Originally, dinosaurs were thought of as either giant, sprawling lizards, or bulky, quadrupedal reptiles with some mammal-like features. But, in 1858, American paleontologist Joseph Leidy (1823–1891) described an almost complete skeleton discovered by W.P. Foulke in Haddonfield, New Jersey. The fossil skeleton, named a Hadrosaurus, was more complete than any yet discovered. It also indicated that the dinosaur was bipedal—a radical notion for its time.