Mapping Mountains – Significant Name Changes – Y Pedwarau – The 400m Hills of Wales

Pen Carn Llwyd (SO 244 125)

There has been a Significant Name Change to a hill that is listed in the Y Pedwarau – The 400m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed via LIDAR analysis conducted by Aled Williams.

LIDAR image of Pen Carn Llwyd (SO 244 125)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being listed in the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh hills at or above 400m and below 500m in height that have 20m or more and below 30m of drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and is published on Mapping Mountains in Google Doc format.

The hill is adjoined to the Cymoedd Gwent group of hills, which are situated in the north-eastern part of South Wales (Region C, Sub-Region C2), and it is positioned with the A465 road to its north and the B4246 road to its east, and has the town of Y Fenni (Abergavenny) towards the east north-east.

The hill appeared in the original Welsh 400m P30 list published on Geoff Crowder’s v-g.me website under the name of Gilwern Hill, which is a prominent name that appears to the north-west of this hill’s summit on contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps.  This is also the name the hill was listed by in the 1^st edition of the Y Pedwarau published by Europeaklist in May 2013.

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

Since publication of the 1^st edition of Y Pedwarau there are now 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.  One of the historic maps now available 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 this map that formed the basis for the change in this hill’s listed name.

Extract from the Ordnance Survey Draft Surveyors map

The Draft Surveyors maps consist of the preliminary drawings made by the Ordnance Surveyor’s 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 the Draft Surveyors map that name the hill as Pen Carn Llwyd.

Therefore, the name this hill is now listed by in the Y Pedwarau – The 400m Hills of Wales is Pen Carn Llwyd, and this was derived from the Ordnance Survey Draft Surveyors map.

The full details for the hill are:

Group:  Cymoedd Gwent

Name:  Pen Carn Llwyd

Previously Listed Name:  Gilwern Hill

OS 1:50,000 map:  161

Summit Height:  441.6m (LIDAR)

Summit Grid Reference:  SO 24427 12563 (LIDAR)

Bwlch Height:  416.3m (LIDAR)

Bwlch Grid Reference:  SO 24363 11890 (LIDAR)

Drop:  25.3m (LIDAR)

Myrddyn Phillips and Aled Williams (January 2020)