SHARK'S TEETH AND DEVIL'S TOENAILS

October 07, 2014  •  Leave a Comment

IT'S ENJOYABLE TO VISIT a classroom and ask children what they think is the oldest thing around. The answers are usually predictable and occasionally imaginative – the teacher, a local graveyard, a church, someone’s granddad, a nearby castle, will often feature on the list.

After a minute or so of exploring the possibilities, I produce from my briefcase a 40,000-year-old shark’s tooth, its enamel still perfect and as sharp as it was when that creature swam in ancient seas. Sharks, being a perfect killing machine, have hardly changed at all since that tooth was encased in silt and eventually turned to stone. It has not had to evolve all that much, because it has reached what could be argued is evolutionary perfection.

In classroom talks, I soon follow that tooth with a piece of coral from Clew Bay – 250 to 290 million years old and proof that we once had warm seas around Ireland. Eyes light up as the conversion turns to how fossils are formed. The children’s fascination with those ancient lives about which we know so little is encouraged by teachers who appreciate that the past isn’t dead, it’s just waiting to be explored by imaginative young minds.

As I go back in time, with fossils even older than the onealready shown to the class, the sense of wonder amongst the children grows. My favourite fossils are trilobites, ranging in size from a couple of centimetres in length to the largest in my collection, which is 18 centimetres long. These were the most numerous and successful marine creatures on earth some 570 million years ago. Some grew to over three feet. Like most fossils, the trilobites are now extinct.

The timescales involved in fossil collecting is just mind blowing, especially to 12 and 14 year olds who think that someone of 40 or 50 is ‘old.’ For me, there is the humbling knowledge of just how short my life will be in comparison to the age of fossils of once living creatures whose lives were so long ago that I cannot begin to comprehend the distance involved.

Since I began collecting fossils back in the late 1990s, I have built up a small collection that rests on a bookshelf behind where I sit and write each day. I also have a collection of miniature owls (but that's another story). A nice piece of coral (perhaps 270 million years old!) turned up in limestone that once came from an old quarry at Mulberry Lane, just up the road from where I live. Another, a brachiopod from 250 million year ago, is representative of a group of creatures still living in the sea today. That fossil came from limestone taken from a cliff at Maryville in Kilworth.

Curiously, computer technology is helping us to understand and comprehend how creatures from gigantic dinosaurs to tiny trilobites once lived. In extraordinary cases, such as when a beetle or small frog was trapped in tree gum that eventually turned to amber, paleontologists can closely study every detail down to the microscopic facets of an insect’s eyes. Anyone who saw the BBC series, ‘Walking with Dinosaurs,' got a glimpse of how some creatures probably lived and moved long before humans first appeared on the planet. Very many were already extinct by the time we got here.

In the case of dinosaurs and some other creatures, it’s not just their fossilized bones that tell us about how they lived. Much more interesting is their fossilized tracks, eggs and babies. These are found in parts of the world from Montana to Mongolia. Some of the footprints are three feet long and using computer technology, scientists can work out the speed at which those amazing animals travelled.

Trackways are also invaluable. In Colorado, large long-necked dinosaurs walked in groups, keeping their babies in the middle for protection just as many other species of animals do to the present day. We know this only because of the fossilised footprints they left behind.

There was a time when people thought that all these fossils were the remains of animals and plants that perished in the biblical flood. That was nonsense, of course, but people believed it because they had no reason to doubt what was said in the bible. In England, fossils of the bivalve Gryphaea, commonly found in Devon, were though to be devil’s toenails because they resemble cuticles from the hooves of goats. Looking at my ‘Devil’s Toenail’ I can see why beople might have thought that, and wonder how amusing some of our current beliefs about the world will seem to future generations for whom we will be merely insignificant curiosities. But for such things as these fossils I never cease to be fascinated. 


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