9a. The Trachodon Tooth, 1860
In this article of 1860, Joseph Leidy described in more detail the fossils that he first mentioned in his seminal paper of 1856. He also included large lithograph plates that illustrated all the fossils. In particular, he provided twenty figures of his Trachodon teeth. Apparently many of these are incorrectly identified, but figures 1-3 do indeed show a genuine hadrosaur-like tooth. The name Trachodon means "rough-tooth," and the roughness certainly shows in the figures. The illustration shown here is a greatly enlarged detail of the upper-left of the plate, which contains sixty-one figures in all.
Leidy, Joseph. "Extinct vertebrata from the Judith River and Great Lignite Formations of Nebraska," in: Transactions of the American Philosophical Society, vol. 11 (1860), pp. 139-154. This work is part of our History of Science Collection, but it was NOT included in the original exhibition.