Island Geology and Fossil Hunting
"No other area of comparable size in England has such a variety of formations in easily accessible exposures and containing such a diversity and abundance of fossils."
(Alan Insole, Brian Daley & Andy Gale. 1998. The Isle of Wight. Geologists' Association Guide No.60. London)
An almost complete succession of rocks from the Early Cretaceous to the upper Palaeogene, a time span of almost 100 million years commencing about 125 million years ago, is exposed on the Isle of Wight together with important but less well known Quaternary deposits which yield plant and animal fossils, and the tools of early Man. The Cretaceous - Palaeogene succession is unrivalled anywhere on the near Continent and the variety of dinosaur and other Cretaceous vertebrate fossils to be found make the Island a place of international importance to palaeontologists.
The Island's beaches are the best places to collect fossils and as many of these are located in the Island's Areas of Outstanding Natural Beauty fossil collecting here is a special and enjoyable experience at any time of year . What's more, the cliffs are constantly subject to erosion by wind and waves so there is always something new to find. However, due account must be taken of the tides and weather to ensure that you are not cut off or swept out to sea and it is important that nothing is done which might damage the Island's geological and palaeontological heritage. So, be safe and follow the Geologists' Association's Geological Fieldwork Code.
What's to be found?
Dinosaurs are, of course, the Island's most famous fossils with more than twenty species having been found so far and new discoveries coming to light all the time. Recently, the most exciting discoveries have been the bones and teeth of large and previously unknown carnivorous dinosaurs. Neovenator described in scientific papers in 1996 and in 2001 and Eotyrannus, the earliest relative of Tyrannosaurus so far discovered, described in 2001, are represented by partial skeletons. The very latest discovery was made in 2003 when teeth belonging to a large and more fearsome relative of the already scary Velociraptor, made famous in the kitchen scene from the film "Jurassic Park", were found and identified by Isle of Wight resident and research palaeontologist Steve Sweetman. The best of what has been found, including the new teeth, is on display at Dinosaur Isle at Sandown. Dinosaur Farm Museum near Brighstone also has good displays of local dinosaur fossils and there is an interesting display, including a Polacanthus skeleton at the Fossil Shop at Blackgang Chine. Dinosaur Isle, Dinosaur Farm Museum and the Fossil Shop all operate group tours of the easily accessible dinosaur localities and Steve Sweetman provides more comprehensive tours of dinosaur and other fossil localities for individuals and single family groups, particularly those with more than a casual interest in fossils or with existing specialist knowledge.
Dinosaurs, exciting as they are, make up but a tiny proportion of the Island's fossil record. In the same rocks in which the dinosaurs are found crocodiles and fish are common although these are usually represented by isolated teeth, bones, scutes and scales. In strata overlying those in which most of the dinosaurs have been found the remains of pterosaurs occasionally come to light. Above these the sea flooded the land and fossils of sea creatures are common including ammonites, 'lobsters', bivalves, brachaeopods, sea-snails, sea urchins and the teeth of sharks. These strata, which were laid down in the Middle and Upper Cretaceous, comprise muds and sands, and the Chalk which now forms the spine of the Island culminating in the impressive white cliffs below Culver Down in the east and in the famous Needles rocks in the west. Each rock type represents a different environment and each environment favoured a different community of animals and plants and it is this which accounts for the great diversity of fossils to be found.
At the end of the Cretaceous, as everyone knows, the dinosaurs and many other animals became extinct. This time on the Isle of Wight was marked by a period when the Chalk was uplifted and eroded before sinking to or below sea level again and it is indeed fortunate for the fossil collector that this was so because the sequence of rocks which follow the Chalk are also an extremely rich source of fossils. At times the sea inundated the land and marine fossils can be found. At other times the rocks record periods of sedimentation in lagoons, fresh water lakes and terrestrial environments. Mammals had taken over from the dinosaurs as the dominant land animals and their bones and teeth can be found together with bones and other remains of the crocodiles, turtles, fish, snails, etc., with which they lived. In some places beautifully preserved leaves can also be found and in others even the delicate wings and bodies of insects are preserved. Following the time when these fossils were first buried there is a long gap in the rock and fossil record during which time the Cretaceous and Palaeogene strata were folded by forces which further south produced the Alpine mountain range. Then came the Ice Age when sediments were again deposited burying the remains of plants and animals. Most of these including such things as hazel nuts and acorns are familiar today but some, such as bison and mammoths disappeared with the Ice. It was only at this late stage in geological history that the sea finally breached the chalk cliffs connecting what are now the Needles on the Isle of Wight and Old Harry Rocks in Dorset, flooding Poole Bay and separating the Island as we now know it from mainland Britain.
For more information about the Island's geology and fossils visit Dinosaur Isle or for an in depth personal service contact Steve Sweetman who would be happy to guide you to sites of particular interest to you.
