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

Pt. 118.9m (SN 710 294) 

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 Pt. 118.9m (SN 710 294)

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 Mynydd Du group of hills, which are situated in the southern part of South Wales (Region B, Sub-Region B5), and it is positioned with the Afon Tywi (River Towy) and the A40 road to its west, the B4069 road to its east, and has the village of Llangadog towards the south.

The hill appeared in the original Welsh 100m P30 list on Geoff Crowder’s v-g.me website, under the invented and transposed name of Allt y Tyddyn, with an accompanying note stating; Name from farm to the North.

Allt y Tyddyn

119m

SN711294

146/160

12

Name from farm to the North

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 a farm and add the words Allt y to it.  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. 

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

However, on occasion even when research is conducted an appropriate name for the hill may not be found, and on such occasions the listing protocol is to use the point (Pt. 118.9m) notation, and for this hill this is such an example.

Therefore, the name this hill is now listed by in the 100m Twmpau and Y Trechol – The Dominant Hills of Wales is Pt. 118.9m, and this is being used as the author has not found an appropriate name for the hill either through historic research and/or local enquiry. 

 

The full details for the hill are:

Group:  Mynydd Du

Name:  Pt. 118.9m

Previously Listed Name:  Allt y Tyddyn 

OS 1:50,000 map:  146, 160

Summit Height:  118.9m (LIDAR) 

Summit Grid Reference:  SN 71046 29411 (LIDAR) 

Bwlch Height:  69.9m (LIDAR) 

Bwlch Grid Reference:  SN 72466 30393 (LIDAR) 

Drop:  48.9m (LIDAR) 

Dominance:  41.16% (LIDAR) 

 

Myrddyn Phillips (April 2024)