“The flat is by the action of the sun converted to hard salt which is more or less abundant according to the weather[;] a long continuance of very hot dry weather produces a solid mass of salt from 5 to 12 inches thick covering an [sic] hundred acres of the flat, very much resembling a large pond of water covered with rough ice.”
—from the first written account of the Salt Plains by Indian agent George Sibley in 1811

Sibley’s expedition was led by an Osage man named Sans Orielle, and was said to be the first time white men visited the Salt Plains (at the time identified as the Grand Saline).