Fossils are different from ordinary stones. They are the bodies of ancient animals and plants that have evolved over thousands of years.
After the death of animals and plants tens of millions of years ago, they were buried in the sand. Over time, the bodies of animals and plants will be gradually buried in the depths of the earth with the deposition of sediment. Due to the great pressure and high temperature at the bottom of the ground, the deposited sediment gradually becomes a rock layer, which is called stratum in geology. The hard parts of animal and plant corpses, such as bones and shells, also gradually become strata with the sediment and are as hard as rocks; Soft parts of animal and plant corpses, such as leaves, may also leave footprints in the stratum. In this way, fossils were formed.