Minnesota’s giant beaver, weighing over 300 pounds in life, was discovered in July 1938 by a crew of WPA workers who were building a road in the Mississippi River Gorge, Hidden Falls Park, St. Paul. Castoroides was preserved when it was buried 10, 320 years ago by collapse of a limestone ledge under which it was resting. The limestone ledge was the lip of St. Anthony Falls when it was located 6.3 miles downstream of its present location in Minneapolis.

The skeleton of the giant beaver holds special interest for me as it’s description was the subject of my first scientific presentation and publication through the Minnesota Academy of Science, vol. 30, No. 1, 1962.
– Bruce Erickson, Fitzpatrick Chair of Paleontology