The term limestone is commonly used to describe calcareous strata that are harder and older than chalk. As a guide to their distribution it may be said that in the British Isles the chalk areas occur in east and south-east England where the young rocks are exposed; next, to the north and west, are situated the older Oolitic limestones—rather soft yellowish stone so beautifully used for building in the Cotswolds, for example; and farther north and west, in a larger arc, are to be found the Carboniferous or Mountain limestones, e.g. the Mendips, Gower, the Great Orme, the Craven district of Yorkshire, and the Derbyshire Dales. Elsewhere in north and west Britain the limestones are small in extent and most of the rocks are ancient siliceous strata. In Ireland, however, there is a great deal of Carboniferous limestone; but little is free from peat covering which is maintained as an organic ground cover in that very wet climate. In general, much of the geographical variability of lowland calcareous grassland over the country as a whole may be accounted for by differences in climate.
- 976 reads
