"Hog Rock" is an old-time breakdown from southwestern Pa. in A Major. It was collected by Samuel Bayard from Adam Smitley in Fayette County, Pa. in 1946. He was part of a musical family and learned this from his uncle Jake Smitley. He played this on the fiddle in AEae tuning. The parts are played AA'BB. The structure is unusual: the A part has 9 measures with the first ending having 3 measures. The 'B' parts of this tune and "Up Jumped Joe in the Middle of It" seemed to Bayard (1981) as though they were derived from a common ancestor. I have no idea where the title comes from. If Bayard asked his source players about the origins of the names, he didn't include them in his publications. It was printed in Bayard's Dance to the Fiddle (1981).