An Upper Triassic Ramble - Saint-Nicolas-de-Port rubbish tip 215 million years ago

by Trevor Dykes

For man who isn't a palaeontologist, Trevor Dykes knows a lot about the subject. But his other interests are humour and making science fun, so you probably haven't seen anything like this before.

Interesting Rubbish

Saint-Nicolas-de-Port in northeastern France is a small town with a remarkable rubbish tip. In general, rubbish tips get a poor press, but they do have their grateful fans. A large specimen in Bochum, Germany is frequented in the summer by a man dressed in rags adorned with litter. Sometimes, he buries himself in the garbage, leaps out and grabs startled passers-by. Everybody needs a hobby, and he works at various jobs during the rest of the year to pay for this pleasure. Before anybody phones the police, I should point out he’s an ornithologist and the surprised pedestrians are feathered. Although not everybody’s cup of tea, this activity has enabled him to amass an impressive database recording where these birds have flown in from. (They’re generally wearing rings and a surprising number pop down from Scandinavia.) As well as indulging his interest, this effort is scientific fieldwork.

Many archaeologists and historians have fed their knowledge from rubbish tips as well. If you want to find out about available foodstuffs on a Polynesian island a thousand years ago, then garbage is the stuff to look for. (Some journalists have developed a similar approach to investigating the private lives of rock stars.) Sometimes, a comparison of tips from different ages can provide evidence on changes in the flora and fauna. The remains of giant moas don’t turn up in Moari rubbish beyond about 600 years ago, whereas their bones suggest these three-and-a-half metre big birds kindly supplied a third of the nutritional requirements in earlier centuries. Their absence in later kitchen refuge reflects very bad news for giant moas. They’d gone extinct, as they weren’t terribly good at hiding.

Natural junk

Rubbish isn’t a human invention. The White Cliffs of Dover are mainly composed of countless mini shells, which are no longer required by their long dead manufacturers. As the area was then covered by a shallow, warm sea the deposits built up pretty much in situ. A similar deposition of chalk is presently underway in the Caribbean.

Blind librarians are at work archiving natural rubbish. Rivers carry large volumes of litter to the sea, while dropping off heavier material at convenient locations along the way. Tides may then take over responsibility for further sorting and distribution. Where the waste ends up is determined by size, density and prevailing currents. These utterly brainless forces can be very diligent archivists, and heaps of naturally sorted debris can also provide fascinating information.

This brings us back to Saint-Nicolas-de-Port. Although the modern rubbish tip in what used to be a quarry may have its admirers, my interest centres on the older trash below it. The rock contains a layer varying in thickness from a mere twenty centimetres to a modest metre. This was archived many years ago by natural blind librarians, and long thrown out junk provides an intriguing glimpse into the lives of dead residents from a neighbouring area. Some of the remains can’t have been originally discarded here, because the place was under water at the time. The same applied to much of Europe. In this case, ‘many years’ refers to about 215 million of them. This was towards the end of the Triassic. Europe was an archipelago of islands peering out of a shallow sea.

This thin layer is what’s technically known as a bonebed, although (certainly with regards to the remains of landlubbers), toothbed would be apter. It must’ve been close to land and may have been part of a river delta.

Of fossils and fossilers

When the mind turns to Mesozoic landlubbers, images of huge, terrifying dinosaurs tend to ring the bells and turn on the lights, and remains of relatively early representatives have been found here. Pterosaurs may be in flight in the background of the mind’s eye, and they’ve also been recovered. However, Mesozoic wildlife was much more varied than the narrow cast list of dino movies might suggest. Most terrestrial vertebrates (land animals with backbones) were tiddlers. As their fossils also turned up, this is a microvertebrate site.

According to Hollywood, fossiling is typically conducted by paleontologists of vigour and beauty, so the movies are partly accurate. They descend upon some God forsaken wilderness, and the air is electric with sex appeal and carnal longing. Again, this reflects reality. It’s during the scene in which the lead characters are finally overwhelmed by their primeval urges, that fantasy takes over. They tear off their clothes and begin making passionate love by a conveniently exposed, complete specimen of a twenty foot Tearyourheadoffsaurus. The presence of such a skeleton is highly unlikely. Saint-Nicolas-de-Port hasn’t provided any.

What it has yielded is an insight into an ancient, diverse ecosystem. The variety may have been enhanced somewhat by the presence of an archipelago, as even relatively close lying islands can provide homes for different species, as Darwin noticed in the Galapagos Islands. I’m most concerned with one particular group of vertebrates. For the moment all that’s relevant is their size; small or smaller. To emphasize this, I’m going to mention the extreme case; a fossil with a length of less than half-a-centimetre. It’s quite amazing that such a slither should attract anybody’s attention in a quarry. Of course, a better understanding is gained when the more typical size spectrum is introduced. It’s between one and two millimetres. To add to the fun, these miniscule fossils have been found only in isolation among sand and other sediment, and they’re rarities. To offer a comparison, I’ve just spilt some black peppercorns on the kitchen floor, and hope nobody goes in there before my wife gets home. They have a diameter of three to four millimetres, and are thus three times larger than most of those fossils. This raises a good question.

How on Earth does anyone find stuff that small in a quarry?

I maintain looking for a needle in a haystack (on a concrete floor) would be easier. Paleontologists are resourceful people, and habitually select efficient methods. Doing things the complicated way is evidence of stupidity. For the haystack challenge, a paleontologist might employ a supply of petrol bombs, a discrete distance and a metal detector. You’d probably be able to get on with your sewing within a few hours.

(I’ve had the pleasure to correspond with a paleontologist who has employed dynamite to find fossils; excavated below sea level in a cove; persuaded Cadburys to donate and deliver a cubic metre of chocolate by helicopter; and charmed an Australian airline into lending a passenger plane, so as to give his new friend, Qaantassaurus, a joy ride around the continent. I’m confident he’d find the needle more quickly than most.)

In order to find really small and rare fossils, you must first discover where to look and then search very thoroughly indeed. Before the modern rubbish arrived, that’s what happened with that thin rock layer at Saint-Nicolas-de-Port. Several tons of sediment were laboriously excavated. They were then methodically sorted by whatever means were available, (sieves, lots of water and floatation in chemicals are among the usual techniques), in order to isolate material of the correct ranges of density and size. Anything which met those qualifications was then eye-strainingly examined. Finally, the fossils were safely catalogued, stored and, eventually, meticulously described. Work like this stretches out over decades.

So here's a taste....

Taking a Triassic stroll
Ladies and gentlemen, I thank you for your attention. As we’re now appropriately equipped with some background information, the time has come for us to leave the craft and commence our short ramble. I’m sorry the few hours available might not obviously be reflected in the prices we’re forced to charge for this tour, but travelling back to the Upper Triassic is ruinously expensive. You can all count yourselves lucky for being able to afford it. Please feel free to ignore any instructions I may give, but do so at your own risk. Should you happen to get lost, then you probably won’t have too many difficulties to face, as there’s little likelihood of you surviving for very long. This would be a good time to remove your shoes and socks and roll up your trousers. The water’s both shallow and reasonably warm. Read the whole story

Back to All Articles Index