Now known for its sports teams, Harleys, and beer, early Milwaukee County, Wisconsin was one of the nation’s leading producers of natural cement, and the fossils from its cement mines revealed one of the country’s most diverse assemblages of animals and plants of their age (Middle Devonian, ~385 million years ago). With the depletion of the cement rock, so went the ‘era of discovery’ of those fossils, but the few remaining exposures have become...
