Don't forget even if a mill is higher up a slope, they are usually fed by leats that take water off from the stream higher up its course and bring it along the line of the contour. I was involved in the excavation of a Welsh fulling mill about 8 years ago- this stood significantly above the the nearby river but it was clearly possible to trace the line of the leat that fed it and abstracted the water from elsewhere.
But before we start leaping to conclusions surely the key thing here is that as the description you quoted says "No features were evident to confirm the building as a mill, and it appeared to be a deserted cottage, with a fireplace in each gable " - whilst the placename is certainly indicative of a mill in the general area at some point, there is absolutely nothing to suggest that the structure you have highlighted was a mill building- no evidence of a wheel pit, leat or any other of the necessary infrastructure for a mill.
From: British archaeology discussion list [[log in to unmask]] on behalf of Constantinos Ragazas [[log in to unmask]]
Sent: 12 October 2015 22:22
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Subject: [BRITARCH] Was the Rhosyfelin Neolithic bluestone "quarry" engulfed in water?
Brian John has recently posted in his blog his finding of an existing stone ruin believed to have been a post-medieval fulling mill. ( http://brian-mountainman.blogspot.com/2015/10/rhosyfelin-mill.html ).
"I think we found it [the Rhosyfelin mill] a couple of weeks ago, a few hundred yards up the valley, lost in the trees and somewhat ruinous. To get there, you just follow the public footpath from the archaeological dig site [at Crag Rhosyfelin] and the ford."
In a comment to John's post by GeoCur, this "Rhosyfelin mill" was identified as possibly being "Hen-felin"
" 'Hen-felin' is recorded on the historic Ordnance Survey maps, its name indicating a mill site. The building is still shown on modern maps (M.Ings, 2014)
The site was visited as part of the Cadw funded Mills Survey of 2012-14. Located within woodland, it is now abandoned,ruinous and overgrown. It is built, of rubble stone into the slope above a stream. The walls still stand to approximate full height but the building is now roofless. No features were evident to confirm the building as a mill, and it appeared to be a deserted cottage, with a fireplace in each gable (M.Ings, 2014).
Mill site identified from Ordnance Survey and Tithe maps. Suggested date of late 18th century to early 19th century. Present condition unknown. "
If the location of this mill is "few hundred yards up the valley" from Crag Rhosyfelin and built "into the slope above a stream", this would be strong evidence the stream (flowing some 50 yards from the Rhosyfelin rock face) was at the time of the mill operation much wider and deeper. And this wider river would likely engulf Crag Rhosyfelin in water. Raising serious questions if the Rhosyfelin rock face could possibly have been a "bluestone quarry", as Prof. Mike Parker Pearson has been claiming.
This, of course, is not a proof of anything. But it is a call to question the current claims. And a call for further independent research into the "quarry" idea of MPP.
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