guide fossil การใช้

• "Phyllograptus " species are excellent index fossils or guide fossils for identifying Ordovician rocks.
• Guided fossil-hunting treks allow ordinary folks to become amateur paleontologists
• Index fossils ( also known as guide fossils, indicator fossils or zone fossils ) are fossils used to define and identify geologic periods ( or faunal stages ).
• Fossil fans can dig it : See what you can dig up when you join this hands-on, guided fossil expedition through Old Topanga Canyon at 9 a . m . Saturday.