Mapping Mountains – Significant Name Changes – The Welsh P15s

Cae Mawr (SN 462 175) 

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 Cae Mawr (SN 462 175)

This hill is also listed as the natural summit for a Dual Summit 100m Twmpau and a Dual Summit Lesser Dominant hill along with the man-made summit of Safle Claddu Nant y Caws (SN 468174 and SN 469 174).  However, this hill also qualifies as a Welsh P15, without the distinction of it being a Dual Summit hill, with its bwlch listed adjoined to the higher man-made summit.

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 Sylen group of hills, which are situated in the southern part of South Wales (Region B, Sub-Region B5), and it is positioned with the A48 road to its north and a minor road to its south-west, and has the town of Caerfyrddin (Carmarthen) 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 appeared under the transposed name of Llwynmelyn, with an accompanying note stating; Name from buildings to the West.

Llwynmelyn

155m

SN464176

159

178

Clem/Yeaman. Trig pillar. Name from buildings to the West.

During my early hill listing I 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, with little consideration for the meaning of the name and where it was appropriately applied to.  My preference was to use farm names and put Pen, Bryn or Moel in front of them or as in this instance transpose the name of a farm and use it for that of the hill.  This is not a practice that I now advocate 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

When the listing that became known as The Welsh P15s was being compiled, this hill was included as a separate entry in the main list under the point (Pt. 155m) notation with an estimated c 17m of drop, based on the 155m summit spot height adjoined to a triangulation pillar positioned at SN 46405 17608 that appears on the Ordnance Survey 1:50,000 Landranger andf 1:25,000 Explorer map, and an estimated c 138m bwlch height, based on interpolation of 5m contouring between 135m – 140m.  With the higher man-made summit of Safle Claddu Nant y Caws forming a part of the Dual Summit P30 entry in the 100m Twmpau. 

Extract from the Tithe 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 apportionments

The enclosed land where the summit of this hill is situated is given the number 886 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 Cae Mawr in the apportionments, with the details on the Tithe map appearing in the parish named as Llangynnwr and in the county named as Carmarthen.

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

 

The full details for the hill are: 

Group:  Mynydd Sylen 

Name:  Cae Mawr

Previously Listed Name:  Llwynmelyn (original 100m P30 list) Pt. 155m (original P15 list when summits were separated) 

OS 1:50,000 map:  159

Summit Height:  155.1m (LIDAR)                                                           

Summit Grid Reference:  SN 46268 17566 (LIDAR)                                                  

Bwlch Height:  139.3m (LIDAR) 

Bwlch Grid Reference:  SN 46733 17459 (LIDAR) 

Drop:  15.8m (LIDAR) 

 

Myrddyn Phillips (May 2025)

 

  

Mapping Mountains – Summit Relocations – The Welsh P15s

 

Cae Mawr (SN 462 175) 

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 Mawr (SN 462 175)

This hill is also listed as the natural summit for a Dual Summit 100m Twmpau and a Dual Summit Lesser Dominant hill along with the man-made summit of Safle Claddu Nant y Caws (SN 468174 and SN 469 174).  However, this hill also qualifies as a Welsh P15, without the distinction of it being a Dual Summit hill, with its bwlch listed adjoined to the higher man-made summit.

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 Mawr, and this was derived from the Tithe map, and it is adjoined to the Mynydd Sylen group of hills, which are situated in the southern part of South Wales (Region B, Sub-Region B5), and it is positioned with the A48 road to its north and a minor road to its south-west, and has the town of Caerfyrddin (Carmarthen) towards the north-west.

When the listing that became known as The Welsh P15s was being compiled, this hill was included in the main list with an estimated c 17m of drop, based on the 155m summit spot height adjoined to a triangulation pillar positioned at SN 46405 17608 that appears on the Ordnance Survey 1:50,000 Landranger andf 1:25,000 Explorer map, and an estimated c 138m bwlch height, based on interpolation of 5m contouring between 135m – 140m. 

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 156.3m positioned at SN 46256 17561.  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 Mawr (SN 462 175)

The height produced by LIDAR analysis to the highest remaining natural ground of this hill is 155.1m and is positioned at SN 46268 17566, 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 the 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.

Therefore, the summit height produced by LIDAR analysis is 155.1m and is positioned at SN 46268 17566, 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 137 metres west south-westward from where the originally listed summit is positioned and approximately 12 metres east north-eastward from the high point of the raised field boundary. 

 

The full details for the hill are: 

Group:  Mynydd Sylen 

Name:  Cae Mawr 

OS 1:50,000 map:  159

Summit Height:  155.1m (LIDAR)                                                           

Summit Grid Reference (New Position):  SN 46268 17566 (LIDAR)                                                  

Bwlch Height:  139.3m (LIDAR) 

Bwlch Grid Reference:  SN 46733 17459 (LIDAR) 

Drop:  15.8m (LIDAR) 

 

Myrddyn Phillips (May 2025)

 

Mapping Mountains – Hill Reclassifications – 100m Twmpau

 

Cae Mawr (SN 462 175) and Safle Claddu Nant y Caws (SN 468 174) & (SN 469 174) – Dual Summit 100m Twmpau addition

There has been a Dual Summit addition to the list of the 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 Cae Mawr (SN 462 175) and Safle Claddu Nant y Caws (SN 468 174 & SN 469 174)

The criteria for the list that this addition 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

 

Dual Summit hills:

A hill classified as a Dual Summit is defined as one which has an extant natural summit coupled with that of a higher artificial summit, with the latter that can be described as stable in character.  In the main, these recent man-made constructions are the result of quarrying activities producing spoil tips, or as in this instance a landfill.  These recent man-made constructions are treated differently to ancient man-made constructions such as hill forts and tumuli, as if the latter are deemed stable and of an earthen character their age dictates that they can be viewed as being permanent in nature and are now effectively a part of the hill.  For those bagging Dual Summit hills, a visit to either the natural high point or the elevated man-made high point is sufficient to claim an ascent of the hill.  With the Dual Summit classification being a relatively new category and fist instigated in January 2018 for a Dual Summit Pedwar.

 

The name the hill is now listed by is Cae Mawr for the lower natural summit and Safle Claddu Nant y Caws for the higher man-made summit, and it is adjoined to the Mynydd Sylen group of hills, which are situated in the southern part of South Wales (Region B, Sub-Region B5), and the two summits are positioned with the A48 road to their north and a minor road to their south-west, and has the town of Caerfyrddin (Carmarthen) towards the north-west. 

When the original 100m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, the natural summit was included in the main P30 list with a 155m summit height, based on the spot height adjoined to a triangulation pillar positioned at SN 46405 17608 that appears on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map. 

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

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 then separated in to its two component parts, with the man-made summit listed with an estimated c 59m of drop, based on an estimated c 156m summit height and an estimated c 97m bwlch height, with both heights based on interpolation of 5m contouring that appeared on the interactive mapping hosted on the OS Maps website.  With the lower natural summit listed with a 155 summit height and the bwlch between these two summits estimated as c 138m, which if separating these hills would give an estimated c 17m of drop.

However, it was not until LIDAR became available that the details for these summits 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 addition of this hill to Dual Summit 100m Twmpau status is due to LIDAR analysis, resulting in a 155.1m summit height for the natural summit and a 163.8m summit height for the man-made summit, and a 98.5m bwlch height, with these values giving the natural summit 56.6m of drop and the man-made summit 65.3m of drop, with the details for the higher summit prioritised within the list. 

 

The full details for the hill are:

Group:  Mynydd Sylen

Name:  Cae Mawr (natural Dual Summit) and Safle Claddu Nant y Caws (artificial Dual Summit)

OS 1:50,000 map:  159

Summit Height:  155.1m (natural Dual Summit) (LIDAR) and 163.8m (artificial Dual Summit (LIDAR)

Summit Grid Reference:  SN 46268 17566 (natural Dual Summit) (LIDAR) and SN 46899 17416 & SN 46900 17411 (artificial Dual Summit) (LIDAR)

Bwlch Height:  98.5m (LIDAR)

Bwlch Grid Reference:  SN 39491 11374 & SN 39493 11375 (LIDAR)

Drop:  56.6m (natural Dual Summit) (LIDAR) and 65.3m (artificial Dual Summit) (LIDAR)

 

Myrddyn Phillips (January 2025)

 

Mapping Mountains – Significant Height Revisions – 100m Twmpau and Y Trechol – The Dominant Hills of Wales

Safle Claddu Nant y Caws (SN 468 174) & (SN 469 174) and Cae Mawr (SN 462 175) 

There has been a Significant Height Revision to a hill that is now listed as a Dual Summit in the 100m Twmpau 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 Cae Mawr (SN 462 175) and Safle Claddu Nant y Caws (SN 468 174) and (SN 469 174)

The criteria for the two listings that this height revision 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, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

100m Twmpau 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 the list is now available in its entirety on Mapping Mountains in Google Doc format. 

Y Trechol - The Dominant Hills of Wales by Myrddyn Phillips

Dual Summit hills:

A hill classified as a Dual Summit is defined as one which has an extant natural summit coupled with that of a higher artificial summit, with the latter that can be described as stable in character.  In the main, these recent man-made constructions are the result of quarrying activities producing spoil tips, or as in this instance a landfill.  These recent man-made constructions are treated differently to ancient man-made constructions such as hill forts and tumuli, as if the latter are deemed stable and of an earthen character their age dictates that they can be viewed as being permanent in nature and are now effectively a part of the hill.  For those bagging Dual Summit hills, a visit to either the natural high point or the elevated man-made high point is sufficient to claim an ascent of the hill.  With the Dual Summit classification being a relatively new category and fist instigated in January 2018 for a Dual Summit Pedwar.

The name the hill is now listed by is Safle Claddu Nant y Caws for the higher man-made summit and Cae Mawr for the lower natural summit, and it is adjoined to the Mynydd Sylen group of hills, which are situated in the southern part of South Wales (Region B, Sub-Region B5), and the two summits are positioned with the A48 road to their north and a minor road to their south-west, and has the town of Caerfyrddin (Carmarthen) towards the north-west.

When the original 100m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, the natural summit was included in the main P30 list with a 155m summit height, based on the spot height adjoined to a triangulation pillar positioned at SN 46405 17608 that appears on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map. 

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

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 then separated in to its two component parts, with the man-made summit listed with an estimated c 59m of drop, based on an estimated c 156m summit height positioned at SN 46909 17343 and an estimated c 97m bwlch height, with both heights based on interpolation of 5m contouring that appeared on the interactive mapping hosted on the OS Maps website.  With the lower natural summit listed with a 155 summit height and the bwlch between these two summits estimated as c 138m, which if separating these hills would give an estimated c 17m of drop.

However, it was not until LIDAR became available that the details for these summits 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 Safle Claddu Nant y Caws (SN 468 174) and (SN 469 174)

LIDAR analysis gives the highest ground at the man-made summit as 163.8m positioned at SN 46899 17416 & SN 46900 17411, and this compared to its previously listed summit height 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 or Harvey 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 to the data produced by the Trimble or by LIDAR analysis.

Therefore, the new listed summit height of this hill is 163.8m and this was derived from LIDAR analysis, this is 7.8m higher than the previous listed summit height of c 156m, which was based on interpolation of its uppermost 155m ring contour that appeared on the interactive mapping hosted on the OS Maps website.

 

ills of Wales, and are reproduced below@

The full details for the hill are:

Group:  Mynydd Sylen

Name:  Safle Claddu Nant y Caws (artificial Dual Summit) and Cae Mawr (natural Dual Summit)

OS 1:50,000 map:  159

Summit Height (New Height):  163.8m (artificial Dual Summit) and 155.1m (natural Dual Summit) (LIDAR)

Summit Grid Reference:  SN 46899 17416 & SN 46900 17411 (artificial Dual Summit) and SN 46268 17566 (natural Dual Summit) (LIDAR)

Bwlch Height:  98.5m (LIDAR)

Bwlch Grid Reference:  SN 39491 11374 & SN 39493 11375 (LIDAR)

Drop:  65.3m (artificial Dual Summit) and 56.6m (natural Dual Summit) (LIDAR)

Dominance:  39.89% (artificial Dual Summit) and 36.50% (natural Dual Summit) (LIDAR)

 

Myrddyn Phillips (July 2024)