University of Vermont

Evolution 101


Nicholas Steno

Nicholas Steno   
Niels Stenson (Nicholas Steno) was a Danish anatomist responsible for developing a fundamental geologic theory with his "dissertationis prodromus" in 1669. In this work he outlined three of the defining principles of the science of stratigraphy: the law of superposition, the law of original horizontality and the law of lateral continuity.  Steno became interested in the study of rock layers (stratigraphy) by chance, when a local duke ordered him to dissect a large shark local fisherman caught off the coast of Livorno, Italy.  Steno noted that the shark's teeth resembled certain stony objects found within rock formations, which were referred to at the time as "tongue stones" or glossopetrae.  Steno was the first to put forth the idea that these glossopetrae were in fact altered teeth that had belonged to ancient sharks that were buried in the mud long ago.  This idea ran contrary to the common belief that fossils "grew" inside of rock outcrops, but echoed ideas of contemporary geologists Robert Hook and John Ray.  Steno's work on shark teeth led him to the question of how solid objects could come to be found inside another solid object, thus feeding his interest in stratigraphy and sedimentology.  His observations contributed to the fundamental observations that bind together the study of geology, which over time provided the framework that would allow fellow scientists to use fossil evidence to examine how life evolved on Earth.

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Last modified October 06 2008 01:58 PM

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