Introducing Fossils

Palaeontology is the study of ancient life. It is based on the study of fossils, which are the remains of organisms that inhabited the Earth long before we did. It is a science that teaches us about our own lives and our relationship with the planet we call home.

Fossils are the remains of ancient plant and animals or the traces of their activities. Bones, shells and teeth are the best-known fossils. But many others, from footprints to fossil dung to minuscule seeds, are also on display.

• Horns of the Gods, Bones of Giants: The word fossil comes from the Latin word that means something dug up. Until the 18th century, any unusual object dug out of the ground was called a fossil.
  Today, only the remains of once living organisms or traces of their activities qualify as fossils. Such remains must be at least 10,000 years old.
  
  
• Tears of the Gods: In Greek mythology, Zeus transformed the daughter of the sun god into poplar trees. It was an act of pity, because their brother had drowned and they were weeping bitterly. Even as trees they wept. Their tears, hardened by the sun, fell to the ground as amber. Amber is, in fact, the fossilized resin of ancient trees. Insects and other small organisms are sometimes trapped and perfectly preserved in the fossil resin.
  
  
• Unlikely Fossils: Most fossils are hard body parts such as bones, shell or teeth. But occasionally, unusual conditions permit unlikely fossils to form. Colours patterns on shells, fossilized dung, wood from the Canadian Arctic that isn't really fossilized, but has been perfectly preserved by the arid cold, and wood preserved unaltered in the oil of tar sands are but a few unlikely candidates for becoming fossils.
  
  
• Molds and Casts: Sometimes the original object dissolves completely, leaving only a cavity that retains the shape of the original in the rock. The cavity is known as a natural mold. When natural molds are filled in by minerals carried in ground water, a natural cast is formed. Natural casts preserve only the external details of a fossil.
  
  
• Lasting Impressions: Skin is rarely fossilized. But sometimes skin imprints are preserved in rocks, giving us a good idea of what an animal's outer covering looked like.
  
  
• Carbonization: Plant or animal material is sometimes reduced to a thin carbonaceous film that outlines a fossil on a rock.
  
  
• Making Tracks: The activities of ancient animals can leave marks that are preserved as fossils. Worm burrows, the mating trails of crabs, gnawed bones and dinosaur footprints all help us understand how extinct animals lived.
  
  
• From Bone to Stone: Sometimes, minerals carried in ground water accumulates within the pores of plant or animal material. The process is called permineralization. Fine details of bones structure, such as the course of blood vessels through the marrow, are preserved by permineralization and can be seen in enlarged photographs.
  
  
• Replacement: Sometimes, the original fossil dissolves, only to be replaced, bit by bit, by another material. When this happens, all interior detail is lost.
  
  

Fossils in Alberta

Alberta has a rich fossil legacy. It ranges from clams and snails found near the United States border to tiny pollen spores preserved in the McMurray tar sands. It includes some of the most significant dinosaur remains in the world. The Royal Tyrrell Museum is a celebration of this rich heritage.

This document was prepared by Wayne Hortensius, Calgary, Alberta, Canada for the Royal Tyrrell Museum Cooperating Society. All information © 1995 Royal Tyrrell Museum. All Rights Reserved.
Updated: April 8, 1995

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