Fossil Exhibit Trail Fossil Exhibit Trail Accessible to people in wheelchairs. The oldest Badlands rocks are forming - dinosaurs are still alive. A shallow sea reaching from the Gulf of Mexico to the Arctic Ocean divides North America into two parts. One tilts its wings, made of soft skin stretched over a strong frame of bones, and swoops low, snatching a fish from a school chased by another reptile called Plesiosaurus .
Powerful flippers propel the plesiosaur's sleek body through the water.
With quick strikes of its long snake-like neck it snaps up many fish. We can see beneath the surface where a sea turtle called Archelon paddles sedately. Ammonitids with coiled shells, and Baculites , their close relatives with straight shells, swim by jetting water from their bodies. Large pearly clams called Inoceramus live partly buried in the mud bottom. A dead body of the huge fish-eating bird, Hesperornis, lies half covered by the dark silt, and a few dinosaur bones from a carcass that floated from a nearby shore are scattered about.