The Right Worshipful William Richardson Davie, Grand Master of the most Ancient and Honorable Fraternity of Freemasons in the State of North Carolina, one of the trustees of the University of the said state, and a Commissioner of the same, assisted by the other commissioners and the Brethren of the Eagle and Independence Lodges, on the 12th day of October in the Year of Masonry 5793 and in the 18th year of the American Independence, laid the cornerstone of this edifice. (Quoted in DeRespino, below)
On the back side, a Latin inscription says the same in translation. The plaque owed its remarkable rescue to Thomas Foust, UNC alumnus (class of 1903) and owner of the Clarksville Foundry.
George Moses Horton (c. 1797-1883), known as the Black Bard of UNC would have been familiar with this building. Though born into slavery, Horton taught himself to read and published three books of poetry in his lifetime. He often visited campus and sold love poems to Chapel Hill students (prices ranging from 25 to 75 cents, depending on quality). Some of his work reflects his familiarity the university. His poem The pleasures of a College life opens with the lament:
With tears I leave these Academic bowers And cease to cull the scientific flowers With tears I hail the fair succeeding train And take my exit with a breast of pain
(More of Horton's poetry is available at the link in 'sources' below).