The island's "solid geology" is primarily , featuring extensive limestone that has led to the formation of over 3,500 karst features . Roughly 15,000 years ago , Ireland was entirely covered by thick glaciers that scraped away soil to leave flat limestone stretches. Ireland Country Profile - National Geographic Kids

Ireland , famously known as the due to its lush green hills and valleys, is characterized by a central lowland of limestone covered in glacial deposits, surrounded by coastal mountain ranges. Geological and Natural Landscape