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.
Definition of index fossil in:
- The US English dictionary