There are different kinds of fossils Petrified Molds and casts Carbon film Trace Preserved remains

Petrified Fossils Forms when water that is rich in minerals seeps into spaces in cells and then over time evaporates out. When the water evaporates it leaves the minerals behind. The minerals turn harden and turn the organism to stone

Molds and casts A mold is a hollow area in sediment where an organism used to be A cast is a copy of the shape of the organism Cast Fossil Mold fossil

Cast Mold

Carbon Film The organism leaves an extremely thin coating of carbon on a rock Gases escape from the sediment and leave carbon behind

Trace Fossils Provides evidence of animal activity. Example: Footprint / Caves Poop

Preserved Remains (body fossils) Some processes preserve the remains of organisms with little or no change Tar pits Amber Freezing