—, specular, association of, in Jefferson and St. Lawrence Cos., E. Emmons, xl, 81.
—, —, of volcanic origin, theory of formation of, G. Bischof, xxxvi, 237.
—, —, ibid, Mitscherlich, xxxvi, 237.
—, —, in Canada, viii, 76.
—, —, in Maine, x, 17.
—, —, in Massachusetts, i, 115, 438.
—, —, in New Hampshire, xviii, 131.
—, —, in New York, iv, 250; xxi, 329; xl, 81.
—, —, in Pennsylvania, iv, 4; xiv, 9.
—, —, in Rhode Island, ix, 46.