Thursday 31 August 2017

Mapping Mountains – Hill Reclassifications – Humps


Pen-yr-allt (SN 486 219) – Hump reclassified to Subhump

This is the sixth 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 instigated.

The hill name used in this and forthcoming posts is that used in the listing of Humps, therefore individual names and their composition may not match those that are used in listings I am directly associated with.  However, I am of firm belief that listed hill names used by other authors should be respected when giving detail within other people’s lists, however inappropriate some hill names may be considered.

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, and for the reclassifications that affected the Humps the email I posted on the RHB Yahoo Group forum in relation to this hill was dated 01.05.12.

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) due to consulting the Ordnance Survey enlarged mapping that is hosted on the Geograph website, with these details being posted on the RHB Yahoo Group forum on 01.05.12.

Prior to this notification Mark Jackson had listed this hill as a Hump with c 100m of drop based on the 175m summit spot height given to a triangulation pillar on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and an estimated bwlch height of c 75m based on bwlch contouring at 10m intervals, interpolation of bwlch contouring was helped by the use of 5m contour intervals on the Ordnance Survey enlarged mapping hosted on the Geograph website and therefore the estimated bwlch height could be better refined to c 77m, and when coupled with this hill’s 175m summit spot height these values give this hill c 98m of drop, which is insufficient for it to retain its Hump status.

Extract from the Ordnance Survey enlarged mapping hosted on the Geograph website showing the 5m contour intervals at the bwlch of this hill

The hill appears under the name of Pen-yr-allt in the listing of the Humps, with this name having appeared in the original 100m Welsh P30 list published on Geoff Crowder’s v-g.me website with an accompanying note stating Name from buildings to the West.  As this hill comprises bounded land its details were examined on the Tithe map to the parish of Abergwili, and the enclosed land at the summit of this hill is named Cae Pant yr Lan, with the Lan part of this name possibly relating to buildings to the east of the hill, as shown on the extract from the Ordnance Survey Six-Inch map below.

Extract from the Ordnance Survey Six-Inch map showing the trig pillar symbol at the summit of this hill, the farm named Pen-yr-allt-fawr (on left and named Pen-yr-allt on current maps) and the buildings named Lan on the right

The hill is adjoined to the Mynydd Pencarreg range of hills and is situated overlooking the A40 road and the Afon Tywi (River Towy) to the south, with the small community of Nantgaredig to its south-east and the town of Caerfyrddin (Carmarthen) towards its west.

The reclassification of this hill from Hump to Subhump status was accepted by Mark Jackson and its new classification augmented in to the listing of the Humps on the 06.05.12.


The full details for the hill are:


Name:  Pen-yr-allt (as listed in the Humps)

Summit Height:  175m

OS 1:50,000 map:  159

OS 1:25,000 map:  186

Summit Grid Reference:  SN 48697 21963

Drop:  c 98m



Myrddyn Phillips (August 2017)


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