deposits is called as petrification.
(ii)Moulds and casts : Moulds are hardened and fossilized
mud that surrounds a dead organism. Sometimes the moulds are
found with petrified fossils of the organisms and then they are called
as casts.
(iii) Prints : Foot prints or prints of wings, skin, leaves,
stem etc. made in soft mud which subsequently became fossilized.
16.6 (b) Dating of Fossils :
It is also called as the “clock of fossils”. It is the process of determining
the age of fossils. This include the following 3 methods.
(i) Lead method (ii) Radio Carbon method (iii)
Potassium-Argon method