Wikipedia
Gravitholus
Gravitholus (meaning 'heavy dome') was a genus of dinosaur from the late Cretaceous period ( Campanian stage, around 75 million years ago). It was a pachycephalosaur, a type of dinosaur with a thick skull made of hardened bone. It lived in what is now Alberta, Canada, and was described in 1979 by W. P. Wall and Peter Galton.
The type species is Gravitholus albertae. There is some debate amongst paleontologists as to whether the animal represents a distinct genus, or if it may be synonymous with Stegoceras. Recent publications indicate it may be a valid genus.