Free The Rocks Don't Lie: A Geologist Investigates Noah's Flood by David R. Montgomery Page B

thought that they were petrified lightning strikes. While tongue stones and fossils interested Steno, he loved anatomy lessons involving the dissection of human bodies.
    In 1659 Steno slipped out of Copenhagen, eluding the Swedish troops besieging the city. After a brief stay in Amsterdam, he finished his medical training at the University of Leiden. There his skill as an anatomist led him to the scientific discovery that made him famous. Recreationally dissecting a sheep’s head, he discovered the saliva duct. Until then how saliva got to the mouth was a mystery. He went on to discover tear glands, disproving the conventional wisdom that pain or grief squeezed tears from the brain.
    Following his graduation in the winter of 1665, Steno came to Paris. There, he boldly challenged Descartes’ claim that the tiny pineal gland housed the human soul near the seat of the brain. Steno’s careful dissection of human brains disproved the great philosopher’s assertion that the nut-shaped gland twisted and pulled strings animating the human body. Steno showed that the pineal gland was held fast and could not gyrate. He continued to startle the scientific establishment in Paris when he then contributed significantly to understanding the workings of the human heart.
    Now a scientific sensation, Steno was offered the position of physician to Ferdinand II, Grand Duke of Tuscany. With this came access to the Accademia del Cimento (Academy of Experiment), the first and only formal research lab of its day—founded by students of Galileo and supported by the grand duke’s deep pockets. Steno’s journey to Florence carried him across the Alps and Apennines, where he saw fossils layered in rocks high above sea level, well beyond the reach of even the largest waves. Some rock layers lay flat, others were contorted and lay at steep angles. While the fossils in the hills around Florence looked like seashells, most natural philosophers did not consider them signs of ancient life. The educated consensus was that they were insignificant mineral oddities, sports of nature that merely resembled oysters and clams.
    Soon after Steno arrived, in October 1666, fishermen on the Tuscan coast hauled in the body of a monstrous great white shark near the mouth of the Arno River. When word of the several-ton beast reached the Medici palace, Ferdinand ordered it brought to his court in Florence for the Accademia to examine. But the shark was too large to transport and was already starting to rot. So its enormous head, as big as a whole pig, was loaded onto a horse-drawn cart and sent up the Arno River valley.
    Steno, the academy’s newest member, considered the honor of dissecting the enormous shark’s head a once-in-a-lifetime opportunity. He cut as the grand duke and a mesmerized crowd of courtiers watched. The jaws were large enough to swallow a man whole. Yet its brain was tiny—just three ounces. How could such a diminutive brain control a giant killing machine?
    Steno focused first on its teeth. Each serrated blade was identical to the mysterious tongue stones. They were as identical “as one egg resembles another.” 1 Seeing that tongue stones were actually shark’s teeth, he wondered how the teeth of giant sharks could end up enclosed in solid rock. They must have become fossilized after laying in the mud of an ancient seabed that somehow became stranded high above the sea.
    Steno described his findings in a short report to the grand duke, with a digression on the origin of tongue stones and the implications for understanding other fossils. He pointed out the flaw in the conventional wisdom of the time: that fossils spontaneously grew within rocks. A growing object would crack the rock, yet one never saw cracks around fossils found in rocks. Even more telling was that tongue stones were always perfect replicas of their biological counterparts. In contrast, most crystals contained a defect, even when grown in a lab. Steno argued that fossils