Pwllheli to Blaenau Ffestiniog Gas Pipeline

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

40 50 60

40 50 60 70

40

30

50

40

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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


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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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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


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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

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Betula

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-type

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M3-ii

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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)


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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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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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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)


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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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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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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Gwynedd Archaeological TrustYmddiriedolaeth Archaeolegol Gwynedd

Craig Beuno, Ffordd y Garth, Bangor, Gwynedd. LL57 2RT

Ffon: 01248 352535. Ffacs: 01248 370925. email:[email protected]

Pwllheli to Blaenau Ffestiniog Gas Pipeline

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