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

Mynydd Epynt (SN 961 464)

There has been a Significant Name Change to a hill that is listed in the Y Pedwarau - The 400m Hills of Wales and the 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 a Trimble GeoXH 6000 summit survey and LIDAR bwlch analysis conducted by Myrddyn Phillips.  With the change in the listed summit height initiated by LIDAR analysis conducted by Aled Williams.

Mynydd Epynt (SN 961 464)

The criteria for the two listings 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 list are five categories of sub hills, with this hill being included in the 400m Sub-Pedwar category.  The criteria for this sub category 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.

Y Pedwarau - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

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 Epynt group of hills, which are situated in the central part of South Wales (Region C2, Sub-Region C2A), and it is positioned with the B4519 road to its north-east, and has the town of Llanfair-ym-Muallt (Builth Wells) towards the north-east.

The hill appeared in the original Welsh 400m P30 list compiled by Myrddyn Phillips and published on Geoff Crowder’s v-g.me website, under the transposed name of Mynydd Epynt, which is a prominent name that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map.

Extract from the Ordnance Survey 1:50,000 Landranger map

The hill was listed in the 1^st edition of the Y Pedwarau published by Europeaklist in May 2013 under the name of Clepyn Melyn, with an accompanying symbol designating that this name was sourced from local enquiry.

The name Clepyn Melyn applies to a patch of land near to the summit of this hill, and as such this name was used for that of the hill as it was considered its main named feature.  However, since publication of the 1^st edition of Y Pedwarau by Europeaklist a number of names have been under review, including this one, and as the summit of this hill is the highest part of the entire mountain known as Mynydd Epynt this name is now preferred to that previously used.

Therefore, the name this hill is now listed by in the Y Pedwarau – The 400m Hills of Wales and the Y Trechol – The Dominant Hills of Wales is Mynydd Epynt, and this was derived from the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map.

The full details for the hill are:

Group:  Mynydd Epynt

Name:  Mynydd Epynt

Previously Listed Name:  Clepyn Melyn

OS 1:50,000 map:  147

Summit Height:  475.7m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SN 96124 46428 (Trimble GeoXH 6000)  

Bwlch Height:  277.9m (LIDAR)

Bwlch Grid Reference:  SN 84054 43300 (LIDAR) 

Drop:  197.8m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  41.58% (Trimble GeoXH 6000 summit and LIDAR bwlch)

Myrddyn Phillips and Aled Williams (January 2020)