Friday, 24 April 2020

Mapping Mountains – Hill Reclassifications – The 500-Metre Tops of England and Wales – Deweys

Bryn-llus (SJ 085 408) – Dewey addition

This is one in a series of retrospective Hill Reclassification posts that detail hills whose status has altered in the listing of the Deweys and where I have had direct association with the status change.  These posts will tie in with a forthcoming Change Register giving detail to this list and its alterations since publication in the Mountain tables book.

Bryn-llus (SJ 085 408) during the Leica 530 survey that confirmed this hill's Dewey status

The 500-Metre Tops of England and Wales are affectionately known after their hill list compiler; Michael Dewey.  This list mixes metric and imperial height in its criteria to bookend up to the 2000ft height band and takes in all hills in England, Isle of Man and Wales that are 500m and above and below 2000ft (609.6m) in height that have 30m minimum drop.

This list formed one of a number of lists that appeared in the Mountain tables book published by Constable in 1995 and at the time of publication comprised 373 hills with 164 in England, 5 in the Isle of Man and 204 in Wales.  The Deweys have undergone extensive revision since first publication with the initial stages forming the basis of this revision given below:

1995    Mountain tables published by Constable with 373 hills listed as Deweys.

April 2000    Strider (LDWA quarterly booklet) publishes contact details for David Purchase and Myrddyn Phillips who have found and list 24 and 14 possible new 500m tops respectively.

It was expanded versions of the above two lists that formed the basis of the next publication:

25th May 2000    List of Possible 500 Metre Tops by Michael Dewey listing 44 hills.

David Purchase expands his Additional Dewey 500m Hills and Myrddyn Phillips produces lists of English 500m hills to measure and Welsh 500m hills to measure.

These lists formed the basis of the next publication:

29th June 2000    Possible/Probable 500’s by Michael Dewey listing 77 hills.  Michael adopts following protocol; if one person proposes that a top should qualify as a 500 by personal survey, and is then confirmed by a second person, it should then be promoted to the main list.

April 2002    The 500+ Tops of England and Wales – The ‘New Deweys’ published in the Strider booklet and listing 66 new qualifying hills.

25th May 2006    Rob Woodall republishes Michael’s main and possible/probable lists on the RHB Yahoo group file database. 

Mountain tables by Michael Dewey

The details for this addition appear below:

The name the hill is listed by and its composition in the Deweys is Bryn-llus, and it is adjoined to the Y Berwyn group of hills which are situated in the south-eastern part of north Wales, and it is positioned with the A5 road to its north and the B4401 road to its west, and has the town of Corwen towards the north north-west.

The remains of Liberty Hall on Bryn-llus

This hill was not included in the original 1995 Constable publication, but with a 549m summit spot height and a 519m bwlch spot height that appear on the Ordnance Survey 1:25,000 Explorer map, this hill has a minimum of 30m of drop according to contemporary Ordnance Survey maps and therefore was an automatic entry to the listing of Deweys. 

Extract from the Ordnance Survey 1:25,000 Explorer map

The above was noted by Myrddyn Phillips and these details were forwarded to the list author; Michael Dewey and the hill was added to the list on the 3rd May 2000. 

Graham Jackson and John Barnard at the bwlch of Bryn-llus during the Leica 530 survey

As the 30m drop value is the minimum required for qualification to the Deweys list this hill was prioritised for a GNSS survey and this took place on the 26th January 2010.  The summit and bwlch of this hill were surveyed by John Barnard, Graham Jackson and Myrddyn Phillips using a Leica 530 with 60 minutes of data gathered at each point.  The survey resulted in a 547.8m summit height and a 516.1m bwlch height, with these values giving this hill 31.7m of drop and this hill’s retention as a Dewey.  

The full details for the hill are:

Name:  Bryn-llus

OS 1:50,000 map:  125

OS 1:25,000 map:  255

Summit Height:  547.8m (Leica 530)

Summit Grid Reference:  SJ 08564 40894 (Leica 530)

Bwlch Height:  516.1m (Leica 530)

Bwlch Grid Reference:  SJ 09433 40520 (Leica 530)

Drop:  31.7m (Leica 530)

Myrddyn Phillips (April 2020)

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