On the 31s;t of August, 1778, they took part in the engagement at Tibbet's Brook, on the Van Cortlandt's estate, in Yonkers. They fought bravely and over forty of their number were killed. When Nimham saw that they were surrounded by the British horse, he called to his followers to fly, exclaiming, " I am old and will die here." Ridden down by Colonel Siracoe, he wounded that officer, and was on the point of pulling him from his horse, when he was shot by Simcoe's orderly.

After their great loss, in 1645, the Indians felt that they must inevitably seek other homes. Year by year the increasing tide of settlers was incompatible with Indian occupation, and, although considerable numbers continued for a long time to remain upon the lands they had sold to the whites, they gradually wasted away, many of them moving among their friends farther north, and making Stockbridge, in Massachusetts, the headquarters of the tribe, and finally the remnant that remained was removed thence to the State of Michigan. Their exit from Westchester County was very gradual, for they " loved to linger where they loved so well." At a few points they remained for a long time in considerable numbers, and Indian Hill, in Yorktown, became memorable as the last spot in Westchester County inhabited by a band of aborigines. Yet individual families remained still longer elsewhere.

The Indians vanished from Westchester as noiselessly as the morning mists disappear before the advancing day, inclosed valleys and hidden nooks retaining remnants after the great body had gone. They left behind them so few material evidences of their existence here that we find them only by accident or by careful search. But many of the names applied by them to mountains, streams and localities have been fortunately retained by the white settlers and their descendants, and in their associations and appropriateness add an interesting variety to our local nomenclature.