 Thomas M. Lehman has observed that Corythosaurus hasn 't been discovered outside of southern Alberta even though it is one of the most abundant Judithian dinosaurs in the region . Large herbivores like the hadrosaurs living in North America during the Late Cretaceous had " remarkably small geographic ranges " despite their large body size and high mobility . This restricted distribution strongly contrasts with modern mammalian faunas whose large herbivores ' ranges " typical [ ly ] ... span much of a continent . " 
 Thomas M. Lehman <a href='been_done' title='1'><mark>has</mark></a> observed that Corythosaurus hasn 't been discovered outside of southern Alberta even though it <a href='drop_aux' title='2'><mark>is</mark></a>one of the most abundant Judithian dinosaurs in the region . Large herbivores like the hadrosaurs living in North America during the Late Cretaceous had " remarkably small geographic ranges " despite their large body size and high mobility . This restricted distribution strongly <a href='uninflect' title='3'><mark>contrasts</mark></a> with modern mammalian faunas whose large herbivores <a href='null_genetive' title='4'><mark>'</mark></a>ranges " typical [ ly ] ... span much of a continent . " 
Thomas M. Lehman done observed that Corythosaurus hasn 't been discovered outside of southern Alberta even though it one of da most abundant Judithian dinosaurs in tdaregion . Large herbivores like the hadrosaurs living in North America during thdaate Cretaceous had " remarkably small geographic ranges " despite their large body size and high mobility . This restricted distribution strongly contrast with modern mammalian faunas whose large herbivores  ranges " typical [ ly ] ... span much of a continent . "