Geology

Naturally occurring alluvial clay containing a relatively large amount of calcium carbonate, used to counteract acidic soils and stabilise reclaimed mosslands.

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

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

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

Rocks that differ from the type native to an area.