Mapping Mountains – Significant Name Changes – 200m Twmpau and Y Trechol – The Dominant Hills of Wales

 

Banc Bryn Amlwg (SN 547 504) 

There has been a Significant Name Change to a hill that is listed in the 200m 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 Banc Bryn Amlwg (SN 547 504)

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

200m Twmpau – Welsh hills at or above 200m and below 300m in height that have 30m minimum drop, with an accompanying sub list entitled the 200m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 200m and below 300m 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 200m 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 Bach group of hills, which are situated in the western part of South Wales (Region B, Sub-Region B1), and it is positioned with a minor road to its west and the A482 road to its north-east, and has the town of Llanbedr Pont Steffan (Lampeter) towards the south-east.

The hill appeared in the original Welsh 200m P30 list on Geoff Crowder’s v-g.me website, under the transposed name of Allt Maestir, which is a prominent name that appears to the west of the summit of this hill on the Ordnance Survey 1:25,000 Explorer map.

Allt Maestir

278m

SN547505

146

199

Clem/Yeaman. Trig pillar.

 

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 a name that appears on the contemporary Ordnance Survey 1:25,000 Explorer map and which does not necessarily apply to land where the summit is situated, and use it for that of the hill.  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

Since the original publication of the Welsh P30 lists on Geoff Crowder’s v-g.me website there have been a number of maps made available online.  Some of these are historic such as the series of Six-Inch maps on the National Library of Scotland website.  Whilst others were digitally updated such as the Ordnance Survey Vector Map Local that was hosted on the Geograph website and which was entitled the Interactive Coverage Map, whilst others are current and digitally updated such as the interactive mapping on the Magic Maps and WalkLakes websites.  One of the historic maps now available online is the Ordnance Survey Draft Surveyors map which formed the basis for the first publicly available Ordnance Survey One-Inch ‘Old Series’ map, and it is the Draft Surveyors map in combination with the Six-Inch map that has prompted the change in the listed name of this hill.

The Draft Surveyors maps consist of the preliminary drawings made by the Ordnance Survey surveyors between the 1780s and 1840 and formed the basis for the first publicly available One-Inch map.  They were drawn at scales of six inches to the mile for areas considered of particular military significance and down to two inches to the mile for other areas.  Fair copies were then produced from these preliminary drawings to one inch to the mile and then copper plates were prepared for printing.  The Draft Surveyors maps for the whole of Wales are now available online and they form an important part in the study of Welsh upland place-names as they bridge the time frame between the late 18^th century and the mid-19^th century when the Ordnance Survey produced their first One-Inch maps, and importantly for this hill and its listed name, it is this map that uses the name of Brynamlwg Bank, with it being listed as Banc Bryn Amlwg. 

Extract from the Ordnance Survey Draft Surveyors Map

The Ordnance Survey series of Six-Inch maps formed the base map Ordnance Survey used for many decades leading to the production of the 1:10,000 Series of maps, both have now been superseded by the digitised Master Map.  The series of Six-Inch maps are excellent for name placement and especially so compared to the contemporary Ordnance Survey 1:25,000 Explorer map, and it is the series of Six-Inch maps that places the land incorporating Allt y Maestir taking in the forested section of this hill and not where LIDAR places the summit of the hill. 

Extract from the Ordnance Survey series of Six-Inch maps

Therefore, the name this hill is now listed by in the 200m Twmpau and Y Trechol – The Dominant Hills of Wales is Banc Bryn Amlwg, and this was derived from the Ordnance Survey Draft Surveyors Map, with the land incorporating Allt y Maestir substantiated from the Ordnance Survey series of Six-Inch maps. 

 

The full details for the hill are:

Group:  Mynydd Bach

Name:  Banc Bryn Amlwg

Previously Listed Name:  Allt Maestir   

OS 1:50,000 map:  146

Summit Height:  277.7m (LIDAR) 

Summit Grid Reference:  SN 54729 50489 (LIDAR) 

Bwlch Height:  175.65m (LIDAR) 

Bwlch Grid Reference:  SN 52826 53160 (LIDAR) 

Drop:  102.0m (LIDAR) 

Dominance:  36.74% (LIDAR)

 

Myrddyn Phillips (November 2022)