The Theory and Practice of Surveying by John Butler Johnson 1904
http://www.archive.org/stream/theoryandpracti03unkngoog#page/n8/mode/2up
http://www.archive.org/details/theoryandpracti03unkngoog

Based on a recent discussion with a colleague concerning straightening leaning monuments, I came across this portion of Mr. Johnson’s book (Section 302, page 429 ) it reads

302. The Value of an Existing Monument is based (1) on the fact that it corresponds in character and position to a monument described on the recorded plat;
(2) on the custom to place monuments upon the completion of a survey, and on the supposition that this monument in question was set in pursuance of such custom, although no monuments are noted on the plat;
(3) on recognition by surveyors and owners of land affected by it;
(4) on the knowledge that it was placed by a competent surveyor at a time when data were accessible which are not now in existence. The value of the evidence which establishes or tends to establish the reliability of the monument is primarily a question for the judgment of the surveyor. His decision must be reviewed and defended before courts and juries when there is a difference of opinion.

The monument is valueless, or less valuable in all degrees, when there is evidence that it has been disturbed. It sometimes happens that there is no better way to establish a corner than to straighten up a stone which is leaning, but has not been thrown entirely out of the ground. Inquiry often brings out the fact that a stone, after being completely out of the ground, has been reset either by agreement of owners adjacent, or by the reckless individual who did the mischief, and is still pointed out as the stone the surveyor set. As a recognized corner such a stone has some value, i.e., it is to be supposed that it is somewhere in the right neighborhood; but if its position can be verified from other points which have not been disturbed the work should be retraced. If the original survey was made in a careless way or the corner-stones were badly set, they may help a careful man to come to an average line which shall correspond with the recorded plat. Monuments are sometimes moved or destroyed maliciously.