Explore our fossils to see what animals lived in our seas around 100 million years ago.
A century of change
Marine and coastal life has changed dramatically over the past century. But how do we know this? And why is this useful to us now? Pieces of this puzzle can be put together through delving into our natural history collections from the past 100 years.
Mr. Booth’s (Sea)birds
Why keep 100 year old seaweed?
A guide to rockpooling in Brighton
Just off the coast of Brighton, tucked away beneath the waves we have a huge variety of marine habitats including hidden chalk cliffs and reefs – with their rich and colourful diversity of life, they are as good as any tropical reef! When the tide is low, Rockpooling gives us a glimpse into this underwater world, and you don’t have to go far from Brighton to explore some of the best ones.

The Undercliff Walk
The closest pools to Brighton city centre are near Brighton Marina along the Undercliff walk. These pools are within the Beachy Head West Marine Conservation Zone (MCZ). Beachy Head West was one of the first MCZs to be established in the country. The chalk reef is among the best examples of marine chalk habitats in the south east, which supports so many species and when revealed, the Rockpools are full of hidden gems.
So…let’s get started!
First things first, check the tide times! Sometimes you only have a small window of time to search the Rockpools, so checking this is key. There have been a couple of times where I’ve made my friends come with me, only to find the tide is in and the rockpools are covered. Don’t make my mistake! Good sites to use are magic seaweed or tidetimes.

Equipment and footwear
Footwear with a good grip is essential – the rocks can get really slippery; wellies or waterproof trail shoes work well, but beach shoes are the best. Don’t forget sunscreen, a hat and take plenty of water to drink – you will be really exposed to the sun on the rocks. The Wildlife Trust’s top tips for rockpooling shows you the basic equipment you need to take with you to safely observe the animals.

ID guides
The Wildlife Trust’s Spotter sheet is a great way to help you identify your finds if you’re a first-timer. As you become more familiar with the species there are some excellent pocket guides out there like Collins Complete Guide to British Coastal Wildlife or The Essential Guide to Rockpooling
Searching for animals
The far end of the beach towards the sea is the best place to start your search as the deeper pools are here. You can then make your way back towards the beach to search the shallower pools. Animals like to keep cool and damp, so searching under rocks and overhangs will give you a better chance of spotting them. Turn rocks and seaweed over slowly and gently, the longer you look, the more chance you will see things. Listen out for the sounds of fish splashing and crabs clicking too.
Protecting wildlife

The animals in rockpools are quite vulnerable so ensure you turn rocks over and put them back as slowly as possible. Check constantly to see if anything has moved under where you are going to put the rock back. If you collect anything in a bucket don’t keep it in there for long as it will get stressed by the temperature. Return everything you find to the pools as close to where you found it as possible.
Always something new!
The best thing about rockpooling is you always spot something new each time you go. Here are some animals I have spotted during my time rockpooling this summer on the Undercliff pools.
Spiny spider crab

Chitons

Cuttlefish eggs

Shore crab

Strawberry anemone

Reporting your finds
Reporting rare finds to wildlife charities can be really important as it helps be build up a more detailed picture of the wildlife that lives in specific habitats. If rare species are found their is a higher likelihood that the areas will be protected in the future. Find out how data reports helped towards creating Marine Conservation Zones here.
You can report your finds to:
Sussex Biodiversity Record Centre
You can find out about the latest interesting reported finds on the glaucus website
Bivalve shells
This gallery displays fossil bivalve shells from our collection. They are from the Lower Cretaceous period and around 85 million years old. Bivalves first appeared in the fossil record around 500 million years ago. They are animals that belong to the mollusc group and have two hinged shells and 15,000 species still live in our seas today including clams, mussels and scallops.
Sea stars, lilies and urchins
Sea stars, sea lilies and sea urchins are all Echinoderms. The name Echinoderm comes from the Greek word meaning ‘spiny skin’. They first appeared in the fossil record in the early Cambrian period around 542-488 million years ago. The fossils in this gallery are between 100 – 85 million years old.
Sussex: an ancient sea bed

How do we know that Sussex was covered by a warm sea? The answer lies in the familiar white cliffs of the South Coast – Beachy Head, The Seven Sisters and Dover. These cliffs are all made of a rather special rock. Chalk.
But what is chalk?
When you hold a small piece of chalk in your hand from a walk along the South Downs, you are holding the remains of millions upon millions of microscopic marine plants called algae.

These marine plants thrived a in a warm sea that was 200 to 300 metres deep and covered the whole of the South Downs and most of the UK. The only part of the UK you would have been able to see 100 millions years ago would have been the highest peaks of the Scottish mountain range.
The cell walls of these plants were strengthened with a skeleton made of hard plates of calcium carbonate which, after the death of the algae, slowly sank and built up on the sea floor. Layers upon layers of these skeletons built up to form what is now the South Downs and the famous chalk cliffs.
Discover the animals that lived in the seas 100 million years ago in our fossil galleries.
Unique chalk habitats
The chalk has created rare habitats including chalk reefs which are home to an abundance of wildlife.T he Beachy Head West Marine Conservation Zone, which runs from Brighton Marina to Beachy Head, is a wonderful chalk reef. It is home to threatened species including blue mussel beds and short-snouted seahorses. Read our Rockpooling guide to find out more about what you can spot in Beachy Head West rockpools.
chalk reef film from Sussex Wildlife Trust on Vimeo.