mwen een weteoensbwaivicsten mew eationeeecrc hceehet ieee ee ns bee MARYLAND fe OmrcAlA SURVEY BOGEN BALTIMORE THE JOHNS HOPKINS PRESS 1901 nan ip ~The L. PRINTED BY The Fricdenwmald Company BALTIMORE, MD., U.S.A. MCZ LIBRARY Mist, i 4 QO; HARVAI cL) UNIVERSITY ‘COMMISSION JOHN WALTER SMITH, . } : ; : ‘ PRESIDENT. GOVERNOR OF MARYLAND, JOSHUA W. HERING, COMPTROLLER OF MARYLAND. DANIEL C. GILMAN, . : ‘ t EXECUTIVE OFFICER. PRESIDENT OF THE JOHNS HOPKINS UNIVERSITY. R. W. SILVESTER, . . : s . ; ? SECRETARY. PRESIDENT OF THE MARYLAND AGRICULTURAL COLLEGE. SCE RIMPIG STArE Wu. Buttock CLARK, ; ; : E : STATE GEOLOGIST. SUPERINTENDENT OF THE SURVEY. Epwarp B. MATHEWS, . : . ASSISTANT STATE GEOLOGIST. CHIEF OF THE PIEDMONT DISTRICT. CHARLES S. PROSSER, CHIEF OF THE APPALACHIAN DISTRICT. GroRGE B. SHATTUCK, CHIEF OF THE COASTAL PLAIN DISTRICT. Harry FIELDING REID, ; : : i 3 2 : CHIEF OF THE HIGHWAY DIVISION. L. A. BavsEr, CHIEF OF THE DIVISION OF TERRESTRIAL MAGNETISM, And with the cooperation of several members of the scientific bureaus of the National Government. > it Ane! ‘ A lagi ‘ i - ¥ of , v4 , i } dd i ay 'd "y © ie » 4 ’ % id ri - 4 7 i 1 ae i . “4 By ; uj ’ i . : LETTER OF TRANSMITTAL To His Excellency Jounn Wavrer Suirn, Governor of Maryland and President of the Geological Survey Com- mission. Sir:—I have the honor to present herewith the first volume of a series of reports dealing with the systematic geology and paleontology of Maryland. A clear comprehension of our geological formations is based on a knowledge not only of the materials out of which the strata are composed, but also of the remains of animal and plant life which are entombed in the rocks themselves. A thorough knowledge of both these factors is essential as a basis for a complete interpretation of the mineral resources of the state, while the educational and _ scientific value of such information cannot be overestimated. It is the purpose of the Survey to publish a number of similar reports which will embrace the entire sequence of Maryland formations. Already much progress has been made in the investigations for the subsequent volumes of the series. Jam, Very respectfully, Wiitiam BuLLock CLARK, State Geologist. JOHNS HOPKINS UNIVERSITY, BALTIMORE, April, 1901. CONTENTS PREFACE ..... THE EOCENE DEPOSITS OF MARYLAND. By WiiuraAm BuULLocK CLARK AND GEORGE CURTIS MARTIN. , INTRODUCTION. . HISTORICAL REVIEW..... BUBB TN OGIVA BE eich. cite w ssberernselens oye GENERAL STRATIGRAPHIC RELATIONS (CHREUECCOHEL GS aida a5 dicSie aed Scr SG ORROR EC REPEL cu et RIE REE ae aCe i ee a Hocene ....... ROS. OO Grind Cp oro O- 5S SM ARE eae ER PAPE RRA ene reir Neocene 5... 5.4. SI ORG RUSE CRSP eds eer eure Pleistocene.... DISTRIBUTION OF STRATA , IDXSNE TENE: 's orci 0 855G-S ear cle A URE OTS IR ROR es PAN Crea eae | ae WIGHVGIEN AGL Cictciniore Grete © eR CCHDCRETONS clo con a Ee Sea enn NGUERT ACY C6 ob oe Coreen GENERAL CHARACTER OF THE DEPOSITS Composiloniee ater eerie. SO OG GOOG SOD CO OOO Cecio oad Ota ROSA oe ror Ce Sink: ACL DI} os casce clotetonereters ar SWe eeu e re Covle cabeey ecenstinusrats Seen errere Sve netic ne eee ene BUI CATES Slategapeace cen iWeuctevslicen otcveNeicia oateshters ctr Goce varan Seal ssid alaitslere ©. aystenarevs.agelelave’s OTC INGE OFM IHU es VACHE UTAUES Gy oyare tact cei e ok inie isi alicrelerehovoscie: ores sen ais eis Onoinvote Green's am dee pacscissscievsisieieve sista TS crouse a cidie sya Wee Sle Meee on eanois wes WM epbhworS CaimemtiabiOimeesiaericce nes erstoero cloronskole Giclee eusnelcl et die oe oma Siete STRATIGRAPHICAL AND PALEONTOLOGICAL CHARACTERISTICS............... Hormations and Haunal Stages ................ Pn eer * orien say Her ne, LS ACTA NOMMAUIOM OF SUE. 66 ooanouoooseodnoabes boadocac Bed ocuboe ANS IEURCRIE ERY NuIGIINaeIy OP SHOES 4 56 6gcb cago sosue oan soon acdooe ANTS IPAS OUAMSE WiGimnl ey Or SW OSE. 5 Gesoobdedaae sa5asdocGsuoasGor INAS Wika GUNOH7 VOMUNENMOM, OP SUG . os soccccc0sons5s0sssancnseouacUsde WAS IPOUETACO NUGIEN NEP. Ole SOMERS — on oocc0soags0sa55 4052020 4cddoue INNS WOCCRUOClE MICU NEP OF WOME ooo! Goosgboneseucuous coo msl Joe ILOCAll MECHIOMNSS 34 oa5p odd oakyoUpesdoude Bp ODEO Gun Secor UO eeaonEE. TUNES IOOWOUNG INVER SECUIOM, o4oescagcacscgocoobeupcodued sucgup ous oOS Quner SSCWOMS oo dé bce oc pee no ben Seo See OO nd dbase conte cou Dor orn GEOLOGICAL AND GEOGRAPHICAL DISTRIBUTION OF SPECIES.......-..--.... Table showing Distribution of Maryland Eocene species.................- CORRIMLATTON OF IDGROGMES, «bos goon eaocddocco cod psu scoScaub CUS abs cunSoEe Correlation of the Deposits within the Middle Atlantic Slope............. Correlation of the Deposits with the Eocene Formations of the Gulf States. PAoOMIOIGSIGal CME) a6 Sogogeoces adcdccodSvoboo scons soe eaUI IO DORe Gi@ollaiicall Cian, o osadedoccpoccde 35 Son vadsen aoa aasdcoss ou Iagos acc IDMAOOEMM IBGE B Song oeeeesess 566d Sos ooops adc bsSSeoussaecos duos 12 CONTENTS SVS LE MATIC PAL WON TOTO GYCuE © CHINE, -ic ee eee re ae Reptilia. -By i. (Cr Case iety yo tces ers neues cisco le a Ot eRe RRC TEN Pisces. I By Charles R., Wastmane cite ascis cc ss vlcrva cise ho cane eee tae emer een ecse ATENTODOAA. © BY) 1.5 OS MUNICH Ses iarc\otan dentine fees ors a Re Te ae Mollusca. . By Wi Bb Clark. andy GAC Martini .2 a 5 ee ae ee ee ee MOlWRsCOtdGG oe 3 sts, « asc fears atone ens Tetei eet a ee tegey e oo: kD OEE EE TEE ee ‘Brachiopoda. By Wi. B) Clark and) GeiCx Martins 2.2 es eee ee ere Bryozods By ir. (Oa WUT Chie ar cm eae rset dete else eit eon coh Date Ba Eee Goclenterata. by iis Wiaydanda Varo hanieererse rerio riers ce ener nae eerie jiingtewecniie Vex WE 1B, Clarks aool G. Cs WEA seeacoogcocccocSeccecunass Protozoa: “BY: Wiz Ms Bag piu Jie toe een ton voters co sone a cnene iat Taio RRR ICR eee Plantae... “By Arthur ROM Nai tec ice coe se he, Sen cae ee ee eae IE SPT AN AUD TON) (ORs PsACLE Sena eieyeieiele ci eae eerie Tap Nahai a> gh ans eae CONOR Ee EERO Cor ogee GENERA, (UNDE oo tg PS Reve ete etree nd ce ae eee We PLATE I. Vis V. Wille Wel. WALLIN JES, ROXIE ROR Ve XVI. EVIE XX: Ke VI NOMS. OMA SIONAIE LVIII. TROSIE NS EOL. TNO CUTE: LXIV. ILLUSTRATIONS FACING PAGE Map showing Distribution of Eocene Deposits in Maryland...., 21 Views of Surface of Hocene Country................. A OPA ri a Be 44 Fig. 1.—Farm- and wood-lands along South River ........... 44 «¢ 2.—Farm-lands near Annapolis Waterworks........ rin he 4 VACRENG EM OGONONSECHIOMG tee dis isiwieieialnielfieavevu nie svouctelemartatee mie 458 Fig. 1.—Zones 2 to 6 at mouth of Aquia Creek .............. 48 « 2.—Blocks of Zone 9, largely composed of Twrritélla PORNO. & coe BGO CC, COPNCET COICO IOIZ EL ae eon OU DORA Acie Acie 48 Wie SrOlME OCONGRSECULO DU Sparerataiccs clcsistercisicte atcfebatel stajenersioieerees eens 56 Fig. 1.—Fort Washington bluff, basal Eocene overlying GOnetaceoulsataacvrasrsrieap vrais ayetelay eww vis, 2 rel higreReiaredalane tee ate tote 56 Fig. 2.—Zones 2 tu 4 at base of Aquia Creek bluff........... 56 yeneral Columnar Section of Eocene Deposits in Maryland..... 64 Local Columnar Sections of Eocene Deposits in the Potomac WETS S33 os Ae TBI OS Cees ect let tater aT a meee Ea Be ate ae 68 VEIONAS One INCNE STOO NG 5 AS Goo co pd ede Coed Ho One Ic GOS 72 Fig. 1.—Lower Eocene Deposits on Severn River............ 72 « 2.—Indurated layer of Upper Marlboro, overlying Bryo- OEM SOINGS 55.6% bn God bP AsO po SAS OO Mode On Beet So8o0 72 Wiis OF WES NS SCHON ose dagnoateomenoeadH OO acs ob oon oe 84 Fig. 1.—Contact of Nanjemoy and Aquia Formations in Valley ombeardaGneekorAmnesArumnd el County seein = enero = 84 Fig. 2.—Contact of Nanjemoy and Aquia Formations at Upper Mars OM: One esos covets icnciorere one: wists 5. eve fever snapavere\aue yews Soa, cueleele es 84 NAIGWASS OIE IBOYESINE SICCHHOMS 2.5 cu0H doce seangsepevhouygn conde eee 88 Fig. 1.—Railroad Cut near Upper Marlboro showing Nanjemoy OMMNRHHNKOI Oyerolenun lon hie Cleo SS oe 55Ga5gocn asaocoo- 88 Fig. 2.—Popes Creek bluff showing Zone 17 overlain by NIM@OSINS IDE TOMARCAOUIS CARIN, 55 440s nscoooccsgoneaccecde 88 IME OLUUNTE 5 6 W'Wole Met obo to ous cose Mey ews icone aves, Seine s BO eOO IEMROCS ia pac cob Ua dbe Bad Oped dn EE Deo OE OO eo ese namie Geis od 264-267 AADC HOCH —CihiGKACGE, Gocogssusoegadqe soos bs acu son ono doo see 268 Molinisca==Cephalopodaenarscccciusa-en eeee tae cOO—o nL Miolitsca——GastroOpOd aires stance erm cle) elcrer=isjenaccis en oleke ue a, clare o's 272-280 Mollusca—Gastropoda and Scaphapoda....................... 281 MIGUNTSOR—1PSUBOVIDOUEY so ce caanocc nc ods odes eu edu ouD GOSS oS- 282-309 Nolitiscoidea=— brachiopod demerits retell s-a- 310 NKOUNTISCONCIEA—— IFOAM. oo ca once ne aoodu con bo Sees sen UGdUde 311-312 Hehinoderntataands Coelenterata -ewetrere tie < etree cris) ciation = 315 IPPOUCAON— IN CRATMMUEN, Sooo ec aneoecatadenceocucs duecdoe 314-515 Protozo1—horanmimitersd ean Gblamtade err se ele see reierele se ela 316 PREPACE The present volume is the first of a series of reports dealing with the systematic geology of Maryland. ‘These reports will appear from time to time as the several investigations are completed, but not neces- sarily in geological sequence. By reference to Volume | of the Survey it will be seen that the geological sequence of Maryland rocks is as follows: Pleistocene ; Cenozoic ~ Neocene Kocene Mesozoic fpenernerOUsy ; ({ Jurassic-Triassic { Permian-Carboniferous . | Devonian oe ae in oc [ Cambrian Archean Algonkian-Archean Some of these divisions are more extensively developed in Maryland than others so that the contemplated reports will differ greatly in size. The oldest division, comprising the Algonkian-Archean, is entirely des- titute of organic remains in Maryland, while the Jurassic-Triassic is -nearly so. The other seven divisions, however, contain either rich faunas or floras; three of them, the Permian-Carboniferous, the Cre- taceous and the Pleistocene containing both animal and plant fossils. These reports when completed will give both to the geologist and to the general reader a comprehensive view of the past history of Maryland territory from the earliest geological period to the present day. For educational purposes the volumes cannot fail to have much value, and will find frequent use in the hands of those who are seeking to acquire a knowledge of the physical and faunal history of the State of Maryland. The present volume on the Eocene deals with the earliest period of = | the Cenozoic and, with the Neocene, embraces what is frequently de- 16 PREFACE nominated by geologists as the Tertiary. As will be shown in later pages the Tertiary rocks of Maryland are of wide extent and contain much of interest from both a scientific and practical standpoint. The Eocene deposits of Maryland have received for many years the close attention of the senior author of this paper, and his observations have been supplemented recently by the work of the junior author. A report made by the senior author to the Director of the U. 8. Geo- logical Survey in 1896 is extensively drawn upon for the present vol- ume, many of the general descriptions being taken directly therefrom, with such changes and additions as the present enlarged knowledge of the subject may require. Dr. R. M. Bagg, Jr., also spent portions of two field seasons in a study of the local stratigraphy under the personal direction of the State Geologist and prepared a series of preliminary maps covering a large part of the area. The paleontological investigations have been jointly conducted by several experts. In addition to the sections for which the authors of the report are personally responsible, aid has been rendered in others by several well-known students. The Reptilia have been studied by Dr. E. C. Case of Milwaukee, Wis- consin; the Fishes by Dr. Charles R. Eastman of Harvard University, Cambridge, Massachusetts; the Crustacea and Bryozoa by Mr. E. O. Ulrich of Newport, Kentucky; the Corals by Mr. T. Wayland Vaughan of the U. 8. Geological Survey; the Protozoa by Dr. R. M. Bagg, Jr., of Colorado Springs, Colorado; and the Plants by Dr. Arthur Hollick of Columbia University, New York. Mr. Charles Schuchert of the U. 8. National Museum has revised the descriptions of the Brachiopoda. Extensive collections of material were made preparatory to this work, and all the leading fossiliferous localities of the state were visited. The greatest amount of material was obtained, however, from the bluffs along the banks of the Potomac river, which afford the most complete section of the Kocene in the Middle Atlantic Slope. In general, the fossils of this region are difficult of removal, as they readily crumble at the touch, so that some process of hardening had to be employed to preserve them permanently. ‘To this fact more than to any other cause, has been due MARYLAND GEOLOGICAL SURVEY 17 the small size of the collections of Eocene specimens found in the various museums of the country, as compared with the collections of Neocene forms from the same area. ‘lhe forms figured and described in this report have come, with scarcely an exception, from the collections of the United States National Museum, the Academy of Natural’ Sciences of Philadelphia, the Johns Hopkins University, and the Maryland Geo- logical Survey. The Museum of the Academy of Natural Sciences of Philadelphia contains Dr. Conrad’s types, which have been most im- portant in definitely determining the species hitherto described. The State Geological Survey desires to express its thanks for the aid which has been rendered by the several experts who have contributed to this volume; also to the U. 8. Geological Survey which has generously allowed the use of many of its plates and drawings, which have materially reduced the expenses of publication; and to Professor G. D. Harris for the loan of several drawings. Many important suggestions have also been received from Dr. W. H. Dall of the U. 8. Geological Survey, Professor H. A. Pilsbry of the Philadelphia Academy of Natural Sciences and Mr. C. W. Johnson of the Wagner Free Institute of Science. They have examined many of the determinations of fossils, and have thus materially contributed to the accuracy of the report. Thanks are also due to the artists Mr. J. C. McConnell of the U. 8. Army-Medical Museum, Mr. H. C. Hunter of the U. 8. Geological Sur- vey and Mr. F. von Iterson for the beautiful drawings with which the report is illustrated. Jats OG BIE BIG EOS ITES OF MARYLAND BY WILLIAM BULLOCK CLARK AND GEORGE CURTIS MARTIN ‘ \ ware Dg - \ i > ‘ \ ‘Ga co = ei i x ‘ eS i é - ; : a y . . ‘ } , i ah AN MT : - bar) eee j ) it ae ‘7 ve _ Yo @ te av. We ts a. Ba ya ater MARYLAND GEOLOGICAL SURVEY EOCENE, PLATE | SHOWING THE DISTRIBUTION OF THE EOCENE FORMATIONS OF coTT MARYLAND BY WM. B. CLARK AND GEO. C. MARTIN Seale 1:500,000. 8 miles = 1 inch MARYLAND GEOLOGICAL SURVEY WM. BULLOCK CLARK, STATE GEOLOGIST 1901 Sr) CHESAPEAKE BEAC x A “y 0. Ou sénstown : oi \ a oe pe OM EGT <3) / TS Ay a, LEGEND: ral Nanjemoy Formation Aquia Formation * Fossil Localities NOTE. The Nanjemoy formation is divided into the Wooa- stock member which consists of argillaceous greensands, and into _| the Potapaco member which is composed of argillaceous sands above and clays below. The Aquia formation is divided into the Paspo- tansa member which consists of ledges of greensand marls under- lain by gveensands, and the Piscataway member which is composed of interstratified layers of indurated greensand marls and incoherent greensands. tits BOCENE DEPOSITS OF MARYLAND BY WILLIAM BULLOCK CLaRK and GEORGE CurRTIS MARTIN INTRODUCTION. Maryland, as an important division of the Atlantic border region, comprises in its geology and mineral resources much that is typical of the entire province. No discussion of Maryland geology, therefore, can be regarded as complete that does not at the same time take into con- sideration the formations of immediately adjacent states. Much may be learned in this way that will be of advantage in interpreting our own geology, since geological deposits are not limited by political boundaries. Maryland, together with Delaware and Virginia, forms what has with propriety been termed the Middle Atlantic Slope, and, as described in the earlier volumes of the Survey, has been divided into the Coastal Plain, the Piedmont Plateau, and the Appalachian Region. The pres- ent report is confined to a consideration of only a part of the first of these divisions. Much interest has been manifested in the Coastal Plain geology and paleontology of the Middle Atlantic Slope since the early days of geo- logical investigation in this country. Many of the most potent illus- trations of the geologists of the early part of the century were drawn from this region, and although the relations of the deposits were not altogether comprehended, yet the recorded observations show an appre- ciation of many of the more difficult problems involved. Later, as the complicated geological history of the Coastal Plain became better known, it was recognized that, if a full understanding of any single formation was to be gained, it was necessary to study carefully not only its litho- logical and paleontological characteristics but also its relationship to 22 THE EOCENE DEPOSITS OF MARYLAND the other members of the series. It was seen that only by an under- standing of the broad conditions affecting the whole district could the strata of any one formation be properly interpreted. Recognizing this fact, the writers present in later pages a brief discussion of the general. relations of the strata composing the Coastal Plain in the Middle At- lantic Slope. The fuller discussions will be found in the-later volumes dealing with these formations. When we come to consider that assemblage of deposits (Eocene and Neocene) early separated as the Tertiary, we find that it is divisible into several distinct formations. Even at a relatively early date an older and a younger Tertiary were already established, the former being corre- lated with the Eocene of England and the European continent. At- tempts were made then and later to find its exact equivalent in one or another of the already established local formations of the English or continental series, but with very unsatisfactory results. . After the American Eocene strata had received somewhat detailed examination in the various sections of the country and local divisions had been established, attempts were made from time to time to deter- mine their equivalency. By common consent the diversified and exten- sive deposits of the Gulf area came to be regarded as the type for the eastern border region, and the various Eocene deposits of the Atlantic Coast States were assigned to positions in this series. Some authors, recognizing the presence of a few identical species, have referred the strata now under consideration to a single minor division in the scale, while others have regarded the Maryland-Virginia deposits as repre- senting a larger portion of the Gulf series. After a careful consideration of both the paleontological and the geological data, the writers deem the latter conclusion the only tenable one. Attention has been devoted in the past too exclusively to supposed faunal similarities, upon the most insufficient knowledge of the forms, and too little to the character of the sedimentation. Important as the former are when the fauna has been fully investigated, and the writers would be far from disparaging that importance, yet the widely different physical conditions surrounding the accumulation of the deposits in the two areas must at the same time be regarded. Change in a fauna is MARYLAND GEOLOGICAL SURVEY we not to be measured by the time standard alone, but also by the condi- tions of life, whether constant or variable, to which the forms may be subjected. Persistent conditions must of necessity have less effect than those which are changing. A satisfactory correlation of the strata in districts so widely separated as the Middle Atlantic Coastal Plain and the Gulf Region can be attained only by a proper appreciation of the bearing of these factors on faunal development. In the Middle Atlantic Slope the relatively homogeneous nature of the Eocene deposits is a characteristic feature, indicating that through- out the period of deposition the conditions were undisturbed by import- ant physical changes. The fact that the deposits are made up largely of secondary materials shows in a general way that their accumulation took place near a coast reached by few large sediment-bearing rivers, and that at the same time the place of deposition was sufficiently removed from the coast line to be unaffected by shore conditions. In the Gulf Region, on the other hand, deposition was more rapid, since a great quantity of detrital material was brought to the sea by the large streams draining the interior of the continent. The bearing of these different physical conditions upon the interpretation of the two areas and the correlation of their deposits will be fully considered in the body of the report. The materials of the Eocene of the Middle Atlantic Slope, which are so largely glauconitic, are of no little interest in themselves outside of their bearing upon the questions of correlation, since few areas afford ‘such extensive deposits of greensand. On that account alone they de- serve special consideration, and a chapter will be devoted to this phase of the subject. The description of new species of fossils is of little scientific impor- tance to the geologist unless the object is something other than the mere multiplication of new forms, which has too often been the case in such investigations. When, however, the work has in view the fullest possible representation of a fauna or the clearing up of doubtful points in the synonymy of already described species, as well as a more complete knowledge of their geological and geographical ranges, it becomes of the very greatest value, since one whole class of important criteria for 24 THE EOCENE DEPOSITS OF MARYLAND the interpretation of the strata is thus made accessible. The present report includes the results of such an exhaustive study of the fauna of the Eocene of Maryland, together with a critical review of the species described by previous authors, as well as the description of a large num- ber of new forms. It is believed that a much more accurate idea of the faunal characteristics, as well as of the physical conditions prevailing during the Eocene period on the Middle Atlantic Coast, will result from the methods pursued in this investigation. Certainly the data for the comparison of the fauna with those of other areas will be greatly aug- mented. Historicat REVIEW.’ On account of its extensive waterways and the ready access thereby gained, the Atlantic Coastal Plain was early visited for purposes of geo- logical investigation. At first the observations were of the most general character, no attempt being made to differentiate the deposits or even to correlate the strata as a whole with those of other districts. Among the earliest investigators of the region was Professor Peter Kalm, who was sent out in 1749 under the auspices of the Swedish Royal Academy of Sciences to make a study of the various branches of natural history in America, and who spent considerable time in a study of the northern Coastal Plain. He was followed in 1777 by Dr. Johann David Schopf, of Germany, who visited America in order to study the geological features of the eastern portion of the continent. The importance of his observations, which mark considerable advance over those of Kalm, has not been very generally recognized by later writers, but he showed a remarkably keen insight into the geology of eastern North America, which was lacking on the part of some of his successors. The first attempt to correlate the deposits of the eastern United States with the geological column then established in Europe was made by William Maclure, in 1809, in his Observations upon the Geology of the 1 Both in this and in the subsequent chapter, comprising the Bibliography, refer- ences are made to articles and books dealing also with the Eocene of Delaware and Virginia since the deposits are embraced in the same geologic province with those of Maryland, MARYLAND GEOLOGICAL SURVEY 5) United States. In this publication the coastal deposits of the Middle Atlantic Slope are collectively referred to the “ Alluvial formation,” the fourth of the main divisions of geological strata originally proposed by Werner. The work was subsequently revised and enlarged, appearing in book form in 1817. In 1820 H. H. Hayden, of Baltimore, published a volume of Geological Essays, in which he attempted to explain the great accumulation of “alluvial deposits” in the Atlantic Coastal Plain. In this volume the stratigraphy of the region is described in much greater detail than by his predecessors, and reference is made to the wide distribution of fossil shells and vertebrate remains, many localities being cited. A volume of the same character, so far as it relates to the geology, was published in 1822 by Parker Cleaveland, entitled an Elementary Trea- tise on Mineralogy and Geology, in which, on page 785, under remarks on the “Geology of the United States explanatory of the subjoined ce geological map,” the limits and the lithological character of the “ allu- vial deposits ” are described in general terms. By far the most important contribution to the stratigraphy of the Atlantic Coastal Plain that had up to that time appeared was made by Professor John Finch, in a “ Geological essay on the Tertiary formations in America,” in the American Journal of Science and Arts for 1824. This was the first attempt at a division of the deposits of the Coastal Plain and their correlation upon scientific grounds; and although thus early in the history of the subject detailed comparisons (which are always unsatisfactory) were made, yet the knowledge of the formations was materially advanced. ‘The author says: In America an immense tract of country, extending from Long Island to the Sea of Mexico, and from 30 to 200 miles in widtb, is called an alluvial formation. From an examination of fossils brought from that quarter of the United States, from a personal inspection of some of its strata, and the perusal of most of the publications which bear a reference to it, [ wish to suggest that what is termed the alluvial for- mation in the geological maps of Messrs. Maclure and Cleaveland is identical and con- temporaneous with the newer Secondary and Tertiary formations of France, England, Spain, Germany, Italy, Hungary, Poland, Iceland, Egypt and Hindostan. The deposits of various portions of the Middle Atlantic Slope are considered in greater or less detail, and correlations with the strata of 26 THE EOCENE DEPOSITS OF MARYLAND other portions of the Coastal Plain and with Europe are attempted. The author states in short that— Many more instances might be advanced to establish the identity of what has been called the alluvial district in America with the Tertiary formation of England and the continent of Europe. The fossil shells from the various beds would not, perhaps, be exactly like those of Europe, but a sufficient number would be found so to establish ‘their relation and order of succession. € During the year 1825 Jer. Van Rensselaer delivered in the New York Athenaeum a course of geological lectures that were subsequently pub- lished in book form. The author adopted the classification proposed by Finch, confining his descriptions, however, more particularly to the formations of the northern Coastal Plain. The American Journal of Science for 1826 contains a communication by James Pierce “ On the shell-marl region of the eastern parts of Vir- ” in which reference is made to the sections on the ginia and Maryland, James and Potomac rivers and to the “shell rock” at Upper Marlboro. A few years later (1828) Professor Lardner Vanuxem, through his friend, Dr. S. G. Morton, presented the criteria for a more complete and definite recognition of the several members of the coastal series, and described both the Cretaceous and Tertiary formations. In this article an attempt is made to define more accurately the limits of the Tertiary. The author states that much that had been designated by that name properly belongs to other formations. Up to the year 1830 all investigations of the stratigraphy of the Ter- tiary had been carried on in the main independently of a study of the fossils. Generic identity had been cited as ground for correlation, and although this aided largely in determining the limits of the Tertiary itself, further subdivisions were impracticable. The publication of Conrad’s article “On the geology and organic re- mains of a part of the peninsula of Maryland,” with an appendix con- taining descriptions of new species of fossil shells, inaugurated a new era in the investigation of the Coastal Plain strata. It is true that Say had already described several Tertiary species, including the common ~Ostrea compressirostra of the Eocene of the Middle Atlantic Slope, but, as stated in Conrad’s paper, he did not “draw any geological inferences MARYLAND GEOLOGICAL SURVEY co ~ from the organic remains examined.” Conrad from the first applied the paleontological evidence he had acquired to an interpretation of the stratigraphy; and, although many of his conclusions were erroneous, the knowledge of the geology of the Coastal Plain was very materially ad- vanced by his work. In this first paper such well-known early Ter- tiary forms as T'wrritella mortoni, Cucullaea gigantea, and Crassatella alaeformis are figured and described, while the presence of Venericardia planicosta Lamarck is also noted. By the use of the data afforded by these investigations the strata at Fort Washington, were correlated with the London Clay of England. In 1832 Conrad began the publication (in parts) of an important work entitled “Fossil shells of the Tertiary formations of North America.” This and its companion volume upon the “ Middle Ter- tiary,” commenced some years later, must be regarded as thé basis of all later work upon American Tertiary paleontology. In the earlier publi- cation Conrad regarded the deposits in the vicinity of Fort Washington, as “ Middle Tertiary,’ and correlated them with the London Clay and Calcaire grossier of Europe, and the Claiborne beds of Alabama. Before the completion of Conrad’s first work above mentioned Lea published his “ Contributions to geology,” in which a large number of Eocene fossils are described and the stratigraphy of the Tertiary of the Atlantic Coastal Plain is discussed. Im this work the term Eocene is first applied to the American Lower Tertiary deposits, although the general position of the deposits had already been recognized by Conrad. The latter, however, in 1834, in his “ Observations on the Tertiary and more recent formations of a portion of the Southern States,” employs the term Eocene for the Fort Washington deposits, although he there their Miocene age. . During the same year Professor William B. Rogers made his first con- tribution to the Eocene geology of Virginia, and although this article contained little of real importance, it is of interest as being the first of a series of important publications upon the geology of Virginia. Dr. S. G. Morton, whose investigations were chiefly confined to the Cretaceous, gives in his “Synopsis, etc.,” published at this time, a 28 THE EOCENE DEPOSITS OF MARYLAND “ Catalogue of the fossil shells of the Tertiary formations of the United States,” in which many of the Middle Atlantic Slope forms are included. During the year 1835 several important contributions were made to the geology of the Atlantic Tertiary region. Conrad published his in- vestigations upon the Maryland-Virginia Tertiary area, including the description of two new species of Eocene fossils. Rogers presented “Further observations on the greensand and calcareous marl of Vir- ginia,” in which the lithological similarity of the beds to the greensand deposits of New Jersey is dwelt upon, although he believes that the character of the organic remains shows the strata to be Kocene. Jointly with his brother, H. D. Rogers, he presented to the Philadelphia Acad- emy of Natural Sciences the first portion of “‘ Contributions to the geol- ogy of the Tertiary formations of Virginia,’ in which several new species of Eocene fossils are described. While the investigations hitherto mentioned were being carried on privately, the three states constituting that portion of the Middle At- lantic Slope now under consideration, viz., Delaware, Maryland, and Virginia, became aroused to the importance of official geological surveys of their areas. The first to organize such a survey was Maryland, in 1833, J. T. Ducatel being appointed State Geologist. Reports were published until 1841, but the information they contain is economic rather than strati- graphic. The Geological Survey of Virginia began operations in 1835, under William B. Rogers as State Geologist, who was thus able to continue much more systematically than hitherto his observations upon the Ter- tiary belt. The first report, for 1835, which contains a general state- ment regarding the “ Eocene mar! district,’ and most of the subsequent annual reports, which were continued until 1841, include more or less detailed descriptions of the Eocene deposits. Collectively they form the chief source of information regarding the Eocene stratigraphy of Virginia. The Geological Survey of Delaware was short lived. Its investiga- tions, under the direction of I. C. Booth, State Geologist, extended only on over the seasons 1837 and 1838, for which years annual reports were MARYLAND GEOLOGICAL SURVEY no published, and, in addition, a more exhaustive “ Memoir” in 1841; but in none of these publications was the Eocene recognized as such. Conrad, who actively continued his investigations, made an import- ant contribution to the Eocene of the Middle Atlantic Slope in 1842 in his “ Observations on a portion of the Atlantic Tertiary region, with a description of new species of organic remains.” During this year the first of Lyell’s publications upon the eastern Tertiary belt appeared in the Proceedings, of the Geological Society of London. His conclusions were derived from personal observations, and were of special value from his wide knowledge of the Tertiary of Europe. He succeeded in explaining many points in American Tertiary stratigraphy hitherto imperfectly understood. The narrative of his first report contains the following statement: Having examined the most important Cretaceous deposits in New Jersey, Mr. Lyell proceeded in the autumn of 1841 to investigate the Tertiary strata of Virginia, the Carolinas, and Georgia, with a view to satisfy himself, first, how far the leading divisions of Tertiary strata along the Atlantic border of the United States agree in aspect and organic contents with those of Europe; and, secondly, to ascertain whether any rocks containing fossils of a character intermediate between those of the Cretaceous and the Eocene beds really exist. The conclusions at which he arrived from his extensive survey are given briefly as follows: (1) The only Tertiary formations which the author saw agree well in their geological types with the Eocene and Miocene beds of England and France; (2) he found no secondary fossils in those rocks which have been called Upper Secondary and supposed to constitute a link between the Cretaceous and Tertiary formations. The Eocene deposits upon the James River, Virginia, are described in this paper. In his subsequent papers bearing upon the Eocene of the Middle Atlantic Slope the stratigraphy of the Eocene is further considered and references are made to other localities which he visited. Murchison, in his presidential address before the Geological Society of London in 1843, reviewed the results of Lyell’s investigations in — America and added his own interpretation of a few points. During the years immediately subsequent to Lyell’s visit many im- portant articles upon the Tertiary appeared from the pens of American geologists, although the publications dealt more largely with the south- ern than the northern deposits. Conrad, however, made additional observations upon the Eocene strata of the Middle Atlantic Slope and 30 THE EOCENE DEPOSITS OF MARYLAND described a number of new species. About this time Henry C. Lea pub- lished a ‘“‘ Catalogue of the Tertiary Testacea of the United States,” in which the Middle Atlantic Slope forms are included. Subsequent to 1850 interest in the Tertiary geology of the Middle Atlantic Slope seems for a time to have waned, and during the next twenty-five years very few investigations were carried on within the dis- trict. In Maryland two surveys, partly of a geological but more largely of an agricultural nature, were inaugurated, the first, under James Hig- gins, producing six reports between 1850 and 1858, and the second under Philip T. Tyson, who presented two reports in 1860 and 1862. In the report for 1860 the Tertiary is described in some detail, although no attempt is made to establish the limits of its several divisions. Conrad continued, however, to carry on his investigations upon the Atlantic Tertiary belt, adding to the number of new fossil forms and publishing two catalogues of species. During the last twenty-five years, and particularly in the latter part of this period, many more contributions have been made to the geology of the Middle Atlantic Slope. Among those who have given the subject attention may be mentioned McGee, Heilprin, Darton, Uhler, Shattuck, Bibbins, Harris and the authors of this report. To the publications of McGee we are indebted more than to any other for a general statement of Coastal Plain conditions. Although some modifications have been deemed necessary after a detailed study of the formations, the writers are impressed, from a careful examination of large portions of the area, with the general correctness of the broad principles enunciated by him. Heilprin has devoted considerable attention to Atlantic Coast paleon- tology, comparing several of the Eocene species of Maryland and Vir- ginia with European forms, and correlating the strata, as a result of these investigations, with the lower members of the English and French series. Both Darton and Uhler have studied the local relations of the Eocene deposits, the former having prepared several United States Geo-— logical Survey atlas sheets of the central and southern portions of the district. Others have turned their attention from time to time to the area, and from their knowledge of other districts have aided to a greater or less MARYLAND GEOLOGICAL SURVEY 31 degree in interpreting the geology of the Eocene of Maryland. ‘The articles contributed by all the various workers in this field are given in the bibliography. 3IBLIOGRAPHY. AupricH, TI. H. Notes on Eocene Mollusea. Bull. Amer. Pal., vol. ii, No. 8. Crassetalla declivis Heilprin and Ringicula dalli Clark are figured Baae, R. M. Jr. Contributions to the Eocene fauna of the Middle Atlantic Slope. Protozoa. Johns Hopkins Univ. Cire., vol. xv, 1895, p. 6. Spiroplecta clarki is described from Woodstock, Virginia. ——— The Eocene Deposits of the Middle Atlantic oheale in Dela- ware, Maryland and Virginia. Protozoa. Bull. 141, U. S. Geol. Survey, 1896, pp. 91, 92 A list of Hocene Foraminifera is given. The Tertiary and Pleistocene Foraminifera of the Middle At- lantic Slope. Bull. Amer. Pal., vol. ii, No. 10, 1898, pp. 295-3 Several Eocene species are figured and described. 8 (1-34), pls. Xxi-xxiii (i-iii). The occurrence of Cretaceous fossils in the Eocene of Mary- land. Amer. Geol., vol. xxii, 1898, pp. 370-375. The author mentions the occurrence of Terebralula harlani and Gryphaea vesicularis in the Maryland Hocene. Battery, J. W. Notice of some New Localities of Infusoria, Fossil and Recent. Amer. Jour. Sci., vol. xlvili, 1845, pp. 321-343, pl. iv. Mentions occurrence of casts ‘‘ in some of the Eocene marls from Fort Washington ——— On the Origin of Greensand, and its formation in the oceans of the present epoch. Amer. Jour. Sci., 2nd ser., vol. xxii, 1856, pp. 280-284. Proc. Bost. Soe. Nat. Hist., vol. v, pp. 364-368. Author again refers to “ casts ’’ found in Fort Washington Eocene. BasstEeR, Ray S. and Nicxies, Joun M. A Synopsis of American Fossil Bryozoa. 79 Bull. 173, U. S. Geol. Survey, 1900, p. 72. Upper Marlboro is included in the list of Eocene localities 32 THE EOCENE DEPOSITS OF MARYLAND Bootu, J. C. Memoir of the Geological Survey of the State of Dela- ware, including the application of the geological observations to agri- culture. Dover, 1841, 8vo, xi and 188 pp. The author gives a description of the Upper Secondary and Tertiary formations, but does not distinguish the Hocene. CuarK, Wittiam Buiiock. On three geological excursions made during the months of October and November, 1887, into the southern counties of Maryland. Johns Hopkins Univ. Cire., vol. vii, 1888, pp. 65-67. Reference is made in this article to the Hocene of Upper Marlboro and Port Tobacco, Third annual geological expedition into southern Maryland and Virginia. Ibid., vol. ix, 1890, pp. 69-71. The author describes the Hocene section of the Potomac river valley in Maryland and Virginia. Report of the scientific expedition into southern Maryland. Ibid., vol. x, 1891, pp. 105-109. Much of the same areas are described in this report as in the preceding paper. Correlation Papers—Eocene. Bull. 83, U. 8. Geol. Survey, 1891, pp. 43-48, 80, 81, 85-87. The author gives a digest of the literature of the Eocene of the Middle Atlantic Slope, as well as a description of the deposits. Correlation is made with the lower and middle divisions of the Gulf series. —— Outline of the geology and physical features of Maryland. The Eocene. In Maryland, its Resources, Industries and Institutions, Baltimore, 1893, pp. 53-56. In this report the author gives a brief description of the Eocene deposits of Maryland. ——— The climatology and physical features of Maryland. First Biennial Report Md. State Weather Service, 1894, pp. 38-39. Description of the same area as in the preceding report. ——-— Contributions to the Eocene fauna of the Middle Atlantic Slope. Johns Hopkins Univ. Cire., vol. xv, 1895, pp. 3-6. This article contains a list and discussion of the Hocene species of Delaware, Mary- fand and Virginia, with the description of 32 new forms. The part upon Corals is pre- pared by Vaughan, that upon Foraminifera by Bagg. ——— The Potomac River Section of the Middle Atlantic Coast Hocene. Am. Jour. Sci., 4th ser., vol. i, 1896, pp. 365-374. A detailed section of the Potomac river section is given. MARYLAND GEOLOGICAL SURVEY 33 The Kocene Deposits of the Middle Atlantic Slope in Dela- ware, Maryland and Virginia. Bull. 141, U. S. Geol. Survey, 1896, 167 pp. 40 plates. A general discussion of the geological features, distribution, character and correlation of the deposits, with a description of the contained fossils. A number of new species are added. Outline of present knowledge of the Physical Features of Maryland, embracing an account of the Physiography, Geology, and Mineral Resources. Md. Geol. Survey, vol. 1, 1897, pp. 195, 196, 217. The Hocene deposits of the state are described. — Collection of Eocene Fossils. Johns Hopkins Univ. Cire., vol. xviii, 1898, No. 137, p. 18. The author substitutes the name Pecten dalli for Pecten rogers: which was already pre-empted. CLEAVELAND, PARKER.—An elementary treatise on mineralogy and geology. Remarks on the geology of the United States explanatory of the subjoined geological map, Boston, 1822, 785 pp. The author defines the limits of the ‘‘ alluvial deposits’’ and in general terms describes their lithological character. Conrad, T. A. On the geology and organic remains of a part of the peninsula of Maryland. Jour. Acad. Nat. Sci., Phila., vol. vi, 1830, pp. 205-217. Reference is made to the deposits of Fort Washington and Piscataway, and correla- tion proposed with London Clay of England. The paper also contains original descrip- tions of Monodonta glandula, Turritella mortoni, Cucullaea gigantea, and Craxsatella alaeformis from this region. Fossil shells of the Tertiary formations of North America, 1832-1835, 56 pp. (including republication No. 3), 20 pls. The author regards the deposits in the vicinity of Fort Washington as ‘* Middle Tertiary,’’ and correlates them with the London Clay, Calcaire grossier and Claiborne beds. He also describes Cardita planicosta and Turritella mortoni from Piscataway. ——— Observations on the Tertiary and more recent formations of a portion of the Southern States. Jour. Acad. Nat. Sci., Phila., vol. vii, 1834, pp. 116-129. Mention is made of the deposits of Fort Washington, which are considered younger than the strata at Claiborne, Ala., perhaps Miocene in age. —-—-— Observations on the Tertiary Strata of the Atlantic Coast. Amer. Jour. Sci., vol. xxviii, 1835, pp. 104-111. Author states that there are no Eocene species common to the Pliocene. Observations on a portion of the Atlantic Tertiary region. Trans. Pennsylvania Geol. Soc., vol. i, 1835, pp. 335-341, pl. xiii. The deposits at Upper Marlboro and Piscataway, and City Point, Va., are considered, and Panopaea elongata and Turritella humerosa from Piscataway described. 3 Ba THE EOCENE DEPOSITS OF MARYLAND Notes on American Geology. Observations on characteristic Fossils, and upon a fall of Temperature in different geological epochs. Amer. Jour. Sci., vol. xxxv, 1839, pp. 237-251. Refers to the Eocene deposits of Upper Marlboro and Piscataway as illustrations of deposition by gentle currents. ——— On the Silurian system, with a table of the strata and char- acteristic fossils. Observations on the Plastic Clay. Amer. Jour. Sci., vol. xxxviii, 1840, pp. 91-92. The authors discusses the relations of the Plastic Clay to the fossiliferous deposits at Piscataway, which it is regarded in some instances to overlie. Observations on a portion of the Atlantic Tertiary region, with a description of new species of organic remains. Proce. Nat. Inst. Prom. Sci., 2nd bull., 1842, pp. 171-194. The deposits of Upper Marlboro, Piscataway and Fort Washington are referred to the Eocene or Lower Tertiary, and at the same time correlated with the London Clay, Calcaire grossier, Claiborne beds, etc. The author also describes Ostrea sellaeformis from City Point, Va., and Pholadomya marylandica and Pholas petrosa from Piscataway. ——_ — Observations on the Eocene formations of the United States, with descriptions of species of shells, ete., occurring in it. Amer. Jour. Sci., 2nd series, vol. i, 1846, pp. 209-220, 395-405, pls. i-iv. The article contains descriptions of Pholas petrosa, Pholadomya marylandica, Pan- opaea elongata, and Crassatella alaeformis from Piscataway, and Crassatella palmula from Upper Marlboro. ——w— Observations on the Eocene formation and descriptions of one hundred and five new fossils of that period from the vicinity of Vicksburg, Mississippi. With appendix. Proce. Acad. Nat. Sci. Phila., vol. iii, 1847, pp. 280-299. The author regards the Fort Washington, Piscataway and Upper Marlboro deposits as lower Hocene. : Observations on the Eocene formation and descriptions of 105 new fossils of that period from the vicinity of Vicksburg, Miss. Appen- dix: Descriptions of new Eocene fossils in the cabinet of Lardner Vanuxem. Jour. Acad. Nat. Sci., Phila., 2nd series, vol. i, 1848, pp. 128-134, pl. xiv. The author considers the Maryland and Virginia deposits as ‘‘ Lower or older Eocene ”’ and correlates them with the ‘ fossiliferous sand of Claiborne and St. Steph- ens, Ala.,’ etec., chiefly from the presence of O. sellaeformis. He also describes Cytherea subimpressa, C. lenis, C. liciata. C. eversa, and Nucula improcera from Hanover County, Va.; Cytherea pyya from Stafford County, Va., and Nucula parilis from Upper Marlboro. —_-. Notes on’ Shells. Proce. Acad. Nat. Sei. Phila., vol. vi, 1853, p. 320. Cytherea lenticularis Rogers is referred to the genus Artemis of Poli. MARYLAND GEOLOGICAL SURVEY 35 — Rectification of the generic names of Tertiary Fossil Shells. Proc. Acad. Nat. Sci, Phila., vol. vii, 1854, pp. 29-31, The generic names of several Bocene fossils from Maryland and Virginia are changed. Notes on shells, with descriptions of new fossil genera and species. ; Proc. Acad, Nat. Sei. Phila., vol. xvi, 1864, pp. 211-214, with figures. Descriptions are given in this article of Protocardia virginiana from Pamunkey River, Va., and Dosiniopsis meekii from ‘6 miles east of Washington, D. C."’ ——— Catalogue of the Eocene and Oligocene Testacea of the United States. Amer. Jour. Conch., vol. i, 1865, pp. 1-35. Among other forms the catalogue contains a list of the Eocene species of the Middle Atlantie Slope. —-—— Descriptions of new Eocene shells and references, with fig- ures, to published species. Ibid., pp. 210-212, pls. xx, xxi. The author describes Lunatia marylandica, but gives no locality. — Check list of the invertebrate fossils of North America (Eocene and Oligocene). Smithsonian Mise. Coll., vol. vii, 1866, art. 6, pp. 1-41. The Eocene species from the Middle Atlantic Slope are included in this list. ——- Descriptions and illustrations of genera of shells. Proc. Acad. Nat. Sci. Phila., 1872, pp. 50-55. The author describes Latiarca idonea, but gives no locality. Dat, W. H. Contributions to the Tertiary Fauna of Florida, ete. Trans. Wagner Free Inst. Sci., vol. iii, pts. i-v, 1890-1900, pp. 1-947. The biological and geological relations of many of the Maryland and Virginia Hocene molluscan species are discussed. A Table of the North American Tertiary Horizons correlated with one another and with those of Western Europe, with annotations. 18th Ann. Rept. U. S. Geol. Survey, 1898, pt. ii, pp. 325-348. The Maryland Eocene is briefiy discussed. Dana, JAMES D. Manual of Geology (fourth edition), 1895, p. 888. Brief reference is made to the geology of the Middle Atlantic Slope. Darton, N. H. Mesozoic and Cenozoic formations of eastern Vir- ginia and Maryland. Bull. Geol. Soe. Amer., vol. ii, 1891, pl. x, pp. 431-450. The author gives a description of the Eocene deposits of Maryland and Virginia, and designates them the ‘‘ Pamunkey formation.”’ 36 THE EOCENE DEPOSITS OF MARYLAND —— Outline of Cenozoic history of a portion of the Middle At- lantic Slope. Jour. of Geol., vol. ii, 1894, pp. 568-587. The physical history during the Eocene period is briefly referred to, and the relation- ship of the deposits to earlier and later formations is stated. Artesian well prospects in eastern Virginia, Maryland, and Delaware. Trans. Amer. Inst. Min. Eng., vol. xxiv, 1894, pp. 372-379. The lithological character of the strata is discussed and several deep borings are described. ——— Fredericksburg Folio, Virginia and Maryland. U. S. Geol. Survey, Geol. Atlas, folio 13, Washington, 1894. The author describes the Eocene deposits of the area. ——- Artesian Well Prospects in the Atlantic Coastal Plain Region. Bull. 138, U. S. Geol. Survey, 1896, 228 pp., 19 plates. Numerous Hocene sections are given. Nomini Folio, Maryland and Virginia. U.S. Geol. Survey, Geol. Atlas, folio 23, Washington, 1896. The author describes the Hocene deposits of the area. DucateL, J. T. Annual reports of the geologist of Maryland from 1833 to 1841. Annapolis, 8vo. Only brief references to Eocene deposits, and those chiefly of an economic nature, are found scattered through the reports. FEATHERSTONHAUGH, G. W. Geological Report of an examination made in 1834 of the Elevated Country between the Missouri and Red Rivers. Washington, 1835, 8vo, 97 pp. The author refers to the Hocene deposits of Maryland, especially the fossiliferous beds at Fort Washington and correlates them with ‘‘ Lyell’s Eocene.” Fincu, Joun. Geological essay on the Tertiary formations in America. Amer. Jour. Sci., vol. vil, 1824, pp. 31-43. This article contains the first attempt at a differentiation of the ‘‘ alluvial formation ” of the Coastal Plain. The Tertiary is recognized. Frxcu, J. Travels in the United States of America and Canada. London, 1833, 8vo, 355 pp. The author refers to the geology at Fort Washington. Fontainr, W. M. Notes on the Mesozoic strata of Virginia. Amer. Jour. Sci., 3rd series, vol. xvii, 1879, pp. 25-39, 151-157, 229-239. The relations of the Hocene to Mesozoie strata are indicated. MARYLAND GEOLOGICAL SURVEY 37 — The artesian well at Fort Monroe, Va. The Virginias, vol. iii, 1882, pp. 18-19. The Tertiary is regarded as having a thickness of 800 feet. Harris, Ginpert D. Republication of Conrad’s Fossil Shells of the Tertiary Formations of North America. Washington, 1893, Svo, pp. 1-121, pls. i-xx. The republication of Conrad’s important monograph on Tertiary Mollusea, for many years out of print, has rendered it now available to all paleontologists. —— On the geological position of the Eocene deposits of Mary- land and Virginia. Amer. Jour. Sci., 3rd series, vol. xlvii, 1894, pp. 301-304. The Eocene deposits of the Middle Atlantic Slope are correlated by the author with the Bell’s Landing substage of the Lignitic of the Gulf. The Lignitic Stage. Bull. Amer. Pal., vol. ii, No. 9, 1897, pp. 193-294 (1-102), pls. vii-xx (i-xiv), and vol. iii, No. 11, 1899, pp. 1-22, pls. i-xii. Many species found in the Maryland Eocene are described and figured. Haypen, H. H. Geological essay, or an inquiry into some of the geological phenomena to be found in various parts of America and else- where. Baltimore, 1820, 8vo, viii, 412 pp. The general features of the ‘‘ alluvial formation ’’ of the Coastal Plain are described in this volume. HeEILpriIn, A. A comparison of the Eocene Mollusea of the south- eastern United States and western Europe in relation to the determina- tion of identical forms. Proc. Acad. Nat. Sci. Phila., vol. xxxi, 1879, pp. 217-225. Several forms known to oceur in Maryland and Virginia are compared in this article with European species. ——— On the stratigraphical evidence afforded by the Tertiary fos- sils of the peninsula of Maryland. Ibid., vol. xxxii, 1880, pp. 20-33. The author calls attention to the few Eocene fossils in the Maryland strata, and the marked difference between the Eocene and Miocene faunas. ——— Note on the approximate position of the Eocene deposits of Maryland. Ibid., vol. xxxiii, 1881, pp. 444-447. The Maryland Eocene is regarded as ‘‘ nearly equal to that of the Thanet sands of England and the Bracheux sand of the Paris Basin, or of the English Bognor rock (London Clay). It is also correlated with deposits near the base of the ** Bulrstone”’ or possibly even the ‘* Holignitic ’’ of the Gulf. 38 THE EOCENE DEPOSITS OF MARYLAND North American Tertiary Ostreidae. 4th Ann. Rept. U. 8. Geol. Surv., 1882-83, Washington, 1884, pp. 309-316. (Appendix I to C. A. White’s Fessil Ostreidae of North America). Gives Ostrea compressirostra Say (809), O. eversa (310). Contributions to the Tertiary geology and paleontology of the United States. Philadelphia, 1884, 4to, 117 pp. and map. In this volume tke author gives a full discussion of the Eocene deposits of Delaware, Maryland and Virginia. ——w— The Tertiary Geology of the Eastern and Southern United States. Jour. Acad. Nat. Sci., Phila., 2nd ser., vol. ix, 1884, pp. 115-154, map. A monographie study of the formations and a correlation of the different areas among themselves and with those of Europe. Description of Hocene and Miocene forma- tions of Maryland. On some new species of Eocene Mollusca from the southern United States. U. S. Nat. Mus. Proce., vol. iii, 1886, pp. 149-152 and plate. This article contains a description of Crassatella declivis. —- Explorations on the West Coast of Florida. Trans. Wagner Free Inst. Sci., vol. i, 1887. The relation of the Maryland Eocene to that of New Jersey, Alabama, Mississippi and of Europe is briefly indicated (p. 127). Heryricu, O. J. The Mesozoic formation in Virginia. Trans. Am. Inst. Min. Engs., vol. vi, 1878, pp. 227-274. The relations of the Eocene to Mesozoic strata are indicated. Hiecrns, James. Reports of the State agricultural chemist of Mary- land for 1850, 1852, 1853, 1854, 1856, and 1858. These reports contain brief references to the Hocene deposits, chiefly of an econ- omic character. Horcuxiss, JED. Virginia: a geographical and political summary, embracing a description of the State, its geology, soils, minerals, climate, ete. Richmond, 1876, 8vo, pp. iv, 319, and 4 maps. The book contains a description of the Eocene deposits of Virginia, based largely on the earlier observations of Rogers. Kaum, Peter. En Resa til Norra America. Stockholm, 1753-1761, 8°, 3 vols., with English, German, and French translations. This work contains the earliest recorded observations on the geology of the Coastal Plain. co) MARYLAND GEOLOGICAL SURVEY ov Lea, Henry C. Catalogue of the Tertiary Testacea of the United States. Proc. Acad. Nat. Sci, Phila., vol. iv, 1848, pp. 95-107. The author includes in his list the names of the Eocene fossils from the Middle Atlantic Slope. Lea, Isaac. Contributions to geology. Philadelphia, 1833, 8vo, 227 pp. and 6 plates. The Fort Washington deposits are correlated by the author with those of Claiborne, Ala., and a description is given of many forms from the latter locality, some of which have since been found in Maryland. LYELL, CHARLES. On the Tertiary formations and their connection with the chalk in Virginia and other parts of the United States. Proc. Geol. Soc., London, vol. iii, 1842, pp. 735-742. The article contains a description of the James River Eocene deposits, and the im- portance of Venericardia planicosta as a type fossil is discussed. ——— On the Miocene Tertiary strata of Maryland, Virginia, and North and South Carolina. Proce. Geol. Soc., London, vol. iv, 1845, pp. 547-563; Quart. Jour. Geol. Soc., London, vol. i, 1845, pp. 413-429. The author refers to the Eocene in several of the sections that are given. Observations on the white limestone and other Eocene or older Tertiary formations of Virginia, South Carolina, and Georgia. Proe. Geol. Soc., London, vol. iv, 1845, pp. 563-576; Quart. Jour. Geol. Soc., London, vol. i, 1845, pp. 429-442. The author gives a description of the Eocene deposits of the James River, as well as of the Richmond and Petersburg areas. The occurrence of Venericardia planicosta and of a form similar to Ostrea bellovacina of Europe is mentioned. Mac ture, W. Observations on the geology of the United States, ex- planatory of a geological map. Trans. Amer. Philos. Soe., old series, vol. vi, 1809, pp. 411-428. Observations on the geology of the United States of North America, etc. Ibid., new series, vol. i, 1817, pp. 1-92. —— Observations on the geology of the United States of America. Philadelphia, 1817, 8vo, 130 pp. In the publications of Maclure the entire Coastal Plain is referred to the “ alluvial formation.’’ A translation of the first article above mentioned appeared in the Journal de Physique, vol. Ixix, 1809, pp. 204213, and vol. Ixxii, 1811, pp. 187-165, and of the second article in Leonard’s Zeitschrift, Band I, 1826, pp. 124-138. 26 Maury, M. F. Physical survey of Virginia. Richmond, i, 1868, 8 90%pp-; u, 1878, 8>, 142 pp. This publication contains several references to the stratigraphical relations of the Eocene. 40 THE EOCENE DEPOSITS OF MARYLAND McGzE, W J Three formations of the Middle Atlantic Slope. Amer. Jour. Sci., 3rd ser., vol. xxxv, 1888, pp. 120-143, 328-330, 367-388, 448- 466. The author discusses the general features of Coastal Plain stratigraphy, and refers to the contact of the Eocene and Potomac in Virginia. —— Map of the United States exhibiting the present status of knowledge relating to the areal distribution of geologic groups. Fifth Ann. Rept. U. S. Geol. Survey, 1885, pp. 36-38, map as pl. ii. This map, compiled from various sources, shows on a small scale the distribution of the Eocene deposits in the Middle Atlantic Slope. —— The Lafayette formation. Twelfth Ann. Rept. U. S. Geol. Survey, 1892, pp. 347-521, pls. xxxii-xli. The Eocene deposits of the Middle Atlantic Slope are described and the physical history of the formation is pointed out. ——— Geology of Washington and Vicinity. Guide to Washington and its Scientific Institutions, 1891, pp. 38-64; and Congres Géologique International. Compte Rendu, 5me Session, Washington 1891, pp. 219-251, 1893. Article prepared with the collaboration of G. H. Williams, N. H. Darton and Bailey Willis. Contains description of the Eocene by Darton. Miuier, 8. A. North American Mesozoic and Cenozoic geology and paleontology. Cincinnati, 1881, 8vo, 338 pp. Brief general statements regarding the Hocene deposits of the Middle Atlantic Slope are made by the author. Morton, 8. G. Geological observations on the Secondary, Tertiary, and Alluvial formations of the Atlantic Coast of the United States of America. Arranged from the notes of Lardner Vanuxem. Jour. Acad. Nat. Sci., Phila., vol. vi, 1829, pp. 59-71. The attempt is made by the author, in a general way, to delimit more accurately the several formations of the Atlantic Coastal Plain, although at that time the Eocene was not differentiated. ——— Synopsis of the organic remains of the Cretaceous group of the United States. Appendix: Catalogue of the fossil shells of the Tertiary formations of the United States. Philadelphia, 8vo, 1834, 88, 8 pp. (Abst.) Amer. Jour. Sci., vol. xvii, 1835, pp. 377-381. The author gives in his catalogue the Atlantic Tertiary species which had been up to that time described. ——— Additional Observations [to Synopsis]. Philadelphia, 8vo, 1835, 4 pp. The author adds Gryphaea vomer to the Eocene forms from Upper Marlboro and Piscataway. MARYLAND GEOLOGICAL SURVEY 4] Murcuison, R. I. Secondary and Tertiary rocks and superficial de- posits of North America. Proc. Geol. Soc., London, vol. iv, 1843, pp. 127-133. The author reviews the results of Lyell’s investigations upon the Tertiary strata of America, adding his own interpretation of some points. ; Nickues, Joun M., and Basster, Ray 8. A Synopsis of American Fossil Bryozoa. Bull. 173, U. S. Geol. Survey, 1900, p. 72. Upper Marlboro is included in the list of Eocene localities. Prerce, J. Practical remarks on the shell-marl region of the eastern parts of Virginia and Maryland, and upon the bituminous coal forma- tion in Virginia and the contiguous region. Amer. Jour, Sci., vol. ii, 1826, pp. 54-59. Reference is made to the localities at Upper Marlboro, and Potomac Creek. Rocers, W. B. On the discovery of greensand in the calcareous de- posits of eastern Virginia, and on the probable existence of this sub- stance in extensive beds near the western limits of our ordinary marl. Farmer’s Register, vol. ii, 1834. Reprinted in the Geology of the Virginias, 1884, pp. 3-9. The author refers in a general way to the greensand deposits of eastern Virginia, which he compares with similar beds in New Jersey. —— — Further observations on the greensand and calcareous marl of Virginia. Farmer’s Register, May, 1835. Reprinted in Geology of the Virginias, 1884, pp. 11-20. In this publication the author makes the first announcement of the occurrence of the Eocene in Virginia. Report of the geological reconnoissance of the State of Vir- ginia, made under the appointment of the Board of Public Works, 1835. Richmond, 1836, 4°, 52 pp. and plate. Reprinted, Phila., 1836, 8vo, 143 pp. and plate, and in Geology of the Vir- ginias, 1884, pp. 21-122. This report contains a general statement regarding the ‘‘ Eocene Mar] District ”’ of eastern Virginia, with a description of the lithologic character of the strata in the different river valleys. ——W— Report of the progress of the geological survey of the State of Virginia for 1836. Richmond, 1837, 4°, 14 pp. Reprinted, Phila., 1838, Svo, and in Geology of the Virginias, 1884, pp. 123- 145. The Eocene deposits of the peninsula between the Potomac and Rappahannock rivers are described by the author. 42 THE EOCENE DEPOSITS OF MARYLAND —-— Report of the progress of the geological survey of the State of Virginia for 1837. Richmond, 1838, 4°, 24 pp. Reprinted, Phila., 1838, 8vo, and in Geology of the Virginias, 1884, pp. 147- 188. Brief mention is made of the Hocene deposits on the James River. Report of the progress of the geological survey of the State of Virginia for 1839. Richmond, 1840, 8°, 161 pp. Reprinted in Geology of the Virginias, 1884, pp. 245-410. In this report the author describes in much detail the “ Tertiary Marl region south of the James River.’’ B. — Report of the progress of the geological survey of the State of Virginia for 1840. Richmond, 1841, 8°, 132 pp. Reprinted in Geology of the Virginias, 1884, pp. 411-535. This report contains a description of the “ Tertiary Marl region between the Potomac and the Rappahannock rivers,’’ and also of the ‘‘ Tertiary beds in the vicinity of Richmond.”’ — Infusorial deposit of Virginia in the Fort Monroe artesian well. The Virginias, vol. iii, 1882, pp. 151-152. Reprinted in Geology of the Virginias, 1884, pp. 733-736. ; The character of the Eocene strata penetrated in the well-boring is given at various depths. Rogsrs, W. B. and H. D. Contributions to the geology of the Ter- tiary formations of Virginia. Trans. Amer. Philos. Soc., new series, vol. v, 1837, pp. 319-341; vol. vi, 1839, pp. 347-370, 371-377, pls. 26-30. Reprinted in Geology of the Virginias, 1884, pp. 659-673, pls. i-v. The authors describe Nucula cultelliformis, N. parva, and Cytherea ovata from Coggins Point, James River, Ostrea sinwosa from Evergreen, James River, Cucullaea transversa and Venericardia ascia from King George County, Cucullaea onochela and Crassatella capri-cranium from the peninsula between the Potomac and Rappahannock rivers, and Cytherea lenticularis from ‘‘eastern Virginia.” — The same [abstract]. Proc. Amer. Philos. Soe., vol. i, 1839, pp. 88-90. Rurrin, Epmunp. Description of a nut found in Hocene marl. Amer. Jour. Sci., 2nd series, vol. ix, 1850, pp. 127-129. The author describes a nut found in the Eocene marl of the Pamunkey River, Virginia. Say, Tuomas. An account of some of the fossil shells of Maryland. Jour, Acad. Nat. Sci., Philadelphia, vol. iv, 1828, pp. 124-155, pls. 7-13. In this article Ostrea compressirostra is described, but no locality is given. Scnorr, J. D. Beytrage zur mineralogischen Kenntniss des éstlichen Theils von Nordamerica und seiner Gebiirge. Erlanger, 8°, 1787, 194 pp. The author gives the result of his observations in the eastern United States, referring to some of the more striking features of the Atlantic Coastal Plain. MARYLAND GEOLOGICAL SURVEY 4: Ww r ~~ 1CANnY . P - 4 . ») TuomEy, M. Discovery of a chambered univalve fossil in the Eo- cene ‘Tertiary of James River, Virginia. Amer. Jour. Sci., vol. xliii, 1842, p. 187. This article contains some conclusions of the author regarding the stratigraphy of the Hocene, based on a section exposed in a shaft sunk at Evergreen on the James River. Tyson, Puiuip T. First report of Philip T. Tyson, State agricul- tural chemist, to the House of Delegates of Maryland, January, 1860. Annapolis, 1860, 8vo, xi, 145, and 20 pp. and one map. The author describes the Tertiary formations collectively, stating that the work has not progressed far enough to separate the different divisions, although he refers to the WHocene greensand marl. ——— New topographical atlas of the State of Maryland, ete. 1873. This work contains a general statement regarding the geology of Maryland, including a description of the Eocene. Unter, P. R. Observations on the Eocene Tertiary and its Creta- ceous associates in the State of Maryland. Trans. Maryland Acad. Sci., vol. i, 1888, pp. 10-32. ——-— Additions to observations on the Cretaceous and Eocene for- mations of Maryland. Trans. Maryland Acad. Sci., vol. i, 1889-1890, pp. 45-72. Notes and illustrations to * Observations on the Cretaceous and Eocene formations of Maryland.” Trans. Maryland Acad. Sci., vol. i, 1890, pp. 97-104. The above articles contain an extensive description of the Eocene and a discussion of its relations to the Cretaceous. Van RENSSELAER, J. Lectures on geology, New York, 8°, 1825, 350 pp. The author accepts the conclusions of Finch regarding the so-called ** Alluvial forma- tion,”’ and describes briefly the Tertiary formations of the Northern Atlantic Coastal Plain. VaueHan, T. WAyLtaNb. Contributions to the Eocene Fauna of the Middle Atlantic Slope. Coelenterata. Johns Hopkins Univ. Cire., 1895, vol. xv, p. 6. The author describes Paracyathus (2?) clarkeanus and Turbinolia acuticostata from Potomac Creek. : The Eocene Deposits in the Middle Atlantic Slope in Dela- ware, Maryland and Virginia. Coelenterata. Bull. 141, U. S. Geol. Survey, 1896, pp. 89-91. The same forms are described as in the above article. — Eocene and Lower Oligocene Corals of the United States. Monograph U. S. Geol. Survey, No. xxxix, Washington, 1900. The author describes in much detail the coral species from Maryland and Virginia. t4 THE HOCENE DEPOSITS OF MARYLAND GENERAL STRATIGRAPHIC RELATIONS. Our knowledge of the Tertiary geology and paleontology of the Middle Atlantic Slope has been largely increased since the days of Conrad and Rogers, yet few fields have afforded better opportunities in recent years for continued investigation, since very divergent opinions have prevailed and even to-day find expression in the different interpretations of the data. Both the Eocene and the Neocene divisions of the Tertiary in this area have broad surface exposures, and are represented by character- istie sections along the leading waterways. Both are also highly fossilf- erous, although the Neocene shows a greater diversity of species than does the Eocene. This difference, however, is not so great as one would infer from a perusal of the literature, since a large number of Eocene species, many of them very common, have been until recently unrecog- nized, or at least unrecorded. A brief discussion of the general relations of the Coastal Plain de- posits i the Middle Atlantic Slope is essential to a clear comprehen- sion of the Eocene formations. A more detailed history of the several eroups of deposits will be found in other volumes of the Survey. The Coastal Plain consists geologically of a series of formations that were deposited as moderately thin sheets, one above another, along the eastern border of the crystalline belt, elsewhere referred to as the Pied- mont Plateau. The coastal deposits are shghtly inclined eastward, so that successively later members of the series are encountered in passing from the interior of the country toward the coast. From the beginning of deposition in the coastal region until the pres- ent time sedimentation has apparently been constantly in progress over some portions of the area. Differential movements of the sea-floor, with its accumulated sediments, took place, however, from time to time, so that the formations present much complexity along their western mar- gins. It is not uncommon there to find certain members of the series Jacking, as renewed deposition carried a later formation beyond its pre- decessors. In the absence of distinctive fossils, the discrimination of the different horizons at such points is often attended with great un- certainty. MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE il. Fig. 1.—FARM- AND WOOD-LAND ALONG SOUTH RIVER. n Fig. 2.—FARM-LAND NEAR ANNAPOLIS WATER WORK VIEWS! OB SURFACE OF EOCENE COUNERY- MARYLAND GEOLOGICAL SURVEY 45 Deformation has also affected the region to a limited extent, the strata being slightly warped, so that the plane of bedding does not main- tain a uniform strike and dip. This is particularly marked along the western border of the area. There have also been slight displacements in various localities. McGee" has described one of these, while others have been observed by the junior author of this report. It seems highly probable that every geological period from the Creta- ceous (possibly Upper Jurassic) to the Pleistocene is represented, al- though in one or two instances the lack of characteristic fossils renders the taxonomic position of certain formations difficult of absolute deter- mination. CRETACEOUS. The Cretaceous (in part possibly Upper Jurassic) is extensively repre- sented in the Middle Atlantic Slope. The deposits of this period con- _ sist of a series of basal formations that has been designated the Potomac group, comprising the Patuxent, Arundel, Patapsco and Raritan forma- tions, none of which was deposited under marine conditions, overlain in succession by the Matawan, Monmouth, and Rancocas formations, which are distinctly marine in origin. All but the Potomac formations gradu- ally disappear southward, that group alone of the Cretaceous deposits being recognized in Virginia. Unconformities characterize the several members of the Potomac group while the marine deposits are also un- conformable to the older strata. The Potomac group consists chiefly of sands and clays, the former frequently arkosic, with gravel at certain points where the shore accu- mulations are still preserved. The deposits of the Patuxent formation are highly arkosic, the sands and clays showing both a vertical and a horizontal gradation into one another. The sand layers are seldom widely extended, being generally lenticular masses, which rapidly dimin- ish in thickness from their centers. Dark colored clays abound in the Arundel formation and have yielded large amounts of nodular carbonate of iron. Highly colored and variegated clays largely make up the Patapsco formation. Thick-bedded and widely extended white sands 17th Ann. Rept., U. 8S. Geol. Survey, pp. 616-633. 46 THE EOCENE DEPOSITS OF MARYLAND with interstratified clays characterize the Raritan formation. The fos- sils consist chiefly of the bones of dinosaurian reptiles and of leaf im- pressions, the former confined to the Arundel formation, the latter pre- dominating in the Patapsco and Raritan formations. The plants show beyond a doubt the Cretaceous age of the two upper formations while the reptiles have been regarded by high authority to be upper Jurassic. The Matawan formation is formed largely of fine sands and clays, clearly stratified, and in the case of the clays often laminated. The clays and sandy clays are generally dark, often black, in color. They are commonly micaceous, and at time sparingly glauconitic. The very homogeneous and persistent character of the beds is in marked contrast to the deposits of the Potomac group which they overlie. The fossils consist largely of marine Mollusca which indicate the upper Cretaceous age of the deposits. The Monmouth formation consists chiefly of greensand deposits, although the glauconitic element is not so pronounced or so persistent south of the Chesapeake as in the more northern districts. The strata “are more arenaceous, and as a result the materials weather more readily, showing generally in greater or less degree the characteristic reddish color of the hydrated peroxide of iron. ‘The common and characteristic Gryphaea vesicularis, Exogyra costata, and Belemnitella americana are widely found, with other typical forms. The Rancocas formation is also largely composed of greensands, gen- erally more glauconitic than the Monmouth formation, although at times somewhat argillaceous. The strata are much weathered where exposed, and often appear as a firm red rock, the grains being cemented by the iron oxide. The deposits have afforded Terebratula harlani, Gryphaea bryant, and other characteristic species of the New Jersey area. EOCENE. The Eocene is represented in the Middle Atlantic Slope by a group of deposits stretching along the eastern margin of the Coastal Plain and overlying the Cretaceous formations unconformably. They will be described in much detail in the following pages. The deposits consist largely of greensand marls, which may, how- MARYLAND GEOLOGICAL SURVEY 17 ever, by weathering, lose their characteristic green color, and by the deposition of a greater or less amount of hydrous iron oxide become firm red or brown sandstones or incoherent red sands. At times, notably in Southern Maryland and Virginia, the strata become highly argilla- ceous, the glauconitic elements largely or quite disappearing. Infre- quently coarse sands and even gravels are found, the latter chiefly toward the base of the formation and near the ancient shore line, especially toward the northeast in central and eastern Maryland. Very commonly the shells of organisms are so numerous as to form the chief constituent of certain beds. Notwithstanding these facts, the deposits are remarkably homogeneous, although recent investigations have shown the possibility of dividing the deposits into two well-marked formations on both lithologic and faunal grounds. The lower or Aquia formation is much more highly arenaceous than the upper or Nanje- moy formation which, particularly in its lower part, is generally highly argillaceous. The Aquia formation is also much more calcareous than the Nanjemoy formation, indurated layers frequently appearing in the former. NEOCENE. The Neocene deposits occupy the region to the southeast of and over- lie the Eocene. The lower beds comprise the Chesapeake group, so named from the superb sections found exposed on the shores of Chesa- peake Bay, and recognized to consist of three well-defined formations; the upper beds comprise the Lafayette formation. The Neocene de- posits lie unconformably upon those of the. Eocene and overlap them along their western border, where they ultimately come to rest upon the Cretaceous toward the northeast. They are in turn unconformably overlain by the Pleistocene deposits. The Chesapeake group consists of sands, clays, marls, and diatomace- ous beds. The latter, composed almost exclusively of the tests of dia- toms, are chiefly confined to the lower portion of the basal formation, where they afford striking, light-colored bluffs along many of the larger stream channels. The nearly pure diatomaceous earth reaches a thick- ness of 30 or 40 feet, although the remains of diatoms are found scat- tered in greater or less amounts throughout much of the overlying strata. 48 THE EOCENE DEPOSITS OF MARYLAND The greater portion of the Chesapeake, however, is composed of variously colored sands and clays, with which are frequently mingled vast numbers of molluscan shells. Sometimes the shelly materials form so large a proportion of the deposits as to produce nearly pure calcareous strata, which in a partially comminuted state may become cemented into hard limestone ledges. The organic remains are very numerous and show the Neocene age of the deposits. ‘Their great number early attracted the attention of geologists, in whose writings descriptions of them are frequently found. Several faunas have been distinguished on the basis of which, as well as on stratigraphic and structural grounds, a number of well-defined formations have been recognized by the State Geological Survey. Covering the Chesapeake deposits in places, is a formation composed of gravel, sand, and clay, which thus far has afforded no distinctive fossils upon which to base a determination of its geologic age. From the fact that the deposits rest unconformably upon the underlying Chesapeake, and are in turn unconformably overlain by the Pleistocene, they have been thought to represent the late Neocene or Pliocene. The apparent similarity of these deposits to those in Mississippi, des- eribed by Hilgard under the name of the Lafayette formation, has led to the adoption of the same name for the strata of the Atlantic Coast. The beds of the Lafayette are very irregularly stratified, and often change rapidly within narrow limits. ‘Toward the ancient shore-line the deposits are of coarse gravel, through which is scattered a light-colored sandy loam, the whole cemented at times by hydrous iron oxide into a more or less compact conglomerate. The eastward extension of the formation shows a gradual lessening of the coarser elements and a larger admixture of loam. Arkosic materials are also present throughout the formation, while the coloring and manner of weathering are highly characteristic, the exposed surfaces presenting what is known as case- hardening. PLEISTOCENE. Superficially overlying the deposits hitherto described, and with marked variations in thickness, composition, and structure, is the Pleis- tocene, which lies at various elevations from near sea-level to 200 feet MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE lil Fig. 2.—BLOCKS OF ZONE 9, LARGELY COMPOSED OF TURRITELLA MORTONI. VIEWS OF EOCENE SECTIONS. MARYLAND GEOLOGICAL SURVEY 49 in the different portions of the region. From its typical development in the District of Columbia all the Pleistocene deposits of the Middle Atlantic Slope received the name of Columbia formation by McGee who described three distinct phases, viz., the fluvial, the interfluyial, and the low-level. Later Darton recognized high-level and low-level phases which he called earlier and later Columbia. More recently Shattuck, of the State Geological Survey, has shown that greater complexity ex- ists in the Maryland Pleistocene deposits than had been before recog- nized, and that the later Columbia will have to be further divided, at least locally. The Pleistocene deposits consist of gravel, sand, clay and loam, the materials in general becoming finer and more fully stratified with distance from the old shore-line and river-channels. In the latter instance they at times contain large numbers of marine molluscan shells, forming a characteristic calcareous marl. In general, howéyer, the or- ganic remains consist largely of the branches and leaves of terrestrial lants, many of which are exquisitely preserved. > ) | 4 DISTRIBUTION OF THE STRATA. The Eocene strata of the Middle Atlantic Slope form a belt of varying width, extending from northeast to southwest, somewhat to the west of the center of the Coastal Plain. This belt has been traced almost con- tinuously from the southern portion of Newcastle county, Delaware, to the valley of the Nottoway river, in southern Virginia. Although at times buried beneath later deposits, the Eocene presents fine exposures along all the leading stream-channels, while not infrequently broad outcrops of the formation appear at the surface in the intervening country. DELAWARE, In Delaware the Eocene is found apparently only near the Maryland line and slightly to the south of the central portion of Newcastle county, where it occupies a restricted portion of the country between Appoquini- mink Creek on the north and Old Duck Creek on the south. Toward Delaware Bay the formation entirely disappears, the Neocene resting directly upon the Cretaceous. Even in the limited area where found 4 50 THE EOCENE DEPOSITS OF MARYLAND the Neocene deposits widely cover the Eocene, so that in the absence of large streams satisfactory exposures of the strata are not found. MARYLAND. In eastern Maryland the conditions of outcrop become more favorable, although the Neocene deposits still cover the higher portions of the country while the Pleistocene beds often fill the valleys and cover the lowlands adjacent to the Bay. Several fine sections are found in the drainage basin of the Chester river in both Kent and Queen Anne’s counties, the width of outcropping beds broadening from a few miles at. the boundary to more than 10 miles in some places, and reaching quite to the valley of the Sassafras river. On the western side of the Chesa- peake the Eocene is much more extensively developed than upon the eastern, and covers wide areas in Anne Arundel, Prince George’s, and Charles counties. In Anne Arundel county the best sections are found along the Severn and South rivers and their tributaries. The highland forming the neck below the lower Magothy and Severn rivers is largely composed of Eocene beds, the most western exposure being found at Mount Misery, near Round Bay, Severn river, at an altitude of 100 feet, while eastward it reaches to water-level. The higher portions of the area between the Severn and South rivers are also largely made up of Eocene deposits, as is also the land to the southwest of the latter stream and between it and the valley of the Patuxent river. Throughout the southern portion of the county the Eocene is, however, capped by the Neocene and Pleisto- cene formations along the central highland. Much of the western-central portion of Prince George’s county is com- posed of Eocene strata, many fine sections occurring along the western branches of the Patuxent river. Along the Potomac the strata are found in numerous bold bluffs, while broad exposures appear in the valleys of many of the larger tributaries, notably in Piscataway and Mat- tawoman creeks. Upper Marlboro, on the eastern side, and Fort Wash- ington on the western side of the county are among the best known localities for Eocene fossils in the Middle Atlantic Slope. In Charles county the Eocene is confined to its western half, fine sec- MARYLAND GEOLOGICAL SURVEY 51 tions being found at Clifton Beach, along Port Tobacco River, and at Popes Creek. Since the deposits are in general at lower levels than in Prince George’s county, on account of the easterly dip of the beds, the surface outcrops are largely covered by the Neocene and, Pleistocene formations. VIRGINIA. The most complete section of the Eocene in the whole Middle Atlantic Slope is afforded by the series of high bluffs on the western bank of the Potomac river between Aquia Creek and Mathias Point, in eastern Staf- ford and northern King George counties. The peninsula between the Potomac and Rappahannock rivers is to a large extent formed of the Eocene greensands, which also appear in places along the banks of the latter stream, outcropping beneath the Columbia formations. The higher levels of the intervening country are generally capped by the Neocene formations. Southward the Eocene deposits are continued in eastern Spottsyl- vania and in Caroline counties. Fine bluffs of the characteristic marls appear on the south bank of the Rappahannock at several points above Port Royal, but in the valley of the Mattapony they are much less prom- inent, although occurring at frequent intervals. An extensive cover of Neocene deposits occupies the higher portions of the country. In the valley of Pamunkey river and its tributaries, particularly in Hanover county, important outcrops of the Eocene are found. Many of the fossils described by Conrad and Rogers were obtained from this area. Farther south, in the valley of the James river, are many of the most notable occurrences of the Eocene in the whole region. At Richmond, City Point, Evergreen, and Tar Bay prominent exposures are found, the two latter localities particularly being rich in organic remains. At Petersburg and vicinity the Eocene is exposed in the valley of the Appo- mattox, but the sections are in the main poor. South of Petersburg the only exposure so far as known is at Bolling’s Bridge, on the Nottoway river. 52 THE EOCENE DEPOSITS OF MARYLAND GENERAL CHARACTER OF THE DEPOSITS. COMPOSITION. The Eocene deposits of the Middle Atlantic Slope are typically glau- conitic, and are found in their unweathered state either as dark gray or green sands or clays. The glauconite varies in amount from very nearly pure beds of that substance to deposits in which the arenaceous and argillaceous elements predominate, although the strata are generally very homogeneous through considerable thicknesses. At certain hori- zous the shells of organisms are found commingled with the glauconitic materials in such numbers as largely to make up the beds, producing what is known as a greensand marl. These beds are at times so indu- rated as to form true limestone ledges. This latter phase is seen typi- cally developed both at Fort Washington and Aquia Creek, interstrati- fied with the unconsolidated greensand layers. When the glauconite is weathered the deposits lose their character- istic gray or green color and generally become lighter gray with reddish or reddish-brown streaks or bands, or may be entirely of the latter color. This change to red beds particularly characterizes the Eocene deposits of the northern portion of the area, from the Patuxent valley to the Delaware hne. Throughout much of this territory the beds are coarse sands and become predominently so toward the northeast. This type of material is well seen on Mount Misery on the north bank of the Severn river and at various points on the Chester river, where it is often ce- mented into a ferruginous sandstone. In the less completely weathered portions of the formation farther south the change is indicated by the mottled yellow and brown appearance of the more superficial beds, many of the glauconitic grains still showing their green color when crushed. Thin iron crusts at times appear in strata of this character. It is noteworthy that in the northern portion of the area the cement- ing medium of the indurated beds is either ferruginous or siliceous while in the southern portion it is chiefly calcareous. When the glauconite is largely or, more rarely, entirely absent in the original materials, the deposits consist of black or gray sands or clays, the latter at times micaceous, and in a few instances carbonaceous. A microscopical examination of several selected specimens from dif- MARYLAND GEOLOGICAL SURVEY 53 ferent portions of the area shows that the land-derived elements of the deposits are mainly quartzose, quartz grains predominating. Fragments of crystalline rocks occur, while numerous constituent and accessory minerals derived from them are found. Chemical analyses of several typical specimens, made by Mr. Peter Fireman, of Columbian University, give the following results: ANALYSES OF MARLS. NANJEMOY. AQUIA, lis He IIl. Woodstock, Aquia Creek, Winchester. OLD reper eneh sical fc dayaccsciernisna lees 60.87 21.58 49.08 Bae Oe hes Oday icitia sas «oe, 22.68 7.70 41.25 AU STOY, eee Pesen a ee ee Pe Pes Org 1.05 76 CaO ers eoiotas ie noone 1.66 36.78 None. SIN Op re ei reneia witia eiiave ress okt 17 Light greenish-gray greensand, with Twrritella mortoni, Cucullaea gigantea, Crassatellites alaeformis, Ostrea com- pressirosira, etc., - - - - - - - - - - 30 Greensand, with fragments of shells of lower beds, - - - Greensand, with corals, = Ind. greensand, with Pholadomya marylandica, & Phenacomya: petrosa, Greensand ai pea— spit ace a et ow 9 rai ee, eo ee Induratedvereensand, =" (== = = 8-9 = = = = = oon=*N Dark greensand with many fossils, including Dosiniopsis lenticularis, Meretrix ovata var.pyga, Crassatellites alae- Jormis, and Ostrea compressirostra, - - - - - - 18 Greensand, at times argillaceous, =Uegcoyee sas ay ae =o" f= 30 EOCENE, PLATE V ZONE 16 15 10 op AON SCALE 40 FEET=-1 INCH Woodstock Member Potapaco Member Paspotansa Member Piscataway Member Nanjemoy Formation Aquia Formation GENERAL COLUMNAR SECTION OF EOCENE STRATA IN MARYLAND MARYLAND GEOLOGICAL SURVEY 65 Other species are restricted to one or the other of the substages of the Nanjemoy and are mentioned beyond. Additional to these are the forms previously referred to as found in both divisions of the Pamunkey group. THE POTAPACO MEMBER OR SUBSTAGE, The Potapaco member, so-called from the early name of Port Tobacco Creek, which is a corruption of the word Potapaco found on the Smith and other early maps, is composed of greensand, often very argillaceous and at times gypseous. The clayey character of the member, especially in the lower bed, is in marked contrast to the more highly glauconitic nature of the Aquia formation. The thickness of the member is about 60 to 65 feet. The Potapaco substage embraces Zones 10 to 15. The following species are restricted in range to it: Cypraea smithi Aldrich. Periploma sp. Solen lisbonensis Aldrich. Ceriopora micropora Goldfuss. (?) Lucina astartiformis Aldrich. The following zones constitute the subdivisions of the Potapaco in the Potomac area, some of which can be recognized over wide areas: Zone 10.—The greenish-gray sand which overlies the Turritella rock is more argillaceous than the underlying or overlying beds of the Eocene. The glauconite grains have been much weathered and nearly all trace of the shell substance has been removed from the few forms recognized. To the northeast of the Potomac area, throughout the central portion of Southern Maryland, this bed becomes a well-defined clay, as at Upper Marlboro, and has been referred to as the Marlboro clay. The casts found at the Potomac Creek bluff are chiefly those of a Meretrix, prob- ably Meretrix ovata var. ovata. An indurated layer, near the middle of the zone, contains Calyptraphorus trinodiferus; below this is the repre- sentative of the red clay which occurs typically about Upper Marlboro. No fossils were observed at the Aquia Creek bluff. The bed is about 25° feet in thickness. Zone 11.—This zone is composed of a thin, indurated layer of argil- laceous greensand, 1 to 2 feet in thickness. It is well developed at the Potomac Creek bluff, where it contains Venericardia potapacoensis, and is the lowest horizon at which this species has been found. 5 66 THE EOCENE DEPOSITS OF MARYLAND Zone 12—A greenish-gray argillaceous sand, containing few un- - weathered grains of greensand. No fossils have been found init. The bed is 8 or 9 feet thick. Zone 13.—This bed consists of a light-gray glauconitic sand, generally somewhat weathered. It is crowded with shells of Venericardia potapa- coensis, and also contains Tornatellaea bella, Cadulus abruptus, etc. It is 3 feet in thickness. Zone 14.—Overlying the Venericardia layer is a bed of greenish-gray argillaceous sand, some 4 to 6 feet in thickness, that contains a great number of bands filled with gypsum crystals. No fossils were observed. Zone 15.—This bed consists of greenish-gray argillaceous sand, in which the glauconite grains have often been extensively weathered. The bed has a thickness of 12 to 25 feet. At various localities in Charles county, notably about Port Tobacco and at the headwaters of Nanjemoy Creek, this zone contains a fauna that is quite distinct from either the Aquia or Woodstock faunas. It is an unweathered greensand, and very argillaceous at these localities. The top of the bed is marked by a well-developed layer of concretions. This layer passes below water-level about 24 miles above the mouth of Popes Creek, and is to be seen about six feet above the base of the bluff at Woodstock. . THE WOODSTOCK MEMBER OR SUBSTAGE, The Woodstock member, so-called from Woodstock, which is an old estate situated a short distance above Mathias Point on the Virginia bank of the Potomac, is characterized by fine, homogeneous greensands and greensand marls, that are less argillaceous than the underlying Potapaco beds. The member has a thickness of 50 to 60 feet. The Woodstock substage embraces Zones 16 and 17 and contains the following species in addition to those previously mentioned as ranging throughout the Nanjemoy, viz.: Carcharodon auriculalus (Blainville). (7) Leda parilis Conrad var. Galeocerdo latidens Agassiz. Spiroplecta clarki Bagg. Olivula sp. Nodosaria affinis (Vv Orbigny). Levifusus trabeatus (?) Conrad. Cristellaria radiata Borneman. Levifusus trabeatus (?) var. Polymorphina austriaca (WV Orbigny). Pyrula penita Conrad. var. Polymorphina elegantissina Parker & Jones. Pyrula sp. Polymorphina praelonga Terquem. MARYLAND GEOLOGICAL SURVEY 67 Turritella potomacensis Clark and Martin. Globigerina bulloides WOrbigny. Dentalium minutistriatum Gabb. Discorbina bertheloti (VOrbigny). Meretrix lenis (Conrad), Pulvinulina schreibersii (WV Orbigny). (¢) Meretric subimpressa (Conrad). Nonionina affinis Reuss. (7) Lucina astartiformis Aldrich. Amphistegina lessonii VW Orbigny. Venericardia marylandica Clark & Martin. Carpolithus marylandicus Nollick. Modiolus marylandicus Clark and Martin. Carpolithus marylandicus var. rugosus Leda parva (Rogers). Hollick. The two zones comprising the Woodstock in the Potomac area are characterized as follows: Zone 16.—In this zone have been placed the strata intervening be- tween the upper layers of the Potomac Creek section and the base of the Popes Creek section. The deposits are estimated to reach about 40 feet in thickness, and are chiefly greensands and greensand marls. They appear in an unfossiliferous condition in some of the ravines to the west of the Woodstock area, and along the shores where they contain a few fossils of common Woodstock species. Zone 17.—The highest beds at Woodstock, and the Popes Creek strata, are grouped together in this zone. The materials are very homo- geneous, although several inconstant indurated layers appear. The thickness of this zone is about 20 feet. A thin bed of Ostrea sellaeformis was observed in the lower part of the zone, although evidently not always at the same horizon. Otherwise, so far as observed, the fossils are the same in the several parts of the two sections. The most common forms are Protocardia lenis, Glycymeris idoneus, Meretrix subimpressa, Corbula subengonata, Corbula oniscus, Leda cultelliformis, Pecten dalli, Leda improcera, Leda parva, Nucula potomacensis, Lucina dartoni, Lucina uhleri, Lucina whitei, and Ringicula dalli. LOCAL SECTIONS. The formations and faunal stages previously described are based on the numerous local sections found scattered throughout the Eocene area of Maryland. The most numerous and complete series of sections is found in the valley of the Potomac river, but other and highly im- portant sections are found to the northward nearly to the Delaware line. Potomac River Section. The most complete section of the Eocene deposits of the Middle Atlantic Slope is found in the valley of the Potomac river between Aquia 68 THE EOCENE DEPOSITS OF MARYLAND Creek, Stafford county, Va., and Popes Creek, Charles county, Md. Throughout this distance the bluffs afford a nearly complete sequence of the several beds of the formations, while the fossils are numerous and well-preserved. , The full Potomac Eocene series is given in both generalized and local columnar sections on Plates V and VI. The former is made up chiefly from the local sections afforded by the biuffs at Glymont, Aquia Creek, Potomac Creek, Nanjemoy Creek, Woodstock, and Popes Creek, but con- tains additional data cbtained at a few points inland. The local sections are presented in columnar form on Plate VI, and the numbering corresponds with that given at the head of the deserip- tions of the sections which follow. The numbering of the zones in the general section is the same as that in the local sections. The unnum- bered zones are pre- or post-Eocene, as the case may be. I. Section at Glymont, north of wharf and ravine. Feet Pleistocene. Grayelvand Vox mie. ntl sie eeeet ie eee eer ee ee 20 f Light green glauconitic sand, underlain by argillaceous sand with few fossils /(Zone 4). serie eee ee ies - 10 ie indurated ereensandi(ZOne (3) Gas eee eee ee 1 . = | Greenish marl with numerous fossils including Ostrea com- E = = pressirostra, Crassatellites alaeformis, Turritella mortoni, ocene. oe ae a Eman: a peieat : a3 Dosinopsis lenticularis, Meretrix ovata var. pyga, ete. “ @ (ZONED) on tes o/s oc als Sees he es ee Ee EE: 21 & | Argillaceous glauconitic sand for the most part without fossils, but containing indeterminate plant remains and {| mollusean casts at the base (Zone 1).................-.-- 8 Cretaceous. Varierated clays of the Potomac group.........-......... 20 ROEAD. so) Ns yo ted Se: 5 ecarcene e Costes ho elma oh eee ena oe keer 80 Il. Section two miles up Aquia Creek. Feet Pleistocene. Gravelvand sand’) 2. ted <2 12 osisngee ei cias) eke eee Een 7 pS if ; 5 | indurated greensand (Zone 3)..-..........-.-----....0e-- i - & , Greensand with characteristic fossils (Zone 2)............. 15 Eocene. a+ 4 5 s ? ies =e A E = = | Argillaceous sand more or less glauconitic without fossils Sa (ZOMG) oo Sisicate nt a =sortantlen nae eRe eer 18 Tobalies Fein foe die creeks oteret ote he eaera icy os eee eee 41 MARYLAND GEOLOGICAL SURVEY EOCENE, PLATE VI LEGEND [i] Nanjemoy Formation Aquia Formation The Numbers \ to X correspond to those used in the chapter on ‘‘Local Sections” The Numbers 1 to 17 correspond to those used in the chapter on ‘The Formations and Faunal Stages’’ SCALE 40 FEET—1 INCH IX Vi pace $ 2 2 - 2G Pag OL A) de ca 7 Takoe a - 2 2 ras Pr) soa Be pe Se Z 15 U- y 1- : Joss seossasasgood = $< -------------- 5 GLYMONT POPES CREEK 2.5 MILES WOODSTOCK 8 MILES ABOVE HEAD OF 8 MILES BELOW MOUTH OF MOUTH OF Kenamantee ABOVE POPES CREEK NANJEMOY CREEK POTOMAC CREEK POTOMAC CREEK AQUIA CREEK POPES CREEK DETAILED COLUMNAR SECTIONS OF EOCENE STRATA IN THE POTOMAC VALLEY A.HOEN & CO, BALTIMORE Pleistocene. I Eocene. = o = Pleistocene. Neocene. ay ° q o ‘™ {=| 3S Z, Eocene. S = a < ee en aS Paspotansa. MARYLAND GEOLOGICAL SURVEY 69 III. Section of western portion of bluff at Aquia Creek. Feet. Fine sand, light-yellow in color, with white clay near the DEIR Gatorerersrieteralccctancraretstonerel ct ee cetarvictaceie™ale aupinidi eislareiayerm e’ala @ ahi 26 f Fine sand, of light-greenish color, containing a few glanu- COUN Geordie (AOUG HO)... (7 aemivis's a= ie sins udu eeiehs x on ase 10 Be | Thick-bedded, arenaceous, and glauconitic limestone inter- 2 stratified with unconsolidated layers of partially weathered Ss greensand, the indurated layers largely filled with the = shellsof Dinwitella mortont (Zone 9)... 2.5.2 2..e...nccese 10 i Fine sand, of gray or green color, containing several Ay irregular bands of Yurritella mortoni, also T. humerosa, Cucullaea gigantea, Crassatellites alaeformis and Ostrea com- VORESSUROSENGN (OU Gee) Wrelatcuctetarataheyayene eye aeetette et el ate relevevererey™ eter inrs 30 ( Dark-colored greensand, chiefly filled with broken shells of Meretrix ovata var. pyga and Crassatellites alaeformis (Lonet) 7 Ditto, with same shells in whole condition (Zone 6)....... i Indurated layer of light-colored greensand filled with ca Turritella mortoni, T. humerosa, Crassatellites alaeformis, = Dosiniopsis lenticularis, Meretrix ovata var. pyga, Panopea S } elongata, Pholadomya marylandica (Zone 5).............- 2 S Greensand marl containing same forms (Zone 4)........... 8 rs Indurated layer of dark-colored greensand with Crassatellites alaeformis, Meretrix ovata var. pyga, Dosiniopsis lenticularis, and Ostredecompressvrosird. (LONEGno)yitaierelatol-)=) eerste a yeas 2 Greensand marl with Dosiniopsis lenticularis, Meretrix ovata | var. pyga and Crassatellites alaeformis (Zone 2)..........- 16 TOW sosoic vo ode cou ding oh SHO OO MOB Ub UO OD Oba TadobODUCS 112 IV. Section of center of bluff at Potomae Creek. Feet Fine yellowish sand containing red and brown bands ...... 15 White gritty clay, with Miocene fossils at base............ 5 ( Greenish-gray argillaceous sand, slightly glauconitic (Zone 15) ob So comas so oN emcee Doo SroorMoE coop oa oberooe OSS 38 Argillaceous sand containing bands of selenite crystals S (LONG Was ces eoacocu Ae USO RH oe Oneo PONS nOnnoU soar 4 s | Light-gray glauconitic sand with Venericardia potapacoensis AIM (Zorie 18) Penge ete ee eee athe os 3 So | Greenish-gray argillaceous sand (Zone 12)................. 8 * | Indurated greensand with Venericardia potapacoensis(Zone1l) 1 Greenish-gray argillaceous sand, glauconitic, with casts of Wea (AONE NO)s osc cacbcosscoecpocoode basdcnso0GC 25 Thick-bedded arenaceous and glauconitic limestone inter- stratified with layers of partially weathered greensand, the indurated strata largely composed of the shells of Sh PMCANKT) WODREOOE (AON 8) 3 Gascon scons O° Sorc nooGudoUGe 12 Greensand bed, much weathered in its upper portions, and filled chiefly with Turritella mortoni in several thick layers; also T. humerosa, Cucullaea gigantea, Crassatellites alaeformis, | Ostrea compressirostra, and many other species (Zone 8)... 29 — AL, — THE EOCENE. DEPOSITS OF MARYLAND V. Section three miles below Potomac Creek. Feet. Pleistocene. SHHAO RCM NC REA ab a Geinde codudoce tude OU oulH aa dooanAenauT oe 2 ( Greenish-gray argillaceous sand (Zone 15)... ............. 4 cS 9 a dated argillaceous sand with gypsum erystals (Zone : ne ete! a Ie net Me NON RO Ac Oo aoe Ac Mama A cin eciin Eocene. & & ~ Light gray greensand with band containing Venericardia. as VOOM TURD ADS VANS) mogdo aca codassecee bso odoamgeddes 4 ZB Greenish-gray argillaceous sand (Zone 12)................. 10 | Indurated greensand with Venericardia potapacoensis(Zone11) 1 PROG AN eats eect © re, bcs ierenataue Ssct et ere creates crete ck ieee ene neice 26 VI. Section at Head of Nanjemoy Creek. Feet Pleistocene. San deamd owavieli nc casussie sieve citar trees acoso ate sere 4 6 [ Greenish-gray argillaceous sand with layers containing : Seong Venericardia potapacoensis (Zone 15)...............------ ial fs J POR Re Eocene. 2s By) Light gray greensand with gypsum beds (Zone 14)......... 6 s L Light gray greensand with Venericardiapotapacoensis(Zone13) 3 7 AH Covered OP LAS Keyan creecina wer Ome otro ce etoleaG aly ah QB SA tee omic 75 TS OT Be ee cone tata taleeee swim evare. eee ths sre aver oreuere tee ege one ntey toner Perel 99 VII. Section three miles above Popes Creek. ‘ : Feet Pleistocene. Greeny HNC SANE Soe oheownedcsoe SucuDtUoesoooMCbOoCOuESS 35 Ee nl eee : 2 § Arcillaceous oreensand (Zone 15)) 22 seenecm ene. seen oe 6 d 3 : e Eocene. o & { Greensand with gypsum crystals (Zone 14)........... a) ; a+ | = iS) RL ald & * CMON Gtr don yest eke ats ote nee archaea ee 14 VIII. Section two and one-quarter miles above Popes Creek. eA eet. Neocene. IDTENOMMRCEOUE GARIN soccse coeds cocdossooeesa eH aO ee 10 t (sz | ( Greensand with fossil casts (Zone 17) ...........-------«: 10 S | iS g | Greensand, somewhat argillaceous (Zone16)............... 30 iS n BU S8uE: ae _ ¢ ( Grayish black argillaceous greensand (Zone 15) with num- Ss || 2 = erous bands of Venericardia potapacoensis and other fossils, Se | overlaid by a band of concretions 5) (= Soh eee, ee vets 8 le) ele) em ee oe7 te erm MOM scatestosSonoseoanscocde dees oodsedodgswoseods Bb) IX. Section of center of bluff at Woodstock. Feet. Pleistocene. Yellow and orange-colored sands and gravel .............- 25 Neocene. Diatomaceous earth with Miocene fossils ............- sane 5 ( .; ¢ Argillaceous greensand (Zone 17) ................----5-5- 6 > | Dark greensand more or less argillaceous with JMZitra potoma- = | censis, Strepsidura subscalarina, Turritella potomacensis, SS oS : Mesalia obruta, Corbula oniseus, Meretrix subimpressa, Pro- 2 iS) tocardia lenis, Pecten dalli, Ostrea sellaeformis, Glycymeris Eocene. 5 1 = idoneus and Leda cultelliformis (Zone 16).............---- 20 3 S Greensand with Tornatellaea bella, Cylichna venusta, Ringicula 7, S y J s J dalli, Venericardia potapacoensis and other forms (Zone 15) 6 2) — ene Totals na..4 ok: 2s sn MRR Ae eee s Mico cn oes 62 MARYLAND GEOLOGICAL SURVEY 71 X. Section of bluff one mile below Popes Creek. Feet. Inches. Neocene, Diatomaceous earth...... MAPK ee Ti ol PR moe 40 Brown glauconitic clay much oxidized in places.... 2 Band of pinkish-brown clay nodules in glauconitic CUR arate icicle a atath gid aise ohn pcacdmaaialtie tee ide eile arm ee 0 6 Dark glauconitic clay with many fossil casts .....: 4 : Concretions with occasional fossils.............. 0 6 bm nd Argillaceous greensand with many casts and occa- 23 SIONS ANGUB Se vers sak EC Loan Sea wae tes pL 3 Eocene. > 2 4 Concretions with many large specimens of Herco- aye glossa tuomeyi .........0250> OAC. die! a Siar. elacaixiae pe 0 6 AE Argillaceous greensand with abundant fossils in- cluding Meretrix subimpressa, Venericardia potapa- coensis, Hercoglossa tuomeyi, Turritella potomacensis, Mesalia obruta, Protocardia lenis, Modiolus alabam- ensis, Corbula subengonata, Mitra potomacensis, and (ge AS VRO Dee LONI S) (AOMWOEL) n ccaisieta oleeia miele ete 6 POUR ert aye wie a ao ny cis sree seatuinta a ernie cis a etaeec wre ea eae 56 6 Other Sections. Along none of the other drainage lines is the sequence of Eocene strata as complete as in the Potomac river area. Several important local sections, composed of one or more members of the series, have been observed at many different points and may be correlated with one or the other of the divisions previously referred to. Some of the more important and typical sections follow. . Section in ravine three-quarters of a mile east of Oxen, Prince George's County. Feet. Inches. ( Yellow glauconitic sand....................-..... 5 S | IWAGhine Ne Ge SA nee A So ee oaUcestes Soe ge cureocos : = ke Blackgsbellimiar srr. saiematchevel= etetts ater (ol ofeleiel)-ielaieletol 4 Wacene = 2 : Indurated ledge with Ostrea compressirostra........- 6 > oS Shell marl, lower part packed with soft shells in- = 2 eluding Cucullaea gigantea, Ostrea compressirostra, + | Meretrix ovata var. pyga Dosiniopsis lenticularis, | Crassatellites alaeformis, Turritella humerosa ...... 10 IH Bash Somos poe ren Oeo so soon ess owas 19 10 Section in Railroad cut near Seat Pleasant, Prince George's County. Feet Pleistocene. (Enos CGO i Gee ieee aaeig ooh at SO om else cae eb Orbe 2 aa bi : ; . = | Glauconitic shell marl with Ostrea compressirostra.........- 5 a z | Indurated ledge with Ostrea compressirostra, Modiolus alabam- Eocene. oe 1} ensis, Crassatellites alaeformis, Corbula sp., etc.....---.-. 8 f Feet. Z } Glauconitic clay.....-.-....-++++2++--+-- Be ee ree ef es 2 | Pink clay, without glauconite or fossils............-.---. 22 Stk Z ( Coarse glauconibic sand. 0-222 5- ie per age eee eee ee Shell marl with Gibbula glandula, Fissurides marlboroensis, eae Lucina aquians, Diplodonta marlboroensis, Venericardia plan- icosta var. regia, Pteria limula, Cuevllaca, gigantes, Leda | parilis, Nucla ovida 2s. 3% 22 ¢o cance fie ae ee | Indurated ledge with Turritella mortoni, T. humerosa, Mesalia ~ J = é a Eocene. =e obruta, Calyptraphorus jacksoni, Panopea elongata, Meretriz 224 wate var. pyga Dosiniopsis lenticularis, Venericardia plani- ae costa var. regia, Crassatellites alacformis, Astarte maryland- =e ica, Glycymeris idoneus, Cucullaea gigantea, Leda parilis, | Nucula ula ......- ct oe Sas non eetnints Sean eaten eer ae Glauconitic sand full of fine fragments of shells accompanied by bryozoa, echinoid spines aud foraminifera; and with Ostrea compressirostra, Gryphacostrea vomer, and Platidia | morylandica. (Known as Bryozoan sand)..........----.-. 9 TOLL: sieiek oc ones oo ore eee ere pene oe eee eee Beha Section in ravine one mile south of Thrift, Prince Georges County. Feet. Inches. Neocene. Lead-colored clay with Miocene fossils............ 40 f Dark argillaceous greensand....... Sener a et Mera orn, Argillaceous greensand,packed with Venericardia po- COPACOCHEIS’ be von oc oe PRS oper er oO eerste oreeapeen mee Dark glanconiti¢c clay = hee. coe ier eisie ee ees Layer of Venericardia potapacoensis........++0+200. 8 | Greensand with many scattered specimens of Vener- : icavdin, POLApAcOensis..... ee AAP eine oI Pee A 5 ¢ | Line of concretions ........ EES SE S.C owe. , 6 E = = , Glauconitic clay with Venericardia potapacoensis..... 4 ocene. o z 7a 2 ) Darkipreensand.--.2-¢ .--0)- = scan se ie reals 5 = 2 | Layer packed with shells of Venericardia potapacoensis 1 6 “a ™~ | Argillaceous greensand..... bd béopoeeEe Pee | ‘hineso£ ‘concretions. 2-65, -2 ee oes Nope erst 6 | Argillaceous greensand..... SaaS eee Ve ot Ae 3 | Greensand with Venericardia potapacoensis...... ee | Darkiplanconitic clay. 22. 222-2 2--er eects. | Layer of shells of Venericardia potapacoensis........ 4 | Dark clay, with much glauconite..... Son acres: cee — otal ea: o> oaiatatale len Unt Dee le ate aoe APNE 74 6 Section on bank of Patuzent River one-quarter mile below mouth of Lyons Creek, Caluexr Ci mnt. YEE EE Feet. Inches. Pleistocene. Sand and gravel .......... A PAT eis tee 6 5 ( Diatomaceous clay.......... + BIae = he BEE a BOE KY Moacene = j; Siliceous indurated stratum with Miocene fossils ... 10 2 prea 2 1 Brown gritty clay, with abundant casts of Miocene ss | LOBSUB clei cie oi a ea) toro mille alot ee ete anaes EO st Nanjemoy fossils sic - 2 -sertsiens Bice no cee ee ee 10.5 Line of Goncretions............. BAIS Be ta NS 2 eae perce greensand, with abundant casts of Eocene. Nanje- moy, MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE Vii 3S. a” PP ee ae = oa est, Fig. 2.—INDURATED LAYER AT UPPER MARLBORO, OVERLYING BRYOZOAN SAND. VIEWS OF EOCENE SECTIONS. MARYLAND GEOLOGICAL SURVEY "3 Section on South River at mouth of Broad Creek, Anne Arundel County. - Feet, ba Ferruginous sandstone full of casts of Turritella mortoni, a | Venericardia planicosta var. regia, Crassatellites alaeformis, Eocene. spe Bid darted te eta tale Sie patietsiors este ete mek cicie hae eh e Fidel lata 10 BCait es igs? oo retewees ) 5 re )) | S| oR) (SRS is! el Sl | sel eels 2 S/S i414 3B) [Sin O]: a) el a 2/3 =|. Ele lOlols F be H/o Olei4e! .JelolSis] alo “|e S\-|Flolo| | fal |.) | 1S) [She] |alelaleicisleleisiel (SiS! iSiaial | |e HESS! fo] S| | El E.|ERISISIS/Sisicla's) /2is\isleicl ldtelale aleslele| (SP Sisis| 18) slalS/S|Sialk|- Salsas) || alle] selstoc - | RQ) 2 Ol,s|/a/El= lS ih oP lPlo O/a Blo SSI eed ol ed fam Oh S/O) O)E siete She) 2) SS S| Slsl ale! Pda eal 3 silos Cle) S lala lS |e lmel=|S) Slelelele Siegler lec Sis lelelelels S/S /21S/S1e S SS| Sel El Siel Sl el el elelo| SSS lFlele ceISlelselce ARs sGeeeceeeccaciescenberlseeeeeeade Olo| S| S| SAO SSS olsisic] H/Sl Sols oF alS AS S/O/SlFlelolSlalolSlo EAR SSeoeSScbeclaseeS cece aoaaseeeria REPTILIA. | TNRECACNAMPSA SP...2-cceeee cree eeeees salle " E Aelleails salt Thecachampsa sericodon ? Cope ...|.-|..|- |--|--|-+|-+|--|-- collsalle 3 Ales 4 valle 3 Thecachampsa contusor Cope....... Salaa|oollaalaaoc is : ° : alecaseel| elle : ; Thecachampsa marylandica Clark .|..|..|.-|.-|.-|--|-+|.-|.-|% - Pale ale ilealleallen Pile Gees losilen ts > THU OUGSWAS Bi Dnooccs bead Soue Sobabeon bd ballsalloolioeloalloolloolloailoalles 6 : Balallen , Trionyx virginiana Clark. .........|.-|..|.-|--|+-|e« j sallealiectaallc 3 wlohe PISCES. Myliobatis copeanus Clark..........|.-|+-|--/--|--|-> % Be h eat aielles Aetobatis arcuatus Agassiz........ aalloaloalacloalloolleailecioollacloalloallccilaciioaliac BS ae 5 3 F Synechodus clarkii kastman .......|..|..|.-|.-[..|.-|-+/ 4 tS i Bu x Odontaspis elegans (Agassiz) .......| «|. Bh 3 : : 3 Odontaspis macrota (Agassiz) ......| |. a : : : Odontaspis cuspidata (Agassiz) 2 |lon|locle oll olfoalia oltealle F : : Otodus obliquus Agassiz ............ salslgolealoallss 2 A lbs : a lelevehoes aelees 5 Carcharodon auriculatus (Bln.) . alenealloalloriseldcllaa|sellosiaalea|Sollsclsallecioal solloolaclealdolsolonicalealdeliealoalediicalaciaalicaloolle cilooloals = Gale peeked latidens Agassle” se adeddc||b6lodlloaloblloallooljoctaalleallac|oaioallocliaalloallaciloall collooljac|foclleclloollonllociisolloctiaaieciiocilos|iociles|losiouilcollos ax s+ Sphyrna prisca Agassiz.. stehaveke 5 joe iphias ? radiata (Clark) . j ARTHROPODA. onennan Bythocypris subaequata Ulrich . Alsalleollrollociealioclosiloa| ealinellaaller Paleallae allocllea le 9 Saleeleeleeeate Bylhocypris parilis Ulrich.......... Ea liseetl artes ctetltovs | evel ayes ened tenet bal etel| ace sllaal| 5 |l0 3 2 seal sele Cytherella marlboroensis Ulrich.. F dallolioc “locale cS Ralisalsalesilc Cytherella submarginata Ulrich.. sliaallaolloalloalaclacllaallosiaalloollaalloolloaiisalloolloall oolloalloalle selesleclee| se ]-e]ee]==]-« Fibrolonile aliases Oythere marylandica Ulrich........ Scloalealloalbollealeclealoclsoloulasiodls. sels Selle "|- leeero leas Cythereis bassleri Ulrich...,........ Aol elcollaolscisolsolle : Sallodigal aalte3|lo aals Cytheridea perarcwata Ulvich.. S\lo0 Eallo pallonlloe)la MOLLUSCA. Ghtalcnenan ye Hercoglossa tuomeyi C. & M....... lee ‘ 5 seeieelen) MOLLUSCA. per ued Tornatellaea bella Conrad . apaoteslleciaa|solaallos Ae ealloe eallecilo dllecllaa aldolles Ringicula dali Clark ...... Ese e er ened eee Da Suet A ese co et] BPs esta sve ce fever aed ere ee enka eae Polen 5 . le Cylichna venusta Clark 2... .ccca.cc|ecleclecleclec|e«|-|!c||ool|o0lfoolfonl\ooljao|joe|| onllanliaollr mallets ast ; Alaiiac Mitra pomonkensis C. & M.......... Sal(sallsellaallealeolloottac : alts ve | ok alte BG Sloe Mitra potomacensis C. & M......... mo oaloolgalladie.cilad : j e alias aioe Latirus marylandicus C. & M....... alonlino| ollae Gallen oallacidcted|lociec Inaladitanl bollaclinells aah alee a Siibatlae Fusus? sublenwis Heilprin.......... Gelzoldaltoollanirollon|laolla ciel sllaciisalactooltalloalleallaalte ol he siloalls Fusus? interstriatus Heilprin......|..|..|..)..}.+|.+|a|-:|-. alootl ello oalloc te 5 “|: Trophon sublevis Harris ............ actloollaniloe “allo os or c ‘| Strepsidura subsealarina eT loollo % | 3 # |: : oy Melonyena? potomacensis C. & M.. jee vals 56 5 . | | ; if SPECIES. REPTILIA. Thecachampsa sp... +++. Thecachampsa sericodon ? Thecachampsa contusor Cope Thecachampsa marylandica Clark. ne es eal te s Buclastes ? sp Zones 11-13. Potomac Creek. Cope... ie MARYI sAND LOCAL GEOLOGICAL SURVEY DISTRIBUTION, NANJEMOY FORMATION, POTAPACO STAG KH. ‘hapel Point. _| Half mile below ¢ | East of Port Tobacco. | West of Port Tobacco. Nanjemoy Creek. 24% miles above Popes Creek. Zone 15. Ravine north of Thrift. | One mile S. E. of Piscataway. | Woodstock. | Charles Branch, between Rosaryville | | W. of town). ogues Marlboro (deep cut on new ee) and Upper Marlboro. | Upper Marlboro (8. Trionyx virginiana Clark cece eat] fed Ue Fad fd fs fae Ro ca PISCES. Myliobalis copeanus Clark.......... Beate Aetohatis areuatus Agassiz.... Synechodus clarkti Eastman Odontaspis elegans (Agassiz) Odontaspis macrota (A gassiz) Odontaspis cuspidata (Agassiz) Otodus obliquus Agassiz Carcharodon auriculatus (Bln) Galeocerdo lalidens Agassiz eeyria prisca Agassiz.... iph ias ? radiata (Clark) ...... isedsal (scl eed foc Mel eS Pe ARTHROPODA. Ostracoda. Bylhocypris subaequata Ulrich... Bythocypris parilis Ulrich Cytherella marlboroensis Ulrich ...)..)... Cytherella submarginata Ulrich....)..)....)..) OCythere marylandica Ulrich Cythereis bassleri Ulrich Cylheridea perarcuata Ulrich Mouuusca. Cephalopoda. Hercoglossa tuomeyi C. & M........ Mowuusca. Gastropoda. Mitra potomacensis C. & M. Pleurotoma potomacensis C. & M...).. SF fy (pe Loan Plewrotoma ducateli C. & M........ Sc|oal Bol Bel Ballacl Bel eal be itra pomonkensis C. & Mesaecuats Serfaty Real alana \Latirus marylandicus C. & Manne tn eat ee | PS Pusus ? subtenwis Heilprin .........|-.).-)--|--|e-)ee/e6) e+) Pusus ? interstriatus Heilprin...... wefee[eclec|eelecfee| sles | Hills Bridge. WOODSTOCK STAGE, | + | = | Pe i | es y = | |Z : z = i- - — _— « = 7 = “4 a aa = ™ 2 = = = ~ ~ lol | = N ei Popes Creek. Deep well at Chess ck. Two miles above Popes Creek. 14% miles above Popes Creek. | La Plata. Woods ca oe oe ae * ca feet). Piscataway sta GENERAL MAKYLAND PROVINOE, Potapaco stage. re. | Paspotansa stage. Woodstock stare, | Cretaceous. DISTRIBUTION, GULP Lower Chickasawan, | Midwayan. Upper Chickasawan. PROVINCE, Upper Claibornian. | Lower Claibornian. Jacksonian, ao = * 9 , ot — Post- Eocene, 1Harris: Bull. Amer. Pal., No. 4. 3 Harris ® Harris: Proc. Acad. N. Sci., Phila., 1895, : Bull. Amer. Pal., No. 11. 4 Aldrich : Coastal Plain, Alabama. ~2 o> THE EOCENE DEPOSITS OF MARYLAND LOCAL DISTRIBUTION. AQUIA FORMATION. SL POPE CRT RR IP A RN TP |e ale PISCATAWAY STAGE. PASPOTANSA STAGE. 5 G $| | |s < ele al | |e i) fe F e |g 18 | |olo : o : q ie > Als Ia | |e PIE) pal iS AIS alesis SPECIES. Sha |e a) Els eS] 5 Jo sig! felsle 12) = n 2/8 3 ole! |e S| (S/Si (Shslal lal le ola) |Sicis S|) |o S| Bla) Sisizi |e! Is Ks SH Ola) |z S) fas] tela ja] js AIS!) lalols Ble| |x a! SA (Sats) iS iS! bd] | (Sil msl FS) Slug S| JORt] jojat St] lal sts air ales ap QIS/OS/8 . = ballike) Che Sige! lelalels tH 210 ais! S858} | iS |.t | 18) Shel laiS/Sis/epaléisisig) [ele] relgia) | jas belSBIR | sto] lel | (2) RE) [ERIS RStoSIaIS| fas) /Z/E/2| |alele Blaise] Melee (Sice|SleiSlelelccsclalsle| |S) e\SlelSlale ale la/2) JOlals/ Ola SIZE SE IA pO] alae] 5) FAIS alS ol al alala QS SFC SISO EIS) Sl Slofs aloloP |S o/olPslols|Blolal/SlShaisisieiala Fe al aSlSCISM (CIS) Flies | 4/2 celals els r=/S|S(= al o|a ais (e/S ale Sia ls |qlE S/S SIS\S la] S18 =/S/5/9 BlEISiE EES iaiziS|A)e/5/Raclela el ole) s|5 Slalslols|a | 5] a) ° 2 Ble 2\2|/8 =e. |Si=/s/8\aia giz iS|s/Sie|B gis] /Z)ealaisioisiSisielale lola Fe fa | fn I fm fh fe I I OIE IIS IIS SIs IO a8 1 I a a | fo (0 Mouuusca. Gastropoda.—Cont. UC earn ane, (CE Oe Wiepsocos Salida lecllassllooloallaclicalloalloalloc|lacileallac|ealloollocllccileciiaa|aallos|leaiicallfallaciacloalaaiiealicalleslloalhs olla oils 0 ; 4RNGOIGh Bio 5960 0000000 00000000 0000 osolcalloolloolloclloollon|tcalio Ralls alse Balbo #3|loe e Tudicla ? sp..-.-. Sapacladicaloalooloslociealaclosrslsctocloslsslloolloaliaaiocigollosiaaloaicalsolsollos|laciocllaalloolle sllos : Also Levifusus trabeatus ? Conrad....... Ballballodleaiisollselactas!lonisellaniica sali Solloalonlls rile ele a Be Blak Levifusus trabeatus ? var. ad: Sled hl esl cal al selon celiaoloalonlsollaslocioslwaleatanioullaipatselles allbollaollactleaitc . Metula marylandica C. & M........ 54) |5lloal[sellon|collaailac|Gallocliociiac| igallscllacllac|[solloollaallccllooll =alleall eslloc allbe B Voalasiino Chrysodomus engonatus (Heilprin.. colos eallealloo ae ; Be IEEXAVVOKMNG, SDs0000 0009000008000 00500 Sollociicallcollonlicclloa salloolloallaclos caffe alloalioo|| sa] x: aiwolloul|oc Tritonium showalteri (Conrad) ..... palfoallan paleo selitealless Bh . r Pyrula penita var. Conrad ......... Snilealablealoslacicciiaalloaioaloais salloc palaciow , Pallgalloolt IP PUVIGL BD SOs as00 06a 0000 4080608 Sinncé sllosloclbolloailoalloolloclsclealloo|oalloalloallontioolle 5 Hele. Belgolocioc Fulguroficus argutus Clarks.', 4s 85 oe sollealoalesioalsallaciiaslealeelns 4 : “allool| ea | = * : dBollou|sellac||a Fusoficula juvenis (Whitfield).. Blige Halk soll ea Ale 2 i : Morio brevidentata (Aldrich)....... zlfeell eyelllere Gals lloolley : ae 3 Cypraea smithi Aldrich.............|..|.-|.. 0 aAlpelwalte : ih j Calyptraphorus jacksoni Clark .....|..|..|..|.-|--|--|--|--/../.-|.-].-[..]--|--]- alles fees “ Pallgelicollsic Calyptraphorus trinodiferus Con...}..|.-|.+|-.|.+ c ballesll silo Sc amisel alas Calyptraphorus lLrinodiferus 2? VAr..)..|++\eelecleeleclecleelecfeclee|s 5 é Sa |loalloo ie satese Aporrhais potomacensis C. & M..... oullecioolballacilosiloalleallacilolio 0 * oolealle on oalle 5 Turritella mortoni Conrad..........}]--|%|--|--|% |x| |e] s elie lloollesileslloc = allo a Turritella humerosa Conrad....... x P “alles loolles loolloall ea lool : Ee F Turritella polomacensis C. & M....|..\e-jeejesjeclecleejee|e . aalleelhie is : ae siete Mesalia obruta (Conrad) ............ Selael aloo ealigalaclon Selects Pelee . f eae Vermetus Sp. -5.. .--..-+.s00- sovoocolan|en|co| ga|loollo : alee * Bile Natica cliftonensis Clark ........ Sou colooleoloalsclostscloaloelealicellocloalss aolloalaal dels allealioollc Bal eollse ad Lunatia marylandica Conrad ...... 2 |[Solloo|laclloallea lies allsallee|loalloslles thes ley llooll ea lle i lea Sele Calyptraea aperta (Solander) ......|s|.-|-.)--|.+|% i ealleall ea & : ils? Litiopa marylandica C. & M........ sollocjoalloollooll aol solloalles oe aleralealiete SGLa NESE Ouse accent solloa|ocléc|eolloollealloallociloolsolleolloolfoo|os : gilleollac 00 : E Scala virginiana Clark ..... Shdooaa|/aoloollaolloollbelloallfallaolla olla ‘ sles lloclloaloalios : aalo0 Scala potomacensis C. & M.........- sollec|oollosilealocloollociodiicalloolf : oolles a0 : : : Scala sessilis Conrad ................Jee|--|e-|es|ee|eefeales 5 : salleslacoclos 3 cal[enil alto Scala carinata Lea .............. : oullss|foofoo||se lias eofloc Turbonilla potomacensis C. &§ Wikeaoollos|oclociaoloalccllaalle clots : la lloollaaiton pallaclselle Tuba marylandica C. & M..........J..Je-|..[.-]..]e> A ealloollool| es alte 6 tate Odostomia trapaquara (Harris) Bavdliacioollon sleells =a\lealloollasifealiaallc a Je Niso umbilicata (ea) .............. salloalfsollos : . glo 20 Gibbula glandula (Conrad).......... ool fo Silas & s i COUMOSTOMG SPP.....- 0.0 eee ees wen ceee rs ; soll ss lie als Fissuridea martboroensis C. & M. : |e =i eil i : Mouwusca. Scaphopoda. IDA OAV OOH EOS EP LOK EU HDD (Gr2)0) ago) |aq) |Galloollad|iaollan|oallaollocliselloniiod|ballocieclianiioallaalianisalladiaalonllaniallas|locllecllacicallaatloslloallaallaciiociion |; Dentalium mississippiensis Con..... veil evel stone] Poteet ste ; . calls alealle: . i ollaciow Cadulus abrwptus Meyer & Aldrich.}..|..|..|.-|..|.+) allele talitclavale ; Mouuusca. Pelecypoda. Teredo virginiana Clark ...... Esedodllod Halle % x ¥ 4 ¥ ‘ walt Phenacomya petrosa (Conrad)... flea : dollsallac re Salleallo Gaslrochaend sp. ..--- 5.0000 9000 ||solfo0 06 So llscllanls x Bollodfens Panopea elongata Conradias. een we lak fee [ oe |e 50 [calloollrallelleallesteslleniieacollea|ies ; % Corbula subengonata Dall.......... callcoloolecls ne ateva (eke ee loalles . Corbula aldrichi Meyer...........-. solkialldalloolle allo Salllereiliste ; Corbula oniscews Conrad... ...e.sceeeleelae fe Be p Solen lisbonensis? Aldrich .......... salen ail 50 are Tellina virginiana Clark .......+5+ SH \aollooleolloalocllealloolloalle Bo ‘ alle 90 Tellina williamsi Clark ........6+ doll aallon : 50 c Telling papyria ? Conrad....... Socal alloolballadtlocliadiicalloaliaallacilooliooliecioolbalballoalle 6 Meretrix lenis (Comrad)........ ....- sell salle ; BalRalee SPECIES. Mo.uuusca. Gastropoda.—Cont. Tudicia marylandica C. & Tudicla sp.Conrad ........ Tudicla? sp...-- Levifusus trabeatus 3 Levifusus trabeatus var.? Conrad. .. Chrysodomus engonatus (Heilprin elke Pseudoliva sp. ; 10 2 Sy 36660606 goto pedo opsosnad Ise Morio brevidentata (Aldrich ) raca smithi Aldrich............. Calyptraphorus trinodiferus Con... Calyptraphorus trinodiferus var ?.. Turritella potomacensis C. & M.. Mesalia obruta (Conrad) Calyptraea aperta (Solander) Scala virginiana Clark Seala potomacensis C. & M. Seala carinata Lea....... Turbonilla potomacensis Tuba marylandica C. & M...... _ Niso umbilicata (Lea).. Calliosioma sp.....- Mouuiusca. Scaphopoda. _ Mo.uuusca. Pelecypoda. Wemeredo virginiana Clark............|.. BESET OCNAENG SP. ........ 00.2 cece ees Panopea elongata Conrad Corbula subengonata Dall .......... Corbula aldrichi Meyer Corbula oniscus Conrad Zones 11-13. Potomac Creek. Calyptraphorus jacksont Clark..... Fe els Da La a |e i MeL SESSILIS CONTA .......02.0.0c02|--]-*|-| Phenacomya petrosa (Conrad) ...... ..\..|.-\-...)- MARYLAND GEOLOGICAL SURVEY LOCAL DISTRIBUTION, ~2 ~ GENERAL DISTRIBUTION, NANJEMOY FORMATION POTAPACO STAGE. | ] be} s Branch. between Rosary ville of Piscataway. - = o ys | 5 z= s - - Fae 5 ~ 5 oma las 2145 3/0 +12 y/o we | _ foun) i . ne 3} 215] | SSIS Sit) a Si 5/| &) 2) - ~~ ¢ O1S) Slohs ies ze ov esa | oO} e|\VlAlS6 A905 yc NWSIsOlL |S Saal S|— wie = aH =| & Di sno. = 5 010 DISlolZia|© a sills 4|,2 <] fas DIF Ool2IN|_-12 S\isio | S E 2 ie om | =—- = ike, . =| | (Pe 15) = . 2 | Olele)2)5).) lelakisia |29 fol La — we, > — > lel 2 im bIClolalsla|\Zlelkaiaia ia loll lential ~ . e) Als) alo| ld QSsis a) 3 Bilal S1Ole| 1 5} a ale = 3 . 2) Piers 3) °}o| Blasi 3| a)S) S| elas 5) 1-42 | Sale| Sl Sls alolos|7i— SlalPIHIBlol a(S alala Oa, Blalois TS! Clela Se aS aesic Bol sl SlelS| dials sii AS) a A l(a] jan NS | A lait a i 4 Lam! fame m\= |O|S|O ~— | } | “Zones 16 and 17. Two miles above Popes Creek. 14s miles above Popes Creek. Woodstock. Popes Creek. 9 WOODSTOCK | MARYLAND s STAGE. PRoOvincE.| | GULF 92 feet). Deep well at Chesapeake Beach (90- Piscataway stage. Upper Chickasawan. = a = oS L = on] | «+ TREO ERES Tio oisio, ss sistas voici sie iciereis erwin Se (lt Fg Mveatied cliftionensis Clark ....-...-..|+-|--|->|.-|-s]>sj+-| o-|+« Lunatia marylandica Conrad...... --.- Watiopa marylandica C. & M........|=-|--|+-|.-|.- 7) S| DMRITUNINSIs Js ce sass cs cece hanes ial lea al eel sel el Ger el fee se Odostomia trapaquara (Harris)..... £1 0 fe [ Mila cloniuta HE sede cos! ot odllocllodlodles|an!|sd oe Fissuridea marlboroensis C.& Mens i a bre a Tapa vl a Dentalium minutistrialum Gabb... ..)... Dentulium mississippiensis Con..... .... Cadulus abruptus Meyer & Aldrich ..| C . couecdo jar ‘os ki xls | @. & M...-|--}- b | | } | | } | = So jiod| |e) | 2 Spe ilee| eis * LD 1 Harris: Bull. Amer. Pal., No. 4. 4 Aldrich: Coastal Plain, Alabama. 2 Harris: Bull. Amer. Pal., No. 9. ~ wR RRS % oe -s m * sz *% % . oe = A 4 NE on *& ry 5 9 9 9 1] 3] .3 3 ‘ 2 2 o* = % = * we % % * = ? 9 x wz lee & i “* i Eales ul} 13) 23) 24 é Sav PSY pee eae t 2 4 5 7 - ‘ 5 ? ~3| ~3| 4 3| 731 ~4 % es) se] = % % mad Wes < 9 . & on ool = % ee] ee ee] mz oof -- 3 : 5 A oe OF 4 “- = a= * * = oe. -—* ee 3 tees 7 ia 3 Harris: Bull. Amer. Pal., No. 11. pper Claibornian, Y } toa PROVINCE Jacksonian, Post-Bocene. > Harris: Proc. Acad. N. Sci., Phila., 1895. 7 Dall: Trans. Wag. Free Inst., vol. iii, pt. v. 78 THE EOCENE DEPOSITS OF MARYLAND LOCAL DISTRIBUTION. AQUIA FORMATION. PISCATAWAY STAGE. PASPOTANSA STAGE. = Z ~ . ie) | se Neale [Ps =| ee Bl |. 2} |) 18 4) 28 alg| |z el E Bia| fel (8 8] elgis SPECIES. Ball | g| ela] | lel) BI fe ec] isle olsl |e 8] iis) Sigil lel ia Ole] [Blais Blo] |S =I Si O14; 19] |e Si-| |Slola Oln D on =|a DQ) \45 i‘ Als 21 Py Sle) IA S| SM) | Siaval isl (Sl isl | isi2| eee of | cS |e Sika) G2) i/o TS! lolslo g|S/org]e 3 +] flo SSE) ala rlslols |= glol8 ‘ olla 3 re) Ole, -|O S16]: HO Ole | op Slelozls] | el lal | lS] baie! |EaiSicSiSisClsl lea! (Sisal | ls Se ISIS ey irs AF) JERS slsoOlgis| (2lo] Jola=| lake Slalsimi| loMlgisi| |Sicis/Zia| Sie «| | og | SI Bla /ajole) |2is S)a 2) 6/0] (Dials Ola] (SSeS LIS Apo Olm|a/el2| FMS o Ol ale le Q/S/3/E/23 5S Si18 [eS ialzla| Sle Selo S/F SS Plole (si Cisia eas 2)5'| 2/8 |O a, dinlia ap = Ooi) Sra re| Saisie Dis |O) Bre Slelm Alas |S ae SSS olalsiolS| S/S/S/Si/g Si slolaleiol sos A al-|SiSia 8) a) Sha) sic SI) O}=|F)0/2 g | Old] Fi pIS| sia P//2 E O/F 12 || 19 3 cs) Olo|a Ele »!S\o/e B/S] 212) 5 =| Se |S SS CSS /SSe SSeS SSE sis lala Sislelclellelete [fe] a JO 4 J J FF HY SY IY J ea | fs I |e | 20 | | Mo.uwuusca. Pelecypoda.—Continued. Meretrix ovata var. ovata (Rogers) ......)..|..).+/..|.- Meretrix ovata var. pyga Conrad ........ ea|\Ballesllon| lool eal calle Meretrix subimpressa Conrad . .........-jee|eejee|ee|eelee|-e|ee Dosiniopsis lenticularis (Rogers) ......... eallcalles|lacheoll es Protocardia lenis Conrad........... ve cere mele efatste c= «fale |= =e] mle ele |-lailee|« = Diplodonta mariboroensis C. & M.......-.|--J--|->|e-|--|--}o-|e-|ee|erlee|>-|e-]e-|-o[e-|> Lucina aquiana Clark ............. zope oo ecllociicclloo|sdllos|ieslliolealle dealloollocl|sel(polleolloc Lucina astartiformis Aldrich............ doltyallellea|ooltia| aalltallodiloailon|ixallon|oelballoulip Lucina dartoni Clark........ oe dereaeroeee pallgolle. \ieal Holic Ewcinia, When Clank, ...ncd sees se wore zvelllgee | speil lene’ [evel ae WWeing WNiben, Clack Sere criss
  • |--|.< Venericardia marylandica C. & M. ...... Sal Pela rol eral lerelallaolo.cliaal les Venericardia potapacoensis C. & M..... alsteletloelerl lee Crassatellites alaeformis (Conrad) ........)%\++)% e+ le- | | Crassatellites aquiana (Clark) ............ Sal allel sel eal elle Crassatellites alta (Conrad) .. ............ Pel alealeatCallealleelted| oleic Crassatellites 8) 2.2.21... eeeeee iaisa bieege eas False as alata ieee loolietel he “ Astarte marylandica Clark ........ ..... cal Belk eel nella eeliec elloallaal eallaulvallwalloalhoolloclisuilae 3 Coralliophaga bryani Clark ............. slcollecl eal eal eolleailau||oo|lon|ion) ool lal |aallsoljoo|loo|eollcallcallealleallesllouliouliac F Periploma 2?) sp...=..-.-.-.---- SOOoddee 5o|fad| aol sollgollan||acl]olloclloclioalloollsalloulooliealdal|colloaliaciicalicallaniloctinallcallociioctioallosiloclloslloalaclioolle: al Pholadomya marylandica Con.. fees Alboloals|loalleaile e Modiolus alabamensis Ald. ..... .. -...)%|--|--|--|--|e || %|--|e |x [e-|e-|ee|--|e-[ee| --[ee|eo[ee “ J6 Modiolus marylandicus C. & M...... BR Cee (Ge) (Se leat aie ec eliae! lela Bol ida Se iolsol|od Bala Nepligal bal lsnligellaalideliddlloc|lcallcollaclaellocliociiacioe loc] acl: - Lithophaga marylandica C. & M.......... Bel (oe 0 bd eral eal tare let ictal trai tere el oat illest elloel lal erellaciioalbellsclloc : FE NOOR ULON FU eH OG KOON Cpitcsiis Goo caddecoosleolselloa|eollon\sallac|aolleolieslloalloallac|salleciiaclsoliodlicallselleciloclsollaciloaloolioalacliselleclioella Pecten choctavensis Aldrich............. Fae (es fect fee ened lezet ese ise lene eves eel Iv fc [Sasi Pence Ieygiiy Chath, OMEWAR cheb cedé bopeseoes sacs Aa al ashes thee late ell latell cal etait are | etl ove | eee Pecten johnsoni Clark................ Beebe aollaallenl inal elias eoleslivalloa| salen IZWOUWHD GOS asoasquosocusoacsoncs See eae Ralksolaa acl edited tc Ostrea compressirostra Sayzercmencraee Palle : Ostrea compressirostra var.alepidota Dail sdllociisollsalleales|iooiloc dollodllbolloliocl| acl'6aljoullscllocllociiac ce Ostrea sellaeformis Conrad ............... Bo) Bal Bolleal eal el alone) Sol lal alka bolle eel dcltoal ool balsetiGolloclicdldallealicctsallaclioaltocllaclioolioe Ostrea (Gryphaeostrea) ) vomer ‘(Morton).. efeelee| ae lee | ae |x Gryphaea vesicularis Lamarck...... Be elas laut eal ee) lac | aol onli elie nellaol ballon! Salling ollad|aellec|icalloollealisells Pteria lVimula (Conrad)............. Bees ee yal hia| a eal eral eed olla ele ial ral eal Ae eral a lea aloe) easlldolbeottss|igolioal Glycymeris idoneus (Conrad)....... Gueodalldollse oclepltocleclinc|daltaecollsellsallsalbcliecioclloc (oa IK UNKooNn ee) (Ke eH ((Clora\)) DON aaoe cana-ollociealloaiaollosioellocleollasiienlloclioalsalluolloclioclocl Cucullaea gigantea Conrad ............... Ja |ecleeleeleel ae #lee|a leelee Leda parva (Rogers) ... ............- sogoolonoclivalcaliaolloclioclica|ies|leailoclioc Leda cultelliformis (Rogers) sueetsictnvere 6085-\\locloal!s Leda improcera (Conrad) .......... svete loleherel| tell tell eke Leda paris (Conrad) ee. -eee eee eee alnalaciesl ales eraliorsi| ellen melt erate aa WCAC PONS UAT ee eneeeeeeneee tern een Belloc loc! Ipal eal era) lecietclas an late) esa eral iol eel lea ol feral eral alia foal aetiocliedlian| a! acllacliod|walioollecilectloayoc Leda potomacensis OC. & M. .........0..-. srel[ferel tell etal Pevall 'oPs Leda cliftonensis C. & M............ Senn Salloa| al Heda, tysoniC: & Mi nae sc ccs ceraee S6b0\coleal acl ool Golleq|laulaciioc|sel saljoc|iocllooiiballeo|toal| calleoltalleallec INACULO OUUTG ECB. econ sleseele «ces ene Jae[eelesleefeefee|esfeelealeclecfeejec[ecleslesler|ealecleclacleeleeleelecle| Nucula potomacensis C. & M.............. MOLLUSCOIDEA. Brachiopoda. | Terebratula harlani Morton.............. Galloal Hol leal\callaa|ioaldollor Platidia marylandica C. & M............- aoleelts MOLLUSCOIDEA. Bryozoa. Discosparsa varians Ulvich..... ...-.....|.. Inalloallaciiee)|icaliaa|laalleeliogllee Fascipora subramosa Ulrich.............. Stloal oe Reticulipora dichotoma G. & H..........- ed all ee aellatalleteldeeell crate cal cre volaalerat 2 Cavaria dumora UWirich..........:........ Fb 6 EG 6G) (or eto lel I ioe ibiol argc bol aol bat RalbnelMe bey bry Belen eile! iui heal ldallncl nel lacleetsniictal lo aloctor LOCAL DISTRIBUTION. MARYLAND GEOLOGICAL SURVEY GENERAL DISTRIBUTION, -z © 5 Harris: Proc. Acad. N. Sci. -, Phila., 1895. § Dall: Trans. Wag. Free Inst., vol. ili, pt. iv. Rye ae FORMATION. POTAPACO ‘ WOODSTOCK | MARYLAND z ae | STAGE. | f STAGE. PROVINCE,| | GULF PROVINCE. | } 2 | le = | = o | ~ | | | Neate ie = ra f | | a . | > | Heel el =e b= -| | |3 | Ra Prato bel te: tele Jal.| |S | | ar Ms | 2 -~ - - 4 — SPECIES. 7 | | fale! (S| i isis lela} | | | | =| |) Fig) jal ie [sie Bele! bs vice. 4 a! | | oO) [sso | ste 3)2\0| | | | ©) Id] slalal «| ste & Siz|2 ko|Q)col 1S, Lp all 6| |SlolS/ Snes! Za5 Si" | aloo) | | Wea Wicd | SN] [3/26 | Slo/Ms|2oa\— I 1Si sla} q| MISIBITIGlalei I alslo glo! ja | ole 3 [El El |e BIOILTOlEla|C| Ole a s| ols lei Ie | 50) bol | bo 8) 3) a) SIDIFIEIOILIN| -|Clesl61o Niole} | S13) fla mio) ae olRlelstals| |Sisiawisie le elsict3 lalalalel . ES eile 4 AOS Rlolaly) plei\S oma lao |elPorsl_. [ml alo a| -|o|0/2/2| gla sees sseseaca | lsiseeeq| 2/4l913|s| ialsigialzis io = _—S [oot ~ a | | = oS a - al ter! om | C BE SslaiSelsleS>\a[-s4| see sclrs| sie 3/2) 8|2)alale)\ ose | | eo = m $| 2 = | g mm | am | a! Selsles BlS| SESS SM AISlolFIS eels lei als 2ie\2/s/2/2/2s 0/8) 2B Slals| slala eA Rasa] OES OS|2/a/5/ C0} 8)=| 6] 2) 6] ee) 21s GiZ\FBidiselomo PP MSE aa |Ala|aIElOlala|p|4a/b/5 (a Moutusca. Pelecypoda.—Continued. | abel Set eal Ae pal ee {a ad Meretrix ovata var. ovata (Rogers) ...... Vee || tle teal 1a | ey (tea eases tere Wee pe ime | Meretrix ovata var. pyga Conrad. : 33! |. «| col betel bel gel BAe Noe lice || gol ool EF S24] Meretrix subimpressa Conrad........... alia leel rol el el x |e -fale-|--] a “Ailes oth ad Ged PSS pel ee i Dosiniopsis lenticularis (Rogers)........ H0|| 00, 00\\50} Were |frcieil sve a] = (hey lKoall colt adlloallelhe Protocardia lenis Conrad ...........- so {heal eeldel belle 56] dolls! x BA eal laos fo geal | eal bia 3 Diplodonta marlboroensis C. & Mig ees, mele oliee las 50) Sail 3]; call eellion| dal ae Lucina aquiana Clark .... 2.00.00. sees eee pal belle .| Pa\liey| --| 2]? Lucina astarliformis ace airmedonagosd .| .| Beles bal eerd | Tucina dartoni Clark..............-.. daaaiteciigat | ui | a Sie 5 Lucina uhleri Clark ............ Soppeneear | ai Taicina whitei Clark ....................5. Ballon lee bing? Git 6600 adeaeoeoob00e500 5900 boodebn! | oAllod| ic Saha esl Venericardia planicosta var. pear (OLoF M6] Go! |oolloollaaita a eonl eau Venericardia marylandica C. & M....... ealloal oa | nea Venericardia potapacoensis C. & A soc! | <2 | : Crassatellites alaeformis |(Conrad)........)..-. Crassatellites aquiana (Clark)............ vallbestl : Crassatelliles alta (CONTAG)........+.ee eee) ve ee at | i BMMPPERLLELUALES! RP) Sinise cio ss se eeincce Canes sews ae Receath eee Aslarte marylandica Clark ............... Coralliophaga bryani Clark .............. | Periploma? sp. siliesliact 2 Pholadomya marylandica Con............ Soho eal al el Wel aes Petal ioe a | Modiolus alabamensis Ald ................ (ealeélloal alles = Modiolus marylandicus C. & M........... | «| 5 ie Lithophaga marylandica C. & M. |. allel Sail rai exe | 2 Anomia marylandica C. & M............. .| alles\eallealles| a3 Heep each a Pecten choctavensis Aldrich............. \eellsclic =| as =|--|+-| | =| Pal ero! ae | 2 | Bale RET OULG ClATKS ce). oclid sci oricciemece ee alle alte a eo] | Pl PO ee sel heel owt bal | 46]... Pecten johnsoni Clark..... Sood Alle ee alle >| holla cole? Ree ies LOD. BYDL eclsogdee DOSE ORB e Bee pe Ooo bbae Setonee Nee Ee Sel Bal ae Bel esl fe ee ee 5 bes eal (ose eed veil ete leaes| Ostrea compressirostra Say ............0.. Bel Bollec tel hal eal bol feel ae Eee es 22 A Nae loo hoe | be Ostrea compressirostra var. alepidota Dall)... |---| Beiter Sc #5 ||/0|) 00] | Sal) 28\| ee |e |e rea sellaeformis Conrad ...........+... : * we [ee] | x ealoaale trea (Gryphaeostrea) vomer (Morton) - li .- sujal cies | So |e yphaea vesicularis Lamarck ........... it Allie ail hee Woe eeu iectlers tema limula (Conrad)... 2... 02. 2. 2.22: | +-|e-|-]e= ‘ Rea ecsed ees Pe Glycymeris idoneus Coorad............... eeeoeooae | eM i aaa Trigonoarca decisa var. Con. ...... eeeeeea| teireleeee] | ll teil 2 i Cucullaea gigantea Conrad........ SHO OA I) eo le : lhe | = 5 Leda parva (Rogers)... ...--..--... sees eee eee | re =| Fs (een sed (eo ; Leda cultelliformis (Rogers).......... Sell Dll Jes] x s =3(\eeil all Meag improcerd {CONTAG) -.2..c.. ce. oes e| cf leeds fo fisdefee|es| o= dee oe | Joe | x | x Leda parilis Conrad..... ones allavateaventere peal 4 Nes ese lacs Heel MEAG PATS VOT. oss. cece cece cccccevesssese|ee|es| 30 “ ; ees Wiese ee Leda potomacensis C. & ai ee ache relent leate | x P P we|e-] a | «| \68 {| aalloc Leda cliftonensis C. & M. Do : | se Lies liso |poall c Nese MESON Oo.85 Me ooo. ce. ccscessusieesees | ee ie «| 20 |'0l| ¢|| el} bell a/| cal] ay) wa lpoo| ° MUL ORONLUC) WOR taicaecc cr seee eos sce eeunalie: -| esos Gla) keel al se Hise Sed et fee ea | oar Une Wucula potomacensis C. & M........... : x = Pa bo fool lx | 2elPeat al eSl hoa heat Wea ¢ MoxuuscorpEa. Brachiopoda. | | Eke | | | | Terebratula harlani Morton ............. SB Baba bel bel bal ee foal eel 1. | ua pa [ee tras ese : Piatidia marylandica C. & M.............|--|--|--|--|--[-+[--| --le- |--| .| | POA hho ee MOLLUSCOIDEA. BEYO: 0z0a. | Discosparsa varians Ulrich.. = |Wical|f oad |e Fascipora subramosa Ulrich . 3 | zi iculipora dichotoma G. & H. | = # @ria dwmosa Ulrich.......... ......: se Nees Posies + Harris: Bull. Amer. Pal., No. 4. 2 Harris: Bull. Amer. Pal., No. 9. + Aldrich: Coastal To Alabama. 80 THE EOCENE DEPOSITS OF MARYLAND LOCAL DISTRIBUTION. AQUIA FORMATION. PISCATAWAY STAGE. PASPOTANSA STAGE. SPECIES. Brooks estate. near Seat Pleasant. Three miles W. ot Pisgah. Liverpool Point. Reedy Kun. Piscataway Creek. Potomac Oreek. Between Buena Vista and Collington. Crownsville. South River (mouth of Broad Creek). South River (Sheckels farm). Two miles below Potomac Creek. Annapolis. linkers Creek, near Piscataway. Paspotansa Creek. Pomonkey Neck. One mile 8. BE. of Mason Springs. Swan Creek, near Piscataway. One mile N. E. of Grimesville. One mile N. EB. of Piscataway. T’wo miles south of South River. Glymont. Three miles west of Leeland. Seat Pleasant (Railroad cut). Collington. Fredericktown, Cecil Co. Mattawoman Creek. Upper Marlboro. One mile west of Hardesty. Fort Washington. Hardesty. Aquia Creek. Clifton Beach. Wades Bay. Leeland. Winchester. Severn River. Rolphs Landing. MOLLUSCOIDEA. Bryozoa.—Continued. Ceriopora micropora Goldf........... dono |oolbolad| Gallen ecllealieo| ea|eallealealleallaciladileciion!foallaclocliacloellaaiacllocllocllacitaclleallacloolloailoc locllocl|=el loq|laql] cn foo} a |!.6r Membranipora rimulata Ulrich........ sn5||Eaioalsalioc|ioolad|sallina|ies|| cod lodl! 66 |[64}} colloe|pollsaliec Membranipora spiculosa Ulrich..........)++)-- Ieal|sallooloalioolfealisall! co:|bal Membranipora angusta Ulvich........... 66l G0! |00| (ou! oa! 60) 50) hoo foe Reptoflustrella heteropora G. & H........ sallscilea||eal (oles [0s| faalloc BBiustra torta G. & H...........8. eee eee 30)[o0)|ac velecleeles| cele oe fea] oe [ea] scllaclloc Eschara ? digitata Morton..... ......... vefeefeefeefecfeetes|eelee| oe [ee] oe fee] eefeetes[e]e- | Lunulites reversa Ulrich ................. seleclecfec[=cfee[eslecfeo] o- [oe] oo lee! }Cribrilina modesta Ulrich............. seve [eefeefes[esfeetec[es| oeles \Cribrilina crassula Ulvich ..............5. wofecfee{ecfer|e« cdlaallbs | |: | Lepralia subplana Ulrich ............ coef eclecteslecfeclecter| ealee “| | Lepratia labiosa Ulrich .... Diino aerate wafocfectecter{ec}ec|cctes oo lloc!} ao aboaleeta sales os Mucroneltla aspera Ulrich ............. wefecfeefecfeels Jeeferfeetec] ee fee] oe feel eeleateeteodee a | ; COELENTERATA. | lea UDO OS TE Ge cGee te aes Geers aaron Meee ds} |(oe|69)(00 5a] bel| eel bel ee |jeaslesee pall as) esl bel fe-lia8| ec Filion||ee|lcol)/sal! de |} Turbinolia acuticostata Vaughan........ | TK A a sa Ds Paes Kes Ps FE ee bares ical hee hat Ceol ea Trochocyathus clarkeanus Vaughan..... eilool|o} ed [eel Ie : : | Paracyathus marylandicus Vaughan....|..)..|..|..|..)..].-|..|..| .. |.- el rel te 2: ot 1 Balanophyllia desmophyllum M-E & H...|..|,.)..|..)..|..].-|..]..] .. |e. silica = 8 | Eupsammia elaborata (Conrad) .......... cab dose sea ee nal ellensoallee allo : t / | oy | PROTOZOA. | | Dextularia gramen @Orbigny ............]..]..|..|..|e.{ee[eo] «eles i “| Allee Textularia sagittula Defrance ....... ats vofeafeefee|eofeof sal al | SEN ae Alls ais | Vextularia subangulata @Orbigny....... dl (Gal bal bolloe| bel eallleallse Ke alee Ae pSppeplecta GHOUTH Bate ne ies scr ac. sea[oe[eefecfes]e-feefea] oafes] o. |e alte x | Nodosaria affinis (VOrbigny)........ 56640]| sallGalloclocliaaliaclgall called lon Ie ll oalle: 00 # | Nodosaria bacillum Defrance..... saa 36|lsel al Balle! bal oal| Gal gall spel dall dal bol heel lle] Ballsall anes Peale: a Nodosaria communis (VOrbigny) ....... ‘| collalioa|sullaclisaloall Salbel| usc boll Seco) oclisaliod Ballsclnecs| lies) Lea Ife | Nodosaria consorbrina v.emaciata (Reuss) Sal lyelsalisal Ge ealioal oulldalerasu lacl|MBay|SolMoa lacing Baltic 56] <3 | | Nodosaria sandbergeri (Reuss) ......-...: heel eal ae xt acl eel fal bo Breed eal | arc ral eval cred eral and es * | Nodosaria obliqua (Linné:........ eee SAISAGAl ecleal Gal ool koalladleeed ae eal : ine | ..| Vaginulina legumen (Linné)............ Salina sal eellealtos sal El ca eae af 2 ie lhiesen| arginula costata Batsch. ............... sifesfecfeclealee aes | lee 3 Merellaria gibba d’Orbigny.... ..........) cfc e[ocleofoe[ea[ee| = ane setae ele .| eis Oristellaria rotatula (Lamarck) .... 2.0...) ..)..)6 Ike 4|| oaloalls f ole. sel eel * | | : 5 bc ie eae 36 | = | */--] % | = sas ee alge VP Pad ect ig eleabelee Be . el (sa a a le Tes bes ie | x - | * Kile elewee) ce | Bo Poole: 36 50] on || <2 Ae | Oe a ee La onionina afinis Reuss | iS e 2. : Amphistegina lessonit d’Orbigny.........|.-|--)--|--/+-|--|+-| --{«-! -+ |. eae =| ’ PLANTAE. Viale est 8] | | | | | Ca polithus marylandicus Hollick............./.... lial: Hal hetereal is % «| Cai polithus marylandicus var. rugosus H. ....\.. 20. eee I =e = | eeenehan: Mono. xxxix, U.8.G@.S. ‘Cretaceous of N. J.,” Ulrich, see p. 222. 1°** Maastricht,” Ulrich, see p. 210. 82 THE EOCENE DEPOSITS OF MARYLAND CoRRELATION OF DEPosItTs. Numerous attempts have been made to correlate the Eocene deposits of Maryland with those of other areas. Not only has the attempt been made to establish the equivalency between the Maryland deposits and those of adjoining states to the north and south, but also with the more distant Gulf region and with Europe. That the conclusions reached by the various investigators have been widely at variance has already been shown in the Historical Review. Some have considered the strata to represent but a small part of the full Eocene series, while others have regarded them to embrace a considerable portion of the same. These diverse views will be discussed in detail in the subsequent pages. Two methods of correlation are possible, one based upon physical, the other upon biological criteria. The faunal and floral characteristics of the formations find, therefore, interpretation only as the physical fea- tures are clearly understood since the geological and geographical range of species is determined to a large extent by conditions of sedimentation. The physical characteristics of a formation, therefore, bear a close relationship to its contained faunas, and cannot be ignored in the corre- lation of the deposits. It is a well-recognized fact that the most trustworthy correlations are those based upon paleontological criteria, still the possibilities of varia- tion in the succession of organic forms in widely separated areas are so great that detailed correlation can seldom be satisfactorily attempted even where general equivalence is recognized. This is particularly true of the Eocene of the Middle Atlantic Slope where, as will be shown later, the range of species is quite different in certain particu- lars from that hitherto recognized in adjacent provinces. Such being the case, it is evident that whatever aid the physical criteria can afford should be employed in the interpretation of the Maryland Eocene de- posits. CORRELATION OF THE DEPOSITS WITHIN THE MIDDLE ATLANTIC SLOPE. It has generally been conceded that the Maryland and Virginia Eocene deposits constitute one and the same geologic province, a con- clusion which is well borne out by the fact that the strata are practically continuous and that the materials of the deposits and the fossils are \ fi MARYLAND GEOLOGICAL SURVEY 83 frequently the same. It is evident, however, that the Maryland beds especially form the lower horizons, while the Virginia deposits repre- sent more largely the upper horizons of the Pamunkey group. In other words, the Aquia formation is more strongly developed in Maryland and the Nanjemoy formation more strongly in Virginia, although the Nanjemoy formation is by no means lacking in Maryland and the same is true of the Aquia formation in Virginia. It is apparent that there must have been a gradual transgression of the Eocene deposits south- ward, since the Aquia formation gradually disappears under the Nanje- moy to the south of the Potomac; on the other hand, the Nanjemoy formation is entirely absent to the northeast of the Patuxent valley, while the Miocene deposits have gradually transgressed over the Eocene from the Potomac valley northward, so that successively older horizons are found in contact with the Miocene in passing from the Potomac basin northeastward toward Delaware, where the Miocene strata ulti- mately come to rest directly on the Cretaceous deposits. The result of this differential movement is to limit the area of outcrop of the Nanjemoy formation in Maryland to the southern counties of the state, while the Aquia formation is continued across the Chesapeake Bay into the eastern counties as well and finally disappears beneath the Miocene cover not far from the borders of Delaware. It is evident, therefore, that higher Eocene horizons are found in central and southern Virginia than appear in Maryland, a conclusion borne out by the fact that the Ostrea sellae- formis zone with its accompanying fossils is much more strongly repre- sented in the valleys of the Pamunkey and James rivers than in the Po- tomac basin. Thick beds of Ostrea sellaeformis are found in the former areas, while only a few representatives of this species appear in the upper zone of the Woodstock substage on the banks of the Potomac. CORRELATION OF THE DEPOSITS WITH THE EOCENE FORMATIONS OF THE GULF STATES. By common consent the extensive and diversified series of Eocene deposits found in the Gulf region has come to be regarded as the type not only for the Atlantic Coast region but for the entire country as well. Dr. Dall, basing his conclusions both on his own work and on that of others in this area, has recently adopted the following classification of 84 THE EOCENE DEPOSITS OF MARYLAND American Eocene horizons. The sequence of stages from above down- wards as given by him is as follows: Jacksonian, Claibornian, Chickasawan, Midwayan. , Paleontological Criteria. A comparison of the Maryland Eocene faunas with those represented in the Gulf area, which have primarily afforded the basis for the classi- fication above given, shows that the Maryland Atlantic Coast Eocene contains a great many species not represented in the Gulf, or of which the exact range there has not been well enough determined for com- parison (158 out of 207), while the majority of identical forms (49 in all) are of wide geological range, and are thus of little value in deter- mining the exact age of the deposits. There are enough distinctive species, however, as will be seen from a study of the table, to show that the Maryland Eocene must represent beyond any doubt the Chickasawan with both its upper and lower substages, and that from the Potomac basin southward through Virginia we also have in all probability the Lower Claibornian as well, with its Osirea sellaeformis zone. Whether higher or lower stages of the Eocene are represented in the Middle Atlantic Slope is a question that cannot be satisfactorily an- swered. There are no paleontological data that bear on this point, and the other evidence which may be brought forward cannot be regarded as conclusive. The non-fossiliferous zone at the base of the Aquia forma- tion may or may not be older than the Chickasawan, and the highest strata recognized as Eocene in central and southern Virginia have not been sufficiently studied to show whether they are or are not younger than the lower Claibornian. The following table contains the forms common to the Maryland and | Gulf areas: 1 The Upper Chickasawan as here used includes the Hatchetigbee and Woods Bluff (or Bashi) substages, while the Lower Chickasawan includes the Bells Landing (or Tusca- homa), Greggs Landing and Nanafalia substages as differentiated in Alabama and Mississippi. MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE VIII. Fria. 1.—CONTACT OF NANJEMOY AND AQUIA FORMATIONS IN VALLEY OF BEARD CREEK, ANNE ARUNDEL COUNTY. Fic. 2.—CONTACT OF NANJEMOY AND AQUIA FORMATIONS AT UPPER MARLBORO. VIEWS OF EOCENE SECTIONS. MARYLAND GEOLOGICAL SURVEY 85 MARYLAND. GULF REGION, | « S ‘ ee siglg|g@iE| sig SPECIES. 3 z zig a i se = at ee Ny ee er | ep a he Sie ewe Pepe Peas eae | ad ES lee eles |e Tornatellaca bella Conrad...... -....... Plewrotoma childreni Lea...............- he Beene ato ae ee Ve wane Borge Cancellaria graciloides Aldrich var....... CH Core ree Ee So AN MEST Borer pare ete Volutilithes petrosus (Conrad)........... at tt craw | bay % OMG aoe ba es Caricella pyruloides (Conrad)...........- els RSE 2 Fusus subtenuis Heilpriv...........---- Ke Ne age fs ‘ st x |. Fusus interstriatus Heilprin............ % % Sev attach Rel ee Trophon sublevis Harris...........-.-.. oe) SEE fies) Nome fe Levifusus trabeatus Conrad...........--)..-- x Prd Wee? *% Chrysodomus engonatus (Heilprin)...... 8 Horace: Py WAES Nad buruia penita var Conrad... 2.2 22.6.2 562) 22s Fusoficula juvenis (Whitfield)........... a ene a u Morio brevidentata (Aldrich)............ Ee paar TA) CaN Pen Cupraca smiths Aldrich. 2325. oe 22 2s Sh a % Pate x x Calyptraphorus trinodiferus Conrad...... * % “ee % 2 Turritella mortoni Conrad ............-. Ler poet. “ * a 5 x Turritella humerosa Conrad............. oN Rene # RRERSIIEEIOUT ULE (COUNLAG) =<. -.- (2 Fe arsc ce el ef # Wee nclewce Lunatia marylandica Conrad. .......... ‘ E 2: Calyptraea aperta (Solander)............ = + : Odostomia trapaquara (Harris).......--- Piet ven teas x? ? Niso umbilicata (Lea)....... 0.2... ae ae Oe es ae a elem both yr tepries Cadulus abruptus Meyer and Aldrich. Essie 2 # ae io, aa: <3 ce epee Mae 2 Corbula subengonata Dall.............-- 2 x Se ae % Be! oe Corbula aldrichi Meyer... 255. s.505.62%- x pane Hi ra5e # era: a Corbula oniseus Conrad............-.+.-- Ee Cet | Re) er eae s + MICLeIt Onna GONTAG™.. 022... 5s sen oes Es x ee 2 oo ee ee Sos Meretriz subimpressa (Conrad) ...-...... .... % Se ear te eisia se Bota a= Dosiniopsis lenticularis (Rogers).......-- Ad, aes ET Ge Pein aguiamar@lark 27.2 62. is vs 22's - = aes ie er Breen ie Lucina astartiformis Aldrich ...... RGEC AON LETS JONAR 0). open og oo cs soe * ae OS aes eee E Venericardia planicosta var.-regia’ Conrac + ..... SPR et #2 Modiolus alabamensis Aldrich............ 2 % . BP} CTS ELC TS aan ak 8, aE a tee a eas CREO Ville ae Me oan One o Peclen choctavensis Aldricli. .......... 2 Beth Warsi haa oF 3 eCten VONTISOME Clark so. s- seis i ee: 2 = eee ot ae Ostrea compressirostra Say ............. EA) eee ce Bea s Ostrea sellaeformis Conrad............. Scien. (Nie: Ei racds Pier ds 8S Zsa) Be 3 a2 Ostrea (Gryphaeostrea) vomer (Morton)... = Ee Li Mev guleyi dnd WE ae eerie Se Mi ak Nae 2 Pteria limula (Conrad)...............-. Pa ane ee ey 0) Pe Be eg Glycymeris idoneus (Conrad)........... at e i Ps “ g Trigonoarca decisa (Conrad) ............ ....- es Phe oh ae | Cucullaea gigantea Conrad Pee Dayoe (ROLES) 2. 22 os se ets heel Leda potomacensis Clark and Martin Nucula ovula Lea Sur, Nuk eee x x 2 x Balanophyllia desmophyllum M-E. and H oD ads PREC e) rae eal tee % % Eupsammia elaborata (Conrad) = oe z; 'The V. planicosta of the Middle Ailantie Slope has been divided by the authors of this paper into several species, the var. regia being limited to the Aquia stage. The other species have not been recognized in the Gulf region, although further investi- gation may show one or more of them to exist there. 86 THE EOCENE DEPOSITS OF MARYLAND In the above table and im the following discussion only the mollusca and corals are included. Many of the other species occur outside of the state, but they are not considered here because the facis at hand are not complete enough to base upon them any generalizations concerning the distribution of the forms or any deductions concerning their significance. _Aquia Stage—The Aguia stage includes the following species that have been found in the Lower Chickasawan of tHe Gulf, several of which, as will be seen by the table, also range downward into ithe Mid- wayan, while others pass upward into the Upper Chickasawan and even into the Claibornian. Some of these forms also, as will be further seen from an examination of the iable, are not confined alone to the Aquia, but range on into the Nanjemoy stage. The following Lower Chick- asawan species are found in the Aquia: Tornaicllaca balia Conrad. Pleursioma childreni Lea. Cancdlaria graciloides Aldrich. Volutilithes petrosus (Conrad). Caricella pyruloides (Conrad). Fusus subtenuis Heilprin. Trophon sublerizs Harris. Chrysodomus engonaius (Aeilprin). Pusojicula juveniz (Whitfield). Morio bresedentaia (Aldrich). Calyptraphorus trinediferus Conrad. Turritella mortonit Conrad. Turritdla humeroza Conrad. Lunatia marylandica Conrad. Calyptraca aperta (Solander). Niso umbilicata (Lea). (2) Odostomia trapaquara (Harris). Cadulus abruptus Meyer and Aldrich. Corbula subengonata Dall Cortula aldrichi Meyer. Merctriz ovata Conrad. Dosiniopsis lenticularis (Rogers). Lucina aquiang Clark. Pecten johnsoni Clark. Ostrea compressirostra Say- Glycymeris idoneus (Conrad). Cucullaca gigantea Conrad. Laia parva (Rogers). Nucula ovula Lea. Balanophyllia desmophylium M-E. and H. Eupsammia elaborata (Conrad). Of these forms a few only are restricted to the Lower Chickasawan, the remainder ranging on into the Upper Chickasawan and some on into the Claibornian as well The restricted forms are: Trophon sublecis Harris. Morio brevidentata (Aldrich). Dosiniopsis lenticularis (Rogers). Lucina aquiana Clark. Cucullaea gigantea Conrad. All of these species, except Cuculiaza gigantea, are confined to the Aguila stage. i See the discussion of this form in the chapter on Systematic Paleontology, p. 156. pe MARYLAND GEOLOGICAL SURVEY 87 The following species of the Aquia stage, on the other hand, have not been found below the Upper Chickasawan, viz.: Fusus interstriatus Heilprin. Peeten choctavensis Aldrich. Lucina uhleri Clark. Pteria limula (Conrad). Modiolus alabamensis Aldrich. : Of these, Pleria limula also oceurs in the Claibornian. The Aquia stage also contains several species that have not been:found below the Claibornian in the Gulf. They are: | Mesalia obruta (Conrad). Corbula oniscus Conrad. (7) Odostomia trapaquara (Harris). The following species occur in the Jacksonian, viz.: Cadulus abruptus Meyer and Aldrich. Peeten dalli Clark. Corbula oniscus Conrad. Ostrea (Gyphacostrea) vomer (Morton). None of them is of special significance. Before final conclusions are drawn from these comparisons, however, the fact must be taken into consideration that the Maryland beds have probably been examined at the present time more thoroughly and at a greater number of localities within the same limited area than those of the Gulf, and that some of the forms above mentioned may be shown upon further study to have a wider range in the Gulf than has been given to them. Due allowance must also be made for differences in judg- ment in the identification of species. At the same time, it is very clear that the species common to the Gulf and Middle Atlantic Slope differ materially in their geological range. This is evidently due in part to the difference in physical conditions in the two areas and also in part to migration. But after taking these facts into consideration it will be seen that the fauna of the Aquia is much more closely related to the Chickasawan as a whole than to either the Midwayan or Claibornian and that there is a somewhat closer resemblance to the Lower than to the Upper Chickasawan. The distance, however, between the two areas, the difference in physical conditions and the possibilities of migration are too great to admit of any attempt to draw exact parallelism between the substages. Nanjemoy Stage-—The Nanjemoy stage contains the following species found in the Lower Chickasawan of the Gulf, all but one of which (Cucullaea gigantea) also range on upward into the Upper Chickasawan or higher stages. They are: 88 THE EOCENE DEPOSITS OF MARYLAND Tornatellaea bella Conrad. — Corbula subengonata Dall. Volutilithes petrosus (Conrad). Corbula aldrichi Meyer. Levifusus trabeatus Conrad. WMeretrix ovata (Conrad.) Cypraea smithi Aldrich. - Pecten johnsoni Clark. Calyptraphorus trinodiferus Conrad. Glycymeris idoneus (Conrad). Lunatia marylandica Conrad. Cucullaea gigantea Conrad. Calyptraea aperta (Solander). Leda parva (Rogers). Cadulus abruptus Meyer and Aldrich. e The Nanjemoy stage contains the following species found in the Upper Chickasawan of the Gulf. They are: ' Tornatellaea bella Conrad. Meretrix subimpressa Conrad. Volutilithes petrosus (Conrad). Lucina astartiformis Aldrich. ‘Fusus interstriatus Heilprin. Lucina uhleri Clark. Levifusus trabeatus Conrad. F Modiolus alabamensis Aldrich. Cypraea smithi Aldrich. Pecten choctavensis Aldrich. Calyptraphorus trinodiferus Conrad. (7) Pecten johnsoni Clark. Lunatia marylandica Conrad. (7) Ostrea sellaeformis Conrad. Calyptraea aperta (Solander). Pteria limula (Conrad). Cadulus abruptus Meyer and Aldrich. - Glycymeris idoneus (Conrad). (7) Corbula subengonata Dall. Trigonoarca decisa (Conrad). Corbula aldrichi Meyer. Leda parva (Rogers). Meretric ovata Conrad. Leda potomacensis Clark and Martin. Among these species a few only are restricted to the Upper Chick- asawan. ‘They are: Fusus interstriatus Heilprin. Modiolus alabamensis Aldrich. Meretriz subimpressa Conrad. Pecten choctavensis Aldrich. Lucina astartiformis Aldrich. Leda potomacensis Clark and Martin. Lucina uhleri Clark. Of these forms Meretrix subimpressa, Lucina astartiformis and Leda potomacensis are found only in the Nanjemoy stage. The following species of the Nanjemoy stage are found in the Lower Claibornian: Volutilithes petrosus (Conrad). (7) Corbula subengonata Dall. Levifusus trabeatus Conrad. Corbula aldrichi Meyer. Pyrula penita var Conrad. Corbula oniseus Conrad. Mesalia obruta (Conrad). Ostrea sellaeformis Conrad. Lunatia marylandica Conrad. Pteria limula (Conrad). Calyptraea aperta (Solander). (7) Glyeymeris idoneus (Conrad). Cadulus abruptus Meyer and Aldrich. Trigonoarea decisa (Conrad). Among these forms Mesalia obruta is the only species that is confined ’ to the Lower Claibornian, while three others do not pass the limits of the Claibornian stage, viz., Pyrula penita var., Corbula oniscus and (?) Ostrea sellaeformis. ra are MARYLAND GEOLOGICAL SURVEY. g & ee SS no > Ra EOCENE, PLATE IX. Fra. 1.—POPES CREEK BLUFF SHOWING ZONE I7 OVERLAIN BY MIOCENE DIATOMACEOUS EARTH, e _. Se Sa See aa ee oe a Fig. 2.—RAILROAD CUT NEAR UPPER MARLBORO SHOWING OVERLAIN BY LATER DEPOSITS. VIEWS OF EOCENE SECTIONS. NANJE N 10Y FORMATION ," MARYLAND GEOLOGICAL SURVEY 89 Of the list above given, Levifusus trabeatus, Pyrula penita var., Ostrea sellaeformis and Trigonoarca decisa are confined to the Nanjemoy stage. The following Nanjemoy species have been found in the Upper Clai- bornian: Pyrula penita var, Conrad. Corbula oniseus Conrad. Lunatia marylandica Conrad. Ostrea sellaeformis Conrad. Calyptraea aperta (Solander). Pteria limula (Conrad). None of these species are confined to the Upper Claibornian and two of them only, Pyrula penita var. and Ostrea sellaeformis, are dis- tinctively Nanjemoy forms. The following species occur in the Jacksonian, viz.: Cadulus abruptus Meyer and Aldrich. Peeten dalli Clark. Corbula oniseus Conrad. Ostrea (Gyphaeostrea) vomer (Morton). None of them, however, has any special significance. It is thus shown that the Nanjemoy has faunal relationships both with the Chickasawan (and especially with the Upper Chickasawan) and with the Lower Claibornian. But in the Nanjemoy the lack of par- allelism in the succession of faunas between the Middle Atlantic and Gulf regions is even more noticeable than in the lower beds. The only conclusion which can be drawn is that the Nanjemoy of Maryland rep- resents such portion of the Chickasawan as lies above that represented by the Aquia, while the occurrence of the highly characteristic species, Ostrea sellaeformis, in the Nanjemoy stage in Maryland, although not so numerously or typically represented as in the still higher strata in central and southern Virginia, points to the possible Lower Claibornian age of the highest beds of the Maryland Eocene. Geological Criteria. The lthological and stratigraphical characteristics of the Eocene de- posits of the Middle Atlantic Slope afford some important criteria for the correlation of the strata. In the first place, the homogeneous nature of the materials, already referred to, is a significant feature, and indi- cates conditions undisturbed by important physical changes throughout the period of Eocene deposition. Again, the fact that the strata are so largely composed of secondary materials shows that the position of accumulation was in the vicinity of a coast reached by no large sediment- 90 THE EOCENE DEPOSITS OF MARYLAND bearing ‘rivers, while at the same time, for the most part, sufficiently removed from the coast-line to be unaffected by shore conditions. It is further evident that these deposits, which are so largely glauconitic, were very slowly accumulated, as has been shown in the case of the formation of greensand upon the beds of existing seas. . When we compare these conditions of accumulation on the Middle Atlantic Slope with the conditions that prevailed in the Gulf region during Eocene time marked differences appear. In the latter area numerous rivers, draining the interior of the continent, discharged large quantities of material throughout much of the Eocene, making the deposits highly diversified. Instead of the greensands and greenish and black clays of the Middle Atlantic Slope, which no longer to any great extent characterize the strata, are found coarser beds of sand and clay, often partly calcareous, which give every indication of more rapid accumulation. To compare, therefore, the 200 to 300 feet of green- sands and clays of the Middle Atlantic Slope with one or two subdi- visions of hardly equal thickness in the Gulf region would scarcely be attempted, even upon geological grounds. The strata of the Middle Atlantic Slope must be represented in the Gulf by deposits many times their thickness. The State Geological Survey of Alabama has estimated the tctal thickness of the Eocene beneath the Jacksonian at 1500 feet, 600 feet of this belonging to the Chickasawan and 450 feet to the Claibornian. The Lower Chickasawan is given a thickness of about 350 feet and the Upper Chickasawan a thickness of about 250 feet, the Bells Landing division of the former having a thickness of less than 150 feet. The paleontological evidence previously cited, combined with the geological data here presented, show the far greater thickness of the geologically contemporaneous deposits in the Gulf as compared with those of the Middle Atlantic States. Furthermore the general relations of the strata, occurring as they do between the Cretaceous and Neocene along both the Atlantic and the Gulf coasts, give some indication of the continental movements to which each province was subjected. Although the movements may not have been absolutely contemporaneous, they nevertheless afford satisfactory MARYLAND GEOLOGICAL SURVEY 91 criteria for the broad correlation of the deposits, their more exact par- allelism being determined on other and more definite grounds. European Equivalents. Several attempts have been made to correlate the deposits of the Middle Atlantic Slope with those of Europe. The earlier attempts in this direction are presented in the Historical Review. Most of the con- clusions reached were based on very insufficient data, the faunas being inadequately studied and even the sequence of deposits not being in most instances fully understood; but even after Conrad’ began his study of the Maryland Tertiaries and described more or less fully the rich faunas contained therein, his correlations were still based on very insuf- ficient knowledge. As the result of his investigations, he correlated the Eocene deposits of Maryland with the London Clay of England and the Calcaire Grossier of France. , Lyell, during his visit to America in 1841, examined somewhat hur- riedly the Eocene deposits of the Middle Atlantic area, but attempted no detailed correlation, stating, however, that the Tertiary formations which he saw “agree well in their geological types with the Eocene and Miocene beds in England and France.” Heilprin,” in an important publication on United States Tertiary Geology, discusses the equivalency of the European and American Ter- tiary formations. Jn a chapter dealing with “A Comparison of the Tertiary Mollusca of the Southeastern United States and Western Europe in Relation to the Determination of Identical Forms,” he refers to the species which Conrad, Lea and Meyer had regarded as analogous to Euro- pean forms, and also discusses in detail all those species which he regards as the same or which have certain points of resemblance. Referring to the more important of these forms in an earlier portion of the same volume (p. 13) he says: “If such comparisons are of any value strati- staphically, we may fairly look upon the Maryland Eocene deposits—the ijJour. Acad. Nat. Sci. Phila., vol. vi, 1830, pp. 205-217; Fossil Shells of the Tertiary, 1832, pp. iv, 9, 12, 13. 2Proce. Geol. Soc. London, vol. iv, 1845, pp. 563-564; Quart. Jour. Geol. Soc. London. vol. i, 1845, p. 429-450. . * Contributions to the Tertiary Geology and Paleontology of the United States, pp. $3-101. 92 THE EOCENE DEPOSITS OF MARYLAND Piscataway sands below, and the Marlborough rock above—as represent- ing a horizon nearly equal to that of the Thanet sands of England and the Bracheux sands of the Paris basin, or of the British Bognor rock (London clay). In either case they would be near the base of the Eocene series.” Dr. Dall, in a recent article on “A Table of the North American Tertiary Horizons, Correlated with one Another and with Those of Western Europe, with Annotations,” correlates the Maryland formations with the Suessonian of Europe. As the writers of this report believe, however, that the Eocene of Maryland represents more than the lower Chickasawan of the Gulf, they would assign to the Maryland Eocene a somewhat wider range in the European Eocene. It seems highly probable that the Londonian and even the Parisian in part are also represented. ‘The few identical species in the two areas have a wide range geologically, and are thus of little value for purposes of detailed corre- lation. Other species may ultimately be found in common, but more careful comparisons than have been made will be necessary to estab- lish this fact. Until such investigations have been made the correlation of the deposits on the two sides of the Atlantie can be at best only provisional. 118th Ann. Rept. U. 8. Geol. Survey, pt. ii, 1898, pp. 327-348. fi SYSTEMATIC PALEONTOLOGY POCENE REET EMM ONe teres Re eR crt are EN athe s pataeN Sra aye LI Ge wat ve HK. C. Case. TP USAC TOTS) Si Beene ee ees eC Ee ae Le Na ARE Se oa CHARLES R. HAsTMan. Eee Ova ODAC J Scr. a oinis winches amet ae een Ge se ogee. are we HK. ‘0. ULRICH. IOI TES CAs he eck sit ite aes eae let are W. B. Crark anp G. C. Martin. MOLLUSCOIDEA. BVA CHTO RP ODA... es an W. B. CrarK anpD G. C. Martin. HERP Ya OZ QA eset ais, otha aoe elena Sra ere esse apene Ley a Mata EK. O ULRIcz. C0 OB HNGT RU FUAC EAU. 2S Sie) oe clioleper Gini iy cemsene:s T. WAYLAND VAUGHAN. BCE MUN OIE RIM ATRAY ed oes W. B. Crark anp G. C. Martin. TP TRO) OVA OVA as ie ars en gc RR dco ua Mrmr R. M. Baae, JR. TP TEASED VAS Ot aR oar gta tng ce ent OLE! Poe Yb rea aA ARTHUR HOLLICK. % VERTEBRATA. CLass R E ears LIA. Order CROCODILIA. Suborder ENSUCHIA. Family CROCODILIDAE. Genus THECACHAMPSA (CROCODILUS) Cope. THECACHAMPSA sp. Plate X, Figs. 1, 2. Description.—A very large vertebra, probably dorsal, gives evidence of an animal of considerable size. ‘The anterior face is deeply concave, and the rounded posterior face marked by a deep pit. It is impossible to determine whether the vertebra belongs to any one of the species below described and which are based on the teeth and jaws alone, and it therefore seems undesirable to assign a specific name to it. Occurrence—AQuia Formation. Liverpool Point. Collection—Maryland Geological Survey. THECACHAMPSA SERICODON (?) Cope. Plate X, Fig. 3. Thecachampsa sericodon Cope, 1867. Proc. Acad. Nat. Sci. Phila., p. 145. Thecachampsa sericodon Cope, 1869. Proc. Acad. Nat. Sci. Phila., p. 12; Amer. Nat., p. 91. Thecachampsa sericodon Cope, 1871. Trans. Amer. Phil. Soc., vol. xlv, p. 64, pl. v, figs. 7and 8. (Pages 1-104 appeared in 1869.) Thecachampsa sericodon Cope, 1875. Proc. Acad. Nat. Sci. Phila., p. 363. Description—A long slender tooth with a strong root represents this or an allied species. The specimen is water-worn and it is impossible to determine its characters exactly. Occurrence—AQuiIA Formation. Clifton Beach. Collection—Maryland Geological Survey. 96 SYSTEMATIC PALEONTOLOGY THECACHAMPSA CONTUSOR Cope. Plate X, Fig. 4. Thecachampsa contusor Cope, 1867. Proc. Acad. Nat. Sci., Phila., p. 143. Description——This species was recognized by Cope as of doubtful value and he considered the forms placed here as possibly belonging to T. antiqua. A specimen in the collection has the characters assigned to contusor except that the section of the base is elliptical instead of rounded, and certainly does not belong to antiqua, so that it may be placed here provisionally. _ Occurrence—Agquia Formation. Aquia Creek. Collection.—Maryland Geological Survey. THECACHAMPSA MARYLANDICA Clark. Plate X, Fig. 5. Thecachampsa marylandica Clark, 1595. Johns Hopkins Univ. Circ., vol. xv, p. 4. Thecachampsa marylandica Clark, 1896. Bull. 141, U. 8. Geol. Survey p. 58. pl. vii, fig. 1. Description.—The specimen is a fragment of the jaw, described as “moderately thick, the single complete and one partially preserved alveoh not far removed from one another. Teeth with elongate, shghtly curved, conic crowns; basis circular, its diameter about one- third the length of the tooth; apex acute, circular; surface with fine prolongations and striations.” Clark, 1895. Dimension of the tooth 38 mm., diameter at base 12 mm. Occurrence.—AQuia Formation. Clifton Beach, Upper Marlboro. Collections.—Johns Hopkins University, Maryland Geological Survey. COPROLITE. Plate X, Fig. 6. Coprolite Clark, 1595. Bull. 141, U. 8. Geol. Survey, p. 60, pl. vii, fig. 4. Description—A reptilian coprolite of very perfect form. It is only one-half preserved. These coprolites are rather common in the forma- tion. Occurrence—AQgutia Formation. Clifton Beach. Collection Johns Hopkins University. MARYLAND GEOLOGICAL SURVEY 97 Orde TESTUDENATA. Suborder CRYPTODIRA. Family CHELONIIDAE. Genus EUCLASTES Core. KEUCLASTES (?) sp. Clark. Plate X, Fig. 7. Huclastes (7?) sp. Clark, 1895. Johns Hopkins Univ. Cire., vol. xv, No. 4. Buclastes (7) sp. Clark, 1896. Bull. 141, U. 8. Geol. Survey, p. 59. Description.—* Several fragments from the carapace of a large sea turtle were found at Clifton Beach, but they were not sufficiently well preserved to identify the genus with certainty. Fragments of the costals show that the surface was smooth and the edges of the plate more or less rounded. The shields were relatively thin.” Clark, 1895. Occurrence—AQuia ForMATION. Clifton Beach. Collection — Johns Hopkins University. Suborder TRIONYCHIA. Family TRIONYCHIDAE. Genus TRIONYX Geoffroy. TRIONYX VIRGINIANA Clark. Plate XI, Figs. 1, 2. Trionyx virginiana Clark, 1895. Johns Hopkins Univ. Circ., vol. xv, No. 4. Trionyx virginiana Clark, 1896. Bull. 141, U. S. Geol. Survey, p. 59, pl. viii, figs. la and 1b. Descriplion.—Fragments of costals with tuberculated and ridged sur- faces, characteristic of the genus T’rionyx. The longitudinal ridges are. prominent, at times irregular and inosculate; relatively remote and separated by intervals of about twice their width; generally entirely disappear near the margins of the plates. Length of the largest fragment 130 mm., width 45 mm., thickness 18 mm. 6 ‘ 98 SYSTEMATIC PALEONTOLOGY This fragment is evidently one of the terminal costals with no pro- jecting portion of the rib beyond the plate. Occurrence-—AQUuIA Formation. Aquia Creek. Collections.—Wagner Free Institute of Science, Johns Hopkins Uni- versity, Maryland Geological Survey. CLass PISGES: Order ELASMOBRANCHIL. Suborder TECTOSPONDYLI. Family MYLIOBATIDAE. Genus MYLIOBATIS Cuvier. The following remarks on the crushing pavement-teeth of the great “ Hagle-rays,” so abundant in the American and European Eocene, are extracted from an important paper on sharks’ teeth from the English Eocene by A. 8S. Woodward." . “The dentition of each jaw in this genus | Myliobatis| comprises large, flattened, hexagonal teeth, arranged in seven antero-posterior series. In very young individuals, the teeth are all approximately of equal size, but quite early in life the median teeth begin to become rela- tively very broad, and as the animal grows, this disproportion of the median teeth gradually becomes greater and greater. When unworn or unabraded, the grinding surface of the teeth is covered with a thin enamel-like layer of gano-dentine, usually marked with antero-pos- teriorly directed striations; but when this layer is removed, the tooth has a punctate appearance, owing to the exposure of the vertical nutri- tive canals traversing the underlying vascular dentine. In naming the fossils, it is thus necessary to take into account the size of the specimen, and remember that the surface markings depend on the state of preser- vation. It is also necessary to note that the dental plate of the lower jaw is flat, while that of the upper jaw curves round the supporting cartilage.” 1 Proce. Geol. Assoc., vol. xvi, 1899, p. 3. ote MARYLAND GEOLOGICAL SURVEY 99 MYLIOBATIS COPEANUS Clark. Plate XII, Figs. 1, 2; Plate XIII, Bigs. 2a, 2b, 6, Ya, Yb. Myliobatis copeanus Clark, 1895. Johns Hopkins Univ. Cire., vol. xv, p. 4. Myliobatis copeanus Clark, 1896. Bull. 141, U. 8. Geol. Survey, p. 61, pl. vii, figs. 3a, 8b. Description —Dentition large and massive, the coronal contour strongly curved antero-posteriorly, and moderately arched from side to side in the upper jaw, but only very slightly so in the lower.. Trans- verse sutures strongly and regularly concave toward the front in upper median teeth, less so in those of lower jaw, where they are sometimes slightly serrated. Upper median teeth relatively longer than the lower, but often variable in this respect; as a rule they are about five times as broad as they are long in the adult. Lateral teeth long and narrow, arranged parallel with the main axis. Surface smooth and polished when unabraded, but becoming longitudinally striated and fissured when worn. Oral surface of lower dental plate exhibiting a slight longitudinal depression along the central portion, and under surface cor- respondingly thickened, the latter having an arcuate contour from side to side. This species is very abundant in the Eocene of Maryland and Vir- ginia, but is apparently unknown beyond the limits of these states. A large series of specimens has been collected, thus facilitating a compari- son of successive growth stages, and of variations due to wear and other causes. It is a remarkably massive form, the thickness of the median teeth equalling that of I. pachyodon from the Miocene, and the trans- verse section being very much the same. In the latter species, how- ever, the transverse sutures of the median teeth are nearly straight, being only slightly curved backward at the extremities, whereas the present form is distinguished by the median sutures being uniformly concave toward the front. The curvature of the suture-lines is usually more pronounced in the upper dentition than in the lower, and in the newest-formed teeth than in those more anteriorly situated. The me- dian teeth of the lower dental plate are also somewhat shorter, as a rule, than those in the upper jaw, and the coronal contour is much less arched from side to side. 100 SYSTEMATIC PALEONTOLOGY Dental pavements are not uncommon showing as many as nine longi- tudinal series of median teeth intact (Plate XIII, Figs. 6, 7). One of the largest upper dental plates examined is from the Aquia Formation of Potomac Creek, and in this the median teeth are 6.5 cm. wide, 1.5 cm. long, and 3 em. thick, not including the root. The antero-posterior curvature of the coronal surface is so great as to form a nearly perfect semicircle, having a diameter of 8 em. and a periphery of over 12 cm. Nine of the median teeth are preserved in regular series, together with a portion of the lateral series on both sides. There is considerable re- semblance between this mpeeles and M. holmesii from the Eocene of South Carolina. The type consists of fragmentary dental plates of the upper and lower jaws. Occurrence—NANJEMOY ForMATION. Woodstock. Aguta Forma- _TI0N. Clifton Beach, Liverpool Point, Aquia Creek, Potomac Creek. Collections—Johns Hopkins University, Maryland Geological Survey. MYLIOBATIS MAGISTER Leidy. Plate XII, Fig. 3; Plate XIII, Figs. la, 1b. Myliobatis magister Leidy, 1876. Proc. Acad. Nat. Sci. Phila., p. 86. Myliobatis magister Leidy, 1877. Jour. Acad. Nat. Sci. Phila., N. 8., vol. viii, p. 233, pl. xxxili, fig. 7. Myliobatis holmesiti Woodward, 1899. Cat. Foss. Fishes, Brit. Mus., pt. i, p. 122 Description.—Dentition very large and massive, the median teeth at least six times wider than long, their sutures curved backward near the lateral margins, and sometimes very faintly so in the central area. Coronal contour of upper dental plate uniformly arched from side to side, and also to an equal extent in a longitudinal direction; lower dental plate less curved antero-posteriorly than the upper, and slightly de- pressed along the median line. Surface smooth when unworn, or with fine superficial strie slightly convergent toward the front. This gigantic species, which is exceeded in size only by the Egyptian M. pentoni, is not actually known to occur in Maryland, being confined, so far as known, to the Eocene Phosphate Beds of South Carolina. It is noticed in this connection, however, because of the interest attached MARYLAND GEOLOGICAL SURVEY 101 to the original, which is the largest specimen hitherto reported from this country. The figured specimen was found at Ashley, South Caro- lina, and is preserved in the Museum of Comparative Zoology at Cam- bridge, Massachusetts. The strong curvature of the oral surface, which is equal in both longitudinal and transverse directions, together with the proportions and wavy sutures of the median teeth prove it beyond all doubt to be the upper dentition, previously unknown, of a species founded by Leidy on a unique lower dental plate from the same locality, to which he applied the name M. magister. Leidy himself, and follow- ing him A. 8. Woodward, were of the opinion that the type-specimen might represent the lower dentition of J/. holmesii Gibbes, which was described from a supposed upper dental plate with strongly curved su- tures. The specimen in the Cambridge collection, however, completes our knowledge of the dentition of I. magister, and we must look else- where for the opposing dentition of Gibbes’ species. The latter, as has already been intimated, appears to be only very slightly different from A. copeanus of this state. The type consists of a lower dental plate. Collections —Philadelphia Academy of Natural Sciences, Museum of Comparative Zoology, Cambridge. Genus AETOBATIS Miller and Henle. In this genus there is but a single series of very broad, flat teeth, those of the upper jaw only differing from the median teeth of IMylio- batis in their truncated lateral ends. The lower dentition is very nearly flat, and the teeth are all more or less strongly curved or angularly bent in the middle. The coronal surface is smooth or slightly striated, and the attached surface of the root longitudinally ridged or grooved. Woodward* remarks that “In this genus there is much less variability in the relations of the length and breadth of the teeth according to age than in Myliobatis; but the form of the lower teeth is so inconstant, that species cannot be determined upon the evidence of the lower denti- tion alone.” ' Cat. Foss. Fishes, British Museum, pt. i, 1889, p. 128. 102 SYSTEMATIC PALEONTOLOGY AETOBATIS ARCUATUS Agassiz. - Plate XIII, Figs. 3a, 3b, 8. Aetobatis arcuatus Agassiz, 18453. Poiss. Foss., vol. ili, p. 327. Aelobatis arcuatus Cope, 1867. Proc. Acad. Nat. Sci. Phila., p. 139. Aetobatis prefundus Cope, 1867. Loc. cit., p. 139. Aetobatis arcuatus Leidy, 1877. Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. viii, p. 245, pl. xxxi, figs. 14-18. : Aetobatis profundus Leidy, 1877. Loe. cit., p. 246, pl. xxxi, figs. 19, 20. Description.—This species is known only by fragments belonging chiefly to the lower dentition, and consequently cannot be accurately defined. Founded originally on detached teeth from the Miocene of Switzerland, it has been recognized by Cope and Leidy from the corre- sponding horizon in Maryland, but has not been hitherto reported from the Eocene. It would appear to be very rare in the latter formation, as only a few detached teeth have been collected by the Maryland Geo- logical Survey. A number of Miocene forms from Charles county are figured by Leidy (loc. cit., 1877, pl. xxxi), who very plausibly suggests that the narrow rounded crowns described by Cope as A. profundus are in reality only worn anterior teeth belonging to the species under con- sideration. Other species of Aetobatis occur in the Eocene of New Jer- sey and South Carolina. Occurrence.—N ANJEMOY FoRMATION. Popes Creek. AQqutA ForMma- TION. Aquia Creek. Collection.—Maryland Geological Survey. Suborder ASTEROSPONDYLI. Family CESTRACIONTIDAE. Genus SYNECHODUS Woodward. This genus of Cestraciont sharks is known by the nearly complete dentition and parts of the skeleton in the Lias of England, where it accompanies such allied forms as Hybodus, Acrodus, etc., and detached teeth have also been described from the Cretaceo-Tertiary of New Zea- land. Its remains have not been heretofore reported, however, from strata of undoubted Tertiary age, and the following species may be re- garded as the latest survivor of the genus of which we have any record. = a ee ew ——————————— te tesiaer te MARYLAND GEOLOGICAL SURVEY 105 SYNECHODUS CLARKIL nN. sp. Plate XIV, Figs. 5a, 5b, 5c. Description.—VTeeth of small or moderate size, but of relatively stout proportions, and symmetrical. Median cone sharply recurved, gently tapering, smooth, convex on both faces, and cutting edges not conspicu- ously defined; on either side, two much smaller cones, the external one being the lesser of the two. Root massive and somewhat turgid, pro- duced in the are of a circle on the inner face, and flat below; nutrient foramen small. The total height of the tooth, oriented in its natural position, is 7 mm. The distance from apex to base of crown, measured along its recurved outer face, is 6 mm. The width and thickness of the crown at its base are equal, amounting to 3 mm., whereas the corresponding measure- ments of the root, taken at their maximum, are 8 mm. and 4 mm. re- spectively. This unique tooth appears sufficiently well characterized, notwith- standing that the lateral cones are broken off above the base, to warrant recognition as a distinct species, and it may be fittingly named in honor of the State Geologist. Much interest is attached to the fact of its coming from a Tertiary horizon. Occurrence—AQuia Formation. Liverpool Point. Collection Maryland Geological Survey. Family LAMNIDAE. Genus ODONTASPIS Agassiz. The teeth of this genus are very similar to those of the Cretaceous Scapanorhynchus, a survivor of which has been recognized in Mitsiku- rina of the present day; and they are also, as remarked by Agassiz, very difficult to distinguish from those of Zamna. The crown is high, nar- row and compressed in all except a few hindermost teeth, and adjacent to it are one or two pairs of lateral denticles, generally sharply pointed. The anterior teeth are especially high-crowned, comparatively large anc slender, with a much produced bifurcated root. 104 SYSTEMATIC PALEONTOLOGY ODONTASPIS ELEGANS (Agassiz). Plate XIV, Figs. 2a, 2b, 2c, 3a, 3b, 3c. Lamna elegans Agassiz, 1843. Poiss. Foss., vol. ili, p. 869, pl. x10, fig. 24. Lamna elegans Gibbes, 1849. Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. i, p. 196, pl. xxv, figs. 98-102 (? figs. 96, 97). Lamna elegans Emmons, 1858. Rept. Geol. Surv. N. Car., p. 289, figs. 70, 71. Lanna elegans Noetling, 1885. Abh. Geol. Specialk. Preussenu. Thuring. Staaten, vol. vi, pt. 3, p. 61, pl. iv. x Odontaspis elegans Woodward, 1889. Cat. Foss. Fishes, British Mus., pt. i, p. 661. Odontaspis elegans Clark, 1895. Johns Hopkins Univ. Circ., vol. xv, p. 4. — Odontaspis elegans Clark, 1896. Bull. 141, U. 8. Geol. Survey, p. 62. Odontaspis elegans Woodward, 1899. Proc. Geol. Assoc., vol. xvi, p. 8, pl. i, figs. 15-18. Description-—Anterior teeth with a very high and narrow crown, only slightly curved, the inner face strongly striated longitudinally, and scarcely flattened in the middle. A single pair of small, prickle-like lateral denticles, and nutritive foramen on the prominent inner side of the root placed in a deep cleft. Lateral teeth with an almost equally slender, but less elevated crown, which is similarly striated and flanked with relatively large, slender denticles. ‘The two branches of the root are long, compressed and generally pointed. This is the most abundant of all Eocene sharks’ teeth in Maryland and Virginia, but is of rare occurrence in the Miocene. It is a some- what smaller form than O. macrota, and the anterior teeth of the two species are so much alike that it is difficult to separate them. ‘This is especially true of worn specimens (Plate XIV, Fig. 2) where the den- ticles are wanting and the striation of the inner face inconspicuous, and chief reliance must be placed on the narrowness of the crown. The anterior teeth sometimes exceed 4 cm. in total height. Dr. F. Noethneg, and following him, Jaekel and Smith Woodward, have been chiefly in- strumental in reconstructing the dentition of this and other species of Odontaspis. The type consists of teeth and associated vertebrae in the museum of College of Surgeons, London. Occurrence. AqgutiA Formation. Aquia Creek, Fort Washington, Liverpool Point. Collections. Johns Hopkins University, Maryland Geological Survey. 1On the striation of Selachian teeth, see J. Probst, Wartt., Jahresb., vol. xv, 1859, p. 100. MARYLAND GEOLOGICAL SURVEY 105 ODONTASPIS MACROTA (Agassiz). Plate XIV, Figs. 4a, 4b. Otodus macrotus Agassiz, 1843. Poiss. Foss., vol. iii, p. 278, pl. xxxii, figs. 29-31. Lamna elegans Agassiz, 1843. Tom. cit., p. 289, pl. xxv, figs. 1-7; pl. xxxviia, figs. 58, 59. Lamna compressa Agassiz, 1845. Tom. cit., p. 290, pl. xxxviia, figs. 65-42. Lamna compressa Gibbes, 1849. Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. i, p- 19%, pl. xxy, figs. 107-112. Otodus macrotus Gibbes, 1849. Tom. cit., p. 200, pl. xxvi, figs. 2, 145, 144. Lamna compressa Emmons, 1858. Rept. Geol. Sury. N. Car., p. 240, figs. 72, ; Odontaspis macrota O. Jaekel, 1895. Mém. Comité Géol., St. Petersb., vol. ix, pp. 115 29; pl. i, fies: 8-17. Odontlaspis macrota Woodward, 1899. Proce. Geol. Assoc., vol. xvi, p. 9, pl. 1, figs. 19, 20. Description—Anterior teeth much compressed, the inner face with fainter, more wavy and more interrupted strive than those of O. elegans. Typical lateral teeth much compressed, crown with sharp cutting edges and a faintly striated inner face; outer coronal face gently convex. A single pair of large and broad lateral denticles, usually rounded, but sometimes obtusely pointed. This species is tolerably abundant in the Eocene of various localities in Maryland and Virginia, especially at Liverpool Point on the Potomac river. The lateral teeth rarely exceed 2.5 cm. nor the anterior 3.5 cm. in total height. Occurrence.—N ANJEMOY ForMATION. Woodstock. Aguia ForMaA- TION. Aquia Creek, Fort Washington, Liverpool Point. Collection—Maryland Geological Survey. ODONTASPIS CUSPIDATA (Agassiz). Plate XIV, Figs. la, 1b, 6a, 6b. Lanna cuspidata Agassiz, 1845. Poiss. Foss., vol. ili, p. 290, pl. xxxviia, figs. 45-50. Lamna cuspidata Gibbes, 1849. Jour. Acad. Nat. Sci. Phila., 2nd-ser., vol. i, p. 197, pl. xxv, figs. 105-106. Lamna clavata Agassiz, 1856. Rept. Pac. R. R. Explor. and Sury., vol. v, p. 316, pl. i, figs. 19-21. Lamna clavata Agassiz, 1856. Amer. Jour. Sci., ser. ii, vol. xxi, p. 275. Odontaspis hopei Noetling, 1885. Abh. Geol. Specialk., Preussen u. Thiiring, Staaten, vol. vi, pt. 3, p. 71, pl. v, figs. 1-3. Odontaspis cuspidata Woodward, 1899. Proc. Geol. Assoc., vol. xvi, p. 7, pl. i, figs. 12-14. 106 SYSTEMATIC PALEONTOLOGY Description.—Teeth scarcely distinguishable from those of O. elegans except by their shghtly smaller size and by the absence of strie upon the inner coronal face. Anterior teeth much elevated and narrow, but ‘moderately stout. Lateral denticles of both anterior and lateral teeth occasionally flanked by a smaller secondary pair. . Teeth belonging to this species accompany those of O. elegans and QO. macrota in various localities of Maryland and Virginia, but are less numerous than either of these forms. From the Miocene of this state, very few examples have been obtained. In some specimens two well- - developed pairs of lateral denticles occur, as shown in Plate XIV, Fig. 1, and also in Figs. 86a and 87a of Emmon’s North Carolina Geological Survey Report (1858), p. 241. Occurrence—NaNsJEMOY Formation. Popes Creek, Woodstock. Aquta Formation. Mattawoman Creek, Fort Washington, Liverpool Point. Collection —Maryland Geological Survey. Genus OTODUS Agassiz. Nearly all the species assigned by Agassiz to this genus have been distributed by subsequent authors among Lamna, Odontaspis and Oxyrhina. Noetling even goes so far as to refer the type-species O. obliquus, to the genus Carcharodon, although the coronal margin is never distinctly serrated. The best modern opinion is that the pecu- harly robust teeth belonging to this species should be provisionally re- tained in the place provided for it by its founder, and along with this should be ranged a second, somewhat smaller species occurring in Eng- land and Russia, known as O. trigonalis (Jaekel). OTODUS OBLIQUUS Agassiz. Plate XV, Figs. 1-4c¢. Otodus obliquus Agassiz, 1848. Poiss. Foss., vol. iii, p. 267, pl. xxxi, pl. xxxvi, figs. 22-27. Otodus obliquus Gibbes, 1849. Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. i, p. 199, pl. xxvi, figs. 131-137. Lanna acuminata Gibbes, 1849. Loe. cit., p. 197, pl. xxv, figs. 118, 114 (? not fig. 115). Lamna (2) obliqua Clark, 1895. Johns Hopkins Uniy. Cire., vol. xv, p. 4. Lamna (?) obliqua Clark, 1896. Bull. 141, U. 8. Geol. Survey, p. 61. Otodus obliquus Woodward, 1899. Proc. Geol. Assoc., vol. xvi, p. 10. ; rn MARYLAND GEOLOGICAL SURVEY 107 Description.—* Teeth robust, attaining to a very large size; crown moderately compressed, sharply pointed, with one broad acuminate pair of lateral denticles, and, in the smaller teeth, an additional pair of more slender denticles. Outer coronal face flat or slightly convex, without folds; inner face smooth. Inner face of the root prominent, and nutri- tive foramen not sunk ina groove.” Agassiz, 1843. These very robust teeth attain a large size, the crown sometimes meas- uring 5 em. in height (cf. Plate XV, Fig. 4), but the majority of speci- mens do not exceed 3 cm. in total height. The anterior teeth (Plate XV, Fig. 1) are narrow and erect, with rather deeply cleft root, and frequently with only one or no lateral denticles; they are sometimes diffi- cult to distinguish from the anterior teeth of Odonlaspis macrota. The lateral teeth are distinguished by their broader, more compressed and usually obliquely directed crowns. The small hindermost teeth are often extremely broad-based, but here as elesewhere in the jaws, much individual variation occurs. It does not appear possible, however, to recognize more than a single species in the American Tertiaries. Nu- merous examples are found in the Eocene of Maryland, Virginia, New Jersey, and the Carolinas. Occurrence—AQuia Formation. Jiverpool, Aquia Creek, Glymont. Collections —Maryland Geological Survey, Johns Hopkins University. Genus CARCHARODON Agassiz. The teeth of Carcharodon attain enormous size, exceeding those of all other Selachian genera. They are triangular, usually erect, and re- semble those of Oxyrhina and Olodus except that the edges of the com- pressed crown are always serrated. Some species are without lateral denticles, others have a single pair, serrated like the crown. The genus enjoyed a world-wide distribution during the Eocene and Miocene, and was exceedingly abundant in various localities of both hemispheres. In the South Carolina Phosphate Beds the teeth are so numerous as to be of no mean commercial importance. 108 SYSTEMATIC PALEONTOLOGY CARCHARODON AURICULATUS (Blainville). Squalus auriculatus Blainville, 1818. Nouv. Dict. d’Hist. Nat., vol. xxvii, p. 384. Carcharodon acutidens Gibbes, 1847. Proc. Acad. Nat. Sci. Phila., p. 267. Carcharodon angustidens Gibbes, 1848. Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. i, p. 145, pl. xix, figs. 10-18, pl. xx, pl. xxi, figs. 37-38. Carcharodon acutidens Gibbes, 1848. Tom. cit., p. 146, pl. xxi, figs. 39-41. Carcharodon rectus Agassiz, 1856. Rept. Pac. R. R. Explor. and Survy., vol. v, p. 316, pl. i, figs. 39-41. a Carcharodon rectus Agassiz, 1856. Amer. Jour. Sci., ser. ii, vol. xxi, p. 274. Carcharodon crassidens Etamons, 1858. Rept. Geol. Surv..N. Car., p. 233, fig. 59a. Carcharodon contortidens Emmons, 1858. Loe. cit., p. 233, fig. 60. Carcharodon angustidens Leidy, 1877. Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. Vili, p. 253. Carcharodon angustidens Noetling, 1885, Abh. Geol. Specialk., Preussen u. Thar. Staaten, vol. vi, pt. 3, p. 82, pl. vi, figs. 1-3. Description ——*Teeth robust, comparatively narrow, with a pair of broad lateral denticles; outer coronal face flat or slightly convex. Lat- eral denticles especially large in the lateral teeth, which have a very narrow oblique crown.” Blainville, 1818. This species is apparently very rare in the Maryland Tertiaries, only a single fragmentary example having been obtained from the Eocene of Popes Creek, and very few from the Miocene. Owing to its imper- fection, no figure is given of the Eocene tooth, but it is to be noted that the lateral denticles are very feebly developed, so that the reference to this species is not absolutely certain. Occurrence.—N ANJEMOY Formation. Popes Creek. Collection Maryland Geological Survey. Family CARCHARIIDAE. The teeth of this family of “man-eating sharks” are very abundant in the Tertiary of all countries, and closely resemble those of the LamnipsrE. They differ from the latter however, in their internal struc- ture, being hollow in the center throughout life, and with minute tubules radiating from the pulp-cavity across the dentine. The teeth are so much alike in existing genera that when found in the detached fossil condition it is often impossible to separate them. For instance, the upper teeth of Hypoprion are scarcely distinguishable from those of Galeus, and isolated teeth of Galescerdo and Sphyrna are difficult to dis- tinguish from those of Carcharias. It is rather surprising that the last- MARYLAND GEOLOGICAL SURVEY 109 named genus does not appear to be present in the Maryland Kocene, and the teeth of Galeocerdo contortus, although very abundant in the corre- sponding horizons of Virginia and South Carolina, are likewise wanting in this state. //emipristis serra is another common form in the Carolina Eocene, and also in the Miocene of the Atlantic Slope extending as far north as Gay Head, Massachusetts, but is apparently unknown in the Eocene of Maryland and Virginia. Genus GALEOCERDO Miiller and Henle. The teeth of this genus are serrated on both margins, have the pos- terior edge deeply notched, and the apex more or less sharply inclined backward. As already remarked, some species are very difficult to dis- tinguish from Carcharias, and in the case of the teeth referred to G. minor by Gibbes, Emmons and Cope, comparisons show that these really belong to species of Carcharias. GALEOCERDO LATIDENS Agassiz. Plate XIV, Fig. 8. Galeocerdo latidens Agassiz, 1848. Poiss. Foss., vol. iii, p. 231, pl. xxvi, figs. 22, 23 (? figs. 20, 21). Galeocerdo latidens Gibbes, 1849. Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. i, p. 192, pl. xxv, figs. 59-62. Description —*< Teeth broad, mostly low-crowned, the largest meas- uring about .024 cm. across the base. Anterior coronal margin only slightly arched, except near the apex; apex above the posterior notch small, narrow; margin below the posterior notch long, straight and much inclined; root large. Serrations of the coronal margin very prominent.” This species is not uncommon in the Maryland Miocene, but as yet only a single example has been obtained from the Eocene of this state. Its preservation is not so good as might be desired, and it is rather under the average size attained by this species. Occurrence.—N ANJEMOY Formation. Woodstock. Collection Maryland Geological Survey. Genus SPHYRNA Rafinesque. The small teeth belonging to this genus are similar in both jaws, oblique, with a slight posterior notch, and margins smooth or serrated. Their resemblance to the teeth of Carcharias has already been noted. 110 SYSTEMATIC PALEONTOLOGY SPHYRNA PRISCA Agassiz. Plate XIV, Figs. Ya, 7b. Sphyrna prisca Agassiz, 1843. Poiss. Foss., vol. iii, p. 234, pl. xxvia, figs. 35-50. Sphyrna prisca Gibbes, 1849. Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. i, p. 194, pl. xxv, figs. 88-90. Lamna compressa (pars) Emmons, 1858. Rept. Geol. Surv. N. Car., p. 240, figs. 79-81. (7) Sphyrna denticulata Emmons, 1858. Loe. cit., p. 241, fig. 84a. Description.—Teeth small, broad, gently oblique, often erect, with finely serrated edges. This species is very abundant in the Eocene of South Carolina and “Miocene of Maryland, but only two or three rather imperfect examples have been obtained from the Eocene of this state. There was also found one doubtful tooth, which may possibly belong to a distinct species. Occurrence—AQutia FormMatTIon. Liverpool Point. Collection —Maryland Geological Survey. SELACHIAN VERTEBRAE. Detached vertebrae of the Asterospondylic type, consisting of calcified cartilage and therefore not well adapted for preservation, are occasionally met with in the Eocene of Clifton Beach and a few other localities in Maryland and Virginia. Some of the larger ones are but slightly con- cave on both faces, and belong without doubt among the La nips, possibly to Otodus or Carcharodon. Detached vertebrae of both Elas- mobranch and Teleost fishes are much more common in the Miocene than Eocene, and represent a considerable variety of forms. In Plate XII, Figs. 7a and 7b are represented detached vertebrae of an indeter- minate species of bony fishes. SUBCLASS Tse LE OST OMI Order ACTINOPTERYGII. Remains of bony fishes are very rare in the Tertiary of the Middle Atlantic Slope, and are confined to detached vertebrae, otolites and por- tions of the dentition. A few species founded on detached teeth from MARYLAND GEOLOGICAL SURVEY 111 the Eocene of South Carolina have been described by Leidy,’ and a singular bone from the same horizon supposed to belong to Platax is figured by Gibbes.” Cope records in all only one species of Actinoptery- gians from the Miocene of Maryland (Sphyraena speciosa), and five from the same horizon in New Jersey, as follows: Sphyraena. speciosa, S. siloviana, Phasganodus gentryi, Crommyodus trregularis, and Phyllo- dus curvidens. The last-named genus is of exceptionally rare oceur- rence in the American Tertiary, being known only by the four detached dental plates noticed by Wyman‘ and by Marsh.’ The peculiar teeth first described by Leidy from the Cretaceous of New Jersey under the name of Ischyrhiza, occur also in the Miocene of Maryland and North Carolina, if we may credit the statements of Cope’; and according to this author certain coalesced caudal vertebrae (“ hypural fans”) accompanying the Cretaceous teeth and occurring also in the Eocene of Maryland and South Carolina should be referred to this genus, which he claims is re- lated to the Hsocidae. It is much more likely, however, that the Cre- taceous fans belong to Protosphyraena or some similar form, and that the Tertiary fans, which all agree in having the terminal centrum at- tached, belong to one or more species of Sword-fishes. Genus XIPHIAS Linnaeus. Fragmentary remains of Sword-fishes have been met with from time to time in various Tertiary horizons, but in most cases are insufficient for accurate identification. Detached rostra and hypural fans of large size, both probably belonging to Xiphias or some related genus, are not uncommon in the Eocene of South Carolina. A number of such re- mains, including the types of X. robustus Leidy, are preserved in the Holmes Collection belonging to the American Museum of Natural His- tory in New York. Here also is to be seen the tooth of Ischyrhiza mira figured by Leidy in Holmes’ Post-Pleiocene Fossils of South Carolina (Plate XXV, Figs. 3, 4), which is the most perfect specimen of that 1 Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. viii, 1877, pp. 254-257, pl. xxxiv. 2 Thid., vol. i, 1849, p. 300, pl. xlii, figs. 10-13. 3 Proc. Amer. Philos. Soc., vol. xiv, 1875, p. 562. 4 Amer. Jour. Sci., ser. ii, vol. x, 1850, p. 284. 5 Proc. Amer. Assoc. Adv. Sci., 18th Meet., 1870, p. 228. 6 Vertebrata Cret. Form. West, Rept. U. 8. Geol. Sury. Territ., vol. 11,1875, p. 280. ail SYSTEMATIC PALEONTOLOGY form extant. The Tertiary caudal fans which have been theoretically associated with the teeth of Ischyrhiza by Cope and Clark are here con- sidered to belong to typical Sword-fishes. 'The following species is the only one known to occur in Maryland. XIPHIAS (?) RADIATA (Clark). Plate XIL, Fig. 8. Ischyrhiza (?) radiata Clark, 1895, Johns Hopkins Univ. Cire., vol. Xv, p. 4. Ischyrhiza (?) radiata Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 60, pl. vii, fig. 2a (? non figs. 2b, 2c). Description.—Terminal vertebral centrum deeply concave in front and circular in cross-section, its neural and haemal spines fused into a solid fan-shaped body; the anterior haemal spine less completely fused with the next following than are all the rest, and even separated from it near the point of attachment with the centrum by a small perforation passing completely through the fan. [Dentition and other parts of the skeleton unknown. | | ; This species is established on a unique fan-shaped body, the extreme height of which is 3.9 em.; but some of the South Carolina specimens exceed 10 cm. The latter also differ from the Maryland form in having the vertebral centrum transversely elongated instead of circular. The type is a hypural fan in the Museum of Johns Hopkins Uni- versity. Occurrence.—AQuia Formation. Clifton Beach. Collection —Johns Hopkins University. Genus PHYLLODUS Agassiz. The presence of this interesting genus in North America was first made known by Dr. Jeffries Wyman, who came into possession of two unique dental plates from the Eocene of Richmond, Virginia. Rather poorly executed woodcuts of both specimens are given by him, the more perfect one being compared with P. toliapicus Agassiz, and the other declared to be different from any described species. This paper of Wy- man’s seems to have escaped general notice, and was certainly over- looked by Marsh,* when in 1870 he claimed his P. elegans and P. curvi- 1Amer. Jour. Sci., ser. ii, vol. x, 1850, p. 234. 2Proc. Amer. Assoc. Adv. Sci., 18th Meet., 1870, p. 228. MARYLAND GEOLOGICAL SURVEY 113 dens, likewise founded on unique dental plates from the Eocene and Miocene respectively of New Jersey, to be the first indications of this genus in North America. Neither of the last two species have been figured, but it is probable from Marsh’s brief description that 2. elegans is a young example of P. toliapicus. Furthermore, it is practically cer- tain that neither of Wyman’s specimens are referable to P. toliapicus, but each is representative of a distinct species. Whether their horizon is Eocene or Miocene was not conclusively determined by Wyman, although the chances are in favor of attributing them to the former. Traces of this genus have not as yet been discovered in Maryland, but the following species deserves notice on account of its historical and scientific interest. PHYLLODUS HIPPARIONYX Na. sp. Phyllodus sp. aff. toliapieus Wyman, 1850, Amer. Jour. Sci., ser. li, vol. x, p. 234, woode. fig. 9a. Type—Detached dental plate; formerly in Museum of Comparative Zoology, Cambridge, Mass. ONOLEIDES: Plate XII, Figs. 4-6. Fish otolites, or “ ear-stones,” are found almost exclusively in the detached condition, this being due to the fact that they are held in place during life only by membranes, and hence readily fall out from the head and sink to the bottom while the decomposing body of the fish continues to float on the surface, a prey to all sorts of creatures, or is cast ashore by the waves. The circumstance of large numbers of fossil fish skeletons being found in close proximity to one another, but none of them having otolites preserved in situ, is cited as an argument against their having met their death suddenly or in shoals. The peculiar struc- ture and composition of otolites favor their preservation in the fossil state, hence it is not surprising that they should occur in considerable abundance and variety throughout the Tertiary and even older horizons. Rather is it the converse proposition which excites wonder; for when we consider the number of forms represented solely by ear-bones, it is diffi- cult to understand why not a vestige of other parts of the skeleton re- mains. s 114 SYSTEMATIC PALEONTOLOGY The otolites of Cyclostomes and cartilaginous fishes consist of irregu- lar and loosely united aggregations of lime carbonate; those of Teleos- tomes, on the other hand, are dense porcellanous bodies composed of microscopic crystals of calcite, excellently adapted for fossilization. The proportion of calcite frequently amounts to 98 per cent of the whole, and the organic matter rarely exceeds 4 per cent. Although extremely variable in form and size, nothing can be predicated from these char- acters as to the proportions of the complete fish. The sculpturing of the external surface, however, has been found fairly distinctive for cer- tain families; for instance, it is more or less tuberculose among the _GADIDAE, SCIAENIDAE, etc., and radially folded among the PERCIDAE and SPARIDAE. Otolites are secreted in a few definite regions of the auditory appa- ratus. A small one, termed by Koken the lJapillus, is formed in a por- tion of the labyrinth known as the “ vestibule” or utriculus; another (asteriscus of Koken) occurs in the posterior prolongation of the otolite- sac (sacculus), and the principal ear-stone in the center of the sac proper. The principal otolite (sagitta of Koken) occupies a constant position with reference to the investing sacculus, partaking of its shape and being attached to its inner wall; and accordingly it is capable of bemg precisely oriented, even when found in the detached fossil condition. That is to say, a dorsal and ventral, anterior and posterior, and inner and outer side are almost always to be recognized, as well as the side of the head to which it belongs. But on the other hand the configuration, and in the opinion of some excellent authorities, even the surface mark- ings of fish otolites are dependent on the variable form of the enclosing membranous sac, and are by no means constant within specific or even generic limits.’ ‘ 1« Hasse halt auch die Form der Otolithen fur unwichtig, als ein mit der Form des Sacculus sich anderndes Moment. ... Die Gestalt der Otolithen ist allerding’s in gewissen Grenzen variabel, in Zusammenhange mit den individuellen Schwankungen der Sacculus-Form, welcher sie sich anpasst. Auch ist das Wachsthum vorwiegend auf die aussere Seite angewiesen, welche freiim Sacculus liegt; .... dementsprechend ist das Wachsthum der dusseren Seite unregelmissiger, und gerade die auf die Sculptur derselben sich grundenden Merkmale . . . erwiesen sich 6fters als ungeeignet, weil sie sich durch Vergrosserung des Gehorsteines zu leicht verwischen.’’—E. Koken, Ueber Fisch-Otolithen etc. (Zeitschr. d. d. geol. Ges., vol. Xxxvi, 1884, p. 515). MARYLAND GEOLOGICAL SURVEY 115 Nevertheless, the structure and topography of these minute and ap- parently insignificant bodies have been investigated with great care, and a precise nomenclature established. For the depression extending from the anterior margin backward in a horizontal direction on the flat or concave inner side, Koken has proposed the designation of sulcus acusti- cus, and this he regards as furnishing the most important diagnostic characters. The sculpture of the inner and outer sides, and nature of the peripheral border, whether sharp or thickened, smooth, folded, den- ticulated or incised, and various minor characters of like nature are all taken into account in the attempt to identify detached specimens. Their size, too, is held to be an important distinguishing character. The most painstaking investigations on fossil otolites from both our own and European Tertiaries are those of Professor Koken,’ and refer- ence should be had to his writings by all interested in this subject. A summary of the earlier literature is given by him in the first paper cited below. If any are inclined to question the accuracy of his determina- tions of genera and species, the opportunity is certainly open for more extended comparisons with recent and fossil forms. Otolites occur rather frequently in the Eocene of Maryland, but only a few have been found in the Miocene at Plum Point. A few typical examples are shown in Plate XIJ, Figs. 4-6, but further than to say that they bear a general resemblance to those of the Gaprpa®, their identi- fication is not attempted here. Occurrence—N ANJEMOY FoRMATION. Port Tobacco, 24 miles above Popes Creek, Woodstock. Collection—Maryland Geological Survey. COPROLITES. Rolled cylindrical bodies of amorphous structure and very suggestive of fossil fish excrement are occasionally found at a few localities in the Eocene of Maryland and Virginia. The occurrence of coprolites of enor- mous size in the Miocene of Virginia has been known for a long time.” 1 Zoe. cit., pp. 500-565.—Neue Untersuchungen an tertiaren Fisch-Otolithen, ibid., vol. xl, 1888, pp. 274-305. 2 Wyman, Notice of Remains of Vertebrated Animals found at Richmond, Virginia, 925 Amer. Jour. Sci., ser. ii, vol. x, 1850, p. 235. 116 SYSTEMATIC PALEONTOLOGY ARTHROPODA. CLass @ RUSTACEA. Superorder MALACOSTRACA. Order DECAPODA. Family CANCROIDEA. Description—Claws belonging to an indeterminate genus of the Cancroidea are abundant in the bed underlying the indurated ledge at Upper Marlboro. All of the specimens are so fragmentary that no attempt is made to illustrate the forms. Collection.—Maryland Geological Survey. Superorder OSTRACODA. Family BAIRDIHDAE. Genus BYTHOCYPRIS Brady. BYTHOCYPRIS SUBAEQUATA 0D. Sp. Plate XVI, Figs. 1-4. Description.—Carapace about 1.0 mm. in length, elongate, subcyln- drical or, perhaps better, subreniform, the dorsal outline arcuate, the ventral shehtly hollowed, and the ends rounded and nearly equal, the posterior a trifle blunter than the anterior; end view nearly circular, dorsal and ventral views lanceolate, with the greatest thickness about the middle of the posterior half; left valve slightly overlapping the right along its ventral edge; surface smooth or very finely granulose. Inner side of valves with simple thin edges, and within these, except along the dorsal border, a thin bevelled plate, much the widest an- teriorly. There are numerous fossil and recent Ostracoda, mostly of otherwise widely diverging genera, that have a carapace similar to this, but none was found exactly matching it. MARYLAND GEOLOGICAL SURVEY alg Occurrence.—AQUIA FORMATION. Upper Marlboro. Collection.—Maryland Geological Survey. SYTHOCYPRIS PARILIS n. sp. Plate XVI, Figs. 5-8. Descriplion.—Carapace about 1.0 mm. long, and nearly or quite 0.5 mm. high; reniform, strongly arched dorsally, very slightly sinuate or straight in the ventral portion of the outline, and with the ends rounded and very nearly equal, the posterior outline however being usually a trifle oblique above, and the turn into the basal line slightly lower than at the front end; point of greatest thickness above the middle, the slope toward the ventral edge being flatter than elsewhere; edge view elongate, subelliptical, the anterior extremity more acute than the posterior, the latter being comparatively blunt. Left valve slightly overlapping the right both above and below, its ventral edge somewhat thickened in the middle and bordered along the anterior and posterior thirds of its extent by a sharply impressed, thin line. Surface generally appearing quite smooth, but under favorable circumstances very small scattered punctae may be observed. Interior of valves with the marginal plate well de- veloped and widest in front. This carapace is relatively higher, has a more arcuate back, and less acute anterior extremity (in edge view) than its associate B. subaequata. It is distinguished further by the dorsal overlap of the valves and in the ereater development of the internal marginal plate. Occurrence—Aguia Formation. Upper Marlboro. Collection—Maryland Geological Survey. Family CY THERELLIDAE. Genus CYTHERELLA Jones. CYTHERELLA MARLBOROENSIS N. sp. Plate XVI, Figs. 9-13. Description.—Carapace nearly regularly ovate, the height and length about as two is to three; 0.9 or 1.0 mm. in length; ventral portion of outline somewhat less convex than the dorsal. Right valve much larger than the left and projecting beyond it all around. Edge view obtusely anceolate, with both extremities ; thie sterior, t more so, anc ] late, with both extremities blunt, the posterior, the more and 118 SYSTEMATIC PALEONTOLOGY much thicker than the other; end view subovate. Valves compara- tively thin for this genus, the marginal groove of the right valve rela- tively narrow though sharply defined. Interior of right valve with two subovate smooth spaces, situated one in the anterior, the other in the posterior half, and around them concentric rows of small pustules. Sur- face smooth or minutely punctate. . No known Tertiary species agrees very closely with this. The well- known C. compressa (Miinster), has a similar edge view, as have also several other species, but otherwise, the form of its carapace, especially the ventral portion of the outline, is quite different. The Cretaceous C’. ovata is probably a closer relative but differs obviously im its edge and end views. Occurrence—AQquia Formation. Upper Marlboro. Collection —Maryland Geological Survey. CYTHERELLA SUBMARGINATA N.. sp. Plate XVI, Figs. 14, 15. Description.—Carapace about 1.0 mm. in length, somewhat oblong, rounded at the ends, the posterior end a little wider and its margin more oblique above and merging more gradually into the very slightly arcuate dorsal outline than the anterior; ventral margin straight, edge view subeuneiform, end view subovate. Valves compressed convex, thickest posteriorly, with an obscurely defined broad depression near the midlength and mostly above the center of the valves. A narrow but distinct rim borders the two ends. Surface smooth. Of this species only the single valve figured has been seen. Com- pared with described species it was found to agree rather well with C. londinensis Jones a Lower Eocene species from London, Eng., but after a closer examination it was decided that it could not be justly referred to that species. As described and figured C. londinensis must have quite a different appearance in edge views, due to the more uniform convexity of its valves. The central depression and marginal rims as well as its different outline, will serve to distinguish C. submarginata at once from C. marlboroensis with which it is associated. Occurrence—AQuta Formation. Upper Marlboro. Collection.—Maryland Geological Survey. MARYLAND GEOLOGICAL SURVEY 119 Family CY THERIDAE. Genus CYTHERE Miller, CYTHERE MARYLANDICA Nn. sp. Plate XVI, Figs. 16-18. Description.—Carapace about 1.0 mm. in length and 0.55 mm. in height and thickness, subovate in outline; hinge straight, half the en- tire length of carapace, ventral outline broadly arcuate; anterior end obliquely rounded, most prominent in the lower half and much wider than the posterior end; the latter is neatly rounded below, obtusely angu- lar above the middle, then straight or slightly sinuate to the subangular extremity of the hinge line. Valves unequal, the left overlapping the right, very convex and swollen in the middle and thickest near the ventral edge. The swollen region of the valves is of subtriangular shape and sharply defined where it rises from the relatively small, compressed, terminal remnants of the surface. Of these remnants the posterior is more depressed (it may appear like a flattened border) and narrower than the anterior one, and both are marked with shallow pits arranged in rather obscure concentric series. The surface of the swollen region is more distinctly pitted, with the pits arranged in the lower half between more or less sharp longitudinal curved riblets and much less regularly in the upper half. Sometimes the swelling is terminated below by one or two ribs more prominent and stronger than the rest. Edge view subovate, with the ends produced; end view subtriangular with the lat- eral lines rather strongly convex. Hingement consists as usual in Cythere of large lateral teeth and connecting bar. This seems to be a well-marked species with not very close relations to C. trigonula Jones and C. triangularis (Reuss) Jones. From both it differs in outline, the former, varying further in, having also a finer surface punctation, a much more triangular end view, and relatively very slightly compressed ends causing the edge view to be equally dif- ferent. C. triangularis agrees better in end and edge views but its sur- oe face differs decidedly, being “smooth, shining, and beset with scattered setae.” Another of the species described by Jones in his Monograph of the Tertiary Entomostraca of England, especially since he mentions that he has a scarcely distinguishable variety of it from the middle Ter- 120 SYSTEMATIC PALEONTOLOGY tiary of Maryland, may be compared with OC. marylandica. This 1s Cythere punctata (Miinster). Judging from illustrations alone the pres- ent species must be quite distinct and so obviously that it seems highly improbable that the American variety of Miinster’s species mentioned by Jones, is the same as the one above described. Occurrence—AQuia Formation. Upper Marlboro, Brooks Estate near Seat Pleasant. Collection.—Maryland Geological Survey. Genus CYTHEREIS Jones. CYTHEREIS BASSLERI 0. sp. Plate XVI, Figs. 19-21. Description—Carapace oblong, length 0.80 to 0.85 mm., widest and rounded anteriorly; the posterior edge more or less angular in the mid- dle, straight or slightly sinuate above to the angular extremity of the hinge, and with two or three spines projecting from the shghtly convex, lower half; edges with a thickened rounded rim, becoming obsolete near the center of the flattened ventral region; hinge line straight except at the antero-cardinal angle which is thickened and prominent; ventral outline slightly simuate. Valves equal, with a rounded sub-central node, sometimes obscured by a network of small ridges, and a sharp ventral ridge rising gradually from its inception at the antero-ventral angle and ceasing abruptly at a point about one-fourth of the length of the valve from its posterior extremity. A less prominent ridge runs from the high end of the ventral ridge in a slightly oblique direction to the post- cardinal angle and then turns forward. ‘The whole surface is covered with rather large pits arranged in more or less irregular curved series, the space between the rows, especially over the central portion of the valves being raised into thin and sometimes coalescing ridges. This species presents more or less close affinities with no less than six of the species of Cythere figured by Bosquet in his excellent Mono- graph of the Ostracoda of the Tertiary deposits of France.” These are CO. hebertiana Bosq., C. thierensiana Bosq., C. deshayesiana Bosq., C. 1Dese. des Entomostrace’s Fossiles des Terrains Tertiaires de la France et de la Belgique. Mem. Couron. Acad. Belg., Tome xxiy, 1851. MARYLAND GEOLOGICAL SURVEY 121 angusticostala Bosq., C. macropora Bosq. and C. edwardsi (Roemer), all Kocene species except the last, which is a widely distributed Miocene fossil. Despite the often striking similarities presented, not one of the European species mentioned agrees closely enough in all respects to justify a reference of the Maryland form to it. Cythereis basslert, which IT name in honor of my able and indefatigable assistant, Mr. R. 8S. Bassler, seems to be a common fossil at Upper Marl- boro, Considering that the specimens studied present considerable variation in surface sculpture, it is possible that they represent more than a single specific type. I have also a specimen from the Cretaceous at Vincentown, N. J., which can scarcely be distinguished from the Upper Marlboro specimen figured. Occurrence—AQutia Formation. Upper Marlboro. Collection Maryland Geological Survey. Genus CYTHERIDEA Bosquet. CYTHERIDEA PERARCUATA N. sp. Plate XVI, Fig. 22, 23. Description.—Carapace 1.1 mm. long, 0.6 mm. high, strongly and, ex- cepting the acuminate posterior extremity, rather uniformly convex, obliquely acute-ovate in outline; ventral edge straight to the acute pos- terior extremity, the sharpness of which is emphasized by a small spine; anterior outline wide and regularly rounded, and armed with five or six spines; dorsal side strongly arcuate, the curve straightening some- what as it nears the posterior end. Central portion of surface, over a space corresponding in shape with the outline of the valves, marked with eleven or twelve approximately vertical furrows, each including a row of small punctures. Beyond this space the surface is smooth, ex- cepting toward the posterior end where an obscurely wrinkled appearance may be observed. Ventral edge of right valve with a narrow bevel in- ward. Hinge as required by the genus, consisting of a series of small denticles at each end of the hinge in right valve and corresponding sockets in the left valve. Edge view broadly lanceolate, thickest near the middle length and slightly more attenuate behind than in front; end view subcireular. 122 SYSTEMATIC PALEONTOLOGY At first it was believed that this form might be regarded as a variety of Cytheridea miilleri (Mimster), a common and widely distributed European Tertiary and Recent species. However a more careful com- parison brought out so many differences that it seemed best to rank them as distinct species. This conclusion was confirmed by finding almost unquestionable C. miuilleri associated with C. perarcuata at Woodstock, while C. intermedia (Reuss) which Jones considers a elose variety of C. miilleri, was found rather abundantly in association with specimens agreeing closely with Jones’ C. debilis, at Upper Marlboro. C. perarcu- ata differs from all of these forms in the restricted extent of its surface markings, in wanting a mesial furrow, in its relatively greater height and more strongly arcuate dorsal outline. Its edge view furthermore is decidedly different, the central portion being thicker, while the ends, the posterior especially, are thinner. Occurrence.—NANJEMOY ForMATION. Woodstock. Aguria FoRMA- TION. Potomac Creek. Collection.— Maryland Geological Survey. MOLLUSCA. Crass CEPHALOPODA. Subclass TETRABRANCHIATA. Order NAUTILOIDEA. Suborder ORTHOCHAENITES. Family CLYDONAUTILIDAE. Genus HERCOGLOSSA Conrad. HERCOGLOSSA TUOMEYI Nn. sp. Plates XVII-XIX. Nautilus sp. Tuomey, 1842, Amer. Jour. Sci., vol. xliii, p. 187. Nautilus sp. Clark, 1895, Johns Hopkins Uniy. Cire., vol. xv, p. 4. Nautilus sp. Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 63, pl. ix, fig. 1. Description.—Shell large; aperture wide, narrowing rapidly, without curving to a narrow and sharply rounded periphery; ventral saddles of ~~ MARYLAND GEOLOGICAL SURVEY 125 moderate size; lateral lobes regularly but moderately rounded; lateral saddles narrower and sharper than the other saddles; umbilici not small; shell thick (2-8 mm.), marked by fine, distinct, closely-set lines of growth, which sweep sharply back on the periphery. This species is distinguished from H. (2nelimatoceras) ulrichi by its much less prominent ventral saddles, and by its less uniformly rounded transverse section, the sides being almost without curvature down almost to the very periphery. The nautiloid shell which Tuomey roughly described without naming was from the James river and from a horizon exactly corresponding to our Popes Creek occurrence. There is little doubt that it was this species. Diameter (restored) of coil of largest specimen about 400 mm. Occurrence—NANJEMOY Formation. Popes Creek (abundant). Aquta Formation. Clifton Beach (fragments rare). Collections—Maryland Geological Survey, Johns Hopkins University. Gas GASTROPODA. Order OPISTHOBRANCHIATA. Suborder TECTIBRANCHIATA. Family ACTAEONIDAE. Genus TORNATELLAEA Conrad. TORNATELLAEA BELLA Conrad. Plate XX, Figs. 1, 1a, 2. Tornatellaea bella Conrad, 1860, Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. iv, p. 294, pl. xlvii, fig. 23. Tornatella bella Clark, 1895, Johns Hopkins Uniy. Cire., vol. xv, p. 4. Tornatella bella Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 63. Description.—* Ovate, spire conical; revolving lines numerous, im- pressed, punctate striate.” Conrad, 1860. Shell solid, ovate in profile, six-whorled; surface with uniform, punc- tate, spiral grooves, crossed only by lines of growth and regularly un- 124 SYSTEMATIC PALEONTOLOGY dulating in width; spire short, conical, acuminate; whorls slightly con- vex; body whorl more than half the length of the shell, moderately convex; suture distinct; outer lip sometimes crenulate; columella with two pronounced oblique plicae. Length, 15 mm.; width, 8 mm. Occurrence. —N ANJEMOY Formation. West of Port Tobacco. Wood- stock, 1 mile southeast of Piscataway. AquraA Formation. Aquia Creek, Potomac Creek, 1 mile northeast of Piscataway, Upper Marlboro. Collections —Maryland Geological Survey, Philadelphia Academy of Natural Sciences, U. S. National Museum. Family RINGICULIDAE. Genus RINGICULA Deshayes. RINGICULA DALLI Clark. Plate XX, Figs. 3, 3a. Ringicula dalli Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 4. Ringicula dalli Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 64, pl. ix, figs. 3a, #b. Ringicula dalli Aldrich, 1897, Bull. Amer. Pal. No. 8, p. 8, pl. ii, fig. 6. Description —* Shell small, five-whorled; surface of last four whorls strongly striate spirally; spire elevated, acuminate; body whorl much inflated; outer lip much thickened and crenulate within; columella with thick callous and with two strong plaits.” Clark, 1896. Length, 3 mm.; width, 2 mm. Occurrence—N ANJEMOY Formation. Woodstock. Collection Maryland Geological Survey. Family SCAPHANDRIDAE. Genus CYLICHNA Loven. CYLICHNA VENUSTA Clark. Plate XX, Figs. 4, 4a. Cylichna venusta Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 4. Cylichna venustu Clark, 1896, Bull. 141, U.S. Geol. Survey, p. 64, pl. ix, figs. 2a, 20. Description Shell small, elongate-ovate, rather globose; surface spirally striate; spire depressed; columella with small obscure plait.” Clark, 1896. omy be i MARYLAND GEOLOGICAL SURVEY 125 The spire is usually perforate, and the revolving lines alternate and punctate. It most closely resembles C. aldrichi Langdon, from which it is distinguished by being proportionally longer, less cylindrical in out- line, and with the spire less strongly perforate. x Length, 7 mm.; width, 3.5 mm. Occurrence.—N ANJEMOY ForMATION. West of Port Tobacco, Head of Nanjemoy Creek, Woodstock. Aguta Formation. 1 mile southeast of Mason Springs, Potomac Creek, 2 miles below Potomac Creek, 1 mile northeast of Piscataway, Clifton Beach. Collections. Johns Hopkins University, Maryland Geological Survey. Superfamily TOXOGLOSSA. Family PLEUROTOMIDAE. Genus PLEUROTOMA Lamarck. PLEUROTOMA HARRIS Clark. Plate XX, Figs. 5, 5a, 6. Pleurotoma harrisi Clark, 1895, Johns Hopkins Univ. Circ., vol. xv, p. 4. Pleurotoma harrisi Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 64, pl. ix, figs. 4a, 4b. Description—* Shell of moderate size, elongate, five or six whorled; surface with distinct, revolving lines of varying size, crossed by trans- verse ridges; aperture narrow, with long straight canal.” Clark, 1896. The lower half of the whorl is strongly convex and is strongly orna- mented with revolving lines, alternating in size, and is crossed on the shoulder by oblique nodular ridges. The upper half of the whorl is flat, with very faint revolving lines, except one or two strong ones about the middle of the flat zone. The ‘aperture narrows rapidly toward the base, the body whorl partaking of the constriction. ‘The canal is very long, straight, and narrow. Length, 30 mm.; width, 8 mm. Occurrence—AQuia ForRMATION. Potomac Creek, 2 miles below Po- tomac Creek, 1 mile southeast of Mason Springs. Collection Maryland Geological Survey. 126 SYSTEMATIC PALEONTOLOGY PLEUROTOMA POTOMACENSIS N. sp. Plate XX, Figs. 7, 7a. Description—Shell attenuate, with spire and beak of equal length; aperture narrow; beak long and straight; whorls seven, with four more in the nucleus; few large, raised, revolving lines on and below the shoul- ders; numerous fine, proximate lines between these, and covering the entire whorl; two prominent, raised, revolving lines* below the suture, the lower more prominent; shoulder with acute nodes, carinated by one or two of the major revolving lines; lines of growth faint. Some varieties of P. nasuta Whitfield are very similar to this species. it is intermediate between that species and P. harrisi Clark. Length, 31 mm.; width, 8 mm. . Occurrence—AQuia ForMATION. 1 mile northeast of Piscataway, 2 miles below Potomac Creek. Collection—Maryland Geological Survey. PLEUROTOMA DUCATELI 0. sp. Plate XX, Fig. 8. Description.—Surface smooth, save for faint, impressed, revolving lines which become stronger just below the suture, and very strong on the beak; suture very distinct; columella straight, striated spirally; lines of growth faint, with broad sinus below the suture. Length, 10 mm.; width, 4 mm. Occurrence—AQuIaA ForMATION. 1 mile southeast of Mason Springs. Collection.—Maryland Geological Survey. PLEUROTOMA TYSONI N. sp. Jedbeire OS ie Oe Descriplion.—Shell eight-whorled; body whorl about half the length of shell; mouth contracting but slightly toward beak; body whorl with sixteen, oblique, longitudinal ribs, strongly nodular where crossed by the large, elevated, revolving lines; eight strong, revolving lines on the body whorl below the shoulder, and numerous fainter ones below, on the beak. All the whorls are concave above the shoulder, and unsculptured, save for lines of growth and for a strong, raised, nodular, subsutural MARYLAND GEOLOGICAL SURVEY 12 line. Whorls of the spire with four nodular revolving lines below the shoulder. Length, 12 mm.; width, 4 mm. Occurrence-—AQUuIA FORMATION. 1 mile southeast of Mason Springs. Collection.—Maryland Geological Survey. Subgenus HEMIPLEUROTOMA Cossmann. PLEUROTOMA (HEMIPLEUROTOMA) CHILDRENI Lea. Plate XX, Figs. 10, 11. Pleurotoma childreni Lea, 1835, Contrib. to Geol., p. 137, pl. iv, fig. 132. Pleurotoma denticula var Harris, 1899, Bull. Amer. Bale NO ie pacientes, 21, 22. Description.—* Shell fusiform, turrited, transversely striate, granu- late on the larger part of the whorl; substance of the shell rather thick; spire elevated, obtuse at apex; whorls about nine, subcanaliculate above; mouth long and narrow, one-third the length of the shell.” Lea, 1833. Our specimens vary considerably in the smaller details of sculpture, but all seem to fall within the limits of variation of the Alabama form. Whether they are the same as the French species P. denticula Bast. to which Professor Harris assigns the Alabama form is a question that cannot be settled here. They agree with it well enough to fall into the subgenus Hemipleurotoma of which P. denticula is the type. Length, 12 mm.; width, 3.5 mm. Occurrence—AQuIA FORMATION. 1 mile southeast of Mason Springs, 2 miles below Potomac Creek. Collection.—Maryland Geological Survey. PLEUROTOMA PISCATAVENSIS Nn. sp. Plate XX, Fig. 12. DescriptionShell fusiform, seven-whorled, carinated; lines of growth distinct; revolving lines absent above the shoulder, one to three in num- ber below the shoulder; beak marked only by lines of growth; nucleus three-whorled, smooth; following whorls of the spire with oblique pli- cae, extending from suture to suture; body whorl with about ten acute nodes, confined to the suture. 128 SYSTEMATIC PALEONTOLOGY Length, 11 mm.; width, 4 mm. Occurrence.—AQuis Formation. 1 mile northeast of Piscataway. Collection Maryland Geological Survey. Genus MANGILIA ‘Risso. Subgenus PLEUROTOMELLA Venill. MANGILIA (PLEUROTOMELLA) BELLISTRIATA Clark. Plate XX, Figs. 13, 13a. gs. Mangilia (Pleurotomella) bellistriata Clark, 1895, Johns Hopkins Univ. Circ., vol. xv, p. 4. Mangilia (Pleurotomella) bellistriata Clark, 1896, Bull. 141, U.S. Geol. Survey, p. 65, pl. ix, fig. 5. Description —* Shell small, subfusiform, with a rather short, pointed spire, and about five whorls; body whorl large, somewhat inflated; earlier whorls nearly flat; surface sculptured with numerous, alternating, larger and smaller spiral threads, crossed by fine, wavy lines, and by irregu- larly spaced, oblique ribs, about twenty in number on the body whorl; ribs strongest at the shoulder, gradually disappearing both posteriorly and anteriorly; behind the shoulder somewhat excavated; aperture nar- tow.” Clark, 1896. : There is a distinct fold on the columella, and the lines of growth are very slightly curved. Length, 27 mm. (restored); width, 13 mm. Occurrence—N sNJEMOY ForMATION. Popes Creek. Aguia FoRMa- TION. Potomac Creek. Collections—Johns Hopkins University, Philadelphia Academy of Natural Sciences. Family CANCELLARIDAE. Genus CANCELLARIA Lamarck. CANCELLARIA GRACILOIDES Aldrich, var. Plate XXL, Fig. 1. Cancellaria graciloides Aldrich, 1898, The Nautilus, vol. xi, p. 98. : Cancellaria graciloides Harris, 1899, Bull. Amer. Pal., No. 11, pp. 28, 29, pl. iii, figs. 10, 11. Description.—* Shell broadly fusiform, spire elevated, whorls 6-7, rounded, slightly shouldered, cancellated, first three smooth, on the MARYLAND GEOLOGICAL SURVEY 129 others the revolving lines are numerous, strongly defined; lines of growth smaller and much finer than the revolving lines, suture deeply im- pressed, outer lip expanded, strongly nodular within, columella with three folds, aperture pointed and canaliculate at base.” Aldrich, 1898. This abundant and variable form approaches too near to some va- rieties of C. graciloides to be safely separated from it. Length, 13 mm.; width, 8 mm. Occurrence.—AQvuIA ForMATION. 1 mile southeast of Mason Springs. Collection Maryland Geological Survey. CANCELLARIA sp. Plate XXI, Fig. 2. Several specimens of Cancellaria were found that are so imperfect and immature, that it is unsafe to describe them or even to refer them to any known species, yet they are very different from our other Maryland species. The figured specimen represents a form from the locality two miles below Potomac Creek which also doubtfully occurs at Potomac Creek, and which distantly recalls C. parva Lea.” When the adult is found it will probably be recognized as a new species. Another form from Potomac Creek may be C. ulmula Harris* or a variety. This is so imperfect that it does not seem desirable to figure it. Occurrence—AQuIA FORMATION. 2 miles below Potomac Creek, Po- tomac Creek. Collection Maryland Geological Survey. Subgenus NARONA H. and A. Adams. CANCELLARIA (NARONA) POTOMACENSIS ND. sp. Plate XXI, Figs, 3, 3a. Description Shell elongate; mouth more than half the length of the shell; spire short; whorls marked with distinct, raised, flat-topped, re- volving ridges, with interspaces twice as broad; body whorl with twenty of these ridges, whorls of the spire with six. Lines of growth and 1Contrib. Geol., p. 42, pl. v, fig. 141. 2Proc. Acad. Nat. Sci. Phila., vol. xlvii, 1895, p. 66, pl. vi, fig. 6. 9 130 SYSTEMATIC PALEONTOLOGY several variable, usually obscure, longitudinal undulations cross the revolving ribs, granulating them and often reticulating the surface. Labium expanded, grooved and cancellated. Labium with two, distinct, oblique folds and numerous striae, continuations of the external revolv- ing lines. Canal short, recurved. Length, 17 mm.; width, 8 mm. Occurrence.—AQuia ForMATION. 1 mile southeast of Mason Springs. Collection.—Maryland Geological Survey. Superfamily RACHIGLOSSA. Family OLIVIDAE. Genus OLIVULA Harris. OLIVULA sp. A single specimen was found which gives little doubt of its generic character. It is probably distinct from O. staminea (Conrad). In the imperfect condition of the specimen it is impossible to assign it to any species, new or old, and a figure would show no determining characters. Length, 20 mm.; width, 6 mm. Occurrence—NANJEMOY FoRMATION. Popes Creek. Collection. Maryland Geological Survey. Family VOLUTIDAE. Genus VOLUTILITHES Swainson. VOLUTILITHES PETROSUS (Conrad). Plate XXI, Figs. 4, 5, 5a. 7oluta petrosa Conrad, 1833, Fossil Shells of the Tertiary, No. 3 [1st Edit.], p. 29. Voluta petrosa Conrad, 1835, Fossil Shells of the Tertiary, No. 3 [2nd Edit.], p. 41, pl. xvi, fig. 2. Athleta twomeyi Conrad, 1853, Proc. Acad. Nat. Sci. Phila., vol. vi, p. 449. Volutilithes (Athleta) tuomeyi Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 4. Volutilithes (Athleta) twomeyi Clark, 1896, Bull. 141, U. 8S. Geol. Survey, p. 65, pl. x, figs. la, 1b. Description.—< Shell subglabrous; body whorl marked with from eight to ten longitudinal folds, terminating on the shoulder in compressed MARYLAND GEOLOGICAL SURVEY 131 subacute tubercles, which are also distinct on the spire: transversely striated at base: two folds on the columella.” Conrad, 1833. The Maryland specimens are principally of the tuomeyi type, but the normal form occurs with it at most localities. Length, 38 mm.; width, 25 mm. Oceurrence.—N aNJEMOY Formation. Woodstock, Popes Creek, West of Port Tobacco. AQqura Formation. Potomae Creek, 2 miles below Potomac Creek, 1 mile northeast of Piscataway, 1 mile southeast of Mason Springs, Aquia Creek. Collections—Maryland Geological Survey, Johns Hopkins University, Philadelphia Academy of Natural Sciences, U. 8S. National Museum. VOLUTILITHES sp. Plate XXI, Figs. 6, 6a. Volutilithes sp. Clark, 1895, Johns Hopkins Univ. Circ., vol. xv, p. 4. Volutilithes sp. Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 65, pl. x, figs. 2a, 26. A fine cast of a large species of Volutilithes was obtained from the in- durated ledge, Zone 3, at the Aquia Creek bluffs, and a very imperfect specimen from Potomac Creek. It is unlike any of the species of Volu- tilithes hitherto described, but from the fact that the shell substance is almost lacking no attempt will be made to give a full description. It has a somewhat compressed form, due to pressure. The shell substance is extremely thin, and the surface is marked only by lines of growth. The tubercles are obtuse and distant, and the spire small. Length, 75 mm.; width, 53 mm. Occurrence—Aquia Formation. Aquia Creek, Potomac Creek. Collections—Maryland Geological Survey, Johns Hopkins University. Genus CARICELLA Conrad. CARICELLA PYRULOIDES (?) (Conrad). Plate XXI, Figs. 7, 8. Turbinella pyruloides Conrad, 1833, Fossil Shells of the Tertiary, No. 2, p. 24, pl. x, fig. 1. (?) Caricella sp. Clark, 1895, Johns Hopkins Univ. Circ., vol."xv, p. 4. (?) Caricella sp. Clark, 1896, Bull. 141, U. S. Geol. Survey, p. 66, pl. xi, fig. 1. 132 SYSTEMATIC PALEONTOLOGY Description.—* Pyriform, ventricose, smooth; with obscure spiral striae on the inferior half of the body whorl; spire very short; apex slightly mammillated; columella with 4 distant oblique plaits.” Con- rad, 1833. . The specimens which are referred to this species consist of the cast and the broken shell which are figured, and a still more imperfect cast. It is not certain that they belong to the same species, or that any of them belong to the species to which they are here referred. If they do not belong here they probably represent one or more undescribed species. Length, 55 mm.; width, 22 mm. Occurrence—AQuia Formation. Potomac Creek, Aquia Creek, Liv- erpool Point. Collections—Maryland Geological Survey, Johns Hopkins University. Genus MITRA Lamarck. MITRA MARYLANDICA Clark. Plate XXI, Figs. 9, 9a. Mitra marylandica Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 4. Mitra marylandica Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 66, pl. xi, figs. 4a, 4b (not 3). Description.—* Shell small, rather thick, with six (?) whorls; surface with numerous, thickly-set spiral threads, crossed by fine wavy lines, giving a finely reticulated appearance; spine moderately high; suture distinct, appressed; shoulder not prominent; aperture elongated; col- umella nearly straight, with three plaits.” Clark, 1896. The essential character which distinguishes this species from the fol- lowing is the lack of ribbing. Length, 21 mm.; width, 7 mm. Occurrence—AQuia Formation. Pomonkey Neck. Collection.—U. 8. National Museum. MITRA POMONKENSIS Na. sp. Plate XXI, Figs. 10, 10a. Mitra sp. Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 4. Mitra sp. Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 66, pl. xi, figs. 8a, 3b. Description.—Shell larger than M. marylandica; whorls strongly con- vex, and with a somewhat angulated shoulder slightly above the middle; MARYLAND GEOLOGICAL SURVEY 133 sculptured by numerous, approximate, impressed, revolving lines, and variable longitudinal ribs, which stop at the shoulder, leaving a subsu- tural constriction above it. The best specimens of this species are in the Philadelphia Academy and are from Potomac Creek. The type in the U. S. National Museum is now labelled “‘ Near Mouth of Potomac Or., G. D. Harris,” but it was supposed when des- eribed to have come from Pomonkey Neck. Length, 25 mm.; width, 9 mm. The largest specimen has width of 12 mm. Occurrence—AQuia ForMATION. Pomonkey Neck, 2 miles below Po- tomac Creek, Potomac Creek, 1 mile northeast of Piscataway. Collections Maryland Geological Survey, U. 8. National Museum, Philadelphia Academy of Natural Sciences. MITRA POTOMACENSIS 0. sp. Plate XXI, Fig. 11. Description.—Shell small; whorls but slightly convex, and not con- stricted below the suture; revolving lines fine, distinct; ribs reaching from suture to suture, and often extending in one continuous line from whorl to whorl; ribs usually sharp and narrow. Length, 12 mm.; width, 3.5 mm. Occurrence—NaNsEmMoy Formation. Woodstock, Popes Creek. Aquta Formation. 1 mile northeast of Piscataway. Collection—Maryland Geological Survey. Family FUSIDAE. Genus LATIRUS Montfort. LATIRUS MARYLANDICUS N. sp. Plate XXI, Figs. 12, 12a. Description—Shell subfusiform, five or more whorled; body whorl with fifteen, blunt, irregular, longitudinal folds, and a number of re- volving ridges, very prominent on the shoulder and gradually dying out toward the beak; entire shell covered by fine, closely-set, raised, revolv- 134 - SYSTEMATIC PALEONTOLOGY ing threads, which over-ride both the longitudinal and the revolving folds, the threads showing a tendency to alternate in size; whorls of spire with two, very distinct, revolving folds; major intersecting sets of sculpture giving a reticulate appearance; folds strongly nodular at the intersections; mouth narrow; columella with two, strong, oblique folds; canal long and straight. Length, 26 mm.; width, 11 mm. ‘ Occurrence—AQuia ForMATION. 2 miles below Potomac Creek. Collection.—Maryland Geological Survey. Genus FUSUS (?) Lamarck. The following species are referred to the genus Fusus without any claim that their biological affinities are with that genus as now restricted. They belong to that large group of fossils, of approximately fusoid form, but indeterminate generic relationships. Fusus (?) suBTENuIS Heilprin. Plate XXII, Figs. 1, 2. Fusus subtenuis Heilprin, 1880, Proc. Acad. Nat. Sci. Phila., vol. xxxy, p. 371, pl. xx, fig. 4. Description“ Shell fusiform, of about seven subangular volutions; whorls ornamented with somewhat obscure longitudinal folds, about twelve on the body whorl, which are cut by several prominent revolving ridges commencing at the shoulder angulation; shoulder of the whorls more or less smooth, with an obscure median revolving line, and a prominent subsutural one; aperture about the length of the spire, or slightly exceeding it, the canal gently curved, moderately contracted, and somewhat expanding at the extremity; outer lip thin, and showing internally the external ornamentation; base with numerous revolving lines, which alternate in coarseness.” Heilprin, 1880. Very characteristic specimens of this species occur at the locality noted below. . Length, 35 mm. (restored); width, 18 mm. Occurrence—AQuIA FoRMATION. 2 miles below Potomac Creek. Collection.—Maryland Geological Survey. MARYLAND GEOLOGICAL SURVEY ] ee) or Fusus (?) INTERSTRIATUS Heilprin. Plate XXII, Figs. 4, 4a. Fusus interstriatus Heilprin, 1880, Proc. Acad, Nat. Sci, Phila., vol. xxxy, pl. xx, fig. 11. Description.—* Shell fusiform, slender, composed of about. ten convex volutions, the first three of which are smooth; whorls ornamented with both longitudinal plications and revolving lines, the last of which (about eight in the upper whorls), alternate with finer intermediate striae; the longitudinal plications distinct on the earlier whorls, but becoming much less so on the body whorls, and the one preceding; aperture about the length of the spire; the canal somewhat tortuous; outer lip thin, den- tate within.” Heilprin, 1880. The Maryland form differs from that from the Gulf states in that its ribs are alternate, while in the latter they are doubly alternate or with three smaller ones between each pair. The longitudinal plications may be either present or partly absent as on the Gulf form. Length, 16 mm.; width, 6 mm. Occurrence.—NANJEMOY ForRMATION. Woodstock. Aguta Forma- TION. 1 mile northeast of Piscataway, Aquia Creek. Collection—Maryland Geological Survey. Family MURICIDEA. Genus TROPHON Montfort. TROPHON SUBLEVIS Harris. Plate XXII, Fig. 3. Trophon sublevis Harris, 1899, Bull. Amer. Pal., No. 11, p. 61, pl. viii, figs. 1, 19. Description.—* Size and general form as indicated by the figure; whorls seven, embryonic three smooth, spire and body whorl smooth, polished, but with nine sharp-edged costae on each whorl, becoming somewhat pointed on the shoulder; faint undulations indicating indis- tinct, distant spirals between the ribs; outer lp thickened, with five crenulations within, the upper the stronger; no umbilicus.” Harris, USES). 136 SYSTEMATIC PALEONTOLOGY A single fragment was found which may safely be assumed to repre- sent this species. Length, 13 mm. (restored); width, 5 mm. Occurrence.—AQUIA FORMATION. 1 mile northeast of Piscataway. Collection.—Maryland Geological Survey. Family BUCCINIDAE. Genus STREPSIDURA Swainson. STREPSIDURA SUBSCALARINA Heilprin. Plate XXII, Figs. 5, 6, 7, 8, 8a. . Fusus (Strepsidura) subscalarinus Heilprin, 1880, Proc. Acad. Nat. Sci. Phila., vol. XXXV, p. 372, pl. xx, fig. 8. Fusus (Strepsidura) perlatus Clark, 1895, Johns Hopkins Univ. Circ., vol. xv, p. 4. Fusus (Strepsidura) perlatus Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 67. Description.—* Shell somewhat bucciniform, whorls about eight, sub- angular, the first three or four smooth, the remainder ornamented with both longitudinal costae and revolving striae, the latter showing a ten- dency to alternate in size; the costae are arcuate, not in a regularly con- _ tinuous series, those of the body whorl extending considerably below the middle of the whorl; aperture about the length of spire, the canal somewhat reflected; columella covered with a callous deposit, consider- ably twisted; outer lip dentate within.” MHeilprin, 1880. Our specimens show a marked tendency to variation both in shape and sculpture, as the figures show, but none of the forms seem to be sufficiently definite to warrant the separation of another species. Occurrence—NANJEMOY ForMATION. Popes Creek, Woodstock. Aquia Formation. Liverpool Point, Potomac Creek, 2 miles below Potomac Creek, Upper Marlboro. Collections —Maryland Geological Survey, Johns Hopkins University, Philadelphia Academy of Natural Sciences. Genus MELONGENA Schumacher. MELONGENA (?) POTOMACENSIS 0. sp. Plate XXII, Fig. 9. Description.—Shell fusiform, showing five angulated whorls (the api- cal whorls and portion of the body whorl wanting); with about twelve MARYLAND GEOLOGICAL SURVEY 137 longitudinal costae, which do not extend above the shoulder; ribs crossed by numerous more or less alternating ridges, of which two on the body whorl, about half-way between the shoulder and the anterior end, are noticeably larger than the others; finer lines of growth cross the ridges forming a somewhat rugose sculpture; above the shoulder smooth with a few small revolving raised lines and still smaller arcu- ated lines of growth. The figured specimen is the only one known. It resembles very closely Melongena subcarinata of the Paris Basin Eocene. There is also a resemblance to Papillina staminea var. Harris’ from Claiborne, Ala- bama. Length, 34 mm.; width, 18 mm. Occurrence.—AQuia FORMATION. Potomac Creek. Collection.—Philadelphia Academy of Natural Sciences (No. 6880 of the Lea Memorial Collection). Genus TUDICLA Bolten. TUDICLA MARYLANDICA DN. sp. Plate XI, Bigs. 45) la; Ip. Description.—Spire flat, concealed except on top by the body whorl which is large, much expanded above, but rapidly contracting below; surface marked by lines of growth, and fine, revolving wrinkles which become strong toward the beak; periphery of body whorl with spines of moderate size; beaks long, narrow, reflexed; columella twisted obtusely. This species differs from P. pyrula Ald. in not having the elevated spire shown in Harris’ figure of a Midwayan specimen, and also in not having as elevated a spire, as ovate a mouth, nor being as strongly spinose as the Chickasawan specimens. Length, 70 mm.; width, 50 x 35 mm. Occurrence.—AQuia FORMATION. 2 miles below Potomac Creek. Collection —Maryland Geological Survey. 1Proc. Acad. Nat. Sci. Phila., vol. xlviii, 1896, p. 474, pl. xx, fig. 2. 2Bull. Amer. Pal., vol. iv, pl. xix, fig. 2. 138 SYSTEMATIC PALEONTOLOGY TUDICLA sp. Plate XXIII, Figs. 2, 2a. Pyropsis (?) sp. Clark, 1895, Johns Hopkins Uniy. Cire., vol. xv, p. 4. Pyropsis sp. Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 67, pl. xi, figs. 2a, 2b. (?) Pyropsis pyrula Harris, 1899, Bull. Amer. Pal., No. 11, p. 46 (In part). Description.—Several casts of a large Tudicla have been found at various localities in the Aquia formation. They differ from 7. mary- landica in having a bluntly angulated shoulder. We have not seen the casts from Fort Washington which Professor Harris referred to Pyropsis pyrula but they belong probably to this form. Length (of fragment), 40 mm.; width, 55 mm. Occurrence—AQguia Formation. Clifton Beach, Aquia Creek, Crownsville, Fort Washington (Harris). Collections —Maryland Geological Survey, Cornell University. TUDICLA (?) sp. Plate XXIII, Fig. 4; Plate XXIV, Fig. 6. Description—The cast of a small unknown gastropod is very abund- ant in the indurated ledge at Aquia Creek. It has an obtuse, conic spire, varying in height, and a body whorl much expanded at the top, but diminishing in width below. The beak is moderately long, straight and slender. The spire is wound on or slightly below the shoulder of the whorl. The periphery of the whorl is tuberculate. An imperfect shell having all these characters was also found at Popes Creek. It has a thick shell and is ornamented with distant, raised, revolving lines. Length, 40 (?) mm.; width, 27 mm. Occurrence.—N ANJEMOY FoRMATION. Popes Creek. AQuia Forma- TION. Aquia Creek, Clifton Beach. Collections.—Johns Hopkins University, Maryland Geological Survey. Genus LEVIFUSUS Conrad. LEVIFUSUS TRABEATUS (?) Conrad. Pusus trabeatus Conrad, 1833, Fossil Shells of the Tertiary, No. 3 [1st Edit.], p. 29. Fusus trabeatus Conrad, 1835, Fossil Shells of the Tertiary, No. 3 [2nd Edit.], p. 53, pl. xviii, fig. 1. MARYLAND GEOLOGICAL SURVEY 139 Fusus (Levifusus) trabeatus Clark, 1895, Johns Hopkins Uniy. Cire., vol. xv, p. 4. (In part.) Fusus (Levifusus) trabeatus Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 67. (In part.) Description.—* Shell subfusiform, ventricose, with revolving elevated striae at the base, and more obscure ones on the spire: body whorl with two distinct rows of tubercles, humeral one continued on the spire.” Conrad, 1829. Several fragments of molds of the exterior, as well as less clearly de- fined casts of the interior, have been found. They cannot be identified with L. trabeatus with certainty. The casts from Aquia Creek which were formerly identified with this species are evidently of an indetermi- nate T'udicla. Occurrence—NANJEMOY ForMATION. Popes Creek. Collection —Maryland Geological Survey. LEVIFUSUS TRABEATUS (?) var. Plate XXIII, Fig. 3. Description.—A single, imperfect specimen was found at Woodstock which cannot be distinguished in its present condition from a Fulgur. It would be unwise, however, to assume the presence of that genus in the Eocene without better evidence than a single cast. The specimen is too imperfect for description but a figure is given and the form tenta- tively referred to a variety of the preceding species. The substance of the shell is very thin and apparently smooth. The shoulder is carinate or tuberculate. The suture does not seem to be channeled. Length, 73 mm.; width, 25-40 mm. (flattened). Occurrence.—N ANJEMOY ForMAtTION. Woodstock. Collection. Maryland Geological Survey. Genus METULA Adams. METULA MARYLANDICA N. sp. Plate XXIII, Fig. 5. Description.—Shell small, elongate, six-whorled; sculpture of longitu- dinal folds and elevated revolving ribs; body whorl with thirteen longi- 140 SYSTEMATIC PALEONTOLOGY tudinal folds, and about fifteen, raised, obtusely rounded, revolving ribs becoming alternate toward the base; other whorls with six ribs; lines of growth fine and sharp; outer lip with ten, irregularly spaced teeth; canal short, shghtly curved. Length, 11 mm.; width, 5 mm. Occurrence.—AQuIA FORMATION. 2 miles below Potomac Creek, Po- tomac Creek, 1 mile southeast of Mason Springs. Collection. Maryland Geological Survey. Genus CHRYSODOMUS Swainson. CHRYSODOMUS ENGONATUS (Heilprin). Plate XXIII, Fig. 6. Pusus (Hemifusus?) engonatus Heilprin, 1880, Proc. Acad. Nat. Sci. Phila., vol. XXKV, p. 372, pl. xx, fig. 8. Description.—* Shell turreted, of about ten volutions, the first three whorls smooth and convex, the remainder strongly carinated, and trans- versed by numerous fine revolving lines, which on the median portion of the body whorl alternate with intermediate finer striae; body whorl impressed immediately below the carination (shoulder angulation); lines of growth sinous, and approximating the characteristic lines of the Pleurotomidae; aperture considerably exceeding the spire in length; columella shghtly arcuate, and presenting a rudimentary fold at about its central portion.” MHeilprin, 1880. Length, 33 mm.; width, 16 mm. Occurrence—AQquia ForMATION. 2 miles below Potomac Creek, Po- tomac Creek. Collections —Maryland Geological Survey, Philadelphia Academy of Natural Sciences. Genus PSEUDOLIVA Swainson. PSEUDOLIVA sp. Plate XXIII, Fig. 7. Description.—Only internal casts of this form have been found. They are not unlike in size and shape to P. venusta (Conrad), but it is not safe to attempt a specific determination. MARYLAND GEOLOGICAL SURVEY 141 Length, 30 mm.; width, 17 mm. Occurrence—AQuia ForMATION. Upper Marlboro, Hardesty. Collection.—Maryland Geological Survey. Superfamily TAENIOGLOSSA. Family TRITONIDAE. Genus TRITONIUM Link. TRITONIUM SHOWALTERI (Conrad). Plate XXIV, Figs. 1, 1a. Simpulum showalteri Conrad, 1860, Jour. Acad. Nat. Sci. Phila., vol. iv, p. 292, pl. xlvii, fig. 11. Description.—* Fusiform; whirls eight, angular, periphery of angle acute, situated below the middle of the whirl; whirls of spire costate longitudinally, but not very distinctly; revolving lines closely arranged, fine, with a few distant prominent lines; three first whirls of the spire smooth, the next two tuberculated; angle tuberculated; a promi- nent, acute line on the body whirl runs from the upper extremity of the aperture, and a similar finer line between it and the angle above; colum- ella rugose, with a prominent fold near its upper end; labium dentate within.” Conrad, 1860. Length, 26 mm.; width, 13 mm. Occurrence—AQutIa Formation. Mouth of Paspotansa Creek, 2 miles below Potomac Creek. Collection—Maryland Geological Survey. Family DOLIIDAE. Genus PYRULA Lamarck. PYRULA PENITA VAR. Conrad. Plate XXIV, Fig. 2. Pyrula penita Conrad, 1833, Fossil Shells of the Tertiary, No. 3 [Ist Edit.], p. 82. Pyrula cancellata Lea, 1833, Contrib. to Geol., p. 154, pl. v, fig. 160. Pyrula elegantissima Lea, 1833, Contrib. to Geol., p. 155, pl. v, fig. 161. Pyrula tricarinata Conrad, 1835, Fossil Shells of the Tertiary, No. 5 [2nd Edit.], p. 38, pl. xv, fig. 6. Description. Shell subfusiform, reticulated, with three carinations on the body whorl: striz alternating in size: five volutions; spire ele- vated and pointed. Lip thickened toward the margin. 142 SYSTEMATIC PALEONTOLOGY “Variety, C. Destitute of carinations, and probably the young shell. Length about an inch.” Conrad, 1833. Several specimens have been found which are very close to this species. They are nearer the Variety C. suggested by Conrad and named P. ele- gantissima by Lea. Length, 27 mm.; width, 12 mm. Occurrence.—NANJEMOY FoRMATION. Popes Creek. Collection.—Maryland Geological Survey. PYRULA (?) sp. lel SOM, Wave, 8, Description.—Shell thin; body whorl large, convex; sculpture of nu- merous, closely set, revolving, impressed lines, very strongly and con- stantly punctate. Only one specimen has been found and it is very imperfect. The spire is entirely gone. Length (of fragment), 14 mm.; width, 11 mm. Occurrence.—N ANJEMOY FoRMATION. Popes Creek. Collection Johns Hopkins University. Genus FULGUROFICUS Sacco. FULGUROFICUS ARGUTUS Clark. Plate XXIV, Figs. 3, 3a. Pulgur argutus Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 4. Hulguroficus argutus Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 68, pl. xii, figs. 6), Hi Fulguroficus triserialis Harris, 1899, Bull. Amer. Pal., No. 11, p. 67, pl. viii, fig. 17. (In part.) Description.—* Shell moderately short, with four or five whorls; first two whorls apparently smooth; third whorl with faintly impressed spiral lines and minute transverse riblets; later whorls with spinous tubercles at the shoulder; body whorl also with two lower rows of tubercles ar- ranged along strongly elevated spiral ridges and transversely placed vertically above one another; ten to fourteen tubercles in each row; nu- merous fine spiral threads also pass over the spinous ridges and inter- MARYLAND GEOLOGICAL SURVEY 143 spaces; lines of growth somewhat irregular; canal rather long, narrow.” Clark, 1896. This species differs from /’. triserialis Whitfield in having the three rows of tubercles of nearly equal strength, and spaced at nearly equal distances, in having more elevated spire, and in having that portion of the body whorl, of which the middle row of tubercles is in the center, uniformly convex throughout, instead of sharply angulated at the shoulder and nearly flat below. Length, 27 mm.; width, 18 mm. Occurrence.—NANJEMOY FormMATION. Woodstock, Aguria Forma- TION. Potomac Creek, 2 miles below Potomac Creek, Pomonkey Neck, Upper Marlboro. Collections—Maryland Geological Survey, U. 8. National Museum, Philadelphia Academy of Natural Sciences, Johns Hopkins University. Genus FUSOFICULA Sacco. FUSOFICULA JUVENIS (Whitfield). Plate XXIV, Figs. 4, 4a. Pyrula juwvenis Whitfield, 1865, Amer. Jour. Conch., vol. i, p. 259. Fusoficula juvenis Harris, 1899, Bull. Amer. Pal., No. 11, p. 66, pl. viii, figs. 15, 16. Desecription—* Shell small and fragile; spire elevated; columella slender, slightly bent; aperture large, elongate, ovate or sub-elliptical; volutions three; marked on the periphery by three distinct carinae or sub- angular revolving ridges, the upper one marked with closely arranged, longitudinally elongated nodes, the others simple; entire surface marked by very fine revolving lines, which are somewhat fasciculate below the lower carina, there being three finer ones between each large one.” Whitfield, 1865. A single specimen of typical form and excellent state of preservation © was found. Leneth, 23 mm.; width, 11 mm. Occurrence—AQutIA ForMATION. 2 miles below Potomac Creek. Collection —Maryland Geological Survey. 144 SYSTEMATIC PALEONTOLOGY Family CASSIDIDAE. Genus MORIO Montfort. MoRIO BREVIDENTATA (Aldrich). Plate XXIV, Fig. 7. Cassidaria brevidentata Aldrich, 1885, Jour. Cin. Soc. Nat. Hist., p. 152, pl. iii, fig. 20. Description.—* Shell, oblong-oval, whorls seven;* suture, channeled; surface covered with fine revolving striae; coarser, distant lines upon the body whorl, giving the shell the carinated aspect of the genus; lines of growth fine, a few coarser ones showing on the line of the tubercles; apex, smooth; whorls of the spire carinate and slightly tubercled; a row of upright longitudinal nodes on the shoulder of the body whorl, none below; a single, strong varix on the body whorl; aperture, ovate; inner lp spreading over the whorl, with three plications on the upper part, smooth in the central part and plicate below; outer lip reflected, plicate on the inner edge above and below, smooth in the center; canal, narrow, strongly twisted.” Aldrich, 1885. Length, 30 mm.; width, 20 mm. Occurrence—AQUIA FORMATION. 1 mile southeast of Mason Springs, 2 miles below Potomac Creek. Collection.—Maryland Geological Survey. Family CYPRAEIDAE. Genus CYPRAEA Linné. CypRAEA smiTHit Aldrich. Plate XXIV, Fig. 8. Cypraea smithii Aldrich, 1856, Geol. Survey, Ala., Bull. 1, p. 35, pl. v, fig. 3. Description.—* Shell oblong-ovate, rather flat, surface smooth; labium crenulate within, smooth on the base and flattened, reflected somewhat and raised above base of shell; aperture slightly crenulate within, ex- panded below.” Aldrich, 1886. Fragments of a Cypraea which in their somewhat imperfect condition show no characters which would prevent their being referred to C. smith are fairly abundant in the Potapaco member, but seem to be much restricted in vertical range. rm MARYLAND GEOLOGICAL SURVEY 145 Length, 18 mm.; width, 15 by 8 mm. (crushed). Occurrence—NANJEMOY ForMATION. West of Port Tobacco, 4 mile below Chapel Point, Head of Nanjemoy Creek. Collection.—Maryland Geological Survey. Family STROMBIDAE. Genus CALYPTRAPHORUS Conrad. CALYPTRAPHORUS JACKSONI Clark, Plate XXV, Figs. 1, 1a, 2. Calyplrophorus jacksoni Clark, 1895, Johns Hopkins Univ. Circ., vol. xv, p. 4. Calyptrophorus jacksoni Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 68, pl. xii, figs. 2a, 20. Description.—* Shell large, solid, many whorled; spire prolonged, acu- minate; surface of adult covered with thick, calcareous deposit, entirely enveloping the whorls; inner lip thickened with extensive -callosity.” Clark, 1896. This very remarkable form is quite distinct from any other species, but some of the Gulf types approach it in size and amount of callosity. Some of the largest specimens of C. trinodiferus Conrad show certain points of similarity, but the Maryland species cannot be confounded with it. In the absence of young shells, the character of the surface decoration is unknown. A large number of specimens have been found in the South River area. Length (restored), 102 mm.; width, 44 mm. Occurrence—AQquia ForMaATIon. South River, Upper Marlboro. Collections—Maryland Geological Survey, Johns Hopkins University, Museum of Comparative Zoology. CALYPTRAPHORUS TRINODIFERUS Conrad. Plate XXV, Fig. 3. Calyptraphorus trinodiferus Conrad, 1857, Proc. Acad. Nat. Sci. Phila., vol. is, p. 166. Calyptraphorus trinodiferus Conrad, 1860, Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. iv, pl. xlvii, fig. 29. Description Subfusiform, with three distinct nodes on the upper part of the body volution; spire subtriangular, having curved longitu- 10 146 SYSTEMATIC PALEONTOLOGY dinal ribs visible beneath the tunic; rostrum of the spire elongated and curved; labrum with a prominent angle above.” Conrad, 1857. Length, 45 mm.; width, 18 mm. Occurrence.—NANJEMOY ForMATION. Potomac Creek (Zone 11). Aguta ForMATION. 2 miles below Potomac Creek. Collection.—Maryland Geological Survey. CALYPTRAPHORUS TRINODIFERUS (?) VAR. Plate XXV, Figs. 4, 4a. Description—TVhis form has the prolonged spire and longitudinal rib- bing of C. trinodiferus, differing from it only in lacking the nodes. It might perhaps be referred to a variety of C. velatus, but the characters which separate it from C. velatus seem less likely to be accidental than those separating it from C. trinodiferus. In the Philadelphia Academy of Natural Sciences are a few specimens of C. velatus which have the prolonged spire of this form, but none have the ribbing on the spire. Length, 46 mm.; width, 15 mm. Occurrence.—NANJEMOY ForRMATION. Popes Creek. AQguia Forma- TION. 1 mile southeast of Mason Springs. Collection.—Maryland Geological Survey. Family APORRHAIDAE. Genus APORRHAIS da Costa. APORRHAIS POTOMACENSIS Nn. sp. Plate XXV, Figs. 5, 6. Description.—Shell fusiform; spire elevated, pointed; body whorl large; outer lip much expanded; digitations, two, slender and long; pos- terior digitation about twice as long as the anterior; callus on the inner lip thick; whorls strongly convex and somewhat angulated below the middle; body whorl with two obtuse revolving ribs, which extend down the middle of the digitations, and disappear in the opposite direction beneath the callus on the labium; about twenty longitudinal ribs on each whorl, with a deep curve below the suture, overridden by fine, raised, close-set, revolving lines. ~~ heat, MARYLAND GEOLOGICAL SURVEY 147 Length, 25 mm.; width (of body whorl), 10 mm.; length of posterior digitation, 22 mm. Occurrence—AQquta Formation. 1 mile northeast of Piscataway, Paspotansa Creek, 2 miles below Potomac Creek. Collection—Maryland Geological Survey. Family TURRITELLIDAE. Genus TURRITELLA Lamarck. TURRITELLA MORTONI Conrad. Plate XX VI, Figs. 1-5. Turritella mortoni Conrad, 1830, Jour. Acad. Nat. Sci. Phila., vol. vi, p. 221, pl. x, fig. 2. Turritella mortoni Conrad, 1832, Fossil Shells of the Tertiary, No. 5 [2nd Edit.], p. 40, pl. xv, fig. 11. Turritella mortoni Morton, 1884, Synopsis Organ. Rem. Cretaceous Group, App., p. 4. Turritella mortoni H. C. Lea, 1848, Proc. Acad. Nat. Sci. Phila., vol. iv, p. 107. Turritella mortoni Conrad, 1865, Amer. Jour. Conch., vol. i, p. 32. Turritella mortoni de Gregorio, 1890, Ann. Geol. et Pal., p. 122, pl. xi, fig. 7. Turritella mortoni var. postmortoni Harris, 1894, Amer. Jour. Sci., ser. iii, vol. xlvii, p. 303, figs. 1, 2, 3. Turritella mortoni Clark, 1895, Johns Hopkins Univ. Circ., vol. xy, p. 4. Turritella mortoni Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 69, pl. xili, figs. la—le. Turritella mortoni Harris, 1899, Bull. Amer. Pal., No. 11, p. 74, pl. x, figs. 3, 4. Description. Shell turreted, conical, thick, with revolving distant, and finer intervening striae; whorls with an elevated acute carina near the base of each; volutions about eleven; the striae are largest on the elevations of the whorls, which are slightly concave above, and abruptly terminate at the sutures; the lines of growth on the last whorl are strong and much undulated.” Conrad, 1830. This important species was one of the first to be recognized in the Maryland Eocene, and has been generally regarded as one of the most characteristic, as it is one of the most common forms. At times it makes up whole beds, as shown in the Paspotansa member of the Aquia formation at Aquia Creek, Potomac Creek, and other neighboring lo- calities. Turritella mortont shows very great variations in the form and deco 148 SYSTEMATIC PALEONTOLOGY ration of the whorls, and if it were not for the great number of inter- mediate types one might readily establish several independent species. Some specimens have nearly equally rounded whorls with evenly spaced spiral lines, while others are prominently carimated toward the base of the whorl and the spiral threads are irregularly spaced, varying in prominence and number. A variety named postmortonit by Harris is characterized by its rather smaller size, plainer surface, and extremely sharp basal carina. Figure 5 represents this form. Length, 130 mm.; width, 33 mm. ~ Occurrence—AQguis Formation. Fort Washington, 1 mile northeast of Piscataway, Northwest of Piscataway (W. of Tinkers Cr.), Brooks Es- tate near Seat Pleasant, Glymont, Liverpool Point, Clifton Beach, 1 mile southeast of Mason Springs, Aquia Creek, Potomac Creek, Upper Marlboro, Sheckels Farm near South River, 1 mile west of Hardesty,. Rolph’s Landing. Coilections—Maryland Geological Survey, Johns Hopkins University, U.S. National Museum, Philadelphia Academy of Natural Sciences. TURRITELLA HUMEROSA Conrad. Plate XX VII, Figs. 1, 1a. Turritella humerosa Conrad, 1835, Trans. Geol. Soc., Penn., p. 340, pl. xiii, fig. 3. Turvritella humerosa H. C. Lea, 1848, Proc. Acad. Nat. Sci., Phila., vol. iv, p. 107. Turritella humerosa Conrad, 1865, Amer. Jour. Conch., vol. i, p. 32. Turritella humerosa Conrad, 1866, Smith. Mise. Coll. (200), p. 11. Turritella humerosa Harris, 1894, Amer. Jour. Sci., ser. iii, vol. xlvii, p. 303. Turritella humerosa Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 4. Turritella humerosa Clark, 1896, Bull. 141, U. S. Geol. Survey, p. 70, pl. xiv, fig. 1. Turritella humerosa Harris, 1899, Bull. Amer. Pal., No. 11, p. 75, figs. 5, 6, 7. Description—* Shell turreted, subulate; whorls with fine regular re- volving striae; an obtuse slight elevation on the summit, a shallow groove at the base of each.” Conrad, 1835. Turritella humerosa, although not an uncommon species, is far less frequent than 7’. mortoni. It is very readily separated from the latter by its flat whorls and prominent subsutural carina, which makes the whorls of nearly equal diameter above and below. —— MARYLAND GEOLOGICAL SURVEY 149 This species apparently never reaches the dimensions of 7’. morlont, but is commonly associated with it. Like 7’. mortoni, it is largely con- fined to the Paspotansa member of the Aquia Formation. ~ Length, 140 mm.; width, 25 mm. Occurrence—AQquia Formation. Fort Washington, Clifton Beach, Aquia Creek, 1 mile southeast of Mason Springs, Glymont, Mouth of Paspotansa Creek, 1 mile northeast of Piscataway, Near Annapolis, Be- tween Buena Vista and Collington, Tinkers Creek, Liverpool Point, Upper Marlboro, Sheckels Farm near South River, Brooks Estate near Seat Pleasant. Collections —Maryland Geological Survey, Johns Hopkins University, U. 8S. National Museum, Philadelphia Academy of Natural Sciences. 'TURRITELLA POTOMACENSIS 0. sp. Plate XX VII, Figs. 2, 3. Description—Shell slender, elongate; whorls many; each whorl cari- nated at the base, diminishing sharply in diameter toward the apex, and concave in the middle; sculpture consisting of one or two strong, ele- vated carinae at the base of the whorl, and about five moderately strong ones, irregularly spaced above them, and between these secondary alter- nating threads and fine, raised, revolving lines; some of the carinae, especially those toward the middle of the whorl, are beaded. Length, 45 mm.; width, 10 mm. Occurrence-—N ANJEMOY ForMATION. Popes Creek, Woodstock. Collection Maryland Geological Survey. Genus MESALIA Gray. MESALIA OBRUTA (Conrad). Plate XXVII, Fig. 4. Turritella obruta Conrad, 1833, Fossil Shells of the Tertiary, No. 4, p. 45; No. 3 [2nd Edit.], 1835, p. 40. pl. xv, fig. 12. Turritella venusta Conrad, 1855, Trans. Geol. Soe., Penn., vol. i, p. 536. Description.—* Subulate, with about eleven slightly convex volutions, with about seven sharp elevated striae on each, and intermediate fine 96¢ crowded lines; space about the suture indented.” Conrad, 1833. 150 SYSTEMATIC PALEONTOLOGY This form is very abundant in the Nanjemoy formation, and occurs near the top of the Aquia formation at Upper Marlboro, in the indurated ledge and just above it, and also in the same bed near South River bridge. Length, 30 mm.; width, 10 mm. Occurrence—NANJEMOY Formation. Popes Creek, Woodstock. Aquia Formation. Upper Marlboro, Sheckels Farm near South River. Collection Maryland Geological Survey. ; Family VERMETIDAE. Genus VERMETUS Adams. VERMETUS sp. Plate XX VII, Figs. 5, 5a, 6, 7. Vermetus sp. Clark, 1895, Johns Hopkins Univ. Circ., vol. xv, p. 4. Vermetus sp. Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 71, pl. xiv, figs. 2a, 20. Description—Fragmentary masses of this form are found at various points in the Potomac River region, but no specimen sufficiently well preserved for specific determination has been obtained. 'The fragments, however, probably represent a new species. The form is characterized by longitudinal furrows, giving it a somewhat angulated appearance, and by transverse, scaly lines interrupted by the furrows. The average diameter of the tubes is about 2 mm. Occurrence—AQut1A Formation. Piscataway Creek, Potomac Creek, Rolph’s Landing, Upper Marlboro. Collections—U. 8S. National Museum, Johns Hopkins University, Maryland Geological Survey. Family NATICIDAE. Genus NATICA Lamarck. NATICA CLIFTONENSIS Clark. Plate XXVIII, Fig. 1. Natica cliftonensis Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 4. Natica cliftonensis Olark, 1896, Bull. 141, U. 8. Geol. Survey, p. 69, pl. xii, fig. 4. Description.—* Shell small, with four or five whorls; spire low; body whorl much inflated; suture well marked; surface smooth, except for lines of growth; aperture large, with thick callus.” Clark, 1896. MARYLAND GEOLOGICAL SURVEY 151 In addition to the type we have only a crushed Natica from Wood- stock that may represent this species. Length, 10 mm.; width 12 mm. Occurrence.—NANJEMOY FormMATION. Woodstock. (7) AQgura For- MATION. Clifton Beach. Collections—Maryland Geological Survey, Johns Hopkins University. Genus LUNATIA Gray. LUNATIA MARYLANDICA Conrad. Plate XXVIII, Figs. 2, 2a, 3. Lunatia marylandica Conrad, 1865, Amer. Jour. Conch., vol. i, pp. 26, 211, pl. xxi, alee tale LTunatia marylandica Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 4. Lunatia marylandica Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 69, pl. xii, figs 3da—se. ef. Natica eminula var. Harris, 1899, Bull. Amer. Pal., No. 11, p. 88, pl. xi, fig. 22. Description Suborbicular or subovate, volutions 5; spire short, whorls convex, subcontracted below the suture; labium with a callus on the upper part, reflected over the umbilical margin; umbilicus moderate in outline, profound, showing most of the volutions.” Conrad, 1865. The stratigraphic and geographic range of this species is very great. It is larger, however, and more abundant in the lower beds of the Aquia formation. The affinities of the species are with L. eminula (Conrad) of Alabama, especially with ZL. eminula var. Harris, of the Alabama Chickasawan, which is an intermediate member of a series of which the Claibornian L. eminula and L. marylandica are end members. The separation of these species is very difficult, and possibly all the forms ought to be referred to LZ. eminula which is the older name. The Maryland forms show almost, if not quite, the complete range of varia- tion of the series. Length, 32 mm.; width, 30 mm. Occurrence—N ANJEMOY FORMATION. East and west of Port Tobacco, Woodstock. AgurA Formation. 1 mile northeast of Piscataway, Po- tomac Creek, 2 miles below Potomac Creek, Upper Marlboro, Liverpool Point, Mouth of Paspotansa Creek, Aquia Creek, 1 mile southeast of Mason Springs, Glymont, Hardesty, Fort Washington. 152 SYSTEMATIC PALEONTOLOGY Collections—Maryland Geological Survey, Johns Hopkins University, U.S. National Museum, Philadelphia Academy of Natural Sciences. Family CAPULIDAE. Genus CALYPTRAEA Lamarck. CALYPTRAEA APERTA (Solander). - Plate XXVIII, Figs. 4, 5. Trochus apertus Solander, 1766, Foss. Haut., p. 9, figs. 1, 2. Calyptraea trochiformis Lamarck, 1804, Ann. Mus. d’Hist. Nat., vol. i, p. 15, fig. 3- Calyptraea trochiformis Clark, 1595, Johns Hopkins Uniy. Circ., vol. xv, p. 4. Calyptraea trochiformis Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 70. Calyptraea aperta Harris, 1899, Bull. Amer. Pal., No. 11, p. 84, pl. xi, figs. 15-16. Description—Shell orbicular, thin, obtusely conical; volutions three or four; apex subcentral; later whorls spinose; whole surface (except protoconch) roughened with irregular, wavy lines of growth, or a vermi- cular shagreening; septum slightly concave; pillar reflected, giving the appearance of an umbilicus. This species is represented, usually in a poorly preserved state, in nearly all the beds and localities of the Maryland Eocene. The largest specimens are in the Aquia formation. Length, 15 mm.; width, 28 mm. Occurrence—NANJEMOY ForMaATIon. Popes Creek, Woodstock, East and west of Port Tobacco, $ mile below Chapel Point. Agurta Forma- tion. Fort Washington, Glymont, Clifton Beach, Liverpool Point, Up- per Marlboro, Aquia Creek, Potomac Creek, 2 miles below Potomac Creek, 1 mile southeast of Mason Springs. Collection.— Maryland Geological Survey. Family LITTORINIDAE. Genus LITIOPA Rang, LITIOPA MARYLANDICA N. sp. Plate XXVIII, Figs. 6, 6a. Description.—Shell thin, with six whorls; the first two whorls smooth, the third with fine, closely-set, revolving striations from suture to su- MARYLAND GEOLOGICAL SURVEY W753 ture, the fourth with striations on the upper half, the lower half being smooth, the fifth and sixth (body) whorls smooth, except for very faint, revolving lines, which are less distinct than the lines of growth, and about eight, sharp, revolving lines around the umbilicus; callosity on the labium thin; umbilicus moderate; mouth large; columella concave above. Length, 8 mm.; width, 4 mm. Occurrence. Aquta FormMAtTION. 2 miles below Potomac Creek. Collection.—Maryland Geological Survey. Superfamily PTENOGLOSSA. . Family SOLARIIDAE. Genus SOLARIUM Lamarck. SOLARIUM sp. Plate XXVIII, Figs. 7, 7a. Mp Solarium sp. Clark, 1895, Johns Hopkins Uniy. Cire., vol. xv, p. 5. Solarium sp. Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 71, pl. xiv, figs. 4a, 4b. No new material belonging to this genus has been obtained except an indeterminate fragment from near Mason Springs. Neither this, nor the cast from Aquia Creek, give any clew to the specific characters. Length, 6 mm.; width, 16 mm. Occurrence—AQutia Formation. Aquwia Creek, 1 mile southeast of Mason Springs. Collection. Johns Hopkins University, Maryland Geological Survey. Family SCALARIIDAE. Genus SCALA Klein. SCALA VIRGINIANA Clark. Plate XXVIII, Figs. 8, 8a, 9, 9a. Scala virginiana Clark, 1895, Johns Hopkins Uniy. Cire., vol. xv, p. 4. Scala virginiana Clark, 1896, Bull. 141, U.S. Geol. Survey, p. 71, pl. xiv, figs. 3a, 30. Description.—* Shell probably seven- or eight-whorled; surface coy- ered with a uniform, fine, spiral striation; varices fifteen to the whorl, 154 SYSTEMATIC PALEONTOLOGY inflected forward and prominent; some of the varices are more promi- nent than others, and in a few instances are partially divided by a central groove; aperture nearly round.” Clark, 1896. Some specimens show a large umbilicus, in others it is absent. Length, 22 mm.; width, 14 mm. Occurrence—AQquia Formation. Aquia Creek, Potomac Creek. Collection.—U. 8. National Museum, Philadelphia Academy of Natural Sciences. SCALA POTOMACENSIS N. sp. Plate XXVIII, Fig. 10. Description—Shell elongate, moderately slender, eight-whorled; mouth round; base with numerous, closely-set, revolving lines and folds radiating to the varices; whorls closely-set; moderately and uniformly convex; varices low, obtuse, twenty-five on the body whorl, and about as many on the whorls of the spire, stronger than ordinary, and occurring at irregular intervals; raised revolving threads, about 30 in number, alternating and doubly alternating in strength, run between without crossing the varices. Length, 20 mm.; width, 8 mm. Occurrence—AQuia Formation. 2 miles below Potomac Creek. Collection.—Maryland Geological Survey. ScALA SESSILIS Conrad. Plate DOOViiT mies ia: Seala sessilis Conrad, 1835, Fossil Shells of the Tertiary, No. 4, p. 45. Description. Subulate, with rather thick longitudinal costae, and minute crowded spiral lines; whorls nine, sessile or contiguous; base of the body whorl carinated.” Conrad, 1833. Occurrence.—AQuUIA FORMATION. 2 miles below Potomac Creek. Collection.— Maryland Geological Survey. SCALA CARINATA Lea. Plate XXVIII, Fig. 12. Scala carinata Lea, 1833, Contrib. to Geol., p. 116, pl. ivy, fig, 103. Description —* Shell conical, closely ribbed, carinate on the inferior part of the last whorl; substance of the shell thick; spire elevated, MARYLAND GEOLOGICAL SURVEY Ld: Qt pointed; ribs about twelve, lamelliform; whorls six, rounded; mouth round.” Lea, 1833. Occurrence—AQuiA Formation. 2 miles below Potomac Creek, Up- per Marlboro. Collection Maryland Geological Survey. Superfamily GYMNOGLOSSA. Family PYRAMIDELLIDAE. Genus TURBONILLA Risso. Subgenus PYRGISCUS Philippi. TURBONILLA POTOMACENSIS N. sp. Plate XXIX, Fig. 1. Description—Shell stout; whorls eight, moderately convex; about twenty-five slightly curved, longitudinal ribs on the body whorl, crossed by eight, impressed, revolving lines, which are deepest between the ribs; base of shell with impressed, revolving lines, and faint, radiating ribs; mouth ovate. Length, 10 mm.; width, 4 mm. Occurrence—AQuiA ForMATION. Potomac Creek, 2 miles below Po- tomac Creek. Collection Maryland Geological Survey. Genus TUBA Lea. TUBA MARYLANDICA DN. sp. Plate XXIX, Fig. 2. Description.—Shell elongate; whorls seven, strongly convex, covered with eight raised revolving threads, with narrower interspaces; threads strongly beaded by intersections with raised longitudinal lines. Length, 12 mm.; width, 5 mm. Occurrence—N ANJEMOY FoRMATION. Popes Creek. AqQura Forma- TION. Mouth of Paspotansa Creek, 1 mile southeast of Mason Springs. Collection.—Maryland Geological Survey. 156 SYSTEMATIC PALEONTOLOGY Genus ODOSTOMIA Fleming. ODOSTOMIA TRAPAQUARA (Harris). Plate XXIX, Fig. 3. Syrnola trapaquara Harris, 1895, Proc. Acad. Nat. Sci. Phila., vol. xlvii, p. 77, pl. viii, fig. 10. Description.—*“ Size and general form as indicated by the figure; whorls 7; 1 small, sinistral; 2-7 polished, shghtly tumid, with a well- marked suture; aperture moderate, striate within; one strong plait on the columella.” Harris, 1895. This species has some resemblance to the figure of Acteon melanellus Lea, but it tapers more gradually, has shorter whorls, stronger lines of erowth and no revolving lines (or almost none), while they are strong in A. melanellus. Our specimens are very different from the Chickasawan form—0O. in- significa Aldrich, which Harris regards as a synonym of O. trapaquara. Length, 7 mm.; width, 2.5 mm. Occurrence—AQuia FoRMATION. Potomac Creek, 2 miles below Po- tomac Creek, Upper Marlboro. Collection —Maryland Geological Survey. Family EULIMIDAE. Genus NISO Risso. Niso UMBILICATA (Lea). Plate XXIX, Fig. 4. Pasithea umbilicata Lea, 1838, Contrib. to Geol., p. 103, pl. iv, fig. 85. Description.—< Shell elevated above, rounded below, subcarinate, pol- ished; substance of the shell thin; apex acute; suture lnear; umbilicus large; whorls nine, flattened; mouth subovate, acutely angular above, one-fifth the length of the shell; columella incurved at base; margin en- tire. . . . Its umbilicus is wide, with a large spiral groove. On some of the whorls the line of growth may be indistinctly seen.” Lea, 1833. Length, 24 mm.; width, 5 mm. Occurrence.—AQuIA FoRMATION. Potomac Creek. Collection—Maryland Geological Survey. MARYLAND GEOLOGICAL SURVEY Lb Order ASPIDOBRANCHIATA. Suborder RHIPIDOGLOSSA. Family TROCHIDAE. Genus GIBBULA Risso. GIBBULA GLANDULA (Conrad). Plate XXIX, Fig. 5. Monodonta glandula Conrad, 1830, Jour. Acad. Nat. Sci. Phila., vol. vi, pp. 214, 220, joule vost aan, Uy. Monodonta glandula H. C. Lea, 1848, Proce. Acad. Nat. Sci. Phila., vol. iv, p. 102. Monodonta glandula Conrad, 1866, Smith. Mise. Coll. (200), p. 11. Gibbula glandula Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 5. Gibbula glandula Clark, 1896, Bull, 141, U. 8. Geol. Survey, p. 72, pl. xiv, fig. 5. Description —* Shell conical, with about four convex volutions; re- volving striae fine, crowded and wrinkled; suture deeply impressed; right lip toothed within at the base; margin entire. : “The teeth or tubercles extend to the base of the columella of this shell.” Conrad, 1830. Length, 8 mm.; width, 7 mm. Occurrence.—AQuia Formation. Piscataway (Conrad), Potomac Creek, Upper Marlboro. Collections —Johns Hopkins University, Maryland Geological Suryey, Philadelphia Academy of Natural Sciences. Genus CALLIOSTOMA Swainson. CALLIOSTOMA sp. Description—Two specimens of Calliostoma, both too imperfect either to figure or to describe, were found in the Aquia formation. The one from below Potomac Creek is part of the base of the body whorl. It shows a strong basal carina, and revolving threads of various size, all slightly granulate. The fragment from Upper Marlboro does not show the surface decoration, but has a deep groove in the middle of the whorl. Occurrence—AQuia ForMATION. Upper Marlboro, 2 miles below Po- tomac Creek. Collection Maryland Geological Survey. 158 SYSTEMATIC PALEONTOLOGY Family FISSURELLIDAE. Genus FISSURIDEA Swainson. . FISSURIDEA MARLBOROENSIS ND. sp. Plate XXIX, Figs. 6, 6a. Description—Shell ovate, depressed; apex anteriorly situated, acute; foramen keyhole-shaped, anterior to the apex, plane sloping forward; internal callus shaped like the end of a gun-stock, deeply dinted behind; surface sculptured by fine, impressed, radiating lines, with broad and flat interspaces toward the periphery, raised and rounded toward the apex; interspaces doubly alternating in width or height, every fourth being much wider, while of each group of intervening narrower ones that in the middle is slightly wider than the rest; alternation becomes simple on the posterior slope, with double alternation strongest on the anterior slope. Length, 17.5 mm.; width, 12 mm.; height, 6 mm. Occurrence—Aquia Formation. Upper Marlboro. Collection Maryland Geological Survey. class SCAPHOPODA.. Order SOLENOCONCHIA. Family DENTALIDAE. Genus DENTALIUM Linné. DENTALIUM MINUTISTRIATUM Gabb. Jellgnie. XOXIDKs IRN Ges Dentalium minutistriatum Gabb, 1860, Jour. Acad. Nat. Sci. Phila., 2nd Ser., vol. iv, p. 686, pl. Ixvii, fig. 46. Description Very slightly curved, marked by numerous small lon- gitudinal ribs, all of the same size, no trace of alternation; aperture round.” Gabb, 1860. This form differs from D. mississippiensis in having finer, non-alter- nate ribbing, and not attaining to so great a size. MARYLAND GEOLOGICAL SURVEY 159 The figured specimen (besides which only fragments have been found) is strongly and regularly compressed in the plane at right angles to that of curvature. So natural does the compression appear that the indi- vidual was referred to the genus Compressidens of Pilsbry. But other fragments have been found which have a perfectly round aperture, and faint cracks have been discovered along the lines of greatest curvature of the compressed specimen, and therefore the character must probably be regarded as accidental. Length, 17 mm.; width, 1.75 x 2.5 mm. (flattened). Occurrence.—N ANJEMOY FORMATION. Popes Creek. Collection —Maryland Geological Survey. DENTALIUM MISSISSIPPIENSIS Conrad. Plate XXIX, Fig. 8. Dentalium mississippiensis Conrad, 1848, Jour. Acad. Nat. Sci. Phila., 2nd Ser., vol. Hy Joh Wale aol, sats ass oale Description —* Curved, attenuated above, longitudinally striated, the lines alternating in size... . It differs from D. thalloides in having more numerous and much less prominent lines.” Conrad, 1848. Length, 36 mm.; width, 6 mm. Occurrence—NANJEMOY FORMATION. West of Port Tobacco, 1 mile southeast of Piscataway. AQgui1a Formation. Upper Marlboro. Collection —Maryland Geological Survey. Family SIPHONODENTALIIDAE. Genus CADULUS Philippi. CADULUS ABRUPTUS Meyer and Aldrich. Plate XXIX, Fig. 9. Cadulus abruptus Meyer and Aldrich, 1887, Jour. Cin. Soc. Nat. Hist., vol, ix, No. 2, p. 40, pl. ii, fig. 2. Cadulus bellulus Clark, 1895, Johns Hopkins Uniy. Cire., vol. x¥, p. 5. Cadulus bellulus Clark, 1896, Bull. i¢1, U. 8. Geol. Survey, p. 72, pl. xiv, fig. 6. Description —*“ Rather large, somewhat depressed. Inflation very near to the larger aperture and suddenly decreasing.” Meyer and Al- drich, 1886. 160 SYSTEMATIC PALEONTOLOGY Thin, polished, slightly arched; much contracted near the anterior extremity; anterior opening subcireular, posterior simple. This species differs from C. subcoarctatus Gabb in having the con- striction begin much nearer the aperture. There is no longitudinal striation. Length, 8 mm.; width, 1.25 mm. — Occurrence.—N ANJEMOY Formation. Woodstock, Head of Nanjemoy Creek, East and west of Port Tobacco, 1$ and 24 miles above Popes Creek, 1 mile southeast of Piscataway, Upper Marlboro (deep cut near Chesapeake Beach R. R. station), Well at Chesapeake Beach (90-92 feet). -AqutA Formation. Aquia Creek, Liverpool Point, Clifton Beach, 1 mile northeast of Piscataway. Collection.—Maryland Geological Survey, Johns Hopkins University. Gees P BLEC POI A. Order TELEODESMACEA. Family TEREDINIDAE. Genus TEREDO Linné. TEREDO VIRGINIANA Clark. Plate XXX, Figs. 1, la, 2, 2a, 3. Teredo virginiana Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 5. Teredo virginiana Clark, 1896, Bull. 141, U.S. Geol. Survey, p. 72, pl. xv, figs. 5a@—5e. Teredo virginiana Dall, 1898, Trans. Wagner Free Inst. Sci., vol. iii, part iv, p. 813. Description —“ Shell unknown; tube thick, cylindrical, irregularly curved, rapidly tapering; surface smooth, or with fine lines of growth; prominent transverse segment near posterior extremity of the tube in some of the forms.” Clark, 1896. This type compared with the forms described from the Alabama Ter- tiary shows various points of dissimilarity, and even in the absence of the valves seems, from its common occurrence, worthy of a name. The tubes often occur in large masses in pieces of lignite. Diameter of tube (maximum), 5 mm. Occurrence—NANJEMOY Formation, $ mile below Chapel Point. Woodstock, Hills Bridge, West of Port Tobacco, Upper Marlboro (deep oT MARYLAND GROLOGICAL SURVEY 16] cut near Chesapeake Beach R. R. station). Aguia Formation, Upper Marlboro, 2 miles below Potomac Creek, 1 mile southeast of Mason Springs, Clifton Beach, 1 mile northeast of Piscataway. Collections —Johns Hopkins University, Maryland Geological Survey, Philadelphia Academy of Natural Sciences. Family PHOLADIDAE. Genus PHENACOMYA Dall. PHENACOMYA PETROSA (Conrad). Plate XXX, Figs. 4, 4a, 4b. Pholas petrosa Conrad, 1842, Proc. Nat. Inst., Bull. ii, p. 193, pl. ii, fig. 4. Pholas petrosa Conrad, 1846, Amer. Jour. Sci., ser. ii, vol. i, p. 215, pl.i, fig. 1. Pholas petrosa H. C. Lea, 1848, Proc. Acad. Nat. Sci. Phila., vol. iv, p. 104. Pholas petrosa Conrad, 1865, Amer. Jour. Conch., vol. i, p. 2. Pholas petrosa Conrad, 1866, Smith. Mise. Coll. (200), p. 9. Pholas (?) petrosa Clark, 1895, Johns Hopkins Uniy. Cire., vol. xv, p. 5. Pholas (?) petrosa Clark, 1896, Bull. 141, U. 8S. Geol. Survey, p. 73, pl. xv, figs. la—le. Phenacomya petrosa Dall, 1898, Trans. Wagner Free Inst. Sci., vol. iii, part iv, p. 825. Description.‘ Ovate-acute; anteriorly profoundly ventricose; radu sharp and numerous; dorsal margin obliquely rectilinear from the sum- mit of the umbo; base obliquely subrectilinear; posterior side produced, cuneiform.” Conrad, 1842. This form is apparently restricted to the limestone ledge, known as Zone 5. Length, 85 mm.; height, 35 mm. Occurrence—AQuid ForMATION. “Piscataway” (Conrad), Fort Washington, Aquia Creek, Clifton Beach. Collections—Johns Hopkins University, Maryland Geological Survey, Philadelphia Academy of Natural Sciences. Family GASTROCHAENIDAE. Genus GASTROCHAENA Spengler. GASTROCHAENA sp. Plate XXX, Fig. 5. Gastrochaena sp. Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 4. Gastrochaena sp. Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 75, pl. xv, fig. 6. Casts of the tubes of Gastrochaena are common in the indurated layer, Zone 5, of the Aquia Creek stage, and also occur at higher horizons. ial 162 SYSTEMATIC PALEONTOLOGY Few of the specimens obtained show any traces of the shell substance, and rarely impressions of the transverse striations of the tube wall. Occurrence—AQuia Formation. Aquia Creek, Upper Marlboro. Collection.—Johns Hopkins University. Family SAXICAVIDAE. Genus PANOPEA Menard. PANOPEA ELONGATA Conrad. Plate XXXI, Figs. 1-5. Panopaea elongata Conrad, 1835, Trans. Geol. Soc. Penn., vol. i, p. 389, pl. xiii, fig. 1- Panopaea elongata Conrad, 1846, Amer. Jour. Sci., ser. ii, vol. i, p. 215, pl. i, fig. 2. Panopaea elongata H. C. Lea, 1848, Proc. Acad. Nat. Sci. Phila., vol. iv, p. 103. Glycymeris elongata Conrad, 1854, Proc. Acad. Nat. Sci., Phila., vol. vii, p. 29. Glycymeris elongata Conrad, 1865, Amer. Jour. Conch., vol. i, p. 2. Glycymeris elongata Conrad, 1866, Smith. Misc. Coll. (200), p. 8. Panopaea elongata Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 4. Panopaea elongata Clark, Bull. 141, U. 8. Geol. Survey, p. 75, pl. xix, figs. la—Ie. Panopea elongata Dall, 1898, Trans. Wagner Free Inst. Sci., vol. iii, pt. iv, p. 828. Description.—* Shell oblong, produced, surface with distinet con- centric irregular undulations; beaks distant from the anterior margin.” Conrad, 1835. Since at most localities casts alone are found, the following important character has thus been overlooked, viz., that the surface is covered with closely-set, radiating lines of minute granules, which when worn show as lines of punctae, or give the surface an irregularly honeycombed ap- pearance. Length, 85 mm.; width, 43 mm. Occurrence—AQuiA Formation. Fort Washington, Winchester, “ Piscataway ” (Conrad), Tinkers Creek 1 mile north of Piscataway, 1 mile northeast of Piscataway, 1 mile southeast of Mason Springs, Har- desty, R. R. cut near Seat Pleasant, Aquia Creek, Potomac Creek, Pas- potansa Creek, 2 miles below Potomae Creek, Marshall Hall, Upper | Marlboro, Clifton Beach, Rolphs Landing, Glymont. Collections —Johns Hopkins University, Maryland Geological Survey, Philadelphia Academy of Natural Sciences, U. 8. National Museum. MARYLAND GEOLOGICAL SURVEY 163 Family CORBULIDAE. Genus CORBULA Lamarck. CORBULA SUBENGONATA Dall. Plate XXXII, Figs. 1, la, 2, 2a, 2b. Corbula nasuta Clark, 1895, Johns Hopkins Uniy. Cire., vol. xv, p. 5. Corbula nasuta Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 74. Corbula subengonata Dall, 1898, Trans. Wagner Free Inst. Sci., vol. iii, pt. iv, p. 841. Description.—* This form is smaller, less inflated, thinner, and with more nearly parallel dorsal and ventral borders than C. alabamiensis. The sculpture is finer than in C. engonata, which is a more elongated species.” Dall, 1898. The species was thus defined by Dr. Dail to include the forms from the Chickasawan of Alabama, which had previously been called C. ala- bamiensis Lea or C. alabamiensis var. It is probably the ancestral form of the Claibornian C. alabamiensis Lea. This species is very common in the Maryland and Virginia Eocene. Its slightly elevated umbones and the absence of rostrated posterior sur- face separate it from the other species of this genus. In its occurrence it differs from our other Eocene species of Corbula in that it is most abundant in the lower beds. Length, 11 mm.; height, 6 mm. Occurrence—NANJEMOY FormMAtTION. Woodstock, Popes Creek. Aquia Formation. Glymont, Clifton Beach, 6 miles east of Washing- ton, Mattawoman Creek, 2 miles below Potomac Creek, 1 mile southeast of Mason Springs, 1 mile northeast of Piscataway. Collections Maryland Geological Survey, Johns Hopkins University, U.S. National Museum. CORBULA ALDRICHI Meyer. Plate XXXII, Figs. 3, 38a, 4, 4a, 5, 5a, 6, 6a. Corbula aldrichi Meyer, 1885, Amer. Jour. Sci., ser. iii, vol. xxx, p. 67. Corbula aldrichi Aldrich, 1886, Bull. i, Ala. Geol. Survey, p. 83, pl. i, fig. 21. Corbula aldrichi Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 5. Corbula aldrichi Clark, 1896, Bull. 141, U. S. Geol. Survey, p. 74. Description. It has radiating striae on the umbonial part of the surface, a characteristic which I had not seen before in a Corbula.” Meyer, 1885. 164 SYSTEMATIC PALEONTOLOGY “Rounded trigonal; ventricose; posterior side carinated; beak small, curved anteriorly, in the left valve nearly in the middle; right valve briefly rostrated; in both valves the umbonial part is without concentric ribs, but with impressed, radiating lines—the ventral part with con- centric ribs.” Aldrich, 1886. This remarkable form, with its radiating lnes upon the umbonial portions of the shell, is very common. The Maryland form differs in no essential particulars from the Gulf type. Length, 11 mm.; height, 7 mm. Occurrence-—N ANJEMOY Formation. Upper Marlboro (deep cut near Chesapeake Beach R. R. station), East and west of Port Tobacco, Head of Nanjemoy Creek, $ mile below Chapel Point, Popes Creek, 14 miles 4 w Ww above Popes Creek, 24 miles above Popes Creek, Woodstock, 1 mile southeast of Piscataway. Aqura Formation. Aquia Creek, Liverpool Point, Clifton Beach. Collections —Maryland Geological Survey, Johns Hopkins University, U.S. National Museum. CORBULA ONISCUS Conrad. Plate XXXII, Figs. 7, Va, 8, 8a, 8h. 299 Corbula oniscus Conrad, 1833, Amer. Jour. Sci., vol. xxiii, p. 341. Corbula oniscus Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 5. Corbula oniscus Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 75. Corbula (Aloidis) oniscws Dall, 1898, Trans. Wagner Free Inst. Sci., vol. iii, pt. iv p. 845. ’ Description.—* Shell elevated; larger valve ventricose, with profound sulci terminating at the umbonial slope, which is carinated; posterior extremity narrowed and truncated, from the posterior angle of which a carina extends to the apex, nearly parallel with that of the umbonial slope; superior valve concentrically striated. Length, one-third of an inch.” Conrad, 1833. This species, characterized by its solid form and numerous concentric, wrinkled, approximate lines and prominently rostrated posterior sur- face, is common at several localities in the Maryland Eocene. None of the specimens obtained reach the size of the larger individuals in the Gulf Eocene. ety MARYLAND GEOLOGICAL SURVEY 165 Length, 10 mm.; height, 7 mm. Occurrence.—N ANJEMOY FORMATION. ast and west of Port Tobacco, Woodstock, Popes Creek, 24 miles above Popes Creek, Head of Nanjemoy Creek, Upper Marlboro (deep cut near Chesapeake Beach R. R. station), 1 mile southeast of Piscataway. Hills Bridge? Aguta ForMATION. Glymont. Collection—Maryland Geological Survey. Family SOLENIDAE. Genus SOLEN Linné. SOLEN LISBONENSIS (?) Aldrich. Plate XXXIII, Fig. 1. Solen lisbonensis Aldrich, 1886, Bull. i, Ala. Geol. Survey, p. 37, pl. iv, fig. 4. Solen sp. Harris, 1897, Bull. Amer. Pal. No. 9, p. 66, pl. xiv, fig. 9. Solen (Plectosolen) lisbonensis Dall, 1900, Trans. Wagner Free Inst. Sci., vol. iii, pt. v, p. 953. (7) Solen (Plectosolen) lisbonensis var. abruptus Dall, 1900, Trans. Wagner Free Inst. Sci., vol. iii, pt. v, p. 953. Description Shell linear, nearly straight; posterior subtruncate; anterior obliquely rounded with a depressed space behind running to the beaks; lines of growth prominent, bending at right angles along a line running obliquely from the beaks to the junction of the posterior and ventral margins. Anterior widely gaping.” Aldrich, 1886. The references given above are the only records we have of the occur- rence of this genus in the Eocene of Eastern North America. The two specimens from the Potomac River are both imperfect and neither shows any characters upon which they can be specifically separated from S. lisbonensis. The lines of growth on our specimens do not bend quite as sharply as they do in Aldrich’s figure. In this respect they are more like the figure published by Professor Harris. Our specimens are smaller than either of those figured from Alabama. In the publication above noted, Dr. Dall describes a variety abruptus under S. lisbonensis. This differs from our form even more than the typical S. lisbonensis does. 166 SYSTEMATIC PALEONTOLOGY Length (of fragment), 32 mm.; width, 9 mm. Occurrence—NaNJEMOY Formation. 4 mile below Chapel Point, Woodstock. Collections —Maryland Geological Survey, Philadelphia Academy of Natural Sciences (No. 6224). Family TELLINIDAE. Genus TELLINA Deshayes. Subgenus ANGELUS Megerle. TELLINA (ANGELUS) VIRGINIANA Clark. "Plate XXXL, Vie. 3. Tellina virginiana Clark, 1895, Johns Hopkins Univ. Circ., vol. xv, p. 5. Tellina virginiana Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 76, pl. xv, fig. 4. Tellina greggi Harris, 1897, Bull. Amer. Pal. No. 9, p. 72. (In part.) Tellina (Angelus) virginiana Dall, 1900, Trans. Wagner Free Inst. Sci., vol. iii, pt. v, pp. 1015, 1016. Description—* Shell elongated, thin, compressed; posteriorly very short, angular, and slightly folded; anteriorly rounded and elongated; umbones posteriorly situated; two small cardinal teeth and indistinct lateral teeth; pallial sinus obscure. Exterior covered with fine concen- tric lines following lines of growth.” Clark, 1896. This species is more abundant in the Nanjemoy formation, but the specimens from the Aquia formation are much larger. Professor Harris has suggested the identity of this form with T. greggi of Alabama, but further study has shown them to be undoubtedly dis- tinct. Dr. Dall agrees with us in this opinion. Length, 38 mm. (average, 18 mm.); height, 25 mm. (average, 13 mm.). Occurrence.—N ANJEMOY ForMaATIoN. Woodstock, Popes Creek, East and west of Port Tobacco, Charles Branch between Rosaryville and Up- per Marlboro, 24 and 3 miles above Popes Creek. AQguia ForRMATION. Aquia Creek, Clifton Beach, 2 miles below Potomac Creek, 1 mile south- east of Mason Springs, Fort Washington. Collections —Maryland Geological Survey, Johns Hopkins University. MARYLAND GHOLOGICAL SURVEY 167 Section PERONIDIA DALL. TELLINA (PERONIDIA ?) WILLIAMS! Clark. Plate XXXIII, Figs. 2, 2a. Tellina williamsi Clark, 1895, Johns Hopkins Uniy. Cire., vol. xv, p. 5: Tellina williamsi Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 76, pl. xv, figs. da, 36. Tellina subtriangularis Harris, 1897, Bull. Amer. Pal., No. 9, p. 73. (In part). Tellina (Peronidia?) williamsi Dall, 1900, Trans. Wagner Free Inst. Sci., vol. iii, pt. v, p. 1016. Description —* Shell small, rather solid, not strongly inequilateral; posterior shorter; surface ornamented with elevated, close-set ridges or lamellae, increasing in size toward the basal margin; posteriorly suban- gulated; two cardinal teeth, posterior bifid; lateral teeth strongly devel- oped; pallial sinus deep.” Clark, 1896. The question of the identity of this form with Tellina subtriangularis Aldrich of the Alabama Eocene has been carefully considered. Dr. Dall * agrees with us that they are distinct, but Professor Harris * thinks they are the same. 7’. williamsi is more elongate and more strongly sculptured. Length, 12 mm., height, 7 mm. Occurrence—NANJEMOY ForMatTION. Popes Creek, 24 miles above Popes Creek, Woodstock. Aguta Formation. Potomac Creek. Collection—Maryland Geological Survey, Johns Hopkins University. TELLINA (PERONIDIA) PAPYRIA (?) Conrad. (7) Tellina papyria Conrad, 1833, Fossil Shells of the Tertiary, No. 4, p. 41 (fig’d. Amer. Jour. Sci., vol. i, 1846, pl. iv, fig. 7). A single specimen has been found which belongs to neither of the pre- ceding species, and which has the outline of T. papyria. The shell is very thin and has almost disappeared. Length, 35 mm.; height, 26 mm. Occurrence.—AQutia FormMATION. Fort Washington. Collection —Maryland Geological Survey. ! Trans. Wagner Free Inst. Sci., vol. iii, pt. v, 1900, p. 1016. 2 Bull. Amer: Pal., No. 9, 1897, p. 73. 168 SYSTEMATIC PALEONTOLOGY Family VENERIDAE. Genus MERETRIX Lamarck. MERETRIX LENIS (Conrad). Plate XX XIII, Fig. 4. . Cytherea lenis Conrad, 1848, Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. i, p. 130, pl. xiv, fig. 19. ’ Description‘ Longitudinally ovate, thin, ventricose; anterior ex- tremity acutely rounded; posterior end direct, subtruncated; disk with impressed concentric lines, distinct on the sides but obsolete in the middle of the valves; lunule long, cordate, defined by an impressed line; inner margin entire.” Conrad, 1848. This species is distinguished from its associates by its extremely ele- vated beaks, and deep valves. The shell is very thin and fragile and tends to break along radiating lines. The concentric wrinkles and lines of growth are very distinct toward the beak, but become less so toward the periphery. Length, 11 mm.; height, 11 mm. Occurrence.—NANJEMOY ForMATION. Woodstock, Ravine north of Thrift (?). Collections—Maryland Geological Survey, Philadelphia Academy of Natural Sciences (No. 6384). MERETRIX OVATA VAR. OVATA (Rogers). Plate XXXIV, Figs. 1, 1a. Oytherea ovata Rogers, 1837, Trans. Amer. Philos. Soc., vol. v, p. 340; vol. vi, pl. xxvii, fig. 2. (Reprint Geol. of the Virginias, 1884, p. 668, pl. ii, fig. 2.) Cytherea liciata Conrad, 1848, Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. i, p. 131, pl. xiv, fig. 20. Oytherea ovata H. C. Lea., 1848, Proc. Acad. Nat. Sci. Phila., vol, iv, p. 99. Cytherea liciata H. C. Lea, 1848, Proc. Acad. Nat. Sci. Phila., vol. iv, p. 99. Meretrix liciata Conrad, 1854, Proc. Acad. Nat. Sci. Phila., vol. vii, p. 30. Meretrix ovata Conrad, 1854, Proc. Acad. Nat. Sci. Phila., vol. vii, p. 30. Dione ovata Conrad, 1865, Amer. Jour. Conch., vol. i, p. 6. Dione liciata Conrad, 1865, Amer. Jour. Conch., vol. i, p. 6. Dione ovata Conrad, 1866, Smith. Mise. Coll. (200), p. 7. Dione liciata Conrad, 1866, Smith. Mise. Coll. (200), p. 7. Cytherea ovata Clark, 1895, Johns Hopkins Uniy. Cire., vol. xv, p. 5. (In part.) Cytherea ovata Clark, 1896, Bull. 141, U. 8S. Geol. Survey, p. 76. (In part.) { : . : | 4 j —— MARYLAND GEOLOGICAL SURVEY 169 Description.—* Shell subovate, somewhat inflated, with concentric transverse striae, very fine near the umbones, but much coarser near the margin; beaks rather elevated; lunule very indistinct; teeth elevated and straight, the two posterior ones of the left valve small, much compressed, approximate, and nearly parallel; the anterior tooth large and grooved by a deep canal; cavity of shell deep; margin entire; posterior margin straight, and separated from the muscular impression by a fold or groove. Length one and one-tenth of an inch; height eighty-five hundredths of an inch.” Rogers, 1837. This widely-distributed species shows great variation in outline and has been described under several names, of which only the Maryland names are given in the synonymy. ‘The complete species includes J. nuttalliopsis Heilprin with all its varieties, and a number of other Ala- bama names. The species ranges from the base to the summit of the Maryland Kocene, and is very abundant in nearly all localities. The two varieties may be clearly recognized and their separation closely conforms to the stratigraphic divisions. The form originally described by Rogers comes from the Nanjemoy formation. It is smaller, thinner, in general more elongate, and with a less rounded basal margin than the older type. It was this variety that Conrad afterward named liciata. Length, 31 mm.; width, 24 mm. Occurrence.—N ANJEMOY FormMATION. East and west of Port To- bacco, Popes Creek, 1 to 24 miles above Popes Creek, $ mile below Chapel Point, Upper Marlboro (deep cut near Chesapeake Beach R. R. station), Upper Marlboro (southwest of town near forks of roads), Head of Nanjemoy Creek, 1 mile southeast of Piscataway. Collections—Maryland Geological Survey, Johns Hopkins University, Philadelphia Academy of Natural Sciences, U. 8. National Museum. MERETRIX OVATA VAR. PYGA Conrad. Plate XXXIV, Figs. 2, 2a, 3, 3a, 4, 5. Cytherea pyga Conrad, 1848, Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. i, p. 151, pl. xiv, fig. 18. Cytherea pyga H. C. Lea, 1848, Proc. Acad. Nat. Sci. Phila., vol. iv, p. 99. 170 SYSTEMATIC PALEONTOLOGY Meretrix pyga Conrad, 1854, Proc. Acad. Nat. Sci. Phila., vol. vii, p. 30. Dione pyga Conrad, 1865, Amer. Jour. Conch., vol. i, p. 6. Cytherea ovata Clark, 1895, Johns Hopkins Uniy. Circ., vol. xv, p. 5. (In part.) Cytherea ovata Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 76 (In part), pl. xvi, figs. la-lf. Description.—* Suboval, ventricose, thick, with closely arranged ro- bust concentric lines; umbo wide, prominent above; dorsal margin very oblique, rounded; posterior extremity obtusely and obliquely rounded inwards; anterior extremity much narrower than the posterior, and more acutely rounded; lunule lanceolate, defined by a distinct impressed line; cardinal teeth robust. Length, 12; height, 14.” Conrad, 1848. The form described by Conrad under this name was found in the Aquwia formation, and the name as here used is thus restricted. The specimens are large, thick, ventricose, and more nearly oval than the variety from the Nanjemoy formation. Length, 50 mm.; width, 43 mm. Occurrence —Aquia Formation. Potomac Creek, Aquia Creek, Fort Washington, Glymont, Mouth of Paspotansa Creek, Liverpool Point, Sheckel’s Farm near South River, Clifton Beach, 2 miles below Potomac Creek, 1 mile northeast of Grimesville, Upper Marlboro, Hardesty, Brooks Estate near Seat Pleasant, 2 miles west of Collington, Reedy Run (branch of Chickomuxen Creek), Mattawoman Creek (?), 1 mile south- east of Mason Springs. Collections —Maryland Geological Survey, Johns Hopkins University, Philadelphia Academy of Natural Sciences, U. 8. National Museum. MERETRIX SUBIMPRESSA Conrad. Plate XOXO Wiesib; oa, 6, 7, 8, 6a, 95 9a. Cytherea subimpressa Conrad, 1848, Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. i, p. 130, pl. xiv, fig. 26. Cytherea subimpressa H. C. Lea, 1848, Proc. Acad. Nat. Sci. Phila., vol. iv, p. 99. Meretriz subimpressa Conrad, 1854, Proc. Acad. Nat. Sci. Phila., vol. vii, p. 30. Cytherea subimpressa Clark, 1895, Johns Hopkins Univ. Cire., vol. xy, p. 5. Cytherea subimpressa Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 77, pl. xvii, figs. lu-1h. Description.—* Ovate, slightly ventricose, smooth and polished, with concentric, slightly impressed lines on the anterior side; anterior side h 7 ‘ 1 ; MARYLAND GEOLOGICAL SURVEY 171 short, rather acutely rounded; posterior side produced, acutely rounded at the extremity; dorsal margin long, oblique, slightly curved; beaks prominent; lunule lanceolate; defined by a slightly impressed line. Length, 14 inch; height, 8-10 inch.” Conrad, 1848. This species is very abundant in the Woodstock member of the Nan- jemoy formation. Length, 30 mm.; width, 18 mm. Occurrence—NaNJmmMoy Formation. Popes Creek, 1 mile southeast of Piscataway, Woodstock, Upper Marlboro (southwest of town near forks of two roads). Collections —Maryland Geological Survey, Johns Hopkins University, Philadelphia Academy of Natural Sciences. Genus DOSINIOPSIS Conrad DOSINIOPSIS LENTICULARIS (Rogers). Plate XXXV, Figs. la-lg. no Cytherea lenticularis Rogers, 1839, Trans. Amer. Philos. Soc., vol. vi, p. 872, pl. xxviii, fig. 1. Cytherea lenticularis H. C. Lea, 1848, Proc. Acad. Nat. Sci. Phila., vol. iv, p. 99. Artemis lenticularis Conrad, 1855, Proc. Acad. Nat. Sci. Phila., vol. vi, p. 520. Dosinia lenticularis Conrad, 1854, Proe. Acad. Nat. Sci. Phila., vol. vii, p. 50. Dosiniopsis meekii Conrad, 1864, Proc. Acad. Nat. Sci. Phila., vol. xvi, p. 215, and figure in text. Dosiniopsis lenticularis Conrad, 1865, Amer. Jour. Conch., vol. i, p. 6. Dosiniopsis meekii Conrad, 1865, Amer. Jour. Conch., vol. i, p. 6. Dosiniopsis meekii Conrad, 1866, Smith. Mise. Coll. (200), p. 6. Dosiniopsis lenticularis Conrad, 1866, Smith. Mise. Coll. (200), p. 6. Dosiniopsis lenticularis Harris, 1894, Amer. Jour. Sci., ser. iii, vol. xlvii, p. 302. Dosiniopsis lenticularis Clark, 1895, Johns Hopkins Uniy. Cire., vol. xv, p. 5. Dosiniopsis lenticularis Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 78, pl. xviii, figs. la—-lg. Description.—* Shell large, depressed, discoidal, rather thick, length nearly equal to the breadth; transversely striated; lunule long, ovate, obscurely defined by a very faint impressed line; umbones rather de- pressed; beaks small, hardly recurved; teeth straight, divergent; cavity of the shell not deep; margin entire. Diameter about two inches.” Rogers, 1839. The type of the species, as figured and described by Rogers, is a much We SYSTEMATIC PALEONTOLOGY less common form than the variety later described by Conrad under the name of D. meekit. Rogers’s type represents a moderately thin shell with a weak hinge, while the form described by Conrad is a heavy shell with a broad, solid hinge. Every possible gradation between these extremes has been obtained. Length, 70 mm.; height, 70 mm. Occurrence—AQuia Formation. Fort Washington, Glymont, Clif- ton Beach, Potomac Creek, Liverpool Point, Aquia Creek, Mattawoman Creek, 1 mile northeast of Piscataway, Sheckels Farm near South River, Reedy Run (branch of Chickomuxen Creek), 1 mile west of Hardesty, near Hardesty, Brooks Estate near Seat Pleasant, 1 mile northeast of Grimesville, Harrisons Landing, Upper Marlboro, 3 miles west of Pisgah, Fredericktown. Collections —Maryland Geological Survey, Johns Hopkins University, U. S. National Museum, Philadelphia Academy of Natural Sciences. Family CARDIIDAE. Genus PROTOCARDIA Beyrich. PROTOCARDIA LENIS Conrad. Plate XXXVI, Figs. 1, la, 2, 2a, 3. Cardium (Protocardia) lenis Conrad, 1855, Proc. Acad. Nat. Sci. Phila., vol. vii, p. 258. Protocardia virginiana Conrad, 1864, Proc. Acad. Nat. Sci. Phila., vol. xv, p. 211. Protocardia virginiana Conrad, 1866, Smith. Mise. Coll. (200), p. 6. Protocardia virginiana Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 5. Protocardia virginiana Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 81, pl. xxvi, figs. la-le. Protocardia lenis Dall, 1900, Trans. Wagner Free Inst. Sci., vol. iii, pt. v, p. 11138. Description —** Compared with C. nicollettv; wumbo less inflated, pos- terior margin oblique, shell proportionally longer, and the radiating lines 22; in the other 25. The posterior cardinal tooth larger, &c.” Conrad; 1855. “ Cordate, subtriangular, inequilateral, ventricose, thin; radiating lines minute; anterior upper margin very oblique, slightly emarginate, pos- terior side slightly produced, the margin obliquely truncated; post-um- bonal area densely tuberculated on closely arranged striae; posterior car- To MARYLAND GEOLOGICAL SURVEY Wires dinal tooth small, tubercular. Height, 145 inch; length, 1% inch.” Conrad, 1864. This species has a wide vertical and horizontal range in the Maryland Kocene. It is by no means a common form, and good specimens are very rare. Certain Gulf-state forms have been referred to this species, but the recent work of Dr. Dall shows that they are distinct and that this species is apparently restricted to Maryland and Virginia. Length, 42 mm.; width, 42 mm. Occurrence—NansgEMOY Formation. Popes Creek, Woodstock. Aquta Formation. Aquia Creek, Potomac Creek, 1 mile southeast of Mason Springs, 2 miles below Potomac Creek, Upper Marlboro, Rolphs Landing, 1 mile northeast of Piscataway, mouth of Paspotansa Creek. Collections —Maryland Geological Survey, Johns Hopkins University, Philadelphia Academy of Natural Sciences. Family DIPLODONTIDAE. Genus DIPLODONTA Bronn. DIPLODONTA MARLBOROENSIS N. sp. Plate XXXVI, Fig. 4. Description—Shell subcircular, moderately and regularly convex. Beaks depressed, approximate. Lines of growth weak. Surface irregu- larly wrinkled, sometimes smooth and almost polished. Differs from D. hopkinsensis Clark in being larger, more elevated, much less globose, having a less prominent beak, and much weaker and less frequent lines of growth. This species has a resemblance to D. wngulifera Conrad. The resem- blance is especially close with Lea’s figure of that species (described as Egeria rotunda). Length, 18 mm.; width, 16 mm.; depth of valve, 4 mm. Occurrence—AQuia Formation. Upper Marlboro, Sheckel’s Farm near South River. Collection —Maryland Geological Survey. 174 SYSTEMATIC PALEONTOLOGY DIPLODONTA HOPKINSENSIS Clark. Plate XXXVI, Figs. 5, 5a, 6, 7. Diplodonta hopkinsensis Clark, 1895, Johns Hopkins Uniy. Cire., vol. xv, p. 5. Diplodonta hopkinsensis Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 79, pl. xxii, figs. la-ld. c Diplodonta hopkinsensis Dall, 1900, Trans. Wagner Free Inst. Sci., vol. iii, pt. v, 70s iaUsil. Description —* Shell small, suborbicular, globose; surface with fine in- distinct striations; anteriorly and posteriorly rounded.” Clark, 1896. This species has not been found in Maryland, but as it occurs in the same beds in Virginia it will undoubtedly be found in Maryland later, and for this reason the figures and description are reprinted for the benefit of future investigators. Dr. Dall records several localities in the Chickasawan of Alabama. Length, 16 mm.; height, 15 mm. Occurrence—NANJEMOY FormaATION. Evergreen, Va. Collection Johns Hopkins University. Family LUCINIDAE. Genus LUCINA Bruguiere. Lucina AQUIANA Clark. Plate XXXVII, Figs. 1, 1a. Lucina aquiana Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 5. Lucina aquiana Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 78, pl. xx, figs. la, 10- (?) Lucina greggi Harris, 1897, Bull. Amer. Pal. No. 9, p. 70 (In part), pl. xiv, fig. 2a (not fig. 2). Description—* Shell of moderate size, somewhat compressed; surface covered with numerous concentric striae; umbones depressed and acumi- nate on account of prominent, deeply incised lunules; anterior side elon- gate; posterior side rounded; hinge with two cardinal and two lateral teeth.” Clark, 1896. The smaller figure published by Professor Harris of a specimen from srego’s Landing, Ala., is indistinguishable from this species. Length, 18 mm.; height, 18 mm. Occurrence.—AQuia Formation. Aquia Creek, Upper Marlboro. Collections —U. 8. National Museum, Maryland Geological Survey. ed MARYLAND GEOLOGICAL SURVEY io LucINA ASTARTIFORMIS Aldrich. Plate XXXVII, Figs. 2, 2a. Lucina astartiformis Aldrich, 1897, Bull. Amer. Pal. No. 8, p. 15, pl. v, figs. 1, 1a. Description.—* Shell small, rather solid; beak pointed and small; sur- face with numerous concentric raised lamellae which nearly overlap at ventral margin; between the striae are fine radiating lines from beak to margin;*striae terminating at hinge line in raised points; hinge long and narrow; anterior of shell concave along the hinge line; escutcheon smooth; cardinal teeth separated by a deep quadrangular fosset; no lat- erals; muscular impressions distinct; pallial line simple; posterior part of valves somewhat flattened; margin smooth.” Aldrich, 1897. The number of raised lamellae and the distance between them are very variable factors. This species is very rare. Length, 6 mm.; width, 5.5 mm. Occurrence—NANJEMOY ForMATION. 1 mile southeast of Piscata- way, Upper Marlboro (deep cut near Chesapeake Beach R. R. station). Collection —Maryland Geological Survey. LUCINA DARTONI Clark. Plate XXXVII, Figs. 3, 3a, 3b. g Lucina dartoni Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 95. Lucina dartoni Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 79, pl. xx, figs. 2a-2e. Description.—* Shell rather small, suborbicular, thin; surface with fine, thin, distant concentric, lamellated striae, crossed by numerous radial, fine, irregular lines less distant than the concentric lamellae: an- teriorly and posteriorly high shouldered and angulated: lunules large: hinge area narrow; ligament small; muscle impressions shallow; margin simple.” Clark, 1896. Length, 9 mm.; width, 7.5 mm. Occurrence—NaNsJEMOY ForMATION. Popes Creek, 25 miles above Popes Creek, Woodstock. Collections—Johns Hopkins University, Maryland Geological Survey. 176 SYSTEMATIC PALEONTOLOGY LucINA UHLERI Clark. Plate XXXVII, Figs. 4, 5, 6, 7. Lucina uhleri Clark, 1895, Johns Hopkins Uniy. Circ., vol. xv, p. 5. Lucina uhleri. Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 79, pl. xxi, figs. la—1d. (7) Lucina ulrichi Harris, 1897, Bull. Amer. Pal. No. 9, p. 71, pl. xiv, fig. 4. Description —* Shell small, orbicular, slightly tumid; surface with nu- merous uniform, elevated, concentric ridges; anterior and posterior sides rounded; lunules slightly depressed; interior with radiating striae; mar- gin simple.” Clark, 1896. The original figures of this species did not show the muscular scars and the teeth accurately. The figures here published correct these de- fects. It is evident that Professor Harris has speiled the name wlrichi unin- tentionally. The form from Wood’s Bluff is probably the same as that from Maryland. The apparent difference in the hinge, noted by Pro- fessor Harris being an inaccuracy in the old figures which are here re- placed by a correct one. It would be a misfortune if we had to use two names, as nearly alike as whleri and ulrichi, for two forms with as slight differences as these show. This is the most abundant and widely distributed of our Maryland Eocene Lucinas. The types are immature. Length, 9 mm.; height, 8 mm. Occurrence—NANJEMOY ForMATION. Popes Creek, Woodstock. Aquta Formation. Chfton Beach, Upper Marlboro, Potomac Creek, Glymont, 1 mile northeast of Piscataway, Mattawoman Creek, 1 mile southeast of Mason Springs, 2 miles below Potomac Creek, Liverpool Point. Collections —Maryland Geological Survey, Johns Hopkins University. LUCINA WHITEI Clark. Plate XXXVII, Figs. 8, 8a, 9. Lucina whitei Clark, 1895, Johns Hopkins Uniy. Cire., vol. xv, p. 5. Lucina whitei Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 79, pl. xx, figs. 3a—de. Description.—* Shell small, suborbicular, globose; surface with promi- nent concentric lamellae, interrupted posteriorly by shallow fold, extend- MARYLAND GEOLOGICAL SURVEY 177 ing from umbones to posterior basal margin; lunules deeply depressed; anterior side high shouldered, rounded; posterior high shouldered, angu- lated; margin crenulated.” Clark, 1896. Length, 8 mm.; width, 7.5 mm. Occurrence—NANJEMOY Formation. West of Port Tobacco, 4 mile below Chapel Point, Woodstock. Collections —Johns Hopkins University, Maryland Geological Survey. LUCINA sp. A single fragment, evidently of a large Lucina, was found, which is very different from any other form known from Maryland or Virginia. It probably belongs to a new species of Lucina, or to L. claibornensis Con.; but our only specimen is too imperfect to determine. ‘The shell is fragile, moderately thin, and the valves very shallow. It has about forty, rugose, concentric lamellae with faint, wavy, radiating lines be- tween them. Hinge, scars, and pallial line are unknown. Length and height about 30 mm. Occurrence—NANJEMOY ForMAtTION. Popes Creek. Collection—Maryland Geological Survey. Family CARDITIDAE. Genus VENERICARDIA Lamarck. This genus is very abundantly represented in the Maryland Tertiary and especially in the Eocene. The Eocene forms are very numerous and range throughout the entire horizontal and vertical extent of the forma- tions. ‘The variation in form is very great and has led to the establish- ment of several species and varieties, all of which have been referred by most later authors to V. planicosta. Three forms, possessing con- stant differences, may be recognized, and as these are each definitely restricted in stratigraphic range, and are hence of geologic value, they are given names. Rogers’ described from Virginia a species of Venericardia which he called V. ascia. As this form has never been recognized from Mary- 1Trans. Amer. Philos. Soc., vol. vi, 1839, p. 374, pl. 29, fig. 2. 12 178 SYSTEMATIC PALEONTOLOGY land, no reference is made to it in the synonymy. If the figure and description are correct, it is probably a different species from any in Maryland. 5 VENERICARDIA PLANICOSTA VAR. REGIA Conrad. Plate XXXVITI, Figs. 1, 1a; Plate XXXIX, Figs. 1, 1a; Plate XL, Figs. 1, 2, 3. Cardita planicosta Conrad, 1832, Fossil Shells of the Tertiary, No. 1, [1st. edit.] Pa20, pls v, fie. ae Cardita planicosta Morton, 1834, Syn. Org. Rem. Cretaceous Group, App., p. 7. Venericardia planicosta H. C. Lea, 1848, Proc. Acad. Nat. Sci. Phila., vol. iv, p. 107. Venericardia planicosta var. regia Conrad, 1865, Amer. Jour. Conch., vol. i, p. 8. Venericardia planicosta Conrad, 1866, Smith. Mise. Coll. (200), p. 5. Venericardia regia Conrad, 1866, Smith. Misc. Coll. (200), p. 5. Cardita planicosta Heilprin, 1584, Contrib. Tert. Geol. and Pal., p. 87. Venericardia planicosta var. regia Harris, Amer. Jour. Sci., ser. ili, vol. xlvii, p. 302. Venericardia planicosta Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 5. Venericardia planicosta Clark, 1896, Bull. 141, U.S. Geol. Survey, p. 80, pl. xxi, fig. 3; pl. xxii, fig. 2; pl. xxiii, figs. la (?) 16 (?) Ic; pl. xxiv, figs. la (?) 16 (?) le; pl. xxv, figs. la—le. Description——The form originally described and figured by Conrad, which he subsequently called V. regia, seems to correspond very closely to the original V. planicosta of Europe. Conrad describes it as follows: “ Cordate; ribs about 22, broad and flattened, separated by a narrow groove which becomes obsolete at the base; ribs near the posterior end narrow, indistinct, and crossed by numerous strong wrinkles; lunule small; cordate, profoundly impressed; inner margin crenate.” Conrad, 1832. This form is the largest of our Eocene Venericardias and is widely distributed in and restricted to the Aquia formation. It.is readily dis- tinguished by its size, and its broad, flat ribs, which do not become obso- lete. Length, 110 mm.; width, 100 mm. Occurrence—AQuia ForMATION. Upper Marlboro, 1 mile west of Hardesty, Sheckels Farm near South River, 1 mile northeast of Piscat- away, Near Annapolis, Aquia Creek, Potomac Creek, Collington, Rolphs Landing, Mouth of Paspotansa Creek, Fredericktown (Cecil MARYLAND GEOLOGICAL SURVEY 179 County), Fort Washington, South River at mouth of Broad Creek, Severn River, Piscataway (Conrad’s original locality), 2 miles below Potomac Creek. Collections.—Maryland Geological Survey, Philadelphia Academy of Natural Sciences, Johns Hopkins University, U. 8. National Museum. VENERICARDIA MARYLANDICA 0. sp. Plate XL, Figs. 7, 7a. Description—Shell thin; outline circular; valves shallow; about 27 ribs, broad and flat on top, with deep, narrow interspaces near the beaks, but very flat, and separated by narrow, impressed: line toward the peri- phery. This species resembles very closely in outline V. pectuncularis from the Paris Basin. It is restricted to the Woodstock substage. Length, 80 mm.; width, 80 mm. Occurrence—NaNJEMOY Formation. 2 and 2$ miles above Popes Creek, Popes Creek, Woodstock. Collection Maryland Geological Survey. VENERICARDIA POTAPACOENSIS N. sp. Plate XL, Figs. 4, 5, 5a, 6, 6a. Description Shell small, very thick; valves relatively deep, and elon- gate along the line of the beak and posterior basal margin; beak an- teriorly situated; lines of growth strong; ribs 20 to 24 in number, ele- vated and crenulated toward the beak, and obsolete toward the periphery; lunule deeply impressed; muscular scars deeply impressed; margin strongly crenulate. This form is restricted to the Nanjemoy formation, and is most typically developed in the lower or Potapaco substage. Figure 4 repre- sents the typical Potapaco form, Figures 5 and 6 show the Woodstock form. Length, 40 mm.; width, 33 mm. Occurrence—N ANJEMOY FoRMATION. East and west of Port Tobacco, Popes Creek, Woodstock, $ mile below Chapel Point, Head of Nanjemoy 180 SYSTEMATIC PALEONTOLOGY Creek, Potomac Creek (50 feet from top of bluff), 1 mile southeast of Piscataway, La Plata, Upper Marlboro (gully southwest of town), 2 and 24 miles above Popes Creek. Collections—Maryland Geological Survey, U. 8. National Museum, Philadelphia Academy of Natural Sciences. Family CRASSATELLITIDAE. Genus CRASSATELLITES Kruger. CRASSATELLITES ALAEFORMIS (Conrad). Plate XLI, Figs. 1-8. Crassatella alaeformis Conrad, 1830, Jour. Acad. Nat. Sci. Phila., vol. vi, p. 228, joll, x ime I. Crassatella alaeformis Morton, 1834, Syn. Org. Rem. Cretaceous Group, App., p. 7. Crassatella capri-cranium Rogers, 1839, Trans. Am. Phil. Soc., new series, vol. vi, p. 375, pl. xxx, fig. 2. (Reprint: Geology of the Virginias, 1884, p. 672, pl. vy, fig. 2.) Crassatella alaeformis Conrad, 1846, Amer. Jour. Sci., ser. ii, vol. i, p. 396, pl. iii, fig. 3. (7) Crassatella palmula Conrad, 1846, Amer. Jour. Sci., ser. ii, vol. i, p. 396, pl. iv, fig. 1. Crassatella alaeformis H. C. Lea, 1848, Proc. Acad. Nat. Sci. Phila., vol. iv, p. 98. Crassatella capri-cranium H. C. Lea, 1848, Proc. Acad. Nat. Sci. Phila., vol. iv, p. 98. Crassatella alaeformis @Orbigny, 1850, Prodrome, vol. ii, p. 383. Crassatella capri-cranium Conrad, 1865, Amer. Jour. Conch., vol. i, p. 10. Crassatetla alaeformis Conrad, 1865, Amer. Jour. Conch., vol. i, p. 10. Crassatella alaeformis Conrad, 1866, Smith. Misc. Coll. (200), p. 5. Crassatella capri-cranium Conrad, 1866, Smith. Misc. Coll. (200), p. 5. Crassatella declivis Heilprin, 1880, Proc. U. 8. Nat. Museum, vol. ili, pp. 151, 152, pl. facing p. 150, fig. 9. Crassatella protexta de Gregorio, 1890, Ann. Géol. et Pal., pl. xxv, fig. 12. Crassatella alaeformis Clark, 1895, Johns Hopkins Uniy. Cire., vol. xv, p. 5. Crassatella alaeformis Clark, 1896, Buil. 141, U. 8. Geol. Survey, p. 81, pl. xxvii, figs. la—-Lk. (7) Crassatella palmula Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 93. Crassatella declivis Aldrich, 1897, Bull. Amer. Pal. No. 8, p. 4, pl. iii, figs. 1, la. Description Shell transversely ovate oblong; anterior side ros- trated; posterior side short and rounded; umbones transversely sulcated; margin slightly crenulated within.” Conrad, 1830. The variations in C. alaeformis Conrad are so great that in the ab- sence of connecting forms one would be led to consider the existence of several well-defined species. After a careful study of a large amount of MARYLAND GEOLOGICAL SURVEY 181 material belonging to this important species, it appears that the forms figured and described by Rogers and Heilprin as distinct species are only varieties of Conrad’s C. alaeformis. The species is largely represented in the lower portion of the Middle Atlantic Coast series, especially in the Piscataway substage of the Aquia formation. It is rarer in the Pas- potansa substage, and here two distinct forms are found, each different from the older forms. The specimens from the sandy beds along the Potomac are small and very elongate, the average size being 40 x 20 mm. The indurated ledge at Upper Marlboro, Hardesty, South River bridge, and Rolphs Landing contains a very large form at the other end of the alaeformis series. This reaches the size and proportions of 90 x 60 mm., but a single specimen from South River, which may however belong to another species, attains the size of 95x80 mm. The larger elongate forms approach the several Miocene species in size and outline. The specimens from the various beds of the Piscataway substage vary greatly in size and form and connect the Paspotansa varieties with each other and almost connect them with C. aquiana. C. palmula Conrad prob- ably belongs in this series. Length, 40 to 90 mm.; height, 20 to 60 mm. Occurrence—AQuia Formation. Paspotansa Creek, 2 miles below Potomac Creek, Potomac Creek, 1 mile southeast of Mason Springs, Clif ton Beach, Glymont, Mattawoman Creek, Liverpoo] Point, Wades Bay, Aquia Creek, 1 mile northeast of Piscataway, Brooks Estate near Seat Pleasant, Fort Washington, Upper Marlboro, 3 miles west of Leeland on Western Branch, West of Collington, between Buena Vista and Colling- ton, Sheckel’s Farm near South River, Rolphs Landing. Collections —Maryland Geological Survey, Johns Hopkins University, U. 8. National Museum, Philadelphia Academy of Natural Sciences. CRASSATELLITES AQUIANA (Clark). Plate XLII, Figs. 1, 2a, 2b. Orassatella aquiana Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 5. Crassatella aquiana Clark, 1896, Bull. 141, U. S. Geol. Survey, p. 82, pl. xxvi, figs. 2a—2e. Description.—* Shell moderately large, attenuated posteriorly; surface with a few broad, shallow, concentric furrows, indicating periods of 182 SYSTEMATIC PALEONTOLOGY growth, and fine concentric lines, often obscure; lunules broad, deeply — depressed. “This species differs from 0. alaeformis by its shorter, broader pos- terior extremity; by the absence of deep, prominent furrows on the um- bones, and by the umbones themselves being higher.” Clark, 1896. This species shows considerable variation in size and form, sometimes approaching the more elevate varieties of C. alaeformis. On the other hand it frequently becomes so short and elevate as to approach Astarte in outline. This species is most abundant in the Piscataway substage. Length, 60 mm.; height, 50 mm. Occurrence—AQuiA ForMATION. Aquia Creek, Glymont, Reedy Run, Brooks Estate near Seat Pleasant, Potomac Creek, Liverpool Point, Mat- tawoman Creek. Collections—Maryland Geological Survey, Johns Hopkins University, Philadelphia Academy of Natural Sciences. CRASSATELLITES ALTA (Conrad). Plate XLII, Fig. 3. Crassatella alta Conrad, 1832, Fossil Shells of the Tertiary, No. 2, p. 21, pl. vii. Crassatella alta Conrad, 1835, Trans. Geol. Soc. Penn., vol. i, p. 335. Description.—* Suboval, thick and ponderous, compressed; anterior margin obtusely rounded; posterior margin broad and slightly angular; beaks with regular concentric grooves, and somewhat angulated behind; inner margin crenulated.” Conrad, 1832. Conrad recorded this species from Upper Marlboro in 1835, but there is no other evidence of its occurrence at that locality. The large speci- men here figured is from Hardesty and can belong to no other known species. The large forms alluded to under C. alaeformis may be the same as the Upper Marlboro forms which Conrad referred to C. alta. Length (of fragment), 105 mm.; width, 75 mm. Occurrence—AQuIA Formation. Hardesty. Collection —Maryland Geological Survey. MARYLAND GEOLOGICAL SURVEY 183 CRASSATELLITES sp. Plate XLII, Figs. 4, 4a. The specimen figured possesses characters very different from any other known species of the genus and if normal must be new, although it is perhaps only a diseased specimen of C. alaeformis. Length, 20 mm.; width, 13 mm. Occurrence—AQuia Formation. Clifton Beach. Collection —Johns Hopkins University. Family ASTARTIDAE. Genus ASTARTE Sowerby. ASTARTE MARYLANDICA Clark. Plate XLII, Fig. 5. Astarte marylandica Clark, 1895, Johns Hopkins Univ. Circ., vol. xv, p. 5. Astarte marylandica Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 80, pl. xxi, fig. 2. Description —* Shell small, roundedly trigonal, somewhat compressed, thick, nearly equilateral; surface concentrically costated and with super- imposed fine striae; umbones prominent.” Clark, 1896. Length, 16 mm.; width, 15 mm. Occurrence.—AQuiaA Formation. Upper Marlboro, Brooks Estate near Seat Pleasant, Sheckel’s Farm near South River. Collections—Johns Hopkins University, Maryland Geological Survey. Family PLEUROPHORIDAE. Genus CORALLIOPHAGA Blainville. Subgenus ORYCTOMYA Dall. CoRALLIOPHAGA (ORYCTOMYA) BRYANT Clark. Plate XLII, Figs. 1, la, 2, 2a. Coralliophaga bryani Clark, 1895, Johns Hopkins Univ. Circ., vol. xv, p. 5. Coralliophaga bryani Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 73, pl. xv, figs. 2a, 2b. Description.—* Shell transversely oblong, thin, slightly gaping pos- teriorly; prominent fold from umbo to lower margin; surface with deli- 184 SYSTEMATIC PALEONTOLOGY cate lines of growth and fine radial rows of minute granules, obsolete ~ over much of the surface ; teeth consisting of two small cardinal and one long posterior lateral; pallial line with shallow sinus.” Clark, 1896. Only two specimens, both right valves, have been found. The one here newly figured is smaller than the type, but more nearly perfect. The teeth are not well preserved, but the radiating rows of granules show the generic affinities. ‘ Length, 20 mm.; height, 16 mm. Occurrence—AQuia ForMATION. 1 mile southeast of Mason Springs, Pomonkey Neck. Collections —Maryland Geological Survey, U. 8. National Museum. Order ANOMALODESMACEA. Family PERIPLOMIDAE. - Genus PERIPLOMA Schumacher. PERIPLOMA (?) sp. Two specimens have been found which have the general form of this genus, but are too imperfect for complete identification or description. Length, 29 mm.; height, 24 mm. Occurrence.—N ANJEMOY Formation. East of Port Tobacco, Wood- stock. Collections—Maryland Geological Survey, Philadelphia Academy of Natural Sciences (No. 6430). Family PHOLADOMYIDAE. Genus PHOLADOMYA Sowerby. PHOLADOMYA MARYLANDICA Conrad. Plate XLII, Fig. 3. Pholadomya marylandica Conrad, 1842, Proc. Nat. Inst. Bull. ii, p. 193, pl. i, fig. 3. Pholadomya marylandica Conrad, 1846, Amer. Jour. Sci., ser. ii, vol. i, p. 214, joule, Til, vata, 2). Pholadomya marylandica H.C. Lea, 1848, Proc. Acad. Nat. Sci. Phila., vol. iv, p. 104. Pholadomya marylandica Conrad, 1865, Amer. Jour. Conch., vol. i, p. 8. Pholadomya marglandica Conrad, 1866, Smith. Mise. Coll. (200), p. 8. Pholadomya marylandica Clark, 1895, Johns Hopkins Uniy. Cire., vol. xv, p. 5. Pholadomya marylandica Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 75, pl. xxix, fig. 2. MARYLAND GROLOGICAL SURVEY 185 Description.—* Ovate, profoundly ventricose, with coarse, irregular concentric lines and furrows, and obsolete, rather distant, radii; sum- mit of umbo prominent.” Conrad, 1842. The very fragile shell of this species was found only partially pre- served in a few instances, although numerous casts were obtained from the indurated layer, Zone 5, at Aquia Creek. Length, 75 mm.; height, 55 mm. Occurrence—AQuia Formation. Clifton Beach (upper indurated bed), Aquia Creek, Fort Washington, Piscataway (Conrad). Collections—Maryland Geological Survey, Philadelphia Academy of Natural Sciences, Johns Hopkins University, U. $8. National Museum. Order PRIONODESMACEA. Family MYTILIDAE. Genus MODIOLUS Lamarck. MopioLus ALABAMENS!IS Aldrich. Plate XLIII, Figs. 4, 5, 5a. Modiola alabamensis Aldrich, 1895, Bull. Amer. Pal. No. 2, p. 16, pl. v, fig. 13. Modiola potomacensis Clark, 1895, Johns Hopkins Uniy. Circ., vol. xv, p. 5. Modiola potomacensis Clark, 1896, Bull. 141, U.S. Geol. Survey, p. 85, pl. xxxiv, figs. la—le. - Modiolus (Brachydontes) potomacensis Dall, 1898, Trans. Wagner Free Inst. Sci., vol. iii, pt. iii, p. 796. Description.—* Shell strongly arcuate, surface with raised lines closely set, becoming nearly obsolete on the beaks; a few lines of growth cross- ing the striae; beak small, hinge margin slightly curved, ascending; very small fissure on basal margin.” Aldrich, 1895. Shell small, oblong, thin, tumid, anterior side somewhat contracted: surface with fine costated striae nearly obsolete anteriorly and _ less strongly accentuated posteriorly than in the center, crossed occasionally by irregular lines of growth; umbones prominent, curved. Length, 32 mm.; width, 15 mm. Occurrence—NANJEMOY ForMATION. Popes Creek, Woodstock, 24 miles above Popes Creek. Aqguia Formation. Liverpool Point, Clif- 186 SYSTEMATIC PALEONTOLOGY ton Beach, Wades Bay, Aquia Creek (Zones 2 and 3), Potomac Creek, 2 miles below Potomac Creek, Glymont, 1 mile southeast of Mason Springs, Upper Marlboro, Fort Washington, Mouth of Paspotansa Creek. Collections —Maryland Geological Survey, Johns Hopkins University, U. S. National Museum, Philadelphia Academy of Natural Sciences. MoDIOLUS MARYLANDICUS Na. sp. Plate XLIII, Fig. 6. Description.—Shell thin and fragile; beaks elevated, strongly incurved, and situated far back of the anterior extremity; surface marked by strong lines of growth and faint radiating lines, developing into strong radial cracks. One specimen only, and that showing parts of both valves, has been found; while another that may belong to this species, although it shows some quite different characteristics, was also obtained. Length (of fragment), 20 mm.; width, 10 mm. Occurrence.—NANsEMOY FoRMATION. Woodstock. Collection.—Maryland Geological Survey. Genus LITHOPHAGA Bolten. LITHOPHAGA MARYLANDICA N. sp. Plate XM, Bis. 7. Solemya petricoloides Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 5. Solemya petricoloides Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 74. Not Byssomya petricoloides Lea. Description.—* Shell elongated, very inequilateral, slightly gaping, thin; surface nearly smooth with fine lines of growth; umbones very posteriorly situated; hinge edentulous; pallial line obscure.” Clark, 1896. Our specimens differ from petricoloides in having the beaks nearly terminal. Length, 11 mm.; width, 4.5 mm. Occurrence.—AgQuta FormMATION. Clifton Beach. Collections —Maryland Geological Survey, Johns Hopkins University. q ‘ i ; a 5 4: MARYLAND GEOLOGICAL SURVEY 187 Family ANOMIIDAE. Genus ANOMIA Miller. ANOMIA MARYLANDICA nN. sp. Plate XLIV, Figs. 2, 2a, 3. Description.—Shell small, thin, irregular; valves very unequal; right valve moderately and uniformly convex; byssal opening small; left valve very convex and irregular. Beak anteriorly situated and much in- curved. Surface marked by fine raised radiating threads and irregular wavy concentric undulations. Lines of growth strong, irregular. Length, 19.5 mm.; height, 18 mm. Occurrence—NANJEMOY ForMATION. Woodstock, Popes Creek. Aquria Formation. Clifton Beach. Collection —Maryland Geological Survey. ANOMIA McGEEI Clark. Plate XLIV, Figs. 1, 1a. (?) Anomia ruffini Conrad, 1855, Fossils Medial Tertiary, p. 74, pl. xlii, fig. 6. Anomia megeei Clark, 1895, Johns Hopkins Univ. Circ., vol. xv, p. 5. Anomia megeei Clark, 1896, Bull. 141, U.S. Geol. Survey, p. 86, pl. xxxiv, figs. 5a, 5d. (?) Anomia ruffini Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 95. Anomia ruffint Dall, 1898, Trans. Wagner Free Inst. Sci., vol. ili, pt. iv, p. 782. (In part). Description.—* Shell of left valve rather solid, convex, nearly equi- lateral; surface strongly lamellar, with faint radial plaits, stronger in the latter than in the earlier portions of the shell.” Clark, 1896. The type of this species, which is the only adult specimen known, was found in the collections of the Philadelphia Academy of Natural Sciences labelled “ Eocene of Hanover County, Va.” Anomia ruffini Conrad was described with Miocene fossils (the type having been found on the Pamunkey River, Virginia, where both Eocene and Miocene strata occur), and, was later, by Conrad and by others, placed in lists of both Eocene and Miocene forms. It is extremely doubtful if the species has ever been found in the Eocene. The resemblance between A. mcgeei and A. ruffini is so close and both are so different from any other forms which have ever been found 188 SYSTEMATIC PALEONTOLOGY in the Eocene that it is possible that they both represent the same Miocene species. Dr. Dall considers them identical but is in doubt as to the horizon from which they came. It seems best to publish here the original figures of A. megeei under the original name in order to bring the question before the eyes of future investigators. Length, 50 mm.; height, 48 mm. Occurrence.—Hanover County, Va. Collection.—Philadelphia Academy of Natural Sciences. Family PECTINIDAE. Genus PECTEN Miller. PECTEN CHOCTAVENSIS Aldrich. Plate XLIV, Figs. 4, 5, 6. Pecten choctavensis Aldrich, 1895, Bull. Amer. Pal. No. 2, p. 16, pl. v, fig. 7. Description.—*‘ Shell suborbicular thin, depressed, finely closely rib- bed, ribs showing through the substance of the shell, imbricated near the ventral margin and on the anterior slope; ears ribbed and ribs im- bricated with fine oblique reticulations between.” Aldrich, 1895. There are 40 to 50 ribs, which are lamellated, especially when old, but sometimes when very young. The young shells from Alabama do not show any lamellation. The ribs increase both by bifurcation and intercolation. Camptonectes structure is a constant characteristic. Width, 23 mm.; height, 24 mm. Occurrence—NANJEMOY ForMATION. Popes Creek, 14 miles above Popes Creek. Aguia Formation. Upper Marlboro, 1 mile northeast of Piscataway, South East Creek (1 mile from Chester River). Collection —Maryland Geological Survey. PECTEN DALLI Clark. Plates nL Vs) Riese) Va, be Pecten rogersi Clark, 1895, Johns Hopkins Univ. Cire., vol. xy, p. 5. Pecten rogersi Clark, 1896, Bull. 141, U.S. Geol. Survey, p. 85, pl. XXXiv, figs. 2a-2e. Pecten dalli Clark, 1898, Johns Hopkins Univ. Cire., vol. xviii, p. 18. Pecten (Pseundamusium) frontalis Dall, 1898, Trans. Wagner Free Inst. Sei., vol. iii, Pt. lv, Pp. Tos. Not Pecten rogersi Conrad. MARYLAND GEOLOGICAL SURVEY 189 Description.—* Shell small, orbicular, subpellucid, nearly equilateral, thin; surface shining with fine, delicate concentric lines and rather ob- scure, in places obsolete, radial ribs that show most strongly near the anterior margins; umbones approximate and acute; auricles very un- equal and costated.” Clark, 1896. This very beautiful species shows some points of similarity to P. cal- valus Conrad in form and surface features, but the radial striae are lack- ing upon the latter. It differs from P. choctavensis in its feebler sculp- ture. It possesses a faint camptonectes structure. Width, 16 mm.; height, 18 mm. Occurrence—NAaNJEMOY Formation. Woodstock, Upper Marlboro (deep cut near Chesapeake Beach R. R. station). Aguia Forma- TION. Potomac Creek, South East Creek (1 mile above Chester River). Collections—Johns Hopkins University, Maryland Geological Survey. PECTEN JOHNSONI Clark. Plate XLIV, Figs. 8, 8a. Pecten johnsoni Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 5. Pecten johnsoni Clark, 1896, Bull. 141, U.S. Geol. Survey, p. $5, pl. xxxiy, figs. da, 3b. Description. Shell small, suborbicular, equilateral; surface with about twenty uniform, distant, rounded costate, separated by broad interspaces, with a few short costae at basal margin, the whole crossed by fine lines of growth; ears prominent, unequal.” Clark, 1896. P. greggi Harris resembles this form very closely. It differs in hav- ing stronger camptonectes structure, and in not having the number of ribs increase toward the periphery. Width, 14 mm.; height, 15 mm. Occurrence—NANJEMOY FoRMATION. Woodstock. Agura ForMa- TION. 2 miles below Potomac Creek, Potomac Creek, Mouth of Paspo- tansa Creek. Collections —Johns Hopkins University, Maryland Geological Survey. 190 SYSTEMATIC PALEONTOLOGY PECTEN sp. Plate XLIV, Figs. 9, 9a. Pecten sp. Clark, 1895, Johns Hopkins Univ. Circe., vol. xv, p. 5. Pecten sp. Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 86, pl. xxxiv, fig. 4. Description.—*< Shell small, orbicular; surface with about twenty broad, flat costae, dividing in most cases in passing downward, so that over thirty appear at the margin; umbones compressed; ears unequal.” Clark, 1896. This differs from P. johnsoni only in having the ribs increase by bifureation instead of intercolation, and in having the ribs broader than the interspaces. As the figured specimen is the only one that has been found and is very immature it is best not to give ita name. Perhaps it is an aberrant or immature form of P. johnson, or of P. wahtubbeanus Dall. Width, 10 mm.; height, 11 mm. Occurrence—AQuia ForMATION. Potomac Creek. Collection —Maryland Geological Survey. Family OSTREIDAE. Genus OSTREA Linné. OSTREA COMPRESSIROSTRA Say. Plates XLV, XLVI, XLVII. Ostrea conpressirostra Say, 1824, Jour. Acad. Nat. Sci. Phila., vol. iv, p. 182, pl. viii, figs. 2a, 2b [Reprint Bull. Amer. Pal. No. 5, p. 88, pl. viii, figs. 2a, 20.] Ostrea compressirostra Morton, 1834, Syn. Org. Rem. Cretaceous Group, App., p. 2. Ostrea sinuosa Rogers, 18387, Trans. Amer. Philos. Soc., vol. v, p. 340; vol. vi, pl. xxvii, fig. 1. Ostrea compressirostra H. C. Lea, 1848, Proc. Acad. Nat. Sci. Phila., vol. iv, p. 103. Ostrea bellovacina Conrad, 1842, Proc. Nat. Inst,, Bull. ii, p. 172 (not of Lamarck). Ostrea sinuosa H. C. Lea, 1848, Proc. Acad. Nat. Sci. Phila., vol. iv, p. 103. Ostrea compressirostra Conrad, 1865, Amer. Jour. Conch., vol. i, p. 15. Ostrea sinuosa Conrad, 1865, Amer. Jour. Conch., vol. i, p. 15. Ostrea compressirostra Conrad, 1866, Smith. Misc. Coll. (200), p. 3. Ostrea compressirostra Heilprin, 18838, White’s Fossil Ostreidae; Fourth Ann. Rept. U. 8. Geol. Survey, p. 309, pl. lxy, figs. 1, 2. Ostrea compressirostra Heilprin, 1884, Contrib. Tert. Geol. and Pal., p. 85. Ostrea sinuosa Rogers, 1884, Geology of the Virginias, p. 668, pl. ii, fig. 1. Ostrea compressirostra de Gregorio, 1890, Ann. Géol. et Pal., t. ii, p. 177, pl. xx, figs. 1, 8. MARYLAND GEOLOGICAL SURVEY 191 Ostrea compressirosira Harris, 1894, Amer. Jour, Sci., ser. ili, vol. xlvii, p. 302. Ostrea compressirostra Clark, 1895, Johns Hopkins Uniy. Cire., vol. xv, p. 5. Ostrea compressirostra Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 86, pl. xxxvii, figs. 1, 2a-2c; pl. xxxvili, figs. 1a, 1b, 2a—2c; pl. xxxix, figs. 1, 2a, 2b: pl. x1, fig. 1. Ostrea compressirostra Dall, 1898, Trans. Wagner Free Inst. Sci., vol. iii, pt. iv, p. 679. Description —* Shell sinistral, subovate: inferior valve convex, with numerous convex ribs interrupted by fornicated scales at the lines of increment; /inge curving a little upward, very much contracted and short: superior valve flat, wrinkled concentrically, without any appear- ance of longitudinal lines: hinge more dilated than that of the superior valve, and oblique with respect to the thickness of the shell.” Say, 1824. This is one of the most abundant fossils in the Aquia formation. The Nanjemoy formation contains many small oysters which are probably the young of sellaeformis, although they cannot be distinguished from the young of this species. Length, 215 mm.; width, 180 mm. Occurrence—AQuia Formation. Upper Marlboro, Hardesty, Aquia Creek, Brooks Estate near Seat Pleasant, 3 miles west of Leeland on Western Branch, Sheckel’s Farm near South River, Reedy Run, Liver- pool Point, 14 miles south of Grimesville, Potomac Creek, Fort Wash- ington, Tinkers Creek, 1 mile northeast of Piscataway, Swan Creek (ravine near Piscataway Creek), 1 mile southeast of Mason Springs, Mouth of Paspotansa Creek, Wades Bay, 3 miles west of Pisgah, Clifton Beach, Mattawoman Creek, 2 miles south of South River, Glymont, 2 miles below Potomac Creek, Leeland, Seven River. Collections —Maryland Geological Survey, Johns Hopkins University, U. S. National Museum, Philadelphia Academy of Natural Sciences. OSTREA COMPRESSIROSTRA VAR. ALEPIDOTA Dall. Ostrea compressirostra var. alepidota Dall, 1898, Trans. Wagner Free Inst. Sci., vol. iii, partiv, p. 680. Description.—* Without raised lamellae externally but with radial erooves.” Dall, 1898. 192 SYSTEMATIC PALEONTOLOGY Shell small, roughly triangular; beak high, in some cases shghtly twisted; raised lamellae absent or confined to the extreme periphery; radial grooves, becoming stronger toward the periphery. Length, 85 mm.; width, 65 mm. Occurrence—AQquia Formation. Fort Washington, Aquia Creek. Collections —Maryland Geological Survey, U. 8. National Museum, Philadelphia Academy of Natural Sciences. OSTREA SELLAEFORMIS Conrad. Plates XLVIII, XLIX. Ostrea sellaeformis CORTE, 1832, Fossil Shells of the Tertiary, No. 2, p. 27, pl. xili, fig. 2. Ostrea sellaeformis Morton, 1834, Syn. Org. Rem. Cretaceous Group, App., p. 6. Ostrea sellaeformis Conrad, 1842, Proc. Nat. Inst., Bull. ii, pp. 192, 195, pl. i, fig. 1. Ostrea sellaeformis H. C. Lea, 1848, Proc. Acad. } Nat. Sci. Phila., vol. iv, p. 103. Ostrea sellaeformis Conrad, 1865, Amer. Jour. Conch., vol. i, p. 15. Ostrea sellaeformis Conrad, Smith. Misc. Coll. (200), p. 3. Ostrea sellaeformis Heilprin, 1883, White’s Fossil Ostreidae; Fourth Ann. Rept. U.S. Geol. Survey, p. 311, pl. lxii, figs. 1, 2; pl. lxiii, fig. 1. Ostrea seliaeformis Clark, 1895, Johns Hopkins Univ. Circ., vol. xv, p. 5. Ostrea sellaeformis Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 87, pl. xxxy, figs. Valais ip lexcxcxay inet O Saul lO Description. Oblong, convex, thick and ponderous, lobed; one side of the larger valve profoundly sinuous and the opposite side gibbous; smaller valve sinuous and little convex; dorsal margin long and slightly arched, with both extremities obtusely rounded.” Conrad, 1833. This form although very abundantly and characteristically developed in the valleys of the James and Pamunkey rivers, occurs generally in the Potomac Valley and farther north only as small specimens, almost indistinguishable from the young of O. compressirostra. Height, 60 mm.; width, 40 mm. (largest Maryland specimen). Occurrence-—N ANJEMOY ForMATION. Popes Creek, 14 miles above Popes Creek, 2$ miles above Popes Creek, East of Port Tobacco, Upper Marlboro (deep cut near Chesapeake Beach R. R. station), Woodstock. Collections —Johns Hopkins University, Philadelphia Academy of Natural Sciences, Maryland Geological Survey. MARYLAND GEOLOGICAL SURVEY 193 Subgenus GRYPHAEOSTREA Conrad. OstREA (GRYPHAEOSTREA) VOMER (Morton). Plate L, Figs. 1, la, 1b, 2, 3, 4, 4a, 5. Gryphaea vomer Morton, 1830, Jour. Acad. Nat. Sci. Phila., vol. vi (1st series), p. 83. Gryphaea vomer Morton, 1834, Syn. Org. Rem. Cretaceous, p, 54, pl. ix, fig. 5. Gryphaea vomer Conrad, 1855, Trans. Geol. Soc. Penn., vol. i, p. 336. Gryphaea vomer Conrad, 1842, Proc. Nat. Inst., Bull. ii, p. 172. Ostrea (Gryphacostrea) subeversa Conrad, 1865, Amer. Jour. Conch., vol. i, p. 15 (name only). Ostrea sp. Clark, 1895, Johns Hopkins Uniy. Cire., vol. xy, p. 6. Ostrea sp. Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 88, pl. xxxix, figs. 3a—8c. Ostrea subeversa Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 93. Ostrea (Gryphaeostrea) subeversa Dall, 1898, Trans. Wagner Free Inst. Sci., vol. iii, pt. iv, p. 681. Description.—* Oblong-oval, thin, narrow; lower valve deep, longi- tudinally curved; beak prominent, curved laterally; upper valve small in proportion to the lower, and marked with distinct, concentric, squamose plates.” Morton, 1834. The possible equivalence of this form with Gryphaea vomer Morton, or Gryphaea eversa Mellville was suggested by Dall. Conrad recorded the species from Piscataway and Upper Marlboro. Length, 39 mm.; width, 20 mm.; depth of lower valve, 10 mm. Occurrence.—NANJEMOY Formation. 4 mile below Chapel Point. Aquia Formation. Piscataway, Upper Marlboro, Aquia Creek, Po- tomac Creek, 2 miles below Potomac Creek, Sheckel’s Farm near South River, Fredericktown, Glymont. Collections.—Maryland Geological Survey, Johns Hopkins University, Philadelphia Academy of Natural Sciences. Genus GRYPHAEA Lamarck. GRYPHAEA VESICULARIS Lamarck. Plate L, Figs. 6, Ga. Gryphaea vesicularis Lamarck, 1806, Ann. Mus. vili, p. 160, pl. xxii, fig. 3. An. Sans. Vert., vol. vi, p.-209. A single specimen of this form was found associated with Eocene fossils at Clifton Beach. It is very perfect, having both valves in posi- tion. It seems hardly possible, however, that it can be a representative 13 194 SYSTEMATIC PALEONTOLOGY of the Eocene fauna, as an isolated specimen of this typical Cretaceous species, it seems more probable that it must have been derived from Cretaceous deposits. An even more remarkable occurrence is the dis- covery of many specimens of Terebratula harlant under similar condi- tions (see p. 204). Occurrence.—AQUIA FoRMATION. Clifton Beach. Collection —Maryland Geological Survey. Family PTERIIDAE. Genus PTERIA Scapoli. PTERIA LIMULA (Conrad). Plate 11, Tes at Avicula limula Conrad, 1833, Fossil Shells of the Tertiary, No. 4, p. 39. Description —* Shell convex, with slight concentric undulations; umbo tapering gradually towards the apex, which is acute, but not prominent; wings large and very oblique; sinus of the posterior margin not profound; nacre very pearly and iridescent. Height, 14 inches.” Conrad, 1833. Height of largest fragment, 18 mm. Occurrence—NANJEMOY Formation. Popes Creek, Hills Bridge. Aquia Formation. Upper Marlboro. 3 Collection Maryland Geological Survey. Family ARCIDAE. Genus GLYCYMERIS Da Costa. +LYCYMERIS IDONEUS (Conrad). Plate LI, Figs. 2, 2a, 3, 3a, 4. Pectunculus idoneus Conrad, 1833, Fossil Shells of the Tertiary, No. 4, p. 39. Pectunculus idoneus Clark, 1895, Johns Hopkins Univ. Circ., vol. xv, p. 5. Pectunculus idoneus Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 84, pl. xxix, figs. la-le, 2. Description. Shell suborbicular, thick, convex; oblique, with rather obscure radiating striae, and very minute, intervening lines; umbo con- ' vex; beaks distant, rather prominent and pointed; cardinal teeth large; ee ae — ee MARYLAND GEOLOGICAL SURVEY 195 truncated in the center by a rectilinear line; cavity capacious; margin crenate. Length, 14 in.” Conrad, 1833. Shell moderately thick, obliquely orbicular, rather ventricose, slightly inequilateral, equivalve, with faint radiations; hinge with few promi- nent teeth; margins crenulated; beaks depressed. The higher beds of the Aquia formation, especially the indurated ledge at Upper Marlboro and at the localities to the northeast, are very rich in shells of Glycymeris. Although in some features they at times show slight variations from G. idoneus of the Gulf, the differences are too slight to warrant specific distinction. Length, 60 mm.; height, 60 mm. Occurrence—NANJEMOY ForMATION. 3 miles above Popes Creek, Woodstock. Aguia Formation. Upper Marlboro, 1 mile west of Hardesty, Potomac Creek, 1 mile northeast of Piscataway, Hardesty, Sheckels Farm near South River, 2 and 3 miles south of South River, Rolph’s Landing. Collections.—Philadelphia Academy of Natural Sciences, Johns Hop- kins University, Maryland Geological Survey. Family LIMOPSIDAE. Genus TRIGONOARCA Conrad. TRIGONOARCA DECISA (Conrad) VAR. Plate LI, Figs. 5, 5a. Pectunculus decisus Conrad, 1833, Fossil Shells of the Tertiary, p. 39. Limopsis decisus Conrad, 1860, Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. iy, p. 297, pl. xlvii, fig. 13. (7) Noetia pulchra Gabb, 1860, Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. iv, p. 388, pl. Ixvil, fig. 65. Trigonoarca pulchra var. Harris, 1897, Bull. Amer. Pal. No. 9, p. 48, pl. viii, figs. 2, 2a. Description—* Shell longitudinally suboval, equilateral, with obsolete radiating striae; posterior end obliquely truncated, umbonial slope angu- lated, incurved; beaks small, pointed and recurved; cardinal teeth small and crowded; series not much arcuated; margin entire. Length, 4 of an inch.” Conrad, 1833. This form is smaller and proportionally longer than T. pulchra Gabb 196 SYSTEMATIC PALEONTOLOGY and has fainter sculpture. It is much more like the variety figured by Harris. Length, 4 mm.; width, 2.5 mm. Occurrence—N ANJEMOY ForMATION. Woodstock. Collection Maryland Geological Survey. Family PARALLELODONTIDAE. Genus CUCULLAEA Lamarck. CUCULLAEA GIGANTEA Conrad. Plates LII, LI, LIV, LV. Cucullaea gigantea Conrad, 1830, Jour. Acad. Nat. Sci. Phila., vol. vi, p. 227, pl. x, fig. 4. Cucullaea onochela Rogers, 1839, Trans. Amer. Philos. Soc., vol. vi, p. 372, pl. XXvlii, fig. 2. Cucullaea transversa Rogers, 18359, Trans. Amer. Philos. Soc., vol. vi, p. 373, pl. SOxIbx, wileR, IL. Cucullaea gigantea H. C. Lea, 1848, Proc. Acad. Nat. Sci. Phila., vol. iv, p. 98. Cucullaea onochela H. C. Lea, 1848, Proc. Acad. Nat. Sci. Phila., vol. iv, p. 98. Cucullaea transversa H. C. Lea, 1848, Proc. Acad. Nat. Sci. Phila., vol. iv, p. 98. Cucullaea rogersiana Nyst, 1848, Tabl. Synopt. Arcacées, p. 63. Latiarca gigantea Conrad, 1865, Amer. Jour. Conch., vol. i, p. 11. Latiarca onochela Conrad, 1865, Amer. Jour. Conch., vol. 1, p. 11. Latiarca transversa Conrad, 1865, Amer. Jour. Conch., vol. i, p. 11. Latiarca gigantea Conrad, 1866, Smith. Misc. Coll. (200), p. 4. Latiarca onochela Conrad, 1866, Smith. Mise. Coll. (200), p. 4. Latiarca transversa Conrad, 1866, Smith. Misc. Coll. (200), p. 4. Latiarca idonea Conrad, 1872, Proc. Acad. Nat. Sci. Phila., p. 53, pl. ii, fig. 1. Arca rogersi Heilprin, 1881, Proc. Acad. Nat. Sci. Phila., p. 449. Cucullaea onochela Rogers, 1884, Geology of the Virginias, p. 669, pl. ili, fig. 2. Cucullaca transversa Rogers, 1884, Geology of the Virginias, p. 670, pl. iv, tig. 1. Arca onochela Heilprin, 1884, Contrib. Tert. Geol. and Pal., p. 87. Cucullaea transversa Harris, 1894, Amer. Jour. Sci., ser. ili, vol. xlvii, p. 302. Cucullaea gigantea Clark, 1895, Johns Hopkins Uniy. Circ., vol. xv, p. 5. Cucullaea gigantea Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 84, pl. xxx, xxxi, SORTA) SOON Cucullaea gigantea var. Harris, 1897, Bull. Amer. Pal. No. 9, p. 49, pl. viii, figs. 3a, 4. Cucullaea gigantea Dall, 1898, Trans. Wagner Free Inst. Sci., vol. iii, pt. iv, p. 603. Cucullaea transversa Dall, 1898, Trans. Wagner Free Inst. Sci., vol. iii, pt. iv, pp. 603, 646. Description—* Shell subtriangular, obliquely cordate; very ventri- ‘cose, with numerous longitudinal sulci; anterior side flattened, produced ee a a a MARYLAND GEOLOGICAL SURVEY 197 and subeuneiform; posterior side very short; umbones gibbous; beaks distant and much inecurved.” Conrad, 1830. A careful examination of the various forms of Cucullaea from the Maryland and Virginia Eocene shows them to be modifications of a single species that possesses great variability in outline and surface decoration. The most profound changes appear upon comparison of young and adult forms. The immature shells are relatively not as high or as tumid and possess much narrower ligament areas than the adults. Rogers gave the name of C. lransversa to these young forms. Casts of the larger shells are not uncommon and are locally known as “ turtle heads.” Professor Harris agrees with us in regarding the Maryland-Virginia Cucullaeas as all of one species, and also includes in it a form from the Chickasawan of Alabama of the transversa type. Dr. Dall, however, recognizes two species. If it were possible to separate the forms the dis- tinction between the gigantea and transversa types would be very useful, since the former occurs only in the Aquia formation, while the latter is the only form found in the Nanjemoy formation or in the Gulf states. Occurrence—NANJEMOY Formation. Popes Creek, Woodstock, Thrift (well). Agura Formation. Liverpool Point, 1 mile southeast of Mason Springs, Potomac Creek, Paspotansa Creek, 2 miles below Po- tomac Creek, Aquia Creek, Clifton Beach, 1 mile northeast of Piscata- way, Upper Marlboro, Hardesty, Rolph’s Landing, 3 miles west of Leeland, Fort Washingtcn, Glymont, Sheckel’s Farm near South River, Fredericktown (?). Collections——Maryland Geological Survey, Johns Hopkins University, U.S. National Museum, Philadelphia Academy of Natural Sciences. LEDA PARVA (Rogers). Plate LVI, Figs. 5, 6, 7, 7a. Nucula parva Rogers, 1837, Trans. Amer. Philos. Soc., vol. v, p. 340. (Reprint Geology of the Virginias, 1884, p. 668.) Nucula parva H. C. Lea, 1848, Proc. Acad. Nat. Sci., Phila., vol. iv, p. 102. Leda parva Conrad, 1854, Proc. Acad. Nat. Sci. Phila., vol. vii, p. 29. Nuculana parva Conrad, 1865, Amer. Jour. Conch., vol. i, p. 3. Nuculana parva Conrad, 1866, Smith. Mise. Coll. (200), p. 3. Leda parva Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 5. Leda parva Clark, 1896, Bull. 141, U. S. Geol. Survey, p. 83, pl. xxvili, figs. 2a—2d 198 SYSTEMATIC PALEONTOLOGY Description.—* Shell ovate, inflated, rounded before, not much pro- duced, but rapidly tapering to a truncated point behind, furnished with about twelve rather coarse concentric folds or ridges, and a longitudinal gently depressed groove or undulation of surface, running from near the beak to the posterior basal margin; beaks nearly central; anterior series of teeth slightly arched; posterior series nearly straight; margin entire; cavity rather deep.” Rogers, 1837. Length, 5 mm.; height, 5:mm. Occurrence—NANJEMOY ForMATION. Popes Creek, Woodstock, 24 miles above Popes Creek. Collections.—Philadelphia Academy of Natural Sciences, Johns Hop- kins University, Maryland Geological Survey. LEDA CULTELLIFORMIS (Rogers). Plate LVI, Figs. 8, 8a. Nucula cultelliformis Rogers, 183%, Trans. Amer. Philos. Soc., new series, vol. v, p. 339. Nucula cultelliformis H. C. Lea, 1848, Proc. Acad. Nat. Sci. Phila., vol. iv, p. 102. Leda cultelliformis Conrad, 1854, Proc. Acad. Nat. Sci. Phila., vol. vii, p. 29. Nuculana cultelliformis Conrad, 1865, Amer. Jour. Conch., vol. i, p. 13. Nuculana cultelliformis Conrad, 1866, Smith. Misc. Coll. (200), p. 3. Nucula cultelliformis Rogers, 1884, Geology of the Virginias, p. 667. Yoldia cultelliformis Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 5. Leda (Adrana) cultelliformis Clark, 1896, Bull. 141, U. 8S. Geol. Survey, p. 838, pl. XXvViil, figs. 3a, 3d. : Description —*“ Shell ovate, ensiform, somewhat inflated, rounded be- fore, much elongated and tapering behind, the posterior length more than twice the anterior, furnished with very fine, hardly distinct concen- tric striae, and one distinct and one very obscure rib behind; anterior part with an indistinct fold; shell thin; lunule long and lanceolate; beak small; anterior series of the teeth gently arched; posterior series straight; teeth in both acutely bent, the angles directed toward the beak; margin entire; cavity of shell shallow, with a ridge passing from the beak to the posterior margin.” Rogers, 1837. Length, 10 mm.; height, 4 mm. Occurrence—AQuiaA FormMAtTION. Clifton Beach. Nansemoy For- MARYLAND GEOLOGICAL SURVEY 199 MATION. Popes Creek, 24 miles above Popes Creek, Woodstock, Upper Marlboro (deep cut near Chesapeake Beach R. R. station). Collections.—Johns Hopkins University, Maryland Geological Survey. Family LEDIDAE. Genus LEDA Schumacher. LEDA IMPROCERA (Conrad). Plate LVI, Figs. 1, 2, 3, 4. Nucula improcera Conrad, 1848, Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. i, p. 151, pl. xiv, fig. 23. Nuculana improcera Conrad, 1865, Amer. Jour. Conch., vol. i, p. 13. Nuculana improcera Conrad, 1866, Smith. Mise. Coll. (209), p. 3. Leda improcera Clark, 1895, Johns Hopkins Uniy. Circe., vol. xy, p. 5. Leda improcera Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 85, pl. xxviii, figs. la—-1d (not le). Description —* Elongate, very inequilateral, convex, polished, and having fine indistinct concentric lines; anterior side produced, bicarin- ated; the upper margin incurved toward the apex; extremity angulated.” Conrad, 1848. This species shows considerable variation in outline. Conrad’s types are of the more elongate form. If the more elevated form is a con- stant variation it should be separated as a new variety or species. Length, 8 mm.; height, 4 mm. (typical). Length, 11 mm.; height, 7 mm. (elevated form). Occurrence—NANJEMOY ForMATION. Popes Creek, Woodstock, Head of Nanjemoy Creek, 2} miles above Popes Creek. Collections—Johns Hopkins University, Maryland Geological Survey. LEDA PARILIS (Conrad). Plate LVII, Figs. 1, 2, 2a. Nucula parilis Conrad, 1848, Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. i, p. 182, pl. xiv, fig. 31. Nucula parilis Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 93. Description.—* Ovate, ventricose, with concentric lines; beaks medial; anterior end pointed, angular; posterior end regularly rounded; an- terior submargin carinated, hinge margin very oblique, straight from 200 SYSTEMATIC PALEONTOLOGY the apex, except near the end where it is somewhat angulated.” Con- rad, 1848. This very distinct species has been found only in and immediately above the indurated ledge at Upper Marlboro and South River bridge. It is rare in the indurated ledge but abundant in the shell bed imme- diately above it. The type which came from Upper Marlboro is still in the collection of the Philadelphia Academy of Natural Sciences. Length, 15 mm.; height, 9 mm. Occurrence—AQuiA Formation. Upper Marlboro, Sheckel’s Farm near South River. Collections—Maryland Geological Survey, Philadelphia Academy of Natural Sciences. LEDA PARILIS VAR. Plate LVII, Fig. 3. Leda improcera Clark, Bull. 141, U. 8. Geol. Survey, pl. xxviii, fig. le. This form is a connecting link between JL. cliftonensis and L. parilis and might be the descendant of either. It is less globose and has smaller, more numerous folds than L. parilis; and is somewhat more elevated than Z. cliftonensis with smaller, more closely-set folds. Length, 11 mm.; width, 6.5 mm. Occurrence.—NANJEMOY Formation. Hills Bridge, Woodstock. Collections.—Maryland Geological Survey, Johns Hopkins University. LEDA POTOMACENSIS Nn. sp. Plate LVI, Figs. 9, 10. (7) Nuculana protecta Conrad, 1865, Amer. Jour. Conch., vol. i, p. 147, pl. xi, fig. 6. (In part.) Leda protexta Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 5. Leda protecta Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 82. Description —* Shell large, transverse, elongate, anterior side round- ed, posterior somewhat longer, attenuated, terminating in an obtuse beak; surface with numerous concentric striations somewhat interfered with on the rostrated portion of the posterior side, where the riblets become more lamellated and wavy and at times even disappear.” Clark, 1896. MARYLAND GEOLOGICAL SURVEY 201 Nuculana proterta Conrad (1865), which is Leda proterta Harris (1897), includes two forms. The first has been described by Dr. Dall as Leda pharcida and occurs at Wood’s Bluff, Choctaw Corner, and Cave Branch, Ala. The second, which is Leda protexta Clark (1896), is described here, and occurs outside of Maryland at Bell’s Landing, Gregg’s Landing, and Yellow Bluff, Ala. The above localities are all given from material in the collection of the Philadelphia Academy of Natural Sciences. Length, 37 mm.; width, 17 mm. Occurrence—NANJEMOY Formation. Woodstock, West of Port To- bacco, 1 mile southeast of Piscataway, $ mile below Chapel Point, Charles Branch between Rosaryville and Upper Marlboro, Popes Creek. Collections —Johns Hopkins University, Maryland Geological Survey. LEDA CLIFTONENSIS N. sp. Plate LVI, Fig. 11. Description—Shell short, ventricose, posteriorly acute, anterior regu- larly rounded. Surface marked with very regular, concentric folds, with narrow, sharply incised interspaces. Length, 11 mm.; height, 5 mm. Occurrence—AQuiIa FoRMATION. 2 miles below Potomac Creek, Po- tomae Creek, Aquia Creek, Liverpool Point, Clifton Beach. Collection—Maryland Geological Survey. LEDA TYSONI 0. sp. Plate LVII, Figs. 4, 4a, 5. Description.—Shell of moderate size, thin, not extremely inequilateral; beaks large, proximate; anterior end produced, uniformly rounded; pos- terior end broad, uniformly rounded; surface marked by fine, regular closely-set rounded lamellae with narrow interspaces; hinge-line nearly straight with from twelve to fifteen teeth on either side of a subum- bonal chondrophore. This species has some resemblance to the figures of Nucula capsiopsis de Gregorio.’ 1 Ann. Géol. et Pal., vol. ii, p. 187, pl. xxii, figs. 23, 24. 202 SYSTEMATIC PALEONTOLOGY Length, 12 mm.; height, 6.5 mm. Occurrence—NANJEMOY FoRMATION. Popes Creek, Woodstock, 1 mile southeast of Piscataway, 24 to 3 miles above Popes Creek. Collections.—Maryland Geological Survey, Philadelphia Academy of Natural Sciences. Family NUCULIDAE. Genus NUCULA Lamarck. NvucuLa OVULA Lea. Plate LVII, Fig. 6. Nucula ovula Lea, 1833, Contrib. to Geol., p. 80, pl. iii, fig. 59. Description—* Shell ovate, oblique, inflated, very inequilateral, trans- versely striate, longitudinally and very minutely ribbed; substance of the shell thin; lunule large, not deeply impressed; beaks pointed, re- curved; anterior series of teeth short, posterior series long; fosset nearly direct; cavity of the shell deep; margin very minutely crenulate; nacre pearly.” Lea, 1833. Length, 11 mm.; height, 7.5 mm. Occurrence—AQuia Formation. Upper Marlboro, Sheckel’s Farm near South River. Collection.—Maryland Geological Survey. NUCULA POTOMACENSIS N. sp. Plate LVII, Figs. 7, 7a, 8, 8a. Nucula magnifica Clark, 1895, Johns Hopkins Univ. Cire., vol. xv, p. 5. Nucula magnifica Clark, 1896, Bull. 141, U. 8. Geol. Survey, p. 82. Not Nucula magnifica Conrad. Descrvption.—Shell small, thin, fragile; valves shallow; surface mark- ed by strong radial striae which are stronger toward the periphery, and along which the shell tends to fracture; margin strongly crenulated; lines of growth faint and irregular, other concentric sculpture lacking; interior with a silvery luster: beaks anteriorly situated; lunule indis- tinct; chondrophore narrow, oblique; anterior teeth about fifteen, pos- terior teeth about six. aa MARYLAND GEOLOGICAL SURVEY 203 Length, 11 mm.; height, 8 mim. Oceurrence.—N ANJEMOY Formation. Woodstock, Head of Nanjemoy Creek, Charles Branch between Rosaryville and Upper Marlboro, Popes Creek, East and west of Port Tobacco, Upper Marlboro (deep cut near Chesapeake Beach R. R. station), 24 miles above Popes Creek. Collections —Maryland Geological Survey, Johns Hopkins University. MOLLUSCOIDEA. cuss BRACHIOPODA. Order TFELEOTREMATA. Family TEREBRATELLIDAE. Genus PLATIDIA Costa. PLATIDIA MARYLANDICA N. sp. Plate LiVITIS Pics. 15 Vas Ib; ile: Description.—Shell small, subcireular, somewhat depressed, with well- marked lines of growth; ventral valve with hinge-area prominent, high, bisected by a large open foramen and with a well-defined, linear septum in the interior; dorsal valve with large pedicle incision, and with a short, high, slightly bifurcated medium septum in the interior; teeth and sockets prominent; shell structure minutely punctate. This beautiful ttle brachiopod is not uncommon at Upper Marlboro where it is found associated with bryozoans and foraminifera. There is no other American fossil species of this genus. Length, 4 mm.; width. 4 mm. Occurrence—AQquia Formation. Upper Marlboro. Collection.— Maryland Geological Survey. 204. SYSTEMATIC PALEONTOLOGY Family TEREBRATULIDAE. Genus TEREBRATULA Llhwyd. TEREBRATULA HARLANI Morton. Plate LVIII, Figs. 2, 3, 3a. Terebratula harlani Morton, 1829, Jour. Acad. Nat. Sci. Phila., vol. vi, p. 73, pl. iii, figs. 1-4, 7, 8; Amer. Jour. Sci., vol. xvii, p. 283,; vol. xviii, pl. ili, fig. 16. Terebratula harlani Bagg, 1898, Amer. Geol., vol. xxii, p. 570. Description —* Shell large, about twice as long as broad, sides straight and imperfectly parallel; upper valve plano-convex, obscurely bipli- cated except near the margin, which has three inconsiderable sinuses; lower valve very convex, with a longitudinal ridge and slight lateral depressions; beak incurved; umbo prominent.” Morton, 1829. Mr. Schuchert states in a private communication that “The Tere- bratula harlani from the Eocene show a tendency to variation which if constant I would use as-a distinguishing character for the establishing of a variety. This tendency is for the shell to become a little wider with the loss of lobation. Similar shells also occur among the Cretaceous specimens but the form seems to be rare. If in the Eocene this form is the prevailing one then it shows the line of variation in evolution. However, if you give these Eocene specimens a varietal name, call atten- tion to the fact that the identification cannot be made from single specimens. “ Another slight difference is the wide area on each side of the crural processes. This also has no particular value. I should never have be- heved the finding of Terebratula harlani in Eocene strata had I not seen these specimens with your remarks as to occurrence and associated Eocene fossils.” Whether the specimens of Terebratula harlani found associated with typical Eocene fossils are to be regarded as mechanically derived from Cretaceous deposits or are really Eocene representatives of this import- ant species the authors have not been able to determine. A careful study of the many shells found does not afford any evidence that they were transported to any distance although in some instances occurring well above the base of the Eocene. Furthermore, it cannot be definitely MARYLAND GEOLOGICAL SURVEY 205 shown, so far as these occurrences are concerned, that the Rancocas for- mation, to which Terebratula harlani is limited farther north, really ex- ists or ever did exist in the area below the Eocene strata. The specimens obtained, however, are not unlike the Cretaceous forms. It is important in this connection that they have never been observed in the intervening Manasquan and Shark River formations, both of which have furnished a considerable number of other species. The specimens vary considerably in size, although the larger forms predominate. The largest specimens are from 70 to 80 mm. in height and 40 to 50 mm. in width. Oceurrence—AQuta ForMATION. 3 miles west of Leeland, Severn River opposite Annapolis. Collections—Maryland Geological Survey, Maryland Academy of Sciences. CLAss Ba GVAOVE Order CYCLOSTOMATA. Family TUBULIPORIDAE. Genus DISCOSPARSA d’Orbigny. DISCOSPARSA VARIANS 0. sp. Plate LIX, Fig. 3. Description —Zoarium forming subcircular (young) or irregular, un- dulating expansions, 2 to 10 mm. wide, parasitically attached, or more or less free and epithecated beneath. In young colonies which are often spread over the original layer, the zooecial apertures, which are enclosed by moderately elevated, ring-like peristomes, are, sometimes uniserially, but never very regularly, arranged in a radiate manner about the small, depressed and smooth central space. In older examples, there are sey- eral of these maculae, but the radial arrangement of the zooecia about them, is generally obscure. The ooecia immediately surrounding the maculae are often of larger size and more oblique than those covering the intermediate spaces where they are quite direct, but in worn ex- amples very little difference in size is noticeable. The interzooecial 206 SYSTEMATIC PALEONTOLOGY spaces, which are solid and concave normally, are pitted in worn speci- mens as though they contained covered mesopores or vesicles. The un- worn covering is minutely punctate, as are also the covers closing some of the zooecial apertures. The zooecia form mere inflations of the sur- face, usually (perhaps always) over one of the maculae, which in that case is slightly raised instead of depressed and pierced by somewhat scattered apertures. An average of nine zooecia occur in 2mm. Tube walls as seen in fractured specimens, thin beneath the outer crust, min- utely perforated, the pores arranged in transverse series with nearly three of the rows in the space equalling the width of a tube. No diaphragms were observed. Length of tubes, 1 mm. or less. The Lower Eocene specimens have been identified with a common form in the washings of the Upper Cretaceous at Vincentown, N. J. In the latter the arrangement of the zooecia is usually more regular and the maculae scarcely so noticeable as they are in the Upper Marlboro specimens, but other Vincentown specimens agree very closely with the one illustrated on Plate LIX, Fig. 3. The generic position of the species may be considered a trifle doubtful. The wholly parasitic specimens would probably be placed by most authors under Berenicea, but it does not seem that the species in any of its forms is ever truly a Berenicea. Besides, these parasitic specimens cannot possibly be distinguished in other respects from the free laminar and even discoid specimens here united with them. Duscosparsa as established by dOrbigny and ac- cepted by Pergens, includes discoid or cupuliform zoaria, attached by the central portion of the base only. The zooecial apertures are dis- posed irregularly or in intersecting curved lines about the center of the upper surface. As these conditions are fully complied with by at least some of the Vincentown specimens of D. varians, it appears reasonable to place the species under Discosparsa rather than Berenicea. There is no described American species closely resembling D. varians and none of those from European deposits seem near enough to require detailed comparison. The species is common in the Upper Cretaceous at Vincen- town, N. J. Occurrence—AQuia FormMATION. Upper Marlboro. Collection—Maryland Geological Survey. MARYLAND GEOLOGICAL SURVEY 207 Family FASCIPORIDAE. Genus FASCIPORA d’Orbigny. FASCIPORA SUBRAMOSA DN. sp. Plate LIX, Figs. 1, 2. Description.—Zoarium consisting of smal] flattened branches, varying from subcylindrical to flabellate, usually about 1.5 mm. in thickness. Ends of branches convex, occupied by the mouths of numerous sub- equal, thin-walled, angular tubes, usually about 0.12 mm. in diameter. Sides of branches with rather obscure transverse wrinkles and the aper- tures of the true or fully-developed zooecia. The latter are somewhat scattered, though a tendency to arrangement in series—chiefly longitu- dinal—is commonly apparent. The rounded contour of the zooecial tube-wall is but dimly discernible behind the moderately raised aper- tural rims. Zooecial apertures ovate, about 0.14 mm. by 0.18 mm., with about five in 2 mm. Interapertural space as well as apertural covers, minutely punctate. In vertical fractures the tubes are shown to be very long and that they approach the surface very gradually. Ooecium a mere inflation of the surface through which one or more of the zooecial tubes pass. In the general form of its zoarium this species agrees very well with F. pavonina (Michelin) d’Orbigny’s type of the genus, but its zooecia are much smaller and not nearly so prominent. Occurrence—AQui1a Formation. Upper Marlboro. Collection.—Maryland Geological Survey. Family IDMONIIDAE. Genus RETICULIPORA d’Orbigny. RETICULIPORA DICHOTOMA Gabb and Horn. Plate LIX, Figs. 9-12. Reticulipora dichotoma Gabb and Horn, 1862, Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. v, p. 173, pl. xxi, fig. 64. Comp. Bicrisina gandryana Pergens, 1890, Revis. des Bryozoaires du Crétacé, Bull. Soc. Belge de Géol., t. ili, pl. xiii, fig. 2. Description—Fragments only of this species havé been seen. So far as these admit of judging, the zoarium is not reticulated but consists of 208 SYSTEMATIC PALEONTOLOGY laterally compressed curved branches, 2 to 3 mm. wide or high and 1 mm. or less thick, throwing off similar branches from their sides. Oc- casionally they appear to divide dichotomously, but this probably is not really the case. The zooecial apertures are subcircular or oval, 0.08 to 0.10 mm. in diameter, arranged in more or less irregular transverse series, five or six in 1 mm., oblique, with the peristome higher behind than in front. Except for an occasional large cell (? zooecium) the lower third or half of the branches is without zooecial apertures and in the worn condition may appear quite solid. When in a good state of preservation, however, this part of the surface is covered by angular depressions, of varying sizes, the centers of the depressions usually show- ing the mouth of a small pore. Similar pores extend upward and oc- cupy the depressed spaces between the rows of zooecial apertures. Gon- ocysts of the same type as in Berenicea, Discosparsa and Fascipora. The zooecial tubes pass through them without interruption, but the mesopores do not. Closures of zooecial tubes, some distance below the external orifice, appear to have a central perforation. A species recently described by Pergens (loc. cit) from the Cretaceous (Senonien) of France, under the name of Bicrisina gaudryana, is either the same as Ff. dichotoma or extremely like it. The species occurs in the Upper Cretaceous at Timber Creek and Vincentown, N. J. Occurrence. Aqguta Formation. Upper Marlboro. Collection. Maryland Geological Survey. Family CERIOPORIDAE. Genus CAVARIA Hagenow. CAVARIA DUMOSA N. sp. Plate LIX, Figs. 4-8. Description.—Zoarium forming small, bushy masses, consisting of fre- quently and irregularly dividing and coalescing branches, varying in thickness generally from 1.5 to 2.0 mm., but occasionally reaching 3.0 mm. Surface of the most nearly perfect specimens exhibiting at irreg- ular intervals; small, slightly depressed maculae, smooth or occupied solely by mesopores. In these specimens the zooecia are readily dis- tinguished from the mesopores by their prominent peristomes and 7! MARYLAND GEOLOGICAL SURVEY 209 rounded as well as larger apertures. The mesopores occur in the maculae and in the depressed spaces between the zooecia, are something like twice as numerous as the latter, and have small though variable apertures set in the bottoms of rounded or angular depressions. Inner diameter of zooecial apertures about 0.8 mm., with four in the space of 1.0 mm. In young or slightly worn examples the maculae are not readily distinguished, the mesopores relatively larger and the two sets of mouths more nearly alike than in the condition described above. Gonocysts large, appearing as rounded or irregular inflations of the surface perforated by the mouths of zooecial tubes which pass through them without interruption. Beside each zooecium is the orifice of a smaller tube, the nature of which is not understood. When the outer wall of the gonocyst is broken away, the zooecial tubes, together with the small tubes accompanying them, are turned in every direction away from the center. Between them the mouths of the mesopores are covered by a perforated pellicle. The axial hollow or tube varies between 0.2 and 0.4 mm. in diameter, is wrinkled transversely and further constricted at irregular intervals. At the constrictions a thin curved plate is often observable, but that it extends completely across the cavity has not been observed and from the evidence at hand it is at least doubtful that it ever does. The tubes, as seen in fractures, present no evidence of diaphragms, but the con- necting perforations in the walls are quite distinct. They occur mostly in transverse rows, two or three of the rows in a space equalling the width of a tube. Superficially there is considerable resemblance between this species and Heteropora (Multicrescis) parvicella Gabb and Horn, a common fossil of the Upper Cretaceous deposits at Vincentown, N. J. The ramulets of that species, however, are more slender and divide less frequently while its zooecia and mesopores appear more scattered. But the prin- cipal difference hes in the central hollow which is wanting in Gabb and Horn’s species and distinguishes Cavaria from Heteropora. Of the three species of Cavaria described by Hagenow, only C. ramosa, the type of the genus, is at all similar. In this the axial hollow is rela- tively larger and is crossed by strong transverse partitions. The branches 14 210 SYSTEMATIC PALEONTOLOGY also appear to be smaller and the apertures of both zooecia and meso- pores smaller, more angular and less regularly disposed than in C. ra- mMOsa. Occurrence—AQquia Formation. Upper Marlboro (in fragments). Collection—Maryland Geological Survey. Genus CERIOPORA Goldfuss. CERIOPORA MICROPORA Goldfuss. Plate LIX, Figs. 13, 14. Ceriopora micropora Goldfuss, 1822, Petr. i, p. 33, pl. x, fig. 4d (not 4a-c). -Ceriopora micropora Hagenow, 1851, Die Bryozoen der Maastrichter Kreide bildung, p. 52, pl. v, fig. 4. Description Among the Survey material received for description is a single zoarium agreeing too closely with C. micropora, as redefined by Hagenow and represented by several examples in the author’s private collection received from Dr. Ed. Pergens, to admit of distinguishing it at present. ‘The specimen is depressed globular in shape, nearly 5 mm. in diameter, hollow beneath, and composed of at least three layers of zooecia. The zooecial apertures are not very clearly shown by the speci- men but appear to be a trifle smaller, more unequal and thinner walled than in the Maastricht colonies. Occurrence. NANJEMOY ForMATION. 24 miles above Popes Creek. Collection.—Maryland Geological Survey. Genus HETEROPORA Blainville. HETEROPORA (?) TECTA 0. sp. Plate LIX, Figs. 15, 16. Description.—Zoarium consisting of small, subramose masses or stems, 2 or 3 mm. in thickness, the upper ends of which are rounded and coy- ered uniformly with angular thin-walled tube mouths, about seven in 1mm. A large proportion of the sides of the specimen figured is cov- ered with a thin and minutely punctate pellicle, the tube apertures covered thereby being quite obscured. Most of the apertures showing through or piercing the pellicle, are of rounded form, with an inside diameter of about 0.13 mm., and enclosed by a ring-like peristome. MARYLAND GEOLOGICAL SURVEY 211 These are regarded as the true zooecia, the other tubes being probably all of the nature of mesopores. In longitudinal sections the tubes have thin walls, perforated as usual, are developed in any part of the axial region and approach the surface in a very gradual curve. No dia- phragms were observed. No /Teteropora has been seen by the author that resembles this spe- cies very closely. Indeed, there is a doubt regarding its belonging to this genus, but, after comparing it with all the described genera of this section of the Cyclostomata, it appears to agree better with Heleropora than with any of the other genera. Occurrence—AQuia Formation. Upper Marlboro. Collection.—Maryland Geological Survey. Order CHILOSTOMATA. Family MEMBRANIPORIDAE. Genus MEMBRANIPORA Blainville. MEMBRANTIPORA RIMULATA N. sp. Plate LX, Figs. 1, 2. Description—Zoarium adnate, forming a thin, single sheet of indefi- nite extent. Zooecia hexagonal in form, arranged quincuncially with the longitudinal rows generally very regular. Apertures occupying the whole of the large opesium, quite regularly ovate in shape. Rim or interapertural space narrower than the opesia, rounded, sometimes an- gular in the middle but oftener with a depressed interzooecial suture line, marked with close transverse lines or wrinkles. Taking the place of an ordinary zooecium isolated cells or, more commonly, two or three in longitudinal sequence, occur which differ from the rest in having a convex cover with a narrow median slit and above the slit a linear cres- centic impression. These cells may represent an unusual type of ocecia but more probably are to be considered as a form of vicarious avicularia or vibracula. The specimens upon which the species is founded are divisible into two varieties, one with smaller zooecia and opesia and thicker walls Al SYSTEMATIC PALEONTOLOGY than the other. Measuring longitudinally the former has four and one- half zooecia in 2 mm., the other only three and a half. Diagonally one - has six, the other five in the same space. Thickness of zooarial sheet not exceeding 0.2 mm. Membranipora perampla Gabb and Horn, which occurs rather fre- quently in the Upper Cretaceous at Vincentown and other points in New Jersey, sometimes resembles this species, but its zooecia are larger, less regular, with irregular spaces often between the rims and one side of the latter generally higher than the other, while none of the covered cells described above have so far been observed in it. The zooecia are more regularly arranged in M/. rimulata than in any of the simple spe- cies of the genus known to the writer, and this fact, together with the presence of the peculiar covered cells, is principally relied upon in dis- tinguishing the species. Two fragments in my collection of Cretaceous bryozoa found at Vincentown, N. J., and regarded as Biflustra disjuncta Gabb and Horn, have very similar covered cells, and, considering the variations shown in my specimens of this species, seem to show a closer relation to M. rimulata than to any other form. Occurrence—AQuia Formation. Upper Marlboro. Collection.—Maryland Geological Survey. MEMBRANIPORA SPICULOSA 0. sp. Plate LX, Figs. 3, 4. Description.—Zoarium adnate. Zooecia arranged in quincunx or ir- regularly, oblong, rounded and widest above, more or less produced be- low. Opesia large, normally ovate, the upper edge nicely rounded, the lower variable, taking up about half of the length of the zooecium. Rim thin, highest above, usually dying out before reaching lower ex- tremity of zooecium. Front wall over lower half of zooecium, slightly depressed, covered with small granules or spines, those bordering the edge projecting sharply into the opesial opening. Ooecia numerous, cucullate, strongly elevated, often with a tubercle or point forming the summit. When a zooecium is without an ooecium its place is often oc- cupied by an elevated avicularium of moderate size. The avicularia are yery few in number but when present similar to those found in Repto- MARYLAND GEOLOGICAL SURVEY 213 flustrella heleropora Gabb and Horn. mim.; width 0.25 to 0.30 mim. Length of zooecium 0.5 or 0.6 The specimen described shows a single cell differing from the rest in being closed, a convex cover, at the upper extremity of which a semi-circular impression is distinguishable, extend- ing over the whole. Occurrence.—AQUIA FORMATION. Upper Marlboro. Collection.—Maryland Geological Survey. MEMBRANIPORA ANGUSTA N. sp. Plate LX, Figs. 5, 6. Description—Among the material from Upper Marlboro, there are several specimens of a delicate Membranipora that, on account of their imperfection and fragile nature, it may be risky to distinguish as a new species. However, as it is easily recognized and may prove useful in stratigraphic studies the writer has ventured to name it as above. The zooecia are shallow, elongate, elliptical, hexagonal or rhomboidal and separated except in young stages by a thin tuberculated wall common to adjoining cells (1. e. there is usually no depressed dividing line between the zooecia). The inner portion of the wall is much thicker than the outer, so that the mouths of the connecting pores, of which there are at least six on each side and one or two at each end, are clearly shown in a view of the front. Two specimens have cucullate ooecia as shown in Figure 5, and on all an occasional small oval or rounded and slightly raised avicularium may be noticed. The zooecia are about 0.4 mm. long and 0.2 mm. wide. MM. angusta apparently belongs to the M. lineata group of Waters. Occurrence—AQuvuia Formation. Upper Marlboro. Collection.—Maryland Geological Survey. Genus REPTOFLUSTRELLA d’Orbigny. REPTOFLUSTRELLA HETEROPORA Gabb and Horn. Plate LX, Figs. 8, 9. Reptoflustrella heteropora Gabb and Horn, 1862, Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. v, p. 162, pl. xx, fig. 50. Description.—*< Colony encrusting in irregular patches. Cellules in a single layer, placed with but little regularity, but with a tendency to 214 SYSTEMATIC PALEONTOLOGY radiating lines; elongate, acuminate anteriorly, broadly truncate behind. Opening subtriangular, with the sides convex, often approaching an oval in very long cellules. Surface regularly convex, bordered anteriorly and laterally by a slightly elevated, rounded edge, usually becoming obsolete as it approaches the proximal end of the cellule. Special pore placed in advance of the opening, small and round. No ovarian vesicles were observed. Old cellules are closed over by a continuation of the surface wall totally obliterating the aperture. In this case the ‘special pore’ is also generally obliterated, merely showing a shght depression.” Gabb and Horn, 1862. The Eocene specimens are coarser in appearance than the Cretaceous form of the species, of which the writer has a number of excellent examples. ‘They differ further in the more pronounced character of the granulation of the front wall and opesial margin, the Cretaceous form being almost smooth; in more frequently assuming a rhomboidal form of zooecium; and in the relatively smaller size of the opesium and larger avicularia. Cucullate ooecia, less prominent but otherwise similar to those of Membranipora spiculosa, occur not infrequently upon the Cre- taceous specimens but are wanting on the Hocene material in hand. When these occur they take the place of the avicularium which other- wise occurs invariably on, or, just above, the upper rim of the zooecium. The species oceurs in the Cretaceous at Mullica Hill, Timber Creek, and Vincentown, N. J. Membranipora spiculosa is a closely related species, but has a more ovate and larger opesium and differently shaped zooecia. Occurrence—AQqutia Formation. Upper Marlboro. Collection.—Maryland Geological Survey. Genus BIFLUSTRA d’Orbigny. BIFLUSTRA TORTA Gabb and Horn. Plate LX, Fig. 7. Biflustra torta Gabb and Horn, 1862, Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. v, p. 152, pl. xx, tig. 36. Description Colony composed of very compressed branches, usu- ally twisted, rarely in the same plane for more than a quarter of an d a MARYLAND GEOLOGICAL SURVEY 215 inch. Cellules arranged in longitudinal lines and usually in quincunx. About six to ten rows on each side of the branches, although we have in one case counted twenty just below a bifureation. Cellules closely jux- taposed; elongated oval anteriorly, contracted and afterwards dilated posteriorly, and straight or slightly emarginate at the proximal edge. Opening elongated oval, variable in form and size, occasionally sub- quadrate, sometimes slightly narrowed posteriorly, either more or less than half the surface of the cellule, no lip or margin, simply pierced in the substance of the cellular wall and placed at the lowest part of the surface. Surface smooth, concave, elevated at the anterior and antero- lateral margins into a rounded or acute edge, a little higher than the posterior of the surface of the adjoining cellules. From this edge the surface slopes inwards toward the mouth. Behind the mouth the sur- face is generally marked by two radiating depressed lines, running from the proximal corners of the mouth to the corresponding corners of the cellule, between which is a rounded elevation, not as high, however, as the anterior end of the preceding cellule. The accessory cells [ vicarious avicularia] appear to be ordinary cellules undeveloped, and are not always placed immediately in advance of an ordinary cellule. They are about two-thirds of the ordinary size, not closed above, by a testaceous covering, but have the anterior edge very much produced, thin and overhanging, and about as high as the length of the aperture. We have noticed but one broken ovarian vesicle, which is placed in advance of the cellule to which it belongs, appears to have been semiglobular and overlaps the proximal surface of the succeeding cellule, reaching to the edge of the aperture.” Gabb and Horn, 1862. Although rather variable this is still to be counted as an easily recog- nized species. Ooecia occur but rarely, only four or five specimens out of fifty or more in my collection having any at all. They are cucullate, often with a delicate longitudinal ridge across them and about as large as in Membranipora spiculosa, but more uniformly convex. The species occurs in the Upper Cretaceous at Mullica Hill, Timber Creek, and Vincentown, N. J. Occurrence.—AQuia ForMATION. Upper Marlboro. Collection.—Maryland Geological Survey. 216 SYSTEMATIC PALEONTOLOGY EscHara (??) pigirata Morton.’ Plate LX, Figs. 10, 11. Eschara digitata Morton, 1834, Syn. Org. Rem. Cretaceous Group, p. 79, pl. xili, fig. 8. Eschara digitata Lonsdale, 1845, Quart. Jour. Geol. Soc. London, vol. i, p. 73, figs. c, d, g, (a4 and 6?) exclus. e and f. me Eschara digitata ad’ Orbigny, 1850, Prod. Pal. Strat., vol. ii, p. 264. Eschara digitata Gabb and Horn, 1862, Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. v, p. 114. i Description.—Zoarium bifoliate, branching dichotomously; branches flattened, acutely elliptical in cross-section, usually 2.5 to 3.0 mm. wide. Zooecia hexagonal, regularly arranged in quincunx, about 0.55 mm. long and 0.38 wide, bounded by a slightly impressed line; surface concave, especially toward the aperture which is situated usually just in front of the center. Aperture semielliptical, rounded in front, straight behind, 0.10 to 0.12 mm. wide. Normally developed and perfect, the posterior border of the aperture is slightly raised and bears a delicate lunarium- like curved plate which extends into the aperture. Abortive cells, pos- sibly of the nature of vicarious avicularia, are frequent but seem to be entirely restricted to the edges of the zoarium and to those portions lying just beneath the axes of bifurcation. They are distinguished from the other cells by their subcircular and usually much smaller apertures. Ooecia unknown. The species occurs abundantly in the Upper Creta- ceous at Mullica Hill, Timber Creek, and Vincentown, N. J. Occurrence—AQuIA ForMATION. Upper Marlboro (rare). Collection.—Maryland Geological Survey. 1Of course this species does not belong to the genus Hschara as now understood. Like Biflustra torta it belongs near or to the genus Onychocella Jullian, which is variously regarded, by some as a mere section of Membranipora, by others as a distinct genus or even as the type of anew family, while Gregory makes it a member of the Microporidae. At present I regard Onychocella, taking such a form as Membranipora angulosa Reuss, as a typical species, as clearly entitled to generic rank and as probably representing a distinct family. It would, however, to say the least, be premature to place either Biflustra torta or Hschara digitata under Onychocella, since neither accords strictly with the more typical species of the proposed genus. When raised to the rank of a family it is highly probable that other generic groups will be established into which these species would fall more naturally than into Onychocella proper. Careful Mr. Waters has already instituted a second genus of the Onychocella type— Vibracella—tfor Flustrellaria trapezoidea Reuss, while it may yet become desirable to employ some of the names proposed by d@’Orbigny for related types. Under these circumstances I prefer leaying the species where Gabb and Horn placed them. MARYLAND GEOLOGICAL SURVEY PAW ¢ Genus LUNULITES Lamarck. LUNULITES REVERSA 0. sp. Plate LX, Figs. 19, 20. Description—Zoarium flabellate (perhaps originally discoid or de- pressed conical), zooecia subquadrate or pentagonal, usually widest in the anterior half, arranged in rather irregular radiating lines, about six in 2 mm., with an impressed line separating the rows; area depressed, its sur- face grano-lineate. Margin strongly raised, thick, and straight or slightly concave across the posterior end and much thinner along the sides, the anterior end appearing to be overlapped by the posterior ridge of the next succeeding zooecium. Aperture surrounded by a thickened rim, generally rounded in front and straighter behind, sometimes sub- quadrate, its anterior border close to the prominent end of the next cell, and the length and width averaging about half the corresponding dimen- sions of the entire zooecium. Vibracular cells fusiform or elongate oval, rather large, one, usually at each angle of junction between four zooecia. A constriction occurs near the center of each, sometimes on one side only, at other times on both. A narrow area may surround the opening. Under surface marked by irregular depressed lines radiating from the narrow lower extremity of the zoarium. Between these lines the surface is convex and rather coarsely pitted and granulate. The only specimen seen is too imperfect to permit a positive declara- tion that it is not a mere fragment of a discoid zoarium. Still, the arrangement of the depressed lines on the lower surface does not look right for a species in which the zooecia radiate from a center as in the ordinary forms of Lunulites. On the other hand this side looks de- cidedly like d’Orbigny’s figure of his Pavolunulites elegans (Pal. France., vol. v, pl. deevi, fig. 7), hence I expect to find that perfect specimens of L. reversa have a flabellate and not a discoid or conical form. Specifically, Z. reversa is distinguished from all species of Lunulites known to the writer, except L. regularis dOrbigny, L. semilunaris Marsson and ZL. patelliformis Marsson, in haying the posterior margin of the zooecium thicker and more premoinent than the anterior. From the species mentioned it differs in the greater elevation and square out- 218 SYSTEMATIC PALEONTOLOGY line of the raised margin, in the larger size and different form of the aperture, and the grano-lineate marking of the whole surface. Occurrence.—AQUIA FoRMATION. 2 miles below Potomac Creek. Collection. Maryland Geological Survey. Family CRIBRILINIDAE. Genus CRIBRILINA Hincks. CRIBRILINA MODESTA 0. sp. Plate LX, Figs. 12, 13. Description.—Zoarium forming a delicate parasitic patch upon foreign bodies. Zooecia ovate, not very regularly arranged, about 0.4 mm. in length and 0.28 mm. wide, bordered by a thin rim. Front wall gently convex, usually with six (five to seven) radiating and transverse furrows, each with two or three pores, on each side, and a central, flattened, ovate or triangular space, including five or six similar pores placed in obscure transverse furrows. Apertures rounded, prominent, oblique, the pos- terior edge highest and often thickened in its central portion. Small avicularian cells occur near or attached to one part or another of the apertural rim of most zooecia, generally one to each, rarely two. Where three zooecia join there is usually a small open space (? vibracular cell). Ooecia cucullate, moderately arched. I could find none among the numerous species of Oribrilina and the related, if not congeneric, forms referred to Hscharipora, Semieschari- pora and Reptescharipora by VOrbigny that exactly matches the fossil above described. It is distinguished from nearly all of them by the eribrose, central space on the front wall, and the prominent rounded aperture. Occurrence—AQuia Formation. Upper Marlboro. Collection.—Maryland Geological Survey. CRIBRILINA CRASSULA N. sp. Plate UX, Fig. 14. Description.—Zoarium encrusting. Zooecia oblong quadrate or hexa- gonal, irregularly arranged, with a heavy, strongly elevated margin, SS a ee ee ee MARYLAND GEOLOGICAL SURVEY 219 clithridate in outline. Front wall with a narrow raised ridge running down its center, and five or six transverse and radiating rows of minute punctures lying in furrows. Apertures rounded or suboyate, the outline often less curved on the posterior side than elsewhere. Avicularian cells small, raised, variously distributed, sometimes one or two and even three to a zooecium; or a cell may have none at all. Ooecia unknown. Zooecia 0.5 to 0.6 mm. in length, 0.25 to 0.30 mm. wide; about seven in 4 mm. measuring lengthwise. The thick marginal rim of the zooecia and the unusual depression of the front wall are regarded as the distinctive characters. The latter feature seems to occur also in Hscharipora immersa Gabb and Horn, a species described but unfortunately not figured in their monograph, and founded on a specimen from the Cretaceous at Timber Creek, N. J. Their description leaves much in doubt, but as it is stated that the zoarium forms broad, tortuous and anastomosing plates, celluliferous on both faces, and that the zooecia are arranged in regular quincunx, it seems highly improbable that C. crassula can be the same species. Of other Cribrilinidae known to the writer only Escharipora incrassata dOrbigny, from the Cretaceous of France, presents considerable resem- blance. That species, however, grows into bifoliate expansions, has larger and relatively longer zooecia and large accessory cells (? vicarious avicularia) not observed in C. crassula. Occurrence—AQuia Formation. Upper Marlboro. Collection Maryland Geological Survey. Family ESCHARIDAE. Genus LEPRALIA Johnston. LEPRALIA SUBPLANA D. sp. Plate LIX, Figs. 17, 18. Description.—Zoarium, as seen in three specimens, forming a hollow cylinder, composed of numerous layers, each 0.3 to 0.35 mm. in thick- ness, and varying in diameter according to the number of layers from ”.0 to 13.0 mm. Zooecia not very regularly arranged, sometimes subo- vate, at other times hexagonal or subquadrate, longer than wide, the length averaging about 0.45 mm. Upper surface nearly flat, the outline 220 SYSTEMATIC PALEONTOLOGY of the zooecia, in aged conditions especially, scarcely distinguishable and mainly by a double row of pores which, as shown by fractures, are the mouths of small tubes traversing the walls in a vertical direction. Front wall slightly convex, perforated, the pores usually smaller than those outlining the zooecia, distinctly visible on the inner surface, sometimes wanting over a varying space just behind the aperture. ‘The latter is rounded in front, nearly straight behind, with the angles rounded, gen- erally semielliptical, the width and length averaging, respectively, 0.15 and 0.13 mm. Small, round or oval avicularia generally present. Their position is variable though usually close to the rim of the aperture. While an occasional zooecium may occur, having no avicularia, as many or more will be found having one on each side of the aperture. Ooecia unknown. . Fractures dividing the zooecia vertically (see Fig. 18) show that the walls (side and front) are traversed by minute, wavy, vertical tubul and that the zooecial cavities are connected by two series of pores, the larger set near the bottom and a row of smaller pores above the midhight. The openings of the larger set are often irregularly distributed over the concave floors of the zooecia. A fine specimen from the Cretaceous at Vincentown, N. J., is of a species closely related to L. subplana but distinguished by several readily apparent differences. In it the young zooecia are more convex than in L. subplana, and the convex portion entirely without perforations. With age, however, the surface becomes distinctly pitted. The vibracula also are more regularly and numerously developed, most zooecia haying one on each side of the aperture. The Vincentown specimens may belong to Gabb and Horn’s Reptocelleporaria aspera but certain discrepancies between it and their description and figure render a positive identifi- cation impossible at present. Occurrence—AQuiA Formation. Upper Marlboro. Collection.—Maryland Geological Survey. LEPRALIA LABIOSA N. sp. Plate LX, Figs. 15, 16. Description.—Zoarium forming thin crusts over shells and other for- eign bodies. Zooecia rhomboidal, hexagonal or subovate, arranged more MARYLAND GEOLOGICAL SURVEY Ral or less irregularly in curved series, five or six in 2 mm. often separated by a depressed line. Front wall punctate, slightly convex, flat, or de- pressed, the last when the margin on one or both sides is thickened and elevated. Aperture subquadrate or semielliptical, sometimes contracted near the middle, always enclosed by a more or less strongly thickened rim. LOLODWS (OBLIQUUSPNGASSIZ erasure cele ces tetera leila ieenoricrele 106 Inner face of an anterior tooth belonging to an immature indi- vidual, and corresponding in size to the lateral tooth shown in Fig. 5. Liverpool Point. . Lateral aspect of same specimen. Outer face of same specimen. Inner face of a lateral tooth belonging to an immature individual. Liverpool Point. . Lateral aspect of same specimen. . Outer face of same specimen. Outer face of a lateral tooth, with a well-developed pair of lateral denticles. Aquia Creek. Lateral aspect of same specimen. Inner face of same specimen. . Inner face of an unusually large and massive tooth with erect crown, entire edges and large lateral denticles, showing transi- tional characters between Carcharodon and Lamna. Glymont. . Lateral aspect of same specimen. Outer face of same specimen. EOCENE, PLATE XV. MARYLAND GEOLOGICAL SURVEY. PESCES: PLATE XVI. PAGE Figs. 1-4. BYTHOCYPRIS SUBAEQUATA Nl. SP. ....-.-. 0. ss ce cee s este eeeeees 116 . Right side of an entire carapace. Upper Marlboro. Dorsal view of same. Anterior view of same. . Inner side left valve showing internal marginal plate. ww Hh 1OUGS, G8 IBWWEOCMIPIRUS TANRIOLIS M, S]Os coocacocoococcccoscabencuveccueC 117 5. Right side of entire carapace. Upper Marlboro. 6. Ventral edge of same. 7. Inner side of right valve. 8. Inner side of left valve. Wigs. 9-13. CyTHERELLA MARLBOROENSIS N. SP...... .....2 cece eee eee ee eee 117 9. Left side of a perfect carapace. Upper Marlboro. 10. Right side of another specimen from same locality. 11. Dorsal view in outline of same. 12. Inner side of a right valve. 13. Anterior end view. JTS. U4), (CRUMENT TO IGIoN, SOMME MIEN Me BJs scoacovoc0ess codcconuo0cc 118 14. A left valve showing slight mesial depression and marginal rim. Upper Marlboro. 15. Ventral view of same. Higs. 16-18. COy@HBRE MARYGANDICA mn. Sp. 2..--..-..-0+5. sees sense ree - == 119 16. Posterior end view of an entire carapace. Upper Marlboro. 17. Right side of same. 18. View of ventral edge of same. Migs, 19-215 (CYIAEREIS) BASSEERT M.cSpeeeere man: oct n ace ie eae 120 19. An average left valve of this species. 20. Ventral edge of an entire carapace. 21. Outline view of anterior end of same. IBIS, Bea (CMAN AIO IAN VARC AMON i Ss socacooocenanc esonaouecaauc 121 22. View of a right valve. 23. Ventral edge of same. All the figures are magnified 20 diameters. 268 MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE XVI. 13 14 16 15 a, ary oes ves tt Sy = 21 23 ARTHROPODA—CRUSTACEA. a 7 " =" j » atid S re a - ~ is Sore ; ; ay 2 * : ey ' a = " 5 ‘as ve ‘ : ; Pa rad 4 PLATE XVII. | bes PAGE ISRO OO CONS eM TON SONAL I S]ak “sean eS ow teak se sooeesasaseadnesscse ccc oonccess 122 Lateral view of smaller type. Popes Creek. — =X 2 269 MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE XVII I / utyset ph yadheeeehe i ih | nM MOLLUSCA—CEPHALOPODA. PLATE XVIII. PAGE HERCOGLOSSA TUOMEYI Nn. Sp. ........-..-- : Heese cee Lateral view of larger type, show ing asments af hell ualbetanice with lines of growth. Popes Creek. xX % iw = So MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE XVIII. ; i ah ib i ory MOLLUSCA—CEPHALOPODA. PLATE XIX. PAGE Jeers, TESS TeLOIRXCOCICOSVA, UWOMNONGE Ms SOs oscuodeadcaccoudsegddsanoneueseooos 122 1. Peripheral view of specimen illustrated on Plate XVII. Popes Creek. xX % 2. Specimen showing fragment of shell substance from near periphery. Popes Creek. X Zs 3. Specimen showing a fragment of shell from near the umbilicus. Clifton Beach. ; cos] = MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE XIX PD MOLLUSCA—-CEPHALOPODA. PLATE XX. PAGE Bes. tla, 22 “LORNA TELLARAS BREEAS Conrad «2/2 !¥s242 2 Ses cesar eae 123 1. Aquia Creek. U. S. National Museum. la. Dorsal view of same specimen. 2. Aquia Creek. Acad. Nat. Sci. Phila. Lea Memorial Coll. Riswoy cas, RINGIGHMAL DALE Olanks.3t 0262.0 usp aaa if eu este. 124 3. Dorsal view. (After Clark.) Woodstock. 3a. Ventral view of same specimen. (After Aldrich.) Bessy 4a ot GI CEN Aug WEN SP Aw Oetker 525). servers sie egaleteel ees eters eratete eater ata tore 124 4. Ventral view of type specimen. Woodstock. 4a. Dorsal view of same specimen. Rios) 5,054, 6.) “PL HUROUOANA, HAPRISH Clark 2. seca. so ees see ee eee een eo 5, 5a. Original figures of type specimen. Potomac Creek. 6. Specimen with more distinct sculpture. Same locality. Wigs: - 1, (a. ELEURO TOMAS POTOMACENSIG: Ws SDs co ci-tacieisen racine aerators 126 7. Ventral view of type specimen. 2 miles below Potomac Creek. 7a. Dorsal view of type specimen. Bie. S$: PLEGROTOMAS DUCATELE Th. SPs cccon ccc sec cca eee ae eo eee 126 Dorsal view of type specimen. 1 mile southeast of Mason Springs. Bion Eb O ROMA EY SOND, 155 S[0s. crete na) eo1- felonies saree eres 126 Ventral view of type specimen. 1 mile southeast of Mason Springs. IDS Rae DBaviaaaounon ue Celseaeipiidowae IVGH! Coe see eeereceecuccoceretcr crs 127 10. Ventral view of broken specimen. 1 mile southeast of Mason Springs. : 11. Dorsal view of more nearly perfect individual. Rip d2. PLEGROLOMA PISCATAVENSES N(SP. o-oo sens cee acs era toe ere 127 Dorsal view of type specimen. 1 mile northeast of Piscataway. Figs. 13, 13a. MANGILIA (PLEUROTOMELLA) BELLISTRIATA Clark......... 128 13. Ventral view of type specimen, enlarged as indicated. Popes Creek. 13a. Dorsal view of same specimen, natural size. MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE XX. MOLLUSCA—CEPHALOPODA. PLATE XXI. PAGE Fig. 1. CANCELLARIA GRACILOIDES Aldrich var. ................ Wonsicheioers 128 Ventral view of specimen from 1 mile southeast of Mason Springs. Tisai Paw (CHAIN KCI DN Gu Ey EAC S] OAS Sy gea webs boecon be CedaaD aacbennse od osn6bobo0 Do cone] Lee) Much enlarged view of specimen eon 2 miles below Polen Creek. Figs. 3, 3a. CANCELLARIA (NARONA) POTOMACENSIS n. Sp. ............. > IBD 3. Ventral view of specimen from 1 mile northeast of Piscataway. 3a. Dorsal view of same specimen. Figs. 4, 5, 5a. VOLUTILITHES PETROSUS (Conrad) ..................-.... . 130 4. Pomonkey Neck. U. S. National Museum. 5. Dorsal view. Potomac Creek. 5a. Ventral view of same specimen. BIS S65) Gan MOLUWIWENIEES WGI) is eee orcicisrcie) caseriers siceue llerorer we rere tee ee ere 6. Ventral view of cast. Aquia Creek. 6a. Dorsal view of same specimen. IOUS, Te S (CARICMILIDA Tyagiicormoiss| (2) (Command!) scoccccaccocacucecceoses 131 7. Spire and part of body whorl. Potomac Creek. ° 8. Cast. Aquia Creek. IDS, 8), Bel ING YN GWUAEaWNNGOMCUN Cllewelic sognoseccadodo075 Sea eeareee hn crane 132 9. Dorsal view. Pomonkey Neck. U. 8S. National Museum. 9a. Ventral view of same specimen. Tess WO, Oz, MGR IROMMONKGONISIIS IM, SB] cocaccsccscgdcodounbsoccoucues . 132 10. Ventral view. Pomonkey Neck. U. S. National Museum. 10a. Dorsal view of same specimen. Fig. 11. Mirra POTOMACENSIS n. sp. ..... wishia rate Wcnee eteirekenenn eis coualatene eee renner 133 Enlarged view. 1 mile northeast of Piscataway. Figs. 12, 12a. LATIRUS MARYLANDICUS n. Sp. ..........-. i europea eker Sccgayreheuens 133 12. Ventral view. 2 miles below Potomae Creek. 12a. Dorsal view of same specimen. ore fo EOCENE, PLATE XxX\I. MARYLAND GEOLOGICAL SURVEY. GASTROPODA. A LOLLUSE N PLATE XXII. PAGE Pigs. 1, 2. Eusus (?) SUBTENUIS Heilprin ..... Pea reevee eaceee Rn ereoe nl eios oneaey eee 1. Dorsal view of specimen with nearly entees spire. 2 miles below Potomac Creek. 2. Ventral view of another specimen with perfect mouth. Two miles below Potomac Creek. . Fig. 3. TROPHON SUBLEVIS Harris ........... is Diceavaniie Rie Ho Ausretuee store et EEO View of fragment, with outlined restoration. 1 Toile northeast of Piscataway. Figs. 4, 4a. Fusus (?) INTERSTRIATUS Heilprin...... Saltestiba sei tca arin maeeae ear 135 4. Ventral view of specimen. 1 mile northeast of Piscataway. 4a. Dorsal view of same specimen. Figs. 5-8. STREPSIDURA SUBSCALARINA Hleilprin ........................ 136 5, 6. Ventral views of specimens. 2 miles below Potomac Creek. ie Potomae Creek. Acad. Nat. Sci. Phila. 8. Ventral view. 2 miles below Potomac Creek. 8a. Dorsal view. Same locality. Kis. 9. M@ELonGENA (?) POTOMACUNSIS M. Sps.....-....0.-2.++cssseeee- , IB Type. Potomac Creek. Acad. Nat. Sci. Phila. Lea Memoria! Coll. raya EOCENE, PLATE XxXIil. MARYLAND GEOLOGICAL SURVEY. MOLLUSCA—GASTROPODA. PLATE XXIII. Ines, Il, da, Wo, I CIDICIA MIARNADANIDIGUA Ts SID, op c0econa0 soon 0540 a00000000C 137 Ventral, dorsal and end views. 2 miles below Potomac Creek. IMGS, 2, Bele “ANOIDIGILA STDS ooo ba ces 50008005 050 con mp oS HoMa Leo OMS GO SDobcDOoDO IBS Ventral view. Crownsville. End view of the same specimen. IMG. SB, ILIFVAGTOSOS MRARBAMUIS (2) Comimacl Vaie.oococococoounccnscocc0004 139 Cast. Woodstock. Fig. 4. TUDICLA (?) sp. BA ii a hE Ashe a co eT Cast. . Aquia Creek. Fie. 5. MeruLA MARYLANDICA nm. Sp. ......-......- Sedge rosters Ses Seaersvedene « 139) Ventral view of type specimen. 2 miles below Potomae Creek. Fig. 6. CHRYSODOMUS ENGONATUS (Heilprin) ....... BRATS. nitca.t 8 140 2 miles below Potomae Creek. IDI aoe J efSI SI DIDO ENNIS] Oe ominous poppateonanenona somone aabapaootoaacoo dd besoc0cs 140 Cast. Upper Marlboro. MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE XxXill. Tr >) ‘ A MOLLUSCA—GASTROPODA. PLATE XXIV. PAGE Figs. 1, la. TRITONIUM SHOWALTERI (Conrad) ..................-.-.---- 141 1. Ventral view. 2 miles below Potomac Creek. la. Dorsal view of the same specimen. Ini, 2, IPvareieAMeOMGIUZ ene, COlmenGl eeasadehssaoncddosousuonaconueesooos 131 Ventral view with outlined restoration. Popes Creek. Figs. 3, 3a. PULGUROFICUS ARGUTUS Clark .......................--------- 142 Type specimen. Potomac Creek. Bice 4s daz sHuUSORTCUIEAY JUIVEINIS (\VVinuithielid)) eae. se ceeerieececiieiaeecas 143 4. Ventral view. 2 miles below Potomac Creek. 4a. Dorsal view of the same specimen. IB Ose pele NSRIUMAC (CR) RISTO = prspsittonsiesvoveper otedeus cet eyiches sirale¥es sey saclclret Nore vehehor actors mark pees 142 Body whorl. Popes Creek. LDitepe (oe) AR onan Coney a CAN aNSiom as aeomiore a crnicmain Score Glos omecaln id Ga dibancreo Omid olds Hou oto 138 Popes Creek. IPT, eo MIO) ION AOD (VAIIGIETCIN)) Socaséoccsccaccoucc0ccbnD0K0000C 144 Dorsal view. 1 mile southeast of Mason Springs. Misi 8:* Ov PRAWAS SMI (AN ArIGIa sa) pence arareis cate cee ais sche, aetna rece ei eye attoneneiee 144 Specimen with outlined restoration. Y¥ mile below Chapel Point. MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE XXIV. hee: MOLLUSCA—GASTROPODA. PLATE XXYV. Figs. 1, la, 2. CALYPTRAPHORUS JACKSONI Clark 1. Dorsal view of type. Sheckels Farm near South River. la. Ventral view of same specimen. (Figs. 1 and la are modified and corrected copies of the original figures in Bull. 141, U. 8. Geol. Survey.) 2. Dorsal view of large individual from same locality. Fig. 3. CALYPTRAPHORUS TRINODIFERUS Conrad ...................;. rd ees Dorsal view. 2 miles below Potomac Creek. Figs. 4, 4a. CALYPTRAPHORUS TRINODIFERUS (?) Conrad var............. 146 4. Ventral view. 1 mile southeast of Mason Springs. 4a. Dorsal view of the same specimen. IGS, ; @ APORISELMIS OTOMUNCIONISIS TM, SO. osdocc0ccc 50000052 00000080c008% 146 5. Ventral view of imperfect individual. Digitations restored from original of Fig. 6. 1 mile northeast of Piscataway. 6. External view of labrum of large individual from same locality. 217 MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE XXV. MOLLUSCA—GASTROPODA. PLATE XXVI. Ines, Ie}, AMGEN WOrMONM (COmIrael 5o>o00dcc00c000d0d000000c00000 Soret Ay, 1. Ventral view of specimen. Potomac Creek. la. Dorsal view of same specimen. 2. More elongate specimen from same locality. Specimen from same locality with stronger basal carina. Internal cast. Specimen showing the strong basal carina of the variety postmortoni of Harris. Tinkers Creek. Or HB co 278 ey MARYLAND GEOLOGICAL SURVEY. RNS | i MOLLUSCA—GASTROPODA. EOCENE, PLATE XXVI. PLATE XXVIII. PAGE Wigs. 1, la. TURRITELLA HUMEROSA Conrad.................-..--2.000:: 148 1. Ventral view. 1 mile southeast of Mason Springs. Figs. 2, 3. TURRITELLA POTOMACENSIS h. Sp. ....... 23 toutes eo Eee 149 Type specimens. Popes Creek. Huo we Vin SATEVANS OBRUDAU (Comrade paras eee ceca eee eee Popes Creek. J ENSASHY Gy eka On iain \ ton UH DU ELIS (S) Ohuere caoaecoca Sen coneopeoacseoeas educa. cdeccooas.4 Jax) 5. Small mass of tubes. 5a. End of same tube, enlarged. 6. Mass of tubes. Piscataway Creek. U. S. National Museum. 7. Short fragment of tube from same specimen, enlarged. MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE XXVII. pt tise | penn) ey oil! MOLLUSCA—GASTROPODA. PLATE XXVIII. PAGE Fig. 1. NATICA CLIFTONENSIS Clark ..... Benn AABN A oO en ae Pecbtajet moter . 150 Ventral view of type specimen. Clifton Beach. Figs. 2, 2a, 3. LUNATIA MARYLANDICA Conrad ............... Lishatetelete wi Cleo: Hiss. 459 CALwPTRAn sAAPHRmAN(Solamder)e geese sacar: sis se ada areyuyetayene pele 4. Dorsal view of specimen. -1 mile southeast of Mason Springs. 5. Cast of large individual. Figs. 6, 6a. LiTiIoPA MARYLANDICA Nn. Sp. ........... aware c het chars eee 5 ly) 6. Dorsal view of type specimen. 2 miles below. Potomac Creek. DIS SOA SOMARTUNE SP weno oqsceoe cede cite eeGie ena ee eSe eo meee LOS 7. Cast, as seen from above. Aquia Creek. 7a. Same specimen as seen from the side. Wigs. 8, 8a, 9, 9a. SCALA VIRGINIANA Clark ........... MER oocERE doth onbia 153 8. Ventral view of type specimen. Aquia Creek. U. 8. National Museum. 8a. Dorsal view of same specimen. 9. Ventral view of specimen. Potomac Creek. Acad. Nat. Sci. Phila. 9a. Dorsal view of the same specimen. TOME, NOs ISOUNGAN TROMOMONCIONISIS I, BD coonaccaccdanc00edd6040 cocdoonUEOOOR 154 Type specimen. 2 miles below Potomac Creek. Rio tllei SCAWACSESSILES Commad iyaccmancs cance cee Ake nie emer ce ee 154 2 miles below Potomae Creek. Bie) 12. 2 SCAGAD CARINATA: TEA caleiicie cle cing ciseionte areesee ee shetctom ech aldara mateo eneroe mel OLE 2 miles below Potomae Creek. 280 MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE XXVIII. MOLLUSCA—GASTROPODA. PLATE XXIX. PAGE Fig. 1. TURBONILLA POTOMACENSIS MD. SP. ........5.50.02020eees eee eee 155 2 miles below Potomac Creek. Ne ey MM GIEVAY INUAAWAINOITOUN TN, SOs Sooleooucooegeons coo ene cba dasoo boo on oouco JG Mouth of Paspotansa Creek. Fig. 3. ODOSTOMIA TRAPAQUARA (Harris) .......-..-.-.-ses sees eee eees 156 Potomac Creek. long, 4 INTEO© WEEN (UGB) cococcaadcccadcoo0v0so 90000 DOOGOOCOONGOS 156 Potomac Creek. 12s Gy) CausN CheAuninpN, (Comal) sdoooatcecoceasaccodsccscccdodon0e 157 Potomac Creek. Figs. 6, 6a. FISSURIDEA MARLBOROENSIS DN. SP. .........2-..-2 ee eee eee 158 6. Lateral view of type specimen. Upper Marlboro. 6a. Dorsal view of same specimen. Hiei DEN PALLUNG MIN RTS ERAN Galbloy essence eee lal 158 Popes Creek. 1a, IWasKaATeaONNE Wansisrisispoeseamisits| Coinravel goo6cc00escncacncadsecncaodas 159 Upper Marlboro. Fig. 9. CADULUS ABRUPTUS Meyer and Aldrich ........................ 159 Woodstock. 281 MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE XXIxX. MOLLUSCA—GASTROPODA AND SCAPHOPODA. PLATE XXX. PAGE Figs. 1, la. TEREDO VIRGINIANA (?) Clark..............+.....-.......-- 160 1. Lateral view enlarged as indicated. la. End view of same specimen. IMIG, By Bay Bo ‘ALIDTRIDIDYO) \WinXGHONAAKAN (Claw ooo 50cocecanGacedgoc7asb0caanKce 160 2. Lateral view of smal! fragment of tube. Woodstock. 2a. End view of same specimen. 3. Lateral view of another fragment. Woodstock. ines 4 dey ao, IPT NCONDOA, IMROVN. ((Coimegl) sc'cconcoessaccosugos 204 161 4. Dorsal view of cast. Fort Washington. 4a. Same specimen as seen from the left. 4b. Same specimen as seen from the right. WoO GASTRO CEUAIINIAS Os sere eereto eo asic) atel slo ioieistoriotesieie a aaciiotete ea cia en ey Ree eT ee aL ODL Cast of tube. Aquia Creek. 282 MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE XXX. MOLLUSCA—PELECYPODA. PLATH XXX. PAGE Migsy 1-5) IPANORHA EMONGAIAy Commad 7.4). oie ie idee a ee ae ee Ow 1. Left aspect of cast. Fort Washington. Left valve. Aquia Creek. 2a. Surface of same specimen. X 17 3. Right valve of Fig. 1. Left valve. Fort Washington. 5. Right valve. Fort Washington. 283 MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE XXXI. MOLLUSCA——PELECYPODA. PLATE XXXII. Figs. 1, la, 2, 2a, 2b. CORBULA SUBENGONATA Dall ...................... 163 1. Exterior of right valve. Popes Creek. la. Interior of same specimen. 2. Interior of left valve. Popes Creek. 2a. Exterior of same specimen. 2b. Hinge of same specimen, enlarged. Figs. 3, 3a, 4, 4a, 5, 5a, 6,.6a. CORBULA ALDRICHI Meyer ................ 163 3. Exterior of right valve. Evergreen, Va. 3a. Interior of same specimen. 4. Interior of left valve. Evergreen, Va. 4a. Exterior of same specimen. 5. Exterior of right valve. Evergreen, Va. 5a. Interior of same specimen. 6. Interior of young left valve. Evergreen, Va. 6a. Exterior of same specimen. Figs. 7, 7a, 8, 8a, 8b. CORBULA ONISCUS Conrad ....:................---- 164 7. Interior of right valve. Evergreen, Va. 7a. Exterior of same specimen. 8. Dorsal view of specimen. Evergreen, Va. 8a. Interior of right valve of same individual. 8b. Exterior of same valve. MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE XXXIl. MOLLUSCA—PELECYPODA. PLATE XXXII. PAGE Wig. 1. SOLEN LISBONENSIS (?) Aldrich ...............----------------:- 165 Fragment of left valve. % mile below Chapel Point. Figs. 2, 2a. TELLINA WILLIAMSI Clark .............. acm oma eros to coe 167 2. Exterior of left valve. Potomac Creek. 2a. Interior of same specimen. lies Sy MMBTPIAINWN AyaneIOMOARDN, Clee po5coocco0cuocoodsocouasapnnseSccocsoco] IGS Exterior of left valve. Hanoverville, Va. lores, 4i5 INUoon NOx Jens), (Comers). hogoasssceosanaceccoauucsoongbou co sccode illite) Exterior of right valve. Woodstock. Wigs. 5-9. MERETRIX SUBIMPRESSA Conrad ............-.----+2+--++-e+eeeee 170 5. Exterior of right valve. Acad. Nat. Sci. Phila. 5a. Interior of same specimen. 6. Dorsal aspect of complete individual. Acad. Nat. Sci. Phila. Exterior of left valve. Same collection. 8. Exterior of right valve. 8a. Interior of same specimen. 9. Interior of left valve. 9a. Exterior of same specimen. SY EOCENE, PLATE XXXill- MARYLAND GEOLOGICAL SURVEY. AG POD BEE GY: MOLLUSCA igs. 1, al la. Vigs. 2s 2a. 3a. Bye PLATH XXXIV. la. MERETRIX OVATA var. OVATA (Rogers) ........ Interior of right valve. West of Port Tobacco. Exterior of same specimen. 2-5. MERETRIX OVATA var. PYGA Conrad............ Exterior of right valve. Interior of same specimen. Interior of left valve. Exterior of Same specimen. Exterior of right valve. Exterior of left valve of young individual. 286 PAGE Jeeiar otc 168 MARYLAND GEOLOGICAL SURVEY EOCENE, PLATE XXXIV. MOI.LUSCA—PELECY PODA. Figs. la-1g. la. 1b. i@. . Exterior of Fig. 1b. . Dorsal aspect of complete individual. Same locality. . Interior of left valve. Same locality. g. Interior of right valve. PLATE XXXYV. DOSINIOPSIS LENTICULARIS GRO@ers)) ..........-.---------- Interior of left valve. Glymont. Interior of right valve. Exterior of Fig. la. Same locality. Same locality. 287 MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE XXXV. AM \ \ WE S MOLLUSCA——-PELECYPODA. PLATE XXXVI. PAGI Figs. 1-3. PROTOCARDIA LENIS Conrad ....... RRB Ono camonoenls ooaroeo 172 1. Exterior of right valve. 1 mile southeast of Mason Springs. la. Interior of same valve. 2. Interior of left valve. Pamunkey River, Va. Acad. Nat. Sci. Phila. 2a. Exterior of same valve. 3. Exterior of right valve from same locality and in same collection. Fig. 4. DIPLODONTA MARLBOROENSIS M. SP. ........---.--e+e src eeeeeceee 173 Exterior of left valve. Upper Marlboro. x 7/4 Figs. 5, 5a, 6, 7. DIPLODONTA HOPKINSENSIS Clark .....................- 174 5. Exterior of left valve. Evergreen, Va. 5a. Interior of same valve. 6. Exterior of right valve. Same locality. 7. Hinge much enlarged. 288 MARYLAND GEGLOGICAL SURVEY. EOCENE, PLATE XXXVI. l i MOLLUSCA—PELECYPODA. PLATE XXXVILI. Innes do les — IbiwCOMNPAS ANG EAANEN, Cllawelie GocadouoodoconosoabooobuoboaoOGOSOsOS 174 1. Exterior of right valve. Type specimen. Aquia Creek. U.S. Na- tional Museum. j la. Interior of same valve. Figs. 2, 2a. LUCINA ASTARTIFORMIS Aldrich ..................0.-2--eeees 175 2. Interior of left valve. 1 mile southeast of Piscataway. 2a, Exterior of same valve. Figs. 3, 3a, 3b. Luctina DARTONI Clark ......... Sond Ghousanacoobcdo IS 3. Interior of right valve of the type specimen. Wielka 3a. Exterior of same valve. 3b. Exterior of left valve of same individual. Riese 4275 TUCEN AL WHMBRT (Clark verre Gets otic toe ec leistotee erste ioe Seo erro retele 176 4, Hxterior of right valve of type specimen. Woodstock. 5. Interior of right valve of specimen. 1 mile southeast of Mason Springs. 6. Interior of left valve. Same locality. 7. Exterior of left valve of type specimen. Woodstock. HGS, th Cel, Os ItjecionyN Wwasmmine Clarke c5coscaopusdonsoconco0buc0s0cUbouN[S 176 8. Exterior of right valve of type specimen. Woodstock. 8a. Interior of same specimen. 9. Exterior of left valve of duplicate type. Same locality. 289 MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE XXXVII. \ \ MOLLUSCA—-PELECYPODA. PLATE XXXVI. q manga : ; PAGE é ¥ i GS, ty Ua. VATION TILAINTICO SMA Wane, mINGTA Comical sssccoccncsces HOS 1. Exterior of right valve. Upper Marlboro. Acad. Nat. Sci. Phila. x 9/10 . la. Interior of same valve. 290 EOCENE, PLATE XXXVIII. MARYLAND GEOLOGICAL SURVEY. Ah iy ir y ie YPODA. SCA—PELEC TOLLU N . PLATE XXXIX. Figs. 1, la. VENERICARDIA PLANICOSTA var. REGIA Conrad ....... Sea per 1. Exterior of left valve of individual figured on Plate XXXVIII. x 9/10. : | la. Interior of same valve. 291 MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE XXXix. MOLLUSCA—PELECYPODA. PLATE XL. PAG Figs. 1, 2, 3. WENERICARDIA PLANICOSTA var. REGIA Conrad ............ 178 1. Anterior view of compiete individual figured on Plates XXXVIII and XXXIX. Acad. Nat. Scei., Phila. 2. Exterior of left valve of very young individual. 3. Exterior of right valve of young individual. Figs. 4-6. VENERICARDIA POTAPACOENSIS ND. SP. ................-- sipatoeeehs Ss 179 4. Exterior of left valve of type specimen. West of Port Tobacco. 5. Exterior of left valve. 5a. Interior of Same specimen. 6. Exterior of right valve. 6a. Interior of same specimen. Figures 5 and 6 are from specimens in the Philadelphia Acad- emy of Natural Sciences. The locality of these specimens is in doubt, but they represent that form of V. potapacoensis which occurs typically in the Woodstock substage. HGS, i, Wale \WITRTAIRICUNRIOIUN, WUMRSALARIDIKCUN TM, SDs coococccsccoccnsuoonancs 179 7. Exterior of right valve of type specimen. 214 miles above Popes Creek. 7a. Interior of same specimen. OC 2 wile EOCENE, PLATE XL. MARYLAND GEOLOGICAL SURVEY. ) h.\\\e) \ Ys LN Ss aistoear a waned *n, ota Ny ry hy N i wi \ ’ Hay Al \ 38 ‘ yt) Nie s Wi), H)\\ q Y) } A yy oe, Yi, \\ = b = DOL I a S LL, al So to GLE JY Wd if me YY ~— a Z } SSS Zrgy = SAiyip = AAA as cae ert eno ee at ae, f ihre ‘ \ Ih Ave ty, ” GY ‘ ‘ 2 ms Y FS ¢ Ee? Gx 3) " ZF EEE a Wes ie - S\N 2 a C Sy) ‘ = AA? Vx NSE 2 % 4} \ SAY SSN S SRY S rs g ALTA Beit \ya SN ¥ BS AAP ANS Cj, f } Ay ; Mi Hl \ ‘ UN AO y y iY, / A ( LOANS iy | ‘ 1} S\ Yj; Hin? m/y'\\ \s . Dm, H ay Yi ADL! ) a \\ TAA HA \\\ SW TE, Mil f \ a(t Th , H i \} ) / ¢ HLL ‘ \\ S Hf yf i \ / i Wy \ AWRY . Be f \ i Ne . y fH noone. \\\ \ f ‘aaek \ Nigy \ \ Wr D. hae g ' A Kl \ %, { \ { i \\ UU PAN NN i AND aT H 7 Me i] | . i AN Ge ASV f)\ \\We oi] NYY Maly \ uy ae) TUR ONS aie |; A\ —— SS ——— os ?_—==S = = ———_S_ > 5 f SSS = = ————SSS==> —= ne _ SSS ——— ———$—J} Upp ol ih MOLLUSCA-—PELECYPODA. PLATE XLI. PAGE Figs. 1-8. CRASSATELLITES ALAEFORMIS (Conrad) ...................-.. 180 1. Exterior of the right valve of the type specimen of C. declivis Heilprin. Aquia Creek. U. SS. National Museum. (After Aldrich.) 2. Exterior of the left valve of the same. (After Aldrich.) 3. Exterior of right valve. Fort Washington. 3a. Interior of the same. 4. Interior of left valve. Fort Washington. da. Exterior of the same. 5. Exterior of left valve. 6. Exterior of left valve. Fort Washington. 6a. Interior of the same. 7. Interior of left valve. Fort Washington. va. Exterior of the same. 8. Exterior of right valve. Fort Washington. 8a. Interior of the same. 293 EOCENE, PLATE XLI. MARYLAND GEOLOGICAL SURVEY. MOLLUSCA—PELECYPODA. PLATE XLII. Figs. 1, 2a, 2b. CRASSATELLITES AQUIANA (Clark) ............. 1. Dorsal aspect of type specimen. Aquia Creek. 2a. Exterior of left valve of the same individual. 2b. Exterior of right valve of the same. His, 3. CRASSATERTITHS Amma (Conrad) 32. 55..5.5565s55° 2-2 =- Exterior of specimen. Hardesty. Janes, 4 Ae, (CRASS MuNMGIENOS SO, cooccouobododonG06d0 4 4. Exterior of right valve. Clifton Beach. 4a. Interior of the same. Tie, &, Agiisugiis) WAI IDAMADIOUA Cilrelke 5acsacaneccocgn0u00000000 Exterior of left valve of type specimen. Upper Marlboro. 294 PAGE 181 - 183 MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE XLII. MOLLUSCA—PELECYPODA. PLATE XLITI. Figs. 1, la, 2, 2a. CORALLIOPHAGA (ORYCTOMYA) BRYANT Clark.......... 183 1. Exterior of right valve. 1 mile southeast of Mason Springs. Ja. Interior of the same specimen. 2. Exterior of right valve of the type specimen. Pomonkey Neck. U.S. National Museum. 2a. Interior of the same specimen. Hic. 3. PHOLADOMYA MARYLANDICA Conrad .........5..-..--.+--+-++--+-- 184 Exterior of left valve. Fort Washington. Acad. Nat. Sci. Phila. Figs. 4, 5, 5a. MobDIOLUS ALABAMENSIS Aldrich ......................----- 185 4. Exterior of right valve. Mouth of Paspotansa Creek. 5. Exterior of right valve. Potomac Creek. 5a. Exterior of left valve of same individual. Ines, @, WIC UOMBS MONA LAOIOWS I, SDs ooaccocnsccccoccacacavsscodseuanc 186 Dorsal aspect of crushed specimen. Woodstock. Te Yo ITO PRIMAGA WUNEIDANIOIGA iM, SD cocosaoccosocdacgdaccandooudoNT 186 Hxterior of left valve of type specimen. Clifton Beach. 295 EOCENE, PLATE XLIIl. MARYLAND GEOLOGICAL SURVEY. i) jn | fi | i | ; j = Wy I y } PELECYPODA. MOLLUSCA PLATE XLIV. PAGE IDSs Il, digi, JaOwauA micaeroine CIB 555 s5455sdo0cns ass g5cm5 e361 sn Sos ccc soe IST 1. Exterior of left valve of type specimen. Hanover Co., Va. Acad. Nat. Sci. Phila. la. Interior of the same. IDES, 2, 2A, Bo ANINOMOUN NONE NTIGARADIEOUN Ts SID sa5dccascocc0cdc00c0n5 0500070006 187 2. Exterior of left valve. Popes Creek. 2a. Interior of the same. 3. Exterior of left valve. Same locality. Tiers ZL i, (Oy, JeiKoumony CleCoKouMAnjiaiNisiis; AMIGHENKElN Sgacocogoodcccb0uGon0co000000 188 4, Exterior of right valve. Popes Creek. The height of the orig- inal is 13.5 mm. instead of 11 mm. as the line indicates. 5. Exterior of left valve. Popes Creek. 6. Exterior of left valve of smaller individual. Same locality. Ries wiGrva, ib: PBCLEN DAMM Clarke Wiecncce ase cece a dee sere eee mL OS 7. Exterior of right valve of type specimen. Potomac Creek. va. Hinge of the same. xK 2 7b. Interior of the same. IMGs, &, Sel, Ieseaany goueansKomn Cllewelk socccdoccboncovgooobcc00uK. cK oon boOOOS 189 8. Exterior of left valve of type specimen. Potomac Creek. 8a. Interior of the same. Hose 9l ea -5 MPIC TEIN, WSO fevers eyes cie iieisis om sree mim BacNeTaS rae Oo EE ao 9. Interior of right a ee Potomae Creek. 9a. Exterior of the same. 296 MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE XLIV. MOLLUSCA—PELECYPODA. ous en xc, PAGE : OSTREA COMPRESSIROSTRA Shh ale Seiese nae Une arer Ipeiaen Senmam cont docse p64, LOO Lower valve of large individual. xX ¥% vi ete 297 MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE XLV- MOLLUSCA—PELECYPODA. PLATE XLVI. y 5 PAGE Higs. 1, 2) OSTRHA COMPRESSIROSTRA Say = 2-22. --9-- 42-90 see LOO 1. Lateral view of specimen figured on Plate XLV. x ; Fant 2a, 2b, 2c. Exteriors of young lower valves. . aa i X 208 MARYLAND GEOLOGICAL SURVEY. 4 pit, yy f ry Li, C 4. IZ 7 MOLLUSCA—PELECYPODA. EOCENE, PLATE XLVI. ca PLATE XDVITL. OsTREA COMPRESSIROSTRA Say Exterior of lower valve. da. Interior of the same. 1b. Lateral aspect of the same individual. Ob Beach. Exteriors of young upper valves. 299 EOCENE, PLATE XLVI l. MARYLAND GEOLOGICAL SURVEY. ~ \ ih mall LG fp a | SS SS ine WW, yaa S PELECYPODA. MOLLUSCA TEI) DOONIOUL, : it : _ PAGE Oicsada, lb. OsmRnAISENEAnHORMISe © omicaGuene rn ony sear ee acme ee) 192 la. Interior of lower valve. James River, Va. 1 1b. Exterior of upper valve of same individual with lower valve in position. : 300 MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE XLVIII. bik a \\ \ Ww y) a: j Mi Heh ie M MOLLUSCA—PELECYPODA. PLATH XULIX. Wigs. la-id. OSTREA SELLAEFORMIS Conrad .......................------- 192 la. Lateral view of specimen figured on Plate XLVIII. 1b, 1c, id. Exteriors of lower valves of young individuals. James River, Va. 301 ny MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE XLIX. Mi deoy (Sait { ATL PAW? iN t Pystceageassa eee Lapyyynnierin “e e\ x WSR RSS Ws FSS WA V = 2. 2 rs Odor to: 20 ay MOLLUSCOIDEA—BRYOZOA. PLATE LX. PAGE Figs. 1 and 2. MEMBRANIPORA RIMULATA Ml. Sp. ......-.-0++02+--200e ape c eilil 1. Surface of a specimen of the small-celled variety of this species. Upper Marlboro. xX 20 2. Surface of the type specimen. x Figs. 3 and 4. M@EMBRANIPORA SPICULOSA) m. Sp, ...-.--- ++ seer saocooe wile 3. Surface of a specimen, showing form and arrangement of zooecia and ovicells. Upper Marlboro. xX 20 4. Several zooecia of same, more highly magnified, Figs. 5 and 6. MEMBRANIPORA ANGUSTA 0. Sp. ................0-- sa0000 mula} 5. Surface of a specimen, showing connecting pores and oyicelle Upper Marlboro. xX 25 6. Portion of another and more worn specimen, without ovicells. x 20 Fig. 7. BIFLUSTRA ToRTA Gabb and Horn .................. 68000 aco o, ella 7. Portion of a fragment of the bifoliate zoarium of this species. Upper Marlboro. x 20 Figs. 8 and 9. REPTOFLUSTRELLA HETEROPORA Gabb and Horn..... Ree ones 8. Surface of the Eocene form. Upper Marlboro. x 20 9. One zooecium of same more highly magnified. Figs. 10 and 11. EscmAra ?? pierrATA Morton ........... ener gooong iks 10. Surface of a fragment of the Eocene form of this species. Upper Marlboro. x 20 11. Perfect zooecium of same more highly magnified to show the lunarium-like process of the lower border of the aperture. Higs. 12 and 13. CRIBRILINA MODESTA MN. Sp. ..............-.-------- so00 mlis 12. Portion of the type specimen of this species. Upper Marlbore: x 13. One zooecium of same more highly magnified. Fig. 14. CRIBRILINA CRASSULA Nn. Sp. ...... soo boneoo0cR0RS00000C sidtooonds Gls 14. Portion of the somewhat worn specimen deseribed. Upper } Marl- boro. x 20 Wigs. 15 and 16. LepPpRALIA LABIOSA D. Sp. ..................- senpereye no9000 Pel) 15. Surface of an average specimen. x 16. Two young zooecia, each with two avicularia and a semilunate area in the upper portion of the apertural rim. x 20 Figs. 17 and 18. MUCRONELLA ASPERA Nn. Sp. ........... oooonONOnCE Sopooa mel 17. Surface of a specimen. Upper Marlboro. xX 20 18. A few zooecia of another specimen. xX 20 Bios, 19 Vand 20) UN ULUIES | RE VIS AMIS O smieiereKeleleletetels6)(+ ler siclslels iol ielerels cdo0 wie 19. Portion of front surface of the specimen described. 2 miles below Potomae Creek. xX 25 20. Portion of dorsal surface of same. xX 20 312 MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE LX. MOLLUSCOIDEA—BRYOZOA. PLATE LXTI. PAGE Wiel, THRAGRVADIND YON SINAN) TILNINDG pe cceunaucbanesoesbonsodasbecs 232 Evergreen, Va. x 5/3 Ione 24 “IDOEUONGD) SHINS) Sooesdccoqcnoacc 15) Ne eeloses ores te volte oats Sto tesla OER .. 232 Potomac Creek. MGS Se s8az = EN AGE BNE TUM SOS panes fore valtn oka e A eveveve set ateitrenovarehe ieleieics ane tere oem Reel 222 3. Upright view of corallum, height 12 mm. 1 mile southeast of Piscataway. ; 3a. Calicular view, greater diameter of calice, 15.5 mm. Figs. 4, da, 4b. TURBINOLIA ACUTICOSTATA Vaughan..................-. 223 4. Upright view of corallum, height 6.5 mm. Popes Creek. 4a. Calicular view, diameter of calice, 3 mm. 4b. Margins of the costz of another specimen enlarged. Figs. 5 to 8. TROCHOCYATHUS CLARKEANUS Vaughan.................... 225 5. Upright view of a specimen, height 12.5 mm. 5a. Calicular view of the same, greater diameter of calice, 7.75 mm. 6. Upright view, height 10.5 mm. 7. Upright view of another specimen, height 10 mm. 8. Upright view of a fourth specimen, height 9.5 mm. Figs. 9, 9a, 9b. PARACYATHUS MARYLANDICUS n. Sp. ............ Eopaeusines Be 8) 9. Upright view of corallum, height 5 mm., 1 mile northeast of Piscataway. 9a. Coste enlarged. 9b. Calicular view, greater diameter of calice, 5.75 mm. Figs. 10, 11. BALANOPHYLLIA DESMOPHYLLUM M.-E. and H......... erst 10. Upright view, height 23 mm., 1 mile southeast of Mason Springs. 11. Upright view of another specimen, height 26 mm. Same locality. Figs. 12 to 14. HKUPSAMMIA ELABORATA (Conrad) ............ G006d00 so09 Cee) 12. Upright view of a specimen, height 17.5 mm. 13, 13a. Conrad’s type (from Alabama), length of corallum, 13 mm.; greater diameter of calice, 12 mm. 14, i4a. An unusually slender specimen; height of corallum, 15.5 mm.; greater diameter of calice, 9.5 mm. Potomac Creek. Figs. 15, 15a, 15b. HuUPSAMMIA CONRADI Vaughan...... states ous ey nagege somoo Call Conrad’s type of Turbinolia pileolus (not Turbinolia pileolus Fich- wald). Height of corallum, 11 mm.; greater diameter of calice, 13mm. Acad. Nat. Sci. Phila. 313 —-~ MARYLAND GEOLOGICAL SURVEY. ECHINODERMATA AND COELENTERATA. EOCENE, PLATE LXI. PLATE LXII. 2 PAGE ln, Wl, ALSSAMOIDATEIOA GiRAmomny Cl Oirlonenmyy ooocc00csccasg0cc0vecdDocoudndES 233 1 mile northeast of Piscataway. xX 50 ie, 2, IMSXTOMAITA SACTIINUILA IDSC ooooossoccaccsgcocccovgcsdo0ne 234 Upper Marlboro. x 50 pigs @, “ESTIMA SORANEUIAMA CVOMDIGIMY oscossoscosuacaupasocosecs 234 Brooks Estate near Seat Pleasant. x 50 Terkers Als | SUEUR ONLI CUWAY IClbyAIRIKOL BBN SaaS onebedonomsoooonod soos aoeadoouC 235 Type specimen. Woodstock. x 50 nS, GH, INODOSARIDN Aimmanis) (GMO OI@INW)) ocossecssdeocccvsbesonup ono a00KG 236 Woodstoek. x 10 Hig. 6. NODOSARIA BACILLUM Deframce ...................-.-+--s--seee 236 3 miles west of Leeland. x 10 Fig. 7. NODOSARIA COMMUNIS (G’Orbigny) ........................--.-0- 237 1 miles northeast of Piscataway. x 24 Fig. 8. NODOSARIA CONSORBRINA var. EMACIATA (Reuss) ...........-4-- 238 Upper Marlboro. x 10 Fig. 9. NODOSARIA SANDBERGERI (Reuss) .......................-----0- 238 Upper Marlboro. xX 24 ie, 10, NODOEARIA OBI WA, (ILMMME) socodcoogauocodcocoonanbesooounvoc 239 Upper Marlboro. x 10 314 MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE LXIl. PROTOZOA—FORAMINIFERA. PLATE LNXIII. PAGE Tene, tl, \WANGHENTOREIONN. Tiatetoiio (CILMI) ooqg5a0cd505000005000550005500006 240 Brooks Estate near Seat Pleasant. x 50 Figs. 2, 3. MARGINULINA CosTATA (Batsch) .............:.... agers ele 240 2. Large individual from Upper Marlboro. K 24 3. Smaller individual from same locality. x 50 lie, 45 (CRIS MIRON, CHA CIOs, 5aaccosonsavnnsob0boosecuaeaouCEK 241 1 mile northeast of Piscataway. x 24 Hic bse CRISE TIE ARWAG ROMAUL UID ACT (Hamnanceks)pei a rcilecen seiiecl eerie 242 1 mile southeast of Mason Springs. ar Nie, (5 (ChepiSsariicse/ NI IVAIONUNIDAN (Iexonmimemmeumim)) 5 5a0ceacacooncocdcucnc0undd 243 Woodstock. x 24 Fig. 7. POLYMORPHEINA AUSTRIACA (d’Orbigny) .....................-- . 244 Woodstock. x 50 Figs. 8, 9. POLYMORPHINA COMMUNIS (d’Orbigny) ....................-+-- 24-4 8. Woodstock. x 50 9. Upper Marlboro. x 50 Fig. 10. POLYMORPHINA COMPRESSA d’ Orbigny .......................- 246 Woodstock. x 40 Fig. 11. POLYMORPHINA ELEGANTISSIMA Parker and Jones.............. 247 Woodstock. x 50 Ihikeh IPS ARorewavionmenionyn (nusneyy (Cl(OieloyKenmh)) agooeedoqdoon4sbedcccG000000¢ 248 Brooks Estate near Seat Pleasant. x 50 Fig. 13. POLYMORPHINA LACTEA (Walker and Jacob) ..................- 248 Upper Marlboro. x 50 Big. 14. POLYMORPHINA PRABLONGA Terquem ....................+..-.- 249 Woodstock. x 32 Migs. 15, 16, 16a. GLOBIGERINA BULLOIDES d’Orbigny..................... 250 Well at Chesapeake Beach at 90-92 feet. x 50 315 MARYLAND GEOLOGICAL SURVEY. EOCENE, PLATE LXIll. PROTOZOA—FORAMINIFERA. PLATE LXIV. PAGE Mie. il, IDUSCORIIMUA TESTE OME (ClOromeIMy)) sosesaccenanoncanacoocaedues 251 Woodstock. xX 62 Fig. 2. DISCORBINA TURBO (d’Orbigny) .....................- seadoeo one. eoul Upper Marlboro. X 62 Fig. 3. TRUNCATULINA LOBATULA (Walker and Jacob) ................. 252 Upper Marlboro. xX 62 i Fig. 4. TRUNCATULINA UNGERIANA (d’Orbigny) ......................-- 253 Upper Marlboro. x 30 ig, 4, AWONUNTINPA ANEONOMDITS (IRSWSS) socoscocccsocccncccancsccuse0Kd 254 Upper Marlboro. xX 62 ibis. @ AUNOMUNIONUA CIROSSIDINUCOSMA (Evel!) scocgcous.c5sc0onsoneoaosns 254 1 mile northeast of Piscataway. X 62 Fig. 7. PULVINULINA EXIGNA var. OBTUSA Burrows ...........-...-+--+- 250 1 mile northeast of Piscataway. xX 62 Fig. 8. PULVINULINA SCHREIBERSII (d’Orbigny) ....................---- 256 Woodstock. xX 62 ING, QO, INONMOMIOVA ANIMES INCUWISS caoocasooogcnvesonop boson ongDebooonoOND 257 Woodstock. xX 62 Fig. 10. AMPHISTEGINA LESSONIL @’Orbigny ...................5.-..2000> 257 Woodstock. x 25 Figs. 11, lla, 11b. CARPOLITHUS MARYLANDICUS Nn. Sp. ................-- 258 11. Longitudinal section, showing position and shape of seed cell. Popes Creek. Jia. Entire fruit, side view. 1ib. Entire fruit, viewed at the apex. Figs. 12, 12a, 12b. CARPOLITHUS MARYLANDICUS var. RUGOSUS n. var..... 25: 12. Longitudinal section, showing position and shape of seed cell. Popes Creek. 12a. Entire fruit, side view. 12b. Entire fruit, viewed at the apex. 816 MARYLAND GEOLOGICAL SURVEY. 12a PROTOZOA—FORAMINIFER, AND PLANTAE. EOCENE, PLATE LXIV. INDEX A. Academy of Natural Sciences, Phila- delphia, 17. Accumulation of deposits, conditions of, 90. Alabama, Claiborne beds of, 27. Aldrich, T. H., 31, 75, 77, 79. * Alluvial deposits,” 25. Alluvial formation, 25. Annapolis, fossils from, 74, 76, 78, 80, 149, 178, 205. Appalachian Region, 21. Aquia Creek, section near, 68, 69. Aquia Creek, fossils from, 74, 76, 78, 80, 96, 98, 102, 104, 105, 107, 124, 131, 132, 138, 146, 148, 149, 151-154, 160- 162, 166, 172-174, 178, 181, 182, 186, 192, 193, 197, 201, 223, 225, 23 Aquia formation, 58, 85. Aquia formation, composition of, 59. Aquia formation, distribution of, 74, Aquia formation, description of, 59. Aquia formation, fossils from, 58, 68, COMialenie AMS mA Onn Geno Os Aquia formation, relation of to Chickasawan, 87. Aquia stage, species of, 86, 87. Arundel formation, 45. Ashley, S. C., 101. Atlantie Coast Province, distribution of Eocene in, 75. B. Bago, Re MM. Jir-, 16, 31, 93. Bailey, J. W., 31, 56. Bassler, Ray S., 31, 41, 121. Bells Landing substage, 37, 84. Bibbins, A., 30. Bognor rock, 92. Isxoyontlo, Ile (Coy B35 Be Bracheux sands, 37, 92. Broad Creek, section near, 73. Buhrstone, 37. - Buena Vista, fossils from, 74, 76, 78, 80, 138. h C. Case, H. C., 16, 93. Caleaire Grossier, 91. Chapel Point, fossils from, 75, 77, 79, 81, 145, 152, 160, 164, 166, 169, 177, 179, 193, 204: Character of Eocene deposits, 52. Charles Branch, fossils from, 75, 77, 79, 81, 201, 203. Charles County, 102. Chesapeake Beach, fossils from well at, 75, 77, 79, 81, 160, 161, 166, 247, 251, 254, 256. Chesapeake group, 47. Chester River, section on, 73. Chickasawan stage, 84, 87, 89. City Point, Va., 33, 34. Claiborne beds of Alabama, 27. Claibornian stage, 84. Clark, Wm. Bullock, 9, 21, 32, 93. Cleaveland, Parker, 25, 33. Clifton, fossils from, 74, 76, 80, 95-97, 100, 112, 123, 125, 138, 148, 149, 151, 152, 160- 164, 166, 170, 172, 176, 181, 183, 185-187, 191, 194, 197, 198, 20. Coastal Plain, 21. Coastal Plain deposits, general rela- tions of, 44. Collington, fossils from, 74, 76, 78, 80, 149, 170, 178, 181. Columbia formation, 49. Commission, 5. Conditions of accumulation of Eo- ecene deposits, 90. Conrad: TAY) 2%, 28) 29) 33, 34, 35, dil, 91. Contents, 11. Cope, E. D., 111. Correlation of deposits, 82. Correlation of deposits with those of Europe, 91. Cretaceous, 75, 77, 79, 81. Cretaceous, deseription of, 45. Crownsville, fossils from, 74, 76, 78, 80, 138. Oo 1D): Dall, W. H., 17, 35, 83, 92, 166, 167, 197. Dana, James D., 35. Darton, N. H., 30, 35, 40, 49, 57. Delaware, Eocene of, 49. Depth of sedimentation, 57. Distribution of species in Aquia for- mation, 74, 76, 78, 80. Distribution of species in Eocene, 75, 77. 79, 6. Distribution of species in Nanjemoy formation, 75, 77, 79, 81. Distribution of species, 73. Distribution of strata, 49. Dueatel, J. T., 28, 36. Ez. Eastman, Charles R., 16, 93. Ehrenberg, C. G., 56. Eocene deposits, composition of, 52. Eocene deposits correlated within Middle Atiantic Slope, 82. Eocene deposits, general character Clits 2B, Be Eocene deposits, general distribution of, 75. Eocene deposits, origin of, 54. Eocene deposits, strike and dip of, 53. Eocene deposits, thickness of, 54, 90. Eocene foraminifera, 31. Eocene formations correlated with Gulf states, 83. Eocene, first use in America, 27. Eocene of Middle Atlantic Slope, de- scription of, 46. Eocene strata, distribution of, 49. Eolignitic, 37. European equivalents, 91. Evergreen, Va., fossils from, 174, 232. F. Faunal stages, table showing, 58. Featherstonhaugh, G. W., 36. Finch, John, 25, 36. Fireman, Peter, analyses by, 53. Fontaine, W. M., 36. Formations, table showing, 58. Formations and faunal stages, 58. Fort Washington, 27, 31, 33. Fort Washington, fossils from, 74, 76, 78, 80, 104-106, 138, 148, 149, 151, 1o2, 161, 162, 166, 167, 170, 172, 179, 181, 185, 186, 191, 192, 197. 18 INDEX Fossils of Paspotansa substage, 63. Fossils of Piscataway substage, 61. Fossils of Potapaco substage, 65. Fossils of Woodstock substage, 66. Fredericktown, fossils from, 74, 76, 78, 805 Tie. E78; 193k lone G. General stratigraphic relations, 44. Geographical distribution of species, on Geological criteria, 89. Geological distribution of species, 73. Geological divisions, 15. Gilman, Daniel C., 5. Glymont, 61. Glymont, fossils from, 74, 76, 78, 80, 107, 148, 149, 151, 152, 162, 163, 165, 170; 172, 176, 181, 182186. 1910 Wose LOT Glymont, section at, 68. Greensand, origin of, 55. Greggs Landing substage, 84. Grimesville, fossils from, 74, 76, 78, 80, LO; ies, 192s d Gulf province, distribution in, 75. H. Hanover county, Va., fossils from, 188. Hardesty, fossils from, 74, 76, 78, 80. 141; 148. 151, 162, 170, 172 178, 182: 191, 195, 197. Harris, G. D., 17; 30, 37 166; 167, 197. Harrisons Landing, fossils from, 74, 76, 78, 80, 172. Hatchetigbee substage, 84. Hayden, Hl He, 25537. Heilprin, A., 37, 91. Heinrich, O. J., 38. Hering, Joshua W., 5. Higgins, James, 30, 38. Hilgard, E. W., 48. Hills Bridge, fossils from, 75, 77, 79, 81, 160, 165, 194. Historical review, 24. Hollick, Arthur, 16, 93. Hotchkiss, Jed., 38. Hunter, H. C., 17. rE Illustrations, List of, 13. Introduction, 21. Iterson, F. von, 17. : ia i INDHX 319 J. Jacksonian, fossils from, 75, 77, 79, 81. Jacksonian stage, 84, 85. Jaekel, O., 104. James river, deposits of, 29. Johns Hopkins University, collections of, 17. Johnson, C. W., 17. K. Kalm, Peter, 24, 38. Koken, E., 114, 115. L. Lafayette formation, 47. La Plata, fossils from, 75, 77, 79, 81, 180. Lea, Henry C., 39. Lea, Isaac, 27, 39, 91. Leeland, fossils from, 74, 76, 78, 80, ifsal, Wil, Wry, Z0w,. Bar Leidy, Joseph, 101. Letter of transmittal, 9. Lignitic of Gulf, 37. Liverpool Point, fossils from, 74, 76, 78, 80, 95, 100, 103, 104, 105-107, 132, 136, 148, 149, 151, 152, 160, 164, 170, On MSie «M82 1She 192) 197, 2018 London elay, 27, 33, 91. Lower Chickasawan stage, 85. Lower Chickasawan stage, fossils TPO, iy Try Ty thls Lower Claibornian, 85. Lyell, Chas., 29, 39, 91. Lyons Creek, section near, 72. M. MeConnell, J. C., 17. McGee, W J, 30, 40, 49. Maclure, William, 24, 39. Manasquan formation, 205. Marlboro clay, 65. Marlboro Point, fossils from, 226, 231. Marls, analyses of, 53. Marsh, O. C., 111. Marshall Hall, 162. Martin, George Curtis, 21, 93. Maryland, Eocene in, 50. Mason Springs, fossils from, 74, 76, 78, 80, 125-127, 129-131, 140, 144, 146, 148, 149, 151-153, 155, 161-163, 166, 17, 473, 176, 181, 184, 186, 191, 197, 299.31, 237, 243. Matawan formation, 45. Mattawoman Creek, fossils from, 74, 76, 78, 80, 106, 172, 176, 181, 182, 191. Maury, M. F., 39. Meyer, O., 91. Middle Atlantic Slope, 21. Midwayan stage, 84, 85. Miller, S. A., 40. Monmouth formations, 45. Morton, S. G., 26, 27, 40. Mount Misery, déposits at, 52. Mullica Hill, N. J., 214, 215, 216. Murchison, R. I., 29, 41. Murray & Renard, 55. N. Nanafalia substage, 84. Nanjemoy Creek, 66. Nanjemoy Creek, fossils from, 75, 77, 79, 80, 125, 145, 160, 164, 165, 169, 179, 199, 203. Nanjemoy Creek, section near, 70. Nanjemoy formation, 47, 58, 69, 70, 71, 72, 85. Nanjemoy formation described, 64. Nanjemoy formation, relations to Chickasawan, 89. % Nanjemoy stage, species of, 87, 88. Neocene deposits described, 47. New Jersey, greensands of, 28. Niekles, John M., 31, 41. Noetling, F., 104. O. Origin of Eocene materials, 54. Ostrea sellaeformis zone, 83. Oxen, section at, 71. RP Paleontological criteria, 84. Pamunkey formation, 35, 57. Pamunkey Group, 58. Pamunkey river, Va., 35. Pamunkey river, Va., fossils from, 232. Paspotansa Creek, fossils from, 74, 76, (Sy AO, Wabi aay alate) aya aly), IG) 170; 173, 178, 181): 186, 19, Toa 1977. Paspotansa stage, 58, 69, 72, 73, 74, 75, 76, vt. 78, 79, 80, Sil. Paspotansa stage described, 62. Paspotansa stage, distribution, 74, 80. Paspotansa stage, fossils of, 63. Patapseo formations, 45. 320 INDEX Patuxent formations, 45. Patuxent river, section on, 72. Piedmont Plateau, 21. Pierce, James, 26, 41. Jem lSlormye dale VANS alii Pisgah, fossils from, 74, 76, 78, 80, 172, 191. Piscataway, 33, 34. Piscataway, fossils from, 75, 77, 79, 81, eH wes, eG, Ue. Weil, sR, lee IEG. 147-149, 151, 157, 159-165, 169, 171- 173, 175, 176, 178, 180, 181, 185, 188, 191, 193, 195, 197, 201, 202, 223, 226, 227, 233, 242, 255, 256. Piscataway, section at, 72. Piscataway Creek, fossils from, 74, 76, 78, 80, 150. Piscataway stage, 58, 68, 69, 71, 73, 74, Ty WO. Tis Ws 7) EO, tal. Piscataway stage described, 69. Piscataway stage, distribution in, 74, 80. Piscataway stage, fossils of, 61. Pleistocene deposits described, 48. Pomonkey Neck, fossils from, 74, 76, 78, 80, 132, 133, 143, 184. Popes Creek, fossils from, 75, 77, 79, Si OZ OGE HOS dalses 23a 28enal3 0; 131, 136; 138, 139, 142, 146, 149, 150, TSO e ly oa) Oeole eal Ga —16 OamelG Opmalerale U7, Uy, UNOS Wee, UO, WO, ISB, iss, 187, 188, 192, 194, 195, 197, 198, 199, 202, 203, 210, 225. Popes Creek, section near, 70, 71. Post Eocene, fossils from, 75, 77, 79, 81. Port Tobacco, 32, 66. Port Tobacco, fossils from, 75, 77, 79, 81, 115, 124, 125, 131, 145, 151, 152, 159, 160, 179, 193, 201. Potapaco stage, 58, 65, 69, 70, 72, 75, 77, 79, 81. Potapaco stage described, 65. Potapaco stage, distribution in, 75. Potapaco stage, fossils of, 65. Potomac Creek, 75. Potomac Creek, fossils from, 74, 75-80, 100, 124-126, 129, 131-134, 136, 137, 140, 141, 144, 146-148, 150-157, 162, HGS) LOO i OS muie sm OnmOnmmlis ees 186, 189-191, 193, 195, 197, 201, 218, 220, 220, Aol, Gar, cole Potomac Creek, section near, 69, 70. Potomac Group, 45. Potomac River section, 67. Potomae river, section on, 67. Preface, 15. Probst, J., 104. R. Ranecoeas formation, 45. Raritan formation, 45. Reedy Run, fossils from, 74, 76, 78, 80, 170, 172, 182, 191, Rogers, H. D., 28, 42. Rogers, William Bs) 27, 28, 41, 42, 51. Rolph’s Landing, fossils from, 74, 76, 78, 80, 148, 150, 162, 178, 178, 181, 195, 197. Rolph’s Landing, sections near, 73. Ruffin, Edmund, 42. 8. Say, Thomas, 26, 42. Schuchert, Charles, 16, 204. Schopf, Johann David, 24, 42. Seat Pleasant, fossils from, 74, 76, 78, 80, 120, 148, 149, 162, 170, 172, 181- 183, 192, 235, 238, 240, 254. Seat Pleasant, section near, 71. Secondary formation, 25. Section at Glymont, 68. Section near Lyons Creek, 72. Sections near Potomac Creek, 69-70. Section of Potomae river, 67, 68. Section of western portion of bluff at. Aquia Creek, 69. Sedimentation, depth of, 57. Severn river, fossils from, 74, 76, 78, 80, 179, 191, 232. Severn river, section near, 13. Shark River formation, 205. Shattuck, G. B., 30, 49. Silvester, R. W., 5. Smith, John Walter, 5. Southeast Creek, fossils from, 74, 76, 78, 80, 188, 189. South River, fossils from near, 74, 76, 78, 80, 145, 148-150, 172, 173, 178, 179, 181, 183, 191-193, 195, 197, 200, 202, 232. South River, section at, 73. Species, distribution of, 73. Stratigraphical and paleontological characteristics, 57. Strike and dip of Hocene deposits, 53. Suessonian, 92. Swan Creek, fossils from, 74, 76, 78, 80, alghile INDEX 321 A Table of correlation, 85. Table showing formations and faunal stages, 58. Table showing geographical and geo- logical distribution of species, 73. ‘Table showing local and general dis- tribution of Eocene species, 74. Timber Creek, N. J., 208, 214, 215, 216, 219. Tertiary formations, 22, 25. Thanet sands, 37, 92. Thickness of Eocene deposits, 54. Thrift, fossils from, 75, 77, 79, 81, 168, 197. Thrift, section near, 72. Tinkers Creek, fossils from, 74, 76, 78, 80, 148, 149, 162, 191. Transgression of Hocene deposits, 83. Transmittal, letter of, 9. Tuomey, M., 43, 123. Turritella rock, 64. Tyson, Philip T., 30, 43. U. Uhler, P. R., 30, 43. Wilrieh, iH. OF 165) 81, 93" U. S. Geological Survey, 17. U. S. National Museum, 17. Upper Chickasawan, 85. Upper Chickasawan, fossils from, 75, 77, 79, 81. Upper Claibornian, 85. Upper Marlboro, 31, 32, 34. Upper Marlboro, fossils from, 74-81, 117, 118; 1205 121, 124; 136, 140, 143°, 145, 148-152, 155, 157-162, 164, 165, 169-176, 178, 180, 181, 183, 186, 188, 189, 191-195, 197, 199, 200, 202, 203, 206-208, 210-216, 218-222, 231-234, 237-239, 241-243, 249, 252-254. Upper Marlboro, section near, 72. We Van Rensselaer, J. 26, 43. Vanuxem, Lardner, 26. Vaughan, T. Wayland, 16, 43, 81, 93. Vincentown, N. J., 121, 206, 208, 209, Ply, Gila. Oils, BiG, B2Xx0, Zee Virginia, Eocene of, 51. W. Wades Bay, fossils from, 74, 76, 78, 80, 181, 186, 191. Washington, D. C., 35. Washington, fossils from near, 163. Willis, Bailey, 40. Williams, G. H., 40. Winchester, fossils from, 74, 76, 78, 80, 162. Woods Bluff, Ala., 227 Woods Bluff substage, 84, 223. Woodstock, fossils from, 75, 77, 79, 81, 100, 105, 106, 109; 115, 122, 124) 125, sal. Is33}5 aS), BG, ae, lea, ALGO), UGB=UHo, als, alieal, ale Illy, alr) 184-187, 189, 192, 195-199, 201-203, 223, 230, 237, 243, 244, 246, 247, 249, 201, 253, 256-258. Woodstock, section at, 70. Woodstock stage, 58, 66, 70, 71, 75, 77, 79. Bil. Woodstock stage described, 66. Woodstock stage, distribution of spe- eies from, 75, 77, 79, 81. Woodstock stage, fossils of, 66. Woodstock, Va., 31. Woodward, A. S., 98, 101. Woodward, Smith, 104. Wyman, Jeffries, 111, 112, 115. E PALEONTOLOGICAL INDEX A. Actaeonidae, 123. Actinopterygii, 110. Acteon metanellus, 156. Aetobatis, 107. Aetobatis arcuatus, 74, 75, 102, 265. Aetobatis profundus, 102. Amphistegina lessonii, 67, 80, 81, 257, 316. Angelus, 166. Anomalina ammonoides, 63, 80, 81, 254, 316. ; Anomalina grosserugosa, 63, 254, 316. Anomalodesmacea, 184. _ Anomia marylandica, 78, 79, 187, 295. Anomia megeei, 187, 295. Anomia ruffini, 187. Anomiidae, 187. Anthozoa, 222. Aporrhaidae, 146. Aporrhais potomacensis, 63, WHS, Bitte Area onochela, 196. Area rogersi, 196. Areidae, 194. Artemis lenticularis, 171. Arthropoda, 74, 75, 116. Aspidobranchiata, 157. Astarte marylandica, 63, 72, 78, 79, 183, 294. Astartidae, 183. Asterospondyli, 102. Athleta tuomeyi, 130. Aviecula limula, 194. FOL Sh, 76, 77, B. Bairdiidae, 116. Balanophyllia desmophyllum, 63, 80, 81, 85, 86, 227, 313. Berenicea, 206, 208. Bicrisina gaudryana, 207, 208. Biflustra disjuncta, 212. Biflustra torta, 63, 80, 81, 214, 312. Brachiopoda, 78, 79, 203. Bryozoa, 78, 79, 80, 81, 205. Buecinidae, 136. Byssomya petricoloides, 186. Bythocypris parilis, 63, 74, 75, 117, 268. Bythoeypris subaequata, 63, 74, 116, ily, Pas. C. Cadulus abruptus, 59, 66, 76, 77, 85, 86, 87, 88, 89, 159, 281. Cadulus bellulus, 159. Cadulus subeoarctatus, 160. Calliostoma sp., 63, 76, 77, 157. Calyptraea aperta, 59, 76, 77, 85, 86, 88, 89, 152, 280. Calyptraea aperta, 152. Calyptraea trochiformis, 152. Calyptraphorus jacksoni, 63, 72, 76, 77, IDE, Te Calyptraphorus trinodiferus, 59, 65, 76, 77, 85, 86, 88, 145, 277. Calyptraphorus trinodiferus (?) var., 76, 74, 146. m Calyptraphorus velatus, 146. Calyptrophorus. See Calyptraphorus. Caneellaria graciloides, 128. Cancellaria graciloides var., 63, 74, 75, 85, 86, 128, 273. Caneellaria (Narona) potomacensis, 63, 74, 75, 129, 273. Cancellaria parva, 129. Cancellaria ulmula, 129. Caneellaria sp., 63, 74, 75, 129, 273. Caneellaridae, 128. Caneroidea, 116. Capulidae, 152. Carcharias, 109. Carchariidae, 108. Carcharodon, 107. Carcharodon acutidens, 108. Carcharodon angustidens, 108. Carcharodon auriculatus, 66, 74, 108. Careharodon econtortidens, 108. Carcharodon erassidens, 108. Carcharodon rectus, 108. 324 PALEONTOLOGICAL INDEX Cardiidae, 172. Cardita planicosta, 178. Carditidae, 172, 177. Cardium (Protocardia) lenis, 172, 173. Cardium nicolletti, 172. Caricella pyruloides (?), 60, 74, 75, 85, 86, 131, 273. Caricella, 131. Caricella sp., 62, 131. Carpolithus marylandicus, 67, 80, 81, 258, 316. Carpolithus marylandicus var. rugo- sus, 67, 80, 81, 258, 316. Caryophyllidae, 225. Cassididae, 144. Cassidaria brevidentata, 144. Cavaria dumosa, 63, 78, 79, 208, 311. Cavaria ramosa,; 209. Cephalopoda, 74, 75, 122. Ceriopora micropora, 65, 80, 81, 210, eels Cerioporidae, 208. Cestraciontidae, 102. Cheloniidae, 97. Chilostomata, 211. Chrysodomus engonatus, 63, 76, 77, 85, 86, 140, 274. Cidaridae, 232. Cidaroida, 232. Clydonautilidae, 122. Coelenterata, 80, 81, 222. Compressidens, 159. Coprolites, 96, 115, 262. Coralliophaga bryani, 63, 78, 79, 183. Coralliophaga (Oryctomya) bryani, 183, 295. Corbula alabamiensis, 163. Corbula aldrichi, 76, 77, 85, 86, 88, 163, 284. Corbula nasuta, 163. Corbula oniscus, 59, 67, 70, 76, 77, 85, 87, 88, 89, 164, 284. Corbula (Aloidis) oniseus, 164. Corbula sp., 71. Corbulidae, 163. Corbula subengonata, 59, 67, 71, 76, 77, 85, 86, 87, 163, 284. Crassatella alaeformis, 180. Crassatella alta, 182. Crassatella capri-cranium, 180. Crassatella declivis, 180. Crassatella palmula, 180. Crassatella protexta, 180. Crassatellites alaeformis, 60, 61, 64, 68, 69, 71, 72, 73, 78, 79, 180, 182, 183, 293. Crassatellites alta, 63, 78, 79, 182, 294. Crassatellites aquiana, 60, 61, 78, 79, 181, 294. Crassatellites palmula, 181. .Crassatellites sp., 78, 79, 183, 294, Crassatellitidae, 180. Cribrilina crassula, 63, 80, 81,-218, 312. Cribrilina modesta, 63, 80, 81, 278, 312. Cribrilinidae, 218. Cristellaria acutauricularis, 241. Cristellaria crepidula, 242. Cristellaria cultrata, 243. Cristellaria excisa, 241. Cristellaria gibba, 63, 80, 81, 2417, 315. Cristellaria pulchella, 241. Cristellaria radiata, 66, 80, 81, 243, 315. Cristellaria rotulata, 63, 80, 81, 242, 315. Cristellariae, 240. Crocodilia, 95. Crocodilidae, 95. Crustacea, 116. Cryptodira, 97. Cucullaea gigantea, 59, 61, 64, 69, 71, 72, 73, 78, 79, 85, 86, 87, 88, 196, 304, 305, 306, 307. Cucullaea gigantea var., 196. Cuecullaea onochela, 196. Cucullaea rogersiana, 196. Cucullaea transversa, 196, 197. Cyclostomata, 205. Cylichna aldrichi, 125. Cylichna venusta, 59, 70, 74, 75, 124, 271. Cypraea smithii, 65, 76, 77, 85, 88, 144, 276. Cypraeidae, 144. Cythere angusticostata, 121. Cythere deshayesiana, 120. Cythere edwardsi, 121. Cythere hebertiana, 120. Cythere macropora, 121. Cythere marylandica, 60, 74, 75, 119, 268. Cythere punctata, 120. Cythere thierensiana, 120. Cythere triangularis, 119. Cythere trigonula, 119. Cytherea lenis, 168. Cytherea lenticularis, 171. Cytherea liciata, 168. ’ PALEONTOLOGICAL INDEX 325 Cytherea ovata, 168. Cytherea pyga, 169. Cytherea subimpressa, 170. jJythereis bassleri, 63, 74, 75, 120, 268. Cytheridae, 119. Cytheridea debilis, 122. Cytheridea intermedia, 122. Cytheridea milleri, 122. Cytherella compressa, 116. Cytherella londinensis, 118. Cytherella marlboroensis, 63, 74, 75, 117, 118, 268. Cytherella ovata, 118. Cytherella submarginata, 63, 74, 75, 118, 268. Cytherellidae, 117. Cytheridea perarcuata, 74, 75, 121, 268. D. Decapoda, 116. | Dentaliidae, 158. Dentalina affinis, 236. Dentalina badenensis, 237. Dentalina communis, 237. Dentalina consobrina var. emaciata, 238. Dentalina inornata, 237. Dentalina legumen, 237. Dentalina sandbergeri, 238. Dentalina subarcuata, 237. Dentalium minutistriatum, 67, 76, 77, 158, 281. Dentalium mississippiensis, 59, 76, 77, 19, 28. Dentalium thalloides, 159. Diadematidae, 232. Diadematoida, 232. Dione liciata, 168. Dione ovata, 168. Dione pyga, 170. Diplodonta hopkinsensis, 173, 174, 288. Diplodonta marlboroensis, 63, 72, 78, 79, 173, 288. Diplodonta ungulifera, 173. Diplodontidae, 173. Discorbina bertheloti, 67, 80, 81, 2951, 316. Discorbina turbo, 63, 80, 81, 251, 316. Discosparsa varians, 63, 78, 79, 2005, olales Doliidae, 141. Dosinia lenticularis, 171. Dosiniopsis lenticularis, 61, 68, 69, 71, R2.a76. 19.85. 8641 nla eae Dosiniopsis meekii, 171. Echinodermata, 232. Eehinoidea, 232. Egeria rotunda, 173. Elasmobranchii, 98. Ensuchia, 95. Escharidae, 219. Eschara digitata, 80, 81, 276, 312. Hseharipora, 218. Escharipora immersa, 219. Escharipora inerassata, 219. Escharifora typica, 222. Huelastes (?) sp., 61, 74, 75, 97, 262. HKulimidae, 156. Hupsammia conradi, 231, 313. EKupsammia elaborata, 60, 62, 80, 81, 85, 86, 229, 313. Eupsammia (?) pileolus, 231. F. Fascipora pavonina, 207. Fascipora subramosa, 63, 78, 79, 207, @alals Fasciporidae, 207. Fissurellidae, 158. Fissuridea marlboroensis, 63, 72, 76, 77, LoS, 281. Flabellum cuneiforme var. pachyphyl- lum, 223. Flabellum cuneiforme var. wailesi, 223% Flabellum johnsoni, 223. Plabellum sp., 80, 81, 222, 313. Foraminifera, 233. Fulgur argutus, 142. Fulguroficus argutus, 76, 77, 142, 276. Fulguroficus triserialis, 142, 1 Fusoficula juvenis, 63, 76, 77, 85, 86, 143, 276. Fusidae, 133. Fusus (Hemifusus ?) engonatus, 140. Fusus (?), 134. Fusus (?) interstriatus, 74, 75, 85, 87, 88, 135, 273: Fusus (Levifusus) trabeatus, 139. Fusus (Strepsidura) perlatus, 136. Fusus (Strepsidura) subscalarinus, 136. Fusus (?) subtenuis, 63, 74, 75, 85, 86, 134, 274. 326 PALEONTOLOGICAL INDEX Fusus trabeatus, 138. Fusus trabeatus (?) var., 76, 77, 139. G. Galeocerdo, 109. Galeocerdo latidens, 66, 74, 75, 109, 266. Galeocerdo minor, 109. Gastrochaena sp., 60, 76, 77, 161, 282. Gastrochaenidae, 161. Gastropoda, 74, 75, 76, 77, 123. Gibbula glandula, 60, 72, 76, 77, 197, 281. Globulina gibba, 248. Globigerina bulloides, 67, 80, 81, 290, ab Se Globigerinidae, 250. Glycymeris elongata, 162. Glyeymeris idoneus, 67, 70, 72, 73, 78, 79, 85, 86, 88, 194, 302. Gryphaea eversa, 193. Gryphaea vesicularis, 61, 193, 302. Gryphaea vomer, 193. Gryphaeostrea, 193. Gryphaeostrea vomer, 59, 72, 193. Guttulina austriaca, 244. Guttulina communis, 244. Guttulina nitida, 244. Gymnoglossa, 155. H. Hexacoralla, 222.. Hercoglossa (Enclimatoceras) ulrichi, 123. Hercoglossa tuomeyi, 71, 74, 75, 122, 268, 269, 270. , Heteropora (?) teeta, 63, 80, 81, 210, eilelem Heteropora (Multicrescis) parvicella, 209. le Idmoniidae, 207. Ischyrhiza (?) radiata, 112. L. Lagenidae, 236. Lamna, 103, 106. Lamna acuminata, 106. Lamna clayata, 105. Lamna compressa, 105. Lamna compressa (pars), 110. Lamna cuspidata, 105. Lamna elegans, 104, 105, Lamna (?) obliqua, 106. Lamnidae, 108. Latiarea idonea, 196. Latiarea onochela, 196. Latiarea transversa, 196. Latiarea gigantea, 196. Latirus marylandicus, 63, 74,75, 133, 273. Leda (Adrana) cultelliformis, 198. Leda ecliftonensis, 60, 78, 79, 200, 201, 308. Leda cultelliformis, 67, 70, 78, 79, 198, 308. Leda improcera, 64, 67, 78, 79, 199, 200, 308. Leda parilis, 72, 78, 79, 199, 309. Leda parilis var., 66, 78; 79, 200, 309. Leda parva, 67, 78, 79, 85, 86, 88, 197, 308. Leda pharcida, 201. Leda potomacensis, 64, 78, 79, 85, 88, 200, 308. Leda protexta, 200, 201. ‘Leda tysoni, 64, 78, 79,201, 309. Ledidae, 199. Lenticulites rotulata, 242. Lepralia labiosa, 63, 80, 81, 220, 312. Lepralia subplana, 63, 80, 81, 219, 311. Levifusus trabeatus (?), 66, 76, 77, 138. Levifusus trabeatus (?) var., 66, 76, 77, 85, 88, 89, 139, 275. Limopsidae, 195. Limopsis decisus, 195. Litiopa marylandica, 76, 77, 152, 280. Lithophaga marylandica, 61, 78, 79, 186, 295. Littorinidae, 152. Lucina aquiana, 60, 72, 78, 79, 85, 86, 174, 289. Lucina astartiformis, 65, 67, 78, 79, 85, 88, 175, 289. Lucina claibornensis, 177. Lucina dartoni, 64, 67, 78, 79, 175, 289. Lucina greggi, 174. Lucina sp., 78, 79, 177. Lucina uhleri, 59, 67, 78, 79, 85, 87, 88, 176, 289. Lucina ulrichi, 176. Lucina whitei, 64, 67, 78, 79, 176, 289. Lucinidae, 174. Lunatia eminula, 151. Lunatia marylandica, 59, 76, 77, 85, 86, 88, 89, 151, 280. Lunulites patelliformis, 217. PALEONTOLOGICAL INDEX 327 Lunulites regularis, 217. Lunulites reversa, 63, 80, 81, 217, 312. Lunulites semilunaris, 217. M. Malacostraca, 116. Mangilia (Pleurotomella) bellistriata 74, 75, 128, 272. Marginulina, 240. Marginulina costata, 63, 80, 81, 240, 315. Melongena (?) potomacensis, 63, 74, 75, 136, 274. Melongena subecarinata, 137. Membranipora angusta, 63, 80, 81, 213, Bile. . Membranipora lineata, 213. Membranipora perampla, 212. Membranipora rimulata, 63, 80, 81, 2/17, 312. Membranipora spiculosa, 63, 80, 81, 912, 214, 215, 312. Membraniporidae, 211. Meretrix lenis, 67, 76, 77, 168, 285. Meretrix liceata, 168. Meretrix nuttalliepsis, 169. Meretrix ovata, 168. Meretrix ovata var. ovata, 64, 65, 76, 77, 168, 286. Meretrix ovata var. pyga, 60, 61, 68, 69, 7A, 72,73, 182 29 Soe SS. 269: 286s Meretrix pyga, 170. Meretrix subimpressa, 67, 70, 71, 78, 79, 85, 88, 170, 286. Mesalia obruta, 70, 71, 72, 76, 77, 85, 87, 88, 149, 279. Metula marylandica, 63, 76, 77, 159, 215. Miecroporidae, 216. Mitra marylandica, 63, 74, 75, 132, 273. Mitra pomonkensis, 63, 74, 75, 132, 273. Mitra potomacensis, 70, 71, 74, 75, 133, 273. Mitra sp., 132. Mitsikurina, 1€3. Modiola alabamensis, 185. Modiola potomacensis, 185. Modiolus alabamensis, 59, 78, 79, 85, 87, 88, 185, 295. Modiolus marylandicus, 67, 71, 78, 79, 186, 295. Modiolus (Brachydontes) ensis, 185. Molluseoidea, 78, 79, 80, 81, 203. potomac- Mollusea, 74, 75, 76, 77, 78, 79, 122. Monodonta glandula, 157. Morio brevidentata, 63, 76, 77, 85, 86, 4, 276. Mucronella aspera, 63, 80, 81, 227, 312. Multicrescis parvicella, 259. Muricidea, 135. Myliobatis, 98. Myliobatis copeanus, 59, 74, 75, 99, 264, 265. Myliobatis holmesii, 100. Myliobatis magister, 100, 264, 265. Myliobatis pachyodon, 99. Myliobatis pentoni, 100. Myliobatis sp., 101, 265. Myliobatidae, 98. Mytilidae, 185. Narona, 129. Naticidae, 150. Natica cliftonensis, 76, 77, 150, 280. Natica eminula var., 151. Nautiloidea, 122. Nautilus (Orthoceras) costatus, 240. Nautilus legumen, 240. Nautilus lobatulus, 252. Nautilus obliquus, 239. Nautilus sp., 122. Niso umbilicata, 63, 76, 77, 85, 86, 156, 281. Nodosaria affinis, 66, 80, 81, 236, 314. Nodosaria bacillum, 59, 80, 81, 236, 314. Nodosaria communis, 60, 80, 81, 237, 314. Nodosaria econsorbrina v. emaciata, 63, 80, 81, 238, 314. Nodosaria obliqua, 63, 80, 81, 259, 314. Nodosaria sandbergeri, 63, 80, 81, 238, 314. Nodosaridae, 236. Noetia pulchra, 195. Nonionina affinis, 67, 80, 81, 257, 316. Nonionina punctata, 257. Nucula capsiopsis, 201. Nucula cultelliformis, 198. Nueula improcera, 199. Nucula magnifica, 202. Nucula ovula, 72, 78, 79, 85, 86, 202, 309. Nucula parilis, 199. Nueula parva, 197. Nueula potomacensis, 64, 67, 78, 79. 202, 309. 328 PALEONTOLOGICAL INDEX Nuculana cultelliformis, 198. Nuculana improcera, 199. Nuculana parva, 197. Nuculana protexta, 200, 201. Nuculidae, 202. O. Odontaspis, 103, 106. Odontaspis cuspidata, 59, 74, 75, 105, 266. Odontaspis elegans, 61, 74, 75, 104, 266. Odontaspis hopei, 105. Odontaspis macrota, 61, 74, 75, 104, 105, 266. Odostomia insignifiea, 156. Odostomia trapaquara, 63, 76, 77, 85, 86, 87, 156, 281. Olividae, 130. Olivula sp., 66, 74, 75, 130. Olivula staminea, 130. Onychocella, 216. Opisthobranchiata, 123. Orthochaenites, 122. Oryctomya, 183. Osteodes elaborata, 229. Ostrea bellovacina, 190. Ostrea compressirostra, 60, 61, 64, 66, GE), Kil, 725 Tey MS, WO, SH, HO; WO, Sal, 192, 297, 298. Ostrea compressirostra var. alepido- ta, 61, 62, 78, 79, 197. Ostrea (Gryphaeostrea) IG Ostrea (Gryphaeostrea) vomer, 59, 78, 79, 85, 87, 89, 198, 302. Ostrea sellaeformis, 64, - Rue Seen 83, 85, 88, 89, 191, 192, 300, 301. Ostrea sinuosa, 190. Ostrea sp., 193. Ostrea subeversa, 193. Ostracoda, 74, 75, 116. Ostreidae, 190. Otodus macrotus, 105. Otodus obliquus, 61, 74, Otolites, 113, 264. Oxyrhina, 106. subeversa, 75, 106, 267. ee Panopea elongata, 60, 69, 72, 73, 76, 77, 162, 282. Papillina staminea var., 137. Paracyathus alternatus, 227. Paracyathus (?) clarkeanus, 225. Paracyathus granulosus, 227. Paracyathus marylandicus, 63, 80, 81, ZAG, aile\- Parallelodontidae, 196. Pasithea umbilicata, 156. Pavolunulites elegans, 217. Pecten calvatus, 189. Pecten choctavensis, 59, 78, 79, 85, 87, 88, 188, 189, 296. Pecten coe 67, 70, 78, 79, 85, 87, 89, 188, 2 Pecten eGR frontalis, 188. Pecten greggi, 189. Pecten johnsoni, 78, 79, 85, 86, 88, 189, 190, 296. Pecten rogersi, 188. Pecten sp., 63, 78, 79, 190, 296. Pecten wahtubbeanus, 190. Pectinidae, 188. Pectuneculus decisus, 195.- Pectunculus idoneus, 194. Pelecypoda, 76, 77, 78, 79, 160. Periploma (?) sp., 65, 78, 79, 184. “‘Periplomidae, 184. Peronidia, 167. Phenacomya petrosa, 62, 282. Pholadomya Pe, G25 Oo smaios 79, 184, 29 Bao 184. Pholas petrosa, 161. Pholadidae, 161. Phyllodus, 172.. Phyllodus hipparionyx, 113. Phyllodus sp. aff. toliapicus, 113. Phyllodus toliapicus, 112. Phymatocoryon mackayi, 259. Pisces, 74, 75, 93, 98. Placosmilia (Trochosmilia) connivens, 229, 230: Plantae, 80, 81, 98, 258, 316. Platidia marylandica, 63, 72, 78, 79, 203, 310. Pleurophoridae, 183. 76, 77, 161, mee ine ehildreni, 63, 74, 75, 85, 86, 187, 272. Finusetone ducateli, 63, 74, ° 75, . 226, 979 wle. Pleurotoma dentieula, 127. Pleurotoma denticula var., 127. Pleurotoma harrisi, 63, 74, 75, 125, 126, 272. Pleurotoma (Hemipleurotoma) chil- dreni, 127. PALEONTOLOGICAL INDEX Mea eay) Pleurotoma nasuta, 126. Pleurotoma piscatavensis, 63, 74, 75, 127, 272. . Pleurotoma potomacensis, 63, 74, 75, 126; 22: Pleurotoma tysoni, 63, 74, 75, 126, 272. Pleurotomella bellistriata, 128. Pleurotomidae, 125. Polymorphina anceps, 247. Polymorphina austriaca, 66, 80, 81, 244, 315. Polymorphina communis, 80, 81, 244, 248, 315. Polymorphina complanata, 246. Polymorphina compressa, 80, 81, 246, 315. Polymorphina cylindroides, 246. Polymorphina elegantissima, 66, 80, 81, 247, 315. Polymorphina frondiformis, 246. Polymorphina gibba, 59, 80, 81, 248, 249, 315. Polymorphina lactea, 63, 80, 81, 248, Silos Polymorphina praelonga, 66, 80, 81, 249, 315. Polymorphina problema, 244, 245, 249. Polymorphina problema var. deltoi- dea, 247. Prionodesmacea, 185. Protocardia lenis, 59, 67, 70, 71, 73, 78, 79, 172, 288. Protoecardia virginiana, 172. Protosphyraena, 111. Protozoa, 80, 81, 233. Pseudoliva sp., 63, 76, 77, 140, 264. Pseudoliva venusta, 140. Pteria limula, 72, 78, 79, 85, 87, 88, 89, 194, 303. Pteriidae, 194. Ptenoglossa, 153. Pulvinulina exigua var. obtusa, 80, 81, 255, 316. Pulvinulina karsteni, 256. Pulvinulina schreibersii, 67, 80, 81, 256, 316. Pyramidellidae, 155. Pyrgiscus, 155. Pyropsis pyrula, 137, 138. Pyropsis (?) sp., 138. Pyrula cancellata, 141. Pyrula elegantissima, 141, 142. Pyrula juvenis, 143. Pyrula penita var., 66, 76, 77, 85, 88, 89, 141, 276. Pyrula (?) sp., 66, 76, 77, 142, 276. Pyrula tricarinata, 141. R. Rachiglossa, 130. Reptescharipora, 218. Reptilia, 74, 75, 95. Reptocelleporaria aspera, 220. Reptoflustrella heteropora, 80, 81, 213. 3il2. Reticulipora dichotoma, 63, 78, 79, 207, Ball. Rhipidoglossa, 157. Rhizopoda, 233. Ringicula dalli, 67, 70, 74, 124, 272. Ringiculidae, 124. Robulina concinna, 241. Robulina radiata, 243. Rosalina ammonoides, 254. Rosalina bertheloti, 251. Rotalia (Trochulina) turbo, 251. Rotalidae, 251. Rotalina schreibersii, 256. Rotalina ungeriana, 253. Ss. Saxicavidae, 162. Seala carinata, 63, 76, 77, 154, 280. Scala potomacensis, 63,76, 77, 154, 280. Seala sessilis, 63, 76, 77, 154, 280. Seala virginiana, 60, 76, 77, 153, 280. Sealariidae, 153. Scapanorhynehus, 103. Scaphandridae, 124. Seaphopoda, 76, 77, 158. Selachian vertebrae, 1/0. Semiescharipora, 218. Serpula lactea, 248. Simpulum showalteri, 141. Siphonodentaliidae, 159. Solariidae, 153. Solarium sp., 60, 76, 77, 153, 280. Solen lisbonensis (?), 65, 76, 77, 165, 285. Solen (Plectosolen) lisbonensis, 165. Solen (Plectosolen) lisbonensis var. abruptus, 165. Solen sp., 165. Solenidae, 165. Solenoconchia, 158. Solemya petricoloides, 186. Spatangidae, 232. 330 PALEONTOLOGICAL INDEX Spatangidea, 232. Sphyraena speciosa, 111. Sphyrna, 109. Sphyrna denticulata, 110. Sphyrna prisea, 61, 74, 75, 110, 266. Spiroplecta americana, 235. Spiroplecta biformis, 236. Spiroplecta clarki, 66, 80, 81, 235, 314. Squalus auriculatus, 108. Strepsidura subsealarina, 59, 70, 74, 75, 136, 274. Strombidae, 145. Synechodus, 102. Synechodus clarkii, 61, 74, 75, 103, 266. Syrnola trapaquara, 156. T. Taenioglossa, 141. Tectibranchiata, 123. Tectospondyli, 98. Teleodesmacea, 160. Teleostomi, 110, 264. Teleotremata, 203. Tellina greggi, 166. Tellina subtriangularis, 167. Tellina virginiana, 59, 76, 77, 166, 285. Tellina williamsi, 76, 77, 767, 285. Tellina (Angelus) virginiana, 166. Tellina (Peronidae) papyria (?), 76, Big Wow Tellina (Peronidia ?) williamsi, 167. Tellinidae, 166. — Terebratellidae, 203. Terebratula harlani, 61, 78, 79, 194, 204, 310. Terebratulidae, 204. Teredinidae, 160. Teredo virginiana, 76, 77, 160, 282. Testudenata, 97. Tetrabranchiata, 122. Textularia abbreviata, 233. Textularia hauerii, 233. Textularia gramen, 63, 80, 81, 233, 314. Textularia sagittula, 63, 80, 81, 254, 314. Textularia subangulata, 61, 80, 81, 234, 314. Textularidae, 233. Thecachampsa antiqua, 96. Thecachampsa contusor, 61, 74, 75, 96, 262. Theeachampsa marylandica, 60, 74, 75, 96, 262. Thecachampsa sericodon (?), 61, 74, 75, 95, 262. Thecachampsa sp., 60, 74, 75, 95, 262. Tornatella bella, 123. Tornatellaea bella, 59, 66, 70, 74, 75, 85, 86, 88, 123, 272. Toxoglossa, 125. Trigonoarea decisa var., 78, 79, 85, 88, 195, 303. ; Trigonoarcea pulchra, 195. Trigonoarca pulehra var., 195. Trionychia, 97. Trionychidae, 97. Trionyx virginiana, 61, 74, 75, 97, 263. Tritonidae, 141. Tritonium showalteri, 63, 76, 77, 141, 276. ; Trochidae, 157. Trochocyathus clarkeanus, 60, 62, 80, Sil, 2ei5 BB, Trochosmilia connivens, 229. Trochus apertus, 152. Trophon sublevis, 63, 74, 75, 85, 86,. 135, 274, -Trunecatulina boueana, 253. Truncatulina grosserugosa, 254. Truneatulina lobatula, 80, 81, 251, 252, 316. Truncatulina refulgens, 252. Trunecatulina ungeriana, 59, 80, 81, 253, 316. Truneatulina variabilis, 253. Truneatulina wuellerstorfi, 253. Tuba marylandica, 76, 77, 155, 281. Tubuliporidae, 205. Tudicla marylandica, 63, 76, 77, 137, 275. Tudicla sp., 61, 62, 76, 77, 138, 275. Tudicla (?) sp., 76, 77, 138, 275, 276. Turbinella pyruloides, 131. Turbinolia acuticostata, 43, 62, 80, 81, 223, 313. Turbinolia elaborata, 229. Turbinolia pharetra, 224, 225. Turbinolia pileolus, 231. Turbinolia wautubbeensis, 224. Turbinolidae, 222, 223. Turbonilla potomacensis, 63, 76, 77, 155, 281. Turritella humerosa, 60, 61, 64, 69, 71, TORS Ta MTs tii tO, WAS BOO Turritella mortoni, 60, 61, 62, 64, 68, 69, 72, 78, 76, 77, 85, 86, 147, 148, 149, 278. PALEONTOLOGICAL INDEX bol Turritella mortoni var. postmortoni, 147. Turritella obruta, 149. Turritella potomacensis, 67, 70, 71, 76, Tia 1D, BED Turritella venusta, 149. Turritellidae, 147. V. Vaginulina legumen, 61, 80, 81, 240, OO BAB Venericardia, 177. Venericardia ascia, 177. Venericardia marylandica, 67, 78, 79, 179, 292. Venericardia pectuncularis, 179. Venericardia planicosta, 177, 178. Venericardia planicosta var. regia, 60, "2, 73, 78, 79, 85, 178, 290, 291, 292. Venericardia potapacoensis, 64, 65, 66, OB); 705 Wale We, sh, WS, We), BOP. Venericardia regia, 178. Veneridae, 168. Vermetidae, 150. Vermetus sp., 60, 76, 77, 150, 279. Vertebrata, 95. Voluta petrosa, 130. Volutidae, 130. ‘ Volutilithes (Athleta) tuomeyi, 130. Volutilithes petrosus, 59, 74, 75, 85, 86, 88, 130, 273. Volutilithes sp., 60, 74, 75, 131, 273. xX. Xiphias, 1/1. Xiphias (?) radiata, 61, 74, 75, 112, 264. Ye Yoldia cultelliformis, 198. PAGE > 61 line 10 for G3 eid a cc 68 « 43° gore saul, ign sae 820 ES Plate XX ; ee costata read Re costata Wanginale costata read. aang costata ‘ERRATA, oP te SOnbiis obliquus read Otodus obliquus.. ih eos se me Reticulipora | dichomata read Reticulipora dichotoma. sie a3 co ee 155 ce Gt therefore read their Fest var Cephalopoda read Gastropoda, DATE DUE arvard MCZ Library ‘Wiig 408 372 — = eee = = a oo