noun
facies fossil
Technical term in geology and paleontology. A fossil that indicates the environment of deposition (facies) rather than being used for biostratigraphic correlation.
示相化石は、当時の環境を推定するのに役立つ。
Facies fossils are useful for inferring the environment of that time.
示準化石 (index fossil) is used for determining the age of strata, while 示相化石 indicates the depositional environment.
Compound of 示相 (shisō, 'indicating facies') + 化石 (kaseki, 'fossil'). The term is a direct translation of the English 'facies fossil'.