Thanks, Sussexoak. That makes sense to me. This frame is c.1830 square rule. I haven't gotten much of a chance to study the frame, as most of it is covered over. However, I got a small glimpse of it in the bathroom we are renovating. I can't see all of the beam, but it's big, and has 2 3/4" mortises, which is kind of odd. The house next door that I'm gutting is also c.1830, I haven't seen the same flooring detail, but I've got more ceiling to pull down, so I'll be keeping an eye out for that. The scantlings for both are up and down sawmill, and the rest is hewn. There must have been a sash saw somewhere around here, as I've seen many up and down members in buildings around here, including my horse barn.
Dave