Lightning whelk natural history and a new sourcing method

Artifacts made from sinistral (left-handed) whelk shells are commonly found at inland archaeological sites in eastern North America. Past attempts to source the coast of origin of these marine shells based on chemical analyses have provided tentative results. A knowledge of sinistral whelk natural history is essential before attempting shell sourcing studies. The common occurrence of sinistral whelks in the Gulf of Mexico and their uncommon occurrence along both the South Atlantic and Mid-Atlantic bights are documented. Critical biogeographical and morphological information is presented, as well as a new method of sourcing artifacts based on spire-angle measurements. Sinistral whelk artifacts from Spiro, East St. Louis, and Cahokia probably came from the eastern Gulf of Mexico.