1856 Map... What does SM mean?

[Flipperfla]

Since we are on subject what does BM then 4 numbers mean? Boundary Marker then the marker number?

 

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[IMAUDIGGER]

I’d guess in your instance, it’s likely referring to “Bench Mark” the numbers either being the elevation, or the name of the survey monument.



In this case it’s a triangulation survey marker located at the top of a mountain.

 

[franklin]

BM stands for Boundary Marker. SM stands for Survey Marker.

 

[IMAUDIGGER]

I’d have to respectfully disagree.
When any of the following have a third order or better elevation assigned AND are monumented with a tablet, they are labeled as “BM” (bench mark);

1.) Boundary monuments (square with dot)
2.) Horizontal control (triangle)
3.) Vertical control ( x )

It’s the vertical elevation aspect that triggers the annotation.
Boundary monuments don’t typically have elevations assigned, nor are they usually numbered.

Here is what you will typically find at one of those locations labeled “BM”...at least that’s been my experience. Note “B.M.” embossed on the first tablet.

 

[teleprospector]

I’d guess in your instance, it’s likely referring to “Bench Mark” the numbers either being the elevation, or the name of the survey monument.

View attachment 1880139

In this case it’s a triangulation survey marker located at the top of a mountain.

Looks like the 5684 is the elevation since the contour lines downslope show 5000 and 4500.
Jon

 

[Gare]

What about Gold Mine and Silver Mine ?