LGS 7 formerly Locality #7 - Logansport Formation (Paleocene to of the United States)

Also known as M 78

Where: Sabine County, Louisiana (31.6° N, 93.6° W: paleocoordinates 35.5° N, 75.2° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Logansport Formation (Midway Group), Danian to Danian (66.0 - 56.0 Ma)

• JAS has updated the age of this collection. "Logansport" was noted as a preoccupied name by Palmer and Brann (1965), who instead used the name "Halls Summit". Some confusion about the age of collections from this reference. While text states them to be Eocene, the Wilcox Group is in fact late Paleocene. No finer lithostratigraphic designation is stated in text, but Toulmin (1977) reports many of LeBlanc's taxa as belonging to the Logansport Formation of Sabine Parish, Louisiana. Logansport Formation lies betweent the Naborton and Hall Summit Formations, all of Thanetian age, and underlies further the Ypresian (Earliest Eocene) Marthaville, Pendleton and Sabinetown Formations.

• bed-level stratigraphic resolution

Environment/lithology: offshore; lithified, concretionary, brown, gray, yellow, calcareous siltstone

• No paleoenvironmental data stated. Appears to be a shallow shelfal environment. Enterer has designated it as "offshore siliciclastic".
• Yellowish brown septarian calcareous siltstone concretions

Size classes: macrofossils, mesofossils

Preservation: concretion

Collection methods: Collected by LaBlanc and Barry (1939).

Primary reference: R. J. LeBlanc and J.O. Barry. 1941. Fossiliferous localities of Midway Group in Louisiana. Bulletin of the American Association of Petroleum Geologists 25(4):734-738 [A. Miller/A. Hendy/A. Hendy]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 52196: authorized by Austin Hendy, entered by Austin Hendy on 30.07.2005, edited by Laurie Eccles

Creative Commons license: CC BY (attribution)

Taxonomic list

• Antiquated nomenclature. Reviewed by LaBlanc (1942), and some names are validated by Toulmin (1977).
Bivalvia
 Nuculanida - Nuculanidae
"Nuculana sp." = Nuculana1, "Leda sp." = Nuculana
"Nuculana sp." = Nuculana1 Link 1807 pointed nut clam
"Leda sp." = Nuculana Link 1807 pointed nut clam
 Carditida - Carditidae
 Pholadida - Corbulidae
Corbula sp. Bruguière 1789 clam
 Cardiida - Tellinidae
 Cardiida - Cardiidae
Cardium sp. Linnaeus 1758 cockle
 Mytilida - Mytilidae
Modiolus sp. Lamarck 1801 mussel
Modiolus (Brachidontes) "sp. B"2 Lamarck 1801 mussel
 Ostreida - Pinnidae
Gastropoda
 Lepetellida - Fissurellidae
? Diodora "sp. C"2 Gray 1821 snail
? Diodora "sp. D"2 Gray 1821 snail
? Fissurella sp. Bruguière 1789 snail
 Sorbeoconcha - Cassidae
Galeodea sp. Link 1807 snail
? Galeodea "sp. A"2 Link 1807 snail
 Sorbeoconcha - Ficidae
 Sorbeoconcha - Rostellariidae
 Neogastropoda - Costellariidae
Orthosurcula persa ribbed mitre
including O. persa n. var. pleasanthillensis
 Neogastropoda - Volutidae
Athleta petrosa Conrad 1833 volute
 Sorbeoconcha - Naticidae
Sinum sp. Röding 1798 moon snail
Sinum "sp. C"2 Röding 1798 moon snail
 Epitonioidea - Epitoniidae
Epitonium sp. Bolten 1798 wentletrap
 Architaenioglossa - Ampullinidae