1.56" (3.97 cm) Brachiosaurus tooth from the Morrison Formation of Carbon County, Wyoming. 155-147 million years old. 

This tooth has a twist in it, which is not present in Camarasaurus. The enamal is present on the root of the tooth, which differs from Camarasaurus. Because of these, I believe this tooth to be Brachiosaurus. There is some gap fill and the tooth has been pieced back together.