On his second visit to the region, French explorer Pierre Charles Le Sueur arrives at the mouth of the Blue Earth River. At this site he builds Fort L'Huillier, named for a chemist in France who had told Le Sueur that the blue clay found at this location on his first trip was rich in copper. Le Sueur travels with two tons of the clay to New Orleans, leaving nineteen men to continue operations. Unfortunately, further testing shows that the clay contains no copper, and when Le Sueur returned to the Blue Earth River the fort had disappeared. In 1907 A. Mitchell would find on his farm seventeen decapitated skeletons and many arrowheads about a mile and a half from the fort's site. The bodies had been arranged in a straight row, buried in European fashion, leading to the conclusion that two men had survived an attack and buried their comrades. Their fates are unknown.