The American position at the Heights, strong by nature, was made still more so by defensive works. Three lines of intrenchments and redoubts were thrown across the island between One Hundred and Forty-fifth and One Hundred and Sixty-second streets; batteries were built around King's Bridge, and at several points on the heights overlooking the Harlem; and on the commanding site on the line of One Hundred and Eighty-third Street, two hundred and thirty feet above the Hudson, stood the powerful fortress called Fort Washington. Describing these works more in detail, the first of the three lines, that furthest south, was the one already referred to on which troops were digging during the action of Harlem Heights. It extended along the line of One Hundred and Forty-sixth Street. The second line, which was much stronger, was laid out a short distance above at One Hundred and Fifty-third Street. There were four redoubts in the line. Less than half a mile above, between One Hundred and Sixtieth and One Hundred and Sixty-second streets, and not extending east of Tenth Avenue, or the old Post Road, was the third line. It mainly commanded the depression in the heights which is now known as Audubon Park, and included no redoubts. In addition to this triple line, there were single breastworks and batteries at various points from Point of Rocks north, along the ridge. The high and rugged bank of the Harlem overlooking the present High Bridge was known as Laurel Hill, and at the northern extremity, at One Hundred and Ninety-second Street, there was an American battery, which the British afterwards named Fort George. On the west side, at One Hundred and Ninety-sixth Street, there was a small battery which became Fort Tryon. On the further side of Spuyten Duyvil Creek stood Fort Independence, commanding King's Bridge and its approaches.[206]
Fort Washington was a large, five-sided work with bastions, strong by virtue of its position, and important as commanding the passage of the Hudson in connection with Fort Lee (first named Constitution), opposite, on the summit of the Palisades on the Jersey side. Much labor had been expended upon it, and it was generally regarded as impregnable. The obstructions in the river consisted mainly of a line of vessels chained together, loaded with stone, and then sunk and anchored just below the surface of the river. It was expected that they would resist the passage of the British ships, which would thus be also brought to a stop under the guns from either shore, and made to suffer heavily. Both the Continental Congress and the Provincial Congress of New York had urged that no means or expense should be spared to make the obstructions effectual, in view of the serious results that would follow the enemy's possession of the river above.
Nearly a month now had elapsed since the retreat of our army to Harlem Heights, and the British had made no further progress. They had in the mean time thrown up a series of works across the island in front of their main camps at Bloomingdale and McGowan's Pass, which could be defended by a comparatively small force. On the 9th, however, they showed indications of taking the field again by sending two frigates up the Hudson. In spite of the sunken obstructions, the ships made their way through without difficulty. Then, on the morning of the 12th, Howe embarked the greater part of his army in boats, and passing through Hell Gate, under cover of a fog, landed on Throg's Neck, an arm of the Westchester coast, about six miles above. Percy was left to protect New York with three brigades. By this move the British general placed himself on Washington's flank in Westchester County, and threatened his communications. But the Neck was a poor selection for a landing-place.[207] It was practically an island, the crossings to the mainland being a causeway and fords, the opposite approaches of which were fortified by the Americans. Colonel Hand's riflemen had pulled up the planks on the bridges, and Prescott's Massachusetts were ready behind breastworks to resist any attempt on the part of the enemy to cross. Here the British wasted five days in collecting their stores, while the Americans kept a sufficient force to meet them at the causeway and vicinity. Among other regiments which relieved each other at this point were Nixon's, Varnum's, Malcom's, Graham's, and Ritzema's.
During and for some time before these movements an interesting correspondence was carried on between Washington's headquarters and a committee of the New York Convention, a portion of which may be introduced in this connection. It gives us a glimpse of the deep interest and anxiety felt in the Convention in matters affecting the protection of the State, and the internal difficulties that had to be encountered. The correspondence was conducted mainly between Lieutenant Tilghman for headquarters and Hon. William Duer for the Convention.[208] Thus, on September 20th, the latter writes to Tilghman as follows:
"I can easily imagine that Genl Howe must be both chagrined and disappointed at the Retreat of our Army from New York. I have no doubt but what he expected fully to have taken them in a net; and he certainly would have succeeded had we pertinaciously persisted in the plan of defending the city. You observe that if the passage of the North River is sufficiently obstructed that our lines will keep the enemy from making any progress in front. This is certainly true; but you must recollect that the Sound is, and must ever be, open; and if they should succeed in landing a Body of Men in Westchester County, they might, by drawing lines to the North River, as effectually hem us in, as if we were in New York. From Sutton's Neck to the North River (if I am not mistaken) is not above twelve miles."
Again on the 2d of October, speaking of the possibility of the enemy's getting on our flank or rear, Duer says:
"I wish they would delay this attempt till Genl. Lee arrives, or till Mifflin comes from Philada. I am sensible that however great General Washington's abilities and vigilance are, he must stand in need of the assistance of such excellent officers. Is Genl Greene with the Army, or is he still in Jersey? If he could be spared from that quarter his presence, I think, would be of great consequence. I am much mistaken, if he is not possest of that Heaven-born Genius which is necessary to constitute a great General.—I can scarcely describe to you my feelings at this interesting Period—what, with the situation of our enemies in your quarter and the cursed machinations of our Internal Foes, the fate of this State hangs on a single battle of importance."
Again on the 8th: