William Lewis Herndon, Lieutenant, U.S.N., Exploration of the Valley of the Amazon… (1853)
“ He also knew that it was not an Indian’s boat, from the iron ring in its bow; and the only conclusion that he could come to was that the boat had broken adrift from civilized people above, and been wrecked and broken in passing the rapids. The Indians who were with Seraphim told him that ten days higher up (though the river was broken by caxoeiras) would reach white people, who rode on horseback, and had flocks and herds. Seraphim was then probably about six hundred miles from the mouth of the Purus. ”
