Regarding the Kentucky dry-set stone fences - experts in such matters have taken to placing historic plaques near some of the better-kept and (broadly-scoped) examples of the walls.   The plaques often list a construction decade and then attribute a "style" based on the construction technique. I have noted that "Irish" is the most frequent attribution on the historical plaques.

The stone is said to have been quarried from shallow trenches. Some say the quarrying and wall building were joint efforts of famine-era Irish and African-American slaves who learned the technique from the Irish.

There's a fabulous and tragic living monument to the mixing of the Irish (in this case, an O'Grady) and the African-Kentuckians by the name of Mohammed Ali.