It is most likely that Wade misjudged the location of this fort ruins. He has located it at the edge of south end of Constitution Marsh. It was more likely ruins of a fort built on Constitution Island, perhaps those originally designed and begun by Bernard Romans at the beginning of the Revolution but abandoned before their completion in favor of other forts to the south.
In The River and the Rock, the History of Fortress West Point 1775-1783, Dave Richard Palmer writes about Romans' plans for Constitution Island. "Constitution Island would become the main fortress, the paramount position. There was nothing small in his plans for fortifications on the island. Those works were to be edifices wholly worthy of their magnificent setting in the imposing Highlands. Four blockhouses, a like number of batteries and a bastioned fort were to be the fighting positions. In all 61 cannon and twenty swivel guns were now to be integrated into eleven different works. the main fort, quickly dubbed the "Grand Bastion," was to be protected by an outer stone wall 30 feet thick, 18 feet high, and nearly 500 feet long. Behind the defenses, barracks, storerooms, a guardhouse, and an ammunition magazine would complete the complex."