Three small
ammonite fossils, each about 1.5 cm across
A fossil of a
trilobite which lived about 444 million years ago
A fossil is the remains or trace of an ancient living thing.
Fossils of animals, plants, or protists occur in sedimentary rock.
In a typical fossil, the body form is retained, but the original molecules that made up the body have been replaced by some inorganic material, such as calcium carbonate (CaCO3) or silica (SiO2). The fossil feels like, and is, made of rock. It has been mineralised or petrified (literally, turned into rock).