There's a Caribbean song that my kids sing that you may know called "Four White Horses." I'll write the lyrics below, but my question is, do the lyrics have any significant meaning or are they just Caribbean phrases linked together?

Four White Horses

Four white horses
Up the river;
Heh, hey, hey,
Up tomorrow;
Up tomorrow is a rainy day;
Come along to the shallow bay.

Shallow bay is a ripe banana,
Up tomorrow is a rainy day.

The song is lots of fun to sing to steel drum accompaniment, but, while we are singing it, I'm thinking, "What the heck does this mean?" The kids never ask; not even the precocious ones.

Thanks for any input,
WW