The first list to the Welsh
200m P30 hills was published on Geoff Crowder’s website v-g.me in 2000; this
list preceded the list of TuMPs by nine years, the list proved a very useful
resource for the TuMP compilation for this category of hill.
The Welsh 200m P30 list
documents all hills in Wales that are at or above 200m in height and are below
300m in height, to qualify for the main list each hill requires a minimum of
30m of prominence.
The hills listed below are
updates to the Welsh 200m P30 list originally published on Geoff Crowder's
website. To see the original list click {here}
The original published list had
a Sub-List which was entitled ‘Hills to Survey’. This list consisted of all hills in Wales in
the stipulated height band that have a minimum of 20m of prominence, but do not
meet the minimum 30m of prominence to enter the main list, according to
Ordnance Survey map spot heights and contours.
Nowadays the standard Sub-List takes in all hills that have a minimum of
20m of prominence. However, the Hills to
Survey Sub-List discounted hills whose map spot heights gave a drop value of
less than 30m, but more than 20m. By
doing so, the only hills that were Sub-Listed were those that map values
dictated stood a chance of entering the main list, for example; if a hill had a
summit spot height of 250m and a bwlch spot height of 221m, it was not listed
in the Hills to Survey Sub-List as with 29m of drop I thought it did not stand
a chance of main list qualification.
When compiling the Sub-List I
was measuring many hills for P30 status using a basic levelling technique,
please click {here} for more information concerning this. I now know that Ordnance Survey spot heights
have a standard margin of uncertainty of + / - 3m associated with their
accuracy. Therefore many hills that were
not listed in the original Sub-List may have sufficient drop to enter the main
list. Because of this the Sub-List has
been altered to include all hills that have a minimum of 20m of drop but are
not known to attain the minimum 30m of drop to enter the main list.
The hills listed below are
those major amendments to the original Welsh 200m P30 list as it appears on
Geoff’s website. There are many hills
that have been promoted from the Hills to Survey Sub-List to the main list,
whilst there are many additions to the Sub-List now that it has been
standardised to include all 20m minimum but below 30m drop hills.
When the 200m P30 list was
first published it was the first to this category of hills and in some way it
and its other 100m height band lists paved the way for Clem’s data that later
appeared on the RHB file database and then for the TuMPs listing by Mark
Jackson.
As well as the first P30 list
to this height band the list is now the first to include a comprehensive
Sub-List.
TuMP baggers beware; as the
main list also includes P30’s not listed by Mark Jackson, so if you want to
visit all P30’s you’ll have to include some non TuMPs to do so.
The list will be updated on a
weekly basis and will be done so through each Group category, starting from the
north and working south. The Twenty
Eighth Group is Y Mynydd Du.
Y
Mynydd Du
North from SN 834 127 following
the Afon Tawe to SN 771 083 and the Afon Twrch to bwlch at SN 739 135,
continuing north of the Afon Aman (River Amman) to SN 622 105, continuing east
of the Afon Llwchwr (River Loughor) to SN 622 132 and the Afon Marlas to bwlch
at SN 620 178 and the Afon Cennen to SN 632 218, continuing south of the Afon Tywi
(River Towy) to SN 753 327 and the Afon Bran to SN 770 342, continuing south of
the Afon Gwydderig to bwlch at SN 871 299 and the Nant Logyn to SN 883 288 and
the Afon Wysg (River Usk) to SN 901 290, continuing west of the Afon Crai to the
Cray Reservoir at SN 883 220, continuing from SN 877 207 following the
Blaen-crai to bwlch at SN 870 195 and the Nant Tywynni to the Afon Tawe (River
Tawe) at SN 848 172 to SN 834 127.
Bordering with Mynydd Epynt to the north, Elenydd and Mynydd Sylen to
the west, Penlle’ rcastell and Bryniau Cymoedd to the south and Fforest Fawr to
the east.
Twmpau - 200m updates
Pen
y Lan 268m SN 663 206
This hill was always a prime
candidate for promotion from the Sub-List as it has a 268m summit spot height,
and bwlch contouring between c 230m – c 240m, with the height of the bwlch
estimated as c 235m, giving this hill c 33m of drop. The Ordnance Survey enlarged Geograph map has
two 238m spot heights on the area of the bwlch, one is on a road at SN 667 210,
the other is at SN 672 210, both are considered not to be placed at the
critical bwlch.
Pt.
238m 238m SN 672 232
Another hill that is promoted
from the Sub-List and one whose name reverts to the Pt. notation, as it was
previously listed as Maesydderwen, which is a name that was taken from
buildings to the west of the summit. As
the height of the bwlch has been estimated as c 203m high, based on bwlch
contouring between c 200m – c 210m, it gives this hill c 35m of drop.
Pt.
238m 238m SN 795 343
This hill appeared in the
original Sub-List under a part invented name of Twyn y Gwerddon, this was based
on the name of buildings eastward of the summit, it now reverts to the Pt.
notation for this list as the blog author does not know an appropriate name for
it. The bwlch contouring is between c
200m – c 210m, with the height of the bwlch estimated to be c 208m at SN 796
330, giving this hill c 30m of drop. As
of writing it is another P30 hill that does not appear in the TuMPs list.
Sub-Twmpau - 200m updates
Allt
Llwynmeredydd 219m SN 758 302
This hill has bwlch contouring
between c 190m – c 200m, with the bwlch height estimated as c 196m at SN 757
299. The 219m summit and c 196m bwlch
values give this hill c 23m of drop.
Pt.
208m 208m SN 645 171
Another hill name that follows
the Pt. notation as the blog author does not know an appropriate name for
it. The Ordnance Survey enlarged
Geograph map has a 186m spot height on the bwlch at SN 646 171, giving this hill
22m of drop.
Pt.
259m 259m SN 893 286
This hill follows the Pt.
notation for its name as no suitable name is known for it by the blog
author. The bwlch contouring is between
c 230m – c 240m, with the height of the bwlch estimated as c 237m and placed at
SN 887 282, giving this hill c 22m of drop.
Allt
Cwmnantybeudy 254m SN 793 304
With a summit spot height of
254m and an estimated bwlch height of c 233m, based on bwlch contouring between
c 230m – c 240m, this hill has c 21m of drop.
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