nature
A young student seeks for fossils on the beach near Charmouth in Dorset, a rich hunting-ground
Wildlife of Long Ago
By Mik
e Geo r ge
Mike George is our regular contributor on wildlife and the countryside in France. He is a geologist and naturalist, living in the Jurassic area of the Charente
MOST MONTHS I TELL YOU ABOUT THE ANIMALS AND PLANTS THAT LIVE IN OUR BEAUTIFUL REGIONAL COUNTRYSIDE. SINCE IT IS JANUARY AND VERY LITTLE WILDLIFE IS STIRRING, I THOUGHT I WOULD GO BACK IN TIME AND HAVE A LOOK AT THE CREATURES THAT LIVED HERE MORE THAN 60 MILLION YEARS AGO.
I
n the Jurassic period, and into the Cretaceous, our area was a lagoonal sea, very warm and teeming with life – a bit like the Caribbean today. The water was alive with tiny creatures that scavenged calcium and carbon dioxide out of the seawater to build a tiny skeleton to support their tissues. When they died, they fell to the sea floor where their skeletons coalesced into a limy ooze which eventually hardened to form limestone. So, in essence, limestone is in itself a fossil. But what excites folk is to find traces of larger animals. And there were plenty of those, which also sank at the end of their lives and became a part of the limestone.
36 etcetera
However, it must be said that the preservation of the fossils is not very good except in rare cases, as a lot of recrystallisation has occurred within the rocks, wiping out fine details of the fossils. What can you find?
whole ammonites, which they would sell for a premium, as there was a fashion for incorporating one or more in the walls of stone-built houses as display specimens. If you keep your eyes peeled you may spot examples.
Our area was a lagoonal sea, Occasionally you Ammonites are the most very warm and teeming with may see the traces easily recognised. These life – a bit like the Caribbean of a bullet-shaped relatives of the squid and shell, especially in nautilus lived in coiled, limestone flag-stones. These are the shells ribbed shells. Many were small, but some of belemnites, also relatives of the squid, grew to 40 cm diameter, and some even who strengthened themselves with this larger. Usually, by looking carefully, you internal skeleton. Very occasionally, one will find partial impressions of the shells may find a specimen where the in stones lying in the fields. When the belemnite’s ink-sac has been preserved. limestone was being quarried the quarrymen would sometimes find casts of Some early palaeontologists in the 19th
