BAYLOR Bulletin No. 39 A Study of the Crinoid Genus in the Hunton Group of Pontotoc County, Oklahoma BRADLEY S. RAY Studies EDITORIAL STAFF Jean M. Spencer Jenness, M.S., Editor environmental and medical geology O. T. Ph.D., Advisor, Cartographic Editor what have you Peter M. Allen, Ph.D. urban and environmental geology, hydrology Harold H. Beaver, Ph.D. stratigraphy, petroleum geology Robert G. Font, Ph.D. engineering geology, geomechanics, tectonophysics Robert C. Grayson, Ph.D. stratigraphy, conodont biostratigraphy and sedimentary petrology Don M. Greene, Ph.D. physical geography, earth sciences Don F. Parker, Ph.D. igneous geology, volcanology, mineralogy, petrology STUDENT EDITORIAL STAFF Diane Mueck, Cartographer The Baylor Geological Studies Bulletin is Spring and Fall, by the Department of Geology at Baylor University. The Bulletin is specifically dedicated to the dissemination of geologic knowledge for the benefit of the people of Texas. The publication is designed to present the results of both pure and research which will ultimately be important in the eco­ nomic and cultural growth of the State. ISSN 0005-7266 Additional copies of this bulletin can be obtained from the Department of Geology, Baylor University, Waco, Texas 76798. $1.05 postpaid. BAYLOR GEOLOGICAL STUDIES BULLETIN NO. 39 A Study of the Crinoid Genus Camarocrinus in the Hunton Group of Pontotoc County, Oklahoma Bradley S. Ray BAYLOR UNIVERSITY Department of Geology Waco, Texas Fall, 1980 CONTENTS Pag Abstract Introduction Purpose Location Procedure Previous works Acknowledgements Description History of Discovery Association with Scyphocrinites Occurrence in the Rocks Discussion of Probable Functions Conclusion References ILLUSTRATIONS FIGURE 1. Location map of study area 2. Map showing collecting localities 3. Characteristic speciman of Camarocrinus 6 4. Cross section of a bulb and detailed section of wall structure 7 5. Diagrammatic section showing wall structure 7 6. section of Camarocrinus showing relationship of stem and various wall structures 7 7. Floorlike layer of plates which roots rest upon 7 8. Top view of bulb showing channel openings 8 9. Side view of base of Camarocrinus showing stalk wedged into roots 10. Collar of Camarocrinus with plates removed to show perforations for nerve cords 8 Cross section of bulb showing location of chamber 8 Scyphocrinus and Camarocrinus associated on the same bed of limestone Transverse sections through the stalks of Scyphocrinus and Camarocrinus Stem characteristics of Scyphocrinus 10 Location 1. Colony of bulbs found in the Haragan Formation Location 2. Group of bulbs showing upward orientation of stems Location 3. Stem orientation of bulbs 12 18. Limestone slab showing position of bulb in 12 19. Roots of young crinoids attached to Camarocrinus 13 20. Young crinoid roots attached to mature bulbs 13 21. Geopetal structure showing downward orientation of the stem of Camarocrinus 14 22. Geopetal structures indicating a sideways orientation 14 23. Geopetal structures indicating the preferred orientation the holdfast 14 24. Geopetal diagram representing the stem orientation of the holdfast Camarocrinus 14 25. Stem orientation (upward) as found in outcrops of the Hunton Group in Oklahoma 14 26. Schematic reconstruction of Camarocrinus A Study of the Crinoid Genus in the Hunton Group of Pontotoc County, Oklahoma Bradley S. Ray ABSTRACT The crinoid genus Camarocrinus has been described as accepted as fact until evidence is found to conclusively an independent class of echinoderms, cystoids, genital support such a hypothesis. sacs, brood-pouches, pathologic cysts, anchoring roots, As opposed to the "float theory," suggested in most of and as the floating organ of the genus Scyphocrinus. the current literature, the conclusion of this study offers It has been commonly accepted that Camarocrinus support to the more natural interpretation that Camaro­ was connected at the distal end of its stem to the stem of crinus, an independent crinoid genus, served as enlarged Scyphocrinus. This study shows that the assignment of roots, anchoring an unknown crinoid to the substrate. the bulb to the second genus should not be so readily PURPOSE PROCEDURE This study was initiated to review, clarify, and expand order to clarify the existing knowledge of Camaro­ our understanding of the crinoid genus Camarocrinus crinus, a thorough literature review was done and various and to offer scientific evidence regarding the function of paleontologists who have studied echinoderms were con­ the bulb and the crinoid's mode of life. sulted. Field work was restricted to the occurrences of the crinoids in the Hunton Group of south-central Okla­ homa. Field and laboratory work included the collection LOCATION and examination of over 400 bulbs. The area of study is located in southeastern Pontotoc Two-hundred bulbs, selected as representative fossils County, Oklahoma, along the northern edge of the from the outcrops, were sectioned, using a rock saw, and Arbuckle Mountains (Fig. 1). Three localities were the geopetal structure revealed in each bulb was recorded. selected from the known occurrences of the bulbs, and The position of the bulbs as they occur in the outcrops from these, specimens were collected for use in the study. was also documented. The morphology of the fossil was Camarocrinus is found in the Haragan and Henryhouse studied in detail, enhanced greatly by the use of to Formations of the Hunton Group exposed at the locali­ clean the bulbs and a microscope to examine their intri­ ties in southern Oklahoma (Fig. 2). cate structures. PREVIOUS WORKS thesis submitted in partial fulfillment of the B.S. degree in Geol­ Many authors have included in their topics of discus­ ogy, Baylor University, 1980. sion various theories regarding the function of the BAYLOR GEOLOGICAL STUDIES bous growths known as Camarocrinus. These studies include such works as: "Notice of Some Remarkable Crinoidal Forms from the Lower Helderberg Group," Hall "Systeme Silurien du Centre de la Boheme," Barrande (1887); "Die Amphorideen and Cystoideen," Haeckel (1896); "Uber Sogenannte Jaekel (1904); "On Siluric and Devonic Cystidea and Camaro­ crinus," Schuchert (1904); "O Nakhodke Lobolitov v SSSR i o Biologicheskom Znachenii ikh," Yakovlev and "O Taksonomicheskikh Priznakakh Segmen- tirovannykh Stebley Morskikh (1967). The two most thorough works done to date are: "On the Genus Scyphocrinus and its bulbous root, Camarocrinus," Springer and "Ban and Funktion de Scyphocrinites-Lobolithens," Haude (1972). Springer is credited with having proven the association of Cama­ rocrinus with Scyphocrinus, and Haude is referred to as having scientifically proven the theorized function of the bulb known as the "float theory." This study examines these and other works and the theories they present, and objectively examines the evidences used to support the Fig. Location map of study area: Southeastern Pontotoc County, theories. Oklahoma. ACKNOWLEDGEMENTS The writer thanks Dr. Gustavo A. Morales for his help, guidance, and encouragement, and Dr. Robert Grayson for the suggestion to use geopetal structures to aid in reconstructing the mode of life of Camarocrinus. Special thanks are extended to Bunker Hunt for access to his ranch, the area of study, and to my grandfather, Pat Ray, Sr., who has collected several thousand bulbs from various localitites and first introduced me to this unique fossil. Also, the writer would like to thank Bette Winter for translating Haude's study from German to English, and Muriel Mason for typing the final draft. Fig. 2. Map showing collecting localities in the Hunton Group, Pon­ Fig. 3. Characteristic specimen of Camarocrinus. After Schuchert totoc County, Oklahoma (Hardin City Quadrangle). 1904, CAMAROCRINUS IN THE HUNTON GROUP 7 DESCRIPTION is a hollow, rigid, chambered body with branches into the system of roots, forming a neurovascu- a short collarlike projection encompassing a bilateral- network that is spread throughout every plate in the symmetrical stem base of bifurcating cirri (Fig. 3). It has bulb (Figs. 9 and 10). several internal saclike structures, which open to the Below, unpenetrated by the axial canal, lies the me- exterior through large, single, channellike openings. The diobasal chamber, surrounded by three to as many as openings are located in the axis of each main root chambers. The chamber is the space at the bifurcation. center of the bulb between the chamber walls (Fig. The walls of the bulb consist of three calcareous layers. These layers are derived from the root system by repeated divisions of the main cirri. The plated cover layers (Figs. 4 and 5) are formed from thickened portions of the irregu­ lar cirri that form the middle The main cirri rest upon a flattened layer of plates originating in and formed from the lateral rootlets (Fig. 7). Some of the cirri turn upward from the tloorlike layer, to form the single-layered collar (Fig. Others project downward to form the walls of the chambers. Each of the main cirrus bifurcations contains an open­ ing leading into one of the chambers (Figs. 7 and 8). There are as many chambers and related openings as there are main cirri. The crinoidal stem rests on the primary root member as shown in Figure 9. Where the stem wedges into the primary root member (Fig. 9), the stem's axial canal Fig. 6. Generalized section of Camarocrinus showing the relationship of the stem and various wall structures. After Springer, 1917, p. 17. Fig. 4. (4a) Cross section of a bulb and (4b) detailed section of wall structure. After Haude, 1972, p. 109. Fig. 7. Floorlike layer of plates which roots rest upon; broken lines Fig. 5. Diagrammatic section showing wall structure. After Moore, indicate interior canals; also shown are the chamber openings. After 95. Schuchert, 1904, p. 264. 8 BAYLOR GEOLOGICAL STUDIES Fig. Cross section of bulb showing location of chamber (M). (x 0.5) Fig. 8. Top view of a bulb from the Hunton Group showing channel (x 0.7) Table 1. Systematic Paleontology Camarocrinus. - Phylum - ECHINODERMATA Class - Miller Subclass - Springer Order - Moore and Laudon Family - Bassler 1833 elegans Zenker, 1833; Scyphocrinus Roemer, 1855; Barrande, 1868; Camarocrinus 1879.