Mapping Mountains – Hill Reclassifications – Humps

Iolyn Park relocated to SH 781 758 – Subhump relocation

This is the thirty third in a series of Hill Reclassification and Summit Relocation posts that detail hills whose status or location has either been altered in the listing of the Humps (HUndred Metre Prominences) through map study and / or surveys that I have instigated, or it is the recommendation that their status is altered.

The summit of the Subhump named Iolyn Park is now relocated to the grazing field on the right in the background of this photo

The hill name used in this and forthcoming posts is that used in the listing of Humps, therefore individual names and their composition may not match those that are used in listings I am directly associated with.  However, I am of firm belief that listed hill names used by other authors should be respected when giving detail within other people’s lists, however inappropriate some hill names may be considered.

Many preceding posts detailing these alterations to the Humps are retrospective as these hill reclassifications and summit relocations were either initiated from studying the Ordnance Survey Interactive Coverage Map that is hosted on the Geograph website, or initiated from a survey with the Trimble GeoXH 6000, and for this summit relocation that affects the Humps the survey of this hill took place on the 10.10.18, with the recommendation of this summit relocation posted on the Tump Yahoo Group forum on the 13.10.18.

The listing of Humps was published in book format by Lulu in 2009 and entitled More Relative Hills of Britain, its author; Mark Jackson gives credit to a number of people who contributed toward the formation of this list, these include; Eric Yeaman, Alan Dawson, Clem Clements, Rob Woodall, Bernie Hughes, Pete Ridges and others.  When the list was published in book format there were 2987 Humps listed with their criteria being any British hill that has 100m or more of drop, accompanying the main list is a sub category entitled Subhumps, with the criteria being any British hill that has 90m or more and below 100m of drop.

More Relative Hills of Britain by Mark Jackson

The details for the summit relocation appear below:

There has been a summit relocation to the listing of the Humps (HUndred Metre Prominences) instigated by a survey with the Trimble GeoXH 6000 conducted by Myrddyn Phillips and which took place on the 10.10.18.

This summit relocation applies to two summits that also have a third adjoining summit all of similar map height that are orientated north to south with a northern, central and southern summit.  These three summits and their map details appear below:

Northern summit:  130m spot summit positioned at SH 78114 75813

Central summit:  130m ring contour positioned at SH 77799 75564

Southern summit:  130m ring contour positioned at SH 77584 75224

Mark Jackson gave the following details to these summits when he first collated the list of Tumps:

Northern summit:  Iolyn Park NE Top with 130m summit at SH 781 758 with c 34m of drop

Central summit:  not listed

Southern summit:  Iolyn Park with c 131m summit at SH 776 752 with c 97m of drop

The two hills listed in the original Tumps match those that Myrddyn Phillips listed in the original list of Welsh P30 hills that superseded the Tumps by a number of years.  The details in the Tumps were amended on the 25.11.12 and 19.11.13 resulting in the following:

Northern summit:  not listed

Central summit:  Iolyn Park with 130m summit at SH 777 755 with 96m of drop

Southern summit:  Gorse Hill with 130m summit at SH 775 752 with 33m of drop

Therefore at the time of the Trimble GeoXH 6000 survey on the 10.10.18 the Subhump was listed as Iolyn Park with a 130m summit positioned at SH 777 755 with 96m of drop.

These three summits were surveyed using the Trimble GeoXH 6000 resulting in the following:

Northern summit:  129.073m summit at SH 78116 75814

Central summit:  128.446m summit at SH 77790 75561

Southerly summit:  128.459m summit at SH 77584 75224

The Trimble GeoXH 6000 set-up position at the northerly summit which is now the relocated summit of the Subhump

The Trimble GeoXH 6000 set-up position at the central summit which was the old summit of the Subhump

The Trimble GeoXH 6000 set-up position at the southerly summit which was originally listed in the Tumps with c 97m of drop

The Subhump is listed under the name of Iolyn Park; this name appears on contemporary Ordnance Survey maps adjacent to land where the southern summit is situated.  However, research via the Tithe map and local enquiries with the owner of the Gorse Hill Caravan Park has resulted in the following names:

Northern summit:  Cae Alen (Tithe map)

Central summit:  Bwlch Mawr (Tithe map and local enquiry)

Southern summit:  Bryn Eithin (English map name and local enquiry)

These three summits are adjoined to the Carneddau range of hills and they are situated overlooking the Afon Conwy to the east and the B5106 road to the west, and have the town of Conwy towards the north.

The summit relocation of the Subhump was accepted and its new summit position augmented in to the listing of the Humps on the 31.10.18.

The full details for the hill are:

Name:  Iolyn Park (as listed in the Humps)

OS 1:50,000 map:  115

OS 1:25,000 map:  17

Summit Height:  129.0m (as listed in the Humps, with the Trimble survey giving 129.1m)

Summit Grid Reference:  SH 781 758 (as listed in the Humps, with the Trimble giving SH 78116 75814)

Bwlch Height:  34m (as listed in the Humps, with LIDAR giving 34.8m)

Bwlch Grid Reference:  SH 776 740 (as listed in the Humps, with LIDAR giving SH 77629 74003)

Drop:  95m (as listed in the Humps, with Trimble summit and LIDAR bwlch giving 94.3m drop)

Myrddyn Phillips (February 2019)