(D) As the bone slowly decays, groundwater gets inside the bone. The minerals in the groundwater are replaced with the chemicals in the bone. These minerals are the same as the surrounding rock. As the dinosaur bone turns into a fossil, it becomes a heavy, rock-like version of the original dinosaur. It is now officially called a fossil. When scientists look for dinosaur fossils, they look for specific rock types. Fossils are usually found in either shale,siltstone,mudstone, or sandstone