The BLM took over at some point. Approximately What is the last date would one expect to find pipes and caps set and stamped "GLO"?
thankks for your help
According to Oregon BLM:
"In 1946 the Bureau of Land Management (BLM) was created by the merger of the General Land Office and the Grazing Service. State offices serving one or more adjoining states were established as well as a system of district offices to manage the remaining public lands."
http://www.blm.gov/or/pubroom/lohistory.php
thanks Dave dave dave
It is probable to assume that early BLM surveyors used up the GLO marked corners that they already had in stock, so some "GLO" corners may have been set after 1946.
I have seen GLO brass caps set in 1947.
Don't forget to allow for continued use of superseded monuments after the name change.