Polecat42 had a benchmark challenge geocache ( Lancaster Junction Benchmark Challenge - GC3CNPV) that started at the posted coordinates. But it had to be archived because the geoacaching website no longer connects to benchmarks. However, you can still search for benchmarks at National Geodetic Survey Data Explorer where you can search by the PID (Permanent IDentifier) or the location. It isn't super easy to use, but once you get used to the interface, it works. You can get to the datasheets. There are no logs, and I found few pictures. This rivet's datasheet is here
You can log some benchmarks on Waymarking, but not all of them are there. This rivet is available at Waymarking because I added it.
This cache is not at the posted coordinates. That is a good place to head toward it; I wouldn't bushwhack. Use the information below to learn more about what benchmarks are and find the coordinates in the puzzle. Remember that I like to start counting at 0.
|
KW0607 is the PID (Permanent IDentifier) of the Monel-Metal Rivet embedded in the top of the concrete culvert here. There is no lettering on it. It has some slight damage. It doesn't look like what I considered a benchmark. |
|
Although it is difficult to read in the picture, the darker grey part is a benchmark chiseled into the windowsill of the building that was the train station in Columbia. Its PID is KW0735. That building now houses a restaurant. |
|
JV4845 is the monument at the top of Turkey Hill roughly at the base of the wind turbines. The benchmark is underground below the monument. |
|
This is the Tri-State marker where Pennsylvania, Delaware, and Maryland meet. I believe we were each standing in a different state. Its PID is JU3824. |
|
Very often there are brass USGS benchmarks on the tops of mountains. This one is on Mount Bierstadt in Colorado. It's a 14-er with elevation 14,065 feet. We hiked up. This is not one you can drive up like Mount Evans or Pikes Peak. Its PID is KK2029. |
|
This benchmark is in the grass at Martic Middle School. Its PID is AB6518. It is a survey disk placed in 1993. That is much newer than most of these other examples. It is recessed in the grass and may be difficult to find. |
|
Not all benchmarks have datasheets or PIDs. This disk is on Hunsecker Mill covered bridge. I have blurred the elevation information which is needed for a geocache at that location. It has a date of 1973 which is when the bridge was replaced after being washed away in Hurricane Agnes. Read more about the bridge at its Wikipedia page. |
|
KK1946 is another unusual benchmark mount. It is at Top of the World Picnic Ground in Colorado. It's not very high relative to much of Colorado's mountainous area - only 7735 feet. But it is very easy to spot. |
|
Sometimes when a benchmark is below ground level, the USGS adds a Witness Post that is easier to spot. This one is the Witness Post for JV3920. In my experience, most marks do not have Witness Posts. The datasheet might tell you how far away the witness post is from the mark and in which direction. |
|
Finally, this Peace Pole is neither a Benchmark nor a Witness Post. But Peace Poles are something you can search for in your travels. They are a category in Waymarking as are benchmarks. This one is at the Lancaster Welcome Center on Route 30 near Greenfield. |
The Puzzle
