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

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

• Paleocoordinates: 10.8° N, 58.5° W (Wright 2013)

• 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: CC0 (CC0)

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.
Gastropoda
 Heterostropha - Architectonicidae
Bivalvia
 Nuculanida - Nuculanidae
"Adrana perprotracta" = Adrana newcombi
"Adrana perprotracta" = Adrana newcombi Angas 1878 pointed nut clam
 Pectinida - Pectinoidae
"Aequipecten (Plagioctenium) demiurgus" = Argopecten demiurgus, Pecten (Pecten) archon
"Aequipecten (Plagioctenium) demiurgus" = Argopecten demiurgus Dall 1898 calico scallop
 Pectinida - Anomiidae
Anomia simplex d'Orbigny 1845 jingle
 Arcida - Arcidae
"Anadara (Scapharca) placata" = Scapharca, Anadara (Anadara) inaequilateralis
"Anadara (Scapharca) placata" = Scapharca clam
 Pholadida - Corbulidae
"Notocorbula islatrinitatis" = Varicorbula islatrinitatis Maury 1925 clam
 Cardiida - Cardiidae
"Trigoniocardia (Trigoniocardia) melajoensis" = Trigoniocardia (Goniacardia) melajoensis Jung 1969 cockle
 Cardiida - Tellinidae
Macoma (Psammacoma) "sp. A", "Apolymetis trinitaria" = Florimetis trinitaria, "Eurytellina melajoensis" = Tellina (Eurytellina)
Macoma (Psammacoma) "sp. A" Dall 1900 tellin clam
"Apolymetis trinitaria" = Florimetis trinitaria Dall 1900 tellin clam
"Eurytellina melajoensis" = Tellina (Eurytellina) tellin clam
 Cardiida - Solecurtidae
 Cardiida - Veneridae
Macrocallista maculata, Pleiorytis caroniana, "Chione (Lirophora) caroniana" = Lirophora, "Dosinia (Dosinia) grandis" = Dosinia ponderosa
Macrocallista maculata Linnaeus 1758 venus clam
Pleiorytis caroniana Maury 1925 venus clam
"Chione (Lirophora) caroniana" = Lirophora venus clam
"Dosinia (Dosinia) grandis" = Dosinia ponderosa Gray 1838 ponderous dosinia
 Carditida - Crassatellidae
"Eucrassatella trinitaria" = Eucrassatella (Hybolophus) trinitaria
"Eucrassatella trinitaria" = Eucrassatella (Hybolophus) trinitaria Maury 1925 clam
Gastropoda
 Vanikoroidea - Eulimidae
 Neotaenioglossa - Calyptraeidae
Crepidula plana Say 1822 slipper shell
 Sorbeoconcha - 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
 Sorbeoconcha - Vermetidae
Petaloconchus sculpturatus alcimus Mansfield 1925 worm shell
 Neogastropoda - Terebridae
 Neogastropoda - Conidae
Conus couvaensis Vokes 1938 cone shell
"Conus springvalensis" = Conus imitator springvalensis Mansfield 1925 cone shell
 Neogastropoda - Cancellariidae
Cancellaria cf. sanctifrancisci, "Trigonostoma (Emmonsella) sp." = Ventrilia, "Cancellaria (Charcolleria) sp." = Massyla, "Cancellaria (Euclia) montserratensis" = Euclia montserratensis
"Trigonostoma (Emmonsella) sp." = Ventrilia Jousseaume 1887 snail
"Cancellaria (Charcolleria) sp." = Massyla Adams and Adams 1854 snail
"Cancellaria (Euclia) montserratensis" = Euclia montserratensis Maury 1925 snail
 Neogastropoda - Marginellidae
Prunum (Egouena) springvalensis Maury 1925 margin shell
Prunum (Egouena) calypsonis Maury 1925 margin shell
Volvarina "sp. A" Hinds 1844 margin shell
 Neogastropoda - Muricidae
Chicoreus (Triplex) cornurectus, "Murex (Murex) chrysostoma" = Vokesimurex chrysostoma, "Murex (Phyllonotus) cf. pomum" = Chicoreus (Phyllonotus) pomum, "Thais (Stramonita) "sp. A"" = Stramonita
Chicoreus (Triplex) cornurectus Guppy 1876 murex snail
"Murex (Murex) chrysostoma" = Vokesimurex chrysostoma Sowerby 1834 murex snail
"Murex (Phyllonotus) cf. pomum" = Chicoreus (Phyllonotus) pomum Gmelin 1791 murex snail
"Thais (Stramonita) "sp. A"" = Stramonita Schumacher 1817 murex snail
 Neogastropoda - Cystiscidae
"Persicula (Rabicea) couviana" = Persicula propeobesa
"Persicula (Rabicea) couviana" = Persicula propeobesa Mansfield 1925 snail
 Neogastropoda - Columbellidae
"Strombina melajoensis" = Sincola (Dorsina) melajoensis Jung 1969 dove shell
 Neogastropoda - Fasciolariidae
Fusinus sp. Rafinesque 1815 spindle shell
 Neogastropoda - Nassariidae
Nassarius (Uzita) "sp. A" Adams and Adams 1853 snail
Gordanops baranoanus Anderson 1929 snail
 Neogastropoda - Buccinidae
Cantharus sp. Röding 1798 true whelk
 Neogastropoda - Olividae
Oliva (Oliva) couvana Maury 1925 olive snail
 Neogastropoda - Ancillariidae
"Ancilla (Eburna) caroniana" = Eburna caroniana
"Ancilla (Eburna) caroniana" = Eburna caroniana Maury 1925 snail
 Sorbeoconcha - Ranellidae
Cymatium sp. Röding 1798 triton shell
 Sorbeoconcha - Bursidae
"Bursa (Bursa) aff. thomae" = Bursa rhodostoma
"Bursa (Bursa) aff. thomae" = Bursa rhodostoma Sowerby 1835 frog shell
 Cerithioidea - Turritellidae
 Trochoidea - Trochidae
"Calliostoma caronianum" = Calliostoma (Calliostoma) caronianum
"Calliostoma caronianum" = Calliostoma (Calliostoma) caronianum Maury 1925 top snail
Scaphopoda
 Dentaliida - Dentaliidae