Foel Grafiau (SN 765 920) – Non-prioritised Twin Hump
deletion
This is the twenty fifth 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 that was listed as Foel Grafiau in the Humps and still is in the Tumps (SN 765 920) |
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, 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 30m of
drop based on the 529m summit spot height that appears on the Ordnance Survey 1:25,000
Explorer map and an estimated bwlch height of c 499m based on bwlch contouring
at 10m intervals. This hill was listed
as a non-prioritised Twin Hump along with
two other 529m summit spot heighted hills which are positioned at SN 764 943
(previously listed as non-prioritised Twin
Hump) and SN 765 926 (previously listed as prioritised Twin Hump). Therefore, prior
to the survey with the Trimble GeoXH 6000 this hill was listed as a
non-prioritised Twin Hump.
The hill appeared under the name of Foel Grafiau in the listing
of the Humps, this is the name of a 493m
map heighted hill that is listed as a 400m
Sub-Pedwar and which is positioned at SN 959 920. However, research via the Tithe map confirms
the hill that appeared in the Humps
by the name of Foel Grafiau and which is still listed in the Tumps as being the highest point on the
former sheep-walk of Lluest y Rhos, with the hill listed in the Y Pedwarau as Mynydd Lluest y Rhos (see Significant Name Changes).
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 528.3m (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 528.7m (converted to OSGM15) at SN 765 926, with this survey
confirming this hill’s deletion from non-prioritised Twin Hump status with 30.0m
of drop.
The deletion of this hill from non-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 positioned at SN 765 920 |
The full details for the hill are:
Name: Foel Grafiau (as
listed in the Humps)
Summit Height: 528.2m
(as listed in the Humps) (528.3m converted to OSGM15)
OS 1:50,000 map: 135
OS 1:25,000 map: 23,
215
Summit Grid Reference:
SN 76546 92035 (as listed in the Humps)
Drop: 30.0m
Myrddyn Phillips (November 2017)
No comments:
Post a Comment