Help with Historic Aerials Symbols

[Dirt Fisherman]

Hi everyone. I am looking at a topo map from Historic Aerials and have a question about some of the symbols. In the middle of the picture here there is the triangle, the three lines under it and a block square or dot at the tip of it. Does anyone know what those symbols mean? I know there is a USGS marker in the woods around there so one of the symbols may stand for that. Does the black dot/square look like a building to you guys? I have found some old shotgun shells, and some old rusted cans there on a brief walk with the detector but am wondering if a house used to be there and it would be worth going back and detecting again. Any ideas would be helpful.

View attachment Topo.pdfView attachment Topo3.pdfView attachment TopoZoom.pdf

Thanks,
Dirt Fisherman

 

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[Mackaydon]

The triangle with a dot is called a 'spot elevation' mark, designating the highest point on a mountain or hill. The black dots are structures that would normally be occupied. The 'hollow' mark rectangles designate structures that would normally not be occupied--like greenhouses, barns, garages, etc.
Don......
PS: Welcome to Treasure Net !!

 

[Dirt Fisherman]

Great thank you for the information. I was also curious about the hollow vs black rectangles. I did some more research and the black circle at the point of the triangle may be a water tank, which also makes sense as there is an old water line shutoff in the middle of the woods there. The road leading to that spot no longer exists which is what piqued my curiosity. I guess I'll have to go back with my detector and see what I can find.

 

[Charlie P. (NY)]

A triangle and dot is also used to indicate an estimated position when charting your position.

 

[Mackaydon]

Is the cartographer's name/company on the topo?
If so, you might check with that company and ask for the key to the symbols (regarding the "III").

Don..

 

[kingvegan]

Dig on the "X"