Geologically the site is located on limestone bedrock, formed in a shallow tropical sea around 340million years ago. Natural geological features such as a relict river bed, associated dolines and sinkholes across the Lost Valley, where a river sank and disappeared underground. The fossils you can see embedded in limestone around the site are further evidence of this this amazing pre-glacial landscape would have looked. About 13,000years during the last Ice Age, huge boulders of sandstone were deposited by glaciers on the limestone bedrock of Cavan Burren. These boulders are known as ‘Glacial Erratics’ and you will see lots of them throughout the park. They sit on pedestals of limestone making them pretty distinctive. The landscape you see today has been greatly altered by the Ice Age. Just after c.4000 BC at the very beginning of the Neolithic period it is understood that the first farmers arrived at Burren. They cleared forestry and created settlements where they lived, worshiped and died. Remains of these settlements are evident from the magnificent archaeological monuments.