Mapping Mountains – Significant Name Changes – The Welsh P15s

 

Y Dinas Ucha (SH 818 826) 

There has been a Significant Name Change to a hill that was 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 Dinas Ucha (SH 818 826)

The criteria for the list that this name change was applicable 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 Hiraethog group of hills, which are situated in the northern part of North Wales (Region A, Sub-Region A2), and it is positioned with the coast to its immediate north-east and the B5115 road to its south-west, and has the town of Llandudno towards the west.

When the listing that became known as The Welsh P15s was being compiled, this hill was included in the main list under the point (Pt. c 42m) notation with an estimated c 15m of drop, based on an estimated c 42m summit height and an estimated c 27m bwlch height, with both heights based on interpolation of 5m contouring. 

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

However, it was not until LIDAR became available that the numerical 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.

LIDAR analysis gives the natural summit of this hill as 41.8m and with a 28.2m bwlch height, these values give this hill 13.6m of drop, which is insufficient for it to be classified as a Welsh P15.

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 41 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 Dinas Ucha in the apportionments, with the details on the Tithe map appearing in the parish of Llandudno and in the county named as Caernarfon. 

Extract from the apportionments

Therefore, the name this hill is now listed by is Y Dinas Ucha and this was derived from the Tithe map. 

 

The full details for the hill are: 

Group:  Mynydd Hiraethog 

Name:  Y Dinas Ucha

Previously Listed Name:  Pt. c 42m 

OS 1:50,000 map:  116

Summit Height:  41.8m (LIDAR)                                                           

Summit Grid Reference:  SH 81890 82674 (LIDAR)                                                  

Bwlch Height:  28.2m (LIDAR) 

Bwlch Grid Reference:  SH 81903 82535 (LIDAR) 

Drop:  13.6m (LIDAR) 

 

Myrddyn Phillips (December 2024)