File:MY0039-Ruckman-Disk.jpg

This photo is a close-up of the geodetic marker above the subterranean galleries of Battery Gardner at Fort Ruckman, Nahant, MA. This marker, originally set by the U.S. Coast and Geodetic Survey (USCGS) [now the National Geodetic Survey, NGS] in 1934 and reset in 1943, was likely meant to provide a known point of reference as part of the fire control system for the battery's guns. The mark is a brass disk about 3.5 in. in diameter set in the top of a concrete column, now located about 3 in. below the surface. The PID (Permanent IDentifier) of this mark is MY0039, a code that can be used to call up its survey datasheet from the NGS, an aid to finding the mark itself. The mark was last found in good condition in December, 2010.

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