The Swatara Gap Fossil Migration


About 12 years ago, success killed the Swatara Gap fossil locality in Lebanon County. Long known by fossil collectors as a place where exquisite Late Ordovician trilobites and the rare starfish Protasterina could be found, Swatara Gap was visited frequently by fossil enthusiasts. Unfortunately, the outcrop was adjacent to Interstate 81. Fossil seekers, some a little too zealous, removed so much material that the Pennsylvania Department of Transportation (PennDOT) had to declare the site off-limits in 1990. What was once uncovered by road construction now had become roadkill (so to speak) for safety’s sake.

In the summer of 2004, however, road construction and Swatara Gap fossils met again. As PennDOT initiated a reconstruction project for I-81, transportation officials came to the aid of fossil hunters. Working with the Pennsylvania Geological Survey, PennDOT removed some 20 triaxial dump truck loads of rock to nearby Swatara State Park. Trucks carrying fossil-bearing rock delivered more than 200 cubic yards of rock to the “Fossil Pit” off Swopes Valley Road (see location maps or link to map below).

Special thanks are given to John M. Bachman, Senior Project Manager for Highway Design at PennDOT, Brian Moore of Michael Baker Associates, Patricia Waidelich Riley of JMT Engineering, and William C. Friese, Park Manager, Bureau of State Parks, all of whom spent considerable effort to make this happen. For more information on how this occurred, see our web page on the Pennsylvania Natural Heritage Program and geology.

Update (October 2006) – It didn't take long for 200 cubic yards of rock to disappear (see photo, right). Visitors can expect to see only tiny pieces from the truckloads of fossil rocks that were moved to Swatara State Park. Fossil hunters can still look along the slopes of the site for indigenous fossils of the upper Mahantango Formation. For more information, see the description of the “Suedberg Fossil Site” in the Trail of Geology, Park Guide 16.

Note to visitors to the Swatara State Park Fossil Pit

If you visit Swatara State Park and the fossil pit, please be considerate of others who will visit after you. Please don’t remove rocks for off-site fossil extraction. Please only take a few specimens with you to allow others to enjoy looking for fossils for years to come. As always, eye protection should be worn when using rock hammers and chisels.

More information about Swatara Gap