is the first stone of a church, properly laid on the north-east side, as determined by the orientation of the sun on the day of the feast, or patron saint. At Beaulieu only one stone was found on the ground, and it was in this position; that of Avranches, the solitary relic of a cathedral, is still pointed out. In modern churches then most prominent or convenient corner is selected, and the corner-stone is a square block of suitable size, laid at the angle of the topmost course of the foundation. It is customary to hollow it out in a box-like manner, and to deposit within it memorial papers, etc.

Bibliography Information
McClintock, John. Strong, James. Entry for 'Corner-Stone'. Cyclopedia of Biblical, Theological and Ecclesiastical Literature. https://www.studylight.org/encyclopedias/eng/tce/c/corner-stone.html. Harper & Brothers. New York. 1870.

Bible Encyclopedias Corner-Stone

Cyclopedia of Biblical, Theological and Ecclesiastical Literature

Bible Encyclopedias
Corner-Stone