Brontosaur Bulges

The downward bulges in the rock layers are most likely dinosaur tracks viewed in cross section. When dinosaurs walked in soft sand, they sank in and pushed down and distorted the layers beneath their feet. The tracks later filled with more sand and were then buried by additional layers. The large bulge best fits the size and shape of the back feet of brontosaurs, sauropods often called long-necks. Bones of one kind of these 90 foot long, 40 ton giants, Apatosaurus, are found elsewhere on Dinosaur Ridge. Smaller bulges could be from juvenile brontosaurs or other kinds of dinosaurs, such as Stegosaurus. All dinosaurs walked on their toes, and their tracks often show that the toes pushed in deeper than the back of the foot. In the pictured track bulge, the deepest part was likely made by the front of the foot, indicating the direction the animal was walking.

Colorado · United States