A buffalo jump is a cliff formation which North American Indians historically used to kill plains bison by herding the bison and driving them over the cliff. Buffalo jumps came into prevalent use by Plains hunters around the first century A.D. Buffalo jump sites are often identified by rock cairns, which signified markers designating "drive lanes", by which bison would be funneled over the cliff, breaking their legs, rendering them immobile. Often these drive lanes would stretch for miles on end. This type of hunting was most certainly a communal event, which probably lasted until around 500-600 A.D. when the bow and arrow made its way to the plains. Buffalo jump sites yield significant archaeological evidence because processing sites and camps were always nearby. Sites of interest include Head-Smashed-In, Ulm Pishkun, Madison Buffalo Jump, Dry Island, Glenrock, Big Goose Creek, Vore , and Olsen Chubbock.