Do all property monuments have an identifying number on them?
Setting a brass disk into an iron pipe.
Many survey markers are stamped with an identification, and in a good percentage of cases this identification has been referenced on an official map filed in a government office. However, survey markers are not necessarily property monuments. For survey markers without identifying inscriptions, a map or other source of evidence may still exist that references the marker as to its meaning and whether it is potentially a property monument. Four cases arise: (1) Markers that bear identification and are referenced somewhere; (2) Markers that bear identification but are not referenced anywhere; (3) Markers that do not bear identification but are referenced somewhere; and (4) Markers that bear neither identification nor reference anywhere.
Identification on this monument has rusted away.
A marker, in this case a property monument, illustrating case (3) is pictured right--a marker that has no identification but is referenced. Its identification was worn away after being exposed to the desert sun and sand for over 60 years. The identification formerly appeared on the central 3/8" diameter brass disk in the photo. This small disk is held in place by a tack fused into concrete that has been poured into a 3/4" diameter cut water pipe. Placed in the 1940's, the disk originally bore the inscription "LS 2334," identifying a California surveyor. Also identifying this monument is the unique size and style of the disk itself, which was deliberate on the part of the surveyor to help distinguish it from larger 5/8" disks used by most other surveyors at the time. This monument is referenced on a Record of Survey map drawn by LS 2334, and the map is easily obtainable, being a public record. The map shows where, and how, the monument was placed.
Use of a set screw to hold the disk in place. Concrete is the fixative.
A marker typical of case (1) is pictured left. It is as old as the rusted monument above, but this disk is clearly readable as "RCE 6284" even after 60 years of hot desert sun and sand. A subdivision lot corner, the engineer who set this marker used a Phillips screw to hold the 5/8" brass tag in the concrete filling of the pipe. The Phillips design makes it easy to center and hold a GPS rod atop the monument.
3/4"iron pipes are the most common type of monument stock used by surveyors today. The pipe is usually 18" long and driven vertically whenever possible, with the last inch or so of the monument left exposed. Monuments placed in streets or other surfaces that maintain traffic are driven flush. Inside the pipe, concrete may be poured to hold a stamped brass disk with the identification. Another popular means of placing identifying tags into monuments is to "cap" the pipe with a plastic insert. The cap bears the surveyor's registration number. A civil engineer who is performing a property boundary survey also identifies monuments in this way, but in California the registration of the engineer must have occurred before 1982. Plastic caps may have a lesser life span than their brass-in-concrete cousins. They may become cracked by the sun's rays, or chewed around the edges by rodents, or melted away in a wildfire.
A scribed mark in a sidewalk. No immediate meaning is conveyed by such a mark. A reference document is needed.
Some markers that fit into case (4), where there is no identification and no mapping evidence, are monuments intended to represent a property corner in the future. When unidentified markers are also actually property corners, their positions relative to other recorded or accepted monuments must be verified before acceptance. "Verification" is a formal process involving comparison to a written record. "Acceptance" of an unidentified monument without verification of written evidence may come about using physical measurement, among other things. Determination of the legitimacy of an unidentified monument is a professional skill gained through years of practical experience and attention to case law.
A magnetic nail and washer in asphalt. The washer bears no inscription.
Most other markers in case (4) are "control points." These are positions established by surveyors as locations of convenience while a survey is being conducted, sometimes called "random," "control," "mathematical," "traverse" or "chaining" points. Whether these markers bear an identification or not, they may be very confusing as to meaning to another surveyor or a layperson alike. The standard "spike and shiner," or "magnetic nail and washer," as shown left (about 1" across), are iron nails and plates designed to be recovered easily with a magnetic locator. They are often quite visible because of paint around them, further reinforcing their apparent importance and sometimes becoming the source for property corner confusion. Some practitioners use plastic caps driven into the tops of 3/4" iron pipes for control points, and by all appearances these also can be taken for property markers. Even though a cap may identify itself as "Control", or some other denotation, the information may not be readable if the cap is worn down or seen in poor light. In one case, such a control point masqueraded so well as a property corner it was used as such and walls built with respect to it even though it was five feet from the real corner.
A US Coast and Geodetic "Bench Mark" used to disclose elevation.
Some markers are neither property corners nor control points. They may bear identification and be shown on an available map, as in case (1). The inscription of the marker shown right indicates it is a "Bench Mark" set by the US Coast and Geodetic Survey. These friendly markers populate USGS maps where they are often noted with the abbreviation VABM, for Vertical Angle Bench Mark, and are often seen on USGS maps at the high points of mountains. Their original purpose was to provide a sturdy point for measuring elevations across the US. Many of the mountain peak monuments were used to perform triangulations, especially in the 1930s, for civilian and military uses. The stamped elevations on these older monuments have been superseded in the modern era of GPS.
Property line recovery
How difficult are property monuments to find?
Monuments, in the context of boundary surveying, suffer the vestiges of environmental and human elements to such a degree that they exhibit a kind of "half-life" with respect to how long they may be expected to persist. In areas of constant human activity, especially during the early development of a neighborhood's roads, fences and gardens, monuments are regularly inadvertently destroyed, creating serious problems for surveyors later when those monuments are needed for references. In time, the elements will inexorably deface, rust, rot or crumble away metal, wood and stone. Half of the monuments set for property lines in an area may be destroyed within thirty years.
Of the monuments that survive over time, the effect of wear and tear is universally present and increases the number of incidences where identification can be problematic. In some cases, markers other than property monuments are unfortunately taken for the real thing and there are myriad circumstances that cause this.
Wrong monuments
An example of an error in identification is one where the back line of a row of monuments was mistaken, as illustrated right. The lots were vacant with no visible clues such as fences or homes that otherwise could have provided orientation and supporting evidence. The angle between the two streets as illustrated added to the illusion. The construction of a home and garage was underway, but fortunately only the foundation forms had been built when the problem was discovered during an inspection.
This example illustrates common disorientation. The monuments had been placed correctly, but were not understood for the given lot.
It is more common to find an apparent marker that is close to a property corner but is not a monument. The marker is often a stake someone has placed to approximate the true corner or, about as often, to "witness" the actual monument that is known to be nearby. A witness may be mistaken for the true corner and used in lieu of it. Over time, the true marker may be destroyed, with only the witness remaining.
A concrete marker with brass disk identifier.
In the image right, a concrete pedestal is centered with a brass disk about 2 inches across, bearing the registration number of a surveyor who subsequently filed a public map as testimony of his placement of the monument. The green iron stake to the right is the witness, intended to help in relocating the monument. If the witness were not in place in this case, it would be much more difficult to locate the concrete pedestal if sand were covering it. Surveyors carry a special device that detects iron. The iron detectors cannot sense the brass disk or the concrete, so the search must then be reduced to a shovel to probe for the monument. Concrete is a material used for older types of monuments and was popular before metal detectors were invented. Over time, monuments can become buried to depths of five feet or more due to construction or flooding. Their actual positions can vary somewhat with respect to maps showing their locations, especially if they were placed using early, less accurate equipment technology or if a human error affected accuracy. This means the search radius may need to be quite large, five feet or more in some cases. If the marker being searched for is theoretically under hard pavement at an indeterminate depth below the surface, it could take a great deal of time to recover.
To recap, two common types of survey monument identification errors include (1) Misidentification of a recovered marker due to disorientation, and (2) Use of a witness stake under the belief that it is the actual true corner.
A USGLO brass cap set on an iron post in 1926.
It is hard to miss the stamped inscription on this high-contrast 2.5" diameter brass disk fused atop a 1.5" iron pipe under the disk. The USGLO (US General Land Office) placed this monument for a section corner in 1926. However, whether it's a property corner or not is another matter. Section corners define the original framework of the subdivision of land by the federal government to meet the demands of the Homestead Act. They typically defined private and public property corners for 160 acre tracts of land, but subsequent subdivisions of these original tracts of land into smaller parcels have overwritten the section lines altogether in many cases.
An inscribed "lead and disk" in a sidewalk.
The "lead and disk" shown right in a sidewalk of an urban street has seen many shoes but the inscription is clearly visible after some fifty years of wear. Lead and disks are often set as offsets to true property corners. When they are encountered in sidewalks, their offsets should never be assumed, but should always be corroborated by reference to a map that shows the stated offsets of the monuments.
One of three survey markers of the San Bernardino Meridian and baseline.
The monument left is famous as one of three set in the Initial Point area on San Bernardino Peak east of Los Angeles. The San Bernardino Initial Point is the starting point for the federal government's sectionalized survey of Southern California into townships. The brass cap is cemented into a boulder outcrop near the ridge top of the mountain.