A relatively new geochemical technique is now being used to determine a fossil bone’s original burial site. This technique analyzes the rare earth elements present in bones and the surrounding sedimentary rock (rare earth elements are normally present in rocks and soil in small amounts). Dinosaur bones contain calcium phosphate (apatite) and proteins. When the animal dies, the protein rots away. After burial, the calcium phosphate reforms into a slightly different crystalline structure, and rare earth elements in the surrounding soil may replace some of the calcium ions in the bone structure. The relative proportions of the different rare earth elements present in a bone are a signature that is established soon after burial; and they remain fixed. If the rare earth element signature in a bone matches the surrounding sediment, it is likely that this was the original site of burial. However, if the signature of the bone is different from the surrounding sediment, then it is likely the bone was transported from its original burial site.