Change
Register
Y
Trechol – The Dominant Hills of Wales
Y Trechol
– The Dominant Hills of Wales are the
Welsh P30 hills whose prominence equal or exceed half that of their absolute
height, with the minimum qualifying mark given as a percentage (50%). The list was conceptualized after adding drop
values to the hand written Master Lists that took in the P30 hills of Wales
that were published on Geoff Crowder’s v-g.me website, this was during 2006 and
2007 and the compilation of what was to become Y Trechol – The Dominant Hills of Wales followed soon afterward.
The original title for the list was the UPP’s, an
abbreviation for the Ultra Prominent Peaks of Wales; this title was later
changed to The Dominant Hills of Wales. The change of name was instigated after a
discussion with Mark Trengove who informed me that the same concept of Dominance had been used by Eberhard
Jurgalski in written format in 2001 and in published format in 2004. I also realised that the original title could
be confused with the listing of 5,000ft prominence world peaks that are known
as the Ultras, their title having
been shortened from the Ultra Prominent
Peaks, as it was sensible not to use a working title that was similar to
another that used different criteria I opted for the title of Y Trechol - The Dominant Hills of Wales,
with the term of Dominance used to
describe it, and the words Y Trechol
being the Welsh for The Dominants. Accompanying the main list is a sub list
entitled The Lesser Dominant Hills of
Wales, these are the additional P30 Welsh hills whose prominence is 33% or
more and below 50% of their absolute height.
Although Y Trechol –
The Dominant Hills of Wales was originally
compiled in 2006 – 2007 after drop values were added to the Welsh P30 lists, the
listing did not commence publication until 3rd December 2015, with
‘commence’ being the operative word as this is ongoing with bi-weekly, monthly,
bi-monthly or quarterly instalments of hill groups being published on Mapping
Mountains.
Although the criteria has remained the same in the Dominant and Lesser Dominant list, the listing has benefited greatly since its
first compilation with the advent of independent surveyors using GPS / GNSS
receivers, the analysis of LIDAR data
and the availability of an expanded range of online Ordnance Survey maps all
adding greater accuracy to the numerical data.
However, it is not just numerical data that has seen this list develop
since its first inception, as local enquiry and historical research are
enhancing the place-name data used for the listed hill names.
It seems fitting that the list of Y Trechol – The Dominant Hills of Wales should now benefit from a
detailed Change Register, and although the changes to this list have been catalogued
on the Mapping Mountains site it will be useful to list all status changes to
the list since first compilation and present them in a Change Register.
The Change Register to Y
Trechol – The Dominant Hills of Wales appears below with the
reclassifications to the Dominant
list being detailed chronologically in receding order.
Change Register
Y Trechol
– The Dominant Hills of Wales
Carreg Rhoson 28m at SM 67228 25658
Carreg Rhoson (SM 672 256) is the island on the right of this photo |
This hill was deleted from Dominant status on the 22.03.24, with
it previously listed as a Dominant hill with 100.00% dominance due to a small
uppermost 30m ring contour on the Ordnance Survey 1:25,000 Explorer map. Its deletion is due to detail on the
DataMapWales with a 28m spot height appearing on this mapping. Dominant total decreases by one and confirmed
as 268.
The Rookery 102.6m at SN 61191 22707
LIDAR image of The Rookery (SN 611 227) |
The
reclassification of this hill to Dominant status was announced when the Hill
Reclassifications post was published on Mapping Mountains on the 20.04.22. The hill was previously listed with an estimated c 49m of drop and 48.04% dominance,
based on the 102m summit spot height that appears on the Ordnance Survey
1:25,000 Explorer map and an estimated c 53m bwlch height based on
interpolation of 10m contouring between 50m – 60m. Its reclassification to Dominant status is due
to LIDAR analysis conducted by Myrddyn
Phillips, resulting in a 102.6m summit height and a 50.3m bwlch height, with
these values giving this hill 52.2m drop and 50.94% dominance. Dominant total increases by one and confirmed as
269.
Dinas Fach 30.45m at SM 82559 22659
LIDAR image of Dinas Fach (SM 825 226) |
The
addition of this hill to Dominant status was incorporated in to the list on the
09.12.20 and announced when the Hill Reclassifications post was published on
Mapping Mountains on the 17.10.21. The
hill was previously not classified due to inconsistency between contours on the
Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map. Its addition to Dominant status is due to Joe Nuttall who produced a summit analysis
programme using LIDAR, and then by LIDAR analysis initially conducted by Jim
Bloomer and subsequently by Myrddyn Phillips, resulting in a 30.45m summit
height and a 0.3m bwlch height, with these values giving this hill 30.15m of
drop and 99.01% dominance. Dominant total increases
by one and confirmed as 268.
Ynys Dafydd 52.8m at SH 64636 17484
LIDAR image of Ynys Dafydd (SH 646 174) |
The
addition of this hill to Dominant status was announced when the Hill
Reclassifications post was published on Mapping Mountains on the 07.09.21. The hill was previously listed with an estimated c 27m of drop based on an estimated c
42m summit height and an estimated c 15m bwlch height, with both values based
on interpolation of 10m contouring that appears on the Ordnance Survey 1:25,000
Explorer map. Its addition to Dominant
status is due to Joe Nuttall who produced a summit analysis programme using LIDAR, and then by LIDAR analysis initially
conducted by Jim Bloomer and subsequently by Myrddyn Phillips, resulting in a 52.8m
summit height and a 17.1m bwlch height, with these values giving this hill 35.7m
of drop and 67.61% dominance. Dominant total increases
by one and confirmed as 267.
The Park 85.6m at SN 66441 93678
LIDAR image of The Park (SN 664 936) |
The
reclassification of this hill to Dominant status was announced when the Hill
Reclassifications post was published on Mapping Mountains on the 28.07.21. The hill was previously listed with an estimated c 41m of drop and 49.40% dominance, based
on an estimated c 83m summit height and the 42m bwlch spot height that appears
on the Ordnance Survey 1:25,000 Explorer map.
Its reclassification
to Dominant status is due to LIDAR
analysis conducted by Myrddyn Phillips, resulting in an 85.6m summit height and
a 42.7m bwlch height, with these values giving this hill 42.9m drop and 50.09%
dominance. Dominant total increases
by one and confirmed as 266.
Ynys Fach 43.5m at SN 66845 95141
LIDAR image of Ynys Fach (SN 668 951) |
This
hill’s addition to Dominant status was announced when the Hill
Reclassifications post was published on Mapping Mountains on the 26.03.21. The hill was previously listed with an estimated c 27m of drop based on an estimated c
34m summit height and an estimated c 7m bwlch height, with both values based on
interpolation of 10m contouring that appears on the Ordnance Survey 1:25,000
Explorer map. Its addition to Dominant
status is due to Joe Nuttall who produced a summit analysis programme using LIDAR, and then by LIDAR analysis initially
conducted by Jim Bloomer and subsequently by Myrddyn Phillips resulting in a
43.5m summit height and a 2.1m bwlch height, with these values giving this hill
41.3m of drop and 95.10% dominance. Dominant total increases
by one and confirmed as 265.
Glan y Morfa 59.2m at SH 43819 67923
LIDAR image of Glan y Morfa (SH 438 679) |
This
hill’s addition to Dominant status was announced when the Hill
Reclassifications post was published on Mapping Mountains on the 10.03.21. The hill was previously listed with 27m of
drop based on twin tops both with
a 59m summit spot height (59m at SH 43811 67899 on the Ordnance Survey 1:25,000
Explorer map and 59m at SH 45087 68972 on the Ordnance Survey Vector Map Local hosted
on the Geograph website and which was entitled the Interactive Coverage Map)
and a bwlch height of 32m that appears as a spot height on the Ordnance Survey
1:25,000 Explorer map. Its addition to Dominant
status is due to LIDAR analysis conducted by Myrddyn Phillips resulting in a 59.2m summit height and a 27.9m
bwlch height, with these values giving this hill 31.3m of drop and 52.85%
dominance, with the bwlch height taken to a railway cutting. Dominant total increases by one and confirmed as
264.
Pen y Foel 122.5m at SH 42575 84415
The Trimble GeoXH 6000 gathering data at the summit of Pen y Foel (SH 425 844) |
This hill’s reclassification to Dominant status was announced when the Hill Reclassifications post was published on Mapping Mountains on the 04.03.21. The hill was previously listed with 49.40% dominance based on the 122.5m summit height derived from a Trimble GeoXH 6000 survey and a 62m bwlch height based on the spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map. Its reclassification to Dominant status is due to partial LIDAR coverage of its bwlch, resulting in a more accurate interpolation of its bwlch height to an estimated c 61m, with these values giving this hill an estimated c 62m of drop and 50.21% dominance. Dominant total increases by one and confirmed as 263.
Wilcrick Hill 69.8m at
ST 41128 87829
LIDAR image of Wilcrick Hill (ST 411 878) |
This hill’s reclassification to Dominant
status was announced when the Gwent Is Coed group of hills was published on Mapping Mountains on the 03.07.19, with a
subsequent Hill Reclassifications post being published on Mapping Mountains on the 10.09.20. The hill was originally
listed with 49.28% dominance based on the 69m summit and 35m bwlch spot heights
that appear on the Ordnance Survey 1:25,000 Explorer map. However, as the 35m spot height appears
between 30m – 35m contouring the drop value for this hill was re-assessed,
resulting in an estimated c 33m bwlch height being used, giving c 36m of drop
and 52.17% dominance. The confirmation
of its reclassification to a Dominant hill is due to LIDAR analysis conducted
by Myrddyn Phillips, resulting in a 69.8m summit height and a 33.3m bwlch
height, with these values giving this hill 36.4m of drop and 52.21% dominance. Dominant total increases by one and confirmed
as 262.
Cae Rosser 72.7m at SO 38857 00521
LIDAR image of Cae Rosser (SO 388 005) |
This hill’s reclassification to Dominant status was
announced when the Gwent Is Coed group of hills was published on Mapping Mountains on the 03.07.19, with a subsequent Hill Reclassifications post being published on Mapping Mountains on the 21.07.20.
The hill was originally listed with 49.32% dominance based on a 73m
summit height and an estimated c 37m bwlch height, with these values giving
this hill c 36m of drop. Its
reclassification to a Dominant hill is due to LIDAR analysis conducted by
Myrddyn Phillips, resulting in a 72.7m summit height and a 32.2m bwlch height,
with these values giving this hill 40.5m of drop and 55.68% dominance. Dominant total increases by one and confirmed
as 261.
Trostrey Hill 199.3m at SO 36920 05188
LIDAR image of Trostrey Hill (SO 369 051) |
The reclassification of this hill from Dominant status was announced when the Mynyddoedd Duon group was published on Mapping Mountains on the 03.07.19, with a subsequent Hill Reclassifications post being published on Mapping Mountains on the 12.03.20. The hill was originally listed with 68.84% dominance based on a 199m summit height and a 62m bwlch height, with these values giving this hill 137m of drop. Its reclassification to Lesser Dominant status is due to LIDAR analysis conducted by Myrddyn Phillips, resulting in this hill being lower than the adjacent hill of Coed y Bwnydd (SO 36613 06919) and therefore their bylchau swapped. LIDAR analysis gives this hill a 199.3m summit height and a 129.1m bwlch height, with the former taken to remaining natural ground with LIDAR also giving a 199.5m height positioned at SO 36920 05184 to a raised field boundary that is excluded from the height of this hill as it is considered a relatively recent man-made construct, with these values giving this hill 70.2m of drop and 35.23% dominance. Dominant total decreases by one and confirmed as 260.
Coed y Bwnydd 201.4m at SO 36613 06919
LIDAR image of Coed y Bwnydd (SO 366 069) |
The reclassification of this hill to Dominant status was announced when the Mynyddoedd Duon group was published on Mapping Mountains on the 03.07.19, with a subsequent Hill Reclassifications post being published on Mapping Mountains on the 01.02.20. The hill was originally listed with 34.69% dominance based on a 196m summit height and an estimated c 128m bwlch height, with these values giving this hill c 68m of drop. Its reclassification to Dominant status is due to LIDAR analysis conducted by Myrddyn Phillips, resulting in this hill being higher than the adjacent Trostrey Hill (SO 36920 05188) and therefore their bylchau swapped. LIDAR analysis gives this hill a 201.4m summit height and a 59.4m bwlch height, with the former taken to an earthen embankment that forms a part of an ancient hill fort and the latter taken to a road cutting, both of which conform with the criteria used within this list, with these values giving this hill 142.0m of drop and 70.50% dominance. Dominant total increases by one and confirmed as 261.
Ash Wood 206.4m at SO 48011 12229
LIDAR image of Ash Wood (SO 480 122) |
This hill’s reclassification to Dominant status was
announced when the Mynyddoedd Duon group was published on Mapping Mountains on
the 03.07.19, with a subsequent Hill Reclassifications post being published on Mapping Mountains on the 22.01.20. The
hill was originally listed with 49.03% dominance based on an estimated c 206m
summit height and an estimated c 105m bwlch height, with these values giving this
hill c 101m of drop. Its
reclassification to a Dominant hill is due to LIDAR analysis conducted by
Myrddyn Phillips, resulting in a 206.4m summit height and a 97.6m bwlch height,
with the latter taken to a track cutting which conforms with the criteria used
within this list, with these values giving this hill 108.8m of drop and 52.69%
dominance. Dominant total increases by
one and confirmed as 260.
Dinas Powys 69.4m at ST 14823 72225
LIDAR image of Dinas Powys (ST 148 722) |
The addition of this hill to Dominant status was announced
when the Bro Morgannwg group was published on Mapping Mountains on the 03.06.19,
with a subsequent Hill Reclassifications post being published on Mapping Mountains on the 10.11.19. The hill was
not included in the original 30-99m height band of Welsh P30 hills and its
addition as a Dominant hill was confirmed by LIDAR analysis conducted by
Myrddyn Phillips, resulting in a 69.4m summit height and a 33.6m bwlch height,
with these values giving this hill 35.8m of drop and 51.57% dominance. Dominant
total increases by one and confirmed as 259.
Ash Tip 50.0m at ST 03170 66338
LIDAR image of Ash Tip (ST 031 663) |
This hill’s addition to Dominant status was announced when
the Bro Morgannwg group was published on Mapping Mountains on the 03.06.19,
with a subsequent Hill Reclassifications post being published on Mapping Mountains on the 27.10.19. The hill was
not included in the original 30-99m height band of Welsh P30 hills as there
were no contours of note taking in what is now a man-made hill on contemporary
Ordnance Survey maps of the day. Its
addition as a Dominant hill was confirmed by LIDAR analysis conducted by
Myrddyn Phillips, resulting in a 50.0m summit height and a 12.4m bwlch height,
with these values giving this hill 37.6m of drop and 75.20% dominance. Dominant
total increases by one and confirmed as 258.
Pt. 65.9m 65.9m at ST 35225 94717
LIDAR image of Pt. 65.9m (ST 352 947) |
The reclassification of this hill to Lesser Dominant status
was announced when the Cymoedd Gwent group of hills was published on Mapping Mountains on the 03.05.19, with a subsequent Hill Reclassifications post being published on Mapping Mountains on the 14.09.19.
The hill was originally listed with 50.00% dominance based on the 66m
summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map
and the 33m bwlch spot height that appears on the Ordnance Survey Vector Map
Local hosted on the Geograph website and which is entitled the Interactive
Coverage Map. The reclassification of
this hill is due to LIDAR analysis conducted by Myrddyn Phillips resulting in a
65.9m summit height and a 34.3m bwlch height, with these values giving this
hill 31.6m of drop and 47.93% dominance.
Dominant total decreases by
one and confirmed as 257.
Mynydd Machen 363.2m at ST 22381 90013
LIDAR image of Mynydd Machen (ST 223 900) |
This hill was excluded when the Cymoedd Gwent group was published on Mapping Mountains on the 03.05.19, with a subsequent Hill Reclassifications post being published on Mapping Mountains on the
18.07.19. The hill was originally listed
with 53.31% dominance based on the 362m summit spot height and an estimated
bwlch height of c 169m, with these values giving this hill c 193m of drop. The status of this hill was re-assessed as
the Ordnance Survey Vector Map gave a 375m summit spot height to Mynydd y Grug
(ST 177 906); an adjoining and connected hill.
The latter summit height is the product of mine spoil and as the summit
is considered solid and stable the respective bylchau for each hill was swapped
resulting in the drop of Mynydd Machen decreasing. The confirmation of this hill’s deletion from
Dominant status is due to LIDAR analysis conducted by Myrddyn Phillips
resulting in a 363.2m summit height and a 250.6m bwlch height, with these
values giving this hill 112.7m of drop and 31.01% dominance. Dominant
total decreases by one and confirmed as 258.
Warren Hill 44.5m at SS 73667 94066
LIDAR image of Warren Hill (SS 736 940) |
This hill’s addition to Dominant status was announced when
the Cymoedd Morgannwg group was published on Mapping Mountains on the 03.04.19,
with a subsequent Hill Reclassifications post being published on MappingMountains on the 24.06.19. The hill was not
included in the original 30-99m height band of Welsh P30 hills, which was an
oversight on my part as it met the criteria then used for the sub list. However, it was included as a P30 based on
detail from the Ordnance Survey Vector Map Local hosted on the Geograph website
and which is entitled the Interactive Coverage Map. Its addition as a Dominant hill was confirmed
by LIDAR analysis conducted by Myrddyn Phillips, resulting in a 44.5m summit
height and a 13.2m bwlch height, with these values giving this hill 31.3m of
drop and 70.35% dominance. Dominant total increases by one and
confirmed as 259.
Mynydd y Glyn 377m at ST 03193 89647
This hill’s status as a Dominant
hill was announced when the Cymoedd Morgannwg group was published on Mapping Mountains on the 03.04.19, with a subsequent Hill Reclassifications post being published on Mapping Mountains on the 14.05.19.
The hill was originally listed with 48.28% dominance based on the 377m
summit spot height and an estimated bwlch height of c 195m, with these values
giving this hill c 182m of drop. The
reclassification of this hill is due to LIDAR bwlch analysis conducted by
Myrddyn Phillips resulting in a bwlch height of 187.7m, which when coupled with
its 377m summit height gives this hill 189m of drop and 50.20% dominance. Dominant
total increases by one and confirmed as 258.
Bryn 36.7m at SH 42656 36173
LIDAR summit image of Bryn |
This hill’s addition to Dominant
status was accepted shortly after Chris Pearson suggested the hill as a P30
initialising LIDAR analysis conducted by Chris Crocker which confirmed its
status, with a retrospective Hill Reclassifications post being published on Mapping Mountains on the 05.02.19. The
hill was originally listed with an estimated c 28m of drop, which was amended
to c 29m of drop when the Ordnance Survey Interactive Coverage Map became
available online via the Geograph website.
It was subsequently analysed by LIDAR and surveyed using the Trimble GeoXH 6000 by Myrddyn Phillips, with the former showing that this hill is not a
natural P30 and only now accepted as one as a railway cutting has destroyed the
natural bwlch and reduced its height and therefore increased the drop value of
this hill. The confirmation of this
hill’s addition to Dominant status is due to a Trimble GeoXH 6000 summit survey
and LIDAR analysis of its bwlch, resulting in a 36.7m summit height and a 6.6m
bwlch height, with these values giving this hill 30.0m of drop and 81.88%
dominance. Dominant total increases by one and confirmed as 257.
Cae Ffwyn Uchaf 66.6m at SN 58825 00532
LIDAR image of Cae Ffwyn Uchaf |
This hill’s reclassification from Dominant to Lesser Dominant status was announced when the
Mynydd Penlle’rcastell group of hills were published on Mapping Mountains on
the 03.12.18, with a Hill Reclassifications post being published on the 04.02.19. The hill was initially classified as a Dominant based on a 67m summit spot
height and an estimated bwlch height of c 33m, with these values giving this
hill c 34m of drop and 50.75% dominance.
This hill’s reclassification to Lesser
Dominant status is due to LIDAR
analysis conducted by Myrddyn Phillips resulting in a 66.6m summit height and a
36.0m bwlch height, giving this hill 30.6m of drop and 45.90% dominance. Dominant
total decreases by one and confirmed as 256.
Hidden Slabs Stack 6.5m at SS 11902 98247
This hill was not included as a Dominant hill when the Brandy Hill group of hills was published on
Mapping Mountains on the 03.09.18, and a Hill Reclassifications post was then
published on the 06.10.18. The hill was
listed as a Dominant based on
information received from Dave Viggers who is now one of the Vice Presidents of
the Climber’s Club, the approximate height had been given as c 30m, but site
visits by a number of people including Jon Glew, Douglas Law, Rob Woodall and
Adrian Rayner brought in to doubt the existence of a prominent sea stack at
this position. The confirmation of this hill’s
deletion from Dominant status is due
to LIDAR analysis conducted by Myrddyn Phillips resulting in a 6.5m summit
height, and with the same drop value this hill does not have sufficient prominence
to be considered for Dominant
status. Dominant total decreases by one and confirmed as 257.
No Name Stack 31.1m at SR 97567 93273
This hill was not included as a Dominant hill when the Brandy Hill group of hills was published on MappingMountains on the 03.09.18, and a Hill Reclassifications post was then published
on the 30.09.18. The hill was listed as
a Dominant based on information
received from Dave Viggers who is now one of the Vice Presidents of the
Climber’s Club, the approximate height was then revised based on the 30m spot
height that appears on Ordnance Survey 1:25,000 Explorer maps, however this
hill is adjoined to the mainland and is not tidal which meant that its P30
status was always debatable. This hill’s
deletion from Dominant status is due
to LIDAR analysis conducted by Myrddyn Phillips resulting in a 31.1m summit
height of a 2.6m bwlch height, with these values giving this hill 28.5m of
drop, which is insufficient for Dominant
status. Dominant total decreases by one and confirmed as 258.
Pen Twmp 217m at SM 98820 32984
This hill’s reclassification from Lesser Dominant to Dominant status was announced when the
Mynydd Preseli group of hills were published on Mapping Mountains on the 03.07.18, with a Hill Reclassifications post being
published on the 14.08.18. The hill was
initially classified as a Dominant
based on interpolation of bwlch contours and later reclassified to a Lesser Dominant (see below) based on the
109m spot height that appears on the area of this hill’s bwlch on the Ordnance
Survey Interactive Coverage Map hosted on the Geograph website. This hill’s reclassification back to Dominant status is due to LIDAR bwlch
analysis conducted by Myrddyn Phillips resulting in a bwlch height of 108.3m,
giving this hill 109m of drop and 50.09% Dominance. Dominant
total increases by one and confirmed as 259.
Fegla Fach 31.5m at SH 63818 15311
Fegla Fach (SH 638 153) is now listed as a Dominant hill |
The addition of this hill to Dominant status was announced on Mapping Mountains on the 25.07.18 when the Hill Reclassification post was published, however its addition as a 30-99m Twmpau and it having 30m of drop had been announced on Mapping Mountains on the 05.07.18. Prior to LIDAR analysis, an on-site visit and a survey with the Trimble GeoXH 6000 this hill was listed with 25m of drop based on the 28m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and the 3m spot height that appears on the area of this hill’s bwlch on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website. The summit height produced by 1m DTM LIDAR analysis is 31.5m, however as the high point of this hill consists of a large rock it is likely that the LIDAR technique did not model the very highest part of this rock, whilst the bwlch height produced by the Trimble GeoXH 6000 survey is 1.5m, with these values giving this hill 30.0m of drop and 95.37% Dominance. Dominant total increases by one and confirmed as 258.
Ynys
Ddu 31.9m at SM 88673 38869
The announcement of this hill’s addition to Dominant status was made on Mapping Mountains when the Mynydd Preseli group of hills were published on the 03.07.18,
with a Hill Reclassification post being published on the 04.08.18. This hill’s status as a P30 was brought to
the attention of the hill bagging community by Mick Moore, and prior to LIDAR analysis, this hill was listed with an estimated c 32m summit height based on
the small 30m uppermost contour ring on Ordnance Survey 1:25,000 Explorer
maps. The summit height produced by 2m
DSM LIDAR analysis is 31.9m and the bwlch height is 0.5m, with these values
giving this hill 31.3m of drop and 98.28% Dominance which is sufficient for
Dominant status. Dominant total increases by one and confirmed as 257.
Rhos Ymryson 324m at SN 46038 50017
The Lesser
Dominant status of this hill was announced on Mapping Mountains on the 03.06.18 when the
Rhos Ymryson group of hills was published, with a Hill Reclassification post
appearing on Mapping Mountains on the 04.06.18.
The hill was previously listed as a Dominant
hill with 50.15% dominance based on the 327m summit and 163m bwlch spot heights
that appear on the Ordnance Survey 1:25,000 Explorer map. However, as this summit height is given to
the top of a covered reservoir, and as these constructions are not accepted as
being a part of a hill’s height in this list, the summit height was
re-evaluated. As the position of the
highest natural ground at the base of the covered reservoir is given as SN
46038 50017 and as this is extremely close to where a 1062ft (323.7m) levelled
height appears on the Ordnance Survey series of Six-Inch maps which matches the
rounded up 324m summit spot height that appears on the Ordnance Survey 1:50,000
Landranger map, it is this height that is being used for that of this hill’s
summit, and when coupled with the 162.5m bwlch height derived from LIDAR analysis, these values give this hill 161m of
drop and 49.83% dominance which is insufficient for its continued status as a Dominant hill. Dominant
total decreases by one and confirmed as 256.
Bryn y Gwynt 58.2m at SH 59949 44915
The addition of this hill to Dominant status was announced on the
Mapping Mountains site on the 30.01.18, the hill was previously listed with c 29m of drop based on the
56m spot height that appears on the Ordnance Survey 1:25,000 Explorer map and
an estimated bwlch height of c 27m based on 10m contour intervals between 20m –
30m. This hill’s addition is due to analysis
conducted by Aled Williams of data produced via LIDAR resulting in a 58.2m
summit height and a 28.0m bwlch height, with these values giving this hill 30.2m
of drop and 51.89% Dominance. Dominant total increases by one and
confirmed as 257.
Carn Ysgubor 102.4m at SM 69953 24603
Carn Ysgubor (SM 699 246) has now been reclassified back into the ranks of Lesser Dominant hills |
This hill was originally listed as a Lesser Dominant and subsequently reclassified to a Dominant hill based on the result of a survey conducted with the Trimble GeoXH 6000 (see below), the adoption of OSGM15 has resulted in accurately known heights in Wales increasing by approximately 2-4cm and this has resulted in Carn Ysgubor being reclassified back to Lesser Dominant status. The announcement of this hill’s reclassification back to a Lesser Dominant hill was made on the Mapping Mountains site on 05.07.17, the hill was previously listed with 50.00% Dominance based on the 102.4m summit and 51.2m bwlch heights produced by a survey with the Trimble GeoXH 6000 conducted by Myrddyn Phillips on the 15.05.16, these values when converted to OSGM15 are 102.395m summit and 51.208m bwlch heights, with these values giving 51.187m drop and 49.99% Dominance. Dominant total decreases by one and confirmed as 256.
Carn
Ysgubor 102.4m at SM 69953 24603
Prior to OSGM15 conversion the Trimble GeoXH 6000 survey of Carn Ysgubor (SM 699 246) reclassified it from a Lesser Dominant to a Dominant hill |
The announcement of this hill’s reclassification from a Lesser Dominant to a Dominant hill was made on the Mapping Mountains site on 09.06.16 with the Hill Reclassifications post being published on the 10.06.16, the hill was previously listed with 49.50% Dominance based on the 101m summit spot height on the Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 51m based on interpolation of bwlch contouring between 50m – 55m, with these values giving this hill c 50m of drop. This hill was subsequently surveyed with the Trimble GeoXH 6000 by Myrddyn Phillips on 15.05.16, resulting in the summit height being 102.4m and the bwlch height being 51.2m, giving a drop value of 51.2m and a Dominance value of 50.00%. The survey data for this hill has subsequently been converted to OSGM15 resulting in the hill being reclassified back to Lesser Dominant status (see above). Dominant total increases by one and confirmed as 257.
Cefn 118.2m at SH 72126 00402
Cefn (SH 721 004) |
The details relating to this hill were re-evaluated on the 06.06.16, resulting in it being reclassified from a Lesser Dominant to a Dominant hill, with this being announced on Mapping Mountains on the 03.12.16 when the Tarren y Gesail group of hills were published, with a retrospective Hill Reclassifications post published on Mapping Mountains on the 28.05.17. The hill was previously listed with 48.25% dominance based on an estimated c 114m summit height taken from interpolation of its uppermost 110m ring contour, and the 59m bwlch spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map. Its reclassification is due to the 119m summit spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map and when coupled with the 59m bwlch spot height, these values gave this hill 50.42% dominance. Its reclassification has subsequently been confirmed by LIDAR analysis conducted by Myrddyn Phillips, resulting in a 118.2m summit height and a 59.0m bwlch height, with these values giving this hill 59.2m of drop and 50.08% dominance. Dominant total increases by one and confirmed as 256.
Ynys
Fach 30.8m at SM 82209 32743
Ynys Fach (SM 822 327) a marvelous hill whatever its Dominance |
The deletion of this hill from Dominant status was announced on Mapping Mountains on the 06.06.16, with the survey that resulted in this hill’s deletion being conducted on the 14.05.16, and the Hill Reclassifications post being published on Mapping Mountains on the 08.06.16, the hill was previously listed with 100.00% Dominance based on an estimated c 31m summit height and the same drop value. The hill has subsequently been surveyed using a Trimble GeoXH 6000 by Myrddyn Phillips, resulting in a 30.8m (converted to OSGM15) summit height and a 1.2m (converted to OSGM15) bwlch height, with these values giving this hill 29.6m of drop, which is insufficient for it to be considered for Dominant status. Dominant total decreases by one and confirmed as 255.
Moelfre 74.1m at SH 55830 37553
Moelfre (SH 558 375) is now reclassified from a Dominant to a Lesser Dominant hill |
The announcement of this hill’s reclassification from a Dominant to a Lesser Dominant was made on the Mapping Mountains site on 03.03.16 with the Hill Reclassifications post being published on the 04.03.16, the hill was previously listed with 50.00% Dominance based on the 74m summit spot height on the Ordnance Survey enlarged mapping hosted on the Geograph website and an estimated bwlch height of c 37m based on bwlch contouring between 35m – 40m. This hill was subsequently surveyed with the Trimble GeoXH 6000 by Myrddyn Phillips on 23.02.16, resulting in the summit height being 74.1m (converted to OSGM15) and the bwlch height being 37.8m (converted to OSGM15), giving a drop value of 36.3m and a Dominance of only 49.00%, which is insufficient for it to retain its Dominant status. Dominant total decreases by one and confirmed as 256.
Pt.
66m 66m at SH 29957 27041
This
hill’s reclassification to a Dominant hill
was announced on the 11.02.16 when the Pen LlÅ·n group of hills was
published on Mapping Mountains, with a retrospective Hill Reclassifications
post appearing on Mapping Mountains on 19.03.17, the hill was previously listed
with 48.44% Dominance based on a 64m
map heighted summit at SH 295 266. In
recent times the Ordnance Survey larger scaled mapping has become available on
the Geograph website and this more detailed map shows a 66m summit spot height at
SH 299 270 and a connecting 32m bwlch spot height, with the subsequent drop of 34m
sufficient for this hill to qualify as a Dominant
hill with 51.52% Dominance. Dominant total increases by one and
confirmed as 257.
Bodlondeb
Wood c 57m at SH 77923 78114
The inclusion of this hill in the listing of Y Trechol – The Dominant Hills of Wales
was on the 17.12 15 via the publication on
Mapping Mountains of the hill grouping it is a part of, with a retrospective
Hill Reclassifications post appearing on the 18.02.17. The hill had previously been unclassified due
to lack of detail on the Ordnance Survey 1:50,000 Landranger and 1:25,000
Explorer maps giving only a 50m uppermost ring contour and bwlch contouring
between 20m – 30m, however with the
advent of 5m contour intervals on the Ordnance Survey enlarged mapping hosted
on the Geograph website a more detailed estimation of its drop value and
therefore its Dominance could be given, and with a drop value of c 34m based on
an estimated summit height of c 57m and an estimated bwlch height of c 23m, the
hill is now listed with a Dominance of 59.65%.
Dominant total increases by one
and confirmed as 256.
3rd
December 2015 – Mapping Mountains starts publication of Y Trechol – The Dominant
Hills of Wales.
Dominant
total
confirmed as 255.
Bryn Mawr 178.1m at SJ 25117 19054
The wooded summit of Bryn Mawr (SJ 251 190) |
The reclassification of this hill from a Lesser Dominant to a Dominant hill was due to a survey conducted by Myrddyn Phillips with the Trimble GeoXH 6000 on the 08.08.15, with its details appearing in the Carnedd Wen group of hills when published on Mapping Mountains on the 03.06.17, with a retrospective Hill Reclassifications post appearing on Mapping Mountains on 16.07.17, the hill was previously listed with 49.13% Dominance based on an estimated c 173m summit height and an estimated c 88m bwlch height, with the latter height later confirmed via an 88m spot height appearing on the Ordnance Survey enlarged mapping hosted on the Geograph website. The subsequent survey with the Trimble produced a 178.1m (converted to OSGM15) summit height, giving this hill 90m of drop and 50.53% Dominance. Dominant total increases by one and confirmed as 255.
Carreglefain 260.7m at SH 32421 41054
Carreglefain (SH 324 410) is now listed as a Dominant hill after a survey with the Trimble GeoXH 6000 |
The announcement of this hill’s reclassification from a Lesser Dominant to a Dominant hill was made on the Mapping Mountains site on 01.12.14 with the Hill Reclassifications post being published on the 20.03.17, the hill was previously listed with 48.66% Dominance based on the 261m summit spot height on the Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 134m based on bwlch contouring between 130m – 140m. This hill was subsequently surveyed with the Trimble GeoXH 6000 by Myrddyn Phillips on 24.11.14, resulting in the summit height being 260.7m (converted to OSGM15) and the bwlch height being 130.1m (converted to OSGM15), giving a drop value of 130.6m and a Dominance value of 50.08%. Dominant total increases by one and confirmed as 254.
Castell
Cricieth 49.6m at SH 50003 37733
Castell Cricieth (SH 500 377) was accepted as a Dominant hill after its introduction into the P30 ranks |
This hill was included as a Dominant hill shortly after Alex Cameron first proposed its inclusion as a new P30 in September 2014, with the hill appearing in its respective hill grouping of Moel Hebog when published on Mapping Mountains on 28.01.16 and a retrospective Hill Reclassifications post appearing on Mapping Mountains on 07.03.17. The hill had previously been unclassified as with an uppermost 30m ring contour on Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps and bwlch contouring between 10m – 20m it was deemed not to have the minimum 3om of drop required for consideration as a Dominant hill. However, the Ordnance Survey enlarged mapping hosted on the Geograph website has contour intervals at 5m and with a 48m summit spot height and an estimated bwlch height of c 18m, these values gave this hill c 30m of drop and 62.50% of Dominance. The hill has subsequently been surveyed with the Trimble GeoXH 6000 by Myrddyn Phillips on the 15.06.15 with the details relating to this survey being published on Mapping Mountains on the 27.06.15, resulting in a 49.6m (converted to OSGM15) summit height and a 19.3m (converted to OSGM15) bwlch height, giving 30.3m drop and 61.02% Dominance. Dominant total increases by one and confirmed as 253.
Llanlleiana Park 68.2m at SH 38337 94993
Llanlleiana Park (SH 383 949) is now listed as a Lesser Dominant hill |
The reclassification of this hill to a Lesser Dominant was announced on the Mapping Mountains site on 13.09.14 with the Hill Reclassifications post appearing on the 07.12.15, the hill was previously listed with 50.75% Dominance based on the 67m spot height that appears on the Ordnance Survey enlarged mapping hosted on the Geograph website and an estimated bwlch height of c 33m, with these values giving this hill c 34m of drop. This hill was subsequently surveyed with the Trimble GeoXH 6000 by Myrddyn Phillips and Alex Cameron on 07.09.14, resulting in the summit height being 68.2m (converted to OSGM15) and the bwlch height being 34.2m (converted to OSGM15), giving a drop value of 34.0m and a Dominance of only 49.85%, which is insufficient for it to retain its Dominant status. Dominant total decreases by one and confirmed as 252.
Ynys Glog 40.6m at SH 59647 39826
Ynys Glog (SH 596 398) is now listed as a Dominant hill |
The inclusion of this hill in the Dominant list took place shortly after Aled Williams first proposed it as a new P30 in early 2014, with a Hill Reclassifications post detailing its new status as a P30 appearing on the Mapping Mountains site on 05.02.14, the hill was subsequently listed in the Moelwynion group of Dominant hills when published on Mapping Mountains on 25.02.16, with a retrospective Hill Reclassifications post for its status as a Dominant hill appearing on the 07.04.17. Prior to this hill being listed as a P30 it had not been classified as contouring on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps implied that it did not have the required minimum 30m of drop to be included as a P30 and therefore be considered for Dominant status. With the advent of on-line mapping and especially the Ordnance Survey enlarged mapping hosted on the Geograph website there is now greater opportunity to analyse numerical data and with a 42m summit spot height and an estimated c 8m bwlch height on this enlarged map it gave this hill c 34m of drop and 80.95% Dominance. The hill has subsequently been surveyed using a Trimble GeoXH 6000 by Myrddyn Phillips and Aled Williams on the 21.11.14 resulting in a 40.6m (converted to OSGM15) summit height and a 7.9m (converted to OSGM15) bwlch height, giving 32.7m of drop and 80.44% Dominance. Dominant total increases by one and confirmed as 253.
Ynys
Berfedd 42.9m at SH 59943 39865
The wooded and rocky slopes of Ynys Berfedd (SH 599 398) |
This hill was included in the Dominant list shortly after Aled Williams first proposed its inclusion as a new P30 in early 2014, with a Hill Reclassifications post detailing its new P30 status appearing on Mapping Mountains on 05.02.14, the hill then appeared in the Moelwynion group of Dominant hills when published on Mapping Mountains on 25.02.16, with a retrospective Hill Reclassifications post for its status as a Dominant hill appearing on the 06.04.17. The hill had previously appeared in the sub list that accompanied the original Welsh P30 lists when published on Geoff Crowder’s v-g.me website, with map contouring on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps implying that it did not have the required minimum 30m of drop to be included in the main list. However, the Ordnance Survey enlarged mapping hosted on the Geograph website has a 43m summit spot height, and with an estimated c 6m bwlch height this gave the hill c 37m of drop and sufficient Dominance to be included in Y Trechol – The Dominant Hills of Wales. The hill has subsequently been surveyed using a Trimble GeoXH 6000 by Myrddyn Phillips and Aled Williams on the 21.11.14 resulting in a 42.9m (converted to OSGM15) summit height and a 6.8m (converted to OSGM15) bwlch height, giving 36.1m of drop and 84.06% Dominance. Dominant total increases by one and confirmed as 252.
Ynys
Hir 37.3m at SH 56695 39693
The wooded surrounds of Ynys Hir (SH 566 396) |
This hill’s inclusion as a new P30 and Dominant hill was announced on Mapping Mountains on 02.02.14 with the Hill Reclassifications post being published on the 26.02.17, the hill was previously unclassified as detail on a variety of different scaled Ordnance Survey maps implied that it did not have the minimum 30m of drop required to be considered for Dominant status. This hill was subsequently surveyed with the Trimble GeoXH 6000 by Myrddyn Phillips and Aled Williams on the 01.02.14, and it was Aled who suggested visiting the hill and its potential as a new P30, resulting in a survey height of 37.3m (converted to OSGM15) for the summit and with an estimated bwlch height of c 3m, these values give this hill c 34m of drop and 91.21% of Dominance. Dominant total increases by one and confirmed as 251.
Ynys
Deullyn 32.6m at SM 84479 34095
This hill was added to the Dominant list shortly after its initial completion in November 2012, prior to this it was unclassified
and did not appear in the P30 list on Geoff Crowder’s v-g.me website as it was
thought not to have the minimum 30m of drop required for Dominant consideration, the advent of the Ordnance Survey
Interactive Coverage Map hosted on the Geograph website with its greater scale
and definition and importantly a 30m summit spot height meant that this hill,
which is an island, qualifies for P30 status as well as Dominant status, with a retrospective Hill Reclassifications post
appearing on Mapping Mountains on the 08.09.18.
The hill has since been analysed via LIDAR resulting in a 32.6m summit
and 2.1m bwlch height, with these values giving this hill 30.5m of drop and 93.51%
dominance. Dominant total increases by one and confirmed as 250.
Gewni 35.7m at SM 79696 23606
Gewni (SM 796 236) from the north |
This hill was added to the Dominant list shortly after its initial completion in November 2012, prior to this it was unclassified
and did not appear in the P30 list on Geoff Crowder’s v-g.me website as it was
thought not to have the minimum 30m of drop required for Dominant consideration, the advent of the Ordnance Survey
Interactive Coverage Map hosted on the Geograph website with its greater scale
and definition and importantly a 35m summit spot height meant that this hill,
which is an island, qualifies for P30 status as well as Dominant status, with a retrospective Hill Reclassifications post
appearing on Mapping Mountains on the 29.08.18.
The hill has since been analysed via LIDAR resulting in a 35.65m summit
and 0.3m bwlch height, with these values giving this hill 35.3m of drop and
99.11% dominance. Dominant total increases by one and confirmed as 249.
31st November 2012 – Compilation of hand written list completed of Y Trechol – The Dominant Hills of Wales.
Dominant
total
confirmed as 248.
Carreg
Rhoson c 30m at SM 67235 25678
THIS HILL
HAS SUBSEQUENTLY BEEN DELETED FROM DOMINANT STATUS
The islets making up Carreg Rhoson (SM 672 256) with the highest island now listed as a Dominant hill |
This hill was the second of two added to the Dominant list shortly after its initial compilation was completed with the date of 31.10.12 recorded against the two additions, prior to this it was unclassified and did not appear in the P30 list on Geoff Crowder’s v-g.me website as its uppermost 30m ring contour on the Ordnance Survey 1:25,000 Explorer map had not been spotted, the advent of the enlarged mapping hosted on the Geograph website with its greater scale and definition meant that the small 30m ring contour was easier to see and therefore this hill, which is an island, qualifies for P30 status as well as Dominant status, with a retrospective Hill Reclassifications post appearing on the Mapping Mountains site on 09.03.17. Dominant total increases by one and confirmed as 248.
Dinas
Dinlle 34.7m at SH 43676 56438
Dinas Dinlle (SH 436 564) is now listed in the ranks of Dominant hills |
This hill was one of two added to the Dominant list shortly after its initial compilation with the date of 31.10.12 recorded against the two additions, prior to this its potential inclusion as a P30 was first spotted by Chris Watson, with the hill appearing in its respective hill grouping when published on Mapping Mountains on 28.01.16 and a retrospective Hill Reclassifications post appearing on Mapping Mountains on 24.02.17. The hill had previously been unclassified with a 31m summit spot height on the Ordnance Survey 1:50,000 Landranger and bwlch contouring between 0m – 10m on this and the 1:25,000 Explorer map, these details implied that the hill did not have 30m of drop which is the minimum required for consideration to Dominant status. However, the Ordnance Survey enlarged mapping hosted on the Geograph website has contour intervals at 5m and with an uppermost ring contour of 35m and bwlch contouring between 0m – 5m it meant that this hill had sufficient prominence and dominance to be included in this list. The hill’s summit was subsequently surveyed with the Trimble GeoXH 6000 by Myrddyn Phillips and Bryn Phillips on the 26.12.13 with the details relating to this survey being published on Mapping Mountains on the 03.01.14, with the 34.7m (converted to OSGM15) summit height and a 4.1m bwlch height, with the latter ascertained from LIDAR analysis, these values give this hill 30.6m of drop and 88.22% dominance. Dominant total increases by one and confirmed as 247.
Pen Twmp 217m at SM 988
329
This hill’s reclassification from Dominant to Lesser Dominant status took place after 22.03.12 and was retrospectively reported
on Mapping Mountains with a Hill Reclassifications post on the 09.08.18. The hill had previously been classified with
50.69% Dominance based on the 217m summit spot height that appears on the
Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 107m
based on interpolation of bwlch contouring between 105m – 110m, this drop value
was amended when the Ordnance Survey Interactive Coverage Map hosted on the
Geograph website became available online, and as this scale of mapping shows a
109m spot height on the area of this hill’s bwlch this amended the drop value
of the hill to 108m and its Dominance to 49.77% and it was therefore
reclassified from a Dominant to a Lesser Dominant hill. This hill has subsequently been analysed via
LIDAR resulting in a 108.3m bwlch height and its reinstatement as a Dominant hill (see above). Dominant
total decreases by one and confirmed as 246.
Cae Quarry 70.9m at SN 50644 20918
LIDAR image of Cae Quarry (SN 506 209) |
The reclassification of this hill from Dominant to Lesser Dominant status took place after 22.03.12 and was retrospectively reported on Mapping Mountains with a Hill Reclassifications post on the 04.03.18. The hill had previously been classified with 50.00% Dominance based on the 68m summit spot height and an estimated bwlch height of c 34m, with the latter based on 10m contour intervals on the Ordnance Survey 1:25,000 Explorer map, this drop value was amended when the Ordnance Survey Interactive Coverage Map hosted on the Geograph website became available and was examined, and as this scale of mapping has 5m contour intervals for the area surrounding this hill it altered its drop value to an estimated c 31m, and its Dominance to 45.59%. The hill was subsequently analysed via LIDAR, resulting in a 70.9m summit height and a 36.1m bwlch height, with these values giving this hill 34.8m of drop and 49.04% dominance. Dominant total decreases by one and confirmed as 247.
Ynys Gron 69.4m at SH 59653 39268
The Trimble GeoXH 6000 gathering data at the highest point of what remains of Ynys Gron (SH 596 392) |
This hill was deleted from the Dominant list after 22.03.12 and was retrospectively reported on Mapping Mountains with a Hill Reclassifications post on the 05.04.17, with the hill having been excluded from the Moelwynion group of hills when these were published on Mapping Mountains on the 25.02.16. The hill had previously been classified with 52.08% Dominance based on the Ordnance Survey 96m summit spot height on the 1:25,000 Outdoor Leisure map and an estimated drop of c 50m, this was reassessed when more up-to-date on-line mapping became available that showed this hill’s summit to have been quarried. The hill has subsequently been surveyed using a Trimble GeoXH 6000 by Myrddyn Phillips on the 25.11.14, resulting in a 69.4m (converted to OSGM15) summit height and a 44.3m (converted to OSGM15) bwlch height, with these values giving this hill 25.1m of drop, which is insufficient for it to be considered for Dominant status. Dominant total decreases by one and confirmed as 248.
Geirth
Mawr 57.4m at SH 53511 39363
LIDAR image of Geirth Mawr (SH 535 393) |
The deletion of this hill from Dominant status took place after 22.03.12 and was reported on Mapping Mountains with a Hill Reclassifications post published on the 21.02.17, with the hill having been excluded from the Moel Hebog group when these were published on the 28.01.16. When the original 30-99m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was included in the Hills to be surveyed sub list, as it was considered not to meet the criteria then used for the main P30 category. When the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with an estimated c 30m of drop, based on an estimated c 58m summit height, based on interpolation of 10m contouring and the 28m bwlch spot height that appears on the Ordnance Survey 1:25,000 Explorer map, resulting in a dominance value of 51.72%, which was sufficient for Dominant status. The details for this hill were re-assessed when the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map became available online. This mapping had many spot heights not on other publicly available Ordnance Survey maps and for this hill it had a 56m summit spot height, resulting in its drop value being amended to 28m, which is insufficient for continued Dominant status. The hill has now been analysed via LIDAR, resulting in a 57.4m summit height and a 27.9m bwlch height, with these values giving this hill 29.5m of drop. Dominant total decreases by one and confirmed as 249.
11th
April 2011 – Started compilation of hand written list of Y Trechol – The Dominant
Hills of Wales.
Dominant
total
confirmed as 250.
23rd
April 2009 – Criteria established and first hill purposely bagged that met the
criteria of Y Trechol – The Dominant Hills of Wales.
Dominant
total
confirmed as 250.
Myrddyn Phillips (August 2017)
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