The area is predominantly underlain by massive limestone of the Upper Triassic Quatsino Formation (Vancouver Group) cut by a suite of elongate hornblende-rich dioritic intrusions that commonly contain mafic xenoliths and occupy major fractures. Mafic diorite dykes exhibit varying degrees of endoskarn alteration but exoskarn halos are generally less than 1 metre thick and, in many places, are totally lacking. Gangue mineralogy consists of garnet, pyroxene, amphibole, epidote and locally minor woolastonite.

The Paris occurrence area is underlain by Quatsino Formation limestone intruded by two small diorite bodies and diorite dykes. A distinct east trending quartz porphyry dyke transects the Paris prospect and is thought to be of Cretaceous age.

Skarn zones comprised in part of garnet, pyroxene and actinolite are developed at the limestone/diorite contacts. The skarns contain massive magnetite with disseminations and stringers of chalcopyrite, pyrrhotite, pyrite and sphalerite. A few shallow shafts have been sunk on some of the magnetite lenses. A rock sample of magnetite- garnet skarn with chalcopyrite assayed 12.86 grams per tonne gold and 22.8 grams per tonne silver (Assessment Report 18672).

Crystalline native arsenic has recently been identified by x-ray diffraction in marbles adjacent to the outer margins of the skarn (Fieldwork 1989, page 262).