In 1821, British geologists Henry De la Beche and William Conybeare presented a bizarre, previously-unknown fossil creature to their colleagues in the Geological Society of London. They called their monster Plesiosaurus. A paddle-legged marine reptile akin to the recently-discovered, shark-shaped animals known as ichthyosaurs, the new animal was cast as “a link between the Ichthyosaurus and Crocodile” in the “connected chain of organized beings.”

Don’t let the language lead you on. De la Beche and Conybeare were not advocating an evolutionary view. Quite the opposite.  Speculation about the transmutation of species was “absurd and extravagant,” the naturalists said. Instead, the Plesiosaurus testified to a natural