Foel
Cedig – Relocation of Marilyn, Hump, Simm, Hewitt, Pellennig, Uchaf and Nuttall
summit from Cyrniau Nod
UKHillwalking
Article
UKHillwalking recently published an article on the summit
relocation of Cyrniau Nod to Foel Cedig.
The original article and a link to it on the UKHillwalking website
appear below.
Moving Mountain Summits
Prolific amateur hill surveyor Myrddyn
Phillips 'discovers' a new summit for one of the Berwyn mountains of North
Wales...
Foel Cedig stands out from afar as it has a small
grassy knoll which gives the hill the impression of having a slightly raised
summit - a contrast to its heather bound neighbours, the majority of which
comprise high whale backed ridges that have rounded summits almost
indistinguishable from the moor. However, the hill was thought to have little
prominence as it is given a map height of 666m, whilst the neighbouring Cyrniau
Nod has always been accepted as higher because of its 667m map height.
 |
| Foel Cedig on left with the deposed Cyrniau Nod on the right |
These two hills, Foel Cedig
and Cyrniau Nod, form a part of the great swathe of wild land that comprise the
Berwyn. This extensive range of hills stretches from the Afon Dyfrdwy (River
Dee) as it passes the confines of Corwen and Llangollen in the north, all the
way south to the hills above Dinas Mawddwy and the infant Afon Dyfi (River
Dovey).
As Cyrniau Nod is higher
according to Ordnance Survey maps it has always been considered the prioritised
summit of these two hills, and with a prominence of 179m and a height over 600m
it is both relatively high and relatively prominent. As such it is listed as a
Marilyn, Hump, Simm, Hewitt, Uchaf and Nuttall:
- Marilyn:
British hills with 150m minimum drop irrespective of their height
- Hump: British
hills with 100m minimum drop irrespective of their height
- Simm: British
hills with 600m minimum height and 30m minimum drop
- Hewitt:
English, Welsh and Irish hills with 2,000ft (609.6m) minimum height and
30m minimum drop
- Uchaf: This is
the working title for a list comprising Welsh hills with 500m minimum
height and 15m minimum drop
- Nuttall: English and Welsh hills with 2,000ft (609.6m) minimum height and 15m minimum drop
However, the surveying method of photogrammetry that ascertained the map height of Foel Cedig has a margin of uncertainly of +/- 3m, whilst the map height given Cyrniau Nod is based on a series of levelled heights which are more accurate. So could Foel Cedig in fact be higher than Cyrniau Nod? There was only one way to find out; visit both hills and accurately survey their summits.
It was a breezy morning
setting off from the high road at it passes over the upper part of Cwm Hirnant
to the west of these hills, and with heavy overnight rain and a forecast of
morning showers I did not want to linger.
A track skirting the summits
of a number of heather bound hills eases access, and I used this to make forays
to each as I slowly made surveying progress to the prioritised surveys of Foel
Cedig and Cyrniau Nod.
To survey these hills I used
a Trimble GeoXH 6000 which is a GNSS receiver capable of measurement to within
and better than 0.1m in height. As it has an internal antenna and only weighs
2lb it does not require an additional antenna, pole and tripod, therefore its
portability and its accuracy over a five minute period of data collection are
huge advantages when out on the hill.
 |
| The track across the moor leading toward Foel Cedig |
The summit of Foel Cedig
comprises an attractive knoll with exposed rock and is easily distinguished
from surrounding ground. To give the Trimble elevation above its immediate
surrounds I usually place the equipment on top of my rucksack, using this as an
improvised tripod, and this is what I did for each summit.
Having taken a ten minute
data set I continued through the heather and bog toward Cyrniau Nod. John
Barnard and I had surveyed this hill with a level and staff for summit position
in June 2014, and once at its summit this is where I placed the Trimble and
gathered another ten minute data set. So what of the results?
The Trimble GeoXH 6000
results are given below:
- Foel Cedig –
667.4m summit at SH 98170 28327
- Cyrniau Nod – 666.2m summit at SH 98847 27920
Therefore, as Foel Cedig is 1.2m higher than Cyrniau Nod, the prioritised summit is relocated to the attractive rock exposed knoll of Foel Cedig.
This information may be met
with gasps of woe by any hill walker who has visited this area to bag either a
Marilyn, Uchaf or Nuttall, as except for those who purposely diverted to visit
Foel Cedig with the understanding that its map height has such a margin of
uncertainty, the summit would no doubt have been bypassed.
Alan Dawson, the author of
the Marilyns, Hewitts and Simms has been informed of this result and accepted
the summit relocation, as have the authors of the Uchafion list, Aled Williams
and Myrddyn Phillips (that's me!); will John and Anne Nuttall follow suit?
We'll have to wait and see.
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