The consensus appears to be that Sand's "Derry" used the tune of Lightfoot's "Wreck", not the other way 'round.

The question of earlier antecedents of the tune from which Gordon Lightfoot may have drawn his tune for "Wreck" remain unanswered; it was speculative on my part, but I still harbor a strong suspicion that such a tune must have existed in the nineteenth or possibly even the eighteenth century, based simply on the melodic pattern of it. In any case, it appears so far that Lightfoot is the modern contributor of it.

Many many thanks to all of you who have spoken up from one corner of the forest or another. This is the true richness of this wunnerful forum made manifest.

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