How do the bones stay preserved without decomposing?
Bone is made up of a mineral, Calcium Phosphate, which in many cases is hard to destroy. However, acids, like vinegar, will dissolve it easily (try putting a chicken bone in vinegar for a few days and seeing how soft it gets!). If the bones are NOT in an acid environment, there is a good chance that they will be preserved. Other minerals can also enter the bone while it is buried and help to preserve it.
