Dinosaurs leave characteristic tracks when walking on an inclined sedimentary surface, such as a beach, river delta, or sand dune. Such environments have an inclination up to 30 degrees. When a dinosaur walk at an angle like this, the track left behind is asymmetrical, characterized by a bulge of displaced sediment on the downslope side. If a dinosaur was moving upslope, the bulge would be at the posterior of the track. If a dinosaur was moving downslope, the bulge would be at the anterior of the track. Using the tracks, the paleo-angle of the sedimentary bed can be estimated.