A 13,600-year-old mastodon skull was uncovered in an Iowa creek, state officials announced this week.

Iowa’s Office of the State Archaeologist said in a social media post that archaeologists found the well-preserved skull on the side of a creek bed in Wayne County Wednesday at an excavation site they had been mining over the last 12 days.

Throughout the almost two-week dig, several mastodon bones were recovered, but the skull was something unique, as it was the “first-ever well-preserved mastodon (primarily the skull) that has been excavated in Iowa,” the post read.