What is the mechanism of fossil formation?
During the formation of sedimentary rocks, the dead animals of the sea or large lakes and the land carried to the sea or large lakes by river, sink down and get buried in the rocks. Supply of oxygen is limited in this condition and prevent the decay or reduces the decay rate to minimal. As a result, animal remains preserved in the rock and have formed the fossil. The hard remains of dead animals got preserved layer by layer in the sedimentary rocks. The fossils present in depper layer are earlier and upper layer had more recent fossils. There are seven different kinds of fossils. These fossils are distributed in amber, asphalt, ice, volcanic ash, peat bogs, storm dust and sand dunes. The different types of fossils, their mode of formation and suitable examples are given in the Table 6.1.