No tongue and groove. Just very wide boards. I don't think they're
very old. In fact, I'm told that there are hardwood floors UNDER the
subfloor. Apparently, the hardwood floors were not in very good shape
so the previous owner (who had this house for 35 years) put a subfloor
on top of the hardwood and then put wall-to-wall carpeting over the
subfloor. I did not discover this until I took up the carpet. I was
told that "there are hardwood floors under the carpet". I wasn't told
that they were WAY under.
Thanks for the help, as always!