I found an historical note about Irishman's Wall in 'The Book of Belstone', by Chris and Marion Walpole (2002).
Quote:
"Irishman’s Wall:
“Various theories have been put forward to explain this wall, which runs east to west across Belstone Tor. It closely follows the old boundary between the Forest of Dartmoor and Belstone and South Tawton Commons between Cullever Steps and the summit of Cosdon, leading some to believe it was a deliberate marking of that boundary. Others have identified further sections of the wall, in particular along the Black-a-ven Brook, and seen it as part of an early 19th century attempt to enclose 2000 acres of Forest, probably with Duchy sanction. Matthew Crawford, one of the main ‘improvers’, is believed to be responsible for employing the ‘Irishmen’ – which may have been”
[in those days - *my remark*]
“a derogatory term for any outsider – who did the work. In Dartmoor Worker (1903) William Crossing noted those employed in the building astonished the people of the moor, by their utter contempt for boots and stockings. He also believed he had found, on the eastern side of the Taw above Holloway’s Field sheepfold, the ruins of a house that locals said the ‘Irishmen’ had lived in.
The attempt at enclosure failed. The story that comes down to us tells of irate Belstonians (including Clifford Pike’s great-great-grandparents Thomas and Ann Brock) and men from Okehampton biding their time before marching to the wall, pulling it down and driving the intruders away.”
Something is not right. This message is just to keep things from messing up down the road