- A fossil that is useful for dating and correlating the strata in which it is found.More example sentences
- This ‘dating’ is based on the presence of the ammonite index fossil Dactylioceras tenuicostatum.
- Possibly the species will prove to be an index fossil for the lower Frasnian and uppermost Givetian of the Sauerland and the Maider in Morocco, ‘Ait Ou Amar’.
- Stratigraphic occurrences of Carcineretes in the Caribbean Province suggest that this crab should be regarded as an index fossil for the early Maastrichtian.
More definitions of index fossilDefinition of index fossil in:
- The US English dictionary