From your post, I gather that Mary Moran's marriage occurred in America. The presumed date would have been in the early 1870s. U.S. civil B/M/D rcds don't exist for this era. Therefore you should try to find church M rcds. Often these list parent's names, ages for the celebrants, and sometimes placename(s) for their origins. This info, if it survived, will help eliminate MOST (but not all) of the false positives.