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![Rock cairn signal at divide between two main forks of the Ladue River theb2486.jpg Rock cairn signal at divide between two main forks of the Ladue River](/sites/default/files/styles/max_1300x1300/https/s3.amazonaws.com/s3-east-testmedia-noaa.woc.noaa.gov/dam/Photos/legacy/pl23_theb2486.jpg?itok=br5yYlUN)
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https://www.noaa.gov/media/digital-library-photo/pl23theb2486jpg-0Description
Rock cairn signal at divide between two main forks of the Ladue River.International Boundary Commission surveyor (Image credit: National Geographic Magazine July 1912)
Credit
National Geographic Magazine July 1912
Display Date
1911
Location
Alaska-Canada Boundary 141st Meridian
Collection
Historic Coast & Geodetic Survey
Geodesy
Triangulation
Wooden Towers & Signal Poles
Keywords
Geodesy
Triangulation
Towers
Wooden