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The Seashell on the Mountaintop by Alan Cutler, Dutton/Heinemann, $23.95/£14.99, ISBN 0525947086/0434008575 Reviewed by Roy Herbert

YOU may not have heard of Nicolaus Steno, but he has been called the founder of geology, and The Seashell on the Mountaintop is his astonishing story. He was a Dane, born as Niels Steensen in 1638, who exhibited a unique skill for dissection and anatomical discoveries. Arriving with a respectably Latinised name at the Florentine court of the Medici, he was sent the head of a giant shark caught by Italian fishermen. (Steno’s illustration of this is still a breath catcher.) He realised that the objects known as tongue stones, which were commonly found in local rocks, were in fact fossilised sharks’ teeth.

How could sea animals’ remains be discovered in rocks at high altitudes? Religious authority said that the Earth had been created perfect, and was then only about 6000 years old. Steno’s observations made the Earth millions of years old, and its history one of violent upheaval. Eventually he realised that the rock layers record that history.

Against the odds, Steno avoided conflict with the Church. He gave up science, became a priest, then a bishop, and was beatified in 1988. Cutler does his extraordinary career justice.