The Aisling could quite easily date back to penal times - that's when those 'vision songs' were at thier height.
Straighty Flanagan's song sounds very typical of the post-Famine ones
I have a copy of Wright's indispensable 'Irish Ballads and Emigration Songs (whic hrefers to an Erin's Green Shore or Dixie's Green shore
I'll follow it up tomorrow, if it's any use
If you would like a digitised copy of this magnificent book PM me your e.mail address
It's too big to attach but I can dropbox you a copy
Jim