 On a local scale the Revett Formation consists of interbeds of hard (brittle) and soft (ductile) units; the interbed can be from inches thick to over thick.Historic exploration at the Galena and Coeur mines was carried out by following the “trend” of the veins with drifting and diamond drilling.This method was successful but it is believed that it did not allow for recognition of the larger picture of the geologic interplay of faults, veins, and stratigraphy.