08.08.1927 (Duke University Archives)
The quarry was first worked circa 1760 and the stone was used in structural (foundation and chimneys, mostly) construction in and around Hillsborough.
Prior to 1925 the quarry was worked by Mayo Quarries (exact dates of operation are unknown). In 1925, the property was purchased by Duke University and the stone was quarried and shipped by railroad to Durham for use in the construction of the west campus of Duke University (information is from the NCGS).
April 1925 newspaper clip (via The Chapel Hill Weekly)
Others sold flagstones commercially (from this quarry or nearby?), as shown by this 1931 ad from the Chapel Hill Weekly: