Hélas, hélas ! Martin is the most frequent french surname and there are a lot of Martin families in Saint Domingue. I d'nt find any Françoise in the six Saint-Martin families of Saint Domingue.The first name of your g...grandmother was most probably Françoise (François is for a man). Did you find something in the Census of Lousiana around 1815 ? Avec mes meilleurs sentiments.