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
3/18/2019 3:06:41 PM
Date: 1878
Credit: NOAA National Geodetic Survey
Location: Northern California
Subject: Geodesy
Subject: Triangulation
Subject: Towers
Subject: Wooden