Describe two ways that fossils can form?
By fossilisation and permineralisation.
Fossilisation is caused by layers upon layers of sediment
burying the bones. As the layers of sediment above the buried bones
increases, so does the pressure on the layers of sediment lower
down. The pressure becomes so great that the bones and the
sedimentary rock fuse.
Permineralisation occurs when mineral rich water trickles in
through the sedimentary rock reaching the dinosaur bones. The
minerals fill in the cracks and spaces within the bone. Sometimes
the calcium in the bones may be replaced with these minerals. The
new minerals in the bone make them even harder and more likely to
be preserved.