The full name of the earliest possible geochronologic age or lowest chronostratigraphic stage attributable to the stratigraphic horizon from which the cataloged item was collected
Usage
The full name of the earliest possible geochronologic age or lowest chronostratigraphic stage attributable to the stratigraphic horizon from which objects in the collection originated.
Atlantic
,Boreal
,Frasnian
,Hirnantian
,Maastrichtian
,Bridgerian