Mapping Mountains – Significant Name Changes – The Welsh P15s

 

Y Garreg Las (SN 768 098) 

There has been a Significant Name Change to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Y Garreg Las (SN 768 098)

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

The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10^th May 2019. 

The Welsh P15s by Myrddyn Phillips

The hill is adjoined to the Mynydd Du group of hills, which are situated in the southern part of South Wales (Region B, Sub-Region B5), and it is positioned with a minor road to its immediate north-east, and west, the A4068 road farther to its north-east and the A4067 road to its south-east, and has the community of Y Gurnos towards the east south-east. 

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

When the listing that became known as The Welsh P15s was being compiled, this hill was listed under the point (Pt. 157m) notation and included in the P14 sub list with an estimated c 14m of drop, based on the 157m summit spot height positioned at SN 76897 09754 that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map and an estimated c 143m bwlch height, based on interpolation of 5m contouring between 140m – 145m that appeared on the OS Maps website.  Latterly the interactive mapping hosted on the WalkLakes website gives this hill a 158m summit spot height. 

Extract from the interactive mapping hosted on the WalkLakes website

As the summit of this hill comprises bounded land the details for it were examined on the Tithe map.  The term Tithe map is generally given to a map of a Welsh or English parish or township and which was prepared after the 1836 Tithe Commutation Act.  This act allowed tithes to be paid in cash rather than goods.  The Tithe maps gave names of owners and occupiers of land in each parish and importantly for place-name research they also included the name of enclosed land.  This enclosed land is usually based on a field system, however not every field is given a name, but many are and especially so in Wales. 

Extract from the Tithe map

The enclosed land where the summit of this hill is situated is given the number 1829 on the Tithe map, this can be cross referenced against the apportionments; it is these apportionments that give the name of the owner or occupier of the land as well as the name of the land.  The land where the summit of this hill is situated is named as Y Garreg Las in the apportionments, with the details on the Tithe map appearing in the parish of Llan-giwg and in the county named as Glamorgan. 

Extract from the apportionments

Therefore, the name this hill is now listed by in The Welsh P15s is Y Garreg Las and this was derived from the Tithe map. 

 

The full details for the hill are: 

Group:  Mynydd Du 

Name:  Y Garreg Las

Previously Listed Name:  Pt. 157m 

OS 1:50,000 map:  160

Summit Height:  158.5m (LIDAR)                                                           

Summit Grid Reference:  SN 76803 09804 (LIDAR) 

Bwlch Height:  141.7m (LIDAR) 

Bwlch Grid Reference:  SN 76797 09723 (LIDAR) 

Drop:  16.75m (LIDAR) 

 

My thanks to Aled Williams for advice relating to the listed name of this hill

Myrddyn Phillips (April 2024)