GLO Iron Monuments

No diagram, but check section 242 of the 1930 & 1947 manuals. But then you've probably already seen these.

The earliest ones I've seen as you describe is 1913. So my guess is that the use took effect when the GLO took over the surveying and stopped using contractors. They used standard pipe 1,2 and 3 inch. Some was galvanized and some was not. The ones I've seen, they filled with concrete (the pipe) and the bottom was cut so that it could be flared out to better hold it in the ground. I'm sure there is a spec for all this some where probably around 1910.

Iron pipes show up in the 1902 Manual under "Monuments". I see no mention of iron pipes in the 1894 Manual. No length or size is given.

GLO Iron Monuments - Here are scans

1930 Manual:

1947 Manual:

This is the only reference I could find. I'm sure there are some "special instructions" somewhere that delineate their methodology explicitly. Find it could be a trick...

From "History of the Topographic Branch (Division)" DOI-USGS Circular 1341:

"...The extending level lines became, in 1896, an established phase in the basic control of topographic mapping. Permanent bench marks were set at stated intervals and, during 1896 and 1897, consisted of a copper bolt 4 inches long, and 1 inch in diameter fastened into masonry or solid rock, by driving it on a brass wedge placed in the bottom of a vertical hole, so that the top of the bolt was horizontal, and thus formed the bench mark. Triangulation stations were also marked in this manner.

In 1898, two new disks were adopted, each presenting a circular plate of bronze or aluminum, 3.5 inches in diam­eter, and 1/4-inch thick, appropriately lettered. One disk had a 3-inch stem for cementing in a drill hole, generally in the vertical walls of public buildings, bridge abutments, or other substantial masonry structures, the other type consisted of a hollow wrought iron post 4 feet in length and 3.5 inches in outer diameter, split at the bottom and expanded to 12 inches, for planting in the ground and resisting both easy subsidence and malicious extraction. The bronze cap was riveted to the top of the post (fig. 15).

On the tablet was stamped the elevation above sea level, to the nearest foot. Engineers and others finding these bench marks could obtain, if desired, the accepted elevation to the hundredth, or thousandth of a foot by communicating with the Director. In the Washington office were prepared lists of bench marks with their descriptions and elevations. As lines of levels were closed in circuits, adjustments were made in elevations. The starting points of the lines had been selected in the field as being nearest to the quadrangles to be mapped, in the hope that the elevations would be ready in advance of the topographers. To aid them in properly placing contours, temporary bench marks were set at 1 mile intervals between the permanent posts or tablets, which were set between 5 and 6 miles apart..."

fig. 15

GLO Iron Monuments - Here are scans

I believe that Section 242 of the 1930 Manual (posted above by Dave Ingram), first appeared on Page 229 of the "Advance Sheets" dated June 16, 1919 (also reprinted in 1924).

According to C.A. White (A History of the Rectangular Survey System), the Civil Appropriations Act of May 27, 1908 provided $25,000 for the purchase of iron posts to be used to monument the corners of the public land surveys.

During the period that the USGS was surveying the Forest Reserves (1897 to 1905), many iron/brass monuments were set, BUT they differed from the GLO monuments set later.

Loyal

I am an advocate for educating ourselves in the history of methods over time. That must be tempered with the fact that even the GLO had great variance in procedures among the different offices.
Knowing what to look for is important. Don't let it keep you from seeing the other footprints..

Found this very post set all over SE NM, many from 1911 or 1916, I can't remember if I saw some from 1902 or 1909, but it was one of them...