Mapping Mountains – Significant Name Changes – 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales

Plas Gwyn (SH 524 817)

There has been a Significant Name Change to a hill that is listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, its location, the drop and status of the hill confirmed by LIDAR analysis, and a subsequent summit survey with the Trimble GeoXH 6000 conducted by Myrddyn Phillips, with the latter taking place on the 22^nd October 2018.

Plas Gwyn (SH 524 817)

The criteria for the two listings that this name change applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

Y Trechol - The Dominant Hills of Wales - Welsh P30 hills whose prominence  equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height, with the Introduction to the Mapping Mountains publication of this list appearing on the 3^rd December 2015.

The hill is adjoined to the Ynys Môn group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it has the A5025 road to its west and the coast to its north and east, and overlooks Traeth-coch (Red Wharf Bay) to its south-east, and has the village of Benllech towards its north-west.

This hill was first listed in the original Welsh 30-99m P30 list published on Geoff Crowder’s v-g.me website, under the partly transposed and invented name of Moel Castell Mawr, with an accompanying note stating; Name from remains of castle to the South-East.

Moel Castell Mawr

78m

SH526817

114/115

263

Name from remains of castle to the South-East

During my early hill listing I thought it appropriate to either invent a name for a hill, or use a name that appeared near to the summit of the hill on Ordnance Survey maps of the day.  My preference was to use farm names and put Pen, Bryn or Moel in front of them or as in this instance transpose the name of what I presumed to be a castle and prefix it with the word Moel.  This is not a practice that I now advocate as with time and inclination place-name data can be improved either by asking local people or by examining historic documents, through this form of research an appropriate name for the hill can usually be found.

The Trimble GeoXH 6000 gathering data at the summit of Plas Gwyn

After visiting this hill I called at the Plas Gwyn Caravan and Camping Park which is situated just below the hill to the south and met David Bennet who explained that the land taking in this hill is owned by Michael Buckley, David kindly directed me to Michael’s home, which I called out twice over the following few days without any reply.  However, on my first visit I met Mark Griffith who was trimming a hedge and he kindly gave me a contact telephone number for Michael.  When I contacted Michael he explained that the hill has been owned by his family for many years and that it is known after that of the farm, Plas Gwyn. 

Therefore, the name this hill is now listed by in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales is Plas Gwyn, and this was derived from local enquiry.

The full details for the hill are:

Group:  Ynys Môn

Name:  Plas Gwyn

Previously Listed Name:  Moel Castell Mawr 

OS 1:50,000 map:  114, 115

Summit Height:  76.1m (converted to OSGM15)

Summit Grid Reference:  SH 52494 81743

Bwlch Height:  41.9m (LIDAR)

Bwlch Grid Reference:  SH 52209 81404 (LIDAR)

 

Drop:  34.2m (Trimble summit and LIDAR bwlch)

Dominance:  44.91% (Trimble summit and LIDAR bwlch)

For details on the summit survey of this hill

Myrddyn Phillips (May 2019)