PallasAthene and rbeldua, you're both circling around it, and it's halfway between what you're both thinking, so I'll leave it up to you two to decide who's closer. . . it's a Shark Fossil - Megalodon Jaw. (The jaw measures 11 feet across and 8.5 feet high. There are over 180 teeth in the Megalodon jaw, including four teeth that are over 7 feet long. It took fossil hunter Vito "Megalodon" Bertucci nearly 20 years to find fragments of the Megalodon shark in the rivers of South Carolina, and 16 years to assemble the massive jaw.)
So one of you guys is up next! You decide!