WhenDINOSAURSRoamed Hastings |
|
|---|---|
|
The evidence is cast in stone: dinosaurs once ruled our town! Local historian Ken Brooks gives us a tantalising taster of his guided fossil walks of the local coastline. The walks make a perfect afternoon outing for the whole family. The beach from Rock-a-Nore to Pett Level contains a fascinating variety of rock structures and fossil evidence. Together these provide important clues which enable us to reconstruct the ancient environments of this area. Between 100 and 140 million years ago, during the Lower Cretaceous period, much of southern England was covered by lakes and lagoons. Rivers flowing from the north and west deposited great quantities of sand and silt on extensive flood plains. These sediments later became rocks which are now known as the Ashdown Sandstone and Wadhurst Clay. Molluscs, fish and crocodiles lived in the rivers and lakes while the land was dominated by dinosaurs. Plants such as horse-tails, ferns, cycads, conifers and tree-ferns, indicate that the summers were hot and dry, followed by wet and humid conditions in the winters. Around 100 million years ago a gradual rise in sea level flooded southern England and other areas of the British Isles. For the next 30 million years, the remains of tiny shellfish settled on the seabed to form a vast thickness of calcium carbonate (now seen as the chalk cliffs of Eastbourne and Dover). Meanwhile Africa was moving slowly northwards towards the European continent and, when the two land masses eventually came together, the immense forces involved created folds in the Earth's crust. Mountains were formed in North Africa and Europe while South-east England was forced upwards into a huge dome-shaped structure, now known as the 'Wealden Anticline'. Since then, weathering and erosion over millions of years have removed the overlying chalk rocks in the central Weald to expose the sandstones and clays of the Lower Cretaceous. Today a variety of fossils, including shells, fish scales, teeth, reptile bones and footprints, may be found preserved in these rocks on the beach between Rock-a-Nore and Pett Level. Large three-toed footprints of dinosaurs, such as Iguanodon, may be seen on siltstone bedding planes. Some of the prints can measure up to 60 cm (2 ft) from heel to toe. These dinosaurs might have been walking by a river or lakeside and left their footprints in the mud. This quickly dried out in the hot sun, and water then deposited silt or sand in the hardened impressions, later forming infill casts. Gradually, over millions of years, these sediments turned into rock. Today, footprint impressions or casts may be revealed when the weaker rock layers have been worn away by recent erosion. |
Although the bones and footprints of Iguanodon are the most common dinosaur remains, other very interesting fossils have recently been found in the Hastings area. These include the spines and vertebrae of Polacanthus and a tooth from Baryonyx.
Articulated skeletons are very rare because most animal remains would have been torn apart by scavengers and then perhaps washed into rivers or lakes by rainstorms. The moving water would eventually deposit the bones, scales and teeth some distance apart. If you plan to go on a fossil hunting trip along the beach always set off just after high tide. Please do not look for specimens below vertical cliffs as rock falls occur without warning. The real fascination of fossil hunting is the moment you find a plant, shell or bone which has been hidden in rock for millions of years and which no-one else has ever seen. There is also the possibility that you might discover a new species - which could be named after you! |
|
|
