I'm going to the archives of the (Roman Catholic) Archives in Boston next Monday and will be looking at marriage records for Boxton for around 1850, assuming all goes well (I haven't gotten out of Brussels yet). If you have a marriage you're looking for in the late 1840s, early 1850s, with an approximate time and you'd like me to look for it, let me know --- no promises because I'm not sure the marriages are indexed.