Sergeant Floyd was a member of the Lewis and Clark expedition and the only member to die.  He died here and was buried at the top of the round knob.

Sergeant Floyd Monument

The Sergeant Floyd Monument is a monument on the bank of the Missouri River at Floyd's Bluff in what is now Sioux City, Iowa, USA. The monument honors Charles Floyd, a member of the Lewis and Clark Expedition, who died on the upstream voyage in 1804 and was buried here.

• http://en.wikipedia.org/wiki/Sergeant Floyd Monument
• Lewis and Clark: The Journey of the Corps of Discovery