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![Great Caspar Signal - built around tree trunk theb2468.jpg Great Caspar Signal - built around tree trunk](/sites/default/files/styles/max_1300x1300/https/s3.amazonaws.com/s3-east-testmedia-noaa.woc.noaa.gov/dam/Photos/legacy/pl23_theb2468.jpg?itok=SEezfSpa)
Description
Great Caspar Signal - built around tree trunk.Note boatswain chair transporting man to top.135-foot signal --- main wood scaffold supports instrument.Tree trunk supports small scaffolding and observer at top.Western terminus of 39th Parallel Survey (Image credit: NOAA National Geodetic Survey)
Credit
NOAA National Geodetic Survey
Display Date
1878
Location
Northern California
Collection
Historic Coast & Geodetic Survey
Geodesy
Triangulation
Wooden Towers & Signal Poles
Keywords
Geodesy
Triangulation
Towers
Wooden