The Cambrian Chickies Formation is a mapped bedrock unit in Pennsylvania, New Jersey, and Maryland.

It is named for Chickies Rock, north of Columbia, Pennsylvania along the Susquehanna River.

The Chickies Formation is described as a light-gray to white, hard, massive quartzite and quartz schist with thin interbedded dark slate at the top.

It is a rare metamorphic rock that has fossils; Skolithos is found throughout the formation.

The stone used to build the restrooms at Valley Forge National Historical Park is Chickies quartzite.