Pwllheli to Blaenau Ffestiniog Gas Pipeline
Archaeological excavations carried out by Gwynedd Archaeological Trust
forWales & West Utilities
Ymddiriedolaeth Archaeolegol GwyneddGwynedd Archaeological Trust
In 2011 Wales & West Utilities replaced a major gas pipeline from Pwllheli to Blaenau Ffestiniog, Gwynedd, North Wales. As well as being an engineering project Wales & West Utilities had to mitigate any potential damage to archaeological sites along the route so it also became a
in 1813 by an embankment, known as the Cob, so that the land behind the barrier could be drained and claimed for agriculture.
undulating upland country to Blaenau Ffestiniog, set in the heart of the mountains of Snowdonia.
Introduction
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40 50 60 70
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30
50
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SH
Criccieth
Porthmadog
Pwllheli
BlaenauFfestiniog
Harlech
Cardigan Bay
Map of the pipe route (in red) with land over 200m in brown
Wales & West Utilities Pwllheli to Blaenau Ffestiniog Gas Pipeline
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Recording included photographs, scaled plans and detailed notes.
ethodology
Monitoring topsoil stripping
Initial investigation of potential archaeology
Excavation and recording
Wales & West Utilities Pwllheli to Blaenau Ffestiniog Gas Pipeline
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Wales & West Utilities Pwllheli to Blaenau Ffestiniog Gas Pipeline
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A full report has been produced with detailed descriptions and specialist reports and this is
Aberystwyth.
Worked wood from a burnt mound near Pentrefelin
obtaining radiocarbon dates.
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SF22
Graph showing the calibration of a radiocarbon date
Drawing of a utilized pebble
Two of the very few worked ints found
Soil micromorphology samples
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B
not known, though suggested uses for the hot water pits include cooking, bathing, saunas, dying, fulling and beer making.
A burnt mound exposed near Pentrefelin (right) with the pit that was excavated beneath it (above). This site dated to the 7th century AD but looks just like the late Neolithic and Bronze Age mounds
Few burnt mounds were
project found 11 burnt mounds
concentrated around Pentrefelin.
these sites radiocarbon dates are needed. As more sites are dated it has become clear that they were
was carried out on the mounds found in this project and it was
Wales & West Utilities Pwllheli to Blaenau Ffestiniog Gas Pipeline
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Wales & West Utilities Pwllheli to Blaenau Ffestiniog Gas Pipeline
David Chapman of Ancient Arts reconstructing how beer might have been made in a burnt mound trough
Next to Pentrefelin was a large area
rounded pits dug into the clay, but one was
lined with wood. All the pits are thought
many burnt mounds this site lay next to
obtained.
collected nearby and included alder that
it burn better.
from before 2500 BC, through to the
episodes, each related to digging and
abandoned for centuries then used again
trough was used.
It is not yet clear what the burnt mounds were
heated and probably kept boiling for some time.
but there is rarely any bone or other rubbish left on the sites. Bathing, washing clothes or fulling cloth
a recent suggestion and this has been tested by experimental archaeologists.
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stream
Site near Pentrefelin repeatedly used for burnt mounds. The grey represents the burnt mound spreads, which overlay natural channels (grey dashed lines); drains (black dashed lines) ran through the site.
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Pollen Analysis A column of peat was taken from a marsh next to the large burnt mound at Pentrefelin. Pollen
being used and this showed a largely wooded landscape, with alder carr woodland along the
grew back after each of these short episodes.
was also expanding.
until woodland was only present in isolated stands, hedgerows and along streams, and the landscape was much as it is today. Some pine pollen represents the introduction of foreign trees in plantations from the 18th century onwards.
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10152025303540455055606570
Dep
th (c
m)
2140 ± 30
3020 ± 30
20 40
Betula
100 200
Alnus g
lutino
sa
20 40
Quercu
s
Pinace
ae
Sorbus
-type
UlmusCarp
inus
IlexAce
r cam
pestr
e
204060
Corylus
avell
ana-t
ype
Sambu
cus n
igra
Hedera
Bryonic
a dioi
ca
Lonic
era
SalixEric
a-und
iff
Callun
a
Cereal-
type
Avena
-Tritic
um -ty
pe
Total
cerea
l-type
2040
Poace
ae
2040
Cyper
acea
e
Rumex
undif
f.
Plantag
o und
iff.
Ranun
culus
-type
Rosac
eae-u
ndiff
Alchem
illa-ty
pe
Filipe
ndula
Potenti
lla-ty
pe
Hyper
icum pe
rforat
um-ty
pe
Hyper
icum el
odes
type
Lactu
ceae
undif
f
Artemisia
-type
Cirsium
-type
Solida
go-vi
gaur
ea-ty
pe
Achille
a-typ
e
Apiace
ae-un
diff
Rubiac
eae-u
ndiff
Stellar
ia ho
lostea
Caryop
hylla
ceqa
e und
iff.
Sinaps
is
Urtica d
ioca
Vicia ty
pe
Vicia cr
acca
Campa
nula-
type
Cheno
podia
ceae
undif
f
Calyste
gia
Anchu
sa ar
vens
is
Scutel
laria
Stachy
s sylv
atica
type
Symph
ytum
Others
Pteridi
um
20 40
Pterop
sida (
monole
te) in
det.
20
Polypo
dium
Pterop
sida (
trilete
) inde
t.
Sphag
num
Conce
aled/C
rumple
d
Degrad
ed
Total
Inde
termina
te
Myriop
hyllu
m-undif
f
Equisi
tum
Potamog
eton
Sparg
inium
Typh
a lati
folia
20
Charco
al
20406080100
Tree
sShru
bs
Dwarf sh
rubs
Herbs
Zone
M3-vi
M3-v
M3-iv
M3-iii
M3-ii
M3-i
Trees Shrubs Dwarf shrubs Herbs Spores Indet. Aquatics
Pwllheli M3 (%TLP-A lnus)
Pollen diagram from Pentrefelin
Pollen grains seen under the microscope (from the left: lime, alder, hazel, grass)(Department of Geography, Royal Holloway College)
Wales & West Utilities Pwllheli to Blaenau Ffestiniog Gas Pipeline
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Wales & West Utilities Pwllheli to Blaenau Ffestiniog Gas Pipeline
the other pit held some fragments from the pyre that the body was burnt on.
known as cists, but there was no sign that these had been used on this site, nor that the burial had
B
Llanystumdwy
A497
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Above: site of cremation burial (black dot) (black dashed line = pipe route) (© Crown copyright Ordnance Survey. All rights reserved).Left: plan of the two small pits containing the cremation burial and pyre remains
cremations in urns within a circular ditched enclosure.
earlier than the Gas Pipeline
they could represent different burials of different status
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of settlement in the area but it seems likely that there was an Iron Age settlement somewhere nearby.
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Corn drier
Iron Age Pits
Above: plan of pits and corn drier
Left: pit with heat-cracked stones
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SF10
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SF18.2
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Wales & West Utilities Pwllheli to Blaenau Ffestiniog Gas Pipeline
Corn drier during excavation showing stone lining
used specially designed
were like this one, dug into the ground and built in the corner of a
rubbers for grinding grain.
placed on the surface of the
worn surface where the stones
had been broken by the heat
used in a nearby settlement.
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sample suggest that the site was within woodland. A charcoal sample and a cockle shell from the deposit were radiocarbon dated, showing that
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Shell midden deposit built up against a rock outcrop
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Wales & West Utilities Pwllheli to Blaenau Ffestiniog Gas Pipeline
smithing hearth. Radiocarbon dates showed that the smithy was used in the late 12th or early 13th century AD.
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Above: site of smithy (black dot) shown on 1889 map (black dashed line = pipe route, grey dashed line = route of A497).Left: plan of the smithy pit and adjacent larger pit
A layer of wood and branches was found under
density of the deposit and the presence of smaller chips of wood suggests that this material had not
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Location of possible causeway (black dot) on 1889 map (dashed line = pipe route).
Examples of worked wood from the site (above and right)
Wales & West Utilities Pwllheli to Blaenau Ffestiniog Gas Pipeline
Maentwrog
structure. An attempt to date the wood by dendrochronology failed so two pieces of bark were radiocarbon dated and this showed that the possible structure dated to the second half of the
Princes of Gwynedd.
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Wales & West Utilities Pwllheli to Blaenau Ffestiniog Gas Pipeline
wood, just the closest wood being used, including species such as alder, which are generally not
wood was left on the ground for a considerable time after cutting.
A Changing Landscape
was being produced from oak woodlands
burial showed that only oak was used for fuel
ensure that there was enough wood of the right type to build the pyre.
type of land the cereals were grown on and the
seeds showing that both dry ground and wetter areas were used for cereal growing and that the crops were probably sown in the spring.
suggest that the oats were spring sown but some barley and wheat was also grown and other weeds suggest this was sown in autumn. Oak leaves (above)
Oats (right)
(public domain images from Pixabay)
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Wales & West Utilities Pwllheli to Blaenau Ffestiniog Gas Pipeline
funded by Wales & West Utilities has meant that
gas infrastructure the project has enabled us
about our past.
Acknowledgements
Further Reading
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Wales & West Utilities Pwllheli to Blaenau Ffestiniog Gas Pipeline
Gwynedd Archaeological TrustYmddiriedolaeth Archaeolegol Gwynedd
Craig Beuno, Ffordd y Garth, Bangor, Gwynedd. LL57 2RT
Ffon: 01248 352535. Ffacs: 01248 370925. email:[email protected]