Layer 3 (Ordovician of the United States)

Where: New York (43.3° N, 75.1° W: paleocoordinates 27.5° S, 53.1° W)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Orthograptus ruedemanni graptolite zone, Spillway Member (Rust Formation), Chatfieldian (453.8 - 451.0 Ma)

• bed-level stratigraphic resolution

Environment/lithology: marine; lithified, burrowed lime mudstone and lithified, graded siltstone

• This layer varies from 10 to 50 mm in thickness and has a complex history, as it includes at least two beds. The lower portion is a homogeneous calcilutite or micrite with scattered vertical burrows. The upper part is laminated dark and light calcisiltite and siltstone grading into mudstone.

Size class: macrofossils

Collected by Thomas E. Whiteley in 1990-1999; reposited in the MCZ

Collection methods: surface (in situ), mechanical,

Primary reference: C. E. Brett, T. E. Whiteley, P. A. Allison and E. L. Yochelson. 1999. The Walcott-Rust Quarry: Middle Ordovician Trilobite Konservat-Lagerst├Ątten. Journal of Paleontology 73(2):288-305 [M. Hopkins/M. Hopkins/M. Hopkins]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 181519: authorized by Melanie Hopkins, entered by Melanie Hopkins on 15.09.2016

Creative Commons license: CC BY (attribution)

Taxonomic list

 Trepostomida - Monticuliporidae
 Phacopida - Cheiruridae
Ceraurus pleurexanthemus Green 1832 trilobite
 Phacopida - Pterygometopidae
Calyptaulax callicephalus Hall 1847 trilobite
Achatella achates Billings 1860 trilobite
 Phacopida - Calymenidae
"Flexicalymene (cf. Flecicalymene) senaria" = Flexicalymene (Flexicalymene) senaria
"Flexicalymene (cf. Flecicalymene) senaria" = Flexicalymene (Flexicalymene) senaria Conrad 1841 trilobite
 Odontopleurida - Odontopleuridae
Diacanthaspis parvula, "Primaspis (cf. Primaspis) trentonensis" = Meadowtownella trentonensis, "Meadowtownella trentonensis" = Meadowtownella trentonensis
"Primaspis (cf. Primaspis) trentonensis" = Meadowtownella trentonensis Hall 1847 trilobite
"Meadowtownella trentonensis" = Meadowtownella trentonensis Hall 1847 trilobite
 Asaphida - Asaphidae
Isotelus gigas Dekay 1824 trilobite
 Homocrinida - Cincinnaticrinidae
 Homocrinida - Homocrinidae
Ectenocrinus simplex Hall 1847 Sea lily