Tulane Studies in Geology and Paleontology

TULANE STUDIES IN GEOLOGY AND PALEONTOLOGY

Volume 19, Number 1 July 31, 1986

THECALCAREOUSNANNOPLANKTONOFTHE MIDWAY GROUP (PALEOCENE ) OF ALABAMA

DAVID D. REIMERS REIMERS RESEARCH HOUSTON , TEXAS

CONTENTS I. ABSTRACT ...... 1 II. INTRODUCTION ...... 1 III . P REVIOUS STUDIES ...... 7 IV. L OCATION OF SAMPLED SECTIONS ...... 11 V. T ECHNIQUES AND PROCEDURES ...... 12 VI. R ESULTS AND CONCLUSIONS ...... 13 VIL A CKNOWLEDGMENTS ...... 18 VIII. S YSTEMATIC PALEONTOLOGY ...... 18 IX. REFERENCES ...... 46

ILLUSTRATIONS PLATES 1-14 beginning on p. 19

I. ABSTRACT IL INTRODUCTION The calcareous nannoplankton in sam The Midway Group of Alabama consists ples fr om the Paleocene Midway group of of three formations (figure 1 ). These are , in Alaba ma were examined and photo order of stratigraphic sequence: (1) the graph ed using both a light misroscope and Clayton Formation, which in central a scan ning electron miscroscope . Twenty Alabama is divided into the lower Pine seven species were identified, two of Barren Member and the upper McBryde which are described as new. The nanno Limestone Member ; (2) the Porters Creek plank ton distribution was used to correlate Clay, present only in western Alabama , the Alabama Midway Group with standard with the Matthews Landing Marl Member Paleocene nannoplankton zonations re at the top ; and (3) the Naheola Formation , sulting in the Pine Barren and McBryde present only in central and western memb ers of the Clayton Formation being Alabama , divided into the lower Oak Hill assigned to the Cruciplacolithus tenuis Member and the upper Coal Bluff Marl zone, and the Porters Creek Clay and the Member. Matth ews Landing Member being as Smith (1886) first used the term "Mid signe d to the Cyclococcolithina robusta way " in describing the strata exposed at zone. The nannoplankton distribution and Midway Landing on the Alabama River in abunda nces are related to the lithology Wilcox County , Alabama (figures 2, 3 ·and and depositional environments of the Mid 4). This section at Midway Landing was way u nits. The Clayton and Porter s Creek described by Smith as having a few feet of units contain certain species that are con black clay, which seemed equivalent to fined to or are more abundant in , particu that at Black Bluff on the Tombigbee River lar lithologic facies . The very shallow (Porters Creek Clay ), overlying about ten water deposits of the Naheola Formation feet of gray , argillaceous lime stone (the are barren of nannoplankton . McBryde Limestone ) with the nautiloid

EDITORIAL COMMITTEE FOR THIS PAPER: DAVID T . DOCKERY , III, Missis sippi Geological Survey, Jackson , Mississippi WILLIAM W. HAY, University of Colorado, Boulder, Colorado CHARLES C . SMITH , Tenneco Oil , Houston , Texas

1 2 Tulane Studies in Geology and Paleontology

Western Alabama Central Alabama Eastern

Coal Bluff Marl Member

Naheo1a -- - a I e t formation 0ak Hill Member

Porters Creek Clayton Clay Pormatian

McBrycleLimestone Member

Pine Barren Member

Figure 1- Formations and Members of the Midway Group in Alabama

Enclimatoceras. LaMoreaux and Toulmin Highway 21 in Wilcox County (figures (1953) described this Midway section as and 4). In the upper part of this member· part of the McBryde Limestone Member of the "Turritella rock" of Smith (1894 , cryst the Clayton Formation, consisting of four which consists of a sandy yellow hard calcareous claystone ledges interbed line limestone containing Turritel ded with gray marl. Since the Alabama alabamensis. The lower part of the me River has been dammed, only the upper her is a gray calcareous silt with indurat most claystone ledge is exposed. ledges. In Wilcox County the Pine Barre The Clayton Formation was named for Member has an estimated thickness of 1 . exposures near Clayton, Barbour County, feet (LaMoreaux and Toulmin, 1953) w Alabama by Smith (1892) . Exposures at the The McBryde Limestone Member · type locality, in a Central of Georgia Rail named by MacNeil (1946) for exposures road-cut one mile east of Clayton, consist roadcuts along Alabama Highway 21 · of approximately 12 feet of dense, crystal Wilcox County, approximately three mil line, gray limestone underlain by a tan, west of McBryde Station. The station clayey sand (figures 2 and 5). LaMoreaux longer exists but exposures can be fou and Toulmin (1953) described the Clayton along Highway 21 at a locality 0.2 m· in Wilcox County, Alabama, as consisting south of the intersection of Highway 21 of about 140 feet of massive limestone with Highway 28 in Wilcox County (figures some basal sand. In extreme western and 4). At this locality the strata consist Alabama the Clayton Formation consists of approximately ten feet of light gray Jim less than 20 feet oflimestone. stone, lying directly on the "Turritel The Pine Barren Member of the Clayton rock" of the Pine Barren Member . T Formation was named by MacNeil (1946) McBryde Limestone thickens to about for strata exposed in roadcuts on the south feet in eastern Wilcox County and Butl side of Pine Barren Creek, along Alabama County (LaMoreaux and Toulmin, 19 Midway Calcareous Nannoplankton 3 No. 1 Sucarnoochee Creek in Sumter County , F rther west it becomes more clayey and Alabama . The type locality of the Sucar in~ertongues with the lower part of the noochee Clay is Black Bluff on the Tom ers Cre ek Clay. Port bigbee River below its confluence with The Port er 's Creek Clay was named by Sucarnoochee Creek (figures 2 and 6 ). In Safford (1864) for exposures west of Mid western Alabama , the Porters Creek Clay dleton , Te nnessee . The e~':1ivalent de consists of 350 feet of black , jointed clay posits in Alabama were origmally called with some limonitic concretions. Approxi the Sucarno ochee Clay by Smith (in Smith mately 5 feet of glauconitic sand is present and Johnso n, 1887 ) from exposures along

Figure 2 - Counties containing type se.ction s of the Midway Group in Alabama 4 Tulane Studies in Geology and Pal eontology Vol. 19

Figure 3- Outcrop of the Midway Group in Alabama

at the top in the Matthews Landing Mem County. The dam on the Tombigbee Riv ber . In central Alabama the Porters Creek has resulted in most of the exposures Clay thins to about 100 feet and is more cal this locality being covered by water careous and fossiliferous. In this area , it river sediments. Only five feet of tan-gra blocky clay underlain by five feet of blac contains some claystone and sandstone lo ledges . Farther eastward, beds correlative blocky clay are now exposed during water . with the Porters Creek are included in the Fo Clayton Formation (MacNeil , 1946). In western Alabama the Naheola The Matthews Landing Member was mation is divided into the lower Oak Me named by Smith (in Smith and Langdqn , Member and the upper Coal Bluff 1894) for exposures at Matthews Landing her . The Oak Hill Member was named (195 on the Alabama River in Wilcox County , Toulmin, LaMoreaux and Lanphere Alabama (figures 2 and 4 ). Here the Matth for exposures in roadcuts near the town Alabama (fl ews Landing Member is a gray-green , Oak Hill in Wilcox County , sandy marl approximately 20 feet thick. ures 2 and 4 ). At this locality the Oak gra The marl thins westward to about five feet consists of approximately 51 feet of wi in Choctaw County . Due to the dam on the tan , laminated sandy and silty clay Alabama River only about ten feet of the carbonaceous layers. A thin bed of ligni Member. T Matthews Landing Member is exposed at marks the top of the Oak Hill Coal Bluff Marl Member was named present. Bl The Naheola Formation was named by Toulmin (1944) for exposures at Coal Smith (in Smith and Johnson , 1887) for ex on the Alabama River in Wilcox Coun as ·consis posures at Naheola Landing on the Tom Toulmin described the section bigbee River in Choctaw County, Alabama ing of gray , glauconitic, micaceous s (figures 2 and 7 ). LaMoreaux and Toulmin and clay · at the top , with large glauconiti (1953) described the exposures at this local sandstone concretions in a green san 16 feet of tan to gray, marl at the base. The section is now e ity as consisting of Me sandy clay with indurated ledges overlying tirely under water . The Coal Bluff , sandy, her is exposed at the type locality of approximately four feet of black · blocky clay. The Naheola Formation thins Oak Hill Member and at Shoal Creek and 4) . eastward until it disappears east of Wilcox Wilcox County (figures i Midway Calcareous Nannoplankton 5 No. 1

••••ou11 cou11n

F igure 4 - Locat ion of the sampled section s in Wilcox County . A - Midway Landing B - Sec onda ry McBryde section C - Matt hews Landing D - Seco nda ry Coal Bluff section E - Pine Bar ren section Figure 5 - Location of sampled section of F - McBryde section the Clayton Formation in Barbour Count y , G - Oak Hill and Coal Bluff sections Alabama

N 1

CHOCTAW COUNTY +---I.... .

1------i I"''·

Figur e 6 - Loca tion of sampled section of Fi gure 7 - Location of sampled section of the P orters C ree k Formation in Sumt e r the Naheola F ormation m Chocta w Count y, Alaba ma County , Alabama 6 Tulane Stud ies in Geology and Paleontology

the Naheola Formation . All of the Paleocene Midway units ex NacNeil (1946) stated that the Tertiary posed in Alabama represent marine envi deposits of central and western Alabam ronments , as indicated by the paleontology are composed of deeper water facie s tha (Toulmin , 1946) and the lithology (Murray , those of eastern Alabama. This is rep 1947). Bornhauser (1947) considered the resented in the Paleocene Midway Grou calcareous deposits of the Lower Tertiary by the occurrence of a basal sand an of Alabama and Mississippi to be trans sandy limestone in the Clayton Formatio gressive deposits ; with the shales and clays in easternmost Alabama . In central an to be open marine inundative deposits and western Alabama the basal Clayton con the sand units to be regressive deposits. tains a silty marl or clay. These facies re The distinct lithologic changes upwards in lationships indicate that the central an the Alabama Midway section support this western area of Alabama was more remot interpretation of the changing Lower Ter from the source of sediments than th tiary depositional environments. The basal areas on either side , and that the Tertia Clayton Limestone underlies the marine shoreline extended from eastern Georgi clay of the Porters Creek , which in turn to northern Mississippi (Toulmin , 1946). underlies the sandy , glauconitic, and ligni tic restricted marine or swamp deposits of

wwtlcal ICale CNJ ]'' ~ Gray pauari1ic ...., J• J CN7

CN 103 CN, Gray~

CNU Gray c:la,-, ll1t CN 106 IJ&hltan,crywlallneU-

CN 1•

CNJO,

CN 17

CN JI

CNlO ...... CNJZ2 -· • - CN23 -··- Figure 9 - Stratigraphic section of the Figure 8 - Stratigraphic section of the Member in Wilcox County Clayton Formation in Barbour County Barren Midway Calcareous Nannoplankton 7 No. 1 the III. PREVIOUS STUDIES on the calcareous nannoplankton of early Tertiary of France . Martini (1964) has Several studies have reported on the cal used his studies of the calcareous nannop careous na nnoplankton of the Midway lankton of Europe to construct zones of cal Bramlette and Martini strata of Alabama. careous nannoplankton of the Tertiary to the calcareous nanno (1964) des cribed be used in worldwide correlation. Hay et from the McBryde plankton i n one ~ample al. (1967) gave an excellent summary of Clayton Formation . Repre Member of the other previous works on Tertiary nanno sentatives of ten species of calcareous nan plankton . The work of Perch-Neilsen found in that sample. noplankton were (1969, 1971, 1977, etc. ) on Tertiary nan that coccoliths occur in They also stated nofossils includes studies of the Paleocene the Porters Creek Clay in sparse numbers. from Europe and several Deep Sea Dril hler (1967) used samples from Hay and Mo ling P~oject locations. the McBry de and Pine Barren members of the Clayton Formation in their correlation Subdivision of the Paleocene strata of early Terti ary rocks from the U . S. Gulf using calcareous nannoplankton has been Coast, Fra nce, and other worldwide loca attempted by several authors including tions. No list of the species found in the in Martini (1959, 1961, 1970, 1971), Stradner dividual sam ples was included in that re (1959; in Gohrbandt, 1963 ), Bramlette and port. Ellis an d Lohmann (1973) described a Sullivan (1961), Hay and Mohler (1965, new species of coccolith, Toweius peta 1967), and Sullivan (1964). The more recent losus, in sam ples from the Clayton Forma work of Hay et al. (1967) utilized previous tion and the Porters Creek Formation from studies to produce more useful zones Sumter Coun ty, Alabama . Cepek et al. based on continental and marine sedi (1968) repo rted finding no calcareous nan ments . Gartner (1971) erected zones (see noplankton in samples from the Pine Bar figure 18), modified from those of Ha y, ren Member of the Clayton Formation in which he correlated with planktonic Lowndes Coun ty, Alabama . Siesser (1983) foraminiferal zones adapted from Blow rep orted on the Paleogene nannoplankton (1969). biostratigraphy of Alabama . This study in Gartner (1971) pointed out that calcare cluded examin ation of samples from most ous nannoplankton zones generally are of the Alabama Midway units. based on samples from widely separated There are sev eral studies of the calcare geographic areas and represent different ous nannoplank ton of the Paleocene from lithologies and , in may cases, different de other locations . Sullivan (1964) discussed positional environments. For this reason, the c alcareous nannoplankton of the Ter Gartner speculated that such zonations at tiary of California, including several new have inherent weaknesses, which he specie s. Hay an d Mohler (1967) reported tempted to overcome by using cosmopoli-

CN 100 limestone Cray CN I

Gray limestone

J I'

I' J Figure 11 - Stratigraphic section of the McBryde Limestone Member at secondar y Figure 10 - Strat igraphic section of the location in Wilcox County (Sample CN 78 ~fo:8ryde Limest one Member at type local taken from 4 inch ledge of McBryde ity m Wilcox County Limestone at Midway type locality) 8 Tulane Studies in Geology and Paleontology tan species when possible as zonal indi MARKALIUS ASTROPORUS Zone - cators. His modification of the Hay et al. The interval from the first occurrence o (1967) zonation consisted of recognizing Markalius astroporus to the first occur one new mid-Paleocene zone, the Cyc rence of Cruciplacolithus tenius. Other lococcolithina robusta zone, and defining species common in this zone are; the Paleocene-Eocene boundary, based on Braarudosphaera bigelowi calcareous nannoplankton as falling within Braarudosphaera discula the Marthasterites contortus zone. Hay et Biantholitus sparsus al. did not base the Paleocene-Eocene CRUCIPLACOLITHUS TENUIS Zone - boundary on the calcareous nanno The interval from the first occurrence o plankton, but stated: "The Paleocene Cruciplacolithus tenuis to the first occur Eocene boundary, as defined on the basis rence of Cyclococcolithina robusta. The of evolutionary series of larger foraminif species of the Markalius astroporus zone era in Europe, lies within the Marthaster are still present along with Chiasmolithu ites tribrachiatus zone." danicus. The Paleocene calcareous nanno CYCLOCOCCOLITHINA R OBUST plankton zones of Gartner (1971) are based Zone - The interval from the first occur on the first or last occurrences of different rence of Cyclococcolithina robusta to th calcareous nannoplankton species and are first occurrence of Fasciculithus tym defined as follows: paniformis. Other species common in thi zone are: Markalius astroporus Cruciplacolithus tenuis Ellipsolithus macellus Toweius craticulus Chiasmolithus bidens FASCICULITHUS TYMPANIFORMI CNJ6 Zone - The interval from the first occur rence of Fasciculithus tympaniformis t the first occurrence of Heliolithus klei pelli. The species of the Cruciplacolith CN:,, tenuis and Cyclococcolithina robusta zone

CNU

CN 2' .J.. ..L c.ra,lftic:ac:eooa ...... L .L ..L CN 'I ..1.. ..J.: CN :Z, ..L ..L ..L ..L ..1.. ..L 01 ,1 ...L ..L ..L ..L CNJ2 ..L ..l.. ...L ..L _u ..L ..L -- - ~ wrtlcal CN-"' .... .l. ..L l0lle eo-ed ] 1' ]•· with--

Figure 12 - Stratigraphic section of the Por Figure 13 - Stratigraphic section of th ters Creek Formation in Sumter County Matthews Landing Member in Wilco County No. 1 Midway Calcareous Nannoplankton 9 pare still re sent . Other species common in Ellipsolithus distichus this zone a re : . Fasciculithus involutus Heliort hus concmnus DISCOASTER MULTIRADIATUS Chiasmolithus consuetus Zone - The interval from the first occur HELIO LITHUS KLEINPELLI Zone - rence of Discoaster multiradiatus to the The inter val from the first occurrence of first occurrence of Marthasterites bram Heliolithu s kleinpelli to the first occur letti. Species common in this zone are: ren ce of Discoaster gemmeus. Other Discoaster gemmeus spe cies common in this zone are: Discoaster perpolitus Braarudosphaera bigelowi Discoaster lenticularis Chiasmolithus danicus Discoaster mediosus Cyclococcolithina robusta Discoaster del icatus Fasciculithus tympaniformis Discoaster nobilis Chiasmolithus bidens Discoaster limbatus Heliorthus concinnus Zygodiscus plectopons Chiasmolithus consuetus Clathrolithus ellipticus DISCOASTER GEMMEUS Zone - The Chiasmolithus danicus interval from the first occurrence of Dis Cyclococclithina robusta coaster gemmeus to the first occurrence of Chiasmolithus consuetus Fasciculithus tympaniformis Heliolithus riedeli. The species of the MARTHASTERITES CONTORTUS Heliolit hus kleinpelli zone are still present Zone - The interval from the first occur except for Heliolithus kleinpelli. Also com rence of Marthasterites bramlettei to the mon in this zone is Dicoaster helianthus . last occurrence of Marthasterites contor HEL IOLITHUS RIEDEL! Zone - The tus. Species common in this zone are : interva l from the first occurrence of Discoaster binodosus Heliolithus riedeli to the first occurrence Discoaster diastypus of Discoaster multiradiatus. The species of the Discoaster gemmeus zone are still pre sent. Other species common in this zone are : OIJI Discoater del icatus Discoaster nobilis Discoaster limbatus CN60 Zygodiscus plectopons - CNU ~·· CN6' Uat,t - - l"llltJ...cly clay CN'7 Dartt llrown llpltic ...cly clay y., PY llloclcy clay CN61 y.,....iyclay CN'9 CNU ...... -- CN72 ...... - CN91

CNk _t=-~~ CN76 Dark llrown11D ludc clay - CNt, _.1-----"1 ...clypartil9

..tlcalocale J l'

Figur e 14 - Stratigraphic section of the Figure 15 - Stratigraphic section of the Oak Nahe ola Formation in Choctaw County Hill Member in Wilcox County 10 Tulane Studies in Geology and Paleontology Vol. 19

Discoaster perpolitus Paleocene zonation of other workers. Discoaster multiradiatus Berggren (1965) used the results of previ Discoaster gemmeus ous workers to produce a correlation of the Discoaster lenticularis Alabama Midway Group with planktonic Discoaster nobilis foraminiferal zones (see figures 20). Blow Zygodiscus plectopons (1969), in his widely used foraminiferal zo Chiasmolithus danicus five Fasciculithus tympaniformis nations, divided the Paleocene into Cyclococcolith i na robusta planktonic zones (see figure 18). The zonation of Martini (1970, 1971) has Comparing the Gulf Coast Paleocene and modified the previous zonations by erect foraminiferal zonations of Loeblich ing two zones between the Cruci Tappan, and Berggren to the standard di the placolithus tenuis and Fasciculithus tym visions of Blow and correlating these to paniformis zones: 1) the Chiasmolithus standard nannoplankton zones of Gartne danicus zone, and 2) the Ellipsolithus (see figure 21), the following conclusion macellus zone. Martini assigned numbers can be presented: (NP-1, etc.) to all of the nannoplankton (1) The Clayton Formation is within th as zones (see figure 19) and correlated them Pl zone of Blow, or the Markalius nan to existing foraminiferal zones. Siesser troporus and Cruciplacolithus tenuis (1983) assigned the following zones of Mar noplankton zones. tini to the corresponding Alabama Midway (2) According to Berggren's zonation, units: Pine Barren, NP-1 and 2; McBryde, the lower section of the Porters Creek Clay Porters Creek and Matthews Landing, correlates with zone P 2, or the Cruci NP-3 and 4; Naheola and Coal Bluff, NP-5. placolithus tenuis and Cyclococcolithina Paleocene foraminiferal zonations have robusta nannoplankton zones. been published, based on studies by Bolli (3) The Matthews Landing Member o (1957), Hay (1960), Subbotina (1953), etc. the Porters Creek Clay, and the Naheola Such works show varied placement of the Formation correlate with the P 3 foraminif Paleocene-Eocene boundary . Loeblich eral zone, or the Cyclococcolithina and Tappan (1957) established zones robusta, Fasciculithus tympaniformis, and shown in figure 20 based on the foraminif Heliolithus kleinpelli nannoplankton ers in samples from the Alabama Midway zones. strata. Their results differ from the Hay and Mohler (1967), examining sam ples from the McBryde and Pine Barren members of the Clayton Formation, recog nized three of Gartner's (1971) nanno plankton zones. The Markalius astropo zone and the Cruciplacolithus tenuis zone contain the nannofossil species common i each . The Fasciculithus tympaniformis CNIJ zone contains all of the species characteris

CNIO CNl2

wrtical ICUe wrtic&I ICUe J 1' J 1'

Figure 16 - Stratigraphic section of the Figure 17 - Stratigraphic section of the Coal Bluff Member at Oak Hill locality in Coal Bluff Member at Shoal Creek in Wil Wilcox County cox County Midway Calcareous Nan noplankton 11 No. 1

- CALCAREOUS AGE PLANKTONIC FORAMINIFERAL NANNOFOSSIL ZONES after Blow ZONES Marthasterites cantortus P5 GJoborot&lia velualensis Discoaster multiradiatus ...Globorot&lia pieUclomenarclii .--r-••ualfhl.B rte01u D1scoaster 2emme1a P3 Globorotalia ~ --- Heliolithus kleinpelli Globorotalia !!!9!!!!!! tVTnnan;•ormis

P2 Globorotalia in:inata Cyelococcolithina robusta Cloborotalia spiralis u.l C. compressa z C.inconst- u.l Clobocom- C. tri.nicladenais u claubjergenus Crucip&acolithus tenuis 0 Pl u.l c. triloculinoides ..I Cloborotalia < paeudobulloicles c. pseudobulloides a.

Clohiaeriria eugubina llolarkaliusastrooorus

Figure 18 - Paleocene Calcareou s N annoplankton Zonation and corresponding foraminiferal zonations (after Gartner 1971) tic of Gartner 's zone except for Fas hers indicate samples collected and pro ciculit hus tympaniformis. These occur cessed for calcareous nannofossils. rences are compared by the author with The following list gives the location of the standard foraminiferal zonations as the sampled sections and refers to the map shown in figure 22 . The Clayton Formation and figures illustrating each section . The is corr elated with the aforementioned nan numbers and the stratigraphic levels for noplank ton zones and the P 2 and P 3 each of the collected samples used in the foraminiferal zones of Blow. present study are shown on the illustrated stratigraphic sections . IV. LOCATIONS OF Midway type section - Midway Landing, SAMPLED SECTIONS Alabama River , Wilcox County , The samples used in this study include Alabama ; approximately 2 miles south mater ial collected from the type sections or of Highway 28 bridge crossing the type localities of all formations and mem Alabama River . bers of the Alabama Midway Group, with (McBryde Limestone ) the exception of the Coal Bluff Member of Tulane University locality number the Naheola Formation . The type section 1181. Sample CN 78; Figure 4 . of the Coal Bluff Member is inaccessible Clayton Formation type locality - section becau se of raised river levels but samples in Central of Georgia Railroad cut one of this member were collected from other mile east of Clayton , Barbour County , locations. Figure 3 shows the outcrop of Alabama . the Paleocene Midway Group in Alabama Tulane University locality number and t he counties where the type localities 1178. Samples CN 103 -122; Figures 5 -are studied. Figures 5-7 show the locations and 8. of the sections sampled . Samples were Pine Barren Member locality - Roadcuts taken at one foot intervals from each sec on the south side of Pine Barren tion. The letters CN before sample num- Creek on Alabama Highway 21, one 12 Tulane Studies in Geology and Paleontology Vol. 1

Alabama; approximately 5 mile NP9 Discoaster multiradiatus southeast of Canton Bend, Alabama . NP& Heliolithus riedeli Tulane University locality numbe 1183. Samples CN 24-35; Figures 4 an NP7 Discoaster E!!meus 13. Naheola Formation _type_ locality zII.I NP6 Heliolithus kle!!!l!!lli Naheola Landing on the Tombigbe II.I River just south of the pump house o NP, Fuciculithus tympaniformis the American Can Company, 2 mile ~..J NP• Ellil!!!?lithus macellus east of Pennington, Choctaw County, f Alabama. NP3 Chiasmolithus clanicus Samples CN 85-95; Figures 7 and 14. Oak Hill Member type _locality - 0.5 NP2 Cruclplacolithus tenuis mile northeast of Oak Hill post office on Highway 21, Wilcox County, NP 1 Markalius astropc,rus Alabama. Tulane University locality numbe Figure 19 - Paleocene Calcareous Nanno 1185. Samples CN 56-77; Figures 4 an plankton Zones of Martini (1970) 15. Coal Bluff Marl Member - (type loc ality not accessible) samples from ex mile south of the junction of Highway posures above the Oak Hill Member at 21 with highway 89, Wilcox County, the type locality of the Oak Hill Mem Alabama. her . Tulane University locality number Tulane University locality number 1179. Samples CN 5-23; Figures 4 and 1185. Samples CN 83-84; Figures 4 and 9. 16. McBryde Member type locality - Road Coal Bluff Marl Member secondary cut on Alabama Highway 21, 0.2 mile locality - Roadcut on Highway 265 at south of the junction of Highway 21 Shoal Creek, 5.5 miles south of Cam with Highway 28, Wilcox County, den, Wilcox County, Alabama. Alabama . Tulane University locality number Tulane University locality number 1187. Samples CN 79-82; Figures 4 and 1180. Samples CN 96-102; Figures 4 17. and 10. McBryde Member secondary locality -. Creek bed just off of Alabama high V. TECHNIQUES AND PROCEDURES way 162 one mile south of the junction A portion of each of the samples col of Highway 162 with Highway 28, Wil lected from the Alabama Midway sections cox County, Alabama . was processed to concentrate the cocco Tulane University locality number lith-size fraction. This was accomplished 1186. Samples CN 1-4; Figures 4 and by first removing the outer material from 11. the rock fragment to ensure a non-con Midway Landing type section (See Mid taminated portion. The cleaned sample way type section above). was then crushed with a mortar and pes Porters Creek Clay - type locality of tle. The powder was placed in a 50 ml Sucarnoochee Clay, Black Bluff on beaker to which approximately 30 ml of the Tombigbee River approximately buffering solution was added. An ul 2.5 miles east of Whitfield, Sumter trasonic clt!aner was then used to break up County , Alabama. the sample and disperse the clay-size ma Tulane University locality number terial. The beaker was allowed to stand for 1182. Samples CN 36-55; Figures 6 and two minutes to settle the sand-size mate 12. rial. The remaining suspension was de Matthews Landing Marl Member type canted into a second beaker and allowed locality - Matthews Landing on the to stand for two hours to concentrate the Alabama River, Wilcox County, finer sized material. The remaining sus- Midway Calcareous Nannoplankton 13 No. 1 ·on w as poured off and distilled water High Contrast Copy film. A Scanning Elec Pe nSI ed to the remammg. . se 1mend' t . Th e used to examine was a dd tron Microscope was also ie w as a llowed to settle for another and photograph representatives of species P . . t sam hours be fore t h e remammg wa er was seen in the light microscope. r o nte d an d discarded. This resulted in a s::plefree from any buffering solution, VI. RESULTS AND CONCLUSIONS hich c ould cause crystals to develop Samples examined from the Midway :h en the sample is dried. Group of Alabama contained representa Perman ent mounts of selected samples tives of 27 species from 18 genera of cal re the n prepared for examination with careous n annoplankton . Two are new we . . C d the Zeiss Photo m1~roscope usmg ae_ ax species described herein; the other species a mou nting medmm. Permanent shdes are forms previously described from the : ere ma de of every third sample in each of Paleocene or the Cretaceous . The five the Midway sections , or for each sample Cretaceous species are apparently re where a change in lithology was evident. A worked specimens; four of these are con second s lide was prepared of each sample fined to the basal Pine Barren Member of and exa mined to reduce the chance that a the Clayton Formation. Figure 23 shows single slide could be of poo~ quality with a the distribution and abundances of the resulting unfavorable specimen count. A species represented in the sampled sec standar d count of 150 specimens or 5 tions . travers es was made on each of the two The Pine Barren Member of the Clayton slides pre pared for each sample. Photo Formation contained representatives of 21 graphs were taken of representatives of species from 15 genera of calcareous nan each of the species present using Kodak noplankton. Ten of these species are con-

Loeblich and Berggren(1'6.5) TappanWU7)

Globorotalia Globorotalia 11,1 Salt Momtain velascoensl .. velascoensis i Formation spiralis zone < sub20ne Ill I Coal Bluff Member Globorotalia Globorotalia ~ pusilla-- Naheola Oak Hill I bulloides _I!!!!!!!! Formation Member j" subzone Globorotalia 0 angulata Matthews zone Landing I Member G Globorotalia Porters Creek uncinata 20ne Formation

Ill ~ z jlll McBryde Globorotalia Ill e Member compress.a :I

~..I Globigerinoides Globigerina daubjer . ~ ciaubEgensis ~ GloborotFa! Clayton Pine Barren trinidadensis Formation Member zone

Figure 20 - Foraminiferal Zonation by Loe blich and Tappan , and Berggr _en of the Gulf Coast Paleocene 14 Tulane Studies in Geology and Paleontology Vol. 19 fined to the Pine Barren Member . These Three relationships are apparent in th species are : Pine Barren Member : Braarudosphaeraturbinea 1) The samples composed of sandy cla Coccolithus species and silts generally yield more abundan Cribrosphaerella -ehrenbergii counts of total specimens than the lim Cruciplacolithus tenuis var . c stone samples; Eiff elithus turriseiffeli (2) Chiasmolithus californicus is com Heliorthus denticulatus Markalius reinhardtii mon in the Pine Barren Member and · Prediscosphaera cretacea confined to samples consisting of claye Toweius petalosus silts , but is found in the overlying McBryd Prinsius cf. P . martinii Limestone, indicating that no lithologic r Common species, or those appearing in lationship between this species and more than fifty percent of the samples of sociated sediments seems to exist ; the Pine Barren Member, are: (3) Toweius petalosus is present only i Chiasmolithus californicus the lower half of the Pine Barren sectio Coccolithus species and is more abundant near the bottom o Cruciplacolithus tenuis var. a the section. There is no apparent relatio Cruciplacolithus tenu1s var. b between the other species present or the· Markalius _reinhardtii abundances and the lithology of the sam Neococcolithes protenus Thoracosphaera multiperforata ples. Tharacosphaera saxea The McBryde Member of the Clayto Thoracosphaera cf. T. imperforata Formation contained representatives of 2 Zygodiscus sigmoides species from 10 genera of nannoplankton. Prinsius cf. P. martinii Five species are confined to the McBryd Of these, the four that appear in greatest Member: abundance in the Pine Barren Member Prinsius dimorphosus samples are Coccolithus species, Crucip Chiasmolithus consuetus lacolithus tenuis var. a, Thoracosphaera cf. Coccolithus crassus var. a T. imperforata, and Zygodiscus sigmoides. Coccolithus crassus var . b Coccolithus orbiculatus

Nannofossllzones of Gartner, 1971

Naheola Heliolitt.Js kleinpelli Formation

Fasciculitt.Js tympaniformis Matthews Landing C:r:clococcolithina robust& Porters Creek Clay

Crucl2lacolitt.Js tenuis

Clayton Formation Markalius astrOl!!!!US

Figure 21 - Provisional Calcareous Nannoplankton zonation of the Alabama Midway based on foraminiferal zones of Blow 15 No. 1 Midway Calcareous Nannoplankton The samples examined are not from a cally above the other two samples , as the · gle strati graphic section , thus the pri stratigraphically higher Matthews Landing si:r y relati onship that can be determined Mermber of the Porters Creek Clay also rsth at of re lative abundance and preserva contains Prinsius martinii but not Prin tion. Sam ple C~-100 showed ~he poorest sius dimorphosus. reservati on with many specimens bro The Porters Creek samples contained ~en . Sam ple CN-78, ~rom the ~ype lo~ality calcareous nannoplankton only in very of the Midway , contained specimens m ex small numbers . Only two species were pre cellent con dition . Species common to all sent , Cyclococcol ithina robusta and thr ee McBryde samples are : Zygodiscus sigmoides, both of which also Chiasmo lithus californ icus occur in one sample of the Matthews Land Coccolit hus cavus var. a ing Member . The representatives of these Coccolit hus crassus var. b species were only in fair condition, appar Coccolit hus orbiculatus ently due to partial solution. Cruci placolithu s tenuis var. b con Marka lius astroporus The Matthews Landing Member Neococcolithes protenus tained 18 species of 12 genera of calcareous Prinsiu s martin ii nannoplankton . Three species are con Thoracosphaera cf. T. imperforata fined to the Matthews Landing Member : Zygodisc us sigmoides Braarudosphaera bigelowi Cyclococcolithina cf. C. robusta The fo llowing species were common to Discolith ina versa abu nda nt in at least two of the three Four species appear in all three samples : McBry de Member samples : Prinsius martin ii Prin sius dimorphosus Coccolithus species Coccolithus cavus var. a Heliorthus concinnus Thoracosphaera cf. T. imperforata Thoracosphaera cf. T . impeeforata One noti ceable point of nannofossil distri Only two species, Prinsius martin ii and bution in the McBryde Member is that Coccolithus species , are common to abun Prinsiu s martinii is more abundant in dant in two of the three samples . Sample sample CN-78, and that this sample does CN-26 was more diverse in the number of not contain Prinsius dimorphosus . This in species represented, but most were pre dicates that sample CN-78 is stratigraphi- sent only in rare numbers .

Foraminifer Nannofossil Zones Zones (Blow, 1969) (Gartner, 1971)

Globorotalia FasciculithJs llc:Bryde Member tympaniformls zone z ~ ~ < :I Globorotalia Cruci2IacolithJs a: Pine Barren Member IS\Cinata tenuis ~ zone P2 zone ~ - ~.... u Markalius Pine Barren Member astrol)Orus zone

Figure 22 - Midway Calcareous Nannoplankton Zones after Hay and Mohler (1967) 16 Tulane Studies in Geology and Paleontology Vol. 1

MION~Y ... 0• CLAYTON PORTERSCREEK ..•-4 • 0 0 • * z i 'i f [ ~ :: f I l!I ~ ... i • ~ "' ffl "' • . I I• I u0 •Ill =:.o.::--- -ii l~l~tlU 1:1111111IAMl'LI# • lraarudolllNera Wlll!!!!!!i • lrun--1--halll'a bftilwa • • Qllaanoli-- • •• • • • • • Qllaanoli-5!!!!oml011 • • Cocm',;i._Ceccoli- ..- -· • • •• ·*·• • • • .COC<:ali- a. .._ ...... • Ceccoli-~ ...... •OO Cnc0D11iliii a--·II ••• Ceccoli-arlllculaNI • Cnc0D11iliii a . • Olc:coll-arlllculallll ••O o••••• • 0 * *· Ceccoli_...,... •• ~--II! ••••• o 0 • • • • ••• •••••• • 0. • • Bi:8!....~~--11- -· . • -.c • 0 ••• • Ill • • ~ n ~~--iii Dlacolilhlna..... • Ill • IWf.W- 1llrriaifl.U • • •• • • • • • ~aandlna • •• ~_...... _____ dlnticulatua • ••• • • •• • • • • •• • • _.....~ •• • • Mlcula ...... •• • • •• •• • • • • Nmc:accDlitt.. aula .. * * ,._.,_._ ••• *** Prlnll .. ffilf1lnil • •• • •O•O ~a. 11r1N1.. martlnil • • l'Nldi~awtaeea • • ••• •• oe •• • n.1 •- a IIIUhiDlllrtcrata • •O•• •O •• • n. ••• ••••••••• • • • n;e=::;_,----- .... •·*·· 1 ...... ••• ••o•o• ••• • • • Zr-di-• umokm

Figure 23 - Distribution and abundance of Calcareous Nannoplankton ·in the Alabama Midway Group. (Formations and Members not shown were barren ofnannoplankton) Midway Calcareous Nannoplankton 17 No. 1

The samples from the Naheola Forma The overlying Oak Hill and Coal Bluff tion and the Oak Hill and Coal Bluff mem members of the Naheola Formation are , bers of th e N aheola were barren of cal composed of sandy clays with lignitic careous na nnoplankton . The samples from glauconitic , and micaceous layers indica the type locality of the Clayton Formation tive of very shallow marine or swamp con were also barren of nannoplankton, ap ditions . Both of these units are barren of pare ntly due to the recrystallization of the nannoplankton. The clays and sandy clays of the type locality of the Naheola Forma limestone. The distr ibution and abundances of the tion must have also been deposited in very calcareous nannoplankton are representa shallow environments since no nanno tive of the changing environmental condi plankton were found in the samples from tions durin g the deposition of the Midway this unit. units. Th e calcareous deposits of the The examination of the samples from the Clayton unit represent a shallow marine Midway Group of Alabama results in the environme nt with an abundance of cal placement of; careous nannoplankton . The overlying (1) The Pine Barren and McBryde mem Porters Creek Clay was deposited in a bers of the Clayton Formation in the more open-marine environment (Bor Cruciplacol ithus tenuis zone of Cartner nhauser, 1947) but contains only two (1970), based on the presence of Crucip species of nannoplankton present in rare lacolithus tenuis and Markalius astroporus · numbers. This indicates either that the en in samples from both members. vironment was unfavorable for nanno (2) The Porters Creek Clay and the plankton, possibly due to turbid water , or Matthews Landing Member in the Cy that pre servation of the nannoplankton clococcolith ina robusta zone of Gartner was poo r as is evidenced by the poor con (1970), based on the presence of Cyclococ ditions of the specimens seen in the sam colithina robusta in samples from both ples. The two species present are more units, and on the presence of Cruci abunda nt in the Porters Creek Clay than in placolithus tenuis and Markalius as the Matthews Landing Member and may troporus in the Matthews Landing sam be indic ators of the environmental condi ples. tions. Heliorthus concinnus and Chiasmolithus The Matthews Landing Member is cal consuetus , indicators of the Fasciculithus et careous and represents a more shallow tympaniformis zone, as defined by Hay , marine environment, similar to that rep al. (1967), are present in the Pine Barren resente d by the Pine Barren and McBryde McBryde, and /or Matthews Landing sam membe rs of the Clayton Formation . This is ples. These species are not indicators of evidenc ed by the fact that all three units the Fasciculithus tympaniformis zone in contain some of the same species . But the the Alabama Midway Group since they are environ ment of the Matthews Landing restricted to the calcareous facies . If these Membe r also must have been slightly dif two species were indicators of this zone ferent from that of the Clayton units as in most of the Alabama Midway section dicated by: would have to be placed in the Fas (1) Th e species common to the Clayton ciculithus tympaniformis zone, based only units a nd the Matthews Landing Member on the presence of these two species with are gen erally present in more samples Fasciculithus tympaniformis being absent. and/or greater numbers in individual sam Thus the three lower Paleocene nannofos ples in the two stratigraphically lower sil zones would have to be contained in the Clayton members ; lower part of the Pine Barren Member. (2) These two Clayton units also show a The absence of the key species Fas greate r diversity in number of species ; ciculithus tympan iformis agrees with the (3) Some species appear and are con findings of Hay and Mohler (1967 ), who as fined to the Matthews Landing Member. signed a section of the McBryde Member This ma y be due to the restriction of these of the Clayton Formation to the Fas species to the environment present at the ciculithus tympaniform is zone, but stated time of deposition of this unit , or to the that this species was absent. Hay and evolution and extinction of certain forms . Mohler (1967) assigned two sections of the 18 Tulane Studies in Geology and Paleontology Vol. 19

Pine Barren Member to the Markalius as Order PYRMNESIALES troporus and Cruciplacolithus tenuis Christensen , 1962 zones. The Pine Barren samples used in Family COCCOLITHACEAE the present -study are apparently from the Kamptner , 1928 higher stratigraphic portions of the Pine Subfamily COCCOLITHOIDEAE Barren section and represent only the Kamptner , 19?8 Cruciplacolithus tenuis zone. Genus COCCOLITHUS Schwarz , 1894 The zonation resulting from the present Type speci es: Coccolithus oc ean icus Sch warz , study of the nannoplankton in the 1894 Alabama Midway Group agrees more with Definition: Elliptical placoliths with th the provisional nannoplankton zonation distal shield larger than the proxim based on correlation of standard nanno shield and joined to the proximal shield b plankton zones with Gulf Coast Paleocene a hollow tube . Both shields concave on th ), than foraminiferal zones (see figure 21 proximal side . with the Midway nannoplankton zonation of Hay and Mohler (1967 ). CoccoLITHUSCAVUS var. a VII. ACKNOWLEDGMENTS Plate 1, figures 1 and 2 1967, p . Coccolithus cavus HAY and MOHLER , The author wishes to thank Hubert C 1524, pl. 196 , figs. 1-3; pl. 197 , figs. 5, 7, 10, 12 Skinner, Harold Vokes , and Stefan Gart PERCH-NEILSEN, 1969b , p. 322, pl. 33, figs ner for their assistance and advice during 3-6. the course of this study. Ericsonia cava (HAY and MOHLER ), PERCH NIELSEN , 1969a, p. 61 , pl. 4 , figs. 13, 14. VIII. SYSTEMATIC PALEONTOLOGY Description : This large elliptic The classification followed in the present placolith has a distal shield composed o study is that of the Code of Botanical approximately 48 elements which show Nomenclature. slight dextral imbrication . The central are Kingdom PLANTAE forms a depression that is partially filled b Subkingdom PROTOBIONTA a cycle of elongate trapezoidal elements Rothmaler, 1948 The small central opening makes up a Division PHAEOPHYTA Wettstein , proximately one-fifth of the total width o emend., Rothmaler, 1949 the placolith . The proximal shield is com Subdivision CHRYSOPHYTINA posed of the same number of elements Rothmaler, 1949 the distal shield but has a serrate margin. Class COCCOLITHOPHYCEAE Size : Maximum length 10 microns. Rothmaler, 1949 Occurrence: This species was report Subclass COCCOLITHOPHYCIDAE from the Paleocene of France and Aust · Rothmaler, 1949 and was found in the Pine Barren an

PLATEl Figures 1 , 2. Coccolithus cavus var. a ; Sample CN-78 la. Cross-polarized light, x3250 lb . Transmitted light , x3250 2. Electron micrograph, x9500 , distal view Figure 3. Coccolithus cf. C. cavus var . a ; Sample CN-26 3a. Cross-polarized light, x3250 , 70° to polarizer 3b. Transmitted light, x3250 3c. Phase-contrast , x3250 Figure 4. Coccolithus species ; Sample CN-5 4a. Cross-polarized light, x3250 , 70° to polarizer 4b. Transmitted light, x3250 *The cross-polarized light photographs were taken with the long axes of the specime parallel to the polarizer unless stated otherwise. Midway Calcareous Nannoplankton 19 No- 1

. t b

3b 3c

PLATE 1 20 Tulane Studies in Geology and Paleontology Vol. 1

McBryde members of the Clayton Forma Occurrence : This form was found in th tion and the Matthews Landing Member of McBryde Member of the <;:Jayton Forma the Porters Creek Clay . tion.

CocCOLITHUS cf. COCCOLITHUS CAVUS. a var CoccOLITHUSCRASSUS var. b Plate 1, figure 3 Plate 2, figure 2 Description: The distal shield of this Coccol ithus crassus BRAMLETTE and SUL large elliptical placolith is composed of ap VAN, 1961, p . 139, pl. 1, figs. 4a-d. proximately 50 elements surrounding an Description : The distal shield of this el indistinct central area. No central opening liptical placolith is composed of approxi can be seen . mately 60 elements which meet alon Discussion: Specimens included here straight sutures . The large central area · are similar but not identical to Coccolithus partially closed by the apparently flat wid cavus var. a. These forms have the same collar that surrounds the central openin general size and structure of Coccolithus The central opening makes up appro · cavus var. a but have an indistinct central mately one-fourth of the total width of th area . placolith. Si ze: Maximum length 10 microns. Discussion: This species differs fro Occurrence : Representatives of this Coccolithus crassus var. a in being slightl species were found in the Pine Barren and more elliptical, having a slightly small McBryde members of the Clayton Forma central opening, and having an apparentl tion and the Matthews Landing Member of flatter collar. the Porters Creek Clay. Si ze: Maximum length 8 microns . Occurrence: This form was found in th COCCOLITHUSCRASSUS .var a McBryde Member of the Clayton Form Plate 2 , figure 1 tion . Description: This elliptical placolith has a distal shield composed of approximately CoccOLITHUS ORBICULATUS n. sp. 60 elements which meet along straight su Plate 8, figure 5 tures . The large central area contains a Description : This circular placolith h thick collar and a wide central opening. approximately 45 elements in the dis The central opening makes up approxi field. The large central area has a sm mately one-third of the total width of the central opening , which makes up appro • placolith . mately one-sixth of the total width of th Si ze: Maximum length 8 microns. placolith .

PLATE2 Figure 1. Cocclithus crassus var. a ; Sampl e CN-1 la . Cross-polarized light, x3250 lb. Transmitted light , x3250 le. Interference-contrast , x3250 Figure 2. Coccolithus crassus var . b ; Sample CN-1 2a. Cross-polarized light, x3250 2b. Transmitted light, x3250 2c. Oblique illumination, x3250 Figure 3. Discolithina versa (Bramlette and Sullivan), n. comb. ; Sample CN-32 3a. Cross-polarized light , x3250, 90° to polarizer 3b . Cross-polarized light, x3250, 45 ° to polarizer 3c. Transmitted light , x3250 Figure 4. Braarudosphaera bigelowii (Gran and Braarud) Deflandre ; Sample CN-29 4a . Cross-polarized light, x3250 4b. Transmitted light, x3250 4c. Phase-contrast, x3250 Midway Calcareous Nannoplankton 21 No. 1

1a 1b 1c

2 a 2b 2c

3 a 3b 3c

4b 4c

PLATE2 22 Tulane Studies in Geology and Paleontology Vol. 19

Discussion: This species differs from bility and occurred only in very low num forms of Coccolithus cavus in being circu hers. lar. It differs from certain species of Mar Size: Maximum length 8 microns . kalius in that the central area is open. Occurrence: These forms were found i Size: Maximum · diameter 6 microns. the Matthews Landing Member of the Po Occurrence: Representative of this ters Creek Clay, and in the Pine Barre species were found in the McBryde Mem and McBryde members of the Clayton Fo ber of the Clayton Formation. mation. Holotype: USNM 3~8226-CN-1-19 (11.2 x 1.6) (Plate 8, figure 5) . Genus CHIASMOLITHUS Hay, Mohle and Wade, 1966 Type species: Chiasmolithus oamaruensis ( CocCOLITHUScf. CocCOLITHUSORBICULATUS flandre) Hay, Mohler, and Wade , 1966. Plate 8, figure 6 Description: Placoliths with a large ce Discussion: This group includes forms tral opening spanned by an X-shap that are identical to Coccolithus or structure. The distal rim is larger than th biculatus except for being slightly larger proximal rim. and showing a slight dextral imbrication of the elements of the distal shield. CHIASMOLITHUSCALIFORNICUS Size: Maximum diameter 6 microns. (Sullivan) Hay and Mohler Occurrence: This form was found in the Plate 5, figure 3 McBryde Member of the Clayton Forma Coccolithus aff. C. gigas BRAMLETTE an tion. SULLIVAN, 1961, p. 140, pl. 1, fig . 7 a-d. Coccolithus californicus SULLIVAN, 1964, CoccoLITHUS species 180, pl. 2, figs . 3 a, b; 4 a-b; SULLIVAN, 1 Plate 1, figure 4; Plate 13, figure 1 p. 31. Description: These elliptical placoliths Chiasmolithus californicus (Sullivan). HAY an have distal shields of approximately 30-60 MOHLER, 1967, p . 1527, pl. 196, figs. 18-20; p . elements. The size of the central area var 198, fig. 5 ies. The interference pattern consists of a Description: This elliptical placolith h dark rim with a dark cross in the central a distal shield composed of approximatel area, which separates into two V -shaped 60 elements, which show a slight dextr lines when rotated 45 degrees. imbrication . The large central area is spa Discussion: Included here are two dif ned by an X-shaped structure. Both of th ferent coccolith species not assignable to bars of the X have a sigmoid shape, on others noted, which showed a high varia- bar being longer than the other. The X

PLATE3 Figure 1. Cyclococcolithina robusta (Bramlette and Sullivan) Gartner ; Sample CN-39 la. Cross-polarized light, x3250 lb. Transmitted light, x3250 le. Interference-contrast, x3250 Figure 2. Cyclococcolithina cf. C. robusta ; Sample CN-26 2a. Cross-polarized light, x3250 2b. Phase-contrast, x3250 Figures 3, 4. Prinsius cf. P. martinii; Sample CN-11 3a. Cross-polarized light, x3250 3b. Transmitted light, x3250 4a. Cross-polarized light, x3250 4b. Phase-contrast, x3250 Figure 5. Braarudosphaera turbinea Stradner; Sample CN-20 5a. Cross-polarized light, x3250 5b. Transmitted light, x3250 5c. Phase-contrast, x3250 Midway Calcareous Nannoplankton 23 No- 1

1b 1c 1a

2 a

4 a

PLATE3 Vol. 19 24 Tulane Studies in Geology and Paleontology offset slightly to the major and minor axis Si ze: Maximum length 11 microns. of the ellipse. Occurrence: This species was reporte Discussion: The species differs from from the Lodo Formation of California an Chiasmolithus consuetus in being large from Pont Labau in France and occurs i For and having more elements in the distal the McBryde Member of the Clayton shield. The bars of the central X-shaped mation. structure are sigmoidally shaped in both species but are more nearly aligned with Genus CRUCIPLACOLITHUS Hay and the equal axis of the ellipse in Chias Mohler, 1967 molithus consuetus. Type species : Cruciplacolithus tenuis Size: Maximum length 9 microns. (Stradner ) Hay and Mohler, 1967 Occurrence: This species was originally Definition: Elliptical placolith with both described from the Lodo Formation of shields being concave on the proximal California and at Pont Labau in France , side. The open central area is spanned by and was found in the Pine Barren and a central cross whose bars are aligned wit McBryde members of the Clayton Forma the major and minor axes of the coccolith. tion and the Matthews Landing Member of the Porters Creek Clay. CRUCIPLACOLITHUSTENUIS var. a Plate 11, figure 4 CONSUETUS CHIASMOLITHUS Description : The distal shield of this el and Mohler (Bramlette and Sullivan) Hay liptical placolith is composed of approxi Plate 5, figures 1 and 2 mately 45 elements and has a central de Coccolithus consuetus BRAMLETTE and SUL pression with a sloping margin. The very LIVAN , 1961, p. 139, pl. 1, figs. 2 a -c. opening is spanned by a thi~ 1963, p. 74, large central STRADNER in GOHRBANDT , is aligned with the major and , p. 180, pl. cross, which pl. 8, figs. 10-12. SULLIVAN , 1964 . The central , 1965, p. 31. minor axes of the ellipse 3, figs. 1 a-b ; SULLIVAN two Chiasmolithus consuetus (Bramlette and Sulli opening makes up approximately van ). HAY and MOHLER , 1967, p. 1526, pl. thirds of the total width of the placolith. 196, figs. 23-25; pl. 198, fig. 16. Discussion: This form differs from tenuis var. b in having a Description: This regularly elliptical Cruciplacolithus and a narrower rim, placolith has a distal shield composed of larger central opening differs from var. c in having a larger approximately 60 slightly trapezoidal ele and opening and a thinner collar. ments, which show a slight dextral imbri central Si ze: Maximum length 7 microns. cation. The central opening is spanned by Occurrence: This form was found in the an X-shaped cross bar more or less aligned and McBryde members of the with the axes of the ellipse . This central Pine Barren Clayton Formation and the Matthews structure is composed of overlapping rhombs of calcite. Each of the bars of the X Landing Member of the Porters Creek curve slightly in opposite directions giving Clay. each bar a sigmoid shape. CRUCIPLACOLITHUSTENUIS var . b Discussion: The specimens seen in the Plate 11, figures 1 and 2 Midway samples differ from previously de scribed forms in having more elements in Heliorthus tenuis STRADNER , 1961, p. 84, text the distal shield. figs. 64, 65.

PLATE4 Figures 1-3. Markalius astroporus (Stradner) Hay and Mohler; Sample CN-78 la. Cross-polarized light, x3250 lb. Transmitted light, x3250 le. Interference-contrast, x3250 2a. Electron micrograph, x4800, proximal view 2b. Electron micrograph, x19,100, proximal view 3. Oblique illumination, x3250 Midway Calcareous Nannoplankton 25 No- 1

PLATE4 26 Tulane Stud ies in Geology and Paleontology

Coccolithus helis STRADNER in GOHR ing is spanned by a thin cross , which BANDT , 1963, p . 74, pl. 8, fig. 16; pl. 9, figs. 1. aligned with the major and minor axes 2. BRAMLETTE and MARTINI , 1964, p. 298- the ellipse. 299, pl. 1, figs. 10-12; non pl. 7, figs. 5 a, b, 6. Discussion : This form differs fro Cru.ciplacolithus tenuis (Stradner ). HAY and Cruc iplacol it hus tenuis var. a in having MOHLER , 1967, p. 1527, pl. 198, fig s. 1, 17: broader rim , a thicker collar, and non pl. 196, figs. 29-31. PERCH -NIELSEN . a smalle 1969a, p . 59, pl. 1, figs. 7, 8; PERCH central opening ; and from Cruci NIELSEN , 1969b, p . 323, pl. 34, figs. 1-7. placol ithus tenuis var . b in being slight! smaller, having a Description: This elliptical placolith has more open central area and having a distal shield composed of a broad rim of a thinner collar. Size: Maximum length 8 microns. approximately 40 to 55 elements , and has a Occurrence : This form was found in th central depression with a sloping margin . Pine Barren Member of the Clayton For The moderate-sized central opening ma y be almost entirely closed by the broad mation. cross-shaped central structure that span s Subfamily CYCLOCCOLITHOIDEAE the central opening. The cross is aligned with the major and minor axes of the el Hay and Mohler , 1967 lipse. Scanning electron micrographs show Genus CYCLOCOCCOLITHINA the bars of the cross to be composed of two (Kamptner) Wilcoxon, 1970 rows of flat rhombs that overlap. The cen Type species : Cyclococcol it hina l eptopo tral depression may be covered by a cycle (Murray and Blackman ) Wilcoxon , 1970. of small short elements . Definition : Circular placoliths having Discussion: This variety of Crucip circular central perforation . lacol ithus tenuis is larger than variety a and has a broader rim and a much smaller CYCLOCOCCOLITHINAROBUSTA central opening . Cruciplacolithus tenu is (Bramlette and Sullivan ) Gartner var. c is smaller and has a thinner collar Plate 3 , figure 1 and a larger central opening than this vari Cyclolithus? robustus BRAMLETTE and SU ety . LIVAN, 1961, p . 141, pl. 2, figs. 7 a-c. Si ze: Maximum length 10 microns. Cyclococcolithina robusta (Bramlette and Sull ' Occurrence: This form was found in the van ). GARTNER , 1967, p. 104. Pine Barren and McBryde members of the Description: This circular placolith has Clayton Formation and in the Matthew s large central opening with approximate!. Landing Member of the Porters Creek 55 elements in both the distal and proxim Clay. shields. The distal shield is larger than th proximal shield. The large central openin CRUCIPLACOLITHUSTENUIS var. C is bordered by a narrower collar. Plate 11, figure 3 Discussion : The forms examined in th Description: The distal shield of this el present study have two shields of elemen liptical placolith is composed of approxi forming a placolith instead of a sing) mately 55 elements. The broad rim sur grooved ring as reported by Bramlette an rounds a central area with a thin collar and Sullivan. No electron micrographs wer a large central opening. The central open- taken of this species so the actual structur

PLATE5 Figures 1 , 2. Chiasmolithus consuetus (Bramlette and Sullivan ) Hay and Mohler ; Sample CN-1 la. Cross-polarized light, x3250 lb . Transmitted light, x3250 2. Electron micrograph, x4800, distal view Figure 3 . Chiasmolithus californicus (Sullivan ) Hay and Mohler; Sample CN-1 3a. Cross-polarized light, x3250 3b. Transmitted light, x3250 Midway Calcareous Nannoplankton 27 No-1

,. 1b

3a 3b

PLATE 5 28 Tulane Studies in Geology and Paleontology Vol. 19 of these forms is not known. All of the tures . The interference pattern shows a specimens of this species seen in the dark cro ss in the central area with the rim Alabama Midway samples appear to have being black. been partially dissolved. Size: Maximum diameter 9 microns. MARKALIUS ASTROPORUS (Stradner ) Occurrence: This species was reported Hay and Mohler from the Paleocene of California and in Plate 4, figures 1-3 samples from the Blake Plateau, and was Cycloccocolithus astroporu s STRADNER in found in the Porters Creek Clay and the GOHRBANDT , 1963, p. 75 , pl. 9 , figs. 5-7; text Matthews Landing Member of the Porters figs. 3-2 a, b . Creek. Markaliu s in versus (Deflandre ). BRAMLETTE and MARTINI, 1964, p. 302, pl. 2, figs. 4-9; non pl. 8, figs. 2 a-b. MARTINI, 1964, p. 49, pl. 6, cf. CYCLOCOCCOLITHINA CYCLOCOCCOLITHINA figs. 9, 10. PERCH-NIELSEN , 1968, p. 72 , pl. ROBUSTA 24, figs. 1-8; pl. 25, fig . l ; text fig . 35; PERCH Plate 3, figure 2 NIELSEN , 1969a, p. 326 ; text fi g. 5 ; PERCH Description : This circular placolith has NIELSEN , 1969b, p. 63 , pl. 3, figs. 5-6. approximately 40 elements and a very Markalius astroporus (Stradner ). HAY and pl. large central opening. MOHLER, 1967 , p. 1528, pl. 196, figs. 32-35; 198, figs. 2, 6. GARTNER, 1967 , p. llO . Discussion: These forms seem to be the inner portion of specimens of Cyclococ Description: This circular placolith has a colithina robusta, which have undergone distal shield larger than the proximal partial solution . The size, and shape is shield showing a slight sinistral imbrication similar to Cyclococcolithina robusta. They of the elements. Both shields are com occur stratigraphically higher than the posed of 32 to 36 elements. In the scanni ng level of common Cyclococcolithina robusta electron microscope the proximal shie ld and may represent reworked forms of the shows a four-rayed primary structure plus latter. auxiliary elements in the central area sur Size: Maximum diameter 6 microns. rounded by a thin cycle of coun Occurrence : This form was found in the terclockwise curving elements . Matthews Landing Member of the Porters Si ze: Maximum diameter 9 microns. Creek Clay. Occurrence: This species has been re ported from Cretaceous and Paleocen localities and was found in the Pine Barre Genus MARKALIUS and McBryde members of the Clayton For Bramlette and Martini , 1964 mation, and in the Matthews Landi Type speci es: Markalius in versus (Deflandre ) Member of the Porters Creek Clay. Bramlette and Martini , 1964 Definition : Circular placolith composed MARKALIUSREINHARDTII Perch-Nielsen of two closely appressed shields connected Plate 10 , figure 5 by a hollow tube . The distal shield is larger Terge stiella barne sae part (Black). RE and shows counterclockwise curved su- HARDT , 1966, pl. 1, figs. 1-2; text fig. 2.

PLATE6 Figures 1-3. Prinsius dimorphosus Perch-Nielsen 1. Electron micrograph, x20,300 , Sa mple CN-100 2. Electron micrograph, x30,400 , Sa mple CN-100 3a. Cross-polarized light, x3250; Sample CN-1 3b. Transmitted light, x3250; Sample CN-1 3c. Phase-contrast, x3250; Sample CN-1 Figure 4. Toweius petalosus Ellis and Lohman 4a. Cross-polarized light, x4050; Sample CN-10 4b. Phase-contrast , x4050; Sample CN-10 Figure 5. Prinsius cf. P. martini; Sample CN-7 Electron micrograph , x18,300 No. 1 Midway Calcareous Nannop lankton 29

1 2

PLATE 6 30 Tulane Studies in Geology and Paleontology Vol. 19

Markalius reinhardti i PERCH -NIELSEN , 1968, Zygolithus concinnus MARTINI , 1961, p. 18, pl. p. 76 , pl. 23 , figs. 6-8, text fig s. 34c, 38; 3, fig.35; pl. 5 , fig. 54. BRAMLETTE and PERCH-NIELSEN , 1969a, p . 63-64, pl. 3 , figs. MARTINI, 1964 , p. 304 , pl. 4 , figs. 13, 14; non 2-4; pl. 7 , figs. 13, 14; PERCH-NIELSEN , pl. 7, figs. 3 a , b. SULLIVAN , 1965, p. 38 . 1969b, p. 327, pl. 34 , fig. 8. Zygol ithus chiastus BRAMLETTE and SULLI Description : This circular placolith has a VAN , 1961, p. 149 , pl. 6, fi gs . 1 a-d; 2 a, b; 3 a, strongly sloping distal shield composed of b. STRADNER in GOHRBANDT, 1963, pl. 10, figs. 1-3. SULLIVAN , 1964, p. 187 , pl. 7, approximately 40 overlapping elements. fig. 12. The overlapping edge of the elements is in Heliorthus concinnus (Martin ). HAY clined counterclockwise and near the center, MOHLER, 1967, p. 1533 , pl. 199 , figs. 16-18: changing direction near the middle of the pl. 201 , figs. 6, 7 , 10. PERCH-NIELSEN. rim and extending to the outer edge. The 1969a, p. 62 , pl. 5 , figs. 6-8. wide central area contains two sets of ele Description: This elliptical coccolith has ments. The outer set consists of straight a distal rim of stongly imbricate triangular elements, which are inclined at the same elements surrounding an inner cycle of angle as the elements of the outer rim. The broader triangular elements that show no inner set of central elements consists of at imbrication. The open central area is span least three elements making a tall stem ned by an X-shaped structure that is like structure. Reinhardt's illustrations formed of elongate laths. One of the bars of show this structure to have three sides . the structure is offset so that it does not Discussion: The forms seen in the Mid form a straight bar. The amount of the way samples show a distinctive interfer offset varies as is shown in the figures of ence pattern consisting of two dark cross Bramlette and Sullivan (1961). es, one on the outer rim and one in the cen Discussion: The offset bar and thicker ter . The raised central structure is very rim of this form distinguishes it from Neo distinctive in the light microscope. coccolithes protenus. The laths of the cen Size: Maximum diameter 5 microns. tral structure are wider than those of N. Occurrence: This species was reported protenus. Martini's (1961) origina l figure from the Maastrichtian and Danian of De shows the offset nature of the central struc nmark and was found in the Pine Barren ture and makes this a distinctive feature to Member of the Clayton Formation. be used in the identification of this species. Family ZYGODISCACEAE Size: Maximum length 7 microns. Hay and Mohler, 1967 Occurrence : This species was reported Genus HELIORTHUS from Paleocene strata in various parts of the world Bronnimann and Stradner, 1960 and was found in the sam ples from the Pine Barren Member and the Type species: Heliorthus fallax Bronniman McBryde Member and Stradner , 1960 of the Clayton Forma· tion, and the Matthews Landing Member Definition: An elliptical ring with an X of the Porters Creek Clay. shaped structure spanning the central opening . HELIORTHUSDENTICULATUS Perch-Nielsen HELIORTHUSCONCINNUS (Martin) Plate 13, figures 2-5 Hay and Mohler Heliorthus denticulatus PERCH-NIELSEt, Plate 12, figures 3 and 4 1969a, p. 62, pl. 5, fig 5.

PLATE7 Figure 1. Thoracosphaera cf. T. imperforata Kamptner; Sample CN-14, Cross-polarized light, x3250 Figure 2. Thoracosphaera saxea Stradner: Sample CN-18, Cross-polarized light, x3250 Figures 3-5. Thoracosphaera multiperforata n. sp. 3. Cross-polarized light , x3250; Sample CN-7 4. Cross-polarized light, x3250; Sample CN-14 5. Electron micrograph, x9300; Sample CN-7 No. 1 Midway Calcareous Nannoplankton 31

1 2

3 .. 4 ~ ,,,. .. ~ Ml \ . • , .._I '

PLATE 7 32 Tulane Studies in Geology and Paleontology Vol. 19

Description: This elliptica l coccol ith is ments surrounding an inner cycle of more is formed of a tall elliptica l outer rim made of irregular elements. The central opening is steeply inclined, over lapping flat element s. spanned by an X-shaped structure that X These overlay a cyc le of irregular basal made of elongate laths . The bars of the elements, which may fill part of the large are arranged so that they form a smaller central area. Th e central area is spanned angle with the short axis of the ellipse and by a thin cross made of bars that are not a larger angle with the long axis. aligned with the axes of the ellipse and Ii Size: Maximum length 7 microns. at a ngles to eac h other. Th e bars are made Occurrence: This species was reported of e longate lat hs. from various wor ldwid e Paleocene Size: Maximum length 6 microns. localities and was fo und in the Pine Barren Occurrence: Thi s spec ies was reported and McBryde members of the Clayton For from the P a leoce ne of Denma rk and was mation, and the Matthews Landing Mem found in the Pin e Barren Member of the ber of the Porters Creek Clay. Clayton Form at ion. Genus ZYGODISCUS Gen us NEOCOCCOLITHES Bramlette and Sullivan, 1961 Sujk ows ki, 1931 Type species: Zygodiscus adamas Bramle tte , 1961 Type species: Neococcolithes lososnensis Su.1- and Sullivan kowski, 1931 Definition: Coccolith s with an ellipt ical Defini tion: Thin e lliptical rim with a rim surr ounding a central area with a ves large central opening spanne d by an H tige of a basal plate and a centra l open ing shap ed structure . spann ed by a transverse bar. The bar has more than one seg ment of different calcite N EOCOCCOLITHES PROTENUS orientation. (Br amlette and Sullivan ) Hay and Mohler Pl ate 12, figures 1 , 2 Z YGODISCUS SI GMO IDES Br am lette and Sullivan Zygolithus protenus BRAMLETTE and SULLI Pl ate 14, figure s 1-5 VAN, 1961, p. 150, pl. 6, figs. 15 a, b. Zygodiscus sigmoides BRAMLETTE and SU Sul Chiphragmalithus protenus (Br am lette and LIVAN , 1961, p. 149, pl. 4, figs. 11 a-e . SULLI livan). SULLIVAN , 1964, p. 179, pl. 1, fig. 1. VAN, 1964, p. 187, pl. 5 , figs. 7 a-c. BRAM Sulli Neococcolithes protenus (Bramlette and LETTE and MARTINI, 1964, p. 303, pl. 4 , pl. van). HAY and MOHLER , 1967, p. 1533 figs. 4, 5. SULLIVAN , 1965, p. 38, pl. 6, figs 199, figs. 19-21; pl. 201, fig. 9. PERCH Sa, b, 9a, b. HAY and MOHLER, 1967, p NIELSEN, 1969, p. 64, pl. 5, fig. 4. 1532, pl. 199, figs . 12-14. PERCH-N IELSEN Descri ption: Thi s form ha s an elliptical 1969a, p. 65 , pl. 5, figs. 1-3; PERCH· rim constructed of strong ly imbricate ele- NIELSEN, 1969b, p. 327, pl. 35, figs. 1-6.

PLATES Figure s 1, 2. Thoracosphaera multiperforara n. sp. la. Cro ss-polarized light , x3250; Sample CN-14 lb . Transmitted light , x3250; Sample CN-14 2. Electron micrograph, xl8,800, Sample CN-7 Figure 3. Thoracosphaera cf. T. im perforata Kamptn er ; Sample CN-1 Cross-polarized light , x3250 Figure 4. Micula decussata decussata Vek shina ; Sample CN-100 Phase-contrast, x3250 Figure 5. Coccolithus orbiculatus n . sp .; Sam ple CN-1 Sa. Cross-polarized light, x3250 Sb. Transmitted light , x3250 Figure 6. Coccolithus cf. C. orbiculatus; Sa mple CN-78 6a. Cross-polarized light , x3250 6b . Transmitted light , x3250 No. 1 Midway Calcareous Nannoplankton 33

1a 1b 3

s. Sb 6b

PLATE 8 Vol. 19 34 Tulane Studies in Geology and Paleontology

Description: This elliptical coccolith has bars , which are symmetrical with the axes . a low rim composed of a distal set of 30 to of the basal disc 35 elements, which show a strong dextral imbrication. Underlying these elements is EIFFELLITHUS TURRISEIFFELI (Deflandre) Reinhardt a set of approximately 45 rectangular basal Plate 9, figure 3 elements , which may partially close the DE large central opening. The central opening Zygolithus turris eiffeli DEFLANDRE in , 1954, p. 149, fig. 65; is spanned by a transverse bar composed LFLANDRE and FERT meet and form a pl. 13, figs. 15, 16. of elongate laths that elliptica VERKSHINA , 1959, p. The bar is highly arched and Rhabdosphaera short stem. 74, pl. 1, fig. 10; pl. 2, fig s, 14 a, b. rises above the distal rim when viewed turriseiffeli DEFLANDRE , 1959, the Zygrhablithus from the side. In the light microscope p. 135. MANIVIT , 1969, p . 191, pl. 1, fig. 1. crossbar may appear sigmoida l in shape. Zygrahablithus ? turriseiffeli (Deflandre). Size: Maximum length 8 microns. BRAMLETTE and MARTINI , 1964, p. 304, Occurrence: This species has been re pl. 3, figs. 18-21; pl. 4, figs. 1, 2. ported from the Paleocene of California, Eiffellithus turriseiffeli (Defl a ndre ). REIN , 1968, p. 26, Alabama, Denmark, and France and was HARDT, 1965 , p . 32. GARTNER ; pl. 3, fig. 13. THIERSTEIN, found in the Pine Barren and McBryde pl. 2, figs. 22-23 1971, p . 475, pl. 7, figs. 9-11. members of the Clayton Formation, the (Deflandre) . STO of the Porters Clinorhabdus turriseiffeli Matthews Landing Member VER , 1966, p. 138, pl. 3, fig . 9. Creek Clay, and in the Porters Creek. Description: This rhabdolith has the el liptical disc composed of 60 to 80 dextrally imbricate elements. The rim is exte nded Family RHABDOSPHAERACEAE distally. The central area may be partly or Lemmerman, 1903 completely covered. The X-shaped cross Definition: Rhabdoliths with a circular bars span the central area and may be basal plate composed of three or more cy symmetrical but not aligned with the axes cles of radial elements, and a distally tap of the basal disc. A hollow stem surmo unts ering stem. the centers of the cross bars. Size: Maximum length 8 microns. Genus EIFFELLITHUS Reinhardt, 1965 Occurrence: This species is com mon in Type species: Zygolithus turriseiffeli (De the Cretaceous and was found in the Pine flandre) Reinhardt, 1965 Barren Member of the Clayton Formation. Definition: Rhabdolith with the basal disc constructed of a single cycle of imbri Genus PREDISCOSPHAERA Vekshina cate elements that form a distally expand 1959 ing rim. The central area is usually open Type species : Prediscosphaera decorata Vek and is spanned by two intersecting cross shina , 1959

PLATE9 CN-11 Figure 1. Cribrosphaerella ehrenbergii Arkhangelsky; Sample la. Cross-polarized light, x3250 lb. Transmitted light, x3250 le. Interference-contrast, x3250 Figure 2. Prediscosphaera cretacea (Arkhangelsky) Gartner ; Sample CN-10 2a. Cross-polarized light , x3250, 45'' to polarizer 2b. Transmitted light, x3250 2c. Interference-contrast, x3250 CN-7 Figure 3. Eiffellithus turriseiffeli (Deflandre) Reinhardt; Sample 3a . Cross-polarized light, x3250 3b . Transmitted light, x3250 3c. Phase-contrast, x3250 3d. Interference-contrast, x3250 No. 1 Midway Calcareous Nannop lankton 35

1 a 1b 1c

2a 2b 2c

3a 3b

PLATE9 36 Tulane Studies in Geology and Paleontology Vol. 19

Definition: Rhabdoliths with a basal disc Family PRINSIACEAE constructed of two cycles of elements sepa Hay and Mohler, 1967 rated bya groove. The open central area is Genus PRINSIUS Hay and Mohler, 1967 spanned by two cross bars that intersect at Type species: Coccolithus bisulcus Stradner, the center and are surmounted by a stem . 1963 Definition : Elliptical placoliths, with PREDISCOSPHAERACRETACEA simple, solidly constructed distal shield; in (Arkhangelsky) Gartner terference figure between crossed polariz Plate 9, figure 2 ers dextrogyre; proximal shield bright, dis Coccolithophora cretacea ARKHANGELSKY, tal shield somewhat fainter. 1912, p. 410, pl. 6,figs . 12, 13. Rhabdolithus intercisus DEFLANDRE in DE FLANDRE and FERT, 1954, p. 159, p. 13, PRINSIUSDIMORPHOSUS (Perch-Nielsen) figs. 12, 13; text figs. 91-92. Plate 5, figure 1-3 Discolithus cretaceus (Arkhangelsky). GORKA, Biscutum? dimorphosum PERCH-NIELSEN, 1957, p. 251, pl. 2, fig. 11. BLACK and 1969a, p. 57, pl. 4, figs. 6-12; PERCH. BARNES , 1959, p. 326, pl. 11, figs. 1, 2. NIELSEN, 1969b, p. 318, pl. 32, figs. l-3a. Prediscosphaera decorata VEKSHINA, 1959, p. Prinsius dimorphosus (Perch-Nielsen). PERCH. 73, p. 1, figs. 8, 9; pl. 2, figs. 13a. NIELSEN, 1977, p. 794, pl. 30, figs. 10-13. Zygrhablithus intercisus (Deflandre). DE FLANDRE , 1959, p. 136, pl. 1, figs. 5-20. Description: The distal shield of this Deflandrius cretaceus (Arkhangelsky) . BRAM small elliptical to rounded placolith is com LETTE and MARTINI, 1964, p. 301, pl. 2, posed of 8-12 flattened trapezoidal ele figs. 11, 12. ments. A second cycle of elements is pre Deflandrius intercisus (Deflandre). BRAM- sent near the center. These are elongate d LETTE and MARTINI, 1964, p. 301, pl. 2, and inclined dextrally. The central ope n figs. 13-16. ing is small occupying only about one-te nth Prediscosphaera cretacea (Arkhangelsky). of the shield. The proximal shield is much GARTNER, 1968, p. 19, pl. 2, figs. 10-14; pl. 3, smaller and is composed of a single cyc le of fig. 8. THIERSTEIN, 1971, p. 479, pl. 7, fig. 7. elements equal in number to those in the Description : This form has a broadly el- distal shield. liptical to subcircular basal disc consisting Discussion: This species differs fro of two cycles of approximately 16 trapezoi Prinsius martinii in having few elements dal elements. The proximal cycle is smaller in lacking the central granular elements than the distal. The central area is span and in being less elliptical. ned by X-shaped cross bars, which consist Size: Maximum diameter 4 microns. of a proximal and distal set of bars that Occurrence: Representatives of have a square or rounded hole at the inter species were found in samples CN-1 an section. CN -100 from the McBryde Member ofth Size : Maximum diameter 7 microns. Clayton Formation. Occurrence: This species is common in the Cretaceous and was found in the Pine PRINSIUSMARTINII (Perch-Nie lsen) Haq Barren Member of the Clayton Formation. Plate 10, figures 1-4

PLATEl0 Figures 1-4. Prinsius martinii Perch-Nielsen la. Cross-polarized light, x3250, 40° to polarizer; Sample CN-26 lb. Phase-contrast, x3250; Sample CN-26 2. Cross-polarized light, x3250; Sample CN-26 3. Electron micrograph, xl8,300, Sample CN-32, distal view 4. E lectron micrograph, xl8,300, Sample CN-32, distal view Figure 5. Markalius reinhardtii Perch-Nielsen; Sample CN-14 5a. Cross-polarized light, x3250, low focus 5b. Cross-polarized light, x3250, high focus 5c. Phase-contrast, x3250 No. 1 Midway Calcareous Nannoplankton 37

1a 1b 2

Sb Sc

PLATElO 38 Tulane Studies in Geology and Paleontology Vol. 19

Ericsonia ? martinii PERCH -NIELSEN , 1969a , light microscope these forms appear p. 61, pl. 4 , figs. 13, 14; PERCH-NIELSEN , mainly as elliptical rings . 1969b, p. 324 , pl. 32, fig s. 3b , 5, 6, 7. HAQ , Discussion : These forms are very similar 1971, p. 18 , pl.5 , fig~ 1,5,6 , 7, 10. in size, shape, and number of elements to Prinsius martinii (Perch-Niel sen ). PERCH Prinsius martinii and probably represent NIELSEN , 1977, p. 794, pl. 30 , fig. 3. partially dissolved or poorly preserved Description: The distal shield of this specimens of that species . small elliptical placolith is composed of 15 Size: Maximum length 4 microns . to 25 flattened trapezoidal elements. A sec Occurrence : Representatives of this ond cycle of elements is present near the form were found in 8 of the 10 samples center. These elements are triangular in from the Pine Barren Member of the shape and are inclined dextrally. Inside of Clayton Formation. and immediately adjacent to this second set of elements is a set of irregular ele Genus TOWEIUS Hay and Mohler, 1967 ments that may overlay the second set and Type species: Toweius crat iculus Hay and extend into the central opening. The cen Mohler, 1967 be filled or partially filled tral opening may Definition : Circular to subcircular with irregular granular elements, which placoliths whose shields are constructed of may or may not be part of the previous ir petaloid or trapezoidal elements , whic h regu lar elements. are nonimbricate to slightly imbricate. The Perch-Nielsen described Discussion: central area contains a reticulate grill. this species as having columnar elements that meet in the middle along the major axis of the ellipse. Some of the specimens TOWEIUSPETALOSUS Ellis and Lohman seen in the Alabama Midway do not have Plate 6, figure 4 central elements meeting , probab ly due to Toweius petalosus ELLIS and LOHMAN, 1973, partial solution. p. 107 , pl. 1, figs. 1-11. Size: Maximum length 3 microns. Description: This small elliptical Occurrence: Representatives of this placolith has a distal shield composed of9 species were found in all three samples of to 17 petaloid plates or elements, which the McBryde Member of the Clayton For originate in the central area and exten mation, and in the Matthews Landing outwards showing a slight sinistra l i mbri Member of the Porters Creek Clay. cation . The petaloid plates expand i width towards the outer edge of the dis PRINSIUScf. PRINSIUSMARTINI! shield. These plates extend beyond th Plate 3, figures 3, 4 outer edge of the distal shield giving th Plate 6, figure 5 palcolith a crown -like appearance . Th Description: This elliptical placolith has proximal shield is smaller and is compos a distal shield of 20 to 25 elements. The of what appear to be two cycles of re lativ central area may be open or partially ly flat elements that are approximate ly t closed by elongate elements. Under the same in number as the distal shield .

PLATE 11 Figures 1, 2. Cruciplacolithus tenuis var . b ; Sample CN-78 la. Cross-polarized light, x3250, 70° to polarizer lb. Transmitted light, x3250 le . Interference-contrast, x3250 2. Electron micrograph, x9200, distal view Figure 3. Cruciplacolithus tenuis var. c; Sample CN-18 3a . Cross-polarized light , x3250 3b. Transmitted light , x3250 Figure 4. Cruciplacolithus tenuis var . a; S ample CN-14 4a. Cross-polarized light, x3250 4b . Phase-contrast, x3250 No . 1 Midway Calcareous Nannoplankton 39

1a 1b 1c

2 3b

PLATE 11 40 Tulane Studies in Geology and Paleontology Vol. 19

Si ze: Maximum length 3 microns. talith varies from slightly rounded to angu Occurrence: This species was reported lar. from the Clayton Formation and Porters Size: Maximum diameter 7 microns. Creek Clay by Ellis and Lohman and was Occurrence: This species is present in found in the Pine Barren Member of the Cretaceous through Holocene sediments, Clayton Formation in the present study . and was found in the Matthews Landing Member of the Porters Creek Clay . Family BRAARUDOSPHAERACEAE Deflandre, 1947 BRAARUDOSPHAERA TURBINEA Stradner Genus BRAARUDOSPHAERA Plate 3 , figure 5 Deflandre, 1947 Braarudosphaera turbinea STRADNER, 1963, Type species: Braarudosphaera bigelowi (Gran p. 10, pl. 6, fig. 8. and Braarud) Deflandre , 1947. Description: This pentalith consists of Definition: Pentaliths consisting of five five triangular elements, which are sinist quadrangular segments or elements whose rally imbricate. The outer edge of the over outer edges are straight or slightly curved. lapping side tends to be slightly pointed. The elements meet at straight sutures , Size : Maximum diameter 7 microns . which run from the center to the angles or Occurrence: This species was origina lly the outer edges. The elements have no reported from the Paleocene of Austr ia perforations or depressions. and was found in the Pine Barren Membe r of the Clayton Formation.

BRAARUDOSPHAERABIGELOWII Family PONTOSPHAERACEAE (Gran and Braarud) Deflandre Lemmermann, 1903 Plate 2, figure 4 Genus DISCOLITHINA Pontosphaera bigelowi GRAN and BRAARUD, Loeblich and Tappan, 1963 1935, p. 389, text fig. 67. Type species: Discolithus vigintiforatus Braarudosphaera bigelowi (Gran and Braarud). Ka mptner, 1948 . DEFLANDRE, 1947 , p . 439, figs . 1-5. DE FLANDRE , 1950, p. 1156, text figs. 1-4. Definition: Elliptical disc with or wit hout BRAMLETTE and RIEDEL, 1954, p . 393, pl. distinct rim, generally perforated. 38, figs. la, b . BRAMLETTE and SULLI VAN , 1961, p. 153, pl. 8, figs . la, b , 2-5. SUL DISCOLITHINA VERSA LIVAN, 1964, p. 188 , pl. 8, figs . la, b . HAY (Bramlette and Sullivan), n. comb. and MOHLER, 1967, p. 1535 , pl. 202 , figs. 12 , Plate 2, figure 3 16, 20. PERCH -NIELSEN , 1971b, p. 942 , fig. 1. BYBELL and GARTNER, 1972, p . 323, pl. Discolithus versa BRAMLETTE and SULLI 1, figs. 1, 2. VAN, 1961 , p . 144, pl. 3, fig. 16 . SULLIVAN 1964, p. 183, pl. 4, fig. 11 . SULLIVAN, 1965, p. Description : These pentaliths are com 35, pl. 5 , figs. 8 , 9. posed of five elements separated by dis Pontosphaera versa (Bramlette and Sullivan tinctive sutures that run from the center to SHERWOOD, 1974, p. 31, pl. 5, figs. 1 , 2; pl. 4, the outer edges. The periphery of the pen- fig. 10.

PLATE 12 Figures 1, 2. Neococcolithes protenus (Bramlette and Sullivan) Hay and Mohler; Samp CN-78 la. Cross -polarized light , x3250 lb . Transmitted light , x3250 le. Phase-contrast, x3250 2. Electron micrograph, x9500, distal view Figures 3, 4. Heliorthus concinnus (Martini) Hay and Mohler; Sample CN -78 3a. Cross-polarized light , x3250 3b. Transmitted light, x3250 3c. Phase-contrast , x3250 4. Electron micrograph, x18,800 No . 1 Midway Calcareous Nannoplankton 41

1a 1 b 1c

PLATE 12 42 Tulane Studies in Geology and Paleontology Vol. 19

Description : This elliptical discolith has a Occurrence : This species is common in distinct rim that encloses the base plate . the Cretaceous and was found in the Pine The base plate contains a sigmoidal slit, Ba rren Member of the Clayton Formation . which appears widest at each end. Size: Maximum length 7 microns . Family THORACOSPHAERACEA Occurrence : This species is present from Schiller, 1930 the Paleocene through the Oligocene and Genus THORACOSPHAERA was found in the Matthews Landing Mem Kamptner , 1927 ber of the Porters Creek Clay. Type species: Thoracosphaera pelagica Kamptner , 1927. Family SYRACOSPHAERACEAE Definition : Coccolithophorids with a Lemmermann, 1903 spherical test composed of regular to ir Genus CRIBROSPHAERELLA regularly-shaped polygonal elements of Deflandre, 1952 calcite . Type species : Cribosphaera ehrenbergi Ar khangelsky, 1912. THORACOSPHAERAMULTIPERF0RATA , n. sp. Definition: Elliptical disc with a cribrate Plate 7, figures 3, 4, 5; central plate and a rim of two or three Plate 8, figures 1, 2 tiers . Each tier is constructed of a single Description : These coccolithophorids cycle of elements, which meet along ir are composed of small elongate but irregu regular sutures. The central plate may or lar elements which are arranged radially may not have perforations. around small perforations. Smaller more equidimensional elements are present CRIBROSPHAERELLAEHRENBERG II where the elongate elements meet. In (Arkhangelsky) Deflandre cross polarized light the elemj:!nts appear Plate 9, figure 1 as four very elongate units framing the Cribrosphaera ehrenbergi ARKHANGELSKY, perforations. 1912, p. 412, pl. 6, fig. 19. Size : Maximum observed length of ele Cribrosphaerella ehrenbergi (Arkhangelsky). ment - 1 micron. DEFLANDRE, 1952, p. 111, text fig. 54a (non Holotype: USNM 388225 - CN-7A 296 (1. 54b). GORKA, 1957, p. 260, pl. 4, fig. 12. x 9.4)(Plate 7, figure 3) GARTNER, 1968, p. 40, pl. 1, figs. 14-15; pl. 3, Paratypes: CN-14-31 (20.4 x 12. 7)(Plate 7 fig. 2; pl. 6, fig. 7; pl. 12, fig. 2; pl.15, fig. 11. figure 4). SEM CN-7-5 (Plate 7, figure 5) CEPEK, 1970, p. 239, pl. 22, figs . 1, 2; pl. 26, Occurrence: Representatives of t · fig.I. species were found in the Pine Barren a Description: This form has an elliptical McBryde members of the Clayton For disc with a rim of two tiers, each con tion , and the Matthews Landing Mem structed of a single cycle of elements . The of the Porters Creek Clay . central area is covered by a complex perfo rated plate . THORAC0SPHAERASAXEA Stradner Size : Maximum length 7 microns. Plate 7, figure 2

PLATE 13 Figure 1. Coccolithus sp.; Sample CN-26 la . Cross-polarized light, x3250 lb. Cross-polarized light, x3250, 45° to polarizer le . Phase-contrast, x3250 Figures 2-5. Heliothus denticulatus Perch-Nielsen 2a. Cross-polarized light, x3250; Sample CN-14 2b . Phase-contrast, x3250 ; SampleCN-14 3. Electron micrograph, x19,200, Sample CN-14, proximal view 4a. Cross-polarized light , x3250; Sample CN-10 4b. Phase-contrast , x3250; Sample CN-10 5. Electron micrograph , x8000, Sample CN-14 , distal view 43 No. 1 Midway Calcareous Nannoplankton

1a 1b 1c

2 a 2b

PLATE 13 44 Tulane Studies in Geology and Paleontology Vol. 19

Thoraosphaera sp. BRAMLETTE and RIEDEL, the Clayton Formation, and the Matthews 1954, p. 393, pl. 38, fig. 5. Landing Member of the Porters Creek Thoracosphaera saxea STRADNER, 1961 , p. 84, Clay . text fig . 71. COHEN, 1964, p. 248, pl. 5, figs 6 a-e; pl. 6, fig . 6. HAY and MOHLER, 1967, p. Genera INCERTAE SEDIS 1534, pl. 203, fig. 5. SACHS and SKINNER , Genus MICULA Vekshina 1973, p. 147, pl. 5, figs. 10-12. , 1959 Type species: Micula decussata Vekshina, Description: This form consists of small 1959 irregular imperforate elements that form a spherical test. The contacts between the Definition : Cube, with concave or plane elements may appear crenulated . faces and constructed of calcite laminae Size: Maximum observed length of ele that are not crystallographically continu ment - 1 micron. ous . Occurrence: This species is found in Cre taceous to Holocene sediments and was MICULA DECUSSATA DECUSSATA Vekshina found in the Pine Barren and McBryde Plate 8, figure 4 members of the Clayton Formation, and Micula decussata VEKSHINA, 1959, p. 71, pl. 1, the Matthews Landing Member of the Por fig. 6; pl. 2, fig. 11. ters Creek Clay. Discoaster staurophorus GARDET, 1955, p. 534, pl. 10, fig. 96. Trochoaster staurophorus THORACOSPHAERA cf. THORACOSPHAERA (Gardet). STRA D NER , 1959, p. 480, figs . 49-50. MARTI NI, IMPERFORATA Kamptner 1960, p. 82, pl. 10, fig. 37. Plate 7, figure 1; Plate 8, figure 3 Nannotetraster staurophorus (Gardet). MA R cf. Thoracosphaera imperforata KAMPTNER, TINI and STRADNER , 1960, p. 266, fig. 1. 1955, p. 37, pl. 8, fig. 98. STRADNER and PAPP, 1961, p. 101, pl. 31, Thoracosphaera cf. T. imperforata Kamptner. figs. 2-4. BRAMLETTE and MARTINI, 1964, p. 305, Micula staurophora (Gardet) STRADNER. 19 63, pl. 5, figs. 1, 2. p. 179 , pl. 4, fig. 12a. BRAMLETTE a nd MARTINI, 1964, p. 318, pl. 6, fig. 7-11. Description: These large irregular ele Micula decussata Vekshina. GARTNER, 1 ments form a mosaic of interlocking units . (partim), p. 47, pl. 2 , figs. 5-8; pl. 4, fig. 17; pl. The size of the elements is fairly uniform 9, fig. 18 ; pl. 14 , fig. 13; pl. 18, fig. 7; pl. 20, and the edges appear smooth. Under fig.15. cross -polarized light the elements appear Micula decussata decussata Vekshina. B UR as larger somewhat elongated units , sur KRY, 1969, p. 67, pl. 40, figs. 5, 6. rounded by a dark line. Description: This cube has conc av Discussion: The elements of this species faces and orthogonal or slightly exte nde are larger and seem to have smoother corners. The concave faces make the fo edges than those of Thoacosphaera saxea. appear to be a four-rayed star under t Size: Maximum width of element - 2 light microscope. microns. Size: Maximum width 4 microns . Occurrence: This species was described Occurrence: This species is common· from the Cretaceous and Paleocene in var the Cretaceous and was found in the Pin ious worldwide localities and was found in Barren and McBryde members of t the Pine Barren and McBryde members of Clayton Formation .

PLATE 14 Figures 1-5. Zygodiscus sigmoides Bramlette and Sullivan 1. Electron micrograph, x9500, Sample CN-7, distal view 2. Electron micrograph , x9300, Sample CN-7, distal view 3a. Cross-polarized light, x3250; Sample CN-78 3b . Transmitted light, x3250; Sample CN-78 4. Electron micrograph, x9200, Sample CN-7, proximal view 5a . Cross-polarized light , x3250; Sample CN -7 5b . Transmitted light, x3250; Sample CN -7 No. 1 Midway Calcareous Nannoplankton 45

5a 5b

PLATE 14 46 Tulane Studies in Geology and Paleontology Vol. 19

IX. REFERENCES Paleont. Contr. , Art. 51 (Protita 2), p . 1-79, 40 pis. ARKHANGELSKY , A. D., Verkhnemelovyy a BYBELL , LAUREL M ., a nd STEFAN GART otolozheniya vostoka evropeyskoy Ros si NER , JR., 1972, Provincialism among mid [Upper Cretaceous deposits of east European Eocene calcareous nannofo ssils: Micropaleon Russia]: Mater. Geo!. Russi. , vol. 25, 631 p., 10 tology , vol. 18 , no . 3, p. 319-336 , 5 pi s., 1 text pis. fig. BERGGREN, WILLIAM A ., 1965, Some prob CEPEK , PAVEL, 1970, Zur Vertikalverbreitung lems of Paleocene-Lower Eocene planktonic von Coccolithen -Arten in der Oberkreide foraminiferal correlations: Micropaleontol NW-Deutschlands: Geo!. Jb ., vol. 88, p. 235- ogy, vol.11, no. 3, p. 278-300, 1 pl. , 12text-figs. 264. BLACK , MAURICE, 1967, New names for some CEPEK, PAVEL, WILLIAM W. HAY , BRUCE coccolith taxa: Proc . Geo!. Soc. London, no. A. MASTERS and THOMAS R. WORSLEY , 1640, p. 139-145. 1968, Calcareous plankton in samples from BLACK, MAURICE, and BARBARA field trip stops , in Facies changes in the Selma BARNES, 1959, The structure of coccoliths Group in Central and Eastern Alabama: from the English chalk: Geo!. Mag ., vol. 96, p. Guidebook for Sixth Annual Field Trip, 321-328, pis. 8-12. Alabama Geo!. Soc ., p. 33-40. BLOW, WALTER H., 1969, Late middle Eocene CHRISTENSEN , T ., 1962, Klasse Hap to Recent planktonic foraminiferal biostratig tophyceae: Botanik Systematisk Botanik, vol. raphy: in P . BRONNIMAN, and H. H . RENZ 2, p. 72-74. (ed.), Proc. First International Conference on COHEN , CAREL L . D., 1964., Coccolith Planktonic Microfossils, Geneva, 1967 , vol. 1 , ophorids from two Caribbean deep -sea cores: p. 199-422, 54 pis. , 43 figs. Micropaleontology, vol. 10 , no. 2 , p. 231-250, BOLL!, HANS M ., 1957 , The genera pis. 1-6 . Globigerina and Globorotalia in the DEFLANDRE, GEORGES, 1947, Braarudo Paleocene-Lower Eocene Lizard Springs sphaera nov. gen. , type d'une famille nouvelle Formation of Trinidad, B .W.1.: U.S. Natl. de Coccolithophorides actuels a elements Mus., Bull. 215, p . 61-81, pis. 15-20. composites: C. R. Acad. Sci. (Paris), vol. 225, BORNHAUSER, MAX , 1947, Marine sedimen p. 439-441 , 5 figs. tary cycles of Tertiary in Mississippi Embay DEFLANDRE , GEORGES , 1950, Observations ment and central Gulf Coast area: Amer. sur les Coccolithophorides , a propos d'un Assoc. Petrol. Geo!., Bull ., vol. 31, p. 698-712. nouveau type de Braarudosphaeride , Mic BRAARUD, TRYGVE, GEORGES DE- rantholithus, a elements clastiques: C. R. FLANDRE, PER HALLDAL, and ERWIN Acad . Sci . (Paris), vol. 231, p. 1156-1158, 11 KAMPTNER, 1955, Terminology, nomencla figs. ture , and systematics of the Coc DEFLANDRE , GEORGES, 1952; Classe des colithophoridae: Micropaleontology, vol. 1 , Coccolithophorides: In GRASSE , P. P . (ed.1, no. 2, p. 157-159. Traite de Zoologie , vol. 1 , pt. 1 , p. 439-470, 25 BRAMLETTE, M . N ., and ERLEND MAR text-figs. TINI, 1964 , The great change in the calcare DEFLANDRE , GEORGES , 1959, Sur les nan · ous nannoplankton fossils between the Maes nofossiles calcaires et leur systematiq ue: Rev trichtian and Danian : Micropaleontology , vol. Miropaleont., vol. 2, p. 127-152, 4 pis. 10, no . 3, p. 291-322, 7 pis ., 1 text-fig. DEFLANDRE , GEORGES , and CHARLES BRAMLETTE, M. N., and WILLIAM R. FERT , 1954, Observations sur les C RIEDEL , 1954, Stratigraphic value of discoa s colithophorides actuels et fossiles en micro-: ters and some other microfossils related to Re scopie ordinaire et electronique: Ann cent Coccolithophores: Jour . Paleont., vol. 28 , Paleont. , vol. 40, p. 115-176 , 15 pis ., 127 text no. 4 , p . 385-403, pis. 38 , 39, 3 text-figs. figs. BRAMLETTE , M. N. , and FRANK R. SULLI EHRENBERG , CHRISTIAN G. , 1836, Bemer VAN, 1961 , Coccolithophorids and related kungen uber feste mikroskop ische anor nannplankton of the Early Tertiary in Califor ganische Formen in den erdigen und derbe nia: Micropaleontology , vol. 7, no . 2, p. 129- Mineralien : Bex . Kon . Akad . Wiss . Berli 188, 14 pis. , 1 text-fig. Ber. , p. 84-85. .. BRONNIMANN , P. , and HERBERT STRAD EHRENBERG, CHRISTIAN G., 1840, Uber NER, 1960 , Die Foraminiferen - und Discoas Bildung der Kreidefelsen und 'teriden - zonen von Kuba und ihre interkon Kreidemergels

spec ies, a Paleocene calcareous nannofossil Paleocene-early Eocene correlations: Jour. from Alaba ma: Tulane Stud. Geo!. Paleont., Paleont., vol. 41, no. 6, p. 1505-1541, pis. 196- vol. 10, no. 2, p. 107-110, 1 pl. 206, 5 figs. GARDE T, M., 1955, Contribution a L'Etude des HAY, WILLIAM W., HANS P. MOHLER, Coccolithes des Terrains Neogenes de PETER H. ROTH, RONALD R. SCHMIDT, L'Alge rie : Puhl. Serv. Carte Geo!. and JOSEPH E. BOUDREAUX, 1967, Cal AL'Alg erie, (Nouv. Ser) Bull., 5, p. 477-550, 11 careous nannoplankton zonation of the pls., 1 fig. Cenozoic of the Gulf Coast and Caribbean GARTNE R , STEFAN, JR., 1967, Nannofossil Antillean area, and transoceanic correlation: species related to Cyclococcolithu_s leptoporus Gulf Coast Assoc. Geo!. Soc., Trans., vol. 17, (Murray and Blackman): Umv. Kansas p. 428-480, pis . 1-13. Paleont. Contr., Paper 28, p. 1-4, 2 pls. HAY, WILLIAM W., HANS P. MOHLER, and GARTNER, STE FAN, JR., 1968, Coccoliths and MARYE. WADE, 1966, Calcareous nannofos re lated ca lcareo us nannofossils from Upper sils from Nal'chik (Northwest Caucasus): Ec Cretaceou s deposits of Texas and Arkansas: logae Geo!. Helv ., vol. 59, no. 1, p. 379-399, Univ. Kan sas Paleont. Contr., Ser. No. 48, pis . 1-13. (Pro tista Art. 1), vol. 1, p. 1-56, 28 pls., 5 text HAY, WILLIAM W., and KENNETH M. figs. TOWE, 1962, Electron microscopic examina GARTNER, STEF AN, JR ., 1971, Calcareous tion of some coccoliths from Donzacq (Fr nan nofossils from the JOIDES Blake Palteau ance) : Eclogae Geo!. Helv., vol. 55, p. 497-517, core s and re vision of Paleogene nannofossil pis. 1-10, 2 figs. zonat ion: Tu lane Stud. Geo!. Paleont., vol. 8, HUXLEY, THOMAS H., 1868, On some or no. 3, p. 101-121, 5 pis., 5 text-figs. ganisms living at great depths in the North At GOHRBANDT, K., 1963, Zur Gliederung des lantic Ocean: Royal Micros. Soc., Quart. Palao gen im He lvetikum n6rdlich Salzburg Jour., (Ser . 2) vol. 8, p. 203-212, pl. 4. nach plankto nischen Foraminifern: Mitt. KAMPTNER, ERWIN, 1927, Beitrag zur Geo!. Ges. Wien., vol. 56, no. 1, p. 1-116, pls . 1- Kenntnis adriatischer Coccolithophoriden: 11, 7 te xt-figs. Arch. Protistenk., vol. 58, p. 173-184, 6 figs. GORKA, HANNA, 1957, Les Coc- KAMPTNER, ERWIN, 1928, Uber das System colithophorides du maestrichtien superieur de und die Phylogenie der Kalkflagellaten: Arch. Pologn e: Acta Pa laeon t. Polonica, vol. 2, p. Protistenk., vol. 64, p. 19-43. 235-284, 5 pls. KAMPTNER, ERWIN, 1948, Coccolithen aus GRAN, H. H., and TRYGVE BRAARUD, 1935, dem Torton des Inneralpinen Wiener Bec A qualita tive study of the phytoplankton in the kens: SitzBer. Osterr. Akad. Wiss., Math. Bay of Fu ndy and the Gulf of Maine: Biol. Nat. Kl., v. 157, p. 1-16, 2 pis. Board Can ada, J our ., vol. 1, p. 279-467, 69 KAMPTNER, ERWIN, 1955, Fossile Coccolithi figs. neen-Skelettreste aus Insulinde: Eine mik HALLDAL, PER, an d JOA R MARKALI, 1954, ropalaontologische Untersuchung: K. Nederl. Morphology and microstr ucture of coccoliths Akad . Wet. Afd. Natuurk. vehr., (Ser. 2) vol. studied in th e elect ro n microscope: Observa 50, no. 2, p. 1-87, pis. 1-9. tions on Anthosphaera robusta and Calyptros LAMOUREAUX, PHILIP E., and L. D. TOUL phaera papill ifera: Nytt Mag. Bot., vol. 2, p . MIN, 1953, The Midway and Wilcox Groups in 117-119,2 pis. central and western Alabama: Guidebook, HAQ, U. Z. B. , 1971, Pa leogene calcareous nan Tenth Field Trip, Mississippi Geo!. Soc., p. 5- noflora, Par t I: the Pa leo cene of West-Central 29. Persia and th e Upper Paleoce ne-Eocene of LEMMERMANN, E. N., 1903, Phytoplankton West Paki stan : Stockho lm Contrib. Geo!., vol. des Meeres, II Beitrag: Naturw. Bremen 25, p. 1-56, 14 pis., 2 figs. Abh., vol.17, p. 341-418. HAY, WILLIAM W., 1960, The Cretaceous-Ter LOEBLICH, ALFRED R., JR.., and HELEN tiary_boundar y in the Ta mpico Embayment, TAPPAN, 1957, Plantktonic foraminifera of Mexico. Int. Geo!. Cong r., Rep. 21st Sess., Paleocene and early Eocene age from the orden, pt. 5, p. 70-77. Gulf and Atlantic Coastal Plans: U.S. Natl. H~~ WILLIAM W., and HANS P. MOHLER, Mus., Bull. 215, p. 173-198, pis . 4-64. 5, Zur Ver br eitung des Nannoplanktons LOEBLICH, ALFRED R. , JR., and HELEN ';' Prolil der Grossen Sch liere: Ver. Schweiz. TAPPAN, 1963, Type fixation and validation f, elrol. Geo!. Ing., Bull., vol. 31, p. 132-134, 1 of certain calcareous nannoplankton genera: ·~- Biol. Soc. Washington, Proc., vol. 76, p. 191- H~~t ~LLIAM W., and HANS P. MOHLER, 196. T '. alcarous nannopla nkton from Early MACNEIL, F . STEARNS, 1946, Geologic map ertiary rock s at Pont La ba u , France, and of the Tertiary formations of Alabama: U.S. 48 Tulane Studies in Geology and Paleontology

Geo!. Survey Oil & Gas Invest. Prelim . Map PERCH-NIELSEN , KATHARINA No . 45. , 1969b, E tronenmikro skopi sche U ntersuchungen MANIVIT , HELEN , 1965, Nannofossils cal Coccolithophoriden der Dan-Scholle caires de l 'Albo-Aptien ¥ : Rev. Micropal eont., Katharinenhof (Fehmarn ): N. Jb. vol. 8, p. 189-201, pis. 1-2. Palaont ., Abh MARTINI ., vol. 132, p. 317-332, pis. , ERLEND , 1959, Der stratig 5 figs. raphische Wert von Nannofossilien im PERCH -NIELSEN , nordwestdeutschen Tertiar KATHARINA , 1971a, : Erdol. u . Kohle , eolith terminology : in A. FARINACCI, vol. 12, p. 137-140 (ed. , 1 fig. Proc. II Plank . Conf ., Roma MARTINI , ERLEND , 1970, vol. 2, , 1961, Nanhoplankton aus 1348-1359, 17 figs. dem Tertiar und der obersten Kreide von PERCH-NIELSEN , KATHARINA , 1971b, SW-Frankreich : Senckenb . Lethaea , vol. 42, chsicht Tertiarer Coccolithen: no . 1-2, p. 1-32 i , pis. 1-5, 3 text-figs . FARINACCI , A. (ed MARTINI , .), Proc . II Plank. Cont. ERLEND , 1964, Die Coc- Roma , 1970, p. colithophoriden der Dan-Scholle von 939-979, 2 pis., 22 figs. PERCH-NIELSEN , KATHARINA , 1977, Alb" Katharinenhof (Fehmarn ): N . Jb. Geo!. to Pleistocene Calcareous Nannofossils fro Palaont. Abh ., v. 121, p. 47-54, pis. 6-7. the western South Atlantic MARTINI , DSDP Leg 39: i , ERLEND , 1970, Standard P.R. SUPKO Paleogene Calcareous Nannoplankton Zona , K. PERCH -NIELSEN, et al. (ed.), Initial Reports of the Deep Sea Ori · tion : Nature , vol. 226, no. 5245, p . 560-561, 1 Project , vol. 39, p. 699-823, pis fig. . 1-50. RADOMSKI , A., 1968, Pozimy nannoplankto MARTINI , ERLEND, 1971, Standard Tertiary wapiennego w . Paleogenie Polskich and Quaternary calcareous nannoplankton Ka Zachodnich : Rocz . Pol. Tow. Geo!. vol. zonation: in A. FARINACCI 38, no , ( ed. ) Proc . II 4, p. 545-605, pis . 43-48, 3 figs. Plank. Conf ., Roma , 1970, vol. 2, p. 739-785, REINHARDT , PETER, 1964 , Einige Kalkflage pis. 1-4. laten-Gattungen MARTINI, ERLEND, and HERBERT (Coccolithophoriden , C colithineen ) aus STRADNER dem Mesozoikum Deutsch , 1960, Nannotetraster, eine lands : Deutsche Akad stratigraphische . Wiss. Berlin , Monats bedeutsame neue Discoas ber ., vol. 6, p. 749-759 teridengattung: Erdol-Z , 2 pis ., 8 text-figs. ., vol. 76, p. 266-269, REINHARDT , PETER 19 figs. , 1965, Neue Familien fur fossile Kalkflagellaten MURRAY , GEORGE (Coccolithophori , and V. H . BLACKMAN, den , Coccolithineen ): 1898, On the nature of the coccospheres and Deutsche Akad . Wiss. Berlin , Monatsber ., vol. 7, p. 30-40 , 6 figs., rhabdospheres : Roy Soc . London , Phil. pis. Trans ., vol. 190 (Ser. B), p. 427-441, pis . 15, 16. REINHARDT , PETER, 1966 , Zur Taxionomie MURRAY , GROVER E. , JR. , 1947, Cenozoic und Biostratigraphie der fossilen nannop deposits of Central Gulf Coastal Plain : Amer . lanktons aus dem Malm , der Kreide und dem Assoc. Petrol. Geo!. Bull ., vol. 31, p. 1825- Alttertiar Mitteleuropas 1850. : Freiberger Forsch., C 196 Palaontologie , p. 5-109 MURRAY , JOHN , 23 pis. , 29 figs. , and ALPHONSE F . RE SACHS, JULES B ., and HUBERT C NARD , 1891, Report on deep-sea deposits . SKIN NER , 1973, Calcareous nannofossils and late based on the specimens collected during the Pliocene-early Pleistocene biostratigraphy voyage of H . M. S. Challenger in the years 1872 Louisiana Continental Shelf : Tulane Stud. to 1876, in Report on the scientific results of Geo!. Paleont. , vol. 10, no. 3 , p. 113-162, 6 pis. the voyage of H .M.S . Challenger during the 6 figs. years 1872 to 1876 , pt. 3 , Deep-sea deposits . SAFFORD , J . M., 1864 525 p., , On the Cretaceous and 29 pis. 35 figs. superior formations of west Tennessee: NOEL , DENISE, 1965, Sur les coccolithes du American Jour . Jurrassique Europeen Sci., (2nd Ser. ) vol. 37, p. 360- et d'Afrique du Nord ; 372. Essai de classification des coccolithes fossiles : SCHILLER , JOSEF , 1930 Paris , Centre Nat. Rech , Coccolithineae : inL. . Sci ., 209 p., 29 pis. , RABENHORST , 74 figs Kryptogamen-Flora von . Deutschland , PERCH-NIELSEN Osterreich und der Schweiz., , KATHARINA , 1968, Der vol. 10, no . 2, Feinblau und die Klassifikation der Coc Ver!. Gesell ., Agt. , Leipzig Akad., p . 89-267, 137 figs. colithen aus dem Maastrichtien + figs. A-F. von SCHWARTZ, E. H. L. , 1894, Coccoliths: Ann. Danemark : Danske Vidensk . Selsk . Biol. Mag . Nat.Hist. , (Ser . 6) vol. 14, p. 341-346, 27 Skr ., vol. 16, no. 1 , p. 1-96, 32 pis., 42 figs. figs. PERCH-NIELSEN , KATHARINA , 1969a, Die SHERWOOD, RONALD W Coccolithen einiger danischer Maastrichtien ., 1974, Calcareous nannofossil systematics , paleoecology , nd und Danienlokalitaten : Medd . Dansk. Geo!. biostratigraphy of the middle Eocene W eches Foren ., Kobenhav, no. 19 , p. 51-68, 7 pis ., 1 Formation of Texas fig. : Tulane Stud. Geo!. Paleont .: vol.11 , no . 1, p. l-79,pls.1-12. Midway Calca reous Na nnopla nkton 49 No-1 IESS ER, W. G., 1983, P aleog ene ca lcareou s SUJKOWSKI , Z., 1931, Petrografj a kr edy S nan noplankto n biostratigraph y : Mississ ippi P olski, Kred a z gl ebokie go wierceni a w Lub l)ep t. Nat. Reso ur ces , Bur . Geo logy, Bull . linie w p orown aniu z kreda niektor ych inn ych 61 p., 37 figs., 15 tables. obszarow Pol ski. ( Etude petrographigue due 125 Cretace de Polo gne . La ser ie de Lublin e t s a sMI; H,-ElJG EN E A., ~886, ~ summar y of the comparai son avec la craie blanch e): Spraw . lithological a nd strab~aph 1cal features and l. In st. Geo!. , vol. 6 , p. 485-628, pis. 6-13 , 4 ubd ivisions of the Tertiar y of Alabama , in T. P o text -figs. ALDRICH, Preliminar y repor t on th e Ter H. , FRANK R. , 1964, Lower Tertiary tiary fossils of Alabama and Missi ssippi : SULLIVAN nnoplankton from the California coast Alabama Geo!. Sur vey , Bull . 1, p . 7-14. na ran ges . I, Paleocene : Univ . Calif . Pub!. Geo!. SMITH, EU GENE A. , 1892, On the phosphates , no . 3, p. 163-228, 12 pis., 2 figs. and marls of Alabama : Alabama Geo!. Sur Sci. , vol. 44 SULLIVAN , FRANK R. , 1965, Lower Tertiary vey, Bull. 2, 82 p . coast SMITH, EU GENE A., and L . C. JOHNSON, nannoplankton from the California , Eocene : Univ . Calif . Pub!. Geo!. 1887, Terti ary and Cretaceous strata of the ranges . II , p. 1-74, 11 pis., 2 figs. Tuscaloosa, Tombigbee , and Alabama rivers : Sci. , vol. 53 , HANS , R. , 1971, Tentative U.S. Geo!. Surve y, Bull . 43, 189 p. THIERSTEIN s nannoplankton SMITH, EU GENE A ., L . C. JOHNSON , and D. 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