USGS 18411 - Melajo Clay, Melago River area: Late/Upper Miocene, Trinidad and Tobago

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Bivalvia - Arcida - Arcidae
Barbatia sp. Gray 1842
Bivalvia - Pectinida - Pectinidae
Pecten (Pecten) archon
Aequipecten (Plagioctenium) demiurgus Dall 1898
recombined as Argopecten demiurgus
Bivalvia - Carditida - Crassatellidae
Eucrassatella trinitaria (Maury 1925)
recombined as Eucrassatella (Hybolophus) trinitaria
Bivalvia - Pholadida - Corbulidae
Caryocorbula (Caryocorbula) helenae
Notocorbula islatrinitatis (Maury 1925)
recombined as Varicorbula islatrinitatis
Bivalvia - Cardiida - Veneridae
Chione (Lirophora) caroniana
original and current combination Lirophora
Macrocallista maculata (Linnaeus 1758)
Bivalvia - Cardiida - Solecurtidae
Tagelus (Mesopleura) mansfieldi
Bivalvia - Cardiida - Tellinidae
Apolymetis trinitaria (Dall 1900)
recombined as Florimetis trinitaria
Macoma (Psammacoma) informal sp. A (Dall 1900)
original and current combination Psammacoma
Bivalvia - Cardiida - Semelidae
Semele claytoni Maury 1917
Subspecies: Semele claytoni couvensis
Semele aff. anteriocosta Vokes 1938
Bivalvia - Cardiida - Cardiidae
Trachycardium (Dallocardia) sanctidavidis
original and current combination Dallocardia
Trigoniocardia (Trigoniocardia) melajoensis Jung 1969
recombined as Trigoniocardia (Goniacardia) melajoensis
Gastropoda - Neogastropoda - Olividae
Jaspidella sanctidominici (Maury 1917)
Oliva (Oliva) couvana Maury 1925
Gastropoda - Neogastropoda
Ancilla (Euburna) caroniana Maury 1925
recombined as Eburna caroniana
Gastropoda - Neogastropoda - Buccinidae
Colubraria sp. Schumacher 1817
Hanetia semiglobosa
Gastropoda - Neogastropoda - Nassariidae
Pallacera informal sp. A Woodring 1964
Nassarius (Uzita) informal sp. A (Adams and Adams 1853)
Gastropoda - Neogastropoda - Fasciolariidae
Fusinus sp. Rafinesque 1815
Gastropoda - Neogastropoda - Cancellariidae
Cancellaria cf. sanctifrancisci
Gastropoda - Neogastropoda - Cystiscidae
Persicula (Rabicea) couviana (Maury 1925)
synonym of Persicula propeobesa
Gastropoda - Neogastropoda - Marginellidae
Prunum (Egouena) calypsonis (Maury 1925)
Prunum (Egouena) springvalensis (Maury 1925)
Volvarina informal sp. A (Hinds 1844)
Gastropoda - Neogastropoda - Costellariidae
Conomitra sp. Conrad 1865
Gastropoda - Neogastropoda - Muricidae
Murex (Murex) chrysostoma Sowerby 1834
recombined as Vokesimurex chrysostoma
Thais (Stramonita) informal sp. A (Schumacher 1817)
original and current combination Stramonita
Gastropoda - Neogastropoda - Conidae
Conus springvalensis Mansfield 1925
recombined as Conus imitator springvalensis
Conus couvaensis Vokes 1938
Gastropoda - Eulimidae
Balcis egregia
Gastropoda - Naticidae
Natica (Naticarius) canrena (Linnaeus 1758)
recombined as Naticarius canrena
Gastropoda - Vermetidae
Petaloconchus sculpturatus Lea 1846
Subspecies: P. sculpturatus alcimus
Gastropoda - Calyptraeidae
Calyptraea centralis (Conrad 1841)
Gastropoda - Sorbeoconcha - Turritellidae
Turritella (Broderiptella) planigyrata (Guppy 1867)
Gastropoda - Heterostropha - Mathildidae
Mathilda informal sp. A Semper 1865
Gastropoda - Pyramidellidae
Turbonilla riosecana
Gastropoda - Trochidae
Calliostoma decipiens (Guppy 1867)
recombined as Calliostoma (Calliostoma) decipiens
see common names

Geography
Country:Trinidad and Tobago
Coordinates: 10.6° North, 61.1° West (view map)
Paleocoordinates:10.5° North, 59.6° West
Basis of coordinate:based on nearby landmark
Geographic resolution:outcrop
Time
Period:Neogene Epoch:Miocene
10 m.y. bin:Cenozoic 6
Key time interval:Late/Upper Miocene
Age range of interval:11.60800 - 5.33300 m.y. ago
Stratigraphy
Formation:Springvale Member:Melajo Clay
Regional section:Melajo River
Stratigraphic resolution:bed
Stratigraphy comments: 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
Lithology and environment
Primary lithology:shelly/skeletal poorly lithified conglomeratic "limestone"
Includes fossils?Y
Lithology description: Limestone with large mollusks, that graded out of a conglomerate.
Environment:shallow subtidal indet.
Geology comments: 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.
Taphonomy
Modes of preservation:body
Size of fossils:macrofossils
Preservation of anatomical detail:good
Collection methods and comments
Collection excludes:some macrofossils,some microfossils
Collection methods:selective quarrying,field collection
Reason for describing collection:taxonomic analysis
Museum repositories:PRI,USNM
Collection method comments: 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.
Taxonomic list comments: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.
Metadata
Database number:60408
Authorizer:A. Hendy Enterer:A. Hendy
Modifier:A. Hendy Research group:marine invertebrate
Collections that are a subset of this one:60637, 60638
Created:2006-05-14 12:52:13 Last modified:2013-11-25 13:37:23
Access level:the public Released:2006-05-14 12:52:13
Creative Commons license:CC BY
Reference information

Primary reference:

17317. P. Jung. 1969. Miocene and Pliocene mollusks from Trinidad. Bulletins of American Paleontology 55(247):293-697 [A. Miller/A. Hendy]