- 1.75″ X 1.75″ metal magnet
Petrified Forest Museum Association
U.S. Geological benchmarks are permanent survey markers (also known as geodetic control points) at known elevations and are used as reference points for other topographical measurements.
Benchmarking is a favorite activity of many park visitors in which they search for and record where they have found the USGS survey markers.
|Dimensions||2.5 × .25 × 5.0 in|