1. It has a cosmopolitan distribution and is an important index fossil in biostratigraphy. 2. It is an important index fossil in biostratigraphy. 3. Important index fossils for the Cenomanian are the ammonites " Mantelliceras mantelli ". 4. Many ecphora species are important index fossils . 5. The family includes several important index fossils . 6. They have been recorded from every continent and many are used as zonal or index fossils . 7. It has become especially useful to metamorphic and igneous geologists where index fossils are seldom available. 8. Other index fossils from Coon Creek date a little older than 70.6 million years. 9. They lived during the Jurassic Period and serve as an index fossil for that time period. 10. "Phyllograptus " species are excellent index fossils or guide fossils for identifying Ordovician rocks.
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