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

Mynydd Mallaen (SN 722 455) 

There has been a Significant Name Change that is retrospective to a hill 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 derived from a Trimble GeoXH 6000 survey conducted by Myrddyn Phillips and Aled Williams. 

Mynydd Mallaen (SN 722 455)

The criteria for the list that this retrospective 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; 500m Sub-Pedwarau, 500m Double Sub-Pedwarau, 400m Sub-Pedwarau, 390m Sub-Pedwarau and the 390m Double Sub-Pedwarau.  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

The hill is adjoined to the Mynydd Mallaen group of hills, which are situated in the central part of South Wales (Region B, Sub-Region B1), and it is positioned with a minor road to its north, and has the town of Llanwrtyd towards the 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 Crugiau Merched, with part of an accompanying note stating; aka Mynydd Mallaen.

Crugiau Merched

462m

SN722455

146/147

187

Marilyn. Clem/Yeaman. Trig pillar at 459m to the North. aka Mynydd Mallaen.

The two names of Crugiau Merched and Mynydd Mallaen are recorded on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map.  The former in italicised script indicating it applies to an ancient monument, in this instance the ancient cairns that are situated on the summit area of this hill, including one positioned adjacent to/at its summit, whilst the latter name applies to the mountain itself, which is extensive. 

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

Since the original publication of the Welsh P30 lists on Geoff Crowder’s v-g.me website there have been a number of 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 were 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, whilst others are current and digitally updated such as the interactive mapping on the Magic Maps and WalkLakes websites.  Two of the historic maps now available online are the Ordnance Survey Draft Surveyors map which formed the basis for the first publicly available Ordnance Survey One-Inch ‘Old Series’ map. 

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

The One-Inch ‘Old Series’ map was the first map that Ordnance Survey produced, and their publication culminated from the whole of Britain being surveyed between 1791 and 1874 and the detail gathered therein produced at a scale of one inch to the mile and published in sheet format between 1805 and 1874.  The One-Inch ‘Old Series’ maps for the whole of Wales are now available online; they are also available in map format as enlarged and re-projected versions to match the scale and dimensions of the Ordnance Survey 1:50,000 Landranger series and are published by Cassini.  This series of maps form another important part in the study of Welsh upland place-names and bridge the time-frame leading up to the production of the Ordnance Survey base map of the Six-Inch series.  And for an Ordnance Survey map, it is this map that gives a good portrayal of the extensive nature of land the name of Mynydd Mallaen applies to. 

Extract from the Ordnance Survey One-Inch 'Old Series' map

This list is now co-authored by Myrddyn Phillips and Aled Williams and when the 1^st edition of the list was published by Europeaklist in May 2013, the prioritised listed name was changed to Mynydd Mallaen, to reflect that this is the mountain name, in preference to the name recorded for the ancient cairns situated on its summit area.

Therefore, the name this hill is now listed by in the Y Pedwarau – The 400m Hills of Wales is Mynydd Mallaen, and this was derived from a variety of Ordnance Survey maps and confirmed via local enquiry.

 

The full details for the hill are: 

Group:  Mynydd Mallaen 

Name:  Mynydd Mallaen 

Previously Listed Name:  Crugiau Merched 

OS 1:50,000 map:  146, 147 

Summit Height:  460.9m (converted to OSGM15, Trimble GeoXH 6000) 

Summit Grid Reference:  SN 72217 45534 (Trimble GeoXH 6000) 

Bwlch Height:  259.2m (converted to OSGM15, Trimble GeoXH 6000) 

Bwlch Grid Reference:  SN 72372 46231 (Trimble GeoXH 6000) 

Drop:  201.7m (Trimble GeoXH 6000) 

 

Myrddyn Phillips and Aled Williams (December 2025) 

Mapping Mountains – Significant Name Changes – The Welsh P15s

 

Lan Tir Hen (SO 023 506) 

There has been a Significant Name Change to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Lan Tir Hen (SO 023 506)

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

The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10^th May 2019. 

The Welsh P15s 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 B, Sub-Region B1), and it is positioned with the A483 road to its north and a minor road to its south, and has the town of Llanfair-ym-Muallt (Builth Wells)  towards the east north-east.

When the listing that became known as The Welsh P15s was being compiled, this hill was listed under the point (Pt. 163m) notation, with an estimated c 16m of drop, based on the 163m summit spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map and an estimated c 147m bwlch height, based on interpolation of 10m contouring between 140m – 150m. 

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

As the summit of this hill comprises bounded land the details for it were examined on the Tithe map.  The term Tithe map is generally given to a map of a Welsh or English parish or township and which was prepared after the 1836 Tithe Commutation Act.  This act allowed tithes to be paid in cash rather than goods.  The Tithe maps gave names of owners and occupiers of land in each parish and importantly for place-name research they also included the name of enclosed land.  This enclosed land is usually based on a field system, however not every field is given a name, but many are and especially so in Wales. 

Extract from the Tithe map

The enclosed land where the summit of this hill is situated is given the number 440 on the Tithe map, this can be cross referenced against the apportionments; it is these apportionments that give the name of the owner or occupier of the land as well as the name of the land.  The land where the summit of this hill is situated is named Lan Tir Hen in the apportionments, with the details on the Tithe map appearing in the parish named as Llanynys and in the county named as Breconshire. 

Extract from the apportionments

Therefore, the name this hill is now listed by in the The Welsh P15s is Lan Tir Hen, and this was derived from the Tithe map. 

 

The full details for the hill are: 

Group:  Mynydd Epynt 

Name:  Lan Tir Hen 

Previously Listed Name:  Pt. 163m 

OS 1:50,000 map:  147

Summit Height:  163.7m (LIDAR)                                                           

Summit Grid Reference:  SO 02343 50631 (LIDAR)                                                  

Bwlch Height:  146.9m (LIDAR) 

Bwlch Grid Reference:  SO 02282 50522 (LIDAR) 

Drop:  16.8m (LIDAR) 

 

Myrddyn Phillips (December 2025)

Mapping Mountains – Significant Name Changes – 200m Twmpau

 

Moel Hiraddug (SJ 063 781) 

There has been a Significant Name Change to a hill that is listed in the 200m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Moel Hiraddug (SJ 063 781)

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

200m Twmpau – Welsh hills at or above 200m and below 300m in height that have 30m minimum drop, with an accompanying sub list entitled the 200m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 200m and below 300m in height with 20m or more and below 30m of drop.  The list is authored by Myrddyn Phillips, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

200m Twmpau by Myrddyn Phillips

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 minor roads to its north-east, west and south, and the A5151 road to its north, and has the village of Dyserth towards the north-west.

When the original 200m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was included in the main list under the transposed name of Y Foel, with an accompanying note stating; aka Mynydd Hiraddug.

Y Foel

265m

SJ063782

116

264/265

aka Mynydd Hiraddug

As both names are recorded by Ordnance Survey and as the summit of this hill comprises bounded land the details for it were examined on the Tithe map.  The term Tithe map is generally given to a map of a Welsh or English parish or township and which was prepared after the 1836 Tithe Commutation Act.  This act allowed tithes to be paid in cash rather than goods.  The Tithe maps gave names of owners and occupiers of land in each parish and importantly for place-name research they also included the name of enclosed land.  This enclosed land is usually based on a field system, however not every field is given a name, but many are and especially so in Wales.  The enclosed land where the summit of this hill is situated is named as Moel Hiraddug on the Tithe. 

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

Since the original publication of the Welsh P30 lists on Geoff Crowder’s v-g.me website, there have been a number of 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 were 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, whilst others are current and digitally updated such as the interactive mapping on the Magic Maps and WalkLakes websites, and it is the series of Ordnance Survey Six-Inch maps in conjunction with contemporary Ordnance Survey mapping and the Tithe map that form the basis in the prioritised listed name of this hill. 

Extract from the Tithe map

The Ordnance Survey series of Six-Inch maps formed the base map Ordnance Survey used for many decades leading to the production of the 1:10,000 Series of maps, both have now been superseded by the digitised Master Map.  The series of Six-Inch maps are excellent for name placement and especially so compared to the contemporary Ordnance Survey 1:25,000 Explorer map, and it is the series of Six-Inch maps that position the name of Moel Hiraddug adjacent to the summit of this hill.

Extract from the Ordnance Survey series of Six-Inch maps

Therefore, the name this hill is now listed by in the 200m Twmpau is Moel Hiraddug, and this was derived from the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map in conjunction with the Tithe map and the Ordnance Survey series of Six-Inch maps. 

 

The full details for the hill are:

Group:  Moel y Gamelin

Name:  Moel Hiraddug

Previously Listed Name:  Y Foel   

OS 1:50,000 map:  116

Summit Height:  264.4m (LIDAR) 

Summit Grid Reference:  SJ 06369 78199 (LIDAR) 

Bwlch Height:  186.0m (LIDAR) 

Bwlch Grid Reference:  SJ 06724 77888 & SJ 06727 77887 & SJ 06731 77883 & SJ 06736 77881 (LIDAR) 

Drop:  78.5m (LIDAR) 

 

Myrddyn Phillips (December 2025)                 

Mapping Mountains – Significant Height Revisions – The Fours – The 400m Hills of England

 

Gib Torr Rocks (SK 018 647) 

There has been a Significant Height Revision to a hill that is listed in the The Fours – The 400m Hills of England, with the summit height, col height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Gib Torr Rocks (SK 018 647)

The criteria for the list that this height revision applies to are:

The Fours – The 400m Hills of England - English hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main list is a sub list entitled the Sub-Fours, the criteria for which are all English hills at or above 400m and below 500m in height that have 15m or more and below 30m of drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and is available to download in Google Doc format from the Mapping Mountains site.

The Fours - The 400m Hills of England by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Gib Torr Rocks, and it is adjoined to the Axe Edge group of hills, which are situated in the Peak District, and it is positioned with minor roads to its north, west, south and east, and the A53 road to its south-east, and has the town of Leek towards the south south-west.

When the Introduction to the first group of hills for the updated and revised listing of the The Fours – The 400m Hills of England was published by Mapping Mountains on the 10^th September 2022, it was announced that the accompanying sub lists were being revised with the two 390m categories dispensed with and the criteria and name of the 400m Sub-Fours revised.  The one accompanying sub list is now named the Sub-Fours with its criteria being all English hills 400m and above and below 500m in height that have 15m and more and below 30m of drop.

Prior to this revision this hill was listed with an estimated c 17m of drop, based on an estimated c 415m summit height and an estimated c 398m col height, with both heights based on interpolation of 5m contouring that appears on the Ordnance Survey 1:25,000 Explorer map. 

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

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

LIDAR summit image of Gib Torr Rocks (SK 018 647)

LIDAR analysis gives the summit height of this hill as 417.3m and when compared to its originally listed height this comes within the parameters of the Significant Height Revisions used within this page heading, these parameters are:

The term Significant Height Revisions applies to any listed hill whose interpolated height and Ordnance Survey, Harvey or other interactive map summit spot height has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or analysis of data produced via LIDAR.  Also included are hills whose summit map data is missing an uppermost ring contour when compared with the data produced by the Trimble or by LIDAR analysis.

Therefore, the new listed summit height of this hill is 417.3m and this was derived from LIDAR analysis, this is 2.3m higher than the originally listed summit height, which was based on interpolation of the uppermost ring contour that appears on the Ordnance Survey 1:25,000 Explorer map. 

 

The full details for the hill are:

Group:  Axe Edge

Name:  Gib Torr Rocks

OS 1:50,000 map:  119

Summit Height (New Height):  417.3m (LIDAR)

Summit Grid Reference:  SK 01803 64749 (LIDAR)

Col Height:  398.5m (LIDAR)

Col Grid Reference:  SK 01797 64842 (LIDAR)

Drop:  18.8m (LIDAR)

 

Myrddyn Phillips and Aled Williams (December 2025)