After excavation of all the fills, it is clear that this is accumulation in a depression that belongs to a depression in the natural soil (likely for a hut) that runs beneath the floor (2944) and feature (2851) and thus belongs to an earlier phase of occupation in the courtyard area. It is likely, then, that this is post abandonment colluvium filling the depression later truncated by the activity to the W.
fill of 2900 uncovered two separate cuts. 2904 to the Southern end is a posthole and is cut into the next layer of fill. The larger cut is a possible foundation trench
Friable light brown deposit along E edge of 2851, fills cut 2900.