Looking straight south across Fort Peck Lake, it may seem strange that this area was called the Big Dry, but in 1805, when Lewis and Clark named it, it was not an arm of the lake but a tremendous, relatively dry riverbed. The Big Dry impressed them so much that they thought it might extend as far southeast as the Black Hills. Unlike the streams they knew in the East that flowed all year, an intermittent stream like the Big Dry was a curiosity to them. On Thursday, May 9, 1805, Captain M. Lewis wrote that they had passed the bed of the most extraordinary river he had ever beheld, as wide as the Missouri at that place, or half a mile wide, yet without a single drop of running water except for some small standing pools. That same day he also recorded seeing great quantities of game, particularly elk and buffalo, and noted that the buffalo were so gentle that the men threw sticks and stones at them to drive them out of the way. He also wrote of killing four plover of a kind he had not yet seen, identified here as the Willet, Catoptrophorus semipalmatus, and observed that its notes were louder and more varied than those of any other species of that family.