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This walk: 2016-1-11. Chub Tor, Chubb Tor. This page concentrates on the implications of the road sign below ...... it begs the question - is there a tor at Chub Tor?

The 1:25,000 Ordnance Survey map shows two labels, "Chub Tor" and "Chubb Tor", close together. A postcode search shows several local properties named after Chub Tor, these being West Chub Tor, Higher Chub Tor, Middle Chub Tor, Little Chub Tor, Chub Tor Cottage and Chub Tor or Chub Tor House (Chubbtor on old maps). Along the track running past Yeoland Consols Mine (disused) is Chubbtor Cottage. 

In view of all the places on Dartmoor that are named after real tors, it seems inconceivable that this tor would be "invented" or non-existent.

PLEASE NOTE -  When you step off the track or any footpath, you are on private land .....

PRIVATE LAND - Ruins of Yeoland Consols Mine, at SX 5214 6636.  There was tin mining in the area of Yeoland Farm in 1600. Yeoland mine was operating in the 1770s, likely for copper rather than tin at this time. In 1780, the isolated farmhouse in the area was converted to an alehouse, later to become the Skylark Inn. The mine presumably had mixed fortunes and traded at some point as Plymouth Wheal Yeoland and later as South Yeoland between 1848 and 1855. Yeoland Consols Mining Co. Ltd., a new company in founded 1881, employed 15 underground and 15 surface workers by 1883, produced only 16 cwt of tin, going into liquidation in 1887 and closing by 1892. Source (for some): Buckland Monachorum Parish Council: History of Clearbrook.

PRIVATE LAND - The steepness of this gully is not shown well in this photograph, it is steep! I could have used four-wheel drive, in fact I did when I climbed up the right-hand bank to the tor. walking poles and a grappling hook on a rope would have been best, especially in light rain and going through deep leaves - it was slippery. On a subsequent visit (25th January 2016), I used a long walking staff, my companion used a walking pole, and we used ropes to get back down into the gully afterwards. It was still slippery. A visit on 2nd. Feb. was used for a few measurements etc. Another visit on 15th Feb. was for taking further photographs of the lower part of the tor, similarly on 18th Feb.

BEWARE: mine shaft (fenced) .....

Zoomed view of the mine shaft.

An overview of the most prominent (and highest) rock in this area ..... probing the ground around this area with a large fire poker on 2nd Feb. indicated that this is an exposed outcrop of the bedrock, around which the soil ranged from about 2-inches to 7 or 8-inches deep in places. This indicates that this is a real tor and not a collection of loose rocks ..... this becomes more obvious when looking at the lower section of the tor below.

This is what I identified as Chubb Tor from previous photographs taken by Mike Kitchener.

Some human scale.

Geologically, this area consists of metamorphosed Upper Devonian Slate (hornfelsed by the high temperatures of the igneous granite intrusion): this was originally a sedimentary rock (Source: BGS Geology of Britain Viewer. 

This rock contains quartz - the pure form being SiO2, silicon dioxide, although there are inclusions here.  It could be part of the Kate Brook Formation(slate) which is the country rock around nearby Yelverton Rock, and hornfelsed Upper Devonian slate where it is in close contact with Yelverton Rock, the latter being a dyke-like intrusion of microgranite. Some of the rock photographs (see link below) show swirls in the rock, as though contorted by strong forces e.g. Variscan Orogeny (and in Devon and Cornwall). The many joints in the quartz are probably due to the cooling and contracting of the quartz as it �separated� from the hot magma mix, that was the pluton that formed the batholith giving rise to the granite of the Dartmoor tors. The tremendous heat of the magma upwelling affected the surrounding country rocks and resulted in an area of metamorphic aureole. Alternatively, any sub-horizontal joints could be from the off-loading of the eroding/weathering KB slate above.  The rocky swirls seen in some of the photographs suggest that the material was quite plastic/ductile when exposed to an Orogeny and could even be a zone of volcanic material swept up during the same period. Roborough Rock has also been described as a metamorphic rock, magnesium limestone. 'Proper' limestone is calcium carbonate or calcite (CaCO₃). Magnesium limestone is calcium magnesium carbonate (CaMg(CO₃)₂) and can be known as dolomite; this is formed after CaCO3 is exposed to magnesium-rich ground water.   Click here for more photographs of the rocks of the tor.

Acknowledgement: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Dartmoor National Park link about geology and land forms.

My GPS location was SX xxxxx xxxxx metres, with an elevation of 150 �3 metres: the GPS was calibrated in situ, although the area is covered with trees. The waymark on Memory Map gives the elevation adjacent to the mark (on the same "invisible contour") of 149 metres, for what that is worth. There seem to be no other outcrops further up the slope.

An outcrop further down the slope than the rock featured above, which is at the upper right of this photograph, to the right the large tree. 

Whether or not there is a tor in this area seems to be unknown to even local residents. I knocked on four doors of properties with "Chub Tor" in their name, two people answered the door and patiently explained that they did not know why the area was so-called and whether there is a tor locally. One resident has said as much on a seemingly now-defunct blog.

What defines a tor?  Basically, it is an exposure of the bedrock, that may or may not be at the top of a hill.

If this rock is 150 metres in elevation, then it is the fifth lowest tor/rock when compared to the features in Dartmoor's Tors and Rocks, by Ken Ringwood, University of Plymouth Press, 2013. The page numbers of each rock or tor is given in the table below.

Another photograph showing the lower section of the tor ..... the vertical face here is about 10 ft / 3 metres at a guess ..... it was tape-measured at 25 ft / 7.60 m from the top to the tree stump left of centre in the photograph. The angle is a somewhat under 45�; by scale drawing, if the angle to the top is 30� then the face is about 12 ft / 3.60 m above ground level at the stump.

NB - The height of this "vertical" face has now been tape-measured at 3.5 metres (11 ft. 6 inches) down to the level of the two larger sapling trees.

Another view .....

A closer view of the upper part of this lower outcrop.

Showing the proximity of the tor and the property boundary .....

As previous photograph.  Click on the image to see a larger version.

Close view of the lower outcrop vertical face ..... it seems to be composed of separate rocks and stones adhering together like a breccia formation ..... my guess at the moment is that it might be an igneous breccia associated with the heat of the intrusive pluton that was the granitic upwelling that formed much of Dartmoor.

Closer view of this exposed face - click here for more photographs of the rocks of the tor. 

View of the main tor (lower outcrop) taken from alongside the fence around the mine shaft: this shows this formation to be cracked into possibly separate rocks.  It is possible that this seemingly "friable" section of the tor is being damaged by the tree growing on top of it.

Movie clips filmed around the site .....

1:32 minutes	360� panorama, filmed from the top of the gulley wall, on the approach to the high rock of the tor.   It pans right, looking up the gulley, pauses, tilts upwards to see the top area of the gulley.  Because of the lay of the land, you cannot actually see into the gulley.  There are some hiccups in these films occasionally as I stumbled while walking around the camera tripod - the ground slopes a lot.  The video goes to the top of the main rock and then pans right, to the main tor outcrop, at 1:07 minutes.
0:36 minutes	Filmed from almost in front of the highest rock of the tor and then pans right to the lower, main outcrop of the tor.
0:21 minutes	Filmed from down and around the main outcrop, against a fence.  It pans around and finally looks left to the lower outcrop.
0:53 minutes	Filmed from in front of the highest rock, pans left to the gulley, This shows something of the steepness of the ground.
0:58 minutes	360� panorama from right above and behind the highest rock, it zooms in but shows next to nothing of the rock because it is somewhat hidden from this viewpoint, then, pans right to look up the slope and ands looking towards the highest rock again.
0:11 minutes	Filmed from the far side of the tor, away from the gulley. This is a short video panning left from the highest rock (centred at 3 seconds, just to the right of the large tree) down to the main outcrop.
0:39 minutes	Filmed from the tree stump below the vertical face of the tor, showing the cracked nature of this lower part of the tor, zooming in and out again.

From the images above, the tor appears to be composed of two distinct types of rock.  The highest part seems to be the hornfelsed Upper Devonian Slates - looking a bit like fancy quartz to me!  The lower outcrop is of a very different rock that appears to be composed of small pieces cemented in a form of decaying, large grained concrete. 

NOTES