Centrosaurus

Centrosaurus is a genus of herbivorous ceratopsian dinosaurs from the Upper Cretaceous of Canada. Their remains have been found in the Dinosaur Park Formation, dating from 76.5 to 75.5 million years ago.
"Centrosaurus" was first discovered near the Red Deer River in Alberta. Vast bonebeds of "Centrosaurus" were found in Dinosaur Provincial Park, also in Alberta. Some of these beds extend for hundreds of meters and contain thousands of individuals of all ages and all levels of completion.
This would be explained if they had perished while trying to cross a flooded river. A discovery of thousands of "Centrosaurus" fossils near the town of Hilda, Alberta, is believed to be the largest bed of dinosaur bones ever discovered. The area is now known as the Hilda mega-bonebed.
The genus "Centrosaurus" is now understood to include the fossils which used to be classified as "Monoclonius".