Trilobites of the Walcott-Rust Quarry
last revised 06 August 2009 by S.M. Gon III
Locality: Trenton Falls, Herkimer County, central New York, USA
Stratigraphy: Spillway Member, Rust Formation, Trenton Group
Age: Late Ordovician (Shermanian [~Sandbian]), ca 455(?) Mya
Harvard MCZ WRQ image current quarry
current work 2
(left) Original Walcott-Rust Quarry site (right) Quarry excavations 
 During the Late Ordovician, North America (Laurentia) was tropical, with NY about 20 deg S of the paleoequator.

Location of the Walcott-Rust locality today
Location in the Late Ordovician

What is today referred to as the Walcott-Rust Quarry was discovered in 1870 by Charles Doolittle Walcott (then 20 years of age) years before his discovery of the more famous Burgess Shale in British Columbia, Canada. Because one layer of the locality yields specimens preserved with calcified appendages, they provided the first documentation of the biramous limbs of trilobites (Walcott 1876). Located near the farm of William Rust, Walcott and Rust collected from the quarry and sold their collections to the Museum of Comparative Zoology at Harvard University. There, museum director Louis Agassiz convinced Walcott to pursue paleontology as a career. The locality is famous for bearing well-preserved, fully articulated fossils from the lower third of the formation.  Found here are three species of the more common trilobites of the Trenton Group: (Ceraurus pleurexanthemus, Flexicalymene senaria, and Isotelus gigas) but also fourteen other species of rare and uncommon trilobites. Trilobites with preserved appendages from the locality include Ceraurus pleurexanthemus and Flexicalymene senaria. As in other konservat-lagerstatten, there is evidence of rapid burial of living communities, entombing and preserving them. The Walcott-Rust locality has been described as the single richest and most varied source of trilobites in the New York Trenton Group limestones, if not the entire suite of New York Paleozoic rocks. This richness, coupled with the extraordinary preservation of trilobite appendages qualifies the locality as an exceptional trilobite site.

Ceraurus pleurexanthemus
Green 1832
Flexicalymene senaria
(Conrad 1841)
Bumastoides holei
(Foerste 1920)
Hypodicranotus striatulus
(Walcott 1875)

Isotelus gigas
DeKay 1824
Sphaerocoryphe robusta
Walcott 1875
Undetermined proetid

Meadowtownella trentonensis
(Hall 1847)

via Brett et al 1999

Suborder Illaenina
Family Illaenidae
Bumastoides decemsegmentus (Author, date?)
Bumastoides holei
(Foerste 1920)
Bumastoides porrectus (Raymond 1925)
Nanillaenus americanus (Billings 1859)

Superfamily Asaphoidea
Family Asaphidae
Isotelus gigas Dekay 1824
Isotelus walcotti Ulrich in Walcott 1918
Superfamily Remopleuridoidea
Family Remopleurididae
Hypodicranotus striatulus (Walcott 1875)

Suborder Cheirurina
Family Cheiruridae
Subfamily Cheirurinae
Ceraurus pleurexanthemus Green 1832
Gabriceraurus cf dentatus (Raymond & Barton 1913)
Subfamily Deiphoninae
Sphaerocoryphe robusta Walcott 1875
Suborder Phacopina
Superfamily Phacopoidea
Family Pterygometopidae
Achatella achates (Billings 1860)
Calyptaulax eboraceous
Calyptaulax callicephalus
(Hall 1847)
Suborder Calymenina
Family Calymenidae
Flexicalymene senaria (Conrad 1841)

Suborder Lichina
Family Lichidae
Amphilichas cornutus (Clarke 1894)
Amphilichas conifrons Ruedemann 1916
Amphilichas inaequalis (author, date?)

Family Odontopleuridae
Meadowtownella trentonensis (Hall 1847)
Diacanthaspis parvula (Walcott 1877)

Superfamily Proetoidea
Family Proetidae
undetermined proetid

Achatella acates
image courtesy Dave Comfort
Many thanks to Steve Hess, Dave Comfort, Jim Cook and others for advice, images, and info regarding this page.

Some Walcott-Rust references: 

Brett, C.E., T.E. Whiteley, P.A. Allison, & E.L. Yochelson. 1999. The Walcott-Rust Quarry: Middle Ordovician trilobite konservat-lagerstatten. Journal of Paleontology 73(2):288-305. [Note: since this publication, the divisions of the Ordovician have been refined and the Rust Formation is considered part of the lower Upper Ordovician, rather than upper Middle Ordovician. Images of Meadowtownella and the unidentified proetid above are via this citation (Brett et al 1999).]

Walcott, C.D. 1876. Preliminary notice of the discovery of the remains of the natatory and brachial appendages of trilobites. advanced print. Dec. 1876. 28th Annual Report New York State Museum Natural History, 1879:89-92.

Whiteley, T.E., G. J. Kloc & C.E. Brett. 2002. Trilobites of New York. Cornell University Press.

Harvard Museum of Comparative Zoology Walcott-Rust page. (several of the images of trilobite specimens above are courtesy MCZ website, as well as the site locality image)

Related locality: Rochester Shale, NY
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