Turrilitidae ("Tower Stones") is a family of extinct heteromorph ammonite cephalopods. All members had shells that coiled helically that tended to resemble auger shells, hence the name "Tower Stones." The ecological roles turrilitids played is largely unknown, as experts are still speculating what niches they filled. Some, such as Didymoceras, are suspected of floating in the water column, while others, such as Turrilites, are believed to have been bottom-dwellers.
Although they were diverse, with a worldwide distribution, the turrilitids, along with all other ammonites, did not survive the Cretaceous-Tertiary Extinction event.