Folk lyric is pretty much an undefined term prior to the 18th century. Some folksongs are derived from broadside ballads of that period, but the original tunes of most are unknown. From the way publisher's imprints were given it is not possible to put a precise date on most broadside ballads of c 1600-30. Tunes that are known are given in C. M. Simpson's 'The British Broadside Ballad and Its Music', 1966, and tunes only (not Simpson's text) are all given as ABC's in the Broadside Ballad Tunes at www.erols.com/olsonw