Mapping Mountains – Hill Reclassifications – Y Trichant – The 300m Hills of Wales

 

Pared y Cefn Hir (SH 661 148) – Sub-Trichant reclassified to Trichant

There has been confirmation of a reclassification to the list of Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail on contemporary maps produced from Ordnance Survey data and a subsequent Leica GS15 survey conducted by John Barnard, Graham Jackson and Myrddyn Phillips. 

Pared y Cefn Hir (SH 661 148)

The criteria for the list that this reclassification applies to are: 

Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant, with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop.  The list is authored by Myrddyn Phillips with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13^th May 2017, and the Introduction to the Mapping Mountains publication of the list appearing on the 1^st January 2022. 

Y Trichant - The 300m Hills of Wales by Myrddyn Phillips

The name the hill is listed by is Pared y Cefn Hir, and it is adjoined to the Cadair Idris group of hills, which are situated in the south-western part of North Wales (Region A, Sub-Region A3), and it is positioned with the A493 road to its north-west and minor roads to its south-west, south-east and east, and has the town of Abermaw (Barmouth) towards the west north-west. 

When the original 300m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was included in the Hills to be surveyed sub list, as it was considered not to meet the criteria then used for the main P30 category, with the 383m map heighted Bryn Brith (SH 664 153) listed as the prioritised P30. 

When the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with an estimated c 39m of drop, based on an estimated c 381m summit height and an estimated c 342 bwlch height, with both heights based on interpolation of 10m contouring that appear on the Ordnance Survey 1:25,000 Explorer map. 

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

Since the original publication of the Welsh P30 lists on Geoff Crowder’s v-g.me website there have been a number of maps made available online.  Some of these are historic such as the series of Six-Inch maps on the National Library of Scotland website.  Whilst others were digitally updated such as the Ordnance Survey Vector Map Local that was hosted on the Geograph website and which was entitled the Interactive Coverage Map, whilst others are current and digitally updated such as the interactive mapping on the Magic Maps and WalkLakes websites. 

The details for this hill were re-assessed when the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map became available online.  This mapping had many spot heights not on other publicly available Ordnance Survey maps and for this hill it had a 383m summit spot height and therefore it became twinned with the 383m map heighted Bryn Brith positioned at SH 664 153.  This spot height is also represented on the interactive mapping on the Magic Maps website. 

Extract from the Magic Maps website

Due to the twinning of Pared y Cefn Hir and Bryn Brith and the marginal Submarilyn status of the higher summit these hills were prioritised for a GNSS survey and this took place over two days and was conducted by John Barnard, Graham Jackson and Myrddyn Phillips using a Leica GS15, resulting in Pared y Cefn Hir being confirmed as the higher summit and the drop value confirmed as just below the 150m required for Marilyn status. 

Gathering data on the summit area of Pared y Cefn Hir with the offset between the set-up position and high point noted

Therefore, the confirmation of the reclassification of this hill from Sub-Trichant status is due to detail on contemporary maps produced from Ordnance Survey data and a subsequent Leica GS15 survey, resulting in a 383.1m summit height and a 233.7m bwlch height, with these values giving this hill 149.4m of drop, which is sufficient for it to be classified as a Trichant. 

 

The full details for the hill are: 

Group:  Cadair Idris 

Name:  Pared y Cefn Hir 

OS 1:50,000 map:  124

Summit Height:  383.1m (Leica GS15)                                                           

Summit Grid Reference:  SH 66199 14885 (Leica GS15) 

Bwlch Height:  233.7m (Leica GS15) 

Bwlch Grid Reference:  SH 65822 14423 (Leica GS15) 

Drop:  149.4m (Leica GS15) 

 

Myrddyn Phillips (March 2022)