Credit: Courtesy of the Academy of Natural Sciences, Ewell Sale Stewart Library
After Leidy reported Cope's mistake of putting the head of Elasmosaurus on the tail of the skeleton, Cope issued a circular requesting that the preprints of the drawing he had sent out be returned at his expense. He changed his original 'backwards' description of Elasmosaurus. The revised version was published in the late Spring of 1870.
