In the vicinity of Elk Point, South Dakota, the captains found a variety of unfamiliar minerals, including what Clark believed were arsenic and cobalt. "Capt. Lewis in proveing the quality of those minerals was near poisoning himself by the fumes & taste . . . ."
"So far, we have experienced more difficulty from the navigation of the Missouri, than danger from the Savages. The difficulties which oppose themselves to the navigation of this immence river, arise from the rapidity of it's current, it's falling banks, sandbars, and timber which remains wholy, or partially concealed in it's bed, usually called by the navigators of the Missouri and Mississippi Sawyers or planters . . . ."
The visit to Spirit Mound was among the more bizarre sidelights of the whole expedition, but evidently it was not entirely unexpected. Seventy-six years earlier, explorer Pierre La Véndrye called the place the "Dwelling of the Spirits" and reported sparkling stones and gold-colored sand . . . .
The stream, at the mouth of which the ten-man contingent from the Corps left the white pirogue, and which they followed part of the way to the storied mound, was labeled the Kenvill River on John Evans's manuscript map of the Missouri River. Gradually, during the 190 years between the day the Corps passed it in September of 1806 and the completion of the last of 15 dams on the Missouri River in 1966, the mouth of the Vermillion River migrated about 2.5 miles southeast . . . .
Here they "formed a camp in a Butifull Plain," erected a flagpole, ran up their large flag, and settled in to wait for the Sioux, whom they had invited to meet with them. On August 30, seventy-five Sioux men of the Yankton tribe, or E-hank-ton-wan, "People of the End Village," ceremoniously entered the expedition's camp, eager to parley.
The task of piloting the expedition's boats efficiently through the Missouri's windings and blind leads was the principal responsibility of Pierre Cruzatte, a French Canadian and Omaha Indian mixed-blood who, as a riverman, earned the respect and confidence of every member of the party. The many-talented Cruzatte was also admired as an interpreter, a cache digger, and a fiddler.
Here, Sergeant Gass went out with one of the hunters to retrieve the meat and hide of a buffalo the man killed the previous evening. The hunter had left his hat on the carcass "to keep off the vermin and beasts of prey," apparently believing the scent of a human would scare them away . . . ."
The huge meander called the Big Bend, or Grand Detour had been a well-known Missouri River landmark for many years when the Corps of Discovery arrived at its lower bend on September 19, 1805. At about 1:30 on the morning of 20 September 1805, Clark reported, "the Sand bar on which we Camped began to under min[e] and give way which allarmed the Sergeant on Guard . . . ."