Scientists believe that Ireland was so densely wooded that the great elk became extinct because its antlers kept getting caught in tree branches.
Early settlers to Ireland arrived on northern shores, keeping close to both the coast and fresh water supplies.
Mount Sandel near Coleraine, Co.Derry has been established as dateing from 7000 - 6500 B.C.
These were stone-age people, using edges and flint to cut and hunt.