A mold fossil is a type of fossil that forms when an organism, such as a plant or animal, leaves an impression in sediment. One classic example of a mold fossil is the imprint left behind by a dinosaur footprint. When a dinosaur walked across soft mud, it created a depression. Over time, this mud hardened and eventually turned into rock. If the material around the footprint dissolves away, what remains is a cavity that represents the shape of the original footprint.
In this way, the mold provides valuable information about the size and shape of the dinosaur’s foot, as well as its movement patterns. Mold fossils like these are significant because they help paleontologists understand how dinosaurs lived and moved in their environment.