Lower Paleozoic miogeoclinal calcareous rocks of the Cassiar Terrane are intruded by the Early Cretaceous Glenlyon Batholith. Garnet-biotite and garnet-muscovite-biotite-aluminum silicatequartz geothermobarometry on the intrusive wall rocks indicate metamorphism to lower amphibolite facies at temperatures of approximately 700°C and pressures of approximately 3 kbar. Progressive deformation, indicated by porphyroblast-matrix relationships, are interpreted to be a result of minor displacements of the country rock associated with and facilitated by intrusion of the Glenlyon Batholith, followed by static heating. Isolated skarn units exist along contacts between the batholith and its wall rocks. A skarn unit is also present along a nearby north-northeast-trending dextral strike-slip fault that predates and is intruded by the batholith.