Metheral Hill Contour Leat

Discovered by myself but jointly investigated with Stephen Holley in late 2024.

The leat comes off the Small Brook and would have flowed east to west following the contour for about 770 m. It’s about 1.2 m (4 feet) wide and in places (guessing) the leat bank is 1.2 m wide and about 0.5 m high, quite substantial. Possible evidence of a weir is at SX 62612 90507. The course of the leat is clearly visible just west of the Metheral Hill Reave at SX 62597 90521 (370.7 m above sea level) and extends to SX 62051 90171 (366.5 m ht), with a few interruptions (e.g. obliterated by land slip), where traces end.
At SX 62237 90386 (368.5 m ht) the land surface flattens out and a modern track crosses and obliterates the leat. Its course continues and passes 9 m on the south side of a boundary stone inscribed with “T” (Throwleigh). Here it changes direction, heading south. The leat is now difficult to follow because of gorse. Its course is visible on LiDAR though. At SX 62051 90171 (366.5 m ht) it meets a wide & deep channel, running south to north. The Devon HER record suggests this is either a tinners leat or a diversion channel. A fine weir is in evidence at SX 62111 89477. It could be of a later construction than the leat.

The final section of the leat is conjecture as the ground very rough with many hidden boulders and covered in thick gorse. It’s the remains of the granite structure (possible mill) nearby that strongly suggests its course.

From the diversion channel it reaches another channel (of an earlier date I think) and then heads to at third, where the remains of a possible mill are at SX 61945 90038 (361 m ht above sea level). Described and illustrated it in an article of mine: see DTRG Newsletter no. 45 November 2013 (download pdf). The latter channel was likely dug for tin ore, along an old river course.

There are no obvious signs of smelting activity or indeed stamping at the possible mill.

The ‘mill’ is sited on an ‘island’, a piece of land between a wide & deep channel and the old stream course. Using QGIS software the area of the ‘island’ measures 1.8 acres – quite close to the 2 acres of land described in the document referenced by Worth and quoted by Hemery in his book: “High Dartmoor” on page 847.

In the vicinity there’s a large mill stone (1.4 m diameter 0.3 m deep) and a rectangular pit see diagram.

It appears Eric Hemery had no knowledge of this ruin. So when he brought to our awareness the granite remains at SX 6205 9197, by the Taw River, it was this that became the location for H. Worth’s “Thomas Takfield Blowing Mill”.

Part of leat & mill: LiDAR in 3D

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Note by Stephen Holley

The main exercise of our investigation was to determine what the leat supplied i.e. the wide channel, the rectangular pit feature, the streamworks or the building (possible mill). As described above the leat is just about discernible as far as the wide channel. Past this channel the leat cannot be discerned on the ground due to the terrain and vegetation, however the LiDAR image definitely shows it continuing in the direction of the possible mill, although the leat ceases on the LiDAR image before reaching the site. Did the leat change direction and head towards the rectangular pit structure, did it continue to the possible mill or was it a water source for the valley streamworks?

The rectangular pit feature, although reminiscent of a filled-in wheelpit, has no dressing floor structures or adjacent levelled areas. The fact that the leat does not turn directly to the pit, suggests this feature is not the objective of the leat. The size of the leat suggests it has a Medieval origin. It could be supplying water to the streamworks, but unlike most such leats it is not meandering and there are no obvious streamwork reservoirs. The most likely conclusion therefore is that the leat was built to supply water to the building, which is situated below the streamwork escarpment. Coming off the escarpment the leat would be of sufficient height to power a waterwheel at the building, using a wooden launder to access the top of the waterwheel. Unfortunately, there is not an obvious leat embankment at the escarpment edge, nor is there an obvious wheelpit at the building. However, it is our feeling that despite the lack of these features, in all likelihood the leat supplied water to the building, particularly as the trajectory of the leat heads in that direction.

Although the building has been known about, it has never been listed as a tin mill. We would suggest that the location of the building below the escarpment and the discovery and trajectory of the leat, would indicate this was a tin mill and as such should be added to the list of known mill sites on Dartmoor.

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Sources:

• DTRG: “The Tinworking Landscape of Dartmoor in a European Context” (page 72)
• Eric Hemery: “High Dartmoor – Land and People” Pub. 1983
• R. Hansford Worth: “Dartmoor” Second impression 1971 pages 322 & 323
• HER no. MDV132819 “Water channel on Taw Marsh