 In the southwest, around Bantry Bay and the mountains of MacGillycuddy's Reeks, is an area of substantially deformed, lightly metamorphosed Devonian-aged rocks.This partial ring of "hard rock" geology is covered by a blanket of Carboniferous limestone over the centre of the country, giving rise to a comparatively fertile and lush landscape.The west-coast district of the Burren around Lisdoonvarna has well-developed karst features.