Rocks which have formed on the beds of seas are called sedimentary rocks and often contain fossils. The rock exposed on the seashore at Portush looks like basalt but it contains fossils! Because of this, scientists thought that basalt must be a sedimentary rock. But later it was shown that Portrush rock was not basalt at all but was instead a sedimentary shale which had been baked hard by molten lava. Today, scientists accept that basalt is formed from volcanic lava which has cooled and turned solid.
Some of the fossils which were discovered in Portrush are on display in the Portrush Coastal Zone. In order to safeguard this nature reserve, visitors are asked not to remove specimens.
for further information and places of interest near Portrush.