Brandon Bridge Formation

The Brandon Bridge Formation is a Silurian dolomite formation exposed in a quarry near Waukesha, Wisconsin, roughly four hundred and thirty five million years old, preserving the Waukesha Biota, an unusual assemblage of soft bodied marine animals, including rare early arthropods, fossilized in a reef associated lagoon setting rarely preserved elsewhere in rocks of this age. The quarry's fossils have offered a rare window onto soft bodied marine life in the middle of the Paleozoic era.