Fran, beleive your GAVAGAN To be a variant of GAVAGHAN in Gaelic O Gaibhtheachain(GAUGHAN) of which GAVAGHAN is an alternative more phonetic form,most particular inCos.Mayo and Roscommon.This according to Mac Lysaght whose work is inclosuve of Woulfe but more recent.Hope this is helpful.Good hunting ,take care, Joe Coastal CarolinaUSA PoppaJoe@webv.net