Castell Mawr hillfort / enclosure. An Iron Age settlement site with origins in the Neolithic?
Bedd yr Afanc passage grave
Castell Llwyd promontory fort (Iron Age?) on a spur above the Nevern river
Small unnamed fort on a spur above the river near Felin y Gigfran (Penybenglog group)
Castell Henllys Iron Age "village" (National Park visitor site)
Waun Mawn standing stones -- Bronze Age?
Carn Alw complex settlement traces -- Bronze Age and Iron Age
Carn Goedog -- traces of Bronze Age (and Neolithic?) settlements on the slope beneath the crags
Pentre Ifan cromlech -- Neolithic
Tycanol Wood -- assumed Iron Age fortified site
Foel Drygarn Bronze Age cairns inside an Iron Age fortified site
Carn Ingli Iron Age hillfort and abundant traces of Bronze Age / Iron Age settlement on the common
Nevern Castle -- Iron Age and maybe earlier traces beneath the medieval fortifications
Assorted standing stones -- assumed Bronze Age
Carreg Coetan cromlech, Newport. Neolithic.
Eglwyswrw motte and bailey -- on an Iron Age site?
Settlement near Cwmgloyne -- Iron Age?
Caer, Bayvil -- Iron Age fortified site?
Trafael cup-marked stone -- Neolithic cromlech?
Crugiau Cemaes barrow cemetery -- Bronze Age
There is more info about some of these sites here:
and much, much more in Neil Figgis's excellent guide called "Prehistoric Preseli".
What we see across this landscape is a long history of continuous settlement, with many sites modified from one archaeological era and into the next. Some sites have been used off and on for maybe 5,000 years, and they show that the landscape and its resources were capable of maintaining a small population which had some unique characteristics (for example, there is much debate about the "Nevern Valley" group of chambered tombs and their cultural associations....)
I know most of these sites pretty well, and I am not aware of any site to which stones have been hauled from somewhere else. The stones used are ALWAYS local -- and while there is some doubt about the origin of the Trefael Stone, that is almost certainly an erratic picked up and used more or less where it was found. Nor is there any evidence of stone colour or texture mattering in the least -- I cannot see any evidence of some stones being preferred above others. The message is that the people who built all these monuments -- ranging across the Neolithic, Bronze Age and Iron Age -- were entirely disinterested in both the origins of the stones used, and the nature of those stones.
The second key point is that in a moderately well settled community such as that of the Nevern Valley and its tributaries, there must have been considerable seasonal movement between the woodlands in the valleys and the open pastures of the Preseli Hills and Mynydd Carningli -- and even the spurs of Carnedd Meibion Owen, Waun Mawn and Frenni Fawr. That means that people were travelling, hunting and camping -- and later on moving about with domesticated animals as well. Trade, raiding expeditions, and transhumance would all have played a part. In that context, it would not be at all surprising that traces of temporary encampments would have been found at Rhosyfelin -- it is a perfect sheltered location with a handy ford across the river, probably grazing for animals on the meadows of the flood plain, and maybe even hunting to be had in the wooded valley itself. Fish traps and animal traps might well have featured. I would hazard a guess that Rhosyfelin Camp -- and maybe scores of other river valley locations in the area -- were used from Mesolithic times right through to the Roman period.
So was Rhosyfelin an important place? I doubt it. Was it a site for a bluestone quarry, linked to Stonehenge? You must be joking.......