The discharge of the Mississippi River is about 19,500,000,000,000 cubic feet of water per year, and the sediment it carries in suspension is estimated to weigh about 812,500,000,000 pounds. This is equivalent to about 6,714,694,400 cubic feet. It is estimated that about 750,000,000 cubic feet of sediment is rolled along the bottom, giving a total of 7,468,694,400 cubic feet as the aggregate annual load carried to the Gulf by the river. This would be adequate to cover an area one square mile in extent to the depth of 268 feet per year. [Illustration: PLATE XI. PART OF THE CATSKILLS, NEW YORK. U. S. Geol. Surv.] [Illustration: PLATE XII. Fig. 1. NEW MEXICO. U. S. Geol. Surv. Fig. 2. VIRGINIA, WEST VIRGINIA AND MARYLAND. U. S. Geol. Surv.] ANALYSES OF AMERICAN RIVER-WATERS.[33] [+Reduced to Parts per 1000 by Dr. H. J. Van Hoesen.+] +----------------------------------+------------------+----------------+ |Name of river | Bear | Croton | | | | | |Collected at | Evanston, Wy. | Reservoir, New | | | | York City | | | | | |Date | Dec., 1873 | 1881 | | | | | |Analyst | F. W. Clarke | E. Waller | | | | | |Reference |Bulletin No. 9, U.| Water supply of| | | S. Geol. Surv., | New York City,| | | p. 30 | 1881 | +----------------------------------+------------------+----------------+ |Sodium, Na | .0082 | [2].00298 | | | | | |Potassium, K | ...... | .00154 | | | | | |Calcium, Ca | .0432 | .00905 | | | | | |Magnesium, Mg | .0125 | .00336 | | | | | |Chlorine, Cl | .0049 | .00213 | | | | | |Carbonic acid, CO₂, | [3].0982 |[34].02248 | | | | | |Sulphuric acid, SO₃ | .0105 | .00441 |