Dunn County, Wisconsin, USA
Dikelocephalus trilobite fossil in dolomitic siltstone of the Cambrian St. Lawrence formation. Found in a small borrow pit near Gilbert Creek, south of Highway 29 west of Menomonee.
© Bill Cordua
Colfax Sandstone Quarry, Dunn County, Wisconsin, USA
Carbonate apatite in the form of phosphatic brachiopod shell fragments, in quartz sandstone.
U. W. River Falls students evaluating sand from the Cambrian Wonewoc Formation, exposed in a frac sand operation near Menomonie, Wisconsin, Spring, 2012.
View of the abandoned Colfax Quarry taken in November, 2017. This shows the well-exposed quartz sandstone of the upper part of the Cambrian Eau Claire Formation.