PALAEONTOGRAPHICA AMERICANA (Founded 1917) VOL. VII Library of Congress Card Number: 73-163637 Printed in the United States of America Arnold Printing Corporation CONTENTS Page Abstract 161 Introduction 161 Acknowledgments 161 Geographic and stratigraphic considerations 162 The rudist shell 163 Shell structure 164 Definitions 16+ Classification 165 Systematic descriptions 166 Monopleuridae - - 166 Caprotinidae 168 Caprinidae 168 Caprininae 169 Plagioptychinae 179 Radiolitidae 183 Radiolitinae with ligament 184 Radiolitinae without ligament 186 Sauvagesiinae with ligament 196 Sauvagesiinae without ligament 198 Hippuritidae 203 Hippuritinae 203 Barrettiinae 207 Bands, pillars, and oscules 217 Stratigraphic distribution 220 References 221 Plates 223 Index 256 TEXT-FIGURES Page 1. Sphaerucaprina scafieldensis (left valve, commissural aspect) 170 2. Antillocaprina occidentalis (left valve, commissural aspect) . 173 3. Antillocaprina loivcnstami (right valve, section) 174 4. Agriopleura falconi (right valve, section) 184 5. Praeradiolites verseyi (reconstruction of right valve) 185 6. Orbignya ceibarum (section showing hinge) 205 7. Barrettia monilifcra (longitudinal section, after Woodward) .. 209 8. Barrettia multilirata (structure of left valve) 212 9. Barrettia multilirata (section below commissure) 213 10. Barrettia multilirata (section at a lower level) 213 RUDISTS OF JAMAICA L. J. Chubb ABSTRACT the Jamaican rudists have long been out of print and are All species of rudists known to occur in Jamaica are described today almost unobtainable, and many of their descriptions and figured. Of the 71 species, 37 were already known; these are are inadequate or inaccurate. time seems ripe, there- re-described on the basis of a re-examination of the original material The and, in most cases, of new material. Of the remainder, five forms are fore, for a new monograph in which every known Jamaican new to Jamaica but are referred to species which occur elsewhere; species of rudist, both old and new, will be described and another five which are imperfectly preserved are described as far as possible; they are unnamed, but three of them are compared with figured, and placed in its correct stratigraphic and taxonomic known species. The remaining 24 species, which include one new context. genus and eight other genera new to Jamaica, have been briefly described elsewhere and are here fully described and figured for the ACKNOWLEDGMENTS first time. This work is based upon 14 years study of Jamaican INTRODUCTION Cretaceous palaeontology and stratigraphy carried out while Rudists, though not the commonest, are the most the author was a member of the island's Geological Survey. characteristic fossils of the Jamaican Cretaceous rocks. Many of the specimens here described were collected by The group receives scant treatment in most text books with past and present members of the Department, whose help the result that many students, even professional palaeontolo- and cooperation is gratefully acknowledged. Much of the gists, have little basic knowledge of it. In early days there writing was done between September, 1963, and June, were differences of opinion as to their systematic position, 1964, at the University of the West Indies, Mona, and it was various species having been assigned to the Brachiopoda, continued in England chiefly in the British Museum (Natu- Cephalopoda, Cirripedia, and Coelenterata but, since the ral History). My gratitude is due to these institutions for beginning of this century, it has been generally recognised the facilities they afforded me and especially for allowing that they were highly aberrant bivalved mollusks, i.e. me access to their collections. The Trechmann Bequest was Pelecypoda or Lamellibranchiata. received by the British Museum (Nat. Hist.) while I was Lucas Barrett (1860) first recorded the presence of working there; it included several new species and many "Rudistes" in the island. Since then Jamaican rudists have specimens of known species in a better state of preservation been described by Woodward (1862), Whitfield (1897a and than any previously seen. b), Trechmann (1922, 1924b, 1927, 1929), and Chubb I am indebted to the American Museum of Natural (1955a, 1956a and b, 1967). The descriptions are scattered History for certain photographs, for the loan of several type through several periodicals and the collections also are specimens, and for permission to reproduce a number of scattered, Woodward's and Trechmann's types being in the illustrations from Whitfield's articles in their Bulletin; to British Museum (Natural History), Whitfield's in the Dr. H. G. Kugler and the Naturhistorisches Museum, Basle, American Museum of Natural History, and Chubb's for- for the loan of their collections; and to Professor M. G. merly in the museums of the Geological Survey of Jamaica Rutten of Utrecht University for the loan of certain Cuban and the Department of Geology of the University of the specimens. Some of the figures have previously appeared in West Indies, Kingston, have been transferred to the Smith- Palaeontographica Americana, volume IV, numbers 26, 27. sonian Institution, Washington, D.C. There is a collection in Thanks are due to the editors of the Geological Magazine the Museum of the Institute of Jamaica, Kingston; one for permission to reproduce one of Woodward's figures in made by G. P. Wall in the British Museum (Nat. Hist.), the Geologist for 1862 and to the Societe geologique de London, which has also acquired the Trechmann Bequest, France for permission to reproduce a figure from Douville's including some hundreds of Jamaican rudists; a collection Revision des principales esfeces d'hippurites. The majority made by C. A. Matley is in the United States National Mu- of the photographs are new, some having been made by seum, Washington, D.C, and one made by P. W. Jarvis is Dr. Tom Goreau, others by Mr. Owen Jackson, both of in the Naturhistorisches Museum, Basle, Switzerland. All the University of the West Indies, and many by Mr. A. these collections have been studied by the writer. Rowe of the British Museum (Natural History). In recent years several previously unknown rudisti- Finally I gratefully acknowledge my debt to the late ferous horizons have been discovered and a number of new Dr. L. R. Cox for help and advice while I was working at species or species new to Jamaica have come to light. New the British Museum, (Nat. Hist.) and to the late Dr. C. T. work on the stratigraphy and palaeontology of the Cre- Trechmann who first introduced me to the study of Jamaican taceous has made possible a more accurate zonal sub- rudists and whose criticisms kept me on the alert and com- division and correlation with the standard succession than pelled me to confirm every observation and reconsider could previously be attempted. The older publications on every conclusion during my work in Jamaica. 162 Palaeontographica Americana (VII, 45) GEOGRAPHIC AND STRATIGRAPHIC late exactly the rocks in one inlier with those in another, CONSIDERATIONS so there may be gaps or overlaps. Twelve limestones are included in the table and every one of them yields rudists. The rudists originated late in the Jurassic Period, but The dating of the various series has been done mainly on were especially characteristic of the Cretaceous, reaching the basis of their microfossils, except for the Lower Cre- their acme in numbers and variety in Upper Cretaceous taceous up to and including the Albian, in which only times, and becoming extinct at the end of that period. Their macrofossils have been found. distribution was determined partly by geographic and partly The rocks of the Benbow Inlier of northeastern St. by climatic factors. Their zone of maximum concentration Catherine are slightly metamorphosed, with the result that coincides closely with that of the Tethys; they were essen- the rudists are welded into the limestones and can be tially benthonic animals, able to live only in fairly clear studied only on weathered surfaces or in sections. It is water in the shallower parts of the geosyncline and in the now known that the Bonnett Limestone and Copper Lime- seas connected with it. They could develop a full and stone, previously regarded as distinct, are one and the abundant life only in the tropical seas of their time. same. The Phillipsburg Limestone, formerly thought to be The rudist belt of maximum concentration runs from equivalent to the Copper, is now believed to be a local southern Mexico through the Greater Antilles; it is con- lenticle at a slightly lower horizon. A fauna similar to that tinued northeastwards in Portugal and the Pyrenees, thence of the Seafield Limestone has been found in rocks of Lower eastwards across south Europe and Turkey and southeast- and Middle Albian age in Texas, and the fauna of the lower wards through Iraq and Persia, beyond which it passes into limestones suggests a still earlier age. It is only in this the Indian Ocean. According to Douville (1900b, p. 235) the middle line of the belt departs little from a circle which would cross the equator at an angle precisely equal to the TABLE 1 inclination of the ecliptic. Northwards and southwards of Cretaceous Succession in Jamaica the belt rudists become scarcer and eventually disappear, their northern limit extending beyond 50°N in south Sas- katchewan, southern England and Sweden, Esthonia and Moscow, to little more than 30°N in Tibet and to 17°N in the west Pacific. Their southern limit extends to 30°S in Chile, though elsewhere in the continental areas it does not reach as far south as the present equator, embracing only northwestern South America as far east as Trinidad and the coastal belt of north and northeast Africa. Only in the area of the Indian Ocean are rudists found again in the Southern Hemisphere. No Jurassic rocks are known in Jamaica. The greater part of the island consists of Tertiary and Quarternary for- mations but the Cretaceous appears in many inliers, the largest being the Blue Mountains with an area of about 240 square miles, and the smallest occupying only a few acres.