The earlier groups of Beaked Dinosaurs are found in both Europe and America, and in the Cretacic the Duck-billed and Armored groups are represented in both regions. The Horned Dinosaurs, however, are known with certainty only from North America.
While most of the important fossil specimens in this country have been found in the West, more fragmentary remains have been found on the Atlantic sea-board, and it is probable that they ranged all over the intervening region, wherever they found an environment suited to their particular needs.
The visitor who is introduced to the dinosaurs through the medium of books and pictures or of the skeletons exhibited in the great museums, finds it hard--well nigh impossible--to realize their existence. However willing he may be to accept on faith the reconstructions of the skeletons, the restorations of the animals and their supposed environment, it yet remains to him somewhat of a fairy-tale, a fanciful imaginative world peopled with ogres and dragons and belonging to the unreal "once upon a time" which has no connection with the ever present workaday world in which we live. Birds and squirrels, rabbits and foxes belong to this real world because he has seen them in his walks through the woods; even elephants and rhinoceroses, though his acquaintance be limited to menagerie specimens, seem fairly real--although one recalls the farmer's comment on first seeing a giraffe in the Zoological park: "There aint no sich animal." But dinosaurs--one easily realizes the state of mind that prompts the inquiry so often made by visitors to the Dinosaur Hall:--"they make these out of plaster, don't they?" So far as is consistent with good taste, the aim of the American Museum has been to enable the visitor to see for himself how much of plaster reconstruction there is to each skeleton, and to explain in the labels what the basis was for the reconstructed parts.