At the beginning of the Lower Carboniferous a tropical sea slowly moved northwards and covered the land. Reefs and limestone formed in this sea and many animals were preserved as fossils. Limestone now covers over 50% of Ireland.

350 million years ago Ireland was south of the Equator, submerged under a warm sea which contained many reefs and a large number of animals such as brachiopods, bryozoans, corals and gastropods. The sea was close to a large content called Laurussia that was made up of modern-day North America, Greenland, and Europe. The large continent Gondwana which was to the south was separated from Laurussia by a shallow ocean.

click on the prehistoric scenes