Read it through once

At thirty miles above the mouth of Black River the water extends from Natchez on the Mississippi across to the pine hills of Louisiana, a distance of seventy-three miles, and there is hardly a spot that is not ten feet under it. The tendency of the current up the Black is toward the west. In fact, so much is this the case, the waters of Red River have been driven down from toward the Calcasieu country, and the waters of the Black enter the Red some fifteen miles above the mouth of the former, a thing never before seen by even the oldest steamboatmen. The water now in sight of us is entirely from the Mississippi.