In February of that year a body of British cavalry crossed the East River on the ice from Long Island to Westchester. Arnold also began to fit out a boat expedition in Spuyten Duyvil Creek, which, however, was never carried out. De Lancey was making continual raids from Fordham and Morrisania on the adjoining country, and the Americans were constantly retaliating, at one time having gone so far into the territory as to destroy a pontoon bridge which the enemy had thrown across the Harlem at Morrisania and carried ofl' large numbers of cattle.^

The last important military movement in Westchester township was Washington's grand reconnoisance, in 1781, in company with Count Rochambeau and other French officers. It was part of his plan of wresting New York City from the British, or else forcing them to draw upon their troops in the South for the protection of the city. The French forces, which had landed at Newport, were marched across the country and joined Washington on the Hudson, and it was intended that both armies should move down the river to the vicinity of New York, and there, in conjunction with the fleet of De Grasse, undertake the capture of the city. The project miscarried because the British were more strongly re-enforced than had been anticipated ; but Lincoln, who had come down from Tarrytown, succeeded in getting his men into Fort Independence, just over the lower line. The enemy discovered him and an irregular skirmish ensued. De Lauzun, the French general, who was co-operating, was at that time at East Chester and heard the firing of the guns. His part of the programme was to surprise de Lancey at Morrisania, but finding that the enemy were on the alert he hastened to Lincoln's support, at Fort Independence. Washington, who, in the mean time, had the main body of the army under his command at Valentine's Hill (near the present depot of the New York City and Northern Railroad Company, at South Yonkers), also advanced.