I'm unclear at the moment on the relationship between The Happy Land of Erin and The Happy Land of Canaan; the latter seems to be a Minstrel piece of the same period, and follows the same metre. Sheet music can be seen at Levy: whether or not it is essentially the same tune I'm not at all sure; nor do I have any real idea which was based on which. The fact that Kincaid identifies the Abbott tune as The Happy Land of Erin doesn't help much, as we don't know yet whether he knew it to be the same or had just assumed from the tune direction that it must be.

The Happy Land of Erin, incidentally, was the tune which Joe Wilson intended for his Sally Wheatley (he spelled it Thae Happy Land of Air-in), though it is usually sung these days to a different tune put to it by Alex Glasgow.