Fossils – remains of the objects of former geological eras, which were found by people during excavation or when they broke the surface as the result of erosion. Rather often only hard parts of the body of an animal preserves in such way – teeth and bones. Soft tissues decompose. But even though the organism itself left nothing, hollows still can be seen in a stone, which fits the form of the body. Fossils give important information about epoch in which they have been formed, e.g., about animals and plants of those days. They also allow to discover time, when they were preserved.