The Cretaceous Chalk
Cliffs at Bempton
Scarborough Museums and Gallery has one of the foremost collections of Jurassic geology on the Yorkshire Coast. With over 5500 fossils and 3000 minerals, the strengths of the collection include: numerous type specimens, which were the first of their kind ever to be described and one finest collections of Middle Jurassic fossil plants in the country. The collection also includes a large selection of Cretaceous fossils from the Speeton Clay and the Chalk, a wide variety of Upper and Lower Jurassic specimens, specimens from the Ice Age such as mammoth teeth and fossils from the Kirkdale Cave and a pristine Carboniferous plant collection. Currently, the collection is being catalogued and conserved in preparation for redisplay in the Rotunda Museum.
Working on the collections at
Scarborough Museum
Spectacular specimens have been chosen from the collection to go on temporary display in Wood End Museum and on the Dinosaur Coast website. The Dinosaur Coast stretches from Redcar to Flamborough. This gives a taste of the quality and range of our fossils and minerals that due to limited exhibition space, are often in storage.
Geology sites
This area is very important for looking at geology because there is so much to see compared to other places. The rugged coastline provides slices through the rocks that are often more than a hundred metres thick and are much more complete and extensive than elsewhere. This means it is easy to see how the fossils change as the rocks get older or younger. In the rest of the UK, the same rocks are usually hidden deep beneath the ground. Smaller exposures complete the picture inland. Clues to the more recent geological past are seen in the spectacular landscape of valleys and hills formed in the Last Ice Age.
The Upper Jurassic limestones
in Forge Valley
The last Ice Age (over 10 000 years ago)
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.
The collection provides evidence of the wide range of the animals that roamed this harsh environment. Specimens include massive mammoth teeth and Hyena bones.
A mammoth tooth from
near Scarborough
There are many examples in North and East Yorkshire of how the landscape that has been altered during the Last Ice Age. Spectacular valleys such as Newton Dale and Forge Valley cut through the landscape. These were formed when glacial lakes dammed by the ice, escaped through geological weak points to release massive torrents.
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.
The Holbeck Hall
landslip
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)
During 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.
A Cretaceous sea urchin
The collection includes some fantastic examples of sponges, echinoids, sharks teeth, lobsters and ammonites, often preserved in spectacular detail.
The 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)
The Cretaceous Chalk at
Flamborough Head
During 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.
The collection illustrates this rich environment with spectacular fossils such as ammonites, echinoids, starfish, bivalves and corals.
Ammonites and belemnites from
the Hackness Roc
This 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 Upper Jurassic
cliffs at Cayton Bay
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.
The spectacular plants from this period are one of the stars of the collection. Slabs full of Ginko leaves, ferns and cycads, are complimented by a range of dinosaur footprints and spectacular bones. These fossils make the collection one of the most important of its type in the country.
A fossil Ginkgo
leaf
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 Middle Jurassic
cliffs near Ravenscar
The Lower Jurassic (about 180 to 205 million years ago)
The Lower Jurassic was covered by a warm moderately deep sea. Large marine reptiles, such as Plesiosaurs and Ichthyosaurs glided through water chasing prey such as ammonites and belemnites. The rich sea-floor life included crinoids and shellfish.
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.
The Lower Jurassic collection includes some of the best-preserved ammonites, belemnites, fish and marine reptile bones from the area. Unusual specimens such as lobsters and echinoids are also represented.
A Lower Jurassic ammonite
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.
The Lower Jurassic rocks
at Robin Hood’s Bay