The survey includes the American fortifications built around the Walton House on Horns Hook which were erected in early 1776 and were destroyed by a barrage from the British guns positioned across the river on the 8th September 1776, also marked on the survey. Significantly, These are the only military dispositions shown on the survey. An entry in the Diary of Archibald Robertson states; ‘Sept.4th Evening, Captain Moncrief and I were ordered to raise two Battery’s at Hell gate against Walton's House, one of 3 24-Pounders and one 3 12-Pounders, a working party of 300 men. We began to work at ½ past nine and by 5 next morning they were completed within 2 hours work of 6o men. Archibald Robertson. ‘His Diaries and Sketches in America, Book Two. 1762-1780’. The New York Public Library and The New York Times & Arno Press Reprint Edition by The New York Public Library and Arno Press Inc. 1971. ISBN 0-405-01224-1.