Schram Quarry (Cretaceous of the United States)

Where: Dixon County, Nebraska (42.6° N, 96.7° W)

• Paleocoordinates: 48.2° N, 46.8° W (Wright 2013)

• coordinate stated in text

• small collection-level geographic resolution

When: Greenhorn Formation, Cretaceous (145.0 - 66.0 Ma)

• formation-level stratigraphic resolution

Environment/lithology: open shallow subtidal; peloidal, shelly/skeletal, black, gray, green, carbonaceous chalk

• The depth of water was probably between 30 and 90 m (Hattin, 1975). Diverse invertebrate assemblages in various parts of the Greenhorn Formation suggest normal salinity and the presence of certain cosmopolitan species indicates connection of the North American epicontinental seaway with the world ocean during the lower Turonian (Hattin, 1975).
• The enclosing matrix conforms with Hattin's (1975) description of shaly chalk which is common throughout the Greenhorn sequence and is composed of more or less laminated, impure carbonate, olive gray to olive black in color. The principal components are coccolithophore skeletal debris, inoceramid fragments, planktonic foraminiferans, and fecal pellets. Other organics, pyrite and fine-grained terrigenous detritus are commonly present. Fish scales, vertebrate skeletal debris and bivalve fragments are common in the rock slab that contained the specimen. The skeleton lay directly on top of numerous inoceramid bivalves (Mytiloides labiatus).

Size class: macrofossils

Preservation: adpression

Reposited in the USNM

Collection methods: quarrying, mechanical, acetic,

Primary reference: G. Arratia and J. Chorn. 1998. A New Primitive Acanthomorph Fish from the Greenhorn Formation (Late Cretaceous) of Nebraska. Journal of Vertebrate Paleontology 18(2):301-314 [S. Peters/S. McMullen/S. McMullen]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 133595: authorized by Shanan Peters, entered by Sharon McMullen on 18.09.2012

Creative Commons license: CC0 (CC0)

Taxonomic list

Show authors, comments, and common names
Actinopteri
 Acanthomorphata - Ferrifronsidae
Acanthichthys major n. gen. n. sp.
Acanthichthys major n. gen. n. sp.
Bivalvia
 Myalinida - Inoceramidae
Mytiloides labiatus
Mytiloides labiatus Schlotheim 1813 clam