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DINOSAUR ISLAND - Page 1
by Martin Simpson
Where do you find dinosaurs? It depends where you
left them of course, but one of the best places in the world to start
looking is the Isle of Wight. This tiny lozenge-shaped island situated
in the English Channel boasts over a dozen different types of dinosaur.
Someone once asked me why I moved here sixteen years ago and I told
them it was to search for dinosaurs. "Do they still live on the
Isle of Wight then?", they asked. Well, the fact is that dinosaurs
became extinct everywhere 65 million years ago but they left plenty
of bones, teeth, footprints, eggs and droppings for us to find later.
The Isle of Wight is so rich in these fossilized remains that it has
recently earned the nickname of Dinosaur Island.
The Isle of Wight isn't what it used to be. It used to
be a subtropical paradise, but you have to cast your minds back 115
million years. Some people have great difficulty comprehending this
immense period of time, so it may help to imagine 57.5 million years and
double it. At that time the earth was slap bang in the middle of what some
geologists call the 'Age of Reptiles' and the Isle of Wight wasn't an
Island at all. Instead it was part of a larger land mass situated much
closer to the equator and hence it had a correspondingly warmer climate.
The land was infested with the sort of creatures you can only see nowadays
if you are not too fussy about what kind of mushrooms you eat. These
prehistoric monsters were named dinosaurs in 1842 to distinguish them from
other kinds of ancient reptiles which could swim or fly. Although
dinosaurs could do neither of these things they could stand up straight,
which was enough to give them dominance of the terrestrial environment and
a widespread distribution. In other words they were as common as muck, but
the sea was teeming with sea life as well. Countless thousands of squid
-like shellfish called ammonites abounded, so it was just as much the 'Age
of Ammonites' as reptiles. Yet quite inexplicably 65 million years ago the
age of both was suddenly over as many other life forms kicked the
geological bucket. Since then the crust of the earth has continued to
break up into segments known as plates and each plate has moved relative
to the others like the skin on a giant rice pudding. The exact spot which
ended up being the Isle of Wight moved gradually northwards at the rate a
fingernail grows, which doesn't sound very much unless you wait a few tens
of millions of years. Eventually the last Ice Age receded, the sea level
rose and about seven thousand years ago the 'Peninsula of Wight' finally
became detached from mainland Britain to become and Island, an event which
some experts think was masterminded by the Isle of Wight ferry company.
To find your dinosaur you have to look in sedimentary rocks of the
right age and type. For a rock to have any chance of containing something
dinosaur-ish it must not only be the right age (200 - 65 million years
old), but it must also have been laid down in fresh or brackish water.
Dinosaurs did not live in the sea so their corpses are much more likely to
be flushed into rivers or buried in lagoons, the sediments much later
turning into sandstone, shale or clay. This brings us to the Isle of Wight
of today, where a likely layer of freshwater deposits 115 million years
old is exposed along southern coastal cliffs like the jam in the side of a
sponge cake. As far as England goes you can see this 'dinosaur layer' at
ground level on the Isle of Wight. It is hidden to the west, north and
east under thick layers of younger rocks, only peeping through in the odd
quarry or brick pit. The dinosaur layer is actually a series of layers
hundreds of metres thick, only some of which are fossiliferous (or
dinosauriferous). These strata run along the Islands coast for miles and
are best displayed at Brighstone and Brook bays. Despite their great age
most of the rocks have never truly solidified, but remain as a soft blue
clay which the locals call 'blue slipper' on account of it's vulnerability
to the erosive action of the sea. Each winter brings a series of high
spring tides which combine with storm force winds to erode our tiny island
at an alarming rate. Constant cliff falls, mud flows and landslips mean
that the Isle of Wight is disappearing fast in geological terms and will
probably vanish for good in a mere 50 thousand years. All of this will be
disappointing reading for the average Isle of Wight resident but is great
news for the potential fossil collector who can rely on the elements to do
most of the work.
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