What did Robert Plot discover in 1677?

The first scientific account about a dinosaur fossil was not published until 1677 in Europe. Then, Englishman Robert Plot described the lower end of a thighbone that formed the knee of Megalosaurus, a carnivorous dinosaur common in Jurassic rocks there, which walked on its two hind legs. At the time, however, Plot did not recognize his find as the bone of a long-dead reptile.