Dinosaur size
There were larger dinosaurs, but knowledge of them is based entirely on a small number of fragmentary fossils. Most of the largest herbivorous specimens on record were discovered in the 1970s or later, and include the massive titanosaur "Argentinosaurus huinculensis", which is the largest dinosaur known from uncontroversial evidence, estimated to have been and long. Some of the longest sauropods were those with exceptionally long, whip-like tails, such as the "Diplodocus hallorum" (formerly "Seismosaurus") and the 33- to 35-metre-long (108–115 ft) "Supersaurus". The tallest was the "Brachiosaurus".
St. Louis Museum
A museum specimen of particular note was a fossil, the Zeuglodon, which the Complete Guide to the St. Louis Museum called "the greatest fossil in the world." The Zeuglodon was discovered in 1848 in a field in Alabama. After it was extricated from the rock in which it was found, Dr. Koch purchased the fossil for the St. Louis Museum. The fossilized animal was amphibious and resembled a whale, alligator, and serpent. Only one other fossil of this animal was known to exist at the time, which was owned by the King of Prussia. Previously a Mastodon fossil was the largest one discovered, at 20 feet. The Zeuglodon measured 96 feet. Though some doubted the authenticity of the specimen, Professor Joseph Leidy, M.D. of the University of Pennsylvania and Curator of the Academy of Natural Sciences of Philadelphia and Professor Silliman of Yale College both attested to the authenticity of the fossil.