On Mon, 3 Feb 2014 09:07:22 +0000
Malcolm wrote:

They may or may not occur where there are volcanoes, but that is surely
irrelevant in 21st century High Wycombe! The two commonest causes are
old mine workings and the dissolving of limestone or sometimes sandstone
by the action of water.

The owner of the house was interviewed on R5 this morning, and said that
it was an old chalk mine. The house itself was on a concrete raft,
which could now be seen through the hole.

Some strata of chalk have been used for building stone in the past. My house
is built from it, known locally as "clunch".



Mike