Sharks!

Sharks Teeth fossils Herne BayMost local people know that many fossils, including fossilised shark's teeth, can be found along the foreshore between Beltinge and Reculver but few might realise that the area is internationally regarded amongst fossil hunters world-wide with many travelling to the area just to hunt for shark's teeth along our beach, on our doorstep, and it's probably a surprise to many that once upon a time the waters around what is now the North Kent coast teamed with sharks - most commonly the Sand Tiger Shark although examples of Bull shark and Mako teeth have been discovered along our shoreline.

Unlike humans, sharks teeth are not attached to the gums on roots and sharks routinely lose and re-grow teeth. On average, a shark will lose at least one tooth a week and another can replace it within a day!  Typically sharks average out to 15 rows of teeth in each jaw. Although most have 5 and then there is the bull shark that has 50 rows of teeth. Sharks lose their teeth because they may become stuck in prey or broken and forced out and then, of course, there are teeth from dead sharks.

Read more about sharks and their evolution at The National History Museum

Most of the fossilised shark's teeth we find along our coast date from around 56-54 million years ago but quite how our coastline looked, or indeed if we had a coastline at all is hotly debated amongst experts.  Certainly sea levels varied enormously over millions of years with the melting and subsequent re-freezing of the ice caps and with volcanic action undersea and on land.  The fossilised shark's teeth we see today were most likely deposited at a time when sea levels were high and what is now Southern England was largely underwater then, as the seas receded and sea-bed became land, the fossils were increasingly covered over by silt and soil to be preserved in their fossilised form and there they would have remained for many millions of years.

doggerland2Step forward then to only a mere 6 or 7 thousand years ago and, as you will see from the map below, much of what is now the North Sea and English Channel was habitable land with many rivers, lakes and rich, lush vegetation which supported a diverse variety or plants and animals.  In recent years fishing trawlers have brought to the surface in their nets the remains of lions, mammoths and pre-historic, man-made tools from the sea bed.  It was then probably around 5,000 years ago that the seal levels began rising once more and Doggerland vanished beneath the waves and our coastline started to take shape, much as it is now.  There is speculation that a massive tsunami caused by volcanic eruption close to Iceland (the country, not the shop) caused huge waves to sweep across Doggerland via the Norwegian trench and, although this is speculation, would explain how Doggerland appeared to vanish so quickly.

Today, the only remnants of Doggerland which are sometimes visible above the sea is the sandbanks we call Dogger bank (between Kent and Holland) and the areas of moving sands off of East Kent called the Goodwin sands.

As the sea reclaimed the land, soil and deposits have been washed away over thousands of years to reveal the fossilised remains of the shark's teeth that we find today and this process continues with each and every tide where more sea bed is eroded, revealing yet more fossils.

 

Time Team Special - Britain's Stone Age Tsunami

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