Gaj beds - Near Karachi (Miocene of Pakistan)

Where: Pakistan (24.9° N, 67.1° E: paleocoordinates 19.2° N, 66.4° E)

• coordinate stated in text

• local area-level geographic resolution

When: Gaj Formation, Early/Lower Miocene (23.0 - 16.0 Ma)

• STRATIGRAPHIC RELATIONS: From the lower Gaj beds, which regionally overlie the Nari beds (Oligocene) and are overlain by the Middle-Late Miocene Mekran beds. AGE: The Gaj Formation is primarily Burdigalian, except for the basal parts (Naseem et al. 1996). Larger foraminifera are characterized by Miogypsina gunteri and M. thecideaeformis zones (Aquitanian and Burdigalian, early Miocene) (Kureshy, 1982). STRATIGRAPHIC POSITION: from the lower Gaj beds.

• group of beds-level stratigraphic resolution

Environment/lithology: poorly lithified limestone

• ENVIRONMENT: Not stated in text, but lithological descriptions suggest range from deep subtidal to shallow subtidal.
• SPECIFIC LITHOLOGY: In the Karachi area, the Gaj Formation includes the Metan Clay (nodular clay with thin limestone intercalations), Jhill Limestone (cream-colored, nodular, reefal), and the Talawa Limestone (sandy, with fossil fragments and cross-beds). LITHIFICATION: Poorly-lithified, based on figured specimens.

Size class: macrofossils

Collected by Vredenburg

Collection methods: surface (in situ),

• COLLECTORS: Multiple collectors including W. Blanford, Wynne, Hira Lal, Ram Singh, and Noetling (staff of Geological Survey of India) during the early 1900's. REPOSITORY: Geological Survey of India, with voucher specimens possibly at the BMNH.

Primary reference: E. Vredenburg. 1925. Description of Mollusca from the post-Eocene Tertiary formation of north-western India: Cephalopoda, Opisthobranchiata, Siphonostomata. Memoirs of the Geological Survey of India 50(1):1-350 [A. Hendy/A. Hendy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 77164: authorized by Austin Hendy, entered by Austin Hendy on 21.12.2007

Creative Commons license: CC BY (attribution)

Taxonomic list

• COVERAGE: Exhaustive for gastropoda, bivalvia, and scaphopoda. NOMENCLATURE: Antiquated, but from an authoritative publication, with use of species and subgenus resolution assignments. Nomenclature can be updated through reference to Harzhauser and Swarko publications.
Cephalopoda
 Nautilida - Aturiidae
Aturia aturi Basterot 1825 nautiloid
Gastropoda
 Sorbeoconcha - Cypraeidae
"Cypraea (Bernayia) humerosa" = Barycypraea humerosa, "Cypraea prunum" = Callistocypraea (Miolyncina) prunum
"Cypraea (Bernayia) humerosa" = Barycypraea humerosa Sowerby 1839 cowry
"Cypraea prunum" = Callistocypraea (Miolyncina) prunum Sowerby 1839 cowry
SUBSPECIES: Cypraea prunum nasuta
 Sorbeoconcha - Strombidae
Strombus sedanensis Martin 1899 conch
 Sorbeoconcha - Ranellidae
Gyrineum biturberculare1, "Ranella (Apollon) morrisi" = Apollon morrisi
"Ranella (Apollon) morrisi" = Apollon morrisi d'Archiac 1854 triton shell
 Sorbeoconcha - Cassidae
Cassidaria desori d'Archiac and Haime 1854 snail
 Neogastropoda - Volutidae
"Lyria jugosa" = Lyria (Harpeola) jugosa Sowerby 1839 volute
Athleta (Volutospina) dentata Sowerby 1839 volute
SUBSPECIES: Athleta (Volutospina) dentata sykesi
 Neogastropoda - Muricidae
Muricopsis exhexagonus Vredenburg 1925 murex snail
Murex (Acupurpura) verbeeki Martin 1895 murex snail
Murex (Haustellum) tchihatcheffi d'Archiac and Haime 1854 murex snail
 Neogastropoda - Olivellidae
Agaronia pupa1 Sowerby 1840 snail
 Neogastropoda - Borsoniidae
"Surcula tuberculata" = Asthenotoma tuberculata
"Surcula tuberculata" = Asthenotoma tuberculata Gray 1839 snail
SUBSPECIES: Surcula tuberculata voyseyi
 Neogastropoda - Nassariidae
Nassa (Hima) vicaryi d'Archiac 1850 snail
 Neogastropoda - Buccinidae
Metula martini Vredenburg 1925 true whelk
Hindsia granosa Sowerby 1840 true whelk
"Tritonidea (Cantharus) bucklandi" = Cantharus bucklandi d'Archiac 1850 true whelk
Nassa (Telasco) falconeri d'Archiac and Haime 1850 true whelk
 Neogastropoda - Mitridae
"Mitra (Cancilla) rembangensis" = Cancilla rembangensis
"Mitra (Cancilla) rembangensis" = Cancilla rembangensis Martin 1906 mitre shell
Bivalvia
 Cardiida - Cardiidae
"Cardium (Discors) triforme" = Discors triforme2
"Cardium (Discors) triforme" = Discors triforme2 Sowerby 1840 cockle
 Pectinida - Pectinoidae
"Pecten (Chlamys) feddeni" = Chlamys feddeni2, "Pecten (Chlamys) senatorius" = Mimachlamys senatoria2, "Pecten (Aequipecten) scabrellus" = Chlamys scabrellus2, Pecten (Chlamys) articulatus2, "Pecten (Amussiopecten) subcorneus" = Amussium subcorneum2
"Pecten (Chlamys) feddeni" = Chlamys feddeni2 Vredenburg 1928 scallop
"Pecten (Chlamys) senatorius" = Mimachlamys senatoria2 Gmelin 1791 scallop
SUBSPECIES: Pecten (Chlamys) senatorius soomrowensis
"Pecten (Aequipecten) scabrellus" = Chlamys scabrellus2 Lamarck 1819 scallop
Pecten (Chlamys) articulatus2 Sowerby 1840 scallop
"Pecten (Amussiopecten) subcorneus" = Amussium subcorneum2 d'Archaic and Haime 1854 scallop