This walk: 2016-5-15.
Chub Tor, Chubb Tor. This page concentrates on the
implications of the road sign
below which is seen on the A386 road ...... it begs the
question - is
there a tor at Chub Tor?
The page is based on visits made in January and
February 2016.
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.
Self-explanatory.
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.
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 phorographs 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.
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.
The location of the tor is not being divulged on this web site because of the
wishes of the landowners. It is on private land and is not visible from
any public path or access land.
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.
Name
Height
Page
(metres)
Hunter's Tor
193
105
Leigh Tor
185
115
Great Rock
180
80
High Tor
180
94
Puggiestone
180
152
Ravens' Tor
180
154
Gradner Rocks
178
77
John Cann's Rocks
166
107
Longtimber Tor
165
133
Chubb Tor
150
---
Raven Rock
135
153
Berra Tor
134
29
Cleft Rock
118
51
Eagle Rock
101
64
Another photograph showing the lower section of the
tor ..... 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.
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.
View of the main tor (lower outcrop): 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
large tree growing on top of it.
Where does the name "Chubb" come from - presumably
someone's name?
Researching the BT online telephone directory for "Chubb" reveals Yelverton - 0, Tavistock - 1, Plymouth - 3. Searching for the whole of Devon =
49, although this also somehow includes results for Cornwall and Somerset. There were no
results for the spelling "Chub".
An examination of the highly detailed CDROM "Mike
Brown's Guide to Dartmoor" (2001), mentions four Chubbs and eleven
Chubb marriages:
(1) square 50927876 - a miner, Stephen Chubbe, in 1691. There were 11 marriages of Chubbs
in the White Church (now Whitchurch) registers;
(2) square 53627813
- Roger Chubb of Godsworthy Farm,
where also lived John Stephens, who committed suicide in 1762 and is buried at
Stephens' Grave;
(3) square 54436620 - William Chubbe of Meawye, in a letter of attorney in 1599;
(4) square 55186845 - Francis Woodman & Elizabeth Chub; married at Longstone, in 1655.
Square 562676 records a small-holding named Chubstone near Torr Lane and a meadow named Chubstone
Mead. "Torr Fields" appears on modern maps just north of Sheepstor village.
click the loop or "continuous play" icon (if there is one)
press F11 to make more "Full Screen", remembering to press it again to
regain Normal Screen.
A movie of Chubb Tor - 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.
