Hamstone

Golden-brown sedimentary stone, from Ham Hill in Somerset.

Karst cave

The most common type of cave, formed by the solution of carboniferous rocks by the action of rainwater.

Keuper Marl

Now deprecated term for multiple layers of mudstone and siltstone that occur beneath parts of the English Midlands and beyond.

The Great Stone, Stretford

Grade II listed structure in Stretford, Greater Manchester, probably the base of an Anglo-Saxon cross shaft.

Elland flags

Sandstones interbedded with mudstones and siltstones in the Lower Coal Measures of West Yorkshire, once extensively quarried.

Flockton Collieries

Flockton Collieries comprised several pits, some started before 1700, around Flockton and Middlestown between Wakefield and Huddersfield in the West Riding of Yorkshire.

Cannel

Type of bituminous coal.