Function: noun
Date: 1900
: a fossil usually with a narrow time range and wide spatial distribution that is used in the identification of related geologic formations
Function: noun
Date: 1900
: a fossil usually with a narrow time range and wide spatial distribution that is used in the identification of related geologic formations
Merriam Webster Collegiate English Dictionary. Merriam Webster - Энциклопедический словарь английского языка. 2012