Friday 22 February 2019

Mapping Mountains – Significant Name Changes – 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales


Yr Orsedd (SH 299 270)

There has been a Significant Name Change to a hill that is listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, its location, the drop and status of the hill confirmed by LIDAR analysis, and a subsequent summit survey with the Trimble GeoXH 6000 conducted by Myrddyn Phillips, with the latter taking place on the 3rd October 2018.

The summit of Yr Orsedd (SH 299 270)

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

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 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.

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, with the Introduction to the Mapping Mountains publication of this list appearing on the 3rd December 2015.

The hill is adjoined to the Pen Llŷn group of hills, which are situated in the western part of North Wales (Region A, Sub-Region A1), and the hill is encircled by minor roads with the coast to its south-west and east, and has the village of Abersoch towards its north-east.

This hill was first listed in the Hills to be surveyed sub-list that accompanied the original Welsh 30-99m P30 list published on Geoff Crowder’s v-g.me website, under the invented name of Bryn Llanengan, with an accompanying note stating; Name from village to the North-West.


Bryn Llanengan
64m
123
253
Name from village to the North-West


This hill was listed with a 64m summit height which is positioned at SH 295 266 and appeared as a spot height on the Ordnance Survey 1:25,000 Explorer map.  The details for this hill were reassessed when the Ordnance Survey Interactive Coverage Map hosted on the Geograph website became available online, and this map has a 66m spot height at SH 299 270 which is adjoined to the hill to the north-east, which only has an uppermost 60m ring contour on the 1:25,000 Explorer map.  Therefore the summit position of the listed hill was relocated and its drop value increased accordingly, with the Interactive Coverage Map also giving the south-westerly hill a second 64m map heighted summit, and LIDAR analysis confirms that the north-easterly of these two hills is the higher.

The old listed summit that is known locally as Bryn Tŷ Newydd

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 use the name of a near village and put the word Bryn in front of it.  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

I visited this hill along with Aled Williams and on our way back to the car I took the opportunity to call at one or two houses hoping to be directed toward the local farmer.  A woman was on the drive of the second house we called out and she was the partner of Wyn Roberts, who had been on his quad bike in an adjacent field when we were on the summit.  Having explained our interest in the hill’s name we were directed down the road to where Wyn would soon re-appear on his quad bike after checking on his herd of cows.

After flagging Wyn down and introducing ourselves he explained that the hill we had visited is known as Yr Orsedd and the lower hill to the south-west, that was first listed as the qualifying P30 is known as Bryn Tŷ Newydd.

Wyn Roberts

Therefore, the name this hill is now listed by in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales is Yr Orsedd, and this was derived from local enquiry.


The full details for the hill are:

Group:  Pen Llŷn

Name:  Yr Orsedd

Previously Listed Name:  Bryn Llanengan 

OS 1:50,000 map:  123

Summit Height:  67.5m (converted to OSGM15)

Summit Grid Reference:  SH 29952 27038

Bwlch Height:  32.0m (LIDAR)

Bwlch Grid Reference:  SH 29808 27337 (LIDAR)
 
Drop:  35.4m (Trimble summit and LIDAR bwlch)

Dominance:  52.52% (Trimble summit and LIDAR bwlch)



Myrddyn Phillips (February 2019)


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