Acid lab

This is where rocks are soaked in acid to make them break down and release the fossils they contain. The rock below is quite crumbly. As well as the large bones you can see there are many tiny bones, teeth and fragments waiting to be discovered.

The tubs contain a weak 10% solution of acetic acid. It gradually breaks down the sandstone, releasing pebbles, grit and fossils. Every few days the rocks are rinsed in a seive. It can take months to complete the process.

This seive contains the results of acid treatment after a rock has been rinsed in it. Mixed with pebbles and grit are lots of bones and teeth from small bats and rodents that lived in a cave 200 000 years ago. Acid treatment is especially useful with tiny fossils that would be destroyed by other methods of exposing them.