Mapping Mountains – Hill Reclassifications – The Fours – The 400m Hills of England

Blackstone Edge (SK 050 644) – 400m Sub-Four deletion

There has been a deletion to the listing of the The Fours – The 400m Hills of England, with the summit height, col height and their locations, the drop and status of the hill prompted by Joe Nuttall who produced a summit analysis programme using LIDAR, and then by LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Blackstone Edge (SK 050 644)

The criteria for the list that this deletion applies to are:

The Fours – The 400m Hills of England.  English hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main listing of The Fours are three categories of sub hills, with this hill being deleted from the 400m Sub-Four category, the criteria for which are all English hills at or above 400m and below 500m in height that have 20m or more and below 30m of drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and the 2^nd edition of the booklet containing this list was published by Mapping Mountains Publications on the 24^th April 2018.

The Fours - The 400m Hills of England by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Blackstone Edge, and it is adjoined to the Axe Edge group of hills, which are situated in The Southern Pennines (Region 36), and it is positioned with minor roads to its north and south, the A53 road to its west and the B5053 road to its east, and has the town of Buxton towards the north.

When the 2^nd edition of the The Fours – The 400m Hills of England was published by Mapping Mountains Publications in April 2018, this hill was included as a 400m Sub-Four and listed with an estimated c 20m of drop, based on an estimated c 403m summit height and an estimated c 383m col height, with both heights based on interpolation of 5m contouring. 

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

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

LIDAR summit image of Blackstone Edge

LIDAR col image of Blackstone Edge

Therefore, the deletion of this hill from 400m Sub-Four status is due to LIDAR analysis, resulting in a 400.9m summit height and a 384.3m col height, with these values giving this hill 16.6m of drop, which is insufficient for it to be classified as a 400m Sub-Four.

 

The full details for the hill are:

Group:  Axe Edge

Name:  Blackstone Edge

OS 1:50,000 map:  119

Summit Height:  400.9m (LIDAR)

Summit Grid Reference:  SK 05031 64470 (LIDAR)

Col Height:  384.3m (LIDAR)

Col Grid Reference:  SK 04862 64358 (LIDAR)

Drop:  16.6m (LIDAR)

 

Our thanks to Ronnie Bowron for bringing the details of this hill to our attention.

For the additions, deletions and reclassifications to The Fours – The 400m Hills of England reported on Mapping Mountains since the December 2013 publication of the 1^st edition of this list by Europeaklist please consult the following Change Registers:

 

The Fours

 

The Fours – 400m Sub-Four

 

The Fours – 390m Sub-Four

 

The Fours – 390m Double Sub-Four

 

Myrddyn Phillips and Aled Williams (October 2022)