Since time immemorial, American Indians lived near the life-giving river and thrived on abundant fisheries, the rich resources of the uplands, and an extensive trade network in an area Captain William Clark called "the Great Mart of all this Country." At this hub of exchange, local tribes traded salmon for goods from across North America, using dried, pounded, and stored fish as a form of currency. Clark's maps showed stores of salmon along the river, and on October 24, 1805, he counted 107 stacks of dried pounded fish in different places on the rocks. During the Lewis and Clark Expedition, members of the party entered into trade for horses with native people on April 19, 1806, but trade was difficult because the native people were skilled bargainers and the outsiders had few valuable goods left. To obtain four horses, the explorers gave up two cooking kettles, leaving only one small kettle for a mess of 8 men. Beads were also a popular and valuable trade item during the expedition.