A monument is some tangible landmark established to indicate a boundary.

Wattles, Gurdon H., Writing Legal Descriptions in Conjunction with Survey Boundary Control, 1979, at 5.5

All marks of whatever description left on or near the surface of the ground, such as stones, stakes, mounds, holes, or trees specially marked and described, for the purpose of designating a particular point on the surface as a landmark, are called monuments or land bounds.

Johnson, J.B. and Leonard S. Smith, The Theory and Practice of Surveying, seventeenth edition, 1914, at 181.

Strictly speaking, the term “corner” is used to denote a point determined by surveying or other operation. The term “monument” should be used in speaking of the evidence of the location of that point – the corner.

Clark, Frank Emerson, Clark on Surveying and Boundaries: A Treatise on the Law of Surveying and Boundaries, second edition, 1939, at §378.

One very important fact that is sometimes overlooked is that a call for a monument is in actuality a call for the particular spot occupied by the monument as of the date of the deed. The monument itself is merely a symbol or object to mark the spot.

Brown, Curtis Maitland and Winfield H. Eldridge, Evidence and Procedures for Boundary Location, 1962, at §2-36.

So, we’ve established that a monument, in theory, should mark the property corner. What if the monument has been disturbed?

An important concept to understand is that a monument is not in itself a property corner but only marks the location of the property corner; that is, if the monument is moved or destroyed, the actual corner remains where it was if its location can be proved.

Cadle, Farris W., Georgia Land Surveying History and Law, 1991, at 407.

For a monument itself to be controlling it must be (1) called for, (2) identifiable, and (3) undisturbed...Once a monument is disturbed, its value as a control point ceases…

Brown, Curtis M., Boundary Control and Legal Principles, second edition, 1969, at §4.21.

Principle: An original monument to be of value must be located in the same spot occupied as of the date of the deed, waters excepted.

Brown, Curtis Maitland and Winfield H. Eldridge, Evidence and Procedures for Boundary Location, 1962, at §2-40.

When that which is fixed and stable becomes displaced and unstable, it may no longer be employed in conveyances to define boundary lines.

Skelton, Ray Hamilton, The Legal Elements of Boundaries and Adjacent Properties, 1930, at §100.

There usually is no problem if the original corners called for in the conveyance are found undisturbed.

Robillard, Walter G. and Lane J. Bouman, Clark on Surveying and Boundaries, sixth edition, 1992, at §15.08.

Artificial monuments that are placed in anticipation of and make reference to a line or description control, if found as described and if undisturbed.

Robillard, Walter G. and Lane J. Bouman, Clark on Surveying and Boundaries, sixth edition, 1992, at §15.08.

If there is a call for a monument, that monument, if discovered undisturbed and uncontradicted by the remainder of the writings, is conclusive.

Brown, Curtis Maitland and Winfield H. Eldridge, Evidence and Procedures for Boundary Location, 1962, at §2-36.

A disturbed monument may be of no value; its original spot occupied may not be identifiable.

Brown, Curtis Maitland and Winfield H. Eldridge, Evidence and Procedures for Boundary Location, 1962, at §2-36.

A good monument should possess the quality of being easily visible, certain of identification, stable in location, permanent in character, and nondependent upon measurement for its location.

Brown, Curtis M., Boundary Control and Legal Principles, second edition, 1969, at §1.11.

Errors in the measurements of distance, angles, or surface occur, but the location of original monuments, if undisturbed, is certain and conclusive as to the original location of the lines run by the original surveyor.

Brown, Curtis M., Boundary Control and Legal Principles, second edition, 1969, at §5.10.

It is well known that no measurement is exact and that different surveys will yield different measurements for the same line. Monuments, however, are exact because they mark definite points in space… In other words, monuments, as long as they remain undisturbed, will always mark the same lines, whereas courses and distances will not.

Cadle, Farris W., Georgia Land Surveying History and Law, 1991, at 402-403.

Permanent objects such as streams or rivers or the shore of a lake, highways or other lands and buildings, or stakes when referred to in the description of property conveyed are known as monuments, which are in general tangible landmarks established to indicate a boundary.  Objects, to be ranked as monuments must have certain physical properties such as visibility, permanence and stability, and definite location independent of measurements; and if the ravages of time destroy these essential elements, the object may lose its dignity as a monument for that which has become displaced and unstable can no longer be employed to define boundary lines.  Nor can a monument no longer existent, whose location is in acknowledged doubt, control over inferior calls.

Skelton, Ray Hamilton, The Legal Elements of Boundaries and Adjacent Properties, 1930, at §93.

If monuments once existing are gone, and the place where they originally stood can not be ascertained and located with precision, the courses and distances, when explicit, must govern.

Skelton, Ray Hamilton, The Legal Elements of Boundaries and Adjacent Properties, 1930, at §100.

In the description of land conveyed, the rule is, that known and fixed monuments control courses and distances… Kent’s Commentaries, IV, 515.

Gillespie, William Mitchell, A Treatise on Land Surveying, eighth edition, 1874, at 155.

A line described as running a definite distance to a definite known line or object, will be construed as running to that object, whatever distance is required. If the known object is uncertain as to position, the written distance may be used.

Raymond, William G., A Text-Book of Plane Surveying, 1896, at 216.

It is presumed that the visible objects which marked the corners when a conveyance of ownership was made indicated best the intentions of the parties concerned; hence it is agreed that a corner is established by an existing material object or by conclusive evidence as to the previous location of the object.

Davis, Raymond E. and Francis S. Foote, Surveying Theory and Practice, fourth edition, 1953, at 564.

The monument is valueless, or less valuable in all degrees, when there is evidence that it has been disturbed.

Johnson, J.B. and Leonard S. Smith, The Theory and Practice of Surveying, seventeenth edition, 1914, at 459.

A corner thus established will prevail against all other conflicting evidence if there is reason to believe that it has not been disturbed.

Davis, Raymond E. and Joe W. Kelly, Elementary Plane Surveying, fourth edition, 1969, at §18-6.

So, what do the Board Rules say regarding disturbed pins?

All corner markers and markers of pertinent reference points shall be fully described and indicated as to the material or types, size or dimensions, and whether set, found, or replaced. In the case of badly disturbed or deteriorated monuments that are replaced for the purpose of position preservation, the survey shall indicate the size, type, and material of both the found monument and the monument with which it was replaced.

State Board Rule 180-7-.07 (d) 9.

At least that is my 0.02'

• A disturbed monument may be of no value; its original spot occupied may not be identifiable.
• If monuments once existing are gone, and the place where they originally stood can not (sic) be ascertained and located with precision, the courses and distances, when explicit, must govern.
• It is presumed that the visible objects which marked the corners when a conveyance of ownership was made indicated best the intentions of the parties concerned; hence it is agreed that a corner is established by an existing material object or by conclusive evidence as to the previous location of the object.

That disturbed pin usually is the best available evidence of the corner. And as such, it should be used. We have a duty to use the best available evidence, e.g. disturbed pins, other pins, fence lines, etc. to determine the boundaries and replace or rehabilitate the disturbed pin as per the Board Rule above.

Most of the disturbed pins that we find are simply bent over. Typically, if I can spin the rebar around then I remove it, shoot the hole and replace it with the bend in the same direction that I found. Later during boundary analysis, I would decide if this location is within an acceptable tolerance. If so, I would replace it with a capped pin just as if returning to set a missing corner. Alternatively, I could straighten the bent pin and replace it i.e. rehabilitate it. And I would note all of this on the plat as per the Board Rule above.

A couple more quotes that I think apply here:

• When a man has had a training in one of the exact sciences, where every problem within its purview is supposed to be susceptible of accurate solution, he is likely to be not a little impatient when he is told that, under some circumstance, he must recognize inaccuracies, and govern his action by facts which lead him away from the results which theoretically he ought to reach. Observation warrants us in saying that this remark may frequently be made of surveyors.

Cooley, Thomas, Chief Justice, Supreme Court of Michigan, 1864-1885.

• For after all, when it comes to a question of the stability of property and the peace of the community, it is far more important to have a somewhat faulty measurement of the spot where the line truly exists than it is to have an extremely accurate measurement of the place where the line does not exist at all.

Mulford, A.C., Boundaries and Landmarks A Practical Manual, 1912, at 3.