Fossils without alteration are rare. The original organic material is preserved without any chemical changes. The most common types of unaltered fossil are the hard parts of a living organism, like shells and teeth. In rare circumstances, preservation of soft parts may occur. An example is Dimo, a baby mammoth found in the tundra of Siberia. The ice preserved the mammoth’s body parts. Preservation was so good that paleontologists were able to determine that the baby mammoth died of blood poisoning. Another example is an insect which has been trapped in tree resins. When the resin fossilizes to form amber, it preserves the insect

A mammoth from Siberia

Ant in amber