To show how different the Cretaceous period was, geologically speaking, from modern times, the first fossil of the plesiosaur Elasmosaurus was discovered in 1868 in landlocked Kansas--not the first place you'd think to dig up an aquatic reptile!
Elasmosaurus was distinguished by its enormously long neck: this reptile had 71 vertebrae, compared to as little as 28 for earlier plesiosaurs. This unusual feature has caused some disagreement about how Elasmosaurus hunted for fish: some paleontologists think it bent its head sideways around its body, while others believe it swam on the surface, holding its head high above the water to scope out prey.
By the way, Elasmosaurus occasioned one of the pettier disputes in 19th-century paleontology, the Bone Wars, started when the famous fossil-hunter Edward Drinker Cope mistook its long neck for its tail--and placed the head on the wrong end!
