On the western side of the Nant y Creigiau, within the stream valley is a drystone structure built into the slope. It measures 3.5 metres north to south by 2.5 metres with some evidence that there may have been another cell to the east of a similar size. The southeast corner of the structure incorporates a natural boulder and the walls are of a very rough build. J.J. Hall, Trysor, 26 March 2014