(1) A corner where there are no remaining traces of the monument or its accessories but whose location has been perpetuated. (2) A corner which may be recovered beyond reasonable doubt, by the testimony of the interested landowners, competent surveyors or other qualified local authorities or witnesses or by some acceptable recorded evidence. (This definition is undesirable because it applies also to corners for which the monuments or other physical evidence still exist. ) A location which depends upon the use of collateral evidence for verification can be accepted only insofar as it is supported, generally through proper relation to known corners and agreement with the field notes on distances to natural objects, stream crossings, line trees and off line blazes, etc. , or unquestionable testimony.