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

Great Trefgarn Mountain (SM 944 243) 

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 Great Trefgarn Mountain (SM 944 243)

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. 

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 Garn Fawr group of hills, which are situated in the south-western part of South Wales (Region B, Sub-Region B1), and it is positioned with minor roads to its north and south, the B4330 road to its west and the A40 road to its east, and has the town of Hwlffordd (Haverfordwest) towards the south.

The hill appeared in the original Welsh 100m P30 list on Geoff Crowder’s v-g.me website, under the transposed name of Great Treffgarne Mountain, which is the composition of a prominent name that appears close to the summit of this hill on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map. 

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

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 and where this is substantiated by either historic documentation and/or contemporary usage should be prioritised in favour of a contemporary anglicised or English version of the name.  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.

Since the original publication of the Welsh P30 lists on Geoff Crowder’s v-g.me website a number of place-name books have been accessed to either find or substantiate locally known and/or historic names for hills.  One of the books accessed is the Dictionary of the Place-Names of Wales, published in 2007 by Gomer Press and researched and written by Hywel Wyn Owen and Richard Morgan.  It is this book that documents the preferred composition of the middle word of the listed name of this hill as Trefgarn, noting; A common local alternative, under English influence, is Treffgarn (e).

Therefore, the name this hill is now listed by in the 100m Twmpau and Y Trechol – The Dominant Hills of Wales is Great Trefgarn Mountain, and although a fully Welsh name has not been found by the author for this hill the preferred Welsh composition of Trefgarn is favoured, and this is documented in the Dictionary of the Place-Names of Wales book. 

 

The full details for the hill are:

Group:  Garn Fawr

Name:  Great Trefgarn Mountain

Previously Listed Name:  Great Treffgarne Mountain 

OS 1:50,000 map:  157, 158

Summit Height:  165.2m (LIDAR) 

Summit Grid Reference:  SM 94454 24305 (LIDAR) 

Bwlch Height:  97.1m (LIDAR) 

Bwlch Grid Reference:  SM 93483 23607 (LIDAR) 

Drop:  68.1m (LIDAR) 

Dominance:  41.22% (LIDAR) 

 

Myrddyn Phillips (June 2024)