Area riverbeds are rich with mussels whose shells, when polished, have luster suitable for processing into "pearl" buttons. In the late 19th century, mussels were harvested by brailing from the river bottoms; then they were cooked in vats for meat removal, and the shells were stockpiled on the riverbanks for shipment to the button factories.
For many years, shell-digger camps and huge piles of shells could be seen along the banks of the Ohio and Tennessee Rivers. The pearl button business became an important local industry when Capt. Louis Igert, Sr. moved his family to Paducah in 1920, and established the McKee Button Co. on So. 3rd Street.
By 1928 the national Button Producers Association proclaimed Igert's business "the largest producer of freshwater buttons in the world."
--- from a descriptive plaque along Paducah, KY floodwall
Ohio River Mussels - US Fish and Wildlife Service
Mussels near Olmstead Lock & Dam, 1999
Southernmost Illinois History Net