Fossils are remains of organisms that lived in ancient times. Most fossils are remains of hard parts of the body such as bones, teeth, shells and exoskeletons.
Some fossils are just impressions of the body parts, e.g. footprints, leaf-vennation patterns, etc.
Fossils are usually found in sedimentary rocks which have been formed by deposition of sediments over millions of years. The majors limitations of fossil evidence includes:-
1. Only partial preservation was usually possible because softer parts decayed. The fossil records are therefore incomplete.
2. Distortion – parts of organisms might have become flattened during sedimentation.
3. Subsequent geological activities e.g. erosion, earthquakes, faulting and uplifting may have destroyed some fossils.