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About the Dinosaur Coast

World Class Geology in North-East Yorkshire

The Cretaceous Chalk cliffs at BemptonNorth and East Yorkshire have some of the best Jurassic and Cretaceous geology in the world. Erosion of the massive cliffs reveals an array of spectacular fossils. The deep valleys formed during the last Ice Age give many inland exposures and spectacular beauty spots. The wide range of fossils provides evidence for the changing environment of tropical seas, rivers and swamps in the region’s ancient past.

The last Ice Age (over 10 000 years ago)

A mammoth tooth from near Scarborough During the last Ice Age the North Sea was covered by ice (often hundreds of metres thick), leaving much of Yorkshire as a frozen wasteland. Many creatures thrived in these harsh conditions, living off the stunted vegetation and preying on other animals. The evidence for this period of change is mostly seen in the carved landscape, but also in extensive deposits of boulder clay and other glacial debris.

 Where can I find this geology? 

The Holbeck Hall landslip The Upper Jurassic limestones in Forge Valley

The boulder clay dumped by the retreating ice can be seen mostly between Scarborough and the River Humber, but good examples are at Filey Brigg and Holbeck Hall landslip (on the south side of Scarborough) where the unstable boulder clay has slipped into the sea.

Numerous erratic boulders litter the landscape, giving a glimpse of the massive power of the ice. These boulders, which are often very large, have been brought in the ice from as far a field as Scotland, the Lake District and even Scandinavia. They were then dumped when the ice melted. A large example can be seen near the entrance to Seamer station, near Scarborough, smaller examples litter the coast and are easily picked out at places such as Robin Hood’s Bay.

The Cretaceous (about 65 to 135 million years ago)

A Cretaceous sea urchinDuring the Cretaceous millions of micro-organisms swarmed in the warm sub-tropical seas. They died and gradually sank to the sea floor, creating the chalk that now forms the towering cliffs at Flamborough Head. The seafloor was covered in abundant life, ranging from sea urchins (echinoids) to corals, whilst sharks and marine reptiles swam above. The soft white chalk forms towering white cliffs and rolling countryside.

 

 Where can I find this geology? 

The Cretaceous Chalk at Flamborough HeadThe best place to see the chalk in East Yorkshire is Flamborough Head and Bempton (there are no exposures in North Yorkshire). Here, the chalk forms towering cliffs several hundred metres high and is eroded into sea stacks and arches. Inland, the soft rocks are quickly covered by vegetation, forming the low rolling countryside of the Yorkshire Wolds, around Bridlington and Driffield.  

The Upper Jurassic (about 135 to 152 million years ago)

Ammonites and belemnites from the Hackness RockDuring the Upper Jurassic Yorkshire was covered by warm shallow seas. Many large marine reptiles, such as Plesiosaurs swam through the water above a seabed rich in animal life. Corals, sea snails and shellfish covered the sea floor, whilst a rich community of ammonites, belemnites and other animals swam above.

The Upper Jurassic rocks are mostly limestones and sandstones. These come in a rich creamy colour, which can be seen in many of the North Yorkshire towns and villages such as Ayton, Helmsley and Pickering. Particularly distinctive are the oolite rocks that are made up of many millions of tiny bead shaped grains of limestone.

 

Where can I find this geology?

The Upper Jurassic cliffs at Cayton BayA fossilized Ginkgo leafThis geology forms the distinctive Tabular Hills inland from Scarborough and Whitby. The hills are flat topped and have very steep sides where the hard rocks such as the Lower Calcareous Grit, come to the surface. Particularly good exposures can be seen in Forge Valley, at Cayton Bay and at Castle Headland, Scarborough.

The Middle Jurassic (about 152 to 180 million years ago)

The Middle Jurassic was dominated by ever changing river channels that snaked across the landscape, occasionally flooding to bury the plant and animal life. Lush sub-tropical vegetation flanked the rivers and numerous dinosaurs roamed the banks feeding on the plants and stalking prey.

The Middle Jurassic rocks are dominated by sandstones, often showing well developed cross-bedding. These rocks contain casts of dinosaur footprints, but few delicate fossils. Thinner deposits of mudstone contain several plant beds, which preserve leaves, seeds and flowers in amazing detail. 

Where can I find this geology?

The Middle Jurassic cliffs near Ravenscar

The Middle Jurassic cliffs near Ravenscar

One of the best places to find this geology is on the coast, between Scalby Mills and Ravenscar and at Whitby. Here the cliffs are made up of massive sandstones, sometimes containing dinosaur footprints. Inland, the Middle Jurassic rocks can be found under much of the heather moorland.

The Lower Jurassic (about 180 to 205 million years ago)

Lias ammonite

A Lower Jurassic ammonite

These rocks form dark coloured shales and limestones, they are often quite soft and preserve very fine details of the fossils. They tend to form towering cliffs, which are slowly eroded away by the North Sea.

Where can I find this geology?

Some of the best places to see these rocks are around Whitby and Robin Hood’s Bay. The large quarries at Ravenscar are an excellent place to visit the remains of the alum industry that exploited these rocks.

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