Fossil literally means ‘to obtain from the ground’. They are remnants of living things that died long ago.
Fossilization occurs in many different ways. Sometimes the living thing is replaced entirely by other minerals, ‘from bone to stone’.
The oldest of the fossil remains found on earth are the 3.5 billion year old stromatolites that formed the earth’s oxygen atmosphere.
Considering the woolly mammoth became extinct only 10 thousand years ago there is a vast time span during which fossils have been formed, thus there are many amazing fossils yet to be found.