Chiefly in Leitrim, but extending into the several counties round, several hill-groups rise, separated by valleys often containing considerable lakes.
The soils of Ireland are commonly good loams, and are rarely deficient in lime, owing to the diffusion of pebbles of limestone in the glacial drifts. But the Old Red Sandstone and the quartzite mountain lands are naturally barren, except where covered by glacial material. In upraised wind-swept areas the Carbonifer- ous Limestone maybe practically devoid of soil, and karst conditions may prevail. Peat occupies large areas of the central plain, and furnishes a cheap fuel to the inhabitants. Experiments are being made in the development of forests on boglands that have been cut away.