Trilobites of the Rust Formation, Trenton Group (Walcott-Rust Quarry), New York

Locality: Walcott-Rust Quarry, Gray’s Brook, Russia, Herkimer County, New York, U.S.A.
Stratigraphy: Trenton Group, Rust Formation, Spillway member
Age: Upper Ordovician (460-443 million years ago)

The limestone deposits of The Walcott-Rust Quarry contain abundant examples of at least 18 species of trilobites, most of which have been studied extensively. The four most common species found are Ceraurus pleurexanthemus, Flexicalymene senaria, Isotelus gigas and Meadowtownella trentonensis.  Specimens of Ceraurus pleurexanthemus and Flexicalymene senaria were of particular interest to Charles D. Walcott. His study of thin sections of these trilobites revealed for the very first time, preserved biramous appendages inside the carapaces. More recently, Brett et al. (1999) conducted detailed examinations of the sedimentary beds and trilobite fauna, leading to theories of paleo-current direction and the conditions and speed of burial of the fauna.