A teenager got a big surprise while looking for arrowheads on an Iowa farm.

Instead of any arrowheads, the teen found a 30-inch jaw bone of a mastodon -- a prehistoric hairy elephant, related to the mammoth.

Mastodons went extinct about 10,000 years ago, according to LiveScience.

A paleontology team from the University of Iowa (UI) picked up the jaw bone and other related bones over the weekend, according to WHOTV.

“We were notified a couple of weeks ago that somebody had found a fossil in the middle of a small river on the property,” Tiffany Adrain, the head of the UI Paleontology Repository told the outlet.

“It was actually a high school student who had found the object, and the landowners contacted us and notified us [and] sent us photographs.

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