The day after, receiving intelligence of the evacuation of Fort Mifflin, Washington deputed Generals De Kalb and Knox to confer with General Varnum and the officers at Fort Mercer on the practicability of continuing to defend the obstructions in the channel, to report thereon, and to state the force which would be necessary for that purpose. Their report was in favor of continuing the defense. A council of the navy officers had already been called by the Commodore in pursuance of a request of the Commander-in-Chief, made before the evacuation had taken place, who were unanimously of opinion that it would be impracticable for the fleet, after the loss of the island, to maintain its station or to assist in preventing the _chevaux-de-frise_ from being weighed by the ships of the enemy. General Howe had now completed a line of defense from the Schuylkill to the Delaware, and a reinforcement from New York had arrived at Chester. These two circumstances enabled him to form an army in the Jerseys, sufficient for the reduction of Fort Mercer, without weakening himself so much in Philadelphia as to put his lines in hazard. Still, deeming it of the utmost importance to open the navigation of the Delaware completely, he detached Lord Cornwallis, about 1 in the morning of the 17th (1777), with a strong body of troops to Chester. From that place his lordship crossed over to Billingsport, where he was joined by the reinforcement from New York. Washington received immediate intelligence of the march of this detachment, which he communicated to General Varnum, with orders that Fort Mercer should be defended to the last extremity. With a view to military operations in that quarter he ordered one division of the army to cross the river at Burlington, and dispatched expresses to the northern troops who were marching on by brigades, directing them to move down the Delaware on its northern side until they should receive further orders. General Greene was selected for this expedition. A hope was entertained that he would be able not only to protect Fort Mercer, but to obtain some decisive advantage over Lord Cornwallis, as the situation of the fort, which his lordship could not invest without placing himself between Timber and Manto creeks, would expose the assailants to great peril from a respectable force in their rear. But, before Greene could cross the Delaware, Cornwallis approached with an army rendered more powerful than had been expected by the junction of the reinforcement from New York, and Fort Mercer was evacuated. A few of the smaller galleys escaped up the river, and the others were burnt by their crews. Washington still hoped to recover much of what had been lost. A victory would restore the Jersey shore, and this object was deemed so important that General Greene's instructions indicated the expectation that he would be in a condition to fight Cornwallis.