— — (natural walls) in North Carolina, J. Beckwith, v, 1.
— —, — ibid, xiv, 242.
— — in Pennsylvania, H. D. Rogers, xli, 173.
— —, a hundred and twenty miles long, in England, xxxviii, 127.
— — render limestone magnesian, xxix, 351.
—, and rocks altered by, xx, 170.
— minerals, origin of, J. D. Dana, xlix, 49.
— — of New Jersey and New York, xliv, 54.f
— — of Nova Scotia, xiv, 305; xv, 132, 204.
— tufa of the Connecticut river valley, E. Hitchcock, viii, 245; xlvii, 103.