Mapping Mountains – Hill Reclassifications – Humps

Bryn Mawr (SJ 251 190) – Subhump addition

This is the twenty seventh in a series of Hill Reclassification posts that detail hills whose status has been altered in the listing of the Humps (HUndred Metre Prominences) through map study and / or surveys that I have conducted.

Bryn Mawr (SJ 251 190)

This and forthcoming posts are retrospective as many of these hill reclassifications were initiated from studying the Ordnance Survey enlarged mapping that is hosted on the Geograph website, or in this instance from a survey with the Trimble GeoXH 6000, and for the reclassifications that affected the Humps the survey of this hill took place on the 08.08.15.

The listing of Humps was published in book format by Lulu in 2009 and entitled More Relative Hills of Britain, its author; Mark Jackson gives credit to a number of people who contributed toward the formation of this list, these include; Eric Yeaman, Alan Dawson, Clem Clements, Rob Woodall, Bernie Hughes, Pete Ridges and others.  When the list was published in book format there were 2987 Humps listed with their criteria being any British hill that has 100m or more of drop, accompanying the main list is a sub category entitled Subhumps, with the criteria being any British hill that has 90m or more and below 100m of drop.

More Relative Hills of Britain by Mark Jackson

The details for the reclassification appear below:

There has been a reclassification to the listing of the Humps (HUndred Metre Prominences) instigated by a survey with the Trimble GeoXH 6000 which took place on the 08.08.15.

Prior to the survey with the Trimble GeoXH 6000 Mark Jackson had listed this hill with 85m of drop based on a 173m summit height and an 88m bwlch height. 

The hill is adjoined to the Carnedd Wen group of hills and is situated overlooking the B 4393 road which is to its north and east and the A 483 road to its south-east, and has the Montgomery Canal to its east and the Afon Efyrnwy (River Vyrnwy) to its north, and is positioned between the small communities of Llansantffraid-ym-Mechain to the west north-west, Llanymynech to the north-east, Four Crosses to the east south-east and Ardllin (Arddleen) towards the south.

Bryn Mawr was surveyed using a Trimble GeoXH 6000 by Myrddyn Phillips on the 08.08.15 resulting in a 90m drop value, with a summit height of 178.1m (converted to OSGM15) and a bwlch height of 88m based on the spot height that appears on the Ordnance Survey enlarged mapping hosted on the Geograph website, with this drop value being sufficient for this hill to be classified as a Subhump.

The addition of this hill to Subhump status was accepted by Mark Jackson on the 21.12.15 and the listing of the Humps was updated accordingly.

The Trimble GeoXH 6000 gathering data at the summit of Bryn Mawr

The full details for the hill are:

Name:  Bryn Mawr

Summit Height:  178m (178.1m converted to OSGM15)

OS 1:50,000 map:  126

OS 1:25,000 map:  240

Summit Grid Reference:  SJ 25119 19058 (as listed in the Humps)

Drop:  90m

Myrddyn Phillips (November 2017)