Leidy, Joseph; Notice of Remains of Extinct Reptiles and Fishes, discovered by D. F. V. Hayden in the Bad Lands of the Judith River, Nebraska Territory. Proc. Acad. Nat. Sci., Phil., 1856. Octavo, pp. 2. & Hayden, F. V & Leidy, Joseph; Extinct Vertebrata from the Judith River and Great Lignite Formations of Nebraska. American Phil. Society, vol. 11, 1859. Quarto, pp. 32, 1 map, 3 plates.

Both are complete and in recent archival folders, very good.

In 1855 Ferdinand Hayden conducted a geological survey along the Judith River in what was then the Nebraska Territory. He discovered large fossil teeth belonging to unknown creatures. Hayden had the specimens delivered to Leidy in Philadelphia. Leidy recognized the teeth as belonging to extinct reptiles and named eight genera, three of which turned out to be dinosaurs: Trachodon, Trodon, and Deinodon. Leidy recognized what he was looking at and understood that one specimen was from a creature similar to the Iguanadon, and commented that the Deinodon teeth resembled those of Megalosaurus. The above works pertain to these specimens. The first work is the first published notice on dinosaur remains discovered in America. Since Leidy was urged to publish the information as quickly as possible the notice in the March 1856 issue of the Proc. of the Academy of Natural Sciences was not illustrated. By far the most important part of the second work is Leidy's description and illustration of the fossils originally provided by Hayden. Leidy considers these to be twelve new extinct species of fishes, saurians, chelonians and mammals. Plate one contains drawings of fossil teeth of what were the first dinosaur remains accurately identified in America. These are the teeth that were sent to Leidy by Hayden and which Leidy originally identified but did not illustrate as dinosaur teeth. The plate is the first to accurately illustrate dinosaur teeth from America.