Sunday 2 June 2019

Mapping Mountains – Hill Reclassifications – Hewitts


Mynydd Graig Goch (SH 497 485) – SubHewitt reclassified to Hewitt

This is one in a series of retrospective Hill Reclassification posts that detail hills whose status has altered in the listing of the Welsh Hewitts (an acronym for Hill in England, Wales or Ireland over Two Thousand feet high).  These reclassification posts will give details of hills where I have had direct association with their change of status, and they will tie in with a forthcoming Change Register giving detail to this list and its alterations since first publication.

The listing of Welsh Hewitts was published in booklet format by TACit Tables in February 1997 and entitled The Hewitts and Marilyns of Wales.  This list evolved out of The Absolute Summits of England and Wales which were known as the Sweats (an acronym for Summits in Wales and England Above Two-thousand FEET) and which was published by Cicerone Press in 1992 in the book entitled The Relative Hills of Britain.  The list compiler for the Hewitts and the preceding Sweats is Alan Dawson.

When the Welsh Hewitts list was published in booklet format there were 137 qualifying hills listed with their criteria being any Welsh hill at or above 2000ft (609.6m) in height with 30m minimum drop, accompanying the main list are two sub category’s entitled SubHewitts, with the two sets of criteria being any Welsh hill at or above 600m and below 2000ft (609.6m) in height that have a minimum drop of 30m and any Welsh hill at or above 2000ft (609.6m) in height with 20m or more and below 30m of drop.

The Hewitts and Marilyns of Wales by Alan Dawson

The details for the hill reclassification appear below:

The name of the hill is Mynydd Graig Goch, and it is adjoined to the western end of Crib Nantlle (Natlle Ridge) which forms a part of the Moel Hebog group of hills, and it is positioned with the A487 road to its west and the A4085 road and the village of Beddgelert towards its east, and has the towns of Porthmadog towards its south-east and Caernarfon towards its north.

Mynydd Graig Goch (SH 497 485)

Prior to this hill’s reclassification to Hewitt status it was listed as a SubHewitt with an estimated c 71m of drop based on the 609m summit spot height that appeared on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps of the day and an estimated bwlch height of c 538m. 

As its 609m summit spot height was near the benchmark height of 2000ft (609.6m) it was prioritised for a GNSS survey by John Barnard who approached Leica Geosystems suggesting that a joint survey with the fledgling team of G&J Surveys could take place.  Leica Geosystems were enthusiastic for this to happen and the hill was surveyed on the 11th August 2008.

Mynydd Graig Goch was surveyed by James Whitworth of Leica Geosystems using a Leica SmartRover 1200 and two hours of data were gathered in conditions which can be described as being wet, resulting in a summit height at that time of 609.72m.  These data were reprocessed by Ordnance Survey resulting in a summit height of 609.75m which when converted using OSGM15 results in a summit height of 609.8m, which is higher than the minimum 2000ft  (609.6m) height required for Hewitt status.

The Leica SmartRover 1200 set-up position at the summit of Mynydd Graig Goch

The reclassification of this hill from Sub-Hewitt to Hewitt status was accepted by the list author and its new classification augmented in to the listing of the Hewitts in August 2008 and its newly acquired summit height and its ramifications was announced via a press conference on the 19th September 2008.


The full details for the hill are:

Name:  Mynydd Graig Goch

OS 1:50,000 map:  115, 123

OS 1:25,000 map:  17, 254

Summit Height:  609.8m (converted to OSGM15)

Summit Grid Reference:  SH 49732 48518

Bwlch Height:  539m (as listed in the Hewitts)

Bwlch Grid Reference:  SH 50929 48808 (as listed in the Hewitts)

Drop:  71m (as listed in the Hewitts)


Myrddyn Phillips (June 2019)







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