The very first dinosaur fossil was a thigh bone found in the year 1787 by Dr. Caspar Wistar in the US. The study of Agathaumas fossils gives us an image of the dinosaur and also tells us a lot about the Agathaumas Characteristics.In early 19th Century, fossils found were formally recognized as the dinosaurs. Fossils of Agathaumas include : The fossil remains of Agathaumas were first found in 1872 in southwestern Wyoming . The bones were preserved in sand and clay sediments, packed with fossil sticks and leaves, indicating a heavily forested habitat . Cope later (in 1873) described the skeleton as "the wreck of one of the princes among giants." Later in 1872, Cope published a description and name for the animal, Agathaumas sylvestris , or "marvelous forest-dweller," in reference to its great size and the environment revealed in the same rocks as its bones . Since these were the first ceratopsian remains found, Cope was uncertain as to precisely what sort of dinosaur Agathaumas was (and for a time considered it a hadrosaur ) until O . In an 1889 paper, Cope suggested that Marsh's Ceratopsidae be renamed Agathaumidae, because of the paucity of Ceratops remains .The dinosaurs first came into existence in the Triassic period of the Mesozoic era which was about 248 to 65 million years ago. The time period in which Agathaumas lived is Late Cretaceous and was present 66 million years ago. Agathaumas discovery is credited to Edward Drinker Cope . It was named and described in the year 1872-01-01 (1872).