Mapping Mountains – Significant Name Changes – 100m Twmpau

Bwlch Mawr (SH 777 755)

There has been a Significant Name Change to a hill that was listed in the 100m Twmpau, with the summit height, its location, the drop and status of the hill confirmed by LIDAR analysis, and a subsequent summit survey with the Trimble GeoXH 6000 conducted by Myrddyn Phillips, with the latter taking place on the 10^th October 2018.

LIDAR image of Bwlch Mawr

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 Carneddau group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is positioned with the B5106 road to its west and the Afon Conwy (River Conwy) to its east, and has the town of Conwy towards its north.

When the origin 100m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, the north-easterly 130m map heighted summit positioned at SH 781 758 and listed as Cae Alen was prioritised for P30 status over that of the south-westerly small uppermost 130m contour ring positioned at SH 777 755.

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

The details for this hill were re-assessed when the Ordnance Survey Vector Map Local became available online, this map is hosted on the Geograph website and is entitled the Interactive Coverage Map, and as an uppermost contour ring should be prioritised over that of a same map heighted spot height the south-westerly point positioned at SH 777 755 was now prioritised for P30 status and listed under the name of Iolyn Park.  This is a name that appears on contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps and is placed relatively close to this hill’s summit.

It was not until LIDAR became available and analysed that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales, and although LIDAR and the survey with the Trimble GeoXH 6000 confirm that Cae Alen (SH 78116 75814) is in fact higher than the summit positioned at SH 777 755 and the status of the P30 reverts to its original listed summit, it is still worthwhile documenting the change in this hill’s listed name. 

Before visiting this hill I met Richard Davies; an employee at the Gorse Hill Caravan Park, which takes in land to the immediate south of this hill.  During our conversation Richard referred to the hill as Bwlch Mawr, which is the name of the farm near to its summit and which appears on the Ordnance Survey Vector Map Local hosted on the Geograph website.  After visiting the adjacent southerly hill of Bryn Eithin (SH 77584 75224) I met the owner of the Gorse Hill Caravan Park; Rob Thomas-Evelyn, who also gave me the name of Bwlch Mawr for this hill and told me that the hill is known after the name of the farm.

Extract from the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map

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 78 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 Bwlch mawr in the apportionments, with the details on the Tithe map appearing in the parish of Gyffin and in the county named as Carnarvon [sic].

Extract from the apportionments

Therefore, the name this hill is now documented as is Bwlch Mawr, and this was derived from local enquiry and substantiated by the Tithe map.

The full details for the hill are:

Group:  Carneddau

Name:  Bwlch Mawr

Previously Listed Name:  Iolyn Park 

OS 1:50,000 map:  115

Summit Height:  128.4m (converted to OSGM15)

Summit Grid Reference:  SH 77790 75561

Bwlch Height:  110.9m (LIDAR)

Bwlch Grid Reference:  SH 78016 75713 (LIDAR)

 

Drop:  17.5m (Trimble summit and LIDAR bwlch)

For details of the summit survey of this hill

Myrddyn Phillips (April 2019)