Mapping Mountains – Hill Reclassifications – Humps

Foel Fras (SN 765 926) – Prioritised Twin Hump deletion

This is the twenty fourth 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.

Foel Fras (SN 765 926) on right of photo

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 18.05.14.

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 18.05.14.

Mark Jackson had originally listed this hill with c 105m of drop based on the 529m summit spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and an estimated bwlch height of c 424m based on bwlch contouring at 10m intervals.  This hill was listed as a prioritised Twin Hump along with two other non-prioritised Twin Hump 529m summit spot heighted hills which are positioned at SN 764 943 and SN 765 920.  Therefore, prior to the survey with the Trimble GeoXH 6000 this hill was listed as a prioritised Twin Hump.  

   

The hill is adjoined to the Pumlumon group of hills and is situated between the A 489 road to the north and the A 44 road to the south, and is positioned between the town of Machynlleth towards the north and the small community of Ffwrnais (Furnace) towards the west.

This hill and its adjacent twin map heighted summits were surveyed using a Trimble GeoXH 6000 by Myrddyn Phillips on the 18.05.14 resulting in a 528.7m (converted to OSGM15) summit height, which proved lower than the 529.4m (converted to OSGM15) summit at SN 764 943, with the other summit being 528.3m (converted to OSGM15) at SN 765 920, with this survey confirming this hill’s deletion from prioritised Twin Hump status with 67.6m of drop.

The deletion of this hill from prioritised Twin Hump status was accepted by Mark Jackson and it was removed from the listing of the Humps on 22.09.14.

Gathering data with the Trimble GeoXH 6000 at the summit of Foel Fras

The full details for the hill are:

Name:  Foel Fras

Summit Height:  528.7m (converted to OSGM15)

OS 1:50,000 map:  135

OS 1:25,000 map:  23, 215

Summit Grid Reference:  SN 76548 92610 (as listed in the Humps)

Drop:  67.6m (converted to OSGM15)

Myrddyn Phillips (October 2017)