The floor is supported by split log beams and joists. Unfortunately, they've been hit by powder post beetles. This would be OK, except that there is some serious problems with later added support.
This beam was put in, but it is tilted at an angle, which means it is getting torqued. On top of that, the beam was put in rotated 90 degrees so that it isn't getting structural advantage from the direction of the grain.
Torqued, badly-installed, loaded beams split. Like this.
For the short term, we put in some screw jacks to help the beam. Long term will involve jacking the floor and adding sister joists and beams to take up more of the work.
This is depressing.