A. A thin, white vein cuts diagonally through the metamorphic rocks. It represents a fluid-filled crack that must have formed after the main metamorphic stretching.
B. A sheet of fine-grained granite (aplite) several inches thick, cuts vertically through the foliated metamorphic rock. Granite forms by solidification of molten rock below ground. A long, thin sheet of igneous rock like this is called a dike.
C. Close-up of the granite dike showing that it cuts cleanly across the foliation of the metamorphic rock.