FOSSILS

CAST FOSSILS

• formed when a mold is filled in
• example: an ammonite fossil
• trilobite fossil
• a lot of plants

cast fossil

PETRIFIED WOOD

• the stone fossil of a tree

HOW PETRIFIED WOOD OCCURS:

• a tree falls
• sediments cover it
• over time water mixes the sediments and tree cells
• the minerals in the water replace the tree cells

CARBON FILM

• carbon is an element that all living things have
• sometimes when something begins to decay, its carbon stays behind.
• it creates a film type of thing around the carcass
• this is called Carbon Film

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• this usually occurs with small animals and plants.
• happens often with fish and insects

TRACE FOSSIL

HOW THEY ARE FORMED

• an example
• an animal makes a foot print
• layers of sediment cover the hole
• the sediment becomes solid rock with the print still in the solid rock

TRACE FOSSILS ARE THINGS LIKE

• feces
• footprints
• trails
• animal holes
• plant imprints

PETRIFIED FOSSILS

• fossils replace most of all of an organism
• examples:
• petrified wood

petrified fossil of a dragonfly

petrified shark tooth fossil

Mold Fossil
~A hollow area in sediment in the shape of an organism or part of an organism
~one of the most common found fossils

mold fossil

HOW CAST ARE FORMED