J. Rowe: From what I know, it sounds like the lowest level floor that you have was the original finish floor. Today a wood finish floor would be oak or other hardwood, but in your house it may or may not have been hardwood. It might be simply pi
ne or fir boards rather than oak or other hardwood. It may or may not be worth refinishing. Personally, I would use it as the subfloor and put a new finish floor on top. Hope this helped.