The limestone and shale ledges on either side of Lyme Regis are regularly exposed by the low tides. An exploration of the rockpools they contain can reveal a wealth of marine life. Discover some of the problems faced by creatures living in the harsh conditions of the rocky shore. Click here for information on our Rockpooling walks.

Eroded Ledges

The cliffs either side of Lyme Regis are an alternating series of limestones and shales that formed in shallow seas during the Jurassic period just over 200 million years ago.

These two rock types are very different to each other, shales are soft and dark, limestones are hard and lighter in colour. These contrasting materials provide a wealth of habitats for marine creatures.

The shales are soft enough to be burrowed into, and naturally erode to provide crevices under the harder limestone.

The limestone provides a solid attachment for limpets and seaweeds and many other organisms. This helps make the rocky shores around Lyme rich in marine life.

The creatures to be found on the beach are not only influenced by the type of rock, they are also controlled by position on the shore.

At the top of the beach the rockpools are exposed to the air for long periods each day. This is a harsh habitat for marine creatures and exposes them to many perils.

Squat LobsterCreatures not in rock pools face being dried out by the sun, but even in rockpools they are not totally safe. The sun heats the rock pools and also evaporates the water making them saltier. Rain and cold weather have the opposite effects. This exposes creatures to a wide range of salinities and temperature variations, lethal to creatures not adapted to these conditions.

When the tide is out animals are at the mercy of gulls and other shoreline scavengers. The Squat lobster in the photo is in a dangerous position as it could easily dry out or be eaten by gulls.

Here are some of the other things you may find looking in the rockpools to be found at either side of the town.