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.
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.