenhofel (1928, pl. 2, fig. 12; it has not been located); Twenhofel’s zone 9, Ellis Bay Formation; Ellis Bay. YPM 28777, 28778; bioherm at base of Bolton’s member 6, Ellis Bay Formation; Raspberry Point. YPM 28779-28784; Twenhofel’s zone 9, Bolton’s member 6, Ellis Bay Formation; Ellis Bay. Occurrence.—Upper Ordovician (Ashgill; Gama- chian): Ellis Bay Formation; Anticosti Island, Québec, Canada. Diagnosis.—Paliphyllum with dissepimentarium consisting of one to three series of moderately large dissepiments inclined 45 degrees with respect to coral axis. Axial structure in early stage moderately to greatly dilated, consisting of a few septal lobes and lamellae—a median lamella may be present. In late stage axial structure is generally moderately complex with non-dilated to moderately dilated septal lobes and lamellae. Description of Corals.—The specimens are all in- complete at both ends. The longest fragment (YPM 10388A) is 40 mm long, and the broadest is 28 mm in diameter (YPM 28783). The maximum number of ma- jor septa observed is 42 at a diameter of 21 mm (YPM 28779). The corals are cylindrical and straight. Coarse rugae are common, and some are regularly spaced at an interval of 6 to 11 mm (PI. 15, fig. 20). Septal grooves and interseptal ridges are present on the epi- ORDOVICIAN RUGOSE CORALS: ELIAS 83 theca. In one specimen, seven offsets resulted from peripheral increase (YPM 10388B, PI. 15, figs. 21, 22s). Ontogeny and Internal Structures.—In early to in- termeuiate stages the moderately to greatly dilated ax- ial structure consists of a few septal lobes and lamel- lae, and a median lamella may be present (YPM 28782). In later stages the major septa extend almost to the axis with only a few septal lobes in some spec- imens (YPM 28776), but commonly a moderately com- plex axial structure of moderately dilated to non-di- lated septal lobes and lamellae develops. A few very short lamellae are present in all ontogenetic stages. The number of major septa at a particular diameter is shown in Text-figure 42. The septa are non-dilated, but thicken at the periphery of the coral. The cardinal septum is indistinct, and a fossula is not developed. The minor septa are very long. Some septa are inter- 9 sections from 6 corals diameter, mm Text-figure 42.—Relation between number of major septa (n) and coral diameter in Paliphyllum ellisense (Twenhofel, 1928). rupted in the dissepimentarium. In early stages the stereozone is narrow to moderately broad. In later stages a dissepimentarium develops. It attains a width of 30 (YPM 28779, Pl. 15, fig. 18) to 40 percent of the coral radius (Twenhofel, 1928, pl. 2, fig. 11), and con- sists of one to three series of dissepiments that are | to 4 mm long and inclined about 45 degrees with re- spect to the coral axis. A narrow stereozone is present on the axial side of the dissepimentarium. The tabulae are mostly complete, very thin, closely spaced, and slightly concave upward axially (YPM 28779) to moderately convex upward (YPM 28784). Complementary plates (see B. Neuman, 1969, p. 6) are present. Microstructure.—The septal fibers are well devel- oped, and the trabeculae are slightly inclined up to- ward the axis. Lamellae are not present in the ster- eozone. Discussion.—Characteristics of Baltoscandian and Siberian representatives of Paliphyllum have been summarized by Laub (1979, pp. 126-132), who de- scribed three species from the Lower Silurian Brass- field Formation of Ohio and Indiana. P. ellisense (Twenhofel, 1928) is distinguished by a dissepimen- tarium that consists of only one to three series of mod- erately large dissepiments that are inclined about 45 degrees with respect to the coral axis. P. stummi (Nelson, 1963), from the Upper Ordovician of north- ern Manitoba, differs from P. ellisense in having many series of small dissepiments, a moderately broad car- dinal fossula, and a smaller, less complex axial region. APPENDIX COLLECTING LOCALITIES The localities examined in this study are listed be- low. They are designated using U.S. Geological Sur- vey (USGS) topographic quadrangle maps in the United States (1:24,000 scale unless otherwise stated) and National Topographic System maps (1:50,000 se- ries) in Canada. Coordinates following the map name are measured first east and then north from the lower left corner of the map. Locations and stratigraphic- paleontologic data are shown in Text-figures 3, 18, and 21. The stratigraphic position of collections from the Richmond Group in the Cincinnati Arch region is sum- marized in Table 5. Cincinnati Arch Region, Ohio, Indiana, and Kentucky J/a.—Orangeburg and Maysville East Quads., Mason Co., KY: 426 mm E, 558 mm N (Orangeburg Quad.) to 411 mm E, 10 mm N (Maysville East Quad.). Type section of Bull Fork Fm. Roadcuts on E side of Hwy. 1443, 1.45 to 2.3 km N of junction with Hwy. 984, 3 km E of Springdale. Refer to USGS Quad. Maps GQ-588 and GQ-1006, and Peck (1966, pp. 19, 26-29). Table 5.—Stratigraphic position of collected intervals within the Richmond Group, Cincinnati Arch region. The first number refers to the locality and the second to the stratigraphic interval (see Text- fig. 3). For USGS collections, refer to Simmons and Oliver (1967). *“Waynes- *“Whitewater- ville” “Liberty” Elkhorn” 11b-1 3-1 lla-l Sb-1 12a-8 11b-2 3-2 12c-1 Sb-2 12a-9 14b-1 3-3 12d-1 Sb-3 12b-1 14b-2 4-2 13b-1 Sb-4 12b-2 4-3 13b-2 Sb-5 12b-3 4-4 14a-1 12a-1 13a-1 4-5 14a-2 12a-2 13a-2 5b-6 USGS loc. 4662-CO 12a-3 13b-3 5b-7 USGS loc. D1370-CO ——12a-4 14a-3 5b-8 | USGS loc. 5308-CO 12a-5 l4a-4 5b-9 USGS loc. 4468-CO 12a-6 14a-5 6c-1 USGS loc. 4545-CO 12a-7 14a-6 7b-1 USGS loc. 4760-CO 84 BULLETIN 314 /b.—Manchester Islands Quad., Adams Co., OH: 68 mm E, 497 mm N. Streamcut in Isaacs Cr. just W of Hwy. 136, 1.8 km S of intersection with Hwy. 41 at Bentonville. Refer to Kohut and Sweet (1968, pp. 1459, 1460, loc. 14). 1c.—West Union Quad., Adams Co., OH: 430 mm E, 360 mm N. Roadcut on W side of Hwy. 41, 5.45 km NE of junction with Hwy. 247N in West Union. For nearby section refer to Schmidt ef al. (1961, pp. 281-283), and Kohut and Sweet (1968, p. 1459). 2.—Bedford Quad., Trimble Co., KY: 365 mm E, 466 mm N to 336 mm E, 446 mm N. Roadcuts on N and S sides of Hwy. 42, 3.5 to 4.4 km E of Bedford. Refer to USGS Quad. Map GQ-1409, and Hattin et al. (1961, pp. 307-314, stop 3). 3.—Jeffersontown Quad., Jefferson Co., KY: 338 mm E, 51 mm N to 325 mm E, 52 mm N. Roadcuts and quarry on N side of Brush Run Rd., 0.25 to 0.65 km E of junction with Hwy. 1819, about 1.5 km WNW of Seatonville. Refer to USGS Quad. Map GQ-999, and Browne (1964, pp. 388, 390, 391, loc. 6a, 6b). 4.—Maud Quad., Nelson Co., KY: 70 mm E, 81 mm N to 59 mm E, 108 mm N. Includes type section of Bardstown Mbr., Drakes Fm. Roadcut on W side of Hwy. 150, 1.15 to 1.9 km NW of bridge over Beech Fork R., about 2 km NW of Fredericktown. Refer to USGS Quad. Map GQ-1043, Browne (1964, pp. 388, 390, loc. 1), Hatfield (1968, pl. 1, key sec. 6), Kohut and Sweet (1968, p. 1459, loc. 5), and Peterson (1970). Sa.—Whitcomb Quad., Franklin Co., IN: 24 mm E, 285 mm N to 42 mm E, 289 mm N. Roadcut on N side of Hwy. 101 at Bon Well Hill about 2 km NE of Brookville. Refer to Hay (1975), and Hay (1977, pp. 23-26). 5b.—Whitcomb Quad., Franklin Co., IN: 183 mm E, 508 mm N to 183 mm E, 532 mm N. Roadcuts on both sides of Hwy. 101 about 9.5 km NE of Brookville. Refer to Hay (1975), and Hay (1977, pp. 18-22). Sc.—Brookville Quad., Franklin Co., IN: 424 mm E, 292 mm N to 423 mm E, 305 mm N. Cut at Brookville Dam Spillway about 2 km N of Brookville. Refer to Hay (1975, p. 12) and Hay (1977, p. 27). 6a.—Lancaster Quad., Lincoln Co., KY: 55 mm E, 358 mm N. Type section of Ashlock Fm. Roadcuts on both sides of Hwy. 27, 1 km N of Dix R., about 5.5 km SW of Lancaster. Refer to USGS Quad. Map GQ-888, Weir, Greene, and Simmons (1965, pp. 9, 24, 25), and Kohut and Sweet (1968, p. 1459, loc. 2). 6b.—Paint Lick Quad., Garrard Co., KY: 13 mm E, 152 mm N. Type section of Drakes Fm. Roadcuts about 0.4 km S of East Fork, Drakes Cr., on E side of road leading NW from Vanhock Cemetery, about 3 km E of Preachersville. Refer to USGS Quad. Map GQ- 800, and Weir, Greene, and Simmons (1965, pp. 17, 30, 31). 6c.—Lancaster and Crab Orchard Quads., Lincoln Co., KY: 405 mm E, 7 mm N (Lancaster Quad.) to 410 mm E, 574 mm N (Crab Orchard Quad.). Type section of Preachersville Mbr., Drakes Fm. Roadcuts on E side of Hwy. 39, 3.7 to 3.95 km SE of Preachersville. Refer to USGS Quad. Map GQ-888, Weir, Greene, and Simmons (1965, pp. 33-35), Simmons and Oliver (1967), and Kohut and Sweet (1968, p. 1459, loc. 4). 7a.—Union City Quad., Madison Co., KY: 232 mm E, 244 mm N to 218 mm E, 235 mm N. Roadcuts on both sides of Hwy. 974, 0.8 to 1.25 km NE of Union City. Refer to USGS Quad. Map GQ- 585, and Simmons and Oliver (1967). 7b.—Union City Quad., Madison Co., KY: 52 mm E, 200 mm N to 38 mm E, 186 mm N. Roadcut on E side of road, 0.8 to 1.3 km NE of junction with Hwy. 974, about 3.5 km W of Union City. Refer to USGS Quad. Map GQ-585. 8.—Moberly Quad., Madison Co., KY: 4 mm E, 537 mm N to 43 mm E, 521 mm N. Includes type section of Terrill and Reba Mbrs., Ashlock Fm. Roadcuts on both sides of Hwy. 52, about 3 km E of Richmond. Refer to USGS Quad. Map GQ-664, and Weir, Greene, and Simmons (1965, pp. 27-29). 9.—Hedges Quad., Clark Co., KY: 140 mm E, 175 mm N to 152 mm E, 139mm N. Railroad cuts on Louisville and Nashville R.R., 1.4 to 2.4 km N of Howard Cr., 0.2 to 1.2 km SE of Agawam. Refer to USGS Quad. Map GQ-1235, Weir, Greene, and Simmons (1965, pp. 18, 19), and Kohut and Sweet (1968, p. 1460, loc. 16). /0a.—Hillsboro Quad., Fleming Co., KY: 159 mm E, 194 mm N. Roadcut on E side of road along Buttermilk Branch, 1.6 km NW of Sunset. Refer to USGS Quad. Map GQ-876. /0b.—Hillsboro Quad., Fleming Co., KY: 179 mm E, 187 mm N. Roadcut on E side of road along Buttermilk Branch, 1.1 km NW of Sunset. Refer to USGS Quad. Map GQ-876. /0c.—Hillsboro Quad., Fleming Co., KY: 168 mm E, 246 mm N. Roadcut on N side of road 1.5 km S of junction of Locust Cr. and Hillsboro Branch, 4 km WNW of Hillsboro. Refer to USGS Quad. Map GQ-876. /0d.—Hillsboro Quad., Fleming Co., KY: 290 mm E, 240 mm N. Stream cut in tributary just S of road on N side of Hillsboro Branch, 1.35 km NW of Hillsboro. Refer to USGS Quad. Map GQ-876. /0e.—Hillsboro Quad., Fleming Co., KY: 227 mm E, 310 mm N. Roadcut on N side of road 0.6 km S of Locust Cr., 3.6 km NW of Hillsboro. Refer to USGS Quad. Map GQ-876. /0f.—Hillsboro Quad., Fleming Co., KY: 319 mm E, 320 mm N. Roadcut on E side of Hwy. 111, 3 km N of Hillsboro. Refer to USGS Quad. Map GQ-876. //a.—Milan Quad., Ripley Co., IN: 16 mm E, 305 mm N to 0 mm E, 308 mm N. Roadcuts on E and W sides of Hwy. 50, 1.1 to 1.5 km W of Laughery Cr. at Versailles. Refer to Hattin er al. (1961, pp. 334, 347-349), and Hatfield (1968, pl. 1, key sec. 2). //b-1.—Milan Quad., Ripley Co., IN: 80 mm E, 372 mm N. Stream cut on S side of Falling Timber Cr., 0.4 km upstream from Laughery Cr., about 2.3 km NE of Versailles. 1/b-2.—Milan Quad., Ripley Co., IN: 103 mm E, 379 mm N. Stream cuts on S and N sides of Falling Timber Cr., 1.1 to 1.2 km upstream from Laughery Cr., about 2.8 km NE of Versailles. 71 b-3.—Milan Quad., Ripley Co., IN: 108 mm E, 390 mm N. Stream cut on N side of Falling Timber Cr., 1.4 to 1.5 km upstream from Laughery Cr., about 3.1 km NE of Versailles. 12a.—Richmond Quad., Wayne Co., IN: 364 mm E, 448 mm N. Stream cut at Thistlewaite Falls on West Fork of Whitewater R. just S of bridge in Spring Grove. Refer to Cumings (1908, p. 662), and Hay (1975, p. 23). /2b.—Richmond and New Paris Quads., Wayne Co., IN: 392 mm E, 103 mm N (Richmond Quad.) to 37 mm E, 134 mm N (New Paris Quad.). Stream cuts along Elkhorn Cr. between Straight Line Rd. and Hwy. 227, about 6 km S of Richmond. Refer to Cumings (1908, pp. 657, 658, 660), and Hay (1975, p. 26). /2c.—Richmond Quad., Wayne Co., IN: 175 mm E, 156 mm N. Stream cuts at Blue Clay Falls on creek just S of Hunt Rd., 0.55 km W of Salisbury Rd., about 7 km SW of Richmond. Refer to Hay (1975, p. 20). /2d.—Liberty Quad., Wayne Co., IN: 148 mm E, 496 mm N to 152 mm E, 501 mm N. Roadcut on E side of Smithfield Rd., 0.1 to 0.25 km N of intersection with Potter Shop Rd., 0.4 km E of Abing- ton. For nearby section refer to Hay (1975, p. 19). /3a.—Fairborn Quad., Greene Co., OH: 128 mm E, 211 mm N. Railroad cut primarily on S side of New York Central R.R., 0.1 km N of Wright Bros. Memorial, about 6 km SW of Fairborn. Refer to Utgaard and Perry (1964, p. 35, loc. 21), and Kohut and Sweet (1968, p. 1459, loc. 10). /3b.—Fairborn Quad., Greene Co., OH: 119 mm E, 215 mm N. ORDOVICIAN RUGOSE CORALS: ELIAS 85 Cut on S bank of Mad R., 0.1 km SW of Huffman Dam, about 6 km SW of Fairborn. Refer to Kohut and Sweet (1968, p. 1459, loc. 10). /4a.—Clarksville Quad., Clinton Co., OH: 253 mm E, 83 mm N to 263 mm E, 65 mm N. Cut on N side of Cowan Cr., 0.2 to 0.75 km downstream from Cowan L. spillway, about 4.7 km ESE of Clarksville. 14b.—Oregonia Quad., Warren Co., OH: 70 mm E, 195 mm N to 63 mm E, 184 mm N. Roadcuts primarily on W side of road just S of Hwy. I71 leading to picnic area on Little Miami R., about 1.7 km NW of Ft. Ancient State Memorial. Refer to Wolford (1930, pp. 304-307), and Kohut and Sweet (1968, p. 1459, loc. 11). Burkesville, Kentucky 15a.—Waterview Quad., Cumberland Co., KY: 452 mm E, 104 mm N. Roadcut on E side of Hwy. 61, 1.3 km S of junction with Hwy. 90E at Burkesville. Refer to USGS Quad. Map GQ-286, and for nearby section refer to Jillson (1951). /5b.—Waterview Quad., Cumberland Co., KY: 412 mm E, 211 mm N. Roadcut on S side of new Hwy. 90, 2.2 km E of junction with Hwy. 691, about 1.3 km NW of Burkesville. Refer to USGS Quad. Map GQ-286. 15c.—Waterview Quad., Cumberland Co., KY: 422 mm E, 215 mm N. Roadcut on N side of new Hwy. 90, 2.4 km E of junction with Hwy. 691, about 1.2 km NW of Burkesville. Refer to USGS Quad. Map GQ-286. 15d.—Waterview Quad., Cumberland Co., KY: 330 mm E, 205 mm N. Outcrop just E of Cary house, 0.4 km N of junction of Hwys. 90 and 691, about 3.5 km W of Burkesville. Refer to USGS Quad. Map GQ-286, and Jillson (1953). Goodlettsville-Gallatin Area, Tennessee 16a.—Goodlettsville Quad., Sumner Co., TN: 128 mm E, 533 mm N and 134 mm E, 542 mm N. Roadcuts on W and E sides of Hwy. 165, 2.4 km N of Goodlettsville N interchange. For nearby sections refer to Bassler (1932, p. 122), and C. W. Wilson (1949, pp. 234, 236, sec. 5). 16b.—White House Quad., Sumner Co., TN: 138 mm E, 4 mm N. Roadcut on W side of Hwy. 165, 3.45 km N of Goodlettsville N interchange. For nearby sections refer to Bassler (1932, p. 122), and C. W. Wilson (1949, pp. 234, 236, sec. 5). 16c.—Gallatin Quad., Sumner Co., TN: 254 mm E, 414 mm N. Roadcut on W side of Dobbins Pike, 2.75 km S of Graball. For nearby sections refer to Bassler (1932, p. 127). Little Bay de Noc, Michigan 17a.—Peninsula Point Quad. (1:62,500), Delta Co., MI: 28 mm E, 420 mm N. Outcrop on E shore of Little Bay de Noc just W of road, 2.3 km N of Stonington. Refer to Foerste (1918, p. 98, Rhein- holdson sec.), Hussey (1926, pp. 116, 117, 133, 142, loc. 17), and Hussey (1950, pp. 16-20, stop 7). 17b.—Rapid River Quad. (1:62,500), Delta Co., MI: 168 mm E, 59 mm N. Federal Forest Quarry No. 2 just W of Co. Hwy. 511, 0.5 km S of Stonington lookout tower. Refer to Kesling (1975, p. 8, loc. 4, pl. 1, figs. 3, 4, p. 27, map 1), and for nearby section refer to Hussey (1926, pp. 116, 117, 146, loc. 11), and Hussey (1950, pp. 21, 22, stop 8). 17c.—Rapid River Quad. (1:62,500), Delta Co., MI: 169 mm E, 75 mm N. Outcrops on E and W sides of road, 0.4 km N of inter- section near Stonington lookout tower. Refer to Hussey (1926, pp. 116, 117, 145, 146, loc. 12). Drummond Island, Michigan /8a.—Drummond SE Quad., Drummond Is., MI: 135 mm E, 416 mm N and 115 mm E, 411 mm N. Samples collected at exposure on shore 0.3 km SE of Raynolds Point; paleocurrent data collected on shore in NE part of Raynolds Bay, 0.3 km SW of Raynolds Pt. For nearby section refer to Hussey (1952, pp. 49, 50). 78b.—Drummond Quad., Drummond Is., MI: 383 mm E, 477 mm N. Exposure on shore 0.3 km E of Poe Point. Refer to Hussey (1952, pp. 50, 51). /8c.—Drummond Quad., Drummond Is., MI: 86 mm E, 437 mm N. Exposure on shore at Hay Point. For nearby section refer to Hussey (1952, p. 50). Manitoulin Island, Ontario /9a.—Little Current Sheet (No. 41 H/13), Manitoulin Is., Ont.: 184 mm E, 284 mm N. Roadcuts on both sides of Hwy. 68, 4.9 km SE of Sheguiandah. Refer to Ontario Division of Mines (ODM) Map 2247. 19b.—Little Current Sheet (No. 41 H/13), Manitoulin Is., Ont.: 227 mm E, 283 mm N. Roadcut on Hwy. 68, 7.1 km SE of She- guiandah. Refer to ODM Map 2247. 19c.—Little Current Sheet (No. 41 H/13), Manitoulin Is., Ont.: 28 mm E, 325 mm N. Roadcut on S side of road, 4.5 km W of Sheguiandah. Refer to ODM Map 2247. 19d.—Kagawong Sheet (No. 41 G/16), Manitoulin Is., Ont.: 375 mm E, 344 mm N. Roadcut on W side of road into Kagawong, 0.3 km N of junction with Hwy. 540. Refer to ODM Map 2246, Foerste (1916, p. 110, loc. 40), and Liberty and Shelden (1968, p. 7, stop 1). 19e.—Kagawong Sheet (No. 41 G/16), Manitoulin Is., Ont.: 613 mm E, 331 mm N. Roadcut on E side of Hwy. 540, 1.4 km N of Honora. Refer to ODM Map 2246. 19f.—Kagawong Sheet (No. 41 G/16), Manitoulin Is., Ont.: 384 mm E, 324 mm N. Roadcut on N and S sides of Hwy. 540, | km SE of junction with road into Kagawong. Refer to ODM Map 2246, and for nearby section refer to Foerste (1916, pp. 108, 109, loc. 38). M6/a.—Little Current Sheet (No. 41 H/13), Manitoulin Is., Ont.: 293 mm E, 2 mm N. Laurentian Univ. collection. Refer to ODM Map 2247. M75.—Little Current Sheet (No. 41 H/13), Manitoulin Is., Ont.: 60 mm E, 283 mm N. Laurentian Univ. collection at ditch on SE corner at intersection of E-W and N-S roads, | km E of Pike Lake. Refer to ODM Map 2247. Missouri 20a.—Cape Girardeau NE Quad., Cape Girardeau Co., MO: 44 mm E, 276 mm N. Type section of Leemon Formation. Outcrop in gully behind barn on Short’s farm. Refer to Amsden (1974, pp. 19-21, loc. K), and Thompson and Satterfield (1975, pp. 76, 77, loc. 3). 20b.—Neelys Landing Quad., Cape Girardeau Co., MO: 71 mm E, 251 mm N. Outcrops on Blue Shawnee Creek, 1.7 km E of New Wells. Refer to Amsden (1974, pp. 20-22, loc. U), and Thompson and Satterfield (1975, pp. 79, 80, loc. 4). 2/a.—Clarksville Quad., Pike Co., MO: 326 mm E, 572 mm N. 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Surv., Prof. Paper 1126-D, 8 pp. Sweet, W. C., and Bergstrom, S. M. 1971. The American Upper Ordovician Standard: XIII, A re- vised time-stratigraphic classification of North American upper Middle and Upper Ordovician rocks. Geol. Soc. Am., Bull., vol. 82, No. 3, pp. 613-628. Sweet, W. C., Ethington, R. L., and Barnes, C. R. 1971. North American Middle and Upper Ordovician conodont faunas. Geol. Soc. Am., Mem. 127, pp. 163-193. Teichert, C. 1937. Ordovician and Silurian faunas from Arctic Canada. 5th Thule Exped., 1921-1924, Rept., vol. 1, No. 5, 169 pp., 24 pls. Templeton, J. S., and Willman, H. B. 1963. Champlainian Series (Middle Ordovician) in Illinois. UWh- nois State Geol. Surv., Bull. 89, 260 pp. Thompson, T. L., and Satterfield, I. R. 1975. Stratigraphy and conodont biostratigraphy of strata con- tiguous to the Ordovician-Silurian boundary in eastern Missouri. Missouri Geol. Surv., Rept. Invest., No. 57, pp. 61-108. Troedsson, G. 1928. On the Upper and Middle Ordovician faunas of northern Greenland, Part 2. Medd. Grgnland, vol. 72, No. 5, 197 pp., 56 pls. Twenhofel, W. H. 1914. The Anticosti Island faunas. Geol. Surv. Canada, Mus. Bull. 3 (Geol. Ser. 19), 39 pp., | pl. 1928. Geology of Anticosti Island. Geol. Surv. Canada, Mem. 154, 481 pp., 60 pls. Twenhofel, W. H., Bridge, J., Cloud, P. E., Jr., Cooper, B. N., Cooper, G. A., Cumings, E. R., Cullison, J. S., Dunbar, C. O., Kay, M., Liberty, B. A., McFarlan, A. C., Rodgers, J., Whittington, H. B., Wilson, A. E., and Wilson, C. W., Jr. 1954. Correlation of the Ordovician formations of North Amer- ica. Geol. Soc. Am., Bull., vol. 65, No. 3, pp. 247-298. Ulrich, E. O. 1879. Descriptions of new genera and species of fossils from the Lower Silurian about Cincinnati. Cincinnati Soc. Nat. Hist., J., vol. 2, pp. 8-30, pl. 7. Utgaard, J., and Perry, T. G. 1964. Trepostomatous bryozoan fauna of the upper part of the Whitewater Formation (Cincinnatian) of eastern Indiana and western Ohio. Indiana Geol. Sury., Bull. 33, 111 pp., 23 pls. Votaw, R. B. 1981. Conodonts from the Middle and Upper Ordovician of the Upper Peninsula of Michigan. Geol. Soc. Am., Abstr. w. Progr., vol. 13, No. 6, p. 320. Votaw, R. B., and Kolata, D. 1981. Preliminary lithostratigraphy and biostratigraphy of the Maquoketa Group (Upper Ordovician), northern Illinois. Geol. Soc. Am., Abstr. w. Progr., vol. 13, No. 6, p. 320. Wedekind, P. R. 1927. Die Zoantharia Rugosa von Gotland (besonders Nord- gotland); Nebst Bemerkungen zur Biostratigraphie des Gotlandium. Sveriges Geol. Under., ser. Ca, No. 19, 94 pp., 30 pls. Weir, G. W., Greene, R. C., and Simmons, G. C. 1965. Calloway Creek Limestone and Ashlock and Drake For- mations (Upper Ordovician) in south-central Kentucky. U.S. Geol. Surv., Bull. 1224-D, 36 pp. Weiss, M. P., and Norman, C. E. 1960. The American Upper Ordovician Standard; II. Develop- ment of stratigraphic classification of Ordovician rocks in the Cincinnati region. Ohio Geol. Surv., Inf. Circ. 26, 14 pp., | pl. Wells, J. W. 1957. Corals, pp. 773-782 in Ladd, H. S. (ed.), Treatise on ma- rine ecology and paleoecology, vol. 2, Paleoecology. Geol. Soc. Am., Mem. 67, vol. 2, 1077 pp. 1970. Problems of annual and daily growth-rings in corals, Chapter 1, pp. 3-9 in Runcorn, S. K. (ed.), Palaeogeo- physics. Academic Press, 518 pp. Whiteaves, J. F. 1895. Systematic list, with references, of the fossils of the Hud- son River or Cincinnati at Stony Mountain, Manitoba. Geol. Surv. Canada, Palaeozoic Fossils, vol. 3, No. 2, pp. 111-128. 1896. Descriptions of eight new species of fossils from the (Ga- lena) Trenton limestones of Lake Winnipeg and the Red River valley. Canadian Rec. Sci., vol. 6, No. 7, pp. 387-397. Willman, H. B. 1973. Rock stratigraphy of the Silurian System in northeastern and northwestern Illinois. Mlinois State Geol. Surv., Circ. 479, 5S pp. Willman, H. B., and Atherton, E. 1975. Silurian System. Illinois State Geol. Sury., Bull. 95, pp. 87-104. Willman, H. B., and Buschbach, T. C. 1975. Ordovician System. Illinois State Geol. Surv., Bull. 95, pp. 47-87. Wilson, A. E. 1926. An Upper Ordovician fauna from the Rocky Mountains, British Columbia. Geol. Surv. Canada, Mus. Bull. 44, pp. 1-34, 8 pls. Wilson, C. W., Jr. 1935. The pre-Chattanooga development of the Nashville Dome. J. Geol., vol. 43, No. 5, pp. 449-481. 1948. The geology of Nashville, Tennessee. Tennessee Div. Geol., Bull. 53, 172 pp., 29 pls. 1949. Pre-Chattanooga stratigraphy in central Tennessee. Ten- nessee Div. Geol., Bull. 56, 407 pp., 28 pls. Winchell, N. H., and Schuchert, C. 1895. Sponges, graptolites, and corals from the Lower Silurian of Minnesota, Chapter 3, pp. 55-95 in The Geology of Minnesota, vol. 3, No. 1, Paleontology. Minnesota Geol. Nat. Hist. Surv., 474 pp., 41 pls. ORDOVICIAN RUGOSE CORALS: ELIAS 93 Winchell, N. H., and Ulrich, E. O. 1897. The Lower Silurian deposits of the upper Mississippi prov- ince; a correlation of the strata with those in the Cincin- nati, Tennessee, New York, and Canadian provinces, and the stratigraphic and geographic distribution of the fos- sils. Minnesota Geol. Nat. Hist. Surv., Final Rept., vol. 3, pt. 2, pp. Ixxxili—cxxviil. Wolford, J. J. 1930. The stratigraphy of the Oregonia—-Ft. Ancient region, southwestern Ohio. Ohio J. Sci., vol. 30, No. 5, pp. 301-308. Wright, A. D. 1968. A westward extension of the upper Ashgillian Hirnantia fauna. Lethaia, vol. 1, No. 4, pp. 352-367. PLATES Exterior views are of specimens coated with ammonium chloride. A stereopair is denoted by ‘‘s’’ following the figure number. Transverse and longitudinal sections are negative prints of thin sections unless otherwise stated. Transverse sections are oriented as they appear looking from the top of the coral towards the tip. Small numbers and lines beside exterior views and longitudinal sections refer to positions and figure numbers of illustrated sections. When the interval from which a specimen was collected is given, the first number indicates the locality and the second designates the stratigraphic interval (see ‘‘Appendix: Collecting Localities’’, and Text-figs. 3, 18, 21). If this publication is photo-reduced, note that in the original the dimensions of plates, excluding margins, are 7 inches by 9 inches. 94 BULLETIN 314 EXPLANATION OF PLATE | Figure Page 1=41. ‘Streptelasma:divaricans/(Nicholsoms-I875b)) ~ Sp6 vec tere oes © ici eke oer oie) srave retake Gciater overeat pre eI eI Aes aera ee ee eee 25555 (Richmond Group; Cincinnati Arch region) 1-19. Axial region comparative scale and values (small numbers 5, 10. . . 95), transverse sections, <3 (see p. 26). 1, UCGM 45072; interval 12a-1. 2, UCGM 45061; interval 11b-1. 3, UCGM 45014; interval 4-2. 4, UCGM 45037; interval S5b-2. 5, UCGM 45137; interval 13b-2. 6, UCGM 45004; interval 2-1. 7, UCGM 45133; interval 13b-1. 8, UCGM 45074; interval 12a-1. 9, UCGM 45028; interval 5b-1. 10, UCGM 45054; interval 5b-9. 11, UCGM 45084; interval 12a-2. 12, UCGM 45008; interval 3-2. 13, UCGM 45611; interval 13a-1. 14, UCGM 45018; interval 4-3. 15, UCGM 45057; interval 10c-1. 16, UCGM 45020; interval 4-4. 1/7, UCGM 45086; interval 12a-2. 18, UCGM 45034; interval 5b-2. 19, UCGM 45019; interval 4-3. 20-22. UCGM 45072; interval 12a-1. 20, exterior alar view, cardinal side left, <1 (see p. 23). 2/, 22, transverse sections, cardinal side down, x3. 23-26. UCGM 45074; interval 12a-1. 23, exterior alar view, cardinal side right, x1. 24-26, transverse sections, cardinal side down, 3. 27-29. UCGM 45084; interval 12a-2. 27, exterior view, X1 (see p. 23). 28, 29, transverse sections, <3. 30-32. UCGM 45018; interval 4-3. 30, exterior view, <1 (see p. 23). 3/, 32, transverse sections, <3. 33-36. UCGM 45086; interval 12a-2. 33, exterior view, cardinal side left, x 1 (see p. 23). 34-36, transverse sections, cardinal side down, x3. 37-41. UCGM 45034; interval 5b-2. 37, exterior alar view, cardinal side left, x 1. 38-4/, transverse sections, cardinal side down, x3. BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 81 PLATE 1 2 ‘/) oe Ra “hbehddy™™ 15 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 81 PLATE 2 Figure Page =| OmmeStreptelasmaldivaricans (Nicholson! S75b) ie epee eye eee eee eee eee elite terete ele ete ee ete teerereereeety O (Richmond Group; Cincinnati Arch region) 14. UCGM 45128; interval 13a-2; transverse sections, <3 (see p. 23). 5. USNM 84868a [syntype of S. divaricans-angustatum Foerste (1909)]; ‘Whitewater’ strata, Osgood, Indiana; trans- verse section, x3. 6, 7. UCGM 45013; interval 4-2. 6, exterior alar view, cardinal side left, 1. 7, longitudinal section, cardinal side left, xh, 8. UCGM 45145; ‘‘Whitewater”’ strata, Hueston Woods Park, Oxford, Ohio; longitudinal section, cardinal side right, Sesh 9. UCGM 45024; interval 4-5; transverse photomicrograph, late ontogenetic stage, dilated major and minor septa in lateral contact in stereozone, x31. 10. UCGM 45080; interval 12a-2; transverse photomicrograph, late ontogenetic stage, non-dilated major and minor septa separated by U-shaped lamellae in stereozone, 31. 11. UCGM 45646; interval 12a-5; exterior view, <1 (blastogeny shown in Text-fig. 26; see p. 23). 12, 13. UCGM 45093; interval 12a-4; transverse sections, 3. /2, increase demonstrated by incomplete wall between two corallites on left. 73, corallites separated later in ontogeny. 14, 15s. USNM 311660; ‘‘Whitewater”’ strata, NW of Oxford, Ohio. /4, transverse section showing opening in wall devel- oping between two central corallites, x3. /5s, exterior view of calices showing complete connection between two central corallites later in ontogeny, 1. 16s. USNM 311661; ‘‘Whitewater”’ strata, NW of Oxford, Ohio; exterior view showing rejuvenance in calice of right ORDOVICIAN RUGOSE CORALS: ELIAS EXPLANATION OF PLATE 2 corallum, x1. 96 BULLETIN 314 EXPLANATION OF PLATE 3 Figure Page 1-23. |\Streptelasma’ divaricans; (Nicholson. 11875) «<0: :s1-evej0 ce snte: 209% «ieee = ~ r | pis f ht 4 MARE eT, it sy! at PLATE 10 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 81 = = hi i Uh nN ORDOVICIAN RUGOSE CORALS: ELIAS 103 EXPLANATION OF PLATE 10 Figure Page 1-28. Grewingkia canadensis (Billings, 1862) ..........- 2-6... eee ee cece eee eee eee eee tenet eee eee tees 66 (Richmond Group: 1-7, Goodlettsville-Gallatin area, Tennessee; 9-17, Drummond Island, Michigan; 18-27, Manitoulin Island, Ontario; 28, Meaford, Ontario. Maquoketa Group: 8, Little Sturgeon Bay, Wisconsin) 1-5. UCGM 45505: interval 16a-1. /, exterior alar view, cardinal side left, x1 (see p. 28). 2-5, transverse sections, cardinal side down, 1.5. 6. UCGM 45519; interval 16b-2; transverse section, cardinal side down, 1.5. 7. UCGM 45518; interval 16b-2; transverse section, cardinal side down, =1.5. 8. USNM 311653; top of Maquoketa Group; transverse section, cardinal side down, x2. 1. GSC 1983h, i (lectotype); upper mbr., Georgian Bay Fm. 9 (GSC 1983h), polished longitudinal section, cardinal side left, x1. 10, 11 (GSC 1983i), transverse sections, cardinal side down, 1.5. 12-14. UCGM 45540; interval 18-1; transverse sections, cardinal side down, 1.5. 15-17. UMMP 26927 [holotype of Streptelasma arcticum drummondense Stumm (1963)]; upper Meaford beds, upper mbr., Georgian Bay Fm., Potaganissing Bay, Poe Point. /5, exterior alar view, cardinal side right, <1 (see p. 31). 16, 17, transverse sections, cardinal side down, 1.5. 18-23. GSC 66641; locality M6la. /8, exterior cardinal view, <1 (see p. 33). 19, exterior alar view, cardinal side left, x1 (see p. 33). 20-23, transverse sections, cardinal side down, 1.5. 24-27. UCGM 45585; interval 19d-1. 24, exterior alar view, cardinal side left, x1 (see p. 33). 25-27, transverse sections, cardinal side down, 1.5. 28. GSC 8531; upper Georgian Bay Fm.; transverse section, cardinal side down, 1.5. 104 Figure I-11. BULLETIN 314 EXPLANATION OF PLATE 11 Grewingkia, deltemsis 1... Sp\ sc <.sja555.4 eiad seein dics eve-w) ove stese oye epctehe ey eynis tein o eVein ain) 0/00 %a\\e icy eyeoray eis evcievere) © efelsye Cretaateteiceltetstells sient seit (Ogontz Mbr., Stonington Fm., interval 17a-1, Delta Co., Michigan) 1-8. UCGM 45602 (holotype). /, exterior alar view, cardinal side left, <1 (see p. 30). 2—5, transverse sections, cardinal side down, 1.5. 6, 7, longitudinal sections, cardinal side left, «1.5. 8, transverse photomicrograph, Holocene algal borings in outer coral wall, x46 (see p. 30). 9-11. UCGM 45596 (paratype). 9, exterior alar view, cardinal side right, <1 (see p. 30). /0, 71, transverse sections, cardinal side down, 1.5. Grewingkia!rustica (Billings, U858a)! src ctersv.o erste oe 5 «. ecapeuesei se exocebedel ol ohele iets @ 0\=\sioley2)s 1 Re eres Se eect elsie iets creo eer ae eee eet (Richmond Group: 12-23, 28, 29, Snake Island, Lake St. John, Québec; 24-27, Manitoulin Island, Ontario) 12. GSC $822c (lectotype); polished transverse section, cardinal side down, 1.5. 13-15. GSC 8527; x1.5. 13, longitudinal section, cardinal side right. /4, /5, transverse sections, cardinal side down. 16-19. GSC 8527c. 16, exterior alar view, cardinal side right, «1 (see p. 35). 17-19, transverse sections, cardinal side down, x1.5. 20-23. GSC 8527n. 20, exterior alar view, cardinal side right, x | (see p. 35). 2/-23, transverse sections, cardinal side down, alts 24-27. UCGM 45592; interval 19b-1. 24, exterior alar view, cardinal side left, <1 (see p. 33). 25-27, transverse sections, cardinal side down, 1.5. 28s. GSC 8527a; exterior view of calice, cardinal side down, x1.5. 29. GSC 8527c; transverse photomicrograph, age of algal borings in outer coral wall uncertain, x46 (see p. 35). BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 81 PLATE 11 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 81 PLATE 12 Figure 1-6. 7-21. ORDOVICIAN RUGOSE CORALS: ELIAS 105 EXPLANATION OF PLATE 12 Page Grewingkiapenobscotensisim ssp siete reel eee seein e iia) rereerielel ttt tater rier 72 (unnamed Ashgill formation, Penobscot Co., Maine) 1, 2. USNM 311751 (paratype); 2.5. 7, longitudinal section. 2, transverse section. 3-5. USNM 311748 (holotype); x2.5. 3, longitudinal section. 4, 5, transverse sections. 6. USNM 311757 (paratype); transverse section, <2.5. Grewinpkiagpulchellar (Bilin eseml S05) msewtrete aerial rteretentedeiretelerstelelelere kes serete tee ers teil aialens rotate iota leheeretcheryenste tele pne te ete tetetetetere tere ole 73 (7-19, Anticosti Island, Québec; 20, 21, unnamed Ashgill unit, near Ashland, Maine) 7-10. GSC 1989h; upper mbr., Vauréal Fm. 7, exterior cardinal view, <1 (see p. 46). 8, exterior alar view, cardinal side left, <1 (see p. 46). 9, /0, transverse sections, cardinal side down, x2.5. 11-14. YPM 28728; Ellis Bay Fm. //, exterior alar view, cardinal side left, <1 (see p. 46). 12-/4 (YPM 28728A-C), transverse sections, cardinal side down, 2.5. 15-18. YPM 28726; Ellis Bay Fm. /5, exterior alar view, cardinal side right, <1 (see p. 46). 16-18 (YPM 28726A-C), transverse sections, cardinal side down, 2.5. 19. YPM 28734A; Ellis Bay Fm.; longitudinal section, cardinal side right, <2.5. 20, 21. USNM 311717; transverse sections, cardinal side down, 2.5. Gre wat KUL SP Seas ciecesete acne seas TT er TORU FNS eRe nse ey clos 2 cicus e dev cp eV oh epeVohe lane ust vete (oper swaneusteysvensiterenacaseysisushes stsleverefekekepsesyar=aeKes=totenagets 74 (White Head Fm., Perce, Québec) 22-24. YPM 28762A-C; transverse sections, x2 25. USNM 311638; transverse section, <2.5. 106 Figure 1-7. 10-14. BULLETIN 314 EXPLANATION OF PLATE 13 Lobocorallium(trilobatum' vaurealense (T'wenhofel,, 1928) oc... clece «ce cxecteie erie oreieve, = eps: «\ea.+ ee icteric ciel cele ecient eee 75) (1-6, upper mbr., Vaureal Fm., Anticosti Island, Québec; 7, White Head Fm., Percé, Québec) Is, 2. YPM 20482 (holotype). /s, exterior alar view, cardinal side right, x0.5 (see p. 46). 2, polished longitudinal section, cardinal side left, «1. 3, 4. GSC 66590; transverse sections, cardinal side down, *1.5 6. GSC 66591; transverse sections, cardinal side down, =1.5 7. USNM 311635; transverse section, cardinal side down, x1 ECAC) UR ATTIC AEG) 0 em ERP ERS Cee oc Sic ence RCNP ne arch eR cr Rr ots a ot eM eta Rin em adononcd.cs 41, 77 (unnamed Ashgill formation, Penobscot Co., Maine) 8. USNM 311759; transverse section, <2.5. 9. USNM 311758; transverse section, cardinal side probably down, 2.5. BodophrylhumiShorei)n. 'Spioiaicis gio lese exesesevle <2 etevsene sp aravsin en clieeelalayeta elebolescte a: aareieicheve njeetelsiilevovechee!=\e Tele lseKeie Me eRe Tee RC eR RoR 395i UCGM 45613 (holotype); Leemon Fm., locality 20a, Cape Girardeau Co., Missouri; transverse sections, cardinal side down, x4. immediately below calice, several mm above 5. Aad BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 81 PLATE 13 at Vi = gte x, Yiu PLATE 14 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 81 Ay 4 Figure 7-9. 10-16. 17-24. ORDOVICIAN RUGOSE CORALS: ELIAS 107 EXPLANATION OF PLATE 14 Page Bodophyllumi mewn ami yn S ps ops ce se aie 5) sis sys veer sies nc siseictebe ema clade etan cele 12 (Greenlandic. o seccadesres sts scneconeraerssssiaussaes 48,49,60,74,76,77 (Capel Calhoun, f.2io.r. 2. cc ce csn nde sccnenseesessseeecsvssies sueogeeeseseeaes 82 Grewingkia Dybowski (1873).................. 18,30,48-52,56,61,64, 65,66, 69,75,77,80 fanguined (Schettense1933))n.csce-ssensesccs sees ses: seers essen 65 bilateralismb Neuman (1969) racesecesteesecse eneceeee enact eee Til canadensis (Billings, 1862)......... 3,7-10 ...... 13-22,23,25,26, 28 29,3 1-33 ,34,35,48,50,51,65,66-69, 72 clhaGacanadensis (Billings, 1862) )n...c---- esseeeeecsd-ee seeeee ee occ 67 GAN AGG Ty Sas osseesnascososocobecaee 11 ...... 29,30,48,50,51,69,70 ay sita(Meeks, 1865) sx. c-caescnscse-ascessn-eneecaceesecusions 64,66,75,76 ltamaieea TEES (CICS) casioseccscacssasasossdnoacanoesonbaoesecnecaeeoeTe il Penobscotensis N. SP. ........0ereeeeee Py Bence 41,48 ,49,65,72,73 pulchella (Billings, 1865)......... 1 eeeee 41,45 46,48 ,49,63,73,74 robustan(Whiteavess, 1896) e..cscc-ecn-saesee sere scoses-roctes 64,66,76 rustica (Billings, 1858a) .... 11 .....33,35,48,50,51,65,66,69, 70-72 QDs -sosansnsobsesousousdsascangabaD{codocooonCedasoanod 1 Pepercee 42,48 ,49,74 Gos (Cloysyaterr (WEIS) pocqnconbaccaasadoasococdassaccad:GobCceacsocnodedeecoode 66 GrewingkiaGusp. cess. cuccesuseusisacin on cee ssee decenosenan sero saneneaeeCeees 34 GSC (Geological Survey of Canada) 6,32—34 45,53 ,59-67,69, 71-73,75,76,81,96,99, 103-106 Guensburgicollectioniiecans1-.--nentes sonese ene soeee see sceace eeeeseeee ses 61 (GupStadth (O58) ee cece cates sem cosa sen ctoa tines sieereereteacesopapleaeisin ese eevee 35 In erereiral IME ONS: Geceoooo}ocsacnsaoaconsaActonncranckenasasodeeccasacecnoc 27 FRAN (GY WA eedecccantnestitaaucbossscerieceenbccon ce anncBnnsaanced 50,52,57,61,65 Mal CISS2) eso ee scette. se cscce sectessucactaaccusweadessaiceiae 53,56 ,66,69 ALY SILE Sum ere ene co sestees aceeciee harveyi, Deiracorallium Flattield|((\1968)) <2sccc20.2.----c0-ces-0e- attinvetals (96) iss: cccaceecntsiac seesennsescisescneancessseeet dest wees aw Kins Petes COME Se seise cio vie crea deena osc elon ce eitosee waite sealer Hay (1975) Hay (1977) haysii Grewingkia Streptelasma Hebertella insculpta Helicelasma B. Neuman (1969)......... 18,49,51,52,60,6/,65,66,69 aire LIVES (OE 310) o coseoneeonsecansndosodsed Gx. 55.6 35 36,4861 62,63 Helicelasma selectum (Billings, 1865)...... Oyres:: 42,45 46,48 ,49,61,62,63,74 Siagaliase 1s}, Nig eMt (WCE) caccoopsoonnnpsnonnoonsneondopoaoacsbeps6sce0 60 SpwALScruttone(975)) sncoscscoecsscsecnnseccccsencteoonscuce starsat 49,74 Is HITT GIS EIS) erccoaseacseastcHeeancna sea ic crcbensce nn snateaaenececonbacecucseaccccces 6 FATAL 9S 6) ie rset cose ston «c satetaaeeneneseanttececsiladcacasmacdetnn de tectepeee eee 6 irnantiasaunay ates ces eens esos Cone eee Bas 38,42,45,50 Hlirnantianestagewecen cress cccocesese cece occa toes en ese eee 38 ,39,42,45 Holophragma anticonvexa Okulitch (1943) ..............0..000- 80,81 EL OLO DANGLING LSP ame esa svoser cue cace eee eae en RRC Sa oO 80 Holiedahlinaysulcatamencc--corste cen cern eee ene 23 Honorat Group FPOWEN(U969) fee ore pee tesosons eee ne seen Ce CERES Hudson Basin Elusseyacollectione se. ctmcnwcncaconesaseeesesene sane cece sens Soe eer 67 HUSSEY J (11926) spe ccm steee terest eee eee core coe con eeaeee eee 29,30,85 ELUSSe yA (950) ip seme eee en cos Se se cc nee soe cons wome ou cea ee cena 29,30,85 1s CHSRY=5 971 CIE Y) i ee anarekenenn tocscoadouenones baresGenearaacadsceocon ce 30,31,85 LCAGUS SC CNAQUNINUSR aches caveees reise cs accededee oe Secs sce see aeT eee 44 Mlinoisee 2 eee 6-8 29,35 36, 37-40,45,47,48,51,60,62,63 Alexander County mecenccesessecece esate eueeeerse ear aen oe eeee 61 CalhouniGountyie tes eee 40 Sterling Thebes Wil COUNTY. 52s. 2050 eieseas char as Maccdeconaee cnn 740,57 Illinois Basin Tnidian deraes see nqoovacedeass os Jac saseosnacsacosnoss Moore’s Hill (OLY -{070)s ll enna sean aacscranccresecen stceancpeadboacinarereecLicacoctesdaoncasosc Westport Inghamiand)Wiarights (197.0) eceensccescceseeeeteeece ee eeeee ee ceeeeeee 6,38 insculptawHebertellawmnes cccese eee ee 18 TASC, SUAG ATA YE) ccosecbosonnsocaosscnocoanoscoHenHaesencor 66,68 ,69 WAT. NOU EO AOINS. ccccccoacodcncbeccoanaconsaaccenoonjoaneanceatconce 44 TO Wale eee. Sos ee venesn aero tenes 7,19,29 35,36, 44,48 ,62,63,81 GlaytontG ounty, ccsse- eon eewneaseses tose sscads sacesmetn soca meee 35,61 Clermont Township)... scs-ceseosscssaceece one rere eee 62 Rayette! Countyic.ccntesscostees ees cee eee 35,61 Ossian Preston Winneshieki County necesers ee eee eee eee 80 HS Et is onan inet oa Bese pec En tec ue Da ERE eine SSericodbunece paAtcaaonBnobe 42 Ivanovskiyi(1962)).sccccssuhsences smote tticee te osetee seed. eee ee il, [Van OVSKIVA(L963)\-2.2 sc ceoccecae teen eee eee 52 IMAYoy a (6X0) | Fre aaeprencaoee concesER cont sBaSS Robb SesSadabodsacncdcbodendccn 80 James collection oS JANSONIUS | (19GT)) eiceacecssctetceeneseecosees donne acy wueseeertaseer vente 44 JilSON (LOS U eestor ees tae esate aan cere ander tee seriecsocuec nates 27,85 JiISONTUGSS)eeecarese se ase eee ee rae aa eae enero eae 27,85 Juniatavhormationl ss2ccsse tse ecc sete eect ere eee ee eee 8 Kaljo (1956) Kaljo (1958) Kaljo (1960) Kealjo) (1961), ide sec ct cen vs ssnigvecessestucuse-s2 ass aaearcaeee sneateet Kaljo and Klaamann (1973) Kankakee Arch 112 BULLETIN 314 Kenophyllum Dybowski (1873) .........0ccc0eceeceecnecnecnecueseeees 76,77 subcylindricum Dybowski (1873) ...........000eeeeececeeneeeeeees 76,77 Kenophyllum? sp. Keemtu ck y) ots siect sees ies ie avec ni caves ovenstcwevoesGa-spasetesesscsen D505 : Burkesvillesmessecescscesroscore Fleming County Oldham County Wayne County KentuckyiGeolopicallSunveyier-cs---scresesce tases cease esese ae reeee 9 Keesling (1975) ) asa. Seek ssctucsacttccaeccenceseaessccerpecceacesss 6 Kobluksand@Riski(97/7) eeccs-cc.sscenesenenecerceccsnosnteecseasesseesens Kohutiand! Sweet (1968)\..-.c....cccsceseccscecessteosceocscree Kolata and Guensburg (1979) ..........ccceceeceeeee essence eeeeeeeueees 36 DA AK (S29) Asch soscesar ns ores eae tak nae cee meee ee tinamee store 35,36,80 Waker Michigan) 2: scccccccascsscssses scene csscersstccerscecesssessetsseaseis 30 Mamibex (901) mvt ores saceasesesace sets feane tec 59,60,62—64 6669-74 lamellosa, Grewingkia ..........00.c..cescevessscsecsecsrseccsecscoscceeses 77 Wanpeands smithy (1939) eecescrscceeeesecceeeeceneaseasserestereereneets 77,80 IEE TH 10)4 (17/5) eapondsaareeoocrecotoacreonecrcunenaseraamrerecsnrecriccasaccsscc 52 Tab) (1978) ection a oat oe sae oad ce de seachateasaeapeeusbaneeeenee 72 Daub (979) aise eeeoke cn ce cacee ac deanencvessnpseccses Sedan seco 52,82,83 Laurentian University collection ....................0cceeeeceeeeeee eee 85 Leemon Formation .................0000e0eeeeees 36,3839, 40,56,57,77,85 leemonense, Streptelasma ............0..06+ (eee 39,48,51,56,57,78 Beolasmauksaljo) (956) eeccecse-eesentesesecese cee seee se arene 61,64,77 (BepidocyGlusiGapaxerncsspecssecenseenseeeteaeeceee seers eee eee eater cet 23 ILA DGOEVADIS? QUATRE sencacoacacacanocececanceenecbananapebachoconceacns Shecesss Leptaena richmondenis ..........1..00:c0eceeccees nee eee ees eeneceeeeneenes 23 Wesperancel(968a) meee ee acsaetcenescceeaecse nese aeceeeese cca eeee 41,42 Tespérance(1968b)) oie .c.c.ce cess vsecesnssvecenensseovenscsnsscherssusedes 44 Wespérances(1974)) cs.cccceccscccsccsscwccovnaetnases vesetecdecescsebtens 38,42 Lespérance and Sheehan (1976) .............cceeeeeeeneeneee eens 38,42 Lespérance and Sheehan (1981) .............ccceceeeeee eee ece eee eeee es 42 WMesperancerefialai (98) rece seeseeeee eee see sees eeeee eee ene: 41,42,44 MibertyalOG4) Wetec ectee nh ecnctes saseecicecueacuhenchaee sacporeeareactees 66,69 Bibertiy(1969) wis .csetscceite cat eececenccaeacceecsuatesssincssteastiees ae 32-34 ibertyganduBoltoni(l97M) esses ce-eeeses-recnetdamseecoree seemetacesseacee 34 Liberty and Shelden (1968) ..............ccecceeeeeeeceeee eens 29,32,85 Liberty Formation 9 BindstrOm\(1882) ec. ainnscen cose soages svees cet osccseeneccaeanwauacaeaseeeee 52 Lindstromiasolearis) add) (1929) re sesesc ce sne see cence eoeteeeeee 80,81 Lobocorallium Nelson (1963)...............55- 18,48,49,65 ,66,74,75,76 trilobatum trilobatum (Whiteaves, 1895)............ 45,49,66,75,76 vaurealense (Twenhofel, 1928) ............ 13) ce 42,45 46,48, 49,66,75,76 trilobatum var. major Nelson (1963) 75 vaurealensis (Twenhofel, 1928)............2..2.....sceseveeeoess seen 75 Locality (see also Section) IETS Nae oe kcbenrethcaceterensr snes cca mesdersese seems a ames pae seme tere 32 BU npnbcheaboRE DRE pOCnN® HubO NE AOC hE Re aEOCEEacebaCnDnoooriganarabacceocee 39,56,77 QOD Past ie eee ceis Se Se wict ins teeta aes ce ea aa Dn eee 39,40 DIG) seidciesuic can sceasisusiiasseoovotovstedleevsoteocdaccheceesetencese Co eeomeeee 40 OO) TREE SAPP SCRE RPE ECAEEEEEE ORE EC ecn roca apa aaecaccocbanocaecc. 40 J BS 6} YOY. eenenodouEeoccoeaquaDAceconeracooORaTACONDODOSO TEL goo TaDCATaNanIEONOner 34 Magdefraui(1932)! .sc.2sc2ctecee2 ies isncccezenesecazecssc snore eeeseeorenee 17,18 Maine sei ss0 £62) aot acicaseees cee stesaneeeeeee 6,8,40,41 43 ,48,49,60,77 ‘Aroostook(G@ounty. <.:2:2c2i3s.d2-s0c-saeee scone tecets ono aeene eeetemaes 38 (Ashland ee re eerie ade enacsdteeene ec cteaet cee tenes 7,38 ,41,49,73 Penobscot County stis-ccese-c seen seceee ee re ne ee ee 7,41,49,58,72,77,78 Manitoba ............... 17-19,30,42,45,48,49,51,62,63,65,76,81-83 GE 1) | GREE aR RE Sean ae Bice ae ctaenasnceddnasbcenapoacisco0so000000C 61,82 Hudson Bay Lowland 64,82 Stony Mountain® (2 eso2escct-cscosceessctneeenossneeneeeee 65,74-76,82 manitobense, DeiracoralliuM ..........0c0ccccccccvenene ce eeeenenens 63-65 manitobense churchillense, Deiracorallium ..........0000000000+ 64,65 Maquoketa Group ....................- 8,12,28,29, 35,36, 38,40,41,44, 47,48 ,50,51,61,62,67,80,82 Maritimes: 50.4 s0c2) oyaccese scant Sevedbacsacueveseansecese te coset ee eee 48 Martin, "F-(I98O) i sccs sesee cite etecte cence see cececereseees 41 Martin, W. D. (1975) 11 Martin, W. D. (1977) 11 WY ETAT eC TE, (COTS) ceo coscensoumacesanceanoaaccnonanagasooncnnsnosonopoasnccens 42 Maxwell (1936) 38,39,51 McCracken and Barnes (1981) ................0seeee eee 36,38,41,42,45 McGCrackenlerial. (1980)inserasccneccescencece cose erenescceseeeeatemecece 36,38 Ro BETTIE) eBeraronaconeargonstonocnacnocenpanSoancdaponssa6en0c0 52,65,77 14 (eo) UCT 0 (1/70 eaataeeeeeeercaceRecterrecarcospaoedaomoaasboncenaasaconen. 76,77 Meadowvale Memben: ..o253.c.-.c0c0teeeecs ee scse asec eeereeeae tenants 34 Meeki(1 865)! siicceecstsecseodsctinsteeneen cess eccinccieeis 35,64,66,75,76 Mesler’ collection ....2:2:0.ccv.0. s.teaccscsseseecocesecuetseetecesensneennae 67 Michigan «..2.........sccisiectaeessccsssssecneseovsce touche eee De Os Osea amo Issue thy GLE INIOYS.ocncoagnacnaassagsaanconpendaonnnadEnSnossoncancnscooss 29 Deltav County sere. t.. eeeec ceo cea eee oo oot 53 ,56,69,70 Drummond Island ............... 6,7,14, 19, 30-32, 33,50,66—-69,85 Little Bay de Noc 6,7 29,30, 50,85 Stoningtomiseccsescecreces cee c sees see ee eeeten cies see cee snetaeeteereaeet 54 IY TVS TEE) BGT gsoscedcacoccnodesneasosoerneaaoousrcoadeacopScnsonaiconsaacans 12 Milne-Edwards and Haime (1850).,................020ceceeeenee snes sees $2 Milne-Edwards and Haime (1851)..................0c0ceeceeeeeeee eee 66,69 Minnesota’: .3.0.00cssceo ee ce eee ... 35,50,56 Mississippiivalley eessceeeecertec sea eeee cee tce ten ce sete sees eeeteste eet 48 MiSSOUMI.. 2. 5.oc0c--nsececteroeess Js Toys thita( G22) 1 conconqdapandseonorcosecancqanoanccaadooqandssconcecosnaoses Cape Girardeau County (CHRSINS. SpsauoccencacancdeobscnsocanaEancenanoo coon dqneDobodCuCHOCONODOCNOT 1 Bahe7=\', 70780) anaguaqaososocespacsanaacaccosccdeccscanoaadnoodcdon9aD0NIGG0S JLECINVOSNY GripsngobbdocsoooosecuaccusosenoseondnncacooocosansanngonosGnoonscans PiketCounty eeeeeete eee eee eee eee eee eee Mormon! Greek) Formationiose-ese: eeee eee ee eee epee nee 29.30 Murray collectiontess-ceseseecresscses seen creccen cern sens tieekieestesteente rats 66 Nashville’ Dome? < corde sarc gactadhe nace wed Staaee sweetest ads oa Meeeseoawesbemeesee 70,72 ESMOND, SUAGOGTEN AG! conccasnsecacoocousenecDs05002 27,34,50,66,69-7 1 rusticum Var. trilobatum, Streptelasma ........0..00000e0ec0e0eees 74,75 Rey d erg (W926) esecccn cas accc a coe acesesanacacsoceceine sees ace se sone nae Tl Satterfield (1971) Savage collection Savages(L905) geceae ats. sae sedeaens sencoseeacaecweanc eves asentuhcaete ee eeananer Savacer (L908) ras. 05. corencuntatacniewscaresoniseceescco-eeoreieenenc oder aaane SEN ETS: CIID Fg ecpane coast encccnacanosesnaacddanbancenuanangresenanscsaocs Savage (O13) | vresccesescscssecdccciaetrescenes 38-40,45,48,51,57,58,60 SENET 3 | CICHIT EN Saree Saronanebcepacctraaccee emecunbercceosocconcses 36,40,57 Savage (QD) iisccccconcnscsteear nese ve oeoaaesenrtieseeaclons Capeceemne wean 36 Savace (925) is tees ccdecte cess cseeceacavsinws ve aesioesncesloes steebane ote cueae 36 SavaveandiRossy (L916) cesecc se sessassn-sose ss ssc svese e _¢ z 2) 194-2 A Z = 1OWA = = = IA ey hae et | ees Bey) |e | ee One To ees ° ae pe Mere | i. z 198-1 ! = = ise = Wel qe < a i -3 e = Eee 3 OF Se As aaa ae cs 2 x2 ! ° te) s } 9 cs) BS one e =I 3 oy is ILLINOIS ' = 7 3 a 5 ' > —— va-1{ E st = c 1 3 2 1 —— Way 5 ox ’ oe 1 ag ' om 2 18. DRUMMOND |S & ' eon 17 LITTLE BAY DE NOC 19 MANITOULIN IS i x 2 w ° — = e a re a —— 2200 z w ° w A 3 > 5 °o 3 é : : 5| > | 3 > 3 é a = a « 2 : 6 z oi = = > 2 gE 3 ° 3 5 ar — i : : E 2s s H ra i —— E : a 3 uw @ BRAINARD = eal = Ei 8 : a ee i) 7 ae 3 2 CFORMATION 5 © 50) = 1 3 2 ecg es | z —— = I Ee) Tuli rae es <= G i i ae ea g 3 =e : ees al z EDENIAN- 3 3 Om! u Fe == MAYSVILLIAN < 4G Elgin MI <= STAGES = | 24 -——4 2 Om: ci 3 GI 2 | tc! ———_ DRUMMOND IS. & SS MONTREAL LAKE ST. JOHN THEBES NE IOWA SE IOWA & NW ILLINOIS LITTLE STURGEON BAY LITTLE BAY DE NOC MANITOULIN Is MEAFORD STREETSVILLE PREPARATION OF MANUSCRIPTS Bulletins of American Paleontology currently comprises two or more sep- arate monographs in two volumes each year. This series is a publication outlet for significant longer paleontological monographs for which high quality photographic illustrations and the large quarto format are a requisite. Manuscripts submitted for publication in this monograph series must be typewritten, and double-spaced throughout (including direct quotations and references). All manuscripts should contain a table of contents, lists of text-figures and (or) tables, and a short, informative abstract that includes names of all new taxa. Format should follow that of recent numbers in the series. All measurements must be stated in the metric system, alone or in addition to the English system equivalent. The maximum dimensions for photo- graphic plates are 178 mm x 229 mm (7” x 9”; outlined on this page). Single- page text-figures should be drafted for reproduction as single column (82 mm; 34") or full page (178 mm; 7”) width, but arrangements can be made to publish text-figures that must be larger. Any lettering in illustrations should follow the recommendations of Collinson (1962). Authors must provide three (3) copies of the text and accompanying illustrative material. 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Explana- tions of text-figures should be interleaved on separate numbered pages within the text, and the approximate position of the text-figure in the text should be indicated. Explanations of plates follow the Bibliography. Authors are requested to enclose $10 with each manuscript submitted, to cover costs of postage during the review process. Collinson, J. 1962. Size of lettering for text-figures. Journal of Paleontology, vol. 36, p. 1402. Gilbert Dennison Harris (1864 - 1952) Founder of the Bulletins of American Paleontology (1895) ops dnoud GNOWHOIY aio 282 g = 3 o SU se ‘NHOHY13 (STIIASANAWM, | WISHNYY! eu o - Y3AVMALIHM - ALY3BIT. ox = ERS eS — ° ES see ssuepeues 5 — el ten ao: 2 aly (hon Bes 1 AEA , a26 | |9 " cy ne i Zy3s Dawe CIN a7 “aa eqnsseuseeid yeas fee3] aN PuEIMoN / Seu NolLvWHOS Sayvud W4 XOOTHSY me eZ = aoe eee ee oe =e pees aes 3 i g 3 Eos = =) 242 « © Sas aoe < : eee Qa a © oO Sut nh ou cc a2 Kut 3s NWA at Hit yea! =e ron Hu nu an - SK ts i puejmoy = z = NOILVWHOS saynvud ae ape =e fia 530 < a= —_— . —- +» -<—— ° <0 rae w= an eke SURE S = a= sjsuepeues ‘5 oto = HT = L — ZO 9 eUG aN IGN sc = PueIMoY Zeqay /i124 we SS W4 OOTHSY ess ee = —e25 Baas sao Sere ar geg (a4 = = | = = iat = aus ° one Oe aae “Fauepeues 5 — eae & Ey Tf 25 in ae nit i 7 tate} By BT @Asseyoeras, aN. Mills oh Fo 3 a IIIASSO4DEOId on 25 NOILVWHOS sayvua SOOTHSY 3 = ‘oe o —- 2 4 won oi|AsueYyoeedg nu 3 NOILWWHO4 yHOs 3 a 8 3 3 ee i ————— ° - suesuenp Ss - S)suepeues ‘5 - SueoneAIp " sisuepeues wy tart 4 138-1) WNNHYOHW13, MILVMALIHM, eee dnousd ovogss ida ee ee ¢ 8 & 2 é \ATTIASANAYM, WISHNYEW GQNOWHOI& 14. Ft. Ancient-Cowan L. 1. Maysville West Union 10. Hillsboro 9. Agawam 7. Union City 8. Richmond, KY 6. Preachersville Dayton 13, [49 GNOWHOKY| Freel os 3 a gee) z3 > Fear zo Exo) ew Esai a> if = t { Gallatin Sisuspeues 5 =| 2 2 z * & a = ? x 2 nt » w t : ° et a \ & > 2 z e = 7 =) ares 3 3 = [=p 5 = = 4 eel ° ' ST Aimee = ee oS tee ve eons SF oer °o o = Yo © fe) Gres = WW Saey “ee z fi als fe] ) § 3 -o-—-wo eee ° 8 oe: me ' MES esoBny Aseyjos - & . i | ° of 58 o 238 e 2 2 see 6 E o o Ao ees o@2o $3 Sue ese an oe £88 a5 3 o> <0-—u>+— v—>~ . rd re Zee ge egssee Sade Sueanenlp ‘S = 25 Sar 22 ss sy rel|) Basses Over Ss 28s 5.5 8 5 2 5 = (ie eee wess ce ELS BSS FF SSS Na Ga RA : Nit H i iit i i th lena qo) 4: it adnan Taw 4g) Gpnies. [umorspieg| 24W PUEIMoH NOlivWwuOod sayvud 5 99F 9 tere ¢ ees Py cr) = > -< % = ° ~ esoBny Auejos oa SueoTAeAIp “S == sisuepeues ‘5 a i uN QW led epnies|aqw shut QW pueIMoH NOILVWHOS sayxvud aNOLS3WIT) = aT INWHS 7 OS oO ° o 7 - ° -0-< ao e = esoBny Aseios sueouenp *S§ —-— Ssuepeues “ ———= Se etc = Li! i titi | YQW eNWOo}Og epnies 4qW umojspieg NOlLVWHOS saxvud ‘W4 yyOd 77N8 2 ——9——— o> eS ° = Seg Suesuenp S — Sisuapeues ‘5 ——s ie W4 YaLWMaLIHM wa ovogsiid SSS ee ge ae = 3 2 2 8 weer < 3 ere rn = Sueo|eA|p 'S == — — S)suapeues ‘5 = Th CUT NOILVWHOS ovogsiia we oFs ee a pe ee fe a ae Pr ryeh ey rel ra oer eee 3g 8 Hy esec c as See 532.2 Boer - —— - ——_> c 35 ° ° ° ° SUuewres ie: Wmectesie alsiraaie es ---- —$_ — = ~——Ci=- ------ Sie fe) ieee Ceeesien fi bm cops ey Se eee ee Pace S18 (8 (SeUeS SoS side rr ee ee ' on ail tH | esoBny Aieyyos sjissopebow mt a il a litt HTH HHA Ht 2 Apmis siyy ul persesqo asnjesayi| uy paysodes se HAH eee 4 9° fe] E NOlLVWHOS H3LVMaLIHM |'W4 O808STIIC S o & 2 . 6 ——s ee es = = = eee Siro “ON U01}9a//09 2 "ON Ayeao} 2 5 o 7 me J = 2 a a a e ae Ayier0} 3 x 2 7 ss £ A = L 8 2 3 iS] sNYOHW 13. }HALVMALIHM, ALY3ASI1 ATTIASANAYM, | (WISHNYY. dno SD QqdNOWHDOI 16. Goodlettsville 11. Versailles 2. Bedford 3. Seatonville 4. Fredericktown 15. Burkesville 5, Brookville 12. Richmond, IN it tn draye date eee Shoko Dit me ow, i EES A Rt ore enw e sine PR Sere Sik Sa caieengerans eid ra ¥ i WET te Fase pe pie anes re Oe enh he OES Serer Lg Op Seay Sethe PAM fe ih ad aad © Oe Renee pitti ere ne : IP Het ve sy Pera ety jah ed eg eae FEO eae Saas Cee nates Pas — pee Nor VM Awan Owain Py 5 Leavis Wee en; Ment uve Rea Ty aves hints } aN ert UV en's Pa petaire Sagres Corre ean an ek RROcn rn we sasha ys DURE Crane : wean ers BAS fg, Aveta cae Ors a ‘ ‘ intr nee PI Sal Ode Outs PAO hat ' A at ALS ¥ titty .