HE soft, yellowy limestone that immediately says ‘Cotswolds’ is, confusingly, only one element of a complex layering of Jurassic rock that developed over a 70 million-year period and stretches in a north-easterly spine from the Dorset coast to Yorkshire’s North Sea shores. For instance, the south-eastern side of the Cotswolds, beyond Cirencester, is part of the Great Oolite group from the Middle Jurassic period, rocks that are more than 164 million years old; this includes a thick clay bed
