• Fossil – a trace or the remains of a once-living thing from long ago
  • Index Fossil – a fossil of an organism that was common, lived in many areas, and existed only during a certain time span of time. Index fossils are used to help determine the age of rock layers.
  • Trace Fossil – not part of an animal or impressions of it, but rather evidence of an animal’s presence. Trace fossils may include footprints, trails, animal holes, burrows, and even feces.
  • Stratum or strata (plural) layers of sedimentary rock or soil, perhaps even igneous layers
  • Absolute age – the actual age in years of an event or object
  • Relative age – the age of an event or object in relation to other events or objects

Types of Fossils

SciShow Fossils Video Playlist

Additional Videos

Additional Resources