Douglas County near Lawrence (Carboniferous of the United States)

Where: Kansas (38.9° N, 95.2° W: paleocoordinates 3.2° S, 28.2° W)

• coordinate based on nearby landmark

• local area-level geographic resolution

When: Haskell Limestone Member (Lawrence Formation), Kasimovian (307.0 - 303.7 Ma)

• Basal Virgilian. The nodules occur immediately above the Haskell limestones, which are of marine origin, and at the base of the Robbins shale originated in brackish waters.

• group of beds-level stratigraphic resolution

Environment/lithology: coastal; lithified, nodular limestone

• According to Miller and Swineford (1957), the nodules are genetically linked to the Haskell limestone and the fossils fauna is different from that in the Robbins shale. They concluded that the nodules were formed in a nearshore environment, probably within shallow marine basins formed in a subtropical and humid area. The bottom condition of these basins was probably quiet, anoxic, without strong currents nor overturning at the time the nodules formed.

Size class: macrofossils

Preservation: cast

Reposited in the MNHN

• The nodules were collected in a concretion-rich area that was first reported and studied by Twenhofel and Dunbar (1914). An extensive paleoecological, stratigraphical and geochemical study about these nodules was later undertaken by Miller and Swineford (1957). Some specimens in Museum of Natural History, University of Kansas.

Primary reference: C. Poplin. 1984. Lawrenciella schaefferi n. g. n. sp. (Pisces: Actinopterygii) and the use of endocranial characters in the classification of the Palaeonisciformes. Journal of Vertebrate Paleontology 4(3):413-421 [M. Clapham/M. Clapham]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 117102: authorized by Matthew Clapham, entered by Matthew Clapham on 15.09.2011

Creative Commons license: CC BY (attribution)

Taxonomic list

Chondrichthyes
 Ctenacanthiformes - Ctenacanthidae
Ctenacanthus sp. Agassiz 1837 elasmobranch
Cladodus sp. Agassiz 1843 elasmobranch
Actinopteri
 Palaeonisciformes -
Lawrenciella schaefferi n. gen. n. sp.
Lawrenciella schaefferi n. gen. n. sp. Poplin 1984