I often used to get flat bits of fine sandstone that had split along the plane of an extreme weather event and I would look at it and reflect on the severity of that particular flood or storm. Once I had a piece that looked as though a chicken had walked across it and I used it as a top through, among many on the section of wall that made up a sheepfold. Years later I read a piece in New Scientist about a call for fossilised dinosaur foot prints to study how they walked. It wasn't worth dismantling the bit of wall to get to it but that was my best fossil find (and loss). The one that got away! Probably a little velociraptor I would guess, or tiny T. rex type thing, walking on two legs and not dragging a tail. Evolved into a chicken.