Between abrupt and lofty mountains above West Point, the gorge through which the river flows, yet bearing its ancient name of Wey Gat, or Wind Gate, is partially obstructed at its lower entrance, by a long and narrow island, once named Martelaer's Rock, but now known as Constitution Island. In pursuance of their instructions, made with singular lack of judgment, upon this island the Commissioners landed, and under the direction of an engineer, appointed by the Colony, a work named Fort Constitution was commenced in August, 1775, and completed at a heavy expense, designed to defend, with a powerful armament of artillery, the approach up the river. Thus unfortunately located, and easily destroyed by an overlooking battery at West Point, or by a land approach on the east side of the river, the fort was abandoned and fired on the first appearance of a British force, on the 8th of October, 1777, immediately following the assault and capture by Sir Henry Clinton, of Forts Montgomery and Clinton, four miles below. Notwithstanding this early recognition of the necessity for obstructing and controling the Hudson, no attempt was made to occupy West Point until after the urgent recommendations of Washington, Governor Clinton and Lord Stirling--the latter of whom had thoroughly examined and reported upon the immediate necessity for defending this most important point. Operations were commenced by a brigade of Continental troops, under the command of General Parsons, on January 20, 1778, and before June in the same year, the work yet preserved, was thrown up on the north-east angle of the plateau, and named FORT ARNOLD. To cover the work, early in April, a body of Massachusetts troops, under Colonel Rufus Putnam, began to erect a fort constructed of earth and logs, on Mount Independence, overlooking the plain, which was named, in honor of their commander, FORT PUTNAM. The old fort yet in existence, bearing the same name, is a relic built, for the most part, in 1794. Forts Webb and Wyllis, lying to the south and named after regimental commanders, were commenced at the same time with Fort Putnam, and were designed to protect West Point from an approach southward by land. All these operations were conducted under the direction of Major-General McDougall, commanding in the Highlands; and in 1779, they were further strengthened and improved, while additional works were thrown up known as redoubts Nos. 1, 2 and 3, covering the Eagle Valley road to the west; redoubt No. 4, on Rocky Hill, in rear of Fort Putnam, and redoubts Nos. 5, 6 and 7, on Constitution Island, by Kosciuszko as the engineer, acting under the general direction of Washington, whose headquarters were established at West Point during a portion of the same year. The works known as the North and South redoubts, in rear of Garrison's Station, were erected to defend the land approach on the east side of the river.