A PLIOCENE MOLLUSCAN FAUNULE FROM TRINIDAD PETER JUNG NATUHI-IISTORISCHES MUSEUM, BASEL, SWITZERLAND

INTRODUCTION Aequipecten ( Plagioctenium) spectes A report on Miocene and Pliocene mol­ Anon~ia simplex d'Orbigny lusks from Trinidad ( Jung, 1969) was Crassmella species completed when the writer undertook the Trachycardium (Dallocardia) scmctidavi­ identification of a small molluscan fauna dis (Maury) fron1 the Talparo Formation of Trinidad. Semele purpu1ras cens ( Gmelin) This faunule had been collected by Karl Strigilla ( Pisostrigilla) pisijo1rmis Rohr ( KR 13900 ) in the Mahaica (Linne) District, which is situated on the north­ Donax d. D. striatozts Linne ern slope of the Central R ange of Trinidad, ]uliacorbula aequivalvis (Philippi) about 14 kilometers south of Arima. The Gastropoda: fossiliferous outcrop had been found in Diodo1ra cayenensis (Lamarck) a branch stream of the Cunupia River N eritina species (coordinates: N 360' 060 links, E 445' Turritella (Broderiptella) aff. T. plani- 260 links ) . The exact geographic location gyrata Guppy of this outcrop is shown on a detailed C erithiopsis species map to be published by H . G. Kugler, Basel. Modulus species According to Kugler ( 1961, map) this lo­ Triphora species cality ( = Naturhistorisches Museum Basel Natica (Naticarius) aff. N. canrena locality 1043 7), which is situated on the (Linne) axis of the Mahaica anticline, belongs to the Crucibul-ztm ( C1rucibulum) piliferum Caparo Clay Member of the Talparo Forma­ Guppy tion and has been selected as the type lo­ Olivella (Niteoliva) d. 0. verreauxii cality for n1ollusks of the Caparo Clay Mem­ (Ducros) ber (Kugler MS ) . Prunttm ( Prmzum) aff. P. dallianum According to Rohr (private report, 193 7) (Maury) the faunule came from a 15 feet thick lens of limonitic or glauconitic conglomeratic Of these 22 forms there are 12 species sandstone situated in the uppermost part occurring in the Manua shell bed as well. of the Caparo Clay Member. The lithologi­ The remaining 10 forms belong to genera cal and faunistical aspects of the faunule represented also at Manua. But unfortu­ are strikingly similar to those of the fauna nately they are not determinable specifically, from the Matura shell bed. Their correla­ although it is probable that they are con­ tion, therefore, seems highly probable. specific with those found at Manua. Ba1'­ batia ( Obliquarca) d. B. cancellcwia (La­ FAUNA marck) and Prunum ( Pr-zmum) aff. P. All the specimens contained in this dallianttm (Maury) are the only species not faunule are strongly rolled, a feature ob­ recorded from Manua. In addition the form served frequently in material from the listed above as Modulus species is repre­ Matura shell bed as well. A number of sented by a single, fragmentary, worn speci­ forms cannot be identified specifically, be­ men, and is not conspecific with M. car­ cause they are represented by small frag­ chedonitts (Lamarck) recorded from the ments only. The following 22 forms have Manua shell bed (Jung, 1969, p. 452). been recognized from NHMB locality 104 3 7 : Genus BARBATIA Gray Pelecypod a: Gray, 1842, Synopsis of the contents of the British Museum, eel. 44, p. 81. Barbatia ( 0 bliquctfCa) d. B. cancellaria (Lamarck) Type species (by subsequent designation, N oetia ( Eontia) cent1ro ta (Guppy) Gray, 1847, Proc. Zool. Soc. London, pt. Brachydontes species 15, p. 197), Area barbata Linne. Recent, 0 strea species Mediterranean Sea. 85 86 T11lane St11dies Ill Geolog)' and Paleontology Vol. 7

Subgenus OBLIQUARCA Sacco Genus NOETIA Gray Sacco, 1~9~, I .Molluschi dci terreni terziarii Gray, 1857, Ann. Mag. Nat. Hist., ( ser. 2) vol. del Piemonte e della Liguria, pt. 26, p. 16. 19, p. 371. Type species (by original designation), Type species ( by monotypy), N oetict tri­ Area modiolifonnis Deshayes. Eocene, aJzgularis Gray ( = Area 11everset G. B. Paris Basin. Sower by I ) . Recent, eastern Pacific. BARBATIA (0BLIQUARCA) d. Subgenus EONTIA MacNeil B. CANCELLARIA (Lamarck) \facNeil, 1938, U. S. Geol. Survey, Prof. Paper Plate 1, figs. 1,2 189-A, p. 11. This species is represented by a few in­ Type species ( by original designation) , Aua complete and strongly worn shells. The lack ponderosa Say. Recent, east coast of the of reduced denticles at the center of the United States. hinge may be due to erosion. The ligament NOETIA (EONTIA) CENTROTA (Guppy) is narrow and restricted to the area behind the beaks. The external sculpture is hardly Plate 1, figs. 3,4 recognizable, but consists of numerous ra­ 1867 Area centrota Guppy, Proc. Sci. Assoc. dials. Trinidad, pt. 3, p. 175. (Reprint, Harris, 1921, Bulls. Amer. P:;]eontology, vol. 8, no. 35, p. 54.) B. cancellaria sometimes occurs abundantly 1938 Eontia cent rota (Guppy), MacNeil, U. S. in the Recent Caribbean fauna (Abbott, Ceol. Survey, Prof. Paper 189-A, p. 12, pJ. 1. 1958, p. 110). It is usually assigned to the figs. 11,12. Lectotype figured. For adcbtional subgenus Barbatia. Sacco originally included citations see this publication. 1942 Eontia centrota (Cuppy), Rutscb, Verh. only modioliform species in his subgenus Naturf. Ges. Basel, vol. 54, p. 110. Obliquctrca, but Woodring ( 1925, pp. 38- Lectotupe: USNM 496508. 40) described three species from the Bow­ Tupe lo calitu: Matura, 'Trinidad. den Formation of Jamaica, two of which Although most abundant at its type lo­ are not modioliform at all. According to cality, this species is represented only by a Reinhart (1935, p. 25) Obliqztarca is dis­ few valves in the faunule under study. They tinguished from Barbatia s. str. by having do not reach the size of valves from the its ligament entirely behind the umbones. Matura shell bed. As stated by Olsson ( 1961, p. 81) "the N. cent11ota has not been found outside ligament covers only the posterior part of Trinidad yet. It has been collected from de­ the cardinal area" in B. cancellaria. posits of late Miocene to Pliocene age.

EXPLANATION OF PLATE 1 Figure Page All the specimens are from Naturhistorisches Museum Basel locality 1043 7. 1,2 Barbatia ( Obliqttm'ca) d. B. cancellaria (Lamarck) (X 2) ______86 Length 22.3 mm; height 12 .8 mm. Nat. hist. Mus. Basel No. G 14061. 3,4 N oetia ( Eontia) centrota (Guppy) (X 2) ______86 Length 22.2 mm; height 14.3 mm. Nat. hist. Mus. Basel No. G 14062. 5 ]ztliacorbula aeqztivctlvis (Philippi) (X 5) __ __ 88 Length 6.7 mm; height 5.1 n1m. Nat. hist. Mus. Basel No. G 14063. 6 C11ucibztlttm ( Crucibztlum) pilifentm Guppy (X 2) ______88 Maximum diameter 16.7 mm. Nat. hist. Mus. Basel No. H. 15402. 7 Tunitella ( B1roderiptellct) aff. T. planig)wata G uppy (X 2) _ 88 Height 32.0 mm; maximum diameter 14.2 mm. Nat. hist. Mus. Basel No. H . 15401. 8 Pnmum ( P11unum) aff. P. dallianzmz (Maury) (X 2) _ _ _ 88 Height 21.2 mm; width 17.2 mm. Nat. hist. Mus. Basel No. H. 15403. No. 2 Pliocene Molluscan Faunule) Trinidad 87

2

5 6

PLATE 1 T ulane Studies in Geolog;· and Paleontology Vol. 7

Genus JULIACORBULA Olsson and Harbison Genus CRUCIBULUM Schumacher Olsson and Harhison, 195.3, Acad. Nat. Sci. Schumacher, 1817, Essai d'un nouveau systeme Philadelphia, .\tonograph no. 8, p. 148. des habitations des vers testaccs, pp. 56,182. Type species ( by subsequent designation, Type species (by original designation), Burch, 1946, Min. Conchological Club Corbula cubaniana d'Orbigny ( = Cor­ Southern California, No. 56, p. 19), bttla knoxiana C. B. Adams = Corbttla Crucibztlum planum Schumacher ( = Pa­ aequi-vafvis Philippi ). Recent, Florida tella auricula Gmelin) . Recent, Florida and Caribbean. and West Indies.

JULIACORBULA AEQU IVALVIS ( Philippi) Subgenus CR UC IBULUM s. str. Plate 1, fig. 5 CRUCIBULUM ( CRUC IB ULUM) 18.36 Corlmla aect uivalv is Philippi, Archiv hir PILIFERUM Guppy P.'aturg., 'ol. 2, p. 227, pl. 7, fig. 4. Plate 1, fig. 6 1964 Corbula ( ]uliacorbula) aequivalvis Phi­ lippi, \Veishord, Bulls. Amer. Paleontology, 1867 C ru cib ulum piliferum Guppy, Proc. Sci. vol. 45, no. 204, p . .39.3, pl. 57, figs . .3- 6. For Assoc. Trinidad, pt. 3, pp. 160,172. ( Reprint, further citation see this publication. Harris, 1921 , Bulls. Amer. Paleontology, vol. 8, no. 35, pp. 39,51. ) ]. aequivalt1is occurs abundantly in the This species is represented by five speci­ Matura shell bed, but is represented in the mens. Their spines are but poorly developed, faunule under study by a few valves only. or even absent on account of erosion. Un­ At Matura the specimens vary in shape from usually fl at shells such as occur at Matura subquadrate to elongate. The same variability are m1ss mg. is shown by the Mahaica valves. R elated forms are discussed elsewhere ( Jung, 1969, Genus PRUNUM Herrmannsen p. 410). Herrmannsen, 1852, Indicis generum malaco­ zoorum. Supplementa et corrigenda, p. 113. Genus T URRITELLA Lamarck Type species ( by monotypy ) , V oluta prunum Lamarck 1799, Mcm. Soc. Hist. Nat. Paris, p. Gmelin. Recent, West Indies. 74. Subgenus PRUNUM s. str. Type species ( by monotypy), Turbo terebra PRUNUM ( PRUNUM) aff. Linne. Recent, western Pacific. P. DALLIANUM (Maury ) Subgenus BRODERIPTELLA Olsson Plate 1, fig. 8 Olsson, 1964, Neogene mollusks from north­ A single shell is available. It is damaged western Ecuador, p. 188. Paleont. Research and somewhat worn, but its outer lip is Inst., Ithaca, N. Y. preserved. P. dallianum (Maury) ( 1912, Type species ( by original designation) , T ur­ p. 67, pl. 10, figs. 5, 6 ) was originally de­ ritella broderipiana d'Orbigny. Recent, scribed from the Courbaril beds (Pliocene) eastern Pacific. of the Pitch Lake area, Trinidad. Comparison with topotypes shows that the Mahaica TURRITELLA ( BRODERIPTELLA) aff. speci­ men is stouter. The upper part of its body T. PLANIGYRATA Guppy whorl is more inflated, the lower part n1ore Plate 1, fig. 7 constricted, and its outer lip is more strongly arched. The columellar folds are heavier than This species is fairly frequent at Mattua in P. dallianum. and its affinities to T . planigyrata Guppy A few specimens from Mattua have ques­ 1867, pp. 156,1 69) and to the Recent Carib­ tionably been identified as P. dallianum bean T. 'ZJarie gat a ( Linne) have been de­ ( Jung, 1969, p. 533). They are more slender scribed by the writer (Jung, 1969, p. 43 9 ). than the Mahaica shell. The Mahaica faunule contains only four frag­ mentary specimens. They are indistinguish­ CONCLUSIONS able from Matura specimens. The figured The Talparo Formation consists of a shell is somewhat compressed laterally. rather heterogeneous sequence of deposits. No.2 Pliocene Molluscan Faunule Trinidad 1 89

Its most promi~ent features are the large within the the Caparo Clay Member of the bodies of practically unconsolidated sands Talparo Formation on account of the strik­ in predominantly clayey sediments. Occa­ ing faunistic and lithological similarity with sional lenses yielding a fauna like the one the fauna recorded herein. discussed in this paper represent a marine near-shore environment with slight brackish LITERATURE CITED water influence. The presence of Cyano­ ABBOTT, R. T., 1958, The marine mollusks of cyclcts or Anadara ( Larkinia ) patricia point Grand Cayman Island, British West Indies: Acad. Nat. Sci. Philadelphia, Monograph no. to strong brackish water influence. Lignitic 11, p. 1-1.38, pls. 1-5, 10 maps, 7 text-figs. beds associated with sands containing pos­ CuPPY, R. J. L., 1867, On the Tertiary fossils sible traces of decayed mangrove roots sug­ of the West Indies with especial reference to gest a coast swamp environment, whereas the classification of the Kainozoic rocks of Trinidad: Sci. Assoc. Trinidad, Proc., pt. 3, fossils like Hyria and H ernisinus prove the p. 145-176. (Reprinted by Harris, G. D., presence of fresh water. 1921, Bull. Amer. Paleontology, vol. 8, no . The Talparo Formation represents part 35, p. 24-55.) of the sediments filling the basin situated JuNe, PETEH, 1969, Miocene and Pliocene mol­ lusks from Trinidad: Bull. Amer. Paleontol­ between the present Central and Northern ogy, vo l. 55, no. 247, p. 289-657, pls. 1.3-60, Ranges ( Caroni Syncline ) . The composition text figs. 1-4. of the sediments as outlined above points KucLEH, H. G., 1953, Jurassic to Recent sedi­ to an unsteady environment with fluctua­ mentary environments in Trinidad: Assoc. Suisse Geol. Ing. Petrole, Bull., vol. 20, no. tions of the sea. Kugler ( 1961, map ) sub­ 59, p. 27-60, 2 text-figs. divided the Talparo Formation into seven KucLEH, H. C ., 1961, Geological map of Trini­ members. The mollusc~n fauna recorded dad, 1: 100,000, compiled 1959: Orell Fiissli, Ziirich, Switzerland. herein has been collected from a lens in MAUHY, C. J., 1912, A contribution to the pale­ the Caparo Clay Member, in the middle ontology of Trinidad: Acad. 1\at. Sci. Phil­ member of the formation. The Manua beds adelphia, Jour., ( ser. 2). vol. 15, p. 25-112, pls. 5-13. are considered by Kugler ( 1961, map ) to OLSSON, A. A., 1961, Molluscs of the tropical be the top member of the Talparo Forma­ eastern Pacific. Particularly from the south­ tion and the last marine transgression (Kug­ ern half of the Panamic-Pacific faunal prov­ ince (Panama to Peru). Panamic-Pacific ler, 195 3, p.5 5). Pelecypoda: Paleont. Research Inst., Ithaca, According to field observations the ma­ N.Y., p. 1-574, pls. 1-86. rine lens of the Mahaica District represents REIXHAHT, P. W., 1935, Classification of the pelecypod family Arcidae: Mus. Roy. Hist. a lens within the Caparo Clay Member, Nat. Belgique, Bull., vol. 11, no. 13, p. 1-68, whereas the Man.ua beds can hardly be de­ pls. 1-5. fined as a member due to lack of strati­ Woom~ING, W. P., 1925, Miocene molluscs from Bowden, Jamaica. Pelecypods and scapha­ graphic relations. It is suggested that the pods: Carnegie Inst. \Vashington, Publ. no. Manua beds be considered as a marine lens 366, p. 1-222, pls. 1-28.

July 16, 1969

RECENT BOOK

CYCLIC SEDIMENTATION, by P. Mel. sedimentation from continental, transitional D. Duff, A. Hallam and E. K. Walton. and marine environments, followed by chap­ Published by Elsevier Publishing Com­ ters on flysch and turbidity currents and on pany, Amsterdam, London and New York, faunal changes within sedimentary cycles. In the general conclusions, the authors state 1967, X + 280 pp., $23.50 that cyclicity is inherent in sedimentation Cyclic Sedimentation! the tenth volume in and that it is unrealistic to look for a the Developnzents in Sedimentology series, single all-embracing mechanism. They con­ is the first attempt at comprehensive treat­ clude with discussion of sedimentary, tec­ ment of this subject. Seven central chapters tonic, eustatic and climatic controls on cyclic describe and evaluate the evidence of cyclic development.