Until about 1910 all of the hadrosaurs excavated had been sufficiently similar as to give palaeontologists a difficult job in identifying separate species. However in 1910 a great variety of hadrosaurs with different head features were recovered from the Red Deer River in Alberta
Examples included Kritosaurus, Saurolophus, and Prosaurolophus - all discovered by Barnum Brown. The best example was a skeleton found by Brown in 1912, complete and articulated, including some skin impressions, and with a helmet-shaped crest on its head. This he called Corythosaurus.
Brown thought it a swimming dinosaur after the pose it assumed when place in a horizontal position in restoration.
Barnum Brown: 'Corythosaurus casuaris: Skeleton, musculature and epidermis,' in Bulletin of the American Museum of Natural History, vol. 35 (1916), pp. 709-716.