Clark's signature - Pompeys Pillar National Historic Landmark, MT. Near present day Park City, the Clark party built two dugout canoes, lashed them together, then set off downriver. The next day, they saw the large rock that Clark named "Pompy's Tower." He climbed to the top of the rock and carved his name and the date, July 25, 1806, into the soft sandstone. It is still barely visible today, protected under glass.
