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Solnhofen: A Jurassic journey

A dragonfly flitted across the water, subtropical sun glinting on lacy wings. Unwisely, it landed on the chalky white mud of Jurassic Germany 280 million years ago, and got stuck. The jewel-like wings could not lift the dragonfly out of the soupy muck. It was held fast.

Time slowly did the rest, changing the beautiful creature into a stone, as if Medusa herself had been there to cast a baleful glare.

Solnhofen, the world-famous quarry in southern Germany that once fed the cultural appetites of Roman nobility, had no limestone as yet, nor even a name. It was a stagnant back reef basin filling up with white mud, a place where death was a rule and life an exception.

An unyielding sun cooked the waters, evaporating them down to salty, sticky mud that could trap unwary creatures like the 5- to 6-inch dragonfly. It would lie there dying, baking in the sun, slowly covered by white carbonaceous sediments that preserved the insect in almost perfect detail.

A set of unusual circumstances made such fossils possible in the white Jurassic stones of Solnhofen.

The shallow, inhospitable lagoons were protected from the main force of the Tethys Seas by a C-shaped continent known as Pangea. It included North America and Europe at the top, Africa and South America on the left and Australia and Antarctica on the bottom.

Pangea was already beginning to creep apart by the time of the Jurassic. Geologic forces ground tectonic plates against each other and opened up rifts that were changing the shape of land masses.

A rift beginning in the Australian plate spread inexorably northeast and was rotating Africa around. India was pushed outward, to the east end of the Tethys Ocean. The Tethys sea shrank as the land masses that would one day be called Africa, Europe and Saudi Arabia closed in.

These changes would have been all but imperceptible to the creatures of the time, but they were unstoppable and put pressure on the environment and the creatures living therein.

The “open” side of these shallow, brackish lagoons were protected by coral reefs. Otherwise the massive waves of the Tethys Sea, the ancient ancestor of the Black, Caspian and Aral seas, would have destroyed the specimens that were slowly but surely being imprinted and preserved in the white silt and sediment.

Violent tropical storms, flash floods and mudslides fed the brackish graveyard from time to time with more of the extremely fine sediments that hung like a haze in the water. This settled on the dead and dying creatures that sank to its bottom. Everything that arrived in the salty backwater was most likely dead on arrival — or nearly so — but even the living could not survive for long.

Evaporation left Solnhofen too salty to support marine life, and, with plants few and far between, the water lacked oxygen at its lower levels. Not even the microbes that typically speed decomposition found a niche here, nor any scavengers who would have disturbed the remains.

That left the dead and dying creatures still as stone in placid waters, where fine white mud drifted over them like a filmy veil. So fine, so still, even the final death tracks of Solnhofen’s victims have been preserved.

That veil of time laid down 280 million years ago has been lifted slowly through centuries of quarrying.

A horseshoe crab in the center of a death spiral are among the treasures hidden here, as well as dragonflies complete with fragile wings, archaeopteryx with a clear impression of feathers, soft-bodied jelly fish and sponges. These would all normally be too delicate for the rigors of fossilization. But the conditions that made the Solnhofen quarries so inhospitable to life made them nearly perfect for the preservation of rare fossils.

More than 450 species stumbled or were dropped into this sub-tropical graveyard by storms, floods, mudslides or bad luck, and have thus been preserved for all time. Shark-like icthyosaurs, smallish crocodiles, sea turtles, jellyfish, squids and starfish, floating sea lilies, dragonflies, wasps, horseshoe crabs, shrimps and lobsters, and more.

The record includes 29 species of the winged lizards known as pterosaurs, complete in some cases down to the fibrous membranes that strengthened their wings. The specimens range in size from two inches — the size of a small sparrow — to four feet.

Pterorsaurs have been a specialty for Allan Smith, a Farmington sculptor who has been using the fossil record and scientific research of paleontologists to make life-size models of dinosaurs and other creatures of ages past.

Only one of the specimens from Solnhofen is an actual dinosaur, and Smith has completed a lifelike model of it. His replica of Compsognathus looks like a snake attached to the body of a miniature tyrannosaurus rex.

Many people think of dinosaurs as giants, but the record at Solnhofen shows that the creatures were more diverse. Just as the creatures of today range in size from the very tiny to the very large, so did the lost denizens of the Jurassic.

At least two compsognathus dinosaurs found their way into the Solnhofen lagoon, though there may be others awaiting discovery. One of the creatures had just eaten a small lizard right before dying. That lost soul drifted to the bottom of the lagoon, its meal intact — and a place in history forever assured.

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