Teen finds prehistoric mastodon jaw in southern Iowa
In this May 14, 2019 photo, a juvenile mastodon's jaw bone is displayed temporarily while unwrapped from its plastic covering, at the University of Iowa Paleontology Repository on the University of Iowa campus in Iowa City, Iowa. A teen searching for arrowheads in southern Iowa found the prehistoric jawbone of a mastodon. (Joseph Cress/Iowa City Press-Citizen via AP)