Вегип т 1895

- ОГОМЕ 111, NUMBER 352

NOVEMBER 18, 1996

The Molluscan Macrofauna of the Reklaw Formation, Marquez Member

(Eocene: Lower Claibornian), in Texas by

Christopher L. Garvie

Paleontological Research Institution 1259 Trumansburg Road Ithaca, New York, 14850 U.S.A.

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A Si m tS

Вегип т 1895 JY

у OLUME 111, NUMBER 352 МОУЕМВЕК 18, 1996

The Molluscan Macrofauna of the Reklaw Formation, Marquez Member

(Eocene: Lower Claibornian), in Texas

by

Christopher L. Garvie

Paleontological Research Institution 1259 Trumansburg Road Ithaca, New York, 14850 U.S.A.

ISSN 0007-5779 ISBN 0-87710-443-3 Library of Congress Catalog Card Number: 96-70357

Printed in the United States of America Allen Press, Inc. Lawrence, KS 66044 U.S.A.

——_———

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CONTENTS а аа ii au. 9 ЗОРО ИНЧА РАИ ры м BR а аа уз ув м Acknowledgments A RR RN ee о о Ў | осно РОТОРА А И ае Уе Корал n 9 | Stratigraphy WE CURE E eg авиа is MO" О sense т ab UN Turc o o wie 10 Locality Descriptions Scc Cu M e I cr ОИ ое eis 17 Collection and A I ip up РАТА И И ме B оО ны: x rem 18 B ow ИВ coe О НС анкс Y som 20 А Оаа ои Pagus beum: 20 | Systematic Paleontology RE ER тч 20 | ПИ ~ тен не ga ck А A а RR De n PURI ска вон кои 21 i Systematics о ио Mu aM E d a n E 21 | I "E 21 | ПИ ИН РУМЕ eres es ВИЛИ ИТ КЛ ПИТ Е NNNM m | mpeg ro RA RETTET Are 25 наа A ER ee ам i 27 | И RS DAR ee а 28 E dd АЛЕНЫ ORO O пон уа а: и = | о Bee ee u 29 | Це у ПИ они ВКО ОИ ЕО eee eae = | ee E quu an a A 31 ) EU ue A е ае ратне free ipie idi 31 ER se cem EEE E IP qu 32 "sg pana ld cdi NM и НАДИ DIN a cc as 32 E one E ce NN 33 | E vocem Dover cau E eee 34 е еге еее с 35 | a еа ar hana rae tips oria Ab аиан АЕ adu ы. 36 | Lcid wiped iiie apa cat СВИ МОТО СУВИ ОС таалада РОЗИ а Cbr ie 36 E E E 38 | Family er 39 A ee BEER 40 | MP ји | ее д 42 i ee ee een 43 и 4 и даде wb Ve pic ЕАО ВАНН SE НИ Ma er Sg = К A Vg ООО Орион за ие 45 | еен NU eius viel ET O ET E nk па e 45 руси DIRET E PEA a eb EN OE NY EE T RA TIS a Uh 46 | Це ии riori О оаа ан ERD A ом E пу ба 46 | Family OO ме АИ 00 4 dr А Гречин а sen ee TER 47 ee N en 48 EE Ни ur cr ERS eg 49 | ион FONT АИ РЕ ЕС A торса ЗОРИ ОРИОН 50 | A ренке, ои етае M об ами ат орат PA 51 | ви 52 | ten. Воло, éd Рисан NE RT У A dd 54 | ee ee a ee ee 54 | | nse il AA E анана ОСА ре зо 55 ни a dhe о ален rn are use areas 55 | ME ees) Pru eee ГОЛИТЕ LAM да es a E 56 | Family Cypraeidae теь ee an 57 \ НЫ ев саноеи an RUM Е, Оа Oa 60 ( M etm ie Moo ое е нен E а 63 | Family BEN ет пратка следа зоо 63 Family ЕН mU о СИЯ 64 Family ШОПОВ срез че ска QOO ET RO ааа маста a СКЕ 66

Е ИВ a Дес rorem e etae CO то

Iul Не ср он о е ако е аа mi ee 67 DU COSE ai eae pu И ad Leen ee Pee ER мек а ie mur. 68 ПРИЛИКЕ ОНО ит а M a a ey СД E По xcu ме Tn a ое 70 У битка Не о м 71 ДЕО ТОЕ e оса и Кан a al Er ET tM tot AE 7 о 75 пи А СОАВТ аи РАЗАРА ЛАА ПЛАНА sy GER Woon Re р SLT а a 80 ое и а а SON UE EU И 82 Puro ДОД than (abst а а м 85 Farny il os UU e E E 86 ЈЕНИ НИ NIE M ml d Lu I c E E UE. 87 A A As 87 ие оо INN AO E 89 PA ov cya De cie M ELT ML M nc DNE DU 90 о а AV EEISU ее 90 О T Rc mv clc uc UL. 105 luta Aroleciomicidns Е р ee 108 PAU UNDE те, ро ai ен НИЎ 112 Раа ее о NE 113 EA no ro даа P бан M UN C M E Ma Ва, 113 РАКИ от 115 Eau Phubmdde e senses cv ore ht E an а ас M 115 DU а TED. ee 116 м 117 PMY оо и MNT M 121 И а ПОР ЕЕ ео en не, 121 Py ит ли. со с. _ „|| > а 121 о 122 CO CA A ео О 122 В О, р о CS, CN 123

LIST OF ILLUSTRATIONS

Text-figure Page

O oe ТО О.

2. Paleogene correlation chart of Eocene and some Oligocene standard ages and formations in the Gulf Coast, California and western р о, a OIN S S И

22 SP НО ртошено compete RECHTE ом, о, PORT NES 12

4. Profile of two localities in Joe Taylor Branch, Milam County, Texas. Source of many species described in the text... v i

5. Maps showing the extent of the Reklaw Formation in Texas and fossil locations discussed in the text ..................... 16

6. Charts showing the abundance and diversity of the fauna distributed between seven habitats ©... cc cc 19

TABLES Table pag? 1. Table showing relative abundance of species found in Ridge Creek and Joe Taylor Branch and their inferred environment .....+*' P

foldout inside back СО

| THE MOLLUSCAN MACROFAUNA OF THE REKLAW FORMATION, MARQUEZ MEMBER | (EOCENE: LOWER CLAIBORNIAN), IN TEXAS

CHRISTOPHER L. GARVIE

10107 Old Orchard Ct. Skokie, Illinois 60076 USA!

ABSTRACT

An abundant and well-preserved molluscan fauna from the Marquez Shale Member of the Reklaw Formation in East and | Central Texas contains more than 188 species of molluscs, of which 123 are referred to new species, 6 to new subspecies, and | 38 can ђе referred to previously described forms. A further 16 can only be generically assigned. Four new genera, and two new

subgenera are defined. The majority of specimens came from two localities, Joe Taylor Branch of Two Mile Creek in Milam County, and Ridge Creek in Bastrop County. Two suites of specimens from the Texas Memorial Museum and the Philadelphia Academy of Natural Sciences respectively were also examined, as labels indicated a Reklaw age. Both of these suites were collected in the 1890's, and although possibly collected in the Reklaw formation, it is believed they are more likely to have | come from the Queen City or Weches formations; they are also treated in the text. The character of the deposits and the conditions under which the associated fauna of corals, bryozoans, vermes and vertebrate remains is found, suggest a near shore, open marine | environment. The fauna is a mixture of lagoonal elements, some with signs of wear, an open sea, near-shore component, and a | very well-preserved, size-sorted marine component from deeper water. A few brackish water species and one possible fluviatile | species could indicate the proximity of estuarine conditions. Most of the new species and genera were found in several exposures in Joe Taylor Branch of Two Mile Creek. Many of these localities were not previously known to be fossiliferous. The stratigraphy of several sections is described on Joe Taylor Branch, All previously described fossiliferous localities of the Marquez Shale Member of the Reklaw Formation were revisited, and collections made if possible. The following new genera and subgenera are proposed: Bivalvia: Tenuimactra; Gastropoda: Pseudometula, Trimalaxis, Hastula | (Bulbihastula), Surculoma (Volutapex), Eocythara. The following new species and subspecies are proposed: Scaphopoda: Den- talium (Antalis) palmerae, Fustiaria (Episiphon) aciculata, Cadulus bisissura; Bivalvia: Nucula cochlear, Nuculana (Jupiteria) | turgeo, Nuculana (Saccella) demissa, Litorhadia milamensis, Litorhadia undulata, Litorhadia valdefragilis, Barbatia (Acar) | salebrosus, Barbatia (Cucullaearca) reklawensis, Bathyarca claibornica, Pachecoa (Pachecoa) concentrica, Gregariella ridgei, | Amusium (Propeamusium) zinguli, Plicatula pustula, Hyotissa offemanae, Anodontia (Eophysema) reklawensis, Chama tayloren- | sis, Venericor densata reklawensis, Claibornicardia milamensis, Claibornicardia linguinodifera milamensis, Tenuimactra hodg- kinsoni, Eosolen shirleyi, Tellina (Eurytellina?) milamensis, Pitar (Calpitaria) turneri, Caryocorbula marquezensis, Notocorbula | marquezensis, Bankia (Lyrodobankia) petalus, Cochlodesma (Cochlodesma) ovalis, Cardiomya? fredsmithi; Gastropoda: Littorina | (Prosthenodon) eofasciata, Tubiola gracilis, Solariorbis discoides, Solariorbis conicus, Solariorbis? parsnaticoides, Theodoxus domicilium, Mathilda (Echinimathilda?) cribraea, Mathilda (Fimbriatella) iugum, Litiopa texana, Bittium (Bittium) tresquatrum, | Bittium (Bittium) ridgei, Glyptozaria americanae, Pseudomalaxis reklawensis, Pseudomalaxis acuta, Architectonica (Stellaxis) reklawensis, Architectonica (Patulaxis?) fimbiaea, Architectonica (Granosolarium) aldrichi caterva, Architectonica (Granosolar- | ium) geminicostata, Trimalaxis ora, Serpulorbis? multiclavus, Amaea (Scalina) macula, Amaea (Foratiscala) texana, Rugatiscala cooperi, Amaurellina plummeri, Natica (Naticarius) brevisulcata, Natica (Carinacca) moffitti, Polinices (Pliconacca) onustus | reklawensis, Sinum taylori, Sinum moveum, Postalia americana, Neosimnia scobina, Cypraeorbis bulbus, Phalium (Semicassis) | reklawensis, Ficopsis nucleoides, Hexaplex eoa, Mitrella (Clinurella) пипаш, Mitrella (Clinurella) пипа! lineata, Мета elon- | gatoides, Pseudometula gradus, Distorsio nucleoides, Colwellia bilineata, Tritiaria nodosa, Antillophos multilineatum, Bucci- } nanops ellipticum reklawensis, Bullia altilis harrisi, Fusinus claibornica, Latrius (Polygona) traceyi, Mazzalina conica, Surculites lapillus, Clavilithes parvetorbis, Clavilithes? acus, Levifusus? serrae, Cornulina minax dockeryi, Sycostoma texana, Michela trabeatoides carinata, Euryochetus punctatum, Ancilla (Olivula) staminea reklawensis, Admetula irregularis, Trigonostoma (Ven-

trilia) herbae, Trigonostoma (Ventrilia) elegantissima, Trigonostoma (Ventrilia) jonesae, Volvariella milamemsis, Conus (Lith- oconus) nocens, Coronia taylori, Hesperiturris nodocarinatus crassus, Hesperiturris? monilis, Hesperiturris? monilis levae,

| Domingella ridgei, Surculoma imbricata, Pyramimitra (Petrafixa) eocenica, Leptosurcula carinata, Eosurcula moorei reklaw-

| ensis, Tropisurcula milamensis, Tropisurcula (Eodrillia) planus, Tropisurcula (Eodrillia) grandis, Protosurcula? aurora, Spiro-

| tropis claibornica, Eocythara texanum, Eocythara lineata, Varicobela filum, Raphitoma (Microsurcula) georgei reklawensis,

| Raphitoma (Microsurcula) bastropensis, Raphitoma (Microsurcula) iuventae, Hastula milamensis, Hastula (Bulbihastula) am-

| pulla, Hastula (Bulbihastula) longifera, Mnestia rotunda, Mnestia confusa, Volvulella reklawensis, Retusa (Cylichnina) notata,

| Semiacteon texanum, Pyramidella (Syrnola) pirum, Pyramidella (Cossmannica) filamentosa, Pyramidella (Cossmannica) tundrae,

| Pyramidella (Cossmannica) tundrae zigguratum, Odostomia (Doliella?) ova, Turbonilla (Ptycheulimella) meta, Melanella min- utissima, Umbraculum tomaculum. Cephalopoda: Belosepia pennae.

Other proposed changes in taxonomic assignments include: Eodrillia is made a subgenus of Tropisurcula. Pyramimitra is i removed from the Mitridae and placed in the Turridae. Cyclostremiscus ахасииз replaces Cyclostremiscus ехасииз.

" Address for correspondence: Paleontological Research Institution, 1259 Trumansburg Road, Ithaca, NY 14850 USA

INTRODUCTION

I was prompted to begin collecting in the Reklaw by visiting stop 11 in a guide book by Е Е. Smith (1962), and discovering a handful of well-preserved molluscs. This led to an investigation of the creekside exposures in the shale, from the roadside locality to the nearby Brazos River. The Eocene molluscan fauna of Texas has been known since Ferdinand Roemer’s first discovery of fossils at Stone City Bluff on the Brazos River in 1846. Since that time a succession of workers, both professional and amateur, have collected and described the Texas faunas, particularly in the Weches and Cook Mountain formations.

Unlike Alabama, with its fine Sabinian and Clai- bornian Stage faunas, Texas has supposedly few sur- face exposures with good marine faunas between the Paleocene Midway faunas, monographed by Gardner (1933), and the Weches faunas of the lower middle Claibornian. A few brief references in the geological literature, however, gave reason to believe that such exposures exist. In 1980, I had the opportunity to in- vestigate the surrounding areas in more detail, and some productive exposures were indeed found. Initial investigation centered on the Reklaw exposures near the Brazos River, and this was later increased to in- clude the Reklaw exposures on and near the Colorado River. A search through the literature and further field work resulted in rediscovery of another locality in Rusk County. This report is the result of 12 years of intensive collecting in the Marquez Shale Member and is the first of a planned series. Later reports will cover the Seguin and other more minor faunas.

The Reklaw Formation consists of two members, the upper Marquez Shale member and the lower New- by Sand member. Both members weather rapidly, probably due to the decomposition of finely dissemi- nated pyrite in the glauconitic sandy layers. Exposures of both members examined proved to be sparingly fos- siliferous, usually with only leached imprints of the fauna. A few exceptional exposures in the Marquez Member provided the bulk of the specimens collected. The Marquez Shale Member has a higher clay and glauconite content than the Newby member, and fos- sils can be obtained after a flood has scoured the creeks, or by excavating. The lower Newby Member is also fossiliferous in east Texas, but is very prone to leaching due to the high sand content of the strata. Surface exposures in the east-central area between the Colorado and Brazos Rivers appear unfossiliferous. In easternmost Texas, Stenzel (1939) notes a fossiliferous layer in the Newby Member composed primarily of a subspecies of Venericor densata Gardner and Bowles, 1939; this area is not treated in this report. Some ad-

BULLETIN 352

ditional Reklaw molluscs were also found in the col- lections of the United States National Museum, the Academy of Natural Sciences of Philadelphia, and the Texas Memorial Museum. Few references have pre- viously been made to the Reklaw faunas, and then of- ten in such terms as “dwarfed faunas”, and “small gastropods similar to the Stone City species". In con- trast, my work in the Reklaw indicates that it contains a diverse and unusually well preserved macrofauna of molluscs, corals, bryozoans and fish remains.

This study is primarily a faunal description, and 45 such fills a chronological gap in the molluscan fossil record of the southern and eastern United States. The purpose is to provide a reference for the Reklaw mol- luscan faunas, and to stimulate further investigation of this neglected formation. All molluscan species are treated with the exception of the pteropods that were described in Hodgkinson et al. (1992). The limitations of time and residence have hampered the study some- what, and it is likely that other fossiliferous localities in the Reklaw remain to be discovered. The material obtained, including many unique specimens, indicates the fauna is far more diverse than previously suspect- ed, particularly as the present investigation only deals with a few exposures clustered around two areas; one centered on Joe Taylor Branch Creek in Milam Coun- ty, Texas and the second around Ridge Creek in Bas- trop County, Texas. The specimens obtained are Ше result of at least 100 collecting trips in the period 1980 to 1992. In addition to surface collecting, bulk samples of 20 kg. or more were normally collected on every trip from the small lenses of shell material that occur relatively frequently. The majority of the taxa, 25 might be expected, can be assigned with some confi- dence to an intermediate evolutionary position be tween similar Sabinian and Middle Claibornian forms:

ACKNOWLEDGMENTS

For the loan of specimens the author is indebted 10 Т. W. Waller and E Collier from the United States Ма tional Museum, S. Horenstein from the American MU- seum of Natural History, to P. Hoover from the Pale- ontological Research Institution, C. W. Copeland from the Geological Survey of Alabama, Dr. van den Bor? from the Louisiana Museum of Geoscience, G. Rosen berg from the Academy of Natural Sciences of phil- adelphia, D. T. Dockery Ш, from the Mississippi BV” reau of Geology, S. Tracey in England, and to C. Dur den from the Texas Memorial Museum where Ше ВУ reau of Economic Geology collections are now curated. Steve Tracey also helped in locating severa obscure references in the library of the Natural Histor’ Museum, London. I am particularly grateful to my three reviewers, W. D. Allmon, D. T. Dockery, aD“ ^

EocENE MOLLUSCS OF TEXAS: GARVIE 7

YEGUA Mount Tabor COOK MOUNTAIN Landrum Wheelock wlll ————— г Stone City с O са | SPARTA 3 Therrill WECHES Viesca Tyus QUEEN CITY The yA kN ay = $ 2. S pam Marquez REKLAW ————— | Newby 5 | CARRIZO

Text-figure 1.—Eocene stratigraphic units in Texas (from Stenzel et aL, 1957; Sams and Gaskill, 1990; and Yancey, pers. comm.).

E. Yancey for their thorough review of the draft; their Шапу comments and suggestions have greatly im- Proved the manuscript. In addition the extensive col- lections and library of the Natural History Museum, Ondon were kindly placed at the author's disposal While in that country by C. P. Nuttall and J. Cooper. he Bayerische Staatsbibliothek in Munich, Germany furnished many rare books not found elsewhere. In the ‘S.A., C. Jones and E. Benamy made the collections at the Academy of Natural Sciences in Philadelphia Available for study, and P. Hoover placed the Paleon- ‘ological Research Institution's collections at the au- thor’s disposal during several visits there. D. Steere Supplied several obscure references at the Smithsonian ‘stitution Libraries. The author is particularly grateful (0 C. р Nuttall and C. Jones for their expertise and Advice during the early part of this study as difficulties ose, During the long life of this study I have bene- Мед from Ше suggestions and help of many others, “nd to all of them I am very grateful. The study might ауе taken considerably longer without their help. My

wife Shirley spent many tedious hours checking many versions of the manuscript and for her patience and endurance I am very grateful.

HISTORY

The Reklaw Formation was regarded as being of Claibornian age as early as 1889 when Penrose (1889, pp. 29-30) described the Colorado River sections from Austin to Smithville. The first fossiliferous exposure downstream from the Travis County line is Bombshell Bluff, an exposure of Reklaw strata which was de- scribed as: "consists of thin interstratified layers of glauconitic marl, black clay, and dark siliceous sand with glauconitic specks, ...". Four miles below this first exposure is "Devil's Eye" where Penrose remarks on “similar ledges of the same strata". The “Devil's Еуе” locality does not appear to exist now, and it is believed from the faunal content that this locality should now be referred to the Queen City Formation, although uppermost Reklaw is possible. This fauna shows a greater similarity to the Weches fauna than any of the personally collected Reklaw material. The first determination of some fossils from this locality was made by Heilprin (1891); these were sent to him by Penrose from exposures on Devil’s Eye, these were identified as:

Conus sauridens (Conrad, 1833b) Pleurotoma Tuomeyi Aldrich, 1886 Pleurotoma nodocarinata Gabb, 1860d Distorsio (Personella) septemdentata (Gabb, 1860d) Astarte tellinoides Conrad, 1833c Nucula magnifica Conrad, 1833a Mitra? sp

Volulithes petrosus? Conrad, 1833a? Xenophora confusa Deshayes, 1832a Cytherea Nuttalliopsis Heilprin, 1881 Cardita tetrica Conrad in Wailes, 1854 ?Limopsis corbuloides Conrad, 1833b

The other species previously described as occurring in the Reklaw Formation are:

Ancillaria staminea Conrad, 1832b

Orthoyoldia psammotaea vivianensis (Harris, 1919)

Venericardia (Venericor) claiboplata Gardner and Bowles, 1939

Cancellaria sp. *

Latirus aff. L. moorei (Gabb, 1860) *

Murex sp. *

Natica sp. *

Pleurotoma cf. P. texanopsis Harris, 1895a* Pleurotoma carlottae Harris, 1899 *

Sigaretopsis sp. *

8 BULLETIN 352

Turritella n.sp. *

Turris cf. T. moorei Gabb, 1860 *

Corals 3 spp. *

Lirodiscus smithvillensis (Harris, 1895a) Athleta petrosa smithi Fisher and Rodda, 1964 Echinochilus texanum (Harris, 1895a)

Turritella turneri Plummer, 1933 Volutocorbis stenzeli Plummer, 1933

Volvaria gabbiana (Harris, 1895a) Xenophora confusa (Deshayes) Heilprin, 1891 Terebellum sp. (Harris, 1890)

Katherinella? trigoniata bastropensis (Harris, 1919) Venericardia cf. V. densata Conrad, 1845* Glycymeris sp. *

Angulithes elliotti (Stenzel, 1940)

Aturia turneri Stenzel, 1940

The species marked with an asterix were identified by Е E. Turner, and come from Ше “old Copper pros- pect”, Alsobrook land, Pullen Survey, 4 1/2 miles NE of Harwood, Caldwell County, Texas, and were de- posited in the Bureau of Economic Geology in Austin. The lists were compiled from information in Palmer and Brann (1965), Sellars et al. (1932), and Heilprin (1891). An attempt was made to locate Penrose’s spec- imens in the Academy of Natural Sciences in Phila- delphia, and also to locate the species identified by Turner in the Bureau of Economic Geology collec- tions, now transferred to the Texas Memorial Museum, but no positive identifications could be made. Whether all of the above species even came from the Reklaw is questionable. Several specimens now in the Texas Memorial Museum, that are identified as coming from the Reklaw Formation, and not personally found in the present study, were critically examined. These are be- lieved to be lowermost Weches Formation or Queen City Formation in age. Samples of matrix from within the aperture of two gastropods were found to contain foraminifera known to occur in the Weches. Whether the foraminifera also occur in the Reklaw is not known. The distance from the uppermost Reklaw lo- cality to the lowermost Weches on the Colorado river is only 2.4 km (=1.5 miles), and at the turn of the century, the two formations were united within the Timber Belt or Sabine River beds (Fisher, 1961), which might explain the mixing within the collections.

Other species whose range includes the Reklaw, but have not yet been recognized in the formation are:

Bonellitia tortiplica? (Conrad, 1865a) Bullia altilis subglobosa (Conrad, 1832b) Euspira leana (Palmer, 1937)

Galeodea dubia (Aldrich, 1885)

Species previously recognized in the Reklaw, or de-

scribed from another formation and whose stratigraph- ic range now includes the Reklaw, are as follows:

Orthoyoldia psammotaea vivianensis (Harris, 1919) Tellina (Arcopagia) trumani, Harris, 1897b

Mathilda cf. retisculpta aldrichi Palmer, 1937 Bullia altilis harrisi Palmer, 1928

Cornulina cf. armigera (Conrad, 1833a) Pleurofusia? huppertzi (Harris, 1895a)

Microdrillia rostratula Casey, 1903

Falsifusus ottonis (Aldrich,1886)

Ringicula trapaquara Harris, 1895a

Pyramidella (Cossmannica) perexilis (Conrad, 1865a) Limacina cf. taylori (Curry, 1965)

Limacina augustana (Gardner, 1951) Pseudoliva cf. santander Gardner, 1945 Athleta petrosa smithi Fisher and Rodda, 1964 Volutocorbis stenzeli Plummer, 1933

Stenzel (1953) reported a marine faunule from the Newby Member of the Reklaw in Cherokee County; which contained fish remains, molluscs, corals, bryo- zoa, and a sponge, without specifically identifying the fossils. The small pteropod mollusc, Limacina stenzeli Garvie in Hodgkinson er al., 1992, mentioned and fig- ured by Stenzel (1953, p. 82, fig. 42), and found by Stenzel in Cherokee County, is restricted to the Маг quez Member. It occurs abundantly in all fossiliferous Reklaw sections examined in this report.

Apart from the molluscs I have also collected following fauna from the Marquez Member:

the

Corals: Turbinola sp. Endopachys sp. Paracyathus 2 spp. Madracis ? sp. Bryozoans: Lunulites 2 spp. Encrusting Bryozoan spp. Annelids: Surpula sp. Arthropoda: Carapace fragment of a crab, genus indet. Crab claw, genus indet. Fish remains: Numerous spp. of shark and fish teeth Fish vertebrae and bones Whale bones

Since the time of Penrose, very little has been writ- ten on the paleontology of the Reklaw. Plu (1933) gives a short list of five species from the Co Е orado River valley, and a second list of 22 specie?

EOCENE MOLLUSCS OF TEXAS: GARVIE 9

from the dump at the side of the “old Copper pros- pect”, cf. locality 1. Some plant species are also listed from south Texas. Stephenson (1942, 1944) described Ostracoda from the Reklaw in Ridge Creek, Bastrop County (cf. localities 2—6). Foraminifera are described by Bannahan (1950), Hussey (1951), and Davis (1961). Stenzel (1950, 1953), provided extensive geo- logic reports on areas with Reklaw deposits, centered in the Tyler Basin of East Texas. Professor Е E. Smith (oral. commun.) said the late Dr. Е E. Turner of Texas A&M University worked on the paleontology of the Reklaw. Hodgkinson et al. (1992) described many Reklaw pteropods in their monograph of the Eocene Pteropods of the Gulf and Atlantic coasts. A site with abundant marine macrofossils occurs at a borrow pit exposing the Newby Sand Member in Rusk County, East Texas (cf, locality 25).

STRATIGRAPHY

The Reklaw Formation was first recognized as a dis- tinct unit by Wendlandt and Knebel (1929, pp. 1352- 1355), and was described аз “а basal layer, 20-40’ thick, of brown to dark blue, micaceous sandy clay; a middle layer, 4-15’ thick, of rather pure clayey glau- Conite containing plentiful fossils in the middle; and ап upper layer of up to 100’ of brown clay with streaks ОГ sand, green-sand, clay and clay-ironstone concre- tions", The type locality was given as the railroad cut Ш northeastern Nacogdoches County, 3.2 km (=2 Miles) northeast of the village of Reklaw in Cherokee County. Stenzel (1939), in his work in Cherokee County, concluded that the lower 6-12 m (=20-40 feet) of the section graded laterally into, and interfin- ered with the Carrizo Formation. The middle 1.2-4.6 m (—4—15 feet) was named the Newby Sand Member аа the upper 30 m (=100 feet) the Marquez Shale Member. Sams and Gaskell (1990), and Sams (1991)

ave examined the sequence stratigraphy of the Rek- law, showing the marine transgression occurred in re- Petitive stages of relative sea level rise. They also Identify deepening marine sediments, culminating in a Condensed section of 3—4.6 m (=10-15 feet), that has maximum diversity and abundance of foraminifera.

In south Texas, Trowbridge (1923) named certain Clay strata south of Carrizo Springs the “Bigford” and Supposed them to be part of the Wilcox Group; near

àrrizo Springs the Bigford apparently grades into the Carrizo. Gardner (1932), raised the Bigford to forma- tion rank, separating it from the Carrizo. In recent Years the term Bigford has fallen into disuse being *ssumed equivalent with the Reklaw. Stephenson (1953), in field work in East Texas, notes a ferruginous Conglomerate, previously thought to be terrace depos- tts, giving evidence for it being possibly the basal bed

of the Reklaw and overlying a possible eastern exten- sion of the Bigford. During the field work fossils were found in the conglomeratic bed, and the underlying stratum, but were not well enough preserved to fix the stratigraphic age as Reklaw. Stephenson did note that the fossils appeared to be distinct, but had a general similarity to forms and faunas of the lower Claiborne Group. I examined the ferruginous conglomerate sam- ples deposited at the Smithsonian Institution. A pre- vious investigator had made rubber casts from the fos- sil molds. I examined these casts and several species were found to be specifically identical with species described later in this report from the Reklaw. Amongst the casts, were two diagnostic species, Tri- tiaria nodosa n.sp. and Colwellia bilineata n.sp., both so far restricted to the Marquez Shale Member of the Reklaw formation. No such wide-ranging conglomer- ate bed is mentioned in Sams and Gaskell (1990), al- though in Gonzales County Sams (1991, p. 153) de- scribed a similar pebble-moulded, hematite-cemented, sandstone bed in the Guadalupe River section.

Elisor (1929) traced the Reklaw into Louisiana and placed it below the Sparta Sand and above the Cane River Formation, while Hussey (1949), and Guevara and Garcia (1972), correlated the Reklaw with the lowest part of the Cane River Formation in Louisiana. Further east in Mississippi and Alabama the Tallahatta Formation is generally regarded as the equivalent of the Reklaw and Queen City formations. Gardner (1957, pp. 573—578) discussed the lithology and pa- leoecology of the Tallahatta formation exposed in Lit- tle Stave Creek, Clarke County, Alabama. In the re- gion of the Rio Grande, the Reklaw (there regarded as equivalent with the Bigford) is approximately 213 m (=700 feet) thick, in Bastrop County—73 m (=240 feet) (Lyth, 1949), in Milam County—59 m (<195 feet) (Dunlap, 1955), in Robertson County—41 m (7133 feet) (Davis, 1961), in Leon County—30 m (= 100 feet) (Stenzel, 1953), and in northern Cherokee County—27 m (<90 feet) (Stenzel, 1953). Within Mil- am County, Dunlap (1955) divided the Marquez Shale Member into three lithologic units; a lower crossbed- ded stratum of mainly carbonaceous shales containing sands and irregular concretionary layers; a middle evenly-bedded stratum of dark-green glauconitic fos- siliferous shale; and an upper crossbedded stratum of shales with limonitic partings, iron-stone concretion- ary layers, and sand lenses.

A tentative correlation of the Reklaw with west coast faunas may be made via the foraminifera and calcareous nannoplankton zones. Hodgkinson ef al. (1992, p. 9) noted that the Reklaw falls within the nannoplankton zone 13 as used by Dockery (1986). Of those foraminifera species which Davis (1961)

10 BULLETIN 352

found restricted to Ше Reklaw, five were found Бу Weaver and Molander (1964) in the Eocene Cozy Dell or lower Sacate-Gaviota Formations of Santa Barbara County, California. These species are:

Anaomalina costiana Weinzierl and Applin Cibicides sassei Cole

Haplofragmatoides cf. mauricensis Howe and Ellis Robulus alato-limbatus (Guembel)

Trochammina claibornensis Howe

The only one of these not listed as rare is Т. clai- bornensis, and it is restricted to the lower part of the Cozy Dell Formation. Weaver and Molander (1964) regard these two formations as Late Eocene (Narizian) in age, and approximately contemporaneous with the Domengine-Tejon Formations. Squires (1987, p. 8) cites literature which places calcareous nannoplankton zone 13, as being contemporaneous with the upper Carpay and lower Domengine molluscan stages.

The occurrence of the planktonic pteropod, Lima- cina taylori (Curry, 1965) in Taylor Branch (Hodgkin- son et al., 1992, p. 20) also establishes the Marquez Shale member to be contemporaneous with the lower part of the London Clay formation in England.

Other exposures of the Reklaw at Wolf Den Branch of Mud Creek, south of Franklin, Robertson County, and on the upper reaches of Threemile Creek, (cf. Smith, 1962, p. 9, stop 11 of the field trip guide), were investigated and with the exception of a few imprints of Calorhadia sp. in the ironstone beds of the creek near Franklin, and in the clays of Threemile Creek, were found to be nonfossiliferous. In the northeastern parts of Cherokee County, where Stenzel (1953) has described fossiliferous exposures from both the Newby and Marquez members, all the fossils localities in the Marquez Shale are leached, so that only imprints re- main. The exposure in the Newby member mentioned by Stenzel (1953, p. 75) is now a very poor collecting site. To the west of Milam County, fossiliferous ex- posures are known from the Colorado River at several points, the first to be collected was known as Devil’s Eye locality, 12.8 km (=8 miles) SE of Bastrop, Bas- trop County, Texas. This locality produced the fossils described by Heilprin (1891), now in the Academy of Natural Sciences in Philadelphia.

The majority of specimens for this study came from Joe Taylor Branch (localities 12-22), and Ridge Creek (localities 2-7). Most of the exposures at these sites are sparingly but uniformly fossiliferous. Specimens tend to be very poorly preserved in the downstream part of the creek, owing to the permanently weathered condition of those exposures. Fossiliferous sediments in the Milam and Robertson County areas seem to be

a local feature restricted to Joe Taylor Branch, the Bluff on the Brazos River just upstream of the mouth of the creek, and a small unnamed creek 1 km (=5/8 mile) upstream. In 1986 beavers invaded Joe Таујог Branch, and their resultant dams made collecting all but impossible, so Ridge Creek in Bastrop County was investigated in more detail. The beavers are no longer in evidence on Joe Taylor Branch, but it has never recovered its former productivity. Lyth (1949, p. 28, 35), noted well-preserved macrofossils from two ex- posures on Ridge Creek. Localities 3 and 4 were the site of very fossiliferous silty/sandy lenses and have produced the bulk of the specimens from this creek.

Most of the specimens were found concentrated in two depositional modes. The first mode is where spec imens are found in thin, lenticular sandy lenses which appear to be storm deposits. The second mode where collecting is always good is a partially indurated glau- conitic bed that marks the base of the unit B in Joe Taylor Branch. It is believed this thin glauconitic zone easily recognized in the field, is the same zone that outcrops at the Colorado River banks at locality 7, and is also the same as bed 4c of Lyth (1949), in Ridge Creek. Bed 4c is about 3.4 m (=10 feet) above the Newby Marquez contact. It is not known if the Devil's Eye specimens examined in both the Academy of Nat- ural Sciences in Philadelphia and in the Texas Me- morial Museum derive from that same layer. Dumble (1892) described the strata at the Devil's Eye locality as follows: “The fossil-bearing bed is six to twelve inches thick, is semi-indurated, and composed almost entirely of glauconite and shells.", he also noted the same shell bed at Alum Bluff, at the mouth of Alum Creek, about 4.8 km (—3 miles) upstream of Smith- ville. None of the exposures examined for this report would appear to be as fossiliferous as those describe by Dumble.

Measured Sections

Where applicable, the techniques described 1 Swanson (1981) were used as the basis for sample descriptions. As sections for Joe Taylor Branch have not been previously published, two typical ones are outlined in Text-figure 4, and explanations on the OP” posite page. Unit B containing the clay-ironstone lay” ers can be readily followed from locality 15 10 the mouth of the creek at locality 23, and can serve 29 Е reference point for Ше sections. Lyth (1949), Sams an Gaskell (1990), and Sams (1991), may be consulte for a description of the Ridge Creek sections.

Locality Descriptions

Map references are in UTM metric grid notation ar the relevant USGS topographic map.

EOCENE MOLLUSCS OF TEXAS: GARVIE

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