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

Calf Top (SD 664 856) – Dewey deletion

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.

Calf Top (SD 664 856)

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 deletion appear below:

The name the hill is listed by in the Deweys is Calf Top, and it is adjoined to the Ingleborough group of hills which are situated in the central Pennines of northern England, and it is positioned with the A683 and the M6 roads to its west, and has the small town of Sedbergh towards the north and the small community of Barbon towards the south-west.

This hill was included in the original 1995 Constable publication and listed with a 609m summit height which is adjoined to a triangulation pillar given the flush bracket height of 609.600m in the OS Trig Database, and which appears as a spot height on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps.

As its 609m summit spot height was near the benchmark height of 2000ft (609.6m) it was prioritised for a GNSS survey and this took place on the 15^th April 2010.  The summit of this hill was surveyed by John Barnard, Graham Jackson and Myrddyn Phillips using a Leica 530 with two hours of data gathered, resulting in a summit height at the time of 609.61m.

Gathering data during the first Leica 530 survey of Calf Top

As this result was so close to the benchmark height of 2000ft (609.6m) it was decided to re-visit and gather a further four hours of data.  The second survey was conducted on the 20th May 2010 by John Barnard, Graham Jackson and Myrddyn Phillips using a Leica 530, resulting in a summit height at that time of 609.62m.  As the results from these surveys were so close to the 2000ft / 609.6m height the two data sets were sent to Ordnance Survey and were processed using their Bernese software, resulting in a summit height of 609.58m.

Gathering data during the second Leica 530 survey of Calf Top

This result was re-assessed in August 2016 when Ordnance Survey adopted their new OSTN15 / OSGM15 model which replaced their OSTN02 / OSGM02 model.  The adoption of the OSTN15 / OSGM15 model increased the known height of hills in England by an average of 2cm - 4cm, and in the case of Calf Top this resulted in its known accurate height increasing to 609.61m, which is higher than the maximum 2000ft (609.6m) height for Dewey status. 

These details were forwarded to the list author; Michael Dewey and the hill was deleted from his list in September 2016.

The full details for the hill are:

Name:  Calf Top

OS 1:50,000 map:  98

OS 1:25,000 map:  2

Summit Height:  609.61m (converted to OSGM15, Leica 530)

Summit Grid Reference:  SD 66450 85624 (Leica 530)

Col Height:  c 289m (interpolation)

Col Grid Reference:  SD 68178 86259 (interpolation)

Drop:  c 321m (Leica 530 summit and interpolated col)

Myrddyn Phillips (October 2020)