No. I. From a comparison of the surveys of 1835 & 1847
No. II. From a comparison of the surveys of 1847 & 1861
No. III. From a comparison of the surveys of 1835 & 1861.
Notes:
Relief shown by soundings and contours.
From: House document No. 10 of 1868, 2nd Annual Report of the Board of Harbor Commissioners, Jan., 1868.
Shows deepening by figures in blue ink, shoaling by figures in black ink.