USGS 18634 - Melajo Clay, Melago River area (Miocene of Trinidad and Tobago)

Where: Trinidad and Tobago (10.6° N, 61.1° W: paleocoordinates 10.5° N, 59.6° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Melajo Clay Member (Springvale Formation), Late/Upper Miocene (11.6 - 5.3 Ma)

• The Melajo Clay Member of the Springvale Formation is correlated with the Savaneta Glaconitic Sandstone Member of the Springvale Formation, although part of it may be younger. The Melajo fauna is late Miocene in age. The Melajo Clay rests transgressively on the phyllites of the Northern Range with a basal conglomerate of about 1 m thickness. The conglomerate graes into a 1.5 m thick limestone, which is overlain by a bed of sand of about 1 m thickness. Above the sand is the Melajo Clay. The total thickness of the Melajo Clay is about 200 ft. It is unconformably overlain by Pleistocene sand and gravel deposits. Collection is derived from the basal limestone

• bed-level stratigraphic resolution

Environment/lithology: shallow subtidal; poorly lithified, shelly/skeletal, conglomeratic limestone

• The Melajo fauna can be divided into two assemblages: one occurring the limestone and coarse sand near the base of the Melajo Clay, the other on in the overlying clay and silty clay. The difference of the two assemblages is facies controlled. The basal assemblage represents a typical, tropical, near-shore fauna, whereas the overlying assemblage points to a deeper environment. This collection is derived from the basal assemblage, a carbonate and shallow water environment and is hence assigned to a carbontae - shallow subtidal environment.
• Limestone with large mollusks, that graded out of a conglomerate.

Size class: macrofossils

Reposited in the PRI, USNM

Collection methods: quarrying,

• All material descibed in this report is reposited in the Naturhistorisches Mueum, Basel, or the USNM. Additional material collection from this unit is found at PRI.

Primary reference: P. Jung. 1969. Miocene and Pliocene mollusks from Trinidad. Bulletins of American Paleontology 55(247):293-697 [A. Miller/A. Hendy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 60637: authorized by Austin Hendy, entered by Austin Hendy on 19.05.2006

Creative Commons license: CC BY (attribution)

Taxonomic list

• Exhaustive for Mollusca, although author suggests that further collection would reveal additional forms. Corals, bryozoa and spines of echinoderms also exists in the unit, though are not listed. Van de Bold (1963) also lists ostracords from several localities. Foraminiferal assemblages are also listed in unpublished reports by Saunders.
Bivalvia
 Arcida - Arcidae
"Anadara (Scapharca) placata" = Scapharca, Anadara (Anadara) inaequilateralis
"Anadara (Scapharca) placata" = Scapharca clam
 Pectinida - Pectinoidae
Pecten (Pecten) archon, "Aequipecten (Plagioctenium) demiurgus" = Argopecten demiurgus
"Aequipecten (Plagioctenium) demiurgus" = Argopecten demiurgus Dall 1898 calico scallop
 Pectinida - Anomiidae
Anomia simplex d'Orbigny 1845 jingle
 Carditida - Crassatellidae
"Eucrassatella trinitaria" = Eucrassatella (Hybolophus) trinitaria
"Eucrassatella trinitaria" = Eucrassatella (Hybolophus) trinitaria Maury 1925 clam
 Pholadida - Corbulidae
"Notocorbula islatrinitatis" = Varicorbula islatrinitatis Maury 1925 clam
 Cardiida - Veneridae
"Chione (Lirophora) caroniana" = Lirophora, "Dosinia (Dosinia) grandis" = Dosinia (Dosinia) ponderosa, Macrocallista maculata, Pleiorytis caroniana
"Chione (Lirophora) caroniana" = Lirophora venus clam
"Dosinia (Dosinia) grandis" = Dosinia (Dosinia) ponderosa Gray 1838 venus clam
Macrocallista maculata Linnaeus 1758 venus clam
Pleiorytis caroniana Maury 1925 venus clam
 Cardiida - Solecurtidae
 Cardiida - Tellinidae
"Apolymetis trinitaria" = Florimetis trinitaria, "Macoma (Psammacoma) "sp. A"" = Psammacoma, Eurytellina melajoensis
"Apolymetis trinitaria" = Florimetis trinitaria Dall 1900 tellin clam
"Macoma (Psammacoma) "sp. A"" = Psammacoma Dall 1900 tellin clam
 Cardiida - Cardiidae
"Trigoniocardia (Trigoniocardia) melajoensis" = Trigoniocardia (Goniacardia) melajoensis Jung 1969 cockle
 Protobranchia - Nuculanidae
"Adrana perprotracta" = Adrana newcombi
"Adrana perprotracta" = Adrana newcombi Angas 1878 pointed nut clam
Gastropoda
 Neogastropoda - Olividae
Oliva (Oliva) couvana Maury 1925 olive snail
 Neogastropoda -
"Ancilla (Eburna) caroniana" = Eburna caroniana
"Ancilla (Eburna) caroniana" = Eburna caroniana Maury 1925 snail
 Neogastropoda - Columbellidae
"Strombina ? melajoensis" = Sincola (Dorsina) melajoensis Jung 1969 snail
 Neogastropoda - Buccinidae
Cantharus ? sp. Röding 1798 true whelk
 Neogastropoda - Nassariidae
Gordanops baranoanus Anderson 1929 snail
Nassarius (Uzita) "sp. A" Adams and Adams 1853 snail
 Neogastropoda - Fasciolariidae
Fusinus sp. Rafinesque 1815 snail
 Neogastropoda - Cancellariidae
"Cancellaria (Euclia) montserratensis" = Euclia montserratensis, Cancellaria cf. sanctifrancisci, "Trigonostoma (Emmonsella) sp." = Ventrilia, "Cancellaria (Charcolleria) sp." = Massyla
"Cancellaria (Euclia) montserratensis" = Euclia montserratensis Maury 1925 snail
"Trigonostoma (Emmonsella) sp." = Ventrilia Jousseaume 1887 snail
"Cancellaria (Charcolleria) sp." = Massyla Adams and Adams 1854 snail
 Neogastropoda - Cystiscidae
"Persicula (Rabicea) couviana" = Persicula propeobesa
"Persicula (Rabicea) couviana" = Persicula propeobesa Mansfield 1925 snail
 Neogastropoda - Marginellidae
Prunum (Egouena) calypsonis Maury 1925 margin shell
Prunum (Egouena) springvalensis Maury 1925 margin shell
Volvarina "sp. A" Hinds 1844 margin shell
 Neogastropoda - Muricidae
Chicoreus (Triplex) cornurectus, "Murex (Phyllonotus) cf. pomum" = Chicoreus (Phyllonotus) pomum, "Murex (Murex) chrysostoma" = Vokesimurex chrysostoma, "Thais (Stramonita) "sp. A"" = Stramonita
Chicoreus (Triplex) cornurectus Guppy 1876 murex snail
"Murex (Phyllonotus) cf. pomum" = Chicoreus (Phyllonotus) pomum Gmelin 1791 murex snail
"Murex (Murex) chrysostoma" = Vokesimurex chrysostoma Sowerby 1834 murex snail
"Thais (Stramonita) "sp. A"" = Stramonita Schumacher 1817 murex snail
 Neogastropoda - Conidae
"Conus springvalensis" = Conus imitator springvalensis Mansfield 1925 cone shell
Conus couvaensis Vokes 1938 cone shell
 Neogastropoda - Terebridae
 Vanikoroidea - Eulimidae
 Naticoidea - Naticidae
"Natica (Naticarius) canrena" = Naticarius canrena, "Natica (Naticarius) aff. canrena" = Naticarius canrena, Polinices stanislasmeunieri
"Natica (Naticarius) canrena" = Naticarius canrena Linnaeus 1758 moon snail
"Natica (Naticarius) aff. canrena" = Naticarius canrena Linnaeus 1758 moon snail
Polinices stanislasmeunieri Maury 1917 moon snail
 Vermetoidea - Vermetidae
Petaloconchus sculpturatus Lea 1846 worm shell
Subspecies: P. sculpturatus alcimus
 Calyptraeoidea - Calyptraeidae
Crepidula plana Say 1822 slipper shell
 Tonnoidea - Ranellidae
Cymatium sp. Röding 1798 triton shell
 Tonnoidea - Bursidae
"Bursa (Bursa) aff. thomae" = Bursa rhodostoma
"Bursa (Bursa) aff. thomae" = Bursa rhodostoma Sowerby 1835 frog shell
 Sorbeoconcha - Turritellidae
 Architectonicoidea - Architectonicidae
"Architectonica (Architectonica) nobilis" = Architectonica nobilis
"Architectonica (Architectonica) nobilis" = Architectonica nobilis Röding 1798 sundial
Subspecies: A. (A.) nobilis nobilis
 Trochoidea - Trochidae
"Calliostoma caronianum" = Calliostoma (Calliostoma) caronianum
"Calliostoma caronianum" = Calliostoma (Calliostoma) caronianum Maury 1925 top snail
Scaphopoda
 Dentaliida - Dentaliidae