This is a survey marker, also known as a benchmark. We’ve got them all over the place. Their original intention was to mark elevation and other data for mapping.
Benchmark M-51 (SW0712) was placed in Frenchman Coulee in 1934. The United States Geological Survey checked on it in 1967 and 1988.
Some folk make finding these things a hobby. Think of it as a game of Pokemon Go where the Pokemon are stationary, don’t fight, and are sometimes almost impossible to get to. I don’t seek them out, but it’s always fun to come across one.
‘Though Less Than Fear’
Camera: Argus/Cosina STL1000 (c1971)
Lens: Industar 50-2
Film: Kodak Direct Positive Pan (5246) (x-07/1977); 64ISO
Process: HC-110 100+1; 60mins
Frenchman Coulee, Washington