The U. S. Geological Survey did some PLSS work in the Black Hills of South Dakota in the 1890's prior to the GLO surveys. Stones were generally set for section and quarter section corners, but iron pipes were set at the township corners. This is one of two I found this past weekend. They used Bench Mark caps for the monuments, but marked them accordingly for a township corner and placed 6 notches on each cardinal edge.
This is one of the earliest PLSS iron pipe township corners out there since the GLO did not start using iron pipes until around 1908. (Except for special corners). These can be found in Oklahoma as well. This one dates to 1897. The township plats were approved and signed by Charles Walcott, Director of USGS.
USGS Township Plat
http://www.glorecords.blm.gov/details/survey/default.aspx?dm_id=239882&sid=f343ewz4.ml0&surveyDetailsTabIndex=1
I don't understand the need for the notches.
Unless it was one surveyor's unique signature.
There is an article in the American Surveyor magazine that explains how the USGS BM markers and the GLO section corners (posts/rock mounds) were near one another with nearly identical markers. A great article by some fellow named Jerry Penry wrote it.
Interesting post and informative article Jerry. Thanks for preserving the history. Great job!
The notches are the PLSS system for identifying the corner location in miles from the township lines. Township corners have 6 notches on each side.
As an example, the NE Corner of Section 10 would have 1 notch on the north, 4 notches on the west, 2 notches on the east and 5 notches on the south. Some of the instructions only had two faces notched.
Below is a notched stone from 1856. (One mile from each township line).
Robert - The USGS survey boundary crews that did this work and also ran the US Forest Reserve boundaries on the Lewis and Clarke Reserve and Black Hills Forest Reserve seemed to have still had it ingrained in them that corners needed the notches even though they were setting pipes with brass caps.