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6:30 p.m. Doors Open
7:00-9:00 p.m. Meeting and Presentation. All are welcome to attend

April’s guest speaker: Dr. Rich Busch, Professor of Geology, Department of Earth & Space Sciences, West Chester University

Fossils from the Ordovician Reedsville Formation at Swatara Gap, PA: Taphonomy, Age, Paleoecology, and Paleoecology

One of Pennsylvania’s most famous fossil collecting sites occurs in the Upper Ordovician, Reedsville Formation at Swatara Gap, PA. George W. Stose first described fossils from the site in 1930, and noted their showy state of preservation. Many spectacular specimens of trilobites, starfish, crinoids, brachiopods, mollusks, graptolites, ostracodes, bryozoa, and even algae were collected by many thousands of people in the decades thereafter. Unfortunately, for safety reasons, part of the site has been covered and collecting there has been forbidden since 1992. This means that the only way for paleontologists to study fossils from this site is to locate historic collections from it. One such collection was assembled by the author from 1967 to 1992. It has been much studied and is now being curated for donation to the State Museum of Pennsylvania. While the Swatara Gap site is perhaps best known for its trilobites, other groups will also be addressed to help you visualize the marine community that existed in east-central Pennsylvania about 454 million years ago. At that time the site was located on the east side of a narrow ocean basin, west of the eroding Taconic Mountains. West of the site, in central and western Pennsylvania, was the basin axis where abundant Triarthrus beckii trilobites lived in deeper, poorly oxygenated water. Further west, near Cincinnati, Ohio, the ocean basin shallowed again there existed a marine community very similar to the one at Swatara Gap.

 

Flexicalymene trilobite about 3 cm long.