Laramidia

Tyrannosaurs, dromaeosaurids, troodontids, hadrosaurs, ceratopsians (including Kosmoceratops and Utahceratops[3]), pachycephalosaurs, and titanosaur sauropods are some of the dinosaur groups that lived on this landmass.

A strong latitudinal climatic gradient existed on the landmass in the final 15 million years of the Cretaceous, helping drive regional provincialism of dinosaur faunas.

Less is known about Appalachian biodiversity in the Cretaceous as few fossiliferous deposits exist in the region today and half of the fossil beds in Appalachia were destroyed during the Pleistocene ice age.

In western North America, during the Cretaceous, the dominant theropods were the tyrannosaurs, huge predatory dinosaurs with proportionately large heads built for tearing flesh from their prey.

They were scarce in Laramidia by the late Cretaceous, existing only in specialized forms like Edmontonia and Panoplosaurus while nodosaurs were thriving in Appalachia.