Joseph Nicollet, a gifted mathematician and scientist, led the first U.S. Government expedition to the pipestone quarries in 1838. On this rock ledge the explorers chiseled Nicollet's name and their initials before continuing their map-making journey on July 6. Nicollet wrote that they arrived in the valley of the famous red stone about 1:30 and that all the tribes of the north and northwest sought it for making pipes, coming there on a yearly pilgrimage to quarry it when not prevented by war. The six expedition members were Joseph N. Nicollet, John C. Fremont, Charles A. Geyer, Joseph La Framboise, J. Eugene Flandin, and James Renville.