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TRANSACTIONS
OF THE
GEOLOGICAL SOCIETY,
ESTABLISHED NOVEMBER 13, 1807.
VOLUME THE FOURTH.
Quod si cui mortalium cordi et cure sit, non tantum inventis herere, atque iis uti,
sed ad ulteriora penetrare; atque non disputando adversarium, sed opere naturam
vincere ; denique non belle et probabiliter opinari, sed certo et ostensive scire; tales,
tanquam veri scientarum filii, nobis (si videbitur) se adjungant.
.
Novum Organum, Prefatio.
avs
LONDON:
PRINTED AND SOLD BY WILLIAN PHILLIPS, GEORGE YARD, LOMBARD STREET.
; 1817.
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OFFICERS AND COUNCIL OF THE GEOLOGICAL SOCIETY,
ELECTED FEBRUARY 7, 1817.
PRESIDENT;
JOHN MAC CULLOCH, M.D. F.L.S.
VICE-PRESIDENTS,
The Hon, HENRY GREY BENNET, M.P. F.R.S, | The Right Hon. Sir JOHN NICHOLL, MP. F.R.S.
WILLIAM BLAKE, Esq. F.R.S. HENRY WARBURTON, Esq. F.R.S.
, SECRETARIES,
CHARLES STOKES, Esq. FA.& LS. | HENRY JAMES BROORE, Esq.
FOREIGN SECRETARY,
AUGUSTUS BOZZI GRANVILLE, M.D. F.L.S.
© TREASURERS,
DANIEL MOORE, Esq. F.R.A. & L.S. | JOHN TAYLOR, Esq.
COUNCIL,
ARTHUR AIKIN, Esq. HENRY HOLLAND, M.D. ERS.
THOMAS COLBY, Esq, Captain of the Royal ASHHURST MAJENDIE, Esq.
Engineers.
# WILLIAM HASLEDINE PEPYS, Esq. F.R.S.
HENRY THOMAS COLEBROOKE, Esq. F.R.S.
EDMOND WALLER RUNDELL, Esq.
Sir HENRY CHARLES ENGLEFIELD, Bart.
F.R A. & R.S. Ed. & A.P. Newc. M.R. Inst. SAMUEL SOLLY, Esq. F.R.S.
GEORGE BELLAS GREENOUGH, Esq. F JOHN WHISHAW, Esq. F.R.S. -
F.R. & LS,
WILLIAM HYDE WOLLASTON, M.D. E.R.S.
KEEPER OF THE MUSEUM AND DRAUGHTSMAN,
Mr. THOMAS WEBSTER,
TRUSTEES OF THE GEOLOGICAL SOCIETY,
GEORGE BELLAS GREENOUGH, Esq.
Sir ABRAHAM HUME, Bart. M.P.
WILLIAM BABINGTON, M.D.
ROBERT FERGUSON, Esq.
DAVID RICARDO, Esq.
SAMUEL WOODS, Esq.
ADVERTISEMENT.
THE Ediiors of the Transactions of the Geological Society
are directed to make it known to the Public, that the Authors alone are
responsible for the facts and opinions contained in their respective papers.
Geological Socicty,
July 1, 1817.
It is requested that all letlers and communications to the
Secretaries, and presents to the Society, be addressed to the House of
the Geological Society, No. 20, Bedford Street, Covent Garden, London.
Page 4 line 21 for
ib. —— 23 ——
14 —— 24 ——
17 —- 5
ib, —— 14 after
20 —— il for
28 —— 15
67 —— 8 ——
74 -—— 22 ——
106 —— 3 ——
108 lastline ——
109 line 2 ——
110 5 of note —
126 —— 25
—— —— 26 before
230 —— 16 for
290 —— 14 ——
304 —— 14 before
$11 Jastline (for
312 line 15
405 (2nd column
406 hei figures ng
AQ7 (the sections
ERRATA.
AQO rechten RON ee otha read 530
Whitby > jo csescte Whitley
north. . /steaiateveteietss south “4
Thil-whin’ss2. ose Thil
Jameson saree insert ?
Lbs wee ere a tee ee read is
Paling: 's seis as Felling
1 toda —— 3miles west of Newcastle
SONATE Ss cin ceis tee Temming.
Hesket, Newmarket —— Hesket-newmarket
water course at &c. water course. At
of Melmerby. The —— of Melmerby the
COUTSE LON aes wie — coarse
ETAVETSES!etete oa oloic-bile traverse
Often. coven ae insert is
MVE nei so creciels be ote read \evel
OL tae sat sean elena ees —— at
shames’. cyetateracitee insert the
ascendd the istance read ascend the distance
numulites........ nummulites
INCHES 3.4)s aaleienares feet
If.
III.
PV.
VI.
CONTENTS.
PART I.
Observations on the Geology of Northumberland and Durham. By
N. J. Winch, Esq. F.L.S. Honorary Member of the Geological
Society - - - - - - - p. 1
On a Whin Dyke traversing Limestone in the County of Northum-
berland. By the Hon. Henry Grey Bennet, M.P. F.R.S. Vice-
President of the Geological Society - - - - p. 102
Description of an insulated Group of Rocks of Slate and Greenstone,
in Cumberland and Westmoreland on the east side of Appleby
between Melmerby and Murton. By the Rev. William Buckland,
B.D. Professor of Mineralogy in the University of Oxford, and
Member of the Geological Society — - - - - p. 105
PART II.
Observations on the Mountain Cruachan in Argyleshire ; with some
Remarks on the surrounding Country. By John Mac Culloch,
M.D. F.L.S. President of the Geological Society, Chemist to the
Ordnance, Lecturer on Chemistry at the Royal Military Academy,
and Geologist to the Trigonometrical Survey - Sen ag es
Account of some remarkable Disturbances in the Veins of the Mine
called Huel Peever, in Cornwall. By John Williams, Esq.
Honorary Member of the Geological Society - - -p. 139
Description of the Tunnel of the Tavistock Canal, through Morwel
Down, in the County of Devon. By John Taylor, Esq. Treasurer
of the Geological Society - - - - - p. 146
b
CONTENTS.
VII. Corrections and Additions to the Sketch of the Mineralogy of Sky,
published in the Third Volume of the Transactions of the Geological
Society. By John Mac Culloch, M. iD dara S. ORE a the
Geological Society, &c. &c. - p. 156
VIII. On the Strata in the Neighbourhood of Bristol. By Richard Bright,
M.D. Member of the Geological Society. With Notes, extracted
from the Communications of George Cumberland, Esq. Honorary
Member of the Geological Society - - - - p. 193
Note on Magnesian Breccia. By Henry a Ene. Vice-
President of the Geological Society ~ - p. 205
IX. On the Magnesian Limestone and Red Marle or Sandstone of the
Neighbourhood of Bristol. By W.H. Gilby, M.D. - p. 210
X. On the Strata at Whorlbury Camp, in Somersetshire. By George
Cumberland, Esq. Honorary Member of the Geological Society pp. 216
XI. Observations on the Hill of Kinnoul, in Perthshire. By John
Mac Culloch, M.D. F.L.S. Biesident of the Geological Society,
&c. &e. - - - - . - - p. 220
XII. Account of some attempts to ascertain the angles of the Primitive
Crystals of Quartz and of the Sulphate of Barytes, by means of the
reflecting Goniometer, together with practical reasons for presuming
that the admeasurements assigned by Hauy to several varieties of
the parallelopiped and of the octohedron are inaccurate. By William ~
Phillips, Member of the Geological Suciety - = 2 = pede
XIII. On the Measurement, by the reflecting Goniometer, of certain primi-
tive Crystals ; with Observations on the methods of obtaining them
by mechanical division along the natural joints of Crystals. By
William Phillips, Member of the Geological Society - p. 241
XIV. Supplementary Observations on Quartz Rock, made in 1814. By
John Mac Culloch, M.D. F.Z.S. ‘Penton of the Geological
Society, &c. &c. - - - - - - p. 264
XV. Description of a series of Specimens from the Plastic Clay near
Reading, Berks. With Observations on the Formation to which
those Beds belong. By the Rev. William Buckland, B.D. Member
of the. Geological Society, and sister of Mineralogy in the
University of Oxford - - - 2.) p. 277
CONTENTS.
XVI. On some Beds of Shell Marle in Scotland. By Henry Warburton,
Esq. F.R.S. Vice-President of the Geological Society - . p. 305
XVII. Geological Remarks on the Vicinity of Maestricht. By the Rev.
W.E. Hony, Fellow of Exeter Shee i ahs Member of the
Geological Society - - - - p-310
XVIII. On the Parallel Roads of Glen Roy. By John Mac Culloch,
M.D. FLL.S. President of the Geological Society, &c. &c. - p- 514
XIX. On a Shifted Vein occurring in Limestone. By John Mac Culloch,
M.D. F.L.S. President of the Geological Society, &c. &c. - p. 393
XX. Luxplanation of a Supplementary Plate to the Paper on Vegetable
Remains preserved in Chalcedony, printed in the Second Volume of
the Transactions of the Geological Society. By John Mac Culloch,
M.D. F.L.S. President of the Geological Society, &c. &c, = p. 3
XXI. On a peculiar Disposition of the Colouring Matters in a Schistose
Rock. By John Mac Culloch, M.D. F.L.S. President of the
Geological Society, &c. &e. - - - - - p.399
XXII. Memoranda relative to the Porphyritic Veins, &c. of St. Agnes in
Cornwall, By the Rev, J.J. Conybeare, Member of the Geological
Society - . - - - - - -p. 401
XXIII. On the Stream Works of Pentowan. By Edward Smith, Esq. p. 404
XXIV. Observations respecting the Limestone of Plymouth, extracted from
two Letters, dated September 26, 1814, and January 19, 1815,
addressed to Henry Warburton, Esq. Secretary. By the Rev.
Richard Hennah, junr. Chaplain to the Forces at Plymouth p. 410
XXV. Description of the Paramoudra, a singular fossil body that is found
in the Chalk of the North of Ireland ; with some general Obser-
vations upon Flints in Chalk, tending to illustrate the History of
their kormation. By the Rev. William Buckland, B.D. Member
of the Geological Society, and iad of Mineralogy in the
University of Oxford - - - p.413
XXXVI. Notice of Fossil Shells in the Slate of Tintagel. By the Rev.
J. J. Conybeare, Member of the Geological Society - p. 424
XX VII. Notice of some peculiarities observed in the Gravel of Litchfield.
By Arthur Aikin, Esq. Member of the Geological Society, and
Secretary to the Society for the Encouragement of Arts, Manu-
Sactures, and Commerce - - - . - p. 426
CONTENTS.
XXVIII. Analysis of one hundred parts of a dark Bituminous Limestone,
from the Parish of Whiteford, in Flintshire, Vth Wales. By
Edward Daniel Clarke, LL.D. Professor of Mineralogy in the
University of Cambridge, and Honorary Member of the Geological
Society - - - - - - - p. 430
X XIX. Barometrical Measurements. By William Allen, Esg. F.R.S.
and Samuel Woods, Esq. Members of the Geological Society - p. 434
XXX. Notice concerning the Shropshire Witherite. By Arthur Aikin,
Esq. Member of the Geological Society, and Secretary to the Society
Jor the Encouragement of Arts, Manufactures and Commerce p- 438
XX XI. Extracts from the Minute Book of the Geological Society - vp. 443
List of Donations - - - - - - - p. 451
Index = = - - = - * - p.459
I. Observations on the Geology of Northumberland and Durham.
By N. J. WINCH, Esq.
HONORARY MEMBER OF THE GEOLOGICAL SOCIETY,
Read March 18th, 1814.*
CoNSIDERING the great importance of the coal and lead mines,
and of the quarries of Northumberland and Durham, and the oppor-
tunities which they offer to geological research, it is rather singular
that no history of the physical structure of these counties has yet
been laid before the public. It is however well known that much
interesting information on these subjects has long been accumulating
and is widely diffused among the professional conductors of the
mines. I have endeavoured in the following paper to combine
some of these scattered materials with the substance of my own
observations, and to give a general outline of the several formations
that compose our district. I have added short descriptions of the
principal rocky strata belonging to these formations, and catalogues
of such of their metallic ores, crystallized minerals, and organic re-
mains, as have come under my notice.
_* This paper was read at the meetings of the Society six months before the publication
of the sketch of the same district by Dr, Thomson. See Annals of Philosophy, for
November and December, 1814.
VOL. 1¥. A
“ Mr. N. J. Wincu on the Geology of
I. Red Marl or Sandstone.
In the south-eastern part of the county of Durham a series of
strata occurs, among which a fine grained sandstone of a brick-rell
colour, effervescing with acids, predominates. This rock may be
seen in the bed of the Tees at the distance of more than a mile west
of Croft bridge; thence it follows the course of the river to the sea,
and may be traced at some little distance from its northern bank
through Hurworth, Nesham, Sockburn, &c. beyond the town of
Stockton, forming rocks on the sea shore between Seaton and Hartle-
pool. Opposite Sockburn, Mr. Allen of Grange, lately bored in
search of coal to the depth of 118 fathoms, without passing through
these beds; and at Dinsdale, situated on the northern bank of the
Tees, three miles and a half north-east of Croft bridge, in. the year
1789, the late General Lambton. penetrated to the depth of 74
fathoms without better success. I have obtained five sections of the
workings at Dinsdale, and have communicated them, together with the
present paper, to the Society. The strata are numerous, and consist
(as far as one can judge from the miner’s language) of white, grey,,
or red sandstone with occasional partings of a more compact nature,,
red or blue shale, coaly matter in thin layers, and gypsum in nodules,
or in beds; the latter are mentioned in one case as. being three feet:
in thickness. ‘The lowest bed in the two deepest workings was: a:
strong white rock of a calcareous nature.
I should not have inserted these rude sections in the appendix (No. 1),
to this paper had it not been for an opinion prevailing in Yorkshire,
that coal will be found among these measures, and I hope by the.
publication of this document: to prevent. the future waste of capital:
on similar trials.
Northumberland and Durham. 3
’ From one of these bore-holes, at a place called Woodhead, near
the Tees, a sulphuretted water issued, similar to the Harrowgate spa.*
It arose from a bed of blue stone lying beneath a bed of gypsum at
the depth of nineteen fathoms two feet six inches from the surface.
Another sulphuretted spring rises from similar strata at Croft on the
south side of the Tees, where baths have been erected for medical
purposes. )
There can be little doubt that the sandstone we have been de-
scribing is analogous to that extensive formation of the same sub-
stance and colour which is found in Nottinghamshire to the west of
the magnesian limestone, and it probably may be traced in continuity
from the banks of the Tees through Yorkshire into the neighbour-
ing county.
Il. Magnesian Limestone.
_ To the north-west of the red sandstone the Magnesian’ or Sunder-
land limestone is found. In the cliffs at Cullercoats in Northumber-
land, a dyke well known by the name of the xinety fathom dyke, is
seen dislocating the coal-measures, and passing into the sea. Here”
is the northern extremity of the western boundary of the magnesian
limestone. A few masses again occur among the rocks of sandstone
and slate-clay, upon which Tynemouth castle stands; but it is on
_* Mr. Peacock of Darlington published the following analysis of this water. in a
pamphlet on the medical virtues of the spring.
Contents in 1 quart. . Carbonate of Lime .......... 0200000 c eee eees ..Grains 1.2
SEU DHGE. Of CAINE Vets, asin. uis aot a eSruoems sonery Sasha ouad ord 25.
Camiguin Mal Gags, cee ede e ree cee
Sulphuretted Hydrogene, containing 24 eae of Silphur. 8.32
Azotic: Gags. sescn fhe «ete h} 19. sidai@h..OEeh... eG rains ts
Specific gravity of the water 1.016. Temperature at the well 8° above that of the adjoin-
ing springs.
AQ
4 Mr. NJ. Wincn on the Geolory of
the coast in the neighbourhood. of South Shields in the county of
Durham that this formation first becomes extensive. From this
point it swells into a range of low round-topped hills, and.is seen
stretching towards the south-west, protruding into the Coal-field,
and forming an undulating line by Cleadon, Boldon, Clacks Heugh
upon the Wear near Hilton castle, Painshaw, Houghton-le-Spring,
Sherburn, Coxhoe, Ferry hill on the turnpike road leading from
Durham to Darlington, Merrington, Eldon, Brussleton, Morton,
Langton, and Sellaby, till it reaches the Tees below Winston bridge
thirty miles west-south-west of that river’s junction with the sea, and
forty-four miles from the Tyne at South Shields. The sea coast
ferms its eastern boundary for twenty-seven miles and a half from ©
the Tyne to the rocks of Hartlepool, and the red sandstone already
mentioned from Hartlepool to the termination of that rock west of
Croft bridge.
The same bed is afterwards continued through Yorkshire, Derby-
shire and Nottinghamshire, to the neighbourhood of Nottingham,
where it suddenly terminates. |
Of the hills of this rock, protruded into the Coal-field, Painshaw
near Lambton appears to be the highest, being probably not less
than 400 feet above the level of the sea. Kirk Merrington, situated
on one of these hills may also be seen to a considerable distance. .
The quarry at Whitby near Cullercoats affords the geologist an
excellent opportunity of ascertaining that the magnesian limestone
overlies the coal-measures, and that the latter were consolidated
before the limestone. was. deposited upon them. I shall therefore
describe that curious spot. —
A hollow space formed like a basin or trough is filled with the
limestone.*. ‘The length of this from east to west is about a mile ;
* Plate 4, fig. I,
Northumberland and Durham. 5
the breadth from north to south four hundred yards, the depth seventy
feet. The beds pass over the ninety-fathom-dyke ; which has oc-
casioned in them no confusion or dislocation ; so that there can be
little hazard in stating that the beds of the magnesian limestone
belong to a more recent formation than those of the Coal-field. The
limestone has been quarried across its whole breadth, and a nume-
rous set of thin strata are thus exhibited to view. At the surface
loose blocks of bluish grey coralloid limestone, the produce of the
lead mine district are found imbedded in the soil. Three or four of
the uppermost strata of the quarry are of white slaty limestone,
which being nearly free from iron, burns into a pure white lime.
Below these an ash-grey fine grained stratum is met with, which
strongly resembles a sandstone, and seems to contain nearly as much
iron as the ferri-calcite of Kirwan, becoming magnetic by the action
of the blow-pipe: it produces a brownish yellow lime, less esteemed
for agricultural purposes than the former. The beds next in
succession are of an ash-grey colour, are compact in texture, and
conchoidal in fracture: these afford a buff coloured lime, which
sells for nearly the same price as the white. Near the bottom.of
the quarry the limestone alternates with shale ; the whole rests upon
a stratum of shale on the southern side, and upon a thick bed of
sandstone on the northern. ‘The shale has been cut through to a
considerable distance from the kilns in the direction of North
Shields, for the purpose of laying a rail-way to the Tyne. The
thickness of the limestone strata varies from three or four inches
to as many feet. Small strings of galena have been found here,
and, in one of the strata that was walled up when I visited the
quarry, a few organic remains have been noticed.
The stone intended to be burnt is detached from the rock by the
agency of fire, during which process those portions which contain
6 Mr. N. J. Wincu on the Geology of
iron become of a brick-red colour. Considerable quantities of fuel
are found necessary at the kiln, and some parts of the rock are too
apt to vitrify in the process, an accident to which the crystalline
limestone of Sunderland is not liable.
Along the coast of Durham from Shields to Hartlepool, the
uppermost bed frequently consists of a species of breccia, the cement
of which is a marl-like substance consisting chiefly of magnesian
carbonate of lime, and with this breccia wide chasms or interrup-
tions in the cliff are filled. The next strata are thin and slaty, but
lower down the stratification becomes less distinct. The colour
of this rock is then light hair brown, the texture crystalline and
cellular, from which latter cause it strongly resists the stroke of the
hammer. The slaty variety occurs at Bolden hills, Marsden rocks,
and numerous other places; its colour is white inclining to buff;
dendritical marks may be found between the thin layers into which
it easily breaks ; and in Marsden lane and on the sea coast a flexible
kind has lately been noticed by Mr. Nichol. In the neighbour-
hood of Sunderland* the brown variety is generally quarried ; it
partakes of the nature of swinestone, and from containing some
inflammable matter requires only a small quantity of coal to be
reduced to lime. That worked at Denton, not far from the Tees,
and analyzed by the Rev. J. Holme, is, I suspect, of this quality,
for he mentions bitumen, as one of its constituents; whereas Sir
H. Davy takes no notice of that substance in the rocks of Eldon
and Aycliff. (
* The exportation of lime from Sunderland is chiefly to Scotland, and amounts to from
forty-two to forty-five thousand chaldrong of 36 bushels each, annually.
fe Northumberland and Durham. 4
Analysis of 100 parts of Limestone.
By the Rev. J. Holme. By Sir H. Davy.
From Denton. From Eldon. From Aycliff,
pCarhonate'of Lime) .r. 0/5. rei." F sof GS Sie . sherk.td + « DBT aactd totes 48.9
of Magnesia’ 5... js: crite oat SA le Sh ey Atr nis joisbe AES Dei eg alc, sleka 46.6
“Alumina, Red Oxide ofTrom,)” ©" 9.95 | Tron ..+..:2. SM letciten as 1.66
and Bitumen.
DAW DEET? . Foy Site c.0. Maresh plates oct EDN > FOG os ed, | Bs cp ttcre'e 0 6 2.8
100.
In a quarry at Hartlepool I have noticed a stratum of hard white
eolite, the grains composing it being about the size of a mustard’
seed; but, unlike the Ketton and Riflington roe-stones, it: contains
no shells or marine exuvie. TI have found at the same place:a bed:
of pale buff coloured limestone of an earthy fracture, punctured’
with holes: not larger than a needle’s point. The ornamental parts
of the old exchange at Newcastle were carved’ out of these two
varieties of stone.
The four lowest strata. of Mr. Goodchild’s quarries at Pallion
near Sunderland, constitute another variety. Its colour is a dirty
light brown; but taking a tolerably good polish it is sold as a
marble. In lustre and hardness it resembles a stalagmite ; it is met
with at the depth of eleven fathoms from the surface.
In Castle Eden Dean: there are cliffs of this rock well worthy
of notice; and the perforated rocks at Marsden and Hartlepool,
and the caverns at the latter place, at Black-hall. near Easington,
and on the coast near Monk Wearmouth, deserve the attention
of the geologist. These curious and picturesque objects appear to
have been formed at no very distant date by the action at the sea,
which has dissolved and washed out the soft. marly limestone, with:
8 Mr. N. J. Wincu on the Geology of
which the cavities of these rocks were once filled. From this cause
the promontory, on which Hartlepool stands, is rapidly crumbling
away. ,
It is well ascertained that the magnesian limestone of this district,
as is the case with that of Derbyshire and Yorkshire, rests upon
the coal-measures. No coal mine however has yet been won in
Northumberland or Durham, by sinking a shaft through the lime-
stone, although the workings of some collieries situated on its
western boundary have been carried underneath it. It is therefore
a matter of great importance to those who have royalties within its
limits to know under what thickness of limestone the coal measures
are buried ; whether after passing under the limestone they continue
to dip at the same angle as before, and whether the quality or
thickness of the coal-seams is then altered.
I have not been able to ascertain what is the total thickness of
the limestone ; but at Hart, near to Hartlepool, a bore-hole was
made in it to the depth of 52 fathoms, without penetrating through
it. This spirited undertaking was then frustrated from the per-
foration being filled with sand and water. At Pallion, a little to
the west of Sunderland, the limestone was only 12 fathoms thick,
below which the coal measures were bored through to the depth of
140 fathoms without finding a coal seam worth working.
Along the coast of Durham from Shields to Hartlepool! the lime-
stone strata dip to the south-east. At Chapted main near South
Shields, the coal measures, although approaching the limestone, rise
towards the sea, in conformity to their direction on the north side
of the Tyne; but at Painshaw, New bottle, Rainton, &c. they dip
to the south-east, the limestone being there protruded into the
Coal-field beyond the prolongation of that line, from which the
coal measures that are without covering begin to rise in an eastern
Northumberland and Durham. 9
direction. It appears therefore that their dip is not affected by the
limestone. It is a circumstance however too well ascertained to
admit of a doubt, though difficult to be accounted for, that the coal
is deteriorated in quality where covered by the limestone.
Galena is the only metallic ore that I have observed in this lime-
stone. It has been found in small strings at Whitby quarry,
Clacks-heugh Blackhall-rocks, Ryehope, and amongst the rocks
below Tynemouth castle: at the latter place calcareous spar is the
matrix.
The crystallized fossils are small crystals of calcareous spar, formed
in groups of acute three-sided pyramids; sometimes white and
opaque; at other times~yellowish or hair brown and translucent,
lining cavities of buff marly limestone; from the cliffs near South
Shields and Marsden.
Botryoidal masses of fetid limestone devoid of magnesia, in balls
varying from the size of a pea to two feet in diameter, imbedded in
soft, marly, magnesian limestone, are found at Hartlepool, in the
quarry at Building hill, near Sunderland, and on the sea-coast a mile
or two north of Monk Wearmouth. These balls are radiated from
the center, their colour hair brown, fracture shining, cross fracture
splendent approaching to vitreous: white calcareous spar is frequently
observed within them. See Sowerby, Brit. Min. tab. 38.
Stalactitical fetid limestone. See Sowerby, tab. 148. These
cellular masses resemble corallines, and are also met with in the
marly limestone above described,
Organic remains are rarely met with in this limestone. The most
remarkable one was found in a quarry at Low Pallion. It is the im-
pression of a fish,* which appears to belong to the genus Chetodon.
* See Plate 2.
Vou, Iv. B
10 Mr. N. J. Wincw oz the Geology of
In length it is about 81 inches, and 45 in breadth. The dorsal fin
reaches from the middle of the back to the tail. |
From Humbleton quarry, situated a mile from Bishop Wearmouth,
on the road to Durham, I have received the following specimens,
imbedded in hard buff-coloured crystalline limestone.
1, Casts of the internal part of the vertebral column of the Cap
Encrinite. See Parkinson, vol. 2. tab. 10. fig. 4.
2. A species of Donax with hair-like spines.
S. Casts of reticulated Alcyonite. Parkinson, vol. 2. tab. 10,
fig, 1, 2, 3.
4, Smooth shelled bivalves, from the size of a pea to that of a
cockle, resembling those of the genus Donax.
5. Small round bodies, delineated by Parkinson, vol. 2. tab. 8.
fig. 10. gi
6. Casts of bivalves, resembling muscles.
7. Casts of Arce and Anomiz. Sowerby, Brit. Min. tab. 55.
8. Impressions of a reticulated marine production resembling
the genus Flustra.
Ill. Coal Measures.
The coal-seams and the rocky strata which together constitute the
coal-formation of Newcastle and Sunderland, are in part covered by
the magnesian limestone, and rest upon the lead-mine measures.
They occupy a hollow, or trough, of which the extreme length from
the Aklington colliery, near the Coquet, in the north, to Cockfield,
in the neighbourhood of West-Auckland, is 58 miles; and the
breadth, from Bywill on the Tyne, to the sea-shore, is 24 miles.
This formation first makes its appearance on the south bank. of the
Northumberland and Durham. il
Coquet, near that river’s junction with the sea, and bounds the coast
of Northumberland in a south-south-eastern direction for 23 miles.
It then crosses the mouth of the Tyne; after which the magnesian
limestone begins to cover a part of it, and continues to intrude more
and more upon it until both approach the Tees. The distance from
South Shields to Cockfield is 32 miles in a south-westerly direction.
The western side of this district cannot be so easily defined, since
many of the lead-mine measures strongly resemble those of the coal-
field; but when the Mill-stone grit (a coarse-grained sandstone so
called) and the Blue Encrinal limestone, are seen cropping out, one
may then be sure that the boundary of the coal formation is passed.
However, if a line be drawn from the vicinity of Aklington on the
Coquet, to cross the Tyne at Bywill, the Derwent near Allansford,
and the Wear below Wolsingham, and to terminate at Cockfield, a
tolerably correct idea may be formed of its western limits.
This district is characterized by low round-topped hills, which rise
gently from the sea, and increase in height towards the west. Pontop
pike, situated on the Derwent, not far from the western boundary of
the coal-field, is reckoned by Mr. Fenwick of Dipton, to be very near
1000 feet high, and a pit sunk near the summit proves that it cannot
be much less, That part of Newcastle Leases which lies close to
Spring Gardens, and the western turnpike gate, is ascertained to be
190 feet above the level of the Tyne, and 205 above the sea. Ben-
well hills to the west, and Gateshead Fell to the south, are some-
what higher.
The inequality of the surface does not affect the dip or inclination
of the coal measures; and when they are interrupted or cut off by
the intervention of a valley, they will be found on the sides of the
opposite hills at the same levels, as if the beds had been continuous.
Thus the Grindstone bed may be seen on Byker hill, Gateshead
B2
12 Mr. N. J. Wincn on the Geology of
Fell, and Whickham Banks, though no where in the vales of the
Tyne and the Team, which severally intersect those elevated por-
tions of land. The conclusion is obvious, that the present irregu-
larity of hill and dale has been occasioned by the partial destruction
and dispersion of the uppermost rocky masses, which constitute the
coal formation.
That part of the trough in which the greatest thickness of the
coal measures is found, seems to lie in the vicinity of Jarrow; and
from this point the beds appear to rise to some considerable distance
on each side, particularly in a western direction. The average dip of
the coal measures is 1 inch in 20; but this inclination is by no means
uniform in every part of the district. Thus that seam of coal called
the High Main which lies buried at Jarrow, under 160 fathoms of
beds of stone, soon rises to the clay in a north-easterly direction, and
bassets out in the cliffs between Cullercoats and Tynemouth. In its
north-westerly range it reaches Benwell hills, and at Pontop nearly 18
miles due west of the sea shore at Sunderland it is met with at 3814
fathoms from the surface. In a southerly direction it is found at
52 fathoms on Gateshead Fell, but bassets out before it reaches the
Wear. |
The principal substances besides coal, which constitute the Coal
formation, are shale and sandstone ; which as they vary in hardness
or colour receive different provincial names from the miners. It is
not possible to discover in the Coal measures any regular order of
succession, which will apply to the whole Coalfield, and it is even
with difficulty that in very limited portions of it the continuity of
particular seams can be traced. This arises from the variable thick-
ness and the rapid enlargement and contraction of the different
beds; that which in one section is scarcely perceptible, having at-
tained in a neighbouring pit the thickness of several fathoms. It is
Northumberland and Durham. 13
thus that the Five Quarter coal seam of the mines on the Wear is
divided into the Metal and Stone-Coal seams of Sheriff Hill, and
that the Low-main seam of the Wear becomes the Five Quarter and
Six Quarter seams of the Tyne and Gateshead Fell. Thus also in
Brandling and Hebburn collieries a parting of stone first divides
and afterwards usurps the place of the High Main coal seam ; and
thus the two upper coal seams that are well worth working (see
the section of Montague colliery north) at Kenton, are no longer
so in the neighbouring colliery of Killingworth. ‘The following is
an account of a similar occurrence in Montague colliery, abridged
from an unpublished Memoir, by Mr. Thomas, of Denton, on the
dykes found in that mine. Within the Newbiggin Stone-Coal
seam, at 20 inches from the floor, there is a band of a soft clayey
substance 13 inch thick: but the band encreasing in thickness to-
wards the east, the coal is divided into two distinct seams, whose
ageregate thickness is less than that of the original seam. At the
distance of 1000 yards to the east, and 300 yards north of the
main dyke,* the band is 24 feet thick ; the upper coal seam 6 inches ;
the lower 16 inches. The band decreases towards the north at
the rate of something more than 1 inch per yard ; and the coal at
the same time increasing, the upper and lower parts are so nearly
united at the distance of 160 yards, as to form again a workable
seam. The upper coal then measures 21 inches, the lower 24,
and the band 15.
It is useless therefore to attempt any general section of the Coal
formation ; and it will be seen in the sections subjoined to this
paper, how difficult it is from want of uniformity in the beds to
identify the coal seams in the vicinity of Newcastle. I refer to the
* The Ninety-fathom Dyke described hereafter.
14 Mr. N. J. Wincu on the Geology of
sections of Hebburn and of Sheriff hill, as exhibiting when taken in
succession, a series of Coal measures of the thickness of about 270
fathoms. In the former colliery are the beds which lie above the
High Main coal; in the latter principally those which lie beneath
it ; together they present the entire order of the coal seams, that are
best understood in the Newcastle district: but it will be seen even
in these two examples, what want of agreement there is in the beds
which lie in the two sections above the High Main coal.
The most valuable seam in the whole Coalfield in point of thick-
ness and quality is that called the High Main, of the mines situated
between Newcastle and Shields. It there averages above 6 feet from
the roof to the floor, contains a large proportion of bitumen, and
is sufficiently hard to bear carriage without breaking into very small
fragments. From this the owners of Old Byker, Byker St. Anthony’s,
Walker, Walker Hill, Willington, Old Benton, and Flatworth mines,
formerly drew their riches; and it continues to supply the present
proprietors of Hartley, Blyth, and Cowpen, north of the 90 fathom
Dyke; of Heaton, Bigge’s Main, Wall’s End, Pevey Main, Colling-
wood Main, and Murton Collieries on the north side of the Tyne,
and of Hebburn, Jarrow, and Manor’s Wall’s End, on the south
side of that river. I have already described in part the basseting
of this coal seam along the course of an eval line, of which Jarrow
is the centre; from which some idea may be formed of the extent
of country which it underlies north of the 90 fathom Dyke. At
a land-sale pit, a little above the Ouse burn Bridge, near Newcastle,
this seam was found at 14 fathoms; but on the Town-moor, from
the numerous vestiges of ancient pits, it appears to be exhausted.
The lower seams under the same lands are without doubt un-
touched. Wallis, in the history of Northumberland, gives an
account of a fire happening in the High Main coal, about 140 years
f.
Northumberland and Durham. 15
ago, on the Town-moor and Fenham estates, which continued to
burn for 30 years. It began at Benwell about a quarter of a mile
north of the Tyne, and at last extended itself northward into the
grounds of Fenham, nearly a mile from where it first appeared.
There were eruptions at Fenham in nearly 20 places; sulphur and
sal-ammoniac being sublimed from the apertures ; but no stones of
magnitude ejected.* Red ashes and burnt clay, the relics of this
pseudo-volcano, are still to be seen on the western declivity of |
Benwell hill, and it is credibly reported that the soil in some parts of
the Fenham estate, has been rendered unproductive by the action of
the fire.
At Byker St. Anthony’s, and at an adjoining ¢olliery, the Low
Main coal is found at 59 fathoms below the High Main; but
though the seam proved to be 63 feet thick, the workings of it were
abandoned as unprofitable ; the coal being extremely fragile, and the
mines very subject to the fire damp. On the south side of the
Tyne, at Felling, Tyne Main, and Gateshead Fell, the quality of
this coal is very much improved, and under the name of the Hutton
Main, it forms one of the most valuable seams on the Wear.
I must refer to the series of sections for a more complete view of
the other coal seams.
I now proceed to give a more particular account of the sub-
stances that form the coal measures.
Of the coal itself three varieties are found ; the common or Slate
coal, Cannel coal, here called Splut, or Parrot coal, and Coarse
coal, also called Splint.
The texture of fine splint is compact, the cross fracture con-
choidal, and the fragments are cubical. Coarse coal is slaty in its
* See a paper by Dr. Lucas Hodgson, on the Salt sublimed, in the Phil. Trans. No. 130.
&
16 Mr. N. J. Wincu on the Geology of
texture, and it seems to be intermediate between common and
cannel coal.
These varieties are not found to occupy separate and peculiar
seams of the coal formation, but alternate irregularly with one
another, as layers of the same bed.
At Wylam they are met with in the following order.
Feet { In.
At 6 fathoms ....|High main
ON, Aver Five quarter..... ae
Splint coal is also found at Throckley, Kenton, and some of the
Lambton collieries situated on the Wear. Coarse coal occurs at
Cockfield and many other places. These two varieties, containing
little bitumen and less sulphur, are used in iron founderies, pot-
teries, &c.; and splint serves as a material for building cottages
and outhouses in the neighbourhood of Throckley Fell.
Potters’ clay is found immediately below the vegetable soil. Its
colour is blueish or smoke grey, and sometimes yellow approaching
to orange, in consequence of a mixture of iron ochre. It is used in
the manufacture of coarse earthenware, bricks, and tiles.
2A
Northumberland and Durham. 17
Shale or slate-clay is found throughout the Coal field, possessing
various shades of colour and degrees of induration. Hard black
and dark grey shale is called Black metal by the miners; it is used
by the manufacturers of potters’ saggers and fire-bricks, but for the
latter purpose Thi/-whin, or hard bituminous shale forming the
floor of the coal seams, is preferred.* Shale of a blueish grey
colour is called Blue metal. A blue bituminous shale, lying imme-
diately below the coal, is called Blue-thil, .
Hard blue metal is one of the most common measures in the
coal-field ; it is a mixture of shale and sandstone, sometimes con-
taining scales of mica; is much harder than Blue metal, and from
its waved structure breaks into sharp wedge-shaped fragments. Its
colour varies from ash-grey to iron-grey.
Clay-stone (of Jameson) is not very common; it varies in colour
from black to ash-grey, and is the Black-stone or Blue-stone of the
miners, (vide St. Anthony’s section,) it is fine-grained in texture,
and breaks into angular fragments.
The following are the principal varieties of sandstone that occur.
White flagstone plate: a greyish-white argillaceous sandstone,
hard and breaking into sharp wedge-shaped fragments. It is quar-
ried for flag-stone at Heworth and on Gateshead Fell, where it is
about two fathoms thick.
Grindstone. sill or post: a light yellowish or buff-coloured fine-
grained sandstone, loosely aggregated, and therefore not very hard.
It crops out on Byker Hill, Whickham Banks, and Gateshead Fell,
where it is about 11 fathoms thick. It is quarried for the well
known Newcastle grindstones, and from its softer parts filtering
stones are made. In many places the upper part of this bed is
* Stourbridge clay is imported for the glass-house pots.
VOL. IV. c
18 Mr. N. J. Wincu on the Geology of
abundantly impregnated with yellow ochre, which is sold under
the name of die-sand.
Fire-stone resembles the grindstone in colour and fracture, but is
soft when first worked. The best is quarried at Burradon near
‘Killingworth: glass-house furnaces are constructed with it.
White post is a fine-grained sandstone, tolerably hard.
White post with whin consists of alternate laminz of soft and
hard sandstone.
Grey post is a fine grained sandstone, containing a large admixture
of clay and sometimes of mica.
Brown post is a slaty micaceous sandstone.
Brown post with Coal pipes is a laminated sandstone traversed by
strings of black shale and coal,
Brown post with skamy partings is a light brown sandstone with
dark brown lamine.
Grey whin or Brown whin is a very hard dirty-brown quartzose
sandstone, sometimes specked with minute white dots, and at other
times containing very small scales of mica: it strongly resembles
granular quartz. A bed of this rock may be seen contiguous to
the basaltic dyke in Walbottle Dean.
What is called by the miners Band in coal is commonly com-
posed of bituminous shale, clay and iron pyrites; sometimes of
sandstone. Girdle means a thin plate: thus Post girdles are layers
of sandstone; Whin girdles in post are layers of hard quartzose
sandstone in softer sandstone ; and Whin girdles in shale are thin
beds of argillaceous iron ore in shale.
The minerals that accompany the coal measures are,
Clay ironstone, forming either thin beds or nodules (catheads )
in the shale.
Northumberland and Durham. 19
Galena is found together with pyrites in the nodules of clay-iron-
stone, that are imbedded in the shale; as at Montagu main, at the
depth of 40 fathoms,
Iron pyrites is found in great adaiunien crystallized and dis-
seminated in the beds both of coal and of shale; it is sold to the
manufacturers of green vitriol,
Azure iron ore is not uncommon in the potters’ clay at Elswick,
and in other brick fields,
Calcareous spar is common, either blended with the coal or in
the form of stalagmites.
The Organic remains found in the coal measures are,
Impressions of plants resembling those of the genera fontinalis
and equisetum, except that the latter are destitute of the jointed
stem of the true equiseta. In shale,
A fern, like polypodium filix mas, (Parkinson, vol. i. tab. 4.
fig. 7.) Impressions of plants, (vide Parkinson, vol. i. tab. 3, fig.
6, 7.) In shale.
A fern, like blechnum boreale, (Parkinson, tab. 4. fig. 1, 2. and
Sowerby, tab. 296.) and another like osmunda regalis ; from Kenton
colliery, and from the shale contiguous to the Coley hill dyke.
In nodules of clay iron-stone.
Impressions of cones, (Parkinson, vol. i, tab. 9. fig. 1.) from
Urpeth Dean, Durham. In nodules of clay ironstone.
Obscure impressions of a fern, from Murton colliery. In nodules
of clay ironstone.
Large flattened lumps of iron pyrites, bearing the form of the
stem and the impression of the bark of a plant resembling an
euphorbia; called by the miners fetrified salmon. From the floor
of several collieries,
c2
20 Mr. N. J. Wincu on the Geology of
Impressions of the bark of a plant resembling a cactus or euphor-
bia, (Sowerby, tab. 49.) from Murton Main colliery; and (Parkinson,
vol. i. tab. 1. fig. G.) from Benwell colliery. In coal.
Vegetable impressions (vide Parkinson, vol. i. tab. 3. fig. 1.) from
Gateshead Fell. In sandstone. .
Cast of a cane-like vegetable, (Parkinson, vol. i. tab. 3. fig. 3.)
from near Coley hill dyke; and (Parkinson, vol. i. tab. 5. fig. 8.)
from Muston colliery.
An aggregate of black quartz crystals diverging from centres ;
having the interstices filled with yellow ochre. It is a mineralized
tree, and it found at Bigge’s main colliery, and often in large masses
on the sea beach. :
Bivalve shells * resembling those of the freshwater muscle, in
dark-grey ironstone, from Wylam and Muston collieries.
Bivalve shells resembling the preceding but much less in size, in
a stratum of black shale and ironstone ; from the rocks in the Tyne
at Low Lights, and from Heaton Dean, near Busy cottage.
Bivalve shells like the last, about half the size of freshwater muscle
shells, in black shale, from Hebburn colliery, at the depth of 130
fathoms. ‘These shells are generally less common in the shale than
in the ironstone that accompanies it.
I have only to remark on the preceding catalogue that it contains
no marine genera; and I do not believe that any marine shells,
zoophytes, or corallines have ever been detected in the coal mea-
sures of this district. ~
* Very similar shells are found in the Clackmannanshire coal-field at North Alloa, in
that of Staffordshire at 'Tividale, and ‘in the great coal-field of Derbyshire and Yorkshire,
where the bed of ironstone that contains them is called the Muscle band. [Communicated
by Mr. Warburton. ]
Northumberland and Durham. 21
The dykes of basalt or greenstone, that intersect the coal mea-
sures, are among the most remarkable occurrences in the Coalfield.
The most considerable basaltic dyke in the immediate neigh-
bourhood of Newcastle is that which passes through Coley hill,
about 4 miles west of the town. A long range of quarries has
here been opened upon it, in some places to the depth of 50 feet,
and laying bare the entire width of the dyke, which is 24 feet.
The dyke in this place appears to have no hade. The basalt of
which it is composed is found in detached masses coated with
yellow ochre. The removal of these brings to view thin layers
of indurated clay with which the fissure is lined, and which break-
ing into small quadrangular prisms is used by the country people
for whetstones: in this substance clay ironstone impressed with
the figures of ferns is very abundant. The upper seam of coal is
here found at about 35 feet from the surface, and where in con-
tact with the dyke is completely charred, forming an ash-grey
porous mass, which breaks into small columnar concretions, ex-
actly resembling the coak obtained by baking coal in close iron
cylinders in the process of distilling coal-tar. Calcareous spar and
sulphur are disseminated through the pores of this substance.
The basalt itself when broken is of a greenish-black colour, and
of a coarse grained fracture. It contains quartz, calcareous spar,
and another mineral, possessing the following characters. The
colour is wax-yellow passing into olive-green; the lustre vitreous,
resembling that of glassy felspar; the fracture foliated. It resists
the action of the blow-pipe without borax, but with it melts into
a white glass. The latter circumstance, and the foliated fracture
distinguish this substance from olivine, which gives a dark green
bead with borax, and presents a fracture more or less conchoidal.
Passing to the east-south-east of the Coley hill dyke in the line
22 Mr. N. J. Wincu on the Geology of
of its direction a vein is found traversing Walker colliery, and_
crossing the Tyne at Walker near Mr. Reay’s house, In the latter
colliery it has been observed and described by Mr. George Hill, to
whose accuracy I owe the plan given in Plate 3, and the following
particulars.
The dyke is well defined, and the Plate represents its horizontal
section taken at the level of the high main coal ]00 fathoms from
the surface. It occasions no alteration in the level of the coal-
measures, and the depth to which it intersects them is unknown,
The dyke has been cut through by horizontal drifts in four places,
from which the following sections have been taken,
Sections at A. A. the two western drifts.
Lieako Nige2.294 a Ls . Gov & arth wetiwe o4
2. Hard greenish rRrratanes firm and ainbeaicon ye 3—-—
3. A fissure filled with nodules of whinstone and sa dnedted
inacement ofblue slate ..... 2 —— g
4. Loose fragments of whinstone and post EE: in tals slate
but commonly less GeRAmGed. 6 fee ve. he Bye, 3
5. Hard greenish whinstone Sinn to Nols. 2802 OUT? Ge ae
6.iGeak: 22 oc'thal ia) «0 spicleea og oihlideb! Peewee Bi bell 1G
Yards 22 1 6
Sections at B. B. the two eastern drifts.
Led
. Coak very hard ase yas te Oey its oe es 6 w, 1 —
2. A confused mixture of nodules of Laiiene ‘ilinetone pyrites
and calcareous spar (the sandstone predominating) cemented
together by pieces of blue and black slate. Water was found, > 6 — —
and there was a plentiful discharge of inflammable gas, while
the drift was being made. . . a of
3. Compact post, with pieces of black sheet eet slate occurring
dt-intervals: 257, 4398 Be eT OTP) ASN ia oe 3 BrTTIVG.
4, Hard greenish whinstone,» i) sé, 2/6 Sayih euecpeelie) oad ee
@.;CGoak like that of No. lL... 4's eo ee & el ee eee
Northumberland and Durham. 23
Further to the south-east and in the line of the direction of the
Walker dyke, a ‘small quarry of basalt was formerly worked about
1 mile north of Boldon hills. The rock was fine grained, nearly
black, and filled with small globules of milk white chalcedony, not
bigger than a mustard seed.
With regard to the basaltic rocks of Coley hill, Walker, and
Boldon, it is by no means well ascertained that they are portions
of the same dyke, connected together below the surface; since no
trace of that of Coley hill could be discovered in the very extensive
and ancient collieries of Montagu and Kenton, situated in its
course at a short distance to the east of it; nor was the Walker
dyke found in any other colliery.
At Walbottle Dean, 55 miles west of Newcastle, below the bridge
on the western road, a double vein of basalt* crosses the ravine in
a diagonal direction, passing nearly due east and west. It hades
to the north at an angle of 78°, and cuts the coal-measures without
altering their dip. On the eastern bank of the ravine it is laid
bare from the level of the brook to the height of about 60 feet.
The northern and southern basaltic portions of the vein, the one 5
the other 6 feet in thickness, are there 13 feet apart, and are sepa-
rated from one another by a confused heap of fragments of sand-
stone and shale broken from the coal-measures. With these frag-
ments are found balls of basaltic tufa parting into concentric layers,
and of a light yellowish brown colour: the balls are most abundant
on the sides of the rubble near to the basalt.
Where the dyke reaches the surface a quarry of the basalt was
formerly worked, which has lately been cleared. A small seam of
coal meets the basalt at no great depth from the quarry-head, but
* Plate 4, fig. 2.
24 Mr. N. J. Wincu on the Geology of
the place of contact is at present inaccessible. In the neighbouring
colliery both portions of the vein hold their course through the
seam there worked, and the coal is charred by their influence.
Some of the blocks from the quarry are quite black, and of an
earthy fracture, and contain nodules of quartz and chalcedony,
varying in magnitude from the size of a pin’s head to that of a
large pea. Other specimens of the rock are hard, coarse grained,
and of an iron-grey colour; but in neither varieties have I found
the mineral resembling adularia, so abundant in the basalt of Coley
hill.
A basaltic dyke 6 feet wide may be seen among the rocks of
the ccal formation at the south-eastern corner of the promontory
on which Tynemouth castle stands. Another, about 3 yards wide,
appears in the cliffs near Seaton sluice ; its direction is west-north-
west, and it may again be seen in Hartley burn. A small whin
dyke was formerly quarried near Bedlington; and another is found
in Cowpen colliery, which has charred the coal in contact with it.
Passing to the south of Newcastle about 2 miles beyond Durham,
a basaltic vein may be seen, when the water is low, at Butterby in
the bed of the Wear. This vein is remarkable for a salt spring
that issues from its interstices, and for a string of galena (first
noticed by Mr. Fenwick of Dipton) that fills a crevice beside it.
Two miles further to the south near the junction of the Auckland
and Darlington roads, is another dyke, the direction of which is
nearly east and west, and on which two quarries are worked, each
about 10 feet wide.
Of the Cockfield dyke a section and description have been given
in the History of Durham, by the late Mr. Dixon, from which
work I derive the following particulars.
This dyke passes in a north-west and south-east direction from
Northumberland and Durham. 25
Cockfield to Botain, situated on the western boundary of the mag-
nesian limestone. Its width is 17 feet at the former place, where
it hades to the south, and throws up the coal-measures on that side
3 fathoms. The low main coal contiguous to the basalt is only 9
inches thick, but enlarges to 6 feet at the distance of 50 yards from
it. The coal is reduced to a cinder, and the sulphur is sublimed
from the pyrites near to the dyke.
I have never been able to trace any of these basaltic veins into
the magnesian limestone, and am almost certain that together with
the other members of the coal formation, they are covered by it.
Continuing the line of direction of the Cockfield dyke from
Botain to the south-east, after passing the eastern boundary of the
magnesian limestone, we meet with a dyke on the banks of the
Tees a little below Yarm. It there cuts the red sandstone, and
continuing its course in the same direction is well known to tra-
verse the north-eastern part of Yorkshire.
Besides the fissures filled with basalt, others of a very different
nature intersect the Coal-field. These if large are also called dykes,
but, if inconsiderable, troubles, slips or bitches; and are the same
that some geologists have called faults.
I have already noticed the main or ninety-fathom-dyke, when
speaking of the limestone quarry at Whitley, where it is seen
dividing the coal-measures in the cliff, and passing into the sea.
It receives its name from the degree of throw which generally
attends it in the strata through which it passes, and which are
cast down on the northern side about 90 fathoms. At Whitley the
same bed of coal which is found at 7 fathoms on the southern side
of it, is found at 50 on the northern, the measures being there
thrown up on the southern side 43 fathoms. From this point the
dyke ranges, though not in a straight line, through that part of
VoL. Iv. D
26 Mr. N..J. Wincu on the Geology of
the country formerly called Killingworth moor, and. passing: near
Gosforth church, Denton hall, and by the north corner of the
field east of W. Denton’s house, crosses the Tyne in the direction
of Reyton church, and proceeds to the south-west by Greenside
and Lead-gate. Farther it has not been traced; but it is highly
probable that it traverses the lead mine district; and produces
lateral and valuable metalliferous veins therein.
It will appear from the two subjoined sections of Montagu
Colliery, taken from opposite sides of this fissure, that 11 seams of
coal (two of which are worth working) together with their accom-
panying strata which are found on the northern side, have dis-
appeared on the southern. The exact throw in the measures
occasioned by the dyke cannot be ascertained from these sec-
tions, one of them being that of a pit near to Scott’s wood close
to the Tyne, the other belonging to a shaft sunk in much higher
ground 13 mile north of the former.
_* The hade of the dyke in this colliery is imperceptible: the
space between the cheeks measures about 22 yards, and is filled
with soft and hard sandstone. A perpendicular fissure, the sides of
which are quite smooth, divides the stony contents of the dyke into
two equal parts, and when perforated was found to be filled with
soft clay and water. On the south side the coal-measures preserve
their usual dip of 5° until close to the dyke: on the northern from
the distance of 150 yards they rise to the dyke at an angle of 20°,
but at the distance of 600 yards they regain their accustomed
position. In some parts the coal is deteriorated in quality to the
* I have extracted these particulars from a memoir on the Montagu colliery, by Mr.
Thomas, of Denton, in which are described the dykes and slips met with in the workings
of that mine. I am partly indebted to the same gentleman for the information on thé.
‘direction of the main dyke.
Northumberland and Durham. 27
distance of 20 yards from the dyke ; but in others to that of 3 or 4
yards only.
From the southern side of the main dyke two others branch off,
one to the south-east, the other to the south-west. The latter is
called from its breadth the 70 yard dyke, and is filled with a body
of hard and soft sandstone. This intersects the upper or Beaumont
seam, which is not thrown out of its level by the interruption.
The seam however decreases in thickness from the distance of 15
or 16 yards, and the coal first becomes sooty, and at length assumes
the appearance of coak. This phenomenon is ipkhewn elsewhere
except in the vicinity of basaltic dykes.
The south eastern branch is only 20 yards in breadth, and hard
white sandstone together with other rocky fragments fill the cavity,
and are in part cemented together by calcareous spar. Although
the strata ate thrown up only 20 feet on the north-eastern side of
the vein, yet great confusion has taken place in its vicinity, and
much water was found to issue froin it.
From the northern side of this part of the main dyke many small
slips extend, some of which alter the level of the Newbiggin coal-
seam without affecting that of the Kenton seam lying only 13
fathoms above it.
* The Birtley, Tantoby or Tanfield Brkoct is next in magnitude
and length after the main dyke. From Tatfield on the Wear it
ranges towards the west, passing through Leefield, Ouston, Birtley
Fell, and Urpeth collieries: thence in the direction of Beamish hall
it traverses Tanfield Moor, and crosses the Derwent near Derwent-
coat Forge. In Tanfield Moor colliery it is in all an upcast on the
northern side of 40 fathoms ; but instead of consisting of one strong
* Tam indebted to Mr, Fenwick of Dipton for the information which follows, respect-
ing the other dykes which traverse the Coal-field.
D2
28 Mr. N. J. Wincu on the Geology of
vein, it appears to be divided into a number of small branches,
some of which are upcasts and some downcasts, which break and
rend the coal-measures to the width of 200 yards. In the Wear
water mines it is an upcast on the northern side of 30 fathoms.
The Thistle pit dyke which is a downcast of eight fathoms to
the south, and traverses the Coal-field from west to east, appears
to have been as well known to the miners who lived nearly a cen-
tury since, as to those of the present day. It was the southern
limit of the ancient colliery situated at Heaton and Benton banks,
and by perforating it the mine at Heaton was inundated on the 3d
of May, 1815, when the viewer and seventy-four men and boys
lost their livess—For an account of this catastrophe, see Monthly
Magazine and Philosophical Journal.
The Heworth dyke is an upcast on the southern side of 25
fathoms, and from the vicinity of Falling hall it stretches towards
the west, and enters the main dyke at Ryton. The high-main coal
to the south of this dyke is said to lose a strong parting known by
the name of Heworth band.
At Hebburn, Oxclose, Ravensworth, Lambton, Newbottle, Lum-
ley, Raynton, and every other colliery worked in the district, simi-
lar dykes occur; and, following the same law as the veins of the
Lead-mine district, they elevate the strata on that side towards
which they dip.
Whatever be the throw or difference of level occasioned in the
coal-measures by these dykes, it never happens, as might be expected,
that a precipitous face of rock is left on the elevated side; or that
the lower side is covered by an alluvial deposit, which connects the
inequality of the beds that are in situ ; but the surface of the ground
covering the vein is rendered level by the absolute removal of the
rocky strata on the elevated side. The same phenomena have been
Northumberland and Durham. 29
observed in other parts of the kingdom; and render evident the
operation of a most powerful agent employed in tearing up the
surface, and in dispersing the fragments of the ruin.
In the coal measures near the edges of those dykes rounded
pebbles of sandstone and fragments of coal cemented together by
sand are sometimes met with; as in Lawson main, Sheriff hill, and
Montagu Main collieries.
Galena has been found in a dyke in Willington colliery, and a
small string of the same ore has been observed in the main dyke at
Whitley. A salt spring issues from a slip in Birtley colliery.
‘The dykes are an endless source of difficulty and expense to the
coal owner, throwing the seams out of their levels, and filling the
mines with water and fire damp. At the same time they are not
without their use; when veins are filled, as is often the case, with
stiff clay, numerous springs are damned up and brought to the
surface ; and by means of downcast dykes valuable beds of coal are
preserved, which would otherwise have cropped out and been lost
altogether. Thus the high-main, the five-quarter, and the seven-
quarter coal seams would not now have existed in the country to
the north of the main dyke but for the i depression of the
beds occasioned by that chasm.
The other irregularities observed in the coal measures are the
following :
1. Large wedge-shaped portions of the strata that are occasion-
ally found to have sunk from their level. This occurrence was
noticed in Cockfield colliery by Mr. Dixon, and a section of it is
given in the history of Durham. A much more serious difficulty
of the same kind was surmounted within these few years in
Hebburn colliery by Mr. Buddle.
2. Fissures that divide the strata, but do not alter their level,
30 Mr. N. J. Wincu on the Geology of
and which sometimes do not descend lower than the upper seams
of coal. These are called gashes by Williams, and washes by our
miners: they are filled with water, clay, sand, and rounded sand-
stone sh i similar to those in the beds of rivulets.
. Basin-formed depressions in the floors of the mines, edited
suiellie by the miners; by which the coal is considerably thickened,
the roof of the seam preserving its regularity. These occur when
the coal is nearly horizontal.
4. Nips, where the coal nearly disappears, the floor and the
roof coming into contact. Near Fawlon Slate in the neighbour-
hood of Fenham, 80 acres of coal are said to be lost in this
manner.
At Hetton and at Hebburn, and in other parts of the Coal-field,
the coal-measures are covered by large tracts of quicksand, which
appear to have been the beds of ancient lakes. Mr. Fenwick has
lately penetrated through a most formidable obstruction of this kind
at Hetton by means of a number of cast-iron cylinders.
Having now given a general account of the coal beds, and of
the derangements to which they are subject, I proceed to the
Colliery Sections, with which I commence on the northern side of
the main dyke near the sea, and thence pass towards the west:
then crossing to the southern side of the main dyke at Montagu
colliery and returning to the east, I exhibit the strata pierced at some
of the principal collieries on the Tyne, and the lower beds found
at Gateshead Fell and on the Wear. Some other examples follow,
which are taken from the western and south-western borders of the
Coal-field. |
Northumberland and Durham.
Section of the Strata at Hartley Colliery.
Clay, Sand, &c. to the Coal-
Post : 4
White post A . .
Benton Seam .
Clay °
Grounp Coat .
Thil of ditto 4
Blue Metal
Black ditto
Blue ditto Fs ;
Black ditto . :
Grey ditto with girdles :
Blue ditto . > .
Merat Coat . :
Thil :
Grey Metal with post girdles
White post : .
Whin . . °
White post . °
Blue Metal . .
White post . é
Grey Metal with girdles
White post . .
Grey Metal S
Blue ditto
Mixep Coat and SronE
Black Stone
White post
Grey Metal.
Post girdle .
Grey Metal
Post girdles.
Grey Metal :
Blue ditto -
White post . -
Blue Stone
Yarp Coats.
feel Eri Beebo Ghar ies Ca eee
a ees ed ed ee es err ere er rec eon el reser belied prewar br
Carried forward
Fs.
or
Nj
_
Heacatlatl "|
| Perl setae | “pen | eer on SE"
rT
—
ome | oe
oo
Mr. N. J. Wincu on the Geology of
Strata passed through by Killingworth Sinking Pit.
52
Fs.
Clay : A : : 8
Coa 4 . - —
Grey Metal : 5 —
Grey Post Girdles . : : —
Grey Metal Stone . vie
Strong Post mixed with Whin _—
Post . ‘ 5 phe
Black Stone : ——
Coa 4 - (—
Black Stone . Et =
Coan : a 6 - (—
Grey Metal . : . «> tae
Strong blue Stone 2
Cosre. : : —
Grey Metal . . —
Coa : 5 - _—
Blue Stone . A : conc pl
Whin Girdle . _—
Blue Stone and Whin Giraies —
Coa, . P 5 _—
Gray Thil ° pate |
Grey post ° : . ._—
Blue stone. 5 P ——
Coat —
Grey and ine: Metal with i Girdles 1
Blue Stone —
Coa 3 A “1 _—
Grey Thil . . : oy
Strong grey post . ° je gh
Grey Metal stone —
Slaty Coax, mixed with, Black- (em
stone :
Grey Thil :
Slaty Coan : —
Grey post with water, 2,
Grey Metal with strong Girdles © 1
Strong white post —
Grey ‘Blue Metal with Girdles. 1
Coan . . : =
Blue Metal ° —
Coat —
Grey post with Metal Girdles “ 3
and lumps .
Coan; . ; . -_—
Grey Thil . : : _—
Coa a
Grey and blue Metal with a 3
Girdles .
Coan . —
Thil —
Grey Metal stone with post Girdles 2
Soft blue Metal withlumps , 6
White post , : ’ eoil f
Blue grey Metal, : _=—
Grey post 5 - wa
Carried forward 65
Ft.
0s. UEMOAD, |cto.Ao ml. ex.keter, | Peau | ames [ereries, | am
mR CO aetiorcs |x | Penn son i=.) She etonosel « mrco wahoo aae| ede Feet Coo we | | pags
Lo el ee cence |
In.
1
” This Seam is found in Hebburn and Jarrow Collieries.
+ This seam is generally found on the south side of the Main dyke,
B lies at about 112 fathoms from the surface.
Fs. Ft. In.
Brough fa forward 65 — 1
Black Stone - — 4—
Cosui ye —— 8
Grey Thil and Whin Girdles - 1——
Strong blue stone . F C 1 — —
Black stone 3 . a sy
Coa, . 5 -—-— 8
Grey Thil . -— 4—
White post with Whin Girdles 2 3—
Grey Metal and Girdles oe
Black Stone mixed with Coan. — 5 —
\Soft grey Metal . : — 3—
Grey Metal c . 1 3 —
Coat . c — 1 6
Grey blue Metal — | —
White post 1 2—
Blue Metal . — j-—
Coa — 110
Grey Metal with Post Girdtés | PY eG yams
Coat 4 4 ee Ste ace
Grey Metal fone 5 — 2—
Grey post . . ee
Grey and blue Metal —- 4—
White post — 3—
Grey and blue Metal ‘an ‘Whin it 6
Girdles : , ¢
Black Stone “ 3 d= lee eee
Coat (A) ipl: mae ty lowit
White post 1 — —
Grey Metal with past girdles 5
Whin and white post : oo gee may
Blue Metal with Post Girdles . 2 4 6
Black Metal 3 Sos
Blue Metal and Girdles eee
Black Stone : : -—— Q
Coat —— 9Qg
Grey Thil and Whin Lamps — 4—
Blue Metal — 4—
White post 5 : 3 2 —
Black Metal 5 . —— 6
Coat : 3 ‘ —— 7
Grey Metal . — — 10
Grey post. : 246
Blue Metal . 5 — 4
Black Metal . — 1 8
Grey and white post with as hate
partings -. .
Grey and blue Metal 5 —
Black Metal bs > AG
Coa a s : 1 —
Grey Metal . — 5 7
White post with metal partings. 8) 4556,
Tor Coat, rather coarse —— 4
Crean Coat (B) 1 — if
Borrom Coat to be curved an —— §
Total 115 — 7!
when the Tyne High main Coat
Northumberland and Durham.
33
Boring made at Coxlodge, November 26th, 1761.
Fs.
Soil. : t .
Strong stony clay
Black Metal pb
Brown post
Coat (but will not cake or burn)
Grey Metal
White and grey post aril water
Grey Metal . -
Grey post with water
Strong white post mixed withWhin
Grey Metal stone with post gir-
dles :
Blue and black Metal with Scares
1
of Coal %
Coat : z )—
Brassy lump —
Coa —
Soft blue and hiack Metal —
Grey Metal or post . . -~
Thready Whin which sets away
the water*
Grey post : . ._
Black skamy stone. _—
Grey Metal stone oe!
Soft black and blue Metal —
FoutCoau . -)—
Soft black grey Metal f—
Coat —
Soft black danty+ Metal dead Deez
with Coalees o)35 56 5
Grey Metal . : «toh
Ditto and blue ¢ _—
Harp Coat : _
Black slaty stone :
Coat, but slaty in the middle
;
Carried forward 23
‘Ft.
el Piel me ie se lel 1]
m1] roc |
cs
In.
LE io! wat |
OOo
Fog) Pts tint:
Brought forward 23 4 6
Grey Metal . -—- 2@—
Blue Metal scared withi Coal . —— 3
—||Coat, but brassy at top ~——!11
Coax mixed with black metal i —— 5
Grey Metal. : — 1—
White and grey post - ZS
Blue grey Metal 4 — 2 3
Hard slaty Coat @—— 5
Hard Coan (A). §— 11
Grey Metal — 1 6
Grey skamy post with —_— ne ae
. partings vs
Whin, mixed with strong white? ee
post at bottom . o§
Grey Metal stone with vig gir-t
dles , ¥ wh ee
Blue and black Metal wo
Grey Metal mixed with a ath Gy. 3°"6
Black Metal — |1—
Grey Metal . 2——
Grey and white post ue 2 42 6
Grey Metal . . - — 5 6
Coan -_—-— 7
Grey Metal scared with Coar. —— 4
Grey Metal stone : oy Boje
Soft black and blue Metal ot. SOs G
Coat ° ~—— 8
Foul slaty Coat . ‘ —— $
Grey Metal with girdles @ § 1: 2s—
Strong white post . .- ™—
Coat (B) 5 -— 48
Black Metal scared with Cal. eee g
Left off in Whitish grey post . — 2 4
Total Depth 58 3 $3
N.B. This Section, as also the preceding at Killingworth, is on the north or dip side
of the Main dyke.
Seams of Coal at Walbottle Colliery at the Newburn winning. »
Engine Seam . .
Main Coal . 2 :
Splint Coal . .
; Ft. In. :
at 50 fathoms . . 3 — 8 thick
° ° 3 fem ye eS
69
85
. - 4—O0—
The last Seam consists of 3 feet 4 inches of Clean Coal, and about 8 inches of Splint
next the Thil.
* The Miner’s term to express that the water escapes by,percolation.
j E
Worl tv.
+ Seoty.
34 Mr. N. J. Wincn on the Geology of
Seams of Coal at Throckley Colliery.
Ft. In.
Engine Seam : : at 54 fathoms - - . 3) *S.threk
Main Coal . - . 70 ° - $$ O—
Splint Coal . 86 3 » &¢ §—
Seams of Coal at Wylam Colliery.
High Main : at 6 fathoms . . Stote® titel
Five Quarter Coal. ° 21 : » 3 4b —
Six Quarter Coal ‘ 26 : ~ 8 4—
Yard Coal - a2 4 - .1 2—
Horsley Wood Sate 2 38 5 / — 11—
Seams of Coal at Holywell Main, or Reins by Brunton.
Grey Seam, or san re at OOkathems ; . 4. 6thick
Stone Coal ¢
Five Quarter Coal 3 17 s eS
Six Quarter Coal ; 35 : . 8 O—
Section of the Strata at Montagu Main Colliery, on the North side of
the Ninety Fathom Dyke.
Fath. Yds. Ft. In. Fath. Yds. Ft. In.
Soil and Clay é pet de Brought over 27 — — —
Grey Metal stone . 3 1— —||Grey Metal stone with 2 1
Strong Grey post 2 1 girdles 2 * we i
Grey Metalstone with girdles4 — 1 6|| White post A . oo Sg
Grey post with mirartene err -— 2 6]| Metal stone 4 ook eae
Whin 5 s — — — 9Q/| Blue Grey metal oa Oey
Blue Metal stone . 56 2 2 —Stone'Coar eee oe
1*CoaL (waste of the Black Metal stone J 3 rd "be Se Se E
7 quarter Coal, or 9 Coan ‘ eee — —— J, 9
Kenton Main, worked( = Black Metal stone fe © 6 ae
out in 1690) : Coan x an a oe
Blue Grey metal - —— 1 —||Grey Metal stone -—- 1 1i-—
Grey Metal stone . 2— 2 —+)|Strong White post & ‘te dee dade —
Grey post : » 1 i——i ———
pee Carried forward 37 1 — &
Carried forward 27 — — — :
* Kenton Main in the colliery of Kenton.
Ft. In,
Good (Coaliy.) "322, 46
Ditto and band — 6
GoodCoal. . ..41 2
Northumberland and Durham.
Fath. Yds, Ft.
Brought forward 37
Strong grey Metal stone
Strong white post :
Grey Metal stone :
3 Coar
Grey stone with Post girdles 3
Mixture whin .
Grey post
Grey Metal stone
Coan
Grey Metal stone
Coat
Grey Metal stone
Strong white post
6 Coat
Grey Metal stone
Grey post
Strong white post »
Dark grey metal
Coat °
Grey Metal stone .
Coan .
Grey Metal stone :
Black slaty Metal mixed
with Coat
Strong grey Metal stone 5
Strong white post with whin 12
Grey Metal stone with
black skamy partings
Strong white pest . rg
Coar . .
Grey Metal stone 4
Grey Metal stone with t
\ ;
2
a
os see m &
fio lkel PE abe tied
—_—
girdles
Strong white post ith
Whin girdles and
skamy partings
Coal : 10CoAL
Black slaty metal > Benwell
Coat (foul) Main? *
Grey Metal : -
Strong white post
PE) Tle l | I
Black Greystone .
11 Coa . . °
Blue grey metal . :
12 Coat . . .
Blue grey metal :
Strong white post :
Carried forward 94
* T cannot help thinking the identit
bed those in the north named the Benwell main and Beaumont seam
problematical, and have therefore mar
with a note of interrogation.
Pe
1 ge
— 2
(fats
— 1
— 1
rene
— 1
— 1
— 1
Qo
— |
— 1
— 2
ot
12
qed
— 1
— 2
— 1
— 2
— 1
qou
qos
Gea
Img
—
—_
“JI
ronne! © | teteen
14
17
Fath.
Brought forward 94 1
Grey Metal stone with 1
girdles ay
Grey Metal with skames
of Coal
Grey Metal stone «eee
Grey Metal with a oie
ture of Coal -S
Grey Metal stone Y lathes B
Grey Metal with whin
Grey Metal stone
Coat ; .
Grey Metal ‘
White post : .
Grey Metal
Whin
Strong white post with y nin
partings .
Whin .
Strong white post. _—
Grey Metal stone with ae
girdles and tei {
Coat : °
Grey Metal stone
Strong grey and white post —
Grey Metal stone with
hard girdles $ aii
Strong white post
Whin
Strong white post ‘mixed 1
with whin . . i
Blue Metal . — 1
Mixed Whin girdles or
a i v3
Blue Metal
Coax, Beaumont seam?
Grey Metal stone .
Strong post with whin
Whin . . :
Coat .
Black slate with Coal.
Grey Metal -
Strong white post
Grey skamy post
Strong white at with whin
Coat
Grey Metal stone F
=e
oc ®
EE EI bead
FRE LEA EL bat
rw
| )
Fathoms 118
iow ano. ro 4 | SA
ea anno | |
|
|
a ere e | tm | |
S |
RBAAAONAGD
a vw |
—
_
_
o
of the seams of Coal on the south and north side of the dyke very
E2
36
Mr. N. J. WINCH on the Geology of
Section of the Strata at Montagu Main Colliery, South of the Dyke.
Fath.
Soil” . © . A _
Clay . 2
White post —
Coat —
Black stoné _—
Grey post . ee |
Blue metal stone 2
Grey post 2
Strong white post 2
Grey ] post _—
Strong white post with ‘ 5
black metal partings
Grey post. —
Brown post with Coal pipes —
White post 2
Strong white post w ‘ith Ww he
Comm _
Black stone - 4
Grey metal stone - 4
Brown post with metal
partings t
Coan . . ._—
Grey meta] stone « yoril
Coat —
Black metal ( Benwell
band Main —
Coat —
Grey metal 1
Strong white post 2
. Whin ° - _—
White post : oh Wil
Coat —
Black metal stone. 1
White post 3
Black metal stone 4
Grey metal 5
Grey post with whin girdles 2
Strong white post se 6
Grey metal stone 3
Coat . —
Post girdle . _—
Grey metal stone equal
Coat, Beaumont seam = —
Strong white thil _—
$trong white post fa 2
Coat 7 : _—
Black thil “ 8
Grey metal stone Ae
Grey post . tes
Grey metal stone —
Strong white post - —
"Coszn : —_
Black stone 1
Carried forward 76
Yds, Ft. In.
iat ANS es
ea
— 2 6
ae
1— 2
1 2—
1i—
ie
1 2—
—,1 4
Hv. 8
1 es
hie Fa
—— 6
| aes Aes
2
1 i—
—— 9
tne 10
ee ee
—— 9
1— 6
| ee eee
1 1—
ey Che
BESS Co ee
ee ly
1— 8
lee
— 24
5 (PY es 3 age
ag: ae
eee eyes
—— 8
SRO oe
ee
1— 4
1— 7
—— 4
— 1 6
— 24
— 1 2
5 Oca
— 2 10
1— 4
— 1 8
— 2 4
|
|
|
|
Fath.
Brought forward 76
White post 4 p
Blue metal stone with
post girdles.
Strong white, post with
whin girdles
Black stone
Grey post
1
White post
Grey metal stone with ),
post girdles
White post with whin girdles 3
Grey metal with post girdles—
Coat, Low Low Main
Grey metal stone
White post
Grey metal
Black stone :
Grey metal stone
Grey post
Strong white post with
whin girdles :
Grey metal stone .
Grey post : .
White post ol ge
Grey metal stone
Coa ‘
Grey metal :
Grey metal stone with
post girdles
Coat ¢ °
Grey metal stone
Grey post
Strong white post w vith whin 2
Grey metal stone
Coan
Grey metal stone with
post girdles c
Strong white post with
whin girdles
Blue metal stone —
Strong white post —
Blue metal stone = Ludi
Coa i , 3
Black thil _
Blue metal stone with
5 1
post girdles .
Grey post ° —
Strong white post “eS
Coat, Low Main _
Grey metal stone - 4
4
1
wuts Wale Ga Fe
haya
SPC EeLees: MERE?
. @ . «8
1
2
1
5
he
——
Fathoms 123
Yds. Ft. In.
Ea
— 1 8
—' 1 9
— 1 5
—) ly 2
y ee
— 1 3
ee at
—— 8
1— 4
ee
se
LSPS ay A
— 2i1
4b. aes toe
dy oes
—.1 6
1 3j—
— 210
12@—
pa! Be gala
— bk §$
— — 10
— 2 6
—— 6
Pa tes
— 2 6
ah eee
i ea
oy Se
a) ae
aa eae
— 2 2
—— 5
—— 4
—— 3
1— 4
1
1— 5
— @ §
Northumberland and Durham.
37
The four workable Seams of the preceding Section are, Benwell main, Beaumont seam,
Low main, Low Low main.
Seams of Coal at West Denton or Baker’s main.
Beaumont Seam at 30 fathoms git &
Low Main : AQ 2°10
Low Low Main ‘ 60 Qu}
Strata sunk through in the
F Pit Wall’s-end Colliery.
Fs. Ft.” In, Fs. Ft. In.
Strong clay with tumblers 8 4 — Brought forward 64 3 4
Brown post ° ° ee OTS Chit - - _ — 2—
Soft Metal stone ° . 4 — —}}Grey Metal stone : | ar
White post : . — 1 —} Grey post - bo Ey ES,
Metal stone . 5 — —]| Black stone . : —— 3°38
Grey post . 2 1 —} Coat . . : -—— 4
Metal stone A ; of ee a : : . — 'F' 6
Whin : : . —— 8]| Grey Metal stone 2 == ONG
White post : - 9 1 6] Grey post 5 : errr 5
Ditto and grey post . - 5 — —|} White post - : o einen 4ung
Black stone ° : - — 4 —|| Black stone : : - — 1 8
Coa : : . - —— 8} Coar ° ° ; ._—— 11
Thil . . . . — 2 —} Thil . : -_ — 2—
Grey post. ° . - — 4 6|| Grey Metal stone : peOrg poe
White post . : . - — 1 6]/ Coat (A) ° : -_—— 8
Whin 4 A : - — 1 8] Grey Metal stone : - 2— 9
Grey post . . . 1 1 —Grey post : . -(€2— 9
Blue Metal stone : — 3 6]}| White post C 5 HLTA A'S
Grey post : 3 « 2%— 6]] Blue stone : : i 6
Blue Metal stone - - 2— §8]]Grey post : : al las oe
Grey post . . - 1 — —|] Black stone : ie elds Mees
Whin 3 5 A - — 2 4] Grey post 3 M EP ROTG
White post . . - 2 3 2] Blue Metal stone . — 1 8
Black stone - we - — 2 —|| Black stone ; Sena 4
Coa . : - —— 2]|Grey post - : . 1 3—
Grey Thil : ° +» 2 1 4} Black stone + E : - 3 4—
Grey post eis ale 7 et Bee COAL 3 : ; - — —aheg
Whin 4 ; » — 2 —||Grey Thil A ? ee
White post : . » —— 6] White post . -f( 2——
Whin . c : 5 — 2 3] Whin (very irregular) ; fic At
White post . : 6 5 9{| White post to ee
Coan : : . + —— 8]| Whin (very regular) -|— 4 6
Grey Thil ete al - — I 8] White post : . — we Soe
Grey post. . : : 5 —||Grey post with scares. . [ 3 — —
Blue Metal stone ‘ 2 —]| Grey Metal stone pre Le Ly
Coan ° . : 1 2|| Marn Coat Seam (B) a 1 1—£
Thil . : — 3 —}|| Outset of the Pit : — 3—
CoaL . . . — — 10} - —__—____—_
————— Total 103 2 114
Carried forward 64 3 4 ae ae
* Commonly called the 70 fathom Post. + Black Stone. $ Main Post.
§ In the middle of the Main Coal seam is a band of 24 inches thick. ‘This band lies only in a particular
tract of the mine.
38 Mr. N. J. Wincu on the Geology of
Strata sunk through in Percy Main Engine Pit. 1800.
Northumberland.
Fs. Ft. In. Fs.
Blue Stony clay “ LS — yb Brought forward 67
Sand : » — 2 1] Whin —
Blue Stony clay : - 11 2 11} Grey metal with W hin girdles. 1
Dry ditto - - — 5 6|| Post girdles 1
Leafy ditto — 2 6] Grey “Metal stone —
Sand with a small feeder of w ater — 1 8|| Black metal mixed with Coan _—
Sand and clay 2 — 2 3]|Grey metal F Pe ee
Sinope clay : . — 2 4(|/Skamy white post Se
Gravel : : . — 1 —||Grey metal with girdles _—
Sand with water - - — 1 11} Black stone _—
Leafy clay. : . 3 6|| Grey metal with girdles oT ae
Sand with much water ~ — 4 14 Coar . : Awe
Gravel : . - — 83 10} Thill . ° ) aan
Brown skamy post* 1 2 21||Greyish post ; ite!
Very soft grey metal - — 2 —|| White metal 3 ——
Blue metal : - — 5 —|| White post - MeL a ge
Lightish grey post . - 1 2 —}|Black stone —
Very hard black stone - — 3 6]|Grey metal with girdles —
Soft dark grey metal ~- — 1—|/Coar(A) . : a
White Metal parting - — 1 1}Grey metal . ° ‘ —
Grey Metal girdles » 5 — —]}}Coar Jj
Reddish post with partings . 4 3 —|| Grey metal with girdles dhs!
Lightish grey post - 5 —-—||Grey Metal stone . sor ae
Reddish post with partings . — 1 —|| White post F Bhd (0)
Whitish post » — 3 —|| Black stone . Mes
Soft red metal with partings - — 3 —||Skamy post F A 1
Very course bluish post ony Ae 16) Whin ° 2 =
Brownish Metal mixed with post 1 2 —||Skamy post _—
Blue Metal mixed with post? , 1 Blue stone with birdies esis
girdles : : 4 “|| Dark blue metal sy Phat ©?
Grey ditto ditto ° « 3 — —|]| Black stone ° Fh cis:
Grey Metal stone . « 2 2 10||Coar . _—
Coat — — 6)|Grey Metal stone =
Grey metal > Dark grey metal : 2 —||Grey skamy post _—
Coat — 1 —|| Main post . Pe)
Whin girdle * —-— 6)]/Coazr —
Dark grey metal with girdles - td Se Band Marn Coat (B) 3 =
Dark blue metal . » 1 1 —| Coat —
Grey metal : ~_—- 5— oo
Total Depth 119
Carried forward 67 4 4 ral
* Stone Head.
wo | | meter ia Kouta cee eel rH 20 | h Soismcckooet anges! Beige i ce-0h | eae
1
~
i=}
| | laa! | ow | aoaaw! woe | | > | So | AAWOAWMWAAK:E
v
—_
lot}
NIH
Northumberland and Durham.
Section of the Strata at Howden Pit.
(Bored from the High Main Coal No, 9.)
Blue stone
Grey Metal stone with Whin
girdles . .
Fs. Ft. In.
Outset. P - — 4 8
Surface . - lee
Brown clay - I1-——
Leafy clay 4 »- 1 5—
Bluish gravelly soil - 4— 6
Brown leafy clay »- 1 2—
Sand, gravel and water _—- 3—
Blue gravelly clay — 6——
Sand andgravellyclay,withwater 2 — —
Sand, gravel and water 3 4 6
Alluvial 5 EVE2Ds s WS
Grey metal 5 _- FS
Coa ° . -_—-— 2
Grey metal ° - —— 2
Coa ° . .—-—ll
Thil — 4—
Grey metal with post girdles
and water. Alternate bedsof> 3 2 9
Slate clay and Sandstone
Black stone (Clay stone) . — 4 —
Blue stone with water — 3 6
Grey Thil . — 5 6
Grey Metal stone with water 4 5 6
Skamy grey post withwater 5 2 —
White post with water - 1oO— 4
Grey metal 5 _—- 4—
White post ° bre deg ly
Grey metal , » 1 3—
Black stone : »- 1——
Grey Thil — 5—
Grey metal with Whin girdles 3 1—
Blue metal ° . — 2—
Red metal _ —- 5 —
White post with water »— 7 5—
Red Metal stone — 5—
Grey Metalstonewith Whin girdles —_——
Grey Thil : - — 4 6
Black stone — 1 6
Grey metal with Whin silica io Zien
Blue stone . - — 4—
_3 Coat . “3 = —" 6
Grey metal 4 - — 1 6
4 Coat 4 - — il—
Grey Thil 1— —
Grey metal with post g girdles 5) 3-8
iS
1
—
Carried forward 80 5 6
39
Percy Main Colliery.
Fs. Ft. In.
Brought forward 80 5 6
Blue Metal stone with Whin fp Baas?
girdles °
Grey Metal stone with Whin t 1 we
girdles .
Whin stone — 16
Grey Metal stone with post Lb wirhls fg
girdles ‘ *
Grey metal F - — 2 4
Coat 5 * - — 12
Thil A _—- 3$—
Grey Metal stone with few _' agit
girdles ° °
Grey Metal stone » 13s—
Post and Whin girdles . I 1 —
Grey Metal stone - 14—
Blue stone ‘ - —- 2—
Coat “ ‘ -—- 1.2
Grey Metal stone »- L4—
White post ; é 8 3—
Grey Metal stone _—- 2—
Coan ‘ A .- —-— 10
Grey metal . ~ 1L2—
Blue stone : -_—- 4—
Grey Metal stone ~. 14—
White post ° so 9a I) —
Grey Metal stone with post }_ itt
clyers y
White post with water . 2@—-—
Black stone = _—- 3$—
Blue stone - _—- 2
Grey post . _—- ¢—
Blue stone A -_—- ¢—
Grey Metal stone -_—- 4—
Black stone — 2 6
Post with Grey Metal girdles 1— 2
Dark blue Metal stone . 2 3—
Coab ‘ -—--— 4
Grey Thil < - —- 2—
Grey post ° _—- 2—
Main post - - 10 4—
Coax, High main « Shh a6
Thil, Foul coal,Grey metal,2 __ 5 9
and Coal .
Blue stone with girdles . 3 1 6
Grey metal = - 2——
Grey post - 12—
Grey metal with girdles v Goleta? 9
10 CoaL : ° -_ -- 2—
Fathoms 145 — 6
40 Mr. N. J. Wincu on the Geology of
Strata sunk through in the A Pit, Bigge’s Main Colliery. (Bored from High Main.)
Fs. Ft. In: Fs. Ft. Ine
Clay . 3 . “ie See Brought forward 104 3 —
Brown post with eaten : . 7 — 6||Strong post mixed with Whin . 5 3 —
Coat . - Q ° - —— 8]/\Coar%(5) “ 6 . - —— 9
Blue metal. : - 1 5 —||Blue stone .. * . »- 43—
Strong white post with water 1 3 —jCoar }. 5 : : -(— 1 2
Blue Metal stone - »— S—— (Black stone .. - +» (6)<—— 7
Coat » : J iste 2Gost ho a. : . — 1 8
White post. . 4 — ——||Strong grey post . . 5 3 —
Grey post girdles with water - 3 3 —| Blue stone with post girdles ent 742 O
Soft blue Metal stone 1 — —},Coat .. . - — 2 6
Strong white post mixed with whin 4 3 —|] White post aaa girdles will ——
Soft blue Metal stone. . 5 — —] Ditto with whin and water . 5 3 10
Coat... . . - —— 5] Blue stone .. ‘ - —3—
White post girdles . - 1 3 —} Ditto and Grey girdles - Ls—
Whin ; 3 : - — 8 4] Ditto and Whin girdles el -3 —
Strong white ppt 5 : - 2 1—J|Dittomild .. ~ . Veo -G
Cosi : ‘ - —-— 7]|Coar . : . . -(—— 3
Soft blue Thil x — 5 —|Grey Thi. A -|—— 5
Post mixed with whin and water. 2 3 8|Coan . - . . -|—-— 2
Coat . . ° . - —-— 8] White Thil ; © velo se
Blue stone .. 2 4 AjiCoar . : 6 ». ()K<—— 7
Ditto mixed with scares of Coal. — — 8|Blue Thil . . : -|—— 8
White post mixed with Whin . 1 4 —|/Coan . - : “ -|— 1—
Blue Metal stone é oll g) = WBlue’stone .. ° H -|—— 6
Coans -. — 1 6]/Coar . é j -l-— 1 8
Strong white post with water, i 1 2 —|Strong grey post . of 915? —
Grey post girdles “ -| 1 4 6] Blue stone and Whin girdles -_—- 4—
a Coazr . . t<—— 10]Coar . —— 2
~| Grey Metal stone. -| 2 3 —| Strong white post mixed withwhin — 2 6
(Coat. . -lL—— 8] Whin . sive yp ly 6
Strong white post mixed with whint 5 1 —1] Grey post and. Whin girdles - 2 3—
Grey girdles .. ; .( 3 3—IBlue stone . : o— 2—
Blue and black Metal. § 4 2 4 —]Coar.. (Unknown seam) -— 3 1
Coat os 7 - (— — 5] Grey post with Whin pears - Lo —
Grey Metal stone (1) . . 1 3 —/] Bluestone. : ~ — 5—
Strong white post (2)... oon b=) 51) Coan: ; - -(— 2 6
Ditto with Coal pipes. - 1 3 —}] Blue and grey. meu 1— 6
Ditto with Whin * - 3 — —|Strong post girdles mixed with 3
Ditto with Coal pipes 1 3 —j]) Whin . ° . ‘ =o)
Grey Metal stone with fail ee L),.2)—|/Coan : 5 - (8)< —— 9
Coaxr(3) (High Main) . - 1— 8] Grey Metal stone 4 -| 3— 7
Blue stone with Whin girdles . 4 3 —|/Coar . . . -{—— 2
Strong grey post. : - 1 — —]\ Grey Metal steno F - ~|——) 8
Coan. : 3 : €—12" 6]/Coar . - : -lL-—-— 4
Blue stone : - (4) ; 3 3 —|| Grey post mild : . »_ — 4-4
Coan, +. 5 : : - (— —_ 6||Strong white post : »- 4 2—
| Blue stone : . . _— sg
Carried forward 104 3 — ——
Carried forward 159 1 4
* Called on the river Tyne, below Newcastle bridge, the 70 fathom Coal. On the river Wear it is
ealled the Three quarter Coal. + Supposed to be the Three quarter Coal seam divided. ¢ Called on
the Tyne the 70 fathom Post. § Called on the Tyne the Black stone. (1) Bottom part of Black’stoné.
~(2) The Main Post of the Tyne. (8) High Main Coal of the Tyne.——(4) Metal Coal seam of
the Tyne.——+(5) Stone Coal of the Tyne. (6) Yard Coal of the Tyne, High Main Coal of the Wear.—
(7) Supposed to be the Benshaw Seam, (8) Supposed to be the Six quarter seam divided.
Northumberland and Durham. 41
Fe. Ft. In.! Fs. Ft In.
Brought forward 159 1 4 Brought forward 178 — 2
White post . 4 1 6) Whin ° : < _—- 2—
Coat. (Supposed to be the Five? r Gee Blue stone. ° : — 211
quarter seam . re, el | Black stone . : , — — 10
Be dee ety SS ae. ee), pil Win eesasney ain y
Grey post girdles . . -_— 3— i Blue metal. : , ~Pp— 2 4
Blue stone — 3-—|Coar’, . . . ae — 4
Grey Metal stone with post girdles 2 4—|/Whin . . . — 1—
Whin . . . 3 » — 2 8] Brown post 2— 1
Blue stone. = ‘ - —— 6} Grey Metal stone - 1 5—
White post girdles 3 ff Uli bos | Coat 4 . . : -|\—— 4
Blue stone. * ° . — 4 6] Blue metal . - ° -p— 1 8
White post girdles 1 2 GiiGoar . . : : J— 1—
Blue stone. . — 4 8)Grey metal . . . ae hs Qe
Black stone . 5 - — 5 7| White post : ° - 2——
Grey Metal stone . — 4 —| Ditto girdles 4 2— 1
Mild grey post A aes oe Strong white post mixed with whin ye ad
Coat. (Unknown Seam) - —-— 8]/Grey Metal stone . 5 ay glee nae
Grey Metal stone . _—- 4— —
Mild White post . : - rhs Total Depth 193 — 10
Carried forward 178 — 2
(10) Low Main Coal of the Tyne. Hutton’s seam of the Wear. ;
N.B. All the Seams below the Yarv Coat in this section, lie so irregularly, and are
so disfigured, that it is difficult to recognize them.
Section of the Strata to the Low Main Coal, at St. Anthons Colliery.
Fs, Fr. Ft. In,
In.
Soil and Clay * . 5 — Brought forward 64 ——
Brown post . . - - 12 — —}Grey Metal stone : : —_— —
Coat . - + — — 6]|Strong white post . ——
Blue Metal stone . . 2 5 —||Black Metal stone with hard girdles 2 ——
White girdles : i 2 1 —} Hien Main Coat |) eer
Coa, . : + —-— 8]]/Grey meta! ‘ Ay "Ss —2
White and grey post . - 6 — —]| Post girdles a ee
Soft blue Metal stone - 5 ——j|/Blue metal . ‘ : -— 4
Coax * 4 j 4 - —— 6/! Girdles i § ae ae
White post girdles - 3 — —/j| Blue Metal stone ee
Whin . ees : +d 4. Gipvost~* ¢ ° 5 _— ls
Strong white pee - e . 3 1—t| Blue Metal stone ‘ Se i
Coan. 3 ; « — 1 —} Whin and Blue metal — | 6
Soft blue Thil - 1 5 —/Strong white post . . ob S "Bree
Soft girdles mixed with Whin - 3&3 5 —|| Brown post with water ee may 2
Coat. - — — 6]| Blue Metal stone with grey girdles 22
Blue and Black stone - 38 4—Coar . : . — 3—,
Goar ”. i, : - — — 81 Blue Metal lowe . 2 Se ES
Strong white post - 1 3 —White post . ‘ — 4—
Grey Metal stone : - 1 4—Coar . —— 6
Coan - —— 8]/Strong grey metal with post girdles 2— 6
Grey post mixed with Whin 4 1 —||Strong white post . { ie oe ie
Grey girdles 5 3 . -3 1 —f Whin : — 1—
Blue and Black stone. - 2 2 —}Blue Metal stone . eee f
Coan . F A . - — 1 —]| Grey Metal stone with post girdles 2.4.8
Blue Metal stone with whin girdles 1 4 3
Carried forward 64 — — f
Carried forward 109 3 9
VOL. IV. F
AZ
Fath. Ft. In.
Brought over 109 3 9
Coat : : : —— 6
Blue grey : metal — 3 8
White post. 2— 7
White post mixed with W hin 2—- —
White post. . lebsi2yes
Dark blue Metal and Cos AL. 1. tor Baie
Grey Metal stone and girdles . 2 2 —
White post mixed with Whin . 3— 7
Whin . _— le
White post mixed with Whin.. 1) 6
Goan . 3 — 3 3
Dark grey } Metal stone — 3 6
Carried forward 124 — 6
Mr. N. J. Wincu on the Geology of
Fath. Ft. In.
Brought forward 124 — 6
Grey metal and Whin girdles , 1 4 10
Grey metal and girdles. COL) Bie
White post . . . -_— FS
CoAL, ">. . -_— 8 2
Blue and grey ‘metal : 1 — 4
Coat. = 5 —— 9
Blue and grey metal . - 2——
White post mixed with Whin . — 4 6
Grey metal . ; . “brie
Grey metal and girdles 4 »- 1— 9
Low MainCoar . . - l— 6
Total 135:°°1..6
Strata bored through from the High Main Coal in the Charlotte Pit
Walker Colliery.
Fath.
Sunk from surface to High i 100
Main Coal 5
Box . .
Grey metal with girdles
Coax °
Grey metal. .
Coal with sulphur
Grey metal with girdles
Black stone
Coan D (Stone Coal)
Soft grey metal °
Strong ditto with post girdles
Coat E (YardCoal) :
Grey metal with whin girdles .
Black metal stone with ditto
and sulphur
Strong white post with whin and
metal partings
Grey metal :
Strong white post
Whin 2 . 5 4
Strong white post . . -
Black slate
Coat (Little Coal)
Grey metal stone
White post
Grey metal stone with post girdles
Black stone :
Coat F. (Bensham Seam) 4
foe ity aD
wT
ae feos = tao | El esl
ee ew
eu Heed bed ©
Carried forward 136
Ft. In.
5
5 ee
— 6
LS
2° 8
JO
— 10
— 10
pees
2159
aie
a
rofeelts!
oo
5
Be
— 2
— 8
Se a
Se
At?
— 4
By es
1 4
Fath
Brought forward 136
Grey metal stone with girdles . 2
Coat with water and sulphur .
Grey metal stone with meet girdles 2
Coat
Hard band * J
Coan “t—
Grey metal with post girdles = 2
White post with partings « Bae
Coat —
Blue natal Six Quarter Coal ete
Coa
—
Blue metal with scares F ive
of Coal at top Quar- \—
Coat mixed with black ter
stone Coal J—
Coat clean H. \—
Grey metal : . as
Grey post _
Strong grey post mixed with whin 5
— || Gtey metal with girdles Seeakne!
Strong whin : ° oo
Black slate . . ——
Tender Coax I. —
Brassy Coal with scares of band+ j=
Black slate mixed with Coal . (—
Blue grey metal ° .
Ft.
1
3
ee
a
Cm pws
Fa ee
| ee Oo em ee
[tele]
_
—_
—_
Fathoms 160 3 9
The stratification above the High main Coal, that is from the surface to the High main
Coal in Walker Colliery, is very Similar to the section of the Wall’s-end strata,
* Bandy Coal Seam.
+ Low Main,
Northumberland and Durham.
Strata sunk through in the B. Pit Hebburn Colliery.
Fath. Ft
Clay . A ° 9 5
Grey metal stone . eo 2 |
Post with metal partings »- 8 4
Blue metal ° . - — 2
Coat * . . — 3
Blue metal . OR AS
Grey metal stone ° Peat
Post with metal partings oo ae
Blue metal stone : - — 5
Grey metal with post girdles . 2 4
Blue metal stone supa 2
Grey metal with post girdles 3 ee
Hard white post ee
Grey metal with post girdles - 424
Grey metal with open ie — 3
Blue metal . 6 5
Black and blue metal. . ny E
Coat . . . _——
Black metal : ° ——
White thil . . — A
White post - — 2
Blue metal . . _——
Grey post _—-—
Grey metal mixed with post -— 1
Strong white post . tdi ae
White post with grey metal t aati”
partings ; . .
Strong white post ° - 8—
Coat . . . _——
Grey thil - — 8
Grey metal mixed with thi’ .. 91.5
Grey metal ? -—- 1
Post with metal partings — 3
Strong white post mixed with whin— 3
Grey and blue metal. - — 4
Black stone . . -— 8
Coat ° . . o— —
Black stone . . -_— 1
Coan . . . -— 1
Strong grey thil ‘ _— 2
Strong grey post . hoe
White post girdles with metal sy
partings . . °
White post : . - — 3
# Lille
nie
nie
oa alaxaSanoaall!l!lloalllliii|
Riel
feellllilsoel
_
om
Carried forward 72 3 6
43
Fath. Ft. In.
Brought forward 72 3 6
Thin post girdles with metal _ Hee
partings . . :
Whin t — 3—
White post with metal partings — 5 6
Grey metal . -—- l—
White post ° — 4 9
Blue metal and grey 4 5.9
White post ° . — 4—
Blue and grey metal. ° ge oe
Coat F . —— 5
Blue and grey metal . ne. ee
Coat . . . —— 2
Grey thil ° — 2 4
Blue and grey metal ‘ te:
CoatA.(called the70fathomCoal) — 1 2
Gray thill : : — 4 6
Coau ° pape eee 2
Grey metal and post girdles 2——
Black and rey metal Niel Seam
Post A pyrene! (Nee ep
Coa. ° 5 . -—— 4
Grey thil . 1— —
Blue and grey metal with h post ee
girdles
Strong white post une oO
Brown post with blue metal , 1 110
partings . . .
Strong white post . shell: Dy Taek |
Blue metal < . =
Post 3 ° - — 1 6
Black stone : : _— 5—
White post C : - — 2 6
Blue and grey metal. - 1 5—
Black stone : . - &——
Coat e e ° e Se SS 6
Grey thil . . -_— 4—
Blue and grey metal. ~— 5—
Post ° . 10 2 —
High Main Coat (B) - I1-——
White thil . ° - — 1 8
Slaty Coal ‘ . -— 24
Blue metal . : -_— l—
Total 131 3 114
* This Seam lies all through Hebburn and Jarrow Collieries, and may also be found in Killingworth
section.
E2
44 Mr. N. J. WincH on tthe Geology of
Strata in Gateshead Fell.
Fath. Ft. In. Fath. Ft. In.
Shiver and blue slate . - 8$—— Brought forward 70 4 $
White flag stone . - 2 — —|| Blue stone . : - 2 s—
Grindstone sill ; : -» Ll — —}{ Black stone ; er =
White post . 1 3 —|\ Litre Coat . . _—- 2—
Blue plate : . . 1 — —]|Grey stone . : - 2——
Grey post . - - 1 3—YarpCosar E. . . _ —
Blue plate . ° - 1 — —|{ White post . . 11 3—
White plate . ; . 1 2 —}Bensnam Seam F. — 2—
Blue sill : : ~ 1 — —j Blue plate 3 “ »- 1 3—
White post : : . 8 A —||Banpvy Coat Seam -_— @—
Turee Quarter Coat A. . — 2 3/| White post . ° - 6——
White post : ° -€ 5 3 — Blue plate e : _— 2—
Grey post bene 70 fathom post} 1 — —{/Six Quarrer Coat G. . ~_— 4—-
Dun post . 3 -€ 6 — —||Grey whin, Post plate. - 2 3—
Blue plate (the black stone) . 1 — —/| Five Quarter Seam H. -_ —- 3—
White post (the main post) 11 — —||Grey post . : ~ 1 4a
Uprer Marin Coat B. - 1 — —]| Banpy Coat Seam ° -—- le
Grey post : - 6 — —]{ White post : ° «, 5,1—
Metal plate a — 3 —H Low-marn Coat I. > - 1——
Mera Coat C. - — 3 —|{Thil . _— 2—
White post . : 4 4 —|]| White post . ‘ -;.3 4—
Stone Coat D. . ; — 2 —]| Two Quarter Coat Seam J. — 2 —
Black stone . ~ 1 1 —i White post . 3 op 2s 1. —
Banpy Coar . . » — 1 —]) Harvey’s Matin Coat K. - — 3—
White post . . »— 4 3—
Total 133 Siva
Carried forward 70 4 3 Tw
N. B. The letters in the different sections refer to the respective names of the several
Seams of Coal in the Newcastle district, according to the classification on the river Tyne,
and are as follows, viz.
The Three quarter, or 70 Fathom Coal.
The High-main Coal.
The Metal Coal.
The Stone Coal.
The Yard Coal.
The Bensham Seam.
The Six-Quarter Coal.
The Five-Quarter Coal,
The Low-main Seam.
The Two-Quarter Seam.
Harvey’s Low-main Seam, called also the Beaumont Scam.
RSMO a Op
Northumberland and Durham.
Seams of Coal under Newcastle Town-moor.
High Main
Metal Coal
Stone Coal
Yard Coal
Bensham Coal
Six Quarter Coal
Five Quarter
Low Main Coal.
at
fathoms A és
Seams of Coal at Kellsfield near Gateshead Fell.
High Main
Metal Coal
Stone Coal
Little Coal
Yard Coal
Bensham Coal.
Five Quarter .
Low Main
Harvey’s Seam.
Soil and Clay .
Brown stone .
Grey Metal stone
Brown stone .
White post :
Blue stone ji
Grey post :
Blue slaty stone
Grey stone s
White post ¢
Black slaty stone
Whm < :
Grey post .
White post .
Blue stone .
1 fathoms 5 ;
ee ee ee es
Ft. In.
2 3
1 8
1 10
3 —
5 —
3 —
5 6
3; —_
Section of the Coal Strata on the Wear.
Five Quartir CoaL*
Blue metal .
Grey post .
Grey Metal stone
Whin * ;
White post .
Blue stone :
Carried forward
* Forms the Metal and Stone Coal seams on Sheriff hill.
+ Forms the Six Quarter and Five Quarter seams on Sheriff hill, and on the Tyne.
+ The Low main at Sheriff hill and on the ‘I yne.
60
fol eae) eee | oie ee} eT | delet
Ft.
In.
Bt eye I i ac" ot tA
Brought forward 60
Hieu Main Coat
Blue grey stone
White post .
Grey stone with partings
Brown post’ .
Whin " ;
Maup.in Coat
Blue stone -
White post °
Grey Metal stone
Blue post A
Blue stone .
Low Main Coat
Blue stone .
White post .
Whitt oo. .
Grey post <
Blue metal é
Hurron Seam ¢
eo e+ © © e @
Total
thick
Fs. W..
(fees
7 a
2 i
vis Mal
CaN et
1)
)
iigane |
Ce publ |
a
oo
}
— 1
Tues
yer
— 1
| ees
f (yreeni|
jes
94 1
eagiactieca | bt) tt fot ae
i er ti! a fit ae 2
45
46 Mr. N. J. Wincu on the Geology of
Section of the Strata, at Sheriff Hill on Gateshead Fell.
Fs. Y In. Ps. Yu Et. In.
Shiver and blue slate sillk 3 — — — Brought forward 88 — — —
White flag post 2 — — —} 8 Bensuam Seamt — 1— 3
Grindstone sill e i——— Blue plate Oa a
White post plate - 1 1—-—| 9 Banpy Coat SEAm ——— 9@Q
Blue plate - 1——— White post sill. - 5— 2—
Grey post plate. »- 1 1—— Blue plate bateert: foe ofp ee
Blue plate ‘ 1 — — —||10 Srx Quarzen CoAr a
Whin plate . 1 1—— Grey Whin post . hook: Qe
Blue sill j 1 — — —|/11 Five Quarter Coar§ . — 1— 2
White post sill . 3 1—— Grey post . iy In ars
1 Three quarterCoan . —— 2 3/12 Banny Coax Sram —_—— 9
White post sill . 5 1—— White post |
Grey post 5 » 1 — — — 4/13 Low Main Coat 1 1—— 6
Dun post sill 5 »— 6——— Dark white sill SS) i =
Blue plate 1—— 9 White post . . = en
Eleven fathoms White post 11 — — —|14 Two Quarter Coat SSS
2 Hich Main Coat* . 1 — — — White post sill . 21—— 6
Grey post sill 6 — — — Harvey’s Main eee 1
Metal plate “ 1— — — Wickham Stone Coal. Leesa
3 Merat Coar —— 12 ee
White post 4— 110 Fathoms 134 — — —
4 Stone Coat : -—- Il-—
Black stone sill. - Li-—
5 Banpy Coat SEAM - ——— 6 To the Brockwell, the lowest seam ; which
White post sill . - 4 1— _ 6||crops out at Basty Bank near Conset Park,
Blue plate 4 2 1 — —}} Durham,
Black plate . . —— 1 6
6 Lirrite Coat Seam — — — 6]|Grey metal and Metal stone 5 — 2 10
Grey sill. : v7 o'— ='——|| BROCK WELL SEAM " ; - —- l— 2
7 Yarp Coar . -— i —_ pliicdiy ibe, alll
White post sill . 11 1— — Fathoms 6 — — —
Carried forward 88 — — —
* This Seam does not extend to the mines on the Wear.
+ This and the Metal Coal form the Five Quarter Coal on the Wear.
¢ Maudlin Seam on the Wear.
§ The Six quarter and Five quarter Coal Seams form the Low Main Coal on the Wear.
|| Hutton Seam on the Wear,
Birtley Colliery.*
Fs, Ft. In. Fs. Ft. In.
Brown post . ¢ : -) Brought forward 43 5 6
Grey Metal stone . ‘ White and brown post
Brown stone A A : Grey Metal stone with Whin — 6
White post . 6 . - »32 — —||_ near the bottom . * .
Blue Metal stone . . : Maun. in SEAM : _ — 4 6
Grey post . “ Blue post ° s
Blue and grey Metal stone Blue and grey Metal stone ‘ 12 ae
Five Quarter Coan. ~ — 3 9]| Low Marin Coat : oo Sis
Grey post . Blue Metal stone . . :
Grey Metal stone with wnt 10 2 3|| White post and Whin ‘ i
girdles : . ° : Hurton Seam ° . 4 6
MainCoan . : . -— 5 6
— — Total 76 4 6
Carried forward 43 5 6
* Communicated to the Author by the Rey. W. Turner.
Northumberland and Durham.
Boring at East Rainton Colliery.
Fath. Ft. In Fath. Ft. In,
Sunk to scaffold 10 1 — Brought forward 42 2 6
Box and Bore hole ; . 12 — —||Strong grey stone mixed with whin— 4 —
Whin c — — 10||Grey Metal stone with water . 2— 6
Strong white post : - — 2 —||Strong Greystone mixed withWhin 1 4 —
Grey metal partings and post a Whin -, =) An2
girdles. Grey metal with whin girdles oa
Dark grey metal (the black stone) 4 3 5/||Foun Coat C. P si 1, 8
Gulbetty{ white post with 9 Soft grey metal — 2—
much water 3s ~~ || Strong grey metal with whin girdles 2 4—
White post with water 7 |— $3 6||Stronggrey post with mixture of whin 2 — —
Grey metal stoneand girdles | 3 | 1 1 —||Strong grey metal stone 2 4—
‘White post with water + | 2 4 —|| Black grey metal : - —— 6
Strong white post mixed ag 6| Five Quarter Coat D. - — 3 8
with whin & Strong grey metal . - — 3$—
White post with wae S 2 3 9|| Strong post mixed with whin — 2—
Strong blue metal with z moe od Strong grey metal stone — 5——
girdles and water . s Strong post mixed with whin 1 1—
Soft grey metal ‘ — 2 —||Strong grey metal mixed with whin 1 2 —
Black grey metal with scares of 3 Grey metal : -_—- 1l—
Coal* B. : ‘ —|\Hicu Main Coatt E- - I1——
Strong grey metal with water . 1— 6 oe ae
Total 67 3 —
Carried forward 42 2 6 —
¢ Full of fissures.
* Situation of the Tyne High Main Coal.
The Main Coal B. is seldom in perfection unless the Main
+ Called the Yard Coal on the river Tyne.
post is also solid and good.
Seams of Coal at Axwell Park.
High Main at Windy hill
Stone Coal :
Jet or Splint Coal
Three quarter Coal
Fth. Ft. In.
at 6 fathoms i
30 — 4—
- 41 esl Ove.
« 45 —— —.2.3
The first of these seams is good Coal, but is almost worked out. The second is slaty and
bandy, small and tender, but burns well,
The third is a very bad seam of Coal.
Seams of Coal at Morrisfield.
Three quarter Coal
Coal next the roof
Ft. 1
Band of soft black stone
Scarey bandy Coal
This is a very tender and dull burning Coal.
‘ Fath. Ft. In.
. at 45 fathoms — 2 $3
3
289 pees
a
bss
A hole was bored below it to
of 16 fathoms for the Shildon seam, but it was not found.
the depth
48 Mr. N. J. WincH on the Geology of
Seams of Coal at Thornley or Garesfield Colliery, two miles South
of Axwell.
Ft. In. Fath. Fe. In.
The Stone and Five-quarter Coal seams Stone Coal 3}
Fire clay 27 2 -6 >at 30h ait 2 2a
Five-quarter Coal 3 6)
Brockwell seam : . - . at 39 fath — 3 4
Towards the east the Fire clay between the Stone Coal and Five-quarter Coal becomes
so thick as not to be workable, and the Coal forms two distinct seams. The Coal is ex-
tremely tender and unfit for the London market.
Strata in Landchester Common.
Fath. Ft. In. Fath. Ft. In.
Soil and clay A ye, Brought forward 58 3 —
Brown post a . 1 5 9} Black grey metal stone 58 2 ang
Grey metal stone . . 3 3 —||Grey metal stone with post girdles 3 — 2
Coat : . - — — 10|| Dark grey metal stone with sea } Fae Wh
Grey metal stone - . 2 4—T|| girdles
Coax A, - — 2 —]Brown post . - _ — 3—
Grey metal stone mixed - 8 1 6||Grey metal stone ‘ . — 3 2
Coan x — — §8]|Brown post . a == "Benn
Grey metal stone mixed with Coal — 4 9|jGrey post : : — 3 1
Grey metal stone 3 - 2% — —|| White post ; Hive Ht CQ
Grey post : 1 — 6|| Black metal stone : - — 1 3
Grey metal stone, top thereof pny Strong white post . - S$— 6
mixed with girdles Grey metal stone ° - — 4 6
White post. Shield row post 12 — 10 Strong grey post ° wor eae
(the Main post) pe Whin ° : — 3—
Suretp Row Coar B. 5 3||Strong grey post 2) 1h
Whitish grey metal stone with ; 6 3 Whin — 3 8
post girdles c : ~~ || Grey and white post mixed with a
Grey post . 4 -_ 2 2 St, whin 4 ‘ .
Grey metal stone . - — 3 —|| Blue grey metal stone mixed i? te
White post. - 1 3—j] withwhin girdles . Cs
Grey metal stone . - 3 2— Aes the Hutton’s Seam E. 1 i—
Black-grey metal stone ps! White post’. : -~— 510
Coat, the Harp Coan Sram C. — 4 9 oll Cou F. : . i — 1 8
Dark grey metal stone mixed oye ay Blue metal stone 4 oP Sag
with Coal | Grey post mixed with whin 3 — —
Coat, the Brass Coax Scam D. — 5 3] Blue metal stene “ 1 5—
White post . «+ 1 2 2iCoat, the Low Main F orG a 3 6
Grey metal stone with girdles — 4— at
Total 96 2 2
Carried forward 58
)
|
* It is rather doubtful whether these two Coals are not the same seam divided.
Northumberland and Durham. 49
Strata at Pontop Pike Colliery, situated on Landchester Common.
Fath. Ft. In. Fath, Fr. In.
Soil and clay ° . . 1-—— Brought forward 58 3 —
Brown post ° . + 1 5 9} Black grey metal stone — 1 3
Grey metal stone ‘ - %& 3 —]Grey metal stone with post girdles 3— 2
Coat - 3 + — — 101 Dark grey metal stone with pest § ay =.
Grey metal stone ; » 2 4—!1 girdles 4 , °
Coat A. . . + — 2 —|| Brown post 2 . — 3—
Grey metal stone mixed - 8 1 6)Grey metal stone , . —— & 2
Coan ° . — — 8] Brown post : re ee
Grey metal stone mixed with Coal —-,.4 9] Grey post : . «wie 1
Grey metal stone . 2 — —|| White post : . ol de ee ge
Grey post 1 — 6] Black metal stone ° — 1 3
Grey metal stone, the top ied 4nd 3 Strong white post - &S— 6
with girdles Grey metal stone — 4 6
White post. Shield row i - 13 — 10 | Strong grey post (fi leg
(the Main post) hin . ° _— 8S—
Suretp row Coat, B. t 5 3 Strong grey post : : 6. he le
(High main at Sheriff Hill) Whin — 3 8
Whitish grey metal stone with ; 6 3 o Grey and white post mixed w ay 6 5 6
post girdles ‘ whin :
Grey post . 2.3 5| Blue grey metal stone mixed fa ate
Grey metal stone . » — 8—y]_ with whin girdles
White post A ; owe al Coan, the Hurron’s Seam. E.
Grey metal stone ° - 3 2—J] (Five quarter and Six quar aye) 1,—
Black grey metal stone. » — 1 4] Coalat Sheriff hill.
Coax, the Hann Coat Sram we 4 9| White post 5 10
(Stone Coal at Sheriff hill) |Coat F. (20 inch Seat) — 1 8
Dark grey metal stone mixed hg hey Blue metal stone ek cles ale
with Coal . | Grey post mixed with whin -_ &8——
Coax, the Brass Coat Seam D. ' LOY r= Blue metal stone « 1 5 —
(Yard Coal at Sheriff hill) Main Coat. G. The Low }_ 3 6
White post » lL 2 2 Mats at Sheriff hill 4
Grey metal stone with girdles -— 4— - —
Total 96 EB 2
—
——
Carried forward 58 3 —
VOL. Iv. G
50 Mr. N. J. Wincu on the Geology of
Section of the Strata at Grienfield Colliery, half a mile West of
Aukland.
Fth. Yds. Ft. In. Fth. Yds. Ft. In.
Soil : . .- —— 19 Brought forward 21 1 2 2
Clay : : -_- le Sill ° : _—-— 2
Blue metal : i i Grey metal stone 2) She Lede s6
Grey metal stone - 1 1—— Strong grey stone —— 1 9
Strong grey metal —— 2— Blue metal and metal stone 3 — — 6
Blue metal : ee Dark blue metal « “peep myo
1 Coat 4 : .—-——— @9 Black metal stone _—-- 1
Sill : : - —— 1 6} 7 Coat , , _—--—--— 9
Grey inetal stone and 1 1 6 Band : : -_—--—— 9
blue metal : t en 8 Crow-CoaL ot oe — fh 1h96
Strong grey post - 1——— Grey sill - — 12 6
Blue metal : -— 1 2— White post . ~ 1 ie
Black metal stone — 1——|! 9 CoaL ; -_—---— 9g
2 CoaL ‘ — 1—— Grey metal with brown? _ 1 9
Sill s ; . 1——— scars : t Ix
Grey metal stone oe ek wee ae Grey metal stone with post— 1 — —
Grey post : — l=" 3 Strong white post . - 2 1— 6
Grey metal ; - — 1— 6 Blue metal _—-— 2S
Brown post ° oes BIG Strong grey metal OLIN Bi) g
3 Coa. : 4 - —— 1 6 Blue metal -—-— 26
Sill . : ot YE Strong grey metal stone 1— — —
4 Coat ° . - —— 1 6 Blue metal : -—-— 1° 9
Sill . . -_—- |l—— White post 3) 72°06
Grey metal : - LP 23 Blue metal - 4 1 tq a9
Metal stone A - l——— Black swad : - — 1— 6
5 Coar : ° - —— 1 —1]/10 Matin Coat . . hy) B10
Grey metal ° - 2— 1— -—
6 Coat ° . -_—-—-— 8 Total 46 — 1 6
Carried forward 21 1 2 2 |
Section of the Strata at Cockfield Colliery.
Fth. Yds. Ft. In. Fth. Yds. Ft. In,
Soil : : —— 1— Brought forward 16 — 1 —
Brown stony clay 1— — — Grey metal stone - 1—— 9
Grey post : >; 2— 1 9 Whin : - - ——— 10
Brown and white post . 3 1 1 3 Grey post 5 -_—- 1——
Strong white post -—-— 29 Whin ; - —-—— 6
White post . » 2 1—— Grey metal stone with 9,358
Grey metal stone - — 1— 6 girdles : f!
t CoaL ° ° -— 129 Dark blue metal —— 1l—
Grey sill. ° - —— 2—]} 2 Coar - . - lt-—-——
Grey metal stone - 3 1 2— Grey sill. . . —— 9
Black stone mixed with 2
Coal ia : vena Total 22— 1 6
Carried forward 16 — 1
Northumberland and Durham. 51
I have now concluded the most important of the geological
observations I had to make upon the Coal-field, and it remains only
to give some account of the mineral springs that occur within its
limits, and of the deleterious gases to which the mines are subject.
The mineral springs have been found either bursting out at the
surface, or have been discovered in the shafts of mines, and in the
dykes that intersect the strata. Those impregnated with common
salt have been noticed in the pits at Walker, Wall’s end, and Percy
main, and in most of the deep mines between Newcastle and Shields :
on the Wear they have been found at Birtley and Lumley-thick,
and appear rising to the day at Ouston 1 mile west of Birtley, and
at Butterby near Durham.
The spring at Walker issues into a deserted shaft from a bed of
slate-clay at the depth of 55 fathoms; but being dammed up rises
33 fathoms higher to within 22 fathoms of the surface, and 15
fathoms of the level of the Tyne. It is pumped from a reservoir in
the pit for the manufacture of soda, the salt obtained in the inter-
mediate process being exempted by an Act of Parliament from the
salt duty. The following is the analysis of this water by Mr. G.
Woods.
Contents in 1000 grains of water.
Dry muriate of soda . . . . 32
Dry muriate of lime . . . . 10
Muriate of magnesia . . . )
Carbonate of lime .
Carbonate of iron . . . .
SC es ae a
43 grains
A little carbonic acid gas.
GZ
52 Mr. N. J. WincnH o2 the Geology of
About thirty years since a brine spring was discovered at Birtley
colliery 76 fathoms below the surface, in driving a water level through
a slip of 43 fathoms throw. The spring being found to produce
26400 gallons of water in twenty-four hours, extensive salt works
were erected on the spot, which are still carried on with success.
Within 50 or 60 yards north of the slip, from which the spring
issues, the Birtley dyke before mentioned crosses the strata from east
to west, casting up the coal measures on the northern side 29 fathoms;
and the slip having a south-eastern direction probably meets the
dyke and is a branch from it. The water level is driven in a bed of
blue shale containing ironstone in beds and in nodules. The ana-~
lysis of the water by Mr. G. Woods is as follows. *
Contents in 1000 grains of water. grains.
Dry muriate of soda. . . 87
Dry muriate of lime . . . . 43
Muriate of magnesia. . . .
Carbonate of lime . . .
Carbonate of iron at :
Siléag 1)" ee 0) 8, Bary
131
A little carbonic acid gas.
Before the publication of Camden’s Britannia in 1607, a brine
spring had been observed to issue from the rocky bed of the Wear
at Salt water Haugh near Butterby; for in that work it is first
mentioned. In 1684, Mr. Hugh Todd drew up an account of this
* The carbonates, small as is their proportion, are sufficient to make the water appear
turbid, when viewed in the large reservoirs at Birtley. They are very readily thrown
down by the addition of quick-lime, and this method of purifying the solution is always
pursued in that salt-work. The brine leaves no incrustation upon the evaporating pans.
Northumberland and Durham. 53
and other springs in that neighbourhood, which was addressed in a
letter to the Bishop of Carlisle, and inserted in the Philosophical
Transactions. ‘The spring continues to flow from the crevices of a
basaltic vein for the space of 50 yards in length by 10 in breadth,
and in summer, when the water is low, tinges the rocks red, and
deposits a crust of salt upon them. The brine of this spring contains
carbonate of iron, muriate of soda, and sulphate and carbonate of
lime ; but as it becomes mixed with the fresh water in issuing from
the rock, the proportions of the mineral ingredients have not been
well ascertained.
Within the distance of 200 yards from this spring two others of
very different natures rise from bore-holes in the coal-measures.
These are situated in a small dell, and according to Mr. Todd were
discovered at the depth of 123 fathoms.
The spring furthest from the river is called the sweet well, and
contains according to Dr. Clanny a small quantity of lime held in
solution by carbonic acid.. Half way between the sweet well and
the Wear a sulphureous spring issues, and from the following
analysis by Dr. Clanny, it will probably be found to possess valuable
medicinal properties.
Contents in a wine-gallon of water.
Muriate of lime . . grains 5
Muriate of soda .. . . 56.
Muriate of magnesia. . . 4.
Carbonate of lime 8
Sulphate of lime 3
Gascous Contents.
Carbonic acid gas . Cub. In. 8
PUIG, BAS ek ie eo os
Sulphuretted hydrogene . . 11. 5
54 Mr. N. J. Wincn on the Geology of
Chalybeate springs, some of which deposit large quantities of yel-
low ochre, are common in every part of the Coal-field ; and a water
which flowed through the wooden pipes at Walker colliery, used to
let fall a copious precipitate of gypsum. The substance formed
during the twelve working hours of the mine was black, but at
other times was as white, and had the same degree of hardness as
chalk. A layer formed in twelve hours was about 3's of an inch in
thickness. Specimens of this sediment are to be found in many
cabinets, but are now no longer to be procured, the high main coal
being there exhausted, and the colliery laid in.
The choak damp, the fre damp, and the after damp or stythe, are
the miner’s terms for the gases with which the coal mines are
affected ; and of these the second both from its immediate violence
and as occasioning the other kinds of damps is the most to be
dreaded. The accidents arising from it have become more common
of late years, but it should not for a moment be supposed that they
arise from any want of skill or attention in the professional surveyors
of the mines. The following seem to be the causes in which the
gas originates, :
Ist. The coal appears to part with a portion of carburetted
hydrogene, when newly exposed to the atmosphere ; a fact rendered
probable by the well known circumstance of the coal being more
inflammable when fresh from the pit than after long exposure to the
air. 2d. The pyritous shales that form the floors of the coal-seams
decompose the water that lodges in them, and this process is con-
stantly operating on a great scale in the extensive wastes of old
mines. In whatever mode we suppose the gas to be generated, it
is disengaged abundantly from the High Main, but more particularly
from the Low Main coal-seam, and that in a quantity and with a
rapidity that are surprising. It is well known that the gas frequently
Northumberland and Durham. 55
fires in a shaft long before the coal-seam is reached by the sinkers ;
and that the pitmen occasionally open with their picks crevices in the
coal or shale, which emit 700 hogsheads of fire damp in a minute.
These b/owers (as they are termed) continue in a state of activity
for many months together, and seem to derive their energy from
communicating with immense reservoirs of air. All these causes
unfortunately unite in the deep and valuable collieries situated
between the great north road and the sea. Their air courses are 30
or 40 miles in length, and here as mignt be expected the most tre-
mendous explosions ensue.
The after damp or stythe, which follows these blasts, is a mixture
of the carbonic acid and azotic gases resulting from the combustion
of the carburetted hydrogene in atmospheric air, and more lives are
destroyed by this than by the violence of the fire damp.
To guard against these accidents every precaution is taken, that
prudence can devise, in conducting and in ventilating the mines.
Before the pitmen descend, wastemen, whose business is to examine
those places where danger is suspected to lurk, traverse with dint
mills the most distant and neglected parts of the workings, in order
to ascertain whether atmospheric air circulates through them. Large
furnaces are kept burning at the upcast shafts, in aid of which at
Wall’s end colliery a powerful air-pump, worked by a steam engine,
is employed to quicken the draft: this alone draws out of the mine
1000 hogsheads of air in a minute. A kind of trap-door, invented
by Mr. Buddle, has also been introduced into the workings of this
colliery. This is suspended from the roof by hinges, wherever a
door is found necessary to prevent the escape of air. It is propped
up close to the roof in a horizontal position; but in case of an
explosion the blast removes the prop, when the door falls down and
closes the aperture.
56 Mr. N. J. Wincu on the Geology of
It may be desirable to give an estimate of the quantity of coal
that is annually received from the Coal-field. The annual shipment
of coal for’a series of years from the Tyne, the Wear, Hartley and
Blyth will be found in the appendix, No. 2. From these it appears
that the quantity shipped
Irom the port of Newcastle, in the year 1813, was of Datanirr 598,773
chaldrons* . . 3 Tele Ew Ae On. caeeaRents
From the port of paiMbHand om Seen. 0) OL Re 2s Oe ay
From Hartley and Blyth, in the year igi. wis shaogo gt pols @B,908
+The quantity shipped annually from the four ports being about. . 983,698
The quantity vended from 35 Landsale pits in the county of Dur ere by 78,442
Was in the year (S08 yo ec ee Bas
The quantity consumed in Newcastle, Sunderland, North and
South Shields, Hartley and lige was computed by Dr. Maca 190,000
in the year 1801,at . . . elo od: ye] eudi sige wht
But there are no precise data for calculating the home consump-
tion of the two counties. About thirty years ago a practice was
adopted at the pits, where the coal was of a fragile nature, of erect-
ing screens to separate the small from the sounder coal. This system
is now become universal, and immense heaps of coal are thus raised
at the mouths of the pits. These soon take fire from the heat of
the decomposing pyrites,|| and not less than 100,000 chaldrons are
thus annually destroyed on the Tyne and nearly an equal quantity
on the Wear. It is greatly to be desired that some use should be
found for the small coal in order to prevent so great a waste.
* The Newcastle chaldron == 53 ewts. or 4$ of the London chaldron,
+ It appears from the table given in the Appendix, (No. 2.) that in the year 1813,
970,901 London chaldrons of coal were imported into London. Deducting from these the
50,000 chaldrons brought by canals from the midland counties, there will remain 920,901
London chaldrons == 491,147 Newcastle chaldrons of coal imported by sea into London,
f See his Tract on the Coal trade.
|| Beneath the heaps that have taken fire, a bed of blackish brown scoria is formed,
which greatly resembles basalt, and is used for mending the roads.
Northumberland and Durham. 57
IV. Lead-mine Measures.
The metalliferous or lead-mine measures form the northern and
western boundaries of the Coal-field. This formation enters Nor-
thumberland from the northern side of the Tweed, and constitutes
its southern banks from its junction with the Tiviot at Kelso to the
sea. In a south-eastern direction it follows the coast from Berwick
to the Coquet for 32 miles. The porphyritic mountains of Cheviot
interrupt it towards the west for about 20 miles; but having passed
the southernmost point of that ridge it stretches across the whole
breadth of Northumberland, and is spread over the adjacent borders
of Cumberland, Durham, Westmoreland and Yorkshire. Jt is ter
minated towards the west by the red sandstone near Brampton and
Melmerby, about 54 miles from the sea at Tynemouth and at Seaham.
The characteristic features of the north-eastern part of this district
are gently swelling hills, heightened occasionally by mountain caps
of basalt, and then assuming a rugged and broken aspect on their
summits. ‘Towards the western part of Northumberland it forms
sterile moor-lands and exposed sheep-pastures, being still accom-
panied by basaltic eminences: the river vallies, however, that inter-
sect these wastes, are fertile and picturesque in a high degree. Ifa
line be drawn across the island through Newcastle and Carlisle, the
highest station between the German ocean and the Irish channel is
not more than 445 feet above the level of the sea; upon this spot
the village of Glenwhelt is built.* On the banks of the South Tyne
* From Tynemouth to Newcastle .. 000 oes osec0n
Plate ea: oi, oe) ee 8 slate clay and sandstone —_—
Freestone (finegrainedsand-2 7 __ |_|} alternating) .
OS lly ia $ = Freestone ry Ae
Coarse hazle_ . 5 . 1. 1——!'i Plate ~ ; ° TE ah oes
Plate and Blue whin . Ll — — —|| Hazle or Slate . . 2 bmw
Plate and Grey beds - —— 2 —!||Plate or Famp a
Hard stone and Whin . l— 2 —'|/Hazle and Plate ° 2i1.——
Plate and Whin A - Ll 1 2 —!! Plate ‘ ‘ - . 4D) — eee ee
Plate . : ° - 2 1 ——+| Hazle or Slate . » li-—
Millstone grit - 5 —— —|| Plate and Grey beds » Li-—
Plate . , » «+ 4 1 — —| Thin stratum of Grey beds. 15 — —~ —
Carried up 36 — — — Fathoms 74 — — —
H 2
60 Mr. N..J.. Wincu on the Geology of
- Section of the Strata at Beldon above Blanchland on the Derwent.
Fs. Ft. In Fs. Ft. In
Low grit (A) wht) > bees wee up 32 4—
Pebbles ; ; ° - ——-—||Hazle . - ~_ —- 4—
Plate. - < - . 2 § —|iPlate. “Tigh ee
Lime (A 2) . ’ — 3 —||Coaxand Hard Coal sill | 14—
Coa, . . : . — 1—Greybeds. FM leet oc
Plate . > » 1 — —4\ Plate and Coal A - 14—
Hard strings ° > . — — —]| Low Coal sill, Sandstone) Bi ee oigeem
Craig’s sill (B) . : . 4 2—||Plate . 4 - 1——
Plate. 4 ; 5 - 1 5 —/Hazle . = - A -_— 3—
Cockle shells . ———||Plate . 2 g wv) tees
Pattison’s sill (C) . 2 2 4 6/||Great Lime (E) 3 . sa mes
Biateis . : : . 4 1 6/|Tuft . - . _—- 4—
Hazle . . . — 8-—||Grey beds . . . eins
Plate -. 3 F 9. —=1| Hazle «. 3 d Piel Lie! Lape)
Hazle 4 3 —j|Plate . s cid Ree Te
Plate. 1 2 —|| Hewitson’s Lime (F) — 4—
Little Lime and Black bed (D) 1 3— janes
Fathoms 59 4 $3
—
9
tS)
RAS
|
‘ Carried up
Section of the Strata at Shildon above Blanchland.
Fs, Ft. In. | Fs. Ft. In-
Hipple ; : _ 7-— Brought up 69 3 3
Plate . C : 4 - 7 — —||Hazle ! : 2 _ — 38—
High grit . ° - 8 3 6//Plate - . : - 2 1—
Plate and Coal C - — 8 3/!Hazle - : ss -_—- 4—
Plate and White sill > : 1 DieOP ate : 2 5 oe
Plate, Coal and Plate - 38 — 6} Little Limestone (D) 3 gs Qe
Low grit ad , - 11°— 6} Plate and Coal ° : al ee
Plate - . c - 1 4 Q9}Coansinun. . : 2% Ses
Pebbles ‘ 1 — —||Plate . : 2. 2——
Plate, Lime, Post and Hazle (A2) 1 4—'Coat,&e. . ° ° -_ —- 3—
Crag sill (B) . ‘ - 4 2—j||Low Coarsitt . . - tt @—
Plate . ; Ve - 4 3 6} White sill 5 c - & =
Pattison’s sill (Cc). . 6 4 6||Greybeds . « “ -—-—— 8
White sill . x : - %2—-—}/Plate . 4 F : - L——
Hazle... ; 4 5 —|Great Limestone . : ———
Plate . : . 4— —
Fathoms 91 — 2
Carried up 69
bo
co
Northumberland and Durham. 61
Section of the Strata from Brandon Wells to Westgate in Weardale.
Fs. Ft. In, Fs. Ft. In.
Great Limestone (E) . - i—— Brought up 44 — 1
Tuft or Water sill ° + 1 3 —||Three yard Limestone Mo pa Pee
Plate : . - 2 — —||Plate . -_— 3—
High quarry Hazle ‘ - 1 3 —}Hazle . : he Oe}
Plate . - — 3 —||Plate > ‘— 3—
Low quarry Hazle . 2 — —|| Limestone (H) 3 3 5
Plate - 9 — —]} Plate . ._—- 2—
Four fathoms Limestone (F) . 4 — —|| High Slaty hazle . - 1 56—
Plate : . - — 3 —|/ Plate - Il——
Hazle . . - 6 1 3} Low Grey beds Slaty hale . 1 3—
Plate . . ~ "5 4-10) —
Fathoms 62- 1 —
Carried up 44 — 1 —_——_
Section of the Lead-mine Strata on Aldstone Moor, Cumberland.
Fs. -¥. Ft. Im Hs. Y¥. Et. In;
Grindstone sill ° - 4—— — Brought up 67° 1 — —
Plate : : . . 6 — — —||Plate ° - §———
Hazle . 3 : . 1 — — —} Lirtte Limestone (D) 6 Ea ee
Plate : . - 2— — —}\Little hazle . - — 1,°2°—
LimEsTONE (a) ° 1 — — —]| Plate c - 2—— —
Crow Coal occasionally Coal occasionally
Hazle or Upper Coal sill 1 — — —/!High Coal sill. (Hard grey)
Plate : . 8 — — — saudstone with specks of > 1 1 1 —~—
Hazle . ’ 1 1 1—j mica. ° . .
Plate ° . . - 2 1 — —} Plate ° - l—-——
Hazle . - &2— 2— Coal occasionally
Plate 6 ° - 1 — — —|]| Low Coal sill : ._ %———
Upper Slate sill. : . 4— — —|| Plate 3— 2—
Plate : ~ ti1i—— 'Tumpiers and Great Lime- tone. 1
Lower Slate ane . 4— — —|]) stone (BE) . : '
Plate 5 — 2 —|!Tuft or Water sill 1— 2—
Whetstone sill. (Fine arained 14 Plate 3 . : » 2 1r——
Micaceous sandstone , ~~ || Limestone post . - — 1 1i—
Plate. ( Ferruginous sandstone) 2 — — —|| Quarry hazle : - 4—-——
Tron stone with Coal 1— 1 —|! Plate.
Freestone with Iron pyrites. 5 1 — —| Indurated bluish clay with
Plate pe ge 6 — 1 —|| lamine of hard stone wat 5
Girdle beds — 1 2 —/ _ iron pyrites , :
Plate 3 1— Great Girdle bed... i
Pattison’s sill or hazle (C) “4
Very hard grey sandstone > 1 1
with specks of mica
Four rAtuoms Limestone (F) 4 — — —
Nattras gill quarry hazle_ .
_ Coarse grained stein
i Plate : - . » 6———
Carried up 67 1 — — the &e
Carried up 121 — 1 —
62 Mr. N. J. WincH on the Geology of
Fs. Y. Ft. In Fs. Y. Ft. In
Brought up 121 — 1 — Brought up 145 1 — —
‘Two FATHOMS pager ne! 2—— — Coal occasionally
Plate - — 1 1—+} Plate - 1— 2@—
Arthur’s Pit quarry sill . 4— — —] Cockreguent Limzstons « — — 1 6
Plate S : a. da ogee “ . »- 2 1——
LIMESTONE (H) - — 1 2 —|} Plate " - : -— 1j-s
Hazle . . ‘ . 2— — —|| Limestone - - ‘ —- |) 16
Plate 5 - 1 1— —| Plate » 41——
TUMBLERS aid Scan Limestone 9 — — —|| Tyne Bottom Limestone oon) et ae
Plate . ° . -—- l-— —_——_—____——-
Grey beds : : - @— 1— Fathoms 159 — 1 —
Carried up 145 1 — —
Section of the Lead-mine Strata at Dufton, Westmoreland,
Fs. Ft. In. || Fs. Ft. In,
Great Whin sill Beat - 10— — Brought up 33 3 —
Plate - 3 — —|Great Hazle . . oO——
Hazle 3 - 2— —|\ Plate és A - 4—-—
Plate . : - 2 — —|Sminpvy Lime : » 4i1—
Hazle ; “ - 3 ——|Hazle - . A 1——
Plate i - 1 1 —j] Limestone _ - 41—
Jew Limestone A - 3— —!] Hazle ‘ a eee
Plate a . - 1 — —|| Limestone F ES ee
Hazle 5 6 ; 5 — —|| Plate : . - 1i—_
Plate A ; « 1 J —|\ Limestone ‘ pee ee es
Lirtte Limestone . >» 1 —-—|/Plate oP ek LL
Hazle r A > 1 1 —|| Rosrnson’s Caan ecient Ae
Carried up 33 3 — Fathoms .78 4 —
-~-
Section of the Strata observed to crop out from belowthe Dufton Sills,
Fs. Fe. In. Fs. Ft. In.
Hazle 4 : ol Moot ez Brought up 54 5 —
Plate 3 — 1 —}} Freestone B 2 arnt ilar gk Fa
Great Limestone or Ropar, a1 Plate 5 : - t——
or Metmersy Scar, . ~ “it Limestone. A - &——
Plate é A . 2 — —|| Hard freestone : Supe VS
Freestone F . 1 —- —]| Plate and Coal (7 inch seam) . 8 — —
Plate and Small Coal . - 1 — —']| Freestone > 5 . 6 y=
Lime 2 3 - 4——WGirdle bed ,.- : Pies a
Freestone i ; . 18 — — Limestone , oe eee
Plate 5 5 - kl 1 —!/ Freestone , see
Freestone . . « 1 1 —j} Plate, upper part black, lower
Plate ° . . @——H part reddish i A tremit
Freestone ; E cu l MS Old red sandstone
Plate ‘ _ - 1a ;
Fathoms 140 2 —
Carried up 54 5%
Northumberland and Durham, 63
Section of the Lead-mine Strata at Arkendale in Yorkshire.
Fs, Fe. In. Fs. Ft. In.
White grit. ‘ : 5— — Brought up 58 1 6
Coan. s F : . — 1 6]Girdles . é Be
Millstone grit : ° - 14 3—|/Plate . : : . - §$——
Plate. 2 4 4 . § — —1Chert or Iron beds : - &——
Lime. F s ‘ - — 2 —} Red beds 4 4 - 2 —i—
Plate + 2 ; . F§——lPlate. P > 3 . L— —
Lime . P ‘ Pp - — $3 —/|! Black beds . - J - 2&2 3=
Plate . ‘ Z b . 1 — —!/ Plate s bs - es ss
Lime . é A ‘ - — Slime . F : E _— —
Plate . . i (4) sty =—'|Plate ss ms . A -_—- 4—
Flinty chert : - 2 4—lMain chert . . ° 3— —
Plate . ‘ , - — 1 —]| Main lime ‘ P . 12 — —<
Crow chert. : . » 1 — —|{ Dead grit . . » Im —
Plate . P é A - 1 3 —}) Underset chert - , » 6——
Second Crow chert : - 2 — —]| Underset lime ‘ : . s——
Crow lime. . : - 2 — —|Underset grit : . > 6——
First Soapy grit . . 1 — —||Girdle ° . . »- 2 3—
CoAL BED 4 : 4 — 1 —|Grit s = - - 12——
Second Soapy grit 1 1—Plate. . . . » 5§——
Plate . z “ 3 1 2—j||Lime . “ : > (GF— eer
Grit “ . . ‘ 11 — — ——__
eleeabie lit Fathoms 136 2 6
Carried up 58 1 6 ——
The uppermost of the beds detailed in these sections consist of
sandstone and shale, and they are the first that rise from beneath
the coal formation. ‘The most remarkable of the sandstones are
1. The slate sill, a fine grained, micaceous, slaty rock of a grey colour,
used as a roofing slate in many villages of Northumberland and
Durham. It is the uppermost bed in the section of Hely field.
2. The /reestone sills: these are fine grained sandstones frequently
containing vegetable impressions.
3. Hard ferruginous fine grained sandstones called hazles by the
miners. The sandstone in the section of Aldstone moor, called
nattras gill hazle, is however coarse grained. These are sometimes
slaty, and occasionally bear the impressions of bivalve shells.
4. The millstone grit; a coarse white sandstone composed of
small angular grains of quartz, with rounded pebbles of the same
64 Mr. N. J. Wincu on the Geology of
substance imbedded in them. This is one of the uppermost strata
on the Derwent, where it crops out, and is quarried for millstones.
The quarries are on Muggleswick Fell, and also between Wol-
singham and Stanhope in Weardale. ‘The thickness of the rock at
Mugeleswick is about 5 fathoms. The hilly district of the lead
mine country affords but one stratum of this rock, which crops out
before it reaches Aldstone moor or Allendale. It is probably the
same bed which is found .in the section of Arkendale. A similar
rock is found in the north-eastern part of Northumberland at
Scramerstone four miles south of Berwick, and at Craster near
Howick; and with this durable material the castle of Dunstanborough
is built. The grey millstones of Muggleswick are employed for
grinding rye, but those brought from Derbyshire are preferable in
quality.
5. The grindstone sill, a fine grained yellowish sandstone, which
on Aldstone moor, Coal cleugh, and Allenheads is the uppermost
bed, and is found near the surface at Nent head and on the summit
of Cross Fell. On Aldstone moor its thickness is about 4 fathoms.
Grindstones, greatly inferior to those of Newcastle, are made of it
for home consumption.
Below the limestone in the Aldstone moor section the following
other sandstones may deserve notice.
1. The whetstone sill, a fine grained micaceous sandstone, which
may be seen at this day at Burtreeford.
2. The iron-stone sill, a ferruginous sandstone, containing iron
pyrites in abundance.
3. Firestone, a porous fine grained sandstone, used for the con-
struction of furnaces, and varying from 5 to 6 fathoms in thickness.
4. Pattison’s sill, a very hard grey sandstone with specks of mica.
5. The coal sills, many of them resembling the last.
a iii
Northumberland and Durham. 65
6. The water-sill, called also tuft, a very porous light-coloured
sandstone, of a soft texture from the loose aggregation of the small
grains which compose it.
The beds of sandstone are thickest towards the lower part of the
series. Thus at Hely field the freestones are 7 fathoms thick, the
most considerable of the grits at Shieldon about 11 fathoms, the great
hazle at Dufton 10 fathoms, and three of the freestones in the section
below that of Dufton 18, 26, and 30 fathoms respectively.
The limestone beds are the most characteristic of this formation,
and are the most important to the miner. Of these there are 21
beds in the preceding sections of which the aggregate thickness is
about 96 fathoms, that of the whole series being, as I have already
mentioned, about 458 fathoms.
The most remarkable are 1, the great limestone, the 3d in the
series, from 10 to 11 fathoms thick, consisting of three strata divided
by indurated clay. ‘The stone is a brownish black or dark bluish
grey encrinal marble in which bivalve shells are imbedded. It bassets
at Frosterley in Weardale, where large quantities of it are quarried
for agricultural uses and building cement, or for ornamental purposes.
It burns to a lime of a mild nature, highly valued as a manure, and
contains according to Sir H. Davy 96 per cent. of carbonate of lime.
2. The scar limestone, the 7th in the series, 5 fathoms thick,
resembling the great limestone both in its colour and organic remains,
and like it divided into three strata. This rock crops out in the
little river Nent, and forms the barrier at the cascade called Nent
force.
The aqueduct level, carried on by the Commissioners of Greenwich
Hospital, begins near Aldstone, and is driven at its commencement
immediately below this bed of limestone: it is now two miles long
from north to south.
VOL. Iv. I
65 Mr. N. J. Wincu on the Geology of
3. The cockleshell limestone, not exceeding 20 inches in thickness,
and next below the scar limestone. It is of a dark iron-grey colour,
and contains besides the encrinal fossil, oyster shells of the diameter
of 4 or 5 inches, and other bivalve shells. It crops out in several of
the small gills on Aldstone moor, where it does not exceed in thick-
ness 20 inches.
4, The Tyne bottom limestone, the 10th in the series, 21 feet
thick. It is an encrinal limestone, consisting of 3 strata, forming
the bed of the Tyne for 4 miles from Tyne head to Garrigill gate,
and is the lowest bed in which the mines have been wrought on
Aldstone moor, though nearly the uppermost at Dufton.
5. Robinson’s great limestone, the lowest in the Dufton section,
and 14 fathoms thick.
6. Melmerby scar limestone, the thickest in the whole formation,
measuring 21 fathoms in Melmerby cliff, where it bassets out. It
contains the encrinal fossil, and bivalve shells.
The beds of limestone have been observed to be more regular in
thickness throughout the mining field than those of shale or of sand-
stone.
The beds of shale or f/ate (as it is called) are very numerous, and
are found alternating with the rocks of limestone and sandstone.
They are seldom so thick as 7 or 8 fathoms ; but the plate sill, which
is the lowest bed in the section below that of Dufton, measures 10
fathoms. Shale alternating with sandstone in thin layers sometimes
forms beds of considerable thickness, (see section of Hely field,)
which are called grey beds: when containing laminz of hardstone
and iron pyrites it is called a girdle bed. Iron pyrites is found im-
bedded in the shales in great abundance, and in various forms; but
owing to the high price of fuel and the great distance from any sea-
port it cannot be manufactured into green vitriol to advantage. Clay
Northumberland and Durham. 67
ironstone is found in the shale, forming either thin subordinate
strata, or nodules; at Aldstone and in Teesdale it occurs forming
septaria with internal divisions, such as are represented in St. Fond’s
travels; and at the latter place it forms the cetite or eaglestone of
the cld mineralogists. It is more abundant in the shales of this
formation than in those of the Coalfield, but the only iron work
now existing within the limits of my map is that of the Tyne
company at Lemmington in the northern part of the district. The
Carron company formerly collected on Holy Island a part of the
ore smelted at their furnaces, but they have long since relinquished
this undertaking.
About the beginning of the last century, according to Wallis, an
iron manufactory was established at Lee Hall, in the vale of North
Tyne near to Bellingham. The director of it was a Mr. Wood,
son of the Irish projector of that name. The ore was plentiful in
the strata of a romantic precipice on the east side of the river, and
a good deal of bar iron was made from it; but it seems that char-
coal becoming scarce the work was relinquished. Large quantities
of slag are still found scattered over the surface, or forming con-
siderable mounds, wherever the Romans carried their roads or
fixed their stations.
The variety of carbonate of lime called satin spar, forms a
thin stratum in a bed of black slate-clay, which crops out at
Aldstone close to the brewery. The specimens are generally inter-
sected by veins of iron pyrites and slate-clay. Some buildings
stand upon the bank out of which this mineral was quarried, and
the proprietor to save them from being undermined has built a wail
close to the face of the rock; so that satin-spar is no longer to be
procured, and is become a scarce mineral.
There are few parts of the Lead-mine district. in which coal is
12
6&8 Mr. N. J. Wincu on the Geology of
not to be found, though the seams cannot be compared in mag-
nitude to those of the Newcastle formation. In the mountainous
parts of the district the seams are extremely limited in extent, being
soon squeezed out, as the miners term it, and seldom exceeding 20
inches in thickness. In the high grounds, near the sources of the
South Tyne and the Allen, Coarse or Crow coal abounds; and on
Aldstone moor five seams of this fossil are imbedded between
the grindstone sill and the Tyne bottom limestone: it does not
appear among the sills on the Derwent towards the east, or of
Dufton towards the west of Aldstone, but occurs near the summit
of Cross Fell, where no other is to be met with. Crow coal generally
rests upon a thil or plate of slate-clay ; but the beds being very un-
certain in their extent are seldom noticed in the Lead-mine sections.
They are worked at a small expense by means of drifts into the
sides of the hills, and as fuel is scarce in the mountainous district,
Crow coal becomes an object worthy of attention.
This mineral is of a dirty sooty-black colour, and contains much
sulphur, which renders its smoke extremely offensive. At Aldstone
it is mixed with clay and made up into balls, which yield con-
siderable heat on burning, but emit scarcely any flame.
On leaving the mountainous district, the seams of coal are found
improved in point of quality and thickness, and it will appear from
the following localities, over what an extent of country that mineral
is found.
It occurs at Stublick, six miles south-west of Hexham; at Wall
near Fallowfield ; near Bellingham on the North Tyne, where many
good seams are found; at Kerryburn near the foot of the Carter on
the borders of Roxburghshire ; in the vale of the Reed; at Elsdon;
at Woolcoats on the moors near Harbottle castle; at Hesleyhurst ;
at Healy-coat ; near Carlington castle; at Newton; at Shilbottle ;
Northumberland and Durham. ‘69
at Elginham; near Craster; near Beadnell; near Belford; and at
Tweedmouth in the vicinity of Berwick.
In the north-eastern part of Northumberland, near the sea, the
seams are tolerably thick, and very good in quality; that of Shil-
bottle for instance, which supplies Alnwick with coal, (see the
section below.) The mines are usually of inconsiderable depth in
comparison of those in the Newcastle coal-field ; that of Shilbottle
is one of the deepest, measuring 45 fathoms. That of Newton
(see the section page 71,) measures 16 fathoms, and some of
the pits near Berwick only 15 fathoms. The mines of Stublick
and Wall, on the borders of the mountainous district, are severally
16 and 19 fathoms deep, and each contains three seams of coal.
(See the sections p. 70.)
The coal alternates with slate-clay, limestone, and sandstone, and
at many of the places where coal is worked, limestone is also quar-
ried. Inthe maritime district, from the Coquet to the Tweed, the
measures dip to the south-east, and unlike the beds of the New-
castle coal-field undulate with the surface of the earth.
The following sections will give some notion of the measures
that accompany the coal to the north of the mountainous district.
Section of the Strata at Shilbottle Colliery, 24 miles South of
Alnwick.
Fath. Yd. Ft. In. Fath. Yd. Ft. In.
Clay é s ¢leQe dort — Brought up 28 1 1 10
Freestone : [0 2c — Main slate ry a
Blue slate f (+) — Blue. limestone 3—- — —
Blue limestone i Thil — j|— —
1 Coat oe Freestone Li. —
Thil ———— ih — Metal F 1— — —
Freestone Tey. (oe Blue limestone — — 2—
2 Coat — — —«&J — Thil L— Ir —
Thil es 6| Ironstone — —— 6
3 Coa —— 1—| Rough stone 2— — —
Thil ey) i — ne AA re ——'° 2 7
Main freestone eee PN ——
——a Fathems 45 2 1 11
Carried up 28 1 1 10)
70 Mr. N. J. Wincu on the Geology of
Section of the Strata at Wall, near Fallowfield, 3 miles North of
Hexham.
Fath. Yd. Ft. In. | Fath. Yd Ft. In.
Soil _—— 1l— Brought up 17 —— 2
Sand and bluish clay ‘ 312 with Brown and grey metal t iP yi es
with hard tumblers | with sand skares
Sand —— 1—' Blue metal with skares t p%
Strongish blue clay (stony )112— of Coal :
Soft grey metal with Q “pied he Coit : -—--— 19
whin girdles . | Grey metal. aa = 2
Rombly* limestone —— 2 6] 3 Corr ——-— 5
Strong thready blue at yee I Grey metal skared with hat alls ie
limestone t Coal
Blue skared metal ——— 4' Grey metal inclining to
Strong grey metal stone -—- 1 1 2. metal-stone near the — i—
1 Four Coat. -—-— 12 bottom
Grey metal. BE hae ce ———_—_—_——
Brown and grey — a jail Fathoms 19 1 1 6
post °
Carried up 17 — — 2
* Containing Pebbles.
Section of the Strata at Low Stublick, 54 miles South-west of
Hexham.
Fath. Yd. Ft. In. Fath. Yd. Ft. In.
Soil and romble oni) uke Des. Brought up 17 —— @
Grey metal stone with } Sp Lae Gel Grey metal. ._—-— 2
girdles and water Whitish grey post viediana b 2
White and grey gullety Blue grey metal —— 2—
post, andsetawaythere 3 1 2 — White post mixed with. eer
watert . . whin °
1 Coat with water _—-— 24 Soft sandy white post . 1— o1—
Grey metal with girdles 1 — — — Dark grey metal ~ . — 1 2 6
Grey metal. - 1—— —} 5 Coan with white skares ——— 2
2 Coat 5 -—-— 11 —_—_——_-——
Grey metal. -_—-— 2— Fathoms 16 — 1 2
34 ren ‘ _—-—— 7 —_——_—
Four Coat -_—-—— 3 ;
Grey metal . -_—-—— 9g Seams now working, 1814.
4 Coat with white spar . ——— 5 At 12 fathoms . . 34 inches
— 16 eth) one,
Carried up 17 — —2 20 —— . « 45—
+ See Notes, pages $3 and 47.
Northumberland and Durham.
71
Section of the Strata at Allendale Town, 7 miles South-west of
Hexham.
Fath. Yds. Ft. In. Fath. Yds, Ft. In.
Soil , . = 6 Brought up 18 1 2 —
Stony clay . 1 — — —]/Strong white post with me > ies
Rombly post —— 2 6] girdles :
Strong grey and brown post 2 1 — —||Grey metal stone with hard ep al
White grey post 2 1 2 31 girdles
Dark grey post. 4 1— 3]W hin (4 days) — 17
White grey metal with post ea gol, es Strong dark grey metal wy 9125
girdles whin girdles } {
Dark grey metal stone 1— 1 Blue whin (got 24th June,
White post mixed with whin. 1 — — —]} and continued to 6th t- 1— 8
Dark grey metal — 1—] July) :
White grey metal with nee Barone "4 rs
post girdles Fathoms 26 1 2 8
Carried up “18. 1 2—
In the colliery of Newton, situated 3 miles north of Felton and 6
from the sea, the strata dip to the south-east 1 yard in 5.
The following is a section which I received from the overman of
the mine.
Fath. Ft, In
Clay . . —_ —
Sill of limestone, consisting ‘of 5 strata ; that near the A
middle containing impressions of bivalve shells is
Red sandstone and shale. 8 — —
Coal of an indifferent quality, worked for burning lime — 2—
Five yard limestone : 2 3—
Sandstone and shale . . -
Good Coal 3 : ° — 3—
Fathoms 16 — —
The organic remains found imbedded in the limestone shale and
sandstone that belong to the lead mine measures are the following.
In the limestone.
1. Light brown impressions of the turbinite madrepore (junci
lapidei) Parkinson vol. 2. tab. 6. fig. 1.
Frosterly and elsewhere.
In the great limestone at
72 Mr. N. J. WincH on the Geology of
2. Madrepora. See Parkinson, vol. 2, tab. G. fig. 3. in the same
limestone, and in a stratum resembling it in colour, situated on both
banks of the Tyne near Glenwhielt.
3. A grey limestone may be observed in detached masses on the
high banks above the East Allen composed almost entirely of a fossil
called madrepora flexuosa. See Parkinson, vol. 2. tab. 6. fig. 8. The
same reck also occurs above the bridge at Simonbourn,
4, Millepores, in a brown limestone from the neighbourhood cf
Aldstone.
5. Vertebral columns of the cap encrinite. Parkinson, vol. 2.
tab. 8. fig. 4.; from the same rock and locality as 2.
6. Bivalve shells from the same rock and locality as 2.
7. Pectinite and large ostree. In the cockleshell limestone, and
in the blue limestone quarried at Newton-Hall near to Corbridge.
In the shale.
1. Calcareous casts of the vertebral columns of the cap encrinite ;
(St. Cuthbert’s beads) Parkinson, vol. 2. tab. 8. fig. 4. In Allendale,
‘Weardale, &c. On the banks of the Greta, and in a stratum above
Tecket water-fall near Simonbourn; also on the shores of Holy
Island.
2. Impressions of pectinites about 13 inch in diameter: Aldstone
moor.
3. At Hairshaw and at other places on the North Tyne the shale
contains nodules of clay ironstone, and small muscle shells filled with
the same ore.
In the sandstone.
1. Impressions of pectinites on hard slaty sandstone (hazle) in
Allendale.
Northumberland and Durham. 73
2, Impressions of Arce and Anomiz. Sowerby, t. 35. On ferru-
ginous sandstone from Allendale and Teesdale.
S. Impressions of Euphorbie on Freestone from Aldstone and
Teesdale. Sowerby, t. 39 & 40. Parkinson, vol. 1. tab. 3. fig. 1.
Basalt occurs in the mining field either between the regular sills,
when it is considered as one of them, or, as it should seem, in
overlying positions. The great whin sill in the lead mine sections
does not consist of the whin of the colliery sinkers, but is really a
basalt, coarse-grained in texture, and composed of white felspar
and black hornblende, the latter mineral predominating, and giving
to the rock a dark greenish grey colour. This bed is placed in the
section at Aldstone at the depth of 159 fathoms, and at Dufton
is considered as forming the uppermost stratum ; the miners indeed
regard all the beds of basalt which occur in the mountainous dis-
trict as ramifications from the great whin sill; but I do not think it
certain that there exists this connexion between the beds of basalt
found at the two abovementioned places. The thickness of the
whin sill is very irregular, being only 6 fathoms in some places
and 20 or even 30 at others. In point of situation it agrees re-
markably well with the toadstone of Derbyshire.
By far the greatest assemblage of basaltic rocks in this part of
the district is met with in Teesdale from the source of the Tees to
Eglestone. At Caldron snout, situated on the moors 10 miles
above Middleton, a basaltic ridge crosses the river, and occasions a
succession of cascades for the space of 596 yards, which form a
fine contrast with the pool of still water or wheel above the falls.
It was here immediately under the basalt that the Rev. J. Harriman
discovered small white garnets? crystallized in dodecahedrons, and
VOL. Iv. K
74 Mr. N. J. Wincu on the Geology of
imbedded in a thin stratum of pale red hornstone or chert with
particles of calcareous spar. Vide Sowerby, tab. 120.
Near the steep acclivity which terminates Cronkley Fell, another
range of basalt interrupts the course of the Tees, and causes the
cataract called the High or Mickle force, where the water is pre-
cipitated from the height of 56 feet. The rock which here crosses
the river is apparently an overlying mass of coarse-grained grey
basalt, the hornblende and the felspar which compose it not being
intimately blended. It rests upon the lead-mine sills, and shoots
on the banks of the Tees into regular columns of considerable mag-
nitude and elevation. A few miles below this cascade, and about
three above Middleton, perpendicular basaltic rocks again form
the banks of the river. To these, iron chains have been fastened
for supporting Winch bridge. This remarkable structure (if it
can be so called) is a plank 2 feet in breath with low hand rails,
suspended 56 feet above the Tees, which is here 63 feet wide.
Some miners contrived it for the purpose of passing from the county
of Durham to Holwick in Yorkshire.
In the fragments of basalt which are found scattered over the
surface in Teesdale, and in other parts of the district, small grains
of yellow olivine and of greenish black augite are found imbedded.
Leaving the mining field at Jemming on the borders of Cumber-
land, and at Stagshaw bank near to Fallowfield the basalt appears to
fill dykes ; but in the range of hills between these places it seems to
form overlying masses.
In such overlying masses it bounds the lake of Shewingshields,’
and the rock on its northern acclivity which is nearly perpendicular
assumes a columnar shape. ‘The Romans constructed their wall for
many miles close to the edge of this natural rampart; it may
be seen at this day standing 4 feet high in many places. In the
Northumberland and Durham. 15
interstices of the basalt I have noticed ironclay of a brick-red colour,
and at Glenwhelt Mr. Fryer detected small veins of dark leek-green
talc in thin leaves mixed with iron pyrites and calcareous spar.
This fossil on being exposed to the action of the blow-pipe divided
into extremely thin folia, and changed from green to copper colour :
with the addition of borax it melted into a greenish black bead.
These overlying masses of basalt appear also at Barwesford on the
North Tyne, and are continued to the vicinity of Thockrington and
Bavington, to Kirk Welphington, and thence in a north-easterly di-
rection as far as Causway-park, north of Morpeth.
Proceeding further to the north, basaltic eminences form, a striking
feature in the country between Alnwick and Berwick. These emi-
nences have frequently been chosen for the sites of castles, as at
Dunstanborough, Bamborough, and Holy Island. The hills near
Belford, the rocks called the Staples which emerge from the sea at
the distance of six miles east of Bamborough, and the Fern Islands
situated half way between the Staples and the shore, are likewise
composed of basalt. -
At Craster near Howick, where the millstone grit is also found,
basalt was formerly quarried and shipped to London for paving-
stones. Craster house is fronted with this rock,
In the north-eastern face of the cliff, on which the ancient fortress
of Dunstanborough stands, the following series of strata is exposed
to view:
Columnar basalt - - from 8 to 10 feet
Gandatones s4..04 gic 97940
was constructed about forty years ago by the late Mr. Westgarth, agent to Sir Thomas
a
Blackett, and the following data taken on the spot will shew its power,
Column that works the Engine..................0... 20 fathoms
DiameterofthevBistonsj.seiacisetacle oehecihe lee viene 7 inches
Lengthof the Stroke sites. jocalens cee assed oe eee ee 5 feet
Diameter of the bucket that lifts the water............ 6 inches
Length of the column to be lifted ............0c000-- 19 fathoms.
Number of strokes per minute............... ae Siete 9 or 10
* Price of Common Lead. April 1814, £30 per fother of 21 cwts.
of Refined: Lead} iiss. aie icieis ass « 31 ditto
Of Fine Silver ease si 6\5 s\e,0-0 weinre 7s. 5d. per oz.
N.B. The fother on the Tyne is 21 cwts, On the Tees 22 cwés,
Northumberland and Durham. 83
The quantity shipped from Stockton is on an average about 3000
tons per annum. The whole of the lead mines in Great Britain
are estimated to produce from 45000 to 48000 tons per annum.
The minerals which occur in the veins of the lead-mine district
are the following.
Ores of Lead.
Galena.—Massive.
Crystallized in cubes, or with all the angles or edges of
the cube truncated or bevelled in various degrees, or in
octohedrons.
Occurs in cavities with fluor, and calcareous spar, pearl
spar, quartz, sulphate and carbonate of barytes, iron
pyrites, sparry iron ore, blende, calamine, &c.
Crystallized in 14-sided figures, imbedded in soft brown
marly clay like umber, which effercesces with acids;
from Kilhope mine at the head of Weardale.
Reticulated ore from Allenheads and Aldstone moor.
Steel grained ore from the Teesdale, Weardale, Allendale,
and Aldstone mines.
Specular ore or slickensides in a matrix of calcareous spar ;
from Allenheads.
Antimoniated Lead ore—From Dufton mines,
Lead Ore with excess of Sulphur.—This ore is earthy, of a bluish
grey colour, and so highly inflammable as to take fire
and bura on being held in the flame of a candle. From
Dufton mines. | i as Ss
‘Carbonate of Lead.—Massive. Colour grey. Lustre adamantine.
From Flow-edge mine Aldstone moor.
‘In 4-sided tabular crystals, bevelled on the terminal planes ;
lustre adamantine. From Allenheads and Aldstone moor.
L 2
84 Mr..N. J. WincH on the Geology of —
In aggregated acicular crystals; opake; lustre silvery. From
Allenheads and Aldstone moor.
Larger crystals of the same form: lustre adamantine. From
the Teesdale mines. .
Black acicular crystals; Fair hill, Flow-edge.
Capillary crystals; lustre silvery. On iron-stone. From
Allenheads and Teesdale.
Phosphate of Lead.—Botryoidal, of a pale dirty green colour. Grass
hill, Teesdale.
Of a siskin green colour, crystallized in small 6-sided
prisms, terminated by 6 planed acuminations, forming
clusters in light yellowish brown marly earth: from
Surside mines, Netherdale, Yorkshire. This ore yields 60
per cent. of lead, and makes a beautiful green pigment.
The following ores of lead also occur; green, yellow, and white
lead ore investing galena, from Allenheads and Aldstone moor:
coherent earthy lead ore of a dirty white colour, without lustre,
worked in considerable quantity at Grassfield mine near Nent head:
lead ore of a whitish grey colour, resembling scales of mica, the
white sill of the miners, from Allenheads, &c.: friable earthy lead
ore of a dark reddish-brown colour, from Aldstone moor, &c.
Ores of Copper.
Copper pyrites with galena from Cross gill, Aldstone moor.
Azure Copper ore.—In very small nodules imbedded in opake white
heavy spar ; found in small quantities at Wessinghope lead
| mine near Stanhope in Weardale in the great limestone.
Malachite. —Small quantities occur in the Dufton lead mine,
Northumberland and Durham. 85
Ores of Iron.
Tron Pyrites.—Massive and Crystallized.
Carbonate of Iron.—Pearlspar ; massive, mammellated, and in small
lenticular crystals, yellowish white, light and dark brown,
and black from decomposition; too common in all the
mines.
Ores of Zinc.
Blende.—Black and brown, amorphous and crystallized ; in all the
mines.
Reddish brown, in small crystals, scattered over quartz and
fluor spar, and in minute crystals upon stalactitical brown
quartz ; from Aldstone moor.
Blood-red irregular crystals on limestone, with crystals of
purple fluor ; from Aldstone moor.
Calamine is worked in old Hagg’s cross vein near Nent head. One
variety is of a yellowish grey colour; conchoidal in
fracture, and in a slight degree transparent: another is
snow white and perfectly opake.
Ore of Zinc.—In thin white opake layers or incrustations from
Allenheads.
Salts of Lime.
Carbonate of Lime, Calcareous Spar.—In acute and obtuse pyramids,
(the dog tooth and nail head spar) from Aldstone moor.
In dodecahedrons on pearl spar (Sowerby, t. 42) from Ald-
stone.
In 6-sided highly transparent prisms terminated by 6-sided
pyramids, called Tyne bottom spar; from the Tyne
bottom limestone on Aldstone moor.
In pale straw coloured 3-sided pyramids. This delicate
fossil has been observed in a vein opposite New-house
in. Weardale.
86 Mr. N. J. Wincu on the Geology of
Fibrous, of a pale pea-green colour, without the pearly
lustre of satin-spar ; from Arkendale mines.
Forming stalactites and stalagmites in all the mines: coat-
ing detached crystals of fluor from Allenheads. |
Large quantities of calcareous spar in a state of disintegra-
tion, the fragments resembling bay-salt in size and colour
may be observed on the top of Cronkley Fell.
Carbonate of Lime. Arragonite.—¥los-ferri. Beautiful specimens of
this rare mineral of a snow-white colour and satin-like
lustre have been found in Dufton mines.
Fluate of Lime.—Earthy, from Breckensyke mine, where the galena
is also found partially decomposed.
In white, topaz and wine yellow, bluish emerald green,
and most commonly in violet or purple crystals, having
the form of the cube, the cube with its angles truncated,
with its angles acuminated by 3 planes set on the lateral
planes; also in tabular and in 24-sided crystals. From
Aldstone, Allenheads, &c.
In small purple cubic crystals, bevelled on the edges,
attached to sandstone; from a mine near New house in
Weardale.
In cubic crystals of a bright emerald green colour, contain-
ing drops of water ; from the Weardale mines,
In a state of decomposition, coated by crystallized quartz
purple or blackish in colour, and sometimes appearing
as if it had been in a state of fusion; from Coal cleugh
and Aldstone mines, ib
Sulphate of Lime. Selenite.—In 6-sided prismatic crystals terminated
by convex planes (Jameson, vol. i. p. 568) on pearl-spar
in a state of disintegration ; from Aldstone mines.
Northumberland and Durham. 87
In slender detached 6-sided prisms, beautifully transparent,
often tinged in the central part with a rich orange-red
colour; from Aldstone mines. Mr. Joseph Fryer.
Salts of Barytes.
Carbonate of Barytes. Witherite.—In irregular stalactitical minute crys-
tals, opake and white ; from Aldstone mines.
In dodecahedral crystals formed of two hexahedral pyra-
mids (Sowerby, tab. 127,) of a pale wine-yellow colour ;
from Arkendale mines.
In elongated hexahedral pyramids or spiculze (Sowerby,
tab.129,) of a chalky white colour; from Arkendale mines.
Massive, of a wine yellow colour; from Arkendale.
Incrusting fragments of galena, blende, and limestone ;
’ white and opake; from Aldstone moor.
Forming crystallized balls of a dirty white colour, and
striated fracture, radiating from a center,
In irregular 6-sided prisms without pyramids, and, perfectly
transparent, occurring occasionally in the center of the
balls ahove mentioned ; from the Welhope mines in the
great limestone, where the veins in the upper silis bear
heavy spar.
Of a clove brown colour and striated texture, attached to
galena. From Dufton mincs.
Though witherite is the common matrix to lead ore in
Arkendale, it occurs only rarely further to the north.
Sulphate of Barytes. Heavy spar.—Foliated, Cawk of the miners ;
greyish white, opake ; from Aldstone moor.
In lenticular crystals (Jameson, vol. i. p. 558), cockscomb
spar; from Dukesfield and Aldstone moor.
Pe
88 Mr. N. J. Wincu on the Geology of
In small lancet-shaped crystals, opake and white, occasion-
ally aggregated into a cellular mass; from Arkendale.
In transparent tabular bevelled crystals. Those from
Dufton are very fine.
Of a milk white colour, not bevelled, set edgewise on
quartz, blende, and galena; from Aldstone.
In 4-sided transparent prismatic crystals, acuminated by
2 planes set on the lateral planes ; from a vein at Dukes-
field.
A curious mineral is found in some of the Aldstone moor veins.
It consists chiefly of indurated clay with a mixture of iron; is of a
smoke-grey colour, very hard and sonorous, and is intersected by
deep impressions of tabular crystals of heavy spar, which have in
some unknown manner been decomposed.
Earthy Minerals.
Quartz.—Is found crystallized in 6-sided pyramids in most of the
mines.
Asbestus.—Of a leek green colour, has-been observed by Mr. Bigge
in Melmerby scar, forming veins in a hard reddish brown
rock resembling basalt, but not magnetic.
I am not informed of more than six mineral springs in the district
of the lead-mine measures, and of these only two have attained any
degree of celebrity. These are the springs of Gilsland and Wardrew,
which were analyzed in 1799 by the late Dr. Garnet. The sulphu-
retted water issues from a thick bed comprising 3 distinct strata of
shale, which is covered by several measures of sandstone, forming
together a perpendicular cliff about 90 feet in height on the north
bank of the little river Irthing. Two gallons and a half of water
Northumberland and Durham, — 9
flow from the rock in a minute ; it is perfectly limpid, and on being
boiled loses the odour of sulphur.
The contents in a wine-gallon are
Muriate of soda» - ~ + 2 4 grains, sects
Sulphuretted hydrogene gas - - 17 cubic inches,’ --
Azotic gas © - = 2 2 = © 4 : » ebod ail
Carbonic acid gas ~ - = + =» 4 jods
Near the inn called the Shaws at the same place a spring of abby
beate water rises to the day, of which the ee wach to Dr.
Garnet, is as follows, :
Contents in a wine-gallon - + « pdionles 2.5 grains
: Muriate of slain = 3
Carbonic acid gas ~ = 14 cubic inches,
Azotic gage = 2 - §
On a moor a few miles distant from the same place another water
strongly impregnated with mineral ingredients is met with. It is of
a deep wine colour, and nauseous to the taste like ink ; it appears to
contain sulphate of iron and sulphate of alumina in large proportions,
Near Turret Burn, which runs into the North Tyne in the north~
western part of Northumberland, ‘a sulphuretted and a chalybeate
spring were both detected -bubbling up from under a ov moss by
Mr, Joseph Fryer,
_ At Dukesfield, towards the ‘south-west, .a inatog of ag water
holding sulphuretted hydrogene in solution has lang been known,
and another of the same description issues from the rocks in the
bed of the Tees on the north side of the river ‘about 2 miles above
Barnaud Castle. , ila
The Beds on the banks of the T weed, ,
The beds which are found on the banks of the Tweed, from
Dryburg towards the east, differ so much from the usual measures
VoL, IV, M
90 Mr. N. J. Wincu o# the Geology of
of the Lead-mine district, that I have given the account of them
under a separate section. ‘This part of the country has been ex-
plored for coal by Mr. Buddle, and it is chiefly from his pampilet
that I have derived the following information.
In the vicinity of Wark, 15 miles south-west of Tweedmouth,
the beds consist of marl, micaceous sandstone, and slate-clay ; and
about a quarter of a mile below Coldstream, in the north bank of
the river, the strata are
1. Soil, light and sandy - - - = = -feet 15
2. Ditto, gravelly - - - - - = = = 15
3. Coarse grained yellowish white micaceous
sandstone - - - - - - - - = 18
4, Micaceous sandstone alternating with slate clay to
the level of the Tweed.
These measures dip to the east at an angle of 5 or 6 degrees.
At Lenel quarry, half a mile below Coldstream on the northern
bank of the Tweed, the strata are,
1. Light soil - - - = - = = - feet 15
2. Soft sandstone and marl - - - - - 4
3. Sandstone resembling that in the last section 24
4. Slate clay.
At Bingham or Spring-Hill, north of the Tweed, the following
is the order of the strata.
1. Light sandy soil.
~ Blue marl inclining to a greenish colour.
. Blue limestone.
- Marl of slaty texture.
. Limestone.
OS Cr em OO bO
. Slate clay.
Northumberland and Durham. 91
These strata appear to alternate to a great depth; they lie nearly
horizontally, and seem to run through the whole extent of the hill.
The stratification in the west side of the hill is nearly the same as
the above, but in the upper stratum of slate-clay nodules of reddish
gypsum are intermixed, and in the lower gypsum is disposed in thin
irregular strata of amorphous fracture. | |
The nodules of gypsum contain numerous dark reddish brown
crystals of selenite. Similar nodules are also found in the hillock
on which Kelso is built, imbedded in blue shale. The marl of
Roxburghshire, when dry, is of a dirty blueish white colour, con-
taining small bivalve shells.
In Mellendean burn the strata, particularly on the eastern side,
are exposed to the depth of 60 or 70 feet, and consist of
1. Gravelly soil,
2. Marl,
3. Blue and brown slate-clay, alternating with limestone,
which contains a large proportion of sand.
Two hundred yards further up the burn, the strata in its bottom
consist of very hard bastard limestone, that is, limestone containing
a large proportion of sand. The beds lie horizontally. The upper-
most stratum in the bank near the entrance of the Dean is composed
of amygdaloid. Wacké, and amygdaloid with a basis of wacké are
not uncommon in the valley of the Tweed, where they appear to
occur between beds of sandstone, as may be seen at Sprouston
Ferry, at the Rapids about 3 miles above Kelso, and at a fall of the
river Tiviot about a mile above the same town.
The covering of Sprouston quarry is of the same kind of sandy
and gravelly soil, as generally covers the vale of the Tweed. The
sandstone rock of the quarry appears to be of limited extent, and of
an irregular oval form, being about 300 yards long and 200 yards
M 2
92 Mr..N. J. Wincu: on the Geology of
broad, and cropping out on: every side. It is of a blueish white-
colour,’ and close texture, well calculated for building, the best
part being about 20 feet thick ; but it contains in some parts nodules
of a black argillaceous earth scattered through it. It is in some parts
soft and slaty, with coaly matter interposed between the laminz..
Near the bottom of the quarry large irregular masses of very hard
calcareous sandstone occur. ‘Three veins pass through this quarry
in a north and south direction. For the particulars respecting a
vein of coal given to Mr. Buddle by the manager of the quarry, I
refer to Mr, Buddle’s pamphlet.
This sandstone seems to belong to a detached mass of rock, which
reposes on the same kind of strata as are found in Mellendean burn ;
and this opinion is confirmed by the following section of a boring
lately made in the eastern side of the quarry.
Boring in the East part of Sprouston Quarry.
Fath Ft. In. Fath. Ft. In.
Bad freestone : oe Qe Brought up 10 2 —
Dent . : . — 4 —|/Strong black dent ‘ »- Loe
Whin | d 3 - — 1 —|| Hardstone : _—- 4—
Blue dent 3 4 A 3 —1|| Blue freestone : Ae Thee)
Hard limestone : - —-1-—|Hard whia- . Z _ — 3—
Strong brown clay — 4 —| Black dent — 5—
Blue dent . : - Ll 3 —}| Whin and dent altérhating cee 2
Very hard whin : - — 1 6] strata about 3 or 4 inches thick teu
Brown dent : - 1 — —/! Hard freestone » 2i—
Hard whin — 3 —||Stone extraordinarily, hard 9.) ar cons
Freestone — 2 —|Left off in very hard brown
Clay mixed withrdark blue dent — 4. — stone, and’ from its weit} A —
Blue dent — 5 6]| supposed to contain ironstone
Blue freestone 4
Strong blue dent eee with wibeeos ee
“iron ore Fathoms 21°— —
Carried up 10" 2 —
. The quarry of Stodridge situated in the Roxburgh estate of Fleurs, ,
is very. similar to. that of Sprouston. ,
_ In. the vicinity of Ford castle; near the fort of the Flodden hills,
pycsteites of grey or greyish white arenaceous limestone bassets out.
Northumberland and Durham, 93
This rock is very much like a fine-grained sandstone, and contains
so large a portion of silex and clay as to be scarcely worth burning
for manure. It would be called a bastard limestone. This bed
appears to be one of the lowest in the series to which the metal-
liferous limestones belong; it occurs in the north-western part of
the district, and is not uncommon in Roxburghshire, lying very
near the red sandstone.
Porphyritic Formations of the Cheviot Hills.
A considerable tract of the north-west of Northumberland is oc-
cupied by the Cheviot hills, which rising from below the stratified
country of the Lead-mine measures, stretch westward into Roxburgh-
shire. The higher parts of these mountains being covered with
peat moss, and their lower acclivities with alluvial soil, it is not easy
to trace the exact line of separation between the porphyritic rocks,
of which they consist, and the Lead-mine measures. It has been
seen however that to the north the porphyritic rocks do not descend
to the banks of the Tweed ; to the south-west, limestone is quarried
on the sides of Carter Fell, and a small colliery is worked at
Kedderburn in the same neighbourhood. Towards the south, por-
phyry is seen on the banks of the Coquet at Linn-bridge, a mile and
a half south of which, on the hill at Woolcoats, several coal pits are
worked. For the other boundaries of this range I must refer to the
map. , | )
Cheviot, which gives its name to the whole group, is a huge
round topped mountain, rising 2642 * feet above the level of the
* Leslie’s Elements of Geometry, 2d edit.
94 Mr. N. J. Wincu on the Geology of
sea. It is situated in 55° 32’ N. latitude, and is distant from the
coast at Beadnel 19 miles. It commands a noble prospect over
the surrounding country, and presents a conspicuous sea-mark to
vessels coming across the German ocean. Hedgehope and Harthope
are subordinate mountains, and the Flodden Hills on the north-
eastern side are a still lower group. ‘The latter descend gradually
to Millfield plain, where the primary formation terminates in that
direction.
At the foot of the ridge, in some places the usual attendants of
primary mountains, the red sandstone and the greywacke slate,
are found rising to the day. The former, which bassets out in
Roddam Dean, approaches to a conglomerate ; the latter, which
appears on both sides of Markington burn, is fine grained in struc-
ture ; but the slates there quarried do not stand the action of the air,
The blocks of stone on the summit of Cheviot consist of flesh-
coloured felspar porphyry enclosing crystals of reddish white felspar
and occasionally minute crystals of hornblende, resembling in this
respect the porphyry of Inverary mentioned by Dr. Garnet and St.
Fond. Among the rude masses and blocks which lie scattered by
the sides of the Wooler-water, porphyry slate, claystone porphyry,
porphyritic syenite, granitic syenite, basalt, and coarse red jasper
may be recognised, and the Coquet, Aln, Bremish, and Glen
abound with agates.
One of the beds which produce the latter mineral is a reddish
brown amygdaloid with a basis of wacké, the geodes of which are
coated, as usual, with green earth. This rock may be observed in
situ on the banks of the Coquet a little above Linn-bridge.
Hornblende rock is by no means uncommon among these hills,
Housy crag, which rises above the farm house near Langley ford,
in the valley between Hedgehope and Cheviot, is composed of a
Northumberland and Durham. 95
coarse grained variety of this rock, closely allied to the porphyry,
and the perpendicular cliffs of Hellhole on the opposite side of the
Cheviot consist also of the same rock.
_ The only metallic ores known to exist in this district are, bog
iron-ore, which is found in the bottoms of morasses, and red ochre
with nodules of hematite from a small vein traversing the rocks
above Langley-ford. The shepherds use the latter for marking
their sheep.
Alluvial matter found on the surface of the preceding formations.
Blocks or detached masses of different rocks are found scattered
over the surface of all the preceding formations and imbedded in
the soil.
Masses of blue coralloid limestone, the produce of the lead-mine
district, are found at the surface at Cullercoats above the magnesian
limestone. Similar blocks are found dispersed over the other for-
mations.
Masses of close-grained sandstone occur every where in like
manner.
Masses of hard black basalt are found every where in abundance.
From this stone the ancient inhabitants of Britain formed the heads
of their battle-axes, which the people call Celts. They resemble in
shape the tomahawks brought from the South Sea islands. Barbed
arrow heads, neatly finished, and made of pale-coloured flint, are
frequently picked up on the moors, and are called elf-bolts.
Masses of porphyry, resembling that of Cheviot, and of the Cum-
berland mountains, and of green basaltic porphyry are common.
The base of the latter is of a greenish black colour, and contains
96 Mr. N. J. Wincu on the Geology of
large crystals of greenish white felspar. Blocks of it are found in
the bed of the Deals water at Dilston near to Hexham,
Blocks of porphyry slate are found on the banks of the Tyne near
to Horsley, and masses of the same rock, including small red garnets,
in the bed of the Deals water.
Masses of fine-grained granite appear on the surface over the
whole country. Those from the banks of the Tees and other parts
of the south of Durham consist of small grains of white quartz,
black mica, and flesh-coloured felspar.
Considerable quantities of marl have been discovered on the
west side of the river Till in situations which seem to have been the
bottoms of lakes; and in this alluvial matter horns of some species
of bos and cervus are found imbedded. ‘The marl is of a light grey
colour, and contains bivalve and univalve shells which retain their
pearly lustre. This substance has been noticed at Wark, Sunnylaws,
Learmouth, Mindrum, the Hagg, the Hopper, and at several other
places in that neighbourhood. It probably rests in some places on
the beds that I have described as prevailing on the banks of the
Tweed, and at others on porphyry or grey-wacke. |
eee
Phe following passage should have appeared in the paper after the account of
the Walker dyke at page 22.] ,
The next basaltic dyke worthy of notice is one which, passing’
from west to east under Tynemouth Priory may be seen to divide
the strata at the south-east point of Prior’s haven, where it farms @
wall 12 feet broad in the cliff and in the ‘rocks below. A vein or
fissure 12 inches in breadth and filled with tufaceous matter inter-
sects the dyke from top to-bottom near its center, and the basalt
strongly resembles the Coley Hill stone. ;
Northumberland and Durham. 97
APPENDIX, No. 1.
Sections of the Strata at Dinsdale, situated on the North Bank of the
Tees, 35 miles east-north-east of Croft Bridge.
No. L.
Fath. Ft. Iv
Clay : : : 4 1 6
Blue stone-clay ‘with whin tumblers : A _ —- &—
Blue sand - - : — 2 6
Blue stone-clay A - — 5 6
Foul Coal ° , —— 6
Brown sand, ; : ‘ - Si 2 8
Foul Coal : . : —— 5
Blue sand with water : —— 4
Stone-clay with large whin tumblers ‘ . ° 3—- —
Red stone : x ; : —- 2—
Fathoms 10 — —
No. 2.
Near the Fishery, 180 yards from the Garden House.
Fath, Ft. In.
This aceount begins at » 56 1 —
Red stone and white post, and post girdles with water . 1 5—
Red metal stone with blue and white scars HE
Redish post, and scars of hlue and white leek chalk of 35 6
‘alabaster ° . . :
*Chalk of alabaster - : 2 . — &—
Strong white post of a limestone nature ‘ a ty dy f
Fathoms 65 5 7
No. 3.
Fath. Ft. In.
Soil and clay - : : 2— 6
Darkish stone-clay with whin tumblers : 3, .2..9
Red metal stone with grey post girdles : A 8— —
Red stone and white chalk lumps : . 2— —
Fathoms #5 3 3
* Gypsum.
VoL. Iv. u
98 Mr. N. J. Wincu on the Geology of
No. 4.
Soil and brown sandy clay . F
Gravel and sand
Stony clay
Brown sand and scars of Coal
Leafy clay and sand
Blue stony clay and beds of sand
Brown sand
Coal and scars of sand
Brown sand with scars of Cis
Darkish heavy clay
Darkish stone clay and sand with scars of Coal’
Red sandstone with white scars
—_——
No. 5.
Fathoms
Fath. Ft. In.
— 3 6
— 1 4
1 5—
Ley 9
TY a ee
2) 4 BS
13—
— 1 9
— 1 6
2306
3°49
Sana!
146 2—
Section at Woodhead near Tees side.
Soil and brown clay ;
Darkish stony clay with whin tumblers
Red metal stone with grey girdles
Red stone with white girdles
White and grey stone
*Chalk with white flinty lumps
Blue whin with water like the Harrowgate ag 19 2 6
Strong white post with whin girdles
Bastard whin i
Strong white post with whin girdles
Blue grey metal stone with white scars
*Chalk (called in another x Ponee whe
Soft red stone :
Red and white post
White post with red scars
Red, white and grey post, with at) ‘of red metal
Soft blue grey metal
Grey and white post -
Strong blue-grey stone .
Strong white and grey stone
Whin . >
Mixture whin
Strong white post, supposed to be ofa limestone ie
and whin girdles
Here the undertaking | was abandoned.
* Probably Gypsum, which is found in the same bed at Newark, anil other places in Nottinghamshire
and Derbyshire.
Fathoms
Fath. Ft. In.
epee
Soe ay oh)
Sao eee
dF bel Binal vce)
fo Ae
1 i1—
— 1 6
1— 6
giz tyalt
6 — 6
1 2—
— 2 6
pp tg
3° 1—
PEE fe
4 3—
Re ree et
5 3—
ey ee
10 — —
ust [ig alee
1 3—
US. tae
14,31 4
Northumberland and Durham.
APPENDIX, No. 2.
Vend of Coals from the Port of Newcastle.
Shipped of Newcastle Chaldrons
Year
Coastways
Ueaee alk © ur ataselste
d bela 351,890
1776 TTR te a 380,000
1791 404,367 45,702 | 450,069
1792 | 456,106 42,993 | 499,099
1793 | 465,549 34,105 | 499,654
1794 | 387,460 40,461 427,921
1795 | 463,496 40,342 | 503,838
1796 | 438,777 42,778 | 471,555
1797 | 459,166 38,149 | 497,315
1798 | 394,369 44,722 | 439,091
1799 | 447,819 43,366 | 491,185
1800 | 537,793 47,487 | 585,280
1801 452,192 50,401 502,593
1802 | 490,488 44,001 538,489
1803 | 505,137 44,324 | 549,461
1804 579,929 52,589 | 632,518
1805 552,827 49,573 | 602,400
1806 587,719 46,107 | 638,826
1807 534,371 27,342 561,713
1808 | 613,786 15,661 629,447
1809 | 550,221 14,632 564,853
1810 | 622,573 19,261 641,834
1811 634,371 18,054. | 652,325
1812 | 638,158 24,994 | 663,151
1813 | 584,011 14,762 | 598,773
Vend of Coals from the Port of Sunderland.
Shipped of Newcastle Chaldrons
Total
Year Oversea
Coastways
54,150 | 300,858
246,708
256,889 53,313 | 310,102
255,011 50,064 | 305,075
243,939 38,885 | 282,824
282,946 5,884 | 288,830
249,246 6,293 | 256,538
279,581 6,434 | 285,016
274,132
298,570
296,552
291,317
5,111 | 279,344
4,039 | 302,609
100 Mr. N. J. Wine on the Geology of
Vend of Coals from Hartley and Blyth Collieries.
Shipped of Newcastle Chaldrons
Year Coastways | Oversea
39,619
38,400
38,550
37,652
Coals imported into London.
Of London Chaldrons
Coastways
From 1776 to 1779 on
an average yearly . 658,643
1801 862,088
1802 902,224
1803 940,470
1804 947,001
1805 971,270
1806 987,750
1807 933,148
1808 1,088,050
1809 923,440
1810 1,120,237
1811 1,115,171
1812 1,071,361
1813 970,901
50,000 Chaldrons a year by the Canal.
Northumberland and Durham. 101
APPENDIX, No. 3.
Estimate for boring to the depth of one hundred fathoms in the
counties of Roxburgh or Berwick, under the usual risks attendant on
such operations ; by Mr. Buddle in 1807.
Shillings #£ s.
Boring § fathomae vin so) ccaisae sen dne? Be Oy ai, steyere) ita 1, 10
DF OI stains +o kt ACBL. Me V2) he tekelsie «16)-)© 3 —
EM 1 ae RL Ae eg Pm, TSP er etateley« fol aor 4 10
© OO Sais gitioin'e S « winie.c'a'o do) ott ule Pee er oe 6 —
5 Gittings monies Riladayoiee Sepyqrerg is SOpy Dadieyeyss ae! « 7 10
i a ee Ae ee ee eae SO) aigietsfat oais,0 9 —
Bdmttaiay GN tit deeva ss © SE a BA Odo 10 10
F GHG) is ca: of idee ad pea BE ataa: & ais MBO O Oe «ee 12 —
ie A RE ey aR Abate ie i a OE 6 thiajae she's 13 10
Ut LR Os ene ean 10 WA Sooo hoe 1 —
CE ens ot airy ar er a ack 5 1D) sen roeooid te 16. 10
piditte, JP GAS! PAA dds Lies es So NOOO 18 —
i a ce ONY eS Pa aA oS ZING an Oe A 19 10
MG eee ots aelavets che atgiacac eke =» SA oles) stance ore 21 —
BGO. TA Dok ct maienrs om plo brs, *t eee 22 10
BHO: ioe Werhends oak. orate beara « iN} WEE Ginlodine Oo 24 —
Sditto .'. . . hatter fe Od eisiew la eens MOINS Ailo Heian 25 10
UNC SS 8 Trae ee wu bictacee ves UO Sear terers alert ots 27 = —
BAOVGII S.No SAIL, AB 23 UWA 20) 5 Pient SBIIIO
DOOR aos arcs loons fw aie. ence ee o-2) 0.6 WO) Gonaine SO GE 30 —
100 315 —
Carriage of the rods, tagle legs and gin blocks, rope and 100
other apparatus, and fitting the same .............-. Te
Sharpening the geer, finding grease, coals, a horse to draw 200
the rods, and sundry other charges during the boring .. : i
ACcidents IRLWOFIN Seek. oa \c. 2a sieyys s,s ACh Sire ROSS SAED 345 —
Extra expence in boring through Whin ................. 140 —
£1100 —
Estimates for boring to such great depths cannot in general be
offered as accurate, from the stone to be perforated being in some
cases so hard as hardly to be bored through at all, and from the
great risk of breaking and losing the rods in the hole during the
boring.
Il. On aWhin Dyke traversing Limestone in the County of
Northumberland,
By the Hon. HENRY GREY BENNET, me. r.r.s.
VICE-PRESIDENT OF THE GEOLOGICAL SOCIETY.
[ Read 6th March, 1812. ]
L BEG leave to communicate to the Geological Society some par-
ticulars of a whin dyke, which traverses a portion of the limestone
strata in the northern district of the county of Northumberland, and
projects into the sea on its north-eastern coast.
It is seen most distinctly at Beadnel Bay, and may be traced a
few miles inland from this spot, where it forms a species of pier into
the sea. ‘The surface strata have been washed away, and the dyke
itself is left some few feet higher than the rock on each side of it.
Upwards of 300 yards are thus seen at low water running in a right
line from the sea towards the north-west, 27 feet in width. It rises
in a perpendicular position through all the strata, without making
the least alteration in the dip or inclination of those that are adja-
cent: but some short distance from the place where it is laid open
to view, the limestone strata are much broken and dislocated. The
qualities of the different strata in contact with the dyke differ mate-
rially from those of the same strata at some distance from it, parti-
cularly the limestone, which when lying in the immediate vicinity
of the whin will not burn into lime of any value. This deteriora-
The Hon, H. G. BENNET on a Whin Dyke. 103
tion diminishes in degree as the distance from the dyke increases,
and it is about 20 feet before the limestone acquires its perfect pro-
perties of burning into good lime. The same thing is observed in
both the strata of limestone. The stratum of what I shall term a
species of tuf, composed of felspar and carbonate of lime, is indu-
rated as it approaches near to the whin, and it then resembles in
structure and colour the whin itself; it is much fuller of joints near
the dyke, than at a distance from it. In no case did there appear to
be a complete junction of the whin with the limestone, or with
the tuf; but there is invariably a small fissure, that seems to sepa-
rate them to a great depth, on the edges of which the limestone
sometimes assumes a sparry structure, and is in some places con-
siderably mixed with pyrites. In one part of the dyke a piece of
the tuf is enveloped in the middle of the whin; this fragment is
about 60 feet in length, and 2 feet in breadth at its broadest part,
and the two ends terminate in points.
The following is a section of. the strata, obtained from the infor-
mation of the proprietor of the lime works. FEET.
Boe ee a ge heh st ne Mero ee ee
ec eee gee eee bus, she Mea Te. et oe)
Black metal, argillaceous slate. . . . . . 27
MeeB es es 5 Peete tet ek one | EO
Slaty and micaceous sandstone and black metal 27
Coal, a thin seam.
That part of the strata, which the workmen called argillaceous,
I had not an opportunity of examining, at least where it was in
contact with the whin, it being under water. Neither could the
coal be seen, as it is at too great a depth.
The strata dip about one yard in six to the south; but their ge-
neral inclination in this district is to the east and north-east.
104 The Hon. H. G. BENNET on a Whin Dyke.
The specimens that accompany this paper will shew to the com-
mon observer the difference between the limestone when in contact
with, or at a distance from the dyke, as well as that between the
dyke itself and the ordinary whin rocks of the county, such as those
which are found on the Cheviot, and which form large masses on
that range. Indeed all the whin dykes that I have seen in the
northern district of Northumberland, the two which are so near to
each other in Holy Island, and those which form the Fairn Islands,
no less than that at Beadnel, bear a striking and uniform resemblance
to each other ; and are unlike those ranges of whin which are com-
- posed principally of hornblende, and which prevail to such an extent
m the north-western parts of the county.
UI. Description of an Insulated Group of Rocks of Slate and Greenstone
in Cumberland and Westmoreland, on the east side of Appleby,
between Melmerby and Murton.
By rHe Rev. W. BUCKLAND,
PROFESSOR OF MINERALOGY IN THE UNIVERSITY OF OXFORD, AND
MEMBER OF THE GEOLOGICAL SOCIETY.
Read March 28th, 1815.
Few rocks m this country present in a small compass a structure
more complicated and difficult to be understood than those which
occupy a small district in Cumberland and Westmoreland, on the
east side of Appleby, between the villages of Melmerby and Murton,
which I visited in September, 1814, accompanied by my friend
G. B. Greenough, Esq.
The town of Appleby is situated about 12 miles from the upper
extremity of the great plain through which the rivers Eden and
Petteril have their course, and which continues across Solway Frith
into Scotland, increasing considerably in breadth on the north of
Carlisle.
The stratum composing the greater part of this Plain is a red
sandstone affording gypsum in many places. Its breadth near
Carlisle from east to west is about 15 miles, but it becomes gradually
contracted as it approaches the south till it terminates near Brough
and Kirkby Stephen, being encircled by hills more elevated and of
higher antiquity.
VOL. Iv. )
106 The Rev. W. BucKLAND on a Group of Rocks
The west and south-west boundary of this plain are the slaty
mountains of Cumberland winding from Ravenstone dale to near
Hesket, Newmarket, Ireby and Cockermouth; a belt of entrochal
or mountain limestone covered by a concentric belt of coal measures
separates the red sandstone from the slaty rocks just mentioned.
The same plain is bounded on the east by an almost precipitous
escarpment, extending north and south from near Brough by Dufton
Fell and Cross Fell to Croglin, Castle Carrick, and the hills south-east
of Brampton. The elevation of great part of this escarpment is
considerable, varying from 1000 to 2000 feet ; Cross Fell, its highest
point, is 2901 feet. It displays the outcrop, and is chiefly composed
of the lower members of the great: series of strata described by Mr.
Winch as occurring between Newcastle and the base of Cross Fell.
The regular structure of the plain of sandstone at-the base of this
escarpment is interrupted near Appleby by projecting masses of
slate and greenstone, attended by some: broken strata of lime and
coal measures, which it will be the object of this paper to describe.
These rocks (as may be seen by reference to the annexed map)*
form an insulated group extending nearly north and south along
the base of the escarpment of the great limestone series of Cross
Fell, and of which the lowest stratum is stated by Mr. Winch to
be incumbent on the old red sandstone (Geol. Trans. vol. iv.)
This old red sandstone, which it is of the highest importance to
distinguish from that more recent red sandstone which forms the
plain of Appleby and Carlisle, appears here in its common form
of a coarse puddingstone, and may be traced along the scar in the
place thus assigned to it from Melmerby to a spot called Highcup
near Murton.
Coextensive with this conglomerate is a subjacent mass of slate
which forms a kind of broken under-terrace at the base of the great
* Plate 5.
in Cumberland and Westmoreland. 107
escarpment from Melmerby scar on the north to Murton Pike on
the south. This narrow line of slate is bordered on its west side
by an irregular but nearly parallel range of greenstone. The
breadth of both these rocks together seldom exceeds a mile, and
towards their north extremity is contracted to the compass of a few
yards ; here they appear also much disturbed and confusedly mixed
together; the spot is marked in the map as Melmerby Lane End,
about one mile south-east of the village of that name. They assume
greater strength in their progress towards the south, and the position
of the greenstone becomes more decided on the west of the narrow
line of slate.* The variety of proportions in which its ingredients
are found combined is quite endless ; every hill, almost every block,
gives a new character of it.
These rocks of slate and greenstone form two parallel narrow
ranges, displaying on the surface an irregular outline, and attracting
attention by the striking feature of three lofty conical pikes, distin-
guished by the names of Knock pike, Dufton pike, and Murton
pike.f Of these the former, which is the most northerly, is chiefly
composed of greenstone. Dufton pike, the central one, contains
both greenstone and slate; and Murton pike, which is the most
elevated, and at the south extremity, appears to be composed almost
entirely of slate.
We found no greenstone indeed within a mile of Murton pike, it
seemed to terminate at Keisley about one mile south-east of Dufton,
a spot which I shall again notice as affording a singular mass of
limestone.
Though the exact limits of these two ranges might possibly be
ascertained by careful and patient investigation, their line of junction
* See Map and Scction, plate 5. + See Map, plate 5:
o 2
108 «| The Rev. W, BuckLAND ox a Group of Rocks
is not distinctly marked; the eye cannot trace it in the outline of
the hills, nor is it laid open in many places by sections of the water
courses.
Their order of superposition (if there be any) is equally inde-
terminate ; sometimes they abut abruptly against each other, some-
times the slate is uppermost, at others, indeed most frequently, the
greenstone.
Imperfect roofing slate has been dug at each extremity of this
range, on the south at Langdon moor near Murton pike, and on
the north at Middle Rig near the head of Melmerby Beck.
Slate pencils also may be obtained from many parts of the slate
rock. Places named to us were * Knock Fell on the east of Knock
pike; Plasker ; Ashlake Pike, half a mile north of Ardale water; Gale
intack, Melmerby Lane End, also a field half a mile south of Murton
in the valley towards Brough, and Rickargill Beck 4 miles north of
Melmerby under the continuation of the escarpment northwards.
I mention this last place because (if the information was correct
which we received on this point from two competent witnesses)
the existence of these pencils shews the presence of the slate rock
four miles north of the spot where it seemed to end near Melmerby.
We did not examine this line ourselves, but could hear no tidings
of slate or greenstone at any place north of Melmerby, excepting
Rickargill, and we know from observation that they do not exist
a little further to the north at Croglin, or between Croglin and
Castle Carrock. :
At Swinedale Beck, between the south base of Knock pike and
Dufton Fell, the slate contains one or two thin beds of blackish
transition limestone, which are laid open in the water course at Cater-
* The places printed in Italics are not mentioned in the map.
in Cumberland and Westmoreland. 109
pallet, a hillock one quarter of a mile east of Gale Hall, and between
one and two miles south-east of Melmerby. ‘The slate is cut by a
broad dyke, of which the direction is nearly east and west, and its
breadth about 25 feet. ‘The substance of this dyke is composed of
reddish compact felspar mixed with talc, and the latter becomes
more bright and distinctly visible where the rock has undergone
decomposition.
Under the south base of Knock pike close to the Swinedale Beck
is a small portion of rock composed chiefly of dark mica, occasion-
ally interspersed with small crystals of felspar, disseminated uniformly
through the mica. On this lies a mass of highly compact whitish
-felspar and coarse greenstone.
On the summit of this Pike, which is nearly conical, and steep on
all sides, is an outlying hummock of coarse grained sandstone,
agreeing in substance with one of the lowest strata in the neigh-
bouring escarpment, and more recent than the old conglomerate.
Whether this latter rock, or any traces of slate, are interposed
between the summit of the pike and greenstone of its base, we had
no opportunity to ascertain. I have specimens of the grit taken
from the summit.
At the west root of Dufton pike, in a field called Banky Close,
and surrounded on all sides by greenstone, is a species of granite
that is extracted to build field walls. It consists of bright salmon
coloured felspar, in which are disseminated at very irregular inter-
vals plates of bright silver coloured mica, varying in diameter from
an inch to a line, and interspersed with a few small specks of quartz.
This granite was so covered as to be visible only at a small ridge
where the quarry was wrought. It might either be the projecting
crest of a subjacent fundamental mass, or it may be a dyke cutting
through the greenstone. In the quarry it is 15. yards broad, and
110 The Rev. W. BuckLanp on a Group of Rocks
seems to run east and west. It is found also two fields below in a
westerly direction.*
About a mile south of Dufton pike, in the direction of Keisley,
in a streamlet that joins the Keisley Beck, and runs down to the
village of Dufton, in a field or farm called Hindrigs are other traces
of granite exactly like that of the hills on the south-west of Shap,
containing large flesh coloured crystals of felspar ; it appears to be
in its natural position, and (like the neighbouring granite of Banky
Close under Dufton pike) either a dyke or the projecting back of a
substratum of this substance.
The part I saw uncovered was about 10 feet square, and had no
appearance of being a rolled block. The watercourse, 10 yards off,
passed over a small portion of the same granite in a little cascade;
but here also it was so covered with grass that absolute demonstra-
tion could not be obtained. Iam inclined however to think, that
this granite is the point of a subjacent rock, and a new locality of
that variety which is so different from all other English granites,
and so strongly characterised at Shap Fell.
In the field adjoining the Hindrigs granite immediately above
and on both sides of the water course were large blocks composed
entirely of dark mica, which lay half buried in the soil, and appeared
* This granite much resembles that of a dyke which at a place called Demming or Red
Crag at the highest point of the road about half way between Shap and Kendal, and near
the mass of the granite of Shap and Birbeck Fells, is clean extracted from a long narrow
quarry by the road side, so as to prove decidedly that it is a dyke about 30 feet in breadth,
aud lying between two side walls of course slate.
We were told that this dyke runs off nearly north and south, a mile or two south-south-
east, and nearly a mile north-north-west of the spot where we saw it by the road side.
Its south-south-east portion keeps nearly along the crest of the hills of grauwacke and
grauwacke sate that run south-east from Birbeck Fells to Tebay on the Lune near Orton,
in their course towards Sedburgh and Inglcton.
in Cumberland and Westmoreland. i 13
to have been derived from a subjacent rock of mica connected with
the granite.
Prat sk Be» En Th eales
Having described as far as I know the extent of the slate and
greenstone, with the subordinate rocks and dykes that accompany
them, I will now consider the strata by which they are encircled,
and which on the east side ate widely different from those on the
west.
On the east side beneath the outcrop of the great limestone series
of Cross Fell, (of which Mr. Winch gives the thickness at 450
fathoms,) the old red sandstone, in the form of a conglomerate, is
regularly interposed between the lowest stratum of the above
series and the slate, with no appearanee of any great derangement.
But on the west side of the line of greenstone there are evidences
of disturbance, on a scale of considerable magnitude.
There is not a trace of those beds that are so regular on the east
side, and appear there in such enormous thickness, and except in a
few spots which will immediately be described, the red sandstone
of the plain of Carlisle abuts abruptly against the greenstone and
slate,* as it does also against the truncated extremities of the lower
strata of the great limestone series+ along the base of their
escarpment on the north of Melmerby towards Brampton, and on
the south of Murton towards Brough, beyond the north and south
terminations of the slate and greenstone that have been described.
The village of Melmerby stands upon this red sandstone ; a small
stream that runs down to it (called Melmerby Beck), from the base
of the great escarpment of the scar, has its course for three quarters
of a mile above the village in the red sandstone, which here also
* See Section No. 1, Plate 5, letters A. B.C. + Ibid. letters C..D. E..
112 The Rev. W. BuckLaANnp on a Group of Rocks
contains gypsum as in numerous other places on the banks of the
Eden and the Petteril, and in the great valley of Carlisle.
At the distance above mentioned the sandstone abruptly ceases,
the water course (a ravine about 30 feet in depth) which till now
had traversed the red sandstone in a direction east and west, sud-
denly turns at a right angle to the south, and continues its bear-
ing exactly along the line of junction, having its east and west
banks composed of materials very different.
At the point where the water course turns suddenly to the south
the sandstone abuts abruptly against a dark compact greenstone, red
externally, and very ferruginous.
This last rock with its varieties forms the east, and the sandstone
the west cheek of the ravine for a quarter of a mile up the stream
southwards, the excavation being so exactly along the line of junction
that no contact or order of superposition can be distinguished.
Here, at about a mile above the village along the Beck (the name
of the spot is Melmerby Lane End,) the greenstone on the east bank
becomes mixed confusedly with considerable masses of slate, and
the channel ceases to have the red sandstone on its west flank, which
becomes occupied by shattered fragments of limestone and coal
measures.
These last beds extend from henee in a line nearly parallel to
the slate and greenstone ranges, being interposed between them and
the red sandstone of the plain for nearly three miles south from Mel-
merby Lane End towards Kirkland,* but are so dislocated and con-
fused that the coal seams (which are very thin, often less than a
foot,) are in many places quite vertical, and extracted by sinking
perpendicularly downwards as in a well; but they occur no where
* See Section, Plate 5, No. 2, letter A.
in Cumberland and Westmoreland. T 113
in great quantity, as from the shattered condition of the strata, the
coal is soon lost, without a clue to lead to its recovery. It has no
regular roof or floor, but is rather inclosed by broken side-walls,
and sometimes is found lodged in henipeed nests and sein it is
now seldom wrought.* . .
The edges of these highly sétihed and btoken stratd may be
traced by a very low scar,} or kind of escarpment slightly risin'g
towards the east and running parallel to, and alorig the base of the
greenstone hills from Melmerby towards Kirkland.) . es
The limestone accompanying these coal measures is but in: thin
beds, and equally dislocated and shattered, so that no order of super-
position can distinctly be made out.. I saw it at. one place nearly
vertical, its dip being to the west; it. was on the north side of. the
Ardale water, as marked in the map; it lay between two beds: of
sandstone that had the appearance of coal grits,. and :within a few
yards of the slate and greenstone which aré here confusedly mixed
together. - The lowest grit bed touched the slate.
‘Vertical coal measures are seen touching the greenstone ata
section in Ousby Beck at the corner of the highest inclosures: in
ascending the stream from the village of Ousby. Fi
‘The following are localities where coal has been dug within the
limits above mentioned.
_.Melmerby Lane Head, Hag Gate, Gale Hall, and Ousby Towa
ied; &e
hagmesiona 1s ug near Hag oS Gale Hall, and Ardalé water, bee:
= Strailar-¢ cases *i ‘bells of Coal hecoming vertical by dislocation will be recognized | in
the “perpendicular bed ‘of coal described by Mr. Bakewell at Bradford near Manchester,
¢Géol. Trans, vol. ii, p. 283,) and iin the Mendip colliertes;near Mells, where a bed of
coal is said to be, bent backwards to the shape of the letter Z. .1 have this fact on good
authority but have ‘not seen it. sald
+ See Section, Plate 5, No. 2, letter A.
VOL. IV, P
114 The Rev. W. Buckianp ow a Group of Rocks
‘These limestone and coal measures occupy no great breadth, and run
north and south in a line nearly parallel to the ranges of greenstone
and slate, being generally in contact with the former of these sub-
stances. Their extent longitudinally is from Melmerby Lane End
to the Ardale water. From the latter stream southwards to the
village of Murton, the red sandstone abuts for the most part against
the greenstone. One exception occurs at Keisley about one mile
south-east of Dufton, in the direction of Murton pike, where there
is an insulated mass of stratified entrochal limestone several fathoms
in thickness, and occupying superficially a little more than an acre
of ground. It is inclined to the west at an angle of about 80°, and
covers like a shield the abrupt end of a hill of greenstone, known
by the name of Keisley pike, but insignificant in comparison with
the three great pikes before described.
This limestone seems to bear the same relation to the greenstone
as did the shattered coal measures and limestone before mentioned
near Melmerby. It dips so rapidly that it disappears immediately
at the base of the hill towards Appleby, and is at once lost under
the red sandstone.*
We did not examine the base of the continuation of the great
escarpment from Murton pike southwards towards Brough, but
the concurrent testimony of many experienced miners leaves no
doubt that the slate terminates a little south of Murton pike, and
the red sandstone of the plain closes up against the escarpment from
thence to the town of Brough.
It was stated at the beginning of this paper, that it is of the
highest importance to distinguish this more recent sandstone of the
plain of Carlisle from the old red sandstone or conglomerate that
divides the great limestone series of Cross Fell from the slate.
* See Section, Plate.5, No. 3.
in Cumberland and Westmoreland. 115
It is important because it has been stated by Mr. Forster (in’ his
section from Newcastle to Cross Fell) that this red sandstone of the
plain is the lowest stratum of the above series, and because. its
position at the base of the escarpment, both on the north of Mel-
merby towards Brampton, and on the south of Murton towards
Brough, would without careful investigation lead to such a con-
clusion.
But the section that has been described from Melmerby to Dufton
proves that the old conglomerate is the only rock that exists there
between the limestone series and the slate, and our examination of
the base of the escarpment north of Melmerby from Croglin to Castle
Carrick pointed out the source of this error, which is so common
that we could not find an individual who did not believe in it;
though not one had ever seen a section that proved the fact.
The source of this natural and almost necessary error, is the
low position of the red sandstone at the base of the immense
escarpment,” where it abuts so bluff against the abrupt and truncated
extremities of the lower strata of the great limestone series, is in
such absolute contact with them, and so accommodated to their
irregularities, which it fills up, and seems as it were to notch into
them, that it would be almost impossible to avoid the error which
is so popular, without looking to the general history of this stratum,
and to the sections which display junctions at the edges of the plain
of Carlisle, in which this new red sandstone forms the upper and
most extensive deposition.
One of these sections has been given near Melmerby: another
may be seen in the cliffs between Whitehaven and St. Bees Head.t
These are lofty, and present a distinct perpendicular section, in
which it is seen at the point of the junction nearly two miles south-
* See Section, Plate 5, No. 1, C. D. E. t Plate 5, No. 4.
P 2.
118 Ona Group of Rocks i Cumberland and Westmoreland.
west of Whitchaven that: the upper beds of the coal measures lie
under a stratum of magnesian limestone. On the limestone is
immediately superimposed the immense deposit of red sandstone
that forms the entire thickness of the cliff from this point to St.
Bees Head. .
The dip of the coal measures and magnesian limestone is nearly
south-west towards St. Bees, which brings them under the red
sandstone at the point of junction above described, where there is
also a large gypsum quarry in the lowest part of the red sandstone.
It would not be within the object of the present paper, (which
is to describe the district between Melmerby and Murton pike,)
to enter into the detail of these sections or the general history of
this stratum. ‘These however lead to a conclusion almost inevit-
able, that the Carlisle red sandstone is the same with that of the
vales of Cheshire, of Salop, Lancashire and York ; the matrix of our
great quarries of gypsum and rock salt; and a deposition more '
recent than that magnesian lime which is incumbent on the upper
strata of the principal English Coal-fields.
¢
IV. Observations on the Mountain Cruachan in Argyleshire,
with some Remarks on the surrounding Country.
By J. Mac Curtocu, M.D. F.L.S. President of the Geological Society,
Chemist to the Ordnance, Lecturer on Chemistry at the Royal
Military Academy, and Geologist to the Trigonometrical Survey.
[Read 2d December, 1814. ]
Tue geological history of this mountain being, as far as I know,
unrecorded, I shall relate the few observations which I made on it,
as they are sufficiently numerous to form at least a basis for future
and more accurate investigation. |
It is evident to any eye in i through the vales of |
Glenorchy or Glenara to the head of Loch Awe, that the nature of
the country has changed. The rugged forms and rocky faces cha-
racterizing those hills of mica slate which bound Loch Lomond,
Loch Long, Loch Fyne, or Strath Fillan, have disappeared; the
mountains assume a more uniform flowing line, their sides are more
completely covered with herbage, and exhibit fewer denuded rocks ;
their summits are less serrated, and are almost the only parts which
exhibit the naked rock, while at the same time they are strewed with
heaps of fragments, a character from which the hills of mica slate
are almost always free. On approaching nearer to their bases, the
red colour of the fragments which have fallen down from their sides,
and the rounded pebbles of granite and porphyry which are met
with in the beds of the tcrrents, give the mineralogist pretty plain
intimation of the causes of this change of feature.
VoObaIV, Q
118 Dr. Mac CuLyiocn’s observations
Except in the rolled fragments however, no appearance of granite
is visible as we skirt the sides of Cruachan from Dalmally to In-
verawe. Every where we observe schistose rocks, which have been
laid bare, sometimes by the operation of natural causes, but more
generally by the process of making the road. This schistus possesses
in different places different features. Sometimes it is a compact mica
slate, where the mica and the quartz predominate by turns, but
its more general tendency is toward clay slate, of which it often
exhibits very well characterized examples of various colours, vary-
ing from dark lead-grey to pale greyish-green. ‘These in many
places, and particularly where in contact with the veins about to be
described, assume an extreme degree of hardness, putting on the
aspect of that which is called Lydian stone and flinty slate. It is
impossible to assign the breadth of the zone occupied by these schis-
tose rocks, as, independently of the turf upon the sides of the hills,
the lower skirt is clothed to a very considerable elevation with an
impenetrable covering of mixed coppice and underwood. It igs
probable however, that the incumbent schistus does not any where
extend very high, as it may be found terminating at a low elevation
on that part of the hill which is naked and accessible, and which
impends over the course of the river Awe.
Numerous veins, of very variable but generally large dimensions,
appear traversing this schistus throughout the course | have described.
They are of various composition, but consist in general of different
coloured porphyries. Their directions are as various as their colours,
but their position is generally perpendicular, or nearly so. Together
with these veins of porphyry, a few veins of trap, exhibiting the
several aspects of greenstone, greenstone-porphyry, and even of
genuine basalt, may be observed; and, from some fragments of
amygdaloid which I picked up by the road side, it is probable that
bes
acl
on the Mountain Cruachan. 119
more numerous varieties which did not come under my observation
may be found to exist.
Arriving at the high bridge which crosses the river Awe, the
mineralogist will be surprised to meet with a secondary stratum in
a situation certainly as unexpected as can well be conceived. A
small portion of it only is denuded by the action of the river, and
exhibits two distinct beds, the lowermost consisting of the well
known red sandstone spotted with white, which occurs near Dumbar-
ton, in Arran, and elsewhere, and the uppermost of a coarse grained
white calcareous grit. This stratum is elevated at a small angle, and
shelves away towards the side of Cruachan as if it was about to dip
under the mountain: its junction with the primary schistus is not
visible. I could not trace it upwards on the opposite side of the
river in the direction of the stratum, although it is probable. that
from the red colour of the soil some portion of it exists where the
road is made. It may be traced a little way down the course of the
river, but the ground being much encumbered and difficult to ex-
amine, it soon disappears. I attempted in vain to find it on the flat
tract at Bunawe, nor did I succeed any where from Tyanuilt to the
sea in recovering any portion of this stratum; the low land being
always covered with alluvial matter, and the denuded rocks appearing
every where to consist of schist and granite traversed by veins of
porphyry. It affords a remarkable example of a deposit of secondary
rock, not many hundred yards square, entangled in the middle of a
primary district, and separated, apparently by many miles, from any
other similar rock. I shall hereafter however attempt to give a
general sketch of the connection of Cruachan with the surrounding
country, when the recurrence of the same circumstance will be de-
scribed, which, if it diminishes the surprise at first excited by its
solitary and unconnected appearance here, increases its general in-
Q2
120 Dr. Mac CuxLiocn’s observations
terest, while it naturally leads the geologist to inquire into the state
of things under which so remarkable a dismemberment of these strata
_ has taken place.
In quitting this part of the skirt of Cruachan it is necessary
either to rise to a considerable elevation, crossing above the woods
of Inverawe, or to avoid it altogether and make a circuit by Bunawe.
We then reach the shore of Loch Etive, and may continue our ob-
servations on the base of the mountain. As we ascend to cross
the foot of the hill granite appears exclusively, generally in the
shape of loose blocks accompanied by similar pieces of porphyry,
but sometimes z# situ. On reaching the shore beyond Bunawe the
appearances become more interesting. The junction of the granite
with the schistus is here clearly seen. Large veins may be observed
proceeding from the great mass of the mountain, and ramifying into
innumerable small divisions penetrating and traversing the schistus
in every direction. No where can this appearance which has excited
so much attention, be more distinctly perceived, and it is moreover
attended here by some interesting circumstances, which as far as I
have observed do not occur in the junctions at Loch Ranza, in Glen
Tilt, or at Locheil. T'wo distinct varieties of granite appear in this
place; the one a granite according to the strictest acceptation of the
term, consisting of reddish felspar, quartz, and mica; the other a
syenitic granite, or a compound of white felspar, mica, and horn-
blende. ‘These are coexistent in every respect and seem to pass
into each other, while both of them ramify in a similar manner
through the schist, a sufficient proof, if any were wanting, of the
geological identity of these two rocks which have so improperly
been distinguished by the accidental presence or absence of the single
ingredient hornblende. Although the granite veins sometimes run
through the schist in a distinct form, just as they do in the junction
on the Mountain Cruachan. 121
of Loch Ranza, yet in many places they are intermingled with it in
a very remarkable manner. Crystals of the hornblende may be
observed shooting far into the body of the schist, so as to render it
often difficult to assign the limits of each rock. In a less degree the
quartz and felspar exhibit the same appearance. Together with this,
the schist is singularly contorted, being bent, broken, and inter-
mingled in a most confused manner with the rock that traverses it,
while distinct detached fragments are often involved in the mass of
granite. In many instances these fragments either exhibit at their
edges a change into a substance resembling basalt, or are actually
converted into a black matter which has at first sight the aspect of
a fine grained hornblende rock or a basalt of the blackest hue, and
which only an accurate inspection discovers to be modified fragments
of ‘schistus. ‘The schistus in general which lies in the immediate
vicinity of the granite vein is highly indurated and gives fire readily
with steel: in other respects it retains its general character, a lami-
nated structure and alternating stripes of colour.
Independently of the peculiarities now described which charac-
terize the junction of the granite with the schist at this place, the
passage of the porphyry veins may be observed in great perfection,
and as they form an important feature of the character of Cruachan
and occur in all parts of it, I shall here describe them at some
length.
These veins are of different sizes as well as aspects, varying from
the breadth of three or four feet to that of fifty, or more: they are
all very erect, and in a general view appear perpendicular. ‘They
traverse both the schist and the granite, and are to be observed in
this part of the hill, cutting the vein equally with the schist in all
directions, as may be seen in the accompanying sketches. They are
uniformly well defined, neither intermixing in any respect with the
122 Dr. Mac CuLtocn’s observations
granite nor with the schist, nor apparently producing any disturbance
in the course or direction of these rocks. They are, as I before re-
marked, of various colours and compositions, and two veins may often
be seen running parallel and in absolute contact with each other, with-
out interference or disturbance, the one of a dark red, and the other
of a light grey or some other colour, as represented in one of the
sketches.* They are so numerous that perhaps a fortieth or fiftieth
part of that region of Cruachan which I examined consists of por-
phyry veins. The principal varieties both of colour and composition
which I remarked, are the following, and their basis consists of that
rock which is now by general consent, called compact felspar, but
which has at times been designated by the term hornstone.
Brick red porphyry, the base of compact felspar with imbedded
crystals of the same colour: a very few specks of white felspar
and of greenish hornblende are dispersed through it.
A mixed granular basis of reddish-grey compact felspar, with
crystals of a larger size and paler colour, containing also grains of
pyrites and long slender crystals of hornblende in abundance.
Base of an uniform dark grey compact felspar with crystals of
white felspar.
The same, but with the addition of black mica, hornblende and
pyrites,
A grey ground with very large crystals of pale grey felspar ;
these crystals themselves containing crystals of hornblende. The
base contains crystallized mica.
A purple ground with crystals of brownish yellow felspar.
A brown uniform ground with rare and minute crystals of
felspar.
* Plate 6, fig. 2.
on the Mountain Cruachan. 123
A similar greyish basis with dispersed crystals of hornblende
only.
A basis of hornblende with distinct crystals of felspar; of a
porphyritic character. ;
An uniform mixture of hornblende and felspar, approaching to
common greenstone, and at length not to be distinguished from it.
These latter varieties appear to form a regular series of a transition
from porphyry to trap, of which I shall immediately speak ; first
remarking that besides these leading varieties which I have
now described, there are many others which it would be super-
fluous to notice, as the variations of colour, aspect, and composition,
are endless. ‘Together with the veins of decided porphyry, various
parts of the mountain are intersected by veins of grey rock, having
as I have just remarked, the general character of the trap rocks, and
sometimes porphyritic. Veins of perfectly characterized basalt also
occur in some places, and these, or fragments of them may in par-
ticular be observed in great quantity strewing the top of the first
summit, (that one which is marked by two cairns,) and laying fair
claim to an equal antiquity with the veins of porphyry. It is easy
to procure detached specimens of the junction between the granite
and basalt in great variety and abundance. ‘The line of junction is
in all cases clear and well defined, but does not admit of ready sepa-
ration even after long exposure to weather. My observations on
the base of the hill were terminated here, some way before the
place where the foot of Ben Starive interferes with that of Cruachan,
I have already said that in ascending Cruachan the schist soon
disappears : at the same time the accumulation of soil and the cover-
ing of plants are so great, that it is scarcely possible to meet with
the natural rock for at least half the ascent. Many masses which
124 Dr. MAc CuLtocn’s observations
appear to be in their places, turn out on examination to be only
large rolled stones, and these invariably consist of granite and por-
phyry. It is not till we have attained about two thirds of the
height of the mountain, that the natural rock makes its appearance
in an unquestionable manner. From this part to both the summits
there are abundant opportunities of examination, as immense faces
of it are left uncovered even on the southern side where the acclivity
is easiest. To the north it presents a range of nearly perpendicular
precipices extending many hundred feet down the mountain. The
mass of the mountain is easily seen from this point to consist of
granite. This appears to be of uniform composition on both the
summits, and to be formed of a very equal mixture of reddish felspar
and white quartz with very little mica, nearly resembling the granite
of Cairn Gorm. The porphyry veins which traverse it are here also
as visible as they are below, but if there is any difference they appear
of greater magnitude, and the red variety predominates. There are
immense fissures on the northern side, which seem to have resulted
from the wasting of these veins. It is on the lower of the two
summits, as I before said, that the junction of the basaltic veins with
the granite is visible.
I have remarked in a former paper* that the magnet is much
affected by the granite on the summit of Goatfield. This is still
more strikingly the case in Cruachan, its affections being indeed
stronger here than they are even on many of the basaltic rocks of
Canna. Both the porphyry veins and the granite affect it, but the
former in the greatest degree. Having had occasion to observe
these two instahces of a fact but little noticed, I think it right to add,
that in both cases I found this property confined to the masses which
occupy the summits of Goatfield and Cruachan, and that I did not
perceive it either in the rocks or detached masses at the foot of these
* Vol. 1, page 430.
on the Mountain Cruachan. 125
mountains. I do not mean to say that this is likely to prove general,
but I merely point it out as an accompanying circumstance, to be
confirmed, or perhaps contradicted, by future and more numerous
observations.
Having thus determined the nature of Cruachan itself, it will be
useful to trace its connection with the surrounding mountains, and
in defect of more satisfactory observations, to conjecture by their
external aspect and by analogy, the nature of their composition. It
forms the highest point of a complicated group, which to the south-
east is bounded by Loch Awe, to the south-west by Mid Lorn, and
to the north-west by Loch Etive, but which extends towards the
north-east in a continuous line, uniting itself with the ridges of Schi-
hallien and Ben Lawers. The part of this group which the great
elevation of Cruachan brings almost immediately under the eye, is
coextensive on the three quarters first enumerated with the boun-
daries there mentioned. To the north it does not extend further’
than Buachaille Etive, while it is in some measure separated from
the eastern mountains by the lower land of the Black Mount over
which the military road passes. Within this space the whole of the
mountains, including both boundaries of Loch Etive, appear to con-
sist of granite, and to be of the same composition with Cruachan ;
there being no perceptible difference either.to the naked eye, or
when seen through the telescope, between their general outline,
fracture, mode of disintegration, colour, or form. How far this
conjecture may be confirmed by actual examination, or to what
extent they may resemble it in the minor circumstances, the inter.
sections of porphyritic veins, can only be known by inspection of
the rocks themselves, a task not likely to be soon accomplished,
gince it is scarcely possible to discover a mode of traversing this
VOL. IV. R
126 Dr. Mac CuLiocn’s observations
region, which, in addition to its extent and difficulty, is nearly void
of inhabitants. Whether it be well founded or not, the rocks which
form this mountain can be traced, under certain modifications, beyond
the boundary here mentioned, and as they add useful illustrations
to the subject, while they also serve the purpose of determining a
difficult tract in the geological topography of Scotland, I shall make
no apology for describing them.
Granite is found at Balahulish, extending round the shore of
Loch Leven on its southern side towards Appin, assuming during
this course, various aspects; but it is generally grey and small
grained, and of the most ordinary appearance and composition,
consisting of quartz, mica, and felspar. Superadded to these, it
frequently contains hornblende, or else it consists of quartz, felspar,
and hornblende, a circumstance which as I have before remarked
forms no distinction geologically considered.
It appears here to be the basis on which micaceous schistus and
‘quartz rock repose, both of which conjoined form the group of
mountains called Ben na vear, which rises above the house of
Balahulish. It is not necessary for the purpose I have now in view
to inquire into the further extent of these rocks. Branches of the:
same granite in no way altered in character pass through the schist,
and probably the quartz rock, although I did not detect their actual
junction with this last. I can only conclude that as the schist and
quartz rock alternate, that vein which traverses the one must also
traverses the other. The schist which is traversed by the granite |
often much indurated, and approaches by various undefinable gra- .
dations to a sort of hornblende slate. Masses of a similar substance
may be found imbedded in many parts of the granite. Occasion-
ally these masses appear on close examination to be only irregular
spots of hornblende, such as occur not unfrequently in those gra-
on the Mountain Cruachan. 127
nites of which this mineral forms an ingredient. More often how-
ever their shape is perfectly defined, and they appear to be lamine
of which the edges are truncated or broken at angles with the plane.
In some places this appearance of fracture is so precise, that when
two fragments occur together in the granite the imagination as
easily replaces the separated parts as it does in the brecciated mar-
bles or agates: nay, further, the fragment will sometimes be
found to consist of an argillaceous or slightly micaceous schistus,
maintaining this character with scarcely a perceptible alteration,
and sometimes only approaching to hornblende schist at its exte-
rior parts. It is also worthy of remark that these fragments some-
times exhibit at their edges stripes of different colours and degrees
of hardness, arising from the varying texture of the laminz which
compose them. ‘The masses vary in size from an inch to a foot
and upwards, but whatever their size may be they have almost in-
variably parallel sides. ‘The examples of this appearance are very
numerous both at Balahulish and in the rolled fragments of granite
which are spread over the Black mount to the eastward of Glenco,
and we shall presently see that the same granite with similar con-
nections occupies a very large tract of country. The frequency
of the occurrence also enables an observer to examine the specimens.
without difficulty, and to compare their various aspects and circum-
stances. From these I have no scruple in saying, that the granite.
now described contains fragments of schist imbedded in its mass,
generally so altered in their original appearance by their connection
with the granite, as to approach to, or partially to assume the
character of hornblende slate, but often also possessing the characters
of micaceous schist unchanged, and under all the varieties of aspect
by which it is characterized,in the surrounding country.
R 2
128 Dr. Mac CutLocu’s observations
I shall continue to describe this rock as far as I have traced it,
, Since if not strictly a part of the professed object of this paper, it
will, in addition to the contribution which it forms to the mineral
topography of the country, either assist future geologists in con-
necting their own observations, or present them, in a tract among
the most desert and difficult of access in Scotland, with a point of
departure from whence they may prolong their observations over
the adjoining country.
In leaving Balahulish to proceed westward we almost imme-
diately lose sight of the granite, which occupies here only the lowest
position, and is scarcely to be found above the level of the sea,
The schistose rocks which cover it do not however accompany us
long, being succeeded at the mouth of Glenco by a mass of rocks
appertaining to the porphyry family, which I shall recur to when
I have traced the granite. This becomes again visible as we ap-
proach the King’s house, and, quitting the rugged hills which
separate Glenco from Loch Etive and from Loch Leven, enter
upon the wide, trackless, and solitary moor of Rannoch. This
extensive and barren tract is elevated at a very considerable height
above the sea, and, although unascertained, it probably does not
fall much short of a thousand feet. Its surface in a general sense is
flat, when compared with the ordinary aspect of a Highland moor,
yet it is diversified by low rocky hills and undulations, covered
with a deep peat which conceals the subjacent rock. There are
notwithstanding abundant indications of its nature in the beds of
the streams which flow over it, by which the naked rock is com-
pletely exposed to view, while every protuberance which time or
accident has laid bare, and the detached blocks that are strewed over
its surface, confirm its identity with the granite of Glenco. It can
be thus traced to the head of Loch Rannoch, a distance estimated
on the Mountain Cruachan. 129
at 24 miles, with no variation of character ; but of its breadth be-
tween north and south I am unable to speak, the country being
absolutely trackless and uninhabited.
It appears to me however that it extends, perhaps with some
interruption, from the schistose rocks to Ben Vualach by which it is
connected with the granite district of Loch Ericht; and there is
equal reason to suspect that to the westward of this it will be
found similarly connected with the granite of Ben Nevis.
Where it terminates, at the head of Loch Rannoch, it forms
hills of moderate elevation, and these are immediately followed
and covered by a succession of schistose rocks, consisting of quartz
rock, micaceous schist, and an obscure variety of gneiss which I have
already had occasion to describe in another place.* The junction
of the two may be observed in different places, in all of which it
is invariably accompanied by the appearances already noticed at
Balahulish, namely, fragments of the different schists imbedded in
the granite.
The schist which is here imbedded in the granite is often composed
of black scaly mica with a high lustre. Towards the junction of the
fragment with the surrounding rock it generally contains crystals
of hornblende. The fragments vary much in size, and I must add
that they differ completely in aspect from those accumulated plates
of mica which are found in the granite of Aberdeen, as well as in
many other granites. In other cases the imbedded fragments con-
sist of the same quartz rock and gneiss which form the general
body of these.schistose rocks. If any mineralogists are unwilling
to consider them as imbedded fragments, it can only be said that
if they were really detached fragments they could possess no other
aspect than that which they now have. ‘The head of Loch Spey,
* Vide Paper on Quartz Rock, Vol. 4.
130 Dr. Mac Cuixtocn’s observations
a tract far removed, yet possibly not unconnected with this, is also
composed of granite; and among this are found perfect granitic
conglomerates, in which fragments of mica schist, equalling in
quantity the substance which connects them, are seen imbedded
in a paste of granite.
Occasionally the fragments are confounded with the mass at their
edges, but at times they are so defined, and even so separable, that
I procured a specimen with the distinct vacant impression of a rec-
tangular fragment which had probably been detached. Cavities left
in this way by the wearing out of the schist occur frequently in the
rocks throughout the moor of Rannoch. The union between
granite and the schists which it touches when passing through
them in the form of veins, is known to be subject to similar
variations. I may here add that the same appearances, though
more rarely, may be found in Mar, and in the granite which occurs
near Comrie.
It is well known that the passage of granite veins through schist
is commonly well defined, and that the two are generally easily se-
parable by the action of the weather. But the district of Rannoch
offers a multiplicity of veins which are so confounded with each
other and with the rocks which they traverse, that their appearances
cannot be described. ‘They frequently vanish so imperceptibly both
in the quartz rock and the mica slate, that a perfect passage from the
one to the other is visible, while the accessions of additional veins,
traversing and often shifting the already intricate structure, increase
the unexampled confusion which reigns among them. The granite
is often found imbedded in detached lumps in the schist, and I
must remark of these lumps and veins, however minute they may
be, that contrary to the granite veins and detached masses of Glen
Tilt or Corpach, their character is perfect even to the minutest division.
on the Mountain Cruachan. 131
I shall add but one remark more on this subject. Although the
schistose rocks are seen only at the two ends of this prolonged tract
of granite, the imbedded fragments can be traced throughout the
whole. Hence it might be supposed that they were independent
of the vicinity of the great schistose masses, whereas in the view
which I have taken of them I consider them as connected with and
dependent on them. It is plain that the absence of schist at present
from the surface of the granite which forms the moor of Rannoch,
proves no negative in this case, as we have abundant examples every
where of the removal of great tracts of rock from parts of the earth’s
surface, and of the consequent denudation of the inferior substances ;
a change which may easily be conceived to have occurred here, thus
leaving exposed that very surface of the granite which once was in
contact with the superincumbent beds of schist.
Having thus traced the granite district of which Cruachan
forms the most conspicuous portion as far as means of observation
were afforded, I shall point out, under similar limitations, the por-
phyry which fell under my notice, since it will tend to illustrate the
great predominance of the porphyritic veins in that mountain, as
already described. 1 must however say that I consider the few fol-
lowing remarks, like those on the granite of Balahulish and Rannoch,
in no other light, since they cannot be viewed even as a sketch of
one of the most complicated and interesting districts in the whole
range of Scottish geology. It will presently be seen that the great
extent, the divided disposition, and the almost impracticable nature
of the country throughout which these rocks are scattered, would
require a very different investigation from that which a few distant
and rapid visits permitted me to bestow on it. i
The various schistose rocks, consisting of quartz rock, mica slate,
132 Dr. Mac CuLtocn’s observations
clay slate, and limestone, cease at the place where Glenco first begins
to contract its dimensions as we proceed from Balahulish eastward.
From this point till we arrive at the King’s house, or near it, the
mountains on each side consist of porphyry, or of the different
simple substances which form its bases, these simple rocks being
indeed much more prevalent’than those which are, strictly speak-
ing, porphyritic. As these hills subside at their eastern end in the
moor of Rannoch, the mass of porphyry disappears, and is suc-
ceeded by the granite already described; but veins of all the dif-
ferent varieties are found connected with it, every where intersect-
ing the latter rock, and although gradually diminishing in frequency
as we recede from the great mass, still admitting of being traced even
to its very extremity. I have no means of assigning the boundary of
this porphyry towards the north, but as the same rock is found to
form the summit of Ben Nevis, it is probable there is some connec-
tion, more or less interrupted, between them. It is easily seen that
towards the south it forms both the mountains which go by the
name of Buachaille Etive, the conoidal and acute forms of which
are visible from a great distance throughout the surrounding country.
From these it extends along the eastern side of Corrich y bae, but as
the southern sides of their declivities have not been examined, it is
impossible at present to state the limits here between the porphyry
and the granite which I have conjectured in a former part of this
paper to extend from those mountains to Cruachan.
The vertical structure of this rock explains the cause of the abrupt
and perpendicular faces which give the peculiar character to the dark,
solemn, romantic Glenco. ‘Together with that it presents the same
laminar tendency which is so remarkable in the rock of Devar, de-
scribed in a former paper.* In many places there is an appearance
* Geol. Trans, Vol. 2.
on the Mountain Cruachan. 133
of veins proceeding from the mass, rendered conspicuous by their
projection and superior durability, but in examining the surround-
ing rocks where in contact with them, no difference of structure or
composition is perceptible. I did not any where perceive a ten-
dency to the columnar form.
Although the naked surfaces of these rocks might lead us to sup-
pose they were inimical to vegetation, this effect must rather be
attributed to the steepness of their declivities, which prevents the
accumulation of soil. From whatever cause it may arise, they seem
particularly subject to be destroyed by the action of the mountain
torrents, whence the enormous piles of fragments which annually
overwhelm the road and are fast raising the level of the valley.
The simple rock, which, as I have already said, prevails over the
porphyritic varieties, is at one extreme a claystone, and at the other
a compact felspar, varying through several intermediate stages of
hardness. In the intermediate stages of transition to porphyry, a
single crystal only ‘of felspar will sometimes be found in a large
fragment, the ultimate accumulation of which produces porphyries
of an infinite variety of aspects. Every variety of this substance
indeed, whether in colour or composition, which occurs in veins
throughout Scotland, is here found mixed together in the mass,
sometimes placed side by side with a sudden and decided transition,
at others graduating into each other by imperceptible degrees. The
colours graduate into each other in these cases just as do the dif-
ferent structures, and among these gradations the most striking are
those where black passes into red. It would be an useless task to de-
scribe the varieties of colour which occur, but the different shades of
grey, purple, and red, are the predominant ones. In some cases
dark blueish specimens are found veined with red, producing very
beautiful and remarkable varieties: in others, the red colour is so
VOL. Iv. $ |
134 Dr. MAc CuLtocn’s observations
bright, and the texture so compact, that they can scarcely be dis-
tinguished from jasper, a rock which, I may remark, although
hitherto but little examined in its geological relations, possesses a
very near affinity to the family of porphyry, as well in the extensive
independence of its position among the regular rocks, as in its ap-
pearance and composition. .
The occasional minerals which are found in these rocks are
hornblende, quartz, and epidote, all of them entering into the com-
position of some of the varieties, and the latter in particular form-
ing a very conspicuous feature among them, being disposed either
in the form of veins, or in amygdaloidal cavities, or else in occasional
grains. Hard breccias, of which the structure can scarcely be detected
except on the weathered surfaces, and exactly resembling those so
conspicuous on Ben Nevis, also occur dispersedly among the more
simple rocks, the fragments consisting only of different varieties of
the same substance.
Before quitting these rocks it will not be uninteresting to mark
the principal circumstances in which they differ from the analagous
rocks which occur in Arran, in the Ochil hills, and in many other
parts of Scotland. They all consist alike of claystone and compact
felspar, simple or porphyritic. But they differ in situation, the hills of
Glenco reposing on granite and the older schists, while the former
lie above the red sandstone. They also differ in their general
features, since the former assume a spiry shape, while the others
present a succession of tame and rounded outlines. ‘They appear.
equally to differ in durability, since although the hills of Glenco are
destroyed by the effects of the mountain torrents, they are not like
those of Arran subject to decompose by the ordinary action of the
atmosphere. In the variety of composition there is also a con-
spicuous difference, the infinite number of hard, coloured, and com-
on the Mountain Cruachan. 135
pounded porphyries that occur in Glenco and correspond with those
which are every where found in veins among the older rocks, being
entirely absent in those which lie above the red sandstone. Are we
to attribute these diversities to a different era of formation? Unfor-
tunately our knowledge of these rocks is as yet so limited that this
question cannot be answered; but the few remarks which precede
may for the present remain as slender contributions towards their
history, independently of the local interest they may possess in
illustrating the description of Cruachan.
The next rock of which it is necessary to take a somewhat more
extended view, for the purpose of illustrating the structure of this
mountain, is the red sandstone, together with the white calcareous
sandstone which }'es above it. As the former is of frequent occur-
rence while the laticr is only occasionally present, and as there is no
difficulty respecting the consecutive position of these rocks, I shall
neglect it in the short notice here to be given.
It has been shewn that these sandstones occur at the foot of the
mountain, occupying a very small space, and that no continuation
of them can be traced to the immediate vicinity. But in traversing
a larger portion of this tract of Argyleshire a similar phenomenon is
found frequently occurring, which, if it diminishes the suprize at
first excited by this very limited extent of the secondary strata in the
spot above described, adds a much greater interest to the fact, while
it naturally leads the geologist to enquire into the circumstances
under which so remarkable a dismemberment of these strata has taken
place. Their continuity and extent as they occur on the eastern and
southern skirts of the highland mountains are too well known to
require notice, and they will be found to occupy an extent similarly
continuous, as far as geographical circumstances will permit, on the
s 2
136 Dr. Mac Cutuocn’s observations
north-western coast of Scotland and in the islands connected with it.
The interval between these two principal masses of sandstone may
be said, in a general way, to extend from near the Mull of Cantyre
to Kintail, and the predominant rocks throughout this space are
gneiss, micaceous schist, quartz rock, and a variety of analogous
substances which it would be out of place to enumerate here.
It is in this interval that the scattered fragments of the sandstone
strata are to be occasionally found, sometimes like that near the foot
of Cruachan, connected only with the more ancient rocks, in other
places associated with and covered by a variety of rocks more or less
appertaining to the trap family, or to the porphyritic rocks which
accompany them. It would lead to a length of description unfit
for this paper to describe the places where they are to be seen, but
I may mention two which are remarkable on account of the narrow
space which the sandstone occupies, still more limited than even in
the spot which has led to this discussion, These are the island of
Seil, and Inish capel, in the latter of which their total extent only
amounts to a very few yards. It is remarkable that in all these cases,
as far at least as I have examined them, their dip is toward the west,
however limited this may be, and that this is also the dip of the
leading masses both at the southern side of the interruption above
quoted and at its northern extremity where the same strata are
found occupying parts of many of the islands, and extending for a
considerable space between Kintail and the Ru Storr in Assynt.
The uniformity of their dip proves that these independent masses
have not been separated by any disturbance from below, and we
have therefore to chuse only between two explanations ; either that
they had been originally independent deposits, or that they had
formed one mass subsequently disjoined either by the operations of
water or of other destroying forces acting on the surface, or else
on the Mountain Cruachan. 137
by the intrusion of some other rock. The uniformity of their
dip seems a sufficient reason to reject the former explanation, and
their present appearance is more probably derived from both the last
mentioned causes acting on different points. Concerning the action
of water or other similar causes we can only conjecture, but of the
latter we have occasional proof in the actual existence of masses of
trap rock overwhelming them in some places, and doubtless con-
cealing them entirely in others. It may perhaps be owing to this
rock and to its subsequent destruction only, that their present state
is to be referred. I shall therefore conclude these illustrative re-
marks by a few words respecting the trap rocks which occur in the
vicinity of Cruachan, and which are in many places so intimately
connected with these detached portions of the secondary strata.
The nearest mass of these substances is a long mountain ridge
which occupies part of the northern shore of Loch Etive, descend-
ing towards the western sea and skirting the plain of Connel.
It is in this place well known to all who have travelled the west
Highlands, since the road passes under large rocks of the conglo-
merate which is connected with it. It is equally familiar to
those who visit Oban, since the surrounding country and the
neighbouring islands are covered with more or less extensive
masses of it, in some cases reposing on the older schists, which
form the visible basis of this country, in others upon the sand-
stone strata already described. It is in this latter case that it pro-
duces the effect already alluded to of partially concealing the
masses of sandstone, so as to give an appearance of separation
where no real one exists. In some cases it 1s also probable that
it has actually dislocated and separated them, intruding among
them as all the rocks of this family do, from below. Hence it
assists us in explaining the state of the sandstone formerly described,
138 Dr. MAc CuLtocn’s observations on the Mountain Cruachan,
although, from the circumstances already mentioned, that separa-
tion is in many cases independent of it. It is far beyond the
bounds of this paper to pursue further the very interesting circum-
stances under which the whole of this formation of trap appears ;
and I shall probably take some future opportunity of entering at
large into its history. I shall here therefore terminate these miscel-
laneous remarks, which appeared to me necessary to illustrate the
description of Cruachan. |
V. Account of some remarkable Disturbances in the Veins of the Mine
called Huel Peever, in Cornwall.
By JOHN WILLIAMS, Junr. Ese.
HONORARY MEMBER OF THE GEOLOGICAL SOCIETY.
[Read 2d June, 1815. ]
Tur county of Cornwall, in whatever part it has been explored
in the working of its numerous mines, has been found so devoid of
perfect regularity and agreement, either as regards the course, dimen-
sion, or contents of its veins, or the uniformity of the country they
traverse, that the history of any one mine can by no means be
considered as exhibiting a portrait of them in general. Each mine,
not to say each vein, will be found to have some peculiar claim to
attention. It is not perhaps hazarding too much, to presume that a
knowledge of what occurs, even to the limited depth to which the
Cornish veins are followed, may be found to throw some light on.a
branch of science which is yet involved in considerable obscurity,
but it is to be lamented that facts have not hitherto been sufficiently
attended to with a view to their preservation. The object of the miner
is the most expeditious manner of arriving at gain; his knowledge
is derived from the book of his own experience: but so greatly do
the circumstances attending veins differ, that they sometimes set at
defiance his experience, however great or general it may be. Some
of the most interesting phenomena attending the veins of Cornwall are
the interruptions they meet with from each other ; these are of various
140 Mr. WILLIAMs’s account of the
descriptions. In the mine of Huel Peever, which is the object of
this memoir, almost every species of interruption occurred to which
the veins of Cornwall are liable; and so completely was the skill
and experience of the miner baffled in the progress of its workings,
that its tin vein having been heaved (to use a technical phrase) by
other veins, it was not discovered again by the exertion of much
labour and expense during a lapse of nearly forty years. It may perhaps
serve to render more intelligible the following description of the
remarkable circumstances attending the veins of Huel Peever, if we
notice on the subject of veins in general that those of which the
direction is north and south are rarely metalliferous; that the veins
containing copper and tin run, with little exception, about east and
west. Their downward direction is seldom quite vertical ; there is
however a species of vein having also an east and west direction
which is never metalliferous, but consists generally of clay ; this vein
is for the most part found to take a course under-ground much less
approaching the perpendicular than the metalliferous veins. This
variation from the perpendicular in an east and west vein, whether
it be towards the north or south, is called the underlie, and when its
direction or dip is opposed to that of the metalliferous vein, it mostly
disturbs the direction of the latter. ‘The east and west non-metal-
liferous veins either from their customary effect in respect to other
veins, or from their generally quick underlie, or from both, have
obtained the name of slides.
The mine called Huel Peever is situate in the parish of Redruth,
about one mile and a half north-east of the town of the same name.
Its veins, to the extent of their workings both in length and depth,
were found to pass only through schist, occasionally of a micaceous
appearance, but in many parts the mica not being perceptible, it
assumed the character of argillaceous schist.
Veins in the Mine of Huel Peever. 14]
By a reference to the accompanying ground plan of the mine,
Pl. 7, fig. 1, it will be seen that it consisted of one tin vein a and
one copper vein 4; the latter called John’s Gossan, running in
the direction of east and west, and forty fathoms south of the
former; two other veins c and d not metalliferous, took the same
direction, one 25 fathoms south of the copper vein, and the other
23 fathoms still further south. Mary fathoms north of the tin vein,
but at what exact distance is not precisely known, a channel of por-
phyry f, or in the language of the miner, of elvan, also ran in the
direction of east and west, and a copper vein e near it. It will also
be seen that there were three cross veins, not metalliferous, techni-
cally called cross courses, the easternmost of which x runs from
10 degrees west of north to 10 degrees east of south, that next to
it y, about 9 fathoms to the west, runs a little more to the west of
north, and east of south. The precise direction of the westernmost
z, which was 145 fathoms distant from that next to it on the east,
is not known; nor is that essential to the present object, since as it
formed the utmost limits of the workings of the mine on the west,
and was situate in the poorest part, it was not found to contribute
any thing towards the strange circumstances which have rendered
the history of this mine so well deserving of detail and preservation.
The tin vein @ is from three to thirty feet wide, but its general
average may be estimated at about eight feet. The copper vein 4 is
about three feet wide. It is almost needless to observe that these
veins were not equally productive in every part; in some places,
they were very rich, in others quite poor ; but it is worthy of notice,
that where the tin vein was thirty feet wide, its substance consisted
of a mass of rich tin ore extending several fathoms in every direction.
The substances enclosed in the copper vein, consisted, near the sur-
face, of quartz and iron ochre, or gossan, amongst which was inter-
VOL. Iv. wi
142 Mr. WitiraMs’s account of the
spersed a little yellow copper ore, accompanied by quartz, chlorite
and iron pyrites to a considerable depth. Both the tin and copper
veins have been traced for about a mile in length.
The two slides which run parallel with the metalliferous veins
afforded no trace of either copper or tin. The northernmost
of the two is from 4 to 12 inches wide; the southernmost from 2 to
3 inches. They were found to consist wholly of an argillaceous
clay, called by the miner flucan. These veins, as will hereafter be
seen, notwithstanding their poverty, were one principal cause of
the remarkable incidents attending this mine.
It will be seen by the ground plan that the eastern cross course x,
(which was about 4 feet wide, consisting of 3 feet of quartz on the
western side, and G6 inches of flucan on the eastern,) traversed the
channel of porphyry, the tin and copper veins, as well as the two
slides, heaving them all 54 fathoms to the north on its western side,
where they maintain the same distance from one another as on the
eastern side. The cross vein y next on the west, which consisted of
the same substances as the cross vein x, and on the surface where it
cut the tin vein at P was distant from it only about 26 fathoms, had
precisely the same effect on all the east and west veins, except that
the distance of the heave north was only 18 fathoms, so that the tin
vein, at its place of contact with the west side of the cross vein y at
P was exactly 72 fathoms north of that part of it in contact with
the eastern side of the cross vein » at Q. Of the cross vein at
the western extremity of the mine, (as has before been noticed) little
is known. But the two former have been traced nearly five miles
in length intersecting every tin and copper vein, and from every
observation, it seems probable that they extend from the Bristol to
St. George’s Channel, and are very distinctly seen in the cliffs near
Porthtowan on the northern coast.
Veins in the Mine of Huel Peever. 143
The intersection and heave of the east and west veins by the
north and south veins in Huel Peever, form an interesting part in
the detail of its history; although such occurrences are by no
means rare, as they are found to exist in a greater or lesser degree
in almost every mine traversed by north and south, or non-metal-
liferous veins. But some remarkable and almost peculiar circum-
stances belonging to the downward direction or underlie of the
several veins in Huel Peever remained to be noticed: these are of
so complex a nature, as to render a verbal description difficult ;
but they are of great interest in a geological point of view.
The channel of porphyry, and copper vein near it, being in no
degree connected with the ensuing detail, are wholly omitted in the
accompanying transverse section,* which represents the underlie of
the tin, copper and flucan veins on the west side of the cross vein y.
The underlie of the tin vein is towards the south, 2 feet in every
fathom, that of the copper vein is towards the zorth, 4 feet in a
fathom, so that the horizontal distance between them at the surface
being 31 fathoms, they would have come in contact at the depth
of about 31 fathoms, but for the intervention of the flucan vein
on the south of the copper vein. The underlie of this flucan is
towards the north, and much quicker than that of the copper vein,
being about 14 feet in every fathom; and by the transverse section
it will be seen that the flucan overtook the copper vein at A, and
cut it short at the distance of about 22 fathoms, measured along
its inclination, from the surface; whence pursuing its direction
in a strait line about 14 fathoms, it met with, and in like manner,
interrupted the course of the tin vein at B at about 26 fathoms
measured along its underlie, or 24 fathoms perpendicular from the
surface ; after which the flucan or slide proceeded regularly.
*: PY. 7, fig. 3.
a
144 Mr. WiLLiAMs’s account of the
It next became the object of the miner to discover the parts of
the copper and tin veins, which had been severed and carried away
by the flucan. This after much Jabour and expence was effected.
On pursuing the downward direction of the flucan vein, after it
had quitted the tin vein at B, it was found that the copper vein
had been carried down about 18 fathoms from A to C, and the tin
vein as much from B to D.
The working of the tin vein being the object of the miner, he
found it proceeding in its underlie from D in the same direction as
it had assumed between the surface and its place of intersection with
the vein of flucan at B; but after sinking upon it about 9 fathoms,
it was found (to use his phrase) cut out by the copper vein at E,
whence a new and unlooked for delay and expense were incurred.
It was at length discovered that the effect of this intersection was
immediately opposed to that occasioned by the flucan vein, for the
tin vein was as it were, heaved up by the copper vein 8 fathoms
to F, whence it resumed its customary underlie and direction, and
was followed for about 42 fathoms in depth to G, where it was
intersected by the south slide d, by which it was heaved up about
nine feet; it afterwards continued its course downwards as before,
and was worked about 38 fathoms below to H. ‘The south slide
underlies towards the north about six feet in a fathom. |
The accompanying longitudinal section of Huel Peever is along
the run of the tin vein, and supposes its south side or wall taken
away in order to exhibit the workings of the mine; and for the
same reason also supposes a perfect continuation of the tin vein
from the eastern side of the western cross vein z to the western
side of the eastern cross vein x, although the fact was, as has
been already noticed, that the tin vein was separated by the
slide at 26 fathoms on its underlie from the surface, and carried
Veins in the Mine of Huel Peever. 145
away 18 fathoms towards the north, and also that the tin vein was
18 fathoms further north between the western and the middle cross
vein than between the latter and the eastern cross vein. The
workings to the east of the latter are not exhibited in the longitu-
dinal section, in consequence of its being another mine called Old
Huel Peever.
By the longitudinal section it will be seen that the downward
direction of the eastern cross vein x, towards the west, was 4 inches
in a fathom, the underlie of that 17 fathoms on the west of it at
the surface at y, was towards the west one foot and a half in a
fathom. The underlie of the cross course at the western extremity
of the mine z, was in opposition to the latter, being very little
towards the east, though nearly perpendicular.
cc, ad, Represent the north and south slides intersecting the
tin vein, the former at 25 fathoms perpendicular from the surface
at the engine shaft, and the latter about 50 fathoms below. 9,
shews the situation of the shallow adit or water course, and 10,
the deep adit; all the other horizontal lines represent the passages
or levels made by the miner in the search after tin, or for the con-
venience of his occupation. The dark parts of the longitudinal
section shew the places in which tin was found.
Pl, 7. fig. 3.
VI. Description of the Tunnel of the Tavistock Canal, through
Morwel Down, in the County of Devon.
By JOHN TAYLOR, Esq.
TREASURER OF THE GEOLOGICAL SOCIETY,
{ Read 6th May, 1814.]}
MoorweEL Down is a hill, lying between the River Tamar,
which divides the counties of. Devon and Cornwall, and the River
Tavy, which rises in the forest of Dartmoor; and after passing
the town of Tavistock, flows on the eastern side of Morwel Down,
and falls into the Tamar, a few miles nearer Plymouth.
The neck of high land separating these rivers, extends south-
wards from Morwel Down, and includes the parish of Beer, in
which are situated the Beeralstone Lead and Silver Mines, not far
from the point of the peninsula, the lode crossing a part of it in
a line from north to south.
In pursuing the Tavy towards its source, the country rises irre-
gularly, and the rocks are found to consist of killas, to the borders
of Dartmoor; the same appearances are to be observed by taking
a survey of the hills situate between the eastern bank of the river
and the range of granite mountains which form the peculiar feature
of Dartmoor. ‘True granite has not been found intermixed in the
central part of the range of the killas rocks of this neighbourhood,
in any instance within my recollection. In the valley through
Mr. TAytor’s Description, &c. 147
which the little river Walkham flows, and near the point at which
it falls into the Tavy, a remarkable change of strata occurs; the
side of a very abrupt hill, on the top of which is West Down, in
the parish of Whitchurch, is composed of a considerable cluster of
detached masses of granitic rocks, which are piled on each other
in the most picturesque manner, and form a lofty and steep bank
to the river. Killas occurs in the same hill, on each side, and is
the only rock observable on that which rises from the opposite edge
of the valley.*
If we turn from the country on the east and north of Morwel
Down, to that on the west of it, we shall find that the Cornwall
side of the river Tamar is more diversified in the rocks that occur;
killas generally prevails, but granite crowns the summit of Kithill,
which rises gradually from the banks of the river to the height of
1400 feet, and the same rock is to be found near the base of the
mountain, at Gunnis Lake Copper Mine, near New Bridge, and
again a little higher up the stream, at a place called the Clitter, a
provincial word, signifying a collection of loose masses of rock.
The killas district is nearly surrounded on the three sides above
* The situation of these rocks would point out a connexion between them and some of
the beds or veins of porphyry which are to be described as occurring in the tunnel through
Morwel Down; the line of their direction would lead us to this point, and the inference
is strong that this is a part of one of them. It is however rather extraordinary that it
should have escaped notice in the deep valley of the Tavy, where it must pass, and where
I have little doubt it will be found from a recollection of the general features, though un-
fortunately it did not occur to me to Jook for it at the time when I could have done so,
It may likewise probably be traced through Morwel Down to Gunnis Lake Mine, which
is mentioned in the following paragraph.
I do not venture to decide on what this rock should be called; in describing the strata
of the tunnel I have assumed that it is porphyry. That which occurs in the Walkham
valley has much more the character of granite, and so I should incline to call it.
The specimens will enable more competent judges to decide.
148 Mr. TayLor’s Description of the
mentioned by the granite, the line of division of the two rocks
describing an irregular horseshoe form, while the southern side of
the killas extends to the coast and joins the Plymouth limestone.
The surrounding granite mountains rise to an elevation of from
1400 to 1900 feet above the sea, while the hills of killas keep a
much lower range; Morwel Down, through which the tunnel is
passing, is one of the highest in the central part of the killas, and
is about 700 feet above the tideway in the river Tamar, which
washes its base.
The killas district, which is attempted to be here described, is
every where intersected with veins, or as they are technically called,
Lodes. Those which are worked for copper or tin have universally
a direction from north-east to south-west, or nearly so; those
which run in other courses have all the appearances of a newer
formation, and are generally unproductive of metal, if we except
two instances, one of which is the lode on which the Beeralstone
mines are working to a considerable extent, and the other the lode
in Wheal Betsey Mine, in the parish of Mary Tavy, both of which
produce lead and silver. .
In the last 20 years this district has been the scene of very active
exertion in the pursuit of mining, and the most spirited efforts
have been made for tracing the veins, and instituting trials upon
them for the discovery of their contents. These effects, as in most
similar cases, have been attended with very various success, though
on the whole, the result has been a favourable one. On many
lodes considerable sums of money have been expended, without
discovering sufficient quantities of ore to repay the disbursements,
and on many the loss has been heavy ; in other instances, though
the fewer in number, mines have been established which have pro-
duced very large quantities of ore, principally of copper, and have
paid the adventurers very handsome profits.
Tunnel of the Tavistock Canal. 149
The most important of these mines are Wheal Friendship, in the
parish of Mary Tavy; Gunnis Lake and Drake Walls mines, in
Calstock, on the Cornish side of the Tamar ; Wheal Crowndale, on
the banks of the Tavy, below Tavistock; Beeralstone mines, in the
parish of Beer ; Wheal Betsey, in Mary Tavy ; Wheal Crebor, at the
foot of Morwel Down, discovered in consequence of the under-
taking about to be described, and some others of inferior note.
I am not able to state any account of the produce either of Guznis
Lake copper mine, which has been very considerable, or of the
Beeralstone mines, but exclusive of these the others have returned
since the year 1805, from 3 to 4000 tons of copper ore annually,
and the quantity now raising is at the rate of at least 5000 tons in
the year. There has likewise been a considerable quantity of lead
raised at Wheal Betsey, .and of tin at Drake Walls.
All the lodes that have been worked, are in killas, excepting
that at Gunnis Lake, where the copper is found in granite. The
ores of this mine differ very much from those of the other mines;
those of the latter are almost entirely copper pyrites or yellow cop=
per ore, varying in their proportions of metal from 5 to 15 per cent.
while in the former mine are found besides the yellow copper ore,
carbonates of copper, grey copper ore, arseniates, &c. This fact is
the more striking, as the vein is certainly the same as that worked
at Wheal Crowndale and Wheal Crebor, where it traverses the
killas, and at Gunnis Lake passes into granite.
About the year 1802, when the mines of this district were as-
suming an importance they had never before attained, and their
prospects were such as to encourage fresh adventures, the pro-
prietors of the principal ones were led to think of the scheme of
driving a tunnel through the hill, which is the subject of the pre-
sent remarks. The chief inducements were, that Morwel Down
VOL. Iv. ; U |
150 Mr. TAayLor’s description of the
was known. to be traversed by numerous lodes, which might be dis-
covered and worked by such an undertaking, and that while a tun-
nel should be carried in a direction to cross them all, it might make
a navigation practicable from the vicinity of Tavistock and the
adjacent mines, to the river Tamar where the produce of the neigh-
bourhood is shipped.
In 1803 an Act of Parliament for cutting a canal from the town
of Tavistock to Morwelham, a quay on the river Tamar, was ob-
tained, and the driving the tunnel was immediately begun.
A canal from the north end of it to the town of Tavistock was
soon after cut, by which means a copious stream of water was ob-
tained from the Tavy, which was carried across a valley upon an
embankment 50 feet high, and afforded the means of working an
overshot water-wheel of immense power, which was required for
sinking the requisite shafts on the hill through which the tunnel
was to pass.
It is unnecessary here to enter into further detail of the nature
of the works, as they may be understood from a collection of
reports on the subject, which I have formerly laid on the table of
the Society ; it is sufficient to remark that this tunnel, which was
to pass through hard rock for a length of nearly a mile and three
quarters, and for the principal part at a depth of about 130 yards
from the surface of the hill, was an undertaking of no small enter-
prize, and that difficulties of various kinds presented themselves in
its progress.
The tunnel, as may be seen by the section, is not yet complete,*
but the obstacles are all surmounted, and nothing now remains to
be done but the simple operation of driving. The draining the
deep shaft in the centre of the hill, and the ventilation of the tun-.
nel, having been some time since provided for,
* See the Postscript to this Paper.
Tunnel of the Tavistock Canal. 151
It does not often happen that the processes of the miner lead to
so much geological discovery as might be expected ; the works he
undertakes follow the course of the vein he is exploring, or are
confined within a small space bordering upon it. As the veins are
sought after in but very few varieties of rock, so the number that
are laid open to view is generally limited compared with those that
exist in mining districts.
A tunnel of such an extent as the one now to be described, in
such a district, crossing the direction of the metalliferous veins, and
passing at such a depth under the surface, could hardly fail of
proving an interesting object to the geologist as well as the miner.
Two facts have been ascertained by its progress:
Ist, Relative to the rocks, that the killas of which the hill is
mainly formed, is traversed by beds of other rock, whose direction
is inclined to that of the metalliferous veins, and which have a
pretty uniform dip or underlay to the north. |
2d, Relative to the metallic veins or lodes, that they traverse all
the strata, and that they have a remarkable difference in their dip
or underlay on the two sides of the hill. Those on the north side
dipping to the north, and those on the south side to the south.*
Commencing at the north end of the tunnel, I shall proceed to
detail the strata that have been passed through, referring to the sec-
tion accompanying this paper to shew their. position, and to the
specimens of the rocks themselves which I have selected to exhibit
their character.
* Since the paper was written it has been ascertained, as I have been informed, that
some veins lately discovered in the space between Renfrews shaft and Brays shaft underlie
to the south, which is an exception to the preceding observation. But it may be observed
that this deviation takes place near the centre of the hill.
u 2
152 Mr. TAYLOR’S description of the
I give the provincial names of the rocks as they are in general
use among the Cornish miners.
A — 311 fathoms Killas
Boos Ad Elvane Chlorite and Quartz
Cc — 23 —— Killas
D — 6 —— Grouan Clay Porphyry
E — 12 —— Killas
F — 26 -——— Grouan Chay Porphyry
G — Killas
H? _ 436 ——{ Ditto
I ' } Ditto, with veins of Quartz
K — 15 —— Elvane
L — 3 —— Killas
M — 7 —— Grouan Porphyry
N — i2 —— Elvane Quartz, granular and crystalline
O — 408 Killas
1270. Whole length of the tunnel.
The direction of all these beds seems to be parallel, and to range
nearly east and west.
All the veins that at present are known in the part of the hill
which the tunnel will intersect are shewn in the drawing, by lines,
which describe their dip as nearly as is ascertained from the little
that has as yet been seen of most of them.
Some of these lodes have been discovered by the tunnel, and
some are known by old works upon them near the surface.
It was not to be expected that any great proportion of the num-
ber would turn out productive of ore, or at least that they should
be so at the exact point where the tunnel cut them. One or two,
if rich in ore, might render the speculation a profitable one, and it
is rather extraordinary that the first which was discovered, at the
Tunnel of the Tavistock Canal. 153
commencement of the work at the north end, should be one of
that description. It is called Wheal Crebor lode, and has already
been worked about 60 fathoms deep under the level of the tunnel,
and has produced between 8 and 9000 tons of copper ore; its
direction is as usual from north-east to south-west, and it has been
traced to be the same vein that is worked at Wheal Crowndale mine
to the east, in killas ; and at Gunmis Lake mine to the west in granite;
at both of which concerns very large quantities of ore have been
raised. The lode at Wheal Crebor is in some places fourteen feet
wide, though in others not as many inches. It is traversed by cross
veins which /eave the lode, as the miners call it, a few feet.
The mine is now producing near 4000 tons of ore in the year:
a specimen will be found wiih the others. |
The next lode found in following the course of the tunnel south-
wards contained tin, but not in any great quantity, and very. little
work has been done upon it in the way of trial in consequence.
Further south is a lode called Wheal Georgiana, which has pro-
duced some rich copper ore in the porphyry, where the tunnel
discovered it. It has been pursued into the killas, but in this rock
it appears to be less productive of metal.
At the present end of this part of the work which is approaching
the centre of the hill, a vein has just been met with holding cop-
per, but too little is yet known of it to afford any description.*
In the space yet unopened between Bray’s shaft and the end
approaching it from the south, is a lode called Holming Bram,
which was formerly worked for tin, and on which considerable
expectation is grounded. Having simply stated the facts as far as
my knowledge of them goes, I abstain from speculating on the
* This vein underlies to the south, and is mentioned in a preceding note as an exception
to the usual dip of the lodes on this side of the hill.
154 Mr. TayLor’s description of the
support they may afford to any hypothesis on the formation of
the rocks or the veins, though they may offer some hints on the’
subject.
Imperfect as this sketch is, it may serve to lead the attention of
some more able member of the Society to the consideration of the
appearances of this district, which I thought sufficiently curious to’
encourage an attempt at their description.
POSTSCRIPT,
December, 1816.
I have lately visited the tunnel in consequence of its completion,
and therefore am enabled to complete the section of the hill, shew-
ing that no new strata have been discovered since the preceding
paper was written.
I have likewise ascertained more satisfactorily the dip or under-
lay of the lodes near the centre of the hill, and inserted them in
the section with two cross lodes or cross courses, which traverse
the lodes near that place. A remarkable alteration in the texture
of the killas occurs on each side of one of these cross courses, it is
found in such a decomposed state that it is converted into a soft
clayey matter, so as to be very difficult to preserve a passage through
until it can be securely arched.
A period of thirteen years has been occupied in bringing this
great work to a conclusion, and it has not been done without the
anxieties consequent on such an undertaking.
Two things of great importance in the practice of mining may
be remarked of this work. First, the extreme accuracy of the line
Tunnel of the Tavistock Canal, 155
of direction which has been preserved in so long a drift, although
the junctions were made from several different points.
Second, the small number of shafts, and consequently the length
of tunnel between each, which was ventilated during the progress
of the work. I am inclined to believe that it exceeds in this respect
all other attempts of a similar kind, and the section may therefore,
in the hands of the Geological Society, be a useful document for
future engineers. ‘The means which I adopted for obtaining per-
fect ventilation will be found to be described in the Transactions of
the Society for the Encouragement of Arts, Manufactures, and
Commerce, for the year 1810.
y
VIL. Corrections and Additions to the Sketch of the Mineralogy of Sky,
published in the third volume of the Transactions of the
Geological Soctety. io
‘8
By J. Mac Cursocn, M.D. F.L.S. President of the Geological Society,
Chemist to the Ordnance, Lecturer on Chemistry at the Royal
Military Academy, and Geologist to the Trigonometrical Survey.
{Read March 7th, 1817. ]
oe,
W HEN the Sketch of the Mineralogy of Sky was drawn up for
the Society’s volume in 1813,* I had no prospect of again visiting
that remote country. Circumstances having led me to traverse the
* The differences between the map of Sky which accompanies this supplementary paper,
and that formerly given, require some explanation, that the readers of the Geological
Transactions may be able to appreciate the reasons which have led to the alterations, and
account for those which, in a geological point of view, will be shown to be more apparent
than real, and to see what degree of confidence they may repose in the present one, —
In laying down the places of the different rocks, | formerly made use of the documents
from which Mr, Faden’s travelling map was constructed, and I was guided in the
nation by Mackenzie’s chart. The incorrectness of these has been the leading cause of
the apparent differences in the relative extent of the rocks as they have been delineated,
while their insufficiency for the purposes of a reticulum, arising from the great distortions
of the outline of the country and their deficiencies in its internal features, prevented me
from laying down many of the places where the existence or boundaries of particular rocks
had been accurately ascertained. Hence the geological delineation bore no proportion to
the accuracy of the observations, To these defects if there be added the blauks which
the partial nature of the former survey necessarily left, the discrepancies of the two will
not appear so considerable as they seem at first sight. I may also add, that it has been
found expedient to change the colours by which the different rocks are denoted ; another
apparent cause of difference.
For the present observations I have made use of Mr. Arrowsmith’s map, with certain
variations which I think it necessary to explain, that the degree of confidence to be Te
posed, whether in the original or in the alterations, may be understood,
Dr. MAc Cuttocn’s Supplement, ec. 157
same ground in much greater detail, I have been enabled to supply
the deficiencies which were acknowledged in that paper, and to
correct the errors into which I had unwarily fallen. I hold it my
A line drawn from the head of Loch Suizort to that of Loch Slapin will, under slight
exceptions, separate the estate of Lord Macdonald from those which lie to the westward
of it. It is not too much to say of the latter division that the outline of the coast is in-
correct, and the internal features something worse than conjectural. But the division
which constitutes Lord Macdonald’s estate, having been taken from a survey of that district
executed by an intelligent provincial surveyor for his Lordship, is deserving of considerable
confidence, and will be found over most parts sufficiently accurate in its internal features
for the purposes of the geological record. Even in the latter I have found it necessary to
make some additions and alterations; in the former part of the island these are consider-
able. I must however say, that even in this case I have limited the corrections to those
parts of the map where it was necessary to denote the boundaries of different rocks; the
northern parts, presenting only one substance, were not in immediate need of it, and I do
not pretend to arrange the geography of the island. It is necessary to point out the
alterations which have been made.
The region lying between Loch Eishort and the foot of the syenite hills, which includes
the valley of Strath, has been redrawn and reduced as far as was possible to the present
size, the intricacy of the position in the rocks which constitute it absolutely requiring a
more accurate detail of the leading features of the ground. Slight alterations have been
made in the shades which indicate the relative altitudes of the hills, wherever that was
called for, and the result will be apparent to those who shal) compare the present map
with Arrowsmith’s. At the point of Sleat and in the Kyle ri‘ch two or three alterations
have been made in the line of coast, these being absolutely required; others which might
have been made have been omitted, as they were not wanted for the particular objects of
this work,
The changes made on the eastern side are much more important. The estate of Strathaird
which includes Blaven and Coruisk, has been corrected from a private survey in possession
of the proprietor, Mr. Macalister. The Cuchullin hills are in the original map entirely
misplaced, while the remarkable lake above mentioned has been omitted. .These I have
rectified as far as was in my power, since both their form and extent were important. The
tract to the north of this including Mr. Macleod’s property, remains with very little
alteration, since its uniformity of composition did not call for any particular care.
The directions of the strata are marked by prolonged lines extending to the neighbour-
Ing shores or islands wherever they presented the same substances, and on these the
tendency as well as the quantity of the dip is occasionally pointed out by an appropriate
index and numbers, wherever it seemed necessary to specify them.
Finally, whatever corrections may be found in this map are merely intended to serve the
purpose of this paper; the formation oft correct map of Sky must yet be considered a
work far distant.
VOL. Iv. x
158 Dr. Mac CuLiocu’s Supplement to the
duty to supply the one and to correct the other ; and consider that
an acknowledgment of the latter is the greatest mark of respect I
can pay to that body under whose protection they were laid
before the readers of its Transactions. '
No apology can be offered for want of industry ; but the extent
of this island, the difficulty of traversing it, and the intricate dis-
position of its rocks, offer some excuse for deficiencies, where want
of time was further superadded to all other obstacles. For errors
there is no excuse, but in correcting them it will not be useless to
point out the causes from which they arose, since other observers
may take warning from them, and learn to mistrust all observations
which are not founded on rigid investigation, free from conjecture,
and free from system.
To conclude respecting what is, from that which ought to be,
will lead, as it has already led, to greater errors than those which
I shall have to record. Equal hazard arises from judging of the
structure of a district by the examination of specimens only. In
rocks the specimen is not always an abstract of the geological
nature of the series in which it occurs, and the mistakes which have
here arisen from this cause will be equally apparent with those
which have resulted from the preceding one. The last source of
error which I shall notice was the imperfection of the outline of
the island as it is given in Mackenzies chart by which I was
guided. Here, among other similar errors, the distance between
the head of Loch in daal and that of Loch Eishort, which scarcely
exceeds a mile and a half, is marked at five miles. Hence, finding
my observations to disagree with the map on which I attempted to
record them, I abandoned altogether a pursuit which, had I con-
tinued it, would have led me at that time, as it has since done, to
determine the sandstone series to a much greater extent than I then
imagined it to occupy.
Mineralogy of Sky. FR
The most leading error is that which states the promontory of
Sleat as composed of micaceous schistus. This substance occurs
in several places, and often in distinct beds of considerable thickness,
while in others it consists of mere lamine interposed among the
other rocks. These rocks are of very various composition, but as
gneiss occurs in considerable quantity among them, exceeding
greatly the space occupied by the micaceous schist, the latter will
probably be considered by most geologists as subordinate to the
former, and the gneiss as being the lowest and fundamental rock
of Sky. But the truth is, that this series is not amenable to any
systematic rules, and it will be better to state the fact as it exists,
than to incur the risk of a similar error by transferring to gneiss
that rank which I had before conferred on micaceous schist. It
will be seen that the series presents anomalies which cannot be
removed by any theory of subordination, and that the history of
the district of Sleat is not' the least interesting part of the unex-
pected appearances presented by this very instructive island.
The characters of the gneiss are so strongly marked in one part
of the space which it occupies, that there can be no difference of
opinion respecting it. Besides mica or hornblende it contains a
conspicuous proportion of high red felspar and quartz, being at the
same time distinctly laminated, and from the contrast of its colours,
very remarkable.
From this regularity of structure and composition it passes into
a substance for which there is no name in the present nomenclature
of rocks, and which can only be ranked with gneiss by assuming a
considerable latitude of character. This rock is a compound of
felspar and quartz with chlorite schist, these substances being still
interlaminated as before, so that each mineral generally occupies a
distinct portion of the specimen, the latter becoming substituted
x2
160 Dr. Mac Cuxtocu’s Supplement to the
for the mica that characterizes the regular varieties. By degrees
the chlorite schist becomes predominant, and at length the felspar
is excluded, so that all appearance of gneiss ceases and a simple
series of chlorite schist remains. I suppress a detail of the endless
varieties found through this series, as such substances can rarely be
rendered intelligible in description. But I may add that hornblende
schist, so generally found to accompany gneiss, alternates here also
with it under many different aspects.
With respect to the position and boundaries of this series, it is
found occupying beds of which the elevated edges present a rec-
tilinear direction towards the north-east, dipping to the eastward
in an angle which varies between 30 and 50 degrees. Its boundary
towards the west lies near the small island Oransa, where it is
succeeded immediately by the graywacké schist and the accom-
panying quartz rock or hard sandstone which were described in
the original paper, but which I shall presently describe again in
greater detai!, having had an opportunity of verifying much of that
which was only conjectural, and of extending its limits to a much
greater distance than I had foreseen.
Although the boundary of this series, in which gneiss and
chlorite slate form the principal parts, is thus defined at the northern
end of its western side, no such decided change is perceived at the
southern end of the same line, which, if protracted from the place
first mentioned near Isle Oransa, would cut a point on the western
side of Sleat. The interior of the country is too much encumbered
with peat and with vegetation to permit of any decision on a
subject so obscure as is the point of change between the gneiss
Series and the rocks which follow it, and I must therefore limit
myself to the appearances which occur on the sea shore, where
every change can be traced in the most minute manner. Here
Mineralogy of Sky. 161
there will be found a transition, unexpected and improbable as it
may at first seem, between the two series, that of the gneiss, and
that of the graywacké and sandstone which follows it; but at what
point between the two extremities of the gneiss boundary a decided
change takes the place of a gradual transition it will be for ever
impossible satisfactorily to determine. I must add that the limit of
the gneiss series on the eastern side of Sleat is the sea shore itself.
I must now proceed, before entering further on the transition of
the gneiss series, to describe that which in the original paper I
called the series of blue quartz rock and schist, in which there is
somewhat to amend and somewhat to supply. With this I must
here include the red sandstone, formerly separated from the other
two rocks on the same systematical views which led into the other
errors already mentioned. ‘The conclusions then drawn were suf-
ficiently justified by the partial view of the country which I had at
that time obtained, but they were founded on observations too
limited. A more complete investigation, with a greater disregard
of theoretic views, would not only have led to sounder conclusions,
but have removed many difficulties which I encountered both in
the examination and in the attempt to reconcile discordant phe-
nomena.
Although on reviewing the places I examined before, I find the
description formerly given of these substances locally correct, and
the conjecture I had formed of the nature of the rocks toward the
Kyle ri‘ch equally so, yet an examination of additional parts of this
series renders it necessary to remodel the whole description, as it
possesses a degree of intricacy which it was impossible to suspect,
and which nothing but a very accurate examination could ever
have induced me to credit, since it is at variance with the usual
phenomena that attend these rocks.
162 Dr. Mac CuLLocn’s Supplement to the
The whole series presents from one end to the other a repetition
of the same parts, although the several substances are in different
places differently proportioned, the one exceeding in one place,
while in another a different member of the series will be found
predominant. One exception to this rule will afterwards be
noticed.
The rocks which compose the series are the following.
Red sandstone, more or less indurated, of which the general
characters were formerly described.
Quartz rock, or, as some may prefer to name it, indurated sand-
stone, passing from lead blue to grey and brown, sometimes pure,
at others containing felspar.
Schist, which is sometimes not to be distinguished from ordinary
clay slate, and at other times contains particles of quartz and mica.
If one term is to be used for the whole it must probably be called
graywacke schist.
White compact quartz rock: this substance is found only in one
part of the series.
In the original paper I described the red sandstone as following
the blue rock and schist in conformable order, which it in fact does
throughout a considerable tract without any repetition of the two
latter. But on pursuing these beds further than I then did, whether
backwards or forwards, according to their relative inferiority or
superiority, repeated alternations of all those substances occur.
The dip which I also described as constant and westerly, is only
thus regular from that part of Loch Eishort whence my exami-
nation at that time commenced, to its upper portions, ascending
according to the order of the beds. In tracing from that point
towards the last, or downwards according to the order of the beds,
through those parts of the country respecting which I formerly
Mineralogy of Sky. 163
offered only conjectures on the similarity of the series, I do not find
those conjectures verified ; the position of the beds becoming first
vertical and then reversed and irregular; ultimately settling in a
dip towards the east, the reverse of that which predominates on the
western or upper side of the series. But whatever irregularities
are found in the dip, there are none in the direction, which with a
slight local disturbance near Ord is invariably rectilinear, and on
the north-east line or nearly so.
On the north-eastern end of this series, where it forms the
mountains of the Kyle, the rocks can be traced perfectly from the
gneiss at Isle Oransa to the commencement of the limestone near
Broadford, this space comprising the collective thickness of the
strata ; but through this tract the quartz rock or indurated sandstone
is predominant. If these strata are prolonged toward the south-
west their characters change, or they are discontinuous in com-
position according to the line of their direction, since the schist and
quartz rock are most abundant toward the north-eastern end, while
red sandstone prevails at the opposite one.
The space which they have been represented to occupy on the
original map must also be extended, and to a certain degree this
may be done by prolonging the line of direction from that point
near Isle Oransa where the junction of the gneiss is found.
I have already related the error committed by allowing too much
space to the micaceous schist, which occurs only as one of the
members of a series principally formed of gneiss and chlorite schist.
Another of the sources of that error will now appear when I
describe the last enumerated member of the red sandstone series ;
and it will no less excite surprise than operate as a caution in the
present state of geological science, against judging of rocks by
analogies, or by any other evidence than that of actual and careful
examination.
164 Dr. Mac Cutiocn’s Supplement to the
Meeting near Loch Eishort with the white compact quartz rock
which was described in the original paper, I concluded that here,
as elsewhere, it was a member of the primary rocks, and therefore
without hesitation laid it down among the series which I considered
to be micaceous schist, concluding also that I had in reaching it
arrived at the bottom of that series which contained the blue quartz
rock and schist. That white quartz is however a member of this
very series, holding a parallel course with it, and being preceded
as it is followed by red sandstone, blue quartz rock, and graywacke
schist. This circumstance forms a material addition to the history
of quartz rock, and an alteration no less material in that of the
series to which the red sandstone belongs.
I must here remark that in calling so complicated a series of rocks
by the title of only one of its members, the red sandstone, I have
done so only on account of the necessity of using one term for the
temporary purpose of a geological description, and that this one
was chosen from the predominance of that substance. I can only
add that this predominant member corresponds in mineral character
with the other red sandstones which in Scotland occupy the inter-
mediate place between the primary rocks and the secondary strata
containing organic remains, and that it is connected by visible
indications with many similar portions of the same rock to be
found not only in Sky but in the neighbouring islands. As it is
also followed in a conformable order by the limestone series for-
merly described, it possesses anothet common character with the
usual red sandstone of other districts. If any person shall think
that the whole of this series should be ranked under graywacké
and called a ¢ransition series, I can have no objection, but am at the
same time unable to see what advantage is gained by the substitu~
tion, or in what respect the science is aided by it; while at the
same time the red sandstone will be as much transferred from its
Mineralogy of Sky. 165
usual place in the one case as the graywacké is in the other. But
the island of Sky is very often unsystematical: that which follows
perhaps still more so than that which has preceded.
In attempting to trace the red sandstone below, or rather beyond
the white quartz rock, it is not found to terminate on the north-
western shore of Sleat, at the place where, according to the line of
direction prolonged from Isle Oransa, it should end. Instead of
that, the alternations of sandstone and schist continue. Gradually
however they increase in frequency, and becoming at length undu-
lated and contorted, they cannot at a distance be distinguished from
gneiss in their general aspect and disposition. In examining the
substances, the first alteration perceived is the gradual induration
of the sandstone, which becomes first a compact quartz containing
grains of red felspar. At length the felspar acquires a laminar
tendency, the schist still remaining unchanged, the rock thus
becoming an irregular gneiss (if it may be so called) consisting of
laminz of quartz, felspar and graywacké schist. Approaching the
point of Sleat the schist gradually becomes green and glossy, thus
passing into chlorite slate, and here we arrive by an insensible
gradation to the variety of gneiss which I formerly described as
found there. In thus pursuing the red sandstone on the western
side of Sleat, the reason appears why I could not when speaking of
that rock, define the boundary of the gneiss on this side of the
island, and I need now scarcely repeat, that any attempt to examine
rocks so constituted, in the mterior country, would leave nothing
but doubt and uncertainty; for which reason I have limited the
description to the sea coast, where every foot of the rock through
all its transitions admits of free examination.
I have no commentary to offer on these facts, which seem cal-
culated, if not to excite disbelief, at least to set our present systems
VOL. Iv. wow! |
166 Dr. Mac Curtocn’s Supplement to the
at some defiance. It is possible to reconcile them only by supposing
that the red sandstone series belongs to the primary rocks, and the
whole of these strata which extend from the point of Sleat to the
limestone of Strath, will thus form a succession of rocks alternating
with and graduating into each other. That the gneiss is a primary
rock can, I imagine, admit of no dispute.
In formerly describing the limestone district, I expressed my
expectation that the strata of Kilbride and those at the entrance of
Loch Eishort would be found identical with those at Broadford,
and that expectation has been realized by a complete examination
of the district in question. .
On the Broadford shore the commencement of the limestone
beds is found near a small farm called Lucy, but their actual contact
with the sandstone cannot be seen, on account of a sandy beach
‘which covers the junction. It is probable that some conglomerate
exists in this interval, as detached masses of such a rock are found
in different places-in the hilly grounds between Strath and Loch
Eishort ; but I need not dwell on a circumstance so common every
where that it can scarcely fail to be present here. As the inclinations
of the sandstone and limestone are in the same direction near this
junction, the latter however dipping only five degrees to the north-
west while the former dips ten, there can be no doubt but that they
are connected in the usual regular order of succession.
From this, which I shall call the lowest line of the limestone, it
can be traced under various interruptions along a high ridge of
hills to Loch Eishort, where it coincides with the ‘beds formerly
described as found there. Independently of this connection, the
identity of the whole is proved by the correspondence of the or-
ganic remains, which at Broadford however are more abundant
than on the opposite side. The principal difference at the two ex-
tremities consists in the numerous beds of shale and sandstone: that
Mineralogy of Sky. 167
alternate with the limestone strata on the Broadford side, and in
the inferior solidity and thickness of the calcareous beds; while at
the same time the harder schist, which divides them on the south-
western shore, is absent, the one appearing to be a substitute for
the other. The shale is a mixture of black clay, sand, and mica,
thickly and imperfectly fissile, and the sandstone which is of dif-
ferent colours, but generally brownish, contains much clay and
calcareous earth, the organic remains being found in each of these
beds just as they are in the limestone.
~The interruptions, to which I have here alluded, that prevent
us from tracing the limestone over the hills that bound the southern
side of Strath, arise partly from the boggy and covered nature of
the ground, and partly from the intrusion of a hill of syenite,
which extends far from the portion formerly noticed, towards
Broadford, and which can in many places be distinctly traced
overlying the limestone, shale, or sandstone, as either of these
happens to be present at the point where the contact is exposed.
There is no satisfactory evidence to be procured here of that change
from the stratified to the unstratified limestone which I have de-
scribed in the original paper, since there is no situation, where the
contact of the two can be precisely traced. Yet there is even here
sufficient evidence to give rise to such a suspicion, and more than
enough to confirm the observations formerly recorded, and to
justify the conclusions deduced from them. ‘To enter into further
details on this subject would now be superfluous, as the feebler
evidence is of little value where the stronger has preceded. I shall
only add, that beds of ordinary quartz are in one place found
regularly interstratified with the marble limestone, as if the power
which had converted the common limestone into this one, had also
changed the sandstone into quartz: and that many gradations by
WD box &
168 Dr. Mac Curtocn’s Supplement to the
which the ordinary limestone appears to pass into the marble, can
also be traced, although in consequence of the irregular nature of
the ground they are widely dispersed. I ought also to add that in
one of these intermediate portions I found layers and scattered spe-
cimens of bodies having the general aspect of those obscurely
organized fossils which have been all confounded under the name
of alcyonia, consisting of a calcareous carbonate whiter than the
surrounding rock, their surfaces being covered with minute but
irregular crystals of the same substance, and being so much more
durable than the surrounding materials as to remain protruding
after these have been washed away.
To the topographic detail as given in the original paper, I must
now also make an addition, the nature of which will be better
understood by inspecting the improved map.
The strata on the Broadford shore may be traced to a place
opposite Scalpa, but without a name, where they terminate in a
succession of beds consisting of the shale only. After some inter-
ruption, in consequence of the intrusion of a mass of syenite and
trap, a small patch of irregular limestone is seen, which soon ceases
in consequence of the renewal of the syenite, not to appear again
till we arrive at Loch Sligachan.
On this shore the overlying position of the syenite can be easily
traced at the places of contact, demonstrating that it here combines |
the same double relation to the stratified secondary rocks which it
is found to bear elsewhere ; cutting through them at the same time
that it covers them.
The boundary between the upper portions, or the north-western
line of the Strath limestone and the syenite, is extremely irregular,
although it is not often possible to procure a sight of the actual
contact, or even of the probable junction of these different rocks.
It is however a sufficient proof of that irregularity, that as marble
Mineralogy of Sky. 169
is found at the foot of the ascent of Ben-na-caillich, so syenite
abounds on the opposite side of the valley, while every where
throughout it patches of the latter rock, often of very small extent,
are found surrounded on all sides by limestone.
I must further add to the description of the limestone that
pectines of considerable size are found among its upper beds, to-
gether with terebratulz, and numerous fragments of shells of which
some resemble portions of mytili, but the whole in too imperfect a
state to admit of accurate examination.
The description of the limestone of Sligachan having in the
original paper been left imperfect, I may now add to it the follow-
ing particulars. Beds of the stratified limestone and shale, succeeding
a narrow portion of the red sandstone, and precisely resembling
the strata of Broadford, extend from the portions of irregular lime-
stone before mentioned to the shore of the loch. These also dip
to the north-west, but at a considerable angle, and the direction of
their elevated edges, like that of all the regular rocks of Sky, is to
the north-east, or thereabouts. It is evident that this limestone is
a portion of the same series which occupies Strath, the intermediate
parts having been either displaced or overwhelmed by the syenite.
The circumstance of greatest difficulty in comparing these two
portions of limestone, is the intervention of the red sandstone, in
conformable position, and therefore apparently alternating with
them, since the angle of inclination has in all the same tendency.
It is not easy to admit of this alternation consistently with what we
know of the relative positions of the red sandstone with limestone
of this character in other places. Unfortunately Sky itself offers no
clue by which we can trace this connection more intimately, or
on which we could found some theory of it less at variance with
ordinary experience. Whatever the nature of this difficulty may
be, I must for the present suffer it to remain unexplained, since
170 Dr. Mac Cuttocn’s Supplement to the
without detailing the history of all the islands in the vicinity
which partake of and elucidate the structure of Sky, no adequate
conjecture can be offered respecting it. There is here no room for
such a description, but I hope on some future occasion to give a
collective view of the whole group, and thus to render the geo-
logical history of the principal island less incomplete than 1 am
still compelled to leave it. The connections of the western islands
with each other and with the main land are so intimate, and the
light obtained from one portion is so necessary for the elucidation
of others, that the separate description of any individual of the
group must always be imperfect.
The account of the limestone which is found near Ord on the
southern shore of Loch Eishort was in the original paper imperfect,
as well in respect to its topography as its mineralogical description.
It occupies a small hill which includes the house of Ord, and is
singularly irregular in its position, as well with respect to its own ar-
rangement, as to its connection with the neighbouring rocks, among
which, as I have already shown, there occurs a great degree of con-
fusion. Notwithstanding this irregularity, a careful and close in-
vestigation of it will leave no doubt respecting the superiority of
its position to the sandstone with which it is associated, and how-
ever widely separated from the more regular beds on the opposed =
shore, there is no want of indications to prove that it forms a por-
tion of the limestone of Strath; its present confusion appearing,
like that of the neighbouring sandstone, to have arisen from some
common cause acting on both, to which also we may perhaps at-
tribute the peculiarities which its structure and composition pre-
sent. Its stratification is in general sufficiently apparent on the
great scale, although in the more detached portions often invisible,
Mineralogy of Sky. 171
in which respect it possesses a resemblance to the marble limestone
formerly described. But I need not detail those peculiarities of
structure which can scarcely be rendered intelligible by words.
That which is most remarkable is the large quantity of siliceous
matter it contains. ‘This is found dispersed through it in irregular
nodules, often scarcely differing from common flint, or rather
resembling that variety of chert which in other situations is found
in limestones. These nodules are white, grey and mottled, in some
places of an obscure pale red, and they are so predominant in a
few situations as nearly to exclude altogether the calcareous matter.
In the original paper I represented the sandstone of Strathaird as
a portion of a series superior to the limestone of Strath, and a sub-
sequent and more extensive examination of the country enables me
to confirm this view. But I may add to it the following remark,
which is not unworthy ef notice. ‘The trap veins which form so
conspicuous a feature on the eastern side of this promontory are
crowded together in the manner already described only along a
certain, though by far the greatest, portion of the shore. At the
extremity of the promontory they are rare, and are scarcely found
on the western side. ‘They appear indeed to be connected with
the body of the trap which was described as covering the stratified
rocks, and to be ramifications or processes from that mass. On
the western side, and at the point of Aird, where they are rare or
altogether wanting, the strata cons'st of a soft white calcareous
sandstone, and are nevertheless apparently continuous with the
hard ones formerly described as occurring where the trap veins
predominate; while the identity is still further marked by the cor-
respondence of the same complicated schistose structure, that struc-
ture being even more apparent in the:softer rocks, as more readily
17Z Dr. Mac Cutrocn’s Supplement to the
yielding to the action of the elements. I remarked formerly that
these strata, however separated in position, were analogous to the
white sandstone which occurs at Portree and elsewhere in the
north-eastern portion of Sky, and is accompanied by limestone,
shale, and coal. Having then but little acquaintance with that
part of the island, the description of these strata was avowedly left
imperfect, and it is now necessary to supply the deficiency.
As I remarked not long ago that a description of the neighbouring
islands was requisite to throw light on the obscure connection uf
the red sandstone with the limestones of Strath and of Sligachan,
so I may here repeat that the history of the uppermost strata of
Sky, which I now propose to sketch, would be materially elu-
cidated by that of Rasay. But as the description of this island
would be here inadmissible, I can only ‘say generally, that the
deficiencies of connection which occur in Sky, and which compel
me on many occasions to have recourse to inference and analogy,
are in a great measure supplied by the structure of that island,
which, while it is more continuous and accessible, is at the same
time such as to leave no doubt respecting the identity of strata
separated at present by a narrow arm of the sea.
It has been seen that as the gryphite limestone immediately fol-
lows the red sandstone, so it is succeeded by the calcareous white
and grey sandstone of Strathaird. The same succession may be
traced in a more circuitous manner by comparing the strata of
Sligachan, Scalpa, and Rasay. But it is apparent on considering
the map of Sky, that the portion of these uppermost strata which
occupies the district of Trotternish is separated from the gryphite
limestone by an interval, partly the result of the direction of the
shores, and partly produced by the intervening mass of trap and
syenite. There is no actual contact of the two to be seen, but the
Mineralogy of Sky. 173
nearest indication of a connection between them is to be found at
Loch Sligachan. I have already described the Jimestone which oc-
curs on the southern shore of this inlet. On its northern side there
are seen a few beds of white, brown, and black sandstone, separated
from that limestone by the breadth of the loch only, but lying in
a regular order conformable to it, and doubtless connected with it
under the depths of the sea. These are immediately cut off by a
mass of trap, which extends without interruption for nearly two
miles along the shore, thus depriving us of all means of tracing
any connection between them and the next stratified rock. That
rock appears at Conurdan, occupying a low situation on the sea
shore, in a thin series of nearly horizontal but somewhat irregular
beds surrounded on all sides by trap, These beds consist of a
brown calcareo-argillacedus sandstone, similar to one of the beds
at Loch Sligachan, and characterized by the spheroidal concretions
which prevail through the greater part of the sandstone of this dis-
trict. After an interval of trap the same sandstone re-appears as
we approach Portree, but still scarcely visible except in the natural
sections of the shore, since the whole interior surface of the land
is covered by the superincumbent trap, which conceals the struc-
ture of this country from the most watchful eye. Here it imme-
diately presents a collection of beds of enormous thickness rising
into lofty cliffs, which, although inaccessible, may be approached
in favourable weather so near from the sea as to leave no doubt
respecting their nature. This is the hill of Camiskianevig which
forms the southern side of Portree harbour.
The mass of trap which overlies these strata cuts through them
in the interior of the harbour, and thus forms another interruption
between them and the corresponding ones, which again appear with
similar dimensions on the northern side of the harbour. From this
VoL. IV. Z
174 Dr. Mac CuLiocu’s Supplement to the
place they continue to form high cliffs, covered in a similar man-
ner by trap, and extending along the coast for a considerable space
towards Holme. Limestone occurs together with the sandstone
in the interval last described, but the shore is so difficult of access
on account of its rocky boundary, the want of creeks or harbours
where a boat may land, and the general prevalence of a heavy sea,
that it is not possible to trace every point, nor, consequently, to
perceive where the changes of the strata take place; while, from
the mural front and excessive height of the cliffs, they are them-
selves absolutely inaccessible. To add to the difficulty, the lime-
stone when weathered puts on the grey colour and aspect of the
sandstone so perfectly, that it is often difficult to distinguish them,
when even within reach, without the assistance of a recent fracture,
I must here premise that the whole of the strata hereafter to be
described, as well as those new mentioned, have a regular and even
dip towards the north-west, which is at a small angle, although no
opportunity is offered of ascertaining its quantity. In this respect they
are conformable, if they are not absolutely consecutive, to the Strath
-limestone, and I may add that this dip is apparent over the interior
country wherever they can be seen, while at the same time it is
indicated generally by the gradual disappearance of the lower beds
on the west side of the promontory, their thickness amounting on
that shore to a few feet only, while on the east side it reaches to
many hundreds. I need scarcely say that cases of obvious disturb-
ance connected with the interference of trap must be excepted from
this general rule.
Passing Holme the shore becomes occasionally more easy of ac-
cess, although the mural line of cliff continues, and here limestone
strata are found to have succeeded to the sandstone. These strata
contain spheroidal concretions similar to those which attend the
Mineralogy of Sky. 175
sandstone, and which increase the difficulty of distinguishing be-
tween the two substances at that distance from which alone they
are visible. Hence it is with some doubt that I must speak of the
absolute nature of the whole strata between Portree and Holme;
a matter fortunately of no serious moment, as geologists are well
aware of the intimate connection subsisting between these strata,
which have been fully examined and described in many parts of
the British islands.
Alternations of micaceous shale and of brown sandstone are
found in the calcareous beds, of which the colour and composition
vary materially, although the predominant colour is smoke-grey,
the aspect earthy, and the composition argillaceous. The only
organic remains which I could find among them were a large am-
monite and a belemnite often exceeding a foot in length. As far
as I can discover, our conchologists have not yet ascertained these
species or distinguished them by specific names.
But it is unnecessary to enter into minute details respecting this
limestone, since it must be already seen that it belongs to the lias,
a rock well known to geologists, and already often described under
all its varieties of aspect.
I shall take some future opportunity of describing this important
series as it occurs throughout the western islands, since it is so dis-
persed as to involve the history of many of them, and to render it
impossible to give an adequate account of it in a paper so local as
this.
Proceeding northwards along this shore, it appears that the beds
which follow are superior in position to the preceding. This
should result from their general dip, but it cannot be distinctly
ascertained. Here, common shale begins to appear in alternation
with the other substances, and the quantity of siliceous schistus
Z2
176 Dr. Mac Currocn’s Supplement to the
strewed on the shore proves that this substance also exists some-
where in the cliffs; doubtless under the same circumstances which
I formerly described at Duntulm. I must add that the specimens
sometimes contain shells, and that, resembling basalt in appearance
and texture, they confirm the truth of those suspicions respecting
the asserted existence of organic substances in that rock, which it
is here sufficient to have mentioned.
Together with these detached blocks of siliceous schist are found
similar fragments of a cherty substance, extremely hard and brittle,
and breaking into acute conchoidal fragments, but possessing an
earthy aspect. Its colours vary from greyish white to dark smoke-
grey, and I may add that its degrees of induration are also various.
Occasionally, portions of the siliceous schist are attached to it, the
separation being marked by well defined planes, and, from the
contrast of colour, very conspicuous. If there were any doubt that
this chert was originally a portion of the lias indurated by the same
process that has converted the shale into siliceous schist, it would
be removed by the fact that on the western shore of this district
the two substances are found zz sztu, associated in the same manner
and in various states of transition from common lias and shale to
chert and siliceous schist. .
The last portions of limestone to be seen on this shore occur at
the island of Fladda, occupying a very low position, and at length
disappearing gradually below the trap, which beyond this point
forms the whole coast as far as Duntulm, constituting also the
islands of Trodda and Fladdahuna, as well as the various picturesque
rocks which are scattered to the north of the point of Hunish.
This bed of limestone abounds in organic remains, but so condensed
together, and so broken, as to present no specimens capable of being
ascertained: they resemble fragments of some sort of cockle and of
anomiz, or perhaps ostrez.
Mineralogy of Sky. i a
If we proceed to the western side of this promontory for the
purpose of recovering these strata, we find them at Duntulm, from
which place they extend interruptedly for a few miles along this
shore, when they finally disappear. ‘The same organic remains,
the same shale, the same limestone, calcareous sandstone, and sili-
ceous schist, mark the identity of these with the strata on the
eastern side, an identity still further confirmed by the prevailing
correspondence of their inclinations. I may at the same time add
that a greater facility of access to the upper beds, the only ones here
to be found, assists us in obtaining a more correct notion of those
beds which from their elevation above the shore are inaccessible on
the east side, and that we thus become acquainted with those nu-
merous varieties of the lias limestone, which having often been
described by geologists, serve to confirm the nature of these last and
uppermost of the stratified rocks of Sky. The nature and origin
of siliceous schistus can here also be traced in many other places
besides that most conspicuous one at Duntulm which I formerly
described ; and so many gradations between that rock and shale are
to be observed that the most satisfactory evidence of their connec-
tion can be obtained.
From a comparison of these several facts, the details of which
I have from the nature of this supplementary paper thought it
necessary to condense, it is apparent that the fundamental rocks of
the district of Trotternish, are those secondary and stratified sub-
stances which are connected with the lias formation, and that these
are. both surmounted and intersected by trap. If but little additio-
nal evidence of this view can be obtained from an examination
of the interior country, that little is at least satisfactory. The
same substances occur in numerous places, where precipitous faces
or the sections formed by rivers expose the rocks that lie beneath
178 Dr. Mac CuLtocn’s Supplement to the
the trap. If they are disjointed in position, or if they appear pro-
miscuously scattered, they still retain their natural connection,
while the identity of their mineral structure is every where con-
sistent. In one place only some strata of a quartz rock are to be
seen, which might lead us to hesitate did we not recollect that
in other instances the same causes which have converted shale into
siliceous schist have also been found to change sandstone into quartz.
The same causes which formerly prevented me from examining
the strata of Trotternish, the deficiency of which I have now sup-
plied, also impeded the investigation of the coal which is connected
with them. Although I have since followed and traced the appear-
ances of this mineral in those places where it has been observed,
there is but little satisfactory information to be obtained respecting
it. The cause of this obscurity is easily understood. It has been
remarked that although the basis of this promontory consists of the
stratified rocks which have been just described, the whole is sur-
mounted and intersected by trap. The decomposition of this rock,
and that of the softer-strata which lie beneath, have moreover
covered the whole country with a deep soil, which from its fertility
tends further to conceal the nature of the rocks on which it reposes.
Hence it is only in the casual exposure of some jutting rock or
broken face, some denuded acclivity or bed of a stream, that any
access can be procured to the stratified substances, and from this
cause it is rarely, if ever, possible to trace the relations of the par-
ticular stratum which comes into view. It is among such dispersed
portions of strata that the appearances of coal are observed. They
are not unfrequent, but are always extremely scanty, both in their
thickness and in their apparent horizontal extent, since the strata
which contain them are every where cut off by veins or by masses
of trap. They are interposed, as we might expect, among the
Mineralogy of Sky. P79
shale and sandstone, and, as we may conclude from the general
bearings of the strata already described, occupy the upper beds of
this formation. It is impossible to say that they do not exist at a
greater depth, since the inferior strata, as I have already shown,
can scarcely be considered sufficiently accessible to enable us to
determine on the absence of a substance of which the thickness does
not exceed a very few inches. Nevertheless, no indications of coal
can be perceived along the eastern line of cliffs, where the deeper
strata are exposed, and we may therefore for the present conclude
that they lie above the lias and its associated sandstone, or at least
among its uppermost beds. It can serve no purpose to enumerate
the places where these indications of coal have been observed, since
they cannot be verified on the map, and are indeed generally
nameless. As the strata rarely exceed an inch in thickness, it is
equally evident that those which are visible are worthless in an
economical view, while the certainty of a speedy interruption from
the intrusion of trap removes all temptation to penetrate to greater
depths, or to expend capital in a more effectual research.
While on the subject of coal, I may add to the former account,
that I have observed portions of wood coal in more places than
those originally enumerated, but they are no where of sufficient
importance, or marked by any such peculiarities as to require
further description.
In describing the several trap rocks of Sky, I am sensible of
having often spoken generally, when the circumstances might per-
haps have admitted of more accurate details. The cause of this
however is principally to be sought in the imperfect acquaintance
which geologists still possess with this infinitely varied and obscure
class of rocks, an obscurity which increased experience is daily
180 Dr. Mac Cutrocn’s Supplement to the
tending to remove. Repeated and careful examination of them
as they occur in the western islands, have, since the time at which
the original paper on Sky was drawn up, enabled me considerably
to amend their history, and to dispose of them in a more exact
and connected manner ; but as the detail would here be inadmissi-
ble, from the length of discussion to which it would lead, I shall
make no attempt to improve the former imperfect remarks, but re~
serve that which might be here added, for some future communi-
cation. I shall however attempt to amend one or two of the des-
criptions contained in the former paper, where I had been obliged
to rely on a distant view, and was therefore compelled to speak
only in the most general terms.
The first of these portions of trap is that which occupies the
district of Trotternish, of which, as well as of the stratified sub-
stances but just described, I had formerly an opportunity of forms
ing only a very superficial notion.
As I have just shewn, it both intersects and surmounts the se-
condary strata, while in many places it appears also to be horizon-
tally or conformably interstratified with them. These interferences
are very remarkable, and exhibited on a scale of such extent as to
include every circumstance which has yet been described on the
subject of their junctions. But without numerous drawings no
adequate idea of them can be conveyed, and as there is little to be
said respecting them which would not be a repetition of the remarks
which have on numerous occasions been made on similar appear-
ances, I shall forbear to enter into details respecting them. I
shall only observe, that all these irregularities occur in a mass,
which taken in a general view, has the character of a strati-
fied trap, since notwithstanding them it bears a strong parallelism
to the already parallel strata with which it is associated. It is abun-
Mineralogy of Sky. 181
dantly plain that the appearance of stratification in the trap is here
the result of the form of the rocks on which it is placed, or among
which it has intruded, in the former case surmounting them, and
in the latter appearing to alternate with them. The instances of
this apparent alternation are highly interesting, from their great
extent, as well as from the perfect conviction which they present of
the fallacious nature of this supposed connection. In many cases
the alternations of the trap are as regular, as decided, and as evenly
parallel, as those of the stratified rocks themselves, the sandstone
and limestone among which it lies. Yet in no instance does it
not happen, but that at some point or other the alternating bed of
trap will detach an intersecting vein, unite itself to the superin-
cumbent mass, or, quitting the interval between two given beds of
limestone or sandstone, make its way across the one immediately
above or below, and then proceed with a regularity as great, for
another long space, between some other pair of proximate strata. In
one or more instances I have observed this to happen after more
than a mile in extent, throughout all which space not the minutest
irregularity had appeared to indicate any thing else than a perfectly
conformable and alternating stratification. I have no doubt that,
could such extensive exposure be oftener procured, all the instances
of supposed alternation between the trap rocks and the stratified
ones would prove similar to these.
With respect to the trap itself it is most generally amorphous. As
we approach however towards the northern end of the promontory
it becomes columnar, and this character prevails round the points of
Aird and Hunish beyond Duntulm, where it at length terminates.
Although the columns are formed on a large scale, and are indivi-
dually rude and imperfectly defined, yet their picturesque effect,
when seen from a point of view where they can be properly com-
VoL. Iv. aha
182 Dr. Mac Cuitocn’s Supplement to the
prehended as a whole, is not less symmetrical than that of the faces
of Staffa, while at the same time they far exceed it in grandeur as
well as in absolute magnitude. Their height reaches from 200 to
300 feet and upwards, a dimension, however large, not sufficient to
overpower the due proportion which should exist between the
aggregate structure and the parts of which it is composed, since the
magnitude of the columns is proportioned to their height, and the
total effect therefore similar to that of Staffa, where the proportions
are so nicely adapted for beauty.
With respect to the composition of this variety of trap, there is
necessarily some uncertainty, since the great extent of it, as well as
the inaccessible nature of most parts, renders it utterly impossible
to examine it throughout. We also know that the various mem-
bers of this family are often found irregularly intermixed, so that
to have ascertained the composition of one portion of a mass, gives
us no assurance that we have made ourselves acquainted with that
of the whole. Yet I am inclined to think that the greater part
will be found to consist of a substance analogous to greenstone,
in which augit occupies the place of hornblende, a rock of great
frequency in Scotland, and often, perhaps generally hitherto con-
founded with common greenstone, unless in a few such remark-
able cases as that of Rum, where the substances are too distinct to
admit of mistake. It may be called augit rock, without introducing
any confusion into mineralogical nomenclature.
For the sake of topography I must here mention a small mass of
trap, lying on a part of the coast of Sleat not easily visited, and
omitted in the original paper. It occupies a projecting point south
of Talivil, where its place has been marked in the amended map.
It covers a space of about a mile in extent, lying over the red
sandstone. It is rudely columnar and slightly porphyritic, and
Mineralogy of Sky. 183
is also remarkable for a schistose fracture parallel to the axis of the
columns. It is accompanied by a small and very unintelligible
fragment of limestone breccia, which appears here totally out of its
place, and unconnected with the surrounding rocks.
I formerly represented the difficulties which impede the ex-
amination of the Cuchullin hills. Since that period I have obtained
access to a larger portion of them, but still there is much unseen,
probably inaccessible to human footsteps. ‘That portion however
is important, and I shall here describe it, although much remains
to be done before the history of this division of Sky can he con-
sidered complete.
I remarked in the former paper that hypersthene was found
united to felspar and hornblende in the rocks which surround
Coruisk, but in the same place I also stated that a large portion of
these rocks consisted of common greenstone. I have now reason
to think this observation incorrect, and that the only greenstones
(formed of felspar and hornblende) are found in veins. The diffi-
culty of distinguishing between hornblende and hypersthene when
the parts are very minute, was another cause of error, which a
more intimate acquaintance with the place and a far more ex-
tended examination of specimens have enabled me to correct. In
thus correcting my own errors I shall also correct those of other
observers, since I may point out a well known district, Airdna-
murchan, where the same rock as that of the Cuchullin hills has
been hitherto mistaken for greenstone.
Although the hills themselves which encircle the romantic valley
and water of Coruisk are utterly inaccessible on this side, yet it is
easy every where to examine their bases, while the continuity of
the beds or sheets of rock, from the foot to the very summit of the
ridge, and its remarkable external characters, leave no doubt re-
ZA a
184 Dr. Mac Curtocn’s Supplement to the
specting the identity of their composition throughout. This is the
rock on which the elements seem to make no impression, and on
which no soil accumulates, causes which equally determine the
permanent and rugged nature of their spiry outline. I have no
hesitation in saying that the whole of the group as far as it is
visible from Coruisk, as well as the opposite side of Garsven far
on towards Loch Brittle seaward, and the smailer mountains which
separate this valley from Blaven, consist of the same rock, but to
what extent it may reach northwards cannot be determined until
the whole shall have been traversed, unless the rugged outline and
external general characters are admitted as a proof of identity of
composition. In this case the whole of the Cuchullin is a mass of
hypersthene rock, with the exception only of the veins which it
contains, which consist of basalt, compact felspar, augit rock,
syenite, felspar-porphyry, and lead-blue claystone. I have chosen
the term hypersthene rock to designate this new and important
member of the trap family, since like that of augit rock it is ex-
plicit, and introduces no confusion into the existing nomenclature.
There appear but two prevalent varieties of composition. In
the first the mixture consists of hypersthene with greenish com-
pact felspar, and in the second with crystallized white felspar
possessing generally a slight glassy lustre. This latter variety seems
to predominate, and is much more easily recognized than the for-
mer, which from its greenish hue and the minuteness and intimacy
of the admixture, is often difficult to be distinguished from com _
mon greenstone. ‘The principal variations of appearance are pro-
duced by the greater or less proportion of the hypersthene, by the
varieties of its colour, and by the unequal magnitude of the crys-
tals. While on the subject of Coruisk I ought to add, that the
sonorous rock formerly described is either a compact felspar or a
Mineralogy of Sky. 185
compound of that substance and augit in minute admixture, and
not a greenstone; a term which has been too indiscriminately
lavished on many of the obscurer members of the trap family.
The last circumstance respecting trap which requires correction
is the account of a vein passing through the marble quarry in
Strath, and supposed to terminate in a mass of syenite. I did not
in the original paper lay much stress on the conclusions which
might be drawn from it, but I can now however say that no in-
stance has occurred to me in Sky of a trap vein being cut off by
the syenite. The half opened state of the quarry at the time I saw
it, and the rubbish with which it was encumbered, misled me into
the report which I gave; a report which a moment’s view of its
present exposed state was sufficient to rectify. The trap veins (for
there are two,) enter it on one side together, appearing at first like
one; and being cut deeply through on that side of the excavation,
while they were not to be seen on the other, I readily concluded
them to be terminated. By a very singular coincidence they diverge
from each other immediately at the place of entrance, branching
away in an angle greater than a right one, and in this interval the
excavation was effected, without exposing the separated veins,
which I afterwards traced through the soil on the opposite side,
after the rubbish was in some measure removed. The remainder
of the error consisted in mistaking an irregular lump of a very
anomalous kind of sandstone which is entangled among the marble
and the trap veins now described, for the syenite which is in the
immediate vicinity similarly interfering with the limestone, and of
which, pieces detached by the workmen were lying upon this sand-
stone as if they had been recently separated from it. If care and
caution are required in examining the most simple appearances
among the regular rocks, a tenfold portion is necessary when we
186 Dr. Mac Cutiocn’s Supplement to the
are engaged in investigating the irregular ones. The whole of the
original remarks on this quarry must therefore be obliterated from
the record. .
There yet remain with respect to the trap rocks of Sky many
facts which have resulted from the later more extended examination
I bestowed on them. But as these would lead into details inconsistent
with the purposes of this paper, and as they are important rather
in a general view than as illustrating the history of that island, I
shall reserve them for some future communication.
Having thus made the additions and corrections which appeared
of most importance in the geological history of Sky, I shall proceed
to enumerate some minerals which were either entirely omitted or
but imperfectly seen.
In the small island of Oransa, and still more conspicuously in an
islet adjoining to it, there is to be found a mass of actinolite rock,
which can also be traced to the adjoining shore of Sky near to
Camiscross, It lies among the gneiss, holding an uniform and parallel
course with it, and as the beds of gneiss are here nearly vertical, it
presents the appearance of a vein, its edge alone being visible.
Nevertheless, its conformity with the gneiss, the analogy which it
bears to common hornblende-schist, and its actual gradation into
that substance, leave no doubt respecting its true character. The
edge of this bed is very irregular, as the bed itself is interrupted and
split in various places by intruding laminz of gneiss, thus contract-
ing in some places to the breadth of two or three inches, and again
enlarging to that of as many feet. It is formed of a confused crys-
tallization of actinolite of a pale green colour, the crystals being
almost always very minute, and so entangled that the fracture often
appears as much granular as it does schistose. It does not present
those varieties which occur in the well known rock of Glen Elg,
Mineralogy of Sky. 187
where the fine fibrous, granularly schistose, and distinctly crystal-
lized, occur together, nor does it, like that one, contain talc. Its
analogy to hornblende slate in a geological view is as obvious as is
the resemblance of the two minerals, and its passage into that rock
is here effected by the addition of crystals of black or greenish horn
blende, which gradually increase in number till the actinolite is
entirely excluded.
I have in another place mentioned the regular north-easterly di-
rection of the gneiss, and I think it interesting to remark that the
actinolite rock of Glen Elg corresponds with this one, as well in
direction as in quality. If a north-east* bearing be taken from it
on the map so as to intersect Glen Elg, it will be found to touch a
point near Eilan reo’ch, as near to the place of the actinolite rock
there situated as it is reasonable to expect from the nature of the
map, and I may add that the direction of the gneiss on both sides
is correspondent. There is therefore every probability of its being
a prolongation of the same bed, but to what further extent it may
be traced is beyond the bounds of this investigation to enquire.
The total distance included between the two points is about seven
miles.
In formerly enumerating the members of the zeolite family which
are to be found in Sky I mentioned laumonite on the authority of
others, although I do not know the name of the individual to whom
the discovery is attributed. Since that period I have myself found
it in the same place between Loch Eynort and Loch Brittle in
which the decomposing stilbite formerly described is to be seen.
* Allowing 24° for the variation of the needle, the bearing of this bed appears to be
north-east by east, but as the variation on this coast is not at present accurately known,
as no examination of local irregularities has been instituted, and as the maps themselves
are erroneously laid down, I have in this as in other instances held it fruitless to state
their bearings with rigid accuracy.
188 Dr. Mac CuLiocn’s Supplement to the
It is occasionally mixed with the stilbite, but is also found in very
large masses, either alone or intermixed with crystals of calcareous
spar. ‘These masses have fallen from the cliffs above, and lie de-
tached on the shore. ‘They consist principally of a confused crys-
tallization, but cavities are also found in them in which the mineral
has crystallized at liberty and in its regular form. These crystals
exceed a quarter of an inch in length, and the substance is here
invariably of a white colour. There is nothing more remarkable in
this mineral than the contrast between its present and its original
state with respect to hardness. ‘The lumps which I have described
sometimes exceed twenty pounds in weight, yet they remain entire
on the beach notwithstanding they must have fallen, together with
the other rocks which are here found, from an elevation of many
hundred feet. At the present time the slightest contact causes them
to crumble into atoms.
To the varieties of analcime which were formerly enumerated I
may add another which is also to be found at this spot. It is of a
brick-red colour, but not crystallized, and is largely mixed with the
amyegdaloidal rock that predominates at this place.
I formerly mentioned that epidote was found crystallized in cavi-
ties of the different trap rocks both in Garsven and in Glamich. In
addition to that, I may here say that fragments of the same rocks are
to be found at the foot of the former hill, in which this mineral
appears to form a constituent part of the trap, being uniformly
mixed with the other ingredients throughout the whole mass.
It has been said in some of the popular accounts of Scotland, that
agate pebbles were found near Dunvegan, but having never seen
specimens from Sky, and doubting the authority on which the report
was founded, I took no notice of this circumstance in the former
paper. I have now however found them, although in no great
Mineralogy of Sky. 189
abundance in the same place where the laumonite occurs, a part of
the coast so very rarely accessible, and under the most favourable
circumstances so hazardous to attempt, that it will not fall to the lot
of many to follow me to the same spot. ‘They are of a grey colour,
zoned in the usual manner, and sometimes contain cavities lined
with quartz crystals. Similar geodes of quartz, of considerable
size, are found in the same rocks, without the investing coat of
agate; and it is further not unusual to find crystals of stilbite, of
chabasite, and of filamentous mesotype,* sprinkled over their interior
surfaces.
Since the former account was drawn up I have also found olivin,
a mineral which, however common among trap rocks, must be rare
in the Western islands, as this is the only instance in which I have
ever observed it. A single block detached from the cliffs above, in
the place last mentioned, contains it in great abundance. It is im-
bedded in a rock the basis of which is a black indurated clay, the
same as that which here constitutes the greater part of the amyg~
daloids. It forms an equable mixture with this substance, being in
the shape of small irregular crystals, which, when after exposure to
weather the clay has decayed, appear so conspicuous, that the whole
seems a solid mass of granular olivin.
The last mineral to be added to the former list is manganese.
This is found, but in very small quantity, in an unexpected situation,
being mixed in the form of its red oxide with the white marble,
and accompanying the steatite of Strath already described. |
I shall conclude this supplement with an account of an alluvium
which I lately found in a part of the island not formerly visited,
and which is deserving of notice on account of its independent
* This mineral proves to be needlestone ; a distinction not understood when the original
paper was drawn up.
VoL. Iv. Rows
190 Dr. Mac Cutiocn’s Supplement to the
nature, and the difficulty which will be found in giving an adequate
explanation of its origin. .
It is to be observed near Kylehaken, occupying a space of about
a mile on the shore, but not exceeding a few hundred yards in
breadth, terminating in one side on the elevated ground, as it does
in the sea on the other. It seems to be the remains of a plain once
much more extensive, since its boundary towards the sea consists of
a series of straight lines, the loose materials assuming the usual angle
and exhibiting precisely the same appearances which characterize
the terraces that line the alluvial vallies through which active rivers
have cut their way. The bar of Kylehaken harbour, and the
gravelly soundings of this shore, which render it an insecure an-
chorage, equally indicate an extent once more considerable, and
confirm the supposition produced by its straight edge and the angle
of its declivity. Its surface is about 60 or 70 feet above the level
of the sea.
No rivers at present flow in the vicinity of this plain, nor is there,
from the form of the ground, any reason to suppose that they have
ever flowed so as to enable us to account for this deposit of loose
materials. The substances are nevertheless rounded, and consist of
those rocks which are seen in the neighbourhood, presenting a large
proportion of the various hard sandstones, with some occasional
pebbles of gneiss and of hornblende slate. It might perhaps be
imagined that the ordinary fragments of the mountains which back
this little plain, descending to the sea and there rolled, might have
been rejected by the tides so as to form these banks, but this sup-
position is invalidated partly by the presence of gneiss and horn-
blende slate, which do not occur among these mountains, and
partly by the altitude of the banks above the present high-water
mark. It must doubtless be granted that if at some more ancient
Mineralogy of Sky. 191
period the strait of Kylehaken was narrower than it now is, the
same tide-wave which now passes through it would cause a much
more considerable elevation of its tides. But it is already very
narrow, and no possible contraction that can be imagined would be
sufficient to produce a difference of elevation so great as would be
required for this purpose. It must be added to this difficulty that
the uniformly level surface of the plain is an insurmountable ob-
stacle to this supposition.
In defect of any other solution it can only be supposed that this
is a fragment of some ancient diluvian deposit, instances of which,
although very rare in the islands, are sufficiently abundant upon
every part of the continent of Scotland. No estimate can be formed
of its original extent, nor can any valid conjecture be offered of the
mode in which it has been so abruptly cut down. It is however
likely that although the present direction of the tides is such as not
materially to exert any action on it, that direction may have varied
in the progress of time, from alterations in the shape of the bottom
of this very narrow channel, subjected four times in every day to the
alternating action of a most rapid stream, as well as from the probable
removal of a similar alluvium from the opposite shore of the main
land. As we find analogous causes producing daily and visible
changes of the same nature in the courses of rivers, the supposition
is not incompatible with facts, since the narrowness of the Kylehaken
channel and the rapidity of its tide, give it in this respect all the
characters of an inland river as far as the contraction extends. We
may perhaps indulge our conjectures still further in supposing that
Sky was once united to the main land by means of this alluvium,
and that the gradual effect of the tides circulating through the bay
on each side had at length produced the effect in question ; an effect
not at all inadequate to its powers, and of which parallel examples
2B2
192 Dr. Mac Cuttocn’s Supplement to the Mineralogy of Sky.
occur in the lateral action of rivers on the alluvia of vallies; on the
banks of the Tay and in many others of the principal rivers of
Scotland. Greater effects have often been attributed to the corrosive
powers of the sea, and in indulging this speculation I have kept far
within the range commonly occupied by geologists. I may remark
that the narrowness of the channel, which in one part does not
exceed a quarter of a mile, and the shallowness of the soundings
compared with the depth of those which separate the other parts of
Sky from the main land, are friendly to this supposition. These
scarcely exceed ten fathoms in the middle, although there are some
deeper holes on each side ranging to thirteen, the bottom being
every where gravelly, as if, like the banks, it was the remains of
some former alluvium.
VIII. Ox the Strata in the Neighbourhood of Bristol.
By RICHARD BRIGHT, ™.p.
MEMBER OF THE GEOLOGICAL SOCIETY.
[Read 15th November, 1811. ]
With Notes extracted from the Communications of
GEORGE CUMBERLAND, Esa.
HONORARY MEMBER OF THE GEOLOGICAL SOCIETY.
AN elevated ridge of land divides the vale of Bristol fromthe
plain which is watered by the Severn. The parallel strata which
compose this ridge rise towards the north-west at an angle of about
45° emerging from beneath the horizontal beds upon which the
lower part of Bristol is built, and are afterwards broken off as they
come in succession to the surface. At the base of the western
escarpment of this ridge the lowest of the highly inclined strata abut
with their broken edges against the horizontal beds of another for-
mation, which there occupy the plain forming low hillocks almost to
the Severn. The Avon passing through a precipitous ravine cuts
all these strata almost at right angles to their planes, and exposes a
section of them ‘which may easily be observed, and has supplied me
with the principal materials for the present paper.
In the channel of the New River at Bristol a stratified red and
yellow: sandstone may be observed in strata nearly horizontal, but a
little inclined to the north-west. The thickest of these strata are
a
194 Dr. BricutT on the Strata
singularly divided into regular cubical or rhomboidal concretions,*
the planes of which cut the planes of stratification at angles of about
45°. Some parts of this rock make a fine building stone, as may be
seen in the docks, where the stonework is constructed of it. There
is a number of small cavities in the sandstone filled with crystals of
sulphate of strontian of a red or dull white colour, both colours
appearing sometimes in the same crystal.
In the low ground, on which great part of Bristol is built, hollows
occur in the surface of the sandstone, which are filled with alluvial
matter, such as clay, peat, &c. The clay is of a blue colour, and
from 10 to 20 feet thick. On digging the channel of the New
River 12 or 14 feet below the surface, a bed of peat was found more
than 2 feet thick. At the top of the peat were a number of oak
trees, tolerably sound, all lying towards the north.
On rising from the vale of the Avon to the higher part of Bristel
a siliceous iron-stone appears. Great part of Clifton is built upon
this rock, which is also found in the country south of the Avon,
forming that part of the hill above Ashton on which Sir H. Smith’s
house stands, and passing a little to the south-east of Belmont.
It is in the cavities and veins of this rock that the beautiful
quartz crystals, called Bristol stone, are found. They form 6-sided
* George Cumberland, Esq. of Bristel, has observed the same concretions, of which he
has presented to the Society a drawing. According to Mr. Cumberland the sandstone
alternates in its lower part with layers of a blue or greenish colour, and abounds with
sulphate of strontian, the masses of which contain in their cavities crystals of the same
substance of a lanceolate form and of an opake white colour. The masses are very fragile,
and fall to pieces on attempting to disengage the crystals by the hammer. Sulphate of
barytes is also found in the sandstone, but in small quantity.
+ In the alluvial matter the horns and teeth of deer, the grinders of the boar, and nuts |
have been discovered. Blue phosphate of iron has also been found imbedded in a brown
clay. The trees, according to Mr. Cumberland, had all fallen towards the south-west.
Water worn pebbles and rounded blue flints were found at the bottom of the Canal near
to the dam,
”
in the Neighbourhood of Bristol. 195
pyramids; some are of the highest lustre and transparency, others
variously coloured by iron ore, or containing acicular crystals of that
substance, or of manganese ; some are said to be pierced with needles
of sulphate of strontian.
Behind Brandon Hill there are beds of sand highly impregnated
with iron, and containing impressions both of shells and vegetables.*
In the descent on the south of Brandon Hill some singular masses
of breccia project from the ground, containing rich iron ore, and
assuming nearly a cubical form. The siliceous iron-stone of Brandon
Hill has been found to make the best grinding stone for enamel
colours. Below the siliceous iron-stone, upon the banks of the river
near the Hot-well House, three small beds of coal make their ap-
pearance. These have been worked close to the river on its southern
bank: and on the northern at the distance of two miles, near the
Fort, a trial for coal was made some years since, but the seams found
were not worth working.
Upon the banks of the Avon, immediately below the coal, there
is found an extensive series of beds consisting principally of limestone,
which form that high ridge of land which has been already noticed.
This ridge passes on the north to Almonsbury and Alveston, and
on the south to Clevedon, where the coal field of Nailsea begins.
These beds upon the banks of the Avon are remarkably regular in
their stratification, being all nearly parallel to one another and
dipping to the north-west at an angle of about 45°. They are better
observed on the northern than on the opposite bank, being on the
former very much exposed by the operations of the quarrier.
Upon the top of this ridge and upon the fractured edges of the
limestone strata, behind Clifton, there has been a partial deposition
* Mr. Cumberland mentions the anomia producta as found in the sandstone which lies
above the limestone.
fe
aA
196 Dr.. BRIGHT on tie Strata
of stratified yellow sandstone, forming what has been called an up-
filling. In the fissures of this rock crystals of carbonate of lime are
found, and crystals of sulphate of strontian, which often assume a
radiated form. This sandstone, having sometimes the appearance of
a breccia extends to Redland. It is probably spread over the surface
of the siliceous iron-stone already described; and in such a position
it seems to have been found on Kingsdown in digging the vaults of
Portland Chapel. The sandstone was there less firmly agglutinated,
and the sulphate of strontian occurred about 4 feet below the surface
in large irregular balls weighing many pounds.* At Redland this
sandstone and the strata upon which it rests are rather abruptly ter-
minated, being covered by a limestone stratified horizontally in thin
Jayers, containing ammonites, gryphites, and anomiz in abundance,
and agreeing in all its characters with the well known limestone
called /yas. The lyas extends to Cotham, where some of the strata
are remarkable for taking a beautiful polish, being known at Bristol
by the name of the Cotham stone. This lyas burns to a brown
lime which sets hard under water.
But to return to the limestone. I do not intend to describe in
detail all the beds of it; but the following are what I thought best
deserving of notice, from their commencement immediately below
the coal down to the lowest in the series. The first part of the
series is best observed on the northern bank of the river.
* A beautifully crystallized specimen from these excavations was presented to the
Society by Mr. Cumberland, It was found together with many other masses of the same
substance imbedded in yellow marl. On digging the excavation for some houses at Clifton,
according to Mr. Cumberland, the following minerals were found, but it is not known in
what bed the vein occurred to which they belonged. Crystals of galena with foliated
sulphate of strontian upon a matrix of sulphate of barytes. Quartz crystals enveloping
needles of sulphate of strontian. These excavations are now closed, and the ground being
built upon the minerals can no longer be procured.
in the Neighbourhood of Bristol.
1. A mass of limestone composed almost entirely of organic
remains, and containing much iron, with madrepores between
197
ORE del si year HR ARR E oUTRRG meey Aveo) SO feet
2. Ten thin beds of blue and close-grained limestone, with
clay between them, in which madrepores are imbedded . .
3. Limestone composed entirely of particles bearing marks
8
RB AMIODY fog the o's ofa Pio a ghe rts Wes mero e 18
4, A very thin stratum of red clay, covering
5. *A layer of coaly matter, one inch thick.
* The following more detailed section of the beds lying above the coal marked No. 5, iz
the text, has been communicated to the Society by G. Cumberland, Esq.
1,—Sparry limestone, the edges of which being tinged with iron resemble Ft. In.
Aaa ith sar ietsens Saat ste stevernieferals cre eteye feet
2—Red, blue and white!schistose clay vv. dices eS eenaseccecaevce® ee
3.—A stratum very full of fissures, the laminz composed of quartzose sand
united by! arquarteose COMOME ta0, wd fpcirferere evepeie wie we
4,—A stratum of what is called ‘Dun marle,” containing very angular frag-
ments of limestone and ironstone: the marl is red, blue and white, and
is speckled with ferruginous sand and pieces of schistose clay .,......
5.—A very hard mixture of ironstone and quartzose sand with portions of an
oolitic texture....... See es VE. SEE Oo TO eco pete Fe cit Seas
6.—A_ ruddy and arenaceous limestone, ochreous, passing into ironstone of a
fine grain, .. veh» awhkt vel bors fa wiladts sed cprepiciinte Aah) owed fap. ste te
7.—A stratum of ironstone 1 inch thick; then a very hard and fine grained
arenaceous stratum .,..,.,.. Bisip olitle » leccwo}ee farsi oe hovers seereens
8.—A fine grained arenaceous stratum...... pid creteiniee tain SAIC Gr Oe en
9.—A stratum containing fragments of shells.......... pee iate are) eee areolar oe
10.—A stratum containing fragments of shells and corals, in part argillaceous,
and having the oolitic texture ; of a brown colour...........+++ pistes
11.—Three inches of ochreous clay with blue schistcse clay, with oblong geodes
OF Ted Wewrore Very COMpPACe AMG HATE cos pos fos ccc s oes esis se 56
12.—Limestone having throughout the oolitic texture..........++2--+00- eee
13.—Schistose clay or stone with nodules of coral .........06...+-.. alates ar
14.—Very arenaceous limestone with oolitic texture.......... es eeee cevsese
15.—Schistose wet clay coloured by iron with nodules ...... aS hacia het ea .
16.—Limestone, somewhat oolitic, tinged with iron, containing broken shells. .
VOL. IV. Zc
10
26
9
12
ae
198 Dr. Bricut on the Strata
6. Blue clay divided by bands of yellow clay . . feet 12
7. Limestone resembling No. 3, this occurs at the distance
of about 100 yards west of the Well house.
8. Limestone that is quarried as being fit for burning,
forming magnificent cliffs about ; mile beyond the Hot-well
house.
Ft. In,
17.—Dove-coloured, oolitic limestone with broken shells. The strata cracked. 8 3
18.—Grey compact limestone, irregularly Oolitic 2... 1... 6. cece eee ee ee ees 6
19.—A stratum somewhat arenaceous, tinged with iron ............-4- i oh. 9 aS
20.—A schistose limestone ....... Sir eho orca cc clean Bods 6 ab aig cid ry 1
21.—Two layers of soft limestone tinged with iron, separated by a layer of schis-
tose clay 2 inches thick ...... SOC Esty orcatyes “pane, Sher gia oAN wateres Be
22.—Dark and fine grained limestone, divided in part by loose schistose clay .. 2
23.—Seven thin layers of schistose limes tone, separated by loose friable schistose
clay with nodules, the whole containing many shells of the winged
anomie and the anomia producta, with coralloids ....... DRE 3
24.—Light coloured and fine grained limestone without animal remains, in
LEXtUTE TESEMDMME ING. 22 heats sme. cme ae tts HA IAL AU pera
25.—Limestone with small broken encrinites ......... RIGS ys PED wats 2
26.—Dark oolitic limestone with broken shells ....... Ba LE a NISRA Ne he
27.—Limestone with broken shells throughout ............ UBIO, HR ETS, ie 1
28.—Schistose clay..... qatereteretetetetet ot el ehntotstetelatetetetere re ‘aletete” te PUL Raat ots 3
29.—Fine siliceous rock without shells...........0....4. PGP ARE AVR LMS eh wh 6
£0.—Rock with oolitic structure partially coloured by blue clay ............ ou 5
31.—A reddish limestone with small arms of the encrinite, their cavities filled
with ochreous matter 2.2%"... s. sens et usitcss JURY RUG IAI. 6
82.—Coal about 2 inches thick, resting upon ironstone and red schistose clay,
three, or four inches thie kar,» ogy « «calc idiays Biehl hak axle ieee ae 6
Of these strata only two will burn into good lime, the rest being too arenaceous for the
purpose. ‘The organic structure observed in No. 3, of Mr. Bright’s section is the oolitic
texture noticed by Mr. Cumberland. Mr. Cumberland observes that although this texture
is still visible in the arenaceous rocks of a mixed nature, it disappears in those which are
purely siliceous. He also mentions that an oolitic limestone may be observed lower in the
series of the east side of the combe that separates the pure limestone from the black rock
or swine-stone. ‘The fossils of the black rock are the winged ayomia, and rarely the
anomia producta, the palates of fishes, the claws of crustacee, corallines of various kinds,
the mycétite of Woodward, the medusa encrinite, and millions of the stalks of encrinites,
in the Neighbourhood of Bristol.
9, Limestone in thin strata, impregnated with ochre so as
to be unfit for burning.
10. Ferruginous marl, containing a great many madrepores
and shells quite detached from the rock.
11. The first quarry of limestone.
12. The second quarry of limestone. In the limestone of
these two quarries the strata although separated by no inter-
vening substance are very perceptible, preserving an uniform
direction.
13. Several thin beds of limestone which are not worked.
14, At the distance of three or four hundred yards from
No. 12, the assemblage of strata begins, which forms what is
called the Black rock, so called from the dark colour of the
stone. A third quarry is worked here. This rock is
less tinged with ochreous infiltrations than the rest usually
are: it contains a great many shells and entrochi, and in its
cavities are found dog’s-tooth spar, cubes of purple fluor,
acicular crystals of sulphate of strontian, and of oxide of iron.
Similar cavities occur in the rock of the preceding quarry.
15. Many thin beds of limestone divided by clay, some
being very full of shells and entrochi, and others having
scarcely any traces of organic matter. Some of these strata
from the number of shells they contain may be recognised
again on the rising ground at the foot of Leigh Down near
the village of Leigh, on the southern side of the Avon.
199
*
both round and oval. There has likewise been found in it a complete specimen of the
head of an encrinus, and other heads of the encrinus have been observed imbedded in the
limestone, and but little distorted. They were first noticed by Mr. Miller surrounding
calcareous concretions in the black rock, which are penetrated with petroleum.
Petroleum sometimes exudes from the rock in small quantity ; it is very hot to the taste,
and is used by the masons for an external application, assisted by friction, to remove rheu~
oo
matic pains. The black rock is quarried for paving stones.
Cra
200 Dr. BricuT on the Strata
16. A thin bed of limestone breccia containing rounded
pebbles, and organized substances resembling the palates of
fish. This bed has not been traced on the southern bank.
17. Limestone highly crystallized, containing much iron,
and composed in a great measure of organic matter. It is
seen very distinctly on the northern bank of the river crop-
ping out amongst the wood, and resembling a wall about
8 feet high.
The limestone of St. Vincent’s rocks when calcined yields a very
pure lime: large quantities of it are exported for the use of the
sugar works in the West Indies, in an unslaked state and packed in
tight casks, and it is used extensively for building. All the roads
in the neighbourhood of Bristol are repaired with the limestone, as
are those in the neighbourhood of Gloucester, whither it is conveyed
by means of the Severn.
Calamine is the most important mineral in point of frequency and
value that the limestone yields, It is found in veins of calcareous
spar crossing the limestone, accompanied by heavy spar and fre-
quently by galena. The calamine is either amorphous or assumes
the form of calcareous crystals which have been encased by it and
since removed. The calcareous crystals in these veins have generally
the dog’s-tooth form ; the heavy spar is not crystallized, but appears
fibrous or composed of thin lamine lying above one another. The
galena sometimes presents very regular cubes, the angles of which
are generally truncated. The calamine has hitherto been worked in
a very imperfect manner: the vein is broken into, when it meets
the surface; a rough windlass is placed over the hole, and a
bucket is attached to a few fathoms of rope; two or three men
work at the vein as long as the ore is found in abundance, or until
the water impedes their progress. The mine is then deserted, but
Se
in the Neighbourhood of Bristol, 201
the heaps of rubbish at the mouth of the pit are often so rich in ore
that considerable sums are paid for the privilege of washing them.
Manganese is also found in this district: it has not however been
worked to any extent. The principal pit from which it is taken is
in the parish of Ashton on the slope of the hill overlooking the
valley to the west of the church. It is found in an iron-stone vein
crossing the limestone. What little is found is used at the glass-
houses and potteries of Bristol, and at the bleach yards in the neigh-
bourhood.
To the limestone succeed other beds, in which a red siliceous
sand is the prevailing ingredient. They lie in very regular strata
from a foot to two inches thick, and parallel to those of the lime-
stone. ‘They are best observed on the southern bank of the river
along the towing path for the distance of about half a mile from
where the limestone terminates. These beds extend on the south
of the Avon to Leigh, Failand and Charlton, and on the north they
pass near to Sneed park towards Westbury. Some of the beds of
this formation near to Abbots Leigh make a fine stone for building.
Among the uppermost of these beds are several composed of sand-
stone, the fissures of which are coated by calc-sinter, then a thin
stratum of sandstone with evident marks of vegetable remains ; below
which is a red slaty sandstone very micaceous, and then a bed of
siliceous puddingstone about 12 feet thick containing in some parts
a number of white quartz pebbles.
About the middle’ of this series of sandstones there is found a
singular stratum about 3 feet thick, composed of irregular balls of
limestone packed closely together, the intervals being filled with fine
sand. Below this the red slaty micaceous sandstone is repeated and
at length disappears, being the last of the highly inclined strata that
can be distinguished.
-
202 Dr. BrtcuT on the Strata
The last of these highly inclined strata at the base of their western
escarpment are generally covered by beds of a very different character,
which lie in horizontal layers upon the broken basset edges of the
lowest beds of sandstone. This arrangement of the two formations
may be observed to the south of the Avon on the towing-path just
where the beds of sandstone terminate, and to the north of the river
near to Sneed Park; at these places the sandstone is covered by
horizontal beds of that kind of breccia which I shall presently de-
scribe. These horizontal beds form a series of low hillocks extend-
ing from where the sandstone terminates to within two miles of the
Severn. ‘They are best observed on the southern bank of the Avon,
at Hung-road near to Crokerne Pill, where their section is exposed
at low tide in a perpendicular cliff nearly 60 feet high. The beds
consist of a red loamy earth and of breccia arranged in the following
order.
Breccia. |ao...aoshupela) saetelb malin udeeeers
Red loamy earth, about . . . 30
Breccia extending to the base of the cliff, and quite below
low water mark.
The upper and lower beds of breccia present nearly the same
characters. They both consist of calcareous and siliceous fragments
cemented together by a calcareous hase, having cavities in it, which
are filled with calcareous and siliceous crystals, and sometimes with
sulphate of strontian. ‘The calcareous crystals have either the form
of the primitive rhomb, or of the dog’s-tooth spar, and are sometimes
covered over with an incrustation of smaller crystal’ of carbonate of
lime. The quartz is crystallized in six-sided pyramids. Besides the
sulphate of strontian which is found crystallized in the cavities in
small quantity, it occurs in large masses either imbedded in the
breccia, or lying between the two beds of it. It occurs in blocks of
s
—E———— OEE —
in the Neighbourhood of Bristol. 203
many cwts, in the fields between Ham Green and Leigh, and I am
inclined to believe that these are derived from the red loam which
lies between the two beds, for I found a mass of it in a ditch lately
dug on the slope of the hill below the basset of the upper breccia ;
but the circumstances were not altogether decisive. The sulphate
of strontian from this place is seldom found well crystallized, the best
of the crystals that I have met with being tables not exceeding 7th
of an inch in length. The entire masses are generally snow white,
having the appearance of a coarse grained loaf-sugar, but sometimes
they acquire a reddish hue from a small quantity of ochre.
Small veins of galena are found in the breccia. The breccia is
found near to Abbot’s Leigh, from whence it extends in a position
almost horizontal to Crokerne; and it probably occupies the whole
space included by a line drawn from Leigh through Failand, Charlton,
Portbury and Portishead, and thence returning again through Crokerne
to Leigh. On the opposite side of the river it forms the stratum
beneath Shirhampton, and runs up the valley below King’s Weston
hill, extending to the east as far as Sneed Park. In some parts it is
found at so high an elevation as to lead to a belief that there may
be more than two beds of the breccia: in whatever situation how-
ever it is met with its general characters are the same.
The red loamy earth at Hung-road is traversed by veins of fibrous
carbonate of lime, which are about an inch thick, and contains hollow
calcareous nodules which are often lined on their inner surfaces with
beautiful calcareous and siliceous crystals. The quartz varies but
little in form 3 it is almost always in very short six-sided prisms
terminated by two six-sided pyramids. It sometimes contains acicular
crystals of iron ore: is generally transparent and colourless, but
sometimes assumes an amethystine tint. ‘The calcareous crystals vary
very much in form, sometimes exhibiting that of the primitive
‘ °
i
904 Dr. BricuT on the Strata
rhomb, sometimes that of the dog’s-tooth, and sometimes very com~
plicated figures with numerous truncations. The whole cavity of
the nodule is generally lined with small crystals, which are highly
phosphorescent when thrown on an iron plate heated almost to
redness.
On cutting through the loam there is generally found a bed of
ochreous iron-stone about 14 foot thick. It is not known to what
distance this bed of loam extends. The nodules have as yet been
found chiefly in Hung-road wood, and some varying a little in ap-
pearance are seen on the opposite side of the river.
To the west of Crokerne Pill you find only a low alluvial plain,
scarcely raised above high-water mark, and this continues on both
sides of the Avon until it falls into the Severn.
With regard to the springs in the district 1 have been describing,
it may be observed that those in the limestone are low and situated
in the ravines, breaking out in many cases between high and low
water mark. The hot spring at the Wells rises in the limestone 26
feet below high. water mark, and 10 feet above low water, and no
water is found at Clifton until the wells are sunk nearly to that
depth. When you come to the sand-ridge upon which Leigh is
situated, the springs are always found to rise in a high level, and
they afford a good supply of water. In the horizontal strata to the
west of Leigh very good water is obtained by sinking to the second
or thick bed of breccia, or at the utmost by sinking a few feet into
the stratum. There is a little spring in Hung-road wood which
though perfectly clear has the property of covering every thing over
which it flows with a brown calcareous crust. The quantity of
water is small, and in summer the stream is frequently dried up.
As to the nature of the soil, the valley of Bristol and Ashton is as
verdant an extent of pasture land as any in the kingdom. Its rich
Dr, BricuT on the Strata in the Neighbourhood of Bristol. 205
green colour is contrasted with the dark foliage of the elm, which is
the prevailing tree of the county, very few oaks of considerable size
being now found.
The limestone district has as yet produced little but heath and
fern, the rock in general approaching too near the surface to be
favourable to vegetation. Much of it however has been lately en-
closed on the southern side of the river, and a part of that is of good
‘promise. Within the limits of the sandstone and of the breccia there
is very fertile grazing land.
Note on Magnesian Breccia.
By HENRY WARBURTON, Ese.
VICE PRESIDENT OF THE GEOLOGICAL SOCIETY.
[Read 2ist June, 1816. |
THE great stratum of magnesian limestone which passes from
Sunderland in the north of England through the centre of the
midland counties, suddenly terminates, as is well known, in the
vicinity of Nottingham; and I am not aware of its reappearance
in the south of England having been noticed except perhaps on the
north-eastern border of the Ashby de la Zouch coal-field, where it is
said to occur in great insulated masses.
The geological relations of this rock to other strata appear to have
been well ascertained in the northern and midland counties, where
it is described as forming horizontal beds, and as lying under and |
parallel to the red marl, or occasionally as alternating with it. It has
been ascertained by numerous sinkings in the same counties that the
VoL. tv. ) 2D
206 Mr. WARBURTON on Magnesian Breccia.
magnesian limestone lies over the coal measures ; it is doubtful how-
ever whether the ccal measures are conformable with the strata of
the magnesian limestone; and it is not improbable that they lie
under it, having the edges of their tilted and broken sills abutting
against the lower surface of the superincumbent rock.
The red marl is so widely distributed in that part of England
which lies between Lancashire and the southern coast of Devonshire,
and is so frequently found in that district in the same geological
position which it occupies in the northern and midland counties in
alliance with the magnesian limestone (lying for instance in horizontal
strata upon the inclined coal measures, and bounding them at their
basset) that it might be expected in some part of its course to dis-
cover traces of the magnesian rock. Accordingly I shall mention
some instances of the occurrence of a magnesian limestone in the
district above referred to, where it either alternates with red marl, or
may be considered as connected with it.
In the course of a valuable paper on the Rocks in the vicinity of
Bristol, which was long ago presented to this Society, the author,
Mr. Bright, has given an account of the strata of red marl which lie
along the banks of the Avon. The red marl is there found either
lying upon the coal measures, or filling up the vallies that are occa-
sioned by the breaking off of the inclined strata of limestone, where
instead of the series of inclined strata that should rise from beneath
the limestone, horizontal strata of red marl are found resting upon
the broken edges of the limestone or of the first of the rocks beneath
it. It is in the red marl last described, as it occurs near Hung-road
on the Avon, that Mr. Bright discovered a limestone breccia, of
which there are two beds alternating with red marl.
Having examined this breccia on the spot, after having consulted
Mr. Bright’s paper, and having seen some breccias from the Mendip
Mr. WARBURTON on Magnesian Breccia. 207
Hills of which I knew the nature, and which very much resembled
those from the banks of the Avon, I had no difficulty in ascertaining
that the cement of the latter was composed of magnesian limestone ;
of which indeed the characters are so strongly marked as to be
evident on mere inspection. ‘This breccia consisted of rolled frag-
ments of milk white quartz, and of angular fragments of limestone
and sandstone such as are found in the neighbouring inclined strata
cemented together by yellow magnesian carbonate of lime; the
cement being in great excess. I must refer to Mr. Bright’s paper
(which I understand will soon be published) for the further descrip-
tion of this rock.
Shortly before seeing the rocks of Hung-road, I had been with the
late Smithson Tennant, Esq. to examine the magnesian breccia which
he had observed on the Mendip Hills near to the celebrated cliffs of
Cheddar. The southern declivity of that limestone chain is there
deeply furrowed by wide and extensive combs, in which immense
blocks of the breccia many yards in diameter are found lying upon
the surface of the limestone. The strata of limestone dip to the
south under an alluvial valley, by which they are separated from a
low chain of red marl that is found at the distance of about half a
mile to the south.
The breccia of the Mendip Hills very much resembles the breccia
from the Avon, consisting of fragments of limestone, magnesian lime-
stone, and sandstone cemented together by a yellow magnesian car-
bonate of lime; but I never discovered in it any of the quartz pebbles
which are imbedded in the breccia from the Avon.
Until I had seen the breccia at Hung-road I was unable to account
for the presence of these immense insulated blocks upon the sides of
the Mendip ; but I have since ventured to conjecture that they once
formed a subordinate bed in the strata of red marl which are found
2d2
208 Mr. WARBURTON on Magnesian Breccia.
on the other side of the alluvial valley of the river Axe, and which
perhaps were originally continuous across the valley and rested
mediately or immediately upon the limestone ; but which have since
been removed by denudating causes, the hardest and most durable
part of their mass, the magnesian limestone, being left behind.
I have heard of the following additional cases in which a mag-
nesian breccia is found in connection with red marl. Dr. Wollaston
in the first instance and afterwards Mr. Greenough informed me
that a similar rock was found near to Cowbridge in South Wales, a
specimen of which was presented by the latter to the Society. Mr.
Aikin also has noticed a breccia of the same description at Caerdeston
and Loton in Shropshire.
In thus comparing the magnesian breccia of Bristol with the yel-
low limestone of the northern and midland counties, I have assumed
that the red marl which lies above the coal measures is of the same
order with that which lies at the bases of those escarpments, where
strata of mountain limestone are broken off; and where instead of
the lower beds rising from beneath the limestone we find horizontal
strata of red marl filling the plains. I am not prepared to establish
this by any positive proof; such evidence as the geology of the plain
of Carlisle would afford is already in the hands of Mr. Buckland ;*
the appearances that are to be sought after for determining this
question, and which perhaps may be observed in the neighbourhood
of Bristol, are the following: no disposition of the strata is more
common in the country between Bristol and the Mendip than that
described in Mr. Bright’s paper; where a ridge of mountain lime-
stone separates two plains from one another, each containing hori-
zontal beds of red sandstone or marl, the one lying above the lime-
* See his paper, page 105 of the present volume.
vam
Mr. WARBURTON on Magnesian Breccia. 209
stone with the intermedium (perhaps) of the coal measures, the
other abutting against the broken edges of the strata of limestone at
the base of its escarpment. Perhaps there may be found some valley
of denudation connecting together the two plains, which being itself
filled with red marl of the same description, there may be an unin-
terrupted bed of marl through the valley from one plain to the other.
The determining of this question would be of some importance
as a matter of speculation, and of some practical consequence to the
coal viewer. ‘Those who consider the red marl as one of a complete
series of beds succeeding one another in a uniform order, will in
every case expect to find the coal measures on sinking through the
red marl. If on the contrary we suppose denudatory or other dis-
turbing causes to have been in action previously to the deposition of
the red marl, we might expect to find the red marl immediately in-
cumbent upon any rock from the coal measures to the granite inclu-
sive, just as the alluvial beds in which the bones of elephants are
found in consequence of previous denudation are discovered resting
either upon the blue clay of London, upon the Oxford oolite, or
any other bed: and on this view of the subject the red marl will
no more be an indication of coal than of any other member of the
Jower strata,
IX. On the Maguesian Limestone and Red Marl or Sandstone
of the neighbourhood of Bristol.
By W. H. Gitsy, M.D.
[Read November 15th, 1816. ]
Tue present communication originates from my having dis-
covered in this neighbourhood the magnesian limestone which
exists so extensively in the North of England; and as its position
with regard to the other formations is remarkably distinct, we have
here at least an opportunity of ascertaining its true geological rank,
concerning which much uncertainty has prevailed in other quarters.
In the description which I have given in the Philosophical
Magazine of the geology of this neighbourhood, it will be seen
that we have here two grand divisions of rocks, one occurring al-
ways in inclined, and another in horizontal strata. The lowest
formation of the first class is the first floetz or old red sandstone,
exceedingly well characterized. It is only in certain tracks that
this rock constitutes hilly ground so as to be visible to the eye:
but the first floetz or mountain limestone which rests upon it, has
a very extensive range, describing in its course an irregular ellipsis,
the direction of which it will here be unnecessary to repeat. I may
however remark that analogous to what has been observed with
regard to the ellipsis of mountain limestone in South Wales, the
dip of its strata varies remarkably in different parts of its course.
At the north the strata dip south, and at the south, north. On the
Dr. GILBy on the Magnesian Limestone, '&c. 211
east they have a western dip, and on the west an eastern one. In this
way the strata tend every where towards a common centre. In
the hollow of the basin so formed is deposited a very extensive
coal formation, for the particulars of which I refer to the above
description. It is sufficient to say that the coal beds and coal mea-
sures are always inclined, and when contiguous to the mountain
limestone they always dip conformably with it.
It is upon the tops or edges of the inclined strata of these forma-
tions that we find the strata of the second division, that is, the hori-
zontal rocks, superimposed in an unconformable position. ‘These
horizontal rocks are the same with those occupying so large a por-
tion of the south and south-west of England. The lowest of them
are the beds of the red ground, as this formation has been absurdly
denominated, consisting of a coarse limestone conglomerate, above
which lies a calcareous sandstone, red and white in different places,
and then a deposit of red clay, containing gypsum and sulphate of
strontian. Above this red ground formation occurs the well known
lyas limestone, then the oolites or Bath stones, and lastly the chalk.
The basis of the red ground conglomerate I have generally found
to be a common limestone; but being lately at a village on the
Bristol Channel called Portishead, I was surprized to find the basis
of the conglomerate of a yellow colour, and resembling in appear-
ance some varieties of the Yorkshire magnesian limestone. Upon
analysis I found that it did contain a considerable quantity of car-
bonate of magnesia, the proportion of which varies in specimens
taken from different strata. In some strata the basis is so much mixed
with sand as to give more than 20 per cent. of insoluble matter,
consequently the quantity of carbonate of magnesia is much di-
minished. The fragmented portions are generally limestone or
red sandstone, but we find some strata destitute of sand and frag-
212 Dr. GiiBy on the Magnesian Limestone, Se.
ments, forming in fact a hard compact magnesian limestone. This
variety will give 36 or 38 per cent. of carbonate of magnesia. All
- the varieties are of a yellow colour, and like the magnesian lime-
stone of the north, it often exhibits black spots throughout its
substance, and it frequently contains impressions of shells.
The analysis of the compact variety, conducted in the usual
way, gave me of
Carbonate of lime - 3° .°"53.5
Carbonate of magnesia . 37.5
Oxydor iron or. hers 8
Insoluble matter . . . 7.
Licey Se, Sr Ee, 0? eee eee
100.0
Now with regard to its geological relations, it in no respect
differs from the limestone conglomerate which I have mentioned
as the lowest bed of the red ground formation. I have traced it
in a continued line by the sea side from Portishead to Clevedon,
and it every where contains the same fragments and every where
lies horizontally and unconformably upon the inclined strata (which
are there the old red sandstone,) in the same way that the usual
red grained conglomerate does. It is therefore plainly to be con-
sidered as the lowest stratum of the red ground formation, and
consequently succeeds immediately to the coal deposit.
It seems to me that the magnesian limestone of the north of
England may be referred to the same formation. In Thomson’s
Annals there is lately a short notice of a paper read before the
Geological Society by Mr. Winch, upon the magnesian lime-
stone in the north of England, in which it is stated that the Tees
of the neighbourhood of Bristol. 913
flows over bedsof white and red calcareous sandstone contain-
ing gypsum, which rests upon magnesian limestone. Now this
gypseous calcareous sandstone may be said to characterize the red
ground, therefore the magnesian limestone in that district may be
safely referred to that formation, and consequently may be regarded
as the rock next in succession to the Durham coal deposit. This
indeed might be collected from the imperfect sketch Dr. Thomson
has given us of its occurrence in that quarter. In a late number of
the Philosophical Magazine, it is said that the coal formation of
Whitehaven is covered at St. Bees Head by bituminous clay, over
this is a limestone containing magnesia and iron, and above this is
a red sandstone, connected with which is clay, marl, and gypsum.
This it will be perceived is almost an exact account of the succession
of the red ground strata in this quarter. In Derbyshire we are
informed that the magnesian limestone lies in an unconformable
and horizontal position over the inclined strata, after the manner
of its occurrence in this quarter, it therefore plainly belongs to the
same formation, the red ground.
It may seem at first very remarkable that the basis of the lime-
stone conglomerate should be in one place merely a common lime-
stone, and that in another spot, not far distant, it should contain a
considerable proportion of magnesia. ‘To those however who have
seen how widely the same rock formation, nay even the same
stratum, will vary in its colour, hardness, and general structure in
different parts of its course, this will cease to be a matter of wonder.
In attempting to explain these singularities, it seems to me that we
must resort to one of two suppositions: we must either conceive
that the fluid menstruum during the deposition of any particular
and extensive formation, must have contained in different places
different chemical ingredients ; or we must conclude that the altera-
VOL. Iv. 2E ,
214 Dr. Giusy on the Magnesian Limestone, &c.
tion in structure in an individual formation, has not so much been
derived from the addition or substraction of certain chemical in-
eredients as from the proportion in which these ingredients have .
crystallized. According to the latter view, during the consolidation
of any particular formation, the constituent particles, although few
in number, may in different parts of the crystallizing mass have been
attracted together in new proportions, so as to give rise to those
variations in colour and structure which we so frequently witness.
The originality of this theory of crystallization belongs to Professor
Jameson, and it seems to me very happily to explain many anoma-
lous appearances of disorder and brecciated structure, which have
caused great embarrassment to geologists. In some cases however
this theory cannot be applied with any degree of probability. Where
we see a particular assemblage of strata, as the limestone conglome-
rate, manifestly of the same formation, exhibiting in several parts of
its extent changes of composition altogether depending upon a dif-
ference in its chemical constitution, it is impossible to explain such
an occurrence but by supposing that the fluid menstruum must have
contained in different places different chemical ingredients. Every
geologist will figure to himself illustrations of the want of uniformity
in the same rock formation. I may mention however two other
striking facts of this nature. The red clay of the red ground is met
with in almost every part of England, and almost every where does
it contain or is connected with gypsum ; but besides gypsum, in this
neighbourhood only, it abounds with sulphate of strontian in the
form of veins and even large beds, From Mr. Webster’s account
of the strata above the chalk in the Isle of Wight, it seems quite
manifest that what he calls the first fresh water formation was
formed at the same period with the marl and gypsum of the Paris
of the neighbourhood of Bristol. 215
basin, containing the bones oP Birds and fish, but an important differ-
ence is that the English strata are destitute of gypsum.
We sometimes meet with magnesian limestone subordinate to
the first flactz or mountain limestone. Sometime ago I discovered
a very beautiful sparry dolomite lying in conformable strata upon
the mountain limestone near Ross in Herefordshire. ‘This variety
contains 44 per cent. of carbonate of magnesia. A small ridge
of rock, about four miles north-west of Bristol, upon which Lord
de Clifford’s house is built, is entirely composed of a magnesian
limestone abounding in shells, entrochi, and madrepores ; and in an
adjoining hill which overlooks Blais Castle it occurs, as far as I can
understand, interstratified with the mountain limestone.
A specimen of this variety I find to be composed of
Carbonate of lime . . . . 58
Carbonate of magnesia . . 38
Oxyd of arom 5750" SHY Bit P15i
Silica and bituminous matter 1.5
Rage. bide terror ince we att bee
100.0
e
I may remark that this magnesian limestone varies remarkably in
specimens taken even from contiguous situations, both in colour and
other external characters. It is therefore probable that these varieties
would afford slight differences in their chemical ingredients.
I am entirely indebted to Mr. Bright, of Ham Green, for being
able to give the last mentioned locality of this rock; for upon in-
forming him of my present pursuit, he desired me to examine the
ridge to which I have just alluded, as he conceived it to be com-
posed of a magnesian limestone.
222
X. On the Strata at Whorlbury Camp, in Somersetshire.
By GEORGE CUMBERLAND, Esq.
HONORARY MEMBER OF THE GEOLOGICAL SOCIETY.
[Read 3d November, 1815. ]
W HoRLBURY CAMP is a considerable Roman station situated
just above Weston-super-Mare on a high and well defended pro-
montory that projects into the Severn sea. At the foot of the
promontory, and at its northern extremity, is a small island, con-
nected to the main land by a bank of rocks, and always accessible
at low water. The island contains about three acres of green sward,
the remainder of the surface consisting of limestone rocks, which
are deeply excavated. It serves during the sprat season as a place
of resort for fishermen, who have extended their sprat-bangs from
the island to the main land.
A narrow horse road forms the descent from the downs in the
island to the level of the sea, and it is just where the road begins to
quit the sward on the left hand side opposite the sea, that a narrow
stratum of soft red sandstone appears. ‘This sandstone is of the
consistence of schist at its surface, and has its lamine divided by a
hardened ochreous marl. Its whole thickness is about 6 feet, and it
dips at an angle of about 47°.
Mr. CUMBERLAND on the Strata at Whorlbury Camp. 217
In the marly part of this stratum a fossil is found resembling a
cane or jointed bamboo. It is rarely obtained more than five inches
long, generally curved, but sometimes straight, and of all degrees of
thickness from a quarter of an inch to five inches, These fossils lie
in great disorder, and are apt to separate at their joints on extracting
them from their matrix ; and many appear to have had their joints
separated as they lay in the sandstone, the ends of the joints being
covered with a thin coat of quartz. Many of these fossils have
their hollows between the joints filled with hard sandstone, but the
greater part have their centres quite filled with the hardest white
quartz; and where there are cavities, which rarely happens, they
are sometimes found to contain crystals of calcareous spar.
When I first discovered these fossils, ten years ago, I found them
upon the beach just under the sandstone rock, and took them for
corallines; but having since found them abundantly in situ, and
examined a number of them more minutely than before, I am in-
duced to regard them as juncous bodies. I know not at least how
to class them as corals, since they have not the smallest trace of any
passage from one joint to another. Should they be ranked however
among the coralline bodies, they must be allowed to be of a very
singular nature.
Below the beds containing these fossils a grey limestone is found,
in which no traces of marine bodies appear.* On the top of this
limestone is a thin bed of very yellow marl, and then a thin bed of
purple and blue marly earth. Then appears the red sandstone con-
taining the cane fossils, six feet thick. Above it is another bed of
* Upon the summit of the hill at Uphill (which forms the point of the bay of Weston
opposite to Whorlbury) the canes are found in a coarse grey limestone, and may be
observed on the same spot in the stones of a ruined mill accompanied by small shells of
the winged anomia.
218 Mr. CuMBERLAND on the Strata at Whorlbury Camp.
Cd
blue and purple marl about three feet thick, and above that a con-
siderable bed of limestone of g reddish grain, over which is found a
bed of compact red limestone, without fossils. Above this is a vast
mass of coarse limestone without fossils, and beyond it many con-
siderable strata of grey limestone, succeeded by others that are thin
and exhibit on their surfaces, when exposed to the action of the sea,
some traces of the fossil I have been describing.
Just above the ends of the strata that contain the cane fossil,
which at the distance of a few feet would have cropped out on the
sward of the downs, there is found a mass of a partially indurated
pale yellow sandstone, separated into strata by thin layers of sand.
This sandy mass is in part soft, and in part indurated, and con-
tains cavities filled with loose sand. It dips at a very small angle
in a direction opposite to the strata which contain the cane fossil,
and lies upon the ends of these strata as sand would lie that had
been thrown over them by a stormy sea. It seems no where more
than a foot thick, and is covered with limestone rubble to the depth
of two feet, upon which reposes the turf.
In this sandstone are long stalks of alcyonia, resembling chee at
the back of the Isle of Wight, but the mass in which they are found
being of inconsiderable size, I have not been able to find in it any
heads or roots of that fossil. These stalks are white like lime, and
although in general much decomposed, exhibit their cylindrical
forms very exactly, and if taken in fragments look like carious
bones.
I observed in a broken piece of the sandstone upon the horse road
already mentioned, a stalk of the alcyonium about two feet long,
and branching at one extremity. I also found among the rubbish
other fragments of stems, which must have been of considerable
magnitude,
Mr. CUMBERLAND on the Strata at Whorlbury Camp. 219
The under part of this thin bed of sandstone is stalactitical, form-
ing friable concretions of sand, dependent chiefly from the stems of
decayed alcyonia. Were it not for these alcyonia, and for the lime-
stone rubble which is found upon the surface, any one would sup-
pose this bed to be of very recent production, formed of sand and
ochre concreted by the action of the sea.
XI. Observations on the Hill of Kinnoul, in Perthshire.
By J. Mac Cuttocu, M.D. F.L.S. President of the Geological Society,
Chemist to the Ordnance, Lecturer on Chemistry at the Royal
Military. Academy, and Geologist to the Trigonometrical Survey.
[Read March 4th, 1$14.]
In transmitting to the Society the specimens from the hill of
Kinnoul which accompany this paper, I have thought it necessary
to enter into a description somewhat detailed, of appearances at-
tended with considerable interest, and involving some difficulties.
We are yet, it is to be feared, in want of a theory capable of sol-
ving all the cases which the increased activity of geological research
is daily bringing to light. It is among difficult and unexplained
phenomena that we are to seek for the stimulus which will lead us
to pursue those researches on the multiplication of which alone we
can hope to found a true system; and it is to a salutary distrust
of the all-sufficiency of any hypothesis, that we must look for pro-
tection from its paralyzing effects.
The hill of Kinnoul, from which the specimens now before the
Society were selected, has been frequently visited by geologists and
mineralogists, more perhaps with a view to the minerals which the
rock contains than for the purpose of examining those remarkable
geological phenomena which it exhibits. Except the account of it
in the travels of Faujas de St. Fond, I know not that any description
of this hill has been laid before the public. The peculiar opinions
Dr. MAc Cuiziocu on the Hill of Kinnoul. 221
of that author are well known, and I believe that in this country
it is not necessary to enter into any refutation of his conclusions.
As far indeed as the appearance of the trap rocks and their peculiar
mineralogical character are concerned, the Huttonian theory offers an
explanation better able to fulfil the requisite conditions than his
hypothesis. I shall therefore decline entering into a comparative
statement of systems so well known, or investigating the solidity
of the examples which the French geologist has adduced from
Great Britain. Although never formally discussed, the arguments
and objections are familiar to most of those who have engaged in
geological researches, and a full examination of his individual cases
would lead into a dissertation foreign to the purpose of this notice,
I may therefore briefly remark that the chief part of the hill in
question consists of trap, which, like the other rocks of this fa-
mily that alternate with secondary strata, is known in the Wer-
nerian nomenclature, by the term of floetz traf. I do not pretend
to name its rank in the several formations enumerated under this
general title, as I much doubt if the assigned characteristics are con-
stant. Ifthey are universal it will not be difficult to give it its
place in the system when I have described its features and con-
nections.
The phenomena which are most interesting in this hill render
it necessary to take a range somewhat wide before describing the
rock itself, without which we should be unable to trace its con-
nection with the neighbouring rocks and the surrounding country.
Those who are acquainted with the mineral geography of Scot-
land know that a great portion of its northern district is separated,
in many places very accurately, by a tract of breccia from the
secondary rocks which occupy its middle portion. An irregular
line drawn through Troup head, Dunnotter, Blair gowrie, Delvin,
VOL. Iv. 2F 7
ted
299 Dr. Mac Currocu 6n the Hill of Kinnoul.
Creiff, Tillycoultry, Callander, Aberfoyle, Drymen, and oiher
almost nameless places to the westward, marks the range of this
breccia, leaving on the north side all those rocks distinguished by
the name of primary, with many of those which’ bear the name of
transition, and being followed to a certain distance southward by the
usual series of sandstones and other secondary strata. In the mid-
dle of this secondary tract arises the hill of Kinnoul, forming the
westernmost part of a Jong irregular ridge which extends from the
north of Dundee to Perth, where it terminates. Through part of
this course it exhibits an abrupt elevation to the south, subsiding
northward by a more gentle declivity into the great plain of Stor-
mont and Strathmore. Its visible boundary to the south is the allu-
vial plain of Gowrie, while to the north the red sandstone and that:
breccia which accompanies or precedes the sandstone, form the only
rock for a distance of many miles, till we arrive at the mountain
schistus. I am not acquainted with the connection of this ridge at
its eastern end,
The height of Kinnoul, (that part of the ridge which I purpose
to describe) is 600 feet above the plain of the Tay, and it occupies
a length of a mile or thereabouts, exhibiting many abrupt faces in
a state of constant ruin and degradation, which have thus formed
a rapid slope at the feet of the precipices.
The rock itself contains many of the most remarkable varieties
belonging to the tribe. It will be sufficient to give a general des-
cription of them, as no purpose could be served by an attempt to
define rigidly either the spaces which they respectively occupy, or
the order which they follow, circumstances which are subject to
such variations as to obey no general rules. In some places a black
basalt may be observed, but it is every where amorphous and ap-
proaches here and there to the most ordinary kinds of compact
Dr. Mac Cuttocu on the Hill of Kinnoul. 223
greenstone. This, variety is the least abundant. It occasionally
assumes a brownish or reddish colour, retaining its original com-
pactness and uniformity of texture, and thus forming a member of
the trap family, to which no distinct name has been assigned. This
becomes at times porphyritic, containing numerous minute crystals
of felspar imbedded in a blackish or brown basis, and forming a
showy variety of trap porphyry. The felspar, as far as I have
observed, is always opaque. Sometimes the rock is both porphy-
ritic and amygdaloidal, but perhaps the greater part of the whole
hill consists of a rock merely amygdaloidal, the base of which
is either the well characterized basalt above described, or that variety
which is less marked, or else a rock intermediate between this
latter and indurated clay.
The character of the amygdaloid varies considerably according to
the substances which it contains, and these are green earth, calca-
reous spar, quartz, and chalcedony.
Green earth or chlorite, is the substancé which perhaps occurs
most frequently, and it is indeed that by which the trap of Kinnoul
is particularly distinguished from almost all the rocks of this tribe
in Scotland. The nodules vary but little in size, and although they
are occasionally met with of the bulk of a filbert, they are gene-
rally little larger than a grain of mustard. But they vary much in
colour, assuming all shades from greenish black to the brightest
-verdegris green. ‘They differ equally in texture, being sometimes
minutely powdery, at other times of a large scaly fracture, like the
chlorite which occurs in primary rocks. It is this substance which
Faujas has called steatite ; no real steatite being found in the trap
of Kinnoul, although it is common in that of the island of Sky.
When calcareous spar forms the amygdaloidal nodule, it is com-
monly invested with a coating of chlorite. ‘These nodules are
22
224 Dr. Mac Cutrocu on the Bill of Kinnoul.
generally of a small size, and of a spheroidal or ellipsoidal form.
Their fracture is crystalline, and they are often perfectly transpa-
rent, but in all cases where they are in immediate contact with the
trap they possess no external crystallized form. It is only when
in contact with quartz or agate that they exhibit an external as well
as an internal appearance of crystallization. In other words, they
appear to bear the impression of the basalt when they are in im-
mediate contact with it, while on the contrary, when in contact
with quartz or agate, they impress their forms on these. Calcareous
spar thus assists in forming a compound nodule not uncommon in
these rocks. The spar is sometimes crystallized at liberty in a
cavity of quartz or agate; at other times it is closely invested
by quartz, forming the center of a solid nodule, or is dispersed
in small crystals irregularly scattered through the whole pebble.
Both these substances occasionally retain their perfect characters,
even when in immediate contact; while in other instances the
quartz for some small distance in the vicinity of the calcareous
crystal is converted into chert or into agate.
Quartz is found among these rocks in the usual variety which it
exhibits when it is an inmate of trap. In its simplest form it is a
crust investing a cavity, and terminating interiorly in assemblages
of crystals of various sizes and of various colours, white, brown,
and amethystine. ‘The exterior quartzy crust often puts on the
character of chert, sometimes that of chalcedony ; not unfrequently -
the chalcedony appears in the form of a stalactite, of which the
several icicles are encrusted with beautiful and crowded assemblages
of crystals. These stalactites of crystals depend, as is usual in
stalactites, from the upper parts of the cavity. The nodules of
this description are of various magnitudes and often of a foot or
more in diameter, and, like the smaller ones, are shut in and
Dr. Mac Cuttrocn on the Hill of Kinnoul. 225
surrounded by the solid rock on all sides. It is more common for
the boundary of the quartz in the immediate vicinity of the trap to
be formed of various zones of coloured chalcedony. The quartz
in this case assumes a peculiar well-known aspect, and is called in
the Wernerian nomenclature, amethyst, although most commonly
of a white or watery appearance. Different zones of chalcedony
and quartz will even at times succeed each other in the same nodule.
But the imbedded mineral from which this place has acquired
its greatest celebrity, is the agate, or coloured chalcedony, with
which it abounds, but which it possesses only in common with many
other places in Scotland. The nodules of this substance vary ex-
ceedingly both in size and colour, and their general aspect is much
too well known to need any description; yet a few circumstances
respecting them deserve to be considered, as they involve difficul-
ties which it is incumbent on any general theory of the formation
of these rocks to explain. Their external surfaces, I believe inva-
riably, bear those marks of indentation by the surrounding rock
which determines their posteriority of formation, or at least their
posteriority of induration, to that of the rock in which they are
imbedded. Their internal! structure is also most commonly zoned,
with irregularities corresponding to those of the external boundary ;
but in some cases they exhibit a complication of structure, which
as it cannot be well described in words, I have ventured to repre-
sent in the accompanying sketches. In the first example, a sta-
lactite may be observed occupying a portion of a hollow cavity,
marking as in the case of the larger quartz cavities described above,
the gradual deposition of siliceous matter by infiltration.* The
change of disposition in the zones in the figures N° 2 & 3,7 seems
to be the result of a similar process, the horizontal parallel lines
* PI. 10. N° 1. + Pl. 10. N°2 & 3.
226 Dr. Mac Cuttocn on the Hill of Kinnoud.
appearing to be the stalagmite formed on the bottom of the cavity,
and proceeding from below upwards in successive additions, in a
way similar to that which may be observed in the complicated
chalcedonies of Faroe. The peculiarity observable in the fourth t
example can be explained only by a similar supposition.
Such are the circumstances of chief importance which occur in
the trap nodules, and which, although by no means limited to this
place, appear deserving of notice, on account of the intimate
relation they bear to any general theory. It is incumbent on that
hypothesis which explains one of these difficulties, to explain the
others also, or at least to require nothing which shall exclude the
means of explaining them. It is almost needless to say that I here
allude to the different explanations which the aqueous and the
igneous theories of the origin of trap have given of the imbedded
nodules. Each hypothesis has its difficulties when it refuses to
yield ground to its antagonist ; yet, 1s each perhaps incapable of
exclusively and clearly explaining the appearances in question.
The stalactitical forms which line the hollow cavities, can perhaps
have resulted only from watery infiltration, yet the existence of
the previous cavities can scarcely be accounted for by that hypothe-
sis which considers trap as a deposit crystallized from an aqueous
solution of earths.
Different substances are found occupying veins as well as nodules
in this rock; among these, calcareous spar and quartz are the most
common. Sulphate of barytes occurs more rarely, as do chert and
agate, the latter of which often exhibits the same zoned appear-
ance in the veins which it does in the nodules.
The great abundance of chlorite in this trap might have rendered
it probable that the rare mineral heliotrope was an inmate of it:
t{ Pl. 10, N° 4.
Dr. MAc Cuxiiocn on the Hill of Kinnoul. 227
accordingly I have laid before the Society some small specimens
found there by Lord Gray’s workmen in removing earth at the
foot of one of the precipices. It forms veins of different dimen-
sions in the fragments of rock, with which it is intimately united :
it is of a finer green colour than that which is found in Rum, but
none of the specimens which I procured contain the red spots for
which this mineral is principally valued. It sometimes is associated
with a green quartz, coloured apparently by the same material, the
more transparent parts having the aspect of plasma, which not im-
probably owes its colour to chlorite. I did not succeed in finding
this mineral in the face of the rock from which these specimens ap-
pear to have been detached, but among the agate pebbles there to
be seen I obtained some which present appearances illustrative of
its composition. These pebbles are frequently incrusted with a
coating of chlorite, and in those to which [ allude the chlorite
penetrates the external part of the agate to the eighth of an inch,
so as to convert the outer crust into heliotrope. I may here also
add that I have observed this mineral among the agates found in
Ayrshire, and that it occurs in the island of Mull, where it forms
spheroidal nodules in basalt, so that it is not rare in Scotland.
When I say that zeolites are not found in Kinnoul, I ought to add,
that I picked up one loose and bad specimen of red stilbite.
On the top of the great mass of trap which I have now described,
there is to be seen a portion of a bed of conglomerate, consisting
of trap pebbles imbedded in a cement of the same nature, a rock
improperly designated by the name of trap tuff. The origin of
this rock is not easily explained, but I must defer the remarks that
might be offered on this subject to some future opportunity.
The last and most remarkable circumstance occurring in Kinnoul
is that of an extensive range of those junctions with other rocks
228 Dr. Mac Cuttocu ox the Hill of Kinnoul.
which are supposed by many persons to demonstrate the igneous
origin of trap.
About the middle of the broken face of the hill a portion of a
stratum of sandstone is to be observed entangled in the mass of the
rock, and at the same time much broken and bent. But there is
nothing in its appearance so very different from the other instances
of this fact which have been frequently described, as to call for a
particular detail.
Proceeding from this point eastward another set of junctions is
seen, of which I have not met with any resemblance in other
places, and which offers some anomalous appearances. The strati-
fied rock which is here conjoined with the trap, is perfectly similar
to the best characterized graywacké slate, of a fine grain and
greenish hue. It is easily separated into flakes, and on being
broken, exhibits slender scales of mica. A remarkable change of
its aspect may be seen where it approaches the trap, and before it
comes into actual contact with it. If the weathered surface only
be examined, it shews a series of solid laminz alternating with, or
rather graduating into other lamine which have a spongy appear-
ance, or abound with open cavities similar to those of weathered
amygdaloids. ‘These cavities increase in number and magnitude
towards the middle of the spongy laminz. The same appearance
of pores or cavities is to be observed at most of the points of contact
where the graywacke is much contorted and mixed with the trap.
A good illustration of this appearance may be given by comparing
it with that assumed by the burnt micaceous schist sometimes
found in the walls of the vitrified forts, and which by the action
of the fire on some of its laminz is swelled up and thickened,
apparently from the disengagement of aeriform matter. When,
however, this stone is broken, the cavities are found to be filled by
Dr. Mac Cutxocu on the Hill of Kinnout. 929
calcareous spar, and exactly resemble those which occur in the trap
rocks themselves.
I remarked above, that the schist is often much contorted and
mixed with the trap. This mixture affords a great variety of appear-
ances, a variety so great that no limited series of specimens, nor
any drawing less than that of the whole face of the hill itself, could
give an adequate idea of them. *The accompanying sketch exhibits
one of the most general. In many parts innumerable detached
fragments may be seen imbedded in the trap, the whole of the
schist displaying a greater disorder and confusion than the sand-
stone does in any of the instances hitherto described. In a few
places another singularity may be remarked. Veins of differ-
ent dimensions, and ramifying in different directions, are to be
found traversing considerable portions of the rock, and in some
instances terminating in the schist, with which they are continuous.
As the schist graduates into the vein, its laminated texture disappears,
but in other respects there is an identity of composition between
the vein and the laminated schist, at least for a considerable space.
The same loss of the laminated texture of the schist takes place
wherever, from its proximity and intermixture with the trap, it is
materially perverted from its original even direction. In other
respects the identity of substance is here, as in the other case, pre-
served, nor is any decided line drawn to determine the disconti-
nuation of the laminated structure, either in the progress to contor-
tion or ramification. However contradictory it may appear at first
sight, that the same substance should exhibit both the character of
a laminated and bedded rock and that of a vein, the state of the
incurvated and contorted masses may perhaps by analogy assist in
solving the difficulty. It is not an unreasonable supposition, that
* Vide Plate, 11,
VoL. Iv. 2G
230 Dr. Mac Cutrocs on the Hill of Kinnoul.
a rock in a condition to be bent and incurvated, should by a peculiar
application of external force admit of that more continued pro-
longation which in certain circumstances would produce a vein.
The analogous incurvations indeed, and the evident prolongations
which take place among the laminz of mica slate, and in the con-
torted veins of granite and quartz which traverse them, offer cases of
parallel difficulty. If the solution which I have offered be incom-
petent to this purpose, it is only one more added to the numerous
unexplained phenomena which are to be found attending the
subject of geology wherever we turn our regards: for we can
then look to neither of the prevalent hypotheses for an adequate
explanation of this case; the mechanical structure of the schist as
indicated by the parallel disposition of the mica, combined with the
want of similar mechanical arrangement in the vein, offering a
difficulty to the one as great as it is to the other. I speak of a
mechanical arrangement in the schistose rocks as if it were admitted
by all, because it appears a circumstance attending on many of these
rocks, as perfectly demonstrated as any thing of which we have
not actually witnessed the creation, can be demonstrated to our
senses.
For the same reasons I speak without hesitation of the displace-
ment, fracture, and incurvation of the graywacké which is imbedded
in the trap, and in so doing it is not my wish to speak the language
of an hypothesis, but to describe a fact, in such terms as can alone
convey an adequate notion of the appearances to a mind divested
of all hypothesis. If Nature has really produced imitations of
mechanical arrangement by processes unknown to us, it is to be
wished that the mode in which they have been produced may be
shown, either by means of experiments, or by analogies drawn
from that science of which the laws regulate the great proceedings
Dr. MAc Cutiocn on the Hill of Kinnoul. 231
of Nature as they do the narrow operations of our own laboratories.
Till that be done, it is not only legitimate, but it is indispensible
for the purposes of accurate reasoning, to describe facts by their
most obvious analogies where we cannot pronounce on their na-
ture, to call that a mechanical arrangement in Nature which bears
a resemblance to mechanical arrangement in the products of art,
and to consider that only as the result of chemical action in Nature,
which is imitable by chemistry under the direction of art, or has
been demonstrated to be in other cases the result of chemical laws.
It appears then that at Kinnoul portions of schist are found
presenting an obscure appearance of connection with the red
sandstone. It also appears that this rock exhibits but a small
portion of a bed, instead of that great and extensive continuity in
which it is generally disposed. And it is further seen that this
portion is entangled and almost surrounded by a mass of rock of a
peculiar aspect, which bears no mark of stratification or of mecha-
nical arrangement, and that it is much bent and contorted, so as to
be irregularly intermixed with the unstratified mass. Lastly, it is
to be remarked, that appearances of fracture as well as contortion
occur in the stratified rock; that veins pass from it, and that frag-
ments of it are dispersed throughout the unstratified one; as far
at least as a judgment can be formed from the only view we can
obtain of the imbedded portions.
It is difficult to see on what other ground these and ee
appearances can be explained than on that of motion; the action
of the unstratified on the stratified mass, and that stratified mass
existing in two different conditions, a state of softness capable of
extension, and a state of hardness capable of fracture. Further
than this the facts visible at Kinnoul do not perhaps bear us out, and
| beyond this point it is not my design to venture, since the simplest
262
232 Dr. Mac Cuttocu on the Hill of Kinnoul.
record of facts is perhaps the most important service which can
now be rendered to geology.
Before concluding this paper I must add, that at the eastern end
of Kinnoul a sandstone breccia may be observed, apparently lying
below the trap, and similar to that which is the lowermost of the
secondary strata throughout the whole of this district.
XII. dn Account of some attempts to ascertain the angles of the Pri-
mitive Crystals of Quartz and of the Sulphate of Barytes, by means
of the reflecting Goniometer ; together with practical reasons for
presuming that the admeasurements assigned by Haiiy to several
varieties of the parallelopiped and of the octokedron are inaccurate.
By WILLIAM PHILLIPS, Esq.
MEMBER OF THE GEOLOGICAL SOCIETY,
[Read 16th June, 1815. }
Tse primitive crystal of quartz is considered to be an obtuse
rhomboid, of which the angles are given by Haity in his ‘ Tableau
comparatif, &c. as being 94° 24’ and 85° 36’: that of the sulphate
of barytes is a quadrangular prism with rhombic terminations, the
angles of which according to the same authority are 101° 32’ 13”
and 78° 27’ 47”. The results of some attempts to verify these ad-
measurements by subjecting the natural planes of the crystals of
both these substances, as well as some regular fragments of the latter,
to the reflecting goniometer, form the particular object of the pre-
sent communication.
The first attempts to ascertain by this means the angles of the
rhomboid of quartz, were made upon some minute primitive crys-
tals from Bristol: seven of these gave incidences on the one angle
varying from 94° 12’ to 94° 17’, and on the other from 85° 44’ to
85° 52’; not more than two or three agreed. But the reflections
234 Mr. W. PuILvips, on the angles of the
afforded by these crystals were not perfectly clear, probably owing
to their enclosing a multitude of very minute diverging fibres, per-
haps of the oxide of iron. Numerous attempts were afterwards
made upon some crystals obtained under the name of Bornholm
diamonds; many of which exhibit, on the primitive crystal, the
planes of the modifications producing the pyramids and the prism,
not in a very advanced state; the measurements they afforded were
much the same as, and by no means more regular than, those ob-
tained from the primitive crystals from Bristol.
I next carefully examined about 300 very small, brilliant, and
colourless crystals of which I became possessed under the name of
Gibraltar diamonds, and selected a large number presenting the
most perfect reflections. These crystals generally shew both pyra-
mids, separated by a very short intervening prism. But even those
that were found to reflect the best, did not all present similar
results.
Several of these however afforded perfect co-incidences of 94°. 15’
on the one angle, and 85°. 45’ on the other. Two of the seven
crystals from Bristol, and two or three from Cornwall, with brilli-
ant reflections, gave exactly the same admeasurements: and since
these are the only incidences that were found to agree, I am in-
duced to suppose that they approach, if not actually constitute,
the true value of the angles of the primitive rhomboid of quartz.
It will be observed that the former of these differs from that given
by Haiiy, in being 9’ less; the latter, in being 9’ more. It seems
requisite to add, that among the very numerous crystals that I
have attempted to measure by means of the reflecting goniometer,
not one has afforded results agreeing with Hauy..
From among several hundreds of detached crystals of the sul-
phate of barytes, eight were selected, which afforded reflections
~
Primitive Crystals of Quartz, and the Sulphate of Barytes. 235
so perfect, that the expectation of actual agreement in the admea-
surement to be obtained from them, naturally arose; but in this I
was disappointed on finding them to vary on the one angle from
101°. 25’ to 101°. 51’; and on the other, from 78°. 10’ to 78°. 28’.
This want of co-incidence in the admeasurements obtained from
crystals which, on account of their brilliancy, seemed unexception-
able, induced me to submit to the reflecting goniometer some
cleavages made in the direction of the primitive planes, and selected .
with the utmost care. Six of these agreed perfectly in affording
on each of the acute angles of each fragment the incidence of
70°. 18’, and on each of the obtuse angles that of 101°. 42’; the
former being 9’. 47” less, and the latter, in being 9’. 47” more,
than the value assigned to these angles by Haity.
This remarkable agreement afforded by the cleavages of the sul-
phate of barytes, induces regret that it is not in like manner practi-
cable to obtain regular fractures of quartz. The evidence above
cited in regard to the difficulties attending the measurement of that
substance, by means of the reflections afforded by the natural planes
of its crystals, tend, it must be owned, to render it somewhat un-
certain whether the only co-incidences obtained, viz. those 94°. 15’
85°. 45’, are the true angles of its primitive rhomboid; but the
co-incidences given by the fracture of the sulphate of barytes, seem
to authorize the conclusion that the true value of the angles of its
primitive crystals are 78°. 18’ and 101°. 42’.
It would not perhaps be reasonable to draw, from evidence rela-
ting only to two substances, the inference that the actual value of
the angles of mineral substances in the general cannot by any means
“be obtained by admeasurements attempted upon the natural planes
of their crystals. The difficulties attendant on many of them will
be found to be very great; in regard to some they seem insur-
236 Mr. W. PaiLvips, on the angles of the
mountable. Of a very large number of crystals of the red oxide
of copper in my possession, some hundreds of which were se-
lected on account of their extraordinary brilliancy, solely with the
view of subjecting them to the reflecting goniometer, I have not
been able to find a single crystal of which the primitive planes are
adapted to its use. |
The attempt to measure the angles formed by the meeting of the
primitive planes of the red oxide of copper, may reasonably be
supposed to have been made only for the sake of corroborating the.
results of calculation. ‘These results cannot perhaps be doubted,
when it is considered that the primitive crystal of this substance is
the regular octohedron, which is often found to pass into the cube;
for the angles of the one being known with certainty, it follows
that those of the other may be calculated with precision. This
observation will apply to all those substances which have for their
primitive crystals, either of those solids, or the rhomboidal dode-
cahedron, the regular tetrahedron, or the hexahedral prism.
But there are many forms of primitive crystals, included under
the term parallelopiped (amongst which are those of quartz and the
sulphate of barytes,) as well as several varieties of the octohedron,
both acute and obtuse, which do not, with the same ease, seem
susceptible of equal certainty in the determination of the value of
their angles. Iam induced to believe that many, if not most, of
these, which have already been given by Haiiy, will be found to
demand revision.
As it may be expected that reasonable cause should be shewn
for doubting authority so eminent, I shall briefly subjoin the
reasons that have principally led me to adopt this opinion. |
The first step towards ascertaining the value of the several angles
at which the numerous planes of crystals meet each other, is alto~
Primitive Crystals of Quartz, and the Sulphate of Barytes. 23'1
gether a mechanical operation dependent on the skilful use of the
goniometer; and for this purpose doubtless brilliant and well de-
fined crystals have been selected. Having arrived at the admeasure-
ment of some one prominent angle, by means of the goniometer
in common use, it can scarcely be doubted that its value has been
assumed as a basis on which to calculate the rest. This, there is
reason to believe, was the process adopted by Haity in regard to his
determination of the angles of the primitive crystal of the sulphate
of barytes, which he has given to seconds, and which the common
goniometer will not indicate. It must be obvious that the perfect
fidelity of this preliminary mechanical determination is most es-
sential.
It is no trivial argument against the accuracy of this practice,
that those who are the most skilful in the use of the common
goniometer, have differed in the results obtained from the same
substances. But, even were it possible to depend upon the accuracy
of the instrument, and upon the skill of the hand using it, there
seems much reason for doubting whether the planes of such crys-
tals as are best adapted to its use can be relied on. I allude of
course to such as are of considerable dimension. These, when
submitted to the reflecting goniometer, rarely agree with each
other; and the measurements they afford almost always differ very
considerably from those obtained upon small crystals ; which much
more frequently give similar results, but which are too minute, as
it seems to me, for the accurate use of the common goniometer.
The difficulties already described as having attended my nume-
rous attempts to verify the admeasurements of Haiiy in regard to
the primitive crystals of quartz and the sulphate of barytes, belong
not to the crystals of these two substances only. I have found
these difficulties to exist in different degrees in respect to more than
VoL. Iv. Qu )
238 Mr. W. Puivuips, on the angles of the
twenty others, of each of which I possess very numerous isolated
crystals. Amongst these, the red oxide of copper already men-
tioned is one, though of comparatively little importance ; because,
as the real value of the angles of the cube, which it occasionally
assumes, are known, the rest may be calculated with precision.
But there is still another circumstance which forcibly shews the
great difficulties attending the accurate admeasurement of the angles
formed by the meeting of the natural surfaces of crystals, by sub-
jecting those surfaces to either goniometer. It is not often found
that the best selected afford incidences corresponding with the
results obtained by calculation, even where we must be assured that
calculation may be relied on; as is the case in respect. of all those
substances which assume the cube, the regular octohedron, the
rhomboidal dodecahedron, or the hexahedral prism. The angles
formed by the meeting of the planes of these solids are known, yet
rarely do the best selected crystals accurately afford the admeasure-
ments which belong to them in their perfect state. It is not suf-
ficient that they approximate ; they should be precise.
The foregoing are my principal reasons for adopting the belief
that many of the determinations of Haiiy in regard to the ad-
measurements given by him of the primitive crystals comprehended
in the term parallelopiped, and of the numerous varieties of the
octohedron, will be found inaccurate. It is probable that the
reflecting goniometer will render service to science by detecting
some of the inaccuracies incident to the use of the common go-
niometer.
The accuracy of which the reflecting goniometer is capable,
requires, for the reasons above assigned, great patience and per-
severance in measuring the angles of crystals on their natural
planes; and the chief, if not the only, difficulty attending its use,
Primitive Crystals of Quariz, and the Sulphate of Barytes. 239
is the finding of crystals that are adapted to it. It is requisite not
only that their planes should be brilliant, but also that the image of
the line or bar reflected upon them should be perfectly defined ; its
edges should be seen with an exactness which they who have not
. given attention to the subject will scarcely believe to exist on sur-
faces so small. No reliance can be placed upon a solitary ad-
measurement taken upon the natural planes of one crystal, however
brilliant and perfect they may appear; it is essential that several
should be found to exhibit a perfect agreement, before it can be
assumed that the actual value of any angle has been obtained.
From one crystal of quartz, nearly perfect at both terminations and
affording pretty clear reflections, I obtained six admeasurements of
the same angle from its various planes. One of 94° 9’, another
of 94° 12’, a third of 94° 16’, and three of 94° 11’. I did not
discover one crystal whose planes were sufficiently perfect to enable
me to obtain corresponding measurements from plane to plane,
around it.
It cannot however, be doubted, that much of the labour attend-
ant on the use of the reflecting goniometer in the measuring of the
angles of crystals on their natural planes, will be spared, and that
the results will be much more satisfactory, because more accurate,
whenever cleavages can be obtained sufficiently brilliant for its use.
In almost every instance in which I have tried it upon the planes
produced by good fractures, the success has been complete. The
ereat value of this instrument, which may be used with readiness
and ease, demands the attention of every one who has the slightest
pretension to crystallographical research. I feel much pleasure in
adding an instance of the accuracy of which it is susceptible. Hav-
ing seen in some periodical publication, a notice that Dr. Wollaston
had discovered differences in the value of the angles of the primi-
2H 2
240 Mr. W. PHILLiPs, on the angles of, ec.
tive rhomboids of the carbonate of lime, the bitter-spar, and the
brown-spar, which had previously been considered to be alike, and
conceiving them to be erroneously quoted, as in fact they were, I
submitted to the reflecting goniometer some cleavages of the two
former, not having a portion of the latter adapted to its use. I
afterwards called on my friend Arthur Aikin, Esq. who shewed me
an account of the exact admeasurements obtained by Dr. Wollaston,
and had the satisfaction of convincing him that those obtained by
me perfectly coincided therewith.
I possess thirty-eight varieties of crystals of quartz, resulting
from the combinations of eleven modifications on the primitive
rhomboid ; and of the sulphate of barytes I have one hundred and
thirteen varieties, the result of eighteen modifications of the primi-
tive crystal; the former are principally foreign, the latter chiefly
from the north of England.
XII. On the measurements, by the reflecting Goniometer, of certain
primitive Crystals; with observations on the methods of obtaining
them by mechanical division along the natural joints of Crystals.
By WILLIAM PHILLIPS, Esa.
MEMBER OF THE GEOLOGICAL SOCIETY.
[Read 6th December, 1816. ]
In a communication read before the Society about the middle of
last year, I detailed some reasons for concluding that the angles of
some primitive crystals included in the terms parallelopiped, as well
as some varieties of the octohedron, had not been accurately ascer-
tained. Since that time, further attention to the subject has con-
firmed those observations. I proceed to lay before the Society the
results of investigations in regard to ten other substances, two
or three of which have been measured by the assistance of the
reflecting goniometer only upon their natural planes, on account
either of their not yielding to mechanical division with sufficient
freedom, or not yielding to it at all. The rest have been fractured
with exactness enough to allow the use of that instrument ; and for
that reason, the results allow of more complete corfidence, than if
there had been a necessity for relying on their natural planes.
It would have spared me much time and difficulty, if to the other
labours of the Abbe Haity and the Count de Bournon, they had added
some account of the means by which the mechanical division of
949 Mr. WILLIAM PHILLIPS on the
each substance may be most readily attained. Concluding that the
same difficulties are felt by others, I shall add some remarks on that
subject, in regard to such of the substances as I have been able to
cleave with regularity, presuming that it may tend to render the
way more easy for those who may desire to attain the same object.
It must be obvious that very different means have been resorted to;
for no one will imagine the same to be applicable to the sulphate
of barytes and the sapphire: one of them soft, and yielding to
mechanical division with the utmost ease; the other, the hardest of
all the earthy minerals, and splitting only by the application of
great force, and even then, not without much difficulty and perse-
verance in more than one direction. Still further remarks will be
needful in regard to one of the substances, the sulphate of lead,
since the mechanical division it affords has necessarily led me to
differ from the Abbe Haity and the Count de Bournon, as to the
form of its primitive crystal.
The following pages would not have been offered to the notice
of the Geological Society, but for such reasons as belong to the im-
portance of determining with precision not only the forms, but the
measurements of the angles of primitive crystals. If it should be
thought that it is assuming too much, to differ from authors so
distinguished as the Abbé Hatiy and the Count de Bournon, 1 beg
to offer the same apology as was offered by the latter for differing
from the former in the same respects. ‘The attainment of truth is
the great object that every man ought to propose to himself, who
has any pretension to science.’ * |
Such of the figures in the accompanying drawing { as suited my
purpose were copied from those of Haiiy, and when compelled to
alter the form, the letter by which he designates each plane, has
been studiously retained for the more ready reference to his works.
* Catalogue, p. xvii. + Pl. 12.
Measurement and Cleavage of certain Primitive Crystals.. 243
Nothing having been said in my papers on the oxide of tin,
and the sulphate of barytes and quartz, on the mode of cleaving
them, they are now placed in the following table at the head of the
ten substances forming the particular objects of this communication,
chiefly to allow the opportunity of saying a few words on the
subject of splitting them.
Measurements.
References to Plate 12.
Substance. Primitive Crystal. According to
Oxide of Tin
which the common base of
the pyramids is square.
Haiiy.
Fig. 1. PonP
An obtuse octohedron of
67° 50!’
P on the opposed
plane over the apex
¥I2?- 10!’
Sulphate of
Barytes
A right prism, with
@ , ”
rhombic bases. 101° 32’ 13
101° 42’
Fig. 2. M on M
M on the adjacent
plane, over the
edge A.
Haty
78° 27' 47' 78° 18°
Quartz
Fig. 5. PonP
P on P’
94° 15°
85° 45’
A slightly obtuse rhom-
boid. Haiiy. R
85° 36’
Zircone
the common base of the
pyramids is square. Haiy.
Fig. 1. P on P 82° 50’
An obtuse octohedron; ‘
P on the opposed
plane over the apex
A right rhomboidal prism
Haily.
Staurotide
A.
Anatase
the common base of the
pyramids is square. Haiy.
An acute octohedron ;
f Fig. 4. P on P
Specuiar Iron
A slightly acute rhom-
boid. Haiiy.
Fig. 3. P on P 87° 9!
92° 51’
An oblique rhomboidal
prism. Hay.
iopside '
Diggs Hig. 6. MonM B19 42!
M on the adjacent;
plane, overthe edge
244 Mr. WILLIAM PHILLIPS on the
easurements.
Substance. Primitive Crystal. References to Plate 12. | According to
Cyanite An oblique prism of
which the plane P is very f Fig. 7 M on T
nearly arhomb. __Haiiy.
M or T on the ad-
jacent plane, over
the edge A.
Corundum A slightly acute rhom- :
boid. Haiiy & Bournon. ; Fig. 3. Pon P
Pon’
Sulphate of A right prism with
Strontian |rhoinbic bases.
M on the adjacent
plane, over the edge
A.
Lead the common base of the plane over the
pyramids is rectangular. apex
Haiiy. M on M
P on its opposed
plane over the
apex
P on P
Carbonate of | Anoctohedron, of which ; Fig. 8. Mon the oer thet
A rectangular tetrahe-
Bournon.
P’ on P’
PonP
Sulphate of | A rectangular octohe-
Lead dron. Haily.
Aright tetrahedral rhom-
boidal prism with rhombic t Fig. 11. P on P
bases. Bournon.
i Fig. 9.
P on the adjacent
plane over the edge a.
A right prism Bhai :
rhombic bases. mp. Fig. 13. Pf on P
P’ on the adjacent
plane over theedge a} . . . oe ef ROBE TA
Oxide of Tin.
Pl. 12. sciigdls. |
The crystals of this substance admit of cleavage parallel with all
_the sides of the common prism, and of its diagonals, as well as the
faces of the primitive octohedron, which is obtuse. The first is
Measurement and Cleavage of certain Primitive Crystals. 245
more readily obtained than the second, but it is extremely difficult
to effect it parallel with the primitive planes. Yet having sacrificed
very many crystals in the pursuit of this object, I possess several
fragments in each direction, having brilliant surfaces. The hardness,
and at the same time, the brittleness of the substance were obstacles
to the discovery of its natural joints, which it was difficult to find
the means of overcoming ; but, after resorting to various expedients,
I found the employment of a pair of steel pincers the most certain
mode of effecting it. Being sharp, with edges about an inch long,
they seize on the square prism, equally throughout its whole length ;
and, if the edges be carefully placed along the center of the prism, or
parallel thereto, it splits, by considerable pressure, shewing planes
parallel to two of the four sides of the prism. By the same means,
it may again be split at right angles. In the endeavour to obtain
cleavages in the directions of the diagonals of the prism, I found it
impossible to lay hold of the sharp edges lengthwise, because the
edges of the instrument were also sharp ; and therefore took off the
pyramid as nearly at right angles with the prism as possible, pro-
ducing a plane, parallel to which it was requisite to procure another
at the other end of the prism: applying then the pincers to
these parallel planes, and in the direction of the diagonal, the prism
sometimes yielded in that direction. But the crystals of tin are
most readily split according to their natural joints, by placing them
for some time in a common fire or a smith’s forge; a slight blow
with a hammer afterwards reduces them into numerous small pieces,
and amongst such, I have found fragments in all the directions
above mentioned ; indeed this was the only means I could devise
for obtaining them parallel with the faces of the primitive octohe-
dron. The subjecting of the crystals to the action of heat, has
however some disadvantages: not only are the fragments less bril-
VOL. Iv. 21 |
246 Mr. WiLL1AM PHI LuriPs on the
liant than such as are obtained by the pincers, but it appears that
the tendency of heat to separate the natural joints has also the effect
of cracking the crystal in other directions in which there is no
regular cleavage; so that, if the blow of the hammer be not gentle,
the consequence commonly is that the crystal is reduced -almost to
powder.
Sulphate of Barytes.
Fig. 2.
In almost every flattish crystal of considerable dimension. its
natural joints are apparent when holding it between the eye and
the light. If not, a slight blow will cause them to appear; and if
by design or accident, the crystal fall flat upon the floor, it imme-
diately breaks parallel with some of the planes of the primitive form
and frequently even into the form itself, which is, a right prism
with rhombic bases. It follows that a substance whose laminz are
held together by so slight a crystalline polarity, may be cleaved or
split by various means; the same may be observed of the fluate
and carbonate of lime, the crystals of which likewise generally
present indications of their natural joints. But the most certain
and least injurious mode of cleaving these substances is, by placing
‘the crystal, if it be large, on a table; when, if the edge of a sharp
and strait knife be placed in the direction of the natural joints, a
slight blow with a hammer on the back of the knife readily separates
-the crystal along them. If on the contrary the crystal be small, the
-object is perhaps more easily attained by the assistance of a sharp
penknife, while holding the crystal between the finger and thumb,
more especially if it be very flat and thin ; in which case, a slight
Measurement and Cleavage of certain Primitive Crystals. 247
blow with the hammer, even if the edge of the knife be precisely
along the natural joints, is apt to have the effect of splitting it in
various directions.
Quartz.
Figen.
Since the time of presenting to the notice of the Geological
Society, the memoir on the measurements of the angles of the
primitive crystals of quartz and the sulphate of barytes, several other
crystals of quartz with perfectly reflecting planes have corroborated
the opinion therein stated, that the angles of the primitive rhomboide,
which is slightly obtuse, are 94° 15’ & 85° 45’; which have also
been further strengthened, and I may say confirmed to be their
true value by co-incidences obtained by means of the reflecting
goniometer from some fragments, exhibiting brilliant planes parallel
with those of the rhomboide.
Crystals of quartz do not often present clear indications of their
natural joints. By consulting Haiiy, Traité Pl. XL. fig. 3. it will
be observed that the primitive rhomboide is so situated in a dode
cahedral crystal, that six of the twelve planes of the latter figure
are alternately parallel with the primitive planes; the other six
being the result of a modification explained by fig. 2 of the same
plate. If therefore we would cleave a,prismatic crystal of quartz,
we are by the above circumstance assured, that by striking the
prism diagonally and parallel with any plane of the upper or lower
pyramid, it will be parallel with one or. other of the planes of
the primitive rhomboide, and, of course, in the direction of its
natural joints. It will be well to attend to this observation, if
212
248 Mr. WILLIAM PHILLIPS on the
if we would methodically seek to obtain the nucleus. By following
this plan, I have occasionally succeeded by the assistance of the
pincers, or by sharply striking a piece of steel long enough to
extend across the surface, with its edge placed on the quartz in
the direction of its laminz. ‘That neither of these plans often
succeeds, and I know of none more effectual, is to be attributed to
the great brittleness of the substance, which renders it liable, even
when struck in the direction of its natural joints, to present frag-
ments wholly irregular, or in various degrees approaching the
conchoidal form. Quartz may however, though with still greater
difficulty, be split in two or three directions which are not parallel
with the planes of the primitive rhomboide.
Zircone.
Fig. 1.
Several substances, not essentially differing in composition cr in
their crystalline form, are by Hatiy arranged under the general
term zircone. ‘Their primitive crystal is described in the Tableau
Comparatif, as an obtuse octohedron with square bases admitting
of regular fracture parallel with sections passing through the apices,
and through the centers of the edges D. D. The jargoon of Ceylon
does not admit of being split with the same ease as the hyacinth of
France, of which I have obtained and possess regular cleavages in
the directions mentioned by Hatiy, and also parallel with sections
that would divide the octohedron into four parts by passing along
all the edges of both pyramids.
The fractures in the direction of the primitive planes were most
difficultly obtained, and though numerous, are not sufficiently
Measurement and Cleavage of certain Primitive Crystals, 249
brilliant for the use of the reflecting goniometer; that instrument
therefore, in regard to this substance, has been used only to measure
the angles by means of the reflections of the natural planes of the
crystals; but as the hyacinth of France is always too much water-
worn to present those well defined reflections which alone can be
relied on, and which frequently occur on the smallest and most
transparent crystals of the jargoon, I first depended on the latter,
but have since been enabled by the examination of a large quantity
of hyacinths, to find some crystals which, though dull, afford the
same results.
These results differ from those obtained by Hai, no less than
one degree and a half, which caused me to measure over again the
whole number of crystals, but without discovering any error. The
incidence of Pon P is given both in the Traité and Tableau Com-
paratif as 82° 50’, leaving of course the incidence, of P on the
opposed plane over the summit 97° 10’, as the complement. But
as the crystals of jargoon in my possession, rarely exhibit both
pyramids, and never sufficiently brilliant to be relied on, I have
been compelled to depend on measurements obtained on the plane
P and the opposed plane over the apex. Clear reflections agree in
five instances in affording 95° 40’, in two or three 95° 35’, and in
one instance 95° 30’; while the only incidence of P on Pis 84° 15’,
being five minutes short of what I conceive to be the true value of
the angle, viz. 84° 20’. Two fragments exhibiting planes parallel
with the faces of the primitive octohedron, but not sufficiently
bright for the use of the reflecting goniometer, afford by that in
common use, an angle of about 95° 40’; two others of about
84° 20’.
I have now stated the reasons which induce me to assume the
true measurement of P on P to be one degree and a half greater
250 Mr. WILLIAM PHILLIPS on the
than that assigned to it by Hatiy. However it must be allowed
that, on taking into consideration the circumstances that all the
brilliant crystals did not agree in yielding the same results, and of
my being compelled for want of brilliant fractures, to depend on
the natural planes, it is possible that the measurements on which
I rely may not be absolutely correct.
Like inost other hard and brittle substances, the hyacinth most
readily yields to the pincers.
Staurotide.
Fig. 2.
In regard to this substance also I rely on the measurements ob-
tained by means of the reflecting goniometer on the natural planes.
The form of the primimitive crystal is a right rhomboidal prism
(fig. 2) of which the admeasurement of M on M is given by Haiiy
as 129° 30’. Two of the only three crystals that were submitted
to that instrument agree in affording, each two measurements of
that angle 129° 20’, and each also two of M on the adjacent plane
over the edge A 50°40’. The other affords one of 129° 20’; only
two of its planes give clear reflections; which on the faces of the
other two crystals were remarkably clean and well defined. These
crystals are from St. Gothard.
Anatase.
hie.
The form of the primitive crystal of anatase is an elongated octo-
hedron of which the common basé is square. Of nine isolated
crystals in my possession only two are sufficiently brilliant for the
Measurement and Cleavage of certain Primitive Crystals. 251
use of the reflecting goniometer; these agree in the incidence of
Pon P as 136° 47’, given by Haiiy as 137° 10’. These crystals
are very small, and as they differ from each other, and exhibit the
planes of some modifications not hitherto described, I have not
found courage to run the hazard of sacrificing them, incidental to
the attempt to cleave them in the direction oftheir natural joints.
Specular Iron,
Fig. 3.
This substance, a variety of the fer oligiste of Haiiy, may be
split in the direction of its natural joints when held in the hand,
by means of the pincers, care being taken to place their edges
parallel with the primitive planes, which are generally observable
on the edges of the crystals from Elba. In this manner I have
procured six fragments, one of them the primitive rhomboide,
which is slightly acute, nearly complete, and all of them having
two or more planes sufficiently brilliant for the use of the reflecting
goniometer, and all afford the measurements of 86° 10’ or 93° 50’,
some of them both; the former being 59’ less, the latter 59’ more
than the measurements obtained by Hatiy on the natural planes by
means of the common goniometer. The perfect agreements afforded
by the fragments, have so far satisfied me that the results are the
true value of the angles of the primitive rhomboide, that I have
‘not attempted to measure its angles by means of the reflections to
be observed on the natural planes, which are often very brilliant ;
for experience has confirmed me in the opinion that as the natural
planes do not often yield results agreeing amongst themselves, they
cannot be relied on with the same confidence as the planes obtained
252 Mr. WILLiAM PHILLIPS on the
by cleaving crystals in the direction of their natural joints, which
almost always agree; when they do not, the cause may always be
discovered by the observer.
Diopside.
Fig. 6.
The crystals of this substance in my collection are not brilliant
enough on the natural planes to give perfect reflections. On apply-
ing the pincers to one of them parallel with the planes of its prism,
I found that it did not yield in that direction, but in that of its
diagonals. The only three fragments submitted to the reflecting
goniometer agree in affording the measurement of M on M, 87° 5’;
being 37’ less than that obtained by Hatiy on the natural planes.
Two of these fragments also yield the complementary incidence of
92° 55’; being the angle of M on the adjacent plane over the edge A.
The diopside is considered by Haity to be a variety of the py-
roxene. In the attempt to cleave the latter substance, I have not been
able to overcome the difficulties it presents. One crystal yielded to
the equal pressure of the edges of the pincers, but did not present
brilliant surfaces in more than one direction. It may therefore be
true of the pyroxene as of many other minerals, that its cleavage is
more difficult in one direction than another; but the circumstance
just mentioned may perhaps in this instance be attributable to the
heat which this crystal had the appearance of having undergone.
Two others, of considerable external lustre, fell into powder under
the pressure of the pincers. ‘Two crystals presenting clear reflections
on the natural planes, gave the incidence of M on M, one 86° 55’,
the other 87° 5’. Two others, also brilliant, gave the value of M
on the adjacent plane over the edge A, each 93°.
Measurement and Cleavage of certain Primitive Crystals. 253
Cyanite.
Fig. 7.
On submitting some brilliant crystals to the reflecting goniometer,
it became evident that no reliance could be placed on their natural
planes. The form of the primitive crystal 1s an oblique prism.* The
incidence of Mon T, given by Haiiy as 106°6’, varied very much ;
106° 6’, 106° 10’, 106° 20’.
This substance is considerably hard and brittle ; but in the attempt
to cleave it in the direction of its natural joints, the same means ‘did
not succeed that usually does with other substances possessing those
characters. The pincers always bruised the laminz in separating
them, which was fatal to precision. ‘The most effectual means to
avoid this, I found to be that of placing the crystal on a table, and
supporting its under part in such a manner that the lamine to be
separated should be perfectly at right angles with the table. A sharp
penknife then being placed in the desired direction, a smart blow
with a light hammer usually produced the effect. Several fragments
procured in this manner agreed in the incidence of M on T,
106° 15’, and that of T on M on the adjacent plane over the edge
A 73° 45’; the former being 9’. more than the measurement obtained
by Haiiy from the natural planes by means of the goniometer in
common use.
A regular fracture in the direction of the terminal planes of the
primitive crystal is not so easily obtained as those parallel with the
lateral planes. I obtained one considerably brilliant, but not suffi-
ciently so for the use of the reflecting goniometer.
VOL Iv. 2k
254 ‘. Mr. WitzirAmM Puizuires on the:
Corundum.
Fig. 3.
The form of the primitive crystal of corundum is a slightly acute
rhomboide. From among the numerous fragments in my possession,
two were selected, in the form of the primitive crystal, which, from
the unusual splendour of some of their planes, gave reason for sup-
posing they might be adapted to the use of the reflecting gonio-
meter; one of these yielded the incidences of 86° 18’ and 93° 45”,
The other one incidence of 94° 3’. These angles are given by Haiiy
86° 38’ and 93° 22’, and by the Count de Bournon as 86° and 94°.*
In searching for the cause of so great difference in fragments of
the same substance, it occurred to me that it arose from the nature
of the substance itself, or rather from the peculiar aggregation of its
laminz. Though the corundum is one of the hardest substances in
nature, it is well known that its lamine may be separated without
the application of any violent mechanical force, and in some speci-
mens, even with ease. Hence it occurred to me that this must be
the consequence of some foreign substance being interposed between
the layers of the substance itself; and that, if this were the case, it
could not be expected to give coinciding measurements, because of
the doubt whether the interposed body could be disposed with perfect
regularity. There seemed therefore no hope of attaining the desired
object, unless the specimen could be reduced into lamine so ex-
tremely thin that there should remain nothing but. corundum.
Finding that this was not to be expected from the common varieties,
I sought, and fortunately found a small fragment, nearly colourless
'* Phil. Trans. 1802.
Measurement and Cleavage of certain Primitive Crystals. 255
and transparent, and bearing at first sight as much the aspect of
quartz as of corundum. From this, I succeeded in obtaining, among
others, four very minute portions with brilliant and perfectly re-
flecting planes. These were procured by the assistance of the
pincers; but it must be confessed that, as the directions of the
natural joints were not at all visible, it was more by chance than
regular design that they were obtained at all. Owing to the
extreme hardness of the substance, I found it requisite, after placing
the specimen in the pincers, to envelope it and them in a piece of
cloth, to prevent the escape of the fragments; as the force which
it is requisite to use would otherwise have caused them to fly in
various directions. ‘The same mode was for similar reasons pur-
sued in regard to the oriental ruby and the sapphire: the latter
may be cleaved with the utmost beauty and regularity in one
direction ; in the others it is difficult.
One of the fragments of corundum yields the measurements of
86° 4’ and 93° 56’; the other three, each 86° 4’. Two minute
portions of the sapphire give each 86° 4’; another 93° 56’. One
fragment of the oriental ruby yields 86° 4’. In the whole seven
corresponding measurements of 86° 4’ and two of 93° 56, which
therefore I consider to be the true value of the angles of the primi-
tive rhomboide. ) - fees
Sulphate of Strontian.
Fig. 2.
- The form of the primitive crystal of the sulphate of strontian is’
considered to be a right prism with rhombic bases. Its angles are,
according to Haity, 75°. 12’. and 104°, 48’. On submitting several
crystals with perfectly reflecting planes to the goniometer, I found
2x 2
256 Mr. WILLIAM PHILLIPS on the
the measurements of the obtuse angle vary from 103°. 45’. to
104°. 17’, the greater part of them being 31’ less than that ob-
tained by Haiiy, as I presume also on the natural planes.
These disagreements induced me to attempt the splitting them
parallel with the natural planes of the prism ; for which purpose
those from the neighbourhood of Bristol, being flat, nearly trans-
parent, and almost always exhibiting the directions of their natural
joints, seemed well adapted. But the result was not at first equal
to the promise. For though they were readily split, the fragments
first obtained yielded results agreeing scarcely better than those pro-
cured from the natural planes; the cause of which, not being then
able to discover, I was compelled to forego the hope of determin-
ing the point by such means. On resuming these fragments some-
time afterwards, their examination induced the suspicion, that the
differences in their results under the reflecting goniometer, arose
from the numerous crevices observable, when a fragment was held
between the eye and the light, in almost all the flat crystals from
the neighbourhood of Bristol; but which were no doubt increased
in the fragments just alluded to by the manner of cleaving them ;
not having then discovered the best mode of effecting it. I deter-
mined therefore to reduce these fragments, until small portions with
splendid surfaces should be obtained, nearly or wholly free from
any crevice. And as the crystals are at once soft and very brittle,
the utmost care was requisite. When laid on a table, with the edge
of a sharp penknife placed in the direction of their natural joints,
the pressure or slight blow requisite to divide the laminz, injures
the crystal by increasing the crevices. The only way in which I
could succeed was by holding the specimen flat between the left fore-
finger and thumb, and applying without much force a sharp pen-
knife to the thinner edge of the tabular crystal, pressing at the same
Measurement and Cleavage of certain Primitive Crystals. 257
time the nail of the right thumb in the opposite direction. But if
the blade of the knife be not held perfectly level with the direction
of the natural joints, it is apt to injure the brilliancy of the plane it
produces. The terminations of the crystals being in general most
free from crevices, and most transparent, are therefore best adapted
to the purpose I have been describing.*
Five very small fragments procured in this manner, yielded by
the reflecting goniometer, co-incidences on the obtuse angle of 104°,
and one of 76° on the acute angle of the prism; the one being 48’
less, the other 48’ more than the measurements obtained by Haiy.
A prismatic crystal from Sicily, having the primitive planes
brilliant at one end, gave the incidence of 104°. and planes ob-
tained by fracture at the other end, gave the same result.
Carbonate of Lead.
Fig. 8.
The primitive crystal of the carbonate of lead is, according to
Haiy, a rectangular octohedron, measuring one way over the sum-
mit of the same pyramid (P on the opposed plane) 70°. 30’; the
* Many other substances also possessing the characters of brittleness and softness at the
same time, may be likewise split while held in the hand, with the greatest success. Other
substances yield best to the same mode, for other reasons. Blende is one of these.’
It may he cleaved in so many directions, that if attempted to be split by means of a blow
on the back of a knife whose edge is placed parallel with the natural joints, it is most
probable that a fracture will ensue, which, though in the direction of the lamine, is not
in the desired direction. A specimen of no particular external form, but internally
Jaminated with great regularity, and about an inch and a half square, and half an inch
thick, lately yielded me, I believe, aJl the forms into which blende can be cleayed, and
even duplicates of them. Haiiy considers its primitive form to be a rhomboidal dodeca-
258 Mr. WILL1AM Puituips on the
other way (M on the opposed plane) 62°. 56’. The Count de
Bournon however considers the primitive crystal to be a rectangular
tetrahedral prism with square bases. This determination arose on
his part from having cleaved in directions parallel with the planes
of that solid, some crystals in the form of square laminz, which
are often extremely thin, and which always yielded in those di-
rections. These crystals, he adds, are found in Derbyshire, in the
Bannat, and in Siberia.*
From an amorphous specimen of this substance I succeeded in
extracting a solid in the form of an octohedron almost entire, and
having more or less of every plane brilliant enough for the use of
the reflecting goniometer. The results of measurements taken in
the same directions as those given by Hatty were, for the first
71°. 40’, being 1°. 10’ more; and for the second, 62°. 42’, being
14’ less; and not only did this fragment yield each of these mea-
surements twice, but also the complementary numbers of 108°. 20’
(P on P) and 117° 18’. (M on M), each also twice. Several
other fragments gave perfectly coinciding results.
This substance may be split with about equal ease by the assist-
ance of a sharp knife, whether it be held in the hand or placed on
a'table; provided the blade of the knife be carefully placed in the
direction of the laminz, and the back gently struck by a light
hedron, its substractive crystal an obtuse rhomboide, and its integrant molecule an irre-
gular tetrahedron. I obtained solids not only in these forms, but also others in the form
of an octohedron of 90° over the summit, and of a plane of one pyramid on the adjacent
plane of the other, and of 120° of one plane of either pyramid, on the adjacent plane of
the same pyramid; I procured also others in the form of an acute rhomboid of 60° and
120°. These measurements were obtained by means ‘of the reflecting goniometer, which
also gave those of the obtuse rhomboid 60° and 120°, which by Haiiy, are said to be
70°, 31’. 44” and 109°. 28’. 16”. Hence blende may be split into five different solids,
* Catalogue, p. 339,
Measurement and Cleavage of certain Primitive Crystals. 259
hammer. Instead of a table, however, I frequently place the crys-
tals of such substances as may be best divided by a blow, on a slab
of steel, polished on one side for the sake of a perfectly level sur-
face, which is advantageous because the resistance given by steel is
greater than that of wood. A lighter blow is therefore effectual,
and hence there is less danger of cracking the crystal in directions
opposed to its natural joints,
Sulphate of Lead. '
Fig. 940; 11,:12, 13.
The form of the primitive crystal of this substance is considered
by Haiiy to be a rectangular octohedron (fig. 9.) the angle formed
by the meeting of one plane of the upper pyramid, with the adja-
cent plane of the lower, being in one direction (P on P) 109° 18’
and in the other direction (P’ on P’) 78° 28’; and he says, ‘ Cet
octaédre se soudivise sur les arétes contigués.’
The Count de Bournon, for reasons given in his ‘ Catalogue,’
&c. (p. 357) considers the primitive crystal to be a right rhom-
boidal tetraedral prism, with rhombic bases, of about 78° 30’ and
101° 30’ (fig. 11.) which are about the measurements of P on P,
and P over the elongated edge of a crystal represented by fig. 10,
He adds that the sulphate of lead is among those substances in
which there is no trace of natural joints, no possibility of obtaining
a cleavage.*
* From the circumstance of the Count de Bournon having attributed to the angles of
what he conceives to be the primitive prism, measurements nearly approximating to those
of P on P, and of P on the opposed plane over the elongated edge of a crystal similar to fig.
260 Mr. WILLIAM PHILLIPS o7 the
The crystals of the sulphate of lead, as well those from Anglesea
as those from Cornwall, have so great a tendency to become prismatic
by the lengthening of what Hauy considers to be an octohedron,
and the Count de Bournon the primitive prism, that from among
several hundred crystals in my possession, I have been able to
select only one, having the appearance of an octohedron with
pointed apices, and that this elongation always takes place in the
same direction is manifest both from the uniform position of the
secondary planes in relation to those which are elongated, and by
the measurements afforded by numerous crystals; for although in
the latter respect there is not a perfect coincidence, the results are
sufficiently near to assure us of the fact.
The common base formed by the meeting of the two pyramids
of the octohedron described by Haity as the primitive crystal,
(fig. 9.) though rectangular, is not square. The meeting of two
adjacent planes on one pyramid, with their continguous planes on
the other, will therefore be at different angles, as is the case also
in respect of the primitive octohedron of the carbonate of lead.
The angle formed by the meeting of P’ with P’ is according to
Haiiy 78° 28’, and that of P with P 109° 18’. Six or seven crys-
tals submitted to the reflecting goniometer varied in P’ on P’
from 76° 4’ to 76° 20’. Nine crystals affording 16 measurements
of P with P varied from 101° 12’ to 101° 28’; and the same crys-
tals gave 17 measurements of P on the opposed plane of the same
10, which is common to this substance, it may be assumed that he considers such a crystal
to be a rhomboidal prism with diedral terminations. - It will appear that I agree with the
Count de Bournon in assuming the right rhomboidal prism with rhombic terminations as
the primitive form ; but differ from him in the manner in which that form lies (if it may
so be said) in a crystal represented by fig. 10. He conceives the planes P P, to be pri-
mitive: I am on the contrary induced to suppose the planes P’ P: to be primitive planes ;
we consequently differ in the angles of the prism. ;
Measurement and Cleavage of certain Primitive Crystals. 261
pyramid, varying from 78° 35’ to 78° 48’.. One elongated crystal
‘similar to fig. 10, gave P’ on the opposed plane over the summit
103° 40’. All these crystals reflected with uncommon brilliancy.
One of eight crystals, sufficiently bright to afford clear reflections on
each of the four elongated planes P P (fig. 10.) and more nearly
approaching to agreement than any of the others, gave on the two
obtuse angles 101° 12’ and 101° 15’, and on the two acute 78° 40’
and 78° 43’. Another among them gave one incidence of 78° 35’,
and another of 78° 48’ on the two acute angles.
1 am induced to be thus particular, not only on account of the
vast difference between the measurements given by Haiiy and
those obtained by means of the reflecting goniometer, but also be-
cause it is scarcely possible to find another in the whole range of
mineral substances, which seems to unite more decidedly the cha-
racters of perfect crystallization and brilliant surface. It seemed
therefore pre-eminently adapted to the use of the reflecting gonio-
meter. The result however proves that the sulphate of lead is one
among many minerals, on even the perfect reflections of whose na-
tural planes no reliance can be placed without numerous coinciding
results ; if indeed it would be possible to obtain them at all.
In the endeavour to cleave this substance paraliel with its natural
joints, I was at first greatly foiled by its extreme brittleness, which
without great care causes its fracture to assume the conchoidal
form. The directions for finding the joints given by Haiiy, are
quoted in his own words; if I comprehend them they are not
accurate, hut they are not expressed with his usual perspicuity.
As the elongated planes present the largest surfaces, it was an
inducement to attempt a cleavage parallel with them in the first
instance, on the presumption of their being planes of the primitive
octohedron ; but after destroying a large number of crystals, I was
VOL. Iv. 21 |
262 Mr. WiLLtam PHILLIPS on the
still unsuccessful. In the direction of the lesser planes (P’ P’) and
parallel with them, a cleavage is not only practicable, but may
readily be obtained by the assistance of a sharp penknife, when the
crystal is pressed on the fore finger beneath the thumb nail, which
is the most effectual mode I have been able to find. The crystals
are also divisible parallel with a section passing along the elongated
summit and down the centers of the planes P’ P’ of a crystal formed
like fig. 10. The search for natural joints in any other direction
was fruitless.
If therefore we divide an elongated crystal (fig. 10.) in the direc-
tion of the dotted lines 2b cde and bcd, being parallel sections in
the direction of its natural joints, we shall obtain a solid represented
by fig. 12, which occurs in nature, and greatly resembles some
crystals of the sulphate of barytes. If then this solid be cleaved
parallel with the planes P’ P’, we shall-obtain a nucleus similar in
form to the dotted lines within it, and of course to fig. 13; which,
though not in the same position, resembles in form, but not in
measurement, the primitive crystal of the sulphate of barytes
(fig. 2.) ; it is a right prism with rhombic terminations. Of these
solids obtained from amorphous specimens of the sulphate of lead,
I possess several, and am led to the conclusion that if we are to
depend on the cleavage of minerals for a knowledge of the forms
of their primitive crystals, this solid is that of the sulphate of lead.
In my collection there is an amorphous specimen from the Lead
Hills, exhibiting natural joints parallel with all the planes of a right
prism with rhombic terminations. It is covered on one of its
larger sides by long and nearly flat crystals with diedral terminations,
lying on the mass with the terminations parallel with the natural
joints observable in it; and there is a still more perfectly cha-
racterized specimen in the collection of Mrs. Lowry.
Measurement and Cleavage of certain Primitive Crystals. 263
On submitting to the reflecting goniometer several crystals cleaved
parallel with the planes P’ P’, they all afforded the result of 76° 18’,
coinciding therein with several fragments in the form of the primi-
tive crystal fig. 13, which also gave 103° 42’ as the value of the
obtuse angle. I am therefore induced to conclude that the primitive
crystal of the sulphate of lead is a right prism with rhombic ter-
minations, whose angles are 76° 18’ and 103° 42’.
Zhe
XIV. Supplementary Observations on Quartz Rock,
made in 1814.
By J. Mac Curtocu, M.D. F.L.S. President of the Geological Society,
Chemist to the Ordnance, Lecturer on Chemistry at the Royal
Military Academy, and Geologist to the Trigonometrical Survey.
[Read 17th February, 1815.]
Havine had an opportunity during the present summer of
adding some further remarks to the observations on quartz rock,
I have here arranged them as a supplement to the former papers, for
the purpose of extending the history and connections of this im-
portant member of the more ancient strata. As I had not the means
of examining a very wide extent of country, I have not been able
materially to enlarge its geographical boundaries, yet the Society will
see that it constitutes a very considerable part of the country I did
observe. It is found in most parts of the valley of the Tumel,
which extends from the head of Loch Rannoch to the junction of
the Tumel with the Garry. Throughout this whole extent it alter-
nates with schist, sometimes micaceous, now and then containing
felspar and thus resembling gneiss in composition, but oftener argil-
laceous, and very hard, from the large proportion of quartz which
it contains. As we approach the lower end of this valley the quartz
rock diminishes, while the schist increases, until the former at
length disappears. Beds of limestone are found alternating with it
throughout this course: it also contains porphyry, of which nume-
rous masses are to be seen on the sides of Loch Rannoch. These
Dr. Mac Cuttocn’s Supplementary Observations, Sc. 265
masses are sometimes truly porphyritic, containing crystals of felspar,
while at other times they consist of an uniform reddish compact
felspar, the usual basis of those porphyries which are found associated
with the primary rocks. There is much difficulty in determining
the true nature of these porphyritic masses. Occasionally they seem
to cut the strata, while in other places there can be no question that
they are parallel to them. Nevertheless I am still inclined to think
that even those which are occasionally seen conforming to the posi-
tion of the strata in which they lie, are, like the masses of trap
which have a direction parallel to the associated beds, only veins, of
which the direction is so far parallel to the position of the beds in
which they are found.
From Loch Rannoch the quartz rock is seen crossing the moun-
tains to Loch Ericht, accompanied in the same way with the
various schists, and finally terminating in different places round the
outskirts of Ben Vualach, where its junction with the granite of
this mountain is visible. It may then be traced along the southern
border of Loch Ericht, where it joins with a similar series of rocks
that will be found extending from Dalwhinnie along the course of
the Truim, and then along that of the Garry all the way to Blair.
A fact of some importance is visible at Loch Ericht which I will
mention here, although not particularly connected with the history
of quartz rock. About half way between the top and bottom of the
lake on the south side, a large slide of the mountain is to be seen;
the ruin is still so entire, of such magnitude, and so little encumbered
with recent accumulations of soil, that there is no difficulty in tracing
the fallen masses to the broken summits whence they were detached.
The quartz rock here, as in all the outskirts of this granitic country,
is traversed by granite veins. A few fallen stones have formed a
sort of cave capable of containing three or four persons, and known
266 Dr. Mac Curtocn’s Supplementary Observations
to the neighbouring shepherds, who, still mindful of their ancient
allegiance, show the spot where, among many others, the unfortunate
Prince was for a time concealed. The minuter fragments of quartz
rock and granite have here formed themselves into angular conglo-
merates, which are in some instances perfectly compact, the smaller
cavities having been filled up by siliceous matter, while the larger
fragments, touching only by small surfaces, have left considerable
Openings between them. Here then we have an example of a
breccia formed in times comparatively recent. The conglomeration
of the fragments is not the effect of the accidental presence of iron,
so commonly the cement of modern breccias, but is evidently the
result of a deposition of siliceous matter. ‘This could only have
been brought into solution by the rains, or by the operation of com-
mon water, since the stones are out of the reach of other causes,
and it serves to prove that the solution of silica in water, a circum-
stance which some have supposed limited to the ancient state of the
Globe, is a process still going on. I have indeed noticed in the
former remarks on quartz rock the same fact as proved by the ena-
melled and polished surface which its exposed parts so often assume.
We have no means from historical record of determining the anti-
quity of this s/ide, but as far as any conjectural evidence can be
adduced from the little accumulation of soil which has formed on
the horizontal surfaces, and the bare aspect of the faces, on which
scarcely a lichen has yet planted itself, it cannot be of very high
antiquity. The observation is further of importance as illustrating.
the origin of the brecciated jaspers, as well as that of the other
breccias formed of angular fragments.
From Loch Ericht the quartz rock branches away to the moun-
tains that skirt Ben Nevis and Glenco, as I noticed in the above
mentioned paper. I have already observed in that paper that it
on Quartz Rock. 267
constituted a portion of Schihallien and of the northern side of Glen
Lyon, terminating in the micaceous and chlorite schist of the ridge
of Ben Lawers. ‘Taking it up now from Blair we shall find it
occupying a large proportion of the whole group of hills which lies
between the Bruer and the Tilt, lying over the granite and stretching
away towards Glen Dee, and thus uniting with that tract of it which.
I also described last year as skirting the great granite mass of the
Grampians towards its eastern declivity. Returning again to Blair
it is found extending over the whole ridge of Ben Gloe, and here it
scarcely ever alternates with schist. From Ben Gloe it may be
traced over the Scarsough into Mar, forming at the same time Cairn
ree and a considerable extent of the hills which skirt Glen Fernat
and Strath Airdle to the eastward. From Mar it is then seen to
form a principal portion of the tract which bounds Glen Shee on
both sides, but further into the hills of Angus I have had no oppor-
tunity of following it. If the several spaces which I have described
here and in the former paper, be marked on the map, it will be seen
to occupy a very large portion of the country, and one which will
I doubt not be easily extended. I do not mean to lay it down asa
rule, (since the irregular position of this class of rocks is such that
they scarcely admit of any rule), but I think it will be found here
most abundant in the vicinity of the granite, while the micaceous
schist on the contrary lies at the greatest distance from it. A mine-
ralogical map of Scotland, a work as yet far distant, will probably
confirm the generality of this remark.
I have but little to add to the particular description of the rock
and of its several varieties given in the above named paper, but
there are a few circumstances worthy of record.
In Ben Gloe it is found incurvated and contorted in the manner
of micaceous schist, a proof that, like all the other schistose rocks
268 Dr. Mac Cutitocn’s Supplementary Observations
with which we are acquainted, it has occasionally been in a flexible
state. Some beds are also to be found there towards the east, on
that shoulder of Cairn Gower which hangs towards Loch Lochs,
containing rounded pebbles, such as I before described as occurring
in it at Jura. The beds in which this variety is found consist indeed
entirely of a loose aggregation of large and small rounded gravel,
This is only the second instance in which I have noticed a coarse
conglomerate mass as forming one of the varieties of quartz rock.
The pebbles are of considerable magnitude, and bear just such marks
of attrition as do those which have been rolled on a sea shore:
if they are not mechanically rounded pebbles I know not where
such can be found. I have little doubt that this variety will oftener
occur when these rocks shall have been more extensively examined ;
but I trust this fact is no longer necessary to prove that quartz rock
bears the marks of a mixed mechanical origin, and that it thus serves
to determine in some measure a corresponding set of circumstances
in which the schistose rocks associated with it were formed.
Near Blair it may be observed passing into a regular granite in a
very distinct manner. Many of the specimens found were trans-
ported stones, but in many other instances, which I have had occasion
to notice in a paper on Glen Tilt,* the transition from quartz rock
to granite is to be seen zm situ. I have there also noticed that, which
ought for the sake of uniformity to be repeated here, that the beds
of quartz rock which are in immediate contact with the granite often
pass into it by insensible degrees. It is well known that there is a
gradual transition from mica slate into gneiss, and that this rock again
by degrees equally evanescent passes into granite. I have shown
that quartz rock is here in contact with granite, and it is not there-
fore surprizing that it should, like the mica slate with which it
* Geo. Trans. Vol. III.
on Quartz Rock. 269
forms but one great deposit, undergo analogous changes when it
approximates to this rock. The transition is in fact more easy and
the boundary less definable, since many varieties of quartz rock,
formed of felspar and quartz in varying proportions with an occa-
sional mixture of mica, only require to assume that crystallized ap-
pearance which the vicinity of granite is so apt to produce on the
neighbouring rocks, to become undistinguishable from it. The quartz
rock in these specimens contains mica, disposed at first in a parallel
form, so that it might equally be ranked among the varieties of mi-
caceous schistus or of gneiss. By degrees the mica loses its parallel
disposition, and at length the whole assumes the aspect of granite.
This transition therefore adds one more to those passages into mica
slate, clay slate, and graywacke, which I formerly described as oc-
curring in quartz rock. Loose specimens are found both at Blair
and in Ben Gloe containing drusy cavities, of which the siliceous
crystals, though more minute than a pin’s head, are perfectly defined.
These crystals are evidently of posterior formation to the general
mass of the rock, and have resulted from the infiltration of a watery
solution of silica into previously formed cavities. ‘They prove no-
thing therefore relating to the chemical nature of this rock, of which,
mixed with its mechanical formation, there are every where to be
found abundant examples, some of which I have formerly enume-
rated.
In Glen Tilt I have taken out specimens from the beds exactly
similar to those long compressed and smooth cylindrical bodies which
are sometimes found in secondary sandstones. This shows another
distinct point of agreement between quartz rock and those sandstones.
In the same place is found a very interesting variety. It consists
of a regular and repeated alternation of quartz with common argil-
laceous schist ; the smoothest variety of clay slate. The quartz at
VOL. IV. 2M :
270 Dr. Mec CuLLocn’s Supplementary Observations
the same time is compact and crystalline, differing in no respect from
the most common specimens of this substance. ‘The alternations are
such and so frequent that a cross fracture of this rock may almost
be compared to the striped leaf of arundo colorata.
In another situation I observed specimens consisting of pure quartz,
without any such mixture of clay, but so fissile as to scale off in
leaves as thin as paper. DNs ca vas
Although garnets abound so much in mica slate, I have only met
with one instance in which they occur in quartz rock; this is at
the west end of Mar forest near the Dee. The garnets however are
very incomplete, although large in size; they occupy only the in-
tervals between the layers of the stone, and on splitting it are found
as if compressed between the surfaces.
Another remarkable variety of this rock also occurs in Glen Tilt.
It resembles precisely the schistose sandstones which accompany the
coal strata, and is found in distinct lamine from an eighth to a
quarter of an inch in thickness, detached from each other and sepa-
rated by thinner lamin of loose mica or clay. It offers another ex-
ample of the striking resemblance between quartz rock and the
secondary sandstones; an agreement much more remarkable than
that of the mica slate which generally accompanies it, with the slate
clay which is the associate of those sandstones. It would seem as if
the quartz rock from its greater simplicity of materials, a simplicity
less liable to chemical changes, had undergone fewer alterations
during the progress of time and of those actions by which its present
form was produced, than the more compound schist with which
it was originally associated. In those varieties of quartz rock which
are, like that last described, formed of distinct laminz, natural joints
occur resembling those of clay slate and producing on fracture,
ee eee
ad on Quartz Rock. 271
rhomboidal tables. In this respect it bears a considerable analogy
to the clay slates with which it is so often associated.
Among the varieties found in Ben Gloe I remarked some others
worthy of notice, considering the novelty of this subject and the
~ mecessity of describing every remarkable feature of a rock so long
overlooked or confounded with others. ‘The most singular of these
is of a beautiful pink colour, equal to that of the well known rose
quartz, with the semi-tr
refined sugar: it forms interesting specimens for collectors of mi-
arency and fine grain of the most highly .
nerals. I have mentioned it in describing Glen Tilt. Another is of
a dark brown colour, apparently from containing much carbonate of
iron, but when it is exposed to the weather the surface is bleached
to the depth of a quarter of an inch and becomes of a snowy
whiteness. A third is of an ochre yellow colour and loose texture,
and in hand specimens not to be distinguished from a common
secondary sandstone, while at the same time it contains distinct con-
cretions of crystallized carbonate of lime irregularly dispersed through
it. A variety equally resembling some of the secondary sandstones
which occur among the coal strata in the vicinity of Glasgow and
elsewhere, is found near Balahulish. It is distinguished by the fre-
quent alternation of black laminz, of which the cross fracture repre-
sents delicate lines, and it serves with othets already enumerated to
confirm the strong affinity of the recent sandstones with quartz rock,
the sandstone of former ages.
Among the various modifications of quartz rock which I have
observed in the different districts now described, a great many exhibit
the characters of the avanturine, the quartz avanturiné of Brongniart.
I have frequently noticed the transition which takes place between
quartz rock and mica slate, a transition so gradual and so perfect
that it is often impossible to assign the limits of the two. The quartz
Zm 2
272 Dr. Mac Currocn’s Supplementary Observations
is often hyaline, while the mica is disseminated through it in scales
of which the tendency, notwithstanding the crystalline state of the
quartz, is parallel either to the laminz or to the beds of the stone.
These specimens when polished exhibit the characters of the most
perfect avanturine, but their colours are only white or greyis
I have never yet met with the most esteemed, the yellow variety.
As the quartz rock approaches more nearly to mica slate, the cha-
racter of the specimens which resemble a :
avanturine nges, until
they resemble the variety of this Sreerierital mineral found at
Fkaterineberg. In many cases the scales of mica have a con-
siderably greater dimension in one direction than in another, from
which the stone acquires a fibrous aspect. This variety, of a
fine blue grey colour, occurs in Glen Fernat in large beds, and
when polished does not yield to some of the most beautiful foreign
specimens of avanturine. ‘There is yet one other modification of
this mineral, of which the splendour results merely from the vary-
ing position of the quartz grains which form it. The most crystal-
lized and pure specimens of quartz rock afford this variety, and
examples of it are to be found every where among the more com-
pact beds of that rock. We may therefore conclude that the avan-
turine, so much esteemed and:long so ill understood, is a variety of
quartz rock ; a circumstance likely to give this rock that importance
among collectors of specimens, which I have attempted to claim
for it among geologists.
on Quartz Rock. 2°73
Further Observations.
.
€ [Read 20th December, 1816. ]
the ey oe
" SiR,
For the sake of rendering somewhat more complete the history
of this substance, I shall here subjoin an account of a considerable
body of it which is to be seen in a very unexpected situation in
Sky. Although it will be found mentioned in the present volume,
in a supplementary paper on that island, it will not be irrelevant to
describe it in somewhat greater detail here.
A series of stratified rocks is found extending from the Kyle
rich, on the eastern side of this island, to Loch Eishort, on its
western side, and occupying a considerable space laterally, or con-
sisting of a frequent repetition of the substances which constitute
it. While the nature of these strata, which present alternations
of red sandstone with graywacké schist, and with indurated grey
and blue granular quartz, would incline us to rank them among
the secondary rocks, some doubt is thrown on that conclusion in
consequence of the peculiar relation they bear to the older rocks
which they follow, the gneiss, and the micaceous and chlorite schists.
But I must refer to the paper on Sky itself, for the history of these
strata, and limit myself to the description of the particular rock
which is the object of this note.
It forms a large mass of strata in an erect position, running
parallel with the red sandstone and the graywackeé schist, which, in
repeated alternations, lie on each side of it. These strata, always
274 Dr. Mac Cutiocu’s Supplementary Observations
highly elevated, are in some parts vertical, while in others they in-
cline, like the rocks by which they are accompanied, sometimes in
one direction and at others in the opposite one, from the perpendi-
cular, their bearing being north-easterly. Although the accompany-
ing strata extend from one shore of the island to the other, the —
quartz rock in question does not attend them throughout, the total
length which its leading mass occupies being limited to about five
miles, as nearly as that can be ascertained. Its south-western end
will be found in the hills behind the castle of Dunscaich, and its
north-eastern approaches the shore of Loch Eishort, nearly opposite
to a small island which forms the innermost harbour of that branch
of the sea. The collective breadth of the strata where they are
widest, appears to be about a mile and a half, while at each end it
is much less, but the nature of the ground does not permit their
whole extent or geographic shape to be accurately ascertained. In
a general view they form two irregular ranges of parallel elevations,
with shallow intermediate vallies, and as these summits maintain
scarcely any vegetation, while they are composed of white compact
quartz, their effect is very striking, even at a great distance ;- pre-
senting the appearance of a fall of recent and thin snow.
Besides this leading mass, many detached portions of strata of the
saine substance are to be seen in the neighbourhood, and they are
most accessible on the shore from Dunscaich to Ord. In these
places their alternation with the red sandstone and grey wacke schist
can be traced with great ease and satisfaction, while at the same
time their stratified disposition and their angles of inclination may
be examined in considerable detail. The small island of Dunscaich,
remarkable for the remains of a Danish strength, and a more pro-
bable residence of the traditional king of the Isle of Mist than the.
neighbouring promontory, affords particular facilities for examining
on Quariz Rock. 275
the nature and disposition of this rock. Here it is disposed in thin
beds, rarely exceeding a few inches in thickness, and is inclined
towards the east in an angle of about 26 degrees. These beds
are divided by natural joints, at angles with the plane of stratifi-
cation, and in consequence of this they break into prismatic rhom-
boidal or triangular fragments, which on the upper and long-ex-
posed surfaces are so numerous and minute that the whole presents
at first sight a set of sharp points and projections, among which
the stratified disposition is scarcely perceived until they are more
closely examined. ‘The same disposition into thin strata is every
where found throughout the larger masses, and if sometimes more
obscure, it can nevertheless be always discovered by an attentive
examination.
With respect to the composition of this rock it is almost always
found to be a compact splintery quartz, scarcely distinguishable in
small fragments from that mineral as it occupies veins. Occasion-
ally it becomes more or less granular, and now and then will be
found to contain grains of felspar, as it does in so many other
places. Its prevalent colour is white, but it sometimes assumes a
rusty colour at a small depth from the surface, and in some rare
instances may be observed of a pink and of a brown-reddish hue.
If there is any transition between this rock and those with which
it is associated, it must be sought among those beds which approach
to a granular structure, between which and the most compact
varieties of the red sandstone the difference is not extremely great.
I cannot say that I have positively ascertained such a transition,
nor am I aware that the nature of the ground is such as to admit
of an examination sufficiently connected and extensive to answer
this purpose. I shall however point out to geologists that part of
276 Dr. Mac Cuttocn’s Supplementary Observations, tc.
the shore which lies to the eastward of Ord, as particularly inter-
esting in this view; since, if it does not present examples of an
exact and satisfactory transition between the two rocks, it affords
very instructive views of the change which, under particular cir-
cumstances, occurs in the sandstones, from the distinctly granular
Be
and arenaceous to the compact and quartzose state.
XV. Description of a series of Specimens from the Plastic Clay near
Reading, Berks: with Observations on the Formation to which
those Beds belong.
By the Rey. WILLIAM BUCKLAND,
MEMBER OF THE GEOLOGICAL SOCIETY,
AND PROFESSOR OF MINERALOGY IN THE UNIVERSITY OF OXFORD.
[Read 6th January, 1816. |
CONTENTS.
Description of Beds of the Plastic Clay formation above the Chalk at Reading.
Extent of this formation of Plastic Clay.
Appearance of the same near London.
Sections at Woolwich, Lewisham, Blackheath, Plumsted, and New Cross.
Other localities of this formation in the London Basin.
Appearance of the same on the coast of Sussex.
Sections near Seaford and Newhaven.
Plastic Clay near Arundel.
Connection of beds of the Plastic Clay formation in England with the French
beds of the same era.
General character of the Plastic Clay formation in England.
History of the formation of the Marsh Lands immediately below London.
Havinc an opportunity to visit Reading in July, 1814, I col-
lected a series of specimens numbered as below, which I beg leave
to present to the Geological Society. The pits whence they were
obtained are at the Catsgrove Hill Brick kilns, distant about half
VoL. Iv. 2N
278 The Rev. W. BuckLanp on the Plastic Clay Formation.
a mile from the town of Reading, on the south-west, where the
works have been carried on for more than a century, and at this
time present the following section, beginning from the lowest
upwards.*
Section of Catsgrove Hill.
No. Thickness in Feet.
1. Chalk containing the usual extraneous fossils and
black flints . =) =m. =) Ue eee
2. Siliceous sand mixed with granular particles of green
earth, and containing both rolled and angular chalk-
flints, oysters, and many small and nearly cylindrical
teeth of fish from a line to an inch in length - - - 38
3. Quartzose sand of a yellowish colour with a few small
green particles, and containing no pebbles or organic
remains = = = =#= = == =.= = = = (=
4, Fullers’ earth - - - - - = = = = = + = =. 8
5. White sand used for bricks - - - - - - - - - 4
6. Lowest brick clay of a light grey colour mixed with fine
sand, and alittle iron-shot - - - =- - - - - 5§
7. Dark red clay, mottled with blue and occasionally. a little
iron-shot. It is used for tiles - - - - - - - 6
8. Bed called the White vein. A fine ash coloured sand
mixed with a small portion of clay, and in some parts
passing into loose white sand. It is used for bricks 5
9. Fine micaceous sand laminated and partially mixed with
clay, and occasionally iron-shot. It is used to make tiles 4
10. Light ash coloured clay, mixed with very fine sand of the _
same colour. It is used for bricks -- --- 7
* The measures in this and all the following sections were taken by the eye and do not ~
pretend to extreme accuracy.
The Rev. W. Bucktanp on the Plastic Clay Formation. 279
11. Dark red clay partially mottled and mixed with grey clay 4
12, Soft loam, composed in its upper region of fine yellow
micaceous sand, mixed with flakes of a delicate ash
coloured clay, which become more abundant in the
deeper portions of the stratum, and having its lower
regions much iron-shot, and occasionally charged with
ochreous concretions, and decomposing nodules of
iron pyrites. It is used to make soft bricks for arches 11
Total 57
13. Alluvium composed of clay, sand, and gravel, the gravel
chiefly consisting of chalk flints, both rolled and angu-
lar, with a few pebbles of quartz, and of brown com-
pact sandstone. This alluvium is covered by vegetable
mould: = - (<6 (ee Ue Sa ee
The oysters of No. 2 are remarkably perfect when first laid open,
and seem to have undergone no process of mineralization; they
soon fall to pieces by exposure to air and moisture. The chalk
flints contained in it are many of them in the state of small rounded
pebbles; in others the angles are unbroken. Both varieties are
covered with a crust of greenish earth of the same nature with the
green particles in the sand. The angular flints appear to have been
derived from the partial destruction of the bed of chalk immediately
subjacent, of which the upper surface in contact with the sand is
considerably decomposed to the depth of about a foot, and its
fissures and numerous small tubular cavities (the latter derived ap-
parently from the decay of organic substances,) are filled with gra-
nular particles of the green earth and siliceous sand of the incumbent
stratum.
2u 2
280 The Rev. W. Bucktann on the Plastic Clay Formation.
An appearance somewhat analogous is noted by M. M. Cuvier and
Brongniart (Essai sur la Geog. Min. des Environs de Paris, p. 17,)
in a coarse variety of the French plastic clay which immediately
covers the chalk at Meudon; where a breccia composed of frag-
ments of chalk imbedded in a kind of argillaceous paste has filled
the fissures and irregularities -which existed on the surface of the
subjacent chalk before the deposition of the plastic clay.
The same thing may be seen on a small scale in the chalk pit at
Woolwich, where there are fissures extending some feet downwards
into the body of the chalk, varying in breadth from an inch to more
than a foot, and sometimes spreading laterally so as to form con-
siderable cavities, which together with the fissures are filled with
sand that has been introduced from the incumbent stratum.
At Reading the chalk is quarried below the green sand contain-
ing oysters (No. 2) to the depth of about 25 feet, when the work-
ings are stopped by water at a point nearly on a line with the leve
of the river Kennet, below which there can be no discharge of
water from the chalk, through the medium of the neighbouring
springs. In this thickness of 25 feet of chalk, there is but one re-
gular and continuous course of flints, and in this they are dis-
posed in tabular masses, for the most part of about two inches in
thickness. (This bed is but a few feet above the water). In the
chalk that lies above this siliceous stratum, the flints are disposed
irregularly with their usual characters and eccentric forms, derived,
in many instances, from the organic remains which they envelope.
They are collected for the use of the porcelain manufactories. The
chalk itself is extracted largely from under the sands and clays, by
means of shafts and levels, to be burnt into lime. There are no
septaria or concretions in any of the strata above the chalk, nor
the smallest traces of animal or vegetable remains, excepting in the
The Rev. W. BucKLAND on the Plastic Clay Formation. 281
green sand, (No. 2.) The same barrenness of organic remains is
noticed in the purest beds of the French plastic clay, and by Mr.
Webster (Geol. Trans. vol. 2, p. 200), in the plastic clay of the
Isle of Wight and Corfe Castle.
The section given by Dr. Brewer, in the Phil. Trans. for 1700,
differs as little as might be expected from that which is now ex-
posed at Reading. Beginning from the bottom, he gives the fol-
lowing strata :
No. Feet.
1. Chalk rock - - . = . - anges
2. Green sand containing oyster shells - - - 2
3. A bluish sort of clay, very hard, brittle, and rugged
(called pinney clay) ; it is of no use - - 3
4, Fullers’ earth 7 s ty = < ay ary (DE
5. Clear fine white sand ai 2 “ e ” eawle
6. Stiff red clay used for tiles, the depth of which, he says,
could not conveniently be taken from the heighth of
the hill, at the top of which, he adds (immediately
under 2 feet of common earth) the red clay appears,
and is used for tiles.
The thickness of the beds which Dr. Brewer did not measure
was probably made up of those from No. 7 to No. 12 inclusive,
in the section I have given, in which also the beds below No. 6
correspond very nearly with his account, which I had not seen till
my own was finished as it now stands.
In a hill called David’s Hill, west of the town of Reading, on the
opposite side of the Kennet to that of the Catsgrove brick kilns,
and about one quarter of a mile distant from them, are other large
quarries of brick earth, in which many of the subdivisions which
have been noted at Catsgrove are not to be recognised, and the
282 The Rev. W. BuckLanp on the Plastic Clay Formation.
entire thickness of some of the pits is made up of the same sands
and clays as on the opposite side, but more uniformly disseminated
through the whole mass, forming a kind of loam more like No, 12
than any of the other beds that have been there described; ochre-
ous concretions and pyritical nodules abound in it as in No. 12.
The total thickness of this deposition at David’s Hill above the chalk
is about 40 fect. Water occurs in the subjacent chalk, as soon as
they sink 30 feet into it. It is separated from the incumbent brick
earth by the bed of green sand, with the same oysters as at Cats-
grove.
The whole of these beds above the chalk at Reading (those at
Catsgrove as well as at David’s Hill) appear to be subordinate parts
of one formation, the next in order of succession above the chalk,
older than the London clay and calcaire grossier of Paris, and
contemporaneous with the lowest strata of the plastic clay forma-
tion nearest the chalk, the general history of which we propose
more fully to consider.
On the north side of the town of Reading these strata do not
occur, being cut off by the great valley through which the Thames
passes, and which has been excavated to a considerable depth in
the subjacent chalk. But they occupy much of the ground be-
tween Reading and Newbury, and are seen at Hermitage, on the
N.E. of Newbury towards Hamstead Norris, whence a range of low
hills composed of them stretches eastwards towards Reading, and
westward to Boxford, Wickham, and the neighbourhood of Hunger-
ford, interrupted by vallies, which are often cut down into the sub-
jacent chalk. |
The breadth of this deposition on the north and south of New-
bury, is from Beedon Hill six miles north on the road to
Market Usley, to Whitway near Highclere four miles south of
The Rev. W. BucKLAND on the Plastic Clay Formation, 283
Newbury on the road to Whitchurch. On the west of this line,
drawn through Newbury north and south, the breadth of the beds
on the chalk is gradually contracted till they entirely cease near
Hungerford (See Mr. Webster’s map, Geol. Trans. vol. 2, pl. | 0).
On the east side of the said line they occupy the vale of the Kennet
till it falls into that of the Thames, near Reading; whence they
extend eastward, widening as they advance through Surry and
Middlesex, into Kent, Essex, Suffolk, and Norfolk.
In many parts of this great valley or trough of chalk we recog-
nize our Reading beds in their proper place, as the inferior strata
of the plastic clay formation; and though withthe exception of
the lowest bed they do not agree in minute detail with those of
the Reading section, as to thickness, or exact order of superposi-
tion, nor is the presence of shells or pebbles constant in the beds
of clay or sand, yet an attentive examination of the general points
of resemblance in the substance of the clays, sands, and pebbles,
forming these irregular alternations above the chalk, added to the
identity of their organic remains when any occur, leaves no doubt
as to their being members of one great series, of nearly contempo-
raneous depositions, intermediate between the chalk and London
clay, and which it may be convenient to associate in a natural
family, as members of that formation of which it is one leading
feature to contain those peculiar varieties of clay which the French
naturalists have characterized by the appellation of plastic clay.
‘As there can be little doubt of the origin of the French beds being
contemporaneous with those in England we are now considering,
it will assist us in connecting our strata with those of the Conti-
nent, to designate them by the appellation appropriated to them in
France.
Near London these beds occur with well defined characters ; at
284 The Rev. W. BuckLAnD on the Plastic Clay Formation.
Blackheath, Lewisham, Charlton, Woolwich, and on the east of
Plumsted. In all these places the thin bed next above the chalk,
which at Reading contains fishes teeth and oysters, is seen com-
posed of a similar substance of ioose green sand mixed with chalk
flints, both rolled and angular, and generally coated with a dark
green crust; but here they contain no organic remains, and seldom
exceed two feet in thickness. Above this thin bed is a thick stra-
tum of fine grained ash coloured sand, destitute of shells or pebbles,
and varying in thickness generally from 30 to 40 feet. This stra-
tum is seen to the greatest advantage in the Woolwich sand pits,
where is an enormous artificial section, presenting the following |
order of succession : *
Section of the Woolwich Pits, ascending from the lowest Strata.
(See coloured Section, Pl. 13, No. 1).
1. Chalk with beds and nodules of black finn - - —
2. Green sand of the Reading oyster bed, containing green
coated chalk flints but no organic remains - + ok
3. Light ash coloured sand without shells or pebbles - - 35
4, Greenish sand with flint pebbles 2 = Z Lg
5. Greenish sand without shells or pebbles - - -
6. Iron-shot coarse sand, without shells or pebbles, and con-
taining ochreous concretions disposed in concentric la-
mine - ~ - - = - - - 9
* Although a Section of these pits is already before the Society, it seemed necessary to
insert that I am now giving, as it differs from Mr. Webster’s (Geol. Trans. vol. 2, p. 195.)
in a few minute particulars, and was the result of a careful examination by the Rev. Wm.
Conybeare and myself, in April, 1815. I have also the sanction of Mr. Conybeare’s
authority, and am indebted to his observations, confirmed subsequently by my own, for
the Notices, Map, and Sections, which I have given of the neighbourhood of Blackheath.
The Rev. W. BuckLanp on the Plastic Clay Formation. 285
7. Blue and brown clay—striped and full of shells, chiefly
cerithia and cytheree = - - - - - - «9
8. Clay striped with brown and red, and containing a few
shells of the above species = = - - - —12 6
9. Rolled flints mixed with a little sand, occasionally con-
taining shells like those near Bromley; e.g. ostrea,
cerithium and cytherea. (These shells occur dissemi-
nated in irregular patches) —- - - - - 12
10. Alluvium - - - - - ~ - —
Total thickness 81
No. 1 and 2 are not laid open in the great sand pits, but are seen
in a chalk pit adjoining to the eastern extremity of the sand pit.
The following section at Loam Pit Hill, near Lewisham, about three
miles south-west of Woolwich, presents analogies that identify many
strata in the two sections, as from the chalk upwards to No. 8; in
each inclusively the principal difference consists in the presence of
fewer or more pebbles, in beds of sand evidently contemporaneous.
Section of three Pits on Loam Pit Hill, near Lewisham.
(See coloured Section, Pl. 13, No. 2*).
LOWER PIT.
No. Feet.
1. Chalk with beds and nodules of flint - - - —
2. Green sand identical with the Reading oyster bed, and in
every respect resembling No. 2 at Woolwich - nit agl
* These beds cannot all be observed at one section, but may be traced along the sloping
surface of the hill, at three successive apertures near each other, in which the upper stra-
tum of each lower pit is dug into, and forms the floor of the one next above it.
In the section No. 2, the intermediate spaces are unnaturally contracted, and expressed
by two narrow caps of alluvium.
VOL. Iv. 20
286 The Rev. W. Buckianp on the Plastic Clay Formation.
No. Feet.
3. Ash coloured sand, slightly micaceous, without pebbles or
shells - - - - “ i Z =) Vea
This bed, though below the general floor of the middle pit,
is sunk into from it by deep shafts.
‘MIDDLE PIT?' 3M, ai
4. Coarse green sand, containing pebbles - - - §&
5. Thick bed of ferruginous sand, containing flint pebbles 12 —
6. Loam and sand, in its upper part-cream coloured, and
containing nodules of friable marl, in its lower part
sandy and iron-shot = - - - - - 4
7. Three thin beds of clay, of which the upper and lower
contain cytherex, and the middle oysters + - 8
UPPER PIT.
8. Brownish clay containing cytherez - - -—
This is the lowest bed sunk into in the upper pit, and is not
there penetrated to a depth exceeding one foot. ‘The in-
terval between this and No. 7, which occupies the summit
of the middle pit is not exactly ascertained, but cannot be
considerable ; probably - - = - - - 6
9. Lead coloured clay, containing impressions of leaves - 2
10. Yellow sand - . tit hits 2 a ~ ae
11. Striped loam and plastic clay, containing a few pyritical
casts of shells, and some thin seams of coaly matter - 10
The Rev. W. Buckianp on the Plastic Clay Formation. 287
No. Feet.
12. Striped sand, yellow, fine, and iron-shot - - - 10
13, Alluvium * - - , x “ “ Sigg atte
Total 91
At a point still higher on this hill than No, 12, is a thick bed of
dark blue clay, without shells, which is used to make tiles and bricks,
and which appears to continue upwards from this brick kiln to the
summit of the hill, forming a thick cap over the sands and clays
mentioned in the section, and is probably an outlying hummock of
the London clay, separated only by a small valley from the exten-
sive mass of that stratum which is found two miles south-west in the
Sydenham hills , and being placed between and connecting them
with the London clay of Shooter’s hill. +
* In this alluvium four large and entire tusks of elephants were discovered a few years
ago, in a garden opposite the chalk pit, at the base of Loam Pit Hill, and on the north
side of the turnpike road; they soon perished by exposure to the air, but were for some
time in the possession of Mr. Lee, the owner of the extensive brick works on Loam Pit
Hill, to whom I am indebted for this information.
+ Mr. Webster mentions (Geol. Trans. v. 2, p.235) that rounded flints are found in the sand
strata, at the bottom of the blue or London clay, in several parts of the London basin. And
again (p. 185), that the abundant supply of water which is constantly found in boring
through the same clay, indicates an extensive deposition of three beds of sand. The
sandy strata containing pebbles, and the watery sand thus alluded to appear to be the
continuation of the upper strata of the plastic clay formation, and connected with those °
of Loam Pit Hill.
In the shaft at the northern extremity of the tunnel under the Thames, near Rotherhithe,
these same beds were found, covered by more than 30 feet of London clay, although
from their rapid rise under the bed of the Thames towards the south, the shaft on the
south side (of which Mr. Webster has given a section, p. 197) exhibits only nine feet
of this clay incumbent on the watery gravel and subjacent beds of the plastic clay for-
mation. ‘
A curious section is preserved in Sir C. Wren’s Parentalia (p. 285), obtained in pre-
paring the foundations of the present cathedral church of St. Paul, in London.
202
288 The Rev. W. Buckianp on the Plastic Clay Formation.
‘A similar section to that at Woolwich and Loam Pit Hill may be
traced round the sloping terrace that bounds the north-west and south
sides of the plain of Blackheath.
On the east side the beds composing this plain appear to be covered
by the clay of Shooter’s Hill, an outlying summit of the London
clay, like the hills of Sydenham and Highgate, and which probably
at one time were all united in a continuous stratum covering the
entire series of the plastic clay formation, which is now exposed
between the intervals of its remaining fragments. (See map and
section, Pl. 13.)
The plain of Blackheath (being a portion of the strata thus laid
open,) is covered at the surface with a bed of rounded pebbles,
sometimes 20 feet in thickness, which appear to be alluvial, but are
of nearly the same substance with the gravel of the neighbouring
strata, from which it is therefore matter of great difficulty to distin-
guish them. Beneath these pebbles is a bed of sand identical with
The Surveyor observed that the foundations of the old church stood upon a layer of
very close hard pot earth, which he therefore judged firm enough to support the new
building ; and on digging wells in several places he found this pot earth to be about six feet
thick and more, on the north side of the church yard, but thinner and thinner towards
the south, till it was scarce four feet upon the declivity of the hill. Below this he found
nothing but dry sand, mixed sometimes unequally, but Joose, so that it would run through
the fingers. He went on till he came to water and sand mixed with perriwincles and other
sea shells; these were about the level of low water mark. He continuc:! boring till he
came to natural hard clay.
The upper stratum of pot earth had been used at a Roman pottery, near the N.E. angle
of the present church, where they found urns, sacrificing vessels, and other pottery in
great abundance, and were interrupted in digging the foundation of the N.E. angle of
the church, by the quarry from which the pot earth had been extractcd: the subjacent
sand and gravel beds being considered too loose to support the weight of the intended
building, it was thought necessary to secure this part of the foundation by erecting it
upon an arch, The outer or N.E. pier of this arch stands in the old clay pit, in a shaft
sunk to receive it more than 40 feet below the stratum of pot earth that had been removed,
and descending through the beds of sand and gravel above mentioned, to the subjacent
stratum of hard clay.
The Rev. W. BuckLAnp on the Plastic Clay Formation. 289
No. 12 at Loam Pit Hill. This sand lies on a bed of plastic clay
which supports the water of the well in Mr. Conybeare’s garden,
and of all the wells on the plain of Blackheath at no great depth ;
it possesses the same peculiar dark red colour, with the plastic clay
of Reading, Corfe Castle, and Paris, and has been used for pottery.*
Beneath this clay the Woolwich shell beds and subjacent thick ash
coloured sand are to be seen in several parts of the sloping terrace
that surrounds the Blackheath plain. Under these on the north and
west sides appears the chalk, separated from the ash coloured sand
by the same thin pebble bed as at Reading. This pebble bed not
attaining the thickness of one foot may be seen at the junction dis-
played by the descent to some ancient subterraneous quarries in
chalk, called the caves, on the north side of the road ascending to
Blackheath from Deptford ; it may be seen also on the south side of
the same road in some chalk pits on the slope of the hill: in both
places it is covered by the thick ash coloured sand.
In the lane that leads down from the village of Charlton to the
Thames, is a good section shewing the Woolwich shell beds incum-
bent on the ash coloured sand which appears there in great thickness.
The church of Charlton is on the edge of the continuation of the
* It is probable that the plastic clay contains at Blackheath as at Corfe Castle, Alum
Bay and Loam Pit Hill, the remains of vegetable matter in a state approaching to coal ;
and that this circumstance has given origin to the erroneous opinion so prevalent, that
there is good coal at Blackheath if Government would allow it to be worked.
The very high improbability of finding good coal above the chalk is acknowledged by
all who have even the smallest acquaintance with the geological relations of the English
coal mines. ‘The presence of black vegetable matter in a state approaching charcoal
in almost all our secondary argillaceous strata, has caused endless vain attempts to search
for useful coal in formations where the discovery of that substance would be contrary to
all experience in this country. No good coal has I believe been yet found in England
in any stratum more recent than the new red sandstone, or red rock marl. That of the
Cleveland Moors in Yorkshire, being above lias and in the oolite formation, is of so bad
a quality as scarcely to form an exception to this position.
290 The Rev. W. Buckiawp om the Plastic Clay Formation.
plain of Blackheath, which extends thence eastward to Plumsted
Common and Boston Heath. (See map, Pl. 13.)
On the inner edge of this platform at the Plumsted Common
brick kilns, which are at the base of the north-east extremity of
Shooter’s Hill, a large section exposes the London clay, abounding
in selenites and septaria. ‘This clay is dug for brick tiles and coarse
pottery. In the same field with the clay pits and on the north side
of them a shaft is sunk 120 feet to the surface of the subjacent chalk,
which has been extracted to the further depth of 24 feet, being the
object for which the shaft is made. ‘The upper portion of this shaft
is in alluvial gravel, between which and the chalk occur the Wool-
wich sands. Another shaft was begun in the same fields still nearer
to the base of Shooter’s Hill, but abandoned from the quantity of
water that came in when they were at a depth of which the plastic
clay should be found if continued to this point from Woolwich in
the same relative position which it there occupies. The same thing
happened in an adjoining field, where the shaft for chalk was stopped
by the water at the depth of 36 feet.
In a ravine at the east end of Plumsted Common that falls towards the
Thames, the plastic clay that upholds the water of these wells and shafts,
is laid open on each side of the hollow way, and throws out a line ©
of springs at its junction with an incumbent stratum that is identical
with the bed covering the plastic clay at Blackheath and Woolwich.
On the east of this ravine in a deeper hollow called the King’s Highway
we recognise the sand and gravel beds below this plastic clay corres-
ponding with Nos. 4, 5,6, of the Woolwich Pit, and 4, 5, 6, of the
Loam Pit Hill section ; beneath these is the ash coloured sand No. 3
of Woolwich. The King’s Highway descends into a still deeper
valley (through which runs the road leading from Plumsted to
Wickham) ; this valley is cut to a considerable depth in the chalk.
Sa =
The Rev. W. BucKLANp on the Plastic Clay Formation. 291
The north-east side of it is steep, and has at its base a large chalk pit,
the top of which displays the Reading oyster bed one foot thick
between the chalk and incumbent ash coloured Woolwich sand.
The plain at the summit of this bank is Boston Heath, where a
well has recently been sunk about 200 feet ; through gravel 65 feet,
sandy beds 65, chalk 70. The water stands five feet deep in the
chalk. I could get no accurate detail of the sinkings, but learnt that
in descending they came to water far above the chalk though not in
quantity sufficient to supply the well. The upper gravel in this
well, and in the shafts at Plumsted, appears to be alluvial, though
like that at Blackheath composed almost wholly of pebbles of rolled
chalk flints, such as the neighbouring strata of the plastic clay for-
mation contain abundantly, and from which they were probably
derived.
The thickness of the alluvium in this district is exceedingly irre-
gular, swelling suddenly, and as suddenly disappearing. It covers
however nearly the whole surface of the under table land extending
from Blackheath to Plumsted Common and Boston Heath, and is
found also on the upper table of the summit of Shooter’s Hill, as well
as on many parts of the slope of its sides. The slopes that fall from
the under table to the valley of the Thames are so frequently and so
completely covered by this alluvium that except in places where
| they are laid open by artificial sections, it is difficult to discover the
existence of any strata of the plastic clay formation. A striking
example of this fe t may be seen in the Park at Greenwich, where
nearly all traces of the subjacent beds are concealed by a mass of
alluvium along the steep slope where we might expect to see them
exposed, and where there can be no doubt of their existence from
the strength and regularity in which they appear at Charlton and
Woolwich on the east, and near Deptford on the west of Greenwich
Park along the continuation of the same escarpment,
992 The Rev. W. BucKLanp on the Plastic Clay Formation.
In the banks of the Croydon canal at New Cross near Deptford is
another section that confirms the place that has been assigned to the
Woolwich beds below the London clay, and connected with the
plastic. ‘The section does not penetrate so deep as the thick ash
coloured sand of Woolwich ; but in the canal bank above the bridge
we have the following beds laid open, though not sufficiently to
ascertain their exact thickness, it does not however vary much from
that of the upper beds in the Woolwich pits.
Section at tbe Canal in New Cross, beginning from the lowest bed.
No. ‘
1. Plastic clay abundantly charged with the same shells as in the
Woolwich pits.
2. Bed of small pebbles chiefly of rolled chalk flints.
3. Sandy loam and plastic clay.
4. Blue clay full of small selenites, probably the Lotidott clay. »
The blue clay, No. 4, probably owes its selenites to the decom-
position of its shells and iron pyrites ; at present no shells are visible
near the surface. Its juxta position to the London clay of the
Sydenham Hills, of which it seems to be the continuation at their
north-east extremity, goes far to identify it with that formation. The
plastic clay, No. 3, is used for bricks and coarse pottery in a field
adjoining this canal called Counter Hill, close to the New Cross on
the east; and the Woolwich shell beds may be seen again at a lock
of the canal about a mile above New Cross towards Croydon, in the
plain that lies under the east side of the Sydenham Hills. At this
lock Mr. Warburton pointed out to me the following shells. Ancilla
buccinoides, cerithium denticulatum, cyclas. deperdita, a small bucci-
num, and a small nerite.
Oe ——
The Rev. W. BuckLanp on the Plastic Clay Formation. 293.
It is mentioned by Woodward that the Woolwich shells are found
at Camberwell and Beckenham, on the north-west and south-east
sides of the Sydenham Hills. I have other authority for their occur-
rence at the following places on the south side of the Thames,
Camberwell, Redriffe Tunnel, New Cross, Lewisham, Blackheath,
Woolwich, Plumsted, Beckenham, Bromley, Chislehurst, Bexley,
Cockleshell Bank, two miles south of South Fleet, Windmill Hill near
Gravesend, and Higham on the Thames and Medway canal. They are
found also at Rungewell Hill near Epsom, and at Headley between
Epsom and Dorking.
These localities seem sufficient to warrant us in concluding that
the formation of plastic clay extends over a large space in the south
portion of the valley of the Thames from Reading to Gravesend.*
Woodward mentions oysters as being found on the north side of
the Thames in a stratum of sand that covers the chalk near Hertford;
this probably is one of the oyster beds of the plastic clay formation.
I remember that in 1806, fire bricks were burnt from some beds
of fine sand and clay in the Park at Bulstrode, by the late Duke of
Portland, and that moulds for refining sugar were (and are still)
made within a mile of it, at some clay pits on the north side of the
* In Chislehurst, at the north-west angle of the park at Camden Place, the section of a
chalk pit displays a great thickness of the ash coloured Wootwich sand, separated from
the chalk by the thin pebble bed as at Reading,
The thick Woolwich sand (No. 3,) occurs also at Bexley, where (as is the case in
many of the woods about Dartford) shafts 40 or 50 feet in depth have been sunk through
it at an early period for the purpose of extracting the subjacent chalk, as is now done at
Reading, and Plumsted brick kiln. Mr. Hasted, in his History of Kent, conjectures that
many of these quarries were excavated by the Saxons, as places of retreat in times of
danger. He states that some of them are 20 fathoms in depth, and that they are to be
found also near Feversham, and at Fritwood on the south of Murston Passage near
Milton. The explanation that is suggested by the geological position of all these places
appears to be much more satisfactory.
VOL. IV. 2p
294 The Rev. W. BucKLAND on the Plastic Clay Formation.
London road about two miles east of Beaconsfield. ‘These with
other extensive beds of the same era which occur between Bulstrode
and Windsor, are in almost immediate contact above the chalk, and
appear to belong to the formation of plastic clay. The Windsor fire
bricks and soft sandy bricks for arches, are probably also made from
beds of this same formation. Mr. Warburton has been told that at
Clewer near Windsor, the Thames cuts through a bed of shells which
he suspects to be the same as are found at Woolwich.
We will now leave the beds of the plastic clay formation in the
London basin, to trace them in the same relative position on the
coast of Sussex.
A similar deposition of sand to that of Reading containing a breccia
of chalk flints as its lowest stratum, (about three feet thick) was
noticed by the Honourable H. G. Bennet and myself in July, 1814,
between Newhaven and Beachy Head, in the cliff at Chimting
Castle half a mile on the east side of Seaford. The sand here is
fawn coloured passing into olive with flakes of mica almost a line in
diameter, and occasionally contains irregular veins and masses of
tubular concretions of iron-stone. Its greatest thickness is under
50 feet. Mr. Warburton informs me that he has seen similar con-
cretions in the same stratum of sand at Sudbury in Suffolk, in im-
mediate contact above the chalk. Under this sand at Chimting the
breccia of the lowest bed forms an ochreous pudding stone composed
of sand and chalk flints, (the latter both rolled and angular) the
whole being strongly united by a ferruginous cement, and the flints
covered externally with a green coating like those in the oyster bed
at Reading. Specimens of this breccia have been presented to the
Society by the Hon. H. G. Bennet. At Chimting Castle there is
but a small insulated portion of these strata immediately incumbent
The Rev. W. Buckianp on the Plastic Clay Formation. 295
on the chalk. This chalk rises suddenly to a lofty cliff on the east
side of the flat ground that lies between Newhaven and Seaford,
dividing the beds of the plastic clay formation at Newhaven from
their outlying fragment at Chimting, with which they probably were
connected before the excavation of the valley of the Ouse.
The upper surface of the chalk at Chimting, as seen in the cliffs,
dips at an angle of about 20° to the west. ‘The dip of the incumbent
beds of breccia and sand is conformable with it. These last beds
are soon lost in ascending the hill eastward from the Castle; first the
sand ceases, and afterwards the breccia having formed a thin cap on
the chalk for a short distance disappears a -little below the Signal
House about one mile east of Seaford. Hence the chalk extends
forming a cliff to Cuckmere Haven, where on the heights composed
of it on the west of the Cuckmere river, we sought in vain for the
stratified sand and breccia, finding nothing but an alluvial cap of
sand and gravel; and as far as the eye could judge, looking eastward
from this point, there was no appearance of superior beds on any
summits of the chalk which forms the entire substance of those
magnificent cliffs that extend from Cuckmere Haven to Beachy
Head.
At Newhaven, in the lowest part of the Castle Hill close to the
mouth of the Ouse on the west: side, we again found the breccia
that has been described at Chimting Castle, nearly of the same thick-
ness and in the same state and relative position between the upper
surface of the chalk and the incumbent beds of sand; it differs from
it only in being less firmly cemented, and appears equally identical
with the oyster bed at Reading. The greater number of its flints
are not much rolled. ,
The state of the tide, and their elevated position, prevented us
from examining the hollows on the surface of the chalk in which
Z2pP2
296 The Rev. W. Buckianp on the Plastic Clay Formation.
Mr. Webster discovered the pure alumine; we found however a
large loose block containing this substance which filled cavities and
veins in a mass of singular structure, composed of irregularly con-
centric thin layers of gypsum alternating with still thinner lamine
of ochreous iron ore. There were also small crystals of selenite in
the same cavities with the alumine. The whole mass had strong
marks of stalactitic origin, and was probably introduced into one of
the cavities on the surface of the chalk by infiltration from the in-
cumbent beds of marl, which abound in shells and iron pyrites, and
contain all the elements from which the alumine, iron, and gypsum
might be derived.
In this cliff of the Castle Hill at Newhaven the following section
is presented, shewing beds of the plastic clay formation above the
chalk.
Section of the Castle Hill at Newhaven, commencing from the
lowest bed.
No. Feet
1, Chalk, containing alumine in hollows on its surface - - 50
2. Breccia of green sand and chalk flints, the latter covered
with a ferruginous crust - - - - - - - = - J
3. Sand, varying from yellow to green and ash colour - - 20
4, Series of clay beds containing coaly matter, selenites and
fibrous gypsum, also leaves of plants, and sulphur-
coloured clay - - - - - - - - = = = - 20
5. Foliated blue clay containing cerithia, and cyclades, and a
few oysters - - - - - = = = = - = = - 10
In this clay is a seam of iron pyrites about an inch thick
with pyritical casts of cyclades and cerithia.
The Rev. W. BuckLaAnp on the Plastic Clay Formation. 297
No. Feet
6. Consolidated argillaceous rock full of oysters, with a few
cyclades and cerithia - - - - - - - - = = 5§
7. Alluvium full of broken chalk flints mixt with sand - - 10
116
On comparing this section with those we have given in the London
Basin we shall find a correspondence very striking. (See coloured
sections, Pl. 13, No.1 & 2.) On the same chalk No. 1. is the Reading
Oyster bed, No. 2. which though inconsiderable in thickness seems
constantly to form the next stratum above the chalk, though organic
remains have been noticed in it only at Reading. No. 3, at New-
haven, is the ash coloured sand of Woolwich in diminished thick-
ness. Nos. 4, 5, and 6, appear to be an enlarged condition of the
plastic clay bed No. 7 and 8 of Woolwich, and from 7 to 11 in-
clusive at Loam Pit Hill.
We again observed localities of the red variety of plastic clay in
a small valley at the village of Binstead, three miles west of Arundel,
and again on the declivity of the hill by which the Binstead and
Chichester road descends into Arundel.
These insulated portions of strata of the plastic clay formation
that have been noticed at Seaford and Newhaven, and other places
at the south base of the chalk hills of the South Downs of Sussex,
appear to be outlying fragments at the eastern extremity of the great
series of depositions above the chalk in the south of England, which
Mr. Webster describes as extending from near Dorchester by the
Trough of Pool and the New Forest to Portsmouth, Chichester, and
the flat coast on the south-east of Arundel. (See Mr. Webster’s
Map, vol. ii. Geo. Trans. Pl. 10.*) Here they enter the English
Channel, and just touching the coast with their outlying fragments
998 ‘The Rev. W. BuckLAnp ox the Plastic Clay Formation,
at Newhaven and Chimting Castle, appear again on the opposite
shores of France in the same relative position.
I am indebted to the kindness of M. Brongniart for the following
section near Dieppe, which forms a valuable link connecting the
formations above the chalk in France with those of the same era in
the south of England. He has observed the following strata in the
perpendicular cliff under the light-house of St. Margaret, on the west
of Dieppe, counting upwards from the lowest stratum :
1. Chalk.
2, Sand and sandstone in thick beds containing concretions of the
same substance.
8. Strata of plastic clay, impure and containing lignite much
charged with iron pyrites, also oysters and cerithia, both in beds and
irregularly disseminated.
4, Alluvium.
These strata M. Brongniart considers as identical with beds of the
plastic clay formation in many other parts of France, particularly at
Marly, and in the Soissonnois, where the same organic remains oc-
cupy strata similarly disposed and identical with those near Dieppe.
I shall add a few more circumstances of resemblance in the French
and English formations of plastic clay.
It is noted by M. M. Cuvier and Brongniart, that in the basin of
Paris the sand between the chalk and plastic clay, though very pure,
is often coloured red or bluish grey. In the latter state it occurs at
Woolwich, Lewisham, and Newhaven. We have already (p. 280.)
stated the analogy which the Reading oyster bed bears to the brec-
ciated bed next above the chalk at Meudon. Of the plastic clay it
is also stated by the same authority that it often consists of two beds
separated from each other by a stratum of sand. The lowest of these
two being properly the pure plastic clay, while the upper is coarse,
hi
5 4
The Rev. W. BuckLanD on the Plastic Clay Formation. 299
sandy, and blackish. The sand dividing them is also said to vary
in colour like the plastic clay itself, from white, grey, and yellow, to
grey mixed with red and pure red. The English beds of plastic clay
and the sands attending them at Reading, Corfe Castle, and Alum
Bay, exhibit analogous variations in colour and consistency ; indeed
at the latter place they run through almost every possible combina-
tion in the scale of colours. Between the upper plastic clay and
calcaire grossier of Paris, there is also stated to be sometimes found
a bed of sand of irregular thickness, which they are doubtful whe-
ther to consider as belonging to the formation of plastic clay or cal-
caire grossier, but are rather inclined to attribute it to the former.
It contains organic remains in very few places. Is it not improbable
that this bed is contemporaneous with some of the upper strata of
the plastic clay formation which we find at Loam Pit Hill, at Black-
heath, and in the Isle of Wight, at which last place the beds belong-
ing to this series are accumulated to a thickness far greater than has
been yet noticed in any other spot, amounting at Alum Bay, ac-
cording to Mr. Webster, to 1131 feet, interposed between the chalk
and London clay.
Viewing it on the great scale then we may consider this formation,
which has been characterized by the title of plastic clay, as com-
posed of an indefinite number of sand, clay, and pebble beds, irregu-
larly alternating. Of these, the sand forms in England, the most
extensive deposition, in which the clay and pebbles are interposed
subordinately and at irregular intervals.
Again, the occurrence of organic remains in the different beds of
this formation, is like the alternation of the strata composing it, ex-
ceedingly irregular: sometimes they occupy the clay, at other times
the sand or pebbles, and very frequently are wanting in them all.
A good example of shells occurring, mixed with large pebbles,
300 The Rev. W. BuckLanD on the Plastic Clay Formation.
may be seen at Sundridge Park, near Bromley, in Kent, where we
find an immense deposit of shells, peculiar to the plastic clay for-
mation, accumulated confusedly in a bed of loose sand and pebbles.
Of these shells some are broken and others entire, and delicately pre-
served, They are aslo sometimes fixed together by a calcareous
cement (derived apparently from the substance of the shells them-
selves) forming a hard breccia with the siliceous pebbles and sand
in which they are imbedded. A similar breccia was sunk into
in the workings of the Redriffe tunnel.
Ihave from this bed at Bromley a specimen, in which five oyster
shells are so affixed to the opposite sides of a large kidney-shaped
pebble, that they seem to have commenced their first growth on it,
and to have been attached to it through life, without injury by fric-
tion from the neighbouring pebbles. We cannot but infer then that
these pebbles received their form during a long period of agitation,
which was succeeded by a period of repose; in which latter they
were in a state of sufficient tranquillity for the shells in question to
live and die undisturbed in the midst of them.
The enormous quantity of these completely rolled and rounded
chalk flint pebbles * that occur in the English plastic clay formation
* It may be observed of these pebbles occurring in the plastic clay formation, that they
are never calcareous, but composed almost entircly of oval or roundish and rather flat
chalk flints, completely rolled down and slightly altered, sometimes to the centre, by
decomposition ; which beginning from without has produced, in some cases, a number of
concentric zones, disposed in agate like rings, nearly parallel to the outer surface of the
pebble, and resembling an agate in colour though inferior in purity. The fact that in
these pebbles we occasionally find fragments of organic remains peculiar to the chalk
formation, shews that they were not formed like agates in empty cavities. And the de-
composition of their iron commencing from the outer surface, is fully adequate to pro-
duce the concentric structure which they present; as may be seen in similar concentric
zones resulting from the same cause in pebbles of sandstone, and many other rocks, of
which the substance is compact and tolerably uniform in texture.
kee &
ge
¥
The Rev. W Buck ianp on the Plastic Clay Formation. 301
on the south of London, corroborate the arguments adduced by M. M.
Cuvier and Brongniart, from the irregular projections and furrowed
surface of the French chalk, and from the fragments of chalk forming
a breccia with the plastic clay at Meudon, to prove the consolida-
tion of the chalk to have been completed before that partial de-
struction of its upper strata by the force of water, to which they
justly attribute these furrows and the Meudon breccia. These
English beds of chalk flint pebbles (the wreck of strata thus destroyed)
afford additional evidence of the immense scale on which this aque-
ous destruction was carried on, and confirm also the conjecture (which
by them is chiefly grounded on the total difference of the organic
remains in the two formations) that a long period of time has pro-
bably intervened between the deposition of the chalk and the plastic
clay.
More frequently the pebbles aro clouded with tints of red and yellow, presenting an
indefinite variety of beautiful modifications, and assuming the irregular arrangement of the
colours in an Egyptian pebble. The finest varieties of these colours are displayed to the
best advantage in polished specimens of the Hertfordshire pudding-stone, so common in
cabinets and ornamental jewellery. The pebbles of this pudding-stone appear to be no
other than altered chalk flints of the same era with those found at Blackheath, and differ-
ing only in the accident of their being firmly united by a strong siliceous cement. Many
of the purest varieties of the Blackheath pebbles if polished, are exactly similar to those
of the Hertfordshire pudding-stone. ;
Large blocks of a coarse variety of the same siliceous pudding-stone are not uncom-
mon on the surface of the chalk in the south of England. I have seen them at Braden-
ham, near High Wycombe, at Nettlebed, at Portesham, near Abbotsbury, and in Devon-
shire, lying insulated on the bare chalk. They have not yet I believe been found im-
bedded in their native stratum, which seems to have been destroyed extensively above
the English chalk, and to have been a member of that series of irregular alternations of
beds of clay, sand, and gravel, either separate or mixed together, which for reasons
already stated, has been designated by the appellation of the plastic clay formation.
Wom, L¥. 2a
—
J02 The Rev. W. BuckLanp on the Plastic Clay Formation.
APPENDIX.
Ir may not be uninteresting to insert here the following notices,
illustrative of the formation of the marsh lands immediately below
London, which, though not directly connected with our subject, the
plastic clay, yet forms a prominent feature in the physical history of
that part of the neighbourhood of the metropolis which we have
been describing.
It is well known that at this time the waters of the Thames from
London to the sea are upheld by dykes or sea walls. Within these —
dykes the river by its daily sediment of mud has so raised its bed,
that even in ordinary tides the water is above the level of the mea-
dows, as far up as Woolwich and the Isle of Dogs. This elevation
of its bed is precisely analogous to what has happened near the _
mouths of the Po, the Rhine, and other large rivers, which have
been upheld for many centuries by embankments. The following
facts tend to illustrate the process that was going on before the pe-
riod at which these embankments were made.
In the account given by Capt. J. Perry, about 100 years ago, of the
stopping of the breach made in the sea wall at Dagenham, about twelve
miles below London, that able engineer particularly describes what he |
calls moor log. This, he says, was composed of vegetable matter
heaped together, but chiefly of brushwood, among which there ap-
peared to be a considerable quantity of hazel trees ; hazel nuts were
also found in the mass, but were easily crushed, the kernel being en-
tirely perished. ‘There were also trunks of other trees, of which the
yews were the least decayed; some of them measured 15 or 16
inches in diameter. There were also willows two feet and upwards
The Rev. W. BucKLANnp on the Plastic Clay Formation. 303
in diameter; they retained a whitish colour like touchwood, and
were softer than the adjacent earth or moor log. The moor log
appeared at about three or four feet under the marsh ground, and
differed in thickness at different parts; at Deptford it was six feet
thick ; at Woolwich Reach, opposite the ballast wharf, it was be-
tween seven and eight feet thick ; its thickness as well as its breadth
gradually increasing down the river. Beneath the moor log was a
stratum of blue clay, and under this gravel and sand. Stags horns
were likewise found in different places, a little above the vein of
moor log.
Mr. Derham’s account of the Dagenham marsh land (Phil. Trans.
1710, p. 478), affords the following particulars in addition to those
given by Capt. Perry.
The stumps and roots of many trees were found in the same
posture in which they grew, situated in a soil consisting of a black
oozy earth, full of the roots of reeds; the tops of these stumps
were so worn that it could not be ascertained whether the bodies
had been cut off by the ax, or broken by natural violence. The
bodies themselves lay horizontally on the surface of the oozy earth,
in confusion, but a northerly direction seemed most prevalent.
They appeared almost all of them to have been alder, though at
first they were supposed to be yew. Over the trees lay a covering
of grey mould, of the same nature with the sediment of the Thames
at this day, varying in thickness from seven to twelve feet. Mr.
Derham mentions the names of the following places in which he
noticed traces of this subterranean forest. Dagenham, Havering,
Rainham, Wennington, Purfleet, West Thorrock.
It happened a few years ago that in cutting the canal and basins
in the Isle of Dogs, a subterranean forest containing hazel nuts, with
2 OF2
304 The Rev. W. BucKLANp ox the Plastic Clay Formation.
hazel and other trees, was discovered to lie under the bed of indu-
rated mud, that forms the surface of that peninsula.
These data throw much light on the natural operations that were
going on, between the period of the last retreat of the diluvian
waters, and that at which sea walls began to be erected against the
rising waters of the Thames. The substratum of clay and gravel
mentioned by Capt. Perry, formed the first surface of the valley
uncovered by mud or water, and lying at a small elevation above
the then existing high water level of the river. The sediments of
the river gradually raised its bed, and caused its waters to spread
laterally over the adjacent low lands; first converting to marsh
by inundations at high tides, and at length completely burying, by
its daily sediment of mud, those tracts which in the early periods
of the rise of the bed of Thames, had been quite dry and covered
with extensive forests. The horns of stags that inhabited them lie on
the surface of the moor log, which appears to be the wreck of these
ancient forests, first converted to swamps as the water began to
reach their level, at length wholly destroyed by the constant inun-
dation of the ground on which they grew, and still affording evi-
dence of their position and extent, in the roots and trunks that lie
buried on the surface and in the mass of the moor log, and over
which a bed of mud has subsequently been deposited by those gra-
dually rising waters which caused the destruction of the forest.
XVI. Ox some Beds of Shell-Marle in Scotland.
By HENRY WARBURTON, Esg. F.r.s.
VICE PRESIDENT OF THE GEOLOGICAL SOCIETY.
{Read January 21st, 1814. ]
Tue late researches of Messrs. Cuvier and Brongniart in the
vicinity of Paris, and those of Mr. Webster in the Isle of Wight,
have made known to us a new series of beds, of which the most
remarkable consist almost entirely of the shells of freshwater mol-
lusce. An instance of analogous recent accumulations will not, I
hope, be undeserving of the Society’s attention.
The Rev. James Lambert, of Trinity College, Cambridge, has
supplied me with most of the following particulars, which have
been chiefly abstracted from the returns made to that gentleman’s
enquiries by some respectable land agents and proprietors in the
neighbourhood of Dundee.
The beds of shell-marle are chiefly found in the shire of Angus,
in the several parishes of Kerrymuir, Airlie, Forfar, Rescobie,
Meigh, Newtigh, Abermo’, and Lundie, lying from eight to twenty
miles north-west or north-east of Dundee. They are also known
in the shires of Perth and Ross, and south of the Tay in the shire
of Fife near to St. Andrew’s, and of Berwick near to Kelso.
The shells, which, by the kindness of Mr. Lambert, I am enabled
to present to the Society, were taken from a bed of marle lying on
306 Mr. WARBURTON on Shell-Marle.
the estate of Mr. Cleghorn, about four miles south of St. Andrew’s.
This bed is found in a piece of swampy ground, at the bottom of
a natural hollow, in attempting to drain which the marle was dis-
covered. It is entirely covered by moss, and also rests upon moss,
of which a specimen, taken from beneath the marle, accompanies
the shells. In the middle of this hollow the marle is five feet thick.
Logie lies in the parish of Kerrymuir, between Glamis and For-
far. The following succession of beds has been discovered on cut- ©
ting trenches for obtaining the peat mosses. Moss, containing |
trees, from four to six feet thick; shell marle, from six to seven
feet; blue clay; shell marle, nine inches thick; gravel or quick
sand, and sometimes a third bed of marle.
These beds of marle are continuous, and extend over many acres;
they are thickest in the middle, and become gradually thinner to-
wards the edges of the bogs.
The marle of Logie, as well as that from Fifeshire above de-
scribed, consists almost entirely of the shells of the Helix putris,
such as are the specimens presented: myriads of this species are
now found living in the brooks that flow through the bogs of
Logie. Living specimens of the Mytilus cygneus, equal in dimen-
sions to those mentioned by Montagu, and occasionally containing
fine pearls, are found in the same brooks: of this shell the marle
also contains fragments.
Not far from Logie, in the parish of Forfar, are the moss and
loch of Resteneth, which about the year 1794 were entirely
drained by a cut made into the loch of Rescobie, lying at the dis-
tance of half a mile on a lower level. Both the moss and loch
contain shell marle: that in the moss is covered to the depth of
five or six feet by fine black peat, that in the loch not unfrequently
so. The marle does not lie in a horizontal bed, but shelves from
Mr. WARBURTON on Shell-Marle. 307
the middle of the loch, where it is eleven feet thick, to the edges of
the moss, where it does not exceed in thickness a few inches.
The marle of Resteneth consists of the shells belonging to the
Helix putris (Pennant), (peregra Montagu), and the Cardium am-
nicum (Mont.), both which are now found living in the waters
that flow through the loch. Neither of these in size much exceed
a pea; yet not less than two millions of cubic feet of marle had
been dug between the years 1794 and 1807 for agricultural pur-
poses.*
Resteneth loch lies about twelve miles distant from the sea at the
level of 196 feet above low water mark. It gives rise to a con-
siderable stream, which flows into the sea about thirteen miles east
of the loch, after forming in the three first miles of its course the
lochs of Rescobie, Balgarvie and Balmodin, in all which shell marle
is obtained by dredging with boats ; in the loch of Rescobie at the
depth of 25 fathoms. |
Lord Duncan’s loch is situated in the parish of Lundie, eight or
nine miles north-west of Dundee. It covers an area of seventy
acres, of which fifty have been drained, and from which shell marle
is dug, as in that of Resteneth.
In al! these places we have the same appearances ; the marle al-
ways occupying some natural hollow or basin, which either is or
has been the site of a pool of water. In Resteneth loch we have
’ * The shell marle in an economical point of view is of some importance. On the estate
of Mr. Cleghorn, from an area of half an acre, a quantity has been raised that would have
cost £2500. if procured from St. Andrew’s, after being imported thither from the shire
of Angus. At Resteneth it is dug with the spade, and sold to farmers at 2d. the cubic
foot, from two hundred and fifty to five hundred cubic feet being laid on the English
acre. That which lies immediately under the moss is reckoned the best. Some mention
of the economical use of shell marle will be found in the Statistical Survey of Scotland,
under the heads of several of the above mentioned parishes,
308 Mr. WARBURTON on Shell-Marle.
the complete history of one of these accumulations. A pool of
water is peopled by myriads of little animals, with whose exuviz it
becomes gradually filled, and thus beds are raised and fitted for
vegetation. Water and land plants arise and decay, and in a humid
soil a peat bog is formed; perhaps (as has happened at Logie) the
outlet of the water is again choaked, and the same effects renew in
the same order.
The calcareous beds thus formed are, it is true, on a small scale,
when compared with those of the Paris or Hampshire basins. Yet
contrasting the insignificance of these little testaceous animals with
the space occupied by their exuviz, which at Lundie, for instance,
is many feet deep and covers an area of seventy acres, the extent
of their beds is surprising. The siticeous beds indeed, and the
porcelanic limestone of the Paris basin are wanting to this recent
formation, and are still problems for geologists to solve; but in
respect of the quantity of shelly matter the analogy is perfect, and
the imagination can readily seize the effects produced in a warm
and prolific climate with animals of decuple dimensions, and with
a liberal allowance of time.
Since shell marle is not common to all the Scotch lakes, it might
be worth inquiry what peculiar circumstances favoured its pro-
duction ; whether calcareous salts are particularly abundant in the
waters that yield it; and what are the rocks from which those
waters spring, or which form the sides of containing basins. The
water of Resteneth is said to be remarkably clear.
There is no limestone near to Logie, except in a small vein, dis-
tant therefrom two miles, at Readie in the parish of Airlie. The
predominant rock about Resteneth is a sandstone of a brown, red, or
whitish grey colour, which alternates with a coarse ferruginous pud-
ding stone. Whin-dykes, and veins of barytic spar, occasionally tinged
Mr. WarsurtTon on Shell-Marke. 309
with copper, intersect this rock. From the northern edge of the
loch rises a considerable hill, called Pitscanellie hill, composed en-
tirely of grit-stone, whose different beds, alternating with a coarse
breccia, furnish stones for slating, paving, mill-stones, and rubble
work. From the south side of the loch rises a hill of freestone,
whose summit is covered by whin, This bed of whin is of no
great breadth, and extends about two miles in length, from one
end of the ridge to the other. If we may guess from this de-
scription, the prevailing rock seems to be the red sandstone, so
common in this island ; it is in basins formed in this rock that the
shell marle is found in the vicinity of Kelso.
VOL. IV. ie
XVII. Geological Remarks on the Vicinity of Maestricht.
By the Rev. W. E. HONY, Fellow of Exeter Coll. Oxford.
MEMBER OF THE GEOLOGICAL SOCIETY.
Read 16th December, 1814.
Tue interest excited by the magnificent specimens which have
been discovered at different times in the neighbourhood of Maestricht,
induced me when in the Low Countries in the summer of the pre-
sent year, to go somewhat out of my way in order to visit so cele-
brated a spot. I am sorry that my stay there was necessarily so
short that I could take only a very hasty survey of that country.
I am induced however to lay before the Society a short sketch of
what I saw, because I believe that though so much has been written
and said on the subject of the fossils of Maestricht, but little is
known in England as to the relative situation of the strata contain-
ing them. The mountain of St. Pierre commences about a mile south
from the town of Maestricht, and extends in a direction towards
Liege for nearly three leagues. It is an insulated hill forming a
ridge, the sides of which are for the most part very steep. The
subterraneous quarries must have been worked from a very early
period, and are said to extend through its whole length. The hill
presents an almost perpendicular escarpment towards the Meuse,
and it is in walking on this side of it that the strata are seen to the
greatest advantage.
The Rev, W. E. Hony on Maestricht. 311
About a league from Maestricht you obtain a good section of
the lower beds of the hill, and these are decidedly chalk, containing
beds of flint nodules from two to three feet distant from each other.
The chalk appears to contain fewer fossils than that which we have
in this country, but in the nature of these fossils, and in every
other respect, completely resembles it.
Above these are beds resembling the chalk in colour, but more
hard and gritty to the touch.
Above these again lie a succession of beds of the calcareous free-
stone of which the mass of the hill is composed, and it is in these
that the quarries are situated. This stone is of a yellowish colour,
and so extremely soft in the quarry that it may be easily cut with
a knife; it becomes however of a lighter colour and more hard by
exposure to the air. Here and there is found a thin stratum com-
pletely made up of fragments of marine substances ; these are chiefly
species of corallines and madrepores mixed with shells. In these
thin strata the remains are much less perfect than in those which
contain fewer of them, and their substance is so extremely tender
that it is very difficult to obtain a specimen which does not break
to pieces immediately. Such parts of the rock, though of course
unfit for building, are not useless, but are broken down, and in that
state conveyed by the Meuse to Holland as a manure for the
meadow land.
The whole of these beds from the chalk to the top of the hill
are separated from each other by beds of flints, which exactly re-
semble those found in the chalk, presenting like them the usual
appearance of having been formed on corallines, &c.
The beds of flints in the chalk and lower strata of freestone, as
has been mentioned, are at a distance from each other of not more
than two or three feet, but as you ascendd, thesistance between
aha
312 The Rev. W. E. Hony on” Maestricht.
them is greater, and towards the upper part of the hill is as much
as eight or ten feet.
These flints frequently contain organic remains; of these the
most common is the belemnite; shells also and silicified wood are
not uncommon.
The height of the hill above the Meuse is I should imagine
about 150 feet.
To the eye the strata appear to be perfectly horizontal. As
however, I found the chalk gradually rising as I proceeded in a
direction nearly south, it is probable that there may be a very
slight inclination towards the north. My stay was too short to
enable me to give any account of the numerous fossils of this rock.
I may however mention that those which I found most common
were various species of corallines and madrepores, (particularly the
fungites ;) belemnites ; numulites ; several species of echini, amongst
others, a small one having the mouth in the centre of the base and
vent lateral ; several kinds of oysters and pectines. I was also for-
tunate enough to find a very beautiful baculites with turrited articula-
tions, but this I believe is very rare. Itis described in the 3d vol.
of Parkinson’s Organic Remains, p. 142.
The top of the hill is covered by a bed of gravel, in some places
of considerable thickness, containing rolled pebbles of flint, white
quartz, graywacke containing veins of quartz, and a red sandstone.
I believe that this gravel rests immediately on the strata which
compose the hill, and that the beds of sand which M. Faujas de
St. Fond thought he perceived under the gravel are only a part of
the rock in a state of decomposition.
It is rather extraordinary that this celebrated naturalist should
have described the freestone rock of Maestricht as “ un grés
quartzeux faiblement lié par un gluten calcaire.” It appears that
The Rev. W. E. Hony on Maestricht. 313
it is almost wholly calcareous, containing little or no siliceous
matter. .
Geologists will of course be anxious to learn whether these beds,
occupying a situation similar to that of the Paris strata, are identical
with any of them. I am myself too little acquainted with the
latter to form any opinion on the subject. I am inclined to think
however that the Maestricht rock differs from all the beds which
form the Paris basin.
It would be departing too much from common language to call
it chalk ; but the gradual transition of the chalk into the freestone,
and the separation of the strata from each other by parallel beds of
flint, seem to be sufficient reasons for including it in the chalk
formation.
When nearly at the southern extremity of St. Pierre I crossed
over to the right bank of the Meuse to examine a rock which rises
very boldly near a little town called Vise. This rock I found to
resemble the limestone of Derbyshire, containing all the fossils
characteristic of that formation, and like it frequently passing into
chert. The fossils most abundant are several species of anomiz
and entrochi: the latter are more particularly abundant in the
chert. In some pieces I also found that species of coal which is
called anthracite included in veins of calcareous spar.
In the country round Liege, distant about two leagues S.W. of
this place, there are (as is well known) extensive collieries,
XVIII. Ox the Parallel Roads of Glen Roy.
By J. Mac Cutrocn, M.D. F.L.S.
PRESIDENT OF THE GEOLOGICAL SOCIETY,
CHEMIST TO THE ORDNANCE,
LECTURER ON CHEMISTRY AT THE ROYAL MILITARY ACADEMY,
AND GEOLOGIST TO THE TRIGONOMETRICAL-SURVEY.
[Read 3d January, 1817. ]
Tue extraordinary and hitherto solitary phenomena which I
have undertaken to describe, although long known and celebrated
by the natives as the traditional works of their great ancestors, re-
mained concealed from the world in general till Mr. Pennant pub-
lished a short account of Glen Roy in an appendix to his Tour.
A second description appeared in the Statistical Survey of Scotland,
since which I know not that any attempt has been made to explain
the origin of the Parallel Roads, although they have long been
objects of curiosity to philosophical as well as to ordinary tourists.
However convinced the Highlanders may have formerly been that
these parallel roads, as they are called, were the works of Fingal
and the heroes of his age, they have lately inclined to a different
belief, and with most philosophers are willing to think that they
may have been the result of the action of water. Still the matter
remains disputed among the partizans of the different theories, and
as the establishment of the latter opinion is attended with geological
consequences of the first importance, it deserves to be investigated
with the greatest care.
Dr. MAc Curocu on the Parallel Roads of Glen Roy. 315
The appearance of the parallel roads is so extraordinary as to
impress the imagination of the most unphilosophical, nay, even of
the most incurious spectator. It is not therefore surprising that
they should excite the admiration of the natives, in whom the
progress of civilization has not yet extirpated those poetical feelings
and that sense of the sublime, of which their literary relics still
afford us proofs.
On each side of a long, hollow, deep valley, bounded by dark
and lofty mountains, and at a great elevation, three strong lines are
traced, parallel to each other and to the horizon, the levels of the
opposite ones coinciding precisely with each other. So rarely does
nature present us in her larger features with artificial forms, or with
the semblance of mathematical exactness, that no conviction of the
contrary can divest the spectator of the feeling that he is contem-
plating a work of art, a work, of which the gigantic dimensions
and bold features appear to surpass the efforts of mortal powers.
We cannot therefore wonder that the solitary and poetical High-
lander, educated amid mountain storms and hourly conversant with
the sublime appearances of Nature, should attribute to the ideal and
gigantic beings of former days a work which scorning the mimic
efforts of the present race, marches over the mountain and the
valley, holding its undeviating course over the impassable crag, and
the destroying torrent.
But it is the duty of the philosopher to investigate causes. I
purpose therefore to give as ample and detailed a description as I
was able to draw up, of the appearances themselves, and afterwards
to examine the several modes of explanation which have been
offered ; stating the arguments for and against the different hypo-
theses as amply and as distinctly as I can, and deducing from the
balance of probabilities such conclusions as the evidence appears to
316 Dr. MAc Cuxrtocn on the Parallel Roads of Glen Roy.
justify. The necessity of investigating their probable or possible
origin from natural causes will, in consequence of the extent of
their geographical connections, lead to rather a wide range of
enquiry, not however wider than the importance of the subject
will be found to justify. I have attempted to keep clear of all spe-
culations purely hypothetical, and wherever physical evidence and
analogy have entirely failed, have rather chosen to leave the ques-
tion in its natural obscurity than to involve it in more profound
darkness by assigning imaginary causes. ‘To avoid any bias which
the original and not sufficiently descriptive term, Parallel roads,
might preserve in the reader’s mind, I have substituted that of
Lines, a term less exceptionable and sufficiently expressive of their
appearance.*
* I think it right to remark that every precaution was taken in ascertaining both
the levels and the elevations which will be referred to in the arguments hereafter to be
used. Those which could not be accurately determined, on account of the nature and
extent of the ground reauiring a survey, have been estimated by such approximations as
were attainable, and these are distinguished wherever they occur. However imperfect,
they are no where so lax as to affect the arguments, even if the errors were much greater
than any which could have occurred, as no undue stress is any where laid on hypothetical
assumptions. The levels of the dines were observed by a spirit level, and the vertical
distances between them were measured by the same instrument. One barometer of
Ramsden’s construction was applied for the measurement of the elevations; and-such
differences between any two altitudes as were required, were ascertained by observations
repeated at very short intervals, For determining the absolute altitudes above the level
of the sea, the barometric observations weré compared with a register kept purposely for
these experiments by Lord Gray at Kinfauns Castle, those observations, with the required
corrections, being made at the same hours with instruments of similar construction. To
remove still more any chance of error, the principal altitudes were deduced from a medium
of nine observations taken on four different days, the greatest variations between the ex-
tremes not exceeding one twelfth of the whole. The altitude of the great Caledonian
valley is known from the measurements belonging to the canal.
Notwithstanding all this care however, I can only consider these altitudes as approx-
imations, since I am convinced froma careful comparison of barometric registers that this
instrument cannot be relied on when used in this manner, as I have attempted to show in
a late communication to this Society.
Dr. Mac Cuttocu on the Parallel Roads of Glen Roy. 317
Before examining any of the theories which have been proposed
to explain the singular appearance which this glen exhibits, I have
judged it expedient to describe with as much accuracy as possible
the appearances themselves, without entering on the question of
causes, or prejudging in any degree the case. In thus describing
it, I have preferred beginning at the source of the river, or rather
at the commencement of the valley, since the rivers which form
the Roy arise as mountain torrents, forming a junction in the middle
of a valley of considerable magnitude.
A low hill of granite skirts the boundary between the source of
the Spey and’the valley of the Roy. At the foot of this hill, in a
slightly elevated boggy plain, is found Loch Spey, which by a
declivity for some time scarcely perceptible runs eastward through
Badenoch to fall into the Moray firth. The western end of the
boggy plain just mentioned stretches for a few hundred yards
beyond the head of Loch Spey, and then descends by a sudden step
into the upper valley of Glen Roy. This valley is of an oval form,
The principal map does not pretend to be an accurate survey. The defective nature
of all the maps of Scotland hitherto constructed, as well as the smallness of their scales,
prevented me from making any use of them for this purpose; but as the description
would have been unintelligible without some sketch of the ground, [ have given one
which must however be considered merely in the light of a military reconnoissance.
The sections do not pretend to be real. The transverse ones are, like the map, delineated
without attention to their true proportions, and are merely intended to mark the impor-
tant variations ef the form of the bottom of the valley, and more particularly the points
in which the dines and the terraces coincide. ‘The curved longitudinal sections are equally
artificial, but they assist the imagination in pursuing the wide connections of Glen Roy
with the sea. The profiles of the dines are deduced from actual measurement by the
spirit level,
Of the accompanying views I need only say that they are intended to elucidate several
parts of the description, and to convey a slight notion of the nature of the appearances
in question. The purposes of the two other maps in shewing the connections of Glen
Roy with the neighbouring and with the more distant country will be ebvious.
VoL. Iv. os
318 Dr. Mac Curttocn on the Parallel Roads of Glen Roy.
about four miles in length and one or more in breadth, being
bounded on two opposite sides by high mountains. From them
descend two streams which unite about the middle of the valley to
form the Roy. Fiom this junction the water flows with a mode-
rate velocity for a space of two miles, when the glen suddenly con-
tracts and terminates in a rocky hill of low elevation. The water,
forcing its way for some distance through a narrow pass between
approaching rocks, enters into a second glen, which I shall dis-
tinguish by the name of the lower Glen Roy. It is in this latter
glen that the phenomenon of the roads is chiefly to be seen, nor on
entering the upper from the lower one would it be suspected that any
similar appearance existed in it. A die however may be observed
on the left hand extending upwards from the junction which forms
the Roy, along the face of a low hill towards the elevation in which
Loch Spey lies. A careful examination of this /ime by the spirit
level shows it to consist of a level narrow terrace, which if prolonged
eastward would cut the perpendicular above Loch Spey, and if
continued westward would meet the summit of the flat rock that
forms the division between the higher and lower Glen Roy. It
will speedily be seen that this summit is on a level with the upper-
most of the /:mes in lower Glen Roy, and that the terrace which I
have now described is in fact a prolongation of that dime. It is
necessary to remark that no other terrace or /ime is found in the
upper valley.*
The flat rock already mentioned as forming the gorge of lower
* The map, Pl. 20, is copied from Arrowsmith’s work, and contains various dines
supposed to be seen in the adjoining vallies. I have retained them iu all the places which
I had no opportunity of examining, without intending to be responsible for their exist-
ence. Where they did not agree with my own observations [ have without scruple
omitted or altered them.
Dr. Mac Cuttocnu on the Parallel Roads of Glen Roy. 319
Glen Roy, or the division between the upper and lower vallies, is
seen projecting at right angles to the right hand side of the glen,
and then turning westward so as to form a promontory parallel to
that side; having a cul de sac on one hand and giving passage to
the river on the other. No /me is visible on the rock itself, but
from its junction with the side of the valley (as the plan will show)*
the two dies commence, and are seen running on far along the
face of the hill, the uppermost one being precisely even with the
flat parts of the surface of the rock just described. It is proper
here to remark that the surface of this rock rises higher in some
places than that /e, yet it is not marked by any corresponding
one. The drawings accompanying this paper will render intelli-
gible that which words alone cannot describe; and I must here
premise once for all, that this minuteness of description, however
superfluous it may at first sight appear, is absolutely required, as
the circumstances thus dwelt on will be of essential use in investi-
gating the cause of the appearances under discussion. It is by an
attention to circumstances which at the first glance appear trivial,
that abstruse truths are often discovered ; and it is precisely where
leading and obvious phenomena offer no clue to guide us, that a
ray of light will often be thrown on the subject from appearances
at first neglected. Had the greater features of Glen Roy been
capable of explaining the singular phenomena which it exhibits,
this paper would have perhaps been altogether superfluous, since
all observers would have been agreed respecting their causes.
These level and parallel ines are scarcely to be seen in this place,
except by looking from \below upwards, a position by which they
are foreshortened to the spectator’s eye. They may sometimes
* Plate 18.
232
$20 Dr. Mac Cuitocusy on the Parallel Roads of Glen Roy.
indeed be distinguished (but with more difficulty) if viewed in
profile. In the part which I am now describing the dines are narrow
and the declination of their surfaces from the horizontal plane is
considerable, as the profiles* will show. This ground is rocky and
irregular, the natural rock being visible in many places, while in
the rest of the glen it is but rarely seen; and it may be remarked
that wherever the natural rock comes to light these marks or /ines
are always least discernible, being of much smaller dimensions, and
having a much greater conformity in their slopes to the natural
slope of the hill. Whatever loose matter occurs here consists of
large fragments, which have evidently descended from the hill
above. That this is their origin and that they are not transported
materials is plain, since they are not rounded and since they exactly
resemble the natural rock, which is of a remarkable character, con-
sisting of mica slate traversed by numerous veins of red granite; a
rock which is limited to the upper part of the glen and is not
found in the neighbouring hills. The natural rock projects in
many parts of the /ime so as to interrupt it; or it is wanting
wherever a solid mass of rock occurs in its course. As I am
here only describing the appearances, [ will not anticipate the
arguments by asking whether the /éve has not been sometimes over-
whelmed by the fall of rubbish ; in many cases however its obscu-
rity evidently arises from the refractory nature of the materials on
which it is traced. Obscure marks of two similar /mes are here
and there visible on the left hand side in this place, particularly on
certain projecting faces where the surface of the hill is, from its
outline, evidently covered with a coat of alluvial matter. Indepen-
dently of these fragments of the two principal lines, many short
indistinct traces are to be seen at different levels from those on
* Plate 18, Profiles No. 3, §.
Dr. Mac Cuvziocn on the Parallel Roads of Glen Roy. 321
which these two lie. It is here necessary to say that the two /ines
on the right now described are parallel to each other, and corre-
spond precisely in level with the fragments of the two upper ones
visible on the opposite side.
As we proceed down the glen a river is seen entering at the left
hand equal in size to the Roy, and falling into it by a cascade which
rushes over a rocky bed. Here a great series of terraces is found,
forming a large ferreplein at the top of this glen which I have
called lower Glen Roy. These terraces are of different levels, as
may be seen both in the section* and in the views that accompany
this paper.f The highest of them will hereafter be proved to lie on
a level with a third /zze, to be described in the course of this in-
vestigation. It falls off however by many successive stages of
terraces, and numerous smaller ones are also to be seen descending
down to the very bed of the river, skirting its banks and accom-
panying its course. The bottom of the glen is here an alluvial flat,
as the above mentioned section will show. Between the two upper
fines on the right hand an intermediate one now becomes visible
for a space of about half a mile: I did not measure it, but to the eye
it appears equidistant from both. At this point the two dimes now
described suddenly quit the rocky face described on the right hand,
and continue their courses along the alluvial slopes of the declivities
which follow; where also they acquire their greatest breadth and
distinctness.
I forbear giving the breadths in all the places where I measured
them, because it is not important. The profiles will show the
principal varieties.f In detailing their measures I must remark that
it would be impossible to describe the precise geographical point
measured, and such often is the curvature at the entering and salient
* Sect. L, Plate 21. + Plate 14, 15. t Plate 18.
$22 Dr. MAc Curtocu on the Parallel Roads of Glen Roy.
angle, or at the inner and outer edge of the /ime, that no precise
limit for the measure of breadth can be assigned; different modes
of measurement may therefore produce differences of many feet.*
It is sufficient if they agree generally, and in general sixty feet may
be assumed as an average breadth: by far the largest portion cf all
the /ines will be found to conform to this measurement,
Great terraces are now visible on the right. These are not pre-
cisely on the same level with that which I before mentioned as
corresponding to the course of a third and lower dime, but they do
not differ materially from it.
I shall not describe the various rivers which enter the glen, the
principal ones being marked in the plan, but may mention that in
this upper part of the valley, both before and at the junction of
Glen Turit with Glen Roy, they are generally accompanied by
their own lateral terraces.
On the left hand going down the glen many marks or fragments
of dimes are seen between the principal ones; but these are short,
and are remarkable for many obscurities and deficiences. In a few
places there are errors of level to be seen in the Zmes. Examining
these however there appears no doubt of their having been pro-
duced by partial subsidences of the whole alluvial face; and this is
confirmed by the appearance of one great slide on the left, which
has descended many feet, and which the imagination can readily
replace. It is necessary to be cautious in examining these instances
of errors of level, as the laws of perspective are apt to lead to
mistake when the /izes pass curved surfaces elevated high above the
horizon.
Where the faces of the hills have been furrowed by the long
continued action of descending torrents, the /zes enter these hollows
* Plate 18, Profile No. 8.
Dr. Mac Cuxiocu on the Parallel Roads of Glen Roy. 323
for a certain space; and as this rule is general, it is unnecessary
either to describe the spots or to mark the exceptions, but the fact
itself is important. They are often ploughed across or obliterated
by torrents obviously recent; and they sometimes also terminate
abruptly in more ancient torrents; but still the two upper ones
continue generally traceable and commonly very well marked: for
the rest | must again refer to the plan.* From these appearances
we can often ascertain the relative difference of age between the
hollow or torrent and the /ive: and we can also in some cases dis-
tinguish that a part of one hollow is prior and a part posterior to it.
It may be remarked generally that the mes are best marked on the
straightest sides, or on those slopes which lie in a straight or a
slightly curved plane, while they are most obscure where the most
numerous sinuosities, torrents, irregularities, or rocky faces occur.
Among the best marked are the two uppermost ones on the right
hand above Glen Turit, one of those at the head of Glen Turit, and
the three above Glen Fintec on the same side. About two miles below
the head of lower Glen Roy, a semi-circular cory or hollow opens
on the right, giving rise to a considerable stream and falling gra-
dually into Glen Turit. The two upper /imes (for as yet there are
no more) enter it a little way and then disappear. On its opposite side,
‘or that which adjoins to Glen Turit, appear three marks offering
the only considerable anomaly in the whole course of these “ines.
The two uppermost, which on a superficial view seem to be the con-
tinuation of the two before described, will be found more distant
from each other than these, and on applying the spirit level to
them it is seen that the lowest is continuous with the upper one of
Glen Roy, but that the highest is a supernumerary one, although
of the same apparent dimension and form, and that it terminates
* Plate 18.
324 Dr. Mac Cuttocu on the Parallel Roads of Glen Roy.
abruptly at both ends. That one which is continuous with the upper
line of Glen Roy is prolonged into Glen Turit. Of the lower one
I unfortunately neglected to remark, from the multiplicity of ob-
jects calling for attention at the same time, whether it was anomalous,
or whether, as it appears to the eye, it is not continuous with the
third and lowest in Glen Roy. I shall forbear pursuing their
course into Glen Turit, as the description of this glen will find its
proper place hereafter.
Passing over therefore the description of this glen, a great accu-
mulated mass of terraces similar to those in the upper part of Glen
Roy is seen at the junction of the two streams which issue from it,
and from the small glen or cory whose name I could not discover,
but which is delineated in the map.* The compound mass offers
a surface of different heights, but the highest of them corresponds
precisely in level with the highest terraces at the top of Glen Roy,
and equally so with the lowermost /ize of the three for which Glen
Roy is remarkable, and which now first appears continuously on
the right side, having been some time visible, though in an imperfect
state, on the left. ‘The minor terraces which skirt the river are also
visible here, and accompany it for a considerable space downwards
along the bottom of the glen, which still continues to present an
irregular alluvial flat; but as it is sufficiently marked in the plan
and sections, 1 need not enter into further details respecting it.f
The accompanying views{ will also afford an additional and a much
better illustration than any description could do.
Independently of these compound and minor terraces which are
accumulated below the lowest /zme, there are also fragments and
parts of irregular terraces in various places at a level above it,
besides considerable channelled alluvia forming a sort of conoidal
* Plate 18. + Sect. K, Plate 21.——Plate 18. + Plates 14, 15.
Dr. Mac Cutiocu on the Parallel Roads of Glen Roy. 325
segments on the faces of the hill, and appearing to be the remains
of more regular terraces furrowed and destroyed by the mountain
torrents. Although the two upper /imes are to be traced at the
salient angle opposite to Glen Turit, they are interrupted and ob-
scure to the very top of the valley. It is important to remark that
the glen here takes a turn,* forming a considerable angle, the
opening of Glen Turit being not far from the re-entering one.
At the salient angle the lowermost /ie is first seen, as on the right
side it first is found at the entrance of Glen Turit, into the wide
opening of which it runs, together with the upper ones, for a very
short space; the whole of them speedily disappearing on this side
of that glen, while on the contrary side the upper one runs well
marked until its course is suspended by the gradual rise of the
bottom of the valley.
Having, at this part of Glen Roy arrived at the point where
three /imes on each side are visible, it is time to observe that there
is a perfect correspondence of level between the opposite pairs
- wherever they are found. Numerous trials with the spirit level
confirm the universality of this rule, and from this point of the
glen downwards to its junction with Glen Spean, I did not observe
that any one instance occurred of even the little anomalous curva-
tures which I have already mentioned as happening in the upper
part of the valley. They are in many places entirely wanting, as
the plan will show, and as will be mentioned hereafter, but where-
ever they are present they obey the law. It is to this circumstance
they owe that aspect of parallelism from which they have derived a
part of their name, but which evidently can be a parallelism only
in the vertical plane. The varying slope of the hills prevents all
* PL 1s.
VoL. Iv. QT
326 Dr. Mac Cutrocs on the Parallel Roads of Glen Roy.
parallelism in the horizontal one, and causes, as will be readily
comprehended, the distance between any two approximate ones to
vary exceedingly, a circumstance of importance in examining some
of the speculations which have been formed relating to their cause
and origin. In these circumstances it would be as useless as it would
be difficult, to give the measures of their variations. It is sufficient
to remark that the nearest horizontal distance between the upper-
most and nearest /imes may be taken at 150 or 160 feet, and the
greatest between the two lowermost and most distant ones at 1000;
an approximation sufficiently accurate for the purpose. But the
vertical distances as ascertained by the spirit level are 82 feet be-
tween the uppermost and second, and 212 between the second and
lowermost. I have omitted fractions in this measurement, because
the irregularity of the ground is such, and the uncertainty of the
true surface of the line so great, that it is impossible to determine
this point to a great nicety. The slope of each sine is likewise so
considerable, and at the same time so various, that a great variation
of this vertical distance would take place according to the point
adopted as the station of the spirit level, and I have therefore fixed
it at the middle of each ie. I need not here call the reader’s at-
tention to the distances between the uppermost /ze and the top
and bottom of the glen respectively, as these will fall more properly
to be considered when the general levels of the surrounding vallies
and outlets are examined.* For the same reasons the aspect and
materials of the dines themselves will be best considered when I
have described the mineralogical structure of the whole glen, and
particularly that of the surfaces on which they are formed.
* As a convenient reference to the reader, I have however thought proper to tabulate
in one view all the measurements relating to this subject which are in any way interesting ;
Dr. Mac Currocn on the Parallel Roads of Glen Roy. 327
Having passed Glen Turit, the three es now become distinct
and well marked on the right side, where the hill is covered with a
thick alluvium: on the opposite side they are also distinct, although
here and there slight appearances of irregularity, and supernume-
rary marks occur. The bottom of the glen continues to exhibit an
many of them being objects of general curiosity, even when not particularly connected
with this subject. FEET.
Upper line of Glen Roy, above the Western sea at Loch Hil...........--- 1262
Ditto above the German sea .........0eeeeeee A ae ee ee 1266
Lowest dine of ditto, above the Western sea ...........+4: ae er rae 976
Upper Zine of ditto, above the land at Loch Oich ..... Wnt odie gales einansed ie 1180
Lowest line of ditto, above the same ...... a pit ee Miia pies eiainis cid eines able saad See
Upper line above the second of Glen Roy.......c.ssscccccccscscscasces 82
Second dine above the lowest ditto ...... tn Oe es Ra Se ie wiseGlds ania’ “212
Upper dine of Glen Roy, above the junction of the Roy and Spean ........ 927
Lawestitte, above the same Pac. og. 00 6 sp of a grain.
2, The remainder being reduced to powder in a porcelain
mortar and exposed to diluted muriatic acid until all effervescence
ceased, there remained an insoluble residue of the original dark
colour of the limestone, which when carefully washed and dried,
weighed 10 grains; allowing therefore for the weight of the
carbonic acid and lime, after the expulsion of the water of absorp-
tion, 89% grains.
3. The supernatant acid used in this experiment being decanted,
and neutralized by the addition of an alkali, yielded no precipitate
of iron to the tincture of galls; but the prussiate of potass threw
down a blue precipitate upon which however no reliance can be
placed ; as it is well known that the prussiate of potass is not a
satisfactory test of the presence of zroz when this metal exists in an
inconsiderable portion.
4, The ten grains of dark brown powder mentioned in No. 2,
being collected, washed and dried, were exposed to the heat of a
flame of a candle urged by the common blow-pipe, when com-
bustion instantly ensued, accompanied by a lambent flame, which
continued during some seconds, the powder thereby losing its
colour and becoming white; attended also by a loss of weight,
amounting to + of a grain. Hence it is manifest that the colour
is owing to bitumen.
5. To ascertain the proportion of a/umine \which from its
chemical combination with si/ex remained insoluble in the muriatic
acid) a plan recommended by Mr. Holme was adopted. One
hundred other grains of the same limestone were calcined in a
platinum crucible, and the loss of weight owing to the expulsion
of the carbonic acid was found to equal 40 +s grains.
:
|
Dr. CLARKE’s Analysis of a bituminous Limestone. 433
6. The calcined residue being placed in muriatic acid, a solution
now took place both of the /me and of the a/umine, and there
remained at the bottom of the vessel only an insoluble portion of
pure si/ex, in the form of a white powder, which when carefully
washed and dried weighed % of a grain. Deducting therefore this
weight of the si/ex, from the weight of the sc/ex and alumine, which
remained in No. 4, after the combustion of the ditumen, the weight
of the a/umine is ascertained ; which of course equals 8 ~, grains.
From all the preceding observations, it is therefore evident that
the constituents of this LIMESTONE are as follow:
Reopen) sarestires fs. ci 26 RRA elir thi Aes UGS:
Gachone. Bed 5 hehe, is, \5 yo Shey AO 10
PAREN Hs ps Was ee fd Rhee a Bis 1BO
Siletekddy: ips ied Hed ies ve Decheo O
Bitummiemy 25934015) odie el 7) Ns) a = 2 GO
Wiatere ts ayh poset ex cdi ta surtog wo 18S
100.
And the valuable property of the mortar prepared from this
limestone, is owing to the presence and proportion of alumine; and
to its property of rapidly absorbing water.
XXIX. Barometrical Measurements.
By WILLIAM ALLEN, r.r:s.
MEMBER OF THE GEOLOGICAL SOCIETY,
[Read 19th November, 1812. |
THe following measurements were made with a single Barometer
of the construction proposed by Sir Henry Englefield, and have been
calculated according to the formula recommended by him in his
memoir on the subject, which is inserted in the 14th volume of
Nicholson’s Journal. I shall give in detail the observations made
upon Snowdon ; and of the other measurements I shall mention only
the results.
Snowdon.
Observ. Hour September 8th, 1806. Therm. Barom.
1|A.M. 9 0|Goat Inn, Beddgelert .......... 61 | 29.69 |
S| ae 1025 VL ihyn (Oader | DU PP PRR ae 61 | 29.162
3|P.M. 1 25 | Summit.of Snowdon: j., 240) = --p4l sub 9 50 | 26.164
A) ———" AO ayn Cwellyae oss soe te ae War 56 | 29.30
5 j——— A AD) DiyniCader pan: euaseeieehdee oleh 57 | 29.12
6|—— 6 0| High water-mark at Pont-aber-glas-Llyn| 55 | 29.78
7|—— 6 30}Goat Inn at Beddgelert ......... 53 | 29.6
It appears from observations 1 & 7 that the Barometer had fallen
at Beddgelert in 95 hours 0.09 inches, and from observations 2 & 5
that it had fallen at Llyn Cader in 6% hours 0.042 inches. The
descent of the mercury may therefore be estimated at about 0.008
inches an hour, for which due correction has been made in each ob-~
servation on calculating the measurements.
by Mr, ALLEN and Mr. Woops. 435
From Observations 6 and 7, the height of Beddgelert Inn above high we
Weceeemarin Ath AGolvihinsP ttn ede wha wilh wietn aed rar wee 4 = 162.7
From Observations 1 & 4, the height of Llyn Cwellyn above Beddgelert = 314,2
Bo gary capac hati Re Ora Re above the Sea -« A769
From Obs. From Obs.
I& 2. 1&5. mean,
The height of Llyn Cader above Beddgelert... | 489.3| 480.2] 484.7 feet
tonne hii OE Be A above the Sea ....] 652. 642.9 | 647.4
From Obs. From Obs.
1&3. 3&7. mean
3457.5 | 3409. | 3433.2 feet
3620.2 | 3571.7 | $595.9
The height of Snowdon above Beddgelert .. .
oy RE .-.. above the Sea .....
In the following measurements only one observation was made at
the lower station, unless the contrary is stated.
Cader Idris.
The height of the highest Peak above Dollgellau . . . Sj. jen} et Ole
The feieht of the highest of the three Heads above Dollgeliaa:. iY Ge . *2BE0
Ingleborough.
The height of Ingleborough above the Bay-horse Inn, Ingleton . . . 1881
Ingleton is 90 feet below Settle; the height of Settle has been accurately
taken, and is stated at 621 above the sea; therefore the height of
Ingleton above the seais . . ile i ee: «= 2 OST
and the height of Ingleborough anase the BER IG sc Fe gee. Ste. %s yb) ees
Whernside.
The height of Whernside above Ingleton . . . . .... =. . 1930
Ro te A BPOVE Hesea | Hoo) eee ee ats ely) SAGE
“Pen-y gant.
The height of Pen-y gant above Settle ...... ... =. « 1858
MP pin settee aDUVete Sea i) BME) 1a Jeb A ae
Shap Fells,
The height of the highest point in the road between Kendal and Shap
share ReCHONMeNMcmaie Ne Oho SoM sya) nei ee We op) iar WISE Neg Mage on Fe Ti ae
436 Barometrical Measurements
Helvellyn.
From two observations made the same day at Paterdale.—Day rainy.—
The Barometer varied ,194 in 5 hours.—The Inn at Paterdale is 24
feet above Ullswater.
The height of Grisdale brow above Ullswater . ...... =. 988
2) ee « Of Red: Paria yes aie eh ey 0S hie Rolie Gh SER ee
BY eke of thettop of Helvellyn tin'itash 4) trod dala) ave te eee
Saddleback.
Threlkeld, where the first observation was made, is 235 feet above the
level of Keswick Lake, which is 228 feet above the sea.
above Keswick Lake. above the Sea
The height of Saddleback—the Pummel . . . 2615 feet 2843 feet
the Crupper . . . 2561 2789
Skiddaw.
The Oak Inn at Keswick, where the first observation was made, is 2§ feet
above the lake, which is 228 feet above the sea.
above Keswick Lake. above the Sea
The height of Latrigg « . 2). ss 5 «+ 0} GOO feet 558 feet
a Paipcwsee of Half-way stone . . .. . ~ 1408 | 1636
eo... Of the summit of Skiddaw . . . . 2739 3017
—
Barometrical Measurements.
By SAMUEL WOODS, Esq.
MEMBER OF THE GEOLOGICAL SOCIETY.
IN the following measurements only one observation was made
at the lower station, unless the contrary is stated. They are calcu-
lated according to the formula of Sir Henry Englefield.
Feet
Branch of the Mendip hills just above and eastward of Cross; the point
appears to the eye to be one of the highest in the Mendip range.
Height above Cross.) 7c ce) a! er ivelh tet | eat hioh shh is ae da eer
by Mr. ALLEN and Mr. Woops.
437
Heights above the sex
Dunkerry Beacon, one of the highest points of Exmoor, near Minehead. Feet
Weather cloudy, with light rains. From two observations, one at
Porlock Quay, the other at Minehead Quay, the Barometer had
fallen 0,14 inches in 5 hours ; 1784
Top of Brendon hills in the road between Miughead a Subvaien ‘ 1210
North hill above Minehead . .. . Shr ei esk se 1000
Highest point in the road between Bar neal ail iectuee Sree 900
anton Church-yard, in the North of Devonshire . . . . - - 428
Exmoor, about 4 miles south of Linton; one of the highest ei on the
Beaatite side of Exmoor. . . Rede een 1608
Hill called Hangman, near Comb-Warii” BP eee ee hes 1093
Hill about 1 mile east ofthe Hangman . . . 2. . + « « e . 1168
Yester, near Okehampton, one of the highest points of Dartmoor, shou
the Inn at Okehampton, 156] feet . ...... 2 Oe
The height of the Inn at Okehampton. . . . . . . . .' 516
Hastings, Sussex.
General Roy’s station near the Windmill on Fairlight Common 588
oS 30 aio Sahe 1 watermill dry: 190
Hill above the East Clit Sythe yh Bee a ey 4 313
Castle Hill Wes ced as ae. gras gel (eee Ae 180
PagenG ie vss) 4). Dub ELE EE cig ww cee, erp te 135
Dover.
Westen Meiant ‘cout. uate ae te 382
Shakespear’s Cliff La te0h oer 5 510
Summit of Castle-hill, beyond ihe dasapike KIDD BIG Ls 390
Dorking, Surry.
Heights above the bed of the Mole.
Box-hill . . wy « = ip ¢, ae, BOUL
Headley Church, and the Highest fat be ihe Loh on pce hick Downs
Norbury park
Bench beyond the summit of the re:
Leith hill tower
Beech Trees on the gaauli wide of Handley oe
VOL. 1V. ak
Feet
300
466
292
320
8035
585
XXX. Notice concerning the Shropshire Witherite.
By ARTHUR AIKIN, Esq.
MEMBER OF THE GEOLOGICAL SOCIETY,
AND SECRETARY TO THE SOCIETY FOR THE
ENCOURAGEMENT OF ARTS MANUFACTURES AND COMMERCE.
[Read 6th December, 1811. ]
Tue Witherite or native carbonate of barytes, still continues to be
one of the rarer productions of the mineral kingdom. The only
thoroughly ascertained locality of this substance, according to Pro-
fessor Jameson, (System of Mineralogy, I. 575,) is Anglesark in the
county of Lancaster, where it was first discovered by Mr. James
Watt. It is here found in veins traversing the independent coal
formation, and accompanied by blende, galena, calamine and heavy-
spar. To this locality however may be added, on the authority of
Klaproth, (Analytical Essays, I. 389,) a mine near Neuberg in Upper
Stiria, where this mineral occurs in a bed of spathose iron ore.
The mine at Anglesark is, I understand, abandoned : it may there-
fore be a matter of some interest to the members of the Geological
Society, to state that my researches during the last.summer in pur-
suance of my mineralogical survey of Shropshire, have made me
acquainted with a mine, within the bounds of that county, in which
witherite occurs very abundantly.
The most hilly district of Shropshire extends from the borders of
Montgomeryshire to the town of Church Stretton, having the broad
valley of the Severn for its northern boundary, and stretching as far
Mr. Arxin on Witherite found in Shropshire. 439
south as the parallel of Bishopscastle. The general elevation of this
tract above the Severn varies from 800 to above 1500 feet. It is
completely intersected by two strait and simple vallies, the direction
of which is about north-east and south-west, and several smaller
ones parallel to the larger descend from the interior towards the
north and south. The principal rock which presents itself is grey-
wakke-slate, in beds which run north by east and south by west,
rising at an angle of about 50° east by south. The colour of the
rock where it has not undergone decomposition, is bluish or greyish
black, probably from a mixture of carbon, for by exposure to the
air it passes to a pale yellowish-grey, with a few spots of oxide of
iron. Its cross fracture is dull, but its longitudinal fracture presents
numerous small spangles of mica. The upper beds, or rather the
superficial parts of many of the beds, are in the state of shale, that
is, they are shattery, soft, and more or less decomposed. No true
veins ever occur in this shale, and even veins of considerable size
and regularity in the compact part of the rock, terminate almost
immediately on coming in contact with the looser part.
It is in this compact greywakke-slate, and chiefly on the western
side of one of the highest hills called the Stiperstones, that the
principal lead mines of the county occur. Of these, that which is
called the Snailbach mine, is the most important for its metallic
produce, and is the only one in which witherite has hitherto been
found.
The mine consists of one principal vein, with several strings
proceeding from it. Its course is nearly east and west, descending
at a high angle to the south: its greatest depth is about 180 yards,
and there are no signs of its approaching to a termination: its
general thickness is 10 or 12 feet, but in one particular part amounts
to more than 30 feet. Cavities, or locks as the miners call them, are
3K 2
440 Mr. Aik1Nn on Witherite found in Shropshire.
frequently met with of all sizes, from that of a walnut to that ef a
small room: many of the lesser cavities are filled with petroleum,
the others are lined with crystals of heavy-spar, calcareous spar,
and quartz, having their bottoms or floors covered with aggregated
masses of the above crystals, with crystals and potatoe-shaped pieces
of galena, with carbonate of lead, and with a black powder
which is principally pulverulent galena. In some parts there is a
saalbande or sticking of grey clay an inch or two in thickness, and
here the vein is the least productive; in other parts the rock
is hardened by an infiltration of quartz, and these are uniformly
found to be the most productive. There is no regularity in the
arrangement of the contents of the vein, but generally the galena
occupies the sides, and the sparry veinstones the centre. Riders,
or ribs of rock inclosed within the vein occur, but not frequently.
The ore is for the most part foliated galena and striated galena,
called by the miners fot ore and steel ore: iron pyrites is the next
in quantity, and lastly blende, this latter being for the most part so
intimately mixed with the galena as to be scarcely visible. The
veinstones are calcareous spar, often approaching to schiefer spar,
and foliated heavy-spar (called here water spar, because from the
looseness of its aggregation most of the water drains through it
into the mine.) Quartz is more rarely met with ; and in the lower
part of the mine, where the vein is very thick and sparry, the
witherite is found in irregular masses, weighing from 40 lbs. to
2 or 3 cwt., imbedded in heavy spar. The name given to this
substance by the miners is yellow spar, not that this is its real
colour by day-light, but its transparency is so considerable that if a
lighted candle be placed behind a mass of it the whole will glow
-with a yellowish light, a circumstance by which the miners dis-
tinguisb it from heavy-spar; this latter from the looseness of its
Mr. AtKxin on Witherite found in Shropshire. 441
texture being in large masses quite opake. ‘The colour of the
witherite is white with the slightest possible, if any, tinge of yellow:
its fracture is broad striated approaching to strait-foliated: it is for
the most part massive. I have seen only a single specimen that
presented any indications of a regular crystalline form. In other
particulars it agrees with the usual descriptions of this substance.
The Anglesark witherite has been analysed by Klaproth, and
besides carbonate of barytes appears to contain above two per cent.
of carbonate of strontites, and a scarcely appreciable quantity of
oxide of copper. The Stirian witherite, on examination by the
same chemist, appears to be a pure carbonate of barytes. The
presence of carbonate of strontites being a circumstance of some
interest, I was induced to examine the Shropshire Witherite for the
purpose of ascertaining whether in this particular it agreed with
that from Lancashire.
For this purpose 200 grains were dissolved in muriatic acid, and
left behind 1.8 gr. of a white powder which was sulphate of barytes.
The muriatic solution being supersaturated with ammonia was
evaporated to dryness and ignited till the muriate of ammonia was
driven off: the residue was redissolved in water, but left behind
1.5 gr. of a brown sediment, which on digestion with sulphuric
acid was separated into 1. gr. of silex insoluble in the acid,
and 0.5 gr. of alumine coloured by oxide of iron, soluble in the
acid, and which deposited crystals of alum on the addition of
sulphate of potash.
The purified muriatic solution was brought to the crystallizing
point, and the muriate of barytes which tell down was removed :
the mother-liquor was mixed with alcohol and heated, the fluid
(after standing a minute to clear) was poured off, and on cooling
deposited long needled crystals of muriate of strontites. Water
4492 Mr. Arxin on Witherite found in Shropshire.
was then added, the crystals were redissolved, and carbonate of
ammonia was poured in till it occasioned no further precipitate.
The carbonate of strontites thus obtained weighed on ignition
2,2 gr. and being redissolved in muriatic acid and mixed with
alcohol communicated to the flame of this last the red colour cha-
racteristic of strontites.
The muriate of barytes was in like manner decomposed at a
boiling heat by carbonate of ammonia, and the carbonate of barytes
thus obtained weighed, after edulcoration and ignition, 192.6 gr.
Hence 100 parts of this witherite contain
96.3. carbonate of barytes
1.1 ———— of strontites
0.9 sulphate of barytes
0.5 silex
0.25 alumine and oxide of iron
99.05
0.95 loss
XXXII. Extracts from the Minute Book of the Geological Society.
1810, February 2. .
AN Extract of a letter from Dr. Macdonell, of Belfast, to Mr.
Horner, was read, in which an account is given of a stratum of sub-
marine peat and timber in Belfast Lough, situated under the level
of ordinary tides, but generally left bare at ebb tides. Nuts are
numerous in it, both on the east and west sides of the harbour.
On the east side, where calcareous rocks exist, the nuts are filled
with calcareous spar, but on the west side, where the rocks are
schistose, they are empty. Some of them are perfectly filled,
others only partially so, yet the shell appears quite entire, and un-
changed by any petrifactive process, although when put into acids
some effervescence takes place. Dr. Hutton alledges that no infil-
tration can happen in circumstances similar to that in which these
nuts are placed, for they are immersed in a bed of peat four or five
feet thick, and this covered by a deposit of sand, shells, and blue
clay, and the whole kept moist and all evaporation prevented by
being covered three-fourths of the day by the tide.
1811, January 18.
An extract of a letter from Dr. MacDonnell, of Belfast, to Mr.
Horner, was read, giving an account of some granite veins in slate,
in the Mourne mountains.
In some part of these mountains, which are situated at the south-
ern extremity of the county of Down, grey granite forms the sum-
444 Extracts from the Minute Book of the Geological Society.
mit of the mountain, and primitive slate the sides. The contacts
are as sharp as possible, without the least of one rock graduating
into the other, and in all cases the granite is continued from the
great mass in veins through the slate, but never the contrary.*
Masses of slate often occur, like islands floating in, and surrounded
by the granite of the veins. Mr. Playfair, who was with Dr.
Mac Donnell, remarked that the schist, which lies upon and near
the granite, has a much greater number of fissures than that which
isa mile distant. The granite veins generally terminate in fine
threads.
1811, November 1.
A letter from George Cumberland, Esq. of Bristol, was read,
giving an account of a trap rock that had been discovered at Mickle-
wood, in Gloucestershire. It occurs to the east of the road going
from Bristol, within two miles of Frampton, on an estate belonging
to Lord Berkeley, and is known by the name of the O/d Rock.
The mass rises perpendicularly to the height of about 30 feet,
is less than 300 yards wide, and extends in the other direction
about a quarter of a mile. The same rock is found again to the
north-east of the first mentioned place, dipping to the east beneath
the surface.
The Micklewood rock has an amygdaloidal character, contain-
ing plain or striped chalcedonies, and numerous fungiform or ir-
regularly cylindrical masses, composed of iron spar. Those masses
are often found two feet in length; the chalcedonies vary from
one to twenty inches in diameter, and are nearly all of the same
shape, convex above, and concave beneath,
* pi, 28, Fig. 1.
Extracts from the Minute Book of the Geological Soctety. 445
1811, November 1.
An extract of a letter from Dr. Murray, of Harrogate, to Mr.
Sowerby, was read, mentioning that sulphate of strontian had been
found in limestone on the banks of the Nidd, near Knaresborough.
1812, March 6.
A notice by Arthur Aikin, Esq. was read, on a green waxy sub-
stance found in the alluvial soil near Stockport, in Cheshire.
In 1811 a specimen from the abovementioned place was commu-
nicated to the Society by Dr. Henry. On a chemical examination
Mr. Pepys found it to be a combination of resin and oil mixed with
a quantity of brown quartzy sand. Its colour was bluish green,
and was at first supposed to be occasioned by copper, but no me-
tallic matter except iron was discovered in it. From its compo-
sition, and the small depth at which it was found, it was not sup-
posed to be a natural product, but Mr. Aikin is inclined to doubt
this conclusion, having met with, in the Dictionnaire d’Histoire
Naturelle, under the article Sabliere, an account by M. Patrin,
of the discovery of a similar substance at the foot of the hill of
Menil Montant, near Paris. It there occurs in sand, accompanied
by fresh water shells.
1812, June 19.
A notice by C. Mackintosh, Esq. on the aluminous strata at
Campsie was read.
The coal formation which the Scottish aluminous strata accom-
pany, may perhaps be traced and identi ed in four distinct points
of this particular district of Scotland, namely, Campsie in Stirling-
shire, Kilpatrick in Dumbartonshire, and Hurlet and Houston, in
VOL. Iv. +
446 Extracts from the Minute Book of the Geological Society.
Renfrewshire. The strata of the four places vary indeed in thick-
ness, but their position and alternation may be considered the same.
A sketch of the Campsie strata is subjoined, as descriptive of the
whole.
After passing through the soil and one foot of limestone, alternating strata
of Bituminous Schistus and ironstone occur, till we arrive at the immediate
vicinity of the aluminous materials ; which are,
Limestone : sal Sa : ; ; ; : ~ ., & feet
Aluminous schistus, which consists of (what the miners call)
the gentle slate, and the diamond slate A : 2
Coal, of the caking quality of the Newcastle, which contains
the slaty and the nodular pyrites ° ;
Fire Clay of excellent quality : : A : . 1
The coal has been extensively excavated for a long series of
years, from mines of which the temperature is seldom under 60°
Fahr. frequently as high as 80°, in places excluded from any direct
current of air. The circulation of this warm air has ripened the
hard slate into various qualities, and these contain proportions of
alum and copperas, which vary according to the time of their expo-
sure, the recent slates abounding in copperas, those longer exposed,
in aluminous matter.
1815, April 7.
A notice was communicated by Leonard Horner, Esq. respecting
the rocks of the Isle of Tino, in the Archipelago.
The highest part of Tino is one long ridge of limestone, which
affords excellent marble, that is sent for grave-stones to Smyrna
and Constantinople. In the garden of an Italian convent there is a
beautiful vein of asbestos running through serpentine, which passes
into a kind of verde antique. It is stratified and dips westward
Extracts from the Minute Book of the Geological Society. 447
about 65°. Here are many rich veins of lead, which generally
occur in large veins of quartz in sandstone. The schistus of this
island, on the side opposite to Andros, is well calculated for slates ;
that opposite Miconi is very micaceous,
1815, November 3.
Dr. Traill presented to the Society some magnetic iron sand,
mixed with much iserine, accompanied with a letter, of which the
following is an extract.
“I send you a bag filled with magnetic iron sand, mixed with
much iserine, which I discovered more than two years ago in the
hundred of Wirral, in Cheshire. It occurs on the shores of the
Mersey, opposite to Liverpool, at Seacome Ferry. After heavy
rains it oozes out of a deep bank of clay ; but I strongly suspect
that its matrix is the coarse reddish brown sandstone of the country,
which, near Seacome, contains many quartzy nodules.”
In a subsequent [etter (dated 26th October, 1816) Dr. Traill
says, “ After the heavy rains of this summer, I have traced the
magnetic iron sand and iserine for several miles along the coast.
They are washed out of a bed of cohering sand that lies below the
clay, and may be considered as entering largely into the Geological
composition of that part of Cheshire.”
1815, December 15.
A Letter from the Rev. Archdeacon Barnes was read, dated
Bombay, March 31, 1815. In this letter Mr. Barnes communi-
cates, on the authority of Mr. Copeland, Assistant Surgeon to the
European force in the Guzerat, some particulars relative to the car-
nelians of Cambay.
These are all procured from the neighbourhood of Broach, by
3L2
448 Extracts from the Minute Book of the Geologieal Society.
sinking pits during the dry season in the channels of torrents. The
nodules which are thus found lie intermixed with other rolled peb-
bles, and weigh from a few ounces to two or three pounds. Their
colour when recent is blackish olive passing into grey. ‘The prepa-
ration which they undergo is, first, exposure to the sun for several
weeks, and then calcination. ‘This latter process is performed by
packing the stones in earthen pots, and covering them with a layer
five or six inches thick of dried goat’s dung; fire is then applied to
the mass, and in twelve hours time the pots are sufficiently cool to
be removed. The stones which they contain are now examined,
and are found to be some of them red, others pink, and others
nearly colourless, the difference in their respective tints depending
in part on the original quantity of colouring matter, and in part,
perhaps, in the difference in the heat to which they have been
exposed.
1816, January 5.
A communication from J. Taylor, Esq. Member of the Geological
Society, on some remarkable appearances in coak, was read.
The coak in question is produced from two varieties of Newcastle
coal, known in the market by the name of Tanfield moor and
Pontop. The coal is charred in an oven of brickwork, of very
simple construction, each charge being sufficient to cover the floor
to the thickness of 18 or 20 inches. The combustion begins at the
surface and proceeds gradually downwards. When all the bitumi-
nous matter has been driven off, the mouth of the oven is opened
for the purpose of drawing the charge, at which period the coak
presents the appearance of a glowing pavement rifted into perpen
dicular columnar masses, the bases of which rest on the floor of the
oven. Adherent to the sides of these rifts are occasionally found
Extracts from the Minute Book of the Geological Society. 449
concretions of a rather flat and small botryoidal external figure of
an iron black colour, and highly metallic lustre, resembling grey
manganese, or black hematitic iron ore.
Intermixed with these are small arborescent tufts, about a quarter
of an inch in length, adherent by their base to the mass of coak,
each branch of which, when examined by the microscope, appears
composed of minute botryoidal shoots.
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A LIST OF DONATIONS
TO THE LIBRARY,
TO THE
COLLECTION OF MAPS, PLANS, SECTIONS,
AND MODELS ;
AND TO THE
CABINET OF MINERALS,
BELONGING TO THE
GEOLOGICAL SOCIETY,
From the Close of the Ninth Session in June, 1816,
to the Close of the Tenth Session in June, 1817.
TOGETHER WITH THE DATES AT WHICH THEY WERE RESPECTIVELY MADE,
AND THE
NAMES OF THE DONORS.
I. Donations to the Library.
1816, BOOKS,
June 1. A Description of the principal picturesque Beau-
ties, Antiquities, and Geological Phaenomena,
of the Isle of Wight, by Sir H.C. Englefield, Bart.
with additional Observations on the Strata of
the Island, and their continuation in the adja-
cent parts of Dorsetshire; by Thomas Webster,
Esq.
Aug. 2. Histoire Naturelle de diverses substances mine-
rales siliceuses passécs a Vetat de Pechsteins,
ou pierres de poix, par M, Faujas deSaint Fond.
Paris, 1816, 4t°
Annals of Philosophy for August, 1816, by Dr.
Thomson.
Sept. 1. Annals of Philosophy for September, 1816, by
Dr. Thomson.
Journal de Physique for March, April, May,
and June, 1816.
Oct. 25. Annals of Philosophy for October and November,
by Dr. Thomson
DONORS.
Sir H. C. Englefield, Bart.
Memb. G. Soc,
The Author.
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14.
15:
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28.
29.
Dee. 5,
LIST OF DONATIONS.
BOOKS,
. Notices sur des Plantes Fossiles, renfermées dans
un Schiste marneux des environs de Chaumerac
et de Roche-Sauve, department de l’ Ardeéche
par M. Faujas de Saint Fond.
. Nos. 10 to 25 of the Mineral Conchology, of
Great Britain, by James Sowerby, Esq. Memb.
$
. Two Extracts from the Bibliotheque Britannique
De la matiére premiere des Laves, & Refuta-
tion de l’Hypotheése d’un Auteur anonyme sur
Ja formation des Vallées, by J. André de Luc.
Essai sur le Departement de PAude, adressé au
Ministre de V’Interieur, par C. I. Barante,
Prefet de Genéve, _ 1 vol. 8ve
Mineralogie Sicilienne, docimastique et metallur-
gique, par l Auteur de la Lythologie Sicilienne,
Turin, 1780. 1 vol. Sv°
Voyage Mineralogique fait en Hongrie et en
Transilvanie, par M. de Born. Paris, 1790.
1 vol. 8°
A Treatise on the external, chemical, and physi-
cal characters of Minerals, by R. Jameson,
Hon. Member of the Geological Society.
Edin. 1816. 1 vol. 8y°
Accompanied by a set of illustrative Models.
Mineralogie Homerique, ou essai sur les Mine-
raux dont il est fait mention dans les Poémes
d’Homeré par A. L. Millin, Membre de ’Instiut
royal de France, &c.
Paris, 1816, 2d edit. 1 vol. 8y°
Theophrastus’s History of Stones, with an English
Version and Notes, 2d edit. by Sir John Hill.
Lond. 1774. 1 vol. 8v°
A General Account of the Rivers of note in
Great Britain, by Henry Skrine, Esq. LL.B.
Outlines of Mineralogy and Geology.
An Elementary Introduction to the knowledge
of Mineralogy. By William Phillips, M.G.S.
Annals of Philosophy, for December, 1816. By
Dr. Thomson.
Annals of Philosophy by Dr. Thomson, for July.
Considerations sur les montagnes volcaniques,
par M. Collini, Directeur du Cabinet d’ Histoire
Naturelle, de 8.A.S.E. Palatine et de Baviere,
Manheim, 1781, 1 vol. 4t°
Mineralogisch geographische und andere ver-
mischte Rachrichten yon den Ultaischen Ge-
birgen Russisch Ranserlichen Untheils von
H. ’M. Renovans. Reval. 1788, 1 vol. 4t°
Physikalisch-Metallurgische Abhandlangen uber
die Gebirge und Bergwerke in Ungaro von
Johann Jakop Ferber, Prof. ia Mitan,
Berlin, und Stettin, 1780, 1 vol. 8°
DONORS.
The Author.
TheAuthor.
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G. B. Greenough, Esq.
Memb. G. Soc.
N. J. Larkin, Esq.
Memb. G. Soc.
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Sec. G. Soc.
The Author.
The Editor.
G. B. Greenough, Esq.
Memb. G. Soc.
LIST OF DONATIONS.
1816. BOOKS.
Dec.: 5. Voyage Mineralogique Philosophique et Histo-
rique en Toscane, par le Docteur Jean Targi-
oni Tozetti. Paris, 1792, 2 vols. 8v°
Journal de Physique for July and Aug. 1816.
6. Tableau Synoptique d’Oreognosie, ou connois-
sance des montagnes ou roches donné par
M. Tondi, dans son dernier cours particulier
en 1811.
Memoria Mineralogica sulla montagna e sui con-
torni di S. Gottardo di Ermenegildo Pini.
Bibliotheca Italiana ossia Giornale di Lettera-
tura, Scienze ed arti compilato de Una Societa
di Litterati, tomo. 1. Milano, 1816.
17. Journal of Science and the Arts, edited at the
Royal Institution of Great Britain, Nos. 1,
2, & 3.
18. Der Granit des Riesengebirges und di ihn umge-
benden Gebirgs-Familien, eine geognostische
Skizze von Karl von Raumer Bergrath und
Professor in Breslau.
Breislak mineralogische Reise durch anen Theil
des Kirchenstaats.
Journal de Physique for September, 1816.
Handbuch zur Chemischen Analyse der Mineral
Corper von W. U. Lampadius, Professor der
chimie und des huttenwesens an der Freyber-
gen Bergacademie.
20. Report on the Tavistock Canal.
Description of Greenland, by the Chevalier
Charles Louis Giesecké.
24, Catalogue des 4 Collections de M. le Marquis
de Drée.
31. Annals of Philosophy for January 1817, by Dr.
Thomson,
Journal of Science and the Arts, edited at the
Royal Institution of Great Britain. No. 4,
1817.
Jan, 1. Meterological Table for 1816, extracted from the
Register kept at Kinfauns Castle, N. Britain.
27. Memoire sur la possibilité de faire vivre des mol-
lusques fluviatiles dans les eaux salées, et des
mollusques marins dans les eaux douces, con-
siderée sous le rapport de la Geologie. Par
F. S$. Beudant.
La Siderotechnie, ou Vart de traiter les Minerais
de fer pour en obtenir de la fonte du fer ou de
Yacier, par J. H. Hassenfratz, Inspecteur
Divisionaire au Corps Imperial des Mines.
_ 4vols. 41°
Transactions of the Linncan Society of London.
vols. 9, 10, & 11.
VOL. Iv. 3M
AD53
DONORS.
G. B. Greenough, Esq.
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Robert Ferguson, Esq.
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The Author.
The Author.
The Editors.
The Royal Institution of
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G. B. Greenough, Esq.
Memb. G. Soc.
Robert Ferguson, Esq.
Memb. G. Soc.
Alexander Henderson, M.D.
Memb. G. Soc.
John Taylor, Esq.
Memb. G. Soc.
Henry Heuland, Esq.
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M. le Marquis de Drée.
The Editor.
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Pres. G, Soc.
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454 LIST OF DONATIONS.
1817. BOOKS.
Jan. 31. Annals of Philosophy for February, 1817, by
Dr. Thomson.
Feb. 7. Journal de Physique for Oct. 1816.
Natural History of Fossils, by Emanuel Mendes
da Costa. Lond. 1757, 4t°®
Sciagraphia Lithologica curiosa, seu lapidum
figuratorum nomenclator, a Joh, Jac. Scheuch-
zero, M.D. Math. Prof. Tigurino, &c. Auctus
& Illustratus a Jac. Theod. Klein.
Gedani, 1740, 4t°
A Delineation of the Strata of Derbyshire, de-
signed from a Tablet composed of the Specimens
of each stratum, with an explanatory account,
by White Watson, F.L.S Sheffield, 1811, 4t°
Journal de Physique for Nov. & Dec. 1816. -
31. Annals of Philosophy for March, 1817, by Dr.
Thomson.
March 19. Outlines of Geology; being the Substance of a
Course of Lectures delivered in the Theatre of
the Royal Institution in the year 1816, by
W. T. Brande, Esq. Memb. G.S.
Observations on an astringent vegetable sub-
stance from China, by W.T. Brande, Esq.
Memb. G.S.
Bersuch einer Unleitung zur Geologischen
Renntnik der Mineralien von D. H. F. Lint.
Das Fichtelgebirge nach vielen Reisen auf dem
selben beschrieben von J. Th. B. Helfrecht.
2 vols.
Mineralogische berg-und huttenmannische Rei-
senbemerkungen vorzuglich in Hessen, Thu-
ringen‘am Rheine und im Seyn-Altenkirchner
Gebiethe gesammelt von Dr. Johann Ludwig
Jordan.
Histoire Naturelle de la Suisse dans l’ancien
monde, traduite de Allemand de Mr. A. S.
Grouner.
Gedanken uber Die Bildung des Basalts und die
vormahlige Beschafienheit der Gebirge in
Deutschland, von A. F. von Veltheim.
Bersuch einer mineralogischen Beschreibung des
Uralischen Erzgebirges von Bened, Fr. Joh.
Hermann. 2 vols.
Johann Gottlieb Kern vom Schnectensteine oder
dem Sachsischen Topasfelsen von Ignatz edlen
von Born.
Considerations generales sur les vestiges fossiles
vegetaux du sol des environs de Paris, par
M. Hericart de Thury.
30. Annals of Philosophy for April, 1817, by Dr.
Thomson.
DONORS.
The Editor.
Robert Ferguson, Esq.
Memb. G. Soc.
Dr. Wright of Litchfield.
Robert Ferguson, Esq.
Memb. G. Soc.
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_ The Editor. ‘
1817.
LIST OF DONATIONS. 455
BOOKS.
March 30 Journal of Science and the Arts, edited at the
May 2.
31.
1816.
Royal Institution of Great Britain, No, 5.
Le Regne Animal distribué d’apres son organi~
zation pour servir de base a |’Histoire Natu-
relle des Animaux et d’Introduction a ’ Ana-
tomie comparée par M.leCh. Cuvier, Conseiller
d’ Etat ordinaire, Secretaire perpetuel de ? Aca-~
demie des Sciences de l’Institut Royal, &c.
Paris, 1817, 4 vols. 8v°
Histoire Naturelle des Animaux sans vertébres,
par M. le Chevalier de Lamarck, Membre de
VInstitut Royal de France, &c.
Paris, 1815, 3 vols. 8v°
Memoire sur Jes Fossiles des environs de Paris,
par Lamarck, 4t°
Dictionaire Allemande - Francais contenant les
termes propres a l’exploitation des Mines a la
Metalurgie & a la Mineralogie, par J. B.
Beurard, Paris, 1809, 8v°
Elementary Treatise on Mineralogy and Geology,
by Parker Cleaveland, Prof. of Mathm. and
Nat. Phil. &c. in Bowden College.
Boston, 1816, 8v°
Annals of Philosophy for May, 1817, by Dr.
Thomson.
Memoire sur le vases murrhins qu’on apportaient
jadis en Egypte, et sur ceux quis’y fabriquaient,
par M. de Roziere.
Description Mineralogique de la valée de Qosseyr,
par M. de Roziere.
De l’Ibis Egyptien, par M. de Roziere,
De la Geographie comparée et de l’ancien etat
des cotes de la mer rouge, par M. de Roziere.
An Account of the Life and Writings of Baron
Guyton de Morveau, F.R.S. Member of the
Institute of France, &c. by A. B. Granville,
M.D. &c.
Journal de Physique for January, 1817.
Annals of Philosophy for June, 1817, by Dr.
Thomson.
DONORS,
The Royal Institution of
Great Britain.
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Sec. G, Soc.
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The Author,
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Il. Donations to the Collections of Maps, Sections, &c.
mAps, &c.
Sept. 24. Engraving of Fossil Bones in the Museo Valsa-
machi.
Oct. 25. Ordnance Map of Dorsetshire.
Dec. 6.
Geological Map of the vicinity of Nice.
Proof of the Outline of the Ordnance Survey of
Dorsetshire
11. Ordnance Survey of Sussex.
3M 2
Le Conte Demetrius
Valsamachi.
Col. Mudge,
Hon. Memb. G. Soc.
Capt. Marryat, R.N.
Memb. G. Soc.
Col. Mudge,
Hon. Memb. G. Soc.
456
1816.
Dec. 11, Vue occidentale de la Fortresse de Konigstein
1817.
March 19 Five Drawings of Fossil Alcyonia.
May 2. Andrews Map of England and Wales, 1786,
1816.
July 20, Fossil wood from the Ferruginous Sand near
Aug.
Sept.
Oct.
Nov.
Dec.
1.
1,
25.
LIST OF DONATIONS.
MAPS, &c.
en Saxe.
Nordliche Ansicht des Schlesischen Riesenge-
birges.
III.
SPECIMENS.
Sandy, Bedfordshire.
Specimens of Flint from the Chalk at Guildford,
with a recent sponge resembling it in general
form.
Fossil Organic Remains from the Chalk.
Specimen of the Brunswick encrinus.
Specimens accompanying a Paper by Mr. Anstice.
Specimens from Guadaloupe.
Specimens of Simple Minerals.
. Fossil Bones from Walton and Fossils from
Sheppey.
. Specimens of Ammonites in Portland stone.
Chromat of Iron from America.
. Specimens from North America.
Specimens of Lyas and its Fossils from the cliffs
on the Severn.
Fossils of the Chalk.
Specimens of Simple Minerals.
Specimens and Organic Remains from the vicinity
of Nice.
Organic Remains from the Lyas near Charmouth.
. Specimens of Bath Oolite, from Farleigh Down,
near Bath.
. Organic Remains from the Tagus.
Specimens from Montreal, in North America,
collected by the Earl of Selkirk.
. Specimens of Pitchstone, Pearlstone, and Sulphat
of Strontian on Trap, from the Euganean hills.
. Specimens of Kimmeridge Coal Money.
Specimen of Fossil Pentacrinus.
. Specimens from ltaly, and from the Voleanic
district on the Rhine.
Specimens from Auvergne.
DONORS.
G. B. Greenough, Esq.
Memb. G. Soc,
Miss Benett.
Sir H. C. Englefield, Bart.
Memb. G. Soc.
Donations to the Cabinet of Minerals.
Rev. Mr. Gorham,
Fel. Queen’s Col. Camb,
C. Stokes, Esq.
Sec. Geol. Suciety.
Rey. William Conybeare, &
Rev. William Buckland.
Mr. Anstice.
Rev. Mr. Guilding,
Memb. G. Soc.
J. Mawe, Esq.
Henry Warburton, Esq,
V.P:'G, Soe
Joseph Gawen, Esq.
Henry Warburton, Esq.
V.P. Geol. Soc.
T. W. Webster, Esq.
Henry Warburton, Esq.
V.P. Geol. Soc.
Johann Rohatsch, M.D.
Capt. Marryat, R.N.
Memb. G. Soc.
Charles Stokes, Esq.
Sec. G. Soc.
Henry Warburton, Esq.
V.P. G. Soc.
James Sowerby, Fsq.
Memb. G. Soc.
John MacCulloch, M.D.
Pres. G. Soc.
G. B. Greenough, Esq.
Memb. G. Soc.
W. H. Wollaston, M.D.
Memb. G. Soc.
Sir H. C. Englefield, Bart.
Memb. G. Soc.
G. B. Greenough, Esq.
Memb. G. Soc.
Edmond W. Rundell, Esq.
Memb. G. Soc.
1816.
Dec. 6.
1817.
LIST OF DONATIONS.
SPECIMENS.
Four Specimens of Fossil Fish from Monte Bolca
Veronese.
Specimens of Simple Minerals.
Five series of Specimens from the Isles of Skye
and Rasay, of Gneiss, Siliceous Schist, Acti-
nolite, and Sandstone.
Jan. 1. Specimens of Curl Stone from Monmouthshire,
Specimens of Oolite from the Cotswold hills.
Specimen of Steatitical Limestone from Skye.
Specimen of Sulphat of Soda with Magnesia, from
Calatoyad in Arragon,
A series of Hypersthene Rock from Skye and
Ardnamurchan.
7. Specimens from Scotland.
Specimen of crystallized Tourmaline with Appa-
tite, from Devonshire.
16. Specimens of Simple Minerals.
17, Specimens collected in Syria by Mr, Buckingham.
Specimen of arsenical Cobalt and native Silver
from Wilsworthy.
31. Specimens of Arseniate of Copper.
Feb, 7. Specimens of Garnet from Fahlun, and Gadoli-
nite in the matrix from Ytterby in Sweden.
Specimens of the rock at the bottom of the fall
of Niagara.
Specimens of red and green Tourmaline from
New England.
Specimens from Scotland.
20. Fossil Organic Remains from Germany.
Specimens of Slate from Angers, and six Trilo-
bites from Grenaudiere.
Specimens of the rock in which the Cave and
Sculpture of Elephanta is formed.
Mar. 7. Specimens from Scotland.
Specimens from Torre del Greco of Substances
that have been altered by being buried under
the lava from the eruption of Vesuvius on the
15th June, 1794.
Specimens from the neighbourhood of Kremnitz
in Hungary, and Specimens from the country
between Vienna and Venice.
DONORS,
Capt. Marryat, R.N.
Memb. G. Soc.
John ‘Taylor, Esq.
Memb. G. Soc.
John MacCulloch, M.D.
Pres, G. Soc.
John Norris, Esq.
Memb. G. Soc.
David Ricardo, Esq.
Memb. G. Soc.
John MacCulloch, M.D.
Pres. G. Soc.
M. Leman,
For. Memb. G. Soc.
John MacCulloch, M.D.
Pres, G, Soc.
J. Mawe, Esq.
Sig. Chierici.
Mr. Babington.
G. B. Greenough, Esq.
Memb. G. Soc.
Charles Stokes, Esq.
Sec. G. Soc.
Wm. Macmichael, M.D.
Memb. G. Soc.
Sir Henry Englefield, Bart.
Memb. G. Soc.
A. Aikin, Esq.
Memb. G. Soc.
John MacCulloch, M.D.
Pres. G. Soc.
G. B. Greenough, Esq.
Memb. G. Soc.
The Rev. Wm. Buckland,
Memb. G. Soc. and
The Rev. Wm. Conybeare,
Memb. G. Soc.
Hon. H. G. Bennet,
V.P. G. Soe.
Dr. Wright of Litchfield.
John MacCulloch, M.D.
Memb. G. Soc.
Hon. H. G. Bennet,
V.P...G. Sec,
G. B. Greenough, Esq.
Memb. G. Soc.
458
1817.
Mar. 21.
April 18.
May 2.
11.
June 6.
20.
LIST OF DONATIONS.
SPECIMENS.
Specimens from Scotland.
Specimens of the Green Sand stratum from Box-
ham, one mile east of Warminster.
Slab of Serpentine and primitive Marble, from
near the town of Milford in the State of Con-
necticut, North America.
Casts from Bivalves from the sand at Chobham.
Specimens of Ferruginous Sandstone impregnated
with bitumen from Chilly Sussex.
Series of Specimens of Slate from Dunkeld, and
a series of Mica Slate from Perthshire.
Specimens of Grauwakke with impressions of
shells from Devonshire.
Specimens found on the Strathmore estate, Parish
of Eassie, Forfarshire.
Fossils from the Ferruginous Sand, Parham Park,
Sussex.
Specimens from the Isle of Man and Rasay.
Specimens from the Pitch Lake in Trinidad.
Specimens from Syria and Egypt.
Specimens of Arenaceo-calcareous Stalactite from
Delvine, Perthshire.
Recent Shells.
Specimens from the Alps.
Specimens from the Basin of Paris,
Specimens from the Basin of Paris.
Fossils from the Stonesfield Slate.
Fossils from the Stonesfield Slate.
Specimens from Devonshire,
Specimens of Pyrophysalite and other simple
Minerals from Sweden.
DONORS.
John MacCulloch, M.D.
Pres. G. Soc.
Miss Benett.
William Vaughan, Esq.
Memb. G. Soc.
Charles Stokes, Esq.
Sec. G. Soc.
G. B. Greenough, Esq.
Memb. G. Soc.
John MacCulloch, M.D.
Pres. G. Soc.
Rev. William Honey,
Memb. G. Soc.
John Adam, MD.
G. B. Greenough, Esq.
Mem. G. Soc.
John MacCulloch, M.D.
Pres. G. Soc.
Hon. H. G. Bennet,
V.P. G. Soc.
M. de Roziere.
John MacCulloch, M.D.
Pres. G. Soc.
Miss Benett.
Dr. Jurin, of Geneva,
Ashhurst Majendie, Esq.
Memb. G. Soc.
KE. W. Rundell, Esq.
Memb. G. Soc.
Henry Warburton, Esq.
VP. .G: Soci
Hon. H. G. Bennet,
V.P.1G. See.
Thomas Meade, Esq.
M. Swedenstierna.
INDEX.
Actinolite rock, mass of in gneiss, in the Island of Oransa
Adularia, found at Tintagel . ‘ : ; A
Agate pebbles, found in Sky . : : ‘ $ ;
————_—— found at Kinnoul, deseribed 4
—, difficulty of describing ths
manner of their formation :
—— of the Giant’s Causeway, the paciael plates He’
in a horizontal position . . :
—— decomposition of, in the seine of Litchfield
Arkin, Arruur, Esq. Notice of some peculiarities observed in
the gravel of Litchfield :
, Notice on Shropshike Witt Bete
, on a green waxy substance found near
es
Stockport F ; a 3 ‘
Alcyonia, found in the sandstone at CW holbiiiY Camp .
Aten, WitiiaM, F.R.S. Barometrical Measurements, by
Alluvium, of Northumberland and Durham described ‘ en
--, account of a remarkable deposit of, in Sky . .
Alumine, its use when combined with lime for mortar
Aluminous Strata, at Campsie, Mr. Macxinrosu, on the
Analcime, of a brick red colour, found in Sky 2 3 :
Anatase, on the primitive crystal of ‘ . .
Asbestus, found in Melmerby scar
Avanturine, a variety of quartz rock . é
Augite, found in grains imbedded in the basalt of Teesdale
Augit rock, a rock of the trap family so called
Baculites, found by Mr. Hony, near Maestricht 2 -
Barometrical Measurements, by Mr. Auuen and Mr. Woops
Barytes, Sulphate of, Mr. Paituies on the primitive crystal of
, on the cleavage of
Basalt occurs in the lead mine measures of Northumberland
sometimes a regular bed in them . ‘ ‘
460 INDEX.
PAGE
Rasalt in the lead mine measures of Northumberland agrees in
situation with the toadstone of Derbyshire ; . : 73
overlying masses of, occur in many parts of the lead mine
measures . . : : , . . TA—78
Basaltic dykes. See Dy wre
Basaiiic veins in the granite and schist of Catashan ‘ : 123
Beadnel Bay, dyke at, described ; , : ; 102
Belfast Lough, nuts filled with calcareous spar misfit in . 443
Bennet, The Hon. Henry Grey, on a whin dyke traversing lime-
stone in the county of Northumberland . , i 102
Bitumen, found in some varieties of the magnesian limestone
near Sunderland . . : ° . : 6
Bituminous Limestone, analysis of one, a Dr. Cuarke . d 430
Blakheath, account of plastic clay beds near ; ‘ - 288
Blende, note on the cleavage of . P } A ‘ i 257
Bog iron ore, found in the Cheviot hills ‘ i é 95
Boring, estimate of the expence attending at Roxburg or Reenat 10i
Breccia, occurrence of one of a ae ie date at Loch Ericht,
having a siliceous cement : , ; ; ; “ine | De
Brendon Hills, height of the ; : A3T
Bricut, Ricuarp, M.D. on the strata in fre evehbour hea of
Bristol é , . 193
Bristol, Dr. Bricur ie Mr. Cieeeaers, on spree strata in the
neighbourhood of : 193
, sections of the strata ets given by Dr. pe and
Mr. CumBeRLAND . gas . 197
, horizontal beds Bene on ne edges of the rata a aR:
in the neighbourhood of é ‘ a 202
Bucxianb, The Rev. W. Description of an sciidied fog of
rocks of slate and greenstone, in Cumberland and West-
moreland, on the east side of Appleby, between Melmerby
and Murton . , ; : apisinit f ‘ 105
—_—______————, Description of a series of specimens
from the plastic clay near Reading, Berks: with observa-~
tions on the formation to which those beds belong . : 277
, Description of the paramoudra, a sin-
gular fossil body found: in the chalk of the north of Ireland,
with some general observations upon flints in chalk, tend-
ing to illustrate the history of their formation ; 413
—_————.
INDEX.
Cader Idris, height of ; :
Calamine, found frequently in the venaieen near Bristol
Campsie, Mr. MacxintTosu on the aluminous strata, at
Carlisle, plain of, consists principally of red sandstone .
Carnelians, account of the manner in which they are procured
_ in Cambay 3
Chalcedony, vegetables in : , : ‘
Chalk Flints. See Flints.
Chert, lias changed into, in Sky . ‘ :
Cheviot Hills, composed of porphyry . : ;
, its junction with the lead mine measures not Pigibile
- , bog iron ore and hematite found in :
Chiorite, frequbtt in the trap of Kinnoul 5
-—, crystals of, in quartz : :
Chlorite Schist, with felspar and quartz, see composed at these
substances interlaminated together, passing out of gneiss,
at Sleat, in Sky. ; 4
Crarxe, Epwarp Danie, LL.D. ‘Analecis of one aitdsad soa
of a dark bituminous limestone, from the parish of White-
ford, in Flintshire, North Wales
Clay ironstone, formerly collected by the Carron Company on
Holy Island ;
found in the ahate oF the lead mine measures
sometimes forming septaria
Coak, Mr. Taylor on some appearances in .
Coal, estimate of the quantity annually raised in ‘he Naaet aa
berland coal-field , ' ms 24
found in most parts of the lead mine districts
quantity of, shipped at Newcastie and Sunderland
quantity shipped from Hartley and Blyth collieries
quantity imported into London : . ;
dug near Melmerby and Ousby . : .
in Sky, appearances of | : :
altered by contact with basaltic aie See Dykes,
Coal measures of Northumberland and Durham described
some of the lower beds of resemble the lead
$id
mine measures :
VOL: 1% 3N
462 INDEX.
PAGE
Coal Measures, variable thickness of the beds of the 12
—— consequent difficulty of giving a general section 13
— various beds composing the, particularly detailed | 15
dykes in the é : : ; oe 21
—_—___—__——— other irregularities in ie 29
sections of the ‘ : : ; 31
——— mineral springs occurring in 51
shattered strata of, accompanying the Site ind
greenstone rocks near Appleby : : : ‘ 106—112
Coal works section of, in the lead mine measures 69
Conglomerate, lying on the trap at Kinnoul : . 227
Conyzeare, Rev. J. J. Memoranda relative to the paeinritie
veins, &c. of St. Agnes in Cornwall Z . 401
Notice of fossil shells in the stite of
Tintagel : : . : 424
Copper, ores of, found in Nonthumbertind ‘ina paki 84
Coruisk, in Sky, rocks of, described : 183
Corundum, on the primitive crystal and cleavage 6F . : 254
Cotham stone, one of the beds of the lyas_—. : : ‘ 196
Cross courses, in the mine of Huel Peever, their extent z 142
of later formation than the metallic veins 148
effect of one on the killas through which it
passes é : : 154
Cross Fell, one of ihe sate mountains in inglind 58
Cruachan, Dr. Mac Cutuocu’s remarks on the mountain so called,
in Argyleshire J 117
, difference in the paren racks oF from dives of
Alan : « A “ A 5 134
CumsBerLAND, Grorce, Esq. Notes extracted ial his commu-
nications on the strata in the neighbourhood of Bristol 193
On the strata at Whorlbury Camp
in Somersetshire P : : 7 Z j , 216
Account of a trap rock at Micklewood 444
Cyanite, on the primitive crystal and cleavage of 253
Dinsdale sections at : H : : - 97
Diopside, on the primitive crystal ani Ben ape of : ° 252
INDEX. 465
PAGE
Dorking, height of hills near P : : ; : ; A37
Dover, height of cliffs near : : ‘ : i : 437
Dunkerry Beacon, height of : : : , ; A37
Durham and Northumberland. N. J. Wincu, Esq. on the
Geology of 1
Dyke of basalt in the peak field of Nolehnmieciand ad Pas
ham, described _.. : ; : : 21
effect of on the coal where in contact with it 21, 24, 25, 26, 27
——— mineral resembling adularia found in that at Coley Hill 21
horizontal section of that at Walker colliery : ‘ 22
——— at Coley hill described ‘ . ; ’ ; ° 21
at Walker colliery : . . . : : ‘ 22
—~— at Walbottle Dean . 3 , ; ; i , 23
—— at Tynemouth castle . ; : . . . ; 24
at Butterby ° ? ; ; ; ° . ‘ 24
—— Ninety fathom. ’ : ; : : . , 25
Birtley : : ; : : : ; . 27
—— Thistle pit : ' : : , : : > 28
—— Heworth ‘ ; : . . , ‘ 28
—— of basalt in the lead mine measures : ‘ : . 76
—— at Tynemouth Priory . : 96
—— traversing limestone in Na tinuibertid! Me balers
account of one : 102
—— the whin composing it ee ih that of other sneha 104
— — through slate at Caterpallet aa of felspar mixed
with talc ° . ; . : ; . ; 109
Elvan, the name given to porphyritic veins in Cornwall ; 401
—-—, a Cornish term applied to chlorite and quartz : 152
Encrini, found abundantly in the black rock of Bristol : 198
Epidote, forms a constituent part of the trap of Garsven in Sky 188
Exmoor, height of j é ; AST
Extracts, oe the Minute book ae the Geatoarcal sua : 443
Fetid limestone, found in botryoidal masses in the magnesian
limestone of Hartlepool : : ° : : - 9
3Nn'g
464 INDEX:
PAGE
Fire-damp, account of : : E 54
Flinis in Chalk, Mr. Bucxiann’s Ober ations on ae i of Al3
, Theory of their formation on organic remains A420
—_—— , formed in a different manner from the geodes
in trap ae , : 3 A s : A292
Flints, plated, veins of, in Me : f A17
Flinty slate, appearance of in the clay slates of Crean when
in contact with veins é : , c 118
occurs on the Western sare of Sky . : . 176
Fossil, remarkable one found at Whorlbury camp AW
Fossils, of the plastic clay formation a ON: Me 299, 296—300
———, of the Plymouth limestone, observed by Mr. Hennan Al10
Fossil Fish, found in the magnesian limestone near Sunderland 9
Fossil Shells, found in the slate of Tintagel ; , . AQ4
— of Snowdon : ‘ ; 4AQ5
Galena, found in strings in Whitley quarry near Cullercoats . 5
—, the only metallic ore found in the magnesian limestone
of Northumberland and Durham ‘ : 9
———, found in nodules of clay ironstone in the cate of ne
ca measures : 4 - ‘ 19
——-, filling a crevice by tie side Heh wieale vein . : 24
~—, found near Bristol ~~. : , , 200—203
Gitzy, W. H. M.D. On the magnesian ghee. and red marl
or Sandstone of the neighbourhood of Bristol . ' 210
Glen Gloy, traces of parallel roads in. : , 334
Glen Roy, Dr. Mac Curt ocH on the parallel es of : 4 314
—, detailed description of the parallel roads of - 317
—, their breadth : : E Bliy: 322
—, their elevation above the sea bad ee lochs 327
——-—-, causes which produced them, were equal and similar 328
—, connexions of with the adjoining glens ~ ; . 332
, form and structure of the parallel roads of SHH s 337
, its connexions with thesea__.. : 338
, statement and examination of the ue uSlgteRs that me
parallel roads of, are works of art, as roads for hunting 343
, statement of the three hypotheses which attribute the
formation of the parallel roads to the action of water. 349
INDEX. 465
PAGE
Glen Roy, examination of the first hypothesis—a deluge or large
torrent . . . , . ; 352
— seat bse cites remains of water
terraces : ; ‘ . 362
—_—_—_—_-—————- third ae eer ee tana
ing the valley ‘ : . : ; 367
—, difficulties attending the third unica . - 374
————, position of the Moupdeaics of the supposed lake 375—384
—, the third hypothesis the most probable : 374—380
—, the level of the sea ice to be marked by these
lines : . ; i ; 390
Glen Turit, traces of nasiillch ipads in, eee tee . ; “ 332
Glenwhelt, the highest land in England in the parallel from
Newcastle to Carlisle . 5 : 57
Gneiss, of peculiar character, occurs in the sreniotitiey of Sleat
in Sky ° : : . ° 159
—, transition between it amd Peace and Hudsons 161—165
Goniometer, common, not calculated to measure crystals with
perfect accuracy . . : ° 237
—, reflecting, measurement én crystals i oe ‘ 233—241
Granitic rocks, detached masses of, compose the hill of West
Down in Devonshire. : é ° : 147
Granite, found at Dufton Pike in spent 5 : ; 109
, Junction of, with the schist at Cruachan ‘ : 120
, the country near Cruachan appears to consist chiefly of 125
, its extent there 9 P ; ‘ 128
, crowns the summit of Kithill j in ‘Dediinshire , e 147
, deposit of upon the schist at Cligga point : : A402
Granite veins, penetrate the schist of Cruachan at its junction 120
, in slate in the Mourne Mountains : i " AA3
Gravel, of Litchfield, Mr. Arxin’s observations on ds : A26
Greenstone and Slate, group of rocks of, described : ; 105
Graywacké slate, found in the Cheviot hills’. : : 94
- series, transition between it and gneiss in Sky . 161
Grouan, a Cornish term applied to clay porphyry : 152
Hawtin de, beishiaf ance ee PO te, oe
466 INDEX.
Heliotrope, occurs in the trap of Kinnoul ‘ d
Helvellyn, height of . 5 ; ° : .
Hematite found in the Cheviot hills
Hennan, Rev. Ricwarp, Observations on the lienane of
Plymouth 2
Holy Island, clay ironstone Ferme collesied on, te die
Carron Company
Hony, the Rev. W. E. Géslopiedl Remarks on the Mics, al
Maestricht : 5 i
Hornbiende rock, found in che Cheviot hills ; . .
schist, alternates with gneiss at Sleat in Sky
Huel Peever, Mr. Wivu1aMs’s account of the veins of ‘ a
Hastings, height of hills near :
Hypersthene rock, rock of the trap faecal so ond lisd: . :
Infiltration, process of, by which veins are formed
Ingleborough, height of
Tron, ores of; found in Noveluintseniobau and Dehen
Iron pyrites, found abundantly in coal and shale; sold to the
manufacturers of green vitriol : d : .
Tron sand, magnetic, found by Dr. Trait in Cheshire.
Iron, specular, on the primitive crystal and cleavage of.
Iron work, one only now remaining in Northumberland
Iserine, found by Dr. Traruz in Cheshire ‘ ‘
Jasper, its resemblance in character to porphyry ‘ oe
Junction of granite and schist at Cruachan : : ,
- of trap and schist at Kinnoul . : : 3 7
Killas, traversed by beds of other rocks in Devonshire
——-, Dr. Mac Cuxtocu on certain colours in 5
——-, the principal rock from the borders of Dartmoor lect
the Tavy
-, extends to the coast, and joins the Plymouth sarees
——--, of Devonshire intersected by metallic veins :
-, altered in its texture by a cross course
{
INDEX. 467
PAGE
Kinnoul, Dr. Mac Cut.ocn’s Observations on the Hill of , 220
, composed chiefly of trap ; . ‘ ; ° 221
, trap conglomerate at q é B . : 227
, junction of trap and schist at. -. . ; 228
agates, difficulty of explaining their formation ‘ 226
Lakes of Scotland, accumulations of alluvium are gradually
filling them 5 ; : : . 381
Haumonite, found near Loch Rewores in Sky A J , 187
, alteration in its degree of hardness : ° : 188
Lead, quantity of, annually shipped at Newcastle and Stockton 82
, carbonate of, on the primitive crystal and cleavage of . 257
, sulphate of, on the primitive crystal and cleavage of 259
mine measures, of Northumberland and Durham described 57
, uniformity of in the southern part of
Northumberland . ; : . . ‘ . 58
, total thickness of eigaidiad ’ ; 58
, sections of the : ’ : , ‘ 59
, coal found in most parts of . ; ‘ ‘67
, sections of the collieries in. 2 . 69
» organic remains in the 3 ° ; 71
» metallic veins in z F : 4 77
- , minerals of described : 83
Lemmington, iron work at, the only one now in Niiihunihenbyd 67
Lewisham, account of the plastic clay beds near : «285
Lias, of Sky converted into chert . . , : : 176
—— occurs at Redland near Bristol : ' ‘ : 196
Limestone near Ord in Sky, contains flint or chert in Siacaaies : 171
and Coal measures, shattered beds of accompanying
the slate and greenstone rocks near Appleby ‘ 106—112
beds of the lead mine measures described z , 65
more regular thickness in than the shale or
sandstone : : : ’ : ‘ i é . 66
, bituminous. See Bituminous Limestone
, entrochal, insulated mass of at Keisley ~ $ 114
, in balls, singular stratum of, near Bristol : J 201
—— series of Sky described : : : . ° 166
A08 INDEX.
Linton, height of { ; f 7 d =
Litchfield, Mr. A1x1n’s AseeeOn on the gravel of ; ;
' Lodes. See Veins.
London, account of the plastic clay beds near i eg .
, on the formation of the marsh lands near a titor
clay, occurring at Shooter’s Hill : : . :
Lyas. See Lias.
Lydian stone, appearance of in the clay slate of Cruachan when
in contact with veins
Mac Cunxocs, Joun, M.D. F.L.S. President of the Geological
Society, Observations on the Mountain Cruachan in Ar-
gyleshire, with some remarks on the surrounding country
-——___—____ +____——. Corrections and additions to
the Sketch of the Mineralogy of Sky, published in the
Third Volume of the Transactions of the Geological Society
ee
Observations on the Hill of
Kinnoul in Perthshire . : ’ ; . z :
——__—___—__-——_—_—— Supplementary observations
on quartz rock, made in 1814. , .
——————— Further sedan 1816.
On the parallel roads of Glen
Roy 3 . : . : ‘ ‘ . : .
- — On a shifted vein occurring
in limestone A : ‘ : :
a Eniieeriaa of a Supalewint
tary plate to the paper on vegetable remains preserved
in chalcedony, printed in the Second Volume of the
Transactions of the Geological Society .
iets Paes On a peculiar cenesiicg Sy
the colouring matters in a schistose rock é i :
Mac Downett, Dr. notice of nuts filled with calcareous spar in
Belfast Lough : : ; .
— on veins of granite in ‘aie in the Nonrne
Mountains 3 ' h 7 s - F :
LB ad
156
220
264
273
314
392
398
399
443
A43
INDEX. A69
PAGE
Macxintosu, C, Esq. on the aluminous strata at Campsie ; AAS
Maestricht, Mr. Hony’s remarks on the Geology of the vicinity of 310
Magnesian Breccia, note on, by Henry Warsurton, Esa. i 205
——-—, its connection with the red marl, and oc-
currence near Bristol, and on the Mendip hills : 207
————-—., conjecture as to the former extent of the
bed of, near Bristol : ; é 207
limestone, of Northumberland and iirrbaen Noise 3
—_— ————__—, remarkable deposit of, on the coal measures
at Cullercoats in Northumberland 2 . : A
» flexible variety found near eitieriand 6
———_ ——___-——, near Sunderland sometimes contains bitumen 6
,; of Northumberland and Durham rests on
the coal measures ; P . 8
,no coal mine yet won by rane ihaagek it ibid.
, and red marl or sandstone of fhe neigh-
bourhood of Bristol, Dr. Gintzy on : ; ‘ : 210
, near Bristol, analysis of ‘ : 212—215
, bed of, conformable to the mountain
limestone, near Ross and near Bristol ‘4 ‘ : Z15
Magnet affected by the summit of Cruachan , : sisal
Manganese, found in small quantities in Sky é . : 189
, found near Bristo} : = . : ‘ 201
Marble, of good quality found in the Isle of Tino P q AAG
Marle-shell. See Shell-marle.
Marsh Lands, near London, notices on the formation of ‘ 302
Melmerby, description of a group of rocks of slate and green-
stone near to ‘ - b . i : : . 105
Mendip hills, height of the . ; ; 436
Micaceous schist of Sleat in Sky, does not compose he whole
promontory, as stated in the preceding volume ; ‘ 159
Micklewood, Mr. Cumsertanp’s account of a trap rock at . AAS
Minehead, height of North hill near . : . : A37
Mines of Devonshire, near Morwel Down, enumerated : L49
Mineral Springs occurring in the coal field described. ‘ 51
, —-——-— in the lead mine measures. : ‘ - 88
VOL. Iv. 30
A70 INDEX.
PAGE
Morwel Down, in Devonshire, description of the tunnel through 146
Mountain limestone, forms an elliptical basin in the neighbour-
hood of Bristol ‘ : Z : : : ; ‘ 210
, coal measures resting on it ‘ : Q11
Needlestone, foundin Sky : : 189
Northumberland, Mr. Brennet’s account of a ne aeheee in pf 102
Northumberland and Durham, N. J. vee Esa. on the
Geology of . 5 ‘ 1
Nuts, filled with calcareous tlie fobnd.; im Belfast Paeah ; AAS
Okehampton, height of , F : . . 437
Old red sandstone. See Red Seer tear, Old.
Olivine, found in grains imbedded in the basalt of Teesdale. 74
——— found in Sky . : ‘ . 189 —
Oolite, stratum of found in the Be ts ffacuone ede at
Hartlepool . . : : ‘ ‘ ih
Organic remains found in the Hare secrete ler a: : 10
found in the coal measures : , 19
a none marine, among those of the coal measures 20
—— in the lead mine measures ; f : Zl
—— in the limestone of Sky _. ‘ 169, 175, 176
Paralel Roads of Glen Roy, Dr. Mac Cuttocn onthe . ; 314
Paramoudra, description by Mr. Bucxtanp of the fossil so called 413
—-— its mineral History connected with that of many
_ spungiform bodies found in chalk . - ‘ ‘ A16
Pentowan. Mr. Smits on the stream works of : ; : A04
Pen-y gant, height of : : : q A35
Petroleum, found in the black rol of Beaks: : ‘ F 199
Pups, Witi1AM, Esq. Account of some attempts to ascertain
‘the angles of the Primitive Crystals of Quartz and the
Sulphate of Barytes p " 2933
—_—_——__—.—. On the iced ae by the eaore
ing Goniometer of certain primitive crystals; with obser-
vations on the methods of obtaining them by mechanical
division along the natural joints of crystals. : : 241
INDEX.
Plastic clay, Mr. Bucxianp on the beds of ’ ‘
—, account of the beds of near Reading
—_——— —, — — —— near London * ‘
—, ———_—_ on the coast of Sussex
— their connexion with those of France
Plumsted, account of the Plastic Clay beds near ;
Plymouth, Mr. Hennan’s observations on the limestone of
Porphyritic veins, of St. Agnes. Rev. J. J. Conyzrarn on
—-—— probably contemporaneous with
the schistose rocks which they traverse . é ,
appearance of the schist in con-
tact with them ; ; . GPa tat ‘
Porphyry of the Cheviot hills described i .
veins of, traversing the schist and granite of palates
— generally appear perpendicular
of Cruachan, its varieties described 4 : 5
— shews a regular series of transition from
porphyry to trap ° :
Potter’s clay, found sumvelliatelp below the ail over the eal
measures ; : : : : - : :
Quartz, beds of, interstratified with the marble limestone of Sky
Mr. Paruuirs on the primitive crystal of 4 :
—_—— — on the cleavage of ‘ : , ;
Quartz rock and schist series of Sky, described :
—_—__ alternates repeatedly with red sand-
stone : : ° . : ° 3 :
—, Dr. Mac Cunzoca’ssupplementary observations on
————, circumstances to prove that its origin is partly
mechanical SED 3
, avanturine a variety of ‘ ; i ¢ -
—, particulars of its occurrence in Sky ,
, alternations of, with red sandstone and greywacke
schist é ‘ . : : . : :
Quicksands, covering the Hay measures
302