In early July 1899, an excavation team of paleontologists sponsored by Andrew Carnegie discovered the fossil remains in Wyoming of what was then the longest and largest dinosaur on record. Named after its benefactor, the Diplodocus carnegii--or Dippy, as it's known today--was shipped to Pittsburgh and later mounted and unveiled at the Carnegie Museum of Natural History in 1907. Carnegie's pursuit of dinosaurs in the American West and the ensuing...