Durham E-Theses The devonian goniatites of Devon and Cornwall House, M. R. How to cite: House, M. R. (1958) The devonian goniatites of Devon and Cornwall, Durham theses, Durham University. Available at Durham E-Theses Online: http://etheses.dur.ac.uk/9179/ Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in Durham E-Theses • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full Durham E-Theses policy for further details. Academic Support Oce, Durham University, University Oce, Old Elvet, Durham DH1 3HP e-mail: [email protected] Tel: +44 0191 334 6107 http://etheses.dur.ac.uk frontispiece THE DBVONIAF GONIATITES OP DEVOU AED CORNWALL By M.R-. HOUSE M.A. Thesis submitted for tlie degree of Doctor of Philosphy in the University of Durham, 1958 11 ABSTRACT A description of the Devonian goniatites and their localities in Devon and Cornwall is given based upon museum material and new collect• ing. This enables correlation with the established continental success• ions and the following German ammonoid faunas have been recognized : LO?/ER CARBONIFEROUS Gattendorfia X Wocklumeria X UPPER Clymenia X PAMENNIAN Platyclymenia X DEVONIAN Cheiloceras - PRASNIAN Manticoceras X Maenioceras X MIDDLE . DEVONIAN Anarcestes X LOWER DEVONIAN Mimosphinctes - The fauna of the Anarcestes Stufe has been recognized in South Devon and probably in Cornwall. Two faunal subdivisions of the Maenioceras Stufe have been recognized, the lowest only at Wolborough, South Devon, the uppennost at Lummaton and Barton, Devon and Trevone and Portq.uin, North Cornwall (the last two localities have previously been identified with the Cheiloceras Stufe). The three German zones of the Erasnian have been identified in South Devon but only the middle one with certainty • in North Cornwall. The Eamennian ammonoids have not been exhaustively examined. Only Maenioceras Stufe goniatites occur in the massive lime• stones of South Devon which appear to be wholly Givetian in age ; no Prasnian goniatites occur within them but they are fOTind in the thin- bedded or rubbly limestones immediately above. The absence of evidence for the Cheiloceras Stufe emphasises the widespread development of ostracod-slate facies at that time. The recognition of the Gattendorfia and Wocklumeria Stufen (largely the work of others) tells against the large unconformity usually supposed to mark the base of the Carboniferous in South-West England. Ontogenetical details are given for several species : the evidence from Maenioceras shows that it probably evolved direct from Anarcestes or early Wemeroceras. Peculiar internal growths on specimens of Sobolewia shed light on the relation of the soft parts to the shell in goniatites. iii OOHTMTS Page PROmSPIECE TITLE PAGE i ABSTRACT ii COITTEHTS iii PREFACE AITD ACKNOWLEDGEMENTS iv Chapter 1. INTROLUCTION (with a note on abbreviations) 1 Chapter 2. THE CONTINENTAL DEVONIAN AMMONOID ZONES 4 Chapter 3. THE DEVONIAN GONIATITE LOCALITIES IN DEVON AND CORNWALL 16 Chapter 4. SYSTEMATIC PALAEONTOLOGY (with a separate list of contents) 54 Chapter 5. SUMMARY OE ZONAL, STRATI GRAPHICAL AND PALABOGEOGRAPHICAL CONCLUSIONS 199 REFERENCES 204 PLATES (1 to 23) Appendix 1. AN INDEX OF DEVONIAN GONIATITE GENERA 220 Appendix 2, AN INDEX OF DEVONIAN GONIATITE SPECIES 231 iv PREFACE AND ACKITOWLEDGELIENTS The Devonian goniatites of Devon and Cornwall have received little attention by comparison with their continental equivalents. The important conclusion of this work is to show how useful they are for stratigraphical purposes. This thesis attempts to review existing material and is an interim report upon work and collecting still in progress. A little under half the material described, much from new localities, has been collected during field work in the period 1954-1958, the period of this research. The Pamennian clymenids have not been studied since, in 1955, Mr. E.B:. Selwood commenced research on the South Petherwin area, the richest region for English clymenids. The conclusions here found relate mainly to the Couvinian, Givetian and Prasnian and the Pamennian goniatites have not been exhamined exhaustively. The work has been under the supervision of Professor K.C. Dunham P.R.S., to whom the author expresses his thanks. The following gentlemen have kindly assisted in the collection of material or have loaned specimens for study : L.G. Anniss, G.P. Barter, N. Butcher, W. Dearman, D. Dineley, K. Joysey, D. McKie, the late P.J. Oliver, A. Pedder and J.E. Prentice. Thanks are due to the curators of the museums mentioned on page three and several continental museums for allowing access to the material under their charge and, in several cases, for allowing it to be loaned for study. Dr. W.H.C. Ramsbottom of the Geological Survey and Dr. M.K. Howarth of the British Museum have been most helpful in this respect. Others have contri• buted in answering queries on various matters, especially the late Dr. W, J, Arkell, Mr. W.S. Bisat, Dr. P. Hodson, Mdm. G. Petter, Mr. R. Phillips, Dr. H. Sdbnmidt and Dr. H.B. Stenzel. The Durham Colleges'- Research Pund have given financial assistance towards the cost of field and museum work in England,, Prance, Belgium and Germany, and an award of the Daniel Pidg- eon Pund of the Geological Society of London has helped work in North Cornwall. The Harkness Scholarship from Cambridge University has consid• erably aided the accumulation of a library of works on the Ammonoidea. A great debt must be expressed to Mr. G. IcKenzie of the Durham Colleges' Science Library and his assistants for obtaining many works of reference. Mr. C. Chaplin, Mrs. J. Harker and Mr. M.S. Maconochie of the Durham Colleges' technical staff have given considerable help in the preparation of text figures and plates. The majority of photographs which accompany this thesis were taken by the author but they were all printed by Mr. Chaplin or Mr. Maconochie who also took several of the photographs appearing on the later plates. Chapter 1 INTRODUCTION Because of the thrust and contorted nature of the Devonian rocks of South-west England, and the relative paucity of well preserved fossils, exact determination of the succession in most areas is very difficult. In these circumstances any fossil which can be used to give an age determination becomes important, and each new determination becomes a step towards the elucidation of the many outstanding stratigraphical and palaeontological problems. In Germany, ammonoids excel all other fossils in their usefulness for correlating the Devonian. This study has been largely an attempt to see if goniatites in particular could be used to more advantage in dating the English Devonian rocks in which they occur. Although they have never been the object of systematic study, numerous geologists and palaeontologists have described or recorded goniatites and clymenids in Devon and Cornwall, The first locality to attract attention was the Upper Famennian outcrop around South Petherwin, Cornwall. Ansted (1838) described some of the clymenids from there and later de la Beche, in his monumental report, described the locality (Beche 1839f p.60) and in the accompanying faunal description John Phillips (1841) described many of the ammonoids in more detail, Phillips also described specimens from Wolborough Quarry, Newton Abbot, now known to be Middle Devonian in age. After this initial spate, and partly as a result of the authoritative accounts of these writers and of Sedgwick and Murchison (1840), little progress occured for almost forty years, although McCoy (1851) did give some new names to South Petherwin ammonoids. In 1877 J.E. Lee, an amateur geologist, announced the discovery of Upper Devonian goniatites at Saltern Cove and Clement Reid, in the same year, noted clymenids at Lower Dunscombe, Chudleigh. These discoveries apparently stimulated considerable interest among other geologists and over the next decades attention was ( >: m\' :'v«o i drawn by many authors to localities yielding goniatites. Commen• cing in 1889 G.P. Whidbome began publishing the results of his faunal studies of the South Devon limestones and he described new goniatite species from Wolborough, Lummaton and Barton Quarries, The year 1890 marks the first major contribution by W.A.E. Ussher of the Geological Survey. Over the next two decades Ussher discovered many new ammonoid localities whilst mapping the Torc[uay, Plymouth and Newton Abbot sheets. Ussher's contribution can scarcely be over-estimated ; not only did he become familiar with the Devonian geology of most of Devon, but also he travelled on the continent and was able to make shrewd comparisons between the Devonian of England and Germany and the Ardennes. At about the same time the Cornish amateur geologist Howard Fox began searching the North Cornish coast for fossils. Pox sent his finds to the leading palaeontologists of his day for determination and recorded his finds in a series of notes and papers (Fox 1894, 1900, 1905). In particular Pox noted the goniatite localities in Constantino Bay and at Trevone and near Cant Hill. His results were mostly quoted without modification in the later Survey Memoirs. With the publication of the Padstow Memoir (1910) and the Tavistock and Launceston Memoir (1911)» Clement Reid collated the work of several Officers of the Geological Survey and details were given of several new goniatite localities, such as that at Portquin, and redescriptions of others, such as those in the Launceston district. The inter-war period is marked by the work of L.G.