Fossils

These rocks are part of the 340 million year old Castletown limestones. The large mound of rock in the centre of the photo (with the orange lichen on) represents the fossilised remains of an ancient reef. The reef was probably made up of algae and corals that lived in a shallow, tropical sea in the early Carboniferous period.





This is a more detailed photograph of a reef mound. The mound is made up of hundreds of tube-like structures. These are fossilised corals which lived in large colonies, forming the coral reef.

This fossil nautiloid was found in a quarry on Peel Hill, within the Dalby Group. It probably looked something like a squid with a long, straight shell (the ‘V’ shaped structure in the picture) and swam in the Iapetus Ocean 428 million years ago.






The two white cone-shaped structures in this block of limestone on Castletown beach are cross-sections through fossilised gastropod shells. These gastropods would have lived in a shallow marine environment in early Carboniferous times.