Mapping Mountains – Significant Name Changes – 100m Twmpau and Y Trechol – The Dominant Hills of Wales

Castell Dinefwr (SN 611 217) 

There has been a Significant Name Change to a hill that is listed in the 100m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, bwlch height and their locations, the drop, dominance and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Castell Dinefwr (SN 611 217)

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

100m Twmpau – Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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. 

The 100m Twmpau by Myrddyn Phillips

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.  The list is authored by Myrddyn Phillips with the Introduction to the start of the Mapping Mountains publication of this list appearing on the 3^rd December 2015, and the list is now available in its entirety on Mapping Mountains in Google Doc format. 

Y Trechol - The Dominant Hills of Wales by Myrddyn Phillips

The hill is adjoined to the Mynydd Mallaen group of hills, which are situated in the central part of South Wales (Region B, Sub-Region B1), and it is positioned with the A40 road to its north, the Afon Tywi to its south and the A483 road to its east, and has the town of Llandeilo towards the east north-east.

Extract from the Ordnance Survey 1:25,000 Explorer map

The hill appeared in the original Welsh 100m P30 list on Geoff Crowder’s v-g.me website, under the name of Dynevor Castle, with an accompanying note stating; Name from ancient castle at the summit.

Dynevor Castle

100m

SN612217

159

186

Name from ancient castle at the summit

 

The intricacies of language and prioritising one in favour of another for listing a hill is fraught with complication, with originating Cymraeg names being anglicised and also originating English names being cymricised, examples such as these are more common in border country and especially so for anglicised forms.  There is no steadfast rule that fits all, but as a standard a name that has its origins in the Welsh language should be prioritised in favour of a contemporary anglicised or English version of the name, and ideally for this to be substantiated by either historic documentation and/or contemporary usage.  Likewise, if a name exists where an element of it is in English and if this name applies to a hill that is situated in a Welsh speaking part of Wales it is standard practice to use a full Welsh term for the name.  It is also standard practice to use a Welsh name for a hill if another name exists that has originated in a different language.

Therefore, the name this hill is now listed by in the 100m Twmpau and Y Trechol – The Dominant Hills of Wales is Castell Dinefwr, and this name is used as it is the Welsh name for the castle which is positioned on the summit of this hill. 

The full details for the hill are:

Group:  Mynydd Mallaen

Name:  Castell Dinefwr

Previously Listed Name:  Dynevor Castle   

OS 1:50,000 map:  159

Summit Height:  101.1m (LIDAR) 

Summit Grid Reference:  SN 61167 21730 (LIDAR) 

Bwlch Height:  49.0m (LIDAR) 

Bwlch Grid Reference:  SN 61568 21996 (LIDAR) 

Drop:  52.1m (LIDAR) 

Dominance:  51.54% (LIDAR) 

 

Myrddyn Phillips (April 2022)