—, fertilizing properties of, xxii, 350.
—, origin of, L. Vanuxem, xii, 92.
—, curved, mammoth cave, Ky., xlii, 206.f
— of the basin of mines, Nova Scotia, xv, 146.
—, localities of, in New York, i, 243; iv, 36; v, 39, 40; xvi, 377; xxxvi, 38.
—, —, in Maryland, xxvii, 8.
—, —, in Ohio, iv, 51, 52; v, 39; vii, 48; xvi, 158.
—, —, in Canada, viii, 71.
—, —, in Michigan, vii, 47.
—, —, in Virginia, i, 62; iv, 52.