Mapping Mountains - Summit Relocations – The 500-Metre Tops of England and Wales – Deweys

 

Foel Fawr (SH 728 392) 

There has been a Summit Relocation that is retrospective to a hill that is listed in the The 500-Metre Tops of England and Wales, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by a Trimble GeoXH 6000 survey conducted by Myrddyn Phillips and Aled Williams on the 19^th July 2020.

Foel Fawr (SH 728 392)

The criteria for the list that this summit relocation applies to are:

The 500-Metre Tops of England and Wales are affectionately known after their hill list compiler; Michael Dewey.  This list mixes metric and imperial height in its criteria to bookend up to the 2000ft height band and takes in all hills in England, Isle of Man and Wales that are 500m and above and below 2000ft (609.6m) in height that have 30m minimum drop. 

Mountain tables by Michael Dewey

Michael Dewey died on the 5^th November 2022.  His wife; Gillian wished for this list to be carried on and made provision for it to be co-authored by Myrddyn Phillips.  Michael will always be the compiler and originator, it’s just that he’s now got a co-author to safeguard this list and carry this list on.

The name the hill is listed by is Foel Fawr and it is adjoined to the Arenig Fach group of hills, which are situated in the central part of North Wales, and it is positioned with the B4391 road to its north, the A470 road to its west and the A4212 road to its south, and has the village of Trawsfynydd towards the south-west.

When the original list of Deweys appeared in the Mountain tables book published by Constable in 1995, this hill was listed with a 528m summit height positioned at SH 726 395, based on the spot height that appears on the Ordnance Survey 1:25,000 Explorer map.

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

Since the original compilation of this list 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 Ordnance Survey Vector Map Local that was hosted on the Geograph website and which was entitled the Interactive Coverage Map, and it was this map that showed a 528m map heighted twin summit positioned at SH 728 392.  The two 528m spot heights are also shown on the mapping hosted on the Magic Maps website. 

Extract from the Magic Maps website

However, it was not until the survey with the Trimble GeoXH 6000 that the details for this hill could be accurately re-assessed.  The height and position for each summit is given below: 

 

South-easterly summit:  528.611m at SH 72872 39284 

North-westerly summit:  527.542m at SH 72621 39476 

 

The above detail compared to the original summit position comes within the parameters of the Summit Relocations used within this page heading, these parameters are: 

The term Summit Relocations applies when the high point of the hill is found to be positioned; in a different field, to a different feature such as in a conifer plantation,  within a different map contour either on Ordnance Survey maps or interactive mapping, to a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is considered a relatively recent man-made construct, or the listing of a new twin summit or de-twinning of a summit, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist. 

The Trimble GeoXH 6000 gathering data at the higher of the Foel Fawr summits

The Trimble GeoXH 6000 gathering data at the lower of the Foel Fawr summits

Therefore, the summit height produced by the Trimble GeoXH 6000 survey is 528.6m and this is positioned at SH 72872 39284, this position is not given a spot height on contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps, but is given a 528m spot height on the mapping hosted on the Magic Maps website, and is approximately 260 metres south-eastward from where the original listed summit is positioned. 

 

The full details for the hill are:

Group:  Arenig Fach

Name:  Foel Fawr

OS 1:50,000 map:  124

Summit Height:  528.6m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference (New Position):  SH 72872 39284 (Trimble GeoXH 6000)  

Bwlch Height:  485.5m (converted to OSGM15, Trimble GeoXH 6000)

Bwlch Grid Reference:  SH 73074 39525 (Trimble GeoXH 6000)

Drop:  43.1m (Trimble GeoXH 6000 summit and bwlch)

 

Myrddyn Phillips (May 2026)