Geologic map of the Smyrna Mills quadrangle, Aroostook County, Maine

BEDROCK GEOLOGY

The sedimentary and volcanic rocks of the Smyrna Mills quadrangle have undergone weak regional metamorphism and, locally, a higher grade of thermal metamorphism. Because the original character of the regionally metamorphosed rocks is well preserved, the descriptive nomenclature of. sedimentary and volcanic rocks rather than metamorphic rocks is used.