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Silurian Rugose Corals of the Central and Southwest Great Basin

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Silurian Rugose Corals of the Central and Southwest Great Basin Silurian Rugose Corals of the Central and Southwest Great Basin GEOLOGICAL SURVEY PROFESSIONAL PAPER 777 Silurian Rugose Corals of the Central and Southwest Great Basin By CHARLES W. MERRIAM GEOLOGICAL SURVEY PROFESSIONAL PAPER 777 A stratigraphic-paleontologic investigation of rugose corals as aids in age detern2ination and correlation of Silurian rocks of the Great Basin with those of other regions UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1973 UNITED STATES DEPARTMENT OF THE INTERIOR ROGERS C. B. MORTON, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director Library of Congress catalog-card No. 73-600082 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402- Price $2.15 (paper cover) Stock Number 2401-00363 CONTENTS Page Page Abstract--------------------------------------------------------------------------- 1 Systematic and descriptive palaeontology-Continued Introduction -------------------------------------------------------------------- 1 Family Streptelasmatidae-Continued Purpose and scope of investigation-------------------------------­ 1 Dalmanophyllum ------------------------------------------------- 32 History of investigation ----------------------------------------------­ 1 Family Stauriidae ------------------------------------------------------- 32 Methods of study-------------------------------------------------------­ 2 Cyathoph y llo ides-------------------------------------------------- 32 Acknowledgments------------------------------------------------------- 4 Palaeophyllum ----------------------------------------------------- 33 Identification of the Silurian System in the Great Basin---------­ 4 Family Pycnostylidae--------------------------------------------------- 34 Areal distribution of Great Basin Silurian coral-bearing rocks-­ 5 Stylopleura, new genus------------------------------------------ 34 Depositional and faunal facies of Great Basin Silurian coral- Family Tryplasmatidae------------------------------------------------ 36 bearing rocks ---------------------------------------------------------------- 5 Try plasma----------------------------------------------------------- 36 Great Basin Silurian reference sections --------------------------------­ 8 Solitary-rugate group -------------------------------------- 37 Mazourka Canyon reference section-------------------------------­ 8 Fasciculate-cylindrical group---------------------------- 37 Ikes Canyon reference section---------------------------------------­ 9 Rhabdocyclus------------------------------------------------------- 38 Roberts Creek Mountain reference section----------------------­ 10 Palaeocyclus -------------------------------------------------------- 39 Coal Canyon reference section--------------------------------------­ 10 Zelophyllum -------------------------------------------------------- 40 Northern Panamint Range reference section-------------------­ 12 Family Kodonophyllidae---------------------------------------------- 40 Lone Mountain reference section---------------------·-------------- 12 Subfamily Kodonophyllinae ----------------------------------- 40 Rugose coral zonation of the Great Basin Silurian----------------- 13 Kodonophyllum --------------------------------------------- 40 Zone A---------------------------------------------------------------------­ 14 Subfamily Mycophyllinae--------------------------------------- 41 Zone B ---------------------------------------------------------------------­ 14 Mucophyllum ------------------------------------------------ 41 Zone C ---------------------------------------------------------------------­ 15 Family Arachnophy llidae --------------------------------------------- 42 Zone D---------------------------------------------------------------------­ 15 Arachnophyllum -------------------------------------------------- 42 Zone E ---------------------------------------------------------------------- 15 Family Lykophyllidae ------------------------------------------------- 43 Stratigraphy and rugose corals of the Lone Mountain and Ryderophyllum ---------------------------------------------------- 44 Laketown Dolomite ------------------------------------------------------­ 16 Pycnactis ------------------------------------------------------------- 45 Rugose corals and geologic correlation of Silurian rocks within Family Cystiphyllidae-------------------------------------------------- 45 the Great Basin ------------------------------------------------------- 17 M icroplasma -------------------------------------------------------- 46 Zone A---------------------------------------------------------------------­ 20 Family Goniophyllidae------------------------------------------------ 46 Zone B ---------------------------------------------------------------------­ 20 Rhizophyllum ------------------------------------------------------ 46 Zone C ---------------------------------------------------------------------­ 21 Family Kyphophyllidae ----------------------------------------------- 46 Zone D---------------------------------------------------------------------­ 21 Kyphophyllum ----------------------------------------------------- 47 Zone E ---------------------------------------------------------------------- 21 Petrozium------------------------------------------------------------ 47 Great Basin Rugosa and correlation with distant Silurian rocks- 22 Entelophyllum ----------------------------------------------------- 48 Zone A---------------------------------------------------------------------­ 22 Entelophylloides--------------------------------------------------- 49 Zone B ---------------------------------------------------------------------­ 23 Subgenus Prohexagonaria, new subgenus----------- 50 Zone C---------------------------------------------------------------------­ 24 Neomphyn1a -------------------------------------------------------- 51 Zone D---------------------------------------------------------------------­ 24 Tonkinaria, new genus------------------------------------------ 51 Zone E ---------------------------------------------------------------------- 24 Family Chonophyllidae ----------------------------------------------- 52 Correlation of Lone Mountain and Laketown Dolomite---------­ 25 C honop hy llum ----------------------------------------------------- 52 Age conclusions based 6n Silurian Rugosa------------------~--------­ 26 Family Endophyllidae ------------------------------------------------- 54 Comparison of Silurian coralline rocks in the Great Basin A us tra lop hy llu m -------------------------------------------------- 54 with those of other regions---------------------------------------------­ 27 Subgenus Toquimaphyllum, new subgenus-------- 54 Depositional features of Great Basin Silurian coralline rocks Family Acervulariidae-------------------------------------------------- 55 in relation to the reef problem ----------------------------------------­ 28 Diplophyllum ------------------------------------------------------ 56 Dasycladacean algae in Great Basin Silurian coralline deposits­ 29 Genera with no family designation-------------------------------- 56 Classification of Great Basin Silurian Rugosa ----------------------­ 29 Salairophyllum ---------------------------------------------------- 56 Systematic and descriptive paleontology ------------------------------- 30 Denayphyllum, new genus------------------------------------- 56 Family Streptelasmatidae --------------------------------------------­ 30 Locality register---------------------------------------------------------------- 57 Rhegmaphyllum--------------------------------------------------- 30 References ----------------------------------------------------------------------- 59 Brachyelasma ------------------------------------------------------- 31 Index------------------------------------------------------------------------------ 63 III IV CONTENTS ILLUSTRATIONS [Plates follow index] PLATE 1. Dalmanophyllum, Brachyelasma, Rhegmaphyllum, Palaeocyclus, Rhabdocyclus, and Tryplasma. 2. Tryplasma, Palaeophyllum?, Stylopleura, and Maikottia. 3. Stylopleura and Palaeophyllum. 4. Kodonophyllum, Diplophyllum?, and Crassilasma?. 5. Mucophyllum, Arachnophyllum, and Cyathophylloides. 6. Ryderophyllum, Crassilasma?, and Pycnactis. 7. Tonkinaria, Microplasma?, Rhizophyllum, and Denayphyllum. 8. Chonophyllum and Cyathactis?. 9. Entelophylloides (Prohexagonaria) and Petrozium. 10. Entelophyllum and Tryplasma. 11. Australophyllum (Toquimaphyllum) johnsoni, n. subgen., n. sp. 12. Australophyllum (Toquimaphyllum), Australophyllum, and Salairophyllum?. 13. Kyphophyllum nevadensis, n. sp., and Neomphyma crawfordi, n. sp. 14. Kyphophyllum and Australophyllum. 15. Stylopleura, Rhabdocyclus, Palaeocyclus, Pycnostylus, Entelophyllum, and Australophyllum (Toquimaphyllum). 16. Brachyelasma, Stylopleura?, and Verticillopora. Page FIGlTRE 1. Index map showing principal areas of Silurian coral-bearing rocks referred to in text----------------------------------------------------- 3 2. Map of Great Basin showing major lithologic belts, distribution of Silurian reference sections, and coral localities------------- 6 3. Sketch of the Mazourka Canyon reference section, northern Inyo Mountains, Calif--------------------------------------------------------- 9 4. Sketch of the Roberts Creek Mountain reference section, Roberts Mountains, Nev---------------------------------------------------------- 11 5. Comparative diagram illustrating present usage of the stratigraphic
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