What is the natural cast?

The natural cast is a type of fossil that consists of an impression or mold of an organism or part of an organism that has been preserved in sedimentary rock. The sediment fills in the space left by the decomposed or dissolved organic material, creating a negative impression that replicates the shape and texture of the original organism. The natural cast can be a mold of external features, such as the shape of a shell, or internal features, such as the shape of a bone. Natural casts are formed through a natural process of fossilization that involves the burial and solidification of sediment around a dead organism or a part of it. Natural casts can provide valuable information about the morphology and structure of extinct organisms, as well as their behavior and ecology. They are often found in sedimentary rocks, such as sandstone, limestone, and shale, that have formed in marine, freshwater, or terrestrial environments.