W.M. Ritter Lumber Co. v. Montvale Lumber Co., 169 N.C. 80:

(1915), parallel cite: 85 S.E. 438

Extrinsic evidence of a survey which located the Deed (although not called for in the Deed) may be admissible where it serves the purposes of Justice.

At 443:
>...unless we hold that what was done by Sawyer and Kelly, when they made the survey in 1871, amounted to a practical location of the first line within the rule laid down in Cherry v. Slade, 7 N. C. 82, that where it can be proved that there was a line actually run by the surveyor, which was marked and a corner made, the party claiming under the patent or deed shall hold accordingly, notwithstanding a mistaken description of the land in the patent or deed. But the insuperable obstacle to the application of this rule is that the line must have been “marked and a corner made”; and it must also appear that this was done for the purpose of making it a line of the tract of land or a call in the deed, for it is said in Safret v. Hartman, 50 N. C. 185, after quoting from Cherry v. Slade, as above:
>>“This rule presupposes that the patent or deed is made in pursuance of the survey, and that the line was marked, and the corner that was made in making the survey was adopted and acted upon in making the patent or deed, and therefore permits such line and corner to control the patent or deed, although they are not called for, and do not make a part of it. Parol evidence being thus let in for the purpose of controlling the patent or deed, by establishing a line and corner not called for, as a matter of course, it is also let in for the purpose of showing that such line and corner was not adopted and acted on in making the patent or deed, because the rule presupposes this to be the fact.”

>It may also be added at this place that the rule was adopted, against the strong but ineffectual protest of the judges long since expressed, for the sole purpose of executing the intention of the parties to the grant, and not to defeat it, and it was under the stress of some “hard case,” where a sense of justice prevailed over the long-established and safe rule, forbidding a written instrument to be contradicted or varied by parol evidence that the rule was brought into being. But conceding fully its existence, and that it is too firmly imbedded in the law of boundary to be now disturbed, we are admonished that it should be administered with caution and not carried beyond its well-defined limits. Judge Pearson once said that the rule was “a violation of principle” and should not be extended. Safret v. Hartman, supra. We may well say in this case what was so well said in Elliott v. Jefferson, 133 N.C.207,45S.E.558,64L.R.A.135,thattheerrorof the plaintiff lies in a misapprehension of the application of the rule that, in case of a discrepancy, a marked line controls the calls in the deed as to course and distance.

California Courts have loosened up from strictly prohibiting extrinsic evidence when interpreting patently unambiguous Deeds because words and phrases are not precise like mathematical formulae.