Fossils are the product of organic materials which have been preserved over a long period of time. It is actually very rare for living organisms to be fossilised, as most will simply decay once they die. However, fossilisation can occur under special circumstances. Fossilisation is when the soft parts of a living organism, (which decay the fastest), decompose and leave the skeletal remains of the organism behind.

Portrush Fossils
Portrush Fossils at Lansdowne

If sediment gathers above and around the organism’s remains, over time – and with a large amount of sediment – the weight and pressure will cause the organism to fossilise and we are left with the ‘shell’ of the original organism part which can then be preserved by palaeontologists.


Fossils are an excellent way to learn about the past and the types of animals and plants which were alive. A very important type of fossil is a ‘coprolite’- fossils of faeces. These tell us of the diet and ecology of animals and can, for example, tell us the diet of dinosaurs and extinct animals. The most expensive coprolite is of a Viking human and is estimated at £30, 000!

Portrush is a fantastic site for fossils and they are a major part of what makes the area so important to Scientists as an Area of Special Scientific Interest (ASSI). The most common type of fossil found in Portrush is the ammonite – spiral fossils of animals which are related to other cephalopods such as squids or octopi. The remains we can see today were the shells of these animals, which became extinct around the same time as the dinosaurs. The biggest ammonite was found in Germany and is almost 2 metres across but most ammonites are small enough to fit in your hand.

The White Rocks are also popular for finding fossils – most of which are the tubular belemnites which were also cephalopods- closely related to the squid. The remains are the fossilised skeleton of the ‘rostrum’, the hard part of the tail we can see today.