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

 

Pt. 464.7m (SO 041 681) 

There has been a Significant Name Change with the details being retrospective to a hill that is 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 LIDAR analysis initially conducted by Aled Williams and subsequently by Myrddyn Phillips. 

LIDAR image of Pt. 464.7m (SO 041 681)

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 Hirddywel group of hills, which are situated in the northern part of South Wales (Region B, Sub-Region B2), and it is positioned with minor roads to its west and south-east, and the A44 road to its south-west, and has the town of Rhaeadr Gwy (Rhayader) towards the west.

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 invented and transposed name of Pen yr Onnen, with an accompanying note stating; Name from buildings to the North-West.

Pen yr Onnen

465m

SO042682

136/147

200

Name from buildings to the North-West

When Myrddyn Phillips first compiled this list he thought it appropriate to either invent a name for a hill, or use a name that appeared near to the summit of the hill on Ordnance Survey maps of the day.  His preference was to use farm names and put Pen, Bryn or Moel in front of them.  This is not a practice that he now advocates as with time and inclination place-name data can be improved either by asking local people or by examining historic documents, through this form of research an appropriate name for the hill can usually be found. 

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

However, on occasion even when research is conducted an appropriate name for the hill may not be found, and on such occasions the listing protocol is to use the point notation, and this is the protocol adopted when Myrddyn Phillips and Aled Williams became co-authors of this list and the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013.  This hill was then listed under the point (Pt. 465m) notation with an estimated c 38m of drop, based on the 465m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated c 427m bwlch height, based on interpolation of 10m contouring between 420m – 430m.

Therefore, the name this hill is now listed by in the Y Pedwarau – The 400m Hills of Wales is Pt. 464.7m, and this is being used as the authors have not found an appropriate name for the hill either through historic research and/or local enquiry. 

 

The full details for the hill are: 

Group:  Hirddywel 

Name:  Pt. 464.7m 

Previously Listed Name:  Pen yr Onnen 

OS 1:50,000 map:  136, 147 

Summit Height:  464.7m (LIDAR) 

Summit Grid Reference:  SO 04162 68135 (LIDAR) 

Bwlch Height:  428.9m (LIDAR) 

Bwlch Grid Reference:  SO 04102 68713 (LIDAR) 

Drop:  35.8m (LIDAR) 

 

Myrddyn Phillips and Aled Williams (April 2025)

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

 

Pt. 474.4m (NY 381 113) 

There has been a Significant Height Revision to a hill that was considered for listing 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 Pt. 474.4m (NY 381 113)

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 hill is being listed by the point (Pt. 474.4m) notation, and it is adjoined to the Helvellyn group of hills, which are situated in the English Lake District, and it is positioned with the A591 road to its west and the A592 road to its east, and has the village of Glenridding towards the north.

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 15m of drop, based on an estimated c 472m summit height and an estimated c 457m col height, with both heights based on interpolation of 10m 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 Pt. 474.4m (NY 381 113)

LIDAR analysis gives the height of this hill as 474.4m positioned at NY 38179 11348, and when compared to its originally listed summit 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 474.4m and this was derived from LIDAR analysis, this is 2.4m higher than the originally listed c 472m summit height, which was based on interpolation of 10m contouring that appears on the Ordnance Survey 1:25,000 Explorer map. 

 

The full details for the hill are:

Group:  Helvellyn

Name:  Pt. 474.4m

OS 1:50,000 map:  90

Summit Height (New Height):  474.4m (LIDAR)

Summit Grid Reference:  NY 38179 11348 (LIDAR)

Col Height:  460.9m (LIDAR)

Col Grid Reference:  NY 38166 11274 (LIDAR)

Drop:  13.5m (LIDAR)

 

Myrddyn Phillips and Aled Williams (April 2025)

 

Mapping Mountains – Significant Name Changes – 200m Twmpau

 

Pen y Bryn (SO 075 896) 

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 Pen y Bryn (SO 075 896)

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 Hirddywel group of hills, which are situated in the northern part of South Wales (Region B, Sub-Region B2), and it is positioned with minor roads to its west, south and east, and the A489 road to its north-east, and has the town of Y Drenewydd (Newtown) towards the east north-east.

When the original 200m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was not included in the accompanying Hills to be surveyed sub list, as it was considered not to meet the criteria then used for this sub category.

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed under the point (Pt. 239m) notation with 27m of drop, based on the 239m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and the 212m bwlch spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map. 

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 246 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 as a part of Pen y Bank farm in the apportionments, with this a probable typo for Pen y Bryn, which it appears as on the Tithe map, with the details on the Tithe map appearing in the parish named as Penstrowed and in the county named as Montgomery. 

Extract from the apportionments

Therefore, the name this hill is now listed by in the 200m Twmpau is Pen y Bryn, and this was derived from the Tithe map. 

 

The full details for the hill are:

Group:  Hirddywel

Name:  Pen y Bryn

Previously Listed Name:  Pt. 239m   

OS 1:50,000 map:  136

Summit Height:  238.6m (LIDAR) 

Summit Grid Reference:  SO 07529 89658 (LIDAR) 

Bwlch Height:  210.5m (LIDAR) 

Bwlch Grid Reference:  SO 07074 89710 (LIDAR) 

Drop:  28.1m (LIDAR) 

 

Myrddyn Phillips (April 2025)

 

 

Mapping Mountains – Summit Relocations – The Welsh P15s

Cae Cwar y Tŷ (SN 907 499) 

There has been a Summit Relocation to a hill that is listed in the 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 Cae Cwar y Tŷ (SN 907 499)

The criteria for the list that this summit relocation 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 name the hill is now listed by is Cae Cwar y Tŷ, and this was derived from the Tithe map, and it is adjoined to the Drygarn Fawr 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-west and east, and has the town of Llanwrtyd towards the south-west.

When the listing that became known as The Welsh P15s was being compiled, this hill was included in the accompanying sub list with 14m of drop, based on the 257m summit spot height positioned at SN 90720 49939 and the 243m bwlch spot height, both of which appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage 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 analysis gives the highest ground on this hill as 259.1m positioned at SN 90712 49930 and SN 90717 49931.  However, this is to the top of a raised field boundary and protocols dictate that as this is deemed a relatively recent man-made construct such ground is discounted from the height of a hill. 

LIDAR summit image of Cae Cwar y Tŷ (SN 907 499)

The height produced by LIDAR analysis to the natural summit of this hill is 259.0m and is positioned at SN 90705 49957, and this 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 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.

Therefore, the summit height produced by LIDAR analysis is 259.0m and is positioned at SN 90705 49957, this position is not given a spot height on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and is approximately 18 metres north-westward from where the 257m spot height was positioned and approximately 26 metres north-westward from the high point of the raised field boundary. 

 

The full details for the hill are: 

Group:  Drygarn Fawr 

Name:  Cae Cwar y Tŷ 

OS 1:50,000 map:  147

Summit Height:  259.0m (LIDAR)                                                           

Summit Grid Reference (New Position):  SN 90705 49957 (LIDAR)                                                  

Bwlch Height:  243.4m (LIDAR) 

Bwlch Grid Reference:  SN 90715 49674 & SN 90716 49675 (LIDAR) 

Drop:  15.6m (LIDAR) 

 

Myrddyn Phillips (April 2025)

  

Mapping Mountains – Hill Reclassifications – 100m Twmpau

 

Creigiau Cochion (SN 611 989) – 100m Sub-Twmpau deletion

There has been a deletion from the list of 100m 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 Creigiau Cochion (SN 611 989)

The criteria for the list that this deletion applies to are:

100m Twmpau – Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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. 

100m Twmpau by Myrddyn Phillips

The name the hill is now listed by is Creigiau Cochion and this was derived from the Tithe map, and it is adjoined to the Tarren y Gesail group of hills, which are situated in the south-western part of North Wales (Region A, Sub-Region A3), and it is positioned with a minor road to its north and the A493 road to its west and south, and has the town of Tywyn towards the north-west.

When the original 100m 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, as it was considered not to meet the criteria then used for this sub category.

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-assessed and it was listed with an estimate c 20m of drop, based on the 168m 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 148m bwlch height, based on interpolation of 10m contouring between 140m – 150m. 

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.

Therefore, the deletion of this hill from 100m Sub-Twmpau status is due to LIDAR analysis, resulting in a 168.3m summit height and a 148.3m bwlch height, with these values giving this hill 19.98m of drop, which is insufficient for it to be classified as a 100m Sub-Twmpau. 

 

The full details for the hill are: 

Group:  Tarren y Gesail 

Name:  Creigiau Cochion 

OS 1:50,000 map:  135

Summit Height:  168.3m (LIDAR) 

Summit Grid Reference:  SN 61176 98937 (LIDAR) 

Bwlch Height:  148.3m (LIDAR) 

Bwlch Grid Reference:  SN 61236 98904 (LIDAR) 

Drop:  19.98m (LIDAR) 

 

Myrddyn Phillips (April 2025)