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Description: This metamorphic rock, and the rock in the adjacent garden bed, are characterized by the presence of cordierite (larger rounded grains) and biotite (small black grains) porphyroblasts. Porphyroblasts are metamorphic minerals that form during prograde metamorphism and are coarser-grained than the material they are hosted in (aka: groundmass/matrix). This rock was metamorphosed twice: initial regional metamorphism during the accretion of the Meguma Terrane during the formation of the Appalachian Mountains and Pangaea, and later contact metamorphism after the intrusion of the granitoid bodies of the South Mountain Batholith. The intense heat of the cooling granitic magma metamorphosed adjacent sedimentary rocks, and resulted in the formation of metamorphic minerals including cordierite and biotite.