Felin Dulas was a long, narrow two-storey stone building. In 1974 the upper floor housed a store, kiln room and the stone floor, with three pairs of new Anglesey stones in place, overdriven from a cast great spur gear 2.3m in diameter on a wooden mainshaft. On the lower floor was a store giving access to the kiln firing room, with a crude brick hearth in situ. A heavy wooden hurst frame set against the gable supported the gearing, a pitwheel 2.5m diameter driving a 1.2m diameter wallower, and immediately above this a cut-out in the wall showed the former position of the great spur wheel, the stones formerly being under-driven. The third stone was a later addition, on timbers added to the hursting. A single-storey wing at right angles to the main mill, 7.9m by 4.6m, contained two further storerooms.
Only part of the composite waterwheel, 3.9m in diameter and 1.17m wide, remained, the gudgeon bearing at the outer end of the axle completely worn away. The stones and most of the gears were unused, suggesting that the mill was being refurbished when work ceased.
The mill was converted to a dwelling in the 1990s, with a single-storey extension at first floor level on the southside, and the intention of retaining the machinery and restoring the waterwheel. Later one corner of the building collapsed, throwing a pair of stones to the ground. By 2008 the remaining machinery and timbers had become dangerous, and they were removed in July 2008. The sack hoist and timbers which supported the quant for the third pair of stones survive in situ.

Sources include:
Morris, L, 1740, Plans of the Harbours, Bars, Bays and Roads in St Georges Channel, plate 4

W J Crompton, RCAHMW, 119 November 2008.