As the French troops approached the North River, intelligence was received that a large detachment from New York had made an incursion into Jersey, under appearances indicating an intention not to return immediately. This being thought a favourable moment for gaining the posts on the north end of York Island, a plan was formed for seizing them by a _coup de main_. General Washington fixed on the night of the second of July for making the attempt; it being supposed that the Count de Rochambeau might join the American army at Kingsbridge by that time. An aid-de-camp was therefore despatched to meet that officer with letters explaining the enterprise, and requesting him to meet the Commander-in-chief at the time and place appointed. With the proposed attack on these works, an attempt to cut off some light troops stationed on the outside of Kingsbridge at Morrissania, under the command of Colonel Delaney, was to be combined. This part of the plan was to be executed by the Duke de Lauzun, to whose legion Sheldon's dragoons, and a small body of continental troops dispersed on the lines, under the command of General Waterbury, were to be added. On the part of the Americans, all that could contribute to the success of this enterprise was done. A strong detachment commanded by General Lincoln, which fell down the river in boats with muffled oars, reached its ground undiscovered on the night of the first of July; and the army, conducted by General Washington, marched to Valentine's hill. The next day, Lincoln perceived that the detachment had returned from Jersey, that the British were encamped in great force on the north end of the island, and that a ship of war watched the landing place. These unexpected obstacles having defeated the design upon the works, he proceeded to execute his eventual orders of co-operation with the Duke de Lauzun. These were, after landing above Spiken Devil Creek, to march to the high ground in front of Kingsbridge, and there conceal his detachment, until the attack on Delaney's corps should commence. The Duke de Lauzun did not arrive, and the return of day betrayed Lincoln. A British corps advanced upon him; on hearing which, General Washington put his troops in motion, and, on his approach, the British troops retired into the island. Both parts of the plan having thus failed, the army retreated to Dobbs' ferry, where it was joined by the Count de Rochambeau on the sixth of July. The thanks of the Commander-in-chief were given to that officer in general orders, for the unremitting zeal with which he had proceeded to form his so long wished for junction with the American army; and he was requested to convey to the officers and soldiers under his command, the grateful sense which the general entertained of the cheerfulness with which they had performed so long and laborious a march at so hot a season.