Rocks

Take any rock or stone and it has its own story to tell. Rocks range from thousands to billions of years old so their stories can be very long but also incredible.

With careful study a rock can tell you if it’s been melted, shattered, squashed, heated, dissolved, eroded, buried, scraped, rolled, intruded, erupted or even eaten!

The rocks in the cliffs and on the beach at Charmouth are the remains of an ancient Jurassic sea. They are made up of layers of sediment laid down in an ocean around 195 million years ago and contain lots of fossils. The cliffs around Charmouth are part of the Jurassic Coast, England’s first Natural World Heritage site.

Chert

Chert
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Age: Cretaceous - around 100 million years old
Composition: Silica and sand
Origin: Top of the cliffs and river

The most common stone on the beach.

Chert is very hard stone composed of silica. Some chert pebbles are sugary like sand and that’s because chert is formed from sandstone. It is usually a sandy or orange colour. We usually don't find any fossils in these rocks.