Friday, 2 February 2018

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

Bryn y Gwynt (SH 599 449)

There has been a Significant Name Change to a hill that now appears in the following lists; 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the hill’s height, drop, dominance and status confirmed by analysis conducted by Aled Williams of data produced via LIDAR.

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

30-99m Twmpau – All Welsh hills at and above 30m and below 100m in height that have a minimum 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.  Accompanying the main Twmpau list is a sub list entitled Sub-Twmpau with this hill being reclassified from the 30-99m Sub-Twmpau category.  The criteria for 30-99m Sub-Twmpau status are all Welsh hills at and above 30m and below 100m in height that have 20m or more and below 30m of drop.

Y Trechol – The Dominant Hills of Wales – All Welsh P30 hills whose prominence equal or exceed half that of their absolute height.

The hill is situated in the Moelwynion range of hills and is placed in the Region of North Wales (Region A, Sub-Region A1), and is positioned with the A 4085 road to its north-east and has the Welsh Highland Railway to its immediate west and overlooks the Afon Glaslyn also to its west, and has the village of Beddgelert to its north north-west and the town of Porthmadog to its south south-west.

The hill appeared in the Hills to be surveyed sub list that accompanied the main Welsh P30 lists that were published on Geoff Crowder’s website under the name of Coed Hafod-y-llyn.  This is the name of the wood where the hill is situated and would be an appropriate name to use if a name for the hill itself did not exist.

Coed Hafod-y-llyn        56m        SH598448        12418

Hill list authors are prone to list a hill by the name that appears nearest to its summit on contemporary Ordnance Survey maps, without much consideration for its local or historical confirmation, or whether map placement is appropriate, or as in this case whether an individual name for the hill in preference to the name of the wood it is situated in, exists.  This is not a practice I now advocate as with time and inclination place-name date can be improved by asking local people or by examining historical documents, through this form of research an appropriate name for the hill can usually be found, and in the case of this hill it was local knowledge from Aled Williams coupled with historical information from the Ordnance Survey series of Six-Inch maps that gave the name of Bryn y Gwynt for this hill.  

Extract from the series of Ordnance Survey Six-Inch maps

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

The full details for the hill are:

Group:  Moelwynion

Name:  Bryn y Gwynt

Previously Listed Name:  Coed Hafod-y-llyn

Summit Height:  58.2m (data via LIDAR)

OS 1:50,000 map:  124

Summit Grid Reference:  SH 59949 44915 
Drop:  30.2m (data via LIDAR)

Dominance:  51.89% 

My thanks to Aled Williams for sending the details of this hill to me

Myrddyn Phillips (February 2018)

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