I first heard this tune in the early 1980s from some musicians from Cape Breton, Nova Scotia. 100 years earlier (1881) it had been printed in a Scottish tune book called Kohler's Violin Repository, I found the book around the same time I first heard the tune played. The tune appears on page 54 where it has the generic title "Hornpipe" and where the arrangement is credited to W B Laybourn. Composer credit is given to Laybourn for other tunes so I assume he did not compose this.
It has been facetiously credited to Vivaldi, Pachelbel and Mozart due to the structure of the "B part " of the tune. Along with Vivaldi's Hornpipe etc I have heard it called Kohler's Hornpipe as well. I decided to call it Laybourn's Hornpipe.
It was composed in C major and it sits easily in that key on the 5-string banjo. Here is notation, banjo mp3, and midi for hearing the melody with chords.
I have indicated fingering and snaps only where I found a specific way improved the sound or the ease of playing. Measure 10 could be played in several ways, using closed position G notes but I like how the open 5th string rings when sounded over and over so I prefer to play it that way. In measure 16 I've indicated an E minor chord even though the triad in the measure is EGC not EGB. It gives a better shape to the music that way I think.