Scattered across America are this little bronze discs, reliques of the time before GPS. But without them GPS could never have been. They are referance marks from one of several Geodetic Surveys done in the past. They are important markers for all sorts of reason, but this one was particually accessable, just off the boardwalk that overlooks Petit Jean's gravesite.

Personally I couldn't let the chance for irony slip.

If your interested in learning more, the National Geodetic Survey maintains a webpage here -> http://www.ngs.noaa.gov