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Oldest Brass Disc To Date

GEO*Trailblazer 1

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The oldest that I have found and my favorite to recover due to the ages.



Here are some pages out of the USGS Bulletin 482 published in 1911. On this page:USGS Bulletin 482 It is stated that the levels for this benchmark were originally run in 1899 for the Ravalli Quadrangle. So my guess is that is the original date for this cap.


In this page:USGS Bulletin 482 You can see the original stamping of 2815 which was X'd out at a later date. Also notice in the first page where they had an error of 3 feet on the run. That explains why a lot of USGS marks did not make the grade with USC&GS or NGS unless they were re-leveled.


Never the less very old and great finds.

Edited by CallawayMT
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Yeah! I like to search for pipe caps. There are many listed in the St. Louis, MO area -- but I have only found a few. Many around here are river survey markers. I guess that my favorite is JC0574 as it is still in good shape and has a date (1903). Also it is on the Memphis Datum.


Two more: KC0151 KC0146


A USGS pipe cap that did make it into the NGS database -- after adjustment I assume form comparison of disk stamping and the published elevation: JC0420

Edited by happycycler
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Well they do generally come as a pair. The bolt is susposedly accessed via the pipe cap. However the caps are attached tightly and I never attempt to remove them.


:D An interesting variation is KC0118 where only the bolt made it into the GeoCaching database. (The cap is listed in NGS but with no description.) I submitted a note to NGS telling them that the description for the bolt will lead you to the cap -- something that I am sure every surveyer already knows.

Edited by happycycler
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I've been happy to find three pipe caps - one of which is a USGS cap not in the NGS database.


GT1644 in Fresno County, California, was first monumented in 1902. This one is less than two miles from my office. It is one of two 1902 marks I've found.



FV0211 in Monterey County, California, was first monumented in 1909, although the date stamped in the cap is 1908.



- Kewaneh

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How do you find what are the oldest benchmarks in your area? The 2 1903 marks in my area that I know of are either offically destroyed, or have recovery notes from the 1930s listing them as destroyed, and Deb just hasn't gotten around to changing it yet

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