Seeking information re Civil War Mapmaker/Surveyor named "Mershon"

I've been puzzling over this name for a little while, and thought I would ask around here. The name "Mershon" is mentioned on two separate maps that I have from the Civil War. They are Confederate maps of roads and general land information around northwest Louisiana, and presumably where used during the Red River Campaign.

In one instance, a "Camp Mershon" is indicated on the map, but no camp by that name has been recorded in any history I've read (and the site itself is inaccessible/doesn't have any visible camp remnants). In another instance, a road survey map begins from a benchmark that is labeled "Mershon's commencing point of survey". Both of these points can be seen on these maps https://observablehq.com/@mradamcox/northwest-louisiana-historic-maps. Scroll down to below the maps where I have buttons to zoom you to the specific points.

Thanks for reading!

Adam