—, coal strata, Wilkesbarre, Pennsylvania, ix, 165.
—, — — of Ohio valley, S. P. Hildreth, xxix, 1.f
—, — — —, Mariner's Mill, xxxi, 28.f
—, — —, H. Witham, xviii, 110.f
—, — —, in England, iii, 389; xxxiii, 270.
—, oolitic, remarks on, xxxiii, 107.
—, transition or Silurian, species characteristic of, T. A. Conrad, xxxv, 246.
—, —, ibid, general nature of, xxxvi, 12.
—, —, Ludlow rocks, xxx, 48.
—, in the tertiary of the Atlantic coast, T. A. Conrad, xxiii, 339.