The blocks (SUs 5674, 5675, 5676, 5677, and 5687) are all part of a mysterious C-shaped built-stone feature intersecting the tufo slab floor of the wellhead (SU 5661). Because of the lip on the southern and western edge of the slab floor,it is likely that this C-shaped feature was contemporaneous with the well, floor, and the stairs. The alignment of the feature, as viewed from the southern part of the site shows that it would have been partially obstructing access to the monumental staircase. Thus, the feature must have served some rather important function. There is no evidence thus far for any kind of use for water, so it is not likely that it was a fountain. One possible explanation is as a niche with ritual usage. Because of the opus reticulatum wall (SU 5302) and its supporting scaffolding it is impossible for us to fully understand the eastern limits of the feature as well as the northern edge of block 5677. In the NE corner between blocks 5674 and 5675, there is a cut in the bedrock along the slabs of thefloor 5661. On the northern edge of block 567 and western edge of 5674 there are heavily broken pieces of tufo blocks which are likely the remains of even more blocks which would have completed the corner.