 In the southwest , around <unk> Bay and the mountains of <unk> 's <unk> , is an area of substantially deformed , but only lightly <unk> , Devonian @-@ aged rocks . This partial ring of " hard rock " geology is covered by a blanket of <unk> limestone over the centre of the country , giving rise to a comparatively fertile and lush landscape . The west @-@ coast district of the <unk> around <unk> has well @-@ developed <unk> features . Significant <unk> lead @-@ zinc <unk> is found in the <unk> around <unk> and <unk> . 
