Transcript Fossils Remains of Ancient Plants And Animals, Evidence of Life Commonly Preserved: Hard Parts of Organisms: • Bones • Shells • Hard Parts of Insects • Woody.

Fossils
Remains of Ancient Plants And
Animals, Evidence of Life
Commonly Preserved:
Hard Parts of Organisms:
• Bones
• Shells
• Hard Parts of Insects
• Woody Material
Rarely Preserved
Soft or Easily Decayed Parts of Organisms:
• Internal Organs
• Skin
• Hair
• Feathers
Types of Fossils
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Original Material
Casts & Molds
Replacement (Petrified Wood)
Carbonized Films (Leaves)
Footprints, Tracks, Etc.
– “Trace Fossils” – Our only preserved record of
behavior of fossil organisms
Pseudofossils
Look Like Fossils But Aren't
• Dendrites
• Concretions
Pseudofossils
A Pseudofossil
Natural or Sculpture?
Johannes Beringer’s “Fossils”
Beringer’s
Book
Where Fossils Occur
Almost Exclusively in Sedimentary Rocks
• Heat of Melting or Metamorphism Would Destroy
Almost Every Type of Fossil
• Rare Exceptions:
– Some Fossils in Low-grade Metamorphic Rocks
– Trees Buried by Lava Flow
To Be Preserved, Organisms Have to Be:
• Buried Rapidly After Death
• Preserved From Decay
Good Index Fossils
• Abundant
• Widely-distributed (Global Preferred)
• Short-lived or Rapidly Changing
Correlation
The Geologic Time Scale
Quaternary
Latin, “fourth”
1822
Tertiary
Latin, “third”
1760
Cretaceous
Latin creta, “chalk”
1822
Jurassic
Jura Mountains, Switzerland
1795
Triassic
Latin, “three-fold”
1834
Permian
Perm, Russia
1841
Carboniferous
Carbon-bearing
1822
Devonian
Devonshire, England
1840
Silurian
Silures, a pre-Roman tribe
1835
Ordovician
Ordovices, a pre-Roman tribe
1879
Cambrian
Latin Cambria, “Wales”
1835