to the right and left of the line; all marked "M C" and with the township, range and section; as

T 25 N R 14 ES 32 M C B T.

Mound of stone, on the surveyed line on the opposite side of the monument from the meanderable body of water.

Two pits, one 3 feet and one 6 feet distant, on the surveyed line on the opposite side of the monument from the meanderable body of water.

342. The interior quarter-section and all sixteenth-section corners, when required by the written special instructions.

Two bearing trees, marked (with letters and figures ending in "BT") as shown in the following diagram:

Mound of stone, in a cardinal direction from the monument, as shown (with symbol "") in the following diagram:

Two pits, in a cardinal direction from the monument, as shown (with symbol "") in the following diagram:

343. Sixteenth-section corners of minimum control.

Two bearing trees, both in the particular section which is concerned, each marked with a key letter (N, E, S or W) to indicate the position of the monument, and "" and the section; as

NS 18 BT.

W

Key

Mound of stone, in the particular section which is concerned, in a cardinal direction from the monument.

Two pits, one in each direction on the section line passing through the monument.

344. Special and auxiliary meander corners.

Two bearing trees, each marked "S M C" or "A M C," as the case may be, and the section; as

S 14 S M CBT, or

S 14 A M C B T.

Mound of stone, on the opposite side of the monument from the meanderable body of water.

Two pits, one 3 feet and one 6 feet distant, on the opposite side of the monument from the meanderable body of water.

345. Closing subdivision-of-section corners.

Two bearing trees, both in the particular section which is concerned, each marked "C C" and the section; as

S9 CCBT.

Mound of stone, on the closing line.

Three pits, one on the closing line and one each to the right and left on the line closed upon.

346. Miscellaneous angle points along irregular boundaries.

(a) Two bearing trees, where the monuments are less than 1 mile apart, one on each side of the boundary; and (b) four bearing trees, where the monuments are 1 mile or more apart, two on each side of the boundary; each marked "A P" and a serial or section number,

or both, also the initials or abbreviation of the State, reservation, giant, private claim or public land, as appropriate; as

A P 2 TR 37 B T, and
APS 14 BT

(for "angle point No. 2" on the boundary of a private claim "Tract No. 37" falling on surveyed land).

Mound of stone, on the medial line between the boundary lines intersecting at the monument, and in the direction toward the State, reservation, grant or private claim.

Two pits, one in each direction on the lines intersecting at the monument.

347. Intermediate corners along irregular boundaries.

(a) Two bearing trees, where the monuments are less than 1 mile apart, one on each side of the boundary; and (b) four bearing trees, where the monuments are 1 mile or more apart, two on each side of the boundary; each marked with the number of the mile or halfmile corner and the letter "M" (to indicate "mile corner"), and the initials or abbreviation of the State, reservation, grant, private claim or public land, as appropriate; as

47 M COLO BT, and
47 M OKLA BT

(for "47th mile" corner on the boundary

line between the States of "Colorado" and "Oklahoma").

Mound of stone, on a line at right angles to the boundary, and in direction toward the State, reservation, grant or private claim. Two pits, one in each direction on the boundary.

CHAPTER V.

RESTORATION OF LOST CORNERS.

IDENTIFICATION OF EXISTENT CORNERS.

348. It is the purpose of this chapter of the Manual to outline the guiding principles which are to be observed in the identification of existent corners, and thereafter to set forth the particular rules which are to be applied in the recovery of the position of lost corners originally established in the execution of the United States rectangular surveys.

All surveyors, whether employed by the United States or not, are cautioned to note the difference between the regulations pertaining to the establishment of the original surveys of the public lands and those relating to the subsequent identification of said official surveys and the replacement of missing monuments thereof. In the extension of the rectangular surveys it devolves upon the United States surveyor to identify the initial lines of his group and to replace all lost corners thereof. On the other hand in the subdivision of sections and in the location of property lines generally, it falls to the county or other local surveyor to identify the official corners, and where a required corner is missing the local surveyor will be called upon to recover the point. Thus it will be seen that local as well as United States surveyors are constantly called upon to search for existing evidence of original monuments, and in this work the surveyors will be guided by the same general methods. Should the search for a monument result in failure, the appropriate restorative surveying process to be observed by either surveyor will be based upon the same rules as hereinafter outlined. The text that follows draws no distinction between the duties of the two classes of surveyors.

349. The terms "corner" and "monument" are used largely in the same sense, though a distinction should be noted to clarify the subject matter of this chapter. The term "corner" is employed to denote a point determined by the surveying process, whereas the "monument" is the physical structure erected for the purpose of marking the corner point upon the earth's surface.