Mapping Mountains – Hill Reclassifications – Y Trechol – The Dominant Hills of Wales

Nant y Caws Landfill (SN 468 174) & (SN 469 174) and Cae Mawr (SN 462 175) – Lesser Dominant reclassified to Dual Summit Lesser Dominant

There has been confirmation of a reclassification to the list of the 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 Nant y Caws Landfill (SN 468 174 & SN 469 174)

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

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 Nant y Caws Landfill 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 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 confirmation of the reclassification of this hill to Dual Summit Lesser Dominant status is due to LIDAR analysis, resulting in a 163.8m summit height for the man-made summit and a 155.1m summit height for the natural summit, and a 98.5m bwlch height, with these values giving the man-made summit 65.3m of drop and 39.89% dominance and the natural summit 56.6m of drop and 36.50% dominance, which is sufficient for Dual Summit Lesser Dominant status, with the details for the higher summit prioritised within the list. 

 

The full details for the hill are:

Group:  Mynydd Sylen

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

OS 1:50,000 map:  159

Summit 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 (June 2024)

  

Mapping Mountains – Significant Name Changes – 30-99m Twmpau

Bryn (SH 782 798) 

There has been a Significant Name Change to a hill that is listed in the 30-99m 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 Bryn (SH 782 798)

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

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height that have 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 30m and below 100m 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. 

30-99m Twmpau by Myrddyn Phillips

The hill is adjoined to the Mynydd Hiraethog group of hills, which are situated in the northern part of North Wales (Region A, Sub-Region A2), and it is positioned with the A546 road to its west and the B5115 road to its south-east, and has the town of Deganwy towards the north.

The hill appeared in the original Welsh 30-99m P30 list on Geoff Crowder’s v-g.me website, under the transposed name of Deganwy, with an accompanying note stating; Name from surrounding district.

Deganwy

90m

SH782799

115

17

Name from surrounding district

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.  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 town 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

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 176 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 Bryn in the apportionments, with the details on the Tithe map appearing in the parish of Eglwys Rhos and with the county unnamed. 

Extract from the apportionments

Therefore, the name this hill is now listed by in the 30-99m Twmpau is Bryn, and this was derived from the Tithe map. 

 

The full details for the hill are:

Group:  Mynydd Hiraethog

Name:  Bryn

Previously Listed Name:  Deganwy 

OS 1:50,000 map:  115

Summit Height:  87.2m (LIDAR) 

Summit Grid Reference:  SH 78234 79892 (LIDAR)               

Bwlch Height:  65.6m (LIDAR) 

Bwlch Grid Reference:  SH 78372 79790 (LIDAR) 

Drop:  21.6m (LIDAR) 

 

Myrddyn Phillips (June 2024)

  

Mapping Mountains – Hill Reclassifications – Y Trichant – The 300m Hills of Wales

Mynydd Trallong (SN 965 311) – Sub-Trichant deletion

There has been a deletion from the list of Y Trichant – The 300m Hills of Wales, 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 Mynydd Trallong (SN 965 311)

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

Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant, with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop.  The list is authored by Myrddyn Phillips with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13^th May 2017, and the Introduction to the Mapping Mountains publication of the list appearing on the 1^st January 2022. 

Y Trichant - The 300m Hills of Wales by Myrddyn Phillips

The name the hill is now listed by is Mynydd Trallong and this was derived from the Ordnance Survey Draft Surveyors map, and it 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 minor roads to its north-east and south, and the A40 road farther to its south, and has the village of Pontsenni (Sennybridge) towards the west south-west.

When the original 300m 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-evaluated and it was listed with 2om of drop, based on the 377m summit spot height that appears on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and the 357m 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

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 Sub-Trichant status is due to LIDAR analysis, resulting in a 376.9m summit height and a 357.3m bwlch height, with these values giving this hill 19.6m of drop, which is insufficient for it to be classified as a Sub-Trichant. 

 

The full details for the hill are: 

Group:  Mynydd Epynt 

Name:  Mynydd Trallong 

OS 1:50,000 map:  160

Summit Height:  376.9m (LIDAR)                                                           

Summit Grid Reference:  SN 96522 31151 (LIDAR) 

Bwlch Height:  357.3m (LIDAR) 

Bwlch Grid Reference:  SN 96272 31300 & SN 96275 31303 (LIDAR) 

Drop:  19.6m (LIDAR) 

 

Myrddyn Phillips (June 2024)

 

 

 

 

  

Mapping Mountains – Hill Reclassifications – The Welsh P15s

 

The Welsh P15s – Hill Reclassifications

The Welsh P15s are all Welsh hills that have a minimum of 15m of drop, irrespective of their height.  Accompanying the main P15 list is a sub list entitled; The Welsh Sub-P15s, with the qualification to this sub category being all Welsh hills with 14m or more and below 15m of drop.

The list is authored by Myrddyn Phillips and the posts that have appeared on Mapping Mountains detailing the additions, reclassifications and deletions to the main P15 list and the sub list that are below P20 and therefore documented in other lists, appear below presented chronologically in receding order.

Mapping Mountains - Hill Reclassifications - The Welsh P15s

Allt y Geifr (SN 762 284) – Welsh P15 reclassified to Welsh Sub-P15 (37th reclassification)

Significant Height Revisions post for Allt y Geifr

 

There has been a reclassification to the list of 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 Allt y Geifr (SN 762 284)

The criteria for the list that this reclassification 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 listed by is Allt y Geifr, and it is adjoined to the Mynydd Du group of hills, which are situated in the southern part of South Wales (Region B, Sub-Region B5), and it is positioned encircled by minor roads with the A4069 road farther to its north-west and south-west, and has the village of Llangadog towards the west.

When the listing that became known as The Welsh P15s was being compiled, this hill was included in the main P15 list with an estimated c 16m of drop, based on the 174m 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 158m bwlch height, based on interpolation of 5m contouring between 155m – 160m that appeared on the OS Maps website. 

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 reclassification of this hill to Welsh Sub-P15 status is due to LIDAR analysis, resulting in a 171.1m summit height and a 156.9m bwlch height, with these values giving this hill 14.2m of drop, which is insufficient for it to be included in the main list of The Welsh P15s. 

 

The full details for the hill are: 

Group:  Mynydd Du 

Name:  Allt y Geifr 

OS 1:50,000 map:  146, 160

Summit Height:  171.1m (LIDAR)                                                           

Summit Grid Reference:  SN 76221 28491 (LIDAR) 

Bwlch Height:  156.9m (LIDAR) 

Bwlch Grid Reference:  SN 76558 28873 (LIDAR) 

Drop:  14.2m (LIDAR) 

 

Myrddyn Phillips (June 2024)

Mapping Mountains - Hill Reclassifications - The Welsh P15s

Pt. 181.4m (SN 731 303) – Welsh Sub-P15 reclassified to Welsh P15 (36th reclassification)

 

There has been a reclassification to the list of 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 Pt. 181.4m (SN 731 303)

The criteria for the list that this reclassification 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 being listed by the point (Pt. 181.4m) notation as an appropriate name for it either through local enquiry and/or historic research has not been found by the author, and it is adjoined to the Mynydd Du group of hills, which are situated in the southern part of South Wales (Region B, Sub-Region B5), and it is positioned with the A4069 road to its west and a minor road to its south-east, and has the village of Llangadog towards the south-west.

When the listing that became known as The Welsh P15s was being compiled, this hill was included in the P14 sub list with an estimated c 14m of drop, based on the 181m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated c 167m bwlch height, based on interpolation of 5m contouring between 165m – 170m that appeared on the OS Maps website. 

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 reclassification of this hill from Welsh Sub-P15 status is due to LIDAR analysis, resulting in a 181.4m summit height and a 166.2m bwlch height, with these values giving this hill 15.2m of drop, which is sufficient for it to be included in the main list of The Welsh P15s. 

 

The full details for the hill are: 

Group:  Mynydd Du 

Name:  Pt. 181.4m 

OS 1:50,000 map:  146, 160

Summit Height:  181.4m (LIDAR)                                                           

Summit Grid Reference:  SN 73163 30392 (LIDAR) 

Bwlch Height:  166.2m (LIDAR) 

Bwlch Grid Reference:  SN 73315 30299 (LIDAR) 

Drop:  15.2m (LIDAR) 

 

Myrddyn Phillips (June 2024)