Mapping Mountains – Significant Name Changes – 100m Twmpau

Pen Twyn Wood (SO 415 147)

There has been a Significant Name Change to a hill that is listed in the 100m Twmpau, with the summit height, bwlch height, their locations, the drop and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Pen Twyn Wood (SO 415 147)

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height with 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 hill is adjoined to the Mynyddoedd Duon group of hills which are situated in the eastern part of South Wales (Region C, Sub-Region C3), and it is positioned with the Afon Troddi (River Trothy) and the B4233 road to its north and minor roads to its south-west, south and south-east, and has the town of Y Fenni (Abergavenny) towards the west and Trefynwy (Monmouth) towards the east south-east.

The hill originally appeared in the 100m P30 list on Geoff Crowder’s v-g.me website under a partly invented name of Pen-twyn Wood Top, with an accompanying note stating; Name from wood to the West. 

Pen-twyn Wood Top

105m

SO415148

161

14

Name from wood to the West

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 use the name of a wood and add the word Top 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

Since publication of these P30 lists on Geoff Crowder’s v-g.me website there have been a number of Ordnance Survey 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 are current and digitally updated such as the Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map, and it is the contemporary Ordnance Survey 1:25,000 Explorer map that uses the name of Pen Twyn Wood, with the series of Six-Inch maps confirming this name’s placement.

Extract from the Ordnance Survey series of Six-Inch maps

Therefore, the name this hill is now listed by in the 100m Twmpau is Pen Twyn Wood, and this was derived from contemporary Ordnance Survey 1:25,000 Explorer maps, with its position in relation to this hill confirmed via the Ordnance Survey series of Six-Inch maps.

The full details for the hill are:

Group:  Mynyddoedd Duon

Name:  Pen Twyn Wood

Previously Listed Name:  Pen-twyn Wood Top

OS 1:50,000 map:  161

Summit Height:  104.9m (LIDAR)

Summit Grid Reference:  SO 41529 14797 (LIDAR)

Bwlch Height:  72.3m (LIDAR)

Bwlch Grid Reference:  SO 41867 14464 (LIDAR) 

Drop:  32.6m (LIDAR)

Myrddyn Phillips (February 2020)