I have identified the so-called “foundation structure” of the Newport Grant House as a lime kiln on the basis of two vents in the north and south sections that nobody else has seemed to notice. It was the opinion of historian James Isham (1895) that the Old Stone Tower had to be a Colonial windmill on the basis of his belief that the foundation of the Grant House had mortar and arches with triangular keystones — just like the Newport Tower; and the Colonial Grant House was built circa 1670. Therefore, the Old Stone Tower had to have been built at the same time. My investigation of the photographic archive clearly indicates that there were three sections of an ancient lime kiln; and these are out of alignment with the later Colonial House. Also, Isham noted that Colonial builders often reused abandoned foundations from earlier structures. Prior to my research, nobody has found the industrial-grade lime kiln that was needed to produce lime mortar from oyster shells in sufficient amounts to provide the five tons of lime mortar that was needed to erect the forty-ton Stone Tower. This kiln would appear to be the missing kiln. Anyway, news of this development might provoke a renewed look at the evidence.