A scientist has found a "dog-sized" dinosaur skull fragment that is from a rare evolutionary chain of dinosaurs, according to the Daily Mail.

Nick Longrich with the University of Bath's department of biology and biochemistry discovered the horned dinosaur bone and published his research, which has clued scientists in on what could have possibly happened up to 100 million years ago.

With the new evidence, they believe that the continent of North America had a divide in it that separated the East and West with a shallow sea that ran from the Gulf of Mexico to the Arctic Ocean.

This divide caused two separate evolution strands, they said, with dinosaurs stuck on either side, according to Science Daily.

"Just as many animals and plants found in Australia today are quite different to those found in other parts of the world, it seems that animals in the eastern part of North America in the late Cretaceous period evolved in a completely different way to those found in the western part of what is now North America due to a long period of isolation," said Longrich.

Dinosaurs from the East are a rare find, however, considering the amount of vegetation that often impedes any excavation attempts.

The dinosaur find was considered to be a ceratopsia, a plant-eating dinosaur and cousin of the triceratops.