There seems to be a discontinuity in the middle Iron Age when the buildings were reconstructed and new types of pottery and artifacts were introduced, although variants of some of the older styles continued.

A body was buried in a sitting position in the middle of an approximately circular building around the time that the site was abandoned.

[3] There used to be a stone with a runic inscription at Crosskirk, now lost, dating from the period of the Norse raiders in the 9th, 10th and 11th centuries.

[4] St Mary's Chapel (Crosskirk), built around the 13th century and now ruined, is about 30 yards (27 m) south of the site.

[5] The earlier structure was an outwork that began at the edge of the promontory in the east, a 15 feet (4.6 m) thick wall or rampart of rock with an earth core.

The outwork continued west, ending in a fence made of flagstones that reached to the cliff edge at Chapel Geo.

During the next two centuries there were a series of changes and repairs to the broch, but they could not overcome its underlying weakness of design, and by the end of that period it would have been in poor shape.

Samples found at Crosskirk and Bu also include the seeds of other plants such as fat hen, sorrel and chick weed.

At nearby locations there is evidence of deep sea fishing for plaice and cod, and of consumption of venison.

There was a shallow depression around the broch and a low bank on the southwest side that may have been the remains of the outer defense wall.