Borehole 927 - Ilaro Fm (Eocene of Nigeria)

Where: Nigeria (6.7° N, 3.2° W: paleocoordinates 2.1° N, 9.0° W)

• coordinate based on nearby landmark

• small collection-level geographic resolution

When: Ilaro Formation, Lutetian (47.8 - 41.3 Ma)

• STRATIGRAPHIC RELATIONS: From the Ilaro Fm, which overlies the Ewekoro Fm (Paleocene) and is unconformably overlain by Oligocene-Pleistocene coastal plain sands. THICKNESS: From single horizon of unknown thickness, within formation that is approximately 220 ft thick. AGE: Probably Middle Eocene, but debated. A fish fauna (White 1926, 1955) suggests Middle Eocene; mollusca based on similarity with regional assemblages of Newton (1922) and Eames (1957) suggests a Late Eocene age; Berggren (1960) however suggests a Lutetian (Middle Eocene) age on the basis of foraminifera; Reyment (1963), suggests Early Eocene. An intermediate age of Lutetian is assigned for the collection by the enterer. STRATIGRAPHIC POSITION: From 370 ft within borehole, which lies 135 ft below the top of the formation.

• bed-level stratigraphic resolution

Environment/lithology: offshore; shale

• ENVIRONMENT: Not reported in text, but apparently siliciclastic and relatively offshore.
• SPECIFIC LITHOLOGY: Shales, silts, and fine-grained argillaceous sands. LITHIFICATION: Unknown.

Size class: macrofossils

Collection methods: COLLECTOR: Not reported, but presumably the Geological Survey of Nigeria. REPOSITORY: Not stated, but presumably the Geological Survey of Nigeria of the BMNH.

Primary reference: H. A. Jones and R. D. Hockey. 1964. The geology of part of south-western Nigeria. Geological Survey of Nigeria Bulletin 31:1-101 [A. Hendy/A. Hendy/A. Hendy]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 77257: authorized by Austin Hendy, entered by Austin Hendy on 07.01.2008, edited by Jocelyn Sessa

Creative Commons license: CC BY (attribution)

Taxonomic list

• COVERAGE: Exhaustive for gastropoda, bivalvia, and scaphopoda. NOMENCLATURE: Somewhat antiquated nomenclature from non-authoritative publication, but using subgenus and species-resolution assignments. Identified by Reyment (1952, unpublished report).
 Rotaliina - Cassidulinidae
Ceratobulimina sp. Toula 1915
 Planorbulinacea - Cibicididae
 Planorbulinacea - Planulidae
Planulina sp. d'Orbigny 1826
 Buliminacea - Uvigerinidae
Uvigerina sp. d'Orbigny 1826
 Discorbacea - Discorbidae
Discorbis sp. Lamarck 1804
 Discorbacea - Eponididae
 Nonionacea - Nonionidae
Nonion sp. Monfort 1808
 Rotaliina - Bolivinidae
 Globigerinaceae - Globigerinidae
 Globigerinaceae - Globorotaliidae
 Globigerinina - Chiloguembelinidae
 Globigerinina - Truncorotaloididae
 Nodosariacea - Nodosariidae
Robulus sp. Montfort 1808
 Podocopida -
 Podocopida - Bythocyprididae
 Podocopida -
 Podocopa - Loxoconchidae
 Arcida - Glycymerididae
 Arcida - Noetiidae
 Cardiida - Cardiidae
 Nuculida - Nuculidae
Nucula costaeimbricatis Newton 1922 nut clam
 Neogastropoda - Buccinidae
Pseudoliva (Buccinorbis) kitsoni Newton 1922 true whelk
 Neogastropoda - Turridae
Turcula (Surcula) africana Newton 1922 turrid
Eopleurotoma nigeriensis Newton 1922 turrid
 Stromboidea - Strombidae
Tibia bidigitata true conch
 Stromboidea - Rostellariidae
Cyrtulotibia unidigitata Newton 1922 snail
 Naticoidea - Naticidae
Sinum nigeriense moon snail
 Cypraeoidea - Pediculariidae
Eovolva nigeriensis Newton 1922 snail
 Calyptraeoidea - Calyptraeidae
Crepidula (Concavimargo) falconeri Newton 1922 slipper shell
 Sorbeoconcha - Turritellidae
 Architectonicoidea - Architectonicidae
 Dentaliida - Dentaliidae
Dentalium sp. Linnaeus 1758 tusk shell
 Squatiniformes - Squatinidae
Squatina sp. Dumeril 1806 angel shark
 Rhinopristiformes - Pristidae
Pristis lathami Galeotti 1837 sawfish
 Myliobatiformes - Myliobatidae
Myliobatis toliapicus Agassiz 1843 eagle ray
 Lamniformes - Otodontidae
"Odontaspis koerti" = Otodus koerti
"Odontaspis koerti" = Otodus koerti Stromer 1910 mackerel shark
Odontaspis koerti and Odontaspis koerti itoriensis
 Lamniformes - Odontaspididae
Odontaspis cf. substriata sand tiger shark
 Carchariniformes - Carcharhinidae
Galeocerdo semilevis White 1926 tiger shark
 Carchariniformes - Triakidae
Galeorhinus falconeri White 1956 school shark
 Orectolobiformes - Ginglymostomatidae
Ginglymostoma obliquum, "Ginglymostoma serra" = Nebrius serra
Ginglymostoma obliquum Leidy 1877 nurse shark
Ginglymostoma obliquum oshosunensis
"Ginglymostoma serra" = Nebrius serra Leidy 1877 nurse shark
 Acipenseriformes -
 Scombriformes - Trichiuridae
 Siluriformes - Ariidae
Arius russi White 1926 Ariid catfish
 Scleractinia - Turbinoliidae
Turbinolia sp. Lamarck 1816 stony coral
 Miliolida - Miliolidae
Quinqueloculina sp. d'Orbigny 1826
Sigmoilina sp. Schlumberger 1887