Yellowstone National Park, Trace fossil

Trace_Fossil_1: The photo shows burrows from possibly a trilobite. This sample was collected from the Park Shale in Yellowstone National Park during a field investigation on Mount Holmes back in 2001, in which baseline paleontological information was gathered for the Yellowstone area.;
Megan Norr;
March 2016;
Catalog #20789d;
Original: Trace_Fossil_1