Mapping Mountains – Significant Name Changes – 100m Twmpau

Lower Cil (SJ 185 016) 

There has been a Significant Name Change to a hill that is listed in the 100m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by LIDAR analysis and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips. 

LIDAR image of Lower Cil (SJ 185 016)

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 100m Twmpau by Myrddyn Phillips

The hill is adjoined to the Carnedd Wen group of hills which are situated in the south-eastern part of North Wales (Region A, Sub-Region A4), and it is positioned with the B4385 road to its west, a minor road to its south and the A483 road to its east, and has the village of Aberriw (Berriew) towards the south-south-east. 

When the original 100m 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-assessed and it was listed under the point (Pt. 158m) notation with an estimated c 21m of drop, based on the 158m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated c 137m bwlch height based on interpolation of 5m contouring between 135m – 140m. 

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

This was one of two hills visited on a walk with Linda during the Covid-19 keep local restrictions and after surveying its summit we descended to Lower Cil Farm (SJ 182 015) which is situated just to the west of the summit.  Approaching the farmyard we met George Pritchard who was working in one of the barns.  I introduced myself and explained my interest in upland place-names and in particular the name of the hill that we had just visited and which was just above George’s farm.  He explained that the hill does not have an individual name but the land where the summit is situated is known as Lower Cil, after the farm.  We chatted with George for ten minutes or so and he then kindly directed us on the continuation of our walk through the farmyard and across one of his fields to a crossing place over a stream. 

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

 

The full details for the hill are: 

Group:  Carnedd Wen 

Name:  Lower Cil

Previously Listed Name:  Pt. 158m 

OS 1:50,000 map:  136

Summit Height:  159.3m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SJ 18556 01630 (Trimble GeoXH 6000)

Bwlch Height:  137.8m (LIDAR)

Bwlch Grid Reference:  SJ 18939 01777 (LIDAR)

Drop:  21.5m (Trimble GeoXH 6000 summit and LIDAR bwlch) 

 

Myrddyn Phillips (July 2021)