Clay, with sand or gravel, that has had water added and mixed thoroughly so that it becomes watertight. The term was coined in 1762 by the canal builder James Brindley, although the use of such clay in dams goes back to Roman times Found on https://www.encyclo.co.uk/local/21221
Clay, with sand or gravel, that has had water added and mixed thoroughly so that it becomes watertight. The term was coined in 1762 by the canal builder James Brindley, although the use of such clay in dams goes back to Roman times