Jurassic
Coast:
|
|
|
Ammonites
are the most popular type of fossil found there and resemble coiled
snakes; they are also known as 'snakestones'; they can be found along
the whole length of coast from Staithes to Scarborough; when alive an
ammonite resembled the modern day pearly nautilus, rather like a squid
in a shell; the creature only lived in approximately a third of the
outer portion of the shell, the rest of the shell being made up of gas
filled chambers that acted as bouyancy aids to enable the ammonite to
swim without sinking. In the Whitby area ammonites are generally preserved in three ways, they will either be found squashed very flat on the surface of shale, preserved more or less intact inside an ironstone nodule, or preserved in mudstone, usually with the outer whorl intact but the centre squashed; local legend says that the ammonites were formed when the Abbess of Whitby, later St. Hilda, drove a plague of snakes over the cliff at Whitby; the species of ammonite pictured was named Hildoceras in honour of this mythical feat. |
![]() |
Belemnites, also known as 'Devils Thunderbolts' look a bit like bullets; the nearest modern equivalent for the part most commonly found is a cuttlefish bone, often found in Budgie's cages; as with ammonites, the belemnite was a squid like creature but instead of having the ammonite's external shell the hard structure of a belemnite was on the inside; this internal shell is known as the guard. They vary in size and shape, from long thin ones 'Cuspiteuthis tubularis', which can be found on the surface of the shale near to Black Nab in Saltwick Bay, to 'Phragmocones'; the extension to the guard in a belemnite is known as the phragmocone; and because the phragmocone was more delicate than the guard they are more difficult to find, as they are unlikely to have been preserved intact; occasionally though they will be preserved inside an ironstone nodule and more rarely in shale. |
![]() |
Dinosaur Footprints: Footprints are known as 'trace fossils' and are good evidence that dinosaurs once roamed this area at around 160 million years ago, when the area around Whitby was a huge river delta; there were large mudflats there, which dinosaurs walked through leaving footprints; some of this mud dried quickly in the tropical heat capturing the footprints; over time these would have become covered with something like sand; the sand and mud layer then became further buried by even more layers of sand, silt and mud and over time they changed into sandstone and mudstone. The footprints we find nowadays are actually 3D sandstone casts of the original footprints; the best place to look for dinosaur footprints is Burniston Bay near Scarborough; follow the steps down to the beach and then turn left, the large sandstone blocks at the base of the small cliff sometimes have three toed footprints on the surface; the footprint bed is the layer of sandstone about 3 to 4 metres up the cliff face from which these blocks have fallen; although Burniston Bay is the easiest place to find the footprints, they can be found all along the coast from Scarborough to Whitby. |
![]() |
Marine Reptiles: During the Jurassic period the seas in this part of the world were the home of ichthyosaurs and plesiosaurs; both measured from 3 to 13 metres in length; the ichthyosaur resembled a dolphin in appearance and is thought to have been a fast and powerful swimmer; the ichthyosaur was the only marine reptile known to give birth to live young; the plesiosaur had a very long neck and used four paddle like fins for propulsion; in contrast to the ichthyosaur, the plesiosaur would leave the water to lay eggs on the land; it is thought that if the Loch Ness Monster exists it is probably a descendent of the plesiosaur; both reptiles were air breathers and would have to surface regularly for air. Although fossilised remains of reptiles are uncommon they can be found in this area; vertebrae are the most common parts to be found, usually on the seashore and look like discs with concave sides ranging from 1cm to 30cm in diameter; complete skeletons are still occasionally found in the cliffs but are extremely difficult to remove intact. |
![]() |
Bivalves: Cockles, mussels and oysters are all bivalves; the only difference is that some of the shellfish you find on the Yorkshire Coast are 150 to 190 million years old; when shellfish died most of the shells became filled with mud or silt, this provided a solid core for the shell as it became fossilised; as the shell was made of a substance similar to the fossilising minerals quite often parts of the shell remain intact and the original colours are visible. |
![]() |
Crinoids: Amongst the shingle on the beach you may find very small fossils which resemble starfish, they are part of a crinoid, a creature which is related to the starfish; crinoid can be described as rather like a starfish on a stem; the stem would be made up of hundreds of these flat star shaped plates, called ossicles, stacked one on top of the other; at the top of the stem would be the head 'calyx' with 5 or more arms which were used to catch food and at the bottom of the stem a 'root' system to hold the creature down; although crinoids look like plants and have the nickname 'sea lillies' they are not plants. |
![]() |
Scaphopods: Scaphopods are shellfish which first put in an appearance in Devonian times, about 417 to 354 Million Years Ago, and have hardly changed since; they can still be found in warmer climates and are known as 'tusk shells' because of their similarity in appearance to elephant's tusks; in life a scaphopod lives buried in sand with just the thin end of the shell protruding into the water and the head end, called the foot, at the lower end. |
![]() |
Plant Remains: Plant remains are quite common in the Whitby and Scarborough areas; leaves are usually preserved as carbon impressions of the original leaf; tree trunks and branches are sometimes preserved as flattened coal like bands, sometimes as mineralised casts and occasionally as Jet. |
![]() |
|
|
|
|
|
|