Mapping Mountains – Significant Name Changes – 100m Twmpau

Boncan Fawr (SH 550 666)

There has been a Significant Name Change to a hill that is listed in the 100m Twmpau, with the hill’s bwlch height and location confirmed by LIDAR analysis and its summit height confirmed by a Trimble GeoXH 6000 survey, both conducted by Myrddyn Phillips with the latter taking place on the 2^nd October 2018.

The summit of Boncan Fawr (SH 550 666) with the Trimble GeoXH 6000 gathering data

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height with 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.

The hill is adjoined to the Glyderau group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and is positioned with the B4547 road to its north-east and the B4366 road to its south-east, and has the small city of Bangor towards its north north-east.

The hill originally appeared in the 100m P30 list on Geoff Crowder’s v-g.me website under the invented name of Bryn Ty-mawr with an accompanying note stating; Name from buildings to the South-East. 

Bryn Ty-mawr

154m

SH551666

114/115

17/263

Name from buildings to the South-East

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.  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

Prior to visiting this hill I called at Tŷ-mawr; the farm to the immediate south-east of the summit.  I was met by Jane who told me that the land where the summit of this hill is situated is no longer a part of Tŷ-mawr and it is now worked by Fachell, a farm situated to the west of the hill.

After visiting the hill I called at Fachell and was met by Llinos Jones who invited me in.  I’m indebted to the kindness and hospitality shown me over the years by the farming community and this visit is just one of many where this was shown, and the next half an hour with Llinos and her family proved a delight.

Llinos’ daughter; Elan phoned her father; Aled, who soon arrived and we sat and chatted about the hill and its name.  Aled explained that they know it as Boncan Fawr (pronounced Boncan and not Boncyn), with Aled being the fourth generation of his family to have farmed from Fachell.

The Jones family (L-R); Elan, Llinos, Aled, Elis and Bedwyr

Therefore, the name this hill is now listed by in the 100m Twmpau is Boncan Fawr, and this was derived from local enquiry.

The full details for the hill are:

Group:  Glyderau

Name:  Boncan Fawr

Previously Listed Name:  Bryn Ty-mawr 

  

OS 1:50,000 map:  114, 115

Summit Height:  153.6m (converted to OSGM15)

Summit Grid Reference:  SH 55099 66613

Bwlch Height:  110.0m (LIDAR)

Bwlch Grid Reference:  SH 55526 66115 (LIDAR)

 

Drop:  43.6m (Trimble summit and LIDAR bwlch)

For details on the summit survey of this hill

Myrddyn Phillips (February 2019)