Mapping Mountains – Significant Name Changes – Y Trichant – The 300m Hills of Wales and Y Trechol – The Dominant Hills of Wales

 

Allt yr Hebog (SN 686 444) 

There has been a Significant Name Change to a hill that is listed in the Y Trichant – The 300m Hills of Wales 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 Allt yr Hebog (SN 686 444)

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

Y Trichant – The 300m Hills of Wales.  Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13^th May 2017. 

Y Trichant - The 300m Hills of Wales 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 which 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 Esgair Wen group of hills, which are situated in the central part of the South Wales Region (Region B, Sub-Region B1), and it is positioned with minor roads to its north-west, west, south and east, and the A482 road farther to its south-west, and has the small community of Cwrtycadno towards the east south-east. 

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

When the original 300m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was listed under the transposed name of Pen Allt-yr-hebog, with an accompanying note stating; aka Allt yr Hebog.  With both of these names appearing near the summit of this hill on the contemporary Ordnance Survey 1:25,000 Explorer map, with the presumption being that the old prioritised name applied to the summit and the non-prioritised name applied to the hill.

Pen Allt-yr-hebog

342m

SN686445

146

187/199

Clem/Yeaman. aka Allt yr Hebog

 

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 old Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map, and the interactive mapping on the Magic Maps and WalkLakes websites, and it is the Ordnance Survey series of Six-Inch maps that give the name of Allt yr Hebog in larger font compared to that of Pen Allt-yr-hebog, with one denoting the hill and the other the summit. 

Extract from the Ordnance Survey series of Six-Inch maps

Therefore, the name this hill is now listed by in the Y Trichant – The 300m Hills of Wales and Y Trechol – The Dominant Hills of Wales is Allt yr Hebog and this was derived from the Ordnance Survey 1:25,000 Explorer map with the name of the hill now prioritised over that of its summit name, with this substantiated by the Ordnance Survey series of Six-Inch maps. 

 

The full details for the hill are: 

Group:  Esgair Wen 

Name:  Allt yr Hebog 

Previously Listed Name:  Pen Allt-yr-hebog 

OS 1:50,000 map:  146

Summit Height:  342.2m (LIDAR)                                                           

Summit Grid Reference:  SN 68644 44484 (LIDAR) 

Bwlch Height:  203.3m (LIDAR) 

Bwlch Grid Reference:  SN 68906 44865 (LIDAR) 

Drop:  139.0m (LIDAR) 

Dominance:  40.60% (LIDAR) 

 

Myrddyn Phillips (November 2021)