During Lewis and Clark's stay in this area, their days with the Teton Sioux mixed long periods of friendly visiting and good company with isolated moments of trouble and misunderstanding. William Clark wrote on September 28, 1804, that they showed as little knowledge of the Sioux's intentions as possible while remaining prepared on board for anything that might happen, keeping a strong guard all night with no sleep. Matters grew more difficult when the keelboat's anchor was lost after its line snapped, and as the expedition prepared to depart, the Sioux did not want it to leave. Black Buffalo, one of the chiefs, finally eased the situation so both sides could save face, and the expedition then continued upstream while cautiously staying away from the shore in case the Sioux changed their minds.