Well, actually, when revealing anything for the first time at the Dell House we expect to find something that causes some head scratching.
We know the hallway was reworked in the 1860's but had assumed it was really only the far end of the hall (when and where the atrium was added). It would seem there was previously some form of doorway here, and possibly a narrower entrance at this point given the shape outlined by the floorboard ends either side.
The patched skirting upper right is where a fireplace was. We found the remains of the hearth under the floorboards. For reasons beyond me, when removing the fireplace the skirting 'board' was done in plaster rather than wood; hence the filler'ing in progress