Slickensides

Slickensides is the name of a farm in the High Peak district of Derbyshire, of a cheese prepared at the farm, and of the old lead mine that lies beneath it. It is also the geological term for a particular rock formation which results in the trapping of energy behind it. Such energy can be dangerously explosive when released.

All this Inspector Brunt has occasion to expound on a visit there in 1911...