 Though Cope 's scientific pursuits nearly bankrupted him , his contributions helped to define the field of American paleontology . He was a prodigious writer , with 1 @,@ 400 papers published over his lifetime , although his rivals debated the accuracy of his rapidly published works . He discovered , described , and named more than 1 @,@ 000 vertebrate species , including hundreds of fishes and dozens of dinosaurs . His proposal for the origin of mammalian molars is notable among his theoretical contributions . " Cope 's rule " , however , the hypothesis that mammalian lineages gradually grow larger over geologic time , while named after him , is " neither explicit nor implicit " in his work . 
