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

Clogau (SJ 184 462)

There has been a Significant Name Change to a hill that is now 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 estimated from contour interpolation using the 5m contours on the OS Maps website.

Clogau (SJ 184 462)

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 added to 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 Moel y Gamelin group of hills, which are situated in the north-eastern part of North Wales (Region A, Sub-Region A2), and it is positioned with the A542 road to its north-east, the A5104 road to its north-west and the A5 road to its south, and has the town of Llangollen towards the south-east.

When the original 400m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website this hill was not included in the Hills to be surveyed sub list that accompanied the main P30 list, as it did not meet the criteria then used in this sub category.

The sub list was standardised and interpolated heights and drop values also included, but it was only when compiling The Welsh P15s that this hill was listed with 17m of drop based on the 455m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and the 438m spot height that appears in the vicinity of this hill’s bwlch on the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map, and therefore this hill was not included 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

The hill was originally listed in The Welsh P15s by the name of Berwyn Quarry, which is a name that appears adjacent to this hill’s summit on the contemporary Ordnance Survey 1:25,000 Explorer map.

Since publication of the 1^st edition of Y Pedwarau 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.  Two of the historic maps now available are 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 series of Ordnance Survey Six-Inch maps that form the basis for the change in this hill’s listed name.

Extract from the series of Ordnance Survey Six-Inch maps

Therefore, the name this hill is now listed by in the Y Pedwarau – The 400m Hills of Wales is Clogau and this was derived from the series of Ordnance Survey Six-Inch maps, with the Welsh name for the quarry being prioritised over the English name which for listing purposes is standard practice.

The full details for the hill are:

Group:  Moel y Gamelin

Name:  Clogau

Previously Listed Name:  Berwyn Quarry

OS 1:50,000 map:  116

Summit Height:  c 460m (interpolation)

Summit Grid Reference:  SJ 18455 46229 (interpolation)

Bwlch Height:  c 439m (interpolation)

Bwlch Grid Reference:  SJ 18304 46343 (interpolation)

Drop:  c 21m

Myrddyn Phillips and Aled Williams (December 2019)