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

Brandy Hill (SN 213 133) and Castell Meherin (SN 146 117) – Dominant re-twinning

Approaching the summit of Brandy Hill

The summit of Castell Meherin

There has been a re-twinning of two hills in the Y Trechol – The Dominant Hills of Wales list, with their summit height, their location and drop initially confirmed by LIDAR analysis and subsequently by summit surveys with the Trimble GeoXH 6000 which were conducted by Myrddyn Phillips, with the latter taking place on the 1^st August 2018.

The criteria for the listing that this re-twinning 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 addition Welsh P30 hills whose prominence is 33.33% or more and below 50% of their absolute height, with the Introduction to the Mapping Mountains publication of this list appearing on the 3^rd December 2015.

When the Y Trechol - The Dominant Hills of Wales list was first compiled these two hills were listed as twin summits based on their 205m summit heights on Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps and which are both adjoined to triangulation pillars.

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

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

The two summits are a part of the Brandy Hill group of hills, which are situated in the south-western part of Mid and West Wales (Region B, Sub-Region B4), and are positioned with the A 477 road to their south, and the A 40 road to their north, with the B 4328 nearer and to the summit of Brandy Hill to its north-west and the B 4314 nearer and to the summit of Castell Meherin to its north.

These two hills were then separated and de-twinned based on the flush bracket heights adjoined to their trig pillars, resulting in Brandy Hill being listed as the higher hill and therefore the hill included in the Dominants list.  The flush bracket height for each hill is given below:

Brandy Hill:  206.047m at SN 21342 13381

Castell Meherin:  205.258m at SN 14646 11773

However, the trig pillar on Brandy Hill is positioned on a raised embankment that forms part of a field boundary.  Whereas the trig pillar on Castell Meherin is positioned on the raised embankment of an ancient hill fort.  As raised field boundaries are considered a recent man-made construct and not a part of the natural height of a hill and ancient hill forts are considered as permanent in nature and now a part of the hill, the highest natural ground at the base of the field boundary on Brandy Hill was taken for the height of this hill, and this is also where LIDAR analysis places this hill’s summit, whereas ground at the base of the trig pillar on Castell Meherin was taken as the height of this hill’s summit.  The results of each Trimble survey and their measurement offsets are given below:

Brandy Hill:  205.477 – 0.40m offset = 205.077m

Castell Meherin:  206.257m – 1.18m offset = 205.077m

Remarkably the Trimble GeoXH 6000 gave the height of each hill as equal to the nearest millimetre.  However, although these hills are now considered as Dominant twin summits, Brandy Hill is being prioritised for the drop value given in the 200m Twmpau list and the values associated with this are also given below.      

Gathering data at the summit of Brandy Hill

Gathering data at the summit of Castell Meherin

Therefore, as the Trimble GeoXH 6000 survey resulted in each summit having the same 205.077m height Brandy Hill and Castell Meherin are now re-twinned.

The full details for each hill are:

Group:  Brandy Hill

Name:  Brandy Hill

OS 1:50,000 map:  158

Summit Grid Reference:  SN 21352 13359

Summit Height:  205.1m (converted to OSGM15)

Bwlch Grid Reference:  SN 14049 17973 (LIDAR)

Drop Summit to Bwlch:  151.6m (Trimble summit and LIDAR bwlch)

Drop Bwlch to ODN:  53.5m (LIDAR)

Dominance:  73.92% (Trimble summit and LIDAR bwlch)

Group:  Brandy Hill

Name:  Castell Meherin

OS 1:50,000 map:  158

Summit Grid Reference:  SN 14646 11773

Summit Height:  205.1m (converted to OSGM15)

Bwlch Grid Reference:  SN 18517 12805 (LIDAR, natural bwlch)

Drop Summit to Bwlch:  42.8m (Trimble summit and LIDAR bwlch)

Drop Bwlch to ODN:  162.2m (LIDAR, natural bwlch)

Dominance:  20.89% (Trimble summit and LIDAR bwlch)

For details on the survey of Brandy Hill

For details on the survey of Castell Meherin

Myrddyn Phillips (January 2019)

Mapping Mountains – Trimble Surveys – Brandy Hill

01.08.18  Castell Meherin (SN 146 117)

The summit of Castell Meherin (SN 146 117)

Castell Meherin was the sixth and last hill that Suzanne and I visited during the day, we could have pressed on and visited and surveyed a seventh, but with Suzanne’s son waiting for us in Caerfyrddin (Carmarthen) we decided to call a halt to our little bagging bonanza after visiting this hill’s summit.

The hill is positioned with the B4314 to its north and has a minor road to its south, and it was from the south that we approached.  Castell Meherin has a 205m map height, which matches that of Brandy Hill (SN 213 133) and these two summits were once classified as twin Marilyns, but the accolade as the accepted higher hill has gone to that of Brandy Hill in recent years, and as one had already been Trimbled earlier in the day I was looking forward to the result of this survey which I suspected would confirm the present classification of each hill (little did I know that they would come out exactly the same; 205.077m!)

I parked on the grass verge, just sufficiently off of the minor road not to course obstruction and we headed toward an access gate that led up a field, by now the afternoon’s blue sky had been replaced with monochrome cloud cover that heralded a weather front predicted to bring heavy and consistent overnight drizzle.

We aimed for a gap in the boundary hedge toward the top right of the second field we entered, according to the map this is where the ancient earthworks are situated that give their name to this hill, it is also where a trig pillar sits atop one of the embankments, however when we arrived all we saw was bracken, and masses of it.

As we approached the base of the mass of fern I just caught a quick glimpse of the top of the trig pillar, it seemed as if it was floating on the bed of bracken, beached and almost unobtainable.  I entered the jungle of bracken but quickly gave up and reversed what little distance I had made, perhaps entering from the far northerly corner would be easier?

We looked for an access path as we walked around the base of the embankment, none was found, and so I dived in from the far north-eastern corner and made head-way through bracken that almost swamped me and which was chest high, with sections over my head, this was proving fun!

Being swamped by bracken

Progress was being made but it felt more like swimming than hill walking, and once in the ditch it was only a short steep pull up to the embankment where the trig pillar and the summit of the hill is situated, Suzanne quickly joined me.

The high point of Castell Meherin is close to the base of the trig pillar and approximately the same height as its base which is placed on a lump of concrete, and as this ground was overgrown with bracken and bramble I placed the Trimble on top of the trig pillar and we sat under it as it beeped away gathering its allotted data.

Gathering data at the summit of Castell Meherin

Once five minutes of data were gathered I closed the equipment down, packed it away and we reversed our inward route back to the field below.  It had been a fun day out with Suzanne visiting and Trimbling six hills, with four of them Marilyns.  Next stop Caerfyrddin (Carmarthen) where an excellent Indian meal awaited.

Survey Result:

Castell Meherin (significant name change)

Summit Height:  205.1m (converted to OSGM15) (Dominant re-twinned with Brandy Hill [SN 21352 13359] with the Trimble result giving the height of both summits exactly the same; 205.077m)

Summit Grid Reference:  SN 14646 11773

Bwlch Height:  162.2m (LIDAR)

Bwlch Grid Reference:  SN 18517 12805 (LIDAR)

Drop:  42.8m (Trimble summit and LIDAR bwlch) (Brandy Hill is being listed as the prioritised summit for drop purposes)

Dominance:  20.89% (Brandy Hill is being listed as the prioritised summit for dominance purposes)

For further details please consult the Trimble Survey Spreadsheet

Mapping Mountains – Significant Name Changes – 200m Twmpau

Castell Meherin (SN 146 117)

There has been a Significant Name Change to a hill that is listed in the 200m Twmpau, with the summit height and drop of the hill being confirmed by LIDAR analysis, with a subsequent Trimble GeoXH 6000 summit survey, with both conducted by Myrddyn Phillips.

Using the LIDAR technique has substantiated that the natural bwlch of this hill is still, just, intact, as a minor road passes over this point, with the following results produced through LIDAR analysis:

162.482m bwlch on minor road at SN 18485 12815

162.237m natural bwlch at SN 18517 12805

These positions are aligned on the hill to hill traverse and even though the bwlch on the minor road is higher, it is the natural bwlch position and its height that forms the quoted drop value of this hill, as this exists it is prioritised over any man-made construct.

LIDAR image of the bwlch of Castell Meherin with the points where the white contours meet being the road to the west and the natural bwlch to the east

LIDAR image of the summit of Castell Meherin

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 category entitled the 200m Sub-Twmpau consisting of all Welsh hills at or above 200m and below 300m in height that have 20m or more and below 30m of drop.  With the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

The hill is adjoined to the Brandy Hill group of hills, which are situated in the south-western part of Mid and West Wales (Region B, Sub-Region B4), and is positioned with the B 4328 road to its north and has the town of Arberth (Narberth) towards the north-west.

LIDAR image of Castell Meherin

The hill appeared in the 200m P30 list on Geoff Crowder’s v-g.me website under the invented name of Middleton Hill, with an accompanying note stating; Name from farm to the South-West.  

Middleton Hill

205m

SN146118

158

36

Trig pillar. Name from farm to the South-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.  My preference was to use farm names and put Pen, Bryn or Moel in front of them or when the farm had an English name use the word Top or Hill after the name.  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.

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 given the number 36 on the Tithe map, with enclosed land close to it given the number 33, these 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 has part of same given to it and this refers to the near field given the number of 33, and this is given the name of Part of Castle Merrin on the Tithe map, the details of which appear in the county named as Pembrokeshire and in the parish of Ludchurch.

Extract from the Tithe map

Extract from the Tithe map

Extract from the apportionments

With any upland place-name it is advantageous to substantiate it from a second source, and in the case of this hill this can initially be done through contemporary and historical Ordnance Survey maps, as the Tithe map implies that the land where the summit of this hill is situated is either known as Castle Merrin or it is adjoined to a farm known by the same name.

Therefore, contemporary Ordnance Survey maps were examined and there is a farm given the name of Castle Mehren on the 1:25,000 Explorer map which is positioned north north-east of the summit of this hill at SN 148 120, and as there are a series of ancient earthworks that take in the land comprising the upper part of this hill, in all likelihood the farm took its name from that of the earthworks. 

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

However, although the Tithe map gives a name for the enclosed land at the summit of this hill, and the contemporary Ordnance Survey 1:25,000 Explorer map substantiates the use of a farm name in relation to the Tithe information, it is historical Ordnance Survey maps that give the name of these ancient earthworks.

Since publication of these P30 lists on Geoff Crowder’s v-g.me website there have been a number of Ordnance Survey maps made available online, some of these are historical 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 enlarged map on the Geograph website.  Two of the historical maps now available are the Ordnance Survey Draft Surveyors map which formed the basis for the Ordnance Survey One-Inch ‘Old Series’ map, and both maps give the name of Castle Merrin in relation to this hill. 

The Draft Surveyors maps consist of the preliminary drawings made by the Ordnance Survey’s surveyors between the 1780s and 1840 and formed the basis for the first publicly available One-Inch map.  They were drawn at scales of six inches to the mile for areas considered of particular military significance and down to two inches to the mile for other areas.  Fair copies were then produced from these preliminary drawings to one inch to the mile and then copper plates were prepared for printing.  The Draft Surveyors maps for the whole of Wales are now available online and they form an important part in the study of Welsh upland place-names as they bridge the timeframe between the late 18^th century and the mid-19^th century when the Ordnance Survey produced their first One-Inch maps.

Extract from the Ordnance Survey Draft Surveyors map

The One-Inch ‘Old Series’ map was the first map that the 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 timeframe leading up to the production of the Ordnance Survey base map of the Six-Inch series.

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

The use of the name Castle Merrin, which is now presented by the farm name of Castle Mehren on contemporary Ordnance Survey maps is an anglicisation of the originator word which is Welsh.  Research online quickly found what name is the originator for these anglicised versions, this name is Castell Meherin, and this is substantiated from historical records as given below in an extract from the Royal Commission on the Ancient and Historical Monuments in Wales and Monmouthshire:

Extract from the Royal Commission on the Ancient and Historical Monuments in Wales and Monmouthshire 

The name of Castell Meherin is also substantiated by present day documentation, some of which is given by Coflein, which is the online database for the National Monuments Record of Wales and also by a number of other online sites, including Cadw, which is the historic environment service of the Welsh Government and part of the Tourism and Culture group. 

As the ancient earthworks comprise two distinct elements these are sometimes referred to as Castell Meherin West and Castell Meherin East, with the name also documented as Castell Meherin Camps, but all are derivatives of their originator; this being Castell Meherin.

Therefore, the name this hill is now listed by in the 200m Twmpau is Castell Meherin and this was derived from historic and contemporary documentation.

The full details for the hill are:

Group:  Brandy Hill

Name:  Castell Meherin

 

Previously Listed Name:  Middleton Hill 

OS 1:50,000 map:  158

Summit Height:  205.1m (converted to OSGM15)

Summit Grid Reference:  SN 14646 11773

Bwlch Height:  162.2m (LIDAR)

Bwlch Grid Reference:  SN 18517 12805 (LIDAR) 

 

Drop:  42.8m (Trimble summit and LIDAR bwlch)


For details on this hill's summit survey

Myrddyn Phillips (October 2018)