Here is a sea urchin, Micraster, preserved in a block of flint. These specimens are best left as they are because they are ‘welded’ into the flint and cannot usually be removed from the rock.

Here is a sea urchin, Micraster, preserved in a block of flint. These specimens are best left as they are because they are ‘welded’ into the flint and cannot usually be removed from the rock.