This is a fiddle tune, often included in the top 10 fiddle tunes.
Often connected with the Civil War, usually spelled THE GAL I LEFT BEHIND ME. Use the search box to find in the the forum and the database.. here are a few of the references you will find there:

http://www.mudcat.org/@displaysong.cfm?SongID=6342

http://www.mudcat.org/thread.cfm?threadid=80151#1458515

included in this cowboy song thread--
http://www.mudcat.org/thread.cfm?threadid=21644#231297

http://www.mudcat.org/thread.cfm?threadid=44885#986364

you can find a midi file of the tune here:
http://www.mudcat.org/midi/midibrowse.cfm?start_letter=G