·-· DEPARTMENT OF THE INTERIOR UNITED STATES GEOLOGICAL SURVEY GEORGE OTIS SMITH, DIRECTOR PROFESSIONAL PAPER 81 ·~· -:-· ..... ' . ' CRETACEOUS DEPOSITS OF THE EASTERN · ·GU-1F REGION AND .. SPECI~S OF EXOGYRA FROM THE EASTERN GULF ~- REGION AND THE CAROLINAS:-- ~·· .. •. ''. · BY LLOYD WILLIAM STEPHENSON ,...•. , .)j . .. .. .. ! : ! • •" : ! ~ •r• : •., II • ..• : :. : .~ ·~..... :. .: ·: . !. .... 'WASHINGTON GOVERNMENT PRINTING OFFICE 1914 REFERENCE 96297- CONTENTS. Page. Preface ............................................................................ ----.-.----·-·-----·.- 7 Cretaceous deposits of the eastern Gull region .............................................................. 9 Object and scope of the work ......................................... _· ................. : ............. 9 Past and present interpretation ..................................... ·_ ................................. 10 Lower Cretaceous .. ~ ....................................................................· ........ 10 Upper Cretaceous .............................................................................. 11 Eatly correlations ........................................................................... Jl Morton's correlation .................................................................. ·... 11 Tuomey's classification ............................. ·..................................... 12 Winchell's classification ................................................................. 12 Hilgard's classification ............................ ~ ..................................... 12 Smith and Johnson's classification ........................................................ 12 Tuscaloosa and Eutaw formations ............................................................ 12 East-central Mississippi. ................................................................ 12 Western Alabama .......................... : ........................................... 13 Readjustment of the nomenclature .........................................· _.. _.. _.. _... 13 Extent of the Tuscaloosa formation ..... ___ ... __ ......... ____ . _.......... _............... 14 Ext~nt of the Eutaw formation .. _................... _......... _.. _._ ............. : ... _.. 14 Selma chalk ...... _.... _............. _. __ .. _... ___ .. _. _...... _. _....... _.. _. _.... _.. _.. ____ . 15 Name .. ·-··············-······-·-·----·-······-·--··---------·-···----·······-····----- 15 Extent ...... _...... _......... _._.-- .... -........ --- ...... -- .......... -.- .... --- ... - .... 15 Character ...... __ ... : _............... _... __ . _. _. _.... _. _. __ . _....... _. _. _.............. _ 15 Lithologic subdivisions ........... __ ... __ .. __ ._ ... _....... _._ .... _......... _. __ ... _...... 16 Deposition .................. _._ ...... _._ ...... _...... _........ _._ .. -.... _.... _....... _.. _ 16 Paleontologic subdivisions .... __ ......... _.... _............ _.. _. _............ __ . _..... _.. 17 Ripley formation ...................... _....... _._. ____ ...... _._ .. _... _.. _.... _. ___ ..... _..... _. 17 11ississippi. ............. _.. _. _........ _.. ___ ........ _........ _.. __ ........ _. __ .......... 17 Tennessee and northward ..... __ ...... ___ . ____ .... ~ _...... ___ . _................ _..... _... 17 Alabama and Georgia .................. _. _. ____ ... _.... _.... _... _. _....... _........ _.. _.. 18 Summary of present classification ................. _.. __ .... _... _._._ ......... _. _. _.. _.. _....... _.... _.. 19 General sequence .............. _................ _... _. __ . ___ ... _......... - . - .... -.. -..... -.... _. _ 19 Lo,ver Cretaceous .............. _............. _. _. _. __ . ___ ........ _.... _. __ ........ _. _..... _.... _.. 20 Upper Cretaceous ............. -......... _.. _.... _... _.-.- ................. - ...... --.-.- ..... - .... 20 Tuscaloosa formation ................. _. ___ . ___ ................. _............. _....... _..... _.. 20 Eutaw formation ....... _.. _...... : . _. _. _.. _..... _...... _. _. _. _. ____ ........ _..... _.. _...... 20 TYI)ica1 beds ....... : ..... _________ ... _______ . ___ ·_________ .. ___ . ________ .... _: __ .. _. ____ _ 20 Tombigbee sand member ............. _....... _. _............ _. _. _..... _......... _..... _.. 21 Coffee sand member ............ _....... _. _........ _...... _. _. _. _..... _. _... _.. __ .. _. __ .. _ 21 Selma chalk .......... : ......... ____ .. _.. __ .. _........... _... _... _... _.:. __ ._ .... _..... _. ___ .. 21 Ri_pley formation .............. __ ..... _.... _.. _..... _............... _. _.... __ ....... _....... _. 21 Mississippi, Tennessee, Kentucky, and Illinois._._._._. ___ .... ____ . __ ... _.. _.... ____ .. _.. _. 21 Typical beds ......... _... _.... _._._._._ ............ -.... -.. -..... -................. 21 MeN airy sand member ......................................... _......... ·_ .... -.- .... _. 22 Alabama and Georgia .............. _..................................... _......... _..... 22 Typical beds ........ _..................................... · ............. : . ... , ....... 22 Cusseta sand member ............... _................................................ 22 Providence sand member ........................... _.... _.......................... 22 Surficial deposits ............................. _......................................... _....... 22 Faunal zones and subzones ..................· ......................................................... 23 Stratigraphic reh~tions ............. _............................................................ 23 Fossil localities .................................................................................. 23 . 3 4 CONTENTS. Cretaceous deposits of the eastern Gulf region-Continued. Faunal zones and subzones-Continued. Page. Distribution and range of the species.............................................................. 23 Basal beds of the Eutaw formation ..................................................... ·............ 25 Range of the species.......................................................................... 25 Correlation ........................ ~ . 25 Invertebrates .............. ·. 25 Plants.................................................................................. 26 Vertebrates .............. : ....................................... ·. 27 Exogyra ponderosa zone . 27 Range of the species ..................................................................... ·...... 27 Sub zones .. , . 28 Occurrence of the fossils................................................................... 28 Mortoniceras subzone ..............................................·...................... 29 Part of Exogyra ponderosa zone between the Mortoniceras subzone and the Exogyra costata zone.. 30 Correlation................................................................................... 31 Invertebrates ........................................................................... 31 The Carolinas ....... , ............................................................... 31 Ne.w- Jersey ......................................... , ........ , ..................... 31 Texas ................................................................. .'_._ .......... 32 Vertebrates ............................................................................ 32 Plants ....... : ............ , ......................... ·.................................. 33 , I Exogyra costata zone ............................................................................ 34 Range of the species ......................................................................... 34 Subzones .................................................................................. 36 Occurrence of the fossil~ ................................................................. 36 Liopistha protexta subzone ...................................... ~·- ..............· ......... 36 Extreme Upper Cretaceous beds ......................................................... 37 Correlation ........................................................ , ......................... 37 Invertebrates .......................................................................... 37 The Carolinas .................................................·· ..................... .'. 37 New Jersey ........................................................................ 38 Texas ................................................................................ 38 Vertebrates ............................................................................ 38 Plants .................................................................................. 39 Summary ........................................................................................... 39 Species and varieties of Exogyra from the eastern Gulf region and the Carolinas ............................. 41 Introduction ...................................................... , ................................ 41 Definition of the genus .............................................................................. 41 Geologic range of the genus ............................................................... ·............. 42 General description of the species and varieties ................. ·.· ..................................... 42 Geologic and geographic range ..................................... .' ................................... 43 Eastern Gulf region and the Carolinas .......................................·