The Spence Shale Lagerstätte


The Spence Shale is the middle member of the Langston Formation in southeastern Idaho and northeastern Utah. It is exposed in the Bear River Range, the Wasatch Range and the Wellsville Mountains. It is known for its abundant Cambrian trilobites and the preservation of Burgess Shale-type fossils.

The type locality is Spence Gulch in southeastern Idaho, near the town of Liberty. It was first described by Charles Doolittle Walcott in 1908.