Brontosaurus Under Construction Final skin of fiberglass completes the replica of the 20-ton brontosaurus. Nine reptiles were recreated for the Sinclair Refining Company's World's Fair exhibit to demonstrate the age and quality of crude oil from which Sinclair's products are refined. Sculptor Louis Paul Jonas created the replica's; they were brought by barge from his Hudson, New York studio to the fair; and are currently touring the country aboard flatbed trailers.