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

Priddellau (SN 854 677) – 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.

At the summit of Priddellau (SN 854 677)

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:

25^th 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:

29^th 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.

25^th 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 in the Deweys is Priddellau, and it is adjoined to the Elenydd group of hills which are situated in the central part of Wales, and it is positioned with the B4343 road to its west and the A470 road to its north-east, and has the Claerwen Reservoir to its south and the Penygarreg Reservoir to its east, and the town of Rhaeadr Gwy (Rhayader) towards the east.

This hill was not included in the original 1995 publication, but with a 533m summit spot height and a 503m 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 detail was noted by David Purchase and Myrddyn Phillips who worked independently but also exchanged all data.  These details were forwarded to the list author; Michael Dewey and the hill was added to the list on the 3^rd May 2000.

Extract from the WalkLakes website

As people became interested in the Deweys and visiting the listed hills, it was noted that there is higher ground toward the east north-east compared to the SN 85076 67642 position of the 533m spot height on the Ordnance Survey 1:25,000 Explorer map, with a better representation of the summit position being SN 85454 67796 with the ground at this position estimated as 1m higher.  This position has subsequently been spot heighted as 534m on the WalkLakes website which hosts an interactive map originated from the Ordnance Survey Open Data programme.

The full details for the hill are:

Name:  Priddellau

OS 1:50,000 map:  135, 136, 147

OS 1:25,000 map:  187, 200

Summit Height:  534m (spot height)

Summit Grid Reference:  SN 85454 67796 (hand-held GPS via DoBIH)

Bwlch Height:  503m (spot height)

Bwlch Grid Reference:  SN 85360 68251 (spot height)

Drop:  31m (spot height summit and bwlch)

Myrddyn Phillips (April 2020)