A new study has discovered that ancient inhabitants not only ate fresh water shellfish, but carved into their shells as well as used them as tools. Researchers discovered carvings 540,000 and 430,000 years ago. This could be the oldest art work from human kind. Researchers are still determining this by doing a carbon dating examiniation on the shells. Carbon dating is used to determine how old something is by analyzing the carbon done to the protons and neutrons. By counting them they can determine how old the shell carvings are by how many neutrons have been displaced.