Dinoturbation refers to disturbances in sedimentary layers caused by the passage of dinosaurs.
Some dinosaurs weighed up to 20-40 tonnes, and a slow moving dinosaur could churn up a lot of mud and dirt; even on comparatively firm ground, a dino could still cause detectable disturbances up to a meter below their footprint, resulting in an 'underprint'. And many dinosaurs, including massive sauropods such as the brontosaurus, travelled in herds consisting of dozens of individuals, sometimes stopping to fight or mate.
As a result, one might sometimes come across sandstone and mudstone that show large stretches of bumpy, messy strata. In some cases, the strata look almost ruffled, in other cases it's simply... highly perturbed. As you might expect, these areas also tend to be good places to look for dinosaur footprints (and fossils)... and if you're lucky, you might see some interesting shapes caused by fossilized squishes of mud from between the dinos' toes.