A loose hand-written note stating Soundings are referred to mean low water asa plane of reference & are expressed in feet .... A statement of the verticaldatum used for charting in the compilation of nautical charts at the time thenote was written.
4/3/2019 11:53:27 AM
Date: 1851 ca.
Credit: NARA C&GS; Colllection
Subject: Coast and Geodetic Survey
Subject: Archive Tides