Tens of thousands of fossils were excavated in what is now Sabercat Historical Park and nearby locations, and this discovery was documented by Dr. Don Savage from the University of California, Berkeley. Because of this remarkable unearthing, that time period is known as the Irvingtonian North American Land Mammal Age, after Fremont’s Irvington District. Very few complete skeletons were found there, and the skeletons shown from other North American sites illustrate species that were also found here. Irvingtonian mammals included animals that survive nearly unchanged from their Ice Age ancestors, including ground squirrels, raccoons, gophers, and coyotes. On the geologic timescale, the Irvingtonian Era is recent history: the dinosaurs had been extinct for 63 million years, and the continents were arranged the same as they are today.