Gwynedd Archaeological
Trust Regional Historic Environment Record
Felin Carnau Tide Mill, Trewyn
Primary Reference Number (PRN) : 36124 Trust : Gwynedd Community : Llanfair-yn-Neubwll Unitary authority : Ynys Mon NGR : SH29897605 Site Type (preferred type first) : POST MEDIEVAL TIDE MILL Status : Scheduled Monument
Description : The approximate location of a small mill. The rectangular stone structure survives to 1 to 2 courses high. Part of an axle is located at the W end and there are slight remains of dam walls to the W and SW. <1>
A particularly complex example of an early tide mill site. The tide was an important source of power for grinding corn from the early modern period until well into the industrial revolution, used in islands and peninsulas with insufficient drainage for conventional water mills. In Anglesey, tide mills were of importance to the local economy from the 16th century. Melin Carnog may well date from this period, the only known documentary reference to it being in 1666. Unlike other mills which are near the shore and connected to straight dams across narrow inlets, Melin Carnau was built on a small island, with dams in either direction from it across a small bay. <2>
An interesting tide mill, that may be early, perhaps 16th century? Earliest known record is Presaddfed 396, dated 1666, which includes Carnau and Carnau mill. Later references probably refer to Pandy Carnau, which was on the river, and not a tide mill, although an early 19th century map does clearly show the tide mill and dams. (Davidson 2002, p.26)
History Little is known of the history of this mill, and indeed only one archival reference has been found , which is a brief mention in a manuscript dated 1666 . The history is further confused by the construction of a fresh water mill above high tide level which was also called Melin Carnau , and was fed by the Afon Carnau. The same river would have also fed the tide mill, although there was probably little need for it, and there does not appear to be sufficient water in the present stream to drive a mill. On the coast edge is a ruined stone structure which may be the former mill house. The tide mill is not depicted on any maps yet found : John Evans map of 1796 shows Felin Wen and Bodior Mill, but does not show one at Carnau. The Ordnance Survey maps show the fresh water mill, but not the tide mill. Lucy Williams claims this mill was working into the 1870' s, but does not give her sources for this .
Archaeology
This mill differs in layout to the two adjacent mills, and more closely resembles the l61 h century mill at Llandysilio. However, this is in part dictated by the topography: the mill building is situated on an island which is centrally located at the mouth of the tidal creek. The dam, of which there are only slight remains visible, therefore ran from either side the island to the shore. The north dam is not straight, but makes use of rock outcrops close to the shore, where it runs roughly west, before turning in a dog-leg bend to the south to the island. The dam is visible at the coast end where two lines of boulders can be seen through the turf, but elsewhere it is only visible as a stone spread where a water channel has cut through the sand, and much of the dam is not visible. It is also not clear how the dam joined the island. South of the mill island the dam can again be picked up where it runs along a rock outcrop before turning south-east to re-join the mainland. Comparison of the present water channels with those shown on the 1902 OS map show that there has been considerable movement, and it is the 1902 channels which have been shown on fig. 3, as these better illustrate how the mill would have operated, although the modem channels are shown on the present survey fig . 2. The mill is a small almost square structure, which appears to have been orientated so that the wheel was on the west side. There is no clear wall on this side, although there is a cross wall inside the building, and slight traces of additional walling which suggest the former presence of a wheel race. The remaining three walls are better preserved, and are up to three courses high in places. A foundation plinth is visible on the north wall. Within the area thought to have been occupied by the wheel race is part of a wooden axle with an octagonal cast iron collar or hub around it. The axle is 600mm long and 300mm in diameter. It has been sawn at the west end, but is broken at the east end. The octagonal hub is 200mm wide, and is held onto the axle with a number of iron wedges. It has protruding ridges at each of the corners, with a further protrusion at one end of each ridge. It is assumed that spokes were attached to the hub, but by what means is not known. It is probably the central hub of the water wheel, in which case each face may have acted as a socket for a wooden spoke, although the spokes would have measured six inches or so square, which would be larger than usual. If not part of the water wheel, then it must have been part of the pit wheel. South of the mill, and within the line of the dam , is a rectangular stone spread, which may mark the location of another mill, the remains are very slight, and the exact nature of the feature is obscure. Other short lengths of walling are visible in eroded water channels east and south of the mill, which suggests the layout as surveyed is not the only system of dams employed, and that this is a multi-phase site, of which the present survey has recorded the last phase. It is not possible to relate the very small lengths of walling to any other features, or to the logical working of the present mill. It is probable that the sluice gates were sited west of the mill. The reasons for this are: there is no trace of a dam in this area; a water channel is shown here on the second edition OS map (fig. 3); it is adjacent to the wheel race, a relationship which is similar at the other mills. (Davidson, 1998).
