Aa ne
“Panannnnnnnnnnnnn ANAARA SS
a
Re
A
siristimctiites Somes
a
q
i
.
q
FF
neenecne Niteanenn eat
nnnnrnat”
AY Dannls
ween a 3
Aron Wheantnanansian
‘tah
on
hk
q
;
i
Ss
i
Fi
AA
Nps a.
va
TEN
AS
i
AF
a
Rl
R
|
\
conn AMA baa
‘ale
nn
f p naan A
Anat AAMAS
wnoausarh
Pel
>> »
AAMARE
Pana
> D> >»
a5:
a
<=
Oc
mM
os)
>
Lu
Zz
i
=
HARVARD UNIVERSITY.
Minhs Gulez
meee A Awa amet
anne i “se
‘Ay AAAS BBARAAa. na. AAs AAAS
Aa ARONA ANY AAA AAA aNa na
aRAanr
Wal ARAARAR A
wal AAARAA Da ans
A NAN AAANATAA
ARAAAAAA nine
Nat AAMAS
D. WHITNEY,
Sturgis Hooper Professor
J
MUSEUM OF COMPARATIVE ZOOLOGY
WAatannnnnrnnnincen a
| Mw AuA yesh ear
AAAARA \ Al fa AANA aN x mle
NAA apileaes
ANS ARG
aegel AaPaac iA
ft We
| ‘ol han ml
“AA
a
1) a
van AAA AANA
RON
Wh sds Ms
eee
nnn mutt ‘Ag nAA
an AAR AA Nin'A
AA! \
MaaRaakh fe Ra / Ab
LIBRARY
AAA
RAR 7 NAR AAS
RA AA’ « ; ASS
NAD BAR RAL ;
Ai Aa. *z AAACK
ARAMA WBA aaa
eae nn AAATNAAANN
Yai a VARA WAAR BY
leat ' ALY rv
Aj rT tat | Mids, JAA AAR ARARA
PANNA My,
aah AAAAA MAN MAAAAAAy
Any
ne
I = - ~ - = anARA \A Pp
| ANY
een ee
fa
ee’
THE
GEOLOGICAL MAGAZINE.
VOL. IV.
JANUARY—DECEMBER, 1867.
THE
GEOLOGICAL MAGAZINE;
Monthly Journal of Geologn:
WITH WHICH IS INCORPORATED
Pee Geb) Only; © 7G Sine
NOS. XXXI. TO XLII.
EDITED BY
HENRY WOODWARD, F.G.8., F.Z.S.
HONORARY MEMBER OF THE GEOLOGICAL SOCIETIES OF GLASGOW AND NORWICH ,; CORRESPONDING
MEMBER OF THE NATURAL HISTORY SOCIETY OF MONTREAL.
PaO iooOkR JOHN MORRES, E.G:S., &e., &:
AND
ROBERT ETHERIDGE, F.BS.E., F.G.S., &e,
VOL. IV.
JANUARY—DECEMBER, 1867,
LONDON:
TRUBNER & Co., 60, PATERNOSTER ROW.
CH. DELEGRAVE er Cre, 78, RUE DES ECOLES, PARIS.
LEIPSIC: F. A. BROCKHAUS.
TURIN & FLORENCE: H, LOESCHER. NEW YORK: LEYPOLDT & HOLT.
€ 1867.
HERTFORD -
PRINTED BY SIEPHEN AUSTIN.
LIST OF PLATES.
PLATES
Section of about eight feet of the upper pat of Upbal tok. field Bf
Ilford . : Pe eee
¥ I. II. Sketches to illustrate Mr. A. B. Wynne’s paper on Denudation ‘3
well iVe Cochliodonts;, .. . Rs Oo,
» V. Acanthopholis hares Chalk Marl, TMalkesiony 65
~ VI. Cycadean Fruits from the Seaman Rocks . 101
~ VII. Lower Silurian Graptolites . : 113
e VILL. Sgualodon Wilkinsonii ; Aroideous cuit fron ane Stoves:
field Slate . Rede inc) Corks os) Gop iO.
~ IX. Cycadean stem from heiebion Bisel 199
~ X. The Terraces on the Fraser River 206
v XI. Graptolites from Dumfriesshire . ; 256
v XII. Glacial action near Llandudno ; New Trilobites fom North
Wales . : 290
VY XIII. Pholas-borings near Roxopar: ievonshire! : 295
V XIV. Syringothyris from North America and Belgium 311
vy XV. Banded and Brecciated Concretions . Aas 337
Y XVI. Recent and Carboniferous Chitonidee 340
v XVII. English and Canadian Paleozoic Insect-remains 388
v XVIII. Railway Geology from Exeter to Newton-Bushell . 390
» XIX. New species of Brachiopoda from ae 454
, XX. Rock Veins . 5 481
, XXL Gonocypoda Bemoer “8 H. Woodward . 529
og a Necrozius Bowerbankii, A. Milne Edwards 531
LIST OF WOODCUTS.
Section across the Eglwysegle Rocks, near Tan-y-Castell 12
Asaphus Corndensis, Ogygia scutatrix, Asaphus eee pee
peliaia -. . c ae lonmmelien
Section from Sieranaee Cutting to Hitchin Station : 38
Section from Milton, near Gravesend, to Ratley Hill Waedl 39
Section on the River Indus, near Sukkur Pass, Upper Scinde . 43
Fasnet Rock and Light-house, coast of Cork . . 89
Diagram to show the relative ages of the Boulder-clays in the Batons
Counties . : 98
Diagram-section of the Tees Valley . i Fos care - 100
Diagram of Head-plates of Cheirolepis . . . - - . 148, 149
Diagram to illustrate the Geology of South Bediondenire 154
Section of Nullaberg, in Wermland, Sweden , : 161
Faults in Drift-sand at Rochdale . 183
194
iv. List of Woodeuts.
Diagram of the Glacial Terraces at the Fork of the Yangma Valley .
Sand and Clay Pocket, about 180 feet in diameter, in Mountain
Limestone, near Longrake Mine, Halkin Mountain, Flintshire .
Sand and Clay pit, Bwlch Farm, near Nannerch, Flintshire . :
Supposed general arrangement of Pocket, containing sand and clay
in Mountain Limestone, Bwlch Farm, near Nannerch .
Clay Pocket, Pant-du, near Llanberris . .
Sand and Clay Pocket, Caldon Hill lame stone Qetae Weaver Hills
Section of Weaver Hills, North Staffordshire
White Clays, Sands, and Pebble-beds overlain by Glacial Till, Ripden
Pit, Weaver Hills
Section showing the general on agin a ‘the sort yr ine
Phosphate-bed, north-west of Llanfyllin . . :
Section of Strata at Cwmgwynnen Mine, north-east of ibllesnse FA
Diagrams of the north and south entrances to Kent’s Cavern .
Plan of the Coygan Cave near Laugharne, Carmarthenshire
Profile of Cliff, looking towards the mouth of Glen-car :
Land-slip at the Protestant’s Rocks, on the south side of lene car,
Sligo . :
Section at Ingleton
Section at Horton, in Ribblesdale
Section at Crummack . ;
Tarn Close Quarry in the Carpenierous ‘idinasione near iiverstons
Section of an Escarpment on the supposition that it is an old cliff
Rough outline of the form of part of the Chalk-ridge in the Isle of
Purbeck . A
Section showing the relation off the Chalk- cliff and the Chall-escarp
ment in the Isle of Wight : ie
New species of Mollusca from the Caribean seen Deyaatis
Cliff at Pen Morfa, Great Orme’s Head . :
Section of Cliff, about twenty yards from its soumranpsman x Ben
Morfa : 3
Section from Afon Eden 40 Blnene, are lay mathe one fom Dhslers Thy
Section of Tern Valley ;
Section across ube Ouse Valley at ‘Becnehenn :
MAP.
4 Map of the General Glaciation of Ireland. .
234
THE
GEOLOGICAL MAGAZINE.
TO OUR GEOLOGICAL FRIENDS AND THE SCIENTIFIC PUBLIC.
Three years and a half have passed since the GroLocgrcaL
Magazine took the field, and during that period it has justly
earned for itself the good-will and support of all those most warmly
interested in the progress of Geological Science, and has proved
the readiest and most frequent medium of intercommunication for
English and Foreign Geologists, its pages being always “open to
all comers.”
It commends itself strongly to Students and working Geologists,
whose inquiries will be answered direct, or inserted in the pages of
the Gzotoctcan Magazine, in the form of “ Notes and Queries,” for
which space will always be provided.
Our numerous correspondents are earnestly requested to make
their letters as concise as possible, so as to admit of the imsertion
of as much and varied information as the space at our disposal will
admit.
Our best thanks are due to our Geological friends, not only for
their support, but also for their contributions of valuable original
articles, of which we have had no lack.
We would remind our friends generally that the mere reading of
the GroLocicaL Macazine, although a very good and commendable
thing in itself, is not all we expect from them. Like the Poet
Close, we earnestly hope that each and every able-bodied Geologist
will “buy a copy of our little work” for themselves.
Annual Subscribers should send in their names and subscriptions
to Messrs. Triipner & Co., 60, Paternoster Row, London, E.C.
The Grotocican Macazine can always be obtained through all
Booksellers in town or country ; but if any difficulty or delay arises
through this method of procuring it the Publishers will always be
happy to send it direct per post.
Tun Eprror,
2 THE GEOLOGICAL MAGAZINE.
All Communications for the Grotocican Magazine should bo
addressed to the Editor, 142, St. Paul’s Road, Camden Square, N.W.
Books for Review, and Parcels from abroad, should be sent
addressed to the Editor, at 60, Paternoster Row, E.C.
Form for Subscribers to fill up and send to their Booksellers.
Pages Be bit
To
Be pleased to add my name to the List as a Subscriber
for one copy of Volume V. of Tut Grotocgican Magazine, to be
published monthly by Messrs. TrUBNER & Co., the First Part of
which will appear on January 1, 1868, price Highteenpence each
number.
Signature
Address
Notrcz.—The FourtH Votums of the Gzotocican Macazine,
for 1867, will be ready in a few days, bound in Cloth, price 20s.
Cloth Cases for Binding Vol. IV. may be had, price 1s. 6d.
Vols. I-IV. may be obtained of Messrs. Triibner and Co.,
uniformly bound in Green Cloth, Gilt.
) ishib~ 1888, che.
Vols Mi USGos slide:
Vol. III. 1866. 20s.
Vol. IV. 1867. 20s.
London: TRUBNER and CO., Paternoster Row.
THE
GEOLOGICAL MAGAZINE.
No. XXXI—JANUARY, 1867.
Oa=ves GaN Acie Aston ey Se
——
I.—On an Otp LaAKE-BASIN IN SHROPSHIRE.
By Miss Eyton.
HE district known as the Wealdmoors of Salop is an ancient
lake-basin about seven miles in length, by four in width. It
lies east of the Wrekin, from which the ground slopes gradually
down to it. On the §.E., the high ground of Lilleshall, and its
vicinity, rises more abruptly, and on the N.H. extremity it is
intersected by the river Tern, which probably formed the principal
outlet. The centre of the basin is filled with peat, containing
remains of oak and hazel trees, very much decayed, and matted
together by thick layers of fibrous roots, and in the lower part, by a
species of moss, of which the fibre is too fine for the Sphagnum, but
which it is impossible to identify, on account of its decayed condition.
This peat attains a thickness of about six feet. Some years ago, a
bronze celt of fine workmanship, and which is considered to have
been manufactured since the commencement of the iron age, was
found imbedded in it.
I have already said that the lower part of the basin, from
Crudgington to Bigwood quarry, a distance of about three-quarters
of a mile, is intersected by the river Tern. At Crudgington, on the
right-hand bank of the river, and at about one hundred yards
distance from it, is an extensive deposit of low level gravel, which
was opened by the Market Drayton Railway Company, but which,
after being disturbed to the depth of about ten feet, is now closed.
This bed contains three layers, thus,—fine gravel mixed with red sand,
- about 2ft.; larger pebbles, with yellowish sand, about 2ft. 6in., or
3ft.; pebbles and sand, with clay, depth unknown. This gravel is
composed of very mixed materials. Pebbles of granite, quartz, flint,
and greenstone, are numerous, as well as fragments of the neigh-
bouring Red Sandstone, and, occasionally, rolled lignite. A ovranite
boulder, several tons in weight, was quarried from Ge Uh “is not
likely that a small sluggish river like the Tern, even in its older
and more powerful days, could have brought together, all these
different materials ; but upon the hypothesis of a lake, receiving
supplies from various sources, and with its waters tending towards
Vou. Iv.—NO. XXXI. 1
2 Miss Eyton—Lake-basin in Shropsiure.
one principal outlet, the difficulty is explained. Probably, too, much
of this gravel is the remains of an older drift, re-sorted and arranged
by the river, since the lake period.
Passing onwards to Bigwood quarry, we find the low shallow
valley, through which the river flows, intersected by a bank of New
Red Sandstone. And here, I doubt not, was once a fine example of a
cliff, cut through by the river; but alas, the hand of the destroyer
has been at work, and the face of the cliff is completely quarried
away, for building stone, defacing every natural trace. Probably a
dam once existed between this point and Crudgington, composed of
drift, partially filling up the opening in the sandstone, which might
then have been much narrower. The river water being thus pounded
back upon the low land, helped to form the lake, and the bursting or
gradual wearing away of the dam, to drain it.
Leaving the river, and passing on the inside (that is the lake side)
of the bank, we are struck with its curved outline, forming a section
of a basin, such as we may often see in the high ground surrounding
a recent lake. Following the Market Drayton Railway, we find that
it here cuts through a bed of grey mud, such as might have been
deposited by a sheet of still water.
Long-lane brick-field is situated seven-eighths of a mile from the
river on its left bank, and about eighteen feet above its present level.
It consists of two layers, red clay, with numerous pebbles, Aft. ;
stiff bluish clay, with rootlets, 5ft. The upper of these layers is
composed of much the same materials as the lowest bed of Crud-
gington drift. Pebbles of flint and granite, both pink and grey, are
equally common, with the denuded Red Sandstone, and fragments of
Carboniferous limestone, from Lilleshall. I picked up one curious
specimen of the latter, containing stems of encrinites, standing up in
relief, the limestone having been weathered away between. The blue
clay, which I suppose to have formed the original lake bottom, (the
pebbly clay having been drifted over it,) contains numerous rootlets,
showing that the water must here have been shallow enough, to allow
of the growth of bog plants. Underlying the whole is a layer of
loose, coarse sand.
I should be inclined to assign a date to this lake about contem-
porary with the low level drifts. Since that period it must have
been gradually filling up, until the ground became firm enough to
afford a hold for the roots of forest trees. Then came a later period,
when, by the choking-up of the small streams which drained it,
probably occasioned by falling trees, it was re-converted into a
swamp, from which condition it appears to have been gradually
subsiding at the time of the compilation of Doomsday-book. The
local designations, often refer to this period, as Kinnersley, (Kin-
naird’s eye, or island,) Hyton, (Isle town,) &c. Lastly, the period
of artificial drainage, which took place within the last hundred
years, and has converted it into excellent pasturage, and, in places,
arable land.
Norr.—Two teeth, believed to be those of Hguus fossils, have been found in the
low-level drift on the margin of the Weald-moors.—C.E.
Geol Mag L667. VolLV FLL.
DeWilde lith M&N Hanhart op
TO ILLUSTRATE M2 AB WYNNES PAPER ON DENUDATION. &c
: Shit
eae: 5
Geol Mag. 1867 VouLV PUL.
shat ae
cate 1 ASE “ste ft ip earth
fast evel tilly gate,
PECAN? kahit
a hebhie
= ot “ Ade,
3 gabareet tel bes
res at
See
fy
ht» cps gh Wee
“=~ é cents sie
DeWilde Jith . M&N Hemhart imp
TO ILLUSTRATE MZAB WYNNES PAPER ON DENUDATION. &c.
Wynne—Denudation and its Causes. 3)
TI.—On DENUDATION WITH REFERENCE TO THE CONFIGURATION OF
THE GROUND.
By A. B. Wynn, F.G.S., &e.
‘ (PLATES I. anp II.)
ff NTRODUCTION.—The consideration of the subject of Denuda-
tion requires so extensive an acquaintance with Forms of the
Ground in a field large enough to embrace all countries, that general
conclusions must be advanced with more or less reserve, in pro-
portion to the extent of our research. ,'
What we know concerning the external features of other worlds
throws but little light upon the manner in which those of our earth
were formed. From astronomers we learn, indeed, of mountains and
valleys in the moon,’ of more peculiar forms than those commonly
occurring upon the earth; and differing from them in their manner
of arrangement; but we have here totally different conditions in the
supposed absence both of water and atmosphere, while the crater-
like aspect of the elevations renders them comparable to but one
kind of terrestrial mountains, and that the least connected with
denudation. We hear also of great mountains upon some of the
planets, those in Venus being supposed to have the enormous height
of twenty-two miles.” In this case an atmosphere is believed to exist,
but whether these mountains have a similarity to those of our satel-
lite, or bear signs of denudation like those of the earth, remains un-
certain.
On the earth, however, whether from difference of causes or
different developments of some similar agencies, the features, though
smaller, are yet of sufficient grandeur, and surrounded by mystery
enough to invest with considerable interest enquiries into the
methods of their production.
Denuding Agencies.—The various features which the land presents
are generally understood to have been produced by a comparatively
limited number of causes, sometimes simple in their action, but vast
in their results ; they are principally chemical changes, aqueous denu-
dation, and the action of volcanoes in heaping up mountains of a par-
ticular kind. Of these, if denudation, either suberial or marine, be
taken as the immediate and principal cause of the configuration of
the ground, a more remote but not less necessary agency is to be
attributed to forces of elevation and also of depression—having
brought different portions of the land within reach of erosive action.
Antiquity of these Agencies.—It would be going too far back to spe-
culate upon the probability or otherwise of our planet having ever
presented a smooth unbroken surface in every part; enough that at
incalculably remote periods land and water existed upon it; that in
the water silts, sands and gravels were deposited, and that, there-
fore, denudation was taking place upon the land to an extent, some
idea of which may be arrived at from the great thickness of aqueous
formations known to Geology at present.
1 Geology of the Moon.—Gron. MaG., Vol. iii., p. 141.
* Wm. Carter, M.B., Plurality of Worlds.—Quart. Jour. Science, p. 232.
4 Wynne—Denudation and its Causes.
Differences in features of the ground the result of structure —In
seeking to discover from the forms of the land, the history of
their production, we soon become aware that marked differences in
them are connected intimately with differences of geological struc-
ture, and that the shapes assumed have a stronger relation to such
internal circumstances, ‘than to the external agencies by which the
forms have been developed.
The denuding actions in these countries while belonging to either
of the kinds, suberial or marine, are complicated by including the
operations of ice. It is here manifestly less easy to observe how
much of the results are attributable to one kind of denudation or
another, than in countries where ice is not believed to have been one
of the agencies employed.
Notwithstanding this glaciation, it will be seen that the general
effect produced by denudation upon rocks which have common
structural peculiarities, such as horizontal stratification, etc., is nearly
identical even in widely-distant localities. To take a few illustra-
tions. The nearly flat-bedded and steep-sided hills of millstone grit,
near Manchester, the tabular limestone mountains in the north-west
of Ireland, the very similarly shaped mountains overlooking Cairo,
Suez, and the west coast of the Red Sea, or those forming the scarps
of the great Indian trappean table-lands, of which the Western and
Malwa Ghats are examples, show a general uniformity of aspect
resulting doubtless from their nearly horizontal bedding. Very
different from these are the hill-forms taken by contorted rocks
which are as widely similar in their irregularity if in nothing else,
while the familiar heavy outlines frequently given by denudation to
granitic hills is equally well marked.
Some of these example are taken from a glaciated region, others
are exposed to the influences of excessive periodic rains and heat, and
others still are situated in what has been called a rainless district ;
but all are instances of forms produced by denudation, and their rela-
tive similarity is but little affected by circumstances of climate.
The valleys excavated out of rocks are even more similar in
general characteristics than those hills which have a common geo-
logical structure; marked peculiarities being chiefly observed where
they may be attributed to peculiar actions, such as that of ice ;
although there are some valleys whose denudation presents unusual
singularity.!
Hence it may be assumed that there is a general tendency in rocks
to yield upon the large scale certain similar results under the action
of denuding forces.
Cliffs: Subcerial and Marine.—Marine denudation being known to
produce cliffs, these, when they occur inland, have been attributed to
the former action of the sea; and as it is admitted that most of the
land has been frequently beneath the ocean, many inland cliffs must
have stood within reach of its denuding influence. But lofty land
cliffs very frequently occur in mountain recesses without such bold
1 See Prof. Ramsay’s paper, on Lake Basins.—Quart. Journ. Geol. Soc. vol. xviii.
1862.
Wynne—Denudation and its Causes. i)
features along more exposed external portions of their neighbour-
hood, thus reversing the order of things so often observable upon
existing coasts.' See Plate II. Fig. 6 (Coomassig Cliff, 1100 feet
high, forming one side of a glen or coom, near Sneem, Co. Kerry,
Ireland).
With regard to the possibly subeerial origin of these cliffs, we
may remark, that, through the joints by which rocks are traversed,
water finds its way more or less vertically downwards, tending to
separate masses in this direction which—when deprived of support
by springs, streams, ice, or it may be in some cases even by sea
waves—naturally fall away, leaving vertical, or approximately ver-
tical, faces of rock behind.?
In limestone rocks this action may be specially well observed.
The illustration, Plate I. Fig. 4, represents one of many fissures be-
coming gradually enlarged along the brow of Benbulben mountain
in Sligo. At A, a smaller one is beginning to open, another has
separated a pinnacle of rock at B, and others have caused landslips
and vertical cliffs in many places about this locality. Even clay,
drift, or alluvial detritus contains joints or lines of division [see
Plate II. Fig. 8, Lines of dislocation or division in drift (sand, clay,
and gravel), at Goldengrove, Co. Tipperary, Ireland (see explanation
of Sheet 126, Mem. Geol. Surv. Ireland) |; and although it might be
supposed in such homogeneous materials rain channels would always
commence gradually, one has only to observe how frequently nullahs
at their sources issue from abrupt vertical banks, which sometimes
overhang, to see that rain not only acts upon the surface of the
ground, but also in some cases at considerable depths, to which it
finds its way in the manner above described.
Long lines of inland cliffs, forming terraces above one another,
are assumed to have been caused by successive actions of coast
denudation. Against this natural conclusion it would be diffi-
cult to argue, particularly in the case of countries otherwise known
to have been submerged, while the reasoning in favour is strength-
ened by parallelism of the lines to each other, and sometimes to the
plane of the horizon.
Nevertheless some long cliff terraces can be pointed out, like those
in the County of Sligo, on Benbulben mountain, (part of which is
seen sketched in Plate I. Fig. 5), presenting such an appearance as the
cliff-forming strata, being bent into an anticlinal curve, which is
followed instead of being: intersected by the line of cliffs, the contrary
to what might have been expected if their base had remained for a
long period at sea level.
Other peculiarities in limestone cliffs occur, among the Burren hills
in Clare, for instance, being equally well marked on all sides of
narrow valleys and around nearly circular hills, instead of presenting
stronger evidence of exposure to marine erosion on the exteriors of
the hill groups, or like many existing islands, at one side than another.
1 See Mr. Maw’s paper.—Gero. Maa,, No. 28.
2 Since the above was written a very similar observation has appeared in a paper
upon five types of Earth’s surface, in the United States, by Mr. Lesley.
6 Wynne—Denudation and its Causes.
These—together with the absence of continuous terraces on moun-
tains;' not formed of horizontal limestone, but lying between these
limestone districts, while it may fairly be supposed that all were sub-
merged at the same time,—are points tending to throw doubt upon the
marine origin of certain of these cliffs and terraces (the crags and fis-
sures of which abound in evidence to prove the powerful action of rain
water) : for it can hardly be supposed that the sea had power to form
cliff-lines only out of limestone or horizontal strata: the coast of the
intervening mountainous country formed of other rocks in various
positions, presenting some of the finest examples of sea cliffs along
this part of the Atlantic shore.
Isolated Pillars and Openings.—We may find instances of isolated
rocky pillars upon hills the very aspect of which suggests that the
stone is being gradually disintegrated by rain, (such as are repre-
sented in Figs. 1 and 2 Plate I),? and also along coast-lines where
they are as evidently the results of marine denudation (an example
being given in Fig. 3, Plate I).
In like localities natural openings may be sometimes found tun-
nelled through rocks, thus a vacant space allows the light to be seen
through the profile of one of the rugged rain-worn hills on the south
side of the Great Indian Peninsular Railway, at some distance from
the Lanowlee station in the Deccan; and another remarkable in-
stance occurs in the sea cliffs of Innishnabro, one of the Blasket
Islands, off the coast of Kerry, where the nearly vertically bedded
rocks are pierced by large openings one above the other (Plate IL,
Fig. 7).
' These examples will show, not so much that they are in both cases
evidence of marine action, as that either marine or suberial agencies
may under certain conditions produce similar forms.
Suberial Denudation of Limestone, etc.—Suberial denudation is
perhaps most plainly visible upon limestone rocks. At all events
its powerful influence upon them cannot be denied, whether observed
on cliffs or upon mountain slopes, in the peculiar rain channels with
which the rock is sometimes furrowed, in caves and subterranean river
‘courses, or where boulders of different kinds rest upon pedestals of
this rock, marking the depth to which surrounding portions of the
1 My friend, Mr. Kinahan, in his paper, ‘‘ Notes on some of the Drift in Ireland.”
— Royal Geol. Soc., Ireland, March 4, 1866—speaks of lines of cliff in the hills of Yar
Connaught. The cliffs alluded to are supposed to be of the disconnected kind (of
which that at Coomassig is given as an example): their marine origin not being
strongly suggested by their appearance, which certainly differs widely from that of
the continuous cliffs and terraces in either the Burren or Sligo districts. Their oc-
currence between certain sets of contour lines related to sea level may be as much a
matter of course or of accident as the result of marine action, unless it can be proved
that the whole country was elevated equally, or at the same rate, with reference to
the present horizon.
* Fig. 1.—From a trappean hill at Wassid near the foot of the Inclines by which
the Gt. Indian Peninsular Railway crosses the Western Ghats. Fig. 2.—Part of a
sketch from the elevated hill station of Matheran, between the Ghats Proper and
Bombay,—(Trap rock).
3 Fig. 3.—‘‘ The Old Man Rock” formed (as well ascan be recollected) of Purple
Grit. Mouth of Bulls Creek, South-side of Dingle Promontory, Ireland,
Wynne—Denudation and its Causes. 7
latter have been, comparatively recently, removed by the action of rain.
Still this atmospheric action is sometimes slighter upon limestone
than upon other rocks, as may be witnessed in ruins and old build-
ings, the masonry of which includes both limestone and sandstone.'
Trappean rocks frequently yield to this action more readily than
limestone; and even where silicious ones form large masses, local
prevalence of joints or alternations of strata may favour the denuding
power of the atmosphere.
Almost every rock fragment we pick up is found to be weathered,
and if we observe a mountain slope covered with bare shingle, the
result of subeerial action, we cannot doubt its power to carry on the
reduction of the fragments to their ultimate disintegration, or that
the vast quantities of alluvium thus produced and left upon lower
portions of the surface indicate but partially more extensive oper-
ations of this nature. The power of this agency to denude the land
being admitted, it follows that the excavation of valleys and forma-
‘tion of hills is only a matter of time.’
Coast Lines.—Although the sea coast has a certain relation to the
form of the land, it may be doubted whether it has any to show that
the surface of the latter has depended for its shape upon marine
denudation. ‘To remove such doubt it must be proved that all parts
of the existing surface have been successively acted upon by the
sea, and consequently that atmospheric influences have not since
materially altered its configuration ; but this is just the point in dis-
pute among the advocates of marine versus subeerial denudation, and
is certainly far from being proved.
Where deep valleys in a mountainous country open down to the
coast the sea enters them, but shows its denuding power most upon
the projecting lands between *—as might have been expected to occur
if the Valleys were produced by atmospheric agencies.
It is hardly necessary to allude to the evidence that the British
Isles at no distant geological period had a greater extent; while
around the South of Ireland the frequent occurrence of peat below
high water mark, even close to the bolder portions of the coast, serves
to show that some of the present sea-cliffs can hardly be entirely due
1 Numerous instances of the slow rate at which even limestone weathers, and there-
fore the enormous time required to produce results so evident, are familiar to most
observers. An inscribed slab of this rock in the interior face of the battlement of a
bridge, a couple of miles west of Athlone, although somewhat weathered, distinctly
showed in the year 1862, a date 100 years previous. Another limestone slab in a very
similar situation, facing the E.8.E., (The Liberty Stone), at Whitehall Bridge, near
Limerick, has an inscription, in raised characters, about one-eighth of an inch relieved.
The stone is but slightly weathered; the inscription, except in the last figure of the
date, is perfect, and the date is 1635. The preservation of glacial striz upon some
smooth surfaces of limestone, indicates a certain variability in amount of subzrial
action.
2The absence of references prevents further allusion here to the subject of valleys
which are lower than sea-level or those which being valleys of denudation discharge
water over rock barriers at a greater height than that of their interior parts. The
glacial origin of these will be found discussed in Professor Ramsay’s paper to the Geol.
Soc. Lond., Vol. xviii., p. 185.
3 See ‘On Watersheds, by Geo. Maw, F.G.S. ete.— Grou. Maa. Vol. III. No. 8,
p. 344.” and the outline of the S. W. Coast of Ireland.
8 Wynne—Denudation and its Causes.
to the action of recent marine erosion, unless it be admitted that the
seas at full tide can cut high cliffs out of hard rocks, and carry away
their débris without removing the soft peat which rests near their
base. ;
The part of the Irish Coast reaching from Waterford westward by
Mine Head to beyond Youghal Bay presents from the sea a line of
cliffs, with some intervals, where valleys open upon it. At the latter
place a quantity of peat may be observed between tides along the
strand; approaching at one spot within a few yards of the cliffs at
the mouth of the River Black-water.!
If the coast line here merely coincides with a portion of an older
one we should expect to find the old sea cliff following inland such
contour lines of the ground as would include the present one, but
although the ridges of that country frequently have steep sides, there is
no inland cliff continuous with that which edges the coast, nor is there
any reason to believe in the existence of one concealed by drift. Sup-
posing the coast line now to coincide entirely with an earlier one, the
land since the latter was produced must have presented a marked range
of cliffs, at some unknown distance from the sea, such as is not now
to be found at a greater altitude: in that neighbourhood, and must
subsequently have been depressed almost exactly to the same level
which it occupied before the peat was formed, and this without the
peat having been washed away during the depression or since it
occurred.
Otherwise, if we suppose the denudation of the valleys which open
upon this coast to have removed continuations of the older cliffs,
either inland or across their mouths, while the formation of the now
submarine yeat was taking place it follows that this denudation was
subeerial and unconnected with the sea, thus pointing to the
probability that the outlines of coasts are mainly the results of
depression, and that their configuration frequently depends upon
forms produced by subzerial denudation.”
1 The Valley of which is attributed to subserial denudation by Professor Jukes in
his able paper and interesting letter, See Quart. Journ. Geol. Soc. Lond., Vol. xviii.,
and GroLocicat Macazing, Vol. III., No. 5, p. 282.
With reference to the foot note to Mr. Kinahans paper. ‘On the Rock basin of
Lough Corrib,” Gzonocican Macazine, Vol. III., (Nov. 1866,) p. 495.—Supposing
the morass mentioned to be below high water mark, if a sand bar was thrown up by the
sea, the swamps behind it would naturally become a receptacle for peat independently
of the prior submergence of other localities. The argument requiring the former
existence of sand bars around so much of the bolder coasts of Ireland, hardly explains
their wholesale removal, while the supposition of depression would agree with the
similar occurrence on the East Coast of England. (See Mr. J. Geikie’s paper ‘On
the Forests and Peat Mosses of Scotland. Trans. Rl. Soc., Edin., Vol. xxiv). In the
example at Youghal a beach has been thrown up above and resting on the peat, which
is said to extend out beneath the bay at low water, and was observed when the tide
was very far out, or nearly at its lowest, beneath the sea as far as footing could be
obtained.
* Among many examples showing somewhat of the rate of erosion effected by the
sea, the case of the all but pre-historic Beehive Village of Fahan, in Kerry, may be
mentioned—a portion of which remains upon the verge of the sea cliffs at Slea Head:
or the tradition that Horse Island has been detached by the sea from Bolus Head in
the same county ; similar instances, save in the softer nature of the materials removed,
are the old Abbey and graveyard encroached upon by the sea at Ballinskelligs Bay,
Wynne—Denudation and its Causes. 9
Plains.—The observations of Professor Jukes,’ that the lesser eleva-
tions around a summit decline in altitude as they recede from it, so as
to suggest the former existence of a wide, gently-sloping plain, is in
uniformity with the fact that the superficial inclinations of ancient
ground subsequently became sea bottom, covered by unconformable
deposits, often sloping at very low angles ; although in many instances
there is reason to assume that peaks and valleys like those of our
own time were not absent. We can, however, form but a vague
idea as to the shape of the original surface of the ground before the
denudation of any particular locality began to take place, because
that surface has been removed, and so few land surfaces of any
period are known which have not suffered, more or less, from
denudation.
The origin of plains is perhaps the greatest difficulty in the
question of production of forms by denudation. We can conceive
of sea-cliffs being forced into existence by waves, or inland pre-
cipices being the result of slow atmospheric agencies ; of gaps being
cut in the land and portions isolated by marine action; and of deep
valleys being gradually eroded by ice or rain ; but the production of
large plains, irrespective of the kind or stratification of their rocks,
is not so easy to realise, perhaps because we do not absolutely see
them in process of formation.
Knowing that the sea continually eats away the land, we can
imagine that its action, being continued indefinitely upon land at
rest, would produce some sort of plain; but it is hard to conceive of
this horizontal action upon rock, insoluble in salt water, having no
limit ; while if the land were changing its position, slopes would be
more likely to result than either cliffs or plains.
Most plains are formed of ground sloping at various low angles (in
the case of alluvial flats, even these low angles are concealed by a
surface more nearly horizontal), but although the sea seems to be the
most likely cause for such an undulating surface, we do not generally
find that plains are bordered by old sea-cliffs. It may be said that
these could only be expected where an interval of rest took place
in the elevation of the land; yet while this seems reasonable, we
must bear in mind that something approaching to such an interval
appears to have been requisite for the production of a plain.
We may suppose, if the space between England and Ireland were
elevated above sea level, a large but not quite horizontal plain would
exist, with marked lines of cliff along each side: the ground would
be covered with recent marine deposits—rivers would drain the
water off, and yet it would be difficult to say that none of the con-
figuration of the land was due to old subzrial denudation, as we
know that land beyond the limits of the coast line of Ireland has
been submerged.
The old sea-cliffs would mark the passage from lower to steeper
near the latter of the above localities, and the ancient graveyard of Mahim, partly
washed away at the northern extremity of Bombay Island.
1 In his paper “ On River Valleys of the South of Ireland.” Quart. Journ, Geol.
Soc., London, Nov., 1862 (p. 402).
10 Wynne—Denudation and its Causes.
ground, such as we have no examples of around the plains which
now occupy so much of the centre of Ireland; but it is, perhaps,
hardly fair to speculate as to the entirely marine origin of these
plains from the appearances presented where the junction between
their old surface and its covering of drift is seen, as we cannot tell
how much of these appearances may be due to the action of field-ice
or other glacial agencies. However, if we turn to the elevated
plateaux of the Deccan in India, they afford even less positive
evidence of having been sea-bottoms, in the absence of rolled detritus
or wave-worn debris to indicate the approaches to ancient coasts, and
yet their character as plains is most strongly marked.
In many cases we are unable to say what the stratified conditions
of the rocks beneath such features may be; in many others we find
a rough parallelism between the stratification and the surface, and
in some instances we have underneath them bedded rocks, both flat
and undulating, as well as highly inclined. If any rule exists, it
may be indicated by the observation that where plains occur, the
rocks, if stratified, are often nearly horizontal; or if inclined and
contorted, or of igneous origin, they may have a certain general
equality of texture, resulting from a wide extension of one kind of
rock, or from a greatly jointed, cleaved or frangible condition, such
as would facilitate their destruction by sea-breakers.
It is no new observation that rain seems to act vertically, its
tendency always being to produce steep ground where it is not
accumulating materials—thus we are obliged, in the absence of any-
thing more likely to produce them, to attribute the formation of
plains to the action of the sea.
Conclusion.—In concluding these observations it need only be said
that the consideration of this subject strengthens the conviction that
all the forms of the land cannot be fairly attributed to any one kind of
denudation with which we are acquainted :—that the similarity of the
general resulis notwithstanding differences in the causes from which
they may have proceeded, and their close connexion with geological
structure, involves their origin in some obscurity, which may lead to
error, if a prejudice exist in favor of either marine or sub-aerial
agency, and that while great changes are effected by the endless
action of the sea, the equally continuous atmospheric agencies are
sufficiently powerful to produce, in the lapse of time, results so enor-
mous, that time also is required for their full appreciation.
EXPLANATION OF PLATES.
Prats I.
Fig. 1. Sketch of a Trappean hill at Wassid, near the foot of the Inclines by which
the Great Indian Peninsular Railway crosses the Western Ghats.
2. Part of a Sketch from the elevated hill-station of Matheran, between the
Ghats Proper and Bombay (Trap-rock).
3. ‘The Old Man Rock,” formed (as well as can be recollected) of purple Grit :
mouth of Bull’s Creek, South side of Dingle Promontory, Ireland.
4. Sketch from the brow of Benluben Mountain, in Sligo. -4. Fissure be-
ginning to open. ZB. Detached pinnacle of rock. :
5. Bein of part of a long Cliff-terrace on Benluben Mountain, County of
g0.
Green—Carboniferous Rocks of N. Wales. 1
Prats II.
Fig, 6. Coomassig Cliff, 1100 feet high, forming one side of a glen or coom, near
Sneem, Co. Kerry, Ireland.
7. Tnnishnabro, one of the Blasket Islands, off the coast of Kerry. The nearly
vertically-bedded rocks are pierced by large openings, one above another.
8. Lines of dislocation or division in Drift, (sand, clay, and gravel,) at Golden-
grove, Co. Tipperary, Ireland.—(See Explanation of Sheet 126, Mems.
Geol. Survey of Ireland).
IJJ.—On toe Lower Carsonrrerous Rocks or Norta WALES.
By A. H. Green, M.A., F.G.S.
sh is well known that, though the Coal Fields of Lancashire and
North Wales are now parted from one another at the surface
by a broad tract of New Red Sandstone, there is reason to believe
that the two are connected underground, and are both parts of one
and the same great deposit; and that the beds which in Lancashire and
Cheshire dip out of sight below the Red measures, reappear in Flint-
shire and Denbighshire. Attempts have been made, I believe, to
identify the individual coal-beds of the two districts, but I do not
know with what success. During a short stay at Llangollen, some
years ago, I ventured on a like task for the Lower Carboniferous
Rocks, and though the time at my disposal allowed of only scanty
observations, these were recorded in my note-book, in hopes that an
opportunity might occur of filling in the sketch thus roughly traced
out. No such chance has befallen, or seems likely to befall me, and
in the hope that the notes I then made may aid some one who, with
more leisure, is willing to attempt a full solution of this problem, I
now put them forward as a rough approximation.
The beds between the Coal Measures and the Mountain Limestone
in North Wales have generally been classed as Millstone Grit, but I
must beg leave to draw attention to the fact that this designation
is an excessively vague one, the limits of that sub-formation being
very differently defined by different authors. We must therefore,
before we can have any definite meaning in calling a group of
beds Millstone Grit, state whose classification we are following.
In the present paper I will use that laid down by the Geological
Survey for the Carboniferous Rocks of Lancashire, which is as
follows :—
Lower Coan Measures.
{ First Grit, or “‘ Rough Rock.”
Shale.
Second Grit, or “ Haslingden Flags.”
gene ne 4 Shale. (‘‘ Brooksbottom beds.’’)
; Third Grit. (First millstone of some authors.)
Shale.
| Fourth Grit. (The second millstone of some authors.)
Shales.
1. | Yoneda Grit.
Shales.
Rocks. 2. Yoredale sandstones.
3. Black shales with thin earthy limestones.
CaRBONIFEROUS oR Mounrarn Limestone.
My wish was to determine whether the above sub-divisions, or any
YOREDALE J
|
L
12 Green—Carboniferous Rocks of N. Wales.
of them, could be recognised among the Lower Carboniferous Rocks
of North Wales, and I came to the conclusion that the Millstone Grit
is there feebly represented, and that the greater part of these beds
is more likely to be the equivalent of a portion of the Yoredale
Group.
I ited I shall not be thought guilty of presumption if I seem to
differ from the eminent geologists who have called the whole of the
rocks under consideration Millstone Grit. These authors seem to me
to have used that name in a wide and somewhat vague sense, mean-
ing by it, any sandstones which are found between the Coal Measures
and the Mountain Limestone; and they would, I have no doubt,
have classed as Millstone Grit, the beds which, under the scheme
just given, form the two upper divisions of the Yoredale Rocks. The
difference is thus, after all, one of words! only; and all I can claim
is to have endeavoured to give a rather more detailed account of
these rocks, and to fix more definitely their place in the geological
scale; with what success further research must determine.
The rocks I was able to examine cover a belt of country, about two
miles broad, between the Flintshire Coal Field and the Mountain
Limestone of the Eglwysegle Rocks, and consist of sandstones parted
by beds of shale. ,
A good section of the lowest beds is seen near Tan-y-Castell, one
mile and a quarter north-east of Llangollen. It is figured in the
woodcut below, and shews the following beds, in ascending order.
Srotron No. 1.
{ 1. Solid grey limestone. ,
Morirkine clo meget thinly bedded, somewhat earthy. Corals and shells in
enty.
SERENE gy Flaggy Tiesto sandy, and holding here and there many small
l quartz pebbles. Band of encrinital limestone at the top.
4, Very closely-grained hard sandstone, highly quartzose, with small
white quartz pebbles, most likely a calcareous cement, weathers
into a honey-combed form.
5, Finely grained, softish sandstone, here and there full of small, white
quartz pebbles.
A. Light sandy drift, pebbles of slate and igneous rocks.
B. Boulders of various igneous rocks.
efi’ wi a2 2 2 4
so, <> Tigien eG Gr or
ef HY i] Hh ES So FOP EP ONS tia Se Seo
OU a a
1
SEcTION ACRoss THE E@LwyseGLE Rocks, NEAR TAN-y-CASTELL.
\
Though not immediately connected with our subject, the gradual
passage upwards from the limestone into the sandstones is worth
1 A recollection of this fact would have saved much needless controversy as to which
of the many schemes for the subdivision of the Lower Carboniferous Rocks is most
natural. All must be alike artificial and matter of convenience, for the simple reason
that, with local exceptions, the Carboniferous Group is conformable from top to bottom,
and so no lines of subdivision have been marked out in it by nature. One scheme
may be more handy for certain districts, or more suited to individual taste, than
another, but this does not make it more natural.
Green—Carboniferous Rocks of N. Wales. 138
notice. The upper beds of the former were in places full of small
pebbles of white quartz, and the bed (No. 4) seemed at times to pass
into a limestone.
The sandstone (No. 4) forms a ridge to the east of the limestone
cliffs, and if we follow this northwards for a couple of miles or so we
come to a deep valley running down by Tyfynuchaf, along which the
rest of the sandstone group is laid open in the brook course, showing
us the following beds :—
Section No. 2. (Beds in ascending order.)
. Sandstone (No. 4) of the former section.
. Gap, no section.
Thinly bedded, shivery, cream-coloured rock, with a smooth marly
fracture, (Productus, Spirifer).
. Gap, no section.
Hard, finely-grained, light-coloured grit.
. Short gap, no section.
Hard, grey, sandy shale.
. Hard finely-grained grit.
. Black shale, about fifteen feet thick, with a band of earthy limestone
containing Productus, Spirifer, and Polypora.
. Closely-grained grit, some of it coarse.
. Very coarse, massive, rough grit, and conglomerate, containing
much felspar, the decomposition of which makes the rock
crumbly.
Goan 12. Dark shale.
M 13. Coal, with Ganister floor.
BASURES- (14. Hard closely-grained sandstone.
The thickness of the beds, from No. 1 to 11 inclusive, is shown by
the sections of the Geological Survey to be between 800 and 1000
feet.
‘About three miles east of Llangollen I got a good section of the
bed No. 11, and there a coal about 1ft. 6in. thick lay very close on
the top of the grit.
These were all the observations I was able to make, and I grant
they are scanty enough, but the characters of some of the rocks are
so marked that I felt sure I recognised in them some well-known
acquaintances of Lancashire and North Staffordshire.
And first, No. 11 has all the distinguishing marks of the Rough
Rock of those counties, and it has besides lying upon it a coal which
may correspond to the Featheredge Coal of Lancashire.. The highly
felspathic character of the bed is the guide I trust to most, but be-
sides that there was a likeness not easy to deseribe in words, but
perceptible to a practised eye.
I failed, however, to find among the sandstones below this bed
anything that bore a resemblance to the lower gritstones of Lan-
cashire ; all the grits of the Welsh section, from No. 10 downwards,
had a common stamp, were very closely grained, highly quartzose,
rung under the hammer, and broke with a clean, bright fracture.
In this respect they agree very well with the shape which the Yore-
dale Sandstones wear in the neighbourhood of Leek and Congleton,1
HS OONAGHP wre
ae
1 See ‘Geology of the country round Stockport, Macclesfield, Congleton, and
Leek.” (Memoirs of the Geological Survey of Great Britain.) p. 17.
14 Wyatt-Edgell—On the Genera of Trilobites.
and I think they are more likely to be the equivalents of this group,
than of any other of the Millstone Grits.
The presence of Mountain Limestone Fossils, and the band of
earthy limestone in No. 9, is in favour of the Yoredale affinities of
these beds. Such remains and like limestones are common in the
lowest, and perhaps occur sparingly in the upper, Yoredale Groups
of Lancashire, Staffordshire, Derbyshire, and the West Riding of
Yorkshire ; but I do not know a single case of any such beds in the
Millstone Grit of those districts.
I am inclined to think then, that the Millstone Grit is represented
in North Wales by its uppermost member, the Rough Rock, alone:
and that all the lower beds have thinned away before we reach
Flintshire. This agrees with what we know happens elsewhere to
this sub-formation as it is traced southwards.
It also seems that the sandstones underlying the Rough Rock
are, in mineral character and fossils, more closely related to the
Yoredale than to the Millstone group; and that in many respects
they agree very well with the middle division of the Yoredale beds
as seen in North Staffordshire.
Valle Crucis Abbey and the bridge at Llangollen are built, I think,
of some of these, supposed Yoredale, sandstones: they have stood
weather admirably, the carving and tool marks being as fresh as
when first cut.
TV.—On toe Genera or Trinopires AsapHus AND OGyYGrA AND
THE SuB-GENUS PrycHOPYGE.
By the late H. Wyarr-Epeex1,! Esa., 13th Light Infantry.
Y the able investigations of Mr. J. W. Salter, the various species
of British Trilobites are now being systematically described, and
referred to the genera to which they properly belong,’ the Asaphide
with the rest ; but there seems to be still some doubt as to the true
differences between Asaphus and Ogygia. The feature apparently con-
sidered distinctive in the masterly work alluded to, is the form of
the labrum ; which, if fureate, is to be set down to Asaphus; if ob-
tusely pointed, to be the distinguishing mark of Ogygia. How
Ogqygia peltata (Woodcut, Fig. 5) can be reconciled to this division,
I do not see; but the main difficulty in the way of this classification
is the sub-genus Ptychopyge of Angelin—distinguished by “having
the facial suture within the margin in front.” This sub-genus
Mr. Salter shows to be represented in Britain by Ogygia Corndensis,
Murchison (Woodcut, Fig. 1): it is called Asaphus by Angelin,
and has the wide axis, short and broad pleural furrows and simple
caudal ribs of that genus. In addition to these features, the
course of the facial suture finds a parallel in the sub-genera of
Asaphus, Isotelus, (Dekay) and Cryptonymus (Hichwald) ; Mr. Salter
1 From a M8. found amongst the author’s papers.
2 See Mr. Salter’s monographs on British Trilobites, published by the Palzonto-
graphical Society. Part I., 1864; Part II., 1865; Part [II., 1866. It is to these
two latter parts that this paper specially refers.— Edit.
Wyatt-Edgell—On the Genera of Trilobites. 15
cites but one species of Ogygia that bears resemblance in this
respect." Yet with all the stamp of an Asaphus, Piychopyge Corn-
densis has the obtusely-pointed labrum common to Ogygia Buchii and
O. Selwynii. (See Woodcut, Fig. 2.)
Fig. 1.
Fig. 1. Asaphus (Ptychopyge) Corndensis, Murch. Llandeilo Flags, Builth. Fig. 2. Labrum
of same. Fig. 3. Labrum of Ogygia scutatriz, Salter. Fig. 4. Labrum of Asaphus tyrannus,
Mureh. Fig.5. Labrum of Ogygia peltata, Salter. (Drawn from a sketch by the Author, after
figures upon Plates XVI., XVII., and XXII., of Mr. Salter’s Monograph. ]
The question arises whether the form of the labrum is to be con-
sidered of such importance as alone to distinguish genera. The
fact of the labrum of Ogygia peltata (Woodcut, Fig. 5) (which is
an unmistakeable Ogygia, with narrow axis, remote fulcrum, and
duplicate ribs to the tail) not being symmetrical, would make one
think that too much stress has been laid on this point. The
labrum has two small auricles, and slightly resembles that of
Asaphus tyrannus (Woodcut, Fig. 4). Ogygia scutatrix, so nearly
allied to O. peltata as to have been formerly confounded with it,
has a symmetrical, almost rectangular labrum (Woodcut, Fig. 3).
Thus the shape of this organ differs exceedingly in these two very
similar forms. It may be added that in Ogygta Selwynit, which
makes the nearest approach to Asaphus of any species of its genus
(as here defined), the labrum is obtusely-pointed, though broad; so
that, if its form were to be considered a generic distinction, the two
last-named species would have to be separated from the first. But
no, it is evident that they cannot be—surely we must look to other
features to mark the genus ; and this being the case, Ptychopyge must
be separated from it to take its place as Asaphus.
Therefore setting aside the labrum altogether, the differences be-
tween Ogygia and Asaphus can be summed up as follows :—
1. Ogygia is not generally so convex, and has the fulerum farther
removed from the axis.
2. In it the pleural furrows extend farther, and have the appear-
ance of incisions, not that of broad grooves.
1 OQ, dilatata Dalman, a foreign species.
16 Liitken—On Pentacrinites and Sea-Liles.
3. The tail-ribs are duplicate. This is an essential difference.
4. The axis is, generally speaking, narrower, and its width is nearly
the same throughout: in Asaphus, the axis of the thorax
always greatly exceeds in width that of the tail.
These distinctions will draw a broad line between the two genera,
and will separate the British species belonging to them as in the list
that follows. There will be no intermediate or doubtful forms, with
the exception of Ogygia? hybrida,—of which the tail only has been
hitherto discovered.
Asapnus—(Basilicus) tyrannus, Murch. Llandeilo Flags, Llandeilo.
peltastes, Salter. Llandeilo Flags, Llandeilo.
Powisii, Murch. ° Llandeilo Flags, Anglesea.
Marstont, Salter. Caradoc Shale, Horderley, Shropshire.
laticostatus, McCoy. Llandeilo Flags, Builth.
> radiatus, Salter Caradoc, Rhiwlas, near Bala.
(Ptychopyge) Corndensis, Murch. Llandeilo Flags, Builth.
(Lsotelus) gigas, Dekay. Caradoc Rocks, Tyrone.
afinis, McCoy. Up. Tremadoc Slate, 8. of Portmadac.
Homfray?, Salter. Up. Tremadoc Slate, near Tremadoc.
(Brachyaspis) rectifrons, Portl. Lower Silurian, Tyrone.
(Cryptonymus) scutalis, Salter. Caradoe, ‘Tyrone.
Ocye1a— Buchii, Brongn. Llandeilo Flags, Builth.
ss var. convexa Llandeilo Flags, Builth.
55 var. angustissima. Llandeilo Flags, Builth.
Lr. and Up. Tremadoc and Arenig
tatairiz, Salter aby,
Eee : Tremadoc, ‘Portmadoc, and St.
David's.
peltata, Salter. Arenig Group, St. David’s.
} Selwynii, Salter. Arenig Group, Dolgelly.
(?) hybrida, Salter. Llandeilo Flags >— Carmarthenshire.
IN@Ow ners) Ole | Ms VE@AeS
’ SS
T.—On THE PENTACRINITES OF THE WEST INDIES; WITH SOME REMARKS
ON PENTACRINITES AND SEA-LILIES IN GENERAL.!
By Dr. Curistian Liirxen, Assistant Zoologist in the Museum of Copenhagen.
Translated from the original Danish, by Dr. Gustar Linpstrém, of Wisby, Island
of Gotland, Sweden.
N this very elaborate memoir, the author first describes a new
species, Pentacrinus Miilleri, and gives an excellent plate of the
animal, natural size. He then gives an account of the other
Crinoidea (Pentacrini, Holopus, etc.,) which have been found, or pre-
tended to have been found living, but the knowledge of them seems
to be very scanty and unsatisfactory. Next, Dr. Liitken compares
the Pentacrini with the genus Alecto, and states, that these genera
belong to the same natural family. The nearest allies of the Pentacrini
are, nevertheless, the extinct tertiary forms, (the true Pentacrini
from the London Clay, and the genera Isocrinus, H. v. Meyer, and
Cenocrinus, E. Forbes). Of these Dr. Liitken considers the last as
1 Om Vestindiens Pentacriner med nogle Bemarkninger om Pentacriner og Solilier
i Almindelighed of Dr. Phil. Chr. Liitken. Af Naturhist. Foren. Vidensk. Med-
deleser 1864.
Liutkhen—On Pentacrinites and Sea-Lilies. 17
undoubtedly a true Pentacrinus, and. the former only asa slightly
deviating sub-genus. The magnificent Pentacrinas of Jura, (P. briarcus
and P. subangularis) differ in a higher degree as in the more branch-
ing arms, in the small radiaria, and in the solid plates of the perisoma.
As to the true confines of the family of the Pentacrines, the author
thinks them very uncertain, and he also considers the question of the
arrangement of all sea-lilies in natural groups, still to be in a highly
unsettled state. Some have aranged them in articulated and tesselated,
(CRINOIDEA ARTICULATA and TESSELATA). Those naturalists who
acknowledge the CRINOIDEA ARTICULATA aS an independent order,
number all species, younger than the palzeozoic formations, excepting
Holopus and Marsupites, amongst them. ‘They consider all the Crr-
NOIDEA TESSELATA as Paleozoic. But Dr. Liitken thinks this opinion
untenable, and it seems to him impossible to draw definite lines
between them. ‘If you take to the definition,” he says, “‘ that those
Sea-lilies are articulated, which have the radialia of the pelvic cup
free, that is, articulated between themselves, not united by seams,
. . it may be answered that the Jurassic Apiocrinus has
the radialia united by small intercalated interradialia, and the radialia
are thus immoveable, and not free.’ Moreover, the Paleozoic
Taxocrinus has the radialia quite as free as the Pentacrines, and ought
therefore to be ranged amongst the CRINoIDEA ARTICULATA.
oO
o (e)
sGs of Se
Senfens (S SF
ane gf oi
Sag a
Eas B
229 2
258 =
Soe > 8
BO
PES ° we =f
Beg =o.
Baa 4 T°
aa? oO i= mM
abs 2 8 @
ee 4 te
B le iS
ace ° S
Oo i=
oo B
hen on
aces o 2
Op a —
Ons an oO
pas, * 6
FS 2
ao mn
a
te & da.
Bec oe Sues
ease o =
oae 8 Bee =
Sa ° > Sjq se
setall =) 5
poo a ane 5
ace Sf MSE og
Bao a Grsy, =]
Oo . —
ae ee i)
ae Z
2 5
appr & D
wm
aes we ene re
° = RO or
soa op
fee 8 2s
2 5b st
eae B B
Or +) =
toe B 5
ou @ g
0 Bs n
Sis el
Boo ®
pee a
onf =
— .
B84
eaecl=a
Fak
Bee &
a2e
BBs &
n“se =o
eg 4 2
2 & ee
x55 8
SE a By
ages ae
a & $4
Sl =a! a
368 ny
oe ay
aah Roy
by me in the sections in your numbers for February and March
last.2 This is the most important of all, because it affects a
1 There are two brickfields in the lane, this is in the nearest to Wickham church.
2 Gzoz, Maa. Vol, III. pp. 57 and 99.
40 Correspondence.
formation as much newer than the Drift as is implied by its occupa-
tion of a trough cut down, in its deepest part to more than 500 feet from
the upper Drift; and because it is also in intimate connexion with the
disturbances under which the Thames gravel emerged. In the sec-
tions I gave in your Magazine, space necessitated this being shewn
as a vertical drop, but in reality it arises from a pitch in a north-west
direction, as the following detailed section shows :—(See Woodcut,
Fig. 2.)
These are instances in which actual ocular evidence of violent
dislocations is obtainable. There are many more which are deduci-
ble from the structure of the crag and Drift, and I believe that many
of the sections in these upper beds which present perplexing features
are due to this cause. Thus the capping of Boulder-clay which rests
on the Chillesford beds, at Chillesford, and which Mr. Fisher, in his
paper, read before the Geological Society, brought into his evidence
of “trail,” I believe is nothing but an oblique throw of the upper
Drift, on to the Chillesford beds ; for in a pit, only a furlong and a half
north of this section, there occurs one of the junction of the upper
and middle Drift, which shews both these formations in strict con-
formability to each other, and arching under the influence of lateral
pressure, somwhat in the same manner in which the beds are ex-
hibited in the section of Aldringham church.
T am, Sir, etc., Seartes V. Woop, Jun.
“FAULTS IN THE DRIFT AT HITCHIN.
To the Editor of the GrotocicaLn Macazinr.
Dear Sir,—My friend, Mr. A. H. Green, who is nothing, if not
critical, has been very gentle in his criticism in my case; and,
indeed, he is so genial a man that I am sure it must go against
his grain, and be an act of stern duty in any case to find fault at all.
Perhaps this may be the reason why he overlooked the faults at the
Hitchin station. I can hardly think they have grown larger since
his visit. But there they are; and confused as the mass of gravel
and loam, which form the Boulder-drifts in that locality, may be,
there is a tell-tale bed of conglomerate at the bottom which has
betrayed all its movements—while surely, not even a tyro could
mistake the dark brown gravel which caps the drift and fills the
pipes, and which is so common in the Hitchin section, for the light-
coloured sand and loam below.
The uneven surface of the Chalk here is indeed due to the same
cause which has produced so many inequalities in the surface of our
island—viz., the much-abused “ unequal elevation ” of faulted ground,
however these faults may have been produced. In the case of the
Chalk, that may, no doubt, in some cases be due to sinkings over
subterraneous cavities produced by rivers and streams in Post-glacial
times. For this idea I am indebted to my friend and former col-
league, Mr. Thomas T. Mc K. Hughes, with whom I had previously
examined the Boulder-drifts near Hertford, and therefore came to
the section more prepared for examination than I should otherwise
have been.
Correspondence. 41
Whether this or a larger movement be the source of the ap-
pearances at Hitchin, I do not mean now to argue.’ But that the
clean-cut faults, passing through Chalk, pebble bed, and loamy
gravels, exist in this locality, only needs a second visit to ascertain.
Indeed, as I hope I fully mentioned in a note to the paper (for I
have not the Journal at hand), one of these faults have been
previously marked in the sections given by Mr. 8. V. Wood, jun.—a
fact I was not aware of when the paper was read at Somerset House.
After all, in most cases, we only see what we look for; and if
I had been examining the Chalk specially, I should probably not
have seen these dislocations. I am sure your correspondent could
not have been long at Hitchin without making many good friends
there, so I shall recommend him to go and dine with some of them
this holiday time, and pay a visit to the old chalk-pit again.
I am, yours truly, J. W. SALTER.
MALvern, Dec. 3rd, 1866.
GLACIATION IN DEVON AND ITS BORDERS.
To the Editor of the GrotocicaL MaGazInE.
Srr,—I have always distrusted my own power of observation in
Glacial and other superficial phenomena, for whenever I have made
an observation to a regular glacialist, or “drift describer,” I have
generally had to stand corrected. It would not, therefore, be at all
surprising to me to find I was quite wrong in my conclusions as to
what appeared to me to be a glaciated surface on the cliff on the .
banks of the Exe above Barlynch Abbey.
The first time I ever was able to see these phenomena of rounding,
moulding, and striation, so as to recognise them, was in the S.W. of
Ireland, about the year 1851, under the guidance of the late Sir
Henry DelaBeche. Since then I have had many opportunities of
observing them not only in Ireland, but in other parts of the British
islands and in the Alps.
Coming down the valley of the Exe on the occasion described in
the letter published in your Magazine in 1865 (Vol. I. pp. 478),
I saw before me a cliffy ridge marked, as it appeared to me, pre-
cisely in the same way in which so many so-called glaciated surfaces
are marked.
These markings being large and obvious, and my time being all
too short for geological observations of much greater importance,
I did not spend more than ten minutes in examining them. If, there-
fore, they are not glacial as my friend, Mr. Pengelly and Mr. Vicary,
have concluded, it only assures me of the wisdom of the old pro-
verb, ne sutor ultra crepidam, and warns me to stick to the rocks
themselves, and leave their external markings and superficial
covering to those whose tastes and powers of observation are more
suited to them than mine are. I hope, however, that some practised
1 J mayas well observe, that the faults at Hitchin station, large and small, are very
nearly parallel to one another—as in most of our faulted districts. I think this indi-
cates a more general movement than is implied in the idea of subsidence over cavern-
ous ground, such as may account for the minor flexures in the drift gravel.—J.W.S.
42 Correspondence.
glacial observer may visit the locality some day, and give us the
benefit of his opinion upon it. In the meantime, as Mr. Pengelly,
in his letter in your last number, agrees in the correctness of my
description of the facts, perhaps he will favour us with his ideas as
to their origin, for I certainly have never seen anything like them
except on a so-called glaciated surface.—Yours truly,
Dusty, Dec. 4, 1866. J. BEETE JUKES.
DR. FRAAS ON PRE-HISTORIC SETTLEMENTS.
To the Editor of the GroLocicaAL MAGAzinE.
Srr,—In your impression of this month (page 550), Dr. Fraas
concludes an interesting article on Pre-historic Settlements with two
remarks, thus: “And, secondly, that the discovery at Schussenried
indicates a totally different climate, such as now begins at 70 degrees
of north latitude.” But he gives a fact which fully contradicts this
theory. The remains of horses were found at Schussenried. “In one
case the skull is still nearly perfect, and it belonged to a species with
a large head ; while certain bones of the extremities indicate a strong,
bony, and powerful animal. The brain cavity has been opened, the
vertebra had been split, and the bones containing marrow had been
broken in pieces, so that there can be no doubt of horse-flesh having
been one of the table delicacies of the ancient Swabians.” Are
there wild horses at the North Cape now? or in Nova Zembla ? or at
the Samoyede Promontory ?
I have the honour to be, Sir, your obedient servant,
GxroRGE GREENWOOD, Colonel.
Brooxwoop Park, ALRESFORD,
December 7th, 1866.
THE DEVONIAN ROCKS OF NORTH DEVON.
To the Editor of the GkoLoGIcaAL MAGaziIne.
Dear Srr,—I wish I had power at present to enter the lists
on the new issue raised by Professor Jukes as to the integrity of the
Devonian system. It seemsso odd to try to explain away a series of
rocks which must have some place, and are distinguished, as all
know, by a peculiar set of fossils. Though the Devonian has not
many striking peculiar types of shells, it has some quite distinct,
while the mass of its species are undoubtedly peculiar, and neither
Silurian nor Carboniferous. And it is 10,000 feet thick !
Meanwhile, till 1 have more opportunity, let me just keep your
younger readers in possession of the facts that in North Devon, pro-
ceeding southwards from Linton and the N. Foreland to the
Culm-measures, there are the following distinct series, which Pro-
fessor Jukes rather summarily groups into Coal, Carboniferous-slate,
and Old Red. I know “arose by any other name will smell as
sweet,” but I prefer the well-known names :—
1. Slates and sandstones of Linton and the North Foreland (Lower
Devonian).
- 2. Grey slates and limestones of Combe Martin and Ilfracombe
(Middle Devonian).
Correspondence. 43
3. Purple grey grits and slates—Morte Bay, etc. (Upper Devonian
? no fossils).
4, Marwood sandstones and Pilton and Barnstaple group (Upper-
most Devonian).
5. Dark soft Carboniferous shales—Barnstaple and Fremington
(Carboniferous slate).
6. Limestones and Culm Measures (Mountain Limestone, Mill-
stone-grit (and Lower Coal ?).
Now this succession has been made out by De la Beche, Sedgwick,
Murchison, Phillips, and others; and I have verified a good deal of
it myself. Let us understand each other. Iam glad to see that Pro-
fessor Jukes has lately covered more of the ground ; and I am sure, if
he spends more time in both North and South Devon, he will end
by agreeing with his geological brethren. Already he perceives the
resemblance in what we call the Lower beds (No. 1), and in No. 8,
to the Old Red, as he knows it so well in the South of Ireland.
And if he will remember that, in S.W. Ireland, the Upper beds of
the Old Red Sandstone lie unconformably on its mass, just as they
do in Scotland (Geikie), and through Wales, right away into Pem-
brokeshire, he will see the importance and extent of the duplex
formation which he is endeavouring to supplant. If, indeed, he can
find us true Carboniferous fossils in the three lower divisions, we may
yield the point to him. Hitherto they have only yielded Lower and
Middle Devonian species. No. 4, as he well knows, is the repre-
sentative of his own ‘‘Coomhola grits,” which in Ireland lie, at all
events, at the base of the Carboniferous slate, and which I have
proved to be of the same age as the conglomerate beds (or part of
them) of the Upper Old Red in Pembrokeshire. And I have also
shown that No. 5 contains Carboniferous fossils only. If, therefore,
the uppermost members of the Old Red are equal to the uppermost
member of the Devonian, why not make room for the lower, which
cover the Silurians ?—I am, yours truly, J. W. SALTER.
FLINT CORES FROM THE INDUS.
To the Editor of the GrotocicaL MaGazine.
Sir,—With reference to my letter in the October number of the
Gzorocican Magazine (Vol. III. p. 4383), on some Flint Cores
found by my Son, Lieut. Edward D’Oyly Twemlow, of the Royal
Bombay Engineers. When he wrote last, about 20 feet of water
covered the place, but he has from memory defined the exact spot
and depth in the accompanying sketch.
Section on the River Indus, near Sukkur Pass, Upper Scinde.
The lower limestone rock is not seen in the above section, but crops
up about 400 yards away from the river, with an upward inclination.
The upper 30 feet (c) is found in layers of one and a-half to two
44 Correspondence.
feet in thickness. Above this occurs a band, six inches to one foot
in thickness, of nummulitic limestone in loose slabs. Again, above
this occurs (b) a mass of flints, packed together, in layers of from
one and a-half to two feet in thickness. This is covered by (a) a
recent silt deposit (alluvium) of the river, exactly similar to what
lies over the whole of Scinde. In the deposit (b) at the point (d),
the flint-cores were found, four feet beneath the surface, and 20 feet
below the dotted line (1), the level of the highest flood: (2) is the
line of lowest flood level.
I enclose a seecimen of the limestone,’ and also some granular
bodies, found with the flint-cores.?
My Son is sending home several more examples of flints from this
deposit.—I remain, Sir, yours faithfully,
Grorce Twremiow, Major General.
Poyiz Lopex, Guinprorp, 1866.
THE BRITISH ASSOCIATION AND THE NATURAL HISTORY FIELD-
CLUBS AND GEOLOGICAL SOCIETIES.
To the Editor of the GrotocicaL MaGazinu.
Sir,—I wish to call the attention of your readers to a rather
important subject. How is it that the authorities of some of our
Field-Clubs fix their meetings for the week of the British Associa-
tion meeting? It can hardly be intentionally done; but common
sense would dictate, that when such a mistake has been made, it
should be rectified as soon as discovered by altering the day. Now
both the Malvern and the Woolhope Clubs held their meetings this
year during the British Association week, to the annoyance of those
members who wished to enjoy both. What most surprises me, how-
ever, is, that my friend the able President of the Malvern Club, who
is such an enthusiastic man of science, should have made such ‘a
“ faux pas.”
I trust you will insert this in order to guard against similar care-
lessness next year.—I remain, Sir, your constant reader,
Lupiow, 19th Nov., 1866. Ropert LicutTBovy.
MISCHiIDLANHOUS.
See eeetipgreeemneet
Prorrssor SEpDGwicK, the occupant for nearly fifty years of the
chair of Geology at Cambridge, in commencing his annual course of
lectures,* stated that he should not be ‘able to deliver his lecture on
the following Friday, having to meet his oculist, his sight being very
much impaired; nor was it, he said, surprising, that one so far
advanced in life should be infirm, for this, if it pleased God to spare
him to complete it, would be the forty-ninth course of lectures
which he had delivered as Woodwardian Professor. Reviewing the
history of his professorship, founded in 1734, he said that practically
1 The Limestone is true Nummulitic Limestone full of WV. laevigata.—Ed.
2 The granular bodies are pisolitic grains of Iron-ore, They have since been pre-
sented to the British Museum.—Kd,
3 October 21st, 1866.
Miscellaneous. 45
no lectures had been delivered by any of its holders until he received
the appointment, after a severe contest, in 1818. The science of
geology was always looked upon then as dangerous and suspicious,
and he mentioned one attempt to lecture which had been nipped in
the bud, it was said, by a hint from high quarters. Another difficulty
was that the founder of the professorship had decreed in his will
that the lectures should be in conformity with his own theory of
geology—a theory, said Professor Sedgwick, the most wild and
irrational. It amounted to this, that at the deluge the whole earth
was melted down into a sort of Irish “ stirabout,” but that, at the
same time, by some inexplicable, unaccountable contrivance, all
fossils, even the minutest, were preserved from the general de-
struction and handed down to us. Such a theory it was impossible
for a man to lecture upon who had anything like a conscience.
When he received the professorship, however, a grace of the Senate
made lectures a necessary preliminary to receiving the professorial
salary; and in the course he had adopted he had given a liberal
interpretation to the spirit of his founder’s will, and had endeavoured
to adapt his teaching to the progressive state of the science. ‘To his
founder, however, he gave all credit for having most religiously pre-
served the name of the locality from which every specimen in his
collection had been gathered ; and this in geology was of vast im-
portance. Still Woodward’s collection, as he (the Professor) found
it, was not sufficient to lecture upon, and, together with his friend,
the late Professor Henslow, he had set to work to increase it; and it
had gone on increasing till at last the difficulty was, not to find
sufficient to lecture upon, but to choose from so great abundance
what was best.—One very good remark the Professor made in
reference to geology and other physical science clashing with
religion: he said that those who had any faith worth the name in
the revelation on which their religion was founded would never fear
that which was impossible, that one truth would contradict another.
All truth was in harmony, and nature had this grand characteristic,
that she possessed no isolated phenomena—everything in nature was
regulated by beautiful fixed laws, and this preserved us from the
errors into which solitary phenomena would lead us. Taking up a
fossil that lay before him, the Professor said we knew that the
earth exercised an attraction upon it, tending to draw it to itself,
but we also knew this beautiful and wonderful fact that, by that
same law of gravitation, it was connected not only with the earth,
but with every particle in the universe. In conclusion the Professor
cautioned his hearers not to fall into the error of the so-called positive
philosophers, who, with all their boasted worship of Nature, fail to
render homage where homage is due. For a man to be profound in
his worship of Nature, without being also profound in his worship
of the Creator of Nature, seems as irrational as it would be for a man,
sitting at one of our grand Norwich festivals and having his soul
stirred within him by the almost heavenly harmonies, should feel
impelled to give expression to his emotion, and instead of rendering
his tribute of praise to the master-mind who had conceived the
46 Obituary.
glorious music—should fall down and worship the kettle-drum and
fiddle-stick.—[Taken in part from Pall Mall Gazette, Oct. 26, 1866].
In the February Number of this Macazinz, Professor Huxley will
describe a new Saurian Acanthophilis horridus from the Chalk-marl.
It is allied to Scelidosaurus, Hyleosaurus, and Polacanthus.—R.E.
@Bikt UPA.
dali a a ;
We have to deplore the untimely loss of a young and most promising
paleontologist, Henry Aprian Wyarr-Enertt, who died of dip-
theria, at Belfast, Nov. 6, 1866, aged 19. He had become dur-
ing the last few years well known to collectors and students of the
older fossils, and his. talents and zeal bade fair to place him ina very
prominent position in geological circles, when the results of his close
study should be given to the world. He had not yet published more
than a paper or two, one of which will be found in the present
Number, at p. 14, and another in Vol. I]. p. 160.1 But his acumen
and industry in this, his favourite pursuit, would assuredly have
given him a high title to consideration had his young life been
spared but a little longer. :
Ensign Wyatt-Edgell was born May 17, 1847. He was the
second son of the Rev. Edgell and the Hon. Henrietta Wyatt-Edgell
of Stanford Hall, Leicestershire. Ata very early age he was placed
at the College of St. Louis, Paris, where before he was eleven
years old he was honorably distinguished for classics; he acquired
his first taste for geology from the teaching of Mr. Charles D’Orbigny.
In 1858 he left the College of St. Louis, and afterwards passed three
years at Eton, where he distinguished himself in mathematics, and
completed his education at Sandhurst, entering second on the
examination list. He obtained a commission without purchase in the
59th Regiment, from which he exchanged into the 13th. In the last
six or seven years of his short life his whole leisure was given to
the collection and study of the Silurian and Cambrian Fossils. In
this wide and almost unoccupied field he had the friendly assistance
of several fellow-students, and willingly devoted himself to this
special group of rocks as most needing illustration. He visited
every available locality ; and his polished manners and winning
address gave him ready access to every cabinet. The testimony
of his friend, Mr. Salter, with whom he studied a good deal, is, that
for sound judgment of species and acute and critical observation of
their characters he was quite exceptionally eminent. Nothing
escaped his eye; and he was no less happy in the power of general-
ization in respect of generic groups and the relation of cognate forms.
To this power he added the charm of a classic taste, which rendered
his correspondence and. descriptions remarkably correct and clear—-
no mean gift, in these days of slovenly diagnoses. Several fossils
will be found to bear his name: e.g. Homalonotus Hdyelli, etc. ; and
1 See also a paper by him on the characteristic fossils of the Arenig group, and its
distinction from the Llandeilo, in Geol. and Nat. Hist. Rep. for July, 1866.
Obituary. AY
many new species, determined by himself, exist in his cabinet. A
paper on “The Division of the Upper Llandeilo Rocks by their
Fossils into an Upper and Lower Group,” was read by him in
1865 before the Geologists’ Association, and will be found in their
proceedings. Another on the Fossils of the Llandovery Rocks, and
a fasciculus of new species from his cabinet, were both in progress
when he left London for military duty in Ireland. The pack-
ages sent home from thence, to be worked up in the leisure which,
alas! never came, testify his devotion to his favorite pursuit to the
end. He will not easily be forgotten by those who knew him, and
the loss to our science is, indeed, a heavy one.
AtEexanpeR Bryson.—Alexander, eldest son of Robert Bryson,
was born at Edinburgh on the 14th October, 1816. He received his
early education at the High School, and being destined to pursue the
same occupation as his father, was apprenticed to a watchmaker at
Musselburgh. On the expiration of his apprenticeship, he went to
London for a time to obtain a further knowledge of the details of
clock and watch making, and on his return to Hdinbugh entered with
his brother Robert into a partnership, which continued up to the time
of his death. But, conjoimed with his mere business aptitude and
qualifications, was a strong taste for scientific inquiry and pursuits,
which led him, on returning from London, to enter as a student at
the University—the Chemistry and Natural Philosophy classes of
Professors Hope and Forbes. At the School of Arts, in the founda-
tion of which his father, along with Leonard Horner, had taken a
very active part, he was for some years a constant attender, and
frequently expressed himself as greatly indebted to that institution
for the opportunities of scientific improvement it had given him.
Mr. Bryson took an interest in the physical sciences generally, but
he devoted himself chiefly to the departments of mineralogy and
geology. Owing to a community of pursuits, a friendship early in
his life sprung up between him and the late Mr. Nicol, the inventor
of the well-known prism which bears his name, and who left him
not only a fine library and collection of minerals, but made him heir
to his property. With the distinguished naturalist, the late Dr.
Fleming, he was on terms of great intimacy. For many years they
made geological excursions together. In our scientific societies, or
elsewhere, no more strenuous defender of the opinions of that
eminent man was found than Alexander Bryson, and in the 22nd
volume of the Transactions of the Royal Society at Edinburgh, a
discriminating memoir of Dr. Fleming appears as the product of his
pen. Mr. Bryson was also long on terms of friendship with the
late Sir Thomas Makdougall Brisbane, for many years the president
of our Royal Society ; and to the Transactions of that body he com-
municated a memoir of that distinguished astronomer and soldier.
Few men, indeed, had so wide a range of friends and acquaintances
as Mr. Bryson; his general attainments, his frankness of manner,
and his unselfish and kindly disposition endeared him to all who
knew him. Mr. Bryson was an active member of the principal
48 Obituary.
scientific societies of Edinburgh. He was proposed as a Fellow of the
Royal Society of Edinburgh by Sir T. Makdougall Brisbane, and
was elected in 1858. He filled the presidential chair both of the
Royal Physical Society and the Royal Scottish Society of Arts, and
was also a Fellow of the Geological Society of London. ‘To the pro-
ceedings of these various scientific bodies he was a not unfrequent
contributor. His published papers are about thirty in number, and
comprise articles on geology, mineralogy, and zoology. In 1864 he
read to the Scottish Society of Arts an account of a new method
of detecting the presence and position of icebergs at sea, which was
considered of so much importance that the Hepburn Prize was
awarded to it. In 1862 he made a trip to Iceland, and published
a short description of his journey, one of the most interesting
results of which was the determination of the fact that the tempera-
ture half way down the tube of the Great Geyser was 270° Fahr.,
whilst at the very bottom it was not more than 240° Fahr. He was
elected a member of the Town Council, for Newington Ward, in
1861, which office he resigned on account of failing health, in
November last. During that period he took an active part in the
introduction of telegraphic communication between the various
police stations in the city. His brother Councillors testified their
opinion of his scientific abilities by appointing him last year one of
the Curators for the election of professors in our University. In the
spring of the present year, whilst engaged in making experiments to
test the applicability of the employment of the electric light in the
capture of fish, for which he obtained a patent, he contracted a
severe cold, which was shortly followed by an attack of jaundice.
He lingered on during the summer and autumn, gradually becoming
weaker, when an attack of bronchitis supervened, which in his then
debilitated condition rapidly proved fatal. He died on the morning
of the 7th of December at his house, Hawkhill, near Edinburgh.
On the evening of that day the Royal Physical Society held the
first meeting of its ninety-sixth session. After the minutes were,
read and approved, the president expressed his regret at having to
announce the death of Mr. Alexander Bryson, which had occurred
that morning, and moved that the Society should immediately adjourn,
as amark of respect to his memory. Mr. Bryson had long been
connected with and was one of the most active supporters of the
Society. He had filled the office of president, and at the time of his
death was a member of Council. The secretary was also instructed
to communicate with the members of deceased’s family, and to express
the deep sorrow of the Society for his loss. The motion was agreed
to, and the Society adjourned accordingly.
Spnor CastAna pI Prapo, of Madrid, For. Mem. G. S., died at
the close of 1866. He was Inspector-General of the Mines of Spain,
and was zealously devoted to the elucidation of its gelogy. A full
account of his principal work, ‘ Descripcion fisica y geologica de la
Provincia de Madrid” (1864), was given by Mr. Hamilton in his
Presidential Address to the Geological Society of London in 1866.
THE
GEOLOGICAL MAGAZINE.
No. XXXII.—FEBRUARY, 1867.
(GuBwlKG MEIN Naa Ga oe Se
— eee
1.—On tae ALLEGED HyprotTHERMAL ORIGIN oF CERTAIN GRANITES
AND Mertamorpuic Rocks.
By Davip Forszs, F.R.S., ete.
HE study of the crystalline and metamorphic rocks seems hitherto
to have been rather avoided by British geologists, who have
more exclusively devoted their attention to the stratified and fossil-
iferous deposits, and left this field of research all but entirely to be
cultivated by their continental brethren.
Latterly, however, the subject appears to have received some
attention from the members of the Geological Survey of Great Britain,
and the present communication is devoted to remarks upon the sub-
stance of two papers lately published by Mr. James Geikie, of that
survey, respectively entitled :—
I.—On the Metamorphic Silurian rocks of Carrick, Ayrshire.
Quarterly Journal of the Geological Society, vol. xxii. p. 513, et seq.
II.—On the Metamorphic origin of certain Granitoid Rocks and
Granites, in the Southern Uplands of Scotland. Gronocican Macazing,
Vol. III. p. 529, et seq.
These communications, coming from the pen of one of the staff of
the Geological Survey of Great Britain, are sure to arrest attention,
and they are written in a bold, and, if without offence it might be
added, somewhat dogmatic style, such as would be perfectly justifiable
if the views therein expounded are to be regarded as representing
general conclusions drawn from the deliberate and careful study of
the numerous examples of metamorphic action which must have
presented themselves in the course of the Survey; but which, if
considered in conjunction with several novel and rather startling
statements embodied in these papers, and which assuredly the author’s
colleagues in the Survey will not endorse, may probably be considered
as rather “de trop.”
The publications of the Geological Survey are generally, and
justly regarded, as master-pieces of geological and paleontological
research ; and what may be termed the extra-official scientific pro-
ductions of the members of the Survey fully sustain the high character
accorded to the official publications.
VOL. IV.—NO. XXXII, 4
50 Forbes—On alleged Hydrothermal
In the present instance, it may fairly be questioned as to whether
the papers here under consideration come up to the mark, and whilst
Mr. James Geikie deserves the geologist’s best thanks, for bringing
this intricate subject into the field of geological inquiry, and for
expressing himself with such decision and boldness as assuredly to
wake up the attention of such as have devoted themselves to similar
investigations, it must at the same time be regretted that the sub-
stance of the papers themselves does not prove the author to be
much at home either in chemistry, mineralogy, petrology, or physics,
and accounts for his placing such apparently implicit reliance upon
crude observations made in the field, and undervaluing the all-
important assistance to be derived from a knowledge of the collateral
sciences.
In a report on the igneous rocks of South Staffordshire,’ the
writer of these remarks stated, ‘In these investigations it is absolutely
essential that the chemist, geologist, and mineralogist shall go hand
in hand in the inquiry,” and nobody believes more thoroughly than
he does in the words of Mr. James Geikie, “that the question of the
origin of granite and other allied rocks will ultimately be solved by
the field observer.” But he wouldadd, however, “certainly not by
the mere field observer ; but by the man who, in addition to being a
correct field observer, brings into the field a sound knowledge of
chemistry and mineralogy, with the more mathematics and physics
the better, and who employs the microscope to assist his eye in the
examinations of the more compact or apparently homogeneous rocks.”
Tt must also be remembered that the progress of science demands
that the geologist, also, shall no longer put his whole reliance in a
pair of good legs, and plenty of field practice, but must avail
himself of every possible assistance and advantage afforded him by
the rapid strides of the collateral sciences: and depend upon it,
before this is done, such intricate problems as the origin of the
metamorphic and crystalline rocks, the formation of lodes, etc.,
-gtand but a poor chance’of solution.°
The writer does not speak upon the strength of an acquaintance
with this subject of a few months or years, but for more than
twenty years has continuously occupied himself in.a special and
minute study of the crystalline and metamorphic rocks, having
examined them in the field over a great part of Europe, North and
1 British Association Reports, 1865. Transactions of Sections, p. 43.
2 Geologists have not as yet learned to appreciate the true value of microscopic
-investigation, In very many cases the simple examination of a rock section can at
once determine whether a rock is a true igneous rock, or the product of a secondary
metamorphism. The admirable researches of Mr. Sorby show how much may be
effected in geologicalresearch by the use of the microscope. The writer, fully appre-
ciating this, has devoted much time and labor since 1851 to this branch of petrology,
‘and has now above 900 sections of crystalline and metamorphic rocks from about
480 localities, in different parts of the world.
3 Mohr in his Geschichte der Erde, 1866, p. 516, gives as No. 92 of his Theses,
“ Geologus non aestimatur ex calceis in peregrinationibus detritis ;’" it is admitted
‘that some geologists of repute are neither Palzontologists nor Petrologists, nor much at
home in either mineralogy, chemistry or mathematics: it becomes, therefore, some-
what perplexing to define what constitutes a geologist. ~ ve ‘
my
Origin of certain Granites, §c. SL
South America, Polynesia, part of Africa, ete., with all requisite
appliances at his command, and without having neglected the study
of chemistry or mineralogy ; but, even now, must confess that, like
most of the continental men of science who have made this subject a
special study, he has not yet been able to arrive at any such immediate
or sweeping conclusions as Mr. James Geikie, after his short examin-
ation of the Scottish rocks, has been so fortunate as to convince
himself of.
Without, however, being either a Neptunist, Plutonist, or Hydro-
thermalist, he believes that nature has employed all these and other
agencies in her metamorphic operations, and is fully prepared to
become a convert to Mr. James Geikie’s or any other’s views as soon
as a searching but impartial examination of the evidence brought
forward convinces him of their soundness.
Tn this communication it is not intended to comment upon or
question the accuracy of the local geology referred to in these me-
moirs; but it is proposed, as the real object of these remarks, to
examine into certain statements and arguments (quite independent
of purely local data) made use of by the author in the working out
of these memoirs, in order to convince himself of whether they are
sound or not, and thereby to arrive at a proper estimate of how far
conelusions dependant upon such data are entitled to confidence.
The perusal of these two papers would, he supposes, produce very
different impressions upon different readers: On the mere field ob-
server, after skipping sundry little passages, the science of which he
could not quite understand, the memoirs in question would read
well, smoothly, and plausibly, and in conclusion, probably convinced
by the boldness of the style and the apparently indisputable chemical
knowlédge of one who writes with such ease of chemical re-agents,
magnesian, alkaline, and basic properties of rocks, and explains the
actions of the alkalies, magnesia, etc., would, without further inquiry
into a subject which always had been a puzzle and a bore to him,
be quite content to accept all these new conclusions, and for the
future to believe that any stratified sedimentary bed, like grauwacke,
etc., can, by the wondrous agency of hydrothermal action, be con-
verted in sift into granite, minette, diorite, serpentine, porphyrite,
etc., etc., or any other rock. i
On the geologist, however, who possessed even a very small know-
ledge of chemistry or mineralogy, a very different impression would
be produced; he would at once perceive that the chemistry was in-
correct in points where even the merest tyro ought not to blunder,
and that, to say the least, the petrology was exceeding “loose;” and,
unless he determined to visit the localities and to. study the matter
for himself, would lay aside the memoirs with the intention of not
_putting any confidence in conclusions arrived at by the help of such
unsound data.
These remarks may appear severe, and although, as will be seen,
they admit of easy and indisputable proof, they have only been here
brought forward after serious consideration, and in the firm belief
that it is the duty of every geologist not to accept any new views
o2 Forbes—On alleged Hydrothermal
whatever, before he has submitted the data, upon which they are
founded to as strict and impartial a scrutiny as his own knowledge
of the subject permits.
Of such a scrutiny a short abstract is now given, and for con-
venience it is divided into several heads :—
(1) Chemistry Although Mr. Geikie admits “that the labours of
the chemist have been invaluable,” and that he has “no disrespect
for the work of the laboratory,” he generally finds a but or perhaps
to qualify his praise, and to show how much more dependence ought
to be placed in the field observer.
It is interesting, however, to observe how much chemistry he has
introduced into his first memoir, and how he endeavours to base his
entire conclusions thereon. From the style of this memoir (but for
its errors) it might have been written by a chemist, but certainly
not by a mineralogist or petrologist.
Every chemist knows that magnesia is the oxide of the metal
magnesium, and that it possesses no colour in itself, nor even the
property of communicating colour to its compounds, unless white be
regarded as a colour; and that, moreover, the minerals containing
magnesia are invariably colourless, unless some other element is also
present capable of communicating a colour to them.
Mr. James Geikie differs from chemists on this point, and appears
to have made the interesting discovery that magnesia is a colouring
body and has the property of colouring minerals green. Thus (p.
515, Quart. Journ.), he states that the magnesian matter colours the
rocks green, and when speaking of the greywacké of Peebleshire
states, (p. 518,) “‘ The beds have a greenish tinge from the abundance
of magnesian matter which they contain,” and all throughout the
memoir it is evident that he looks upon this new colouration test for
magnesia (greenness) as a means of assuring oneself of its presence
in rocks.
A well known mineralogist, when looking over Mr. James Geikie’s
memoir along with the writer, expressed his opinion that this mis-
conception was one likely to occur to a field observer from confound-
ing magnesia with serpentine—that latter mineral, when pure, being
commonly green, and its chemical analysis showing it to contain some
40 per cent. of magnesia. Thedield observer might therefore infer that
the colour was due to the magnesia it contained, but the chemist
could have informed him it was due to iron.
Again, we find (p. 518, Quart. Journ.), when alluding to the un-
altered strata, it is stated, “ In places they are parti-coloured, showing
yellow and green blotches owing to the decomposition of alkaline
matter with which the beds appear to be more or less charged.”
This paragraph may be understood by the author, but neither the
writer, nor several eminent chemists, before whom he has laid it,
can pretend to explain the peculiar chemical action alluded to in this
sentence, and as regards the assertion contained in the latter part of the
same, that all the beds appear to be more or less charged with alka-
-line matter, it may be stated at once, that the external appearance of
such rocks could not prove to any chemist, mineralogist, or geologist,
Origin of certain Granites, fc. 53
whosoever, either that the beds in question contained more or less
alkaline matter, or that they even contained any alkaline matter
whatsoever.
In the present state of science it is an utter impossibility, by any
means except careful chemical analysis (not to be performed by
unskilled hands), to determine the presence and amount of alkali
contained in rocks; and under these circumstances, geologists are
fairly entitled to require some explanation from the author, as to
whether such analysis had been made before expatiating so boldly as
he does, all throughout the papers, upon the alkaline nature of the
rocks described.
If such analysis had been made, the simple statement of the
results, what alkalies had been found present, and their percentages,
would, in itself, have been a valuable contribution to-science.'
In these memoirs no analyses of rocks are cited, and when such
expressions are found, as “they ought perhaps to be followed up by
analysis of the rocks,” and “ future chemical analysis will enable us
to clear up this point,” it is concluded that they were. not made, and,
in such case, statements appearing all throughout the memoir in the
Quart. Journ., as p. 516, “less alkaline;” p. 518, “no recognisable
amount of alkaline matter;” p. 519, ‘greenish alkaline felspathic
part ;” p, 521, “portions more highly alkaline than others ;” “alkaline
character of strata;” ‘‘admixture of alkaline matter;” p. 522,
“highly alkaline wacké;” ‘harder and more compact, (in other
words, less alkaline);”? p. 526, “insufficient supply of alkaline
matter ;” ‘whenever the strata begin to get alkaline, the altered
crystalline areas become amygdaloidal,” etc., are thoroughly unwar-
rantable.
As we know that many of the hardest minerals. and rocks in
nature contain no alkali whatever, it is difficult to imagine where the
author could get the notion that alkalinity was the cause of hardness.
in rocks, and it may be also asked, what he means, p. 526, “alterna-
tions of very highly basic, with less alkaline beds,” as if basicity
was dependant only on alkaline character.
In the same manner, the repeated. statements of the presence of
magnesia, if not confirmed by chemical analysis, but only given upon
the strength of the ‘“ greenness” observed in the rocks, cannot be
accepted by either chemist or mineralogist..
Much more might be written on the chemistry of these memoirs,
but, to avoid extending these remarks to too great a length, only one
more reference will be made.
In the communication to the Gronocican Magazine, p. 529,
Mr. James Geikie, alluding to his proofs and evidence, says,
“although to render them complete, they ought perhaps to be followed
up by analysis of the rocks.”
1 When it is remembered that a single accurate chemical analysis of such a rock,
which shows but a few lines in print, represents a value of, from five to ten. guineas in.
actual labour and expense to the chemist, it is easy to understand how, in general, so
much appears in print about the ideal composition of rocks,,and so. little verification.
of the same by actual chemical analysis.
4 The italics are sic in memoir,
B4 Forbes—On alleged Hydrothermal
‘The conviction on the writer’s mind is not only that the perhaps
‘should have been omitted, but also, that the analyses should have
preceded, and not followed, the enunciation of views which these
analyses, when made, may not improbably entirely annihilate.
How, may it be fairly asked, can any educated man, whether
geologist or not, be expected to believe that greywacké may be con-
verted into granite; unless, first of all, he is shown by chemical
analysis that you have present in the first, the chemical elements
requisite for the formation of the latter, or if not, that you have
a rational mode of explaining how any deficiency in component
parts has been supplied, or any surplus removed.
If such tangible data and explanations cannot be given, then all
like hypotheses must share the fate of the old alchemical visions of
transmutation, and it is but waste of time, thought, and energy to
place them before a rational public.
Supposing, for the sake of argument, however, that data are given
which showed that there was no obstacle, from a chemical point of
view, to believing that a certain bed of greywacké had been con-
verted into granite, then these very facts would be most conclusive
arguments against Mr. James Geikie’s assertion that this greywacké
had not only been converted into granite, but, also into diorite, ser-
pentine, porphyrite, etc., etc.; all rocks, differing essentially in che-
mical and mineralogical composition, not only from granite, but
from one another. ;
(2) Mineralogy.—Although the mineralogy of these memoirs will
be considered, chiefly in conjunction with the petrology, still some
points, purely mineralogical, require more definite explanation than
the author gives ; for example, with respect to felspar, on the study
of which so much of his results are based, is not the mineralogist
entitled to demand (seeing that this name is only a generic one,
including mineral species widely differing from one another in
chemical composition, as orthoclase, oligoclase, albite, anorthite,
labradorite, etc.) that the author should state what mineral he
-actually alludes to, or if not crystallographer enough to do so, at:
least state whether he writes of potash, soda, or lime felspars ; for
how else can any opinion be formed as to whether the species of
felspar is at hand which is characteristic of the rock which he
supposes is formed by his metamorphic agency. For example: sup- '
posing the felspar alluded to was a lime felspar, then the crystalline.
rock formed by the metamorphic action could not be a granite, for
, we know that lime felspar is never a normal constituent of any
granite.
At page 516, Quart. Journ., under the head of “‘ Amygdaloid,” it is
stated that “the matrix consists of a paste of felspathic matter, with ©
here and there a variable admixture of magnesia and lime.” Miner-:
alogists would find this somewhat difficult to explain, as native
lime is never found in the mineral kingdom, and native magnesia
only occurs in some active volcanoes, as the extremely rare mineral
-periklase,! so that neither of these substances are likely to have Born,
A hydrate of magnesia is also known as brucite,
Origin of certain Granites, §c.. a)
met with. If intended in a chemical sense, nothing short of actual
analysis could prove their presence.
Again (page 521, Quart. Journ.), the crystallographer will be
rather puzzled by the reference to “ Porphyritic Felspar Crystals.”
(3) Petrology.—In such an investigation as the present, it ought
to be superfluous to insist upon the most scrupulous care and atten-
tion being devoted to the petrological character and description of
the rocks forming the subject of the inquiry ; for how otherwise can
geologists know that they are referring to one and the same rock in
their inquiries ?
Here it is to be feared that the Geological Survey have not shown
an example worthy of imitation, when such names are used as
syenitic granite for hormblendic granite, augitic greenstone for
dolerite, greenstone porphyry for porphyritic greenstone, along with
granitic porphyry, syenitic porphyry, dioritic porphyry, trachytic
porphyry, felspar porphyry, syenitic greenstone, felspathic green-
stone, felspathic trap, etc., etc. ; and when upon examination in the
field, rocks coloured as greenstones on the map of the Survey fre-
quently turn out to be dolerites, felstones, altered clay slates, etc.,
whilst at the same time no explanations have been furnished by the
Survey, whether mineralogical or chemical, for the use, or rather
misuse, of such names.
Surely the petrologist may throw up his hands in despair when
he finds Mr. James Geikie defining minette as a quarizless granite ;
just as soon would he expect to see limestone defined as a clayless
marlstone, or as a calcareous sandstone without the sand. If the
mineral component which specially characterises granite, when com-
posed with all other analogous rocks, is to be left out, surely there
can be no sense in retaining the name of granite at all.
Such similes are unworthy of the geologist as tending to mislead
others less versed in petrology; for even if minette was proved to
have been formed from greywacke,' by hydrothermal or any other
action, such a fact does not value one iota in proving that it also
could be transmuted into granite, but the reverse.
At page 527, Quart. Journ., petrologists are told, “that under the
term dioritic are included all those rocks which consist essentially
of silicates of lime and magnesia set ina Felspathic base or matrix,” a
definition which no petrologist would for a moment admit, for then
he would have to regard as diorites, not only many porphyrites,
dolerites, &c., but also such true volcanic lavas of the present period
as are composed of a felspar with olivine, wollastonite, monticellite,
augite, ete.
The petrologist defines diorite to be a rock composed of one or
more felspars with hornblende, and regards greenstone as that
variety of diorite in which green or dark-coloured hornblende either
predominates, or, when the rock is fine grained, renders more
obscure the presence of the felspar.
What therefore a ‘“‘ granitoid diorite,” (referred to page 530, Guox.
1 A rock which, it must be remembereds consists essentially of seventy-five per cent.
of quartz. ae
»
06 Forbes—On alleged Hydrothermal
Maa.) may be, is difficult for a petrologist to understand, especially
since he is immediately informed that it “is simply an admixture of
hornblende with white and pink felspar,” and further told that it is
‘“‘of a more granitoid and less basic character than the usually finer
grained and often dull earthy rocks of dykes, which here and there
intersect the coal-measures ;” and, to complicate this confusion, in a
foot-note adds, “ most of the trap dykes of the Scottish carboniferous
strata, however, are not hornblendic, but augitic greenstones or
dolerites.”’
In investigations where exactitude is essential, trap is an ex-
tremely vague name to designate rocks by, as was long ago admitted,
for as early as 1827, Brongniart' says, ‘“C’est encore un trés mauvais
nom, etc,” and the term “felspathic traps” for one of their many
varieties of same is certainly not an improvement in the name of a
rock which, under all circumstances, is essentially felspathic, having
a felspathic base. The name trap, originally adopted from the
Swedish geologists, was understood to denote any compact dark-
coloured rock composed of felspar with augite.
The name wacké is another, which has but little true signification,
further than being usually applied to any dirty, indistinct mass, in
which the structure is obliterated; it is evidently, however, a
favourite with the author, who writes of “decomposing wackés,”
“calcareous wackés,” “altered wackés,” and “highly alkaline
wackeés,”’ etc.
Again the term porphyry, when applied to rocks, is frequently
improperly employed ; when used as an adjective, to imply a definite
structure, it is understandable, as porphyritic greenstone; but the
terms felstone porphyry, felspar porphyry or felspathic porphyry,
sound rather tautological. If the application of this term in petro-
logy, when used to designate a definite rock, is inquired into, it will
be found that it was originally used to denote such rocks as con-
sisted, like the true antique porphyry, of crystals of felspar set ina
paste of semicrystalline or amorphous felspar. It is therefore diffi-
cult to imagine a rock more felspathic than one composed mainly of
felspar, and one might just as well write of quartzitic quartzites as
“of felspathic porphyries ;” again, what is to be understood by
the term “ porphyritic felstones ” as different from porphyries ?
4, Geology.—It would be impossible to enter into an examination
of the geology of these memoirs without some local knowledge,
which the writer does not possess ; but before concluding he would
still enter his protest against some of the geological views put forth
by the author.
Thus, at page 517 and following of the memoirs read before the
Geological Society, great stress is laid upon the circumstance that, as,
instead of being flattened and drawn out, the vesicles found occur-
ring in these rocks are spherical, and are so over considerable areas,
the rocks therefore cannot be trappean or igneous; now surely,
any geologist acquainted with volcanic rocks knows that spherical is
1 Classification des Roches, p. 63.
Origin of certain Granites, ¢-c. 57
the invariable normal form of all such vesicles in lavas, etc., and that
the drawn out or elongated flattened form is a subsequent modifica-
tion assumed by the spherical vessels, either under the influence of
superincumbent pressure, or from the lava cooling more slowly, and
thus allowing the movement of the mass, when still in a viscid
condition, to draw out the spherical vesicles into somewhat of an
almond-like shape. Abundant instances, however, could be cited
where both lavas and traps also have retained their original spherical
shape over extensive areas, probably from their having cooled some-
what more quickly, or from having not had much motion communi-
cated to them under solidification.
Again, page 582 of the Guor. Mac., it is stated in a foot-note that
“Tt is certain, however, that rocks such as diallagite, hypersthenite,
diorite, syenite, and even granite itself can be developed directly
from aqueous rocks, etc.” This assertion appears to be put forth
solely upon the authority of Mr. James Geikie, for a careful examina-
tion of the literature of the subject in the English, French, German,
Spanish, Italian, Swedish, and. Danish languages, certainly does
not confirm it, and it is to be hoped that geologists will require
positive facts, and not vague hypotheses, before they accept such a
statement for granted.
The writer believes that in several cases, at least, where views
of this nature have been entertained, they have been formed by
persons not much acquainted with petrology or mineralogy, from
their confounding certain rocks with names which did not in reality
pertain to them. An example, illustrative of this, may be cited:
The writer of these remarks, finding from an examination of the
sheets of the Geological Survey that large masses of greenstone
were represented as occurring in Cornwall, near Penzance, and at
the Botallack mines, immediately imagined that he would there find
the same relations of this greenstone to the metallic lodes, occurring
as he had found to be the case in South and North America, Spain,
Norway, Sweden, etc., and made a journey expressly for this exami-
nation ; on arrival he at once found that the rocks had evidently
been metamorphosed in sit#, and they no doubt originally had only
been the ordinary sedimentary clay-slates. Had he now been content
with the decision of the Geological Survey that the rocks in question
really were greenstones, then he must at once have come to the con-
clusion that greenstones could be formed by the alteration of clay-
slates in sit#. It did not, however, require a long examination to
prove that the rocks were neither petrologically, mineralogically,
or chemically, greenstones, or even any allied rock, being nothing
more than clay slates altered in siti and possessing none of the pro-
perties of greenstones beyond the greenish tinge which coloured
them.
Geologists have been accustomed to define, as eruptive or in-
trusive rocks, such rocks as are met with apparently breaking
through, protruding into, or sending out ramifications, dykes, or
veins, into the adjacent stratified deposits.
Mr. James Geikie (p. 530, Gmou. Mag.) refuses any longer to
58 Forbes—On alleged Hydrothermal
accept this definition, and cautions geologists against accepting such,
as a test of the eruptive origin of such rocks.
The writer would state that his experience, both in the field
and out of it, confirms himin adhering to the old definition, and he
finds (in which he believes most geologists will concur with him)
no evidence in Mr, James Geikie’s memoirs to shake his confidence
im ib.
The writer of these remarks does not, in this communication,
even wish to express any opinion as to whether the views adopted.
by Mr. James Geikie are right or wrong; but leaves it to the geo-
logical reader, after perusing them, to decide for himself how far
the conclusions arrived at by that gentleman are entitled to confi-
dence. He would, however, wish it to be understood that in
bringing forward these remarks, he is not in any way influenced by
any feeling of personality against a gentleman whom he has never
even seen; and he may state that the substance of this communication
was put upon paper long before the papers here referred to appeared,
having been intended as an answer to similar views? elsewhere put.
forward, and based upon similar (in the writer’s opinion) unsound
data. The appearance of Mr. James Geikie’s memoirs, apparently
representing in some measure the views entertained by the Geological
Survey of Great Britain, decided the writer in at once protesting
against the nature of the evidence by which the opinions were
supported. No theoretical views can now expect to be accepted in
science without having had the evidence in their favour thoroughly
scrutinized and subjected to the cross-examination of the collateral
sciences, for times are much changed from what they were some
fifty years ago, when it was a common practice to explain effects,
apparently unaccountable, by referring them to the agency of
electricity, or some other then little understood cause, thereby.
finding a convenient solution for avoiding the labour of working out
abstruse problems; it is, however, to be hoped that geologists
* The writer takes the opportunity of here stating, that the results of a protracted
study of this subject (several of the details of which will be found in a series of
communications, which have appeared at intervals, since 1853, in the Magazin for
Naturvidenskab, Skandinaviske Naturforskeres Forhandlinger, Philosophical Maga-
zine, Quarterly Journal of the Geological Society, Edinburgh Philosophical Journal,
and other periodicals), have induced him to conclude :— ‘ t
- (1.) That when the geological epoch of the appearance of an eruptive or intrusive,
rock is known, such rock will be found to differ essentially, in mineral constitution,
from similar rocks injected at a different geological period.
(2.) That eruptive or intrusive rocks of identical mineral constitution, have made
their appearance or intrusion into the earth's crust at the same geological epochs.
(8.) That the minerals, or classes of minerals, accompanying or associated
with such intrusive or eruptive rocks, may serve as a means of distinguishing
the several eruptions in geological chronology, in a manner analogous to the deter-
mination of sedimentary strata, by the fossils, or classes of fossils, which they may be
found to contain. i
_ ? The views in question are far from being new, for under various dresses they ap-
peared, were discarded, and re-appeared from time to time, even from the infancy of
geology ; some of their advocates having even gone so far as to suppose that the state
of granite was one which all rocks would ultimately arrive at, after undergoing a pro-
cess of slow but constant internal alteration or fermentation, i pr op
Geol. Mag I867
JDintre! detet lith.,
CO CAEL OM ON is,
Vol IV. PUTV.
W West imap,
we)
WWest imp.
=|. et hth.
ike]
abat
J.D
COCHEIOD ONT S
Origin of certain Granites, gc. 59
will not now make a similar convenience of hydrothermalism, but
put their shoulders to the wheel, study hard at the collateral sciences,
and work out upon a sound basis the true parts which each different
agency has played in nature’s operations.
TIl.—On tor Manprsie anp Manpispunar Trets or CocHnioponts.
By Prorrssor Owen, F.R.S., F.G.S8., Ere. ©
[PLATES III. AND IV.]
HE extinct cartilaginous fishes represented in ‘mountain lime-
stone’ and similarly aged carboniferous formations by detached
teeth, or dental masses adapted for crushing, have been referred to the
Cestraciont family ; and, so far as I know, have now no nearer living
representative, in the class of fishes, than the Port Jackson shark
(Cestracion Philippi.)
The detached condition of the so-called ‘palates,’ indicates a
similar ligamentous attachment of the teeth to a cartilaginous jaw,
as in that genus, and the oblique course of their main elevations and
furrows (Plate II1., Fig. 1, e. g.) is repeated in the arrangement of
the series of smaller and more numerous crushing teeth of Cestra-
cion (‘ Paleontology,’ p. 127, Fig 41), so as to have suggested the
remark that ‘‘it would seem as if the several teeth of each oblique
row in Cestracion had been welded into a single dental mass in
Cochliodus, the proportions and direction of the rows being closely
analogous” (ib. p. 128).
Whether, however, the resemblance between the carboniferous and.
existing Australian conchivorous sharks was carried out in the form
of the jaws, and especially their forward prolongation with a rasp-
like arrangement thereon of pointed teeth for working down to, and
extracting from, their sandy beds and burrows, the shell-clad mol-
lusks and crustaceans, constituting the food of such fishes, I had
not been able satisfactorily to determine at the date of the above-
quoted paragraph (8vo. 2nd Hd. 1861).
I have since, however, been favoured by the Harl of Enniskillen
and the Rev. Professor Sedgwick with the opportunity of examining
some specimens that settle this point, and indicate that the extinct
crushing-sharks of the mountain limestone period, though instruc-
tively represented by a lingering member of a once numerous section
of Chondropteri, must be relegated to a distinct though conterminous
family, for which I propose the name Cochliodontida, from what may.
be regarded as the representative genus, Cochliodus Ag. (Pl. III).
‘the specimen, Figs. 1 and 2, of the dentary part of the mandible
with the teeth of each ramus, though somewhat mutilated as regards
both jaw and teeth, shows the confluence of the rami at a symphysis
which, in relative position to the teeth, would correspond with the
parts of the mandibular rami of Cestracion containing the anterior
crushing teeth. The fore-part of the symphysis itself is, indeed,
broken away; but its small vertical depth at the point of fracture,.
together with the small tranverse extent, and the angle at which the
rami converge thereto, afford no eround for assuming that the:
60 Owen—On the Teeth of Cochliodonts.
symphysis was prolonged, as in Cestracion, for the support of conical
or any other teeth. The absence of such conical teeth, detached, in
the matrix, had, indeed, led to the inference of their non-develop-
ment in the jaws of these mountain limestone fish. But the better-
preserved mandible of Tomodus convexus, Ag. 1859,' (Pl. IV. Figs.
2-5), leaves no doubt of the short-pointed edentulous termination of
the symphysis a little way anterior to the series of large molars or
crushing teeth. The resemblance of this mandible to that of the
similarly endowed jaw of the elephant, is interesting, as exemplify-
ing the adaptive relations of bone, sustaining and working dental’
masses like millstones in species of classes the most remote from
each other in the vertebrate series.
In the mandible of Cochliodus the teeth are, originally, three in
each ramus, and the primitive distinction sometimes remains longer
in the ‘ vasodentine,’ or osseous basis of the tooth, than in the ‘vitro-
dentine,’ or enamel covering of the tooth. The anterior tooth, 7b.
Fig. 1 a is the smallest, of a triangular form; its chief part formed
by the mid-lobe or ridge, a, which is very convex and obliquely and
gently contorted from behind and below, upward, inward, and
forward, with a slight increase of breadth or, fore-and-aft diameter,
in this course, and with the moderately convex inner or mesial
border in contact with that of the tooth of the opposite ramus.
.The anterior lobe seems to have had the form of a small tubercle,
but its summit is broken off; the posterior lobe is a narrow, seam-
like, raised border, extending farther back on the outer side, Fig.
2 a, than on the inner side of the ramus.
The middle tooth, (Pl. II, Figs. 1 and 2 6), is of greater transverse
than antero-posterior extent, and, like the foremost, consists
mainly of the second or mid-lobe: its crown is a longish triangle,
with the short base ‘ mesiad,’ and the obtuse apex laterad, or out-
ward. This, in the tooth of the right side, is shown in Fig. 2 6: as
it rises from this side or end the lobe is very prominent, but
it slightly subsides, as it expands and bends over the mandible to
the inner surface, where it is in contact for four-fifths of its extent
with the same surface of the opposite tooth, (Pl. III. Fig. 16). The
anterior lobe, very narrow at the outer side or apex of the tooth,
increases in antro-retral breadth to the inner side or base of the
triangle, but with scarcely any elevation. It makes, thus, part
of the border of the tooth slightly concave, as shown on jhe right
side, in Fig. 1. The posterior lobe, or ridge of this tooth, b, is
obsolete.
The third and largest tooth is that on which the genus and
1 Cochliodus magnus, Ag. 1835.
2 This structure of the teeth, recent and fossil, of Cestractonts and Cochhiodonts, was
microscopically determined and described in my Paper ‘On the Structure of Teeth,”
Reports of British Association, 1838, p. 135. ‘These teeth are composed of two
substances, viz., an external almost colourless layer, with a finely punctate surface,
which represents the enamel, and a coarser dentine composing the body of the tooth,
and continuous with and passing into its basis of support.””—J0. and Odontography,
p- 54. In the article ‘rznru,’ Cyclopedia of Anatomy, vol. iv. 1852, these dental
tissues are defined under the names ‘ yasodentine,’ and ‘ vitrodentine,’ p. 865.
Owen—On the Teeth of Cochliodonts. 61
species was originally founded, and is the most common among the
many detached ‘palates’ of the English mountain limestone lo-
calities. It is mutilated in both halves of the jaw; but I have
figured more entire specimens of this tooth, from the right ramus of
the lower jaw, (Pl. III. Fig. 5), and from the left ramus, (PI. II.
Fig. 4); which positions in the jaw, the specimen (Fig. 1) enables
one to determine, in detached teeth.
In this third or posterior grinder (Pl. IT], Fig. 1 c) the longitudinal
exceeds the transverse diameter, but the triangular form of the crown
prevails, the base now forming the longest side (Fig. 5,>**), and
the apex being more truncate than in the middle tooth. The apex,
or outer side of the third tooth, is shown at Fig. 2 c, or rather
the vasodentine supporting the apical part of the vitrodentine,
which is here very thin, and a small part of it is broken off in
the specimen. The mid-lobe, c, as it rises, bends inward and
slightly backward, maintaining its convexity as it expands, better
than in the tooth 6, and terminating, medially or internally, in a
gently convex thin border. In the detached homologues of this
tooth, from both sides of the jaw, the mid-lobes hows at its
inner half a surface worn more or less flat by trituration and
sloping from before, outward and backward. The reticulate surface
of the osteodentine often takes the place of the punctate surface of the
vitrodentine at the middle and toward the back part of this worn
surface, showing where the pressure and attrition was greatest from
the opposite upper crusher. ‘The anterior lobe of the third tooth, at
its apex or outer end, Fig. 2, is almost as broad from behind forward
as the middle lobe, but it gains in that diameter very slightly as it
curves over the tooth to the inner side, and it is very little elevated,
especially in the upper and inner surfaces; there is, however, some
variety in this respect, as in the detached tooth, Fig. 4, but not to a
degree which I am disposed to regard as specific. ‘The posterior lobe
(Figs. 4, 5°), of equal breadth with the middle one on the outer border
(Fig. 2 c), increases in antero-posterior extent, as it curves inward,
in a greater degree than does the anterior lobe, but in a less degree
than does the middle one ; it soon loses the slight degree of fore-
and-aft convexity, with which it began externally, and, from being
flat, becomes slightly concave on its inner and broader end. In
passing from without inward, the third lobe inclines more backward
than either of the preceding lobes, and the anterior lobe the least so,
the almost (antero-posteriorly) flattened surface on the third lobe
slightly rises toward its posterior border, which is smoothly rounded,
Fig. 4°.
The substance of the mandible supporting the teeth equals in
vertical extent that of the tooth it supports; it goes on increasing in
depth posteriorly for the extent to which it is preserved, but di-
minishes in breadth, indicating a shape of jaw like that in Cestracion.
The structure of the bone resembles that of the better ossified
parts of the chondrine of plagiostomous fishes.
The third tooth, right side, lower jaw, of Cochliodus (Pl. IV, Fig.
1) presents specific modifications of form, as compared with that of
62 Owen—On the Teeth of Cochliodonts.
‘Cochliodus contortus, Ag. (Pl. III, Figs. 1, 4, 5), as well as’ with
‘those of Cochliodus magnus, Ag. (now Tomodus) and Cochliodus
‘striatus, Ag. (now Xystrodus) ; it retains, however, the present
restricted generic characters of Cochliodus, and I indicate the species
under the name of Cochliodus compactus; the predominance of the
-middle (2) over the anterior (4) and posterior (3) lobes giving the
grinding surface of the tooth a more compact and simple character.
The specimen of the teeth in sité of Cochliodus contortus, Ag. (Pl.
III, Figs. 1 and 2,) is from the Carboniferous Limestone at Bristol,
and forms part of the collection of the Rev. Professor Sedgewick, at
Cambridge. .
In Plate III., Fig. 3, is figured a small portion of the mandible or
lower jaw, with the third tooth,-c., of the right side, and part of
that tooth of the left side, of Streblodus oblongus, Ag. The third lobe
forms a larger proportion of the tooth in this genus then in Cochlio-
dus and gives a greater proportionate length to the breadth of the
grinding surface of the entire tooth. The anterior lobe is repre-
sented by a mere seam. The middle lobe, commencing narrow, pro-
minent, and ridge-like, externally expands, and subsides to a moderate
convexity as it bends backward and inward over the jaw. ‘The
third lobe much more rapidly expands as it rises from the outer
‘apex to arch over the inner side, where it has a wavy margin, an inch
in extent, in a total length of grinding surface of one inch, seven
lines. The upper convex surface of this third lobe shows the chief
-area of attrition. The portion of the jaw preserved shows a large
and deep cavity within and behind the third tooth, which probably
‘lodged the matrix or germ of its successor. The symphysis of the
jaw was shorter and the rami met there at a more open angle in
Streblodus than in Oochliodus; the anterior ends of the last crushing
teeth came into contact at the back part of the symphysis. What
were the proportions of the homologues of a and 6 in Coehliodus
(fig. 1), or whether both or either were developed in Streblodus, the
mutilated outer or fore part of the symphysis, in this specimen, does
‘not permit to be determined.
The present specimen (PI. III. Fig. 3.), is from the mountain-
limestone of Armagh; and forms part of the collection of the Karl
of Enniskillen, at Florence Court, Ireland.
The most completely preserved specimen of the mandible of a
_Cochliodont is that of the Tomodus convexus (Pl. 1V. Figs. 2-5,) from
the carboniferous limestone of Bristol. Apparently the whole of the
dentary part of the right ramus and the anterior half of that of the
left ramus are here shown (Fig. 2). The posterior end of the right
dentary is of little breadth and depth, but it gains in both, and
‘chiefly in the latter dimension, as it approaches the symphysis, and
there rapidly acquires great breadth and thickness. The lower
border (Fig. 3), is thick and rounded ; the outer side, (Fig. 4) mode-
rately convex ; the inner side, (Fig. 5) somewhat wavy, being con-
cave lengthwise at its middle part. The hind part of the symphysis
extends back like a shelf (Fig. 2), from below the dentigerous surface
of that part of the mandible. . he Pe ae f
Morris— On Sarsen-stones. 63
- The first and second of the teeth meet above the symphysis, as in
Cochliodus ; the third pair are rather wider apart than in that genus.
The angle at which the two rami meet at the symphysis, is inter-
mediate between those that respectively characterise the mandibles
of Cochliodus and Streblodus.
The first tooth (Fig. 2, a) of Tomodus is relatively smaller to the
the others than in Cochliodus ; it is also more simple and conical in
form—so far it resembles more the anterior teeth in Cestracion, but the
apex is obtusely rounded. The second tooth has similar proportions
to those in Cochliodus, but the middle lobe is somewhat less convex,
and a posterior seam is better indicated. The third tooth (Fig. 2 c)
is longer from before backward, in proportion to its breadth, than in
Cochliodus, and it differs both from it and from Séreblodus, in the
lower and more general convexity of the grinding surface of the
last tooth. This surface has been crushed in the specimen here
figured, but will be illustrated, as also the teeth of Séireblodus, from
better preserved detached specimens, in a consecutive paper.
EXPLANATION OF PLATES III. & IV.
PLATE III.
Fig. 1. Upper view of dentary part of the mandible, and of the teeth of Cochliodus
contortus, Ag. From the Mountain Limestone of Bristol. Wood-
wardian Museum.
2. Outside view of right ramus of ditto; @. surface from which the right
anterior tooth has been detached; a’. corresponding tooth of left ramus;
b. right middle tooth ; 2’. part of left ditto; c. right posterior tooth, outer
margin of.
3. Posterior view of part of mandible and teeth of Streblodus oblongus, Ag.
From the Mountain-Limestone of Armagh. Museum of the Earl of Ennis-
killen.
4. Right third tooth of Cochliodus contortus, Ag.
5. Left third tooth of Cochliodus contortus. Both this and Fig. 4 are from the
Carboniferous Limestone, Bristol. Museum of the Earl of Enniskillen.
PLATE IVY.
Fig. 1. Right third tooth of Cochliodus compactus. From Carboniferous Limestone
of Yorkshire. Woodwardian Museum, Cambridge.
2. Upper view of mandible and teeth, Tomodus convexus, Ag.
3. Under view of ditto.
4, Outer side of right ramus of ditto.
5. Inner side of ditto. From the Carboniferous Limestone, Bristol. Museum
of the Earl of Enniskillen.
III.—On tae Occurrence or Gaey-WerTuers at Grays, Essex.
By Professor Joun Morris, F.G.S.
HE occurrence of “‘Sarsen-stones,” or blocks of so-called Druid
sandstone, has not, I believe, been generally noticed in this locality,
and their position may be of interest to some of your readers, more
especially as the extensive workings both for Brick-earth and Chalk
have obliterated many of the interesting sections for which the pits
were celebrated.’ Grays is well known both for its fine chalk-pits
‘and extensive brick-earth deposits, the latter containing numerous
1 Mag. Nat. Hist, 1836, p, 261; 1838, p, 539.
64 Morris—On Sarsen-stones.
remains of fossil mammalia, associated with land and freshwater
mollusca. The sarsen-stones (of which some may be still seen lying
about the large chalk-pit), I have noticed during the progress of the
workings as occurring on the upper surface of a bed of disturbed
chalk, above the solid chalk, and covered by a blackish or carbo-
naceous Clay containing freshwater shells. They are of various sizes,
some very large, and more or less waterworn, and may have been
originally derived from the boulder-clay. Their position was about
mid-way between the back of the present workings and the entrance
to the pit ; but little if any brick-earth has been worked here, and it
is probable that their position is equivalent to the base of the brick-
earth deposits in the adjacent eastern brick-fields. The northern
side of the great chalk quarry only exposes the eroded chalk and
green-coated flint bed, overlain by Thanet sands covered by false-
bedded sand and gravel and some brown clay. The brick-earth of
two of the adjacent pits is almost worked out, these pits presenting
only the obliquely-laminated sands and brown clays, which formerly
were seen to rest on the brick-earth below (sometimes, however,
separated by a thin bed of gravel), from which and its subordinate
beds all the interesting fossil remains were obtained ; the brick-earth
being separated from the subjacent chalk by a bed of gravel varying
in thickness in different parts of the area. The position of the brick-
earth, with its shell-beds (Cyrena, Paludina, Unio, etc.), is only
well seen now in the eastern field covered by the false bedded sands
above noticed, where, in the upper part of the same field, the Thanet
sands overlying the chalk may be observed.
The general section of these pits may be divided into two series,
the lower, or fossiliferous zone, comprising the gravel and overlying
brick-earth, in which both the mammalian and molluscan fauna
occurred, and the upper or unfossiliferous zone, comprising the
false-bedded sands and brown clays from which to my knowledge no
fossil remains have been obtained.
Whether both these appearances are mainly due to the same
agency, that of river action, may be considered doubtful. That the
formation of the lower zone is evidently so, is proved by the nature
of the remains embedded in it, while the false-bedded character of
the upper sands affords evidence of a constant change, not only in
the direction of the currents, but in the nature of the material
deposited and the absence of any organic remains. The uppermost
bed is again different, and may have been the result of other agencies
than those which formed the preceding subjacent strata. Generally
speaking, the deposit at Grays may be mainly due to the action of a
river flowing through a valley, which it has partly excavated, in the
lower tertiary and upper chalk beds, and most probably posterior to
the boulder-clay period.
Nore.—A paper by Lieut.-Col. W. T. Nicolls, entitled “‘ Remarks on some
‘Sarsens’ or Erratic Blocks of Stone, found in the Gravel in the neighbourhood of
Southampton, Hampshire” (with a plate), appeared in the GroLoaicaL Macazinx,
for July, 1866. Vol III., p. 296.—Zait. ;
&NHanhart imp
M
\de.lith,ad nat
1
De W:
5)
fed
WO
HORRIDU
Chalk Mart, Folkestone .
ACANTHOPHOLIS
Huxley—On a new Reptile from the Chalk-marl. <; 65
TV.—On Acawraopnoris Horerpus, A New REPTILE FROM THE
CHALK-MARL.
By Tuomas H. Huxtey, F.R.S., V.P.GS.,
Professor of Natural History in the Royal School of Mines.
PLATE V.
OME time since, my colleague, Dr. Percy, purchased from Mr.
Griffiths, of Folkestone, and sent to me, certain fossils from the
Chalk-marl near that town, which appeared to possess unusual
characters. On examining them I found that they were large scutes
and spines entering into the dermal armour of what, I did not doubt,
was a large reptile allied to Scelidosaurus, Hyleosaurus, and Pola-
canthus. 1 therefore requested Mr. Griffiths to procure for me every
fragment of the skeleton which he could procure from the somewhat
inconvenient locality (between tide-marks) in which the remains had
been found, and J eventually succeeded in obtaining three teeth, with a
number of fragments of vertebre, part of the skull and limb-bones,
besides a large additional quantity of scutes. J am still not without
hope of recovering other parts of the skeleton; but as the remains
in my hands are sufficient to enable me to form a tolerably clear
notion of the animal’s structure, a brief notice of its main features
will probably interest the readers of the Gzonocican Magazine.
The dermal bony plates or scutes (Plate V. Figs. 1-3) are of very
various forms and sizes, from oval disks slightly raised in the middle,
and hardly more than an inch in diameter, up to such great spines as
that represented in Plate V. Fig. 1, which could have fallen little short
of nine inches in length and five inches in the antero-posterior mea-
surement of its base. The outer surface of all these scutes is irre-
gularly pitted and, in the case of the long spines, is occasionally
marked by branching grooves which doubtless lodged vessels.
Each scute is excavated on its attached face in proportion to the
elevation of its outer surface, so that a transverse section of one of
the depressed scutes is more or less roof-like, while that of one of the
long spines shows it to possess a great internal cavity like the -
medullary cavity of an ordinary bone.
Some of the scutes, though comparatively few, are almost flat,
with an obtuse median ridge, which is highest about the middle of
the scute (Plate V. Fig. 3). But when the ridge is more prominent,
as in Plate V. Fig. 2, its summit is usually placed very much nearer
one edge than the other, so that one side of the triangular lateral
aspect is much shorter and more perpendicular than the other.
The short side, however, is not absolutely perpendicular in any
scute among those which have reached me, and the summit con-
sequently always lies within the circumference and never overhangs
it.
The spine-like dermal plates are altogether unsymmetrical. If,
as I suppose, the convex edge of that represented in Plate V. fig. 1
was anterior, then the posterior edge is concave, and the left side convex,
with a slight longitudinal excavation in its anterior half; while the
VOL, IV.—NO, XXXII, 5
66 Huzxley—On a new Reptile from the Chalk-marl.
right side is much more deeply hollowed in the same direction.
Furthermore, the anterior, convex, edgeis not straight, but is slightly
concave towards the left, and convex towards the right side ; while
the posterior, concave, edge is concave towards the right, and convex
towards the left side. The ridge which forms the posterior edge is
suddenly interrupted near the base of the spine by a deep notch,
(Fig. 1, a,) which probably received the anterior edge of the next
succeeding spine. The transverse diameter of the base of this spine
could not have been less than four inches when it was entire.
I estimate that the more or less complete remains of nearly a
hundred scutes of the different forms now mentioned, must have
passed through my hands, and, as they all came from one small
area, they probably belonged to one animal.
Such vertebrae as have been obtained, are in a very fragmentary
state. The body of a dorsal vertebra is about 1:5 in. high, but
has a less width; its length cannot have exceeded two inches. Its
articular ends are very slightly concave, and it is somewhat narrower
in the middle than at the ends. The neural canal is spacious,
being not less than one inch high. The neural spine appears to have
been low and inclined somewhat backwards. Another detached body
of a dorsal vertebra is 2:1 in. long, 0-2 in. high, 1:85 in. wide at its
articular ends, and 1:5 wide in its centre. The sacrum of this
reptile would be very interesting, but no fragment of that part of its
skeleton has as yet made its appearance. Of the skull I possess
only a very much mutilated fragment, showing the basioccipital and
basisphenoid. The occipital condyle measures 1:4 transversely, or
has about the same diameter as that of the skull of a Crocodilus
biporcatus, which measures 16 inches in length, from snout to
occiput. But it is more elongated transversely and excavated above
than in the Crocodile, and the exoccipitals enter more largely into
its composition. The Crocodilian disposition of the Eustachian tubes
is absent, and the carotids run up the side of the basisphenoid in
Lacertilian fashion. The sslla turcica has a well developed posterior
late.
i Only three teeth have been found in connexion with these remains,
but one of them is in a very perfect state, and was readily detached
from the matrix, so as to be easily viewed from all sides, (Plate V.
Fig. 4, a, 6, c). ‘ The crown is broken off from the fang, which
another specimen shows to be about as long as the crown and sub-
cylindrical. The crown is nearly 0-4 long, the greater diameter of
its base is 0:27, and the less about 0:2 ; itis shaped like a lance-head,
with an acute point and sharp edges; these edges are notched in
such a manner that the crown exhibits eight serrations on each side
of its apex. The enlargement of the crown into its swollen base is
somewhat sudden, and takes place higher up on the one face of the
tooth than in the other, so that when the tooth is viewed from one
edge the one face appears concave and the other convex (Plate V.
Fig. 4, 6).
The most curious feature about this tooth, however, is its colour.
The ground hue of the crown is pale brown, but vertical lines of dark
Hualey—On a new Reptile from the Chatk-marl. 67
chocolate colour run vertically and parallel to one another from the
serrated edge to the swollen base, on which they die out. The
middle of each intermediate pale brown band exhibits a very
delicate dark line.
One of these pale brown bands occupies the middle of each face of
the tooth and its apex. On each side of this are six or seven dark
bands and as many interspaces. The dark bands correspond pretty
nearly, but not exactly, with the summits of the serrations.
The shape of these teeth is quite different from that of the teeth
of Scelidosaurus, which they approach most nearly.
The most perfect fragment of any of the bones of the extremities
appears to be the distal end of a humerus. [It presents a division
into two condyles by wide and shallow anterior and posterior de-
pressions, and the width of the bone in this part, when perfect, could
hardly have been less than five inches. It narrows very rapidly,
however, and where it is broken, at 3°5 in. from the dorsal end, its
shaft is not more than 1:7 in. wide and as much in antero-posterior
diameter. It has a large medullary cavity, the bony walls of which
are on the average not more than 0:3 in. thick.
From the general resemblance of the dermal armour and teeth of
this reptile to those of Scelidosaurus, Hyleosaurus, and Polacanthus,
it plainly belongs to the same group ; but its teeth separate it from
the first genus, and the characters of its dermal armour from the two
latter. I propose to call it Acanthopholis horridus.
My colleague Mr. Etheridge is good enough to supply me with
the following precise determination of the stratigraphical position of
the remains. I may add that numerous portions of Ichthyosaurus
campylodon have been obtained by Mr. Griffiths ‘about six feet lower
down ” than Acanthopholis.
EXPLANATION OF PLATE V.
Acanthopholis horridus, Huxley.
Fig. 1. a. Side view of one of the spine-like scutes: 6. Front view of the same.
Fig. 2. a. A more depressed scute seen from above; b. viewed laterally; ¢. viewed
from the hinder, or more raised, end.
Fig. 3. a. A still flatter scute seen from above; &. viewed laterally ; c. viewed from
the hinder end.
(The preceding figures are one-half the size by nature.)
Fig. 4. a. A tooth viewed from one side; 4. with one edge turned to the eye; c. from
above.—The outlines give the natural size of the tooth.
V.—On THE STRATIGRAPHICAL Posrrion oF ACANTHOPHOLIS
HORRIDUS (Huxley).
By Rozrt. Ernerince, Paleontologist to the Geological Survey of Great Britain.
TJ)ROFESSOR HUXLEY’S communication, relative to the dis-
covery of a new Reptile in the Lower Chalk of the south of
England, which he has called Acanthopholis horridus, may be rendered
more interesting by a detailed description of its stratigraphical posi-
tion and its associated organic remains, a matter of some importance
in this case, as few, if any, higher reptilian remains have occurred
68 Etheridge—Stratigraphical position
in the Lower Chalk of either Europe or England; whereas in the
Wealden group below the true Cretaceous rocks, and still lower, in
the Oolites and Lias, many genera occur. The discovery by the
Rev. W. Fox of a remarkable and allied reptile in 1866, from the
Wealden beds of the Isle of Wight, named Polacanthus by Pro-
fessor Owen, increases still more the interest of this new genus,
and is another reason why it is well to understand its geological
horizon.
The remains were found in the autumn of the past year in the
lower part of the Chalk Marl immediately east of Copt Point, Folke-
stone. The beds of the Lower Chalk here are much disturbed and
pushed out of place, owing, doubtless, to the unctuous nature of the
Gault which underlies the sandy Upper Greensand; and the Lower
Hard Chalk, owing to its great superincumbent weight, has slid
over and here pressed up the Gault and Upper Greensand seaward,
thus giving a faulted appearance along a line from east to west ; it is,
however, superincumbent pressure only that has produced the
crumpling and apparently reversed dip of the Gault, Upper Green-
sand, and the lower members of the Chalk. The true position of
the whole series is admirably exhibited and easily understood along
the shore to the eastward under Lyddon’s Spout, ete.
The sequence of the beds near Copt Point, where the Reptilian
remains were found, was at first difficult clearly to understand, from
the circumstance of their occurring between high and low water
mark, and the denuding agency of the sea, along the strike, or
exposed edges of the beds which dip north, or towards the cliff, is
constantly destroying the soft Upper Greensand and yielding Lower
Chalk. :
I was, however, enabled clearly to determine the true place of the
fossil, and also its associated fauna. From the same bed I listed no
less than forty species, comprising Amorphozoa, Echinodermata, Mol-
lusca, and the remains of another reptile, Ichthyosaurus campylodon.
At Copt Point the Gault may be about 100 feet in thickness, pre-
ceded by (when moist) the dark-green sandy Upper Greensand, which
is from fifteen to twenty feet thick, and at the upper part cuts
a bright copper-green colour. This Upper Greensand is immedi-
ately succeeded by the hard, dense, pale-grey Chalk Marl, which
becomes nearly white when deprived of its moisture. It was in the
lower part of this, and about eight feet above the Upper Greensand,
that the remains of Acanthopholis horridus were found by Mr. Griffiths,
portions of which ultimately came into Professor Huxley’s posses-
sion through Dr. Percy: their affinities were immediately recognised,
but the characters being different to any known genus no pains were
spared to obtain as much as possible of the remaining skeleton, and, ~
although in a fragmentary state, yet enough has been obtained to
establish the genus.
‘My attention, on visiting the section, was immediately turned to
the associated fossils, which clearly determine the age and position
of the remains, and definitely fix it as belonging to the lower part
of the Grey Chalk series, (the Chalk Marl with Brachiolithes) and the
of Acanthopholis horridus. 69
remains of Ichthyosaurus campylodon and Saurocephalus lanciformis
occurred in the same bed, numerous teeth of both genera being
found. Many well-marked species of Cephalopoda, peculiar to this
lower zone of the Chalk Marl, occur in the same matrix, viz.,
Ammonites Rothomagensis, Brong.; Am. navicularis, Mant Am.
Mantelli, Sow.; and Am. varians, Sow.; which last species has a
wider range in time and space than the other three. The nonin-
voluted sinistral Ammonitide, represented by Turrilites costatus, Lam. ;
T. tuberculatus, D’Orb.; T. undulatus, Sow. (Scheuchzerianus Bosc.); and
Scaphites equalis, occur plentifully, accompanied by Nautilus elegans,
Sow. and N. pseudoelegans, D’Orb; Terebratulina striata, Schloth.
(rigida, Sow.), Terebratula biplicata, Broch.; T. obesa, Sow., were
the only species noticed as coming from that particular horizon,
Pleurotomaria perspectiva, Mant.; P. rhodani, Brong., the latter
peculiar to the Lower Chalk, occurs but sparingly, and chiefly
in the form of casts. The associated bivalves of the group Asiphonida,
are Ostrea carinata, Sow.; Plicatula inflata, Sow.; P. pectinoides, Sow. ;
Tnoceramus mytiloides, Mant.; Exogyra, Pecten orbicularis, Sow., and
casts of other species; and only one genus of the Siphonida, viz.,
Pholadomya decussata, was observed amongst them. Of the Hehio-
dermata fragments of Goniaster Coombii or G. mosaicus, Forbes; Pel-
tastes clathrata, Ag.; P. umbrella, Aq.; Discoidea subucula, Klein ;
Holaster subglobosus, Leske; Pseudodiadema (Diadema) resembling
variolare, but eroded; and an Hemiaster; also club-shaped spines of
Cidaris. All these species occur in the Chalk Marl along the
shore, and are obtainable from fallen masses. Several Amorphozoa,
such as Chenendopora fungiformis, Brachiolithes labrosus, and another
species, are plentiful in places. This singular genus of Ventriculites
forms the chief mass of the lower part of the bed in which the Rep-
tilian remains occur. Vermicularia is the only annelide noticed. .
The above organic remains were found associated with Acantho-
pholis in the same matrix, and they tend not only to elucidate the
contemporaneous or co-existing fauna, but also to give exactness to the
determination of its age. Whether the habits of Acanthopholis
resembled the Scelidosawrus of the Lias, or the Hyleosaurus, and
Iguanodon of the Wealden, future research may more definitely
determine. We cannot, however, fail to ‘notice that in this new
form another link is added to the persistency of type preserved
through so long a period of time, and through those numerous
geological changes which occurred during the deposition and
succession of the lower, middle, and upper oolitic rocks, as well
as the Wealden and Cretaceous formations. It is to be regretted
that the skeleton should have been so dismembered, but the
unyielding nature of the matrix, which is tough, much jointed,
and possesses that conchoidal fracture peculiar to hard marly de-
posits, rendered it almost impossible to remove it in any other way
than piece by piece, and it was so incorporated with the remains,
that none but an experienced workman could have succeeded in
relieving even so much as is preserved to us.
70 Carruthers—On Graptolites.
VI.—Nore on tHe Systematic Posrrion or GRAPTOLITES, AND ON
THEIR SUPPOSED OVARIAN VESICLES.
| By Wm. Carrutuers, F.L.S.
ae observations which can throw light on the systematic
position of the Graptolitide are of great importance. That
these anomalous fossils are Zoophytes, in the wide sense of the term, is
almost universally conceded ; the difficulty is in determining whether
they are ccelenterate or molluscoid. Those who have described the
members of the family have almost invariably considered them to be
hydrozoa, and it must be allowed that in general aspect they very
much resemble Plumularia and Sertularia. But when their structure
is examined it will be found that they widely differ from any known
hydrozoon, and especially in that the entire polypidom is composed
of the different polype-cells, without any distinct common canal.
Sometimes the polypes rise from a common substance which extends
along the whole of the celluliferous portion of the organism, but
there is no constriction or septum at the. base of the cells, cutting off
this common substance from the individual polypes. This is the
structure of Graptoiitus priodon, Bronn. In other species the walls
of each cell seem to be continued to the solid axis, aS is the case
most probably in Graptolitus sagittarius, Lu. and certainly in some of
the species with a double series of cells, as Diplograpsus folium, His.
D. pristis, His. and D. cometa, Gein. The mouths of the cells are
frequently furnished with one or more long spines, as in some species
of Rastrites, and in Diplograpsus pristis, His. In these characters
the graptolites show a greater affinity with the polyzoa. Compare
the genera Seruparia and Bicellaria. But there are some peculiarities
which do not well agree with the living forms of either section of
zoophytes. Among these may be mentioned first the prolongation
of the solid axis in both the unilateral and bilateral forms beyond
the celluliferous portion in the newer ‘part of the polypidom, and
then their free polypidoms, for neither the spines which terminate
the older portion of some species of Diplograpsus nor the slender
base of Dendrograptus linearis, Car., could be radicles, and the species
of the genus Graptolitus have no indications of a hydrorhiza from
the older extremity.
Any information as to the method of reproduction would greatly
assist in forming an estimate of their affinities. In the November
number of this journal (Vol. III. p. 488), Mr. H. A. Nicholson drew
attention to some minute organisms from the graptolite shales of
Moffat, which he supposes to be the ovarian vesicles of Graptolites.
I have in my collection two or three distinct forms of these capsules,
and I have considered (perhaps wrongly) the fossils figured by Mr. W.
H. Baily in the explanation to sheet 138 of the Irish Survey, p. 12,
asanother form. Thinking they might be ovi-sacs, I have for many
years been carefully looking out in my quarryings in the Moffat
shales for any indication of the connection between the organisms
and the graptolites. In shales where every fossil is almost always
compressed to a mere film, and the remains are confusedly scattered
Carruthers—On Graptolites. 7
over the surface of the lamine, mere juxtaposition, without a trace-
able union, is of little importance. I believe the specimen figured
by Mr. Nicholson, which was the only one he observed, is a case of
mere juxta-position. If we are to be guided in our interpretation of
these organisms by the structure and relation of parts in recent
forms, it will be difficult to find an ovarian vesicle attached by a
large mouth to the polypidom, or having the relation to two cells
which is shown in Plate XVII. Fig. 3 (l.c.), and we do not know any
hydrozoon which has “corneous ‘gonophores’”’ that become “free
swimming ‘zooids.’”” Supposing the minute fossils to be ovarian
vesicles, we would be inclined to consider the elongated mucro to
be the pedicel. The broad end is always very faint, indicating that
the wall of the capsule was thinner at this place. Indeed the fossil
remarkably resembles the gonophore of Sertularia operculata, L.
except in the great difference in size. If it belonged to the grapto-
lite, we should expect a similar relation to the supporting organism.
In Sertularia the ovi-sac has a very simple structure. In the allied
genus Plumularia the sac is composed of the polype-calls of a branch
specially altered for this purpose, as was shown by Edward Forbes.
It consequently occupies the position of the branch, but in Sertu-
laria the sac rises from the surface of the common canal and does
not interfere with the symmetry of the parts. I have never been
able to detect in any graptolite the suppression of a cell, far less of
a series of them, that would indicate their possessing a vesicle
having the structure of those of Plumularia, nor have I seen on the
polypidom of the fossil any scars that could have been produced by
the fall of the capsule. The organisms that Hall found on a species
of Diplograpsus have a very different aspect from those found at
Moffat. He believes that the contents of the ovi-sacs were minute
graptolites like the parent. He figures a small specimen very near
to the mouth of a sac, from which he considers it has just escaped.
This also would be anomalous in hydrozoa. In the volume of the
Proceedings of the Royal Physical Society of Edinburgh, published
in 1858, I figured a young specimen of my Diplograpsus tricornis,
which seems to be the same species as that subsequently figured
by Hall under the name of G. Whitfieldiii I have traced its
growth from the youngest condition where the three spines were
at the proximal end, and the slender solid axis at the distal, and
only a delicate membrane expanded between without indication
of cells. As the organism grew the cells appeared, and gradually
developed around the free portion of the axis. I have noticed a
similar growth in D. pristis, His., and I believe also in D. cometa,
Gein., a beautiful species not uncommon in the Moffat shales. It
would be an important observation if anything like these younger
forms could be detected in the interior of a capsule, but in the
hundreds I have examined I have seen no indication of their
contents ; and in the innumerable specimens of double graptolites
which my hammer has laid open, I have never seen anything like
what Hall has figured.
The oval or rounded bodies which Mr. Nicholson figures are most
72 Fossil Fish of the Lebanon.
probably specimens of Siphonotreta micula which occur in these grapto-
litic shales. His description and figures, as far as they go, cor-
respond with M‘Ooy’s fossil, which I have found at Garple and
elsewhere in Dumfriesshire.
IN| Qs Saas) | Caer) Neer ie @ sient oe
————_
I.—Tae Fossin Fise or Mount Lesanon.!
HE fossil fishes of Mount Lebanon appear to have been first
noticed in the time of the Crusaders, and subsequently by the
travellers Korte, Lebrun, Volney, and mentioned by Scheuchzer, in
1708. They were first scientifically described by Blainville, who
noticed two species, and afterwards by Agassiz, Sir Philip Egerton,
Heckel, and Pictet. New researches on these fishes by MM.
Humbert and Pictet have been published at Geneva, illustrated by
19 plates. By these authors the fishes are considered to belong to the
Cretaceous period, from the great number of Teleostean fish and the
absence of Ganoids,—from a certain number of genera or groups which
exclusively characterize the Cretaceous period—from the great number
of extinct genera which give a special physiognomy to these faunas,
such as at Hakel, the Pseudoberyx, Petalopteryx, Coccodus, Aspido-
pleurus, and Cyclobatis, and at Sahel Alma, the Pycnosterinx, Cheiro-
thrix, Rhinellus, and Spaniodon, and lastly, from the fact that the
genera which have living representatives are the most abundant at
Lebanon, such as the types of the Beryx, the Clupea, and Chiro-
centrites, which are more or less eminently Cretaceous, or have their
commencement in that period.
From a general comparison of the fish fauna of Hakel with that
of Comen in Istria,—of the fauna of Sahel Alma with that of the
Westphalian Chalk, and both of them with the Cretaceous fauna of
England, the authors consider that the fishes of Lebanon belong to
the Middle Cretaceous period.
In reviewing this fauna paleontologically, or in relation to the
previous Jurassic and subsequent Tertiary periods, some interesting
facts appear. Taking the classification of fishes by J. Muller, but
three of his sub-classes have fossil representatives, the Hlasmo-
branchs, Ganoids, and Teleosteans. The latter being generally
considered to have first appeared in the Cretaceous period, but the
genera Tharsis, Leptolepis, etc., are now recognised as Teleosteans,
and related to the Halecoides,—fishes which possess in a high degree
the normal characters of the class, and of which they represent
somewhat the archetype. The Hlasmobranchs are not abundant
at Lebanon, the principal forms belong to sharks and rays. The
Ganoids are not represented in this fauna, for the Hoplopleurides are
not true Ganoids. The third sub-class, the Teleosteans, are the most
important, and constitute nearly the whole of this fauna. Of this
sub-class, the Helecoides contain nineteen out of fifty-one species ;
1 Nouvelles recherches sur les Poissons fossiles de Mont Liban, par MM. F. J.
Pictet et A. Humbert, Geneva, 1866.
Coal Discoveries in Canada. 73
next in importance are the Ctenoids. The fish with pectinated scales
present four types respectively, represented by the group of the
Beryx, the Pseudoberyx, the Pycnosterinx, and Platax. These four
types, very distinct at the present day, are found at their first
appearance to have some characters in common, which become
diminished or effaced in succeeding periods, so that they represent
the base of four divergent rays, between which are intercalated all
the families which have not existed before the Cretaceous epoch.
Other Teleosteans, but much more rare, are also found at Lebanon,
such as one or two Sparoides, one or two Grobioides, and a curious
genus, Petalopteryx; and lastly, the Hoplopleurides, characterized by
a series of scales arranged in longitudinal rows, form a group which
at present are special to the Cretaceous period. Thus the fauna of
Lebanon, like other Cretaceous faunas, presents relations to succeed-
ing and scarcely any to preceding ones ; the general character being
the great diminution of Ganoid, and their replacement by many
Teleostean fishes.—J. M. .
1I.—Coat Discovertzs, anpD Primorprat Fossris, In Nova Scorta,
AND NEw Brunswick.
[Extract of a letter from Principal Dawson, F.R.S., ete.]
HILE your attention in England is much occupied with
questions as to the character of your coal-fields, ours in
British America is excited by the constantly recurring discoveries of
new and greater deposits, almost beyond our present power to utilise
them. The great coal-seam of Pictou, thirty-eight feet in thickness,
and accompanied by three other workable beds, having an aggregate
thickness of nearly as much more, has long been known ; but, until
recently, its horizontal extent had been proved only over a very
limited area. Within the past three years, an extension of these
great beds, with only slightly diminished thickness, has been proved
over five other properties, which must contain an aggregate workable
quantity of at least one hundred and fifty millions of tons of good
bitumimous coal, and there are the best reasons for believing that a
much greater extension of these beds will yet be found. The
capabilities of our other coal-fields in Nova Scotia and Cape Breton,
are also almost daily receiving new illustrations, by the opening up
of additional coal areas. Some of the new mines are being worked
by companies in Nova Scotia or in Canada, but the greater part by
companies in the United States. It seems strange that these deposits,
near the coast, within ten days of England, and in a country where
the means of subsistence are cheap, should not attract, to a greater
extent, the attention of English capitalists, with the view of making
them a means of extending British mining and manufacturing in-
dustry.
Little notice appears to have been taken in England of the very
remarkable discovery, by Messrs. Matthew and Hartt, referred to in
Prof. Bailey’s Report, on Southern New Brunswick, and also in a
paper by Mr. Matthew, in the Journal of the Geological Society, of
74 Coal Discoveries in Canada.
a primordial fauna, equivalent to Barrande’s “‘ Etage C.,” and to the
English Lingula flags, in the slates of the vicinity of St. John, New
Brunswick. Mr. Billings has recently examined a suite of these
fossils, and perfectly agrees with Mr. Hartt, as to their age, which in
his opinion will place them below the Potsdam Sandstone, and on the
horizon of Salter’s Menevian, and will bring for the first time into
their true geological position the older slate series of Nova Scotia,
Newfoundland, and New England. Mr. Hartt hopes soon to publish
descriptions of these fossils, including no less than five species of
Paradowides, and seven of Conocephalites,
These and other important new facts, I shall endeavour to apply
to the elucidation of the geology of the Eastern part of British
America, in the new edition of my “Acadian Geology,” now preparing
for the press.
I1].—Coat or Pictou, Nova Scorta.
YHE coal-field above alluded to, now proposed to be worked, is
called the Bear Creek Mine, and is considered by Dr. Dawson
and Mr. Robb to be a continuation of the same coal seams as those
opened out in the adjacent district, and known as the Albion and
Acadian mines. The Pictou coal-field presents peculiar and excep-
tional characters, as well as local complexities of structure, which
Mr. Robb considers to be due, first, “to the existence of folds or
flexures in the older rocks previous to the deposition of the Coal-
measures; causing irregularities of surface, which by determining
the direction and intensity of currents, would produce a great diver-
sity in the thickness and quality of the beds. And secondly, to the
continuance of the same elevatory forces which have originated the
folds, subsequently to the filling up of the troughs ; and producing in
the Coal-measures themselves a series of anticlinal and synclinal
folds, with dips varying in direction according to the original trend
of the rocks; and in amount according to the sharpness of the folds.”
The Bear Creek mine comprises about 1080 acres, and has been
found to contain four coal seams, the thickest being 19 feet, these
beds, according to Mr. Robb, being identical with the Deep, Main,
and McGregor seams of the Albion mines. The lowest seam or
Frazer oil coal of those mines, yielding on distillation 200 gallons
of crude oil per ton, has not yet been discovered at Bear Creek, but
there is scarcely any doubt that it exists there. The aggregate amount
of coal contained in the four seams discovered is estimated at 24
million tons, allowing for every deduction. .
TV.—On tue Discovery or Fossir Human Remarns in THE LEH
OF THE VALLEY OF THE Raine AT HevisHErm, NEAR Commar. By
M. Faupe..
HE Lehm in which these human bones were found occupies the
same stratigraphical position as the Lehm of Alsace, forming
the upper part of the “‘Diluvial Beds.” It is a marly deposit, of a
*
Human Remains in the Lehm. 7p:
yellowish-grey colour, composed of a mixture of clay, fine sand, and
carbonate of lime. It contains in abundance those calcareous con-
eretions called ‘‘Kupstein,” or “ Puppelestein” (“pierres en forme
de petites poupées’’), and has yielded also three characteristic shells :
Belle hispida, Linn.; Pupa muscorum, Drap.; and Succinea oblonga,
rap.
Bones of a large stag (species undetermined), including an almost
entire frontal bone measuring 18 centimetres transversely between
the horns, were exhumed.
A fine molar tooth of Elephas primigenius, and a metatarsal bone
of Bos priscus were found at the base of the deposit.
All the bones have completely lost their organic matter ; their
texture is chalky, they are of a white colour, and very fragile.
The human bones consist of a frontal and a right parietal bone,
almost entire. They belong to the same skull, and of an adult
individual of middle stature. They were found together embedded
in the Lehm, and present the same white colour as the other bones,
and must have undergone identical alterations in texture and com-
position.
The author’s chief conclusions are that man lived in the valley of
the Rhine contemporaneous with the fossil stag, bison, and mam-
moth, and that the appearance of man in the country would have
been previous to certain movements of the earth, which took place
after the deposition of the ‘diluvium,” and which have given the
ground its present physical configuration.—Comprrs ReEnbus.
REVIEWS.
I.—QUARTERLY JOURNAL oF ScreNcE. No. 18, January, 1867.
EVERAL articles of general interest are contained in this Journal.
The first, entitled, “Si Charles Lyell, and Modern Geology,”
accompanied with a lithographic portrait, sets forth the claims of
that philosopher to be considered as the “founder of Modern
Geology,” in the sense of his being the man who first clearly defined
the principles of geological investigation, and is a review of his more
popular works. The article is written in a clear, sound, and. philo-
sophical manner, and forms an essay on the progress of Geology,
as well as an autobiographical sketch of its modern historian.
A second paper is on “the Ignigenous Rocks, near Montbrison,” by
Dr. Daubeny, a supplement to his previous paper (see Grou. Mac.
Vol. III. p. 216) on the Antiquity of the Volcanos of Auvergne. The
only igneous rocks observed in the neighbourhood of Montbrison con-
sist of a compact basalt, with nests of olivine, a material which could
only have been elaborated by the aid of great pressure, and under a
different configuration of the surface from that now existing, and
the author concludes that a vast antiquity must be assigned to these
basalts.
Mr. A. R. Wallace contributes an article on “ Ice-marks in North
Wales,” a review of Glacial Theories and Controversies; and Mr.
76 - Kenrews—L’ Homme Fossile en Europe.
Hull a paper “on the future Water-supply of London,” with an account
of the two great schemes for obtaining it, one of which was pro-
pounded by Mr. Bateman, and applies to North Wales, the other by
Messrs. Hemans and Hassard, to the Lake-country. ‘Taking a
general view of the two plans, the author states that Mr. Bateman’s
has the advantage of shorter distance and smaller cost, while the
rival one has the advantage of natural storage reservoirs, and of
conferring a benefit on the inhabitants of South Lancashire. The
paper is illustrated with a map.
Besides the usual Chronicles of the progress of Geology and
Paleontology, Mining, Metallurgy, and Mineralogy, one on Arche-
ology and Ethnology has been added, which will be interesting to
many.
II.—L’Homme Fosstrz un Europe. 1867. Brussels, Muquardt ;
Paris, Reinwald. By Chevalier H. Le Hon.
EF the Gronocican Macazinz for December last, we gave a very brief
notice of this new book, which was at that time in course of
being printed. It is now published, and forms a neat octavo volume
of 360 pages, well illustrated with woodcuts and lithographic plates.
One of the illustrations is a reduced copy of the representation on
fossil ivory of the Mammoth, discovered by M. Lartet in Périgord
(see Grotocican Macazinu, Vol. III. p 480). M. le Hon considers
it to be of much higher antiquity than all human traditions. He
estimates the antiquity of man on our planet at about 30,000 years,
and states that all the evidence seems to prove that man lived in
Asia before inhabiting Europe; that towards the “ Great Glacial
Period ” the climate of the southern part of Asia was less rigid than
that of Europe, and the country more suited to the wants of the
first men, whose dentition was frugivorous rather than carnivorous (?) ;
and that during the glacial period Europe was separated from Asia,
the two continents not having been re-united until after the departure
of the waters. It was then, on the emergence of the land, that the
first immigration of man towards the west (Hurope) took place. M.
le Hon’s history ceases with the first usage of iron in the west of
Europe.
M. le Hon’s work will no doubt attain considerable popularity, as
the author has rendered it comprehensible to all, by using the simplest
language consistent with scientific accuracy; and although it is not
of so general a character as that of our distinguished countryman,
Sir Charles Lyell, being, as its title indicates, mainly confined to the
ancient remains of man in Hurope, yet it is extremely valuable and
useful as a summary of the very numerous and scattered publications
on this favourite field of enquiry in Europe. Some of the author’s
speculations show him to be a man of great ability and profound
study, but we hesitate more in this country than in France, to enter
far upon speculative grounds, preferring to ‘feel our way ’ as much
as possible before venturing beyond the region of facts.
Reviews—Australian Geology. v7
III.—Rerrort oN THE GEOLOGY AND MINERALOGY OF THE SoUTH-
Hastern District oF THE Contony or Sourn-AusTratia. By
the Rev. Jutian E. Tentson Woops, F.G.8., F.R.G.S., ete.
Adelaide. pp. 83, Map, and Section.
O the colonists of the south-eastern portion of South Australia
this pamphlet may probably be of interest, and possibly of use ;
but its utility would no doubt have been facilitated if the author had
omitted his favourite discussions on the discrimination of Upper
Miocene from Lower Pliocene. In Europe it is so difficult to pro-
nounce on this question that the Austrian geologists, accustomed to
study a remarkably complete series of such debateable deposits in con-
formable sequence, have, after years of patient endeavour, “ given it
up,” and grouped them all together. How then can a single amateur
geologist in one corner of South Australia dictate to the Geological
Survey of Victoria. and perform for deposits so far away a feat
apparently impossible to Hoernes and his colleagues in Europe ?
Mr. Woods has, in fact, obscured and rendered comparatively incom-
prehensible the really valuable material contained in his pamphlet,
by his numerous digressions on this subject, and his misconceptions
of the views of European authors, so that the ‘squatters ” of South
Australia will probably be found wanting in the patience required to
read it through.
There is, however, one subject treated of by Mr. Woods, which
requires more serious and laudatory mention, and this will be best
given by an extract from p. 26. ‘The whole of the south-eastern
district may, with the exception of a small fringe at the coast line,
be considered as a table-land gradually rising towards the boundary
of the province, near which it attains its greatest elevation. Like
all table-lands it is full of basin-like depressions upon its surface,
and is consequently drained badly. Lake-features, wherever they
occur, are more often connected with table-lands, than chains of
mountains; . . . and, . . . where the rainfall is small, and the
elevations moderate, such depressions are an inconvenience instead of
being of value. They are not deep enough to be navigable, and
during the greater part of the year are no more than unwholesome
morasses. ‘This is precisely the case in the south-eastern district of
South Australia, and what is worse, probably more than one-third of
the best land in it is utterly unavailable in consequence.” The
table-land really consists of a series of terraces, the margins of
which have a somewhat greater elevation than the land behind them,
—hence the depressions, which Mr. Woods suggests might easily be
drained by cutting channels for the water through the terrace-rims.
This is all very true, for, as the author points out, the water would
find its way into the creeks and gullies that intersect the country,
and “the expense connected with the cutting is the only difficulty in
the way of draining the district.” When labour becomes cheaper
and land more valuable, no doubt “‘ something ”’ will be done.
78 . Reports and Proceedings.
REPORTS AND PROCHHDINGS.
————>~>—_
GrorocicaL Society or Lonpon.—I. December 19, 1866.—
Warington W. Smyth, Esq., M.A., F.R.S., President, in the chair.
The following communications were read :—
1. “ On a new specimen of Telerpeton Elginense.” By Prof. T. H.
Huxley, LL.D., F.R.S.,. V.P.G:.S.
The specimen which was described in this paper had been broken
into five pieces, exhibiting hollow casts of most of the bones of
Telerpeton Elginense. It is the property of Mr. James Grant of
Lossiemouth, and came from the reptiliferous beds of that locality,
along with some highly interesting fragments of Stagonolepis and
Hyperodapedon. The casts described by the author consisted of
impressions of the bones of the skull, together with the lower jaw,
and the teeth; of most of the vertebrae and ribs; of the greater
portions of the pelvic and scapular arches; and of representatives of
most of the bones of the fore and hind limbs; and it was stated that
the characters of all these portions of the'skeleton indicated deci-
dedly Lacertilian affinities.
In describing these remains Professor Huxley discussed especially
the bi-concave character of the vertebra ; the mode of implantation
of the teeth, which he believed to be acrodont, and not thecondont ;
and the anomalous structure of the fifth digit of the hind foot, which
presents only two phalanges (a proximal and a terminal), a structure
which differs from that of all known Lacertilian reptiles, whether
recent or fossil. His researches had led him to conclude that the
animal is one of the reptilia, and is devoid of the slightest indication
of affinity with the amphibia. In all its characters it is decidedly
Saurian, and accords with the sub-order Kionocrania of the true
Lacertilia; but the author had not been able to make sure that it
possesses a columella. He also remarked that the possession by
Telerpeton Elginense of vertebrae with concave articular faces does
not interfere with this view, as although most recent Lacertilia have
concavo-convex vertebra, bi-concave vertebre much more deeply
‘excavated than those of T. Elginense are met with among the existing
eckos.
; Professor Huxley in conclusion drew attention to the interesting
fact that Telerpeton presents not a single character approximating it
towards the type of the Permian Protorosauria, or the ‘Triassic
Rhynchosaurus, and other probably Triassic African and Asiatic
allies of that genus, or to the Mesozoic Dinosauria; and that
whether the age of the deposit in which it occurs be Triassic or
Devonian, Telerpeton is a striking example of a persistent type of
animal organization.
2. “On a section at Litcham affording evidence of Land-glaciation
during the earlier part of the Glacial period in England.” By
8. V. Wood, Jun., Hsq., F.G.S.
The structure of the Lower Drift, and the limited area to which it
is confined seemed to the author to indicate that the glacial conditions
Reports and Proceedings. 79
sustained by the area under consideration were chiefly those of land-
ice, while its limited extent and rapid attenuation in all directions
from the Cromer coast have led him to infer that only a small part
of England was under water at the time. On the other hand, the
great masses of chalk and of chalky débris that were carried into the
marine sediment appear to indicate the presence, near at hand, of
some terrestrial chalk-area from which they were detached, and he
stated his belief that during this period much of the chalk of Norfolk
was covered by a great glacier. In illustration of this view Mr.
Searles Wood described a section at Litcham, in which the Chalk-
with-flintbands is seen to become gradually more impure towards the
surface, the flints becoming at the same time detached and scattered,
this disturbance having been produced, in his opinion, by a force
acting downwards from the surface, and becoming less powerful the
deeper the section descends.
3. “On the evidence of a third Boulder-clay in Norfolk.” By
F. W. Harmer, Esq. Communicated by Searles V. Wood, Jun., Esq.,
¥.G.S.
The author described a deposit of true boulder-clay, from nine to
fifteen feet in thickness, resting on the chalk, and occurring at a
slight elevation above the bottom of the valley of the Yare. It
seemed to him to be distinct in age both from the till of the Cromer
cliffs and from the much more recent boulder-clay, which caps the
high land on each side of the valley; and he gave sections which
appeared to prove that it is posterior in age, not only to the boulder-
clay, but also to the plateau-gravel capping the middle drift, by the
time necessary for the erosion of the deep valley in which it occurs.
Guoxzocica Socrury or Lonpoy.—II. January 9, 1867.—Waring-
ton W. Smyth, Hsq., M.A,, F.R.S., President, in the Chair. The
following communication was read :—
“On the age of the Lower Brick-earths of the Thames Valley.”
By W. Boyd Dawkins, M.A. (Oxon), F.G.S.
The Lower Brick-earths of the Thames Valley have been a fertile
source of discussion since the year 1836, Dr. Falconer considering
them to be anterior in age to the boulder-clay, Mr. Prestwich
believing them to belong to the Low-levei series of Quaternary
deposits. The author divides the evidence upon this question into
two heads—Physical and Paleontological. The sections at Ilford,
Grays’ Thurrock, Crayford, and Erith, evince the same sequence of
deposits. At the bottom of all are the fluviatile brick-earths and
gravels, whence the mollusca and mammalia are derived, and which
are remarkable for the horizontality of their bedding and the even
sorting of the component parts. Lying on the eroded top of these
is a deposit—the trail of Mr. Fisher—of a highly confused nature,
containing stones, often with their long axes arched, and never
sorted by the action of water. It contains also many stones and
boulders that could only have been floated to their present situation
by ice. It is as remarkable for the contortion of its bedding as the
deposits below are for their horizontality. On its uneven summit
80 Reports and Proceedings.
rests the surface-soil, which is the mere rainwash of the neighbour-
hood. These three deposits indicate three epochs: first, that of the
brick-earths, in which the water was unencountered by floating ice;
then that of the trail, which is probably a mere icewash formed
under a glacial climate; and lastly, the rainwash, formed under
temperate conditions. The date of the excavation of the Thames
Valley being uncertain, and also the fact of the boulder-clay earth
having extended into it being non-proven, it is possible that the
trail, or icewash, may be the subaérial equivalent of the boulder-
clay, and that consequently the brick-earths may be pre-glacial. The
paleontological evidence is also very important in deciding their age.
The presence of Elephas priscus and Rhinoceros megarhinus indicates
the affinity of this group of deposits to those of pre-glacial age on
the Norfolk shore, and to the foreign pliocenes. The tichorhine
and leptorhine rhinoceros, on the other hand, point towards deposits
of clearly defined post-glacial age. The beds under consideration
are also as remarkable for the absence of some as for the presence -
of others of the pleistocene mammals. The pre-glacial trogonthere,
Rhinoceros etruscus, Elephas meridionalis, Sorex moschatus, and Cervus
dicranios are absent on the one hand, the entire group of post-glacial
arctic mammalia on the other; and especially among these latter
the reindeer. From these premises, it follows that the beds in
question, as affording remains in part peculiar to the forest-bed
of Norfolk and the pliocenes of France and Italy, and in part to
the post-glacial deposits, occupy a middle point in time between
the two, being more modern than the former and more ancient
than the latter. For these reasons the author suggests the insertion
of the group of deposits in the classified list of pleistocene deposits
as follows: (1) Forest-bed of Norfolk—climate temperate; (2)
Lower Brick-earths of the Thames Valley—climate temperate; (3)
Glacial deposit—climate severe; Postglacial deposits—climate severe,
but gradually becoming temperate.
Tur Gxronocican Society or Giascow opened its session on the
20th October, and the Ep1npurGH GroLoeicaL Society on the 31st
October. Both societies commenced their sessions with an address
on “Scottish Geology, its Proofs and Problems,” by David Page,
Esq., F.R.S.E., F.G.8., President of the latter society.
In this address Mr. Page pointed out the most important facts
arrived at in Scottish geology. Passing in review the various
stratified systems, from the Laurentian up to the most modern and
superficial deposits, and after briefly indicating what had actually
been accomplished, he directed the attention of members to the yet
unsolved geological problems around them deserving their study.
There is no fear that these societies will die out for want of a
sumptuous bill of geological fare to attract them, and when the long
summer days and fine weather come round, many of Mr. Page’s
disciples will be found hammering away at these knotty problems
with a right good will.
Reports and Proceedings. 81
At the monthly meeting of the Geological Society of Glasgow
(15th November, 1866), the following papers were read :—
I. “Further observations on the Surface Geology of Glasgow.”
By Mr. James Bennie.
II." On the Silurian Scenery of the Enterkin.” By Mr. John
Dougall.
Tar Mancuuster GEOLOGICAL SocreTy continues, under the able
presidency of H. W. Binney, Hsq., F.R.S., F.G.S., to contribute a
valuable series of papers on Geology, Mining, etc., which are printed
and issued at frequent intervals. One of the most interesting papers
communicated during last session is by John Plant, Hsq., I’.G.8.,
Curator of the Salford Museum, ‘‘ On an ancient sea-beach on the
Limestone Moors near Buxton.”
About one mile south of Buxton, rises Grin Edge, a long ridge of
limestone running north-west and south-east, in the middle of a
broad valley formed by Axe Edge, Burbage Edge, Long Hill, and
Black Edge on the west and north; and by a range of lower hills on
the east and south, one of which is Harper Hill.
The highest point, called “the Tower,” on Grin Edge, is 1,435
feet above the sea level; and the top of Harper Hill has a nearly
similar elevation.
The north-western slopes of Grin Edge and Harper Hill have
been scarped into great cliffs by the extensive quarrying of the lime-
stone, carried on during many years.
The first operation in quarrying is to remove the turf and the thin
layer of loam and clay, which covers the higher ground of the hills.
In laying bare the southern slopes not far from the ridge of the
hills, the singular character of this old sea-beach is exposed.
The surface of the undisturbed rock is seen to be worn into
rounded, hollowed, and fantastic shapes, tolerably uniform in depth
and size, and extending along a regular line upon the slope of the
hills. The smooth hollows between these wave-worn stones are
filled with loose shingle, scattered about as upon any rocky coast at
the present day.
The lowest edge of this shingle beach generally ends in a line of
bold craggy rocks, at the base of which are huge blocks of rolled
stones lying upon a glacis or terrace of limestone, with a rough
uneven surface, full of deep hollows and holes, such as are found on
all rocky shores at a very low tide.
The craggy cliffs and rough rocks on the terrace are repeated at
lower levels to the bottom of the valley, not so the rocky beach and
shingle. The upper edge of this sea beach probably extends nearly
to the crown of the hills, and would therefore have an elevation
above the valley of about 400 feet.
The length of the sea beach exposed, is about half-a-mile on Grin
Edge and fully that length on Harper Hill. Standing on the old
sea beach at this latter place, and looking north-west across the
valley to the long flank of Grin Edge, the levels of the two portions
are seen to be identically the same above the bold craggy cliffs, and
VOL, IV,—NO. XXXII. 6
82 Reports and Proceedings.
there can be no doubt that the whole range of the slope of these
hills will be found marked by this beach and shingle line, whenever
the turf and clay are removed.
The turf, soil, and clay together, rarely exceed twelve inches in
thickness, covering the worn rocks and shingle of the sea beach. It
is a pure yellowish clay, free from grit and pebbles, with scarcely
any perceptible amount of lime in it. This clay fills the joints and
cracks in the limestone, and occurs in pockets of considerable extent,
as may be seen in the face of the quarries; but it yields neither
shells nor fossils of any kind, unless the bones of the larger animals
recorded as having been found in fissures filled with this clay are to
be considered contemporaneous with its deposition.
No decomposition of the limestone seems to have taken place since
the sea left the high moors of Derbyshire.
In the discussion which followed, the president, Mr. Binney, con-
curred in the view taken by Mr. Plant, that these were ancient sea
beaches, and cited the discovery of marine shells on the western
slope of Axe Edge, by Mr. Prestwich, who had obtained specimens
of Turitella, Tellina, Oardium, and LIitorina (all common on our
present coasts) from a bank of sand more than 1000 feet above the
sea.
Tae Liverpoot Gronocican Society, so ably presided over last
session by Henry Duckworth, Esq., F.L.S., F.G.S., ete., has printed
in its annual report some excellent geological materials which, with
the exception of the President’s address, are chiefly provided by
Messrs. R.. A. Eskrigge, F.G.S.; H. F. Hall, F.G.S.; G. H. Morton,
F.G.8.; Edward Nixon, Mining Engineer; and Dr. Ricketts, some
of which have already appeared in this Macazinn.
On the 16th October last, Mr. G. H. Morton, F.G.S., communicated
an excellent paper, “On the presence of Glacial Ice in the valley of
the Mersey during the Post Pliocene Period.”
After describing at length the districts around Liverpool where
Glacial striz and ice-polished rocks have been observed, and the
several directions in which they indicate the ice-streams to have
flowed over the country, the author concludes :—
From the examination of the glaciated surfaces, and of all the cir-
cumstances connected with them, I consider that the existence and
passage of a great bed of ice down the valley of the Mersey is the
only theory that will satisfactorily explain the phenomena. I can-
not enter here into all the geological observations that bear upon this
interesting subject. But one of the most important is the total
absence of that comprehensive extinct fauna which occurs in North
Wales—at Cefn Caves, within twenty-four miles from the Mersey.
About Liverpool the country seems to have been completely denuded,
partly glaciated, and finally deeply covered with Boulder-clay, con-
taining boulders almost entirely foreign to the neighbourhood, many
of them being scratched, and all having probably dropped from melt-
ing ice-bergs, during a period of subsidence which followed that of
elevation and glaciation.
Reports and Proceedings. 83
Although at a greater elevation than 120 feet, no evidences of the
existence of ice have been found, there is a possibility of their having
been removed from off the highest land, by the denuding influences
of the atmosphere, or by the sea, before being covered by the Boulder-
clay} but whether that be so or not, the moet careful search has been
made without finding the slighest evidence of ice anywhere to the
east of Liverpool, notwithstanding the great advantages presented
by the very frequent excavations made for building purposes. If the
ice were a glacier confined to the valley of the Mersey, its thickness
in the centre was about 300 feet, but there is a possibility that ice
covered the whole of this part of the country, and in that case it
must have been much thicker.
At the meeting of this Society, on November 13th, 1866, R. A.
Eskrigge, Esq., F.G.S., President, in the chair, the following papers
were read :—
“On the Oscillation of Level during the Hocene Period on the
Coast of Hampshire.” By Dr. Ricketts.
“Notes on the Geology of Leicestershire.” By G. H. Morton,
F.GS.
Tar Norwicu Grotocican Society held its anniversary meeting
on the 10th October, upon which occasion the Rev. John Gunn,
F.G.S., President, and about thirty members, sat down to dinner.
The President afterwards reviewed the various papers relating to
Hast Anglian Geology which had occupied their attention during the
past session. Among these was a paper on the Upper and Lower
Crags by Mr. J. E. Taylor (one of the most energetic and able mem-
bers of the Society) ; also an important paper by the President, on the,
“ Anglo-Belgian Basin” (read also before the British Association at
Nottingham).
The Trimmingham outlier of Chalk; the Norfolk Forest Bed ;
and many other interesting questions relating to Climatal changes,
had been considered. Great diversity of opinion exists between Mr.
B. Russell and Mesers. Gunn and Taylor as to the glacial theory.
the former gentleman strongly protesting against a glacial epoch
upon astronomical grounds, and the two latter defending it upon
geological evidences. The result of these discussions is, that mem-
bers consult ‘‘Lyell’s Principles of Geology” and other good books
of authority, and, best of all, go and make observations for them-
selves in the field.
COR aS Ow Dan Cit
LITHOLOGICAL NOMENCLATURE,
To the Editor of the GzonocioaL Macazinn.
Dzar Srr,—Neither you, nor your subscribers, will need any
recommendations of mine upon the duty of exactness in scientific
nomenclature. I am not, either, going to discuss the delicate
question of the value of applying to stones the scale of minute
84 Correspondence.
specific distinctions. This attempt, made mostly by foreign geolo-
gists, has been rather hastily extended from classificatory sciences
proper—Zoology, Botany, and Mineralogy—to rocks, although the
ulterior scientific purpose to which that method is subservient and
necessary in those sciences, namely, to ascertain how and to What
extent such minute distinctions are fixed or derivative—can scarcely
be said to exist in the philosophy of stones, our researches here
having pretty well proven that the natural selection which pre-
determines the composition of rocks is of the most fortuitous nature.
The interest in rocks turns upon other and broader points. Thus,
not seeing how the system alluded to is essential to the pursuit of
chemical geology, or of mineralogy in rocks, and fully experiencing
how great an obstruction it may prove in general geology, it is only
upon the faith that no labour is altogether in vain that I can have
any tolerance for this new fashion—it may lead to some new
development of our glorious science.
What I would wish to bring to notice is a glaring inconsistency in
the use of a familiar English rock-term. In my description of a
portion of the N.W. Himalaya, in the Memoirs of the Geological
Survey of India, wishing to avoid ambiguity, I defined the sense in
which J should use the words schist, slate, and grit. The sanction
to which I appealed was, the practise of English field-geologists.
Some friendly critic at home took me to task on this point.’ Schist,
as implying crystalline foliation (and not argillaceous rocks in
general), was allowed to pass. I will not haggle with my objector
upon a point of degree in the application of the word slate (and
slaty) to subfissile argillaceous rocks. in which that character is not
traceable to original lamination ; true cleavage is due to pressure ;
‘and so is the imperfect, though important character I would desig-
nate as slaty. Upon my use of the word grit I received no quarter.
I was perfectly aware at the time that this term was frequently used
in a totally different sense to that of my definition; but, having
served my apprenticeship in Great Britain, I was also pretty sure of
my ground when I appealed for sanction to the practice of English
field-geologists. During a recent brief visit to England, I did not
omit to verify my position. It will, I think, be granted that the
classified collections of the Geological Survey of Great Britain and
Treland are a good exponent of the authority I quoted. They are,
perhaps, the only named collections in the kingdom that are not
based upon a ‘Krantzian’ foundation. And in those collections the
word grit is frequently, I believe even exclusively, used in the sense
I gave to it. Iam writing from the Jungles, so cannot refer to the
numbers I noted in the printed catalogues of the Museums in
Jermyn-street and in Dublin, and which bear the imprimatur of
Professors Ramsay and Jukes, but the specimens are easy to be
found among the transition rocks. These grits are very fine-grained
siliceous rocks ; they appear abundantly associated with slates : their
composition and texture is such that in the midst of highly cleaved
1 See Review of “Memoirs of the Geological Survey of India,” vol. iii., Part 2,
Grotocicat Magazine, Vol. II. p. 310.
Correspondence. 85
strata they present no trace of this structure; yet no one would
think of calling them sandstones or quartzites. In their original
state I can imagine them described as very light, friable clays. The
literature of transition rocks (e.g. Professor Ramsay’s recent Memoir
on North Wales) may be consulted with the same effect as the
Survey collections. In this field of observation practice seems unani-
mous upon the necessity of a class-name for the rock in question,
and upon the appropriateness of the word grit.
On the other side of the argument are to be found all text-books,
clossaries, and lectures. It is indeed probable, that if an impromptu
show of hands could be called for, the geologists of England would
agree that a grit is a coarse, sharp sandstone—an essentially different
rock in all its characters and associations from that before described.
It is not difficult to explain such an anomaly—nine-tenths of our
geologists have done little or no work upon transition rocks ; so that
the oceasion for the ambiguous use of the term has never occurred to
them ; the remaining minority could not, all of a sudden, revoke a
familiar expression. I have yearly to fight this battle of the grits
with new assistants joining the Indian Survey, and seldom with any
good result. Naturally enough, with all the enthusiasm of youth for
the respected teachers of the schools, they prefer the recent lessons
of those high authorities to the representations of an obscuré Indian ;
and, to my great discomfiture, the oral and printed instructions of
those to whose field-practice I vainly appeal, are most frequently
quoted against me. The unfortunate result is, that this broad dis-
crepancy in our vocabulary is perpetuated in the annals of our work :
those who are set to map and describe the Coal-deposits find this
grit a very handy term, and use it triumphantly. It is with the
conviction that my respected old masters, who know both sides of
the question, will be more reasonable than their more recent pupils,
and will at least drop one or other signification, that I venture to
send home this appeal to them and to their judges, the geological
public.
To aid in the decision I call for, I will add my own notions on
the point at issue. The word grit was, I believe, introduced to us
through the Millstone-grit, from a technological vocabulary in which
we should find it applied as appropriately to a cellular trachyte. as
to a sandstone. By a true process of natural solution, it seems to
have been applied to the rock I first described—to fill a real gap in
our geological vocabulary. If this latter application of the word be
abandoned, some new word must be coined or borrowed to take its
place; whereas no such plea can be urged for the continual use of
the word as applied to sandstone—there could be no difficulty in
describing our Indian Coal-measures without a special name for one
of the many varieties of sandstone that occur. Convenience should not
be the umpire in such matters. Such a practice is unsystematic and
confusing. What would a naturalist say to the phrase—a collection
of dogs and quadrupeds? ‘Tio me, the words ‘‘a series of grits and
sandstones” sounds just as barbarous, when I know that the first
word only means a common sandstone. If, in geology, we can as”
86 Correspondence.
yet dispense with a voluminous categorical list of stones—as con-
veying no sense at all commensurate with the labour and the in-
evitable indistinctness attending such niceties of specific distinctions
—it is all the more essential that our type-names and the terminology
we apply to important characteristics should be well understood and
carefully used. We are often told to practise what we preach : in
matters of science, at least, we may adopt the easier and safer maxim
to teach what we practise.
Yours truly,
Henry B. Meputicort,
Geological Survey of India, Calcutta.
Cuora, Naaporz, December 1, 1866.
INUNDATIONS AND THEIR PREVENTION.
To the Editor of the GrotocicaL MaGazine.
Str,—Under this heading a writer in the Pall Mall Gazette, who
signs himself X, recommends the construction of “ artificial lakes” or
“huge reservoirs” on each side of the Pennine chain, ‘ which would
have the effect of preventing inundations like those of last month in
Leeds, York, Salford, etc.” X gives this idea as an origination of his
own. It is, however, Hllet’s idea, and it was published for him by
the United States Government, in a book of some 400 pages, in 1858.
The book is entitled, ‘‘The Mississippi and the Ohio rivers, containing
plans for the protection of the delta from inundation.” ‘The prin-
ciples of this book are discussed in the last chapter of “ Rain and
Rivers,” which is entitled “ Hllet on the Mississippi.” In reference
to the late floods in France, X says, ‘‘In 1856 the Emperor addressed
a letter to the Minister of the Interior on this subject, in which he
pointed out that the first object was to ascertain the cause of these
sudden floods, and suggested that they came from the rainfall among
the mountains.” And again, ‘“‘Our experience in England seems to
confirm the Emperor’s theory that certain floods are chiefly caused
by rain in mountainous districts.”” The Emperor’s theory is as cer-
tainly true, and one would have thought as self-evident as that two
and two, make four. And posterity will find it difficult to believe
that in the 19th century such a truism could have been enunciated as
a discovery! This so-thought discovery, however, is a most important
step taken in advance when we consider the profound ignorance
which prevails on the subject. And it will be of advantage to the
entire world that the most enlightened, clear-headed, and energetic
of its sovereigns has learned the first great A in the Hornbook of
Rain and Rivers. Nor is it of slight importance that the Pall Mall
megatherium has changed the tone of his roaring, and has taken to
steal, and to promulgate as his own, doctrines, which he only yester-
day attempted to controvert. He at least has the power to publish
those stolen doctrines. His own idea on alluviums was that they were
hatched out of igneous ‘“‘nest-eggs,”’ (sic) and it is really quite “a nice
change” when X finds that aqueous causes now can ‘ cover the pro-
ductive soil several feet deep by stones, etc.,” and proves that aqueous
Correspondence. 87
causes have been at this work for “ages,” by the discovery of a sub-
terranean Roman villa. But what are such floods and deposits as these
compared with those of the Nile, Ganges, Mississippi, or Niger? Itis
something, however, that X and the Emperor, ego et rex meus, are
now convinced that the late disastrous floods in France and England
were simply the effects of rain, as “the flood” was of yore. But
when my two illustrious pupils and the “ Correspondent” attempt to
remedy the effects of rain on rivers I recommend them to leave
woods out of their consideration. Our respected grandmothers always
““babbled”’ about them.—Your obedient servant,
GEORGE GREENWOOD, Colonel.
Brooxkwoop Parx, ALRESFORD,
December 18th, 1866.
THE DEVONIAN ROCKS OF DEVONSHIRE, ETC.
To the Editor of the GrotocicaL MAGAZINE.
Sir.—I do not wish to enter into a controversy on the Devonian
delusion ; J had rather let my own field work, and that of the Irish
branch of H. M’s. Geological Survey, speak for itself.
There are, however, some statements in Mr. Salter’s letter, in your
last number, which might mislead persons if they were allowed to
pass without contradiction.
There is no unconformability between any parts of the Old Red
Sandstone, either in the south-west of Ireland, or in South Wales.
The unconformability which Mr. Geikie and other of my colleagues
have shown to exist in Scotland, between beds that have hitherto
been called Old Red Sandstone, is of itself sufficient to prove that
that term can only be retained provisionally for those groups till they
are more thoroughly distinguished, and some of them freshly named.
In Ireland I adopted the local name of “Dingle beds” for the
mass of red rocks that rest in apparent conformity on the Upper
Silurian rocks, and are covered quite unconformably by the upper
part of the Old Red Sandstone,
It is by no means certain, that these ‘“‘ Dingle beds” appear
anywhere in Ireland, except in the Dingle promontory.
To the south of Dingle Bay, there is not the slightest trace of any
unconformability in the Old Red Sandstone.
Some years ago I wished to know whether the dying away of the
Old Red Sandstone in South Wales, from Herefordshire towards
Pembrokeshire, was accompanied by any break in the veins; I
examined the whole country, from the neighbourhood of Llan-
deilofawr and Llandovery, by Brecknock and Abergavenny to
Pontypool, but could not detect any direct evidence of unconform-
ability between the top of the Upper Silurian, and the base of the
Carboniferous Limestone.
In North Devon I believe it will be possible to trace a boundary
between the red rocks of Porlock, Minehead and Dunster, which are
genuine Old Red Sandstone, and the grey slates, and variously coloured
grits, and slates containing marine fossils above them.
88 Correspondence.
I do not believe that any geologist will ever be able to trace a
boundary in those slates and grits, so as to subdivide them into two
clearly marked groups, such as Ilfracombe, Combe Martin, Marwood,
Pilton beds, etc., until that is done by a good stratigraphical geo-
logist, independently of all fossil evidence. That fossil evidence is
not worth a rush in this case, because we are merely reasoning in a
circle, drawing a boundary to suit the fossil localities, and then using
the fossils to prove the correctness of the boundary. According to
the results of my field work, (hasty and imperfect enough, doubtless
in Devon, but still based upon the experience acquired by thorough
and exhaustive work, carried on patiently for years in Ireland), the
Old Red Sandstone of Porlock, Minehead and Dunster is brought up
again by a great fault in the centre of North Devon, and forms
a ridge, running from Morte Bay to Wiveliscombe, the Lynton,
Combe Martin and Ilfracombe beds being part of the Marwood and
Barnstaple beds.
If I am mistaken in this, then the central red ridge from Morte
Bay to Wiveliscombe is different from anything we have in Ireland,
and can be used to divide the grey slates of North Devon into an
Upper and Lower group, still having the genuine Old Red Sandstone
of Porlock, Minehead, and Dunster below them all, and the Coal-
measures conformably above them all.
These Devonian rocks will then rest, like their contemporaries, the
Carboniferous Slate in Ireland, between the top of the Old Red and
the base of the Coal-measures, and will be the muddy and sandy
representatives of the Carboniferous Limestone, with a somewhat
different fauna, arising partly from difference of habitat and partly
from difference of province. The contemporaneity of different
assemblages of fossils in closely adjacent areas, which is the explana-
tion of Barrande’s Colonies, has not yet been sufficiently worked out
or attended to. It has been the cause, not only of the Devonian
delusion, as I have called it above, but of the confusion among the
Cambro-Silurian series of Wales and elsewhere.
I, for one, cannot feel any confidence in the stratigraphical groups
of these rocks, established merely to suit the supposed horizons of
certain fossils, and not worked out by honest stratigraphical obser-
vations in the field. !
Lastly, let me say that I seem to myself to have been endeavouring
to fix the exact place of the so-called Devonian system instead of
explaining it away. Yours,
J. Beere Juxes.
Dusuin, January 6th, 1867.
FORM OF THE GROUND AND FAULTS IN THE DRIFT.
To the Editor of the GrotogicaL MaGazine.
Srr,—Allow me to correct a slight error which has crept into
print, although not in the proof of my paper, in your January No.
At page 9, line 5, for “became ” read become, and for “ sloping,” in
hne 10, read slope, when it will be seen that (however ill expressed)
Correspondence. 89
I refer to the old shape of the ground and not to the angles of the
overlying deposits. At foot of page 10, for ‘Benluben ” read Ben-
bulben.—While writing I may mention, in connection with the subject
of faults in drift, a suggestion, made with reference to those illus-
trated in Plate II. Fig. 8 of the above number and others, in Expla-
nation Sh. 126, Mem. Geol. Survey, Ireland, to the effect that they
might have been caused in tenaceous drift by the intersection of
planes of separation inclined towards each other so as to meet along
a line also inclined to the horizon: and enclosing wedge-shaped
masses of the material which from passage of water or from being
deprived of support at their larger ends by natural causes would
slide into lower positions; subsequent denudation settlement, etc.,
exposing faulted sections and perhaps obliterating other marks of
subsidence.
None of these drift faults or dislocations were found to penetrate
the underlying (limestone) rock, but I have heard of one from my
friend, Mr. Kinahan, which is said to fault both the Coal-measures and
superficial deposits in the Castle Corner Field.—Wishing your Maga-
zine the compliments of the season, I am truly yours,
A. B. Wynne.
Lonpon, January 1st, 1867.
DENUDATION AND THE FORM OF THE GROUND.
To the Editor of the GuotogicaL Macazine.
Srr,—My old colleague, Mr. A. B. Wynne, appears to have quite
forgotten the §.W. of Cork and Kerry, when he says in the
GrotocicaL Magazine, for January, 1867, p. 6, “Isolated rocky
pillars upon hills, the very aspects of which suggest that the stone is
being gradually disintegrated by rains.” Does he forget the
Skellings off the coast of Kerry; the Fasnet Rock (See Woodcut)
FasnetT Rock AND Licut-HovsE, coast of Cork, with soundings of 40 fathoms, 6 fathoms
from the rock
90 Correspondence.
off the coast of Cork, etc., all of which would be (according to the
charts). if the land was elevated 1000 feet, ‘isolated rocky pillars
on hills,” and yet at the present day they are being formed by Marine
action.
G. Henry Kinanan,
FAULTS IN THE DRIFT AND “TRAIL.”
To the Editor of the Grotoctcat Magazine.
Dear Srr,—Mr. 8. V. Wood, jun., in your last number, questions
the correctness of an observation made by me in the pit at the east
end of Chillesford Church. He says, ‘‘The capping of Boulder-clay,
which rests on the Chillesford beds at Chillesford, and which Mr.
Fisher, in his paper read before the Geological Society, brought into
his evidence of ‘trail,’ I believe is nothing but an oblique throw of
the Upper Drift on to the Chillesford beds;” and his reason for this
belief is, because “in a pit only a furlong and a half north of this
section, there occurs one of the junction of the Upper and Middle
Drift,” showing signs of disturbance.
Such proximity of the Boulder-clay, in situ, would seem to be a
requisite condition for the presence of trail derived from it, but I
entirely deny that its being there in a disturbed state proves my ex-
planation of its appearance at this spot to be wrong. The trail of
Boulder-clay here lies in a dish, or trough, eroded out of perfectly
horizontally bedded Chillesford clay. 'The trail is five feet thick in
the centre, and thins out to nothing at its edges. The Chillesford
beds occupy a thickness of nine feet beneath it. I saw no indications
whatever of this small bit of Boulder-clay being let in by a fault;
and I am not inexperienced in faulted clays and sands, knowing
well all the Weymouth, Bridport, and Purbeck districts.
In reference to the subject of what I have called “trail,” I take
this opportunity of mentioning a fact, which I omitted to notice
in my paper before the Society. It is, that I have in several instances
observed in the New Forest, trail containing fossil shells derived
from neighbouring fossil beds. Yet the out-crop of these fossil beds
is not discoverable by any shells in the warp. They are either
entirely dissolved or else converted into selenite. This shows
that the agency, which transported the trail, acted to a depth,
removed from the effects of ordinary atmospheric causes.
As regards faults in the Drift, there seems much difficulty in
rightly distinguishing among these beds between true faults, arising
from disturbance at a subsequent geological period, and the dis-
turbances of deposition simulating faults, such as abound in the
Norfolk cliffs. Erosion has often laid beds side by side, in a way
which looks like faulting, and though unwilling to differ from Mr.
Wood, who has so extensive an acquaintance with these deposits, I
must confess that I suspect the instance at Bulchamp to be one of
that character, because sand occurs beneath the Boulder-clay, seem-
ingly continuous with that against which it abuts. It is unusual to
meet with any true fault which does not alter the relative levels of
Correspondence. 91
stratification on either side of it. But I do not perceive that Mr. Wood
attributes this effect to the supposed faults, either at Bulchamp or at
Hitchin.—I am, yours faithfully,
QO. FisHzr.
EumstEap Rectory, CoLCHESTER.
ARE THE CORALLINE CRAG OF SUFFOLK AND THE BLACK CRAG
OF BELGIUM CONTEMPORANEOUS DEPOSITS?
To the Editor of the GuoLocicaL MaGazinu.
Dear Sir,—In 1864 I communicated a short paper to your excel-
lent Magazine on the Crags of Suffolk and Belgium. I was led from
a comparison of the lists of Mollusca, mainly, I confess, by the “ per-
centage method,” to associate the Red and Coralline Crags of Suffolk
with the Yellow Crag of Antwerp, regarding the Grey Crag and
Black Crag as anterior deposits. Mr. Godwin-Austen, in a most
instructive memoir published in the Quart. Journ. Geol. Soc. No. 87,
August, 1866, deals with the question of the Crags in a comprehensive
and philosophical manner, rejecting conclusions derived from per-
centage calculations, and regarding rather the conditions and rela-
tions indicated by the nature of the deposits and general aspect of
the fauna, which he has lately examined himself in Belgium. I
have read this memoir with great pleasure and profit, and am quite
prepared to regard the Grey Crag of Belgium as owing its apparent
distinctness from the Yellow Crag to the presence of redeposited
Black Crag fossils. But there is one point on which I would ask
for further elucidation. Mr. Godwin-Austen says (p. 238), ‘‘ The cor-
responding conditions on the English and Belgian areas of the Crag
sea are the Red Crag and the Scaldésien (Yellow and Grey Crags) ;
both are ‘remanié’ accumulations.” ‘The Red Crag was from the
break up of a neighbouring Bryozoan sea-zone, the Scaldésien from
ooze depths. Any comparison of the fossil contents of the ‘ Coral-
line Crag’ and of the ‘Crag noir’ must be subject to the considera-
tion of differences which result from depth and condition of sea-bed.”
From this I gather that the Coralline Crag in Suffolk is considered
to represent the Black Crag of Belgium, and to be contemporaneous
with it. If this is the case (apart from the objection that the fauna
of the Black Crag has an aspect so distinct from that of the three
other Crags—explained by Mr. Godwin-Austen as the result of
differences of depth), how is the occurrence of the teeth of species of
sharks and Cetacea in a “ remanié” condition in both of our Crags to
be accounted for? Specimens of the teeth of Carcharodon megalodon
and. Rhinoceros in a worn condition have been obtained from the base
of the Coralline Crag. No specimens of fish or Cetacean remains
occur in our Coralline Crag in an unworn, unrolled condition as they
do in the Black Crag. Whence, then, did the abundant “remanié”
Cetacean and shark fauna of our Red Crag come? from what de-
posits are they derived? The answer which J] have before sug-
gested to these questions, which I do not think are considered by
92 Correspondence.
Mr. Godwin-Austen, is, that the Coralline Crag was not contempo-
raneous with the Black Crag. 'The Black Crag is an older deposit
of the Crag sea, which had its representative in Suffolk, and from
which first the Coralline (in but very small numbers), and then the
Red Crag, has derived its sharks’ teeth and Cetacean bones, as have
also the Yellow and Grey Crags of Antwerp. Though the con-
ditions of the deposition of the Coralline Crag differ greatly from
those of the Red Crag, it does not follow, without further evidence,
that they were conditions contemporaneous with those under which
the Black Crag of Belgium was deposited.
I have ventured to make these few observations, in relation to the
views of so eminent a geologist, chiefly with the desire that some one
may offer a better answer to my questions.
Very truly yours,
E. Ray LanKestEr.
CuristcHuRcH, Oxrorp, January 11, 1866.
THE LOWER CARBONIFEROUS ROCKS OF NORTH WALES.
To the Editor of the GrotocicaL Macazinu.
Dear Srr,—In connection with this subject, it may interest Mr.
Green and others of your readers if I subjoin an extract from a paper
on the “ Mountain Limestone of North Wales,” read by me before
the Oswestry Field-club, on June 4, 1861, and published in the
proceedings of that Society.
“The Yoredale series, which, in Yorkshire, presents an alterna-
tion of beds of shale, limestone, sandstone, and coal, is not repre-
sented in North Wales. unless we regard the uppermost beds of lime-
stone and shale and the lowest fossiliferous layers of Millstone-grit
in our neighbourhood as occupying the same horizon, viz., lying be-
tween the limestone proper and the coarse and unfossiliferous grits.”
Such was the suggestion I offered nearly six years ago, still I
think it would be unwise to interfere with the nomenclature of the
“Survey” in this respect, especially since the change in North Wales
from calcareous to arenaceous matter is much more sudden and per-
manent than it is further north, and also while some Mountain Lime-
stone fossils extend from the base of that formation to the top of the
grit, yet at varying horizons along the belt these become associated
with plants and other fossils of the Coal-measures. J would also
observe that the top coarse beds of Mr. Green’s section are very local
in their occurrence, and give place in the neighbourhood to those of
a much finer texture.—I am, Sir, yours truly,
D. C. Daviss.
Conrycrreen House, Oswestry, January 11, 1867.
Miscellaneous. 93
MISCHUiMANHOUS.
SS
Fortation or Mrramorpuic Rocxs.—An interesting paper on the
foliation in the gneiss and schist of Yar-Connaught, by Mr. G. H.
Kinahan, has been read before the Geological Society of Ireland
during the past year, from which it appears that the foliation in the
metamorphic rocks of this district seems generally to follow some
variety of lamination, and rarely the cleavage planes. Mr. Kinahan
describes six varieties of foliation, one of which may follow the
cleavage planes, while the five others follow the lamination; the
parallel foliation being caused by parallel lamination; the oblique,
by the oblique lamination ; the spheroidal, by the spheroidal lamina-
tion; the crumpled, or wavy, by the crumpled lamination; and
the curled, by the lamination that is round the nodules. An
instructive case is cited of this structure in the townland of Killa-
guile, where the foliation of the schist curls round nodules of gneiss,
the latter being found to be obliquely foliated.
Mininc.—A series of lectures on mining by Mr. Warington Smyth,
Pres. Geol. Society, are now being published in the Mining Journal,
to which we would refer our readers interested in this subject, as
they are carefully reported, and contain all the important points
connected with that branch of our practical industry. Among the
subjects at present described are the following: the various reposi-
tories in which useful minerals were to be looked for; the distri-
bution and extension of mineral veins; the physical characters of
vein-bearing rocks; the direction of veins; the shifts or dislocation
of veins; the searching for veins, costeaning, hushing, etc. ; boring
and the different kinds of implements employed; the various modes
of breaking ground; blasting, and the kind and quality of the
explosive agent; management and superintendence of mines, etc.
A New Drnosavrran In New Jersey.—Prof. Cope described the
remains of a gigantic Dinosaur from the Cretaceous Formation
(Greensand) of New Jersey. The bones consisted of portions of
the lower jaw with teeth, and of the scapular arch, including sup-
posed clavicles, two humeri, left femur, right tibia and fibula, ete.
They were found by workmen, about two miles south of Barnes-
boro’, Gloucester Co., N. J.,in a bed which immediately underlies the
green stratum, which is of such value as a manure. In size this
creature must have equalled the Megalosaurus Bucklandi, and together
with the Dinodon, constituted the most formidable type of rapacious
terrestial vertebrates of which we have any knowledge. In its
dentition and huge prehensile claws it closely resembled Megalosaurus ;
but the femur, resembling in its proximal regions more nearly that
of the Iguanodon, indicates the probable existence of other equally
important differences,. and its pertaining to another genus. The
94 Miscellaneous.
author proposes the name of Lelaps aquilunguis for this new reptile.
Proc. Acad. Nat. Sc. Philad., 1866, p. 275.
Sxutt or Zrpeuivs.—In the “Comptes Rendus” (August 6),
Mr. Fischer records the discovery of the skull of aspecies of Ziphius,
at Lantre, on the banks of the river Gironde. The presence of
animal matter in the cerebral cavity proves the very recent death of
the creature. If the determination be true, the fact of the existence
of this cetacean at the present day is interesting, as hitherto the
references of living animals to this genus have been rather doubtful.
Species of Ziphius are well known to occur in the Crag of Antwerp,
and Prof. Huxley has lately described a specimen of Belemnoziphius
from the Red Crag of Suffolk.
The following extract from an Australian paper, will probably
not only interest, but amuse our readers :—The Coal Supply at Home.
The probable failure, at no distant date, of the supply of coal ,in
England, was evidently absorbing much general interest when the
last mail left. By a private letter, received by a gentleman in
Newcastle, which we have been permitted to peruse, we gather, that
serious apprehensions are felt by many scientific men that the supply
of coal will run out in the course of a few years. The currently
received opinion until lately was, that some fifty or sixty years
would elapse before the supply in England became exhausted, but
further investigation, it would appear, has caused several very emi-
nent men to arrive at the conclusion that a much shorter time than
that will practically exhaust the supply.—The Newcastle Chronicle.
LINES ON A SCRATCHED BOULDER.
Tell me, Geologists, I pray !
What you mean by Boulder-Clay !
Does it consist of beds contorted,
Or layers of sand and clay assorted ?
Is it unstratified or stratified ?
Can each or either view be ratified ?
Did it on floating Icebergs travel ?
Or slide down Glaciers mixed with Gravel ?
Is it this latter reconstructed
By Icebergs thawing when obstructed ?
Is it Moraine Clay or Marine ?
Or is it neither, but between ?
Was the whole country capped with ice,
Which churned the rocks up in a trice ?
Did wave, mysterious of translation,
Perform the work of denudation ?
Can you declare, with voice emphatic,
Its stones and not your views erratic?
Could but the Boulder Clay or Till
Find words ’twould call you bolder still.
Obituary. aD
(OPST EAMG peasy Nae
————E—EEE
Freperick J. Foot, M.A., F.R.G.S.1., Member Nat. Hist. Society
Dub., C.E. Geological Survey of Great Britain, has been suddenly
removed from amongst us by a melancholy accident in the early
prime of life.
On the evening of January 17th, a number of people were skating
upon the ice of Lough Kay, near Boyle, in Ireland Two of them
having ventured upon a weak portion of the ice, it gave way, and
they fell into the lake. Seeing their extreme danger, Mr. Foot came
to their assistance, andin anoble effort to save their lives lost his own.
They were both rescued, but he was drowned.
Mr. Foot was educated in Ireland, and having taken his degree
and passed through the Engineering School at Trinity College,
Dublin, where Geology forms part of the course, he became attached
to this science, and was appointed by the late Sir H. T. de la Beche on
the Ist of August, 1856, an Assistant Geologist to the Irish Branch
of the Geological Survey. Although from this date engaged in the
minute examination and active physical labour connected with his
duties on the Survey, he found time to furnish a number of botanical
and other communications to the Natural History Society of Dublin,
and several others upon Geological subjects to the British Associa-
tion, the Royal Geological Society of Ireland, the pages of the
Geologist, and other periodicals.
Amongst the latter he recorded his discovery of an interesting
group of Trappean rocks, at the Horses Glen, near Killarney, in a
paper to the Geological Society of Dublin, in June, 1856. He de-
scribed the Geology of the neighbourhood of Tralee to the Geological
Section of the British Association at Dublin in the summer of 1857.
Noticed some new localities for Posidonomya, near Ennis, in a short
paper to the Geological Society, Dublin, January, 1859; and in
another paper, ‘‘On a Recent Erratic Block,” read before the same
Society, in November, 1864; called attention to the recent transport
of a block of limestone, two tons in weight, from a distance of fifty
yards—floated by the ice of a severe winter, some years ago, from its
bed in the Shannon to shallower water near the shore.
In June, 1863, he obtained from beneath a bog in the County of
Longford the indented bones and horns of Cervus megaceros, which
furnished the subject of a paper by Professor Jukes, read before the
same Society, in December of the same year; and gave rise to much
interesting discussion and ingenious speculation as to the cause of
their being marked and indented.
During the meeting of the British Association at Cambridge, in
1862, Mr. Foot read a paper, “On the Geology of the Burren in
County Clare,” and also exhibited and described a botanical chart of
that district.
In connexion with his employment on the Survey, he contributed
96 Obituary.
wholly or in part thirteen small explanatory memoirs of the various
extensive districts which he had examined, accompanied by several
illustrations from his own pencil.
Amongst other results of his scientific observations may be men-
tioned communications to the Natural History Society of Dublin:
“On the Botany and Marine Zoology of Clare,” ‘‘On the Mammalia
of the West Coast of that county,” “On the Little Auk taken alive at
Athlone,” ‘‘On Asplenium ruta-muraria,” “On flights of Swans seen
in Roscommon and Galway, winter of 1868-4,” and ‘On the
occurrence of Hymenophyllum Tunbridgense in county Longford, and
stations of Cystopteris fragilis in the (Irish) Midland Counties.” In
March, 1859, he discovered (and recorded in the proceedings of this
Society) for the first time in Ireland, the lesser horse-shoe bat; and
in company with the late Dr. J. R. Kinahan explored various Irish
Natural History localities, the results of their labours forming
interesting papers in the Proceedings of this Society.
He paid a good deal of attention to the meteorology of the places
where he resided, and a paper by him “On a storm (called the
Prince Consort Storm) which occurred on Thursday, October 29th,
1863, at Ballinasloe,” was read before the Royal Irish Academy in
the following month.
Being so much employed in Ireland, he had not many opportunities
of extending his researches in other directions, but during short
periods of leave of absence he made visits of observation to Scotland,
Germany, Sweden, and Norway. Having returned from the latter
country but a few months since, he intended to produce papers with
illustrations containing his geological and botanical observations,
illustrated by collections and striking sketches of physical features,
etc. This design has been interrupted by his untimely death, at
the age of 36, which has deprived science of an energetic and
accurate observer; the Geological Survey of an able assistant, and
left a widow and many friends to deplore his loss.
At his residence, near Glasgow, on the 17th January, Jamzs
Smrru, of Jordan Hill, F.B.S., F.G.S., &., &c., late President of
the Geological Society of Glasgow. We shall give a notice of this
eminent and veteran geologist in our next number.
We regret to record the demise of a valuable scientific contempo-
rary, “Tue Dusiin QuarTerty JourNAL or Scizncn,” edited by
the Rev. Professor Haughton, F.G.S., etc, of Trinity College,
Dublin. We have frequently noticed this work in our Magazine,
and are extremely sorry to learn from the Kditor, that it will not be
published in future.
A New Journal of Comparative Anatomy, etc., is announced to
appear shortly, edited by Professor Newton, and Mr. J. W. Clark, of
Cambridge, and Dr. H. Percival Wright, of Dublin.
THE
GEOLOGICAL MAGAZINE.
No. XXXITI—MARCH, 1867.
@ieess GaN Aaa) TASES eae Cle sen Ss 2
SSS oe
J.—On THE RELATIVE AGES oF THE Coast BouLDER-CLAY OF
THE HASTERN COUNTIES, AND THAT ON THE HiGHER GROUND.
By Grorce Maw, F.G.S., ete.
HE discussion on Mr. Boyd Dawkins’s paper, “ On the age of
the Lower Brick-earths of the Thames valley,” at the meeting
of the Geological Society of London, 9th of January’, induces me to
submit a view of the relative ages of the Boulder-clays of the east of
England, which seems to bring into harmony the views of Mr. Daw-
kins, and the physical evidence suggested in the discussion that
seemed to conflict with them.
Mr. Dawkins’ opinion that the lower deposits of Brick-earth at
Grays’ Thurrock, Crayford, and Erith were super-imposed by a
Glacial deposit containing transported materials, was objected to
on the grounds that they occur in a valley apparently excavated
after the deposition of the Boulder-clay capping the high land to
the north of London—implying an interval between the Muswell
Hill Boulder-clay, and the supposed Glacial deposits of the Thames
Valley, represented by the entire excavation of the valley, and the
deposition of the Brick-earths and gravels, containmg mammalian
remains, underlying the Glacial beds.
The most obvious explanation seems to be the recognition of such
an interval, and the object of the following remarks is to endeavour,
by a comparison with the Glacial deposits of the Eastern Counties,
to show its probability.
The Boulder-clay of the Norfolk and Yorkshire coast (A and B,
Fig. 1), ranging from the sea level toa height of 50 to 100 feet
above high-water-mark, is generally admitted to be of a different
age to that (c) which forms the highest ground in Suffolk,
extending inland over a great part of the Eastern Counties, and
attaining a height of more than 200 feet above the sea. The two
deposits differ considerably in physical character. That on, the
lower level, commencing at high-water-mark with tough clays (B),
and transported materials, and graduating upwards at from 30 to 50
feet above the sea level, into highly contorted and quickly alternating
1 See Gronoaican Magazine, No, 32 (February) p. 79.
VOL. IV.—NO. XXXII, 7
98 Maw—Relative Ages of the Boulder-clays.
sand, silt, and clay beds (a.); the sandy or
gravelly pervading over the clayey character
in its upper part. The Boulder-clay on the
high ground (c) has a range of from 150 feet
(its base) to 220 or 280 feet above the sea,
generally resting on a bed of sand and gravel
(p) between which and the overlying clay
there is little or no gradation or interstrati-
fication. The Boulder-clay itself, compared
with that on the coast, is, throughout its
mass, remarkably uniform in this character,
and even in colour, generally free from sand
beds. It is made up of clay and chalk detri-
tus, and some transported materials, smaller
and more even in size than the foreign mat-
ter of the coast Boulder-clay (A B), and re-
markably uniform throughout the whole of
its geographical distribution. The low-level
Boulder-clay also seems to maintain its cha-
racter through a wide geographical range,
graduating upwards from very tough blue
clay at the sea-level, into contorted silty and
sandy beds, both on the east, as well as the
west coast of England and Wales. I mention
these facts rather fully to show the proba-
bility of the distinction and difference in age
of the two deposits, and that each maintains
a certain amount of uniformity of character
and position. Mr. Searles Wood, jun., has
fully recognised this, and assumes an order
of succession from the lower to the higher
clay, the latter of which he considers the
more recent. This seems to rest on evi-
oe ae
p. Sand and Gravel bed, underlying c.
d s. Lower drift; p. Middle drift; c. Upper drift.
Fig. 1.
Explanation of Section.
c. High-level Boulder-clay of Norfolk, Suffolk, and Bedfordshire.
fication of Mr. S. V. Wood, jun., a. an
5. Olli! dence not very definite, and I wish to sug-
O97 5° gest the possibility of another order of se-
more E ‘a quence, as affording an explanation of much
9° 3j0 = that is otherwise difficult to understand, and
Olga 2 as being quite as consistent with the ob-
Eos @ served facts, viz., that the Boulder-clay on
ot ote so the higher level is the more ancient, that on
otolileall | & the coast having been deposited after its
ony | i g partial denudation. With respect to the
i oe Y
difficulties that are opposed to Mr. Wood’s
views, one of the most prominent seems to
a. B. Low-level coast Boulder-clay.
ee i aia i i i ae ea
yee
ae be the analogy that may be drawn between
ailet the relative age of high and low-level river
gate gravels and the relative age of the higher
VARA and lower Boulder-clays. In the case of
Bote": river gravels, that on higher levels is ge-
nerally admitted to be the more ancient,
Maw—felative Ages of the Boulder-clays. 99
and there seems no substantial reason why the same sequence should
not hold good with respect to the Boulder-clays.
Again, another difficulty, Mr. Searles Wood at p. 4 of his remarks
in explanation of the map of the upper Tertiaries, says, ‘‘ The
Chillesford beds described by Mr. Prestwich, in 1849, as over-
lying the Red or Coralline Crags, pass up without the least break into
the Middle drift, (p Fig. 1) and are evidently part of that division.”
Although the evidence on this point is scarcely decisive, I think
the probability of the view taken by Mr. Wood is very strong.
The bed Mr. Wood describes as “‘ Middle drift,” is the gravel under-
lying the high-level Boulder-clay (p. Fig. 1), and separating it
from: the Chalk, or in some cases from the intervening Norwich
Crag. As far as my observations go the Chillesford Clay, both
in Norfolk and Suffolk, is really part and parcel of the Upper
Norwich Crag. In the well-known Crag-pit at Chillesford,
this bed, containing deep sea Arctic shells (which at Norwich is
almost immediately superimposed on the true Fluvio-marine Crag,
both occurring at the base of the beds corresponding with the Chil-
lesford Clay), lies in the midst, towards the base, of the Chilles-
ford Loam and Clay; as the Boulder-clay Till of the Norfolk and
Suffolk coast is unquestionably superimposed on the Norwich Crag,
a difficulty at once presents itself in endeavouring to interpolate
it in the Suffolk series below Mr. 8. Wood’s “ Middle-drift.” {
know it has been assumed that the Chillesford beds are the repre-
sentatives of the coast Boulder-clay, but there is nothing in its
physical character, the thickness of its mass, or condition of its
fossils, to support such an identification. At page 6 of Mr. Wood’s
paper, the difficulty in question seems to be recognized, and involves
a statement of the hypothetical possibility of the Red Crag being
newer than Mr. Wood’s Lower-drift (or Coast Boulder-clay, a. and
B. Fig. 1). ;
_ I believe there is no evidence of the direct superposition of the
high-level Boulder-clay on that of the coast. If the higher clay
was more recent than the lower, surely some cases would occur
in which direct superposition was evident. But there is no coast
section exhibiting the sequence of the high level directly over
the low-level clay, with the intervening sand bed; there are very
many instances of the coast Boulder-clay being capped with gravel,
and of the Boulder-clay of the high ground being superimposed on
a subjacent gravel bed; it must be admitted that these gravel beds
correspond in height, and in many cases present the appearance of
continuity, but proof of their identity seems to be wanting.
The Boulder-clay of the high ground of the Eastern counties, with
its subjacent gravel-bed, presents much evidence of great antiquity ;
as has been shown by Mr. Salter and Mr. Wood, it has been ex-
tensively faulted with the Chalk, and it partakes of the general
denudation contour of the country, most of the principal river-
valleys having been cut through it deeply into the Chalk and
Oolite. The small outlier at Muswell Hill (p. Fig. 2) appears to be
the remnant of a more extensive deposit, the denudation of which
100
Muswett Hirt.
THAMES VALLEY,
Maw—Relatwe Ages of the Boulder-clays.
SSS
UL
c. Lower Brick-earths of Thames Valle
o.
=
_o —=
——
A
BE
c
oO
Explanation of Section.
————
oS
Ss
Wy,
RS :
RSSSSSSS8S
Fig. 2.
B Glacial beds of Mr. Dawkins, (possibly corresponding with a and 8 of Figure 1).
y- vD. Boulder-clay
zr. Lower ‘ertiaries and Chalk.
outlier at Muswell Hill, possibly corresponding with high-level Boulder-clay (c. Fig. 1).
4. Surface soil.
accompanied the excavation of the Thames
valley. Now, if Mr. Dawkins’ view is cor-
rect, that the Brick-earths and gravels oc-
cupying this valley are overlain by a later
glacial deposit, the question at once sug-
gests itself whether this can be more pro-
perly identified with the high-level clay
of Suffolk, or the low-level Glacial depo-
sits that occur at zts own level along the
coast. If it cannot be identified with the
coast clay, you have, on Mr. Wood’s views,
the complicated difficulty .of three distinct
Boulder-clays of different ages.
1st. Mr. Wood’s “ Lower drift,” or coast
Boulder-clay.
2nd. Mr. Wood’s “Upper drift,” sepa-
rated from the first by clean gravel
beds, (‘‘ Middle drift”).
The glacial beds of Mr. Dawkins’,
overlying the beds that were depo-
sited in the Thames valley, the ex-
cavation of which appears more re-
cent than the deposition and partial
denudation of the Muswell Hill
Boulder-clay (p Fig. 2) which pro-
bably corresponds with Mr. Wood’s
“Upper drift,” or high-level clay.
I do not mean to say that such a series
of deposits during the Glacial period is
impossible, but, without any direct evi-
dence to the contrary; it seems preferable
to take the simpler view, viz., that the
beds of the Thames valley, containing
transported materials, may be an inland
extension of the Boulder-clay on the same
level, fringing the coast, and that both of
these were deposited after the deposition
and partial denudation of the Boulder-
clay on the higher ground.
Another point to be noticed is a fre-
quent terrace-like structure of the Boulder-
clay, fringing the coast, running straight
inland till it meets with rising ground of
older formation, against which it termi-
nates as though its general level was the
original surface of deposition ; this charac-
ter is not confined to any particular part
of the coast, but presents itself, on both the
east and west, wherever Boulder-clay oc-
curs on the coast. Nowif the Boulder-clay
ord.
Geol. Mag. L867. Voll. Ft. VE
E Fielding, delet lith. Vincent Brooks, Imp
Cycadean Fruits, from the Secondary Rocks. ;
Carruthers—Secondary Cycadean Fruits. 101
and drift of the higher ground is amore recent deposit it must originally
have extended coastwise, and spread over the present low-level clay.
It is strange, in this case, that no remnant of such super-position
exists, and that the denudation, which must have removed the
upper deposit, should have left the lower with such a regular plat-
form-like structure throughout so great a range of coast cirewt. I
am not prepared to say that this could not have been the result of
marine erosion, working at a higher level than the present coast-line ;
but taking other evidence into consideration it would appear that in
this approximately level surface, we have the original surface of
deposition, which took place in comparatively shallow water.
Wherever the older rocks rise up to more than 100 or 150 feet above
the sea level, the coast Boulder-clay ‘throws out,” and instead of
following the irregular basement line, and rising of its full thickness
with the subjacent formation, it rapidly thins out to nothing, and is
lost at a height of 100 and 150 feet above the sea level.
In the case of the inland deposit of Drift and Boulder-clay on the
higher ground of the centre, and west of the country, it is difficult
to directly identify it with that on the higher ground of Suffolk,
Norfolk, and Bedfordshire. The various levels at which it occurs is
remarkable, and can only be accounted for, either on the theory of
unequal elevation, or from the whole having been progressively
deposited during a submergence, in extent, equal to the altitude of
the highest drift; but, as before observed, the general level of the
terrace of clay, fringing the coast of Norfolk and Yorkshire on the
east, and of Wales and Lancashire on the west, seems to point to an
uniformity of age, and to distinguish it from the Boulder-clay and
drift occurring at various higher levels, and it is with it, rather than
that on the higher ground, that the supposed Glacial beds overlying
the Brick-earths and gravels of the Thames valley may possibly be
identified.
JI.—On Somu Cycapean Frurrs rrom tHe SuconpaRy Rocks 6F
Britain."
By WixiraM Carrutuers, F.L.S. of the Botanical Department, British Museum.
(PLATE VI.)
WO of the Gymnospermatous Orders are represented by fruits
found in Secondary strata, viz., Cycadece and Conifere ; ® no re-
mains have been observed, as far as I know of any plant belonging
to the Gnetacez.? 'There is satisfactory evidence of the existence of
Conifere from the period of the Old Red Sandstone; but it is very
doubtful whether the Paleozoic fruits and leaves which have been
referred to Cycadee have anything whatever to do with that order.
1 Reprinted (with some additional notes and alterations) from the “Journal of
Botany” for January, 1867.
2 For an account of the Coniferous Fruits, see Mr. Carruthers’ papers in the
GroLocicaL Magzine, Vol. III., p. 534, Plate XX. and XXI.; and ‘“ On Aran-
carian Cones,’ Vol. I11., p. 249, Plate XI.
3 Goeppert found a small fragment of what he believes to be an Ephedra in amber,
which he has called Ephedrites Johnianus.
102 Carruthers—Secondary Cycadean Fruits.
Fossil wood, leaves, and fruits, afford the means of determining
the existence of vegetables during any geological period.
The trunks and foliage of Cycadee are so remarkable that fossil
fragments of them can, as a rule, be determined with certainty. ‘The
trunks are generally short, and composed externally of the basis of
the leaves, while internally they consist of a large medulla, either
simple or traversed by numerous vascular bundles, and surrounded
by one or more woody cylinders. The trunks from Purbeck, which
Buckland named Cycadeoidea, specimens of which have also been
found in the Oolite of Helmodale, Sutherlandshire, by Mr. Ch. W.
Peach, and those from the Wealden, named Clathraria by Man-
tell, have all the characters of Cycadean stems. The leaves are
remarkably uniform in the modern representatives of the order.
With a single exception they are pinnated, hard, and woody, and
the leaflets have fine, simple parallel veins. The genus Stangeria
has paralled forked veins like those of a Lomaria, and we fear
that this anomalous structure has induced paleontologists to place
among the Cycadee some fossils which would more correctly be
referred to Ferns. The cones of Cycadee are less frequent fossils
than either the leaves or the stems. In a former paper (Vol. IIL.
p- 585), I exhibited the characters by which Cycadean cones are
distinguished from those belonging to the Conifere. I may here
further add that the scales of the Cycadean cone have a much simpler
arrangement than in that of Conifere. In Cycadee the scales are
arranged either in a vertical series, as in the female cone of Zamia,
or the secondary spirals consist of only two series, and the amount
of obliquity in their direction is the same whether they wind to the
left or to the right, as in Encephalartos.
Corda, in Reuss’s “‘ Die Versteinerungen der Bohmischen Kriede-
formation,” says he has never seen any real fossil Cycadean fruits,
except the two that he there describes. These are Microzamia gibba,
a female cone, unlike any recent Cycadean cone in having from
three to six seeds supported by each scale, and Zamiostrobus famili-
aris, which from the form of the scales, and from haying vascular
bundles scattered through the medulla of the axis, he considers a
true Cycad, and probably the male cone of the former species.
Endlicher established the genus Zamiostrobus for a cone he believed _
to be Cycadean. But as I have formerly shown (I. c., p. 536),
it was founded in error, and great confusion has since been created
by making it the receptacle for cones, whose affinities could not be
made out. Of the seven species now placed in the genus, I have shown
four to be Conifere. What Z. Fitton, Ung., may be or may not
be, it is impossible to say from Fitton’s drawing in the “ Geological
Transactions,” 2nd series, vol. iv. t. xxii. f. 11. Fitton had a longi-
tudinal section of it made, but he tells us (1. c. p. 849) that it “did
not exhibit any indication of vegetable structure.” In the British
Museum there is a cast of a cone belonging to C. B. Rose, Hsq.,
which corresponds remarkably with Fitton’s figure. It was obtained
from the Lower Greensand at Downham, near Lynn, Norfolk ; but
I believe the original specimen has decomposed, like so many pyritic
Carruthers—Secondary Cycadean Fruits. 103
fossils, so that it can throw no light on the matter. Corda, after a
fresh examination of Z. familiaris, Ung., has shown it to be Cyca-
dean; and the remaining species, Z crassus, is most probably Cyca-
dean, although the materials for its determination are not entirely
satisfactory.
A singular fossil occurs at Runswick Bay in the Lower Oolite, to
_ which Lindley and Hutton give the name of Zamia gigas. James
Yates, Hsq., and Prof. Williamson, have examined the structure of
this plant. Prof. Williamson originally considered the “collar”
(the so-called fruit of the fossil) as a series of protecting scales,
beyond which the axis was prolonged to support a cone.’ Mr.
Yates, whose extensive acquaintance with Cycadee is well known,
and who has greatly helped me in my investigations, not only with
his advice but also by presenting his large collection of dried speci-
mens of Cycadean stems, foliage, and fruit, to the British Museum,
saw no indication of this cone in the numerous specimens he ex-
amined. He says, regarding this fossil,’ that its pinnate leaves “ have
unquestionably a very close resemblance to the leaves of Zamia.
But here the analogy seems to cease. The stem does not resemble
the stem or the mode of growth of any recent species of Zamia, and
a still greater difficulty presents itself in its fruit.” Mr. Yates con-
siders that the “collar” contains the fruit, and Prof. Williamson
seems to have ultimately arrived at the same conclusion, for he says’
the fossil contains two distinct forms of fruits.. “The one, a curious
scaly axis, prolonged in a peculiar pyriform manner, which latter
part has been invested by a cortical substance, consisting of oblong
cells arranged perpendicularly to the axis. This was probably the
antheriferous portion. The second form consists of a concave disk.
which has evidently terminated the woody axis, and been margined
by a peripheral circle of radiating bracts. On the upper portion of
each of these bracts are two small oblong depressions which may
have supported two ovules.” J have examined numerous specimens of
this fossil in the British Museum, but have been unable to determine
satisfactorily anything in regard to the precise structure of this ano-
malous fruit. It presents so many peculiarities unknown in the
fruit of any modern Cycad, that for the present at least, and not-
eee its Zamia-like leaves, I must consider it a doubtful
yead.
The cones I am about to describe have several features in com-
mon, which show that they belong to this Order. They have all the
simple arrangement, or phyllotaxis of the scales of the cones. The
peduncle, when indications of it are present, as in C. elegans and C.
truncatus, is larger than in Coniferous cones of the same size. The
cones are converted into iron pyrites, a mineral condition unfavour-
able to the preservation of structure, but the arrangement of the
mineral shows that the general direction of the parts of which the
cone was composed was at right angles to the axis (Plate VI.,
Fig. 2.) A specimen from the collection of the late Robert Brown,
1 Proceedings of York Phil. Soc , 1847, p. 46. 2 Tb. p. 39.
3 Transactions of the British Association, 1854, p. 103.
104 Carruthers—Secondary Cycadean Fruits.
which he had sliced, fortunately exhibits, to some extent, the in-
ternal structure. This fragmentary specimen is a portion of the
base of a cone (Hig. 4), and the magnified section (Fig. 5) is per-
pendicular to the axis. The axis itself is wanting. The scales leave
the axis at a right angle, except those at the very base, which
slightly incline downwards. They have a thickened peltate apex,
not imbricated, composed of loose cellular tissue. The longitudinal
section necessarily shows a single seed connected with each scale.
The seed had a thick testa, indicated by the thick dark line in the
sketch. The contents of the seed have disappeared, leaving only
the shrivelled-up tegmen still attached at the base of the seed, though
apparently free at the apex. A rolled cone, four scales of which are
represented at Fig. 7, has the apices of the scales nearly rubbed off,
and exhibits the bases of the seed at their attachment to the scale ;
and this shows that there are only two seeds to each scale.
The recent genus to which these fruits are most nearly related is
the South African genus Encephalartos. Associated with the cones
at Brook Point are found trunks of Clathraria, of which, no doubt,
they were the fruits. The form and structure of these trunks con-
firm the affinity of the Wealden Cycads to Encephalartos. In both,
the trunks are tall and cylindrical, and the medulla is traversed
by numerous vascular bundles.
As long as we are unable to refer these fruits to the species to
which they belong, it is desirable that they should have provisional
names by which they may be known. To prevent confusion, I will
avoid Endlicher’s generic name Zamiostrobus, and propose Cycadeo-
strobus as a suitable designation, giving no further definition to the
genus, tham that it contains fossils that are supposed to be the fruits
of Cycadee.
1. Cycadeostrobus ovatus. Cone ovate; scales somewhat broader
than deep. (Pl. VI. Figs. 1 and 2.)
The specimen of this cone, which is two inches long by a little
more than one and a-half broad, is less compressed than the other
specimens figured. It has been cut longitudinally through the
axis, but does not exhibit any structure.
From the Wealden at Brook Point, Isle of Wight.
2. C. truncatus. Cone ovate, truncate, and widest at the base,
narrowing upwards from the middle to its obtuse apex; scales about
a third broader than deep. (PI. VI. Fig. 3.)
There are three specimens of this cone in the British Museum,
from the collection of Dr. Mantell. One specimen has the scar of
a large peduncle. In another the scales are preserved in relief, and
show that they had a tumid pyramidal apex.
3. C. tumidus. Cone, oblong-acuminate ; scales about as broad
as long, the apex rising into a tumid pyramid. (Plate VI. Fig. 6).
A single specimen of this distinct little cone, an inch and a
quarter long by three-quarters broad, is in the British Museum. It
is from Brook Point.
4, C. elegans. Cone ovoid, truncate below ; scales nearly as deep
as they are wide. (Plate VI. Fig. 9.)
Carruthers—Secondary Cycadean Fruits. 105
There are two specimens of this cone in the British Museum,
from the collection of Lady Hastings. They are two and a-half
inches long, by one and a-half broad. The base is not only
truncate, but somewhat indented, and there is the remains of a
large peduncle, having a diameter of nearly half-an-inch. There 1s
a third specimen in the Geological Museum at Jermyn Street.
From the Wealden, Brook Point. ¥
5. C. Walkeri. Cone oblong ; scales broader than deep.
This cone is figured by Mr. J. F. Walker, in the Annals and Mag.
of Nat. Hist. ser. 8, vol. 18 (plate xiii. fig. 5), and described as a
Cycadean cone (p. 384), two and a-half inches long and two and
three-quarters in circumference. The specimen is evidently very
much waterworn. Perhaps the specimen in the British Museum
from which the four scales (Plate VI. Fig. 7) were drawn, belongs
to this species.
From a phosphatic deposit in the Lower Greensand, at Sandy,
Bedfordshire, probably of Wealden age.
6. CO. sphericus. Cone spherical; scales as deep as they are
broad. (Plate VI. Fig. 8).
This cone is very much compressed and imperfectly preserved,
but is evidently different from the others.
From the Oxford clay of Wiltshire.
7. C. primevus. Cone ovate; scales as broad as they are deep.—
Pinus primeva, Lindl. and Hutt. Foss. Fl. Tabl. 135. Pinites pri-
mevus, Morris, Cat. p. 18.
The scales of this cone are six deep and six round. Tach one is
dilated at its extremity, and gradually thins away towards the axis.
From the Inferior Oolite at Burcott Wood and Livingstone.
8. C. Brunonis. Scales twice as broad as they are deep. (Plate
VI. Fig. 4 and 5.)
The single specimen of this species is a fragment from the base of
alarge cone. It is from the collection of the late Robert Brown.
The fragment is two inches in diameter. The very broad scales
easily separate it from the other species.
Locality unknown.
9. (?) Zamia crassa, Lindl. and Hutt. Foss. Flor. t. 136. This is
probably a Cycadean cone. The authors of the “ Fossil Flora” de-
cribe it as having “in transverse section numerous seeds lying
below the thickened ends of the scales at a considerable distance
from the thick axis.” It is too imperfect to decide positively as
to its affinities.
From the Wealden, at Yarenland, Isle of Wight.
There is a cast in white sandstone of a vegetable organism,
probably Cycadean, but whether part of a trunk or of a fruit I am
unable to determine, from Brora, presented to the Geological Museum,
Jermyn Street, by Sir Rod. I. Murchison, Bart. I notice this here
that I may suggest, to those who have an opportunity of visiting
the Secondary deposits of the North of Scotland, how desirable it
is to have additional specimens, so as to determine more accurately
the remarkably interesting Flora of these beds.
106 Rofe—On the late Collery Explosions.
EXPLANATION OF PLATE YI.
Fig. 1.—Cycadeostrobus ovatus.
», 2.—Longitudinal section of same.
9) o.—C. truncatus.
» 4.—C. Brunonis.
,», 6.—Portion of a longitudinal section of same (twice the natural size).
5, §.—C. tumidus.
», 7?.—Four scales of a water-worn cone, showing the bases of the two seeds under
each scale.
» &—C. sphericus.
» 9.—C. elegans.
*,* I am indebted to my colleague, Mr. W. Carruthers, F.L.S., for the use of
this Plate, which has already appeared in the ‘‘ Journal of Botany,” for January,
1867, together with the descriptions of the species which accompany it, to which
latter the author has made several additional notes.—H. W.
III. Norse on tur tate Contiery Expxosions.!
By Joun Rors, C.E., F.G.S.
aa recent deplorable explosions in the Barnsley and North
Staffordshire Coal Fields have again called attention to the
coincidence of such terrible accidents with a sudden fall of the
barometer, by which they are so frequently preceded, suggesting the
idea that they may be to some extent connected as cause and effect,
and perhaps the following facts may induce a belief that there is
truth in the supposition.
Some years since (in 1848) my attention was called to a well at
Whittingham, on a farm then and now occupied by Mr. John
France, about four miles N.W. of Preston, in Lancashire, celebrated
in the district as ‘‘ the blowing well.” This well was sunk for the
purpose of supplying the farm buildings with water, but after going
down about eighty feet in vain, the work was abandoned, and the
well was covered with a large flagstone, with a hole through it
for the chain used in placing it on the well. It was then noticed
that the well answered the purpose of a weather glass, for whenever
the barometer fell wind blew out of the well, and when it rose the
draught was inwards, and with more or less force according to thé
rapidity of the change. The tenant occasionally put a tin horn into
the hole in the flag and then the sound could be heard at a consider-
able distance. .
Some time after this I had occasion to sink a well for a cesspool
to get rid of the offensive residue from some chemical works. This
was sunk about twenty-eight feet deep in dry loose sand, and it
was arched over, leaving no opening but a pipe through which the
liquid refuse was passed when required. This well acted in the
same way as the above, as was soon made unpleasantly evident, for
when the atmospheric pressure was decreasing, the air came from the
1 This communication was sent to the Editor on the 10th of January. From the
evidence since given at the Inquest on the Barnsley accident, it appears that the coal-
owners provided a barometer and ordered extra firing in the upcast shaft when the
glass fell rapidly, so that it seems the effect of rapid atmospheric changes was known,
and, to some extent at least, provided for; but we still think Mr. Rofe’s note deserving
publication, as collateral evidence of the atmospheric action alluded to.— Edit.
Rofe—On the late Colhery Explosions. 107
well, loaded to a disagreeable extent with the offensive vapour from
the cesspool. On continuing my observations with a barometer I
found similar results to those at the “blowing well” at Whittingham.
These results, however, are exactly what, on consideration, would
be expected. The air in the well, on any diminution of the atmos-
pheric pressure, would necessarily expand and pass from the well,
and on any increase of pressure the reverse must take place.
Now if we apply this reasoning to a coal mine, which, for the pur-
pose of this argument, may be considered as merely an immense
subterranean excavation, connected with the external atmosphere
only by the up and down cast shafts, we should expect the air in the
mine to expand when the atmospheric pressure is diminished; and
if that expansion were sudden and great it would probably supply
as much air as the upcast was passing, without drawing an equi-
valent quantity of fresh air through the downcast; and at the same
time, by the diminution of the pressure, the gas generated or con-
fined in the pores and fissures of the coal would be expanded or set
free more rapidly, and thus cause an excess of gas in the air of the
mine, which, if it meets with an open lamp, a smoker’s pipe, or any
other means of ignition, spreads death and destruction around.
It may, perhaps, be remarked, that if sudden variations of atmos-
pheric pressure acted in this way there would be more explosions
than there are; but, fortunately, these dreadful accidents require a
concurrence of circumstances to cause them. There must be an excess
of gas in the mine, and, at the same time, whether from accident or
carelessness, a means of ignition. The chances are that these would
be only occasionally concurrent, and then, only, explosions would
take place.
The lesson to be drawn from these remarks is that coal proprie-
tors should take especial notice of any considerable fall in the baro-
meter, and at such times force an extra ventilation either by additional
firmg at the upcast, by a steam jet, or by any other means which
their experience may suggest; but by some means or other they
should increase the ventilation when any sudden diminution of
atmospheric pressure takes place.
If there should be nothing new in the above remarks, I make no
excuse for offering them, because the consequences of these explo-
sions are so awful that it becomes the duty of every one to suggest
any precautionary measures he may have reason to believe could, in
any degree, tend to prevent them, even at the risk of exposing his
ignorance of what may have been already carried into practice.
IV.—Own some Fossins rrom THE Lower Sinurtan Rocks oF THE
Sout oF ScorLanp.
By Henry AtiEynE Nicuozson, B.Sc.
(PLATE VII.)
HE Lower Silurian Rocks of the South of Scotland, below the
level of the Wrae Limestone of Peeblesshire, though of great
thickness, and little altered by igneous agency, have as yet yielded
108 Nicholson—On Graptolies.
but few of the higher forms of animal life. Two species of a
phyllopod crustacean,! (Peltocaris aptychoides and P. Harknessi,
Salter), were discovered by Prof. Harkness, along with the first
Brachiopod found in these deposits, the Siphonotreta micula of McCoy.
Another crustacean of an allied genus, described by Mr. Henry
Woodward,? and named by him Discinocaris Browniana, was dis-
covered last year in the neighbourhood of Moffat, by Mr. D. J. Brown.
Besides the above, there occur traces of the action of marine worms,
and I have, in addition, found one, possibly two, species of Lingula,
a thin-walled Orthoceras, or Pteropod, and some curious spine-like
bodies, probably referable to crustaceans. With the exception of
these scanty remains, the strata under consideration have yielded no
fossils higher in the scale of existence than Graptolites. In no
other British deposit do we, however, find a greater profusion of
these beautiful and characteristic fossils, or a greater number of
specific types. It is the object of this communication to describe
certain new forms of Graptolites which have come under my
notice, together with one remarkable genus, apparently allied to the
Graptolitide, though probably representing a different order.
Corynoides calicularis, gen. nov. (Plate VII. Figs. 9-11). In the
more anthracitic shales of Dobbs’ Linn, and of Hart Fell, near
Moffat, there occur certain singular fossils, for which I have adopted,
at Prof. Harkness’ suggestion, the generic name Corynoides, and have
appended the specific title calicularis. ‘These occur in the same state
of fossilization, as do the Graptolites,.viz., as flattened pyritous
impressions, and though often occurring in considerable number, they
present a great similarity to one another in size, and in their general
characters. The stipe varies in length from one-third to half an
inch, and has an average breadth of one-twentieth of an inch; the
base, or proximal extremity, is provided with two small, slightly
diverging spines or mucros (Fig. 9), which are wanting in other
less perfect specimens, when the stipe terminates below by tapering
to a point (Fig. 10). There are no cellules, the lateral margins of
the stipe being perfectly plain; but the polypary expands at its
distal extremity into a sort of cup or calyx, the free edge of which
is divided into four or five equal or unequal teeth. ‘There are no
certain traces of any central solid axis, but the surface of the stipe
is sometimes striated. From the above description it will be evident
that Corynoides forms a simple hollow tube, probably corneous,
provided with a single or double radicle or mucro, and developed
distally into a cup-like “ hydrotheca.” Unlike the Graptohtide, proper
Corynoides, has evidently been composed of a single polypite only,
though it resembles the typical Graptolites, in having been apparently
free and oceanic, and in the possession of a corneous or sub-calcareous
test or polypary. Corynoides seems to be most closely analogous to
some of the Corynide or Tubularide of our own seas, especially
resembling such forms as Coryomorpha, in which there is but a single
polypite. It cannot, however, be considered to be absolutely refer-
able to the Corynide, since no known Corynid exists as a free-floating
1 See Quart. Journ. Geol. Soc. Vol. xix., p. 87. 2 Op. cit., Vol. xxii., p. 503,
Nicholson— On Graptolites. 109
and independent organism, such as Corynoides seems undoubtedly to
have been.
Diplograpsus tubulariformis, n. sp. (Plate VII. Figs. 12-15). This
hitherto undescribed species seems to constitute a transition-form
between Corynoides and the true Graptolites, being, however, itself
referable to the latter, and belonging to the genus Diplograpsus.
The stipe is flattened, simple, from one-third to half an inch in
length, celluliferous on the two sides for a short distance above, and
tapering gradually towards the base, so as to form a long, pointed,
non-celluliferous portion or radicle, which occupies half or more of
the entire length of the stipe. ‘The axis is capillary, usually pro-
longed beyond the celluliferous portion of the stipe, and apparently
double in its composition, as shown by its occasionally splitting at
the summit. Celluliferous portion of the stipe from one-tenth to
one-eighth of an inch in breadth, bearing from three to six cellules
on each side, and terminating above abruptly by a straight or curved
margin, which is usually fringed with terminal cellules. Cellules
pointed, about eighteen in the space of an inch, forming a very acute
angle with the axis (about 15 degrees); their upper portions more
or less free; the upper margin of the denticle directed at right
angles with the axis, or more or less downwards. In some of my
specimens the broad and tapering radicle, which characterises the
species, is present, but the lateral cellules are reduced in number
(Figs. 13-14), or seem even to be altogether absent (Figs. 15), when
the stipe terminates in a curved or straight celluliferous margin.
The pointed denticles, which are seen in these cases, may possibly
not be true cellules, but may be due to breakage of the stipe, and
under any circumstances this form would appear to be only a variety.
In the extreme cases, as in Fig. 15, there seems to be a close
approximation to Corynoides. Loe.—Shales of Duffkinnel Burn,
near Wamphray.
Diplograpsus accuminatus, n. sp. (Pl. VII. Figs. 16-17.) I have
proposed this name for a species of Diplograpsus, which occurs
pretty generally in the Dumfriesshire shales, and is certainly dis-
-tinct from any described British species.
Spec. Char.—Stipe celluliferous on both sides; usually not more
than half an inch in length, seldom reaching one inch; average
breadth one-twentieth of an inch; tapering gradually towards the
base, where it ends in a long and pointed radicle. Axis slender,
capillary, often prolonged beyond the celluliferous portion of the
stipe, for a quarter to halfan inch. Cellules about twenty in the space
of an inch, alternating distinctly with one another on the two sides
of the stipe, and projecting as prominent teeth, the free extremities
of which are generally acute and sub-mucronate, sometimes rounded
off and obtuse. The cellules are usually one-third as broad as they
are long; their outer margin is straight, or slightly curved, and their
upper margin at right angles with the axis—sometimes directed
upwards, rarely downwards. This species, when well-marked, as in
Fig. 16, is easily recognized by its pointed radicle, which gradually
becomes continuous with the body of the stipe, its small width, the
110 Nicholson—On Graptolites.
few cellules in an inch, and the marked alternation of the toothed and
angular denticles. These characters seem to me to entitle it to rank
as a distinct species ; but the genus Diplograpsus is in such an
unsatisfactory condition, that it may eventually turn out to be a
variety of some previously-described species. I have included some
forms, in which the denticles are rounded, instead of angular, as the
cellules distinctly alternate, and the stipe commences in a pointed
radicle (see Fig. 17) ; but I doubt whether these are differences of
variety or specific distinctions. D. acuminatus somewhat resembles
Graptolithus, (Diplograpsus) angustifolius, of Hall, but is certainly
distinct. It is also not unlike a species which occurs in the Skiddaw
Slates, and has been doubtfully referred by Mr. Salter to D. pristis.
Loc.—Dobbs’ Linn, Duffkinnel Burn; Garple Linn, in Dumfries-
shire.
Didymograpsus anceps, n. sp. (Plate VII. Figs. 18-20.) This
peculiar form of Didymograpsus differs from all others with which I
am acquainted, in the total absence, or very rudimentary condition,
of the radicle or initial point. So much is this the case, that it
might at first sight be considered to be merely a mono-prionidian
Graptolite, accidentally bent ; but this supposition is negatived by
the fact that there occur numerous specimens, the branches of which
are bent at the same angle andin the same way, while the serratures
point in the same direction in both branches.
The frond consists of two stipes, coming off from a point, which
is not, as a rule, marked by any radicle (Figs 19-20), though a
minute mucro is to be discovered in some specimens apparently
belonging to this species (Fig. 18). In these cases the mucro is
internal, and the cellules are on the outer or convex side of the
frond. Considering this as the normal position, the stipes bend
downwards from their origin, including between them an angle of
20° or thereabouts, and extending in a straight or slightly curved
direction for a greater or less distance. The stipes rapidly attain
their maximum breadth (nearly one line), retaining the same dimen-
tions, and showing no signs of terminating as far as seen—a length
of two inches being reached in the larger specimens. Cellules,
twenty-five to thirty in the space of an inch, their extremities
rounded off, and their margins strongly curved, so that the denticles
are separated by indentations, which are rounded at the bottom, and
extend about half-way across the stipe (Fgs. 18a. 20a.) Sometimes
there are minute pustules, or circular depressions in the centre of
each denticle, where it joins the body of the stipe, but this does not
seem to be at all constant.
This species is very easily distinguished, both by the absence of
any prominent and conspicuous radicle, and by the peculiar form of
the cellules, in which latter respect it differs from all British species,
and closely resembles Graptolithus (Didymograpsus) divaricatus,
Hall, which is found in the Hudson River Group. Loc.—Dobbs’s
Linn, near Moffat.
Didymograpsus flaccidus, Hall, Sp. (Plate VII. Figs. 1—3.)
This exceedingly distinct and beautiful species appears to be iden-
Nicholson— On Graptolites. 111
tical with the Graptolithus flaccidus of Hall, which occurs in the
Utica Slate, the American equivalent of our Upper Llandeilo Rocks.
I am not aware that it has been before recognized as occurring in
Great Britain, but I have found it in tolerable plenty in the anthra-
citic shales of Dobbs’ Linn and Hart Fell, near Moffat. For its
specific characters I may refer to Hall’s description, (Graptolites of
the Quebec Group, Supp. p. 143, Plate II., Figs. 17-19.)
D. flaccidus is at once distinguished from all other species of
Didymograpsus, by the slender and flexuous stipes (Fig. 1), each of
which may attain a length of nearly half a foot, without showing
any sign of a termination. The cellules are on the convex side of
the frond, the denticles angular or rounded. The mucro is on the
concave side of the frond, sometimes short and obtuse, as in Hall’s
specimens ; sometimes, however, attaining a length of one-tenth of
an inch. In most of the specimens in my possession, the margin
opposite to the mucro is ornamented with three small spines (Figs.
2 and 3), one directly opposite to the radicle, and one springing
from the apex of the first cellule on each side. Ona cursory examin-
ation the entire frond may be confounded with Graptolithus tenuis,
unless the presence of a radicle should be detected.
Diplograpsus quadri-mucronatus. Hall, sp. (Plate VII. Figs. 6-8.)
This is another Utica Slate species, which I have found in the shales
of Dobbs’ Linn, though it is not of common occurrence. It has a
considerable resemblance to D. Whitfieldi, Hall (Fig. 4), but is
altogether a larger form, and is distinguished by the fact that each
cellule is provided with two mucronate points, one arising from each
angle, whereas, in the latter species, there is only one such mucro to
each denticle. For the specific characters of D. quadri-mucronatus,
Hall’s description should be consulted. (‘‘ Graptolites of the Quebec
Group,” Supp. p. 144, plate xiii. figs. 1-10.)
Diplograpsus Whitfieldi, Hall, sp. (Plate VII. Figs. 4 and 4a.)
I believe this species has usually been confounded with D. mucro-
natus, Hall, (Fig. 5), especially as they often occur together. ‘The
two are, however, distinguished from one another by good charac-
ters. In D. Whitfieldi the denticles are “shallow and angular,”
whilst the mucros are rigid, and maintain a persistent horizontal or
shghtly upward direction. In D. Mucronatus, on the other hand,
the denticles are prolonged into slender and prominent teeth,
furnished at their extremities with flexible spines, which have no
constant position, but are twisted in every direction, (see Fig. 5a.)
For the description of D. Whitfieldi, see Hall’s Paleontology of New
York, Vol. iii. supp. p. 516. Loc.—Common in the anthracitic
shales of Glenkiln Burn, Dumfriesshire.
Germs of Graptolites (Plate VII. Figs. 21-24. The occurrence
of minute bodies, possessing a graptolitic texture, provided with
a corneous envelope, and differing in form from all known spe-
cies of graptclites, was first investigated by Professor James Hall,
to whom we owe so much of our knowledge of the Graptolitide.
(See Paleontology of New York, vol. iii., supplement and ‘“ Grap-
tolites of the Quebec group,” pp. 83-35; plate B., figs. 12-19).
112 Nicholson— On Graptolites.
These curious fossils were considered by him to be the germs
or embryonic forms of Graptolites, and there can hardly be any
doubt as to the correctness of this conjecture. Numerous bodies,
very similar to those described by Hall, occur in the graptolitic
shales of Dumfriesshire,’ and have, in all probability, a similar
origin. It should be observed that the form and texture of these
germs constitute a strong argument against the conclusion that the
Graptolitide are Polyzoa, and support those who wish to place the
Graptolites among the Hydrozoa, a view which is further sustained
by the occurrence of forms like Corynoides, and by the discovery of
bodies resembling ‘‘ ovarian vesicles,” as noticed by Hall and by
myself, (see op. cit. supra, also the Gronrocican Macazrne, October,
1866
It is, of course, in most cases impossible to refer the embryonic
Graptolite to any known adult form; still, this can sometimes be
done with tolerable certainty. Thus, in the anthracitic shales of
Hart Fell, where Diplograpsus pristis is the predominant species,
there occur innumerable germs, which in their more advanced stages
appear referable to the above-mentioned species. Among these,
three main varieties present themselves, which, are probably, merely
as many different stages of development. The first and youngest
of these consists simply of a mucronate radicle, or initial point,
sometimes slightly dilated at its distal extremity (Fig. 21). When
further advanced the radicle is seen to be surmounted by an oval or
heart-shaped mass (Fig. 21 a), which, as a further step, becomes
gradually indented (Fig. 21 6), and is developed into the primary
cellules. When next seen the radicle is inconspicuous, and the
young form now difters from the adult in size only.
Another very common form, which is certainly referable to some
di-prionidian species, consists of a pointed radicle, terminating in, or
giving origin to, a solid axis, the lower part of which is embraced
by two semi-circular lobes, which are so arranged as to alternate
distinctly with one another, leaving the upper ‘part of the axis bare
(Fig. 22). When further developed, two additional lobes or cellules
are superimposed upon the first, the alternation being still main-
tained (Fig. 23).
Other germs, again, appear to belong to mono-prionidian species.
Like the last, these seem to commence simply as a pointed radicle.
In the process of development a delicate solid axis is produced from
the apex of the radicle, proceeding from one side of it, and not from
the centre. From the base of this axis, and also on one side only, a
small semi-circular lobe, or cellule, is developed, being applied
partly to the axis and partly to the radicle (Fig. 24). No more
advanced stages of these unilateral, or mono-prionidian, germs have
as yet come under my notice.
1 The first notice of these embryonic forms, as occuring in Britain, came, I believe,
from Mr, W. Carruthers, who described and figured a small germ, which he con-
sidered to be referable to his Diplograpsus tricornis, (See Annals and Magazine of
Natural History, Vol. iii. No. 13, p. 25),
Vol. LV Pt: VIL.
Ga)
zi |
oe aS
Det 6”
SILURIAN (GhArPT@ORIiiis,.
LOWER
Wyatt-Edgell—The Arenig and Llandeilo Groups. 118
EXPLANATION OF PLATE VII.
Fig. 1. Didymograpsus flaccidus (Hall. sp.), nat. size.
1a. Portion of the stipe of the same enlarged.
2. Portion of D. flaccidus, showing the radicle, with three small spines on the
opposite margin.
3. Another specimen, with a longer radicle.
4. Diplograpsus Whitfieldi (Hall. sp.), nat. size.
4a. The same, enlarged.
5. Diplograpsus mucronatus (Hall. sp.), nat. size. Introduced for comparison
with D. Whitfieldi.
5a. Portion of the same, enlarged.
6. Diplograpsus quadri-mucronatus (Hall. sp.), nat. size.
6a. Portion of the same, enlarged.
7. Enlargement of a portion of D. quadri-mucronatus, after Hall, showing
the two spines arising from each cellule.
8. Transverse section of the stipe of D. guadri-mucronatus, after Hall.
9. Corynoides calicularis (gen. nov.), nat. size. 9 a. The same, enlarged.
10. Ditto, with a single mucro. 11. Cup of Corynoides, enlarged.
12. Diplograpsus tubulariformis (n. sp.), nat. size. 12a. The same, magnified.
13, and 13 a. Ditto, in which the lateral cellules are reduced in number. (Fig.
13) nat. size, and (Fig. 13 a) enlarged.
14 and 14 a. Rounded variety of D. tubulariformis, in which the lateral cellules
are still further reduced in number. (14) nat. size, and (14 a)
enlarged.
15 and 15 @. Another variety of the same, in which only the terminal cellules
are left, nat. size, and enlarged.
16 and 16 a. Diplograpsus acuminatus, (n. sp.), ordinary form, nat. size and
enlarged. 16 4. Portion of stipe of the same, enlarged. 16 ¢.
Radicle of the same, enlarged.
17 and 17 a. Variety of D. acuwminatus, in which the cellules are rounded, and
very variable in shape, (D. angustifolius Hall.?) 17 6. Portion
of the stipe of the same, enlarged.
18. Didymograpsus anceps (n. sp.), with rudimentary radicle, nat. size.
18 a. Portion of the same, enlarged.
19 and 20. Ditto, without any apparent radicle, nat. size. 20 a. Portion of
stipe, enlarged.
21 and 21 @ and 4. Germs of Diplograpsus pristis, enlarged.
22 and 23. Germs of a di-prionidian Graptolite, enlarged.
24. Germ of a mono-prionidian Graptolite, enlarged.
V.—On tur ArEnic anp LiANDEILO Grovps.'
By the late H. Wyatt-Epcerrt, Esq., 13th Light Infantry.
ee lower strata of the Silurian system are, as yet, but little
known. The labours of Welsh and other geologists have
brought to light the large fauna of the Lingula flags; but while
the Upper Cambrian has thus been established and elucidated, the
beds which lie immediately above it, namely the “ Arenig group,”
and the Llandeilo flags, remain to be searched, and a great part of
the respective fauna of each to be described.
The Arenig, or Skiddaw, group of Sedgwick forms the base of the
true Silurian rocks; it immediately underlies the Llandeilo flags,
1 This paper (originally read before the ‘‘ Geologists Association,’ and published
in their Proceedings in July, 1866,) was handed to the Editor of the GronocicaL
MaGazirng, in the autumn of last year, by the Rev. E. Wyatt-Edgell, with a request
from his son (at that time in Ireland) that it should appear in this Journal. In
addition to the author’s own MS. corrections, the copy was obligingly corrected by
Mr. J. W. Salter, F.G.S.—Edit.
VOL. IV.—NO, XXXIII. 8
114. = Wyatt-Edgell—The Arenig and Llandeilo Groups.
from which it is totally distinct, although classed with them in
Murchison’s “‘Siluria.” The name is derived from Arenig-fawr,
Merionethshire, where the group is well shown and full of igneous
rocks: from this locality Prof. Sedgwick and Mr. Salter obtained
two of the characteristic fossils, Calymene parvifrons and Ogygia
Selwyniit. He recognized the beds as different from those above, and
called them Arenig slates, considering them the top of his Festiniog
group. (See “ Introduction 1o Synopsis of Woodwardian Museum,”
London and Cambridge, 1855.) But the group was not well known
as a distinct one, until the appearance of the last edition of Lyell’s
«Manual of Geology ;” since then it has been established more com-
pletely by the lists of fossils given in vol. iii. of the “Memoirs of
the Geological Survey.” In England it is seen in the lead-mining
district of the Stiperstones, Shropshire, underlying the Llandeilo
flags of Shelve and Cornden Hill; here it is that Murchison more
especially describes it under the name of Lower Llandeilo. It
occurs again near St. David’s Head, overlying the Cambrian, and
passing upwards into the Llandeilo flags; here it was first recog-
nized by Mr. Salter, who frequently cites this locality in his “ Mono-
graph of British Trilobites,” now coming out. (See Paleontogr.
Monogr.)
The distinctness of our group from the latter is evident when the
fossils of each are compared. The character of the fauna varies as
much as it does between the Llandeilo and the Caradoc—more so
than between the Caradoc and the Lower Llandovery. This will at
once be seen from the lists here given.
Arentc.—Ogygia peltata; O. Selwynii; Calymene parvifrons ;
Aiiglina binodosa ; Ah. grandis ; Af. caliginosa ; Trinucleus Murchi-
soni; T. Gibbsii; Orthoceras Avelinei ; Obolella plumbea; Orthis sp.
(Whitesand Bay) ; Cucullella Anglica ; Encrinites (two).
Lruanprrio,—Lowsr.—Asaphus tyrannus; A. peltastes; Ogygia
Buchii var. convexa ; Calymene Cambrensis ; Trinucleus favus ; Lichas
patriarchus; Bellerophon bilobatus ; Helicotoma sp. ; Lingula granu-
lata; L. attenuata; Orthis striatula ; Ctenodonta sp.
Lranprino,—Urrrr.—Asaphus Corndensis; O. Buchi, ordinary
var.; Barrandia (Ogygia) radians; B. Cordai; Calymene duplicata ;
Trinucleus fimbriatus ; Cheirurus Sedgwickw ; Ampyx nudus ; Agnostus
Maccoyi; Lingula Ramsayi; B. perturbatus ; Murchisonia simplex ;
Modiolopsis inflata ; Didymograpsus Murchisoni.
The first fossil cited from the Arenig is from Whitesand Bay,
near St. David’s Head. It has recently been described by Mr.
Salter under the name of Ogygia peltata; this description will be
published, I believe, in the next volume of the Palaontographical
Society."
Ogygia Selwynii, the next on the list, is the most characteristic
fossil of the Arenig, or Skiddaw, rocks. It is found both in the
Stiperstones district and in North Wales, and serves to mark these
beds, just as Ogygia Buchi does the Llandeilo flags. Associated with
1 This paper was written in March, 1866. The volume referred to, has since been
published. )
Wyatt-Edgell—The Arenig and Llandeilo Groups. 115
it is the remarkable Calymene parvifrons, first described from Tai-
hirion, near Arenig-fawr, but found since then in Shropshire.
Trinucleus Murchisoni is from Cefn-y-Gwynlle, one of the Stiper-
stone range of hills. Trinucleus Gibbsii is from Whitesand Bay. But
the most notable genus of this group is the singular trilobite A%glina,
of which there are other species besides the three here given.
Having but seven body-rings, no rostral shield, and a large lobe-
less tail, it is classed with the Asaphus family; but at the same
time the circular glabella and elongated eyes seem to connect it with
Remopleurides, one of the Olenide. It is eminently characteristic of
the Arenig period, where it attains its highest development; and
this genus may be looked upon as one of the patriarchs of Silurian
trilobites, for it seems to indicate a passage from the numerous
Olenide of the Upper Cambrian to the Asaphide of the succeeding
era. Represented by one or two species during the formation of the
Llandeilo flags, this genus fades away in the Caradoc. Of shells
there are but few species as yet described. The best known are the
Orthoceras Avelinet and Lingula or Obolella plumbea, which are not
uncommon in the black shales of the Stiperstones. The latter
species is the only one I know which is common to the Arenig
and Llandeilo; even this is doubtful, for the Obolella found at
Builth, and referred to this species, is not in every respect the same.
There is an undescribed species of Orthis found at Whitesand Bay ;
Cucullella Anglica from the Stiperstones, the Bryozoa Didymograpsus
geminus and Graptopora (Dictyonema) sp. ( ? socialis) Whitesand Bay
represent the inferior mollusca. 'Two species of Encrinites, the one
from Shropshire, and the other from the St. David’s district, com-
plete the lists of the more common fossils.
The Llandeilo series consists of two distinct strata, which I have
before proposed to call Upper and Lower Llandeilo flags, the latter
having nothing to do with the “Lower Llandeilo” of Murchison,
more properly distinguished by Sedgwick, as Arenig.
It is strange that the existence of two beds making up the
Llandeilo flags should never have been remarked before; for there
is as much difference between the subdivisions, both in fossils and
mineral character, as there is between the Upper and Lower
Llandovery, which it has been proposed to call even distinct groups
—not that, as a rule, the mineral character of beds is much of a
criterion for their classification.
I have long thought that the true ihndails ought properly to be
subdivided into two strata, but it was not until ‘lately that I saw
these occurring together, and so was enabled to determine which was
the higher, and which the lower member of the series. Near Builth,
in Radnorshire, there appear the Upper Llandeilo flags in the shape
of black shales and fine white sandstone, lying conformably on the
Upper Llandeilo, with the associated volcanic grit and bedded trap.
This is seen in the section (Sheet No. 5) published by the Geological
Survey, which crosses the shales and bedded trap of the Lower
Llandeilo at the Carneddau hill, and the grit, black shales, etc., re-
presenting the Upper Llandeilo near Wellfield.
116 Wyatt-Hdgell—The Arenig and Llandeilo Groups.
The Upper subdivision is also seen at Abereiddy Bay, Pembroke-
shire, in the form of dark slate, and black shale with graptolites.
(The two most common species found in this shale, viz. Didymo-
grapsus Murchisoni and Diplograpsus pristis, occur also at Builth,
where they mark the bottom beds of the Upper Llandeilo, just as
they do at Abereiddy. This fact may be of importance.)
The Lower subdivision, on the other hand, occurs as sandy flag-
stones with large beds of limestone at Llandeilo, also at Narberth,
Pembrokeshire ; often it contains trap and volcanic deposits (men-
tioned before). In a section near Llandeilo, published in “ Siluria”
(p. 57), the Lower Llandeilo is made to overlie what I suppose is
the Bala limetone of Bird’s Hill. Perhaps it is faulted against it.
Besides the one near Builth made by the Geological Survey, there
is a section of the whole Llandeilo group near Llangadock published
in “Siluria” (p. 58). Here the Upper Llandeilo, full of ‘Graptolites,
is represented by shales thrown up into an anticlinal over the Lower,
seen as bedded trap, flags, and limestone.
The charaeteristic fossil of the whole Llandeilo series is undoubt-
edly Ogygia Buchii. It is, however, of a greater size and commoner
in the upper subdivision; in the lower it is represented by a
smaller and more convex variety, with but eleven side-ribs to the
tail. his variety was recognized by Mr. Salter some time since,
and the name convexa was proposed for it.
Asaphus tyrannus and the nearly allied Asaphus peltastes are found
everywhere in the Lower Llandeilo, associated with the variety of O.
Buchit just mentioned. These, with Calymene Cambrensis and Trinu-
cleus favus, are fossils quite peculiar to this zone, not found in the
upper subdivision. Lichas patriarchus is a new species, of which
my description was published in the Gronocican Macazine for
April, 1866, Vol. IIT. p. 160. The Ophileta or Helicotoma, mentioned
in the list, is from Fairfach, near Llandeilo. Lingula granulata is a
characteristic fossil of this stratum. Orthis calligramma is found in
the volcanic grit near Builth, and Orthis striatula at Llandeilo and
Narberth. Associated with Asaphus peltastes, is a small Ctenodonta,
not uncommon in the limestone of Dynevor Park, Llandeilo; this
completes the list of the common fossils from the Lower beds.
The genus Asaphus is represented in the Upper Llandeilo by the
A. Corndensis' of Murchison, which is common at Gilwern, near
Builth. This is the only species that I know of. The large many-
ribbed variety of O. Buchit is eminently characteristic; curiously
distorted specimens of it are found in the slates of Abereiddy Bay.
The genus Barrandia, of which there will be four described species
when the next volume of the Paleontographical Society appears, is
peculiar to this zone. Calymene duplicata is a common fossil, and
everywhere accompanies the ordinary variety of O. Buchit. Chetru-
1 Asaphus Corndensis belongs to the subgenus Ptychopyge of Angelin, which has
certainly more the appearance of an Asaphus than of an Ogygia. ‘The form of the
labrum seems too variable in the Asaphide to be considered a generic distinction.—
H.W.E.—(See Mr. H. Wyatt-Edgell’s paper ‘‘ On the Genera Asaphus and Ogygia,
&c.” GroLocicAL Macazing, January, 1867, Vol. 1V. p, 14.—Eprr.) ;
Paleontology of Asia Minor. 117
rus Sedgwickii, Barrandia Cordai, Agnostus Maccoyi, Ampyx nudus,
and Trinucleus fimbriatus are found both at Builth and Abereiddy ;
Trinucleus Lloydii at Builth and Llangadoc.
Of shells, Bellerophon bilobatus is found both in this subdivision
and the lower one. Abundant in the Caradoc, this shell lived mto
the Lower Llandovery period. 2B. perturbatus occurs in the slates
of Abereiddy. A gasteropod, Murchisonia simplex ?, has lately been
found at Percerrig, near Builth.
From the same locality I have seen specimens of a Lingula very
like Lingula plumbea, Lingula Ramsayi is a common fossil at Abe-
riddy Bay; and a species of Modiolops/s, called M. inflata by M’Coy,
represents the lamelli branchiate shells.
The notes on the Llandeilo flags that I have here brought before
the notice of geologists were made during a tour in South Wales. I
will add that I think it more than probable that if the group be
carefully examined in Shropshire and North Wales, the same dis-
tinction will be found to exist between the Upper and Lower subdi-
visions of it.
INO GES aS) jC) IMsntiiVeOieS
——_@—__
I. Patmonrotocy or Asta Mrnor.
Aste Minevre. Description physique de cette contrée, par P. de Tchihatcheff.—
Paléontologie, par A. D’ Archiac, P. Fischer, et E. De Verneuil. 8vo. Paris, 1866.
Ouvrage accompagné d'un Atlas grand in 4io, 18 plates.
HE geological portion of this work, to be completed in two
volumes, by M. de Tchihatcheff, was intended to have been
issued at the same time with the Paleontological portion, but the
latter having been completed first, it was thought desirable to
publish it at once, as a delay of even a few months might have been
very prejudicial to it. The Geology is expected to-be published in
the course of the present winter.’
An introductory chapter on the ‘‘ General Paleontological Results”
is given by M. D’Archiac, who prefaces it with a historical sketch of
the labours of previous investigators into the geology of this region,
from the times of Strabo, Aristotle, and Theophrastes, until when,
towards 1835, it was first scientifically explored by Messrs. Hamilton
and Strickland, Spratt, Edward Forbes, Ainsworth, and Ch. Texier.
Devonian, Cretaceous, and Lower and Upper Tertiary formations
occupy the greatest geographical area; Jurassic and Carboniferous
strata have only been observed in a few and very restricted localities,
while rocks of Silurian, Permian, and Triassic age have not at
present been determined. Quaternary deposits are spread over
the country in many places.
Dervontan.—Beds characterized by fossils, mostly belonging to
the Lower Devonian of Western Europe, are found in the North;
1 Since writing the above the first volume of the ‘‘Geology’”’ has been published ;
we shall notice it in a future number of the Grotocican MaGazine, after the issue
of the second volume.
118 Paleontology of Asia Minor.
among the species are :—Homalonotus Gervillei, Rhynchonella Gueran-
geri, Spirifer macropterus, S. subspinosus, S. Davousti, Orthis orbicularis,
Chonetes sarcinulata, C. Boblayei, and Pleurodictyum problematicum
Two species, Orthis Gervilliei and Tentaculites ornatus, are Silurian
forms.
In the South, the presence of Rhynchonella boloniensis, Spirifer
Archiaci, S. Seminoi, Chonetes nana, and Productus subaculeatus, would
seem to indicate rocks of Upper Devonian age.
Of the 49 Devonian species, 37 are found in the rocks of the
North, and 21 in those of the South.
CARBONIFEROUS.—The Carboniferous, like the Devonian formation,
is developed in two widely distant localities, each of which presents
a distinct horizon.
In Anti-Taurus (E.), have been found Productus semi-reticulatus,
P. Flemingii, and Spirifer ovalis, which, though a very scanty fauna,
suggests the representative of the Carboniferous Limestone ; and on
the shore of the Black Sea, in Paphlagonia, are coal-strata, which
have yielded Lepidodendron caudatum, Sigillaria Candollei, 8. Schlo-
theimit, Stigmaria ficoides, Calamites Suckovit, and C. dubius.
Jurassic.—Four species of Ammonites (A. tortisuleatus, arduen-
nensis, plicatilis, and tatricus), discovered in the grey limestones of
Galatia, seem to indicate an extension of the Oxford-Clay horizon,
which is one of the most constant of the Jurassic formations.
Cretacrous.—Yellow limestone, in the Province of Pont, with
Orbitoides, Pecten quadricostatus, Exogyra Pyrenaica, Ostrea vesicularis,
O. larva, and Otostoma, represent the Upper Chalk of the West of
Europe, and their identity, both zoologically and lithologically, with
beds in the same parallel at the foot of the Pyrenees, is remarkable.
White limestones, in Bithynia, with Inoceramus Lamarcki, Ananchytes
ovata, and Terebratula semiglobosa, represent the white Chalk. The
presence of Rudistes denotes the constancy of that zone.
Trertrary.—Lower Tertiary.—The white and grey limestones of
Thracia, Paphlagonia, and Cappadocia have furnished 164 species of
Invertebrata, of which nearly half have also been found in the Lower
Tertiary Deposits of Western Europe, and intermediate points.
A Crustacean (Ranina Tchihatchefft) represents a type constant at
this level in Europe, and probably also in Egypt and in India, as well
as in the West Indies. ‘T'wo large species of Cerithium are met with,
but no small specimens. The absence of species of Fusus with pro-
longed canals, of Pleurotoma, Turritella, Buccinum, Murex, and the
rarity of Voluta and Mitra, are noteworthy facts. The principal
gasteropods are Terebellum, Ovula, Natica, Sigaretus, Hipponyx, and
Phasianella.
The bivalves constitute a striking analogy with those of Hurope.
Bryozoa are extremely rare; Hchinodermata less so; a few species
of Corals have been met with at some localities.
Thirty-eight species of Rhizopods occur, one only of which (Num-
eae Viquesneli) is peculiar; 25 species of this genus have been
ound,
Middle Tertiary.—Deposits of this age occur on the borders of the
Meek—On Bellerophon. 119
Mediterranean (South Coast). 116 species of Invertebrata have been
determined, but their examination does not point to any particular:
horizon in Europe. 72 of the species are also found in Touraine,
Aquitaine, Languedoc, Provence, Italy, the Vienna Basin, and Ger-
many. Bryozoa are rare. Among the Corals are 5 species of Heli-
astrea, and of the Rhizopods, 2 species of Operculina predominate.
Seven species of plants (Monocotyledonous Phanerogams) have been
determined, whose analogues are already known in the Middle Ter-
tiaries of Styria, Croatia, and Switzerland.
Tertiary Lacustrine Deposits of different ages occur; the fauna of
the whole comprise 33 gasteropods and 6 acephala; forms identical
or closely related, are still living in the Hast.
QUATERNARY.—The absence of all vertebrate remains in these
deposits renders their precise age uncertain; they do not however
appear to be of very great antiquity. Many microscopic organisms
occur, among which are many Navicule and Pinnule. All these
deposits are believed to be freshwater.
The above observations are translated from M. D’Archiac’s Intro-
duction, and we may add that the Paleozoic Fauna is described by
M. De Verneuil, and the Flora by M. Ad. Brongniart; the Secondary
and Lower Tertiary Fossils are described by M. D’Archiac; the
Middle Tertiary Fauna by M. Fischer, and the Flora by Dr. Unger ;
the Upper Tertiary and Quaternary Fossils, by M. Fischer.
i H. B. W.
iJ.—Nore on THe AFFINITIES OF THE BeLLEROPHONTIDZ. By F.
B. Mrex.
[Proc. Cutcaco Acap. Sciences. Vol. I., 1866.]
HE family Bellerophontide (of McCoy) includes a most interesting
group of extinct shells, almost, if not entirely confined to the
Paleozoic rocks. If we exclude the little Cretaceous genus Bellero-
phina (the relations of which to this group may be at least regarded
as very doubtful), and include Porcellia, the range of the family
will be from the Lower Silurian to the Trias.
Mr. Meek recounts the various opinions in regard to the affinities
of this ancient type of Mollusk, entertained by Von Hupsch,
Montfort, Defrance, D’Orbigny, McCoy, Deshayes, De Koninck, and
others. In 1844, Prof. De Koninck, who viewed these shells as
Gasteropods, placed them in the Scutibranchiate order of the Proso-
branchiata—regarding them as Emarginule, with a greatly extended,
and strongly involuted apex.
In 1864 a new fossil genus, Tremanotus, was described by Prof.
Hall, and placed as the type of a sub-genus under Porcellia, but
such a striking resemblance does it bear to Bucania, that Mr.
Meek is of opinion that it should be placed under that genus;
it only differs from it in the peculiar and interesting character of
having along the middle of the dorsal side a row of isolated,
oval siphonal openings; while it differs from Porcellia, not only
in that important character, but in the greater thickness of the
120 Reviews—Lyell’s Principles of Geology.
shell, and its strongly dilated mouth. And, from the fact that the
genus Bucania is so nearly allied to Bellerophon that few Paleon-
tologists regard it as generically distinct, it must be manifest that
these three types must go together, wherever we place them. Now
as there are no examples, so far as known to the author, of a shell
with isolated siphonal openings, except amongst the Prosobranchiate
Cephalopoda,—for instance, the Haliotide, Fissurellide and Pleuro-
tomariade—it indicates, for the family, a position near the Fissurellide
and Haliotide, and between these groups and the Plewrotomariade.
ae Vi EeVVisSe
1.—Principtes or GEOLOGY, oR THE MopEerN CHANGES OF THE
EARTH AND ITS INHABITANTS, CONSIDERED AS ILLUSTRATIVE OF
Grotocy. By Sir Cuarites Lyrrt, Bart.. M.A., F.R.S. 10th
and Entirely Revised Edition. In two vols. Vol. I. TIllustrated
with Maps, Plates, and Woodcuts. London, Jonn Murray, 1867.
F all the Books upon the natural sciences, written within the
present century, we may safely affirm that none have had so
great an influence upon any particular subject as has Sir Charles
Lyell’s “ Principles” upon the progress of geology.
Tn evidence of the avidity with which the teachings of this great
master have been received, we need only state that from its first
appearance in January 1880, to June 1858, the ‘‘ Principles of Geo-
logy ” had run through nine editions, and it had, by 1838, become
the parent of another work, now equally well known, “The Ele-
ments of Geology.” This thriving child of so good a stock arrived
last year at its sixth edition. And, this year, Volume I. of its
parent’s Tenth Hdition was cut by many an anxious inquirer after
truth. Nor is this all the family with which Sir Charles Lyell’s
“Principles” has been blest ; for, in 1863, he issued another most
welcome volume, entitled the “ Antiquity of Man,” which enjoyed a
privilege (shared by few efforts of penmanship, we imagine.) of
three editions in one year. Liyell’s “‘ Principles” has been so often
reviewed, that it is unnecessary to do more than notice some of the
more important additions and modifications which one would expect
to find in it, as nearly fourteen years have elapsed since the publi-
cation of the last edition. That consisted of one volume of 885
pages, whereas the first volume of this new edition contains in itself
no less than 671 pages. The actual increase, as regards corres-
ponding chapters in the last edition is about 275 pages, but a part of
this is due to the use of larger type.
The chapter on the progressive development of organic life has
been entirely re-written. In speaking of the introduction of man,
the author states that “little or no progress has been made in dis-
covering fossil remains which indicate any inferiority in the cerebral
development of man in the paleolithic era.”
A new chapter on the proofs of former vicissitudes in climate,
{
Reviews—Lyell’s Principles of Geology. 121
derived from the study of the Secondary and Primary fossiliferous
formations, has been added. In it the author discusses the theory of
an excess of carbonic acid in the air during the Coal-period. He
regards as delusive, inferences deduced from the fact, that there is ten
times more carbon in a solid form in the ancient Coal-measures than
is now contained in the atmosphere. The atmosphere now
receives large supplies of carbonic acid, by gaseous emanations from
the interior of the earth; but, wherever peat is forming, the process
is seen by which carbon is first extracted, by the powers of vegetation,
from the atmosphere. Mr. Darwin attributes the small quantity of
peat formed in parts of South America to the absence of species of
plants fitted for its production. The abundance of coal, therefore,
in certain districts may have arisen from the peculiarity of the vege-
tation, and of a climate which retarded decomposition, rather than
from any peculiarity in the atmosphere which enveloped the globe in
the Carboniferous period.
In a special chapter the author has considered how far former
vicissitudes in climate may have been influenced by astronomical
changes, such as variations in the eccentricity of the earth’s orbit ;
changes in the obliquity of the ecliptic, and different phases of the
precession of the equinoxes. Mr. Croll’s suggestion as to the pro-
bable effects of a large eccentricity in producing glacial epochs is
fully discussed, and the question is entertained whether geological
dates may be obtained by reference to the combined effect of astro-
nomical and geographical causes.
In the chapter on the phenomena of Springs, the author notices
the discovery of live fish in some artesian wells, sunk in the Sahara.
They were brought from a depth of 175 feet, and were not blind,
like those of Adelsberg, but had perfect eyes.
The antiquity of the delta and alluvial plain of the Mississippi is
discussed, with reference to new facts brought to light during the
survey of Messrs. Humphreys and Abbot. Sir Charles had esti-
mated that the accumulation of the whole delta-deposits must have
taken 67,000 years; but the former gentlemen, in the course of
their survey, came to the conclusion that the quantity of water
annually discharged by the Mississippi, had been greatly underrated ;
consequently the number of years required for the growth of the
whole delta would be reduced to about one-half, or to about 338,500
years. In the same chapter are discussed the researches of Mr.
W. H. Bates and Professor Agassiz on the delta of the Amazous, and
of Mr. Fergusson on that of the Ganges.
A chapter on the action of tides and currents, contains an account
of Captain Spratt’s observations in the Mediterranean. His survey
shows how different parts of an inland sea, and the adjoining ocean,
may have different temperatures at a moderate distance from the
surface, in consequence of submarine barriers. The range of aquatic
species inhabiting the waters at various depths must evidently be in
no small degree dependent on such continuous submarine ridges.
An illustration of the stone-capped earth-pillars of Botzen, in the
Tyrol, adorns the cover. Itis from a drawing by Sir John Herschel,
122 Reviews —The Paleontographical Society's Monographs.
and is also introduced, as a woodcut in the letter-press, to show the
distinction of the power of rain from that of running water.
IIl.—Monocrarus PUBLISHED BY THE PALMONTOGRAPHICAL SOCIETY :
Vou. x1x. 1866.
HIS fasciculus of Monographs, and parts of Monographs, is
supplied to the members of the society as the volume due for
1865; thus, the issue of annual volumes is now only one year
behindhand. This volume comprises:—1l. Part of a Monograph of
the Foraminifera of the Crag, by Messrs. Jones, Parker, and Brady.
2. Part I. of Dr. Duncan’s Monograph of the British Fossil Corals ;
second series. 38. Portion of Mr. H. Woodward’s Monograph of the
British Fossil Merostomata (Pterygotus, etc.). 4. Part VII. No. 1, of
Mr. Davidson’s Monograph of the British Fossil Brachiopoda.
Thirty-five plates richly illustrate the numerous fossils described in
this volume.
The first of the Monographs, above-mentioned, is concerned with
a group of organisms, extremely abundant in the fossil, as well as
in the recent state, but which had not hitherto been the subject of
any of the Palezontographical Society’s Monographs. We not only
welcome this memoir, but rejoice to see that there is an intention to
give the Cretaceous, and the Liassic Foraminifera also, a place in
this fine repertory of British Fossils, according to the Society’s List
of Monographs in Preparation.
To those who have a definite notion of the value these low-classed
and variable Microzoa have in paleontological geology, the Intro-
duction to the Monograph of the Foraminifera of the Crag will
afford good data for conclusions, in its concise account of the groups
peculiar to the several zones of the Crag; and the Monograph itself
(as far as itis brought out) evidently aims at supplying the zoologist,
as well as the geologist, with both special and general information
about these minute shells, supplementing to a great extent, the
elaborate and broadly treated description of the Arctic and Sub-
arctic groups of recent Foraminifera, by Messrs. Parker and Jones,
in the “ Philosophical Transactions” of 1865, to which this Mono-
graph makes frequent reference, The bibliography and comparison
of the so-called genera and species appear to have been especially
cared for; and the results are remarkable, both, in the long lists of
synonyms, such as could only be offered to the public in the works
of a Society, and in the bold and systematic compression of numerous
individual and varietal forms around very few types. After all, in
the elaborate lists, showing relationship, distribution, and relative
abundance and size, 102 species and noticeable varieties are enu-
merated as having been found in the Crag of Suffolk, chiefly by
Mr. Searles Wood, whose name is indissolubly associated with the
Crag and its fossils.
Dr. Duncan offers his Monograph on the Fossil Corals as a
Supplement to the great Monograph by Messrs. Edwards and
Reviews—The Paleontographical Society's Monographs. 123
Haime; and he prefaces it with an “Introduction,” comprising a
clear, concise, and systematic account of the anatomy, reproduction,
physiology, and classification of the Recent, Tertiary, and Secondary
Stony Corals, based on the works of Edwards and Haime. The
exactitude with which the essential characters of the fossil Corals are
here pointed out, and distinguished according to a definite termin-
ology, will be thankfully recognised by many a naturalist and
geologist. Several new Tertiary Corals, chiefly from Mr. F. Kdwards’s
collection, are fully and methodically described, in strict, technical,
and therefore unmistakeable language.
Mr. H. Woodward also stamps his Monograph on the Pterygotus,
Hurypterus, and their allies, with exactness of terminology, com-
pleteness of classification, and fullness of bibliographic history; and
all this will be of great use in the further progress of his Monograph,
of which only a small portion now appears.
The laborious and conscientious care in working out the history
and relationships of the known British Silurian Brachiopods, for
which Mr. Davidson’s Monograph is remarkable, is characteristic of
that paleontologist, as is well known. by those who have gone
through his other Monographs,—or rather, the other Parts and
Volume of this his great Monograph of the British Brachiopoda.
The obscure specimens from Silurian slates, schists, and other
squeezed, distorted, and altered strata, have passed, like hieroglyphic
cartouches and semi-defaced medals, from dynasty to dynasty, from
name to name, until the care and erudition of one enthusiast have
been brought to bear on all and each, definite notions of their real
alliances have been settled, and perfect illustrations of all the series
made visible on one set of plates. The loving care with which every
feature in shape and ornament, wrinkles, pimples, network, etc.,
have been delineated by Mr. Davidson himself, in these twelve
plates (part only of the Silurian series), is testified plainly. The
painstaking research, and reproduction of everything worth record-
ing that the various authors have written about the specimens
whereon they founded the species that Mr. Davidson treats of, is
only equalled by the good sense, caution, and perspicuity of his
descriptions. Besides its own Bibliographic Introduction, the Mono-
graph is preceded by a “Classification of the Silurian Rocks,” by
Sir Roderick Murchison—heing a succinct account of the history of
discovery, and order of sequence, from that eminent geologist’s own
point of view.
As very many must necessarily value the Monographs, published
by the Paleontographical Society, for the illustrative figures, as
much as for the descriptions, we feel called on to remark that there
is no falling off in the drawing or printing of the plates. George
West has given the Foraminifera, in his plates, a real natural aspect,
that no high-finished artificiality of the mere lithographer can attain
to. Mr. De Wilde has evidently succeeded in mastering the features
and structure of Corals. Mr. Fielding’s Pterygoti are boldly, care-
fully, and naturally drawn. Lastly, Mr. Davidson’s Brachiopods
are wonderful reproductions of the original specimens, and of their
124 Reviews—Geological Society's Journal.
details, enlarged; and with them are several copies of sketches by
former observers, to complete the history of the whole.
I1.—Tue Quartrerty JouRNAL oF THE GxEoLoGicAL Socrmry, Vol.
XXIII. Part I. (No. 89, February 1, 1867.)
OSMOPOLITAN, as usual, the Geological Society’s Journal
comprises memoirs and notices of facts from many parts of
the world. First, Professor Huxley describes some bones of large
Dinosaurian Reptiles, from South Africa. The Huskelesaurus, so
called, because he had good legs to stand on, had a femur nearly
three feet long ; another such reptile is termed the Orosaurus. Both
are from “Mr. Bain’s Stormberg Beds,” of the Stormberg, near
Aliwal, and probably higher in the geological series than the Karoo
beds, with Dicynodonts. Second, From Australia, the Rev. W. B. Clarke
sends an account of all the fossils of Secondary Age (Jurassic), that
he has seen or heard of; and, in a postscript to his paper, he adds
further evidence of Glossopteris Browniana being really Paleozoic.
Third, Dr. Duncan, chiefly by means of a fine series of corals
collected by Mr. Charles Moore, in South Wales, compares the beds
beneath the Lias in Britain, with their equivalents elsewhere,
and defines them as the “ Infra-lias,” divided into—a. (Upper), the
Southerndown, Sutton, and Brocastle limestone, etc. ; 6. (Middle),
Ammonites-planorbis Zone, etc. ; c. (Lower), Avicula-contorta, or
Rhetic series. It is a pity to see, throughout this memoir, on the
Infra-lias Coals of South Wales, the word ‘“ Astrocoenia”’ mis-spelt.
Fourth, Mr. H. Woodward follows with a bibliographic, classifica-
tory, explanatory, and descriptive paper on the Xiphosures—that is
Limulus, Belinurus, Hemiaspis, Bunodes, Pseudoniscus, HExapinurus,
and anew genus Prestwichia ; their relationship to Hurypterus and
Pierygotus is especially treated of. Fifth, Dr. Duncan describes
some Cretaceous Echinoderms brought from Mount Sinai, by the
Rev. H. Holland. Sixth, Mr. Hawkshaw, on the geology of a part
of Egypt. Seventh, Mr. J. Curry, on the Drift of the North of
England, gives useful facts. Eighth, Mr. J. W. Flower has found,
near Thetford, in Norfolk, some prehistoric flint instruments of the
same form and fashion as some from St. Acheul, in France, as the
great ugly woodcuts strongly show. 9. Lastly, (excepting some
miscellaneous matter), Professor Williamson describes a well-
fieured Cheirotherian foot-print from Cheshire, which shows evident
marks of a true scaly skin.
In this varied group of observations many will find much to learn,
and with regard to “ Homotaxis,” in particular, the reader will find
materials for grave consideration.
IV.—Merrorirms, Abrorites, AnD Fauuine Srars. By T. L.
Puirson, Dr. Sc. &c. 8vo. pp. 240, 1866. London: Lovell
Reeve and Co.
P\HE author of this little work has endeavoured to bring together,
in a popular form, the latest observations that tend to explain
Reviews—Phipson’s Meteorites. 125
the phenomena of shooting stars. The various terms in use for
these bodies, such as meteors, fireballs, falling stars, meteorites, etc.,
he considers to be identical meteoric phenomena, only seen under
different circumstances, and from different positions.
The attention of meteorologists, mineralogists, and other men of
science, was first directed to this subject by Chladni’s treatise on the
probably celestial origin of the mass of iron discovered in Siberia by
Dr. Pallas. This treatise was first published in 1794, and two
months after his views received a remarkable confirmation, by the
fall of a shower of stones at Siena, in Italy, on the 16th of June,
1794. Between the years 1794 and 1802 three other well-observed
falls took place, and in this latter year, the first analysis of an
aérolite was made by Luke Howard, and published in the Phil.
Trans. of the Royal Society. Descriptions of the fall of all the most
important aérolites are briefly given, together with analyses of
many of the stones, which exhibit the similarity in composition
of these bodies. The various theories proposed to account for these
phenomena are also briefly described. Had the author procured
a later edition of the “Catalogue of the Meteorites in the British
Museum,” than that published in December, 1868, for his compila-
tion, he might more correctly have represented its present condition.
There have been at least three, if not four, editions of this cata-
logue published since December, 1863, the last of which bears the
date October 1st, 1866, and shows the collection to contain 350 speci-
mens, representing 236 distinct falls. Among several other similar
inaccuracies we select the following :—Of the great fall at L’Aigle,
Normandy, on the 26th of April, 18038, he states, ‘‘ A specimen,
weighing two pounds two ounces, may be seen in the British Museum.
The catalogue says, nine specimens weighing 5 lbs. 2 oz. 260 grs.
Again, of that of Chantonnay, La Vendée, France, he says, ‘ There is
a sample weighing one pound four ounces, in a collection at the
British Museum,” whilst the catalogue states that there are three
specimens of the collective weight of 2 lbs. 15 oz. 287 grs., or nearly
three pounds. Also, at page 191, referring to the remarkable fall at
Butsura, India, we read, ‘“‘ Five meteoric stones, which fell on the
12th of May, 1861, near Gootka, in India, and weigh together up-
wards of thirty pounds, being joined together by their uncoated sur-
faces, fit so exactly into one large uniformly crusted mass, that,
according to Mr. Herschel, two fragments only are wanting at the
angles; and these five stones were found from two to four miles
apart.” This description is certainly a very loose one. The weight
of the whole, when found, exceeded fifty-one pounds ; the total weight
of the parts, now in the British Museum collection, according to the
catalogue before quoted, is 41 lbs. 18 oz. 187 grs. The other por-
tions of this aérolite are deposited in the Calcutta Museum. From a
very interesting paper on this fall, by Professor Maskelyne, in the
Philosophical Magazine for January, 1868, which Dr. Phipson does
not appear to have consulted, and from the specimens and models
themselves, it will be seen that but three of the fragments had un-
coated sides. That which fell at Bulloah, was broken into four or
126 _ Reports and Proceedings.
five pieces on striking the ground, only two of which were saved,
and one side was not coated, viz., that which fitted the uncoated side
of the Piprassi specimen. The remainder of the fractured surfaces
are perfectly crusted, but not uniformly, as it is thicker on the origi-
nal surface than on the fractures. This fall is most instructive. It
is one of the few recorded cases of disrupted fragments of an aérolite,
travelling a considerable distance through the earth’s atmosphere,
without fusion taking place on the disrupted sides.
At the end of the book a list of public and private collections is
given. The collection of R. P. Greg, Esq., of Manchester, has been
disposed of, and is now deposited in the Museum at Calcutta. The
weight of the larger of the two masses of meteoric iron found at
Cranbourne, near Melbourne, Australia, which is exhibited in the
British Museum, is about 8,200 pounds, or over 3 tons 13 cwt. The
smaller mass was exhibited in the International Exhibition for 1862,
before being deposited in the National Collection, but was soon after-
wards sent back to Australia in exchange for the larger one.
In Chladni’s useful catalogue of recorded falls of aérolites, pub-
lished in vol. xxxi. of the “Annales de Chimie et de Physique,” 1826,
we find the following :—“ 1680, 18 Mai Pierres a Londres, King.”
Dr. Phipson has quoted this, and, in a foot-note, remarks that he has
not been able to procure a copy of Mr. Edward King’s work, which
is entited—‘ Remarks upon Stones said to have fallen from the
Clouds.” This book is in the library of the British Museum, and
the stones referred to by Chladni, as having fallen in London, were
hailstones! We give Mr. King’s own words: “On the 18th of
May, in the year 1680, some hailstones are recorded to have fallen
in London, near Gresham College; which were seen and examined
by the celebrated Dr. Hooke ; and were some of them not less than
two inches over, and others three inches.” It is a pity Dr. Phipson
did not expend more care in the production of this little book; but
we must accept it as, at present, the only work giving a general
résumé of the origin, progress, and present state of aérolitic know-
ledge. A really good book upon this subject would indeed be
welcome, at a time when the interest excited by the wonderful
“< Star-shower” of November last has not yet ceased.
RBEHEPORTS AND PROCHEDINGS:
ee
@notogrcat Socrery oF Lonpon.—I. January 23, 1867.—
Warington W. Smyth, Esq., M.A., F.R.S., President, in the chair.
The following communications were read :— «
1. “On the. occurrence of Consolidated Blocks in the Drift of
Suffolk.” By George Maw, Esq., F.L.S., F.G.S.
As a contribution to the evidence on the geological position of the
blocks of saccharoid sandstone scattered on the surface of many
parts of the Chalk-districts, which appear to have been derived from
several formations of different ages, the occurrence was recorded of
large isolated masses of consolidated sand and gravel in the Drift
Reports and Proceedings. 127
intervening between the Chalk and Boulder-clay of the high ground
of Suffolk. Many of the masses are several tons in weight. Although
they occur at a general level they do not form a connected band ;
loose Drift, out of which they were evidently composed, forming a
horizontal continuation of their strata. ‘The drift is largely charged
with Chalk-detritus, which also occurs in the softer blocks; some of
the blocks are extremely hard and compact, and in these the sandy
agelomeration seems to have given place to a crystalline structure ;
but the hardest of those found in situ were resolvable into sand by
the action of hydrochloric acid, and appeared to be merely held to-
gether by a calcareous cement.
A block resting on the Red Crag near Woodbridge was found, on
analysis, to contain no lime, excepting a small quantity in the form
of silicate.
The springs in the gravel-bed at Crowfield, near Coddenham, are
chalybeate, containing in solution Lime and Iron, which are precipi-
tated on standing, and much carbonic acid is evolved from a well
sunk through the gravel; the author considered that the carbonic
acid may have been the solvent agent in forming the calcareous cement,
and that the first stage of the consolidation of the blocks of saccha-
roid sandstone may have been by the agency of calcareous matter ;
and he referred to the possibility of lime in solution, when in con-
tact with silica, giving rise to silicate of lime, a very small propor-
tion of which would form a powerful cement in agglutinating
siliceous particles together.
2. “ Notes on some Chemical Analysis of variegated Strata.” By
George Maw, Hsq., F.L.8., F.G.S.
The author gave the results of some analyses for the determination
of Iron in the light and dark parts of variegated Slates, Sandstones,
and Marls, the colour of which is due to oxide of iron, and in which
the variegation appears to be disposed independently of mechanical
arrangement. The analysis in each case exhibited the fact that the
lighter blotches, spots, and stripes contained a smaller portion of the
colouring oxide than the average mass, a proportion which implies
an actual difference in the percentage of the metallic iron, and
which could not be accounted for by any mere difference in the state
of its combination. This shows an actual departure of a part of the
colouring oxide out of the colourless patches, and a dispersive pro-
cess which seemed to be the very reverse of the segregation of no-
dules of Carbonate of Lime and Carbonate of Iron out of a clayey
matrix. Among the forms of variegation referred to were: (1st)
that resulting from the segregation of dark blotches out of a lighter
matrix, the evenness of colour of which does not appear to have been
materially affected by the withdrawal of a part of its colouring-
matter; (2nd) that resulting from the segregation of dark blotches
out of a lighter ground, each of which is concentrically surrounded
by a distinct and well-defined zone lighter than the general ground ;
(8rd) strata variegated with light blotches containing a smaller pro-
portion of colouring-matter than the general ground, but not ar-
ranged concentrically round a darker nucleus; (4th) the variegation
128 Reports and Proceedings.
of coloured strata with both light and dark blotches, containing re-
spectively a smaller and larger proportion of the colouring oxide
than the general ground, but which are not arranged, as in the 2nd
case, concentrically with each other.
The following specimens were exhibited :—
Examples of “variegated slates, marls, and sandstones; fragments
of consolidated blocks from the Drift of Suffolk; and of Sarsen
stones, from Avebury, Wiltshire; Upper Tertiary fossils collected
by the Rev. C. Mozley in Iceland; and two Flint Implements from
Canada; exhibited by George Maw, Hsq., F.G.S., ete.
Hardened Chalk and Drift from Hertfordshire ; ; exhibited by W.
Whitaker, Esq., B A., F.G.S.
Specimens of Staffellite from N. assau; exhibited by H. Buerman,
Esq., F.G.S.
Warington W. Smyth, Esq., M.A., F.R.S., President in the Chair.
The following communications were read :—
1. “On the Jurassic Fauna and Flora of South Africa.” By
Ralph Tate, Hsq., F.G.S.
In this paper the author gave descriptions of the undescribed
fossils in the Society's Museum, obtained from the following
secondary deposits of Cape Colony, in ascending order :—
(1.) Karoo Beds.—These strata, containing Dicynodon and Iridina,
have yielded a flora which was stated to present close analogy with
the plants of the Coal-formations of Burdwan and Nagpur, India,
and the Newcastle Coal-field, New South Wales. The characteristic
plant in each of these deposits, and in the Karoo Beds, is a Gloss-
opteris. ‘The author regarded the age of the Karoo Beds, from
their position and organic contents, as approximating to that of the
Trias ; and he described from them species of the following genera :
—Glossopteris, Phyllotheca, Dictyopteris, Rubidgea, n. g., and Ather-
stonea, n. &
(2). Phytiferous Beds of Geelhoutboom.—The flora of this deposit is
characterized by the presence of Palgozamia, Arthrotaxites, Asple-
nites, Pecopteris, Sphenopteris, and Cyclopter’s, several species of
which are comparable with certain others from the Oolitic series of
Europe, and of the Rajmahal Hills, India. One species, Asplenites
lobata, Oldh., is common to South Africa and India.
(3). Marine Limestones, etc., of Port Elizabeth Province.—The great
mass of the fossils from this series are bivalves; and the extreme
rarity of Cephalopoda, Polyzoa, Echinoderms, and Corals, was stated
to call to mind the conditions of life which prevailed during the
deposition of the upper members of the Lower Oolites in England.
The generic grouping is such as occurs in the Jurassic series; and
though no genus represented in the South African fauna is peculiar
to the Jurassic rocks, yet the following give a marked Oolitic facies
to them: Belemnites (Canaliculati), Actzonina, Alaria, Neritopsis,
Pleuromya, Placunopsis, Isastrea, etc. Four species were referred to
European forms, viz., Trigonia Cassiope, d’Orb., T. Goldfussi, Ag.,
Reports and Proceedings. 129
Serpula filaria, and S. plicatilis; but a very large number of the
African shells have their representatives in the Lower and Middle
Oolites of Europe, and their equivalents in India.
2. “Further remarks upon the relation of the Chillesford Beds to
the Fluvio-marine Crag.” By the Rev. O. Fisher, M.A., F.G.S.
The author dissented from the interpretation of two pit-sections,
one on Aldringham Common, the other near Henham Park Farm,
given by Mr. Searles Wood, in his paper ‘On the structure of the
Red Crag.” Mr. Fisher admitted that the former is at a higher
level than the Thorpe Crag-pit, and the latter than the Wangford
Crag; but he denied that the loam on Aldringham Common is
Chillesford clay, and was doubtful whether even that at Henham
Park Farm belongs to that deposit. Granting, however, that the
loam in the latter case is really Chillesford clay, the author stated
that it is probably carried under the Wangford Crag by a northern
dip. Thus he considered that neither of these sections contains
indisputable evidence of the superposition of the Chillesford clay to
the Fluvio-marine Crag. He also expressed a doubt of the crag at
Bulchamp being a continuation of the Wangford bed, and stated
that it much more resembles the Mya-bed as seen at Yarn Hill. If
this interpretation be correct, Chillesford clay might occur at
Henham Park Farm, intermediate between the Crag of Wangford
and the Mya-bed at Bulchamp.
Gronocican Socrery or Lonpon.—III. Annual General Meeting,
February 15, 1867.—Warington W. Smyth, Esq., M.A., F.RS.,
President, in the Chair.
The Secretary read the Reports of the Council, of the Library
and Museum Committee, and of the Auditors. The continued
prosperity of the Society, and the sustained annual increase in its
numbers, were stated to be especially satisfactory.
The President announced the Award of the Wollaston Gold Medal
to G. Poulett Scrope, Hsq., M.P., F.R.S., F.G.8., etc., in recognition
of the highly important services he has rendered to geology by his
examination and published descriptions of the volcanic phenomena
of Central France, and by his works on the subject of volcanic
action generally throughout the world; and in handing the Medal to
its distinguished recipient, he bore personal testimony to the accuracy
of his descriptions and the soundness of his conclusions; and ob-
served that, however much theoretical views may change with the
advance of our science, he felt assured that Mr. Scrope’s name would
remain linked with the study of this important class of the agencies
which modify the surface of the earth. Mr. Poulett Scrope, on
receiving the Medal, expressed his gratitude to the President and
Council for this recognition of his early labours. The President
then stated that the balance of the proceeds of the Wollaston Dona-
tion-fund had been awarded to W. H. Baily, Hsq., F.L.S., F.G.S., to
assist him in the preparation and publication of an illustrated
Catalogue of British Fossils ; and, in Mr. Baily’s absence, placed it,
together with a diploma to that effect, in the hands of Sir R. I.
VOL. IV,—NO, XXXIII. 9
130 Reports and Proceedings.
Murchison, Bart., K.C.B., ete. Sir Roderick Murchison, in thanking
the Council on behalf of Mr. Baily, remarked upon the conformity
of this particular award to the design of the late Dr. Wollaston in
establishing the Donation-fund.
The President then proceeded to read his Anniversary Address,
in which he discussed some of the most important contributions
to Lithology and Mineralogy during the past few years, prefacing it
with biographical notices of lately deceased Fellows, Foreign Mem-
bers, and Foreign Correspondents, among the most distinguished of
which may be mentioned William Hopkins, Hsq.; the Rev. Dr.
Whewell; P. N. Johnson, Esq. ; G. W. Featherstonhaugh, Esq. ;
James Smith, Hsq., of Jordan Hill; Charles Maclaren, Hsq. ; Parkin
Jeffcock, Esq. ; Prof. H. D. Rogers; Prof. Nils de Nordenskiéld ;
Dr. A. Oppel, Senor Casiano di Prado; Dr. C. T. Gaudin; M.
Deslongchamps.
The Ballot for the Council and Officers was taken, and the fol-
lowing were duly elected for the ensuing year :—President: Wa-
rington W. Smyth, Hsq., M.A., F.R.S. Vice-Presidents : Sir P. de
M. G. Egerton, Bart., M.P., F.R.S.; Sir Charles Lyell, Bart.,
D.C.L., F.R.S.; J. Carrick Moore, Esq., M.A., F.R.S.; Sir R. I.
Murchison, Bart., K.C.B., F.R.S. Secretaries: P. Martin Duncan,
M.B.; John Evans, Esq., F.R.S. Foreign Secretary: R. A. C.
Godwin-Austen, Hsq., F.R.S. Treasurer: Joseph Prestwich, Esq.,
F.R.S. Council: Prof. D. T. Ansted, M.A., F.R.S.; H. W.
Bristow, Esq., F.R.S. ; P. Martin Duncan, M.B.; Sir P. de M. G.
Egerton, Bart., M.P., F.R.S.; Earl of Enniskillen, D.O.L., F.R.S. ;
Robert Etheridge, Esq., F.R.S.E.; John Evans, Esq., F.R.S.,
F.S.A.; David Forbes, Esq., F.R.S.; R. A. C. Godwin-Austen, Esq,,
F.R.S.; J. Gwyn Jeffreys, Esq., F.R.S.; Prof. T. Rupert Jones ;
Sir Charles Lyell, Bart., D.C.L., F.R.S. ; Edward Meryon, M.D. ;
John Carrick Moore, Esq., M.A., F.R.S.; Sir R. I. Murchison,
Bart., K.C.B., F.R.S.; Robert W. Mylne, Esq., F.R.S.; Joseph
Prestwich, Esq., F.R.S.; Prof. A. C. Ramsay, LL.D., F.RS. ;
Warington W. Smyth, Hsq., M.A., F.R.S. ; Captain T. A. B. Spratt,
BR.N., C.B., F.R.S.; Alfred Tylor, Msq., F.R.S.; Rev. Thomas Wilt-
shire, M.A., F.R.A.S.; Henry Woodward, Esq., F.Z.S.
GxoLocicaL Socrrry or Guascow.—The monthly meeting of this
Society was held on the 17th January, in Anderson’s University.—
the Rev. H. W. Crosskey, Vice-President, in the chair.
The following papers were read :—
1. Notes on a Chilognathous Myriapod, and some Fossil Crustacea,
from the Coal-measures of the West of Scotland. By Henry Wood-
ward, Hsq., F.G.S., F.Z.S. of the British Museum. (Communicated
by the Secretary.) The author noticed the discovery by Dr. Dawson,
of Montreal, in 1852, in the Joggins Coal-field, Nova Scotia, of a
Chilognathous Myriapod, Xylobius Sigillarie, found in the interior of
the stump of an erect fossil tree, which also contained the remains
of a reptile, and a land-snail; .and then proceeded to describe a
similar insect, discovered about two years since by the late Mr.
Reports and Proceedings. 131
Thomas Brown, of Stewarton, in the Upper Coal Measures of Kil-
maurs. It occurs in a nodule of ironstone, coiled up somewhat in
the form of the letter J, and is about two inches in length. Each
segment of the body (of which there are upwards of thirty) bears a
slightly raised wart, which indicates the position of the tracheal
openings, while to the sternum of each segment a pair of slender
feet appear to have been articulated. These feet can distinctly be
seen to be composed of several articuli, as in the recent Myriapoda.
No soft-bodied annelide would be preserved in this condition, the
body-rings of worms which the author had examined from Solen-
hofen, for example, being indicated rather by a stain upon the slab
than by any actual relievo evidence of their presence, as shown in
the Kilmaurs specimen. It may therefore be concluded that this
fossil possessed a chitinous exo-skeleton, sufficiently firm and strong
to leave the impress of its numerous and well-marked articuli in the
soft clay in which it was entombed. Mr. Woodward stated that
without further evidence it would be rash to describe this fossil as
specifically distinct from that discovered by Dr. Dawson ; but it was
important to record this instance as the first discovery of Xylobius in
Britain. Preserved with it, in the same nodule, are a perfect pinnule
and several fragments of a Fern, the Pecopteris abbreviata of Brong-
niart. It is extremely interesting to find this presumed terrestrial
Myriapod, both here and also in America, associated with land
vegetation. The evidence of land-conditions to be derived from
associated fossils, must not, however, in this case be too strongly
relied upon, as in the same bed of nodular ironstone are likewise
found King-crabs and other undoubted marine organic remains.
The second portion of the author’s paper (which will be pub-
lished, with accompanying plates, in the next part of the Society’s
Transactions) was devoted to the re-description (1) of Belinurus
trilobitoides and Prestwichia rotundata, two species of Limuloid Crus-
tacea, also found in the nodular ironstone of Kilmaurs, from examples
of which he had been enabled to detect several important structural
characters not previously noticed ; and (2) Pygocephalus Cooper,
Huxley, from the same locality. In conclusion, he stated, having
frequently observed, in the examination of various genera and species
of fossil crustacea, that certain species in dying always appear to
have assumed a particular position. Certain others, after death,
appear always to break up in a systematic manner. Ceratiocaris 1s
generally found in the Upper Silurian of Lesmahagow, with its
tail in its mouth. Trimerocephalus, in the Devonian of Newton,
always has its head directed towards its tail, and detached. Again,
one species of Crustacea always occurs with the dorsal aspect
exposed upon the matrix ; another as invariably presents the ventral.
Thus the specimens of Pygocephalus present the ventral aspect ex-
posed to view, whilst the dorsal adheres as firmly as possible to the
matrix. .
2. On the Sections of Igneous Rocks on the Rye, Ayrshire. By
Mr. R. Whyte Skipsey.—Mr. Skipsey described the three principal
sections which are observed in descending the bed of the stream,
182 Correspondence.
between the Howrat Toll-bar and the lofty escarpment of Carbon-
iferous limestone a short distance above the town of Dalry.
3. Notes on some Sections in the Old Red Sandstone and Ballagan
Series in Dumbuck Glen. By Mr. John Young.—Mr. Young stated
that the sections exposed in Dumbuck Glen belong to the Old Red
Sandstone, and to a series of thin-bedded limestone strata, locally
known as the Ballagan beds, from being typically developed at the
Spout of Ballagan, near Strathblane. The latter are by some
geologists considered to be of Carboniferous age, and by others as
belonging to the Old Red Sandstone. ‘The only evidences of organic
remains yet found in them are fragmentary fish scales, plants, and
annelide impressions.— Glasgow Herald, 19th January, 1867.
Lirzrary anp PuinosopHican Socimty, Mancumster. January
8th, 1867. Edward Schunck, Ph.D., F.R.S., etc., President, in the
Chair. Mr. Binney, F.R.S., F.G.8., exhibited two remarkable
fossils, discovered by Mr. Joseph Tindall, of Thomas-street, Hud-
dersfield, in the Lower Coal Measures near that town. One was an
insect, and, according to Mr. Tindall, belonged to Dr. Dawson’s
genus Xylobius and probably to his species Sigi//arce. It was found
in an old deep mine at Cooper Bridge, and is the first instance of a
specimen of that genus having been met with in England.t The
other bore some resemblance to the pupa-state of a Coleopterous
insect, not much unlike the pupa of a nut-weevil or some such
insect. It was found in the Cinderfield Dyke Pit, at Bradley, near
Huddersfield. These specimens give us evidence of the former
existence of insect life during the Carboniferous epoch which a few
years since we should scarcely have expected; but after the dis-
covery of a fossil spider in the German Coal-measures, scarcely to be
distinguished from a recent genus, we must expect great additions to
be made to the Carboniferous fauna, as doubtless the rich and
luxuriant vegetation of that remote period would afford food and
shelter for numerous insects.—Proceedings—Lit. and Phil. Society.
—Vol. vii—No. 8—Session 1866-7.
CORRESPONDENCE.
THE LATE MR. F. J. FOOT.
To the Editor of the GmotocicaAL MAGAZINE.
Srr,—Will you allow me to correct some inaccuracies in your
obituary notice of my late lamented colleague, Mr. F. J. Foot.
The date of his appointment to the Survey was August Ist, 1854,
not 1856.
Sir Henry Dela Beche died on April 11th, 1855, but continued his
annual visits to Ireland to the last, and I well recollect his expres-
1 A specimen of Xylobius, discovered two years ago, at Kilmaurs, near Glasgow,
by the late Mr. Thomas Brown, was described by Mr. Henry Woodward, before the
Glasgow Geological Society, on the 17th January, 1867.—See Report of that Society,
at p. 130 of the present Number—Enir.
Correspondence. 133
sions to myself of satisfaction at Mr. Foot’s style of work, in the
autumn of 1854, when we were all together in the neighbourhood of
Bantry Bay.
There is no mention in your notice of Mr. Foot’s paper “On the
Distribution of Plants in Burren, Co. Clare.” This paper is pub-
lished in Vol. xxiv. of the Trans. R. I. Academy, and is accompanied
by a map, which shows at once the precise localities where several
rare and interesting plants occur, and the relation between their
geographical distribution and the geological structure of the district.
When mentioning Mr. Foot’s share in the production of thirteen
of our small memoirs called Explanations, it should have been
added that his name also appears as sole or joint surveyor on thirty
sheets of our published maps, and seven sheets of sections.
I am happy also to say that the reading of his paper, containing
his botanical and geological observations on a part of Norway, will
not be interrupted by his death. The paper, with its illustrations
complete, is now in my hands, and it will have been read at a
meeting of the Royal Dublin Society before this letter can be
published in your next number.—I am, Sir, your obt. servant,
J. Burrs JUEES.
GronocicaL SuRvEY oF IRELAND,
51, StePHEN’s Green, Dusin,
4th February, 1867.
Note.—We are requested by Mr. J. Brete Juxes to make the following corrections
to his last letter which appeared in the February Number of this Magazine, p. 87.
At line 10 from bottom of page 87, for ‘‘ break in the veins,” read “ break in the
series ;”” at page 88, line 4 from top, insert a full stop after “‘ Pilton beds, ete. ; delete
full stop in line 5 from top, and substitute comma.—Eprr.
ON DENUDATION AND THE FORM OF THE GROUND.
To the Editor of the GnoLocicaL MaGazine.
Dear Srr,—Had my friend, Mr. Kinahan, bestowed equal atten-
tion upon the passages immediately following that which he quotes
from your January number, or its plates, he might, perhaps, have
gathered therefrom that I had not forgotten such instances as the
coast islands of Cork and Kerry. The inference would have been
more evident than that, because these islets are now acted upon by
the sea, isolated pillars of rock must have been formed by marine
denudation. Inverting the case he puts, and supposing any rain-
worn pinnacle depressed to form an island, it follows that this
situation might sometimes prove but little or nothing with regard to
the formation of “isolated rocky pillars” by subaerial or marine
denudation.
Leaving aside elevation and depression, as remotely connected
with the cases in point, some of the island rocks named.are of so
great a height (about 600 ft.), that the sea can only reach their most
denuded portions in the form of rain-like spray, and it will be
admitted that rain does sometimes occur on that coast.
I have heard, indeed, that a water-butt was washed by storm
breakers from a considerable height (about 350 ft), near a lighthouse
134 Correspondence.
on the Great Skellig, yet could not rely upon an uncorroborated
report as proof of the vertical distance at which the sea can occa-
sionally act upon the weather side of a lofty rock. Its agency in
forming some isolated pinnacles has not been denied.
Truly yours, 0187 + 5°.05 Not given. 86
31957 °0151—
52894 0131 +
73831 0316 + —1°.01 5°1 14°8
94768 0452 + —7T.17 —3°2 21°0
ie 115705 *0460— —T7°.52 —3° 21°3
The fifth and sixth columns of Sir Charles Lyell’s table, which give
the mean hottest and coldest months in the latitude of London when
winter is in aphelion, are calculated from the present means. It seems
to me, however, that, for cold epochs, it will be safer to calculate from
the mean as it would have been had the Gulf Stream not existed,
1 Geol. Jour., Vol. viil. p. 68. 2 Phil. Mag. for Feb., 1867, p. 3.
Fisher—Ages of the “Trail” and “ Warp.” 197
and accordingly I have adopted Mr. Hopkins’ value of 23° F. for
: 239° + ¢° 0:9832\ 2
Snowdon. The equation then becomes ue = ( ee)
I have also added Mr. Croll’s values, on the supposition of the Gulf
Stream being only partially deflected.!
My fifth column is calculated from the equation—
Excess of winter over summer — mentnk x year
= 31416 * Year.
This is slightly more accurate than the rule I gave in the “‘ Reader,”
4th November, 1865.
Referring to the table it will be seen that in the year 1800 the
eccentricity was ‘0168. Hence, on the first preceding occasion of
winter occurring in aphelion, the eccentricity was greater than at
present by a small amount. On the two next occasions it was less.
On the fourth it was considerably greater, and winter fifteen days
longer than the summer. On the fifth this difference had increased ;
and on the sixth occasion it was larger still; but it was diminishing
rapidly.
Now it is remarkable that though Sir Charles Lyell notices the
high eccentricity occurring about the time of these last two epochs,
between which falls his period 4; yet he has not attributed any
known Glacial phenomenon to it. Both he and Mr. Croll consider
it too recent for the so-called Glacial epoch, and Sir Charles thinks
it not recent enough for the Reindeer period. I would suggest that
it is extremely probable that this was the epoch of the formation of
the trail, and of the last general denudation of our country. —
Then the period 11020 years before 1800 may be supposed to have
been that of the reindeer. For the eccentricity was at that time
appreciably larger than it is at present, amd the winter nine days
longer than the summer. This, with the winter in aphelion, might
well have produced the change of climate necessary for the south-
ward migration of the reindeer, though not sufficient to envelope
these latitudes in a sheet of ice. The objection, that the summers
would then have been too hot for the reindeer, may perhaps be met
by observing, that the Southern range of that animal in Northern
Asia at present reaches almost to latitude 50°, which is within the
limit of the summer isotherm of 68°; while, on the other hand, the
localities, in which its remains have been found in Southern Europe,
must have been within the influence of the Atlantic, whose waters
were at that time cooler than at present. Hence we may suppose
that those countries would not have been heated, even by a nearer
summer’s sun, more intensely than the plains of Asia, which the
reindeer inhabits, are heated at the present time. Still further, we
must not forget Mr. Croll’s arguments for cold and cheerless summers
under a high condition of eccentricity. I am inclined to think that
this was also the period of the formation of the warp, when, as I have
shown, the winter frosts were more severe than they are at present.?
The submergence of our lower valleys, beneath the Scrobicularia mud,
1 Phil, Mag, Feb. 1867, p. 3. 2 Geol, Journal, vol. xxii.-p. 564.
198 Fisher—Ages of the “ Trail” and “Warp.”
was one of its later phenomena, and the retirement of the sea, which
deposited it, formed the commencement of the recent period."
It is very satisfactory to observe that the periods thus assigned to
the two Glacial phenomena, which I have been discussing, c cause
them to fall into the positions which they ought to occupy on purely
geological grounds, and agree with awards of Sir Charles Lyell
and Mr. Prestwich. From reasons, solely grounded upon the order
of superposition, I concluded my paper on the warp with the following
summary :—
“Upon reviewing the changes which have been indicated by the
phenomena discussed in the present paper, we have disclosed, in the
first instance, a condition of the surface when the general features of
the landscape were the same as at present, during which the great
mammalian fauna flourished contemporaneously with the fabricators
of the chipped flints” (the Paleolithic period).
“We have, subsequently, though perhaps not in immediate sequence,
a period of extensive denudation, indicated by the furrows filled with
materials from the higher aucune, which have travelled in a plastic
state, and which I have called ‘trail.’ This denudation brought the
surface almost exactly to its present form. The period of the for-
mation of the warp succeeded, in which the winter frosts seem to
have been more severe than at the present time.
“It was either during this period or shortly afterwards, that the
submarine forests flourished. A submergence of moderate amount,
measured by a few tens of feet, next followed, and the Scrobicularia
mud was deposited over the lowest forest-grounds. The sea was
then depressed again, and the recent period commenced.
“The changes of form in the present surface which have taken
place since that time may, I believe, be easily recognised, since they
usually interrupt the more general contour of the surface.”’?
Upon correlating these geological conclusions, with what may be
called our astronomical ones, we find that the Paleolithic period,
shown to be older than the “trail,” is thrown into the times ante-
cedent to Sir Charles Lyell’s period a; where, also, he himself
places it. Nevertheless, if I should venture to differ from so great an
authority, I would suggest that the period B, to which he inclines to
assign it, might be somewhat too early, the eccentricity being likely
to have rendered it too cold for the phenomena observed, and that.
the climate of some part of the interval between 100,000 and 200,000
before a.p. 1800, would have been more in accordance with what
was requisite, and probably of sufficient duration.
There followed after the Glacial era of the “trail,” a lengthened
period of equable seasons of about 80,060 years, which would have
been that of the submarine forests and their occupants. Elephas primi-
genius was still living in this Island,—witness his remains found at
Holyhead harbour, preserved in the British Museum.
A short period of severe winter cold succeeded, which was the
period of the warp, and of the Scrobicularia clays; and the date of
it agrees remarkably with the result arrived at by Mr. Prestwich, on
Geol, Journal, vol. xxii. p. 564. 2 [bid.
G.Massee del®et jith M&N Hanhart mp
CYCADEAN STEM FROM LEIGHTON BUZZARD.
Carruthers—On a Fossil Cycadean Stem. 199
summing up the evidence in regard to the Quaternary gravels. He
is of opinion that the large pachyderms lived down to the commence-
ment of the alluvial period, and on that supposition says, “I do not
see any geological reasons why the great extinct mammalia should
not have lived down to comparatively recent times, possibly not
farther back than 8,000 or 10,000 years ago.’ In other words, he
puts that period as having elapsed since, as I understand him, the
last submergence of our lower valleys took place.
According to my views this submergence would have passed away
in about a quarter of the term of 10468 years, subsequent to the
epoch 11020—that is, about 8,000 years ago. ‘This is, to say the
least of it, a remarkable coincidence.
IIl.—On Crcapvorpra Yaresi, A Fossin CycapEaAN STEM FROM THE
Potron Sanps, BEDFORDSHIRE.
(PLATE 1X.)
By Wm. Carrutuers, F.L.S., of the British Museum.
A aes examining the collections of the Geological Society at the
time of preparing the notes I published some months ago, on
the Fossil Cones of the Secondary Strata, I found a small fragment of
a curious vegetable organism, the nature of which I was then unable
to determine, but which I was allowed by the kindness of the
Secretary to take with me for the purpose of further examination.
Some months ago I obtained from James Yates, Esq., a more perfect
specimen, which clearly showed that it was the portion of the stem
of a cycadean plant, as Mr. Yates had already determined. Professor
Church subsequently brought me a yet finer specimen from the
Museum of the Royal Agricultural College at Cirencester, and I have
a fourth fragment from the collection of Professor Morris.
All the specimens were found in the iron and green sands of
Potton, which rest on the Kimmeridge and Oxford clays, and are
covered by the Gault. Mr. Seeley, who has paid some attention to
these beds, kindly informs me that he considers them to “ represent
in their upper part the Lower Greensand, which part is generally un-
fossiliferous ; the middle part is very rich in fossils, including many
vegetable remains, such as fir and other cones, wood, etc. These beds
are regarded as a marine representative of the Purbeck and Wealden
period ; and at the bottom are the representatives of the Farringdon
gravels, and unfossiliferous sands.” The Cycadean stems are found in
the middle part of the sands. They are converted into a rich brown
hematite, containing a larger proportion of iron than bog iron ore.
Mr. Pettit drew the attention of the Geological Society to these
stems at its meeting on December 2nd, 1857, when he laid some
fine specimens on the table. He referred them to Clathraria ; but no
description of them was published, nor further notice taken of them.
Professor Morris had had his attention directed to this fossil some
years ago, and having seen the fine specimen at Cirencester, he came
to the same conclusion as Mr. Yates regarding its affinities. |
It must be referred to Buckland’s genus Cycadoidea = Mantellia,
200 Carruthers—On a Fossil Cycadean Stem.
Brongn. Besides the two species described by Buckland, from the
isle of Portland, the genus contains a third species from the Lias of
Lyme Regis, also having, like the original species, a bulbiform trunk,
and three species with cylindrical stems from Secondary strata in
France. All the species are characterised by having their trunks
covered with the persistent bases of the petioles. With Professor
Morris’s concurrence I have named the species -Cycadoidea Yatesit,
after a gentleman whose name is well known, among other things, as
a successful cultivator and diligent student of the interesting Order
of plants to which the fossil belongs. JI do not hesitate to give it a
specific name, as the materials are more than sufficient to show its
affinities ; and though other vegetable fossils are known from the bed,
none have been described to which this could belong.
The species may be thus distinguished :—
Trunk cylindrical, covered with the persistent bases of the petioles,
which are rhomboidal in form, and terminate in a tumid boss, the
apex of which is directed upwards.
The fossil belonged to an arborescent Cycad resembling in aspect
the tall cylindrical stems of Cycas or Macrozamia, and differed in this
respect from the spherical or ovoid trunks belonging to the genus,
which were described by Buckland and Lindley. The cellular axis
was relatively very large. The pith has disappeared, except in one of
the specimens, where there are still some indications of it, and of the
vascular bundles which abounded in it. The woody cylinder surround-
ing the pith consists of two rings, everywhere pierced by medullary
rays, which are often so large as to separate the rings into numerous
series of woody wedges, as in recent Cycadee. 'The presence of discs
on the woody vessels has been detected both by Professor Morris and
myself. The inner surface of the woody cylinder is marked by
numerous narrow grooves and perforations, formed by the vascular
‘bundles, as they passed from the pith into the wood. ‘The outer sur-
face has similar scars, produced by the vascular bundles, which passed
from the wood to the leaves ; but they are here larger and more regu-
larly disposed than on the inner surface. Between the wood and the
bases of the petioles there interposed a very thin layer of cellular tis-
sue, through which the vascular bundles passed in an upward direction
towards the petioles. In recent Cycadee, as well as in the other fossil
British species of this genus, this layer is very much thicker than in
our species. The bases of the petioles rise from this cellular layer.
The leaves of Cycadee perish at first like the fronds of ferns and the
leaves of monocotyledonous plants, which not being articulated to
the stem of the supporting plant, wither and decay upon it. Buta
true articulation exists in Cycads, not as in deciduous leaves at the
point where the base of the petiole rests on the surface of the stem,
but at some distance from that point. When the decayed leaf at
length falls off, the cicatrix is covered by an epidermal layer, giving
to the persistent bases of the petioles an appearance not easily dis-
tinguished from the scales, which are interspersed among them.
Some species of the South African genus Encephalartos afford fine
‘Specimens of this structure, the outer surface of the trunk having
Salter—On the May Mill Sandstone. 201
sometimes, as in E. Altensteiit, a quarter of its diameter composed
of the persistent bases of the petioles. This also is a character as
we have seen of the genus Cycadoidea, and our species may be dis-
tinguished from the others by the regular arrangement and symmetri-
cal form of the bases of the petioles. They are rhomboids, the horizontal
diameter of which is but little more than the perpendicular, and differ-
ing in this respect not only from all the other described recent species,
but also from all the living Cycads with which I am acquainted.
EXPLANATION OF PLATE IX.
Cycadoidea Yatesii, Mor. and Car. From the specimen belonging to the Museum of
the Royal Agricultural College at Cirencester. Two thirds the natural size.
Fig. 1. a. The persistent bases of the petioles. 0 and c. The lower portion of the
stem, deprived of its outer covering, and showing at ¢ the thin external
layer of cellular tissue, and at d the outer surface of the woody cylinder.
Fig. 2. The upper surface of the same stem. a. The internal cavity occupied by the
pith, but in the specimen figured containing amorphous iron-ore. 6. The
inner woody ring. ¢. The outer woody ring. 4. The bases of the
petioles.
IJ.—On toe May Hitt Sanpstone.
By J. W. Satter, A.L.S., F.G.S.
T is at all times difficult to fix the parentage of a new geological
idea. So many circumstances and so many hints and observations
converge to its establishment, when the due time comes for its appre-
ciation, that, looking back, it seems hardly possible to disentangle
the ideas of one workman in science from the suggestions of another.
Hence it is always difficult to establish an exact priority of claim in
questions which have remained long unsettled.
In the elaborate, but too short volume by Prof. Ramsay and my-
self, on the Geology of North Wales (Mem. Geol. Surv. vol. iii.
1866), an attempt is made by the former to give a succinct history
of the order of discovery of the various members of the British
Silurian (and Cambrian) groups. With respect to the May Hill
Sandstone—a group most important, as all will now recognize, as
the key to the structure of Wales and the bordering Silurian coun-
ties,—I will add a few facts which suggest themselves to me on
reading Prof. Ramsay’s brief and important chapter on the nomen-
clature (chap. i.).
Even before the publication of Prof. Phillips’ memoir on the
Malvern Hills, 1848, it was observed by the Professor, then paleon-
tologist to the Survey, that the Caradoc and May Hill Sandstone of
the Silurian System included an upper group, distinguished by
the prevalence of Upper Silurian fossils ; and this upper rock of the
Malverns was distinguished by the term, ‘“‘Upper Caradoc,”—a bad
name, since Sir R. I. Murchison had already called it May Hill Sand-
stone. It was known in 1848, by the Survey, that this Upper Cara-
doc ranged unconformably round the great Cambrian and Lower
Silurian Island (so to speak) of the Longmynd, resting at one place
on Llandeilo rocks, at another on the still older slates of the Long-
202 Salter—On the May Mill Sandstone.
mynd itself. And in Prof. Ramsay’s short account of the Geology
of North Wales (vol. iv. Geol. Journ.)—to which, by-the-by, he
makes but little allusion in the volume lately published—the rela-
tions of this Upper Caradoc were discussed by himself and Mr.
Aveline; its unconformity recognized; and its relative age (by the
fossils) given by Prof. Forbes and myself. But, by an accident, one
or two typical Lower Caradoc fossils were again wrongly quoted
from it, as had previously been done by Prof. Phillips.
It was, moreover, known that these ‘“‘ Pentamerus beds, or Penta-
merus and Hollies Limestone” of the Silurian system (1839), were
equivalent in age to the “Clinton group” of America, which Prof.
Hall, in his Geology of New York (1843), had distinctly stated
appeared to lie on the eroded surfaces of the underlying rocks, and
yet to contain a few, and only a few (Bellerophon bilobatus being the
chief) of their fossils.
We ought not, therefore, to have been surprised to learn (when in
1853 Prof. Sedgwick and Prof. M‘Coy read a paper before the Geo-
logical Society on the distinctness of the two rocks, ‘ May Hill” and
Caradoc”), that there must be a total difference in their aze—only
to be expressed by the use of separate terms—the one being of the
age of the Bala rocks (Upper Cambrian of Sedgwick); the other a
Wenlock grit or sandstone. These are the Professors’ own words.
But this view of their total distinctness was not reconcileable with
the fact, that the author of the “Silurian System’’ had obtained a
mixed series from the typical locality where both were seen, viz., the
Hollies Iimestone, near Acton Scott. It was resolved by the then
Director of the Survey, Sir H. de la Beche, that a survey should be
again made along the Wenlock valley (Apedale), and the veteran
geologist, Mr. Talbot Aveline, and myself, then assistant to Prof. Hd-
ward Forbes, were appointed to this duty. I wrote to Prof. Sedgwick,
telling him our object ; and his reply was, we should find them dis-
tinct and unconformable ; he had the previous year tried to ascertain
it. It was a cold spring in April, 1853, and not very pleasant
weather for tracing muddy brook sections in clay land; but we had
thick boots and light hearts, and the primroses and early violets
were in full bloom. We found the unconformity first in the most
difficult of all the sections, viz., the Onny river at Cheney Longville.
And the slight discordancy (only a few degrees of angle) was only
discoverable by wading knee-deep along the shelves, and one at a
time hammering, while the other observed the line of contact from
the opposite bank. Prof. Ramsay joined us here, and confirmed
the unconformity by the same amphibious process. We need hardly
have given ourselves so much trouble; for by proceeding north-
ward we found the Pentamerus beds and purple (Tarannon) shale,
thickening and thinning out, and forming “Jacob-stones.” Hvery
cottage doorsill and well step was Pentamerus limestone, when we
hit upon the right line, which was-no little trouble to do.
Moreover, Mr. Aveline, being an old stager, had bethought him
that we must first gain a true section of the under rocks. This he did
readily by going from Horderly turnpike to Cheney Longville and
Salter—On the May Hill Sandstone. 203
Stretford Bridge; then by tracing the Caradoc divisions northward
—some five or six very distinct ones—we found that they were suc-
cessively each and all overlapped and covered up by the Pentamerus
limestone and grit, all the way up to the Wrekin, where, indeed,
they lie on the very lowest beds, or Shineton shales and slates, which
I take leave to call the top of the Llandeilo Flags proper, and believe
this to be their true position.
However, the unconformity was fully proved ; and a pleasant bit
of geology it proved when the snow was gone from all but the
Longmynd top. I shall not easily forget the hot day we finished at
the Wrekin. Professor Ramsay and Mr. Aveline had been up before ;
but nothing would do but I should drink at the Raven’s Cup; and Jf
shall remember that, for it had been artificially filled that day, and
not with pure water.
On going to the Hollies Farm, in a pelting snow shower, I found
the source of all theerror. The house is built on true Caradoc flags,
so caleareous and so full of Caradoc or Bala fossils, that they might be
burnt for lime ; and a little further down the brook, the Pentamerus
limestone crosses, thick enough to tempt them to use it for the kiln.
But the walls of the now deserted kiln were built of the Caradoc
flags from the house quarry, while the May Hill or Pentamerus
limestone had been burnt. The fire had calcined both, and frag-
ments of each, found in the kiln, had been most innocently and unsus-
pectingly gathered by the Silurian chief, and figured together by
accurate James Sowerby! Who was to blame? Not Sowerby, for
he rightly named the fossils from the “‘ Hollies.” Scarcely Murchi-
son, for who could dream that two limestones of such different age
were calcined in the same kiln by accident? Not the farmer, who
was wise enough to build his kiln of the firmer and less valuable
stone. It was a chapter of accidents, such as has often happened
before and will again. But there was no longer any doubt as to the
supposed admixture, and the experimentum crucis had been made in an
old lime kiln.
Henceforward all was plain sailing. The Upper Caradoc was
abolished, for the May Hill Sandstone had acquired its right meaning ;
and as fossils were abundant in it, we easily rearranged the drawers
of the Museum in accordance with the new facts. But this was not
all. Professor Sedgwick and myself had shewn in 1845 (Quart.
Geol. Journ.), as the result of our summer’s work in North Wales in
1843, that the fossils of the uppermost portion of the Bala (or
Caradoc) rocks in Montgomeryshire were full of these same Penta-
meri and of other fossils, Petraig, Atrypa reticularis, etc. These in
many places were found (and more have been found since) to range
along the border of the Upper Silurian rocks. In South Wales Sir
Roderick had described them from near Llandovery, from Haverford-
west, from Marloes Bay ; and they were included in what was then,
indeed, a heterogeneous assemblage, under the term of Llandeilo
Flag. I examined the country, from Builth to Carmarthen, in
1846, made easy then by the accurate map; and recognised, of
course, the Upper Caradoc, as we then had begun to call it. It was
204 Salter—On the May Hill Sandstone.
evident enough, after 1853, that these localities must be revisited ;
and the last official act that I remember of Sir H. de la Beche was a
kindly “God-speed” to Mr. Aveline and myself. We set out in 1857
for a fresh boundary line from Builth to Marloes Bay. But this
journey (the results of which Sir Henry did not live to see) gave us
a much more difficult task. Instead of soft shale, limestone, and
sandstone, we had to draw a boundary between hard cleaved slate,
and hard cleaved gritty slate; and the solemn pipe often assisted
our deliberations. We traced the whole boundary together ; found
there were two Pentamerus series—one upper, with Wenlock fossils
and Pentameri, lying unconformably upon a lower, full of Caradoc
fossils and Pentameri—just such a mixture as had been at first
supposed in Shropshire, but had turned out untrue. Here it was true
enough ; and many a long day was spent in deciding which was the
upper and which the lower. For when two slates, one only a little
more gritty than the other—tilted together, and bent and broken
together, and cleaved in the same direction—have to be distinguished
in a cultivated country, all I can say is that, if any one thinks
geology is easy work, let him try that sort of thing.
However, in course of time it came all right. There was a May
Hill rock, which began at Builth and swept on, in thick or thin
patches, as far as Llandeilo, lost there, and again coming out to sea in
the fullest force at Marloes Bay and Wooltack Park. Cleaved and
tilted as they were, there could be no doubt of them. Professor
Ramsay joined us at Marloes Bay, and accompanied us back to
Haverfordwest.
And under these Lower Pentamerus beds at Haverfordwest, and
on the rolling hill tops north of the Towy, and thence to Llando-
very, we sought to find the boundary between these Lower Llando-
very rocks (as Sir R. Murchison calls them) and the true Caradoc
beneath. To me they seemed conformable; but Mr. Aveline after-
wards by himself did find, in tracing them painfully in detail, and
following them northward and westward, that the lower beds were
sometimes a little discordant on the Caradoc. I believe no one but
himself could have proved it. But it must be true, or there is little
faith in fossil evidence, for the change in the fauna is sudden and
considerable. ;
This account, rather briefly and imperfectly given, is all that 1
remember of the history of the May Hill and Llandovery rocks ; but
it may, perhaps, be enough to show how the observations of many
men and many minds must concur, before the hypothesis is reached—
which, as our old chief, Sir Henry, used to say, is the “ peg to hang the
facts upon.” Sir R. Murchison had traced the course of the ‘ Penta-
merus beds” around the Longmynd and Shelve country without
dreaming they were other than part of the true Caradoc. The Survey,
misled by the supposed admixture of types, could get no further than
an Upper and Lower Caradoc. Hall had noticed, but failed to see the
full significance of the unconformity in New York. Pouring rain
had beaten Sedgwick and M‘Coy in their gallant attempt to take the
Wenlock Valley by storm in 1852. And neither Swedish nor Russian
~ Greenwood—On Valley Terraces. 205
geologists appear to lave observed the discordancy of their great
Pentamerus zone. ‘The fruitful idea in this case was conceived by a
good paleontologist, before he had even seen the rocks in question!
And it was followed up by a man of genius, who had learned the
importance of the fossil data to be second, and not first, in geological
study. Coming fresh from Wales, where the Silurian rocks are alto-
gether unconformable on what he termed Upper Cambrian or Bala
rocks, he was ready to make the most of the suggestion of his friend,
and was the cause of proof being made by his pupils in the science.
TV.—VALuLEY TERRACES.
By CotoneL GrorcE GREENWOOD.
(PLATE X.)
N the Journal of the Geological Society for November, 1866, page
463, Mr. Tylor gives a paper on “The interval of time which
has passed between the formation of the upper and lower valley
gravels.” He says, ‘Mr. Prestwich argues that, although the upper
valley gravels are at a higher relative level than the lower, yet the
higher series are always the older, and the lower the more modern ;
and we have thus the ordinary superposition of new over old strata
supposed to be reversed. This difficulty is considered by most geo-
logists to-have been surmounted by Mr. Prestwich’s arguments, and
his classification of the gravels has been generally accepted. My
own opinion is that the evidence on which Mr. Prestwich’s theory is
based is insufficient.” If the gravel terraces were on one another
as well as above one another, there would not only be a difficulty, but
an wnpossibility to surmount. But the terraces are not on one another
—that is, although they are in level above one another, they are not
vertically above one another. If in making a railroad cutting the
sides were terraced, the upper terraces would be the first formed,
and would consequently be “the older.” The lower terraces would
be the last formed, and would consequently be “the more modern.”
Mr. Tylor himself will allow that the upper part of a railroad cut-
ting must be excavated before the lower part of it; and that if de-
posits were made during the excavation, the upper deposits would
be the first made or “the older ;” the lower deposits would be the
last made or “the more modern.” The case is the same if, instead
of the formation of a railroad cutting by navvies, we suppose the
formation of a valley, and the excavators to be rain and rivers, Mr.
Tylor feels himself aggrieved that the valley of the Somme has “a
transverse section of five hundred times the area of the present
water-channel.” It might have the same area without any “ water-
channel ”—that is, without any river at all, simply from the erosion of
rain. Indeed, it is only when rivers are flooded by rain that they erode
the non-alluvial parts of their channels and deposit on the alluvial parts.
So in chalk and other porous districts where the downward soakage of
rain is not stopped, and consequently, where no springs are forced out
to make streams, enormous valleys are formed by the erosion of rain
only. Such may be seen in Salisbury plain. I have said, in “Rain and
206 Greenwood—On Valley Terraces.
Rivers” (page 152), of the valley of the Ganges: “In the rainy season
there is, perhaps, a body of surface water which flows down the vale
to the sea in volume fifteen times as great as the spring water; and
were every spring of the Ganges permanently dried up, the vale
would still be flooded every year by a stream in volume only less by
one fifteenth part than that which flows every rainy season now, and
fourteen times greater than that which flows in the three dry months.”
And what makes the river flood in the rainy season except the rain?
“ Quum fera dilivies quietos irritat amnes.”
And what is even the spring water of rivers but rain reappearing and
returning to the sea? Also (op. cit., page 155), “The source of the
valley (that is the rain source of the valley) is always much higher up
than the source of the river (i.e., than the spring source of the river).
The river has no power of making a valley above it, but a torrent of
rain water has the power of scooping a valley below it. Terraces of
gravel on the sides of chalk valleys are in general remains of beds of
rivers. The rivers having eroded the softer chalk sides of their
beds, deepen their valleys, and leave their beds as terraces on the
hill sides. So that any number of long lines of gravel terraces,
which were the beds of rivers or even the beds of rain valleys, may
be deposited on the sides of valleys,—first on one side of the valley,
then on the opposite side. Such terraces are, usually, on one side
of the valley only. Parallel terraces, one on each side of the valley,
may be ancient shores. But the vast majority of them are the
remains of alluviums where no lakes have ever been. The alluviums
are formed by the stoppage of the lowering of the valley. The
valley above the stoppage is then worn horizontal. ‘The rain flood
waters from the sides and inclined parts of the valley, checked at the
flat plains, overflow and deposit alluviums on these flats. The sea
stops the lowering of every valley, therefore the bed of every valley
is flat and alluvial at the end next the sea. But besides this marine
or main alluvial plain, a valley may have any number of what I have
called patches of alluvial plain at any distance from the sea. These
patches, as I have had the honour to say in the Guoznocrcan Maca-
ZINE,! occur above every hard stratum which crosses the course of
the valley or river, and which stops for a time the lowering of the
valley or river bed. Rain and the river then form a horizontal flat
on the comparatively soft strata above the gorge, and an alluvium on
the flat. When the gorge is deepened and widened, the alluvium
above is cut through, and disappears, leaving only two parallel terraces,
and a new flat and a new alluvium are begun at a lower level. Lord
Milton gives a drawing of the parallel terraces on the Fraser river
which illustrates this theory (see Plate X.).? The terrace next the
river is now in actual formation from the annual overflow of the
river and the run of the sides of the valley and the old terraces.
1 Gro. Mac., Vol. III. p. 519.
2 The accompanying engraving has been most obligingly lent for the illustration of
Colonel Greenwood’s paper by Viscount Milton and Dr. W. B. Cheadle. It is one
of the numerous illustrations to their interesting work, entitled, ‘The North-West
Passage by Land. Being a narrative of an Ixpedition from the Atlantic to the
Pacific.” 8vo, London, 1865. Published by Messrs. Cassell, Petter, and Galpin.
(90% abvd aagy) ‘UIALY UISVU,T AHL NO SGOVAUaT, THT,
ike
HAO
MN
|
|
OS Td NI ZO “LOST “OVI “Tory
—
Greenwood—On Valley Terraces, 207
The terrace next above is the last formed, and the topmost terrace is
the first formed. The conical mountains, on which the remains of
the terraces rest, exist only because they are harder than the beds
which have formerly surrounded them; and, as I have said of the
Weald Hill and the North and South Downs—those all-powerful ex-
cavators, air and moisture, rain and rivers, have as much formed
these cones as the sculptor has formed the statue out of the Parian
or Carrara block. And the human and the natural operators have
worked on the same principle—that is, by the abstraction of external
parts. And these cones stand out a magnificent monument of the
enormous masses which have vanished by the disintegration of the
atmosphere and the erosion of rain and rivers. ‘These cones, how-
ever, though the monuments are by no means the measure of this de-
nudation, since they have themselves been melting away for “an
eternity of time,” and are day by day vanishing tenues in auras at
this instant. All this is going on now all over the world, and all day
long. These simple yet sublime truths are beneath the contempt
of poor marvel-secking human nature. We must have a cata-
clysm, or a glacial epoch, or a “gravel period,” to account for
every heap of rain-wash. In his description of the parallel ter-
races of the Himalaya, Dr. Hooker’s facts exactly correspond with
my theory, that from the alternation of hard and soft strata across
valleys, an alternation of gorge and alluvial flat results: as each
gorge sinks and widens, the alluvium above is cut into two
parallel terraces. While on the Tambur river (page 199, vol. i.’),
Dr. Hooker says: “‘I was almost startled with the sudden change
from a gloomy gorge to an open flat.” Page 191, hesays: ‘“ Above
these gorges are enormous accumulations of rocks, especially at the
confluence of lateral valleys, where they rest upon little flats like the
river terraces of the Mywa.” Now these “lateral valleys” (longi-
tudinal as regards the stretch of the strata) are simply the consequence
of the erosion of rain and rivers in the soft strata above or behind
the hard gorges, as I first said of the lateral valleys in the Weald
clay above or behind the gorges of the North and South Downs. In
his description of the terraces of the Yangma valley (page 219,
vol. i. ibid.), Dr. Hooker begins with a gorge: ‘‘The scenery was wild
and very grand, our route lying through a narrow gorge choked with
pine trees, down which the river roared in a furious torrent.” ‘The
path was very bad ; often up ladders and along planks lashed to the
faces of precipices, and overhanging the torrent which it crossed
several times by plank bridges.” Above this gorge, and above other
“ contracted parts of the valley,” come his supposed ancient lake beds
and the parallel terraces which he depicts, and of which he says
(page 233): ‘On the opposite flank of the valley were several ter-
races, of which the highest appeared to tally with the level I occupied,
and the lowest was raised very little above the river ; none were con-
tinuous for any distance, but the upper one in particular could be
1 Himalayan Journals. Notes of a Naturalist in Bengal. The Sikkim and Nepal
Himalayas. By Joseph Dalton Hooker, M.D.R.N., F.R.S., London, 1855. Pub-
lished by John Murray.
208 Greenwood—On Valley Terraces.
most conspicuously traced up and down the main valley, whilst
on looking across the eastern valley a much higher but less dis-
tinctly marked one appeared on it.” (See woodcut, copied from
Dr. Hooker’s work). In fact, the terraces have nothing to do
with lakes. They are all the remains of ancient alluvial plains
as we should call them, or of ‘‘river haughs,” as the Scotch would
call them; and ‘the lowest very little above the river” is a river
haugh now in actual formation from the yearly floods of the river,
and from the waste and erosion of the terraces above it. And all
these terraces are at this moment on their way to the alluviums
below, to the delta of the Ganges, to the bay of Bengal, and to the
Diagram of the Glacial Terraces at the Fork of the Yangma Valley (copied, slightly reduced
in size, from Dr. Hooker’s Himalayan Journals, vol. i. p. 219). ‘
Indian Ocean, under convoy of rain and rivers, as much as the run of
every other hill-side is on its way to the valley below, and from the
valley below to the sea at the end of the valley. The terraces are
for atime arrested by the hard gorges ; but as the hard gorges go, the
terraces go. So far Dr. Hooker’s facts and my theories agree. At page
222, ibid., Dr. Hooker tells us that, “being familiar with sea ice and
berg transport during my voyages in the south polar regions,” his
theory is that semitropical Indian land must have been formed under a
polar sea ; and that once upon a time “a glacial ocean stood high on the
Himalaya, made fiords of the valleys, and floated bergs laden with
blocks from the lateral gulleys, which the winds and currents would
deposit along certain lines.”
Yet if I wished for facts in favour of the present erosive powers of
subaérial agents, against that of ancient glacial sea, Dr. Hooker is the
witness that I should call. I might quote from almost every page of
his journey to the Donkia Pass. ‘Thus in vol. ii. page 41, he talks of
“the prevalence of land-slips which descend sometimes 300 feet carry-
ing devastation along their course. They are caused by the melting of
the snow-beds or by the action of the rains on the rocks. This pheno-
Greenwood—On Valley Terraces. 209
menon is as frequent and destructive as in Switzerland.” Again at page
76, “Huge masses were ever and anon precipitated into the torrent
with a roar that repeatedly spread consternation amongst us. During
rains especially, and at night when the chilled atmospheric currents
of air descended, and the sound was not dissipated as in the day time,
the noise of these falls was sufficiently alarming. My tent was
pitched near the base of the cliff and so high above the river that I had
thought it beyond the reach of danger. But one morning I found a
large fragment of granite had been hurled during the night to my
very door ; my dog having had a most narrow escape. I have seen
few finer sights than the fall of these stupendous blocks into the
furious torrent along which they were carried amid feathery foam
for many yards before settling.” Page 78, ‘The rivers were much
swollen, the size and number of the stones they rolled along producing
a deafening turmoil.” Page 97, “ We were suddenly startled from
our repast by a noise like loud thunder, crash following crash and
echoing through the valley. The Phipun got up and coolly said, ‘ the
rocks are falling, it is time we were off, it will rain soon.’ The moist
vapours had by this time so accumulated as to be condensed in rain
on the cliffs of Chomiomo and Kinchinjhow which loosened and pre-
cipitated avalanches of rocks and snow. We proceeded amidst
dense fog, soon succeeded by rain, the roar of falling rocks on either
hand increasing as these invisible giants spoke to one another in
voices of thunder through the clouds. The effect was indescribably
grand.” Page 112, “Terrific land-slips had taken place along the
valley carrying down acres of rock, soil, and pine-forest into the
stream, and I saw one which swept over 100 yards in breadth of
forest. The bridge at the Tuktoong being carried away, we had to
ascend 1000 feet to a place where the river could be crossed. In
many places we had great difficulty in proceeding, the track being
obliterated by the rains and landslips. Along the flats, now covered
with a dense vegetation, we waded often knee deep in mud.” Page
125, “ Broad flats clothed with rhododendron, alternated with others
covered with mud, boulders and débris which had flowed down the
gorges on the west and which still contained trees inclined in all
directions and buried up to their branches. Some of these débacles
were 400 yards across and sloped at an angle of 2° to 8°, bearing on
their surfaces blocks fifteen feet in diameter. They seem to subside
materially, as I perceived they had left marks many feet higher on
the tree trunks. Such débacles must often bury standing forests in
a very favourable material, climate, and position for becoming fos-
silised.” Page 126, “Enormous masses of rocks were continually
precipitated from the west side close to the shed in which I had
taken up my quarters, keeping my people in constant alarm and
causing a great commotion among the yaks, dogs, and ponies.”
Page 127, “Shoots of stones had descended from the ravines.”
Page 128, “Beyond this the path crossed the river and ascended
rapidly over a mile of steeply sloping landslip, composed of angu-
lar fragments of granite, which were constantly falling from above
and were extremely dangerous.” Page 1538, ‘The whole valley was
VOL. IV,—-NO. XXXV. 14
210 Greenwood—On Valley Terraces.
buried under a torrent or débicle of mud and boulders, and half a
mile of its course was damned up into a deep lake.” Page 154, “I
met my friend on the other side of the mud torrent.” Page 184, “I
descended obliquely down a very steep slope over upwards of a
thousand feet of débris, the blocks on which were so loosely poised
on one another that it was necessary to proceed with the utmost cir-
cumspection, for I was alone, and a false step would almost certainly
have been followed by breaking a leg. The alternate freezing and
thawing of rain amongst these masses must produce a constant down-
ward motion on the whole pile of débris (which was upwards of 2000
feet high) and may account for the otherwise unexplained pheno-
menon of continuous shoots of angular rocks reposing on very gentle
slopes in other places.”
So far for the present erosion of rain and rivers. For the present
deposit from them take Dr. Hooker’s description of the Cosi (of which
the Yangma is a tributary) where it runs out of the Himalaya and into
the Ganges, page 86, vol. i. ‘‘Hven at this season (April, the end of
the dry season) the enormous expanses of sand, the numerous shift-
ing islets, and the long spits of mud, indicate the proximity of some
very restless and resistless power. During the rains the scene must,
indeed, be extraordinary when the Cosi lays many miles of land
under water and pours so vast a quantity of detritus into the bed of
the Ganges, that long islets are heaped up and swept away in a few
hours ; and the latter river becomes all but unnavigable. Boats are
caught in whirlpools formed without a moment’s warning, and sunk
ere they have spun round thrice in the eddies.”
As I have said in “Rain and Rivers,” what is everlastingly ascending
through the air as vapour from the sea is everlastingly descending
through the air as rain on the land. This continuous circle of causes »
is always washing the land into the sea. And it is fire only which
keeps our heads above water. Fire is the quarryman that is ever
raising the block, the entire land, above the sea. Rain (with atmo-
spheric erosion) is the chisel, which in the hand of the Almighty
artificer, is for ever sculpturing the block,—that is, shaping the
entire surface of the land, even to the topmost pinnacle of the highest
snowcapped mountain, for snow is frozen rain.
Brookwoop Park, ALRESFORD,
9th March, 1867.
NOTICES OF MEMOTRS.
a
T—A Brier Account or THE “THESAURUS SILURICUS,” WITH A
rew Facrs AND InrereNcEs. By J.J. Biessy, M.D., F.G.S., ete.
[Proc. Royal Society, February 21, 1867.]
HE “Thesaurus Siluricus” is a general view of Silurian life, as
far as now known, in the form of atable. After mentioning the
genus (taken alphabetically), its author, and the date of its establish-
ment, the species are successively named, and treated of under four
or more heads, along one and the same ruled line. First comes the
Notices of Memoirs—Bigsby's Thesaurus Siluricus. 211
part of the stage in which it occurs, then, in a given order, its
author and locality, or localities, in the column indicative of its
proper stage. The “Thesaurus ” contains 7553 species, and there-
fore gives abundant scope for profitable study ; but probably it does
not give the tithe of the whole Silurian life yet lying buried in the
wilds of the Arctic Circle, of Hudson’s Bay, Labrador, the two
Americas, Scandinavia, Australia, India, ete.
The author acknowledges many valuable corrections and sugges-
tions made by Messrs. J. W. Salter and Robert Etheridge, who have
carefully gone over the manuscript: he has also received several
unpublished contributions relating to the Silurian Fauna and Flora
from foreign Paleeontologists. In this brief account of the Thesan-
rus, the author gives numerous tables of the general results arrived
at. One table shows the number of species common to regions very
remote from each other, some of them being antipodal—a fact which
tells the more forcibly from the tenacity with which a large part of
Silurian life clings to locality as well as to horizon. Thus, 179
species are common to Europe and America ; 5 species to Europe and
Australia; 6 species to America and Australia, ete.
Another table gives a synoptical view of Silurian life, with special
reference to vertical range or recurrence. The orders vary greatly
in respect to recurrency. There is none among fossil fish. In
Cystidea it is only 3 per cent., in Gomophoceras, 5 per cent., and
is greatest in Strophomena, beg 31 per cent. The author has
prepared a number of inferences in regard to recurrence. Among
which are the following: Speeies do not often change their horizon,
not even when placed in countries far apart; the same species may be
typical of a single horizon in one country and recurrent in another; the
number of recurrent species measures the amount of change in conditions.
Respecting Extra-Epochal Recurrence, the author states that 133
Silurian species may be regarded as recurring above the Silurian
beds ; with the exception of Chonetes sarcinulata, they all stop within
the Devonian period. The greater part of these recurrents are of
low rank: 20 are Brachiopoda, 11 Zoophytes, 1 Amorphozoon, 7
Gasteropoda, 3 Caphalopoda; 1 Trilobite.
These species are very migratory—-few being found in two epochs
in the same country, but in different countries.
[The Royal Society having voted £200 in the aid of the printing
of Dr. Bigsby’s Thesaurus, we understand the veteran author intends
to incur the further expense (probably £300 additional) himself. ]
IJ.—Ouicocrnz Deprostr 1n Huncary.—At a meeting of the
Imp. Geol. Institute of Vienna, held on February 5th, 1867, M. pe
HanrkeEn read a paper on some Oligocene strata, exposed in a shaft
recently sunk at Sarisap, near Gran, in Hungary. The strata, which
are of brackish and marine origin, attain a thickness of 156 feet.
The brackish beds, consist of sandy plastic clay, characterised by the
presence of Cerithiwm margaritaceum, Melanopsis ancillarioides, Cyrena
semi-striata, Desh., Rosalina Viennensis, d’Orb., and seeds of Chara.
212 Reviews—Billings’ Fossils of Anticosti.
The marine strata overlie those of brackish water origin; they are,
however, separated by a well-marked bed of clay ; one foot in thick-
ness, containing, in great abundance, specimens of Cingula, closely
allied to C. sutura, Fraueuf. A sandstone, 60 feet in thickness, of
marine origin, covers this bed of clay; it contains no Molluscan
remains, but portions of Echinide are met with.—H.B.W.
REVIEWS.
J. —CarTaLoguEs OF THE Sinturtan Fossits oF THE ISLAND OF
ANTICOSTI, WITH DESCRIPTIONS OF NEW GENERA AND SPECIES.
By E. Bruuiyes, F.G.S., Paleontologist to the Geological Survey
of Canada. S8vo., 93 pages. Montreal, Nov, 1866.
HIS brochure is the continuation of the “Paleozoic Fossils,” of
426 pages, by the same author; of which the last sheets
appeared in 1865. It contains descriptions of two new genera and
104 new species of mollusca, crustacea, etc., from the Hudson River,
Anticosti, Clinton, and Niagara groups of Canada, in connection with
general remarks of a novel character upon the synonymy of the
American and English older Palzozoic rocks. Mr. Billings, though
very modest and rarely appearing in public, has within the past ten
years been greatly instrumental in advancing our knowledge of
American Paleozoic geology. It was almost universally believed
that the enormous thickness of strata called locally the ‘Quebec
Group,” and extending from the Gulf of St. Lawrence to Alabama,
was of Middle Silurian age; but Mr. Billing’s descriptions of fossils,
fortified by the opinion of M. Barrande, have convinced the whole
world that the series is not Middle Silurian, nor even the equivalent
of the Lingula flags (Potsdam), but that it forms a new group not
before recognized, of about the epoch of the Lower Llandeilo. An
idea of Mr. Billing’s ability and industry may be gathered from the
fact that he has described not less than 43 new genera and 870
species of new Paleozoic fossils; and there are many others in his
hands awaiting description. It is very creditable to the executive
capacity of Sir W. E. Logan that the Survey under his charge has
collected so many rare fossils, and arranged them in their proper
stratigraphical horizons, or rather intercalated new epochs in the
Silurian almanac. We trust these preliminary notices will be
_ speedily followed by such accurate engravings and elaborate de-
scriptions of the new forms as their importance demands, and such as
will reflect honor upon the liberality of the Canadian Government.
We will now present a table of the revised nomenclature of the
North American older strata, and their synonymy with the English
formations, as enunciated in this pamphlet.
1. Clinton, or divisions three and four of the Anticosti ai U. Ilandovery
2. Anticosti, divisions one and two one 565 20 .. L, Llandovery
.3. Oneida conglomerate, and Medina S.
4, Hudson River and Utica slates ays a oo ... Caradoc
6, Trenton limestone
6. Birds-eye and Black River
Reviews—Billings’ Fossils of Antacosii. 213
7. Chazy limestone os a5 ae ae ae ... U. Llandeilo
8. Sillery
9. Lauzon } Quebec
10. Lévis aes L. Llandeilo
11. U. Calciferous
12. L. Calciferous ... wee ate Use aes ik ... U. Tremadoc
13. U. Potsdam ... aB6 Ms aa aah ue ... L. Tremadoc
14. L. Potsdam... Ses bee mee odo ah .. U. Lingula
15. St. John’s group sce .» L. Lingula
The whole aspect of No. 1 is very much like that of the U. Llan-
dovery, especially in certain Strophomena, Leptena, Pentamerus,
Stricklandinia, Spirifera, Cyrtia, and Leptocelia. The L. Llandovery
is like No. 2, because it contains a curious admixture of both Upper
and Lower Silurian types. No. 10 is connected with the L. Llandeilo
or Skiddaw by a great development of Graptolites. No. 10 carries
a fauna very distinct from Nos. 7 and 12, with which it has been
heretofcre confounded, containing 220 species (51 graptolites).
No. 12 is the original Calciferous Sandstone of N.Y., and finds its
nearest analogue in the Durness limestone of Scotland. No. 16 is
identical with the Lower Lingula flags, as determined by the Parad-
oxides. These are considered to be quite satisfactorily paralleled;
the other groups upon the same lines are supposed to have been
nearly equivalent, because they come between others that are
identical.
The Trenton limestone has been paralleled heretofore with the
Llandeilo, with which it has scarcely any paleontological character
in common. It abounds in Cystidee and Asteride, Rhynchonelle,
Strophomene, and Zoophyta of the group Zoantharia rugosa, and thus
is more nearly allied to the Caradoc. The Sillery and Lauzon
divisions are very sparingly fossiliferous. The stratigraphical
relations of the Lévis formation are best shown in Newfoundland,
where the same fauna as that near Quebec appears in slightly inclined
strata, but above the true calciferous as well as an intermediate
group unlike anything elsewhere known. The Lévis in Newfound-
land is 1400 feet thick ; the Upper Calciferous 1300, and the Lower
Calciferous 1800. The middle group contains the European genera.
Acrotretra, Nileus, Holometopus, and Ampyz, which extend into the
following formations also. No. 13 is what has hitherto been known
as the Potsdam sandstone of N. Y. Can. W., Minnesota, etc. :
Gasteropods and Cephalopods make their first appearance here.
No. 14 is known only in the sandstones and limestones of Belle Isle,
and the “Georgia slates” and “Red sand-rock” of the Vermont
Survey. They are characterised by the presence of Olenellus,
Bathynotus, and certain species of Bathyurus, Conocoryphe, Obolella,
and Camerella. The lowest group (No. 15) ouly contains Paradoatdes.
It has been found near the Atlantic coast in Newfoundland, New
Brunswick, and Massachusetts. In New Brunswick it is 3000 feet
thick and covers other sedimentary deposits, and probably in Massa-
chusetts. It is certainly newer than the syenite of Massachusetts.
It is suggested as worthy of consideration, whether a break in
one country may not be synonymous with a group in another ;
214 Reviews— Traill on Quartz and Opal.
especially as the breaks in England are more numerous, and the
formations less abundant than in America. Until the discovery of
Nos. 8 to 11, no one suspected that the paleontological break between
7 and 12 was of any consequence. Now, it appears that this break
in New York represents three or four large groups of strata 600 to
800 miles away. Much more, therefore, may a break in England
represent a formation in America, and vice versa.
Singularly enough the establishment of a zone of life below the
~ Potsdam of America is, in agreement with the views of Professor
Emmons, who as long ago as 1842 maintained the existence of a
system which he called Taconic, and correlated it with the Cambrian
of England. A part of the strata included in Mr. Billings’ Lower
Potsdam were labelled Taconic by Emmons twenty years ago. A\l-
though many of the so-called Taconic strata are unequivocally Lower
Silurian, the question seriously presses upon us whether Nos. 14 and
15, with perhaps other formations connected with them, ought not
to be called Taconic at the expense of both Silurian and Cambrian.
I..—An ELementary TREATISE ON QUARTZ AND OPAL, INCLUDING
THEIR VARIETIES, ETC. By Grorce Wittiam Trait, G.S.E.
Edinburgh : Maclachlan and Stewart. London: Simpkin, Mar-
shall and Co.
HY this little book has been published we are at a loss to con-
ceive, as it is not written in a popular manner, nor does it fill
any gap in mineralogical literature. Students of mineralogy will
find in the several manuals on this subject, already published, all that
is to be found in this work; and, indeed, in some of them, much
more. In his Preface, the author says that quartz and opal hold a
prominent place in most collections, and are well suited to form
an independent treatise. We agree with him, provided always
that the treatise includes a complete epitome of all the investi-
gations that have been made upon the subject up to the time of
its publication. But in this book no mention is made of the re-
sults of the very complete studies of M. Des Cloiseaux upon the
crystallography and other physical properties of this mineral, which
is to be found in his “ Manuel de Mineralogie,” the first part of
_which was published in 1862: and more in detail in Vol. xlv.
of the “ Annales de Chimie et de Physique,” and in various me-
moirs presented to the Academy of Sciences of Paris; nor to the
researches of Dr. H. Weiss on the crystallisation of quartz—all of
which would have afforded materials for some very instructive
chapters. The former eminent mineralogist has arrived at the con-
clusion that a simple crystal of quartz is of very rare occurrence.
He shows that the apparently simple crystals from Buxton in Derby-
shire, Dauphiné, Traversella, and other localities, are really macles.
The important phenomena of circular polarisation, so peculiar to
quartz, and the curious structure of amethyst, the author dismisses
in a few sentences, while the interesting varieties called right and
left handed quartz are not even mentioned. The various minerals
Reviews—Traill on Quartz and Opal. 215
enclosed by quartz during the process of crystallisation are simply
enumerated, no attempt being made to explain the probable mode in
which such hair-like crystals as those of rutile, asbestos, etc., are en-
closed, those of the former often crossing each other at various angles.
In the British Museum is exhibited a very instructive series of crystals
and masses of quartz with enclosed minerals, conspicuous among
which is a large crystal, said to be from Brazil, enclosing a large
cavity containing a fluid, in which are some small loose crystals of
iron pyrites. The same crystal also encloses several distinct doubly
terminated crystals of quartz, and the impressions of some large
tabular crystals which were probably mica. Another interesting ex-
ample of an Enhydros in the same collection is a small nodule of
translucent chalcedony about two and a half inches long by one and
a half wide, which is three parts filled with a fluid, no doubt water.
This was found near Salto, in Uruguay, by W. G. Lettsom, Hsq., and
probably represents one stage in the formation of agates.
Small but perfect rhombohedrons of a red colour have been found
in the calcareous geodes, ‘“ potatoe-stones,”’ of Somersetshire, and en-
closing peroxide of iron, at Wolf’s Island, Lake Onega, Government
of Olonetz, Russia. The author places silicious sinter with quartz,
whilst all reliable analyses show it to be hydrous; and its nearly
complete solubility in caustic potash. together with its low density,
point to the species opal as its*correct place. He also states that
aventurine is often imitated in glass. Is he not aware that the glass
is the true aventurine, the name being adopted for a variety of quartz
which was somewhat similar in appearance? A Frenchman dropped
some copper filings accidentally, par aventure, into a fused vitreous
mixture, and gave the name aventurine to the glittering mass which
resulted from this accident.
_ As we have shown, this book is of no value to the mineralogist,
though the author might have produced a really useful work by
giving a little more time and labour to his subject, so as to include
the results of the labours of those who have, during the last ten or
fifteen years, made these minerals their special study.
REPORTS AND PROCHHEDINGS:
—_—_—~>———_
GroLocicaL Socrety or Lonpon.—March 20, 1867.—Warington
W. Smyth, Esq., M.A., F.R.S., President, in the chair. The follow-
ing communications were read :—
1. “Report on recent discoveries of gold in New Brunswick.”
By W. 8. Shea, Esq. Communicated by the Right Hon. the Harl of
Carnarvon.
Mr. Shea gave in his report a detailed account of his explorations
into the gold-bearing gravels of certain river valleys in the counties
Victoria, Northumberland, Carleton, and York, in Central New
Brunswick. He had been enabled therefrom to draw the following
inferences :—(1) That the gold in these alluvial deposits is derived
from the quartz-veins penetrating the rock of the district; (2) that
216 Reports and Proceedings.
the gravel, which contains pebbles of all sizes, was derived from the
disintegration of the rocks of the district; and (3) that, judging
from the richness in gold of paying drift in California, it is probable
that these auriferous gravels will pay also.
2. “On the discovery of Coal on the Eastern Slope of the Andes.”
By W. Wheelwright, Hsq. Communicated by Sir R. I. Murchison,
Bart., K.C.B., F.R.S., ete.
In this paper the author reported the occurrence of beds of Coal
on the eastern slope of the Andes, between the cities of Cordova
and San Juan, about twenty-five leagues east of the latter city.
3. “On the presence of Purbeck Beds at Brill, Buckinghamshire.’
By the Rev. P. B. Brodie, M.A., F.G.S.
The existence of the Purbeck-beds at Brill not having been yet
accurately determined, the author recorded their occurrence in that
locality, which he had been able to ascertain by finding blocks
containing several species of Purbeck freshwater shells, especially
Paludina subangulata and Cyrena media.
4, “On the Lower Lias, or Lias-conglomerate of Glamorgan-
shire.” By H. W. Bristow, Esq., F.R.S., F.G.S., of the Geological
Survey of Great Britain.
The object of this communication was to show that the more or
less conglomeratic strata immediately underlying the ordinary Lias
limestone on the coast of Glamoérganshire, between the River
Ogmore and Dunraven Point, do not belong to the Rheetic series, as
has been supposed, but to the Lias.
The Sutton-stone of Sutton and the so-called Southerndown series
(seen in the cliffs under the hamlet of that name) constitute, in
reality, but one series, the stratigraphical position of which is proved
by reference to the sections at Cwrt, near Langan, at St. Mary Hill
Common, west of Trymynydd, and at the Stormy Cement Works,
where it immediately overlies the Rheetic series, while its paleeonto-
logical affinity with the Lias is proved by the occurrence throughout
its entire thickness of the most characteristic shells of that formation,
viz., Gryphea incurva, Ostrea Liassica, Lima gigantea and Ammonites.
These conglomeratic strata extend over a large area from Sutton
to beyond Cowbridge ; and wherever the Lias rests upon Carboni-
ferous Limestone or Magnesian Conglomerate, it assumes an ab-
normal lithological character, and becomes more or less conglomeratic.
The replacement, in this district, of the ordinary calcareous and
argillaceous sediments, of which the Rhetic and Liassic series are
usually composed, in the former case by sandstones, and in the
latter by conglomerates, indicates that they are the near-shore and
shallow-water deposits of an area that now forms part of South
Wales, and which was partially undergoing slow depression during
the deposition of the Lias.
After noticing the occurrence of lead-ore (Galena) in these beds,
the term Lias Conglomerate, originally applied to them by Sir
Henry De la Beche, was proposed as being sufficiently precise and
distinctive, the name Infra-lias, by which they are sometimes denoted,
being objected to, as being both vague and misleading.
Geological Society of London. 217
5. “On Abnormal conditions of Secondary Deposits when con-
nected with the Somersetshire and South Wales Coal-basins; and
on the age of the Sutton and Southerndown series.” By Charles
Moore, Hsq., F.G.S.
The author first describes the geological constitution of the Mendip
Hills, which, in his opinion, were upheaved by the intrusion of a
basaltic dyke (now noticed for the first time) during the period of
the Upper Trias. The Mendip chain proved an island-barrier to the
incursion of the deeper sea-deposits of the south, on which lived the
Microlestes and other terrestrial animals. Along the south side of
this barrier shore-deposits were formed, the “Carboniferous Lime-
stone” constituting the floor of the ocean at that time.
He then instituted a comparison between the Rhetic and Liassic
formations within and those without the Somersetshire coal-basin.
The thickness of the beds, from the Trias to the Inferior Oolite, was
stated to be, outside the coal-field, 3320 feet, whilst inside it was
only 169 feet. These results were obtained from an examination of
numerous sections, which were described in detail by the author.
After considering the horizontal deposits beyond the Mendips, and
the unconformable conditions within its coal-basin, the author dis-
cussed the abnormal conditions which are presented by deposits of
the same age, when they are intimately connected with the “Car-
boniferous Limestone.” In the Charterhouse lead-mine a deposit of
clay, twelve feet in thickness, and containing Liassic shells, was stated
to occur at a depth of 260 feet in the Carboniferous Limestone.
Among the organic remains, three species of terrestrial shells,
referable to the genera Helix, Vertigo, and Proserpina, and a Chara-
seed, were discovered.!
The author concluded by pointing out the peculiarities presented
by the Liassic strata in Glamorganshire, with special reference to the
stratigraphical position of the Sutton Stone and the Conglomerates
of Brocastle, ete. .
IIl.—April 8, 1866.— Warington W. Smyth, Esq., M.A., F.R.S.,
President, in the Chair. The following communications were read :
1. “Remarks on the Drift in a part of Warwickshire, and on the
evidence of glacial action which it affords.” By the Rev. P. B.
Brodie, M.A., F.G.S.
The later Drift-deposits in the district treated of occur along the
valley of the Avon, and consist of the usual sands and gravels, with
Mammalian remains; but as yet no Flint Implements have been
discovered in them. The author enumerated the different kinds of
rock represented by pebbles or fossils in the gravel, and referred to
the abundance of flints, and the occasional occurrence of pieces of
chalk in the gravel as proof that their mode of conveyance was by
icebergs, unless it be conceded that the Cretaceous formation at one
time had a much further extension northwards. The abundant
1 Since the reading of this paper, Mr. Moore writes me (April 7th), ‘ Additional
evidence in confirmation of a Mendip land-area has turned up, namely, shells of
Planorbis, Valvata, and Hydrobia ; also from the Charterhouse mine.” —Eprr.
218 Reports and Proceedings.
quartzose pebbles occurring in the drift of Warwickshire have re-
cently yielded fossils identical with those occurring in the pebbles at
Budleigh Salterton ; and the author suggests that they had a similar
origin to those in Devonshire.
2. “On the dentition of Rhinoceros leptorhinus.’” (Owen). By
W. Boyd Dawkins, Hsq., M.A. (Oxon.), F.G.S.
The Pleistocene species of Rhinoceros in Britain are four in
number: R. tichorhinus, Cuv.; R. megarhinus, Christol ; R. Htruscus,
Fale.; and R. leptorhinus, Owen [= R. hemitechus of Falconer ].
The latter of these is characterized by the possession of a partially
ossified septum between the nares, and by the slenderness of its
bones. In common with the other three it was bicorn. Its upper
molar series, as compared with the megarhine, is characterised by
the following points :—by the rugosity of the enamel surface; by
the development of a third costa on the posterior area of Pm. 3, 4;
by the concavity of the base of the ewternal lamina; and by the
more vertical direction of the inner side of the colles. The absence
of the anterior combing plate and the stoutness of the guard are
among the points that separate it from the tichorhine molars. The
species does not seem to have existed in Britain before the
great Glacial epoch, the remains from the Forest-bed, attributed to
it by Professor Owen, viewed by the light of other specimens,
turning out to belong to R. Hiruscus. It is associated with the
tichorhine species in Wookey Hole Hyzena-den, with that and the
Megarhine in the Lower Brick-earths of Crayford, in Kent. Ina
word, there is ample evidence to prove that it was coeval with the
Mammoth and tichorhine Rhinoceros, that it ranged from Yorkshire
through the eastern counties into South Wales and the south-west of
England, and that it was very inferior to those animals in point of
number. Its nearest living analogue is the bicorn Rhinoceros of
Sumatra. The dentition both of the tichorhine and leptorhine
species agrees remarkably in one point, that it is more specialized or,
in other words, more closely allied to living forms than that of the
megarhine, a fact that seems to the author to imply that both came
into being after the less specialized Rh. megarhinus had ceased to exist.
3. “On the strata which form the base of the Lincolnshire
Wolds.” By John W. Judd, Esq., F.G.S.
After giving a sketch of the previous very scanty literature of the
subject, the author proceeded to describe the outcrop and the various
outliers and inliers of the ‘‘ Hunstanton Red Limestone,” which in
this district serves as a well-marked datum line in the series of
strata. It was shown that this bed, while maintaining much
uniformity of lithological and paleontological characters, undergoes
a regular attenuation southwards, being 30 feet thick at Speeton, 14
feet and upwards in Lincolnshire, and 4 feet at Hunstanton, thinning
out entirely about 12 miles south of the last-mentioned place.
In the second part of the paper a general sketch of the Chalk
formation in Lincolnshire was followed by detailed descriptions of a
number of red beds, previously confounded with the Hunstanton
Limestone, but now shown to be intercalated in the series of the
Edinburgh Geological Society. 219
Lower Chalk. A typical section made at Louth was then compared
with the grand natural section at Speeton Cliffs, as described by the
Rev. T. Wiltshire, F.G.S.
The extensive deposits underlying the Hunstanton Limestone
were described as follows :—I1st, Ferruginous sands (unfossiliferous).
2nd, a series of limestones, sandstones, and clays, containing a large
and interesting suite of fossils, with an undoubted Neocomian facies,
but presenting greater affinities with the faunas of certain conti-
nental deposits than with that of the English Lower Greensand.
For this formation the provisional name of “The Tealby Series” was
proposed. 38rd, another and thicker series of sands. In its north-
ward development, the Tealby series was described as furnishing
beds of ironstone (often of Oolitic structure and of considerable
economic value), and finally as graduating into the upper part of the
Speeton clay; while, in tracing it southwards, it is found to become
almost wholly arenaceous,
The author gave lists of the fossils of the different beds, and
described the numerous faults, etc., of the district, which he illus-
trated by a map and numerous sections. He concluded with some
remarks on the age of the various beds, and on the causes of the
remarkable red colour of some of them.
An appendix, containing remarks on some of the fossils, showed
that the following well-known species of Sowerby, Ammonites pli-
comphalus, Pecten cinctus, and Lucina crassa, are Neocomian, and
not Jurassic forms, as has hitherto been supposed.
The fourth ordinary meeting of the EpinsurcH GEOLOGICAL
Socrety was held on February 7th, in their rooms, 5, St. Andrew
Square,—Mr. David Page, President, in the chair. Dr. Henry
Campbell read a paper on “The Rhizopoda, and their importance
in geological formations.” The skeletons of one order of those
animals, the Polythazamia, were abundantly procured on almost
every sandy shore, and the fragile shells formed the principal con-
stituents of several very important geological formations. Mr.
Andrew Taylor read a paper on “The past, present, and future of
the Scotch and Welsh mineral oil supplies.”
The fifth ordinary meeting of this society for the session was held
on February 21st, in their rooms, No. 5, St. Andrew Square—Mr.
Thomas Wallace, in the absence of the President, in the chair.
Mr. George Lyon, the treasurer, read a paper “On the Shell Mound
which was lately excavated by the society in Dalmeny Park.” He
showed that the mound in question was of very modern origin, and
contained nothing of any interest either in a geological or an archeo-
logical point of view.
Mr. John Henderson read a notice, which was illustrated with
specimens and drawings, of ‘Three Species of Trilobites from the
Silurian Beds of the Pentland Hills.” They consisted of Phacops
Stokesti, Calymene Blumenbachii, and a species, not yet well deter-
mined, belonging to the genus Encrinurus.
220 Reports and Proceedings.
Mr. D. J. Brown then gave a short notice of the discovery of
specimens of Strophomena Walmstedii in the Pentlands. This species
is new to Britain. It has been found, however, in Sweden.
The concluding paper was on “The Silurian Beds of the Pentland
Hills,” by Messrs. D. J. Brown and John Henderson. A descrip-
tion was given of the section of the North Esk Reservoir, and more
than a hundred species of fossils from these beds were exhibited to
the members of the society. The authors of the paper gave their
opinion as to the age of the beds, stating that they considered them
to be both of Wenlock and Ludlow age. They combated Mr.
Geikie’s opinion as to the red beds being the lower portion of the
Old Red Sandstone, and as they had both obtained Ludlow fossils
from them, they had arrived at the conclusion that there are a series
of red beds included in the Ludlow portion of the Silurian formation
in the Pentlands. They also pointed out an error in the Government
geological map of the district. The red beds in the maps are
marked as if cut off in the form of a triangle, but Messrs. Brown
and Henderson had traced them by cutting through the soil on the
hill sides, until they considered themselves justified in concluding
that those beds stretched across the whole area, in the same manner
as the other beds.
GEoLoGicaL Society or GLAscow.—This society met in Anderson’s
University, on the evening of 7th March.—Mr. Edward A. Wunsch,
Vice-President, in the chair.
On the motion of the chairman, seconded by the Rev. Henry W.
Crosskey, Vice-President, Dr. John Young, Professor of Natural
History in the University of Glasgow, was elected President of the
society, in’room of the late James Smith, Esq.. of Jordan-hill, F.R.S.
Dr. Young said he accepted with pride the honour which the
society had conferred on him. He had, though but recently a
stranger in Glasgow, received what under other circumstances he
might have hoped for as the reward of services rendered. The
society had, as it were, taken him on trust, and he would earnestly
endeavour to justify their generous confidence. After alluding to
the former school of geology in Scotland, and its influence on the
present tendencies of the science, he said it was small gratification
to our national pride that Scotsmen were so prominent in England,
while in Scotland there exists as yet neither school nor teacher. In
the honest work of such a society as that of Glasgow the means
exist for restoring to Scotland somewhat of its former prestige, and
he (Dr. Young) was much gratified at the opportunity now offered
him of furthering this desirable object. In taking the chair, Dr.
Young returned sincere thanks for the high personal compliment
bestowed on himself, and for the tacit appreciation thus shown of the
duties upon which he was about to enter elsewhere—duties which
the society had indicated its willingness to aid him in discharging,
while it had added one more to the ties which drew the University
and the city closer together, to the mutual benefit of both.
Mr. James Bennie exhibited a number of small pebbles and
Geological Society of Glasgow. 221
nodules, chiefly of limestone, which he had obtained from a bed of
black bituminous shale, exposed at various quarries in the district of
Hast Kilbride ; many of them were perforated with holes, resembling
in size, Shape and depth, those formed by certain of the mollusca.
Mr. Bennie also exhibited, from the shales of the same district,
what he considered to be specimens of very minute Crinoids.
Professor Young and Mr. John Young read a joint paper on
“Local Unconformity, as illustrated in the Carboniferous Rocks near
Bishopbriggs.” In Coltpark Quarry Mr. Young had discovered a
series of vertical beds beneath the nearly horizontal main post of the
Bishopbrigegs sandstone ; and in this paper the authors described and
illustrated by diagrams the detailed survey they had made of the
neighbourhood. They considered that the vertical beds are a part
of those lying beneath the Cowglen limestone; that about twenty-
five feet of strata have been removed by denudation ; and that the
extremely Jocal nature of the disturbance is such as might be due to
an intrusion of greenstone, of which two examples are seen not far
off. They concluded with some general remarks on local uncon-
formity without disturbance, as abundantly illustrated in the same
district, and on the uses of the terms unconformity and overlap.—J.A.
II. March 28th.—Dr. Young, President, in the chair.
T. Rupert Jones, Professor of Geology, Royal Military College,
Sandhurst ; James W. Kirkby, Sunderland; Henry Woodward,
F.G.S., of the British Museum; and J. H. M‘Chesney, Professor of
Geology, University of Chicago, were elected honorary members ;
and Messrs Andrew Mackie, M.D., Abbotsford Place, C. B. Aikman,
writer, St. Vincent Street, Alex. Smith, Little Hamilton Street, and
John Anderson, painter, St. Enoch Square, were elected resident
members of the Society.
Dr. Young exhibited specimens of a variety of Megalichthys, which
in Scotland occurs only at Quarter, near Hamilton, and has, he be-
lieves, a similarly restricted range in North Staffordshire, which
contrasts with the wide distribution of M. Hibberti. The scale is not
enamelled, and is thickly covered with alternating larger and smaller
tubercles, giving a very characteristic and elegant ornamentation.
He exhibited the scales of genera allied to Megalichthys, and pointed
out the difficulty of determining genera from single scales, the inter-
mediate varieties between distinct types being numerous. Only a
few scales of the Quarter fossil have been found, but further dis-
coveries may justify its erection into a separate genus; meanwhile
it is best to retain it as a species.
Mr. J. Wallace Young read a paper “‘On some Local Sandstones.”
The results may be shortly summed up as follows :—1st, That in
the greater number of sandstones examined, the cementing material
consisted of carbonates; 2nd, That very considerable quantities of
the carbonates of iron and magnesia frequently accompanied the
carbonate of lime, although no definite ratio seemed to exist be-
tween them; 3rd, That these sandstones were harder the greater
the proportion of carbonates they contain ; 4th, Mica was found to be
222 fteports and Proceedings.
present in nearly all those examined, and, with one exception, was
of the white variety ; 5th, Soluble silicates were only found in three
varieties, in any quantity, all three belonging to the Old Red Sand-
stone ; 6th, That the different shades of colour seen in those sand-
stones belonging to the last-mentioned rocks appeared to be due
solely to the peroxide of iron, and that the white rings ‘and spots so
often observed have resulted from the reduction and subsequent
removal of the greater part of this iron.
Dr. Young concluded his remarks on the Osteology of Fishes on
which he had previously lectured (14th March.) In that lecture he
pointed out the arrangement of the facial bones in the osseous and
Ganoid orders among living fishes, and indicated their homologues,
so far as they had been established, in the higher vertebrates. He
then described the structure of the head of Megalichthys, and, compar-
ing it with that of Polypierus and Amia (two living ganoids found in
Egypt and the Southern States of America), he explained the close
connection which had been established between the former living
genus and the extinct family in which Megalichthys is included. On
the present occasion he briefly summed up the grounds on which
Paleoniscus and the majority of Mesozoic fishes are included in the
same family with Lepidosteus, the North American ganoid, and
referred to the new genus Calamoichthys, of J. A. Smith, as repre-
senting, in the absence of the ventral fin, Platysomus and its allies.
He then showed that the progression which had been asserted as
observable among fish from Paleozoic to modern times was not sup-
ported by the facts, since there was reason to believe that osseous
fishes existed in the Old Red Sandstone, and, in the structures just
described, presented as high a stage of development in ancient as in
recent times. He then discussed the forms of the caudal fin, and,
illustrating this subject from the researches of Koélliker, Huxley, and
others, showed that ‘ homocercal ” was a term liable to create confu-
sion, since the majority of osseous fishes are as “ heterocercal”’ as
the sharks. The unequal division of the tail presents several degrees
both in extinct and living ganoids, which might be described as
‘“‘heterocercal equilobate, or inequilobate.” ‘‘ Diphycercal,’”’ M‘Coy’s
term, should be restricted to truly homocercal tails, as of Celacanthus
and Diplopterus. 'The difficulties of classifying fishes were spoken of
in reference to the arrangement according to scales, as proposed by
Agassiz ; and the true principle, that of grouping according to the
sum of characters explained.—J.A.
Montreat Narurat History Socrrry.—The first lecture of the
Somerville course for the present season was delivered on Thursday
evening, January 17th, by Dr. P. P. Carpenter, who chose for his
subject, ‘The works and ways of shell-fish.”
II.—On January 26th, the President (Dr. Hunt) in the chair.
Principal Dawson then read a paper “On certain discoveries in
regard to Hozodén Canadense.”
The paper was preceded by one from Mr. H. G. Vennor (of the
Montreal Natural History Society. 223
Canadian Geological Survey), relating the exact circumstances under
which the specimen to be described was found, and giving a detailed
description of a section of the rocks from which the fossil in question
was procured.
Principal Dawson exhibited a photograph of a remarkable specimen
of EHozoén Canadense, found during the past summer in the Lauren-
tian limestone of Tudor, Canada West, by Mr. Vennor. The rocks at
Tudor and its vicinity, which, according to the observations of Mr.
Vennor, are Lower Laurentian, have experienced less metamorphism
than is usual in formations of that age. And this peculiarity gives
especial interest to the present specimen, which is contained in a rock
scarcely altered, and in a condition not essentially different, from
that of ordinary Silurian fossils.
The matrix is a coarse laminated limestone of a dark colour, and
containing much sand and finely comminuted carbonaceous matter.
The fossil itself is of a flattened clavate form, about six and a half
inches in length, and with the septa of its chambers perfectly pre-
served, exhibiting on one side a well-defined marginal wall, pro-
duced by coalescence of the septa, and apparently traversed by
small orifices. Under the microscope the minute structures of
Eozoin Canadense can be detected, though less distinctly perceived
than in some of the specimens mineralized by serpentine. In some
of the chambers there are small amorphous bodies containing pointed
silicious spicules, which seem to be the remains of sponges that have
established themselves in the cells after the animal matter of Hozoén
had disappeared.
The importance of this specimen was pointed out as establishing
the conclusions previously arrived at from the study of the remains
of Hozoén included in the serpentinous limestones, and as overthrow-
ing the objections raised in some quarters to the organic origin of
Eozoén. The specimen will be taken to England by Sir W. E. Logan,
and full details of its characters will be communicated to the Geolo-
gical Society, along with some other recent discoveries, tending to
the establishment of a second species of Hozodn.
Dr. Hunt, in some remarks made at the conclusion of the paper,
gave Mr. Vennor due credit for establishing the occurrence of
Laurentian limestones at Tudor, and stated that the degree of meta-
morphism of rocks was not necessarily dependent upon the age of the
formation.
III.—One of the course of six free lectures annually given by the
Natural History Society, was delivered on February 9th, by Dr. T.
hae Hunt, F.R.S., President of the Society, to a full and attentive
ouse.
The subject announced was ‘‘The Origin of Continents.” The
lecturer proceeded to describe briefly the great facts with regard to
the outlines of continents and oceans. ‘The mean depth of the
waters, which cover eight-elevenths of the globe, was about 10,000
feet, and the mean height of the land about 1,000 feet. If we suppose
a globe eighty feet in diameter, the deepest parts of the sea would be
224 Reports and Proceedings.
represented on it by depressions of half'an inch, and the highest
mountains only about five-eighths, while the Alleghanies would not
rise much over one-eighth of an inch above the mean level. Going
back to the origin of the present continents, built up of sedimentary
rocks,—sand, clay and limestone,—often more or less altered and
crystallized; the lecturer described the condition of the primitive
globe, a mass intensely heated, but solid to the centre, surrounded
with an irregular surface partially covered by water. This, wearing
down the crust, would form sedimentary rocks, which softened in
their lower parts by the central heat, would permit irregular move-
ments of depression and elevation of the superficial crust, consequent
upon greater weight in one place, and less weight in another. ‘To
this was conjoined the contraction of the whole outer sedimentary
envelope of the globe. The action of atmospheric and other agencies
in slowly wearing away the earth’s crust was dwelt upon, and it was
explained that the matter thus carried down into the sea is dis-
tributed by great ocean currents. These are due to the different
temperatures of the Equator and Poles, but are modified in their
course by the rotation of the earth, giving the northern hemisphere
hot and cold north-east and south-west currents, and in the southern
hot and cold south-east and north-west currents. Besides, there is a
great equatorial current from east to west. ‘To these directions all
the great mountain chains conform, with some variations from local
causes. The lecturer then explained that the history of mountains
was the history of continents, since mountains are but portions of
continents which have escaped the eroding action that sooner or
later breaks down the solid lands. He illustrated this part of the
subject by reference to the geology of eastern North America, and
showed how in early times the great ocean currents had spread, in a
north-east and south-west direction, a vast mass of sediment along
the eastern part of the continent, which now forms the great Ap-
palachian belt, partly cut away, but still leaving ridges of mountains.
In conclusion, the lecturer observed that the field opened by his
theme was far too vast for a single lecture, and that he had been
obliged to omit many important points which were required for the
full elucidation of this subject.
TV.—The annual Conversazione of this society took place on
February 18th. Geology, Paleontology, Zoology, Botany, Chemistry,
Physical Science, and the Fine Arts, were duly represented.
The President of the society, Dr. T. Sterry Hunt, F.R.S., wel-
comed, in the name of the society, the assembled guests, and alluded
briefly to the general object of these annual conversaziones. He
alluded to the services of their scientific curator, Mr. J. F. Whiteaves,
to whose industry and extensive scientific knowledge the society
were deeply indebted; and then proceeded to make some remarks
on meteors, preliminary to an explanation of the periodic nature of
the November meteors; he defined two classes, the stony or metallic
aerolite, or fire balls, and the shooting stars; the first comparatively
rare, and the last very common, and of daily occurrence.
9
Montreal Natural History Society. 265
From good data, Professor H. A. Newton, of Yale College, has
calculated that they proceed from an elliptical ring, which has a
period of revolution of 281 days, and through which the earth
passes about this time, occupying three or four days, showing that
this belt must be several millions of miles thick, and must contain,
at a moderate calculation, more than three hundred millions of small
meteoric bodies.
Now the earth at this time is advancing through space at the rate
of about two millions of miles a day, and the bodies of this ring,
having a retrogade motion, enter our atmosphere with immense
velocity. The ordinary height of these luminous meteors is from
fifty to seventy miles, and the rare atmosphere at that height opposes
sufficient resistance to these rapidly moving bodies to heat them to
whiteness, and even convert them into vapour. The latent heat of a
siven bulk of this rare atmosphere is as great as that of the same
bulk of more dense air near the earth, and calculations show that a
meteor, moving at a rate of only ten miles a second, or less than
one-half the ordinary velocity of these bodies, at a height of thirty-
four miles, would in one second’s time evolve heat enough to make
its mass white hot. The real luminous appearance comes, however,
from the atmosphere condensed before the moving body, and from
the matter of this converted into gas by the intense heat. If not
already dispelled in vapour, these bodies,on reaching the lower region
of the air, cease to be luminous from the very density of the
atmosphere.—Montreal Daily News and Gazette.
a
CORRS 2] @aN> aN @ aba.
ON THE ALLEGED HYDROTHERMAL ORIGIN OF CERTAIN
GRANITES AND METAMORPHIC ROCKS.
To the Editor of the GnotocicaL MaGazine.
Dear S1r.—The letter of Mr. James Geikie which appeared in
your last number obliges me to send a few lines in reply.
I may premise by stating that my communication, “ On the alleged
hydrothermal origin of certain granites and metamorphic rocks,” owed
its appearance in print, solely to the fact of the Memoirs therein
referred to, having emanated from the pen of a member of the
Geological Survey of Great Britain, and it was the official position of
the writer which alone caused his productions to be submitted to the
severe, but just, criticism which therein appeared.
Mr. James Geikie, in his reply, takes me to task for so con-
founding him with the Survey; independent of his being actually
an officer of the Survey, it will be seen, upon reference to his own
memoir,’ that after stating that the Geological Survey (represented
by himself and his colleagues, Dr. Young, and Mr. A. Geikie) was in
1865 extended to the district in question; Mr. James Geikie an-
nounces the object of his memoir in the following words :—
“With Sir Roderick Murchison’s permission, some of the more
1 Quart. Journ. Geol. Soc., vol. xxii, p. 514.
VOL. IV.—NO, XXXV. 15
226 Correspondence.
interesting results obtained during the progress of the Survey are
here described.”
In my communication, I based my remarks upon principles which
the entire geological world will unanimously concede to me, viz :—
That in an investigation of admittedly one of the most intricate and
abstruse problems which form the subject of geological research, it
is absolutely, nay, vitally, essential that each step forward in the
inquiry should be tested with the utmost care and suspicion ; that
each argument, derived from the collateral sciences, should be
thoroughly examined into, as to soundness; and that no misunder-
standing should be allowed to arise from the use of a bad or
indefinite terminology.
From the tenor of Mr. James Geikie’s remarks, may it not fairly
be asked :—To whom does he address himself? or, for whom is
he writing? whether to beginners in the science, or to the Geo-
logical Society of London? If to the former, may it not be inquired,
whether the subject is not, in itself, too abstruse for beginners, and
should not the most scrupulous care be taken, that nought but
admittedly sound arguments, nomenclature, or similes, be made use
of; for all know how exceedingly difficult it is to eradicate incorrect
notions, when once they get into the head of a beginner in science.
If to the latter, to whom his first memoir is especially addressed,
are not geologists, when an author ventures to bring novel and
sweeping’ views in the most abstruse departments of the science
before a tribunal supposed to represent the highest geological talent
of the empire, fairly entitled to demand that, at least, his premises
are not indefinite or unsound, and that his phraseology is not, as
admitted, “‘ careless and unguarded.”
After a careful perusal of Mr. James Geikie’s reply, I cannot find
anything therein which in any way disproves, or even shakes, the
weight of my arguments ; but, from that gentleman’s defence, I can
clearly understand, that the time has come when it will not do to
mince matters in this discussion ; for, as the reader will perceive, it
is not against Mr. James Geikie that I am fighting, but against the
system which he now attempts to defend.
Glad should I be if I could (as Mr. James Geikie would charge
me with) believe “that the terminology of petrology is as fixed as
that of the exact sciences ;” what I do, however, believe is, that 7
ought so to be, and further, that it is a disgrace to the present state of
geological science that it is not so.
No person is more fully aware that “looseness” in petrological
nomenclature is unfortunately the rule, not the exception; and that
ceologists may continually be found mapping and writing of totally
different rocks, under one and the same name; what 1, however,
would infer therefrom is, simply, that it is high time to reform.
In what, now, does Mr. James Geikie’s defence consist ? Upon
perusal of his reply, it will at once be perceived that it is, in major
part, a simple “tu quoque” to other (often eminent) writers upon
the subject ; an argument which may be very effective against these
gentlemen, but one which the rest of the geological world will not
Correspondence. 227
accept, as either exculpating an officer of the Geological Survey, or
acquitting him of following an example patently bad.
In such instances one mis-statement becomes a precedent for
another, and although such precedents may fairly be brought forward
in extenuation, still they do not, as Mr. J. Geikie would have us
believe, entirely exonerate himself.
For this purpose, he quotes names of the highest authority in other
branches of geology, as Lyell, Phillips, and Dana. I would, however,
not do Sir Charles, our great expounder of geological principles, the
injustice to suppose that he would attempt to enforce strictly the rock
definitions contained in chapters xxviil. and xxxili. of his Elements
as a standard for exact petrological comparison ; nor, do I imagine,
would the cautious Professor Phillips think it fair-play if the chapter v.
of his Manual was to be dissected for similar purposes; and still less
would the celebrated mineralogist Dana commit himself, without
reserve, to the rock definitions given in p. 246, vol. u., of his
Mineralogy, where he does happen to allude to mica-slate as a gneiss
with a distinctly foliated structure.
In questions of petrology, instead of quotations from works on
general or elementary geology, I had expected to have been referred
to works specially devoted to that subject; but, with the exception
of the recent translation of Cotta, on the classification of rocks, a
work acknowledged not to fulfil the requirements of the present
state of science,! Mr. James Geikie does not even allude to them.’
Mr. James Geikie deprecatingly expatiates on the profound know-
ledge of chemistry, mineralogy, etc., which he declares I woutd
require of the geologist, evidently not wishing to acknowledge that
the pith of my argument was but intended as a warning to those
geologists who really possessed no knowledge of these sciences not
to expose themselves to just criticism by filling their pages with
unwarranted or unsound chemical or other data or hypotheses.
The geologist who enters into the details of any one department
of his science, will regard “ Admirable Crichtons” as fossils from
a very early period of science, for nobody knows better the ab-
surdity of any man, however talented, pretending to be an authority
on all branches of any one science; for in this century every science
presents far too wide a field for any single labourer to cultivate all
parts of it properly, or in other words, to be at the same time “‘ well
up” in every department.
From time to time, in geology, as in every other science, the ap-
pearance of a generalising mind like Lyell is required to take up the
accumulating chaos of facts, and mould them into shape: the true
steady advance of geological science depends, however, in greater
part upon the labours of the working bees who provide these data,
by (without attempting to grasp too much) devoting their energies
to the minute and careful investigation of some special branch, how-
1 Vide Reviews in Grotoctcat Macazrinz and Atheneum.
2 There is no want of special works on this subject ; to witness the publications of
Blum, Brongniart, Coquand, D’Halloy, Erdman, Leonhardt, Mayer, Macculloch,
Pinkerton, Roth, Senft, Serres, Zirkel, ete.
228 Correspondence.
ever small, of the science, briaging in to their assistance a sound
knowledge (acquired by patience and labour) of so much of the
collateral sciences, as specially applies to the chosen department of
inquiry: without, however, attempting or pretending to the im-
possibility of being at the same time profound in such science.
Mr. James Geikie does me injustice in making me appear to say,
that the development of crystalline rocks from aqueous strata “is a
notion supported only by his assertion.” How could I give that
gentleman credit for an idea far older than either of us, and cases of
which I have myself years ago examined and described.’ Upon
reference to my communication, p. 57, it will be seen that I simply
record a decided protest against the statement made by Mr. James
Geikie, when he writes—
' “It is certain, however, that rocks, such as diallogite, hypers-
thenite, diorite, syenite, or even granite itself, can be developed
directly from aqueous rocks,” ete.
If instead of “certain,” the word possible or even probable had
been used, I should not have objected, and now repeat that a very
careful inquiry into the literature of the subject, does, I consider,
fully warrant me in protesting against any such dogmatic and
sweeping assertion being made or accepted in the present state of
our knowledge of the subject.
Opinions must not be represented as facts before they have
received: general acceptance. In a question in which the geological
world is undoubtedly divided in opinion, no such sweeping asser-
tions can be admitted as evidence in investigations of such intricate
nature as those which are the subject of the present inquiry.
Mr. James Geikie cites, in support of his views, the labours of
the late Professor Keilhau in his so-called “'Transition-formation
of Christiania,”* but surely, in so doing, he must be quite unaware
that these had long ago been most thoroughly disproved, and set
aside by the results of the subsequent explorations of Sir Roderick
Murchison,’ and the still later researches of Professor Kjerulf,* in
his work upon that formation, which I would here recommend to all
geologists as a model for the investigation of similar metamorphic
phenomena as are here referred to.
Notwithstanding my distinct statement to the contrary, Mr. James
Geikie seems determined to make the object of my communication
appear as a declaration against hydrothermal action, and will not
remember that it really was to examine his evidence, not to dispute
his conclusions; and I now maintain, whatever truth may or may not
1 Amongst others, I can refer to the highly crystalline Hornblende rocks so ex-
tensively occurring on the whole of the south coast of Norway, examined by me in
1853 and following year, and which it will be seen in my “ Geologiske Undersogelse
over det_metamorphiske Territorium, ved Norges Sydkyst.”” Nyt Magazin for Natur-
videnskaberne, Vol. iv. p. 164 et seq., I have declared to be, in my opinion, all
formed im sit% from tuffs of aqueous deposition.
2 Nyt Magazin for Naturvidenskaberne, Vol. i., 1838, and more fully in the Gaea .
Norwegica, Vol. i., of same author.
3 Quart. Journ. Geol. Soc., Vol. i. p. 467.
* Das Christiania Silurbecken chemisch geognostish untersucht, 1855.
Correspondence. 229
be in those conclusions, that they were not warranted by the evidence
which he has laid before the geological public, who will, I think,
agree with me in returning the Scotch verdict of ‘not proven,” and
advise him to try again if he wishes to convince the geological
world of their correctness.1
To avoid extending these remarks to too great a length, I will, in
conclusion, only refer to one more point in Mr. James Geikie’s
reply.
That gentleman differs from me as to the meaning of the term
“ oreywacké ” in petrology,? and in page 178 informs the readers of
your Magazine that “the greywackés familiar to Scottish geologists
do not ‘consist essentially of seventy-five per cent of quartz,’ nor
have they any definite composition whatever. The term ‘ greywacké,’
as used by Scottish geologists, is applied exclusively to the hardened
felspathic, and sometimes argillaceous sandstones of the Silurian
regions, in which, although quartz is frequently present, it is by no
means a necessarily preponderating ingredient.”
Always regarding science and its nomenclature as cosmopolitan,
I am of opinion that such style of argument should be protested
against; as no doubt Mr. James Geikie would do, if informed that
he must be quite wrong, because ‘‘ Manx” ® geologists entertained a
totally different opinion of the rock species “‘ greywacké.”
1 Since my former communication, the arrival of Dr. Sterry Hunt in this country
has procured me the pleasure of his personal acquaintance. The opportunity thus
afforded us, of comparing notes on chemical geology, showed how many similar con-
clusions we had respectively come to, from the study of widely different parts of the
globe, and assured us that any difference in opinion could not arise as to the agencies
employed in Nature's operations, although we might be somewhat at variance as to the
precise extent to which each agent had been engaged.
2 A study of the rock in the field in localities specially characteristic, combined with
an examination of the descriptions given by the numerous writers on the subject, has
resulted in my defining this rock species as follows :—
Greywacké.—A sedimentary rock usually of a greyish colour (whence its name)
found extensively developed in the earlier geological formations; but not specially
characteristic of anyone of same. Petrologically, ‘‘greywacké” is an impure sandstone,
more or less argillaceous, formed from the débris of previously existing rocks, re-
arranged by aqueous action, and subsequently, more or less eonsolidated. Usually
compact, it may vary in texture from fine-grained to coarsely conglomeritic; the
stratification of the beds is frequently indistinct, unless viewed upon the large scale ;
when coarse it may contain fragments of fossils, and of other rocks, as clay-slate,
mica schist, granite, porphyry, limestone, etc. Mineralogically, it is essentially
quartz, with more or less clay, and frequently contains grains or scales of mica,
chlorite, tale, lithomorge felspar, calcite, iron pyrites, etc. Chemically, it is composed
of some seventy to eighty-five per cent. silica, along with alumina and a little oxide
of iron, with but traces of the alkali and alkaline earths. Chemical and micro-
scopical examination show comparatively little combined silica, the major part being
in the free state as quartz.
This definition I maintain is in accordance with the views of all the writers on the
subject whom I have consulted, and in corroboration thereof, I would cite the follow-
ing references: Bischoff, iii. p. 132; Blum, p. 284; Brongniart, pp. 123, 126;
Coquand, p. 2388; Cotta, p. 301; D’Halloy, p.15; Erdman, p. 173; Grimm, p. 215;
Jameson, p. 226; Kjerulf, p. 72; Leonhardt, p. 171; Mayer, iii. p. 1; Maccul-
loch, p. 858; Page, p. 309; Pinkerton, i. p. 291; Phillips, p. 654; Roth, p. 59;
Senft, p. 332 ; Zirkel, ii. p. 594.
3 And our little Island is probably one of the best localities in Europe for the study
of this rock.
230 Correspondence.
I had, however, far too great a respect for the many eminent
geologists of Scotland, and too little confidence in either Mr. James
Geikie’s petrology, or his assertions, to accept the ahove statement
without examining into its correctness, and I think the result of the
inquiry will satisfy the public that the name of the Scottish geologists
has been taken in vain, and that
1. The term “greywacké,” when “familiar to,” and ‘used by”
Scottish geologists, corresponds satisfactorily with the definition
I have accorded to it—one endorsed by geologists of all nations.
2. That this rock possesses not only a distinct mineral character,
but, within certain limits, also a definite chemical composition.
3. That quartz is ‘“‘a necessarily preponderating ingredient,” and is
generally present in fully seventy-five per cent.
4, That the term is not, by Scottish geologists, “exclusively applied
to felspathic,” etc., nor that the word “felspathic’’ should be
at all used when referring to normal “‘ greywacké.”
Mr. James Geikie, who in his reply expresses his doubt as to my
“ careful examination of the literature of the subject,” will think it
still more strange and presumptuous in my thus attacking him at
home, and undertaking the defence of the Scottish geologists ; but I
. would ask him whether he is aware that it was a Scottish geologist,
_ Professor Jameson of Edinburgh, the pupil and friend of Werner,
who first introduced the term “ greywacké” into the English scien-
tific language; and if he will refer to that author’s work upon the
mineralogy of the Scottish Isles, published in 1800, he will there
find (vol. i. p. 226) my definition perfectly confirmed. If, then, he
turns to the (for its period, excellent) work on petrology, ‘“ Mac-
culloch’s Classification of Rocks,” published in 1821. also by a
Scottish geologist, it will be seen, at page 358, that the different
varieties of greywacké are there respectively defined as rocks
composed of—
1. “ Quartz sand, intermixed with lamina or massive schist.”
_ 2. “Quartz gravel, of various sizes, similarly intermixed.”
3. “ Argillaceous schist, with very fine grains or powder of quartz.
Not fissile ; fracture sometimes rough and splintery, and often
' resembling the fine and grey varieties of primary sandstone.”
_4. Ditto, “with visible grains of quartz of various sizes, and re-
sembling the coarser varieties of the same rock.”
And if, to carry the literature of the subject down to the present
day, he refers to a recent work, also Scottish, and which he already
has quoted in his reply, viz., Page’s Advanced Text-book of Geology,
he will there find (p. 309) the previous descriptions confirmed—
_ nor in any case will he find the felspathic element of greywacke,
which is so convenient for his metamorphic hypothesis, even alluded
to by these Scottish geologists. Davip Forsss.
Lonpon, 3rd April, 1867.
Correspondence. 231
THE DRIFT OF THE WESTERN AND EASTERN COUNTIES.
To the Editor of the Gnotocican MaGazIneE.
Srr,—I see that Mr. Hull has favoured you with a simple classifi-
cation of the drift deposits of Lancashire and Cheshire, which he
asserts to consist of (8) Upper Boulder-clay or Till, (2) Middle
Sand and Gravel, (1) Lower Boulder-clay or Till) Now some
twenty-five years since, in a, paper printed by the Manchester
Geological Society, I gave the following general classification :—
1.—Beds of stratified and-unstratified gravel and sand, containing
well rounded pebbles of primitive Primary and later Secondary
rocks.
2.—Till, a thick deposit of marl or brown clay, mixed with
angular or rounded pebbles of various sizes without any order of
deposition.
3.—Beds of stratified fine roiled gravel and forest sand, often con-
taining beds of clay or loam.
4.—Deposits of gravel and sand, both stratified and unstratified,
found in the beds of valleys and low lands adjoining rivers and
brook courses.
In addition to the above a bed of rich loam is frequently found in
the valleys, covering the last-named deposit.
The Till or Boulder-clay of Lancashire and Cheshire, as seen at
Blackpool and New Brighton on the coast, is one thick bed inter-
calated with beds of silt, sand, and gravel; but when we approach
the sides of the Pennine Chain, a very different series of beds
occurs. At Broadstairs Colliery, near Hyde, the following section
in the descending order was met with, viz. :—
FT. IN. FT, IN.
1a CLC ae a EAS 1k 0 8 Quicksand and Loam...... 6 0
Ae Quicksand',..2s2.cekesss.0ee 2 6 Di wiGEAV el wsctsecehackeekeeeoees 3 0
Ses econey Marl i... sees senss vs 22 6 | VON oat, CReccoc scene ates ances 7 6
4 Quicksand ..............0..0.08 206 11 Gravel and Sand............ 3 0
5 Loam with Pebbles ......... 12 6 12 Clay and Loam ............ 15 6
6 Buck-leaf Marl......... ..... 19 0 13 Gravel and Soft Marl con-
MDPDEN SANG Yoko ptinnshhtannay veh 9 0 taining Pebbles ......... 10
I give this section as an instance to show the difficulty of classify-
ing the drift deposits, either by my old arrangement or Mr. Hull’s
new one. At present, probably both must be considered as provi-
sional, to be perfected when the deposits have been more thoroughly
investigated and better known.
The eastern part of England, I imagine, is in about the same con-
dition; for, after some years examination of the Drift deposits in
Notts., Lincoln, York, Durham, and Northumberland, I have not
been able to make the sequence of the beds, as Mr. S. V. Wood, jun.,
appears to have found, more to the south.
I remain, Sir, yours truly,
E. W. Bryvevy.
Mancuester, April 8, 1867.
232 Correspondence.
FISH IN THE OLD RED SANDSTONE.
To the Editor of the Grotoctcan MaGazine.
Srr.—Mr. Pengelly’s answer is clear and definite. Such good
authorities on fish remains give one the strongest reason to believe
that this Upper Old Red fish really does occur in what we believe to
be Lower Devonian. .
On the Irishman’s principle of coming for aid to-day, because he
was relieved yesterday, I must ask three or four more questions.
First, is it sure that the locality, Meadsfoot Bay, is the same age as
the ‘Meadsfoot Sands, which are certainly Lower Devonian, by their
fossils. The country is awfully faulted ; and as the Barnstaple beds
(Upper Old Red, as I have proved by their fossils) are everywhere
likely to be unconformable, on the Middle and Lower beds, I think
it is possible we may get patches of it here and there, and should
like to know (it is years since I saw Meadsfoot) if the beds can be
continuously traced.
Next, I should like to ask whether Plewrodictywm problematicum
Goldf., one of the most characteristic of the Lower Devonian corals
in 8. Devon, and in the Rhine country, really ever does occur in the
Barnstaple group, or the Coomhola grits of the south of Ireland?
It has been frequently quoted of late years (I believe by Professor
Jukes). Will my friend Mr. Baily re-examine his specimens; and
any others who may possess this fossil make sure of it?
There is a Dictyophyllia, a Lower Carboniferous coral, allied to
Pleurodictywm, common enough at Barnstaple, but not, I think, the
same species as the Mountain Limestone fossil. This I have seen
from various localities in the Uppermost Devonian. Is it possible
that it may have been mistaken for the Pleurodictyum ?
Again, has any one ever seen, in Mountain Limestone rocks,
Stringocephalus, Calceola, Pentamerus, Atrypa, Uncites, Strophalosia,
the various species of Acervularia, Cystiphyllum, Smithia (or Strept-
astrea), Heliolites; the forms of Favosites, allied to F. cristata and
F. cervicornis, the Devonian types of Hexacrinus, Spherocrinus,
Stylocrinus (Cupressocrinus is rarely found, I know, in Carboniferous
Limestone, but is characteristically Devonian for all that), the elon-
gated forms of Pentremites, Phacops, Pretus, Harpes, Cyphaspis,
Homalonotus, Bronteus, Cheirurus, ete.
If none, or next to none, of these genera occur in Mountain Lime-
stone localities: if Productus is everywhere common in the last, and
absent in the first: and if the corals, crinoids, shells, trilobites,
and fish, which characterize the Devonian, are absent in the overlying
Carboniferous—and vice versa, what is the use of trying to make the
one the equivalent in time of the other ? Yours truly,
J. W. SALTER.
P.S.—Since I wrote the above, Mr. Pengelly has brought up his
specimens to London. The Phyllolepis from Meadsfoot is indeed like
that genus. The fish-defences (Ctenacanthus ?) are equally unquestion-
able ; they are from Looe Island. There is nothing like asking ques-
tions to get at truth. Here have been some valuable data long buried ;
Correspondence. 233
and now my friend consents to have them figured and described by
our best authorities. So I must invite geologists, if not Mr. Pengelly
himself, to find for us what shells, corals, etc., occur with these
actual specimens. They do indeed appear to lie in the lowest beds ;
but there is the possibility, I have above hinted at, of the Upper
beds overlapping unconformably round the south coast, where
hitherto we have not known them. Near Teignmouth, indeed, we
have the Upper Devonian beds; and my note-book tells me there is
a fault (one out of many in this district) between the Meadsfoot
sandstones with Lower Devonian shells, and the pile of grey rocks
which hold this fish-scale ; and unconformity and faults will do any-
thing but mix the fossils in the bed itself, especially in 8. Devon.
But Looe Island with the fish, is not Looe with its Lower Devonian
shells; and Meadsfoot fish-bed has not yet been proved to be the
same beds as those which hold the trilobites and shells. Here is
work for the local geologist; and as asking about the fish has pro-
duced so much, I hope asking about the geology will do more. We
want now to know what are the exact relations of the beds which
hold these fish: for fish they are—the only ones (the N. Devon one
was a mistake) known in British Devonian rocks.—J. W. 8.
BALA AND HIRNANT LIMESTONE.
To the Editor of the Grotocican Macazinn.
Str,—There is a point of much interest to be worked out in North
Wales: viz., the exact relation and age of the upper or Hirnant
limestone of Bala.
Some of the fossils in this remarkable band are known. It is
the only example (so far as I know), in rocks below the Wenlock
limestone, of a pisolitic structure ; very marked in the neighbour-
hood of Bala. But beyond Bala, etc., it is not at present known.
I beg to suggest an excellent piece of work for one of the Clubs
this year (unless Mr. Davies, of Oswestry, means to do it single
handed). It is to work out thoroughly the geology of one mountain,
close to Llangollen, and therefore easily accessible. If they would
examine Mynydd-Fron-Frys, which is not a lofty one, and has good
roads all round, it will be much better service than making what is
called a section or a traverse. There are two beds of limestone
there :—the Bala limestone, and an upper one, probably, the
“‘Hirnant” limestone; and from this locality some of the very
rarest of our Bala fossils have been obtained.
There is a huge Loxonema there, six or seven inches long; a fine
Lituites, viz., L. anguiformis,—the only specimen known in Britain,
yet, is that in the Woodwardian Museum. Then, again, there is a
species, probably new, of Bumastus to be found; and such a crowd
of Corals, Bryozoa, and other choice things, that it is like working in
a museum ; I had but two hours for it all.
Now what we want to know is the exact contents of each of these
bands of limestone; for one is probably very different from the
other. And if the above rare fossils are from quarries in the upper
234 Correspondence.
bed, no wonder we do not know them elsewhere in the great Bala (or
Caradoc) series. Besides that, in all probability, the north end of
the hill is made up of the Llandovery rocks. I will gage almost
anything I have (and that is not much), that the Llandovery con-
glomerates and shales occupy the hill of Pentre, and the slopes
above Tal-y-Garth. Beyond this I will not suggest, for the neigh-
bouring ground looks terribly faulted; and no one knows what is
the actual base of the Upper Silurian series in the valley,—seeing
that the pale “‘Tarannon” shales are not traced there, nor are the
Denbighshire grits: indeed the latter never were there at all.
I know no place within easy reach, (for that is something in the
matter,) where a Club-meeting might do more good; but then they
must make up their minds to walk the hill across from north to south,
and m several directions ; and not disperse their energies over a long
section, or go in search of the picturesque. The geology is very
simple in the hill itself; but outside of it, faults and unconformable
junctions obscure everything.
1. Slates under the lower limestone.
2. Lower limestone (Bala). nt)
3. Slates between the limestones (Upper Bala).
4, Hirnant limestone ?
5. Soft slates—which may be Llandovery ?
6. Llandovery conglomerates ?
Will anybody set to work on it ? J. W. Sarrer.
GENERAL GLACIATION OF IRELAND.
(WITH A MAP.)
To the Editor of the GroLocicaL MaAGazine.
Sir,—A number of copies of the accompanying map having been
cast adrift by the unforeseen discontinuation of the Dublin Quarterly
Journal of Science, for which they had been prepared, you have
charitably consented to afford them harbour in the GuotoeicaL
Magazine. At your desire I give an explanation of the map, and a
concise account of the paper which it illustrates (noticed by yourself
in your April number, and to be contained in the forthcoming part
of the Journal of the Royal Geological Society of Ireland). The
facts have been derived from a variety of sources, including my own
observation.
The black strokes give the direction of the parallel ridging, which
is so well developed over much of the low ground in this country.
The ridges usually consist of Boulder-clay with well scratched and
blunted (not rolled) stones; but sometimes the parallel shaping
seems to be partially wrought in the rock. The Boulder-clay ridges
are totally distinct from Eskers (or Kames) ; their average length is
about three quarters of a mile; they sometimes exceed one hundred
feet in height. The red strokes represent parallel rock-scorings.
When the scorings show clearly, of themselves, which way the
grinding agent went along the line of its motion, the strokes repre-
senting them are made into arrows. Cross striations, later than the
+
VOL Vil. PLATE 1.
| “MAP
“ Geveral Glaciation
= of
ee
ON
IRELA®D.
B Ss
Gamay xe
See
UA
Strike of ridges
Rock-scorurg s.
Directeory of Drift carriage
Four mates NE. Carrick on Shannon
Loughzee lown R. Roscrea M. Lough Maxk
. Rarige of Ox M® Sligo
Range ot Sieve Bloom, Devits Bri
and Keeper M* taterrupted at R.
sata tar
ye
td
Correspondence. 235
principal ones, are omitted; as also are the traces of the strictly
local glaciation among the mountains. The dotted arrows indicate
the direction of the drift transportation; im most cases, certainly,
and in the rest most probably, it is the movement of the Boulder-
clay which is given. Since the three kinds of phenomena always
agree so remarkably as to direction, they must be effects of a common
cause; and, therefore, they may be used jointly or separately, as
opportunity occurs, in tracking the courses of the streams by which
they have been produced.
Those streams must have consisted of glacier ice; because various
considerations shew that no other agent is capable of doing everything
that has been done, and of moving as the streams have moved. The
universal glacier was, probably, not less than 38,000 feet in depth.
It was, at its greatest development, but little dependent on the
mountains, as sources of supply ; it was sometimes inconvenienced by
them as obstructions to its movement. Its tendency was to spread
outwards in every direction, without much regard to the general slopes
of the open ground. Asa result of its great depth and magnitude,
its mobility must have been vastly greater than might be sup-
posed possible on first thoughts, and sufficient to enable its different
flows to move as shewn on the map. Those flows formed a con-
nected, though not single, system—their mutual interference has
sometimes affected their movements quite as muchas the resistance of
the masses of elevated ground. Thus, the stream which flowed south-
ward, near Carrick-on-Shannon (c), has divided, without having
been compelled to do so by anything in the shape of ground there-
abouts. The right branch of that stream has turned sharply away
from the wide plain before it, and flowed directly towards, and then
across, the (not very elevated) range of the Ox mountains, Sligo
(xx). The stream, which flowed eastward from near Loughrea (1),
has behaved in a somewhat similar manner. There were, however,
radiating district ice-systems, belonging to some of the mountain
groups; of which the most remarkable was that of Kerry and W.
Cork. These may have existed during the height of the glacial
development, or they may not have been established until afterwards.
They were older than the submergence in the glacial sea; and older
still than the local corry glaciers, of which we have evidence in so
many places. To explain fully the movements of the flows of the
general ice-envelope, it seems necessary to suppose that the west side
of Ireland was formerly higher, relatively to the east, than it now is.
Some independent considerations confirm this supposition. It is
most probable that the ground near the head of what is now Galway
Bay occupied a somewhat central inland position during the period
of the general glaciation.—Faithfully yours, M. H. Cross.
Newtown Par, Brack Rock,
Dousuin, April 9th, 1867.
236 Correspondence.
MR. TOPLEY ON ESCARPMENTS.
To the Editor of the GrotocicaL MAGAzIne.
Drak Sirr,—I should not have troubled you with another letter,
were it not that Mr. Topley, in your last, unintentionally misre-
presents my views so as to make them appear inconsistent. In reply,
I shall endeavour to be as brief as possible.
Revival of Old Theories.—Mr. Topley regards with disrespect the
act of a geologist going back to old times for an explanation of phe-
nomena, as if conformity to prevailing fashion in a science were
more philosophical than a simple desire for truth. In the history of
geology, old fashions have often been revived. The glacial theory of
the Parallel Roads of Glenroy was framed by Agassiz in 1840, during
his Highland tour with Dr. and Mrs. Buckland. It was displaced
by the marine theory, which lasted until 1863, when the glacial theory,
as explained by Jamieson, received the sanction of the Geological
Society. Mr. Topley himself, in his rain theory, has gone back to
the days of Hutton and Playfair. The theory of “ waves of trans-
lation ” has found favour with eminent geologists within the last few
years, and is still held by Sir Roderick I. Murchison. I do not think
Sir Charles Lyell would object to a wave of translation, such as might
be caused by an earthquake capable of upheaving a sea-beach to a
height of 40 or 50 feet, or that he would assent to the extreme form
in which Mr. Topley has stated his protest against “large bodies of
water.”
Lyell on Marine Currents.—I never regarded waves as more im-
portant denuding agents than currents, and Sir Charles Lyell, so far
from disclaiming the latter, lays the main stress on them. He says
(if I rightly remember his words) ‘‘ the chief influence of the ocean
is exerted at moderate depths below the surface, on all those areas
which are slowly rising, or are attempting, as it were, to rise above
the sea.” Currents may have formed the extensive escarpments and
terraces revealed by soundings in the Atlantic Ocean, and currents
may have commenced those long lines of subaérial escarpment which
are rarely paralleled on modern sea-coasts; but most of the escarp-
ments with which I am acquainted show traces of having been at least
modified by coast-action. Assuming their littoral origin, England
would not be a likely area to present fac-similes of them at the
present sea level. Such can only be expected on coasts where the
sea is “deep to; where it is not prevented, by the task of silting up
shallows, from following the strike; and where, beneath the line of
cliff and the influence of waves, there must be a sloping submarine
talus of angular materials, similar to that forming the lower part of
many inland escarpments.
So-called Strike Escarpments.—The mode of action assigned by
subaérialists to rain and frost involves an entire dependence on
structure. Rain and frost can only originate and carry on the work
of denudation in conformity to the strike; but on minute inspection
it will be seen that many parts of so-called strike escarpments show
a dip along the face of the cliff which proves that the denudation
Correspondence. 237
in these parts must have proceeded obliquely to the strike. In those
escarpments which consist of a succession of headlands, bays, and
combes, a very considerable part actually runs unconformably to the
strike ; in other words, the bedding is oblique to the planes of marine
denudation either above or below the escarpment (instances—the
great Cotswold escarpment, the Eglwyseg line of cliffs near Llan-
gollen, etc.). With regard to Mr. Topley’s statement that the line
of cliff now in course of being formed by the sea in N.E. Yorkshire
is unparalleled by any inland escarpment, I think reasons might be
assigned why a perfect parallelism should not be found in Britain.
It is not true, however, that all the escarpments of this country ex-
hibit a continuation of the same beds. 'The Lias escarpment N.E. of
Taunton may be regarded as a continuation of the Greensand escarp-
ment to the south. The escarpment extending from Uphill, near
Weston-super-mare, towards the H. and N.E., embraces, in hori-
zontal succession, a repetition of limestone, Trias, Lias, and, if I
remember right, Permian conglomerate.
Short Lines of Obliquely-stratified Ciifis—These may be met with
almost everywhere in the Lake district, and in many parts of Wales,
Somerset, etc. (Instances—some of the cliffs of Cader Idris ;
several cliffs on the S.E. side of the railway, between Penmaen Pool
and Barmouth Ferry Station ; cliffs in the upper valley of the Wye,
at high levels above the river: the cliff behind Clevedon ; many
cliffs at high levels on the Mendip Hills, especially between Shute-
shelf and Longbottom Passes, and on one side of the latter; parts of
the celebrated Cheddar Cliffs, etc.).
Strike following Sea-coasts—Among the instances in which the
sea shows a tendency to follow the strike, may be mentioned the
cliffs to the south of Clevedon, in Somersetshire. On the sides of
Brean Down, near Weston-super-mare, the sea pays about equal
regard to dip and strike. On many parts of the west coast of Wales
the sea shows a preference for the strike. A whole article, detailin
instances in other places, might be written. It is still true, that the
sea pays comparatively little “regard to dip and strike,” and equally
true that dip and strike solely determine the direction of the denuda-
tion effected by rain and frost.
Synclinal Hills—Though to Mr. Topley it may be sufficiently
clear, I cannot understand how a hill, consisting of a perfect synclinal
basin with the strata dipping inward on all sides (in the same para-
graph, in speaking of the same hills, Mr. Topley uses the term most
sides) can show a dip in any part of the face of the surroundin
escarpment, as they do in Eston Nab and Upleatham Hill. [|
venture to believe that the strata of many of the so-called synclinal
hills dip towards each other only from two points of the compass, in
which cases they do not form basins, but synclinal axes. Jt ig
certain that some of these hills have this structure, and that the
denudation by which they have been left, has followed the strike on
two sides only. In their case the atmospheric theory furnishes no
more than half an explanation. They can be fully accounted for by
1 Topley, Grou. Mac. Vol. III. (Oct. 1866), p. 438.
238 Correspondence.
the sea, which shows a versatility not possessed by subaérial agents,
and which can breach through and overcome almost any exception
to its main mode of action. Many detached hills near escarpments
appear to be decapitated headlands, and can be at once explained by
the well-known tendency in the sea to enlarge bays laterally, until
connecting passages are formed. D. Macxinrosx.
TEIGNMOUTH.
P.S.—As the work of excavation for villas proceeds, the proofs of
the marine denudation of the hills and valleys of the Torbay district
assume a more and more demonstrative character. On this subject
you will soon hear from me again.
GRAPTOLITES.
To the Editor of the GkotocicaL Macazinz.
Sir,—I am sorry to have again to beg for a portion of your space,
but I am unwilling to let pass, without brief comment, certain state-
ments advanced by Mr. W. Carruthers in his letter on Graptolites
in your last number (page 187).
I do not find it necessary to enter here into any further discussion,
as to the nature, or connexions, of what I consider to be the ovarian
capsules of the Graptolites. I am now in the possession of a large
number of specimens, proving, as I think, conclusively, that there
is, in some species, an actual organic connexion, and I trust shortly
to publish the results of my investigations on this point.
As to the error, whereby Mr. Carruthers inserted the name of D.
Whitfieldii for that of D. marcidus, I should be inclined to think that
this change does not much improve his position, as D. marcidus
does not seem to agree with D. tricornis in anything except the
common character of possessing three processes at the base.
Mr. Carruthers appears not to be fully acquainted with the true
nature of a “‘radicle,” as defined by Hall, or, I think, he would not
assert that D. Whitfieldii is provided with more than one. The two ~
lateral spines, to which he alludes, are found in D. pristis, and in
various other species, and are simply processes from the first two
cellules on each side, and not “radicles ” in any sense of the term.
My statement, that D. tricormis possesses three “ mucronate” radicles,
was simply made in deference to Mr. Carruthers’s figure of this
Graptolite, where the nature of the lateral spines cannot be made
out; and, also, on the supposition that he would not have chosen a
specific name expressive of a character common to several species.
Mr. Carruthers still seems to think that the cellules in D. pristis,
of Hisinger, are mucronate. My assertion to the contrary, if wrong, .
is at any rate supported by all the descriptions of this species to
which I am able to refer. In neither the figures nor descriptions of
Salter, Hall, M‘Coy, Harkness, or Geinitz, is there any mention of
anything of the nature of spines to the cellules of D. pristis. As
Mr. Carruthers has simply repeated his statement, and has not seen’
fit to bring forward any proofs of its accuracy, he must permit me in
Correspondence. 239
the meantime to adhere to the opinion I formerly expressed ; since
I am constrained to believe that the above-mentioned paleeontologists
must have had opportunities of studying this Graptolite as good as
those enjoyed by Mr. Carruthers.
Finally, I am sorry that anything I have said should have led
Mr. Carruthers to the belief that I wished in any way to dogmatize
as to there being a connexion between the capsules and the Grapto-
lites; and I should have thought I had stated with sufficient plain-
ness that I considered that my views were as yet conjectural, and
that Mr. Carruthers’ opinions might “ultimately be proved to be
correct.” J am likewise sorry that I should need to recal to Mr.
Carruthers’ recollection, that the existence of capsules, ‘“ vertically
compressed,” does not rest simply upon my “‘ipse dixit;” but that
Professor Harkness had seen my specimens, and had come to the
same conclusions about them asI had. Jam, Sir, etc.,
H. AtLEYNE NICHOLSON.
Epingureu, April 13¢h, 1867.
A WAVE OF VOLCANIC DISTURBANCE IN THE MEDITERRANEAN.
To the Editor of the GkotocicaL Macazine.
Srr,—The accounts of Harthquakes, Volcanic Eruptions, etc.,
which have reached us from the Mediterranean coasts and islands,
during the latter part of the past, and the earlier part of the present
year, have been so numerous that they lead me to suspect that they
are attributable to one common origin, and are the result of a
plutonic agent which convulses the whole Mediterranean.
These disturbances seem to date from the eruption of the islands
at Santorino last year. Professor D. T. Ansted was the first to
point out the connection of this phenomenon with the eruptions of
petroleum, which soon after took place at the sides of Mount Htna.
Again, M. Mauget recently sent a paper to the Paris Academy of
Sciences, stating that last July the wells and springs of Naples
and the neighbourhood suddenly diminished their supply; whilst,
by the injection of carbonic acid from the fissures diverging from
Mount Vesuvius, the fish were poisoned. This year the earthquake
at Algiers has been succeeded by the eruption of a “geyser ;” i.e. a
column of steam, fifteen or twenty yards high, has burst forth from
an aperture three feet in diameter, near the sources of the Ain-Bada.
Earthquakes at Cephalonia and Malta I mentioned in my last letter.
A more fearful shock, killing thousands of persons, and submerging
great part of the land, has been telt at Mytelene, on March 6th.
This earthquake was even experienced as far as Constantinople and
Smyrna. A volcanic eruption has occurred very lately at Pantellaria,
between Sicily and Africa. Recent telegrams announce an earth-
quake at Naples. The ship ‘“ Sidon” announced that on March 7th,
being seven miles off Mytilene, they experienced two shocks of a
submarine earthquake.
Now does it not seem that all these phenomena point to a great
wave of volcanic agency disturbing the Mediterranean, its coasts,
240 Miscellaneous.
and its islands? It is said that nine proofs are sufficient to sub-
stantiate a case, and as we have fully that number, I think we may
safely credit the theory. The difficulty is perhaps to find the centre
of the disturbance. An eye-witness of the earthquake at Algiers
supposes the centre of that shock to be in the Atlas Range; but as
that would be too distant to affect the whole Mediterranean, I think
it is more likely to be between the volcanoes of Htna and Vesuvius.
Yours, etc.,
Tue Crescent, SALFORD, L. C. CasaRtEnyt.
April 10th, 1867.
MIiSCHBLEANBHOUS.
—————
RemarKAaBLe Harp Form or Awnrturacitt.—M. Dumas has
called attention, in the Comptes Rendus, to some nodules of
anthracite, remarkable for their hardness, which were placed at
his disposal by the Count Douhet; who found them at a dealer’s,
and secured them for scientific investigation. 'These nodules have
apparently a concretionary structure, and are hard enough to
scratch glass, and even harder bodies, with ease. Leaving out
the ash, the composition is found to be :—carbon 97-6, hydrogen
0-7, oxygen 1:7, which agrees with the composition of anthracite.
Its density is 1:66. With the opacity, density, and composition of
anthracite, these nodules possess the hardness and take the polish of
the diamond. M. Dumas was not the first to notice this interesting
form of carbon. Several years ago M. Meéne experimented on some
anthracite from Creuzot, Dept. Sadne-Loire, France. When this
coal was raised to a high temperature in a muffle, it was converted
into a friable steel-grey mass, in appearance somewhat metallic.
When this high temperature was continued about two hours, the
fragments in the crucible were nearly always sufficiently hard to
scratch glass and steel with the peculiar sound of the diamond. The
composition of this substance was found to be :—volatile substances
1:0, carbon 96°8, ash 2:2; and its density 1-637. At first M. Méne
could not procure this hard form of carbon from the anthracites of
Valbonnais in ,Savoy, and Abercraf in South Wales; but by con-
tinuing the high temperature for four hours he obtained similar results
to the previous experiments. Some pieces of coke, prepared from
ordinary bituminous coal, mixed with anthracite, with a view to the
utilisation of the latter for blast furnaces, presented numerous
brilliant points, which scatched glass. The endeavour to apply this
carbon in a powdered state to the polishing of metals like steel was
unsuccessful, as the powder always scratched the metal. It is to be
hoped these important researches may be continued, the “ Société
d’Encouragement” having offered a prize for chemical investigations
on the production of carbon analogous to the black diamond.—
Comptes Rendus. PD.
GEOLOGICAL MAGAZINE.
No. XXXVI.—JUNE, 1867.
ORLGINAL ARTICLES.
SS
I.—On tue DISTRIBUTION BEYOND THE TERTIARY DISTRICTS OF
Wuitr CLAYS AND’ SANDS SUBJACENT TO THE BoULDER-CLAY
Drirts.
By Grorct Maw, F.G.S., ere.
(Parr I.)
HE object of the following paper is to record some further ob-
servations on the distribution in North Wales of deposits of
White Clays and Sands older than the Boulder-clay and its accom-
panying gravel drifts, similar to those in the neighbourhood of Llan-
dudno, described in the GroLocicat Macazine of May, 1865, and also
to give a condensed summary of what records I have been able to
collect of the occurrence of similar deposits in other parts of the
kingdom.
The well-defined and compact geographical disposition of the re-
cognized Tertiary deposits of Great Britain renders the occurrence
of beds of similar physical character inferior to the Boulder-clay, in
outlying districts, a matter of no little interest, and with a view to a
more exact comparison of these deposits in different parts of the
kingdom with each other and with their possible analogues in the
Tertiary districts, I have endeavoured to bring together in a con-
densed form all that has been hitherto observed of these singular
formations.
North Wales.—Since publishing in the Grotocican Macazine of
May, 1865, a description of the Clay- and Sand-Pockets near Llan-
dudno, I have learned from Mr. Binney that he made some obser-
vations on them several years ago, and published a-short account in
the Transactions of the Manchester Geological Society, but I have
not yet seen his Memoir.
The only other locality in Carnarvonshire where I have observed
similar deposits, is at a place called Werndow at the back of Conway
Mountain, about a mile and a half from Conway, where white clay
and sand are visible in several of the ditches. Some pits were
opened a few months ago with the object of working the clay for
pottery purposes, but there were no sections exposed at the time
of my visit. The fundamental rock is here Lower Silurian, and it is
the only instance that has come under my observation of these de-
posits occurring off the Mountain Limestone.
VOL. I1V.—NO, XXXVI. 16
242 Maw—Distribution of White Clays and Sands,
Fig. 1. Sand and clay pocket, about 180 feet in diameter, in Mountain Limestone,
near Longrake Mine, Halkin Mountain, Flintshire.
.
x
S . Qe ee
ee KS fi Buenne ces ieee ae er
Soe A SUNG Bac ea nae a sleet ina os Ob teeter A
————ee NES -- f
x eyes Doe oR mace Pa ot
aS Ra x caer lites.
a range ee ee | ye bE Sides ALT? < :
pee ine: So evan wvevend ua ——-. +
ee, —_——___ = SS RX ~ ips ch at 2 a
ae Sera Wiese een Cane) ea —-
A. Drift. 06. Dark laminated clay. c. Tenacious light-coloured pipe-clay, interstratified with
white and black sands with occasional layers of soot-like carbonaceous matter.
Passing to the eastward, several pockets containing white clays
and sands occur in the Mountain Limestone of Halkin Mountain and
the range of hills to the south of Holywell in Flintshire, sections of
two of which are given in Figs. 1, 2, and 3.
Fig. 2. Sand and clay pit, Bwlch Farm, near Nannerch, Flintshire.
A. Surface soil. 8. Drift. c. Dark clay with much carbonaceous matter. 4, Thin bed of
small white pebbles. e. Thin layers of tough white pipe-ciay. jf. Dark sand coloured with
carbonaceous matter interstratified with white and buff sands forming the bulk of the deposit.
No. 1 occurs about half a mile to the east of Longrake Mine at an
altitude of about 900 feet above the sea. The cavity appears to be
about 150 feet in diameter judging from the position of the surrounding
limestone on the surface, though the walls are not visible. The
superficial drift, now nearly all removed in working the sand, must
have been from 20 to 30 feet thick, under which the contents of
Subjacent to the Boulder-clay. . 243
Fig. 3. Supposed general arrangement of Pocket, containing sand and clay in
Mountain Limestone, Bwlch Farm, near Nannerch, Flintshire.
A. and B. Surface soil and drift. c. White sand interstratified with grey buff and black sand
and thin layers of tough pipe clay. bp. Mountain Limestone.
the pocket consist of stratified white, black, grey, and variegated
sands containing’ carbonaceous particles, also a layer about a.
foot thick of soot-like carbonaceous matter, and strata of dark grey
laminated clays, and nearly white pipe clay: the contents of this
pocket being but partially exposed, it is not easy to make out their
general arrangement; in places they are very unconformable, per-.
fectly horizontal sand beds terminating abruptly against almost ver-
tical strata of tough plastic clay, and in another place a little pouch
of level layers of sand lies in the midst of similar beds very much
inclined. JI have endeavoured to represent the arrangement in
Fig 1. The great variety of gradual shiftings and slippings, which
the contents of this singular cavity appear to have undergone, have
produced a complexity of arrangement not easy to explain.
The section represented in Figs. 2 and 3, occurs at a height of
about 850 feet above the sea on Bwlch Farm, between Nannerch
and Longrake Mine, one mile to the south-west of the example just
described. Fig. 2 represents in detail the portion actually ex-
posed, and Fig. 3 what is most probably the general arrangement
of the beds in the limestone cavity. The limestone is not visible
in immediate contact with the sand; but as the sand and clay has
been sunk through forty feet, and the limestone appears within a
short distance on all sides, they must occupy a complete ‘‘ Pocket,”
similar to those near Llandudno. ‘The individual strata in this
section quickly alternate, and are very thin, consisting of quite
white, grey, yellow, and black sands, separated by layers of tough
white clay, very regular and continuous, but not more than two or
three inches thick.
The darker beds of sand and clay contain a great deal of car-
bonaceous matter, and here and there, in contact with the clay-beds,
244 Maw—Distribution of White Clays and Sands,
are layers of very black carbonaceous earth. Some of the white
sand-beds contain thin layers of small white pebbles, about the size of
a pea, which appear to have been derived from the Millstone Grit :
on the west side of the section the strata are nearly level, but at a
very short distance to the east, they dip at a high angle.
There is a curious arrangement towards the bottom of the Sand-
pit, in which the overlying inclined beds are cut off suddenly against
some more level strata under them ; the whole of the strata are also
full of slight dislocations, faults, and slips, which irregularities
appear to have been produced by restricted movements within a
small area, and are disposed as though the beds had been gradually
lowered after their deposition into the Limestone cavity during its
slow excavation.
At Craig Vraddoc, between Bwlch Farm and Nannerch, on the
southern margin of the Mountain Limestone range of Flintshire,
similar sand is also found of a character different from that of the
Glacial drift of the neighbourhood, but I had not an opportunity of
examining the locality, or ascertaining the position of the beds.
Two or three cavities in the Mountain Limestone have been partly
emptied of sand and clay at Ty Coe, near Fridd Garreg Wen, 12
miles due north of Caerwys. One that has been abandoned for
some time appears to be about 150 feet in diameter ; I was informed
that it contained, with the sand-beds, a considerable proportion of
white clays, which were sufficiently tough for the manufacture of
tobacco pipes. I also observed a small exposure of dark laminated
clay strata near the circumference of the pocket, dipping at a steep
angle towards its centre.
A little to the south-east of Langynhafal, in the vale of Clwyd,
an adit driven for the purpose of working Hematite, exposed a
deposit of dark laminated clay, filling up a fissure in the Mountain
Limestone, of the same character as the clays on Holywell and
Halkin Mountains, and in mineral aspect closely resembling some of
the Eocene Clays of Dorsetshire, and the Miocene beds of Bovey
Tracey, in Devonshire.
Another example in North Wales, of which I have obtained a
section (Fig. 4) occurs at Pant du, near Llanferris, Denbighshire,
five miles to the south-west of Mold, at an altitude of about 900
feet above the sea. It appears to be a lodgment that has been
protected from denudation in the angle of a sort of amphitheatre of
Mountain Limestone rocks, one side being open to the main valley.
The clay has been worked for pottery purposes from a shaft sunk
into it seventy-five feet deep. The upper five feet is through lime-
stone débris and drift, succeeded by a mass of tough white clay, the
base of which was not reached, and consequently the position of the
fundamental limestone is uncertain. A head driven from the bottom
of the shaft towards the Mountain Limestone escarpment, intersected
horizontally 21 feet of white clay, 84 feet of soft chert breccia,
similar to that on the Great Ormes Head (described in GuonocicaL
Macazrne for May, 1865), and 27 feet of black laminated Clay, the
limit of which was not reached. All these beds dipped ata high
Subjacent to the Boulder-clay. 245
angle towards the north, and from the general lie of the ground and
the position of the Limestone rock to the south and north of the pit,
appeared to occupy a large pocket as represented in the accompanying
diagram.
Fig. 4. Clay Pocket, Pant du, near Llanferris.
A. Drift and Limestone Débris. 3. White Clay. c. Breccia of Decomposed Chert.
p. Dark Laminated Clay. x. Mountain Limestone.
The bed p closely resembles the dark clay at Llangynhafal and
Fridd Garreg Wen, and appears to occupy the same position in rela-
tion to the pocket and its contents, as in the latter locality.
At Maes y Safon Mine; about one mile and a half to the north
of Pant du, a similar bed: of white clay was found in digging the
foundation for a windlass, but the depth and extent was not
ascertained.
I am informed by Captain Cooke, of Colomendy Hall, that about
a mile further to the north, near his house, a shaft was sunk many
years ago, and said to have penetrated white clay for more than forty
yards without reaching the limestone; but exact particulars are
wanting. The probable existence of the clay is rendered evident by
a sinking of the ground, below the general level, on all sides—a
phenomenon almost invariably accompanying these deposits. A
shallow pit sunk on the spot a few years since proved the existence
of the clay on the surface, though the full depth was not ascertained.
Similar white clay has been found in sinking mine shafts in
several localities near Mold, in each case, as far as could be as-
certained, resting on the limestone under a considerable thickness
of Boulder-drift and limestone débris, and generally at a height of
from 800 to 1000 feet above the sea. Ata pit a little to the west of
Trinity Church, three miles to the west of Mold, under 93 feet of
drift and loose limestone boulders, 45 feet of white clay similar to
that at Pant du, was penetrated; and at Vron Hall Mine, at a depth
of 140 feet, a layer of white clay was found under the limestone debris.
246 Maw—Distribution of White Clays and Sands,
All the examples of these white clays and sands in North Wales,
though varying much in the relative proportion of sands and clays,
bear an unmistakeable affinity in mineral character. To the west,
in the neighbourhood of Llandudno, sand strata predominate with
but slight traces of clays. In the neighbourhood of Holywell the
proportion of argillaceous strata is larger, though the sand beds are
still in the ascendancy, and in the most easterly examples about Mold
the sand strata are almost absent, and replaced with considerable
asi of white clays, with occasional layers of dark laminated
clays.
Derbyshire and North Staffordshire-—For the followings facts I am
indebted to Mr. E. W. Binney, F.R.S., of Manchester, and Mr. E. Brown,
F.G.8., of Burton-on-Trent. Mr. Binney has placed at my disposal
his notes of several years’ observations on the distribution of white
clays and sands, similar to those in North Wales—over the Mountain
Limestone district of Derbyshire and North Staffordshire; and Mr.
Brown permits me to print a portion of his paper “On the Drifts of
the Weaver Hills,” read before the British Association at Notting-
ham—the result of independent observations in the same district ;
ae has obligingly supplied me with the section of the Weaver Hills
(Fig. 6).
Mr. Binney observes: “In a good many of the mines and fissures
of the Mountain Limestone of Derbyshire, elay, sand, and gravel are
found ; at Bolsover and Lindric common, near Worksop, beds of
clay of a light colour occur on the top of the Magnesian Limestone,
but they contain no sand or gravel.”
The earliest notice of the white clays, in the Mountain Limestone
district of Derbyshire, appears to be in Farey’s “‘General View of the
Agriculture and Minerals in Derbyshire,” published in 1811. In Vol.i.,
page 249, he says: “ Faults, as before observed, range along and have
broken the vein stuff and rake and pipe veins, and introduced rounded
Quartz pebbles, gravel and alluvial clay, and other extraneous mineral
matters below the Tick holes, which connect with the surface, and
such are often called soft veins or are said to be filled with ‘softs.’”’
These ‘Tick holes,’ connected with the surface, would appear to
be analogous with the “Pot holes” or Pockets of the Mountain
Limestone district of North Wales. Farey gives a list of mines in
which, what he terms “ Alluvial clay and other extraneous matter ”
derived from the surface have been met with; but in many cases
it is difficult to distinguish whether the white clays and sands
‘resting on, and contained by pockets in the limestone, are referred
to. The following mines taken from his list appear to be the
localities of the white clays, sands or gravels underlying the Glacial
drift :—
“Bald Mare,” in Brassington, is given as the locality of China
clay and gravel.
“‘ Bonds Vein,” North-West of Wirksworth ; in 8rd Lime—gravel.
“ Clay-pit Dale,’ near Hartmgton—China clay, and gravel.
“Dale Top,” in Wirksworth—Gravel.
“Green Linnet,” West of Brassington—China clay.
Subjacent to the Boulder-clay. 247
“ Hill Top,” South of Middleton, by Wirksworth—Gravel.
“ Leas Vein,” North-West of Wirksworth—Gravel.
“ Time Kilns” and “ Drake,” in Winster—38rd Lime— Gravel.
““Mossey Meer,” in Winster—Ochrey clay.
“ Nursery,” North of Hopton in Dunstone—Soft clay.
“ Portaway Pipe,” in Elton and Winster—Gravel.
“Sand-hole Pipe,” South-West of Wirksworth—Gravel.
“« Seven Rakes,”’ near Matlock Bridge—Gravel, bones, and teeth.
“ Solms,” in Wirksworth and Middleton—Gravel.
“ Suckstone,” in Brassington—China clay.
“Upper Field,” in Brassington—China clay.
In speaking of China clay, at page 447, the same author says:
“China clay of a most beautiful white colour is procured in small
quantities in Bald Mine, Green Linnet, Suckstone and Upper Field
Mines; in the 4th Lime at Brassington; in Clay-pit Dale Mine in
Hartington, etc. ; in a lum or fissure in the 4th Lime, a quarter of a
mile east of Newhaven House; also in a similar lum at Milk Hill
Gate, one mile and a half east of Caldon in Staffordshire ; and per-
haps in other places in this stratum.”
At page 298, Farey observes: “In large open fissures in this rock
(Toadstone), most beautiful white china clay is found, and many
coarse sorts mixed with quartz pebbles, and other alluvia, near
Newhaven House, in Hartington, and at Milk Hill Gate, near
Caldon, in Staffordshire; good fire-clay being also procured at the
latter place, and used at Whiston Copper Works.” Again, at p.
279: “Just by (The Harboro Rocks in Derbyshire) the Yellow
Dunstone seems to produce pits of scouring sand, and near them
excellent clay for brick and tile making.”
Mr. Binney observes in his notes: ‘I have many years since seen
a good bed of potter’s-clay in the Millstone Grit at Spitewinter, near
Stannage, on the west side of the turnpike-road leading from
Chesterfield to Matlock. This may be only of one of the fire-clays
of the lower coals, or it may be like that at Caldon ; I cannot say
positively.”
«The whole of the Mountain Limestone district of North Derby-
shire and the Millstone Grit and Coal-measure strata are free from
foreign drift. J have never seen Till or Boulder-clay in the district.”
Mr. Binney has furnished me with the following sketch (Fig. 5)
of the Fire-clay ‘‘pocket,” at the Caldon Hill Limestone Quarry,
and observes—‘'The vertical bed of rounded pieces of grit and
white Quartz pebbles mixed with sand proves that the whole of
the Clay and Sand now found in the hollow of the limestone was
the débris of the Millstone grit formerly lying above them; but
‘there must have been some strange commotion to account for the
position of the bed of pebbles. It is about five feet wide, and the
diameter of the pocket about thirty feet. The fine sand is used
for the iron furnaces, and the clay, when mixed with sand, for the
manufacture of fire bricks.”
The following description of the distribution of this deposit on the
Weaver Hills, which form the southern extremity, in Staffordshire,
248 Maw—Distribution of White Clays and Sands,
of the Pennine Chain, is from a paper read before the British Asso-
Fig. 5. Sand and Clay Pocket, Caldon Hill Limestone Quarry, Weaver Hills.!
Se oS
y ‘tinge 7343 2 Ne ewens
se
Ss
rene?
anys ae 7 pat
Qb
((
saaaty eye eh Sc sui es war AA AZ 4 #350 wi Yes
Son 92 oY oF Yu A eo , ee bia
ay a oe
, ees ee omy
\
UU) uf ‘aha
ee — vd
5 =
* a a oy 8 8 Fie ‘
"hi eee F.0 U8 eee the deposit, both in position
2 and mineral character, to the
white clays and sands of the
«50 4
6
or ree ms rozs Mountain Limestone district
Oy =a 090-2 ya he 7 ay .
Rit Ormere gargs tevtel PAL gotos ern of North Wales. Some of the
fo FF YS GS> i BE OV, SR os 0 1<,0 ) 2
Gah coie Oss bare cess [fs'shy = leotse-ay.rae Complications of arrangement
_ A. Boulder-clay Till. 3B. Ditto filling up a crack WETC mi VEL remarkable. The
in io Mae rlay Sands and Pebble-beds subse- sand and clay strata occupying
per, the limestone cavities being
‘sloped and twisted into strange contortions, here and there standing
Subjacent to the Boulder-clay. 251
almost vertically, and nearly level beds ending abruptly against those
steeply inclined. The superposition of the Boulder-clay was invariably
evident, and in one or two places I observed thin layers and seams of
the dark Till running in amongst the subjacent lighter deposit, as
though it, at the time of the deposition, had contained open cracks
on its upper surface, as in Fig. 7.
Tn one case it was evident that the deposit had moved after the
deposition of the Till, the continuity of the thin dark lines being
-abruptly broken by what appeared to be small slips in the white
sand and clay beds containing them. This is a point I shall have
further occasion to refer to in the latter part of the paper.
Mr. Brown informs me that—‘ Somewhat to the east of the
Ribden Pit” (from which the example in Fig. 7 was taken) “is
another exposure of the white clay, superimposed by several feet of
Boulder-clay Till: the locality isknown in the neighbourhood as the
Wredon or Sally-Moor Pit; leading up from this past the Ribden
Pit, towards the Red House, are several other interesting pits in this
deposit. At the south-west base of Caldon Low, and close to the road
leading to Caldon village, are two or three pits of rather impure
deposit. From the top of Caldon Low you may trace by the eye
the extension of the bed as marked by the sinkings mentioned in my
paper. North of Caldon Low are two or three other newly opened
excavations.”
[To be concluded in our next Number. |
TIl.—On a Bep or PuospHate or Lime, N.W. oF LiLAnryLtiin,
Norra Wates.
By D. C. Davies, Oswestry.
Aca the meeting of the British Association held in Birmingham
in 1865, Dr. Voelker directed attention to the discovery of a
bed of Phosphate of Lime in North Wales, and entered into par-
ticulars concerning its chemical composition, and economical value.
8. , i :
3
2
River Cain,
Rhosfaw1
’ Das Eithen.
Cefn Grugos
S\-—-— Cwmgwynnen
_ Tanat ValleyE.
of Llangynno
1
Fig. 1. Section showing the general structure of the country near the Phosphate
bed, north-west of Llanfyllin.
1, Rubbly shales, passing upward into soft sandstone, containing Retepora, Favosites, Orthis
elegantula, O. parva, Lepteena simulans, L. teniucincta (Llandovery beds).
2. Schists, in centre of the hill, passing into impure limestone (Uppermost, or Hirnant band, of
Bala limestone).
8. Blue rubbly schists, passing into solid limestone, with bed of Phosphate, A.
4and 5, Levels driven into the hill, the lower one (5) showing the return of the beds to their
natural position. x Quarries.
252 Davies—Phosphate Bed at Lianfyllin.
As this bed occurs in a rich geological district with which I am
familiar, I may be allowed, perhaps, to direct the reader, as briefly
as I can, to a few points of geologic interest connected with it.
The bed occurs in the midst of what I have elsewhere described
as the middle and principal band of Bala limestone; it was first
discovered at Cwmgwynnen, on the road leading from Llanrhaiardar
to Llanwddyn, and has since been traced as a continuous bed south-
west of this spot about two miles, and north-east about the same
distance to Penygarnedd, where, following the course of the lime-
stone, it bends sharply to the south, in the hill Llechwed Llwyd.
I am informed that it has also been found in several places in the
broken lines of Bala limestone north of the town of Llanfyllin.
River Tawar,
Bae 3 456 7 8 §
Fig. 2, Section of strata at Cwmgwynnen mine, north-west of Llanfyllin.
land 2. Dark blue limestone and shales, Orthis elegantula, Lingula longissima.
3. Dark green schists, with Echinospherites, Caryocystites; passing into blue limestone
with Phragmoceras arcuatum, Illaenus Davisii.
4, Black phosphatic limestone, full of concretionary masses, and iron ‘pyrites, with
Orthis flabellulum, O. porcata, Illaenus Davisii.
5. Black Phosphate bed, eighteen inches thick.
6. Layer of Kaolin, passing into solid felspar, sprinkled with copper pyrites.
7. Solid limestone, containing much phosphate,
8. Sandy ash, containing casts of Pterinea.
9. Compact Caleareous ash.
A. B. Levels.
It has been worked somewhat extensively at Cwmgwynnen, and
here it may be studied best. It is black in colour, has an average
thickness of about fifteen inches, and occurs in a bed, as will be seen
by a reference to the accompanying sections, and not as a vein, as is
sometimes stated by our chemical friends. There are plenty of
traces of former life in the bed: thus, I have obtained from it
numerous casts of Modiola, Aviculopecten, Orthoceras, Orthis, Lin-
gula, and fragments of Trilobites ; but the fossils are not well
preserved, their organic structure having apparently been destroyed
by chemical agency. We may then, I think, regard this Phosphate
bed as the remains of a Laminarian zone of sea life, just as the
wide stretching, ferruginous sandy fossiliferous layers, in the same
formation, with their fossils often broken and confusedly huddled
together, are the remains of the Littoral zone of the same period.
The bed, as far as it has already been explored, gives us an area of
four miles long, by about eighty yards in width,—this being the
depth to which it is worked at Cwmgwynnen, in the nearly vertical
strata, and at all the points hitherto examined it maintains much the
King—On Perforated Spiriferide. 253
same thickness and relationship to the adjoining beds. We thus
infer that it was deposited in a somewhat shallow sea, not much
varying in depth, or subjected to disturbing influences. The strata
in which it occurs are rightly marked upon the government maps as
reversed,” dipping, as they do, away from instead of towards the
adjacent Llandovery and Wenlock beds. A level which has been
recently driven through the beds near the base of the hill clears up
this seeming anomaly, for at this depth the beds are seen to bend
towards their true position (as seen in Figs. 1 and 2), thus showing
the upheaving force to have operated from the north or Llangynnog
side, turning up the edges of the strata, as we sometimes, with thumb
and finger, deflect the edges of the leaves of a book. I enumerate the
principal fossils found here, in my explanation,of the sections. I may
however note, that Phragmoceras arcuatum is here found at a point
much lower than its usually assigned limit, it having, I think, been
tabled as an Upper Silurian form only. The number of Cystideans,
too, which are found in the schists above the limestone, is deserving
of notice. There are some very nice specimens of Hchinospherites
and Caryocystites, and also a Cystidean, which to me seems identical
with that figured by Prof. M‘Coy (Pal. Rocks and Fossils, plate 1 d,
fig. 6), as an undetermined Cystidean from Coniston. The country
around possesses many attractions for the geological rambler.
I.—Norss on some Prerroratep PAaLmozoic SPIRIFERIDZ.
By Professor W. Kina.
PIRIFER CUsPIDATUS.—As I am somewhat committed to the
opinion lately enunciated by Mr. Meek,! that this species is
characterized with a canal-system, I may be permitted to make a few
observations on the subject.
In a foot-note appended to page 126 of my “ Monograph of the
Permian Fossils of England,” published in 1850, there occurs the
following passage :—“ Dr. Carpenter states that Spirifer cuspidatus is
a non-perforated shell, which I suspect is an oversight.” As his
“original determination” is still maintained by Dr. Carpenter,’ it
behoves me to adduce what I consider to be in favor of my suspicion.
An imperfectly testiferous specimen, unmistakably belonging to
the species under consideration, and now in the Geological Museum
of Queen’s College, Galway, displays under a hand-magnifier, here
and there, particularly on the protected parts—as the medial
furrow—patches of faint slightly-raised oval impressions: they are
delineated as faithfully as I could in the accompanying figure (See
Woodcut, Fig. 1). Ido not mean to maintain that the appearances
1 See Silliman’s American Journal of Science, May, 1866.
2 See “ Ann. and Mag. Nat. Hist.,” 3rd Series, Vol. xix. January, 1867.
8 The specimen was found in Carboniferous limestone, near ‘luam, by Mr. John
Birmingham, F.R.G.S.I. (who will ever be honoured by his discovery of the
rar cevle star ‘‘ 7. Corone Borealis”), and has been presented by him to the
useum,
254 King—On Perforated Spiriferide.
represented are to be accepted as positive evidences of a perforated
structure; but they bear so strong a resemblance to rather ill-defined
markings, undoubtedly arising from perforations, often seen on meta-
morphosed specimens of Dielasma hastata, and other allied carbon-
iferous species, in their form and arrangement, as to render the
existence of such a structure extremely probable.
To show the resemblance between the impressions in Spirifer
cuspidatus, and those due to the canal-system in Dielasma hastata, I
have given a representation of the latter (See Woodcut, Fig. 2).
They consist, in both cases, of ovals slightly in relief, and separated
from one another by narrow depressed interspaces ; without, however,
any traces of perforations: they are present on different sub-surface
shell-layers.
In palliobranchiate shells, as they usually occur, the outer-surface
of the valves often exhibits the opposite condition, being marked
with excavated ovals, each of which shows a perforation in the middle :
é S\o\
Fig. 1. Fig. 2. Fig. 3.
the internal layers. however, present precisely the same general ap-
pearances observed in the above-named fossils, with the exception of
being perforated. The condition alluded to is clearly caused by the
fibres or prisms, which compose the shell-substance of the valves,
rising up around the walls of the perforations, as may be readily seen
in sections, both horizontal and perpendicular, of Waldheimia Aus-
tralis, and other recent species. Suppose the perforations and
fibres of the latter to be obliterated by metamorphic action, or
mineralization, there would then be presented simply the raised
impressions similar to those occurring in the fossil species.
Sufficient evidence has now been adduced to show my suspicion
to be well grounded; also, that Mr. Meek’s opinion is so far
strongly supported. .
Like Mr. Davidson, I am not disposed to place Spirifer cuspidatus
in the genus Cyrtina ; but if it be really perforated, and there be any
physiological value in the perforations, genus-makers will find in this
species another of the many puzzles that beset their labours. Perhaps,
after all, it may be an aberrant species of Cyrtina, the median or
arch-supporting plate having been arrested in its growth through
atrophy, as appears to have been sometimes the case with the dental
plates in the genus Spirifer.
No doubt Dr. Carpenter had some grounds for introducing my
name into his letter which has lately appeared in vindication of his
“original determination,” on account of the mistake I made in
asserting that certain imperforate palliobranchs are perforated,—
a mistake which was duly acknowledged in one of my papers pub-
King—On Perforated Spiriferide. 205
lished long ago. But it remains a secret with Dr. Carpenter, why
he has been so remarkably reticent on the errors—grave ones too—
committed by himself in connexion with the histology of these
same shells.2, And why Mr. Davidson should have thought it prudent,
or necessary, to mention my name in his testimonial of “ most implicit
belief” in favour of Dr. Carpenter, appended by the latter to the
letter referred to, is another matter which requires at least a passing
notice.
CrrTINé HETEROCLITA.—F rom what has been published of late years
respecting this species, and the genus in which it has been placed by
Mr. Davidson,? justice to myself requires me to make the following
statement.—The principal portion of the apophysary system of the
shell under notice was first made known, I believe, by myself many
years since. J described the large valve as possessing a median
plate, to which are attached, one on each side and at a little distance
from its free margin, the dental plates, so as to form an arch-shaped
process, similar to that in Pentamerus, Camarophoria, and some other
genera. I also announced that its valves are distinctly perforated.
Any one referring to Davidson’s British Fossil Brachiopoda, the
Sandberger’s Die Versteinerungen in Nassau, and certain other works,
in which Cyrtina heteroclita is described, published since my ‘Mono-
graph” appeared, will fail to find a single sentence indicating that
its internal structure and histology had been previously described by
myself. ;
Mr. Davidson has placed Phillips’ Spirifer septosus in his genus
Cyrtina; but he appears to have overlooked the question, as to
whether, or not, it is perforated. Suppose this species to be im-
perforate : How are we to reconcile its being placed congenerically
with COyrtina heteroclita, which has well-marked perforations ?
Should Spirifer septosus prove to be unprovided with a canal-system,
I would, in this case, have no hesitation in removing it from Cyrtina ;
for, although I am no believer in the view which assigns the function
of respiration to the perforations, I attach sufficient importance
to them to consider that they form a good generic character.®
Perhaps they are even diagnostic of a family, or sub-family ?
As the canal-system of Cyrtina heteroclita has only been imper-.
fectly illustrated by other observers, I have given a transverse
1 See “ Ann. and Mag. Nat. Hist.,” 2nd Series, Vol. xviii. April, 1856.
2 See ‘“‘ Reader,” August 19th, 1865; and the paper cited in the last foot-note,
with reference to the ‘thin sharply-folded micaceous plates” (now admitted by
Dr. Carpenter to be fibres, or prisms), forming the shell-substance of the Pallio-
branchiata; also “Ann. and Mag. Nat. Hist.,’”? 2nd jSeries, Vol. xix. p. 214, etc.,
respecting the ‘mere pits upon the internal surface’’ of Rhynchopora Geinitziana
(now proved, as I originally considered them, to be perforations of the canal-system,—
See, op. cit., 2nd Series, Vol. xvii. p. 506; 3rd Series, Vol. xvii. p. 230-2388).
3 Ts this species the type of Cyrtina?
4 See “Ann. and Mag. Nat. Hist.,” Vol. xviii. p. 86, 1864; and pre-cited
“ Monograph,”’ p. 68, 123, and 124.
5 See my “‘ Monograph on Permian Fossils ” (Pal. Soc.), p. 126.
6 In a memoir, in course of publication, ‘On the Histology of the Test of the
Palliobranchiata,’’ I have given some facts and evidences which are strongly opposed
to the respiration view.
256 Nicholson—On Graptolites.
view of it (See Woodcut, Fig. 3). How remarkably similar are
the histological elements—perforations and fibres—of this species
with those (particularly the ‘‘ mere pits”) of Rhynchopora Geinitziana!'
According to Mr. Davidson, “it is certain that no vestiges of
spiral coils have hitherto been noticed by any author” in species of
Cyrtina :? possibly they will always remain wnnoticed in the so-called
Cyrtina septosa, M‘Coy’s Pentamerus carbonarius, and certain other
presumed congeners. However, be this as it may, Cyrtina heteroclita
is undoubtedly a Spiriferid; as one of my old specimens, of the set
which disclosed to me the apophysary system previously noticed,
exhibited the spiral appendages very distinctly.
Sprrirerina, D’Orbigny, 1847.—This genus, which was separated
by its author from Spirifer in a great measure on account of being
perforated, appears to have its nearest affinities to Cyrtina, as typified
by OC. heteroclita. Both genera have the normal canal-system. In
Spiriferina the dental plates are not attached, as in Cyrtina, to the
median plate: the latter is large, situated between, and independent
of, the former,—as was shown in my previously cited paper of 1846.*
I urged sundry objections against Spiriferina in 1850, one of which
arose out of the mistake I committed in concluding that all the
Spiriferide are perforated; but I have for some time past thought,
with Mr. Davidson, who was not hampered with this error, that the
genus is a good one.
TV.—On a new Genus or Grapronirrs, with NotEs on
Repropuctive Bopizs.*
By Henry Atteyne Nicuotzson, D.Sc., F.G.S.
Baxter Scholar in the Natural Sciences in the University of Edinburgh.
(PLATE XI.)
{| tear Graptolite which I am about to consider is perhaps one of
the most remarkable of all our known British forms, and was
originally described by Mr. W. Carruthers,’ under the name of Clado-
grapsus linearis. The genus Cladograpsus is one which was proposed
by Geinitz to include certain forms of Didymograpsus; but Mr.
Carruthers seems subsequently to have seen that the reference of
G. linearis to this genus was inappropriate, as he has recently alluded
to it, under the title of Dendrograpsus linearis. The genus Dendro-
grapsus of Hall includes certain branching Graptolites, which are
peculiar to the Quebec group in America, and which do not occur, as
far as is yet known, in the Skiddaw slates—our undoubted repre-
sentative of the Quebec series. The genus, in fact, appears to be
characteristic of the Lower Llandeilo period, the only known British
1 See a similar view of the histology of this species given in the ‘Ann. and
Mag. Nat. Hist.,”’ 2nd Series, Vol. xvii. plate xii. fig, 11, 1856.
2 See “ British Carboniferous Brachiopoda,’’ p. 68.
3 See “Ann. and Mag. Nat. Hist.,’”’ Vol. xviii. p. 86; also pre-cited ‘“‘Mono-
graph,” p. 68 and 128.
4 Read before the Geological Society of Edinburgh, March 21st.
5 Annals and Magazine of Nat. Hist., Vol. iii. No. 13.
6 Geox, Maa., Vol. 1V., No. 2, p. 70.
Geol: Mag: 1967. oes : Vol.LV, FU XI.
/
HANicholeon det! E. F.
GRAPTOLITES FROM DUMFRIESSHIRE
Pr
sage stmt acts AEN,
rit
Nicholson—On Graptolites. 207
species—the Dendrograpsus furcatula of Salter—occurring in rocks
of this age in Wales.' The generic characters of Dendrograpsus are
the possession of a strong foot-stalk, sub-dividing more or less
dichotomously into numerous branches and branchlets, which are but
slightly divergent. Neither the main stem nor the primary branches
are celluliferous, and the whole forms a “broad, spreading, shrub-like
frond.” ? Dendrograpsus, in fact, more nearly approaches in external
appearance to some of the Hydroid polypes of our own seas than,
perhaps, any other of the true Graptolites. In referring G. linearis
to Dendrograpsus, Mr. Carruthers appears hardly to have appreciated
its peculiar and perfectly unique character, and an examination of a
large number of specimens has led me to the conclusion that it
cannot possibly be ranged with any genus yet described, but that it
must be considered as constituting the type of a new genus, which I
propose to term Plewrograpsus, and of which the following are the
generic characters :—
Pleurograpsus, gen. noy. (Plate XI. Figs. 1-5).—Entire frond consisting of two
celluliferous stipes, diverging horizontally, or nearly so, from a common point (which
is usually radiculate), and giving off branches at uncertain intervals, sometimes from
one side, and sometimes from the other, with an irregular alternation. Both the
main stem and the branches are uni-serrate, or monoprionidian. Branches coming
off, usually, nearly at right angles, extending for a considerable distance, and some-
times giving off secondary branches, in a manner strictly analogous to that seen in
the parent stipes.
If we imagine a long Didymograpsus, such as D. flaccidus, Hall, extended into a
straight line, and giving off branches from both sides nearly at right angles, these in
some cases again, and similarly, sub-dividing, we shall have some idea of the general
plan of Pleurograpsus. The existence of secondary branches seems not to have been
noticed by Mr. Carruthers; but, though rare, I have observed them in a well-marked
form in more than one specimen. Even tertiary branches may possibly exist, though
I have never seen any traces of them. The parent stipes diverge from an initial
point, round which the parts of the frond are grouped with something like bi-lateral
symmetry, and which is usually marked by a long and slender radicle (Fig. 2). The
radicle is, however, not infrequently absent or inconspicuous (Fig. 3), when the
base of the organism is only to be detected by the existence in the main stipe of a
point, from which the denticles are given off in different directions. The absence or
presence of the radicle is not, however, a matter of generic importance.
From the description I have given it will be evident that Plewro-
grapsus presents us with a compound Graptolite, branching in a
manner totally distinct from that known in the complex ramose
species of the Skiddaw slates and Quebec group, and equally different
from any hitherto described species from other formations. The
essential point of distinction lies in this, that in all the genera of the
branching Graptolites yet described, (with the exception of the Didy-
mograpst), there is a non-celluliferous stem—the ‘‘funicle” of Hall—
of which the celluliterous branches are secondary or, rarely, primary
offsets. In Pleurograpsus, on the other hand, the primitive parent
stem is itself celluliferous, and is therefore functionally distinct from
the ‘“funicle,” as defined by Hall; the latter, if represented at all,
finding a rudimentary homologue in the radicle of Pleurograpsus.
This total absence of the funicle in Plewrograpsus, alone of all the
1 Mem. Geol. Survey, Vol. iii.
? Hall, ‘ Graptolites of the Quebec Group,” pp. 126, 127. Plate xvii.
VOL. IV,—N@,. XXXVI. 17
258 Nicholson—On Graptolites. .
branching Graptolites, is of itself sufficiently important to constitute
a generic character, and a distinction of equal weight is found in the
mode of branching. The compound Graptolites of the Quebec group
either radiate from a central, non-celluliferous, branching funicle, as
in Dichograpsus, Tetragrapsus, and Retiograpsus, or divide repeatedly
from a basal, non-celluliferous stem, or foot-stalk, as in Dendro-
grapsus and Callograpsus. 'The only Quebec species which show any
affinity to the genus Plewrograpsus, as above defined, are Graptolithus
Richardsoni, and G. ramulus,! which are placed by Hall in his ex-
tremely comprehensive and ill-defined genus Graptolithus. It is
very possible that these might, with propriety, be grouped under
Pleurograpsus ; but such an arrangement would at present be pre-
mature, as they are only known in part. Leaving the Skiddaw and
Quebec group, one branching complex form alone remains for
consideration, and this—the Graptolithus gracilis of Hall—is found
in the Utica state of America.’ This small but beautiful Graptolite
has lately been recognised in Ireland, and I am informed by Professor
Harkness that it is probably identical with the Rastrites Barrandi,
described by himself from the Dumfriesshire shales.? It should form
the type of a new genus, and is at once distinguished from Pleuro-
grapsus by the possession of a non-celluliferous stem, or “ funicle,”
from which celluliferous branches are given off with perfect regularity
and on a definite plan.
The genus Pleurograpsus cannot at present be asserted to contain
more than a single species, viz., P. linearis; some specimens are
more robust in their habit than others, and some, as I have said,
sub-divide more than once; but I think these should be considered
as mere varieties.*
Plewrograpsus linearis, Carruthers sp., Spec. Char.—Frond spreading and com-
pound, consisting of two stipes diverging usually from a long and slender radicle, and
giving origin to primary, and sometimes secondary, branches in the manner described
under the genus. Both the main stipes and the branches are monoprionidian, narrow
at their origin, and gradually widening out, till a breadth of nearly one-twentieth of
an inch may be attained. The main stipes appear to terminate by curving upwards
in the manner of a branch. Solid axis usually invisible, or seeming sometimes to
exist as an impressed line along the back of the stipe. Common canal well marked,
about half the breadth of the stipe. Cellules eighteen to twenty in the space of an
inch, narrow, inclined to the direction of the axis ata very small angle. Denticles
remote, angular, projecting slightly beyond the margin of the stipe; their upper
margins at right angles to the axis, and extending about half-way across the breadth
of the stipe (Plate XI. Figs. 1-4).
Loc.—Hart Fell and Glenkiln Burn, in Dumfriesshire.
The length of this beautiful and very remarkable Graptolite appears
to have been almost indefinite, and Mr. Carruthers states (op. cit.
supra) that he has succeeded in tracing one specimen for nearly
three feet. In connection with this species I have observed a very
' Hall, op. cit. supra, pp. 107, 108. Plate xii.
2 Pal. New York, Vol. i. and iii, 3 Quart. Journ. Geol. Soc., Vol. ‘xi.
* Since the above was written I have come across a small Graptolite in the Skiddaw
slates, which I think is referable to the genus Pleurograpsus. I shall, however,
reserve the description of this species for the present, as belonging more properly to
a paper, which I am preparing, on the Graptolites of the Skiddaw series.
Nicholson—On Graptolites. 259
curious phenomenon, which is of importance if duly confirmed by
further researches. In a specimen kindly lent me by Mr. D. J.
Brown of Hdinburgh, the stipe is studded with small rounded
tubercles, about as large as the head of an ordinary pin, and ap-
parently springing from the common canal on either side (Plate XI.
Fig. 5). As nothing of this kind normally exists in any Graptolite,
I am inclined to believe that we have here an instance of ovarian
vesicles in their young condition, which may either remain per-
manently attached, or may possibly become free at a later stage. If
this conjecture should prove to be correct (and it is difficult to see to
what else these bodies could be referred), it will form another, and
a strong, confirmation of the view that the Graptolites should be
classed among the Hydrozoa. I am, however, bound to admit that
this is the only instance in which I have succeeded in detecting these
bodies, so as to be able to speak with certainty as to their existence..
I certainly think I have seen similar tubercles in other specimens of -
P. linearis, and also in Diplograpsus bicornis, Hall; but the difficulties
of observation are very great, and I should not like to make any
positive assertion on this point.
This leads me to make a few remarks upon the bodies recently
described by myself, as being probably the “ gonophores,” or ovarian
vesicles, of Graptolites (Gnot. Mac., Vol. IIT. p. 488, Plate X VIL),
concerning which I have been fortunate enough to obtain further
and more conclusive evidence, in a series of well-preserved specimens.
When perfect, and compressed laterally, these bodies are oval, bell-
shaped, pyriform, or rounded, provided with a mucro at one extremity
(the proximal ?), and surrounded entirely by a filiform border re-
sembling in texture the axis of a Graptolite (Plate XI. Fig. 8).
When more advanced in growth the capsule apparently ruptures,
and the distal margin then becomes ill-defined and irregular, owing
to the destruction and absence of the border above mentioned (Plate
XI. Fig. 9). When compressed from above downwards, the mucro
is to be found somewhere within the circumference, as an elevated
point surrounded by several concentric, cireular, or elliptical rings
(Plate XI. Figs. 10-11). The resemblance in these cases to orbicular
Brachiopods is purely mimetic and illusory, and could not deceive
anyone who had examined a large series of specimens. They are at
once distinguished by their often large size, by the irregularity of
the concentric rings, by the variable position of the mucro—which
is sometimes centric, sometimes eccentric—and by their total want
of any persistent figure, outline, or striation; while their texture is
graptolitic, and entirely different from that of any Brachiopod, such
as the Siphonotreta micula. In the case of that variety—if variety
it be—of Graptolites Sedqwickii, described by Professor Harkness!
under the name of Rastrites triangulatus, I believe I have now made
out with certainty, that these capsules are reproductive in function,
having obtained them in attachment in such numbers, and under
such circumstances as seems to preclude the possibility of accident.
They seem, however, to become detached before they attain their
1 Quart. Journ. Geol. Soc., Vol. vii.
260 Nicholson—On Graptolites.
full growth and size, and the specimen, which I figured in the paper
J have alluded to,’ appears really to have been an instance of mere
juxta-position. The mucro would seem to be the point of attachment,
and the organ whereby it is effected, as we might expect from
analogy; but I have no certain evidence in support of this view.
The capsules apparently arise from no absolutely constant point of
origin, some springing from the common canal (Plate XI. Fig. 16),
others from the apex of a cellule (Plate XI. Figs. 14-15), and
others from the under-surface of a cellule (Plate XI. Figs. 13-14) ;
the last two modes being the most frequent. The largest capsule
which I have seen attached in this way has not measured more than
one-tenth of an inch in diameter, many being much smaller. After
attaining this size they seem to become detached; numbers, often
nearly half an inch in length, occurring in this condition in the
shales, along with innumerable germs. The sequence of phenomena
thus described has not been observed by me in any other Graptolite
except G. Sedgwickii; but it accords perfectly with the excellent
description and figures given by Hall of the reproductive process in
D. Whitfieldii.2 I have myself in many instances seen bodies essen-
tially similar to those described by Hall, though not so well preserved,
attached to the stipe of this same species from the Dumfriesshire
shales, and their occurrence appears to me to be inexplicable, except
on the hypothesis that they are reproductive.
In certain other beds in the same locality (viz., Garple Linn), in
which G. sagittarius is the prevailing form to the almost total ex-
clusion of G. Sedgwickii (Rastrites triangulatus), and in which the
capsules occur in the greatest profusion, I have, nevertheless, failed
to detect any organic connexion between the two. I should be
inclined to explain this by the belief, that the gonophores of G.
sagittarius were thrown off when still extremely minute, subsequently
attaining their full developement. This view is borne out by the
occurrence of these bodies in all stages of growth, from small rounded
bodies, not bigger than a pin’s head, up-to nearly half an inch in
length, and it is further supported by analogy with many of our
recent Hydrozoa. I may observe, too, that in the rare instances in
which G. Sedgwickii is found in this bed, the capsules are found
attached just as in the specimens from the beds, in which it is the
dominant species. If this view is not correct, it is still possible that
in the case of G. sagittarius and, perhaps, other species, the gono-
phores were attached to the sides of the polypites, or to ‘“gono-
blastidia,” as in many living Hydrozoa. In this case the capsules
would, of course, never be found in organic connexion with the
Graptolites in a fossil condition. Another difficulty is presented by
the existence of beds like those of Hart Fell, where Graptolites are
very abundant, but where the capsules do not appear to occur at all.
Here, however, all, or almost all, the known species except Plewrograp-
sus linearis are referable to the genera Diplograpsus and Didymograpsus ;
whilst G. sagittarius, G. Sedgwickii, and other common monoprionidian
1 Op. cit. supra, Plate xvii. Fig. 3.
2 “Graptolites of the Quebec Group,” p. 38. Plate B, Figs. 6-11.
Nicholson—On Graptolites. 261
species are, as far as my experience goes, totally absent. In the
case, then, of the Hart Fell species, such as Diplograpsus pristis, D.
teretiusculus, D. mucronatus, Didymograpsus flaccidus, D, sextans, etc.,
it might be assumed with some probability, that the gonophores
were unprovided with a corneous envelope, and were therefore in-
capable of leaving any traces of their existence. I do not, of course,
assert that this absolutely was the case; I merely start it as an
hypothesis, capable of explaining the apparent absence of the capsules
in certain localities. Whilst cases such as the above occur, it should
be borne in mind that the capsules have never yet been found except
in rocks where Graptolites abound; whilst they present the most
striking similarity in form to the gonophores of many recent Hydro-
zoa. Further, if the capsules do not stand in some relation to the
Graptolites, but are to be considered as independent organisms, it
appears to me that the paleontologist will be compelled to create a
new family for their reception ; since, I venture to say there is no
known genus, or family, to which they could with any likelihood be
referred. I may add, finally, that even in the total absence of re-
productive bodies, or of any proofs of their direct connexion with
the Graptolites, I should still think the evidence very strong against
the view, that the Graptolitide are referable to the Polyzoa. I rest
this statement upon the fact, that the true Graptolites (omitting
Dictyonema, and with the possible exception of Dendrograpsus and
Callograpsus) are all free, whilst the Bryozea are invariably fixed ;
upon the undoubted presence of a “common canal” in many,’ if not
in all, of the former; upon the mode of growth and nature of the
embryonic forms ; upon the absence of calcareous matter in the test ;
and upon the existence of allied forms, like Corynoides. Should the
views, which I have briefly expressed concerning the nature of the
“ capsules,” be confirmed by future and more extended observations,
the zoological position of the Graptolitide will no longer be a matter
of doubt, and they can unhesitatingly be classed amongst the Hydro-
zoa. This is a subject which I trust to take up hereafter in greater
detail, and I must at present content myself with stating that I do
1 T altogether question the absence of the ‘‘ common eanal” in any true Graptolite ;
though Mr. W. Carruthers has recently denied that it exists as a distinct structure,
referring especially to Diplograpsus pristis, His., D. folium, His., D. cometa, Gein.,
and Graptolites sagittarius, Linn. (Grov. Mac. Vol. IV. p. 70). In this opinion Mr.
Carruthers stands, I believe, alone amongst those who have written on the subject ;
and Hall’s observations in particular appear to be almost conclusive against it. Thus
Hall has shewn (‘‘Graptolites of the Quebec group,” p. 28, pl. A, figs. 4, 5, 9) that the
cell-partitions may extend'to the axis, and may, nevertheless, leave room for a common
canal, as in D. bicornis. The mere fact, therefore, that the cell-partitions reach the
axis, as they certainly seem to do in D. folium and in D. cometa, does not justify us
in asserting that there is no common canal, in the absence of sections such as those
made by Hall. In the case of D. pristis and G. sagittarius I believe that Mr. Car-
ruthers is in error, and that the cell-partitions do not really reach the axis, at any
rate in full-grown specimens. In D. pristis, His. I have observed conclusive
evidence of the existence of the common canal as a distinct structure, since the axis,
where prolonged beyond the distal extremity of the stipe, is in some specimens
bordered by the common canal on both sides, the cellules alone being wanting, either
because they have fallen off previously to fossilization, or because they had not yet
been developed.
262 Nicholson—On Graptolites.
not think the Graptolites can be referred to any known order, or
even sub-class, of the recent Hydrozoa. In many external characters
they certainly appear to approximate closely to the order Sertularide;
but they are at once excluded from the entire sub-class of the
Hydroida by the fact that the polypidom (in the true Graptolites at
any rate) was free, and was not fixed by a “hydro-rhiza,” there
being other important differences as well. As far as the evidence
yet collected goes, I should be disposed to believe that the Grap-
tolitide will have to be placed in a new sub-class, which will occupy
a position intermediate between the fixed and the oceanic Hydrozoa.
I may conclude this paper by a short description of a species of
Diplograpsus, seemingly distinct from any known form, which I have
named after my friend Professor Harkness, to whose researches we
owe most of our knowledge of the Graptolitic rocks of Dumfries-
shire. The characters of the species are so peculiar that I feel quite
justified in describing it as new, though I possess but a single
specimen.
Diplograpsus Harknessii, n. sp. (Fig. 6), Spec. Char.—Stipe three-tenths of an inch
in length, and about a line in breadth, celluliferous on the two sides. Solid axis pro-
jecting slightly beyond the end of the stipe, slender and inconspicuous. Cellules
about thirty in the space of an inch, alternating slightly with one another; united
internally ; but free externally on both sides for about half their length. In the
lower half of the stipe the cellules are more closely set, and are only free below. The
cellules form somewhat quadrangular tubes, the free extremities of which are bifid, or
bi-labiate. In the lower cellules the inferior prolongation of the cell-mouth is fur-
nished with a bi-furcate spine or mucro, one arm of which is directed upwards, the
other downwards ; but in the upper cellules the spines are not well-preserved, and
sometimes appear to be undivided.!
Loc.—Hart Fell, near Moffat.
Germs of Graptolites—On the surface of the same slab as the preceding are two
or three germs apparently belonging to the same species. Each of these (Plate XI.
Fig. 7) consists of a delicate mucro, or radicle, surmounted by an oval mass, which is
indented at the sides, the primary cellules being furnished with spines at their apices.
In the shales of Dobb’s Linn I have recently observed certain bodies exactly re-
sembling in form the di-prionidian germs, so common in all the Dumfriesshire beds,
but of a very much greater size. They consist of a long and slender radicle, about
four-tenths of an inch in length, with a central solid axis, and with a semi-circular
lobe at the top on one side (Fig. 17). Another lobe soon appears alternating with
the first, and on the opposite side of the axis (Fig. 18); and when more advanced two
more lobes are super-added to these. These bodies would seem to be the germs of
some di-prionidian Graptolite, perhaps of D. teretiuscoulus ; but their great size is very
remarkable and anomalous, the ordinary germs (Fig. 19) being little more than one-
twentieth of an inch in length.
EXPLANATION OF PLATE XI.
Fig. 1. Pleurograpsus linearis (Carruthers sp), nat. size, The denticles are made
much more distinet than they are in nature, for purposes of illustration,
and the radicle is put in—though not shown in this particular specimen.
Fig. 2. Commencement of P. /inearis, showing the long and slender radicle. Enlarged.
Fig. 3. Ditto, without a radicle. Enlarged.
‘ I take this opportunity of stating that I now am inclined to believe that one
variety, at any rate, of the Diplograpsus tubulariformis, which I lately described from
the Moffat shales (Gzox Mac., Vol. IV. p. 109, Plate VII. Figs. 12-13), is really
identical with D. cometa, Geinitz, and must therefore be abandoned as a distinct
species. Geinitz’s description, however, and figures have been founded on imperfect
specimens, and do not recognise the essential characters of the species,
Jevons— Duration of S. Stafford Coal-feld. 263
Fig. 4. Portion of P. dinearis, enlarged to show the cellules.
Fig. 5. Fragment of the stipe of P. linearis, showing reproductive (?) tubercles.
Enlarged. ;
Fig. 6. Dipligrannis Harknessii, n. sp. The straight line beside it shows the
natural size of the specimen.
Fig. 7. Germ, probably of the same. Enlarged.
Fig. 8, Ovarian capsule, or Gonophore, unruptured, showing the strong external
border. Enlarged. :
Fig, 9. Another, after rupture has taken place. Enlarged.
Figs. 10 and 11. Ovarian capsules, compressed vertically. Enlarged.
Figs. 12 to 15. Graptolites Sedgwickii (Rastrites triangulatus, Harkn.), with ovarian
capsules attached to the cellules. Enlarged. :
Fig. 16. Another specimen, where the capsule appears to come from the common
canal. Enlarged.
Figs. 17 and 18. Germs of a di-prionidian Graptolite (?). Natural size.
Fig. 19, Ordinary germ of the natural size, introduced for comparison.
NOTICES OF MEMOTRS.
pEaE Bele
J.—ON THE PROBABLE DuRATION OF THE SOUTH STAFFORDSHIRE CoaL
Frexp."
By W. Sranuey Jevons, Esa., M.A.
1 ek some years there had been considerable anxiety concerning the
supposed exhaustion of the Coal-fields, but it was only since 1860
when Mr. Hunt published his work upon the subject that the nation
seemed to have been aroused to a sense of its importance. But this
feeling of interest might be traced back as far as 1789, when John
Williams seemed struck not only with the inestimable value of coal as
the chief motive power of the country, but he also seemed to under-
stand that it was necessarily of limited quantity. Previous to this time
it was supposed that coal was a constant growth, filling up again the
vacant places in the strata where it had been taken out. The fallacy
of this theory, however, was soon discovered; and from that time
the unfortunate circumstance that coal was necessarily limited was
known and acknowledged. Mr. Jevons referred to the various
writers and speakers who had of late shown so much interest in the
great question as to the probable exhaustion of our coal fields, which
had aroused the attention of the whole nation, and had now culmi-
nated in the appointment of a Royal Commission to investigate it.
Mr. Jevons explained the method of proceeding by which this com-
mission are prosecuting their enquiries, referring to each of the
sections into which it is divided, and specifying the particular class
of information which each section more especially seeks to obtain.
On that occasion he did not intend going over the ground which had
been trodden by other gentlemen, who were far better acquainted
than he was with the resources of this particular locality. He
wished, however, to offer some suggestions relating to the more eco-
nomical use of coal in this country. First, he must notice the results
of the inquiry of Mr. Mathews, contained in a paper published in
the Transactions of the Society of Mechanical Engineers, which put
the geology and the technical data in the clearest possible light.
1 Being the substance of a Lecture delivered by Mr. Jevons at the Midland In-
stitute, Birmingham, 25th March, 1867.
264 Oldham—Coal Resources of India.
That gentleman considered that in the eastern part of this field,
which lies north of Dudley, the unworked part consisted of only
1,160 acres, and allowing 20,000 tons per acre for the first and
second workings, the total remaining in 1860 was 23,200,000 tons.
Now the rate at which coal is being drawn annually was stated at
550,000 tons, and a simple division gave the probable duration of
this part of the field as only forty-two years. In the western dis-
trict, which lies upon the opposite side of that range of which Dud-
ley fone a part, there are estimated to be 2,785 acres, which at
20,000 tons of coal per acre gave 55,700,000 tons. The rate of
working was 14 millions of tons per annum, and a simple division
gave thirty-seven years as its period of duration, supposing the
demand and consumption to remain as it was. Thus it might be
fairly said, that in less than half a century the thick coal of South
Staffordshire, which is the most perfect store of fuel any nation has
ever possessed, will be perfectly exhausted. The question now arises
whether pits can be pushed down upon the flanks of this field with
a chance of finding the thick coal again. The South Staffordshire
field, however, had not the advantage of some other fields, where
the strata dip gently and continuously down, and where you may
be almost certain of meeting the original beds of coal, but the strata
in the South Stafford field were much more irregular. This field is
described by Mr. Beete Jukes as a Palaeozoic island, pushed up through
the Red Sandstone which extends over the larger portion of the centre
of the country. The field had been forced up by volcanic power,
which alone was a great obstacle to the exploration of coal, since
they did not know at what depth down the strata might be found.
Thus, in some places 1,000 to 15,000 feet of Permian strata might
intervene between the coal, whilst at other times it might be absent.
The lecturer went on to remark how greatly this part of the country
depended for its industry upon the coal to be obtained in its neighbour-
hood, and proposed that the sinking of deep shafts for the purpose of
discovering coal, should be undertaken at the public expense, when,
if the coal was found, the owner of the field should be required to
return the money expended, perhaps even with some interest. Mr.
Jevons alluded to the shafts which had been sunk in the outskirts of
the coal district for the purpose of ascertaining whether coal was to
be met with, making special allusion to the workings of Mr. Dawes,
at Halesowen, which, however, had not at present proved very suc-
cessful. The great quantity of coal used in this district was called
attention to, and the gradual rise in price of coal, and the iron trade
generally, of this part of the country, and its probable decline, were
touched upon.
II.—Tuer Coat Rzsources or Inpra.
By Dr. T. Oxpuam, F.R.S., F.G.S., Superintendent of the Geological Survey of
India. Calcutta, January, 1867.
[Being a Return called for by the Right Hon, the Secretary of State for India.]
IEWED as a coal-producing country, the British territories in
India cannot be considered as either largely or widely sup-
Helmersen— Coal of Russia. 265
plied with this essential source of motive power. Extensive fields
do occur, but these are not distributed generally over the dis-
tricts of the Indian empire, but are almost entirely concentrated in
one (a double) band of coal-yielding deposits, which, with large
interruptions, extends more than half across India from near Calcutta
towards Bombay. Dr. Oldham has illustrated the areas from which
supplies of coal may be looked for with” any prospect of success, by
amap, on which are marked those parts of the country of which
sufficient knowledge is known to enable him to assert, that there is
no probability whatever of any deposits of coal being found within
their limits, or where, if coal do exist, it must be found at such a
depth below the surface that it could not be economized. On the
same map he has indicated, so far as the scale will admit, the true
limits and outline of those coal-fields which are known. Of a very
large portion of these coal areas detailed examinations have been
made, and descriptions published by the Geological Survey of India. °
Until all the fields have been carefully mapped, any estimates of the
coal resources and production of British India must be defective. Up
to the present time it may be said that little more than surface work-
ings have been carried on in India. The deepest pits scarcely
exceed seventy-five yards, while certainly one-half of the Indian coal
which has been used up to the present date, has been produced from
open workings or quarries. In forming an estimate of the value of
the coal before it has been worked to a sufficient extent to admit
of its quality being tested by practice, Dr. Oldham has been guided
by a series of analyses of specimens obtained from the several coal-
fields. 'The average composition of 74 specimens of the coal gives—
Carbon, 52.2; volatile matter, 31.9; ash, 15.5. Now as the relative
duty or effective power of coals may be taken to vary directly as the
amount of fixed carbon which they contain, Dr. Oldham concludes
that, out of the whole series of Indian coals, the very best of them
only reach the average of English coals, and that on the whole they
are very inferior to them.
IJI.—Tue Coat or Russta.
By Lieut.-General G. pz Hetmersen,
[Des gisements de Charbon de Terre en Russie. 8vo. St. Petersbourg, 1866, pp. 58.]
N this small pamphlet the author discusses the properties, geo-
graphical distribution, and present applications of the Russian
coal, and points out in what localities it may profitably be worked.
Although our knowledge of the geological constitution of Russia is
far from complete, yet sufficient is known to determine the extent of
the workable coal deposits. They have been met with of Tertiary,
Jurassic, and Carboniferous age.
Beds of Tertiary coal occur on the right bank of the Dneiper, near
Kier, where they have been worked with profit. Tertiary Lignite
beds are found in the neighbourhood of Orenbourg; they are, how-
ever, poor in quality.
The Jurassic coal is met with near Koutaiss, in the Trans-Caucasian
266 Reviews—Ansted’s Physical Geography.
region. It is, however, neither sufficiently abundant nor of such a
quality as to be worth the cost of working.
Coal of Carboniferous age is developed—
1. On the eastern and western slopes of the Oural mountains.
2. In the governments of Novgorod, Iver, Moscow, Kalouga, Toula,
and Riazan. The coal occupies a large elliptical basin, six
hundred versts in length and four hundred in width, in the
centre of which the town of Moscow is situated.
3. In Samara, a little peninsula formed by the river Volga, near
Stavrpool; and
4. In the government of Ekaterinoslav, where the coal-beds form a
chain of low mountains called the Donetz, and are associated
with abundant deposits of iron, which latter have not at
present been worked for economic purposes; though they
would well repay the cost.
The Carboniferous beds of Russia all belong to the lower member
of the Carboniferous system, equivalent to the “ Carboniferous lime-
stone” of Great Britain. The Russian beds, however, are mainly
composed of sandstone, with intercalated beds of limestone and coal.
In a map which accompanies the pamphlet, the author has carefully
indicated the extent of Carboniferous strata in Russia, and has in-
serted, also, the railways in order that their respective relations may
be understood. It is to the want of railways that the coal and iron
resources of the Oural, and of the Donetz mountains, have not been
rendered available to anything like the extent to which they are
capable.
The author concludes by expressing a hope that before long
Russia will not be dependent upon foreign countries for the supply
of iron and coal it requires, when it is so largely developed in its
own dominions.
REVIEWS.
J.—Puystcat GrograpHy. By Professor D. T. Anstrep, M.A.,
F.R.S., F.G.S., ete. Wm. H. Allen and Co., 18, Waterloo Place,
Pall Mall, London. 1867.
HE well known author of several geological works has recently
given to us this highly interesting volume upon Physical
Geography ; attaching a very wide signification to the name, and
entering at considerable length into statements of a multitude of
subjects belonging to, or connected with, physical science.
The impossibility of treating this science in such a manner as to
render it light reading is noticed in the preface, and the object of the
volume is stated to be to enable the general reader to obtain an
outline of its main facts, in language as simple and definite as
possible. It is further said to involve ‘not only a statement of
numerous facts, but a great classification of facts, and much close
reasoning,” and also, ‘it needs an effort on the part of the reader to
appreciate the array of facts and observations on which it is based ;
Reviews—Ansted's Physical Geography. 267
the labour of reducing such observation to systematic results and the
deductions drawn from the facts and generalizations.”
In expressing deductions from the facts, the author says he has
perhaps in some cases “given his own views without pointing out
that other physical geographers and geologists have expressed, and
still hold, different opinions. It was not his object to enter into a
discussion upon any subject, and he believes that where the conclu-
sions arrived at differ most from popular notions, they are not incon-
sistent with the views of those who are recognised both in England
and on the Continent as the ablest pioneers of science.” The pre-
face concludes with a recommendation to use Johnston’s Physical
Atlas as a companion to the work, in order to supply a very im-
portant deficiency in the absence of all maps or illustrations.
No special list of authorities consulted is given, though several
acknowledgments of quotations, etc., occur as foot notes or in the
body of the work; and, indeed, the “array of facts” which have
been collected with great apparent care from the latest and best
sources of information, would, it may be presumed, render a general
list anything but an easy task to compile. The author’s personal
observations are seldom separated from those collected from other
sources ; and while the whole volume contains the record and classifi-
cation of a vast number of these, special cosmical theories are in
general but obscurely or partially advocated, and the labour of
drawing deductions respecting them is left largely to the reader.
The volume is divided into six parts, under the headings, InTRo-
puction, Earra, Warer, Arr, Fire, and Lire. Of these, if we
except sundry passages in other parts of the work, the three called
Earth, Water, and Fire—comprising less than half of the volume—
are devoted to those subjects vulgarly or popularly supposed to
constitute the science of Physieal Geography.
In the first chapters the earth is considered as a planet, and
physical forces are treated of. Here, within thirty-two pages, more
than eighty subjects,—astronomieal, terrestrial, chemical, electrical,
or othérwise physical,—are dealt with; so that thus far the general
reader has to thank Professor Ansted for a rather comprehensive
outline of such matters in connexion with physical geography. In
this place also (p. 7), on the subject of the earth’s interior, we find
the following :—-“There is no reason to suppose that any granite
with which we are cognizant has been formed even at so great a
depth as twenty miles, a distance so small compared with the earth’s
diameter, that it fails to have any value in guiding us to a know-
ledge of the more distant material of the real interior. At that
greatest depth it seems clear that the ordinary surface conditions,
acting upon ordinary surface materials, might and would have pro-
duced the rocks we find. They may, therefore, be nothing more
than altered conditions of such rocks as are still formed and de-
posited in our seas.” But while the views of Professor Thompson
and Mr. Hopkins, regarding the earth’s rigidity, find favor, and the
likelihood is stated that, at least, half the distance from the surface
to the centre of the earth, or two thousand miles, is solid and rigid,
268 Reviews—Ansted’s Physical Geography.
readers are left to evolve theories for themselves as to our planet’s
condition when the, perhaps, altered rocks of the remote interior,
or even at a depth of two thousand miles, were, it may be, formed
at the surface.
Chapter third is geological, dealing with the succession of rocks
and metamorphosis, setting forth with regard to the latter that “it
is certainly by, and with water, that all essential change must be
traced...... Water has compacted the loose particles ; water has
opened large cavities; water has filled them with quartz and other
crystals ; and water has carried in the metals. A little heat would
have caused other combinations.”
To currents of heated water and electric currents all the trans-
formation and metamorphosis of the richest metalliferous rocks of
countries where mining is carried on in slate are attributed; while
nervous energy in the animal system is said to be represented in the
globe by currents of earth-magnetism mysteriously obtained from
the sun, and vital heat by the higher and equable temperature at
moderate depths. ;
In part the second, under the heading Earru, we have an able
but short summary of the distribution of the land, and its forms, its
mountain chains, hills and valleys, plateaux and low plains. This
portion of the work, the smallest but one, treats essentially of the
geography called physical, and is pregnant with matter so interest-
ing to the student of this science that its condensation will be re-
gretted though it consists mainly of statistics, so to speak, and
touches lightly upon theories relative to the causes which may have
governed or produced the present arrangement of the great physical
features of the globe. Denudation is said to have played an im-
portant part in all the phenomena of Switzerland and the Tyrol;
but its effect in forming the high detached mountains of the Alps
is not discussed, nor is its powerful agency in producing mountain
forms prominently put forward.
There are said to be valleys of fracture or fault, and valleys of
erosion,—mountain gorges being referred to the former, but no
examples given; and though it is not stated which are the most
frequent, all valleys are described as more or less distinctly valleys
of erosion.
From the part treating of low plains, we extract a passage refer-
ing to the Steppes of the south-east of Europe, which will warrant
the wish that we had more instances of such vivid description in
the volume :—
“Tn these Steppes the seasons are very strongly marked. In the spring and early
summer the land is carpeted by flowers. In the summer it becomes parched, after
yielding as food or hay a fair supply of mixed grasses, which may be stored for
winter use ; bat in the latter part of summer and autumn it is perfectly bare and
burnt up. In winter, which begins in October, the whole area becomes covered with
snow, and this remains until spring. There are no trees on those great plains, and no
enclosures of any kind; but at intervals the surface is broken by hollows scooped
out of the plain, to a depth varying generally from fifty to one hundred feet: and in
most of these are villages and some cultivation, especially on the borders of the plain,
and in the vicinity of the coast, or of the great rivers. ‘Ihere are, however, no roads,
and indeed there is no material for making them.
Reviews—Ansted’s Physical Geography. 269
One may travel for hundreds of miles over the level surface of the ground,—over
the turf in spring, through the thick dust in summer, and over the snow in winter—
without seeing a single object rising above the general surface of the plain. The
post-houses, at equal and distant intervals, are the only signs of humanity and civil-
ization; and the cry of the bustard is one of the few sounds that break the terrible
monotony and stillness. The dead -level of thin pasture, even if luxuriant, soon
fatigues the eye; and when the horses and cattle are away there is absolutely nothing
for the eye to rest upon. The travelling across the steppes, conducted with great
rapidity, in a kind of light cart, is thus not so difficult as it is tiresome; but it is
only safe in summer: and when the snows cover the ground, not only does it become
dangerous, from the wolves who take refuge in the hollows, but almost. impossible,
owing to the absence of land-marks. It is understood that an entire corps d'armée
was lost in the steppes, between the Dnieper and the Don, while attempting to rein-
force the Russian army in the Crimea, during the war with England and France.
Throughout the southern part of the steppes, and in much of the country to the
east, there is either a thin soil or no soil at all. This condition, however gives place
in the interior to a remarkable and extremely black soil, of extraordinary richness,
capable of yielding inexhaustible supplies of wheat without any artificial treatment,
or any agriculture except of the rudest kind.
These parts of the steppes now supply enormous quantities of corn to the great
markets of the world, and when opened, as they soon will be, much more completely
by railroads and steam navigation on the great rivers, it is certain that both Russia
and the rest of Kurope will be great gainers. A wide range of the plains is, however,
hopelessly barren, and all of them depend much on the occasional rains ; when these
fail the heat is excessive, and the sun rises and sets like a globe of fire, while during
the day a thick mist covers the earth. The drought soon becomes excessive; the
small supplies of water found at other seasons in the hollows fail altogether; the air
is filled with dust and impalpable powder, and the cattle and horses perish by
thousands.
In the winter the case is equally bad: fearful storms often sweep over the desolate
plains: the dry snow is driven by the gales with a violence which neither man nor
animal can resist; but the sky remains bright, and the sun shines cold and clear in
the blue vault of heaven. These storms are especially frequent in the vast Aralo-
Caspian plain, which is depressed below the general level of the sea, and which is to
a great extent an ocean of shifting sand.”
Oceans, riyers, lakes,.ice, and springs, receive a somewhat more
extended notice in part the third, under the heading Warrer. The
existence of organic life at the greatest ocean depths is shown from
the deposits there consisting largely of foraminifers which have
been found half-digested in the stomachs of living star-fishes brought
up from a depth of nearly two miles in the mid-Atlantic. The fact
of many lakes in both the old and new world having a depth
reaching below sea-level is stated; but slight allusion is made to
any connexion between the frequency of lakes and a former glacial
period ; the viscous theory of ice is not advocated, its progressive
movements being attributed to regelation; and thermal springs are
regarded as a kind of aqueous volcanos.
The fourth division of the book is headed Arr, and is eminently
meteorological, treating of the atmosphere, winds, dew, and climate ;
storms, trade-winds, cyclones, clouds, rain and rain-fall, magnetic
storms, etc.
Among many points of interest the difficulty of accounting for
why the heavier atoms of water in the form of clouds, which lose
their power of wetting at certain altitudes, remain “permanently in
contact with the lighter atoms of oxygen and nitrogen of the air ” is
noticed, and it is not thought necessary to assume that the water is
present in any other than its most ordinary condition.
270 Reviews— Banca and its Tin Stream-works.
Part fifth, Frrn, treats of volcanos and earthquakes; the account
of the distribution of the latter im space and time being chiefly taken
from Mr. Mallet’s report to the British Association, “‘ On the Facts
and Theory of Harthquake movements,” as stated in a foot-note.
Jn the last part, called Lirs, a connection is sought to be established
between organic existence and physical geography, through that
which exists between matter and motion, vital energy being taken to
be a form of force. This is considerably the largest sub-division of
the work; and however slight or profound the reasons may be con-
sidered which connect it with the subject of the book, the part is,
in itself, a comprehensive treatise upon the distribution of plants and
animals in different countries, and in time, with a concluding chapter
on the effects of human agency upon inanimate nature.
The length of this notice of a book in which so many important
subjects find places, has left little room for further comment. Its
teachings will serve to introduce the student to a wide field of
research ; and while it so well deserves a place in every library, no
one who reads at all should be ignorant of the various and numerous
interesting facts affecting the physical geography of our globe,
which are placed before him by Professor Ansted in so readable a
form.
II.— Banca Anp rts Trn Stream-works. By P. van Dies, Mining
Engineer. Translated from the Dutch, with the Author’s per-
mission, by C. Lz Nuys Fosrmr, B.A., D. Sc., ete. With Two
Geological Maps and Two Woodcuts in the text. 8vo. 85 pages.
Truro: Heard and Sons.
S it is possible that the name Banca will not be familiar to all
our readers, we will begin by saying that Banca is an island
between Sumatra and Borneo. It belongs to Holland, and for a long
period has been an important tin-producing country. The average
annual production of metal during the last fifteen years has been
more than 5000 tons, and consequently Cornwall has found Banca a
formidable rival in the tin trade. This has naturally caused a strong
desire in the county of Cornwall to know what the resources of
Banca are; how long Banca can go on producing tin at a sufficiently
low price to compete with England ; indeed; it has been seriously
proposed to send out a commission to investigate the resources of the
island. While much discussion was going on, Dr. Le Neve Foster
ascertained that Mr. P. van Diest, a mining engineer in the employ
of the Dutch Government, had written an account of his seven years’
stay in Banca, and it is a translation of this work which forms the
subject of the present review.
The first two chapters are beyond our province, as, to quote from:
the preface, they “make us familiar with the country, the inhabi-
tants, and the mode of working the stream-tin.” The remainder of
the work is largely devoted to a description of the geology of the
island, and as the work is accompanied by a chromo-lithographed
geological map of the northern half of the island (scale one inch to
eight miles) there is no difficulty in following the author’s descrip-
Reviews— Banca and its Tin Stream-works. Dik
tions, though it must be confessed that a few sections across the
country, no matter how rough, would have made the work more
complete.
The Island of Banca consists largely of clay-slate, and sandstone,
with intermediate varieties of rock. These rocks contain no fossils,
and Van Diest supposes that they are pre-Silurian; but as he relies
solely on the absence of fossils the opinion is not of very much value.
‘According to the author, these stratified rocks have been broken
through by granite, which has altered them into mica-slate, quartzite,
and other metamorphic rocks. Tin occurs in Banca in the solid
rock and also as stream tin. The former mode of occurrence is
summarized as follows :—
“1. In Northern Banca tin occurs in the granite in various ways
and over a large extent of country.
“2. The rocks which surround the granite are impregnated with
ores and other minerals occurring in®the granite for some distance,
usually not more than a mile and a quarter.
“3. These minerals and ores are chiefly deposited in little veins
or bunches in the direction of the planes of bedding or in the joints.
“4. Tt is chiefly the sandstone which has taken up these minerals,
especially where the rock appears to be the most metamorphosed.”
Van Diest comes to the conclusion that there are no veins of tin
ore or tin lodes in Banca which will pay for working.
With regard to the origin of the tin ore the author supposes that
the granite was once in a melted state, and contained tin “ equably
disseminated through it.” The granite near the sedimentary rocks
cooled quickly, and by its solidification prevented the escape of the
metallic particles, though not before some had found their way into
the surrounding rocks; where the granite cooled slowly the heavy
metallic particles sank down and were not fixed.
However simple this theory may be it is hardly quite satisfactory.
Every theory accounting for the formation of the tinstone in lodes
should at the same time explain the origin of the peculiar minerals
which accompany it so universally. Van Diest does not attempt
this, and one is tempted to suppose that he is not acquainted with
Daubrée’s masterly essays, where the whole subject of the origin of
tin deposits is fully dealt with.
The description of the mode of deposition of the stream-tin is clear
and worthy of attention. The author fully realises the effect of gra-
dual weathering and of rain. He does not, however, follow English
“subaérialists’” in supposing that the form of the ground is mainly
due to subaérial influences; for in a note (p. 67), after giving an
instance of rapid weathering which came under his notice, he says :
“From this it may be inferred that the hills when first formed were
very much higher and larger and the ravines deeper and steeper
then at present.” He explains thoroughly the occurrence all along
a valley of a bed of tin-ground, i.e. stanniferous gravel. It used to
be supposed that this bed had been formed all at once by sudden
floods or great rushes of water. The diagram (p. 70) shows very
plainly that this tinny gravel or tin-ground must not be looked upon
272 _ Reports and Proceedings.
as a deposit formed all at once, but, on the contrary, as a very gra-
dual one. Whilst tinny gravel was being deposited at the head of
the valley, fine silt was settling down at the lower end of the valley
ten or twenty feet above previously deposited tin-ground. The tin-
ground at the lower end of a valley may therefore have been de-
posited thousands of years before a similar deposit situated a mile or
two higher up. ;
There is next to nothing to interest the paleontologist. Remains .
of an elephant have been found in one place in Banca in the tin-
ground. At the present day the elephant is living in Sumatra but
not in Banca. The fossil, therefore, points to an ancient connection
between the two islands. The following summary is good :—
“J. The stream-tin of Banca is derived from the granite and the
rocks that surround it to a distance of nearly two miles.
“2. The valleys and tributaries’ which take their rise in these
rocks, and also the plains close by them, carry stream-tin; but the
valleys which are found elsewhere contain no tin.
“3. A deposit of tin derived from one source seldom extends further
than two miles along a valley.”
On the whole, the work forms a useful addition to our knowledge
of the geology of the Indian Archipelago, and persons interested in
tin will find plenty of details concerning the working and smelting
of the stream-tin of Banca.
Rn PORTS, AND PROC Hl DLlaN Gs:
wor
GrotocicaL Socirty or Lonpon. — April 17th, 1867.—Sir
Charles Lyell, Bart., M.A., F.R.S., Vice-President, in the chair.
The following communication was read. :—
“On the Physical Structure of North Devon, and on the Palzon-
tological Value of the Devonian Fossils.” By Robert Etheridge,
Esq., F.R.S.E., F.G.S., Palzeontologist to the Geological Survey of
Great Britain.
The Lower, Middle, and Upper groups of sandstones and shales
of West Somerset and North Devon were described in this paper as
occurring in a regular and unbroken succession from north to south ;
namely, from the sandstones comprising the promontory of the Fore-
land, at the base, to the grits and slates, etc., overlying the Upper
Old Red Sandstone of Pickwell Down to the South. The author was
unable to see any traces of a fault of sufficient magnitude to invert
the order of succession, or that would cause the rocks of the Fore-
land at Lynton to be upon the same horizon as those south of a line
of high ground that passes across the county from Morte Bay on the
west to Wiveliscombe on the east.
The Foreland grits and sandstones are overlain by the Lower or
Lynton slates, and form a group equal in time to the Lower Old
Red Sandstone of other districts, but deposited under purely marine
conditions.
1 There is evidently a word left out here. The sentence should doubtless stand
thus: ‘The valleys of rivers and their tributaries,” etc.
Leeports and Proceedings. 273
The author then showed that above the Lower or Lynton slates
there is an extensively developed series of red, claret-coloured, and
grey grits, from 1500 to 1800 feet thick; these form a natural and
conformable base to the Middle Devonian or Ilfracombe group. The
highest beds, containing Myalina and Natica, insensibly pass into
the gritty and calcareous slates of Combe Martin, Ilfracombe, ete. ;
this Middle group Mr. Etheridge unhesitatingly regarded as the
equivalent of the Torquay and Newton Bushel series of South Devon.
Mr. Htheridge gave detailed Tables of the organic remains of the
two groups (the Lower, or Lynton, and the Middle, or Ilfracombe),
and collated to them those species found in equivalent strata in
Rhenish Prussia, Belgium, and France. He was inclined to believe
that these two marine fossiliferous groups represent in time the
unfossiliferous Old Red Sandstone (Dingle beds) of Kerry, and the
Glengariff and Killarney grits of the south-west of Ireland.
The author then endeavoured to prove that the Pickwell Down
beds are the true Upper Old Red Sandstone only, not the whole of
the formation, as was lately proposed.
Arguments were also brought forward to show the probability of
the Carboniferous slate (in part) and Coomhola grits being the
equivalent of the English Upper Old Red Sandstone, or Upper
Devonian, and that the North Devon beds only are to be regarded
as the true type, to which the Irish must be compared, and not vice
versd. '
Physical and Paleontological evidence distinctly proves, the
author states, that the whole of the slates and limestones of Lee, Il-
fracombe, and Combe Martin underlie the Morte Bay red sandstone.
The author compared the whole of the Devonian fauna of Britain
with that of the Rhine, Belgium, and France, by means of a series
of tables based upon the British types. These marine Devonian
species were compared with those of the Old Red Sandstone proper,
the Silurian and Carboniferous, and analyses were made of all the
classes, orders, genera, and species, with relation to the groups of
rocks in which they occur—the result being the conclusion that the
marine Devonian series, as a whole, constitutes an important and
definite system.
Tue Grouocican Socrnty or Guascow.—The concluding meeting
of the present session of this Society was held in their room in
Anderson’s University on Thursday evening, the 18th of April.—
Professor Young, President, in the chair. The following papers
were read :—
1. “On the Entomostraca of the Carboniferous Rocks of Scotland.”
By Professor T. Rupert Jones and Mr. James W. Kirkby, Honorary
Members of the Society.
The observations of the authors had reference only to the Bivalved
Entomostraca of the Ostracodous and Phyllopodous groups, of which
Cypris and Limnadia are the recent types. Upwards of seventy
years ago the Rev. David Ure figured and described four species of
these little Bivalved Crustacea from the Carboniferous Limestone of
VOL. IV.—NO, XXXVI. 18
274 Reports and Proceedings.
East Kilbride. The discovery of these species by Ure bore evidence
to his close powers of observation, and in this respect he compared
favourably with many who had followed him in the path of palon-
tological research. With the exception of Hibbert, who described
two species from the limestone of Burdichouse, this group of fossils
remained unnoticed in Scotland, until the subject was taken up by
some of the members of the Society within the last few years; and
to their very close researches the authors have been largely indebted
—the list now embracing upwards of fifty species. The leading
features of the various genera—Cythere, Bairdia, Leperditia, Beyri-
chia, and Kirkbya—were then sketched, and Tables exhibited, show-
ing their range in the Carboniferous strata of Clydesdale. An
examination of these Tables showed that, with a few exceptions, all
the species had been found in the Lower Limestone Series of that
district. Several of them do not extend beyond the limits of that
division, though the majority range into the Upper Limestone; and
only four are known to occur in the shales and ironstones of the
Upper Coal Series. It was interesting thus to notice this group of
species in their life-history in the Carboniferous era. Their appear-
ance and dying out was not a regular unbroken process; nor did
they all appear to have ever existed in one area at any one period of
time, notwithstanding their presence in nearly all the beds of one
series. For example, in a limestone or calcareous shale, with marine
fossils, certain species of the above-named genera were generally
found. Above these strata might be either arenaceous rocks or alum-
shales, in which these species were absent. The next stratum might
be one of those termed ‘freshwater limestone,” containing Fish
remains, Spirorbis, and vegetable fossils. The Hntomostraca in this
bed might be three or four Cytheres, of species different from those in
the first-named deposits. Higher in the series occurs another bed of
shale, containing marine fossils, and with them all, or most of the
Bairdie, some Beyrichie, that had occurred before, with, perhaps,
one or two forms to take the place of others that had not returned.
The species all vanish again with the second bed of shale; and
probably the next occurrence of Entomostraca would be considerably
higher up, when one of the Cytheres of the “freshwater limestone”
would return, and abound alone in a single thin stratum. This
interchange of species continued time after time; not, perhaps,
always to the same extent, but always with some variation in the
distribution. Nevertheless, there is considerable persistence in many
of the species that return at different intervals—the same groups of
species appearing and re-appearing many times without any essential
change in their constitution. They always, moreover, re-appeared
under exactly the same condition. Several examples of this were
quoted. The authors concluded their valuable communication by
discussing the physical conditions which had prevailed during the
deposition of the Carboniferous series of rocks in Scotland.
To illustrate the paper, Mr. John Young exhibited his interesting
collection of mounted specimens of Entomostraca from the Carboni-
ferous Limestones and Shales of the West of Scotland.
Reports and Proceedings. 270
2. “On the Change in the Obliquity of the Ecliptic: its Influence
on the Climate of the Polar Regions and Level of the Sea.” By Mr.
James Croll. The reading of this long and valuable communication,
which will be published in full in the next part of the “Society’s
Transactions,” was followed by some observations by the President
and the Rev. H. W. Crosskey.
Dr. Young exhibited a new Crustacean from the Upper Silurian
Rocks of Lesmahagow, which had been kindly lent him by Dr.
Shimon. He believed that it belonged to the genus Hemiaspis, which
Mr. Woodward is at present studying. The specimen is interesting
as being the first which has occurred in the Lesmahagow district.
Mr. James Thomson then exhibited a new genus of Carboniferous
Corals, of which beautiful photographs of polished sections were
shown by the oxyhydrogen light.
Before declaring the session closed, the President congratulated
the Society on the number of important papers which had been read
during the winter, and on the wide range of subjects which had
engaged the attention of members. The Society, since it was founded,
had cautiously abstained from rash generalisations; it had, on the
contrary, devoted itself to the careful observation of facts; and it had
at once rendered the best service to science, and earned for itself a
distinctive character by the ready generosity with which its accu-
mulated results in physical geology and paleontology had been
placed at the disposal of those who were engaged in special studies.
The Transactions of the Society contain the testimony of Davidson,
Woodward, Kirkby, and Rupert Jones, to the success and the liberality
of Glasgow collectors; while the records of other Societies often
show that not a few contributions have been founded on materials
derived from the West of Scotland. The only purely theoretical
paper of the session, that by Mr. Croll, “On the Influence of the
Obliquity of the Hcliptic,” had been read this evening. Discussion
on such an admirable and exhaustive memoir is impossible ; but the
Society may well be proud that such a memoir will be found in its
publications. On questions of physical geology, Messrs. Dougall,
Skipsey, J. Bryce, LL.D., Bennie, J. Young, and J. Young, M.D.,
had contributed papers referrmg to the Southern Highlands, the
Rocks of Ayrshire, of the Kilpatricks, Arran, and of the vicinity of
Glasgow. In chemical geology, Mr. J. Wallace Young has from
time to time given us the results of his analysis of rocks from the
Carboniferous strata, and brought into notice some remarkable pecu-
liarities in their composition. The paleontological contributions
come under three groups—lIst, The faunas of different periods have
been illustrated by the Rev. H. W. Crosskey in the case of the
Glacial beds; by Mr, Young in that of our Limestones; by Mr.
Dairn in that of the Southern Silurians. 2nd. Descriptions of species
and of genera have been given incidentally at nearly all the meet-
ings, and have formed the subject of two very important papers—
that by Mr. H.Woodward, and that read this evening by Messrs. Jones
and Kirkby. 38rd. At every meeting specimens have been shown
from the human remains of the Clyde alluvium to the earliest Silu-
276 Maw—Drift Deposits of the Eastern Counties.
rian fossils. The ranges of some species have been shown to be
more extended than was formerly supposed, and for others new
localities have been announced. The admirably prepared corals of
Mr. James Thomson have further indicated, as was seen this evening,
that nature-printing can be applied with success in the representa-
tion of fossils, and that the lantern can be used to make clear the
minutize of structure. The enumeration of problems in Scottish
geology at the opening of the session was a well-timed reminder of
what remains yet to be done. It is from no disregard of Mr. Page’s
advice that none of the difficulties he spoke of have been attacked ;
it only shows that there is a very wide field to go over before the
materials for the higher generalisations, such as he alluded to, can
be amassed. In conclusion, the President expressed his conviction
that the labours of members during the summer would render next
winter’s session at least as fruitful of instruction as that which had
now drawn to a close.
The Society then adjourned till the first Thursday in October.—J. A.
CORRESPONDENCE.
THE DRIFT DEPOSITS OF THE EASTERN COUNTIES.
To the Editor of the GrotocicaL Macazinn.
Dear Srr.—The communications from Mr. Hull and Mr. Searles
Wood, junr., in the April number of the Magazine, called forth by
my remarks on the relative ages of the Boulder-clays of the Hastern
Counties, seem to invite a few further observations from me. I wish,
in the first place, to state that the object of my paper in the March
number of the Magazine was rather to show that an order of sequence
of the coast and high-level clays, fitting in with Mr. Dawkins’ views
of the Thames valley deposits, was as probable as that supported
by Mr. Wood, than that the evidence was absolutely conclusive as to
the order of succession I suggested.
The individual members of the Glacial series contain scarcely any
distinctive characters based on organic remains, and the constantly
recurring local variations of their mineral character seems to render
it almost hopeless to attempt any general classification on mere
lithological evidence. This makes me view with less confidence
. than Mr. Wood the means of identification by which it is attempted
to connect, in distant localities, the various subordinate members of
the Drift series. With reference to the superposition of the Boulder-
clay of High Suffolk on that of the Norfolk coast; im the absence of
an unbroken section, there seems to be scarcely sufficient available
proof either that the green clay referred to by Mr. Wood is the
equivalent of the Cromer Boulder-clay, or of the red loam south of
Norwich; or, again, that there is an unquestionable identification
between this red loam and the red sand which underlies the beds in
the lower part of Dunwich cliffs, assumed by Mr. Wood to be the
Maw—Drift Deposits of the Eastern Counties. 277
equivalents of his Middle drift. Moreover, this Middle drift is
nothing but a mass of sand and gravel of constantly varying
character, and having by itself no distinctive aspect.
I wish to explain that in referring to the general uniform altitude
of the bed I termed “high-level Boulder-clay” (Mr. Wood’s Upper
drift), I did not suppose that this was any distinctive test of its age,
as the original irregular basement line upon which it was deposited
would to a certain extent determine its altitude; indeed, there are,
I believe, several isolated patches in the neighbourhood of Tunstall,
Chillesford, etc:, at a much lower level than the general mass forming
the higher ground of Suffolk; but whilst a deposit having a great
range of altitude may extend down to any point towards the sea-
level, a uniform limitation of height (which is, I believe, the case
with most of the Boulder-clays on the coast-line) may result from
having been deposited by an agency that never attained beyond a
certain level, and may therefore, in one sense, be taken as a distinctive
test of age.
The clay which extends so widely over High Suffolk to an altitude
of from two hundred to three hundred feet above the sea, never
attains anything like this height in any coast section, and as you
descend from the flat table-land it appears to be abruptly cut off by
the general denudation-contour of the country.
The general level of the Chalk-surface in Suffolk is from eighty to
one hundred feet above the sea, and on Mr. Wood’s classification his
Lower drift occurring on the coast, would have formed with the
Chalk a tolerably level basement line for the future superposition of
his Middle and Upper drifts.. How is it, then, that the clay on the
high ground of Suffolk, which is so uniform in level and mass for
many miles inland, disappears (or, on Mr. Wood’s view, becomes
attenuated) asthe lower ground is reached? I believe it is only to
be accounted for by the denudation of the clay on the higher level
previous to the deposition, as a sort of fringing terrace, of that on
the coast, which throughout the whole circuit of the country never,
on the coast, attains the height of the inland drifts. If it is a mere
extension, coastwise, of the drifts occurring at higher levels, the
lower level of the base at the coast on which it was deposited would
account for it; but the coast Boulder-clay and drifts frequently occur
where the higher ground, as you recede from the sea, is driftless.
Tf this coast-clay is as Mr. Wood supposes, a more ancient deposit
than the higher drifts occurring inland, it seems difficult to account
for the higher drifts which were deposited within: a few miles inland
on the Chalk, not being also superimposed on the coast-drifts—the
surface of which would have formed a foundation of about the same
height as the inland Chalk.
Again, if it is assumed that the high-level Boulder-clay and
subjacent gravel-beds (Mr. Wood’s Upper and Middle drifts) form
a portion of the cliffs on the Norfolk coast, descending towards the
coast on a sloping base line, why should they become so attenuated in
mass as in no instance to attain, with Mr. Wood’s Lower drift, a
collective thickness greater than that without the so-called Lower
278 Maw—Drift Deposits of the Eastern Counties.
drift on the higher ground? as the attenuation of its mass would be
likely to take place where the fundamental base was highest.
The following section (for which I am indebted to Mr. Rose, of
Great Yarmouth) of Corton cliff, between Yarmouth and Lowestoft,
is one of the cases cited by Mr. Wood as an example of the supposed
occurrence of his “Upper” and “Middle drifts,’ superimposed on
his “ Lower drifts.”
The cliff is from thirty to fifty feet high, and consists of the
following beds :—
a. Vegetable soil.
b. Warp of Mr. Trimmer, and ‘‘ Upper drift ’’ of Mr. Rose.
c. Boulder-clay, three to nine, or twelve feet thick. Boulders abundant, and varying
from a few pounds to several tons in weight. Color of the clay various, occur-
ing in extensive patches of blue, drab, and yellow.
d. Sand having in places false stratification, with shingle at its lowest portion
fifteen to, twenty feet thick.
e. Loamy clay, uniform in colour. Erratics small and scarce.
The bed c is, I presume, that which Mr. Wood would correlate
with his Upper, and d with his Middle drift. From what I have
seen of the cliffs south of Cromer, J must demur to the opinion that
there is anything like a uniform succession of the beds for any
distance along this coast. As a general rule, tough Boulder-clays
occur towards the base of the cliffs, and sand, gravel, and silty beds,
more or less contorted in its upper parts; but beyond this there is
nothing like uniformity, and various sections could be described that
it would be impossible to trace any kind of resemblance in, to that
given above. Sand, gravel, Boulder-clay, and silt-beds interlace in
endless variety, and I must take exception to an occasional resem-
blance in the order of superposition of the clays and sands along
this coast, being adduced in support of their being the equivalents
of the Boulder-clay and its underlying gravel bed, covering the
higher ground of Suffolk.
The very variety of these coast-beds seem to distinguish them
from the ‘clay of High Suffolk: the high-level clay is generally
uniform in color, and the materials smaller, and more even in size
than in that of the coast, and it is seldom interstratified with sand
beds. I have not seen the Corton Cliff section, but from Mr. Rose’s
description, J should judge that the series of beds there super-
imposed bears little resemblance to the High-Suffolk drifts. -
Mr. Hull suggests a relationship between the order of sequence
laid down by Mr. Wood for the Eastern Counties, and the drift
series in the neighbourhood of Manchester, expressing a hope that
the drift question may be simplified by Mr. Wood’s classification be-
ing found applicable to both sides of the Island. I fear the test of
facts will scarcely support so simple a classification as the sub-
division of the whole Glacial series into upper and lower Boulder-
clays, separated by a mass of sands and gravels. Such a uniformity
over so great an area would be highly improbable, and scarcely
consistent with the lithological changes observable within much
smaller areas in the other Tertiary strata; furthermore, it seems to
reduce the whole Drift era into one uniform progressive accumula-
Maw—Drift Deposits of the Eastern Counties. 279
tion, and to ignore those complications of arrangement which might
result from repeated periods of submergence, and the fresh distri-
bution and reformation of the materials composing the earlier
deposits. There are two obvious difficulties in the way of working
out a uniform sequence on lithological evidence. 1st. The constantly
varying character of each individual bed, clays and sands passing
into each other, through gradations of clayey sand and sandy clay,
which, unless you have an absolute continuity of section, renders
certain identification impossible. 2nd. That after the coast line is
left, the various levels at which the same bed may occur (following
an irregular basement line, as pointed out by Mr. Hull, in his paper
on the Manchester drifts), complicates the difficulty, rendering it
impossible to pronounce with certainty to which division an isolated
mass may belong.
The following particulars of a few drift sections with their range
of altitude above the sea, will illustrate the extreme difficulty of
identifying the individual sub-divisions in distant localities—
Strethill, near Ironbridge, Severn Valley.—F rom 100 to 310 feet above sea; 210
feet thick. A stratified hill of drift, consisting of 70 feet of sand and gravel at
its base, 70 feet of Boulder-clay, and capped by a further bed of sand and gravel
70 feet thick.
Buildwas, near Tronbridge, Severn Valley.—From 100 to 270 feet above sea, and
a range of altitude of 170 feet. Within about a mile of Strethill, on the opposite
side of the Severn Valley. Sands and gravels lying against the sloping side of the
valley. No distinct bed of Boulder-clay.
Bridgnorth.— St. James’ Gravel Pit, Severn Valley.—Eight miles below Strethill.
70 to 250 feet above sea level, and range of altitude of 180 feet. Terraces of gravel
and shingle, with no distinct Boulder-clay. At Quat, two miles lower down the
valley, the drift is almost wholly made up of the detritus of Bunter Sandstone, and
in the cuttings of the Severn Valley Railway, at the same level on the west side of
the valley, the drifts consist of loamy gravel of constantly varying character.
Ryden Hill, Benthall, Shropshire-—From 530 to 600 feet above the sea; range of
altitude and thickness 70 feet. An isolated knoll of clean sand and fine gravel.
Gravel-hole, Willey Park, near Broseley.—350 to 400 feet above sea; range of
altitude, 50 feet, sand and gravel.
Burton, near Much Wenloch.—750 to 800 feet above sea; range of altitude about
50 feet. Loamy sand and gravel, with transported boulders, but no tenacious
Boulder-clay.
Middletown Railway Station, Montgomeryshire.—Cutting west of station, 310 to
530 feet above sea; thickness 120 feet, consisting of 65 feet of tough clay, overlain by
45 feet of gravel and pebble beds, intermixed with clay and boulders.
Crowfield, near Coddenham, Suffolk.—From 100 to 200 feet above sea, thickness
100 feet, consisting of about 45 feet of sand and gravels, resting on the Chalk ; over-
lain by 55 feet of tough Boulder-clay.
Moel Tryfan, Carnarvonshire.—Alexandra Slate Quarries.—1270 to 1320 feet
above sea, range of altitude 50 feet, consisting of from 20 to 30 feet of clean sand
and gravel beds, containing shells, overlain by from 6 to 15 feet of Boulder-clay,
containing transported stones or boulders. some of large size.
Moel Tryfan, Carnarvonshire (foot of the hill).—From 500 to 600 feet above sea-
level, range of altitude about 150 feet. Boulder-clay skirting the base of the hill, of
similar character to that near its summit.
This list of examples might be extended ad infinitum, but will
suffice to show the extreme difficulty of distinguishing on any
certain basis, and identifying in distant localities on mere litho-
logical character, the individual subdivisions of the Drift series.
If compared with the sections, enumerated by Mr. Hull in his
280 Mauw—Drift Deposits of the Eastern Counties.
memoir on the drift deposits of the neighbourhood of Manchester,
it will be seen that the correlation of the individual subdivisions is
utterly hopeless. If, for example, the Strethill Severn Valley
Section, where there is the unusual consecutive thickness of 210
feet, is compared with the full series given by Mr. Hull in the
neighbourhood of Manchester, it will be found that there is no
possible correspondence in lithological subdivisions. At Strethill
there is but one Boulder-clay separating two masses of gravel, and
in the Manchester district one sand and gravel bed intervening
between an upper and lower Boulder-clay. Both series seem to
have about the same range with reference to sea level, but to bring
them into possible correspondence as to lithological subdivision, it
must be assumed, not only that one of the Manchester Boulder-
clays is absent in the Severn Valley, but that one of the Severn
Valley gravel beds is missing at Manchester. These changes will,
however, be more easily explained by recognising the extreme local
character of the great mass of the materials making up the drifts,
and consequently the continual variation of their lithological condi-
tion, depending on the sources of materials and the local circumstances
of surface contour under which each was deposited.
The extreme uniformity in the mineral .character of the higher
Boulder-clay of the Eastern Counties is remarkable, and contrasts
with the varying composition of the drifts in other parts of the
kingdom. The fact that there is nowhere to be found, on the imme-
diate coast, such a thickness of drift as frequently occurs on the
higher ground, seems to render it probable that the comparatively
uniform terrace of clay, fringing the coast, was deposited during a
limited submergence, when the coast outline differed little from
what it is at present. If the coast clays and drifts are merely a
seaward prolongation of those occurring at much higher levels
inland, it seems difficult to account for its never capping the coast
cliffs of the older formations that exceed 200 feet in height, and if it
is the same drift on the coast that rises within a few miles (as for
example on Moel Tryfan) to more than 1000 feet, it would be ex-
pected to rise over the older formations on the coast cliff line, and
if the coast clay is older than the drift on the higher ground, how is
it that the higher is not superimposed on the lower, forming a
collective mass somewhat approaching the height of the inland drifts
superimposed on the older formations? Another point to be
noticed is, that the fringing terrace of clay is often present (as for
example on the Yorkshire Coast) along the coast where the adjacent
higher ground is driftless. In connection with this point may be
noticed the occurrence of erratic boulders at Pagham and along the
coast, west of Bognor, Sussex, the ground a little above the coast
line being entirely without drift; indeed, nearly the whole coast
circuit affords evidence of this limited submergence. The driftless
area of Devonshire is on the south coast fringed with gravels, which
seldom reach more than 150 feet above the sea, and on the north the
great deposit of clay and an underlying gravel bed, near Fremington
and Barnstaple, betokens a similar limited amount of submergence.
Maw—Drift Deposits of the Eastern Counties. 281
The general absence of drift at a high level on the coast—as, for
example, on the top of high coast cliffs—can only be accounted for
by its having been denuded previously to the deposition of the
fringing terrace of low level clay and drift, and of this there seems
good evidence, as the contour of much of the higher drift partakes
of the general denudation contour of the older rocks, implying a de-
position previous to the excavation of some important river-valleys,
and to the existence of the present surface contour.
Gzorce Maw.
BrentHatt Hawt, BrosELEY,
April 12th, 1867.
Note.—Since the above was written Mr. Fisher’s article “on the
Ages of the Trail and Warp” has appeared in the Magazine. As I
have had but little opportunity of examining the deposit designated
by Mr. Fisher as “Trail,” I must defer to his opinion that it is
identical with what Mr. Dawkins considered to be a Glacial deposit
overlying the Brick-earths of the Thames valley ; at the same time
if it is a subaérial deposit, arranged by the action of land-ice, it does
not seem improbable that it may be the equivalent in time of the
coast Boulder-clay.
If Ivightly understood Mr. Dawkins’ observations in the discussion
on his paper, he seemed rather to consider the supposed Glacial
deposits of the Thames valley as a submarine than a subaérial
formation. Under any view, the facts brought forward by Mr. Fisher
seem consistent with a long interval between the deposition of the
Boulder-clay on the higher ground of the east of England, and that
of the supposed Glacial beds of the Thames valley. As the high-
level Boulder-clay is intersected by the present valley system, whilst
Mr. Fisher’s “Trail” follows its denudation contour, I believe
there is evidence that the Till of the Norfolk coast was also deposited
after the Boulder-clay of the high ground had been considerably
denuded.
The deposit in the valley of the Yare, described as “a Third
Boulder-clay,” in Mr. Harmer’s paper, just published in No. 90 of
the Quarterly Journal, appears to occupy a similar position to that
which I believe the coast clay of Cromer, Mundsley, etc., bears in
relation to the Chalk, Crag, and High-level Boulder-clay, and may
merely be an inland extension of the beds on the coast, deposited
after the land surface received its present denudation contour.
Similar beds of Brick-earth to that numbered 5 in Mr. Harmer’s
section, occur interstratified with the bed of gravel (Mr. Wood’s
Middle Drift), underlying the Boulder-clay of High Suffolk, and its
identification with the coast clay seems to me scarcely supported by
sufficient proof.—G.M.
ON THE PARALLELISM OF THE DRIFT DEPOSITS IN LANCA-
SHIRE AND NORFOLK,
To the Editor of the GrotocicaL MAGAzINE.
S1r,—Mr. Hull has very faithfully drawn, although in somewhat
rough outlines, a parallel between the Drift deposits in Lancashire
282 Taylor—Drift of Lancashire and Norfolk.
(with which he is so well acquainted) and those in the Hastern
Counties... I do not known whether Mr. Hull has ever visited
Norfolk, or whether he has been guided by Mr. Wood’s description
alone. I have had the privilege of studying the deposits in both
districts, and can testify to the surprising parallelism which obtains
between them. The differences are even such as we should have ex-
pected, a priori, to result from local causes, and, instead of detracting
from the general resemblance, rather corroborate the opinion that the
deposits in both districts were formed under analogous circumstances.
Mr. Searles Wood’s outline of Norfolk Drift is correct. We have
the three great divisions of Lower, Middle, and Upper Drift—the
last but one consisting of mingled sand and gravel. These are the
broad features which distinguish the Drift deposits of the North.
The principal distinction between the two is that those of the North
are considerably thicker than those in the Hast. True, the Lower
Boulder-clay along the coast attains a great thickness, but it is some-
what singular that it should so rarely be found inland, and then
only in bands of a few feet thick. Whether this has resulted from
the thinning out or denudation of this deposit in a south-westerly
direction or not, I cannot say. The coast Boulder-clay has been
formed principally by the wreck and denudation of the Lias,? inso-
much that it obtains its blue colour from that circumstance, and liter-
ally teems with the re-deposited shells of the Lias, such as Gryphea
and Ammonites. Its great thickness along the coast, and its thinning
inland, would argue that it formerly extended in the North-east, over
what is now the German Ocean. The boulders are of Scandinavian
rocks in almost every instance. It is more argillaceous, and con-
sequently resembles its relative in Lancashire much more than the
Upper Boulder-clay does. In Lancashire it is largely developed,
and is extensively used for making bricks. Its almost entire absence
inland in Norfolk, therefore, prohibits any such application.
As regards the Middle Drift in Norfolk, it resembles that in the
North more than either of the other two members. Like its northern
representative, it is found in alternate layers of gravel and fine or
coarse sand, is often false bedded, and the pebbles are much water-
worn. These are singularly enough composed of granite, quartz, and
trap, as the same bed in Lancashire, and I have even detected
portions of the silicious grit known there as the “‘Gannister rock.”
The shells found in the Middle Drift of Norfolk complete the re-
semblance. At Stoke and Saxlingham (within ten miles of Norwich)
I have found Turritella communis—a shell which I myself found in a
similar position in the Middle Drift sands at Reddish and Hyde, in
Lancashire; as well as in the sands at Crewe, in Cheshire. Other
shells, many of them fragmentary, were also of similar species in
both localities.
The Upper Drift or Boulder-clay of Norfolk differs from that of
Lancashire more than any of the other divisions. The boulders of
primary rocks are not near so abundant as they are in the North. In
fact they are generally Oolitic, or flint nodules little worn down.
1 See Gzoxu. Maa. Vol. IV., April, 1867, p. 183. # And Kimmeridge Clay ?—Eprr.
Taylor—Drift of Lancashire and Norfolk. 283
All seem to have come from a less distance than those of Lancashire.
Mr. Hull gives the percentage (as determined by Professor Ramsay)
of rock fragments found in the Upper Boulder-clay at Gorton, in
Lancashire, as follows (vide Geol. of Country around Oldham: Memoirs
of Geological Survey) :
per cent. per cent.
SulErAM Grits. do caw Od. Granitews.. kre st ee
Felspar Porphyry ... 31 Porphyritic Conglomerate 4
Felstone Pale eco sieapese 2 Carboniferous Limestone 3
Carboniferous Grits ... 14 Ironstone RSS, Sas Ce a
In this case the Silurian Grits, which are most abundant in the
Upper Boulder-clay of Lancashire, may be taken to represent their
having been conveyed from a distance (the Silurians of Cumberland
and north of Lancashire) equivalent to the distance of the source of the
Oolitic pebbles found in the Upper Boulder-clay of Norfolk (the
Oolite of Yorkshire). The greater percentage of igneous boulders
found in the Lancashire Drift beds may arise from the fact of their
being nearer to their parent rock than those of the corresponding
beds in Norfolk. The small percentage of boulders of local rock
(sandstone) in Lancashire, as compared with the much greater per-
centage of flint boulders in Norfolk, may arise from the different
nature of the two parent beds whence both were derived. It would
be much easier for marine or glacial agency to disintegrate the Chalk
and liberate the enclosed flint nodules, than it would be to break up a
sandstone bed and to roll the fragments into boulders. But these
exceptions seem to me to carry out the analogy between the northern
and eastern deposits instead of detracting from their relation.
Mr. Binney very justly remarks’ on the varying nature of the beds
which compose the various members of the Drift or Quaternary
formation. The same feature is, more or less, common in Norfolk,
although it is not so decidedly shown as in Lancashire, owing to the
absence of high hills, along whose base, in the North, the various
drift beds usually split up into almost unrecognisable portions. At
Sprowston in Norfolk, in the Upper Boulder-clay, there are thin seams
of sand intercalated, in which Mr. T. G. Bayfield and myself found
numerous fragments of marine shells, among others of Cyprina
Islandica and Astarte borealis. But both in Lancashire and in Norfolk
these local deposits do not affect the general features of resemblance
so broadly manifested in both districts.
I remain, etc.,
Joun EH. Tavyzor.
Norwicu, May 8th, 1867.
BALA AND HIRNANT LIMESTONES AT MYNYD FRON FRYS IN
GLYN CEIRIOG.
To the Editor of the Grotogicat MaGazine.
Dear S1r,—I am glad to find Mr. Salter calling attention in this
month’s Magazine to one of the most interesting spots in North
Wales—especially so to students of the Lower Silurian group.
1 See Gzou, Maa. Vol. IV., May, 1867, p. 2381.
284 Davies—On Glyn Ceiriog.
As some of the features of this district (which Mr. Salter properly
suggests, are deserving the attention of Geologists), have already
had some attention paid them by myself, you will, perhaps, allow
me to say that, in 1859,1 I described the various beds of which this
hill is made up, noticing some of their peculiarities and rarer fossils.
In 1868, in a paper of mine on “The Bala Limestone of North
Wales and its associated beds,?” I classed the Upper Limestone of
the hill as “‘ Hirmant Limestone,” as Mr. Salter now proposes.
In a section which accompanied that paper; I represented the over-
lying schists “‘ Pale shales very fossiliferous,” as I called them (the
No. 5 of Mr. Salter’s letter) as conformable to the underlying beds.
In a letter which I afterwards received from Professor Sedgwick,
that gentleman—the value of whose labours in North Wales I esti-
mate very highly—said, “the order of superposition is quite clear,
yet there is, I believe, a break in the order of succession; and he
adds I should be grateful to you for more information respecting the
group of “pale shales very fossiliferous.” These remarks led me
to review the matter, and the result was that I found the “pale
shales of the Pentre hill and round about, to be unconformable to the
Bala group below, as Mr. Salter now wagers that, upon examination,
they will be found to be; and if your readers will refer to the Guo-
LoGicaL Macazine for 1865, page 344, they will find, in a section of
the beds referred to, that I have named the uppermost band of lime-
stone, ‘‘ Hirnant Limestone ;” and that I have represented these pale
shales of the Pentre as unconformable to those below.
Mr. Salter truly says, that working this district is like working a
museum ; and J may mention, in addition to the fossils he enumerates,
a beautiful one once examined and named by himself Ischadites tessel-
latus, which I quite expected to see in the excellent plates of fossils
that adorn Professor Ramsay’s admirable memoir on North Wales.
Plenty yet remains to be done there, and I promise any geologists
who may be willing to hammer for a day or two about Mynyd Fron
Frys, a charming time of it. If gentlemen, who would like a joint
meeting for the purpose of more fully exploring the spot, will com-
municate with me, I shall be glad to make the necessary local ar-
rangements, and to join them on the occasion.
I am, Sir, yours very truly,
D. C. Davins.
ConzEY-GREEN House, OswEsTRY,
May 3rd, 1867.
FISH IN DEVONIAN ROCKS,
To the Editor of the Grotocican MaGazine.
Str,—Can you favour me with space for a few friendly remarks
on the P.S. of Mr. Salter’s letter in your May number.
The fish defence spines in my collection are two in number,—
one from Looe Island, and one from Looe; not both “from the
1 Vide Proceedings of the Oswestry Field-club, pages 32-35. ® Ibid., page 71.
_ See also for section, Proceedings of the Liverpool Geological Society, 1863-4; for
list of fossils, ibid., 1864-5,
Brodie—On Fossil Insects. 285
island.” It will be found, by turning over the Reports of the Brit.
Assoc., the Trans. Roy. Geol. Soc. of Cornwall, and the “Geologist,”
that my “valuable data’ have not been ‘“‘long buried.” Will Mr.
Salter be so good as to say what is the evidence that “near Teign-
mouth we have the Upper Devonian beds?” I have no doubt that
his reply will be that pebbles containing Clymeniz are abundant in the
Triassic Conglomerate at Shaldon, near Teignmouth, and that the
Upper or Clymenia limestone must have existed close by. This,
however, if admissible, would be evidence of not what 7s, but what
was. But is it admissible? The Clymenie are found only in well-
rounded pebbles, which have clearly travelled long—perhaps far;
whilst the ordinary materials are but sub-angular, and are of imme-
diate derivation. ‘The Chesil beach at Portland contains, it is said,
pebbles from the Torbay limestones. They must have travelled at
least thirty-five miles, more likely double that distance, since, in all
probability, they followed the sinuosities of the coast; a fact which
suggests caution in drawing inferences from pebbles respecting the
whereabouts of their parents.—I am, etc. Wu. PENGELLY.
Torquay, May 2, 1867.
FOSSIL INSECTS IN THE CARBONIFEROUS ROCKS,
To the Editor of the GrotogicaL MAGAZINE.
Drar Srr,—I see in the March number of the GroLogicaL
Macazine that you mention the occurrence of the “Xylobius Sigil-
lavig ?” in the Upper Coal Measures at Kilmaurs, in Scotland; and
in the same number Mr. Binney records the discovery of the same
myriapod in the Lower Coal Measures near Huddersfield, and also
the remains of a supposed Coleopterous insect. Now as the German
and Belgian Carboniferous formations, especially the latter, and the
American Coal fields have yielded in places numerous insects, and
our own occasionally, I have very little doubt that a more careful
search would largely increase the number; and I hope the many
zealous collectors in our Coal-districts will keep a sharp look-out for
any Annulosa which they may fairly expect to find associated with
the plants in the shales and ironstones, especially in the latter,
where they usually occur. The fine Curculionideous beetle in iron-
stone from Coalbroke Dale, and the scorpion from Cholme in Bohemia,
long since figured and described by Buckland in the Bridgewater
Treatise, are well known. There is also a fine wing of a “Corydalis”
in the British Museum, from the same locality, figured and referred
to in Murchison’s “Siluria.” I have in my collection a wing of a
gigantic Neuropterous insect, in ironstone from the Derbyshire
Coal Measures. Professor Dana, in the “ American Journal of
Science” (vol. xxxvii. January, 1864), describes and figures a re-
markable fossil insect nearly entire, which he states to be like the
Semblids among the Neuropters, and especially the Chauliodes, and a
mutilated wing of another Neuropter, which approximates to the
genus Hemerobius. Both these specimens were discovered by Mr. J.
G. Bronson in the Carboniferous beds at Morris, Illinois. Sir
286 Harkness—Fossils of the Upper Llandovery.
C. Lyell refers to the presence of wings of Blatta and Acridites in
the coal in Westphalia, and to a still larger series of insect remains
in the ironstone near Treves, among which are several Blattide, Neu-
roptera, Termites, one Scarabeus, and the wing of a large Gryllus
which he figures under the name of “ Gryllacris lithanthrace ”
(Manual of Geology, sixth edition). The presence of spiders and
scorpions, and the state of preservation of the oldest known fossil
spider from the coal in Upper Silesia, is worthy of note. This
specimen is remarkably perfect, and is embedded in a white kind of
shale, and the body stands out in relief on the surface, showing the
four pairs of legs, the two palpi, and even the coriaceous integument
of the body (see Guou. Mae. 1865, Vol. IL. p. 468).
I was glad to have an opportunity of examining this rare and
interesting fossil when exhibited by the fortunate possessor, Professor
Romer, at the meeting of the British Association in Birmingham, in
1865. Hitherto I have looked in vain for them in the series; but
some day they will very likely be discovered, for we can hardly
believe that such a number and variety of insects inhabited the land
during the Liassic epoch, were not preyed upon by spiders and other
creatures (Insectivorous mammals ?) associated with them.
P. B. Bropis.
VicaRAGE, RowinetTon, WARWICK,
April 7th, 1866.
DIPLOGRAPSUS TERETIUSCULUS IN THE UPPER LLANDOVERY OF
HAVERFORDWEST.
To the Editor of the GroLocicAL MaGazine.
_ §rr,—A short time ago Mr. Lightbody and I, when on our way
to St. David’s to look at the old rocks there, availed ourselves of the
opportunity of examining the two celebrated fossil localities near
Haverfordwest, Sholes’ Hook, and the Gas-works cutting.
In the latter we met with a fossil very much about the position
which has hitherto been assigned it. The strata at the Gas-works
have generally been regarded as Upper Llandovery; and in them
we found the following fossils,—Mdulites favus, Petraia subduplicata
var. crenulata, very abundant ; Stenopora fibrosa, Tentaculites Anglicus,
Orthis biforatus, O. calligramma, var. Walsalliensis, Strophomena anti-
quata, 8. pecten, S. eapansa, Leptena sericea, and Murchisonva gyrogonia.
This is an association quite common. But along with these occurs
Diplograpsus teretiusculus, a form hitherto unknown higher than the
Upper Llandeilo ; and of which Mr. Salter says, ‘‘is a characteristic
Llandeilo species never falling, as I believe, below or rising above that
formation” (Appendix to Memoirs of Geol. Survey, vol. ili. page 330).
Double graptolites have also been met with in the Lake country,
in the Coniston flags of Broughton Moor strata, which are probably
near the horizon of those of the Haverfordwest Gas-works. I am
not, however, aware that D. teretiusculus has been found here; care-
ful looking may very probably discover it.
Yours truly, Ropert Harkness.
Quzen’s Cottrcs, Corx,
9th May, 1867.
On the Metamorphic Origin of Certain Granites, &c. 287
ON THE METAMORPHIC ORIGIN OF CERTAIN GRANITES, &e.
To the Editor of the GroLocicoaL MAGAZINE.
Dear Srr,—Will you kindly indulge me with space for a few
words in reply to Mr. D. Forbes’ letter in the last number of the
MAGAZINE.
The position which I have all along taken up, and from which I
do not in the smallest degree recede, is, that the field-geologist is
capable of affording valuable assistance towards the elucidation of
metamorphic phenomena. ‘To show this was the main object of my
papers. My arguments were founded upon certain geological evi-
dence which, however objectionable and unsatisfactory to Mr. D.
Forbes, was, nevertheless, not of my own creating, but may be seen by
any one who shall take the trouble to examine in detail the regions
described by me.
With regard to the petrological terms employed, I can only say
that I never made any pretensions to be a reformer of our nomen-
clature, and Mr. D. Forbes’ rather warm invectives might therefore
have been spared. The looseness of our terminology is to be re-
gretted, but I have only used the terms in the sense in which they
have been for many years understood by British geologists.!
I shall have no cause to regret this correspondence however, if he who
knows so much about the subject, and who finds that even Phillips,
Lyell, and Dana are, or ought to be, ready to confess their errors, will
1 Mr. D. Forbes takes me to task about my definition of greywacké as applied in
a general way to the great mass of the Silurian rocks of southern Scotland, and twits
me with the fact that Jameson and Macculloch understood by the term “ greywacké”
a definite rock-species. But however definite an idea might attach to ‘“ greywacké”
some fifty or sixty years ago, that term ceased ere long to have any such precise
meaning, and came to be applied to the whole series of strata in our southern uplands,
formerly known as the ‘“‘‘Transition-rocks.”” ‘There was a barbarous word,’’ says
Mr. Jukes, (Manual p. 481,) ‘‘once in use as a kind of synonym of the term ‘tran.
sition,’ this was ‘grauwacké,’ a word now altogether discarded, even in a lithological
sense. It was one of those words that meant anything or nothing, and served merely
to conceal our ignorance of the true history of the rocks to which it was applied.”
My critic ‘‘ expected to have been referred to works specially devoted to the subject’?
of petrology, but the reader will see that the terms complained of were purposely used
in the vague and general way in which they are commonly understood. 1t was,
therefore, quite unnecessary that I should make allusions to those authors whose names
Mr. D. Forbes su abundantly scatters through the pages of the Magazine. I may
just add, that my excuse for using the word greywacké at all, was the want of some
convenient general term which should not mean more than words like ‘‘Sand-
stone,” ‘“‘shale,” etc. Some such term is necessary. Recurring for a moment to
another of my critic’s complaints, the reader may be amused when he finds Mr. D.
Forbes admitting that, if instead of the word “ certain,” I had used “ possible or even
probable,” he would not have objected to the paragraph where I speak of the meta-
morphism of aqueous strata into crystalline rocks, like granite, diorite, hyperite, etc.
Now I have already quoted (p. 181) the statement of one of our most eminent author-
ities upon this subject, Dr. Sterry Hunt. That gentleman has remarked of certain
crystalline rocks that they ‘‘have by most geologists been regarded as rocks of igneous
origin, whereas they appear to be for the greater part undoubtedly altered sedimentary
layers or masses.” Dr. Sterry Hunt, it must be supposed, is well acquainted with all
that has been done in this department of science, and since he thinks the use of the
word “undoubtedly” quite justifiable, I cannot see why the word ‘certain’’ should
require to be so loudly protested against.
288 Obituary.
no longer retain locked up in his own mind such an invaluable store of
knowledge, but will forthwith hasten to render it available for the
edification of the geological world.
Iam, dear Sir, faithfully yours,
JAS. GEIKIE.
Kitmarnocx, 13th May, 1867.
MISCHiOiAN hOUS.
On THE “ Occruston ” of Hyprogen sy Merrorte Iron.
Ar a meeting of the Royal Society, held on Thursday, May
16th, Thomas Graham, Hsq., F.R.S., F.G.S., read a paper, the subject
of which was suggested by a previous one communicated to the
Society in June last. The author has now examined the “natural
gases” of meteoric iron. The Lenarto iron, when distilled in vacuo
(by means of Sprengel’s Mercurial Exhauster), gave 2°8 times its
volume of gas—85 per cent. of which was pure hydrogen. It is
evident that the iron must have “occluded” its hydrogen from a
similar atmosphere to that proved by Messrs. Huggins and Miller
to surround many of the fixed stars, of which Alpha Lyre is the
type. The discovery is a remarkable confirmation of the results of
Spectrum analysis.—W.C.R.
@Oi3 LEO) A ee WZ.
Dr. JAmrs Buack.—We regret to have observed the notice of the
. decease of Dr. James Black, an old geologist, at Hdinburgh, on April
30th last. at the advanced age of 79. He formerly resided at
Bolton-le-Moors and Manchester, where he was widely known
and generally esteemed. He was a graduate of the University of
Glasgow, and Fellow of the College of Physicians of London, and
actively engaged in scientific pursuits, in addition to his profession,
but chiefly devoted himself to Geology and Antiquities. He joined
the British Association for the Advancement of Science at its com-
mencement in 1831, and had the honour of being elected a Fellow
of the Geological Society of London in 1838, and that of France in
1848. When residing in Manchester he belonged to its Geological
Society, and took an active part in its proceedings, both as member
and office bearer, and also to the Philosophical Society of that city.
He contributed numerous papers to each, those to the latter being
chiefly archeological, and among those to the former may be men-
tioned—“ On the Object and Uses of Geological Research,” in 1841 ;
“ View of the Geology of the Isle of Arran,” 1846; ‘ Helectic View
of Coal Formations,” 1847; “Submerged Forests of Great Britain,”
1843 ; “On the Diluvium of Bolton,” 1845 ; “On the Elevation and
Depression of the Crust of the Harth,” 1851. He was an assiduous
collector of rock and fossil specimens from South Lancashire, and
presented a large number to public museums, besides keeping up a
considerable private collection.—J.W.B.
1 On the absorption and dialytic separation of gases by colloid septa.
Geol. Mag. 1867. Voll. Pl. 3a
———————
Mig)
ee
G. R. De Wilde, fecit. ailes & Co., Imp.
To illustrate papers by the Rev. T. G. Bonney, & Mr. Tuomas Bett.
Figs. 1 & 2, Glacial action near Llandudno.
Figs. 3-5, New Trilobites, from North Wales.
a =
THE
GEOLOGICAL MAGAZINE.
No. XXXVII—JULY, 1867
Ome EGE AL, “Alin EC eS.
ne
T.—On Traces or GuacrtaL AcTION NEAR LLANDUDNo.
By the Rev. T. G. Bonney, M.A., F.G.S.
(PLATE XILI., Figs. 1 & 2.)
NYONE accustomed to the peculiar outlines which ancient ice-
“k. action has produced in the Alps, cannot fail to be struck, at the
first glance, by the contours of the upper parts of the Great Ormeshead
and of the Carboniferous Limestone range which extends from near
the village of Rhos to the Little Ormeshead; and a more minute
examination only strengthens the conviction that, while the leading
outlines of the hills are due somewhat to upheaval, but mainly to
denudation—probably marine, the surface of the higher ground has
in many cases been affected by ice.
The following notes were made during a brief visit to Llandudno
in the month of April last. They refer chiefly to (a) the Great
Ormeshead, (b) the Little Ormeshead, (c) the Coast section between
the former and Conway. The bad weather and the shortness of my
stay have made them less complete than I could have wished, but
still they may be of use in calling attention to a neighbourhood at
once so accessible and so interesting.
(a) The upper part of the Great Ormeshead is an undulating
plateau of Carboniferous Limestone, in places almost bare of vege-
tation. Immediately on gaining this by the path which slopes up
the steep south-western face of the hill, from above the ruins of
Gogarth Abbey, one is struck with the general resemblance of the
surface to that of some of the higher limestone districts in the Alps;
for example, that between the Schwarenbach Inn and the Gemmi Pass.
Large blocks of limestone are scattered about, especially in the
neighbourhood of the north-western angle of the plateau. One re-
markably fine mass (Plate XII., Fig. 2) is about 5ft. Tin. in height
and 7ft. 2in. by 7ft. in breadth and thickness. It is very flat on the
under side, and rests upon three or four projections of the rock below.
Several of these blocks differ slightly in lithological character from
the rock on which they lie; for they consist of a very hard kind of
limestone, which, when broken by the hammer, does not exhibit the
usual sharp and somewhat conchoidal fracture common in the Car-
VOL, IV.—NO, XXXVII. 19
290 Bonney— Glacial Action near Llandudno.
boniferous limestones, but crumbles away more like indurated clay.
It can be found in situ on a very slight eminence in the neighbour-
hood. I could not discover any distinct trace of moraines; which,
indeed, could hardly be expected, owing to the absence of peaks.
Probably in the glacial epoch the Great Ormeshead was a low island
with its undulating icy cap (of no great thickness) broken here and
there by a scarcely projecting ridge of rock.
The precipitous sides of the Great Ormeshead appear to me to
bear distinct traces of the action of the sea in the form of steep lines
of cliff with hollows and furrows at intervals. Its eastern face con-
sists of two well-marked cliffs, separated by a sloping talus thinly
covered by a reddish marly clay containing many angular fragments
of limestone. The base of the lower cliff is washed by the sea ; and
it is instructive to compare the wave marks on it with those exposed.
some 200 feet or more above in the face of the upper cliff. Shells of
Patella vulgata and Littorina littorea are not rare in the clay of the
talus by the footpath near Pen-trwyn.
On the §.E. of the Great Ormeshead is a lower eminence called
Pen-y-Dinas (on which are the remains of a British fort), separated
from the main mass by a hollow, which opens out on the one side
towards the town of Llandudno, on the south, and on the other to the
sea, on the east. A deposit of reddish marly clay, with angular
fragments of limestone, covers the lower parts of this, and is of con-
siderable thickness in the neighbourhood of the sea. In the upper
part of the hollow, near Gwydfyd Farm, is a bed or pocket of light-
buff sandy marl, mixed with fragments of chert, which has been
described by Mr. Maw in an interesting paper in this Magazine
(Vol. IT. p. 200).
This is covered by the clay, which is here from two to three feet
thick, and contains shells in considerable numbers. In a few minutes
I collected many specimens of Patella vulgaia, Littorina litiorea,
Mytilus edulis, with an ostrea (both valves), and three separate
valves of Tapes (pullastra?). This clay, both here and elsewhere,
appears to have been deposited after the ground had pretty nearly
assumed its present configuration, and to have not undergone much
denudation during the process of upheaval.
Again, on the 8.W. side of the Great Ormeshead, just beyond the
house at present belonging to the Dean of Christchurch, we find,
below the fine line of limestone precipices, a steep talus, the lower
part of which has been destroyed by the sea, and a cliff of soil and
clay thus formed. In the upper part of this cliff, beds of marine
shells occur with partings of dark brown soil ; as, however, I con-
sider these to be kitchen-middens, I pass them by on the present
occasion. Below these we have the following section: (1) reddish
clay, with many angular fragments of limestone and rolled trap-
pebbles—about 2ft.; (2) reddish sand, yellower in upper part, with-
out pebbles—about 3ft.; (8) talus of fallen sand and clay—about
4ft.; (4) the pebbly shore. As the cliff is followed to the N.W., (1)
is seen to thicken out rapidly and form a cliff some fifteen or twenty
feet high, in which are many large angular limestone boulders.
Bonney— Glacial Action near Llandudno. 291
(6) The undulating outlines of the chain of the Little Ormeshead
are also strongly suggestive of glacial action, and upon that hill are
two shallow but well-marked valleys, whose contours can, I think,
be due to no other cause. One of these is on its western face, and is
clearly seen from the neighbourhood of Llandudno (Plate XII. Fig.1).
It is enclosed by two low ridges; one of these falls rapidly down to
the conspicuous gap which isolates the Little Ormeshead from the
rest of the range; the other, descending seawards, ultimately forms a
broken face of rock. The peculiar curves of these ridges and of
their inner slopes, with the form of the bed of the valley, which in
the upper part is scarcely masked by a thin turf, can only be ex-
plained by the action of a glacier. Nor is this all: about the lower
third of the hill is covered by drift, the rock disappearing under a
sloping bed of it, which sweeps gently down towards the west. The
sea has eaten away a large portion of the northern side of this, and
formed cliffs which, in places, cannot be less than 50 feet high. If
we proceed along the shore to the place where this drift rests upon
the limestone, we find that the latter forms a steep cliff or rapid
broken descent, which still preserves the rounded contour indicative
of ice-action. In the upper part of the clay cliff, a bed of large
angular boulders, all apparently of limestone, is now exposed a few
feet below the surface of the ground. This thins out on each side,
and appears to be thickest in the part nearest to the middle line of
the above-named valley. It was quite impossible to reach this bed,
but its greatest thickness cannot be less than seven feet, and it bears a
very close resemblance to a moraine. The clay below also. contains
many chert fragments, and boulders most of which are limestone,
the rest trap and various metamorphic rocks from the district west
of the Conway. One good sized trap boulder was resting in the clay,
a dozen feet or so above the shore, almost in contact with the lime-
stone rock. ‘The land slips have made it difficult to examine the
lower part of this cliff, but a little further on to the west a good section
is exposed, which exhibits below the surface soil: (1) red clay, with
but few pebbles or boulders; (2) a rather darker clay, containing
large limestone boulders, but slightly water-worn, and many pebbles
and boulders of limestone, trap, and metamorphic rocks ; (3) a bluer
clay, containing many small pebbles of slaty rocks. In many places
the lime in (2) has cemented it into a hard conglomerate. Measure-
ments were impossible owing to the steepness and wetness of the
cliff. I did not find shells in any of these clays.’ Again, on the
southern face of the Little Ormeshead, a valley may be seen, which
descends towards the marshy valley leading to Colwyn Bay, with
contours, if possible, more suggestive of glacier action, and ap-
parently with a similar clay in its lower part. A valley of the same
kind may also be observed in the north-western part of the range,
from the road between Rhos and Llandudno; and the new road from
1 It may be worth mentioning that the great curving joints which seam the northern
cliffs of the Little Ormeshead and contribute largely to their graceful outlines, present
remarkably fine instances of slickensides. They can be examined from the shore when
the tide is out.
292 Bonney—Glacial Action near Llandudno.
the former place to Castell Diganwy Hotel cuts, on the northern
slope of the Diganwy hill, through a regular ‘ subalpine’ drift.
(c) We come lastly to the shore section in Conway Bay. Going
from Llandudno, we pass a line of dunes of blown sand, and meet
with the clay at Tremlyd Point. This is the extremity of a deposit
which forms a slightly rising tract on the north-western face of the
Diganwy hills, and appears to be connected with that described
above, and to have once overspread the whole, or the greater part of,
the level Morfa Rhianedd. Here it forms cliffs about 30 feet in
greatest height, and extends along the shore for a distance of about
370 yards. It is capped by a sandy soil from 6 inches to 4 feet in
thickness, which was deposited, after the clay had been reduced by
denudation to its present form—a bank with gentle slopes north and
south. On each of these we find (1) a red marly clay, with but few
pebbles, which rises to the surface and disappears towards the middle
part of the cliff. The upper part of this, immediately under the surface
soil, is of a yellowish tinge, but the state of the cliffs prevented me
from ascertaining whether this change in colour indicated a distinct
deposit or not. Under this is (2) a bluish-brown clay, containing
many boulders of trap and metamorphic rocks from the neighbour-
hood of Penmaenmawr; perhaps 25 feet in greatest thickness.
Many of these blocks contain 20 or 80 cubic feet, or even more; and
scratches, apparently the result of ice-action, may be observed on some.
They are scattered over the shore for a considerable distance seawards.
Below this is (8) a bed of tenacious dark blue clay, full of small
pebbles of a dark slaty rock; it only rises one or two feet above the
shore, but it may be traced for some distance below high water mark.
On the south slope the red clay in like manner replaces (2) and then
disappears under the sand; in which, on both sides of the clay, are.
seams of Mytilus edulis, beds of which occur at intervals along the
coast-section ; but, as these deposits are obviously of an age different
from that of the Glacial drifts, I abstain from entering into particulars
concerning them. A furlong or so beyond, the clay (1) rises from the
shore, and here also is capped by sand, containing beds of Mytilus edulis
and other shells ; and we again find it, after another interval of sand-
cliff, near the Castell Diganwy Hotel. I did not find shells in any
of these deposits. They seemed to have a general correspondence
with those bearing the same numbers in the Little Ormeshead
Section.
To conclude. It would appear, from the above remarks that, after
the limestone hills of the district had acquired their leading forms
by upheaval and marine denudation, the whole district was de-
pressed. ‘The summits of the low rocky islets thus formed. became
capped with ice-fields, which, in places, descended in glaciers into
the sea. At times, very probably, they were united to the mainland
by pack or coast ice. The section on the Conway shore seems to
favour the idea that, at this period, there were oscillations of level,
during which the two lower beds were subjected to slight, denuda-
tion. After the deposition of the uppermost bed of clay there must
have been considerable denudation, either from the action of the re-
Damon—Shells from Pompeii. 293
treating sea or of currents in shallow water. To this must have
succeeded a period of depression, during which the mussel beds were
formed, and then the whole was gradually upheaved above the sea,
probably—at any rate in the case of the Great Ormeshead—not
quite uniformly.
II.—Norzs on a Cottection or Recent SHELLS DISCOVERED AMONG
THE Ruins oF PoMPEII, AND PRESERVED IN THE Musro Borpon-
1co AT NaPLEs.
By Rosert Damon, F.G.S.
MONG the many singular discoveries made in the ruins of
Pompeii, and deposited in that most interesting of Museums,
the Museo Borbonico, in the city of Naples, are a variety of shells,
principally species now found in the Mediterranean Sea, and so far of
interest as an illustration of the persistency of certain known species
within the historic period, no difference whatever being observable
between the disinterred and living specimens. On aclose examination
I observed, besides those from the neighbouring seas, species from
distant countries, for example:—Conus textilis, Triton femorale,
Meleagrina margaritifera (Pearl Oyster), species only found in the
Indian and Hastern seas. I think, therefore, that this may be re-
garded as part of a Natural History collection. Assuming the truth
of this conjecture, its antiquity is without a precedent. Did the original
proprietor form one of a Natural History Society of Pompeii, of
which the distinguished Naturalist Pliny, who perished at Pompeii,
was amember? Jt would also be curious, in these days of research
for priority of names, to know how they were described. Such a dis-
covery might disturb existing nomenclature, and increase the per-
plexity already felt in naming collections. But laying aside fanciful
conjectures, the collection is further instructive from the condition
and perfect preservation in which the specimens are found, after an
interment of nearly 1,800 years. Besides the collection in the Museo
Borbonico, there is still standing in a villa at Pompei, a fountain
decorated with shells of the Mediterranean, one species of which, viz.
Murex Brandaris, retains its colour and general freshness and is not to
be distinguished from living examples; while the same species, from
the Italian Tertiaries, are colourless and in that friable condition
characteristic of shells even of the most recent geological period, point-
ing. like other discoveries, to the great antiquity of the most modern
Tertiary deposits as compared with the era of the human race.
The following is a list of the species which I was able to identify
in the Museo Borbonico :—
Triton nodiferum, Lam. Pectunculus siculus, Reeve P. glycimeris
» corrugatum, Lam, var Lam,
» jemorale, Lin. sp. cf violascens, Lam.
Murex Brandaris, Lin. Meleagrina margaritifera, Lin.
» trunculus, Lin. Tapes pullastra, Forbes & Hanley.
Dolium oleare, Lin, Lutraria elliptica, Lam.
Cyprea pantherina, Solan. Cardium echinatum, Lam.
» lurida, Lin. * rusticum, Lin,
Turbo rugosus, Lin. Helix pomatia and other Helices of the
Conus textilis, Lin. district.
Pecten Jacobeus, Lin, Weymouth, April, 1867.
294 Belt—New Trilobites from North Wales.
JJI.—On some new Trinopites rrom THE Urrrer Camprian Rocks
oF NortH WALES.
By Tuomas Butt, F.G.S.
(PLATE XII., Figs. 3-5.)
N the autumn of 1864, Mr. Ezekiel Williamson discovered frag-
ments of trilobites in some slaty beds belonging to the ‘‘ Lower
Lingula Flags ” of the Geological Survey, on the right bank of the
river Mawddach, a little above its junction with the Eden, and four
and a half miles directly north from Dolgelly. Portions of an Olenus
and of an Agnostus were found, but in too fragmentary a condition
to be determined. Last summer Mr. J. Chamberlain Barlow, of
Birmingham, found the same fossils in great abundance and good pre-
servation on both sides of the Mawddach, opposite to Dolmelynllyn.
During the present year I have, from these beds, added another
species of Agnostus to the scanty fauna; and, after considerable
trouble, in consequence of the rocks being greatly faulted, have
been able to determine the true position of this new fossiliferous
zone.
The fossils that have been found are Olenus gibbosus, Wahl., now
for the first time recorded as British; Agnostus nodosus, sp. nov.,
and a strongly marked variety of Agnostus pisiformis, Lin. The
beds containing these fossils lie about midway between the “ Mene-
vian group” of Mr. Salter, which forms the base of the Upper
Cambrian formation, and a thick series of blue slaty beds cha-
racterized by a great abundance of Olenus cataractes, Sal., and
Agnostus pisiformis, Lin., and separated from each, above and below,
by yellow and yellowish grey flaky and flagey beds that have
received from Mr. Salter the local name of “‘ Cwmhesian flags.”
The following diagram will exhibit more clearly the position of
these beds. The whole of the strata there shown form less than one-
third of the great mass of rocks that have been called “Lingula
Flags” by the Geological Survey, and the topmost of them lies
several hundred feet below the beds containing the well-known
Tingula Davisii. MCoy.
Dark blue and blue grey slaty jointed beds about 1200 feet
thick.
Olenus cataractes, Salter, common. Agnostus pisiformis, Lin.,
common. Lingula sp., rare.
Grey and yellow grey flaky and flaggy beds—about 600 feet.
Agnostus pisiformis, Lin., in upper beds.
Blue and blue grey jointed beds, about 300 feet.
O. gibbosus, Wahl. A. nodosus, sp. nov. -A. pisiformis, var.
obesus.
Yellow grey flaky and flaggy beds, with bands of hard grey
grit—about 400 feet.
Dark blue beds—about 500 feet.
Puradoxides, Conocoryphe, Agnostus, Microdiscus, etc., etc.
Menevian group, Salter.
Lower Lingula Flags of Geological Survey.
bas
PS
fe
“Ss
ae
URGE Us Op
7
O
I
7°
col. Mag. 186
G.
‘\)
\t
‘Tmp-
Iiailes & Co..
oo
De Wilde. fecit.,
Rk,
1.
CG
PHOLAS-BORINGS,
NEAR Torquay, DEVONSHIRE,
Belt— New Trilobites from North Wales. 295
Description or THE Fossitis.—I. Agnostus nodosus, sp. nov. (Plate
XII., Fig. 3, a long form, 6 broad ditto, natural size.)
Head, rounded in front, straight at sides, sharply rounded at posterior angles.
Glabella oblong, obtuse, slightly constricted in the middle, entire, supported by a
small angular lobe on each side at base; cheeks, covered with deep reticulating
furrows, radiate next the outer edge; margin narrow.
Thorax consisting of two nodose joints. Axis strongly trilobate; central lobe of
anterior joint with a strong obtuse tubercle. :
Tail shaped like head; axis trilobate, nodose; central lobe two-thirds the length of
tail, narrow in front, widening in the middle, then constricted strongly, and widen-
ing again towards the end; furnished with an oblong blunt tubercle one-third its
length of its base. Lateral lobes each composed of two rounded triangular joints ;
limb covered with reticulating radiations, divided by a groove reaching from end
_ of axis to margin. Margin narrow, probably furnished with short spines, but not
sufficiently preserved to show them excepting obscurely in one specimen. :
Locality: River Mawddach, above junction with Eden and opposite Dolmelynllyn, in
“ Lower Lingula Flags.”
Il. Agnostus pisiformis, Lin., var. obesus. (Plate XII., Fig. 4,
¢ broad form, d long ditto, a b nat. size, c d magd. two diam.)
The typical form of this species is so well known, that I only append the characters
in which the variety differs. In A. pisiformis, the axis of the tail is separated at its
posterior end by one-fourth its length from the margin. In the variety, the axis
reaches nearly to the margin, and in most of the specimens seems to touch it. In
the typical form it is only a little more than one-third the width of the tail, includin
the margin; in the variety it is more than one-half the width, and is turgid an
prominent. Lastly, the grooves in the middle of the axis are but faintly impressed
in the typical form ; in the variety they are deeply marked. The margin of the tail
is badly preserved, but was probably furnished with short spines.
Locality with the above, in ‘‘ Lower Lingula Flags.”’
TI, Olenus gibbosus, Walh. (Plate XII., Fig. 5, a broad form,
b long ditto.)
I have obtained very fine specimens of this well-known Scandinavian species from
the Dolgelly district, and I give figures of the two forms, as Angelin,! Barrande,? and
Salter? have all figured the species with the ocular ridge commencing from between the
two glabella furrows instead of above them, and none of them have shown the strongly
marked articular spaces between the joints of the axis, although Swedish specimens
in the Museum of the Geological Society show both these points clearly. Burmeister
has figured the ocular ridges correctly, but shows the thorax with fourteen joints in-
stead of fifteen, and the tail with six joints instead of five.
It occurs in older rocks than any other of the English species of Olenus, and, taking
the body and tail together, has a greater number of axial rings. It shows some
resemblance to Conocoryphe in its strongly marked ocular ridges and articular spaces,
as well as in its large pygidium and in the facial sutures turning slightly outwards
above the eye; but its true affinities, as shewn by the pointed, unfacetted pleura, are
decidedly with Olenus.
The occurrence of this species in England will most likely be of great assistance in
correlating our rocks with those of Sweden. :
Locality with the above, in “‘ Lower Lingula Flags.”
IV.—PuHotas-Borines, DENUDATION, AND Deposition In 8... Devon.
By D. Macxintosu, F.G.S.
(PLATE XIII.)
HE structure and marine denudation of the district between
Torbay and Babbicombe Bay has been so ably unravelled by
1 Angelin, Pal. Suec. 2 Barrande, Systeme Silurian, Vol I., Pl. 3, Fig. 7.
3 Salter and Woodward’s Chart of Fossil Crustacea, Trilobita, Fig. 13.
* Burmeister, Organization of Trilobites, Tab. 3, Fig. 9.
296 Mackintosh—Geological Notes on Devon.
Mr. Pengelly, as to leave any other observer comparatively little to
say. Among his most important discoveries must be ranked that of
lithodomous perforations in limestone rocks at considerable altitudes
above the sea.
Pholas-borings.—I have lately been hunting for these perforations,
which competent authorities regard as Pholas-borings, and have seen
them in various positions and at different levels, but principally on the
summits and sides of Kent’s Hill and Asheldon (see Plate XIII). The
extremely fresh appearance of the borings where they are only very
slightly protected by vegetation, and even where they are exposed
to the atmosphere, would seem, at first sight, to forbid our assign-
ing to them any great antiquity. But if we are to refer them to the
great glacial submergence, or (according to most geologists) a pre-
glacial submergence, then the preservation of these borings clearly
shows that the prevailing theory of the superficial (not internal)
dissolution of limestone hills by subaérial action is a mere assump-
tion. It may be asserted that the perforations have been preserved
only in the hard parts of rocks, the softer parts of which have dis-
appeared ; but the following facts render it certain that little or no
dissolution of the limestone has occurred since the perforations were
made, or since this locality was last under the sea. On the summits
and sides of the hills, and in the valleys, wherever natural or arti-
ficial exposures of rock occur, they exhibit undoubted wave-marks,
consisting of smoothed and rounded surfaces, grooves, cells, pot-
shaped cavities, etc., on which the Molluscan-borings have been im-
pressed, or by which previous borings have been modified, or par-
ttally effaced. ‘The most decided Pholas-borings do not, so far as
‘ | have observed, occur principally in cliffs, but on the sloping sides
or summits of hills. The highest I have yet seen occur near the
summit of Kent’s Hill, at an altitude of at least 240 feet above the
sea. Many apparent Pholas-borings, especially those which occur on
the edges of limestone strata, or which are associated with a honey-
combed rock-surface, cannot be relied on. When on the face of a
solid mass, they may be more satisfactory ; but the sea is capable
(as may be seen on the rocky beach under the public baths at
Torquay) of forming holes of so many forms and sizes, by the un-
equal disintegration of the rock, as well as by the gyratory move-
ment of silt and stones, that it is scarcely safe to assume that any
holes have been bored by organic agency unless they appear very
cleanly cut, and of a uniform specific shape. The most decided
Pholas-borings I have seen, occur in colonies, and vary in the widest
part from half-an-inch to an inch and a quarter in diameter.
There is a truly wonderful natural arch! at Upton, near Torquay,
the general form of which impressively points to the former action
of the sea. There are numerous holes on the sides as well as on
the roof of this arch. Many of the smaller holes are not unlike
slightly weathered -Pholas-borings, especially those which occur
1 Mr. Pengelly has more than once referred to this arch as a monument of sea-
action, and I noticed it in the Grou. Maa., No. 2, Vol. III. Feb. 1866, p. 68.
Mackintosh— Geological Notes on Devon. 297
within the large pot-shaped cavities. Here, as elsewhere, some of
the holes have been usurped by land-shells.'
- The testimony of the above Pholas-bored, grooved, pitted, and
honey-combed rock-surfaces to marine denudation amounts to this:
they show that the sea has not only stood at various levels up to a
height of at least 240 feet above existing mean water-mark, but that
many of the larger features of land surface with which they are asso-
ciated have been formed by the sea. The forms of the cliffs are
evidently a part of the same class of effects, and are, therefore,
likewise of marine origin, while the preservation? of wave-marks
and Pholas-borings proves the extreme slowness of atmospheric action,
and thus furnish a negative presumption in favour of the sea, and
not the atmosphere, having been the primary or great denuding
agent. Not only are the phenomena of denudation in this district
clearly marine, but those of deposition or accumulation point in the
same direction.
Valley of Kent's Cavern—The main valley, on the west side of
which this celebrated cavern is situated, runs 8. and N. from sea to
sea, or from Torbay to Ansty’s Cove. It is a pass open at both
ends, with too little inclination to give to any supposed former
stream a denuding power. The principal tributary valley has a
greater slope, but it merges into the valley which leads to Torquay.
No watershed sufficient to supply this valley with a brook possessed
of excavating power, could have existed in this district in post-
glacial times, or since the ground acquired its present general con-
tour. The first denudation of these and other valleys, is explicable
by branching currents having a clear thoroughfare, supplemented by
sea-coast action, producing cliffs. After their excavation, the valleys
must have been filled at least to a certain height (Mr. Pengelly
believes they were entirely filled up) with stony loam, which
was afterwards removed, with the exception of the remnants now
lining their sides, or covering their bottoms. The loam in Kent’s
Cavern is similar to that covering the neighbouring ground. In
many parts it is full of stones, and very unlike a loess or re-
deposition by freshwater floods, while the idea that the sea left the
valley filled with loam up to the level of the cave, so as to furnish
the brook with a bed to enable it to carry the loam and stones into
the cave appears, to say the least of it, a forced explanation. There
1 The late M. N. R. Bouchard, of Boulogne-sur-mer, wrote’ a paper entitled
“ Observations sur les Hélices Saxicaves du Boulonnais,” printed in Vol. xvi. of the
“Annales de Sciences Naturelles,” in which he expresses his belief that these lime-
stone perforations are the work of land-snails. M. Bouchard’s observations were
repeated and confirmed by Miss E. Hodgson, of Ulverstone (see Geologist, Vol. vit.,
Feb., 1864, p. 42). The late Dr. S. P. Woodward—than whom no higher authority
upon Mollusca can be quoted—decided against the snail-theory, and referred the
Ulverstone examples (presented by Miss, Hodgson, and preserved in the British
Museum) to the decomposition of the rock by carbonic acid dissolved in rain-water—
the form of the cavities often resulting from the former presence of fossils. The
writer has seen numerous similar examples of weathered and perforated limestone
rocks at Gibraltar and elsewhere.—H.W.
2 The best preserved borings have retained the appearance of irregularly spiral
ridges and furrows.
298 Mackiniosh— Geological Notes on Devon.
are difficulties connected with the marine theory of accumulation,
but if we suppose the action of waves, currents, and storms at
different tidal levels, and during possible variations of level, arising
from oscillations of the land, many of the phenomena can perhaps be
explained. Mr. Tylor (Quart. Journ. Geol. Soc. Nov. 1866) seems to be
of opinion that the valley was filled with loam up to the level of the
cliff above the cavern, to enable the Mollusks to pursue their boring
operations, but this cliff is so small that a very slight accumulation
of loam beneath it would give a nearly continuous contour to the
side of the valley (see Fig. 1).
Fie. 1.—Diagram of the north entrance to Kent’s Cavern.
(dou.
Ye
L. Loam. xx. Pholas-borings. The dotted line represents Asheldon Hill.
That the cavern was originally excavated or enlarged by the sea
is evident from the arched form of the south entrance, and the
rounded shape of the recesses and parts of the roof. There are
holes (referred to by Mr. Pengelly) on the projecting part of the cliff
above the north entrance, and on the roof of the entrance; and
within the arch of the south entrance (Fig. 2) there are somewhat
similarly shaped holes, all of which may be slightly weathered
Pholas-borings, though very far from decided specimens.
Fie. 2.—Diagram of the south entrance to Kent’s Cavern.
L. Loam, xx. Pholas-borings. Above the loam there is a deposit of Stalagmite covered by a
layer of dark-coloured earth.
On the slope beneath the cavern, if there are not decided Pholas-
borings, there are convincing wave-marks on the projecting rocks.
On Asheldon (the hill nearly opposite Kent’s Hill), I have seen
fresh-looking Pholas-borings at a lower level than the cavern. These
facts furnish a strong presumption, in the absence of evidence to the
contrary, that no flow of water capable of abrading rocks, has been
in the valley of Kent’s Cavern since it was last under the dominion
of the sea.
Mackintosh— Geological Notes on Devon. 299
Nors.—Since the above was written I have found polished circular
perforations, of the size of Pholas-borings, in Stoney Combe, imme-
diately to the south of the railway between Newton and Totnes.
They generally slant upwards on the protected or over-hanging sides
of rocky projections. They are distinct from the vast majority of
small deep holes in limestone rocks, which here, as elsewhere, are
structural cavities, enlarged, but never rendered perfectly smooth and
circular, by atmospheric action.—D.M.
EXPLANATION OF PLATE XIII.
Fig. 1. Specimen of perforated limestone from Asheldon, near Torquay (natural size).
Fig. 2. Borings from the summit of Kent's Cavern Hill, nearly 250 feet above the
present sea-level (natural size).
Fig. 3. Group of Pholas-borings on part of a block of limestone on the side of
Asheldon Hill, north of Kent’s Cavern, about 190 feet abeve the sea (about
one-third the natural size).
V.—On tHe DistrRisurion BEYOND THE TeERTIARY: DISTRICTS OF
Waitt Cnays AND SANDS SUBJACENT TO THE BOULDER-CLAY
Drirts.
By Grorcse Maw, F.G.S., erc.
(Part II.)
HE Pipe-clay beds of Tipperary appear so closely to resemble in
character and position the deposits of the Mountain Limestone
district of North Wales and North Staffordshire, that it may not be out
of place to record some observations made by Mr. C. D. Blake,
of Newton Abbot, in 1862, and kindly communicated to me.
There are also one or two previously published notices of these
deposits, to which reference must be made.
The first record appears to have been made by Mr. (now Sir
Richard) Griffith, in the form of a report in the minutes of the
Royal Dublin Society, on the probabilities of finding coal in Tip-
perary, a copy of which has been obligingly communicated to me
by Dr. Steele ; it is as follows:
Mr. Griffith says, “Expectations of finding coal were also enter-
tained by Lord Waterpark and his tenants on the lands of Scartana,
three miles to the south-west of Cahir. In making a well at this
place a considerable thickness of disintegrated Chert, a white sili-
cious substance, similar in composition to Lydian Stone, was passed
through without meeting with any solid rock ; at the depth of 70 feet
a black, sooty-like substance, arising probably from the decompo-
sition of some vegetable matter, was met with; but as the surrounding
country was wholly composed of Limestone and Lydian Stone with-
out the intervention of any other rock, I have no hesitation in stating
that the black substance found is not connected with, or likely to lead
to the discovery of a bed of coal. So far my examination proved fruit-
less, but in exploring the country to the south-east of Cahir, in search
of some pits, from which I understood white potter’s-clay had previ-
ously been raised, I was enabled to trace an extensive and very valu-
300 Maw—Distribution of White Clays and Sands
able alluvial deposition of that substance, resting on the top of the
Limestone strata. This clay occurs on the lands of Ballymacadam,
Lough Logher, Morristown, ete. ; the principal workings were made
upwards of 25 years since on the lands of Ballymacadam, and Lough
Logher. The first stratum of clay is said to be 30 feet thick ; be-
neath it is a bed of Surturbrand, or Wood Coal, 10 feet thick, exactly
similar to that at Bovey in Devonshire; below which is a second
stratum of clay that has never been sunk through. The old workings,
both at Ballymacadam and Lough Logher, were made close to the
edge of the clay district, where it was not likely to be pure, and no
trials have yet been undertaken in the interior of the valley, where
it is probable a great body will be found.”
A reference to these beds is also made by Mr. A. B. Wynne,
(late of the Irish Geological Survey, and now of the Geological
Survey of India), in the data and descriptions accompanying
quarter-sheet 45 8.E. of the Irish Survey. A fuller account of the
formation is also given by Mr. Wynne in a paper read before the
British Association in Dublin (see abstract, p. 94, of British Asso-
ciation report, 1857), from which I abridge the following. ‘The clay
is found under and about the mine of the old Castle of Ballymac-
adam. The mode of its occurrence is very strange ; for when stand-
ing in the centre of the small hollow which it occupies, at a distance
of about 100 yards on almost every side, the Carboniferous Lime-
stone may be seen to protrude through the ordinary Drift, which is
spread over the surrounding country, and which most probably once
covered this isolated basin of Tertiary Clay, occuping an area of at
most about an acre and a half. One small pit has recently been
opened to a depth of 4 or 5 feet; and in this in sit# was found a
lenticular mass of Lignite. The clay is usually white, more or less
pure, and sometimes of a dun or bluish tinge, smooth to the touch,
and extremely tenacious. The Lignite is brown, and occurs in
different states of decomposition and alteration ; but none of it re-
mains sufficiently perfect to prove what kind of wood it was. Within
the space occupied by the clay occur some of those natural drains so
common to the Mountain Limestone of Ireland, expressively called
by the peasantry Swallow-in-holes, they carry off all the surplus
water accumulated in the pits; one in particular having been used to
drain them wherever they were opened.
“Under about fifteen feet of white clay, containing small frag-
ments of plants, a bed of Lignite is reached, of varying thickness,
from which parts of trees four or five feet in length could be raised
without difficulty ; beneath this occurs the purest and best clay,
which is white (with sometimes a pale shade of blue) and soft, and
has a soapy feel. Lower than this no person has penetrated, as
springs of water bursting up through the clay filled the pits, accom-
panied by so offensive an odour of sulphuretted hydrogen gas as
could scarcely be endured; even now the place is not quite free
from a mitigated form of this unpleasant effluvium, which, as
stated by Dr. Griffith, attends the occurrence of potter’s-clay in
many other places in Ireland, as the south-eastern margin of Lough
Subjacent to the Boulder-clay. 301
Neagh, counties of Tyrone and Antrim; in the parish of Clonoe, in
county Tyrone; and near Lough Ree, in Roscommon. The Lignite
gives forth a heavy and peculiar smell whilst burning, and is
associated with black shales, traces of which were seen near the
mouth of one of the pits; no shells were met with in any part
of the clay.
I am indebted to Mr. Charles D. Blake, of Newton Abbot, for
the following detailed description of the Ballymacadam-clay de-
posits, the result of some borings undertaken so recently as 1 82
with the object of ascertaining the value of the clay for pottery
purposes.
“This deposit, probably the remains of a more extensive one,
of which the chief part may have been removed by flocds, occurs in
depressions, or hollows, in the grey limestone rock, from 100 to 200
feet in diameter, and to a depth of from 40 to 100 feet. Their
form is irregular, and it was not ascertained whether the sides of
the pockets were smooth or rough.
“In the same locality, or near the clay deposits, are numerous
fissures, or ‘swallow-holes,’ in the Limestone rock ; they carry away
the surface water, and are supposed to have outlets near the river Suir,
about two miles below. The level of the river at Cahir is 135 feet
above the sea, and I should think the clay at Ballymacadam lies
from 150 to 200 feet above the river. There is much limestone
drift in the neighbourhood, but generally at a lower level than that
of the clay.
“The stratification of the clay bed is tolerably perfect, and the dip
varies with the angle of the basin; in some cases, as at Bally-
macadam Old Castle, the surface of the ground is depressed con-
formably with the shape of the basin, the beds appearing rather to
line than fill the pockets in which they occur; but in most of the
other cases the surface is smooth and regular, the concavities of the
basin being filled with limestone, gravel, and other drift, apparently
of local origin.
“The different veins or seams of clay under the gravel, forming
the bulk of the contents of the pocket, are numerous but thin; one
or two of the seams are very pure, suitable for white earthenware ;
but they do not occur with any regularity, and therefore could not
be worked with profit. Some of the veins are quite white, while
others are of a brown, bluish, or grey color. Some borings showed
a very thin deposit of nearly black clay, the colour being due to the
presence of Lignite and Pyrites—both much decomposed. No solid
or hard Lignite was met with, though some of the people on the spot
spoke of specimens as large as trees, that had been found where
some small workings had been made at Ballymacadam many years
ago; much of the clay contained free silica in fine particles; the
seams of clay varied considerably in each pocket. Granite, supposed
to be the source of the plastic clay, does not appear to occur
nearer than the county Wexford, at a distance of fifty or sixty
miles.”
Subjoined are the details of a boring at Ballymacadam, also fur-
302 Maw— Distribution of White Clays and Sands
nished me by Mr. Blake, showing the contents of one of the pockets
and representing a section, as follows :—
Ist. Clayey Limestone-drift............ Ws cea Rebudusectiseustes 27 feet.
2nd.” (SO MAS MIbG ic cpcdcigec cms aacssets ae «NR 1 foot.
3rd, Brown, blue, or white clay, interstratified with a
little fine sand and gravel............ceecscsscsesscsees about 31 feet.
4th. Bluish sand, of unknown thickness
59 feet.
Details of Boring.
Limestone-drift, gravel and sand, mixed with yellow clay ......... 27 feet.
Nokb ela nate san:ateee age secesertere tes suemec ee cee amen ecu cele Gaauanes 1 foot.
Tough ‘brown clay, mixed with fime’ gravel 20.02. Jcsssssseccnseneee 9 feet.
Brown clay, striped, withebluve ssc. cegsandcapnesinds cea pones oe'cacttosstececa 2
Brownyelay, with Svavel-ssccconaenscpskscepens saceresoessvsnses -eetenehee Ds
Sandy-grey clay ........0-.ssscsscsecssoecees Beeiioddeciadeciccneenscseatncicacs 1 foot.
Grey clay deribed with blue 1
Sandy-blue clay 1
1
Fine blue clay
Coe ceo roe ee ees Peer esseeoseresossessseseboeese
POP e seer ecee reo se rer cos eeree ress er Dene BOE SO TEST OOD ES eHeneee
COP eee eee ees oes eeened FES COE SOG ls HEOSSOOSE OES ORES HFsonrssorD
Brown clay with fine gravel .......... SRBC ES Sasa candedebacsobaaseHse 2 feet.
Fine blue clay........ “scpobbasoddeada sealeiesisnaneecoeene soem asdccceeu cert 1 foot.
Coarse Drown Clay tie.uh secceateccersekewcreeuesectarmarcoscouncosteah ites 1
Blueyelay/withisantly, Veiistsoc 45. acveuveases ddarecesscceemscommanrees . 10 feet.
59 feet.
At a depth of 59 feet, blue sand, containing water, was reached,
when the boring was discontinued.
The questions bearing on the foregoing facts that invite con-
sideration, relate
1st. To the probable age of these deposits.
2nd. As to whether they are the remnants of a more extensive
formation, that once spread over the whole of the districts in
which they occur, or are mere local deposits produced by
subaérial action, that never much exceeded their present
dimensions.
3rd. Regarding the source of the component materials.
Ath. As to the process of the excavation of the pockets and cavities
in the Mountain Limestone, in which the deposits are almost
invariably preserved.
With reference to age it would be unsafe to assume that these
similar deposits in Tipperary, North Wales, and the Midland Counties
of England, belong exclusively to the same geological period; and the
only fact that can be relied on is their unquestionable infraposition to
Boulder-clay drift, which holds good in all the localities I have.
examined in North Wales and Staffordshire, and seems, also, con-
stant with respect to the occurrence of the deposits of like mineral
character in Ireland : their similar position and physical resemblance
in all the localities is remarkable. Nearly all the examples occur
between the Boulder-clay drift and the Mountain Limestone, and in
nearly every case the same beds of peculiar mineral character are
associated. The soft chert breccias, white clays, dark laminated
clays, white sands, and carbonaceous beds, are recorded from widely
Subjacent to the Boulder-clay. 303
separate districts, and the peculiar dark sooty-like substance is
common to the Welsh, the Irish, and the Staffordshire deposits.
In connection with their infraposition to the Boulder-clay, and,
therefore, the possibility of their Tertiary age, their mineral re-
semblance to some of the Lower Tertiary beds ought not to be lost
sight of, though this fact be insufficient to draw conclusions from
without the evidence of fossils.
The evidence bearing on the question of the original extension of
the beds beyond their present limits, appears somewhat conflicting :
on the one hand, the general limitation to the Mountain Limestone
in far removed localities, and the various levels at which the small
and isolated patches occur, seem to point to a local, and to a certain
extent subaérial agency, the similar mineral character being de-
pendent on an identity of local circumstances and similar sources of
component materials. Qn the other hand, these deposits are not
invariably confined to the Mountain Limestone, and in the case of
the white clays resting on Lower Silurian rocks, west of Conway,
the distance of transport from the nearest Carboniferous Limestone
and Millstone Grit seems scarcely compatible with mere subaérial
agency.
Again, when occurring on the Mountain Limestone, the deposits
invariably occupy deep depressions on its eroded surface, a contour
implying the removal previous to their deposition of the whole of
the Millstone Grit in each individual locality ; but as the sands and
chert-beds of the Millstone Grit appear to have largely entered into
the composition of the deposit, a certain amount of transport
appears indispensable. The Millstone Grit, in many parts of North
Wales, is in a very soft and friable condition; but the local débris,
resulting from its subaérial decay, does not resemble the deposits
under consideration, in which the sorting and separating agency of
water appears manifest in the interstratification of various coloured
sands with laminated-clays and tough pipe-clays in well-defined
beds. This arrangement could not have been produced without the
agency of some body of water, though it is probable that the several
masses of the deposit may have been accumulated within separate
and limited areas.
With reference to the cavities in the Limestone containing the
clay- and sand-beds, and the probable process of their excavation, I
would refer to a suggestion I made in describing the pockets at
Llandudno (GronoercaAL Magazine, May, 1865), that they were
gradually formed by the slow dissolution of the Limestone, and that
this may have taken place subsequently to the deposition of the mass
of the materials occupying them, after the manner of the excavation
of the sand-pipes in the Chalk and Coralline Crag, into which pre-
viously existing superincumbent beds appear to have been gradually
lowered.
The evidence in support of this view is various; the point that
first suggests itself is the difficulty in accounting for the excavation
of a deep cul-de-sac, complete on all sides, by any ordinary process of
either marine or subaérial denudation,—as some force vertically
304 Maw— Distribution of White Clays and Sands
directed seems requisite on any mechanical theory. The effect of
ice, which has been adduced to explain the excavation of rock lake-
basins, complete on all sides, seems scarcely applicable to the
present case, as the walls of the pocket exhibit no evidence of
abrasion or striation, but present a smooth mammillated surface,
such as would be produced by gradual dissolution, and resembling
that of underground cavities in the limestone, which are generally
considered to be due to this process.
Another point to be noticed is, the absence of rocky fragments or
débris, and the striking dissimilarity of the contents of the cavities
to the Glacial beds that overlie them. Had the pockets been
excavated by Glacial abrasion, the entire clearing out of all débris
from the bottom of a deep cul-de-sac would be highly improbable,
and, furthermore, had the pockets been at any time opened and
exposed, the subaérial accumulation of débris from the sides of the
Limestone hills, on which the pockets are frequently placed (as for
example at Nant y Gamer, near Llandudno), would soon have filled
them up. As a rule, however, the pockets are occupied with the
white clays and sands, free from stones and limestone fragments,
and resting on these are the Glacial drifts, entirely dissimilar in
colour and mineral character, and containing both local and foreign
boulders.
A point of analogy with the sand pipes of the Chalk is the tendency
to a vertical disposition, or a conformity to the general shape of the
pockets of the strata occupying them; instead of the beds lying
horizontally or nearly so, as they would have done from direct de-
position in the containing cavities, they are in some cases disposed
vertically or more generally with a steep inclination, dipping towards
the centre; they are also frequently disturbed with singular con-
tortions and full of little faults and slips, which, from the formations
being strictly confined within the limits of the cup-shaped cavities,
appear, at first sight, difficult of explanation ; if, however, the gradual
dissolution of the underlying limestone is taken into consideration, the
singular arrangement of the beds is at once accounted for. The strata,
with a disposition originally more horizontal would, in gradually
sinking, conform themselves to the changing outline of the slowly
deepening cavity. This sinking and dislocation is evident in nearly
the whole of the examples before referred to. Mr. Binney describes
the occurrence of an almost vertical mass of pebbly gravel in the
midst of a mass of pipe-clay occupying a pocket at Caldon Hill
Limestone Quarry; and Mr. Brown, in his paper on the Drifts of the
Weaver Hills (see p. 201), states that the white clay and sand
deposits below Caldon Low, in the same neighbourhood, betrays its
existence by deep sinkings in the surface of the ground. The Welsh
deposits, near Llandudno and on Holywell Mountain, appear also to
have sunk down since their original deposition, rendered evident by
their tendency to a vertical or steeply concave arrangement, and
accompanied by the dislocations before referred to. The Irish beds
exhibit similar evidences of altered arrangement. Mr. Blake ob-
serves that the dip of the stratified clay varies with the angle of the
Subjacent to the Boulder-clay. 305
outline of the containing limestone basins, and that the beds seem
rather to line than fill the pockets. Also that the surface of the
ground is sometimes depressed conformably with the shape of the
basin. Mr. Wynne, in the descriptive letter-press accompanying
quarter sheet, No. 45, S.E. of the Irish Survey, observes, with
reference to these beds, that “ where the lignite appears at the sur-
face, it seems to have a dip at a high angle southwards.” This, I
apprehend, must be an inclination from the circumference of one of
the pockets. One of the conditions requisite for the gradual dissolution
of the limestone—the existence of underground outlets for the dis-
charge of the water, removing the lime in solution, is always present.
They are noticed by Mr. Blake and Mr. Wynne, in connection with
the limestone pockets in Tipperary ; and by Mr. Brown, at the seat
of these deposits on the Weaver Hills. In North Wales there is
evidence of the existence of underground outlets in the fact that the
water freely drams away from the pockets or basins, and Swallow-
holes are occasionally visible on parts of the Mountain Limestone
range not obscured by the deposit. In the mining operations of the dis-
trict it is not at all uncommon to break into these cavernous openings
in the Mountain Limestone. At Glan Alyn Mine, near Mold, a large
cavern occurs at a considerable depth, and discharges a portion of the
mine water; and at the Britannia Mine, near Llanarmon, a cave
lined with stalactitic deposits was found at a depth of 25 yards, also
affording a passage for the water.
Perhaps the most striking fact bearing on this point is the oceur-
ence of great masses of redeposited lime, as Tufa (see GroLocioaL
Maeazinz, June, 1866), at the foot of the limestone range in which
the pockets occur. Near Caerwys, in Flintshire, in the valley con-
necting Mold with the Vale of Clwyd, many hundred thousand cubic
yards of 'Tufa have been deposited immediately adjacent to a cavernous
channel in the limestone cliff directed to the neighbourhood of the
pockets.
A deposit of Tufa has also been noticed near Llangollen, and I
am informed by Mr. Beckett, of Wolverhampton, that other masses
also occur, somewhat further removed from the Mountain: Limestone
range: viz., on the eastern side of Wepre Brook, in the parish of
Hawarden, in Flintshire, about half a mile below Euloe Castle, where
it occupies a considerable breadth of steepish bank, and is remarkably
full of calcified ferns and other local plants; Tufa also: occurs on the:
banks of the river Alyn, at Gwersyllt, near Wrexham. It has been.
already noticed that mixed and interstratified with the sand occupy-
ing the cavities, occur beds and patches of a very white and smooth
clay, resembling Kaolin in appearance, the origin of which, from
the mere mechanical degradation of previously existing beds, seems
difficult to account for, as in its purity and whiteness it is unlike
anything that could have been derived from the wearing down of the
Carboniferous beds. The question suggests itself whether it may
not be the insoluble matter contained in the limestone, left behind
after the dissolution of the carbonate of lime and iron. The purest
limestone contains a small quantity of silica and alumina, that
VOL. 1V.—NO, XXXVII. 20
306 Maw—Distribution of White Clays and Sands
could not be removed in watery solution; and if the pockets have
been excavated by the chemical dissolution of the limestone, we
should expect to find its insoluble constituents left behind in the
pockets.
With the object of ascertaining whether the beds of pure white
clay could possibly represent such residue, I procured from Dr.
Voelcker the following analysis of the Carboniferous Limestone,
forming the walls of the pockets, and of the white clay partly
occupying them :
Analysis of Limestone Wall of Pocket, Nant y Gamer, Llandudno.
Moisture and combined water ............ 0:95
Oxiderotglrones ces. ee. fk eeeereceasees 0:88 { Soluble in very dilute
ATM IN aie ieee senebabicabee seijetaee eee 0°15 Hydrochloric Acid.
Carbonate of Lime in a little Magnesia... 95:53
Ors) ii Th es ebsnaccdiisa ag soca sdeooode 0°85 Insoluble in dilute Hy-
JATINEIEO solseo gob ahononanscoundadeg) dageseeedads 0°26 d Ba Tac
Walid aa dle a 0-08 | stochlore Acid,form-
Magnesia and Alkalies (by difference)... 0°28 ae hay ee Cente
Silica jew, a eee gues uel 1252.) cul lie teen AML a
100-00
The carbonate of lime and iron would be the constituents re-
movable in solution by water charged with carbonic acid, and
these we find actually redeposited in the neighbourhood in the shape
of ochreous Tufa. The remainder would consist principally of
silica and alumina, with traces of the other constituents; and with
such insoluble residue the following analysis of the white clay
closely corresponds :
Analysis of the White Clay from Pockets in Mountain Limestone,
Nant y Gamer, Llandudno.
Moisture and Water of combination .............see00:: hae we yaa a 9-96
OXIME LOL TOM eee eh ee ha ashlee Waa ook settee dares sibewesde 1:84
Alumina ........ BM Jeo aise cata srawalslariasielstarsaiiewie pale else oisale elastance aleteettante 26°43
TEM i osee eee ceaattep cn osatene sense cepiceulcsse 5 Saeiceeeiulcoa eae tS UGE nee 1:22
Magnesia ..........cesssocenssnavensccscrsensncnccsceseresecssceercercecenes ise 0:82
Alkalies (by difference) ....s.ccsccocccensscsssconvccnsecssrenscees odo seaddclo 0°55
Saye REL Res mena din MePicweieloauwines eee cnememee iS Seeatepeeuse aca 59°18
100:00
The proportion of silica is somewhat in excess of that contained
by the insoluble residue of the limestone; but as both the clay and
the limestone would vary somewhat in their composition, the corre-
spondence is as close as could be expected from the result of a single
analysis. ,
If we suppose this white-clay residue to be gradually thrown off
from the sides and bottom of the cavities with the dissolution of the
limestone, the sands from the Millstone Grit deposited from above,
and the whole contents gradually lowered as the cavities deepen,
we should expect just such a result as the arrangement observed at
Nant y Gamer, Holywell Mountain, and the Weaver Hills, viz., a
kind of rough stratification broken up, bent and faulted, and here
and there inverted. The mass being gradually added to, both from
Subjacent to the Boulder-clay. 307
below and above, accompanied by a continual sinking, would assume
just that complexity of arrangement the beds display, which, at first
sight, appears quite unintelligible, and which, I believe, no other
explanation will satisfactorily account for. The probable derivation
of these white-clays from the dissolution of the limestone, suggests
the question as to whether the beds of pure white impalpable clays, so
largely composing the Lower Tertiaries, may not have had a similar
origin from the dissolution of the Chalk before being transported and
interstratified with other materials.
VI.—Discovery or a Hy#na-prn, NEAR LAUGHARNE,
CARMARTHENSHIRE.
By Henry Hicks, Esq., M.D.
HE announcement of the discovery of a Hyzna-den, near Laug-
harne, may possibly be of some interest to those of your readers
who may be inclined to visit the bone caverns of South Wales during
the approaching summer. In the autumn of last year J. R. Allen,
Hsq., of Albert Terrace, Regent’s Park, London, was good enough
to send me word that, during a few days’ stay at Laugharne, he had
discovered some fragments of bones in a limestone cavern known as
the “Coygan cave ;” adding, at the same time, that it was not known
in the district that any one had hitherto found bones there, or that
it had ever been explored for that purpose.
Accordingly, we arranged to meet there soon afterwards, and
during our exploration were so fortunate as to obtain numerous
fragments of bones, teeth, jaws, etc., and at the same time we were
able to satisfy ourselves that it had evidently been at one period
a Hyzena-den, until then unexplored. I have since visited the
cavern several times, and exhumed a large number of bones be-
longing to Hyena spelea. Rhinoceros tichorhinus, Elephas primigenius,
Equus, Cervus tarandus, Cervus (small var.). All the bones were
forwarded to W. Boyd Dawkins, Hsq., F.R.S., for examination, and
he has kindly determined the species, and sent me the following list
with some notes on our joint collections :—
Hyena spelea, six jaws with teeth, also separate teeth and bones.
FEhinoceros tichorinus, numerous teeth and bones.
Elephas primigenius, six teeth (or parts of ), portions of tusks and bones.
Cervus tarandus, shed antler-guard, etc.
(small var.), jaw, etc.
Equus, numerous teeth, etc. .
He says, “all these remains were derived from a Hyzena-den, and
were introduced by those animals in every case. The lower jaws
are in every case without angle or coronoid process, and the Rhino-
ceros humeri, tibia, and radii, are gnawed in exactly the same
manner as those from Wookey Hole. The teeth, also, of the Hyzenas
indicate every variety, from the whelp to the adult in the decline of
life. A lower jaw belonging to Mr. Hicks shows remarkably the
results of the diet of the hyenas on their teeth. The first of the
308 Hicks—Discovery of a Hyena-den.
two conical bone-crushers is broken, and the fragments of bone
gliding down upon the unarmed gum have caused inflammation of
the periosteum. One of the hyzna’s last lower molars exhibits the
accessory cusp, which is but seldom developed. The remains of the
Rhinoceros are most abundant.”
The cavern is situated in a Carboniferous limestone hill, called
Coygan, about two miles to the south-west of Laugharne. The
entrance is about 250 feet above sea-level, and easily accessible.
PLAN OF THE CoyGaN CAVE, NEAR LAUGHARNE, CARMARTHENSHIRE.
A. First chamber. 3. Central chamber. c. Westerly compartment. ov. Northerly compart-
ment. e. Theentrance. x x. Indicate the spots where the remains were chiefly discovered.
The orifice is low and narrow, about four feet by three. From it a
low tortuous channel extends inward for about twenty feet; this is
so low in some parts that it becomes difficult to pass in a creeping
position. A moderately lofty chamber is then entered, which again
leads to another and larger chamber—the principal or central
chamber—about twenty feet wide by twelve in height. It then
branches off into two compartments, a northerly, and a westerly
one; the former extends inward for about seventy feet, and the
latter about fifty, when both terminate in rather narrow fissures.
The entrance channel, the two chambers, and the westerly com-
partment, have a very thick flooring of stalagmite, which has
not yet been broken through. The northerly compartment,
therefore, is the only one which has been searched; this was
covered over but thinly and partially, and hence easily worked.
Walker—Coprolite Workings at Upware. 309
After breaking through this thin coating we came to a reddish
earthy soil, with bones imbedded, some of them almost on the sur-
face, others a foot or two deep. It is impossible, as yet, to state
what depth of soil occurs here, though evidently it is somewhat
considerable; fragments of bone occurred rather plentifully through-
out, much more so, however, in some parts than others—heaped
as jt were in favourite haunts. The bones are all in a good
state of preservation, seldom, however, in their natural form, and
almost in every instance giving unmistakable indications of having
been more or less gnawed. ‘There is no evidence whatever to show
that the sea has entered the cavern at any time since it was inhabited
by the hyzenas, nor have we fluviatile deposits present, nor as yet
have we found any traces of its having been a human habitation,
like Kent’s Hole and others. No worked implements, flint or bone,
turned up during our explorations; possibly, however, further dig-
gings near the entrance, or in the chambers, may reveal traces ; but
up to the present time we have discovered nothing of that nature.
St. Davin’s, May, 1867.
VIL.—On some new Coprotite WorkKINGS IN THE FENS.
By J. F. Warxer, B.A., F.G.S., ete.
[Read before the Yorkshire Philosophical Society, May 7th, 1867.]
N the evening before I left Cambridge last term, I was informed
by a man who brings me fossils, that some new coprolite dig-
gings had been opened in the Fens. I was unfortunately unable to
visit the workings then, but since my return to Cambridge, I have
explored them in company with Mr. Moore, of St. Catherine’s College.
The workings are situate about a mile from Upware, which lies
about twelve miles from Cambridge, and seven from Ely.
Upware is known to geologists as the nearest locality of the Coral-
line Oolite to Cambridge. The bed differs from the “Sandy con-
glomerate bed,” in being less ferruginous, and containing more lime,
probably derived from the Coralline Oolite. The nodules are mixed
with pebbles, which are picked out by women and children; about a
third part is waste. Roller washers are used here as at Sandy. The
sections exposed by the workings differ considerably; the best I
have seen was on the occasion of my last visit to the pits.
7. Surface, black peaty soil, often containing bones of red deer, horse, etc. about 1ft, 6in.
6. Layer of light-coloured. @onralilienMesnddtres) Wiles Picci aneM ona, aces CMO
eo Satid, (CHiteU Dy, ule WOLKIMCHNOELL) Wise kos jsccy sa, fess see gn ew bo G
4, Vein of dark-coloured purontes DOG), (doo. Bon, lhaoa! Coes ood anni gaa)! ')
3. Silt osc! eck Listas
2. Vein of ‘dark Coprolites. et)
1. Clay (not pierced) bo) Vege
At another working —
Sand... Traits idea aioe op heeds lieve Ueeeliin-dopitact biases, tise) GLur UID
Coprolitic vein... Gio COW Nocti won usta coc EG wi ang Mabog aad 23) Ab
Conglomerate (hard rock) See siyaet) | caulytansiy Vesw © loser MecUMEN cl ahriteren nceat MO uA:
Light-coloured Sand and Clay ... eee eee
The three layers of nodules Be ecu in the first Hociiod fabs be-
310 Waiker—COoprolite Workings at Upware.
come blended into one, but the top layer differs in the nodules, being
of a much lighter color, and I was informed that they were less
valuable.
The hard rock (conglomerate), consisting of nodules and pebbles,
cemented together chiefly by carbonate of calcium, varies consider-
ably, sometimes being so firm as to be penetrated with difficulty; at
other times the coprolites near the clay are easily worked. The
Kimmeridge Clay is not pierced, as there is no occasion for a well,
the works being near the river. Among the nodules there are found
phosphatic shells, as in the bed near Potton. They consist of frag-
ments of Ammonites, (and some of the nodules are marked by impres-
sions of Ammonites( casts of brachiopoda, conchifera and gasteropoda,
also remains of large Belemnites and Gryphca dilatata, composed of
carbonate of calcium, occur, derived from the Oxford Clay.
I have obtained the remains of most of the fishes and reptiles
found at Sandy.
Spherodus gigas Ag. Hybodus (Spine and Sphenonchus).
Gyrodus Psammodus reticulatus Ag.
A steracanthus ornatissimus Ag. Edaphodon.
Pycnodus gigas?
Of reptiles, the remains of Phosaurus, Ichthyosaurus, Plesiosaurus,
Dakosaurus, and a tooth of the Iguanodon, have been discovered.
The fossils proper to the bed consist of carbonate of calcium, thus
differing from the ferruginous shells of the Sandy conglomerate bed.
Sometimes masses of these shells are found cemented together,
chiefly in the lower part of the deposit. There are found large
sponges, bryozoa, serpule, etc.; the commonest shell is Terebratula
sella, of which numbers can be obtained of the workpeople, but on
examining the heaps it does not appear to be so plentiful. I have
obtained the following species :—
Belemnites, sp. Rh nchonella Gibbsiana, Sby.
Scalaria, sp. ee antidichotoma, Buy.
Cerithium, sp. »» paucicosta 2? (probably new).
Turbo, sp. p depressa.
Nerinea, sp. 09 nuciformis, Sby.
Trochus, sp. Terebrirostra neocomiensis, a’ Orb.
Opis neocomiensis, d’Orb. Terebratella oblonga (small variety).
Cardium, sp, Terebratula sella, Sby.
Cyprina, sp. » prelonga, Sby.
Trigonia spinosa, Park. 55 depressa, Lam.*
Pecten cottaldianus, d’Orb. . hippopus, @ Orb.
» Carteronianus, d’ Orb. T. (Waldhimia) tamarindus, Sby.
Janira neocomiensis, d’Orb. * 39 celtica, Mor.
Pheatula Carteroniana, a’ Orb. 4 moutoniana, d’ Orb.
0 , 8p. D Bryozoa, ete.
Ostrea macroptera, Sby. Serpule.
Ostrea, sp. Spongie.
* The largest specimen of 7. depressa ? I have obtained is 2°8 inches long, 2°5
inches in width, and 1:1 inch in depth.
This bed, and the conglomerate bed near Potton, appear to be of
the same age, and probably, also, the Farringdon beds, viz., Lower
Greensand, containing large numbers of fossils derived from other
formations.
——
Tho Davidson. del &lith..
SYRINGOTHYRIS . Wiauchell
Dawvidson— On Syringothyris. 311
VIJI.—PrrroraTE AND IMPERFORATE BRACHIOPODA.
By Tuomas Davinson, F.R.S., F.G.S., ete.
/ (PLATE XIV.)
answer to the observations made by Professor King in the
June number of your valuable Magazine, I am quite ready
to admit that several very important points in connection with
the shell-structure and interior arrangements of the Spiriferide have
still to be determined, and I am always delighted when some new
light can be thrown upon the subject.
No one has devoted as much time or shown a greater degree of
ability in the careful examination of the shell-structure of the
Brachiopoda than Dr. Carpenter has done; and I have no hesitation
in reiterating that I cannot doubt the trustworthiness and accuracy
of his investigations. Dr. Carpenter has repeatedly shown the abso-
lute necessity of thin sections viewed with adequate microscopic
power; and it, therefore, surprises me, that Professor King should
so often endeavour to throw discredit on that gentleman’s observa-
tions, on the strength of surface-markings observed with a “‘ hand-
magnifier.”
Now, with reference to Spirifera cuspidata, Dr. Carpenter assures us
that, after having carefully examined by the aid of first-rate instru-
ments the well-preserved shells of several specimens, he found in them
a total absence of perforations; but that a deceptive appearance of dots
upon certain portions of the surface in some examples may have led
to the erroneous supposition that the shell had been pierced through-
out by canals. Several statements in an interesting paper by Mr.
Meek, published in the Proceedings of the Academy of Natural
Sciences of Philadelphia for December, 1865, made Dr. Carpenter
desirous of re-investigating the subject; and consequently the shells
of several American and British Spirifers, resembling in shape our
well-known Spirifera cuspidata, were assembled and carefully ex-
amined. Dr. Carpenter publishes the results of his investigation
in the July number of the Annals and Mag. of Nat. Hist. for the
present year.
Some few years ago Professor Winchell discovered in the Carboni-
ferous rocks or “ Burlington Limestone” of Burlington, Iowa, a shell
undistinguishable in exterior appearance from our British examples
of Spirifera cuspidata, but which, from presenting certain peculiar
interior arrangements, had led him to propose for that and similarly
characterized shells the generic denomination of Syringothyris.' Now,
although Professor Winchell has stated that the shell of his genus
is fibrous and impunctate in all conditions and under high powers,
both Mr. Meek and Dr. Carpenter found very distinct perforations
in large portions of the shell of Syringothyris typa forwarded to
them by Professor Winchell himself.’
1 Proceedings of the Academy of Natural Sciences of Philadelphia, January, 1863.
2 Sex Notices oF Memorrs, at the end of this article (p. 315), for Mr, F. B,
Meek’s observations on the shell-structure of Syringothyris.
312 Davidson—On Syringothyris.
In 1863, as already stated, Professor Winchell describes (but does
not figure) his genus as ‘“‘a shell with an elongated hinge-line. Ven-
tral valve with a mesial sinus, a very broad area, and a narrow
triangular fissure closed towards the apex by an external convex
pseudo-deltidium ; beneath which, and diverging from it, is another
transverse plate connecting the vertical dental lamelle arched above,
and beneath giving off a couple of median parallel lamelle which are
incurved so as to nearly join their inferior edges, thus forming a slit-
bearing tube, which projects beyond the limits of the plate from
which it originates into the interior of the shell. A low median
ridge extends from the beak to the anterior part of the valve ; dorsal
valve depressed, without area, with a distinct mesial fold.” But in
order that the characters of the genus should be better understood, I
have figured in Pl. XIV. five drawings of Syringothyris typa, for which
I am indebted to Professor Winchell himself. Now, it has been
asked by Mr. Meek whether there may not occur at Millecent in
Ireland, and elsewhere, two closely similar but really very distinct
British types, confounded under the single specific denomination of
Sp. cuspidata ?—that is, one with a punctate structure, and another
without it ; and the examination of this question by Dr. Carpenter
has led him fully to adopt Mr. Meek’s conclusion, as I shall presently
explain.
Professor Winchell seems not to have been aware that the cha-
racters assigned by him to his genus had been already illustrated
and defined by Professor L. de Koninck in the Transactions of the
Royal Society of Liege for 1859; and, as I made at the time some
better and enlarged drawings from the Belgian specimens, I will
reproduce them here along with M. de Koninck’s original figure
(Pl. XIV. Figs. 6-9). These characters were found to exist in a
Belgian example of the Carboniferous Spirifera distans. Pro-
fessor Winchell adds: “Some difficulty exists in deciding on
the homology of the transverse plate and fissured tube which
characterize this genus (Syringothyris). In the ventral valve of
Merista, especially of the type of Camarium Hall, an arching lamella
arises from the basal portion of each dental plate, and the two unite
in the mesial line of the valve, forming a structure which Professor
King, before the separation of this genus, had styled the shoe-lifter
process—arched in front and attached to the bottom of the valve
behind. In Spirifera granulifera Hall, a horizontal tranverse plate
stretches across the middle of the beak of the ventral valve, con-
necting the dental lamellae where nearest approximated by their in-
ward curvatures—a structure which probably represents the pseudo-
deltidium of certain Spirifere, but not of Cyrtia. Beneath this plate,
the ventral medium septum assumes the form of a tapering cone,
resting with its base filling the cavity, and having the anterior part
of the upper side marked by a longitudinal groove or slit, while the
posterior part sends up a small vertical plate to the transverse plate
just mentioned. In Syringothyris the tranverse plate equally con-
nects the dental lamellae where most approximated, and is somewhat
arched upwards as in Merista, but it does not join the bottom of the
Davidson—On Syringothyris. 313:
valve as in that genus, nor is it connected with the median septum
as in Spirifera granulifera. Nevertheless, it would seem that the
three structures are modifications of the same elements.”
But what is the element thus modified? Prof. King suggested
that the shoe-lifter process of Cleiothyris concentrica is a modified form
of the ventral median plate; but the wide separation of its points of
origin from the normal position of this plate seems incompatible with
such a conclusion; while in Syringothyris and Spirifera granulifera
the median plate exists independently of the apparent homologue of
the shoe-lifter. Mr. Billings, whose observations are generally
marked by extreme sagacity, regards the shoe-lifter “as an abnormal
form of the pseudo-deltidium that occurs in some Spirifers.” This is
the relationship pointed out above; and there seem to exist good
’ morphological reasons for regarding the fistuliferous arching plate of
Syringothyris as a modified pseudo-deltidium. But to what does the
latter structure appertain? In Merista, Syringothyris, and certain
Spirifere its relation to the dental plates suggests that it may be an |
out-growth of those parts. The dental plates are amongst the most
heteromorphous structures of the ventral valve. From a normal erect
position, they become approximated along the ventral margins in
many Spirifere and other genera, while in Pentamerus, Orthasina,
and Camaraphoria, this approximation results in complete union, and
in Leptena in the formation of the saucer-shaped process of the
ventral valve. They also vary excessively in longitudinal develop-
ment. In many Spirifere, moreover, there is an evident indication
of a longitudinal folding of the dental plates, producing on one side
or the other a longitudinal laminar process, which, under an extra-
ordinary development, may coalesce with some neighbouring part.
While, therefore, the shoe-lifter process of Merista, and still more
the fistuliferous diaphragm of Syringothyris, may be but modifications
of the false inner deltidium of Spirifera granulifera, the three
structures, accidental among Palliobranchs, may be but mere out-
growths of the essential and typical parts known as dental plates.”
Such is Professor Winchell’s description of his genus Syrengo-
thyris, and it would be very desirable if any gentlemen who
possess good examples of Sp. cuspidatus would cut some of them as
shown in Fig. 11 of our Plate, so as to see how far they may agree
or differ from Syringothyris.
I would also refer the reader to some extremely interesting obser-
vations upon this subject recently published by Professor J. Hall,
in vol. iv. pp. 252-257 of his Paleontology of New York, and
from which I will here give the following extract. “If again we
look at the characters of Spirifera alta, an analogue or representative
of Spirifera cuspidata, we have many points of similarity with one or
more species in the rocks of the west and south-west (America)
which are usually referred to a higher position, The high area, and
the tranverse concave septum, which is not a true pseudo-deltidium,
allies it with Sp. teatus, in which we find similar features. In Sp. alta
there has, probably, been an external convex pseudo-deltidium, and
between this and the septum closing the fissure, there has been a
314 Davidson—On Syringothyris.
narrow space. This septum, which is an extension of the dental
lamella, has been thickened or expanded in the inner side, as
shown by casts of the ventral valve, and in several specimens there
is a narrow semi-cylindrical depression extending nearly to the beak
of the valve. In comparing this with Sp. textus, we find similar
conditions, or more properly an extension or amplification of the
same features. In that species there is a convex arching pseudo-
deltidium, though rarely preserved in the specimens; beneath this
there is a concave septum, and upon the inner face of this there is a
tubular callosity ; or, in other words, the inner lamine of the septum
become fistulose, and enclose a cylindrical or sub-cylindrical space,
which extends from the base of the septum to near the apex of the
valve. But more usually the lamine appear to be separated, and, ex-
tending inwards, are recurved, their edges sometimes joining to form
a tube, but more frequently, perhaps, the margin of each one is re-
curved upon itself, leaving the tube with a slit along the lower side.
In some instances, however, these extensions from the inner face of
the septum continue to the bottom of the cavity, and, joining the ex-
ternal shell, leave a quadrangular tube instead of a cylindrical one.
“Tf, in its full development, the presence of a septum and internal
tube be regarded as of generic value, then we have in Sp. alta the
same appendages in part, or in a partially developed condition, the
distinct tube only being wanting. But had we the means of ex-
amining the internal characters of the ventral valves of all the species
of Spirifers, we should, probably, find graduations from the. solid
filling of the rostral cavity, with a greater or less extension of shelly
matter in the form of a septum, in the fissure occupying a narrow
space in its apex, till we reached the development observed in S. alta
and S. teatus, etc.” It is, therefore, quite evident that much more
investigation with reference to the shell-structure of Spirifers, as well
as to their interior arrangements, will be required before they can
be all definitely divided into groups or genera. After a minute ex-
amination of several specimens of Spirifer, agreeing in shape with
Sp. cuspidata, and occurring at Millecent in Ireland, Dr. Carpenter
has found that in one example the entire shell was unquestion-
ably imperforate, while in others from the same locality certain
parts are unmistakeably perforated, although large patches remain
free ; and that in these last named shells, as seen in Fig. 11, the two
dental plates or lamelle are connected by a transverse plate, under
which is situated an incomplete tube, similar to the one described
by Professor Winchell as peculiar to his genus Syringothyris. In
the imperforate specimen, on the other hand, he finds the dental
lamelle to be unconnected by any transverse. plate, and the tube of
Syringothyris to be altogether absent.
The next point alluded to by Professor King has reference to
the Cyrtina heteroclita. It is quite true that in the Annals and
Mag. of Nat. Hist. for August, 1846 (not 1864) Professor King did
describe the septa and dental plates in this species, and did also
announce that the valves were distinctly perforated, and I much
regret having inadvertently omitted to state this in my Monograph,
»
~ Davidson—On Syringothyris. 315
_and for which omission I gladly apologise ; but at the same time it is
_also right to add that as early as 1841 both Mr. Bouchard and myself
were well acquainted with the internal characters of the ventral
valve of this species, as well as of C. Demarlii, for we had found
specimens showing the position of the septum and dental plates in
an excellent state of preservation in the Devonian quarries of
Ferques in the Boulonnais, and it was from those specimens that the
figures given in my Monograph were drawn. I was not, conse-
quently, indebted to Professor King for the information I possessed
upon this subject; but am exceedingly glad to learn that he has dis-
covered vestiges of spiral coils in Cyrtina heteroclita, as I had not
hitherto been so fortunate as to see them in any of the many specimens
of the species I had obtained. I may also here repeat that I still
adhere to the opinion expressed in my Monograph, namely, that, un-
til sufficient proof to the contrary can be adduced, I must continue
to consider C. carbonaria and C. septosa, as referable to the same
group as that typified by C. heteroclita and C. Demarlii, and that they
apparently all possess a perforated shell-structure.
EXPLANATION OF PLATE XIV.
Figs. 1-5. Syringothyris typa, from drawings communicated by Professor Winchell.
1. Dorsal valve (cast). 2. py. dorsal, v. ventral valves, 7. line in-
dicating the length and position of the dental plates. 3. Dorsal and
part of the ventral valve seen in profile. 4. Beak of ventral valve
partly destroyed; a. area, 7. dental plates or lamelle, ¢. tube in-
complete, 7. mesial ridge. 5. Section through a.p. The same
letters refer to same parts.
Figs. 6-9. Syringothyris ? distans, Sow., from the Carboniferous limestone of Visé, in
Belgium. 6. Part of the beak of ventral valve, seen from the
back, and after Professor L. de Koninck’s original figure, published
in 1859. 7, 8, 9. My drawings from the same specimen, enlarged.
7. Area and pesudo-deltidium. 8. The same viewed from the
opposite side, the shell forming the back of the ventral valve
being removed so as to show the shape and position of the dental
plates, as well as the position of the transverse plate and tube. 9.
The same seen in front; the area and pesudo-deltidium being
foreshortened.
Fig. 10. Syringothyris cuspidata, or typa? from Millecent, Ireland.
Fig. 11. 3 3 from same locality. A transverse section of the
beak having been cut through by Dr. Carpenter to show the
position of the dental plates, transverse plate, and incomplete tube,
as seen in the American specimens of Syringothyris typa. In this
specimen portions of the shell were perforated, while other parts
were free. Indications of the spiral coils may here also be
perceived.
ING@ SCE SS @ eb as Neen) Tees
adi, Sohal
I.—On toe Puncrare SHELL-sTRUCTURE or Srrivcoruyris. By
F. B. Merk, (from Silliman’s American Journal of Science and Arts,
May, 1867, p. 407).
AVING recently examined Professor Winchell’s types of his genus
Syringothyris, which he was so kind as to loan me, I find them all,
with the exception of two silicified specimens (showing no structure),
distinctly punctate. It is probable that Professor Winchell had hap-
316 Meek—Sheli-structure of Syringothyris.
pened to examine chippings from specimens not in a condition to
show the punctures. I have likewise ascertained, since the publica-
tion of my former paper on this subject, that Spirifer propinquus,
Hall, and S. Hannibalensis, Swallow, both nearly like S. euspidatus,
have a clearly punctate structure, and hence, probably belong to the
group Syringothyris.
I have just read a letter from Mr. Davidson, written to Mr.
Worthen, in which he quotes, from a letter to him from Dr. Car-
penter, a paragraph giving the results of his examinations of speci-
mens of Syringothyris, and of the same Irish shell examined by me
(and at one time supposed to be Spirifer euspidatus). These chip-
pings were sent over by Mr. Worthen, at Mr. Davidson’s request,
some little time back. Dr. Carpenter says he finds the Syringothyris
(that from Floyd Co., Indiana, I suppose), distinctly punctate, the
punctures being, as I stated, small and scattering. The chippings
from the Irish specimen sent over to Mr. Worthen, with the name
S. cuspidatus attached, Dr. Carpenter also found to be punctured,
though the punctures are not so clearly seen as in the other. Chip-
pings of S. subcuspidatus, Hall, sent by Mr. Worthen, he says are not
in a condition to show the structure.
At the time of writing Dr. Carpenter had evidently not received a
package of chippings I had sent him, containing specimens of S. sub-
cuspidatus, showing the punctures clearly. He says these examin-
ations of the structure of Syringothyris confirm its generic or sub-
generic differentiation, established upon other characters, and that the
Irish specimen, he believes, belongs to this group. He is still
confident, however, that the true S. cuspidatus is not a punctate
shell, which you will remember I had not supposed to be the case.
I never doubted or questioned the accuracy of Dr. Carpenter’s con-
clusions on that point, and there is no microscopist living in whose
results I have more confidence than in his.
I.—Ow toe Trrtiary Votcanic Rocks or tae British IsLanps.
By Arcuipap Gerxie, Esq., F.R.S., F.G.S.
[Abstract from the Proceedings of the Royal Society of Edinburgh, 1866-67,
vol. vi. p. 71.]
HIS paper was in continuation of the series of memoirs on the
volcanic rocks of Scotland previously read by the author before
the Society,! and contained the first portion of the results of a survey
of the western region, extending from the south of Antrim to the
north of Skye. The districts more especially dwelt upon were the
islands of Mull, Higg, and Staffa. After alluding to the writings of
previous geologists upon these tracts, more particularly to the dis-
covery by the Duke of Argyll of Tertiary leaves under basalt at
Ardtun Head, in Mull, the author remarked, that up to this time the
great mass of volcanic rocks in the Western Islands has been usually
regarded as of Oolitic age—an opinion in which he himself had
shared. His object in the present communication was to show that
1 See Proceedings, iv. 309, 453, 582, and Transactions, vol. xxii. 633. ©
Getkie—British Tertiary Volcanic Rocks. 317
as regards Mull and the adjoining islets this opinion was erroneous,
that the enormous volcanic accumulations of these islands belonged
in reality to the Miocene period, and that, in all likelihood, the long
chain of basaltic masses, extending from the north of Ireland along
the west coast of Scotland to the Faroe Islands, and beyond these to
Iceland, was all erupted during the same wide interval in the Ter-
tiary period.
The nature of the volcanic products was first sketched. It was
shown that the two great classes of recent lavas—the basaltic and
the trachytic—were “well represented among the Western Islands,
and that the basaltic series was on the whole the older, since it was
found to pass under massive sheets of pale grey and blue claystones,
clinkstones, and porphyries belonging to the trachytic group. In
addition to these lava-form rocks, masses of coarse volcanic agglome-
rate occurred, along with beds of tuff and peperino.
The manner in which these various volcanic rocks occur in Mull
and Kigg was next described. It was shown that the leaf-beds of
Ardtun, which are known by their fossil contents to be of Miocene
age, lie near the bottom of the whole volcanic series, and that above
them comes a series of trap-beds between 38,000 and 4,000 feet in
thickness. Throughout this enormous mass of bedded igneous rock,
layers of ash, often abounding in Chalk-flints, are interstratified, and
in one part of the cliffs of Inimore of Carsaig a bed of flints twenty-
five feet thick lies between the dolerites. Thin lenticular seams or
nests of coal likewise occur, but these only occupy small pond-like
hollows of the original surface of the trap beds, and are overlaid
directly with trap. They are sometimes excellent in quality, and
occasionally three feet in thickness; but they rapidly die out-in
every direction. There is thus no probability that the Tertiary coal
of the Western Islands will ever come to be of commercial im-
portance.
Proofs of the long continuance of volcanic action among these
islands are afforded by the great thickness of the successive sheets
of igneous matter, which in one mountain alone—Ben More—reach
a depth of 3,185 feet without revealing either the actual bottom or
top of the series. Another and striking piece of evidence on this
subject is given by the well-known Scuir of Higg. That island
consists of nearly horizontal sheets of dolerite, like those of Mull,
resting unconformably upon Oolitic rocks. After their eruption,
they must have been long exposed to the wasting agencies of the
atmosphere. A valley was cut out of them, and its bottom was
watered by a river, which brought down coarse shingle and sand
from the distant Cambrian mountains of the north-west. These
changes must have demanded a lengthened lapse of time, yet they
took place during an interval in the volcanic history of the island.
The igneous forces which had been long dormant broke out anew,
and poured several successive coulées of vitreous lava down the river-
bed. In this way the channel of the stream came to be sealed up.
But the same powers of waste which had scooped out that channel
continued their operation, The hills which had bounded the valley
318 Geikie—British Tertiary Volcanic Rocks.
crumbled away, and the lava-currents that filled the river-bed, being
much harder than the surrounding rocks, were enabled in great
measure to resist the degradation. Hence the singular result now
appears that the former hills have been levelled down into slopes
and valleys, while the ancient valley occupies the highest ground
in the neighbourhood, and its lava-current stands up as the well
known precipitous ridge of the Scuir of Higg. The gravel and drift-
wood of the old river are still to be seen under the rock of the Scuir.
The author then proceeded to point out the possible connection
between these Tertiary volcanic rocks and the metamorphism of
different parts of the West Highlands. He showed that in Mull,
under Ben More, the volcanic rocks themselves give signs of having
been subjected to a process of metamorphism, and that they are
associated there with masses of syenite, like those of Raasay and
Skye. Macculloch pointed out that the syenite of the two latter
islands was later than the Secondary rocks of that district ; and there
now seems to be a strong probability that it will turn out to be of
Miocene age. Parts of that syenite are true granite, while the Lias
around it has suffered an extensive metamorphism. It will be an
important addition to our knowledge of the history of metamorphic
action, if the alteration of the Secondary rocks of the Hebrides is
eventually shown to be connected with the evolution of volcanic
rocks during the Miocene period.
The wide extent to which the British Islands were affected by the
Miocene volcanos of the west was then referred to. That extent is
not to be measured by the area at present covered with Tertiary
volcanic rocks, nor even by the area which these rocks may have
originally overspread ; but from which subsequent denudation has
removed them. From the great volcanic ridge running through
Antrim and the Western Islands, thousands of trap-dykes diverge
in a south-easterly direction. They become fewer as the distance
from that bank increases, yet they extend as far as the coast of
Yorkshire. No single dyke, indeed, has been traced across the
country from sea to sea; but there can be little doubt that they all
belong to one series. They cut through all the formations up to and
including the Chalk, and they likewise traverse the older portions of
the Tertiary volcanic rocks. They must thus be of Tertiary age, and
belong to that series of igneous masses described in the present
paper. They do not usually run along lines of fault; on the con-
trary, they are found to cross faults of fifty fathoms and upwards
without being deflected. Their evenness and parallelism show that
they must have ascended through fissures prepared for them by
subterranean movements. Thus we learn that in Tertiary times the
greater part of Scotland, the north of England, and the north of
Treland, were cracked by earthquakes, and that liquid lava rose
through the hundreds of parallel rents, perhaps in some cases
actually reaching the surface.
The last section of the paper was devoted to an account of the
denudation of the Tertiary volcanic rocks. It was shown that wide,
deep, and long valleys have been excavated out of the horizontal
Coemans—Fossil. Flora of Hainault. 319
trap-beds ; that these rocks have sometimes been so wasted away
that only huge detached pyramids of them are left, as in the case of
Ben More, Mull; that the volcanic bank has been worn down into
detached islands often miles apart; and that from the fact of so
many trap-dykes reaching the surface, even at a distance of more than
two hundred miles from the main mass of volcanic rock, the general
superficies of the country must have undergone a very extensive
amount of denudation since the Miocene period. These changes
point to the passing of an enormous lapse of time, and help to teach
us that, though in a geological sense, the Miocene age belonged to a
recent part of the earth’s history, it is nevertheless separated from
our own period by an interval too vast to be realised by the mind.
IJJ1.—Derscrietion DE LA Fiore FossiLE DU PREMIER ETAGE DU
TERRAIN CRETACEE DU HarnavtT, PAR HucGENE Conmans. Bruxelles,
1866.
HIS short but interesting memoir on the fossil flora of the Creta-
ceous strata of Hainault is well deserving the attention of the
student of fossil botany. The remains found at La Louviére consist
of many cones, generally well preserved, fragments of wood, pieces
of resin, and masses of lignite and small roots, completely car-
bonized ; and their arrangement indicates a tranquil deposit. The
striking feature of this flora is that it appears composed almost
exclusively of Conifere and Cycadea, and like other Cretaceous floras
does not possess any species common to other floras of the same
period, and differs entirely from that of Aix-la-Chapelle, only thirty
leagues distant; not one of the twenty species of Conifere found :
there being identical with any of the eight species described from
La Louviére,—the flora of Aix-la-Chapelle presenting, according to
M. Coemans, a younger aspect, in containing some species of Sequoza,
and not any Cycad. The recent addition of a Cycad to the British
Cretaceous flora is interesting.
M. Coemans considers that the fossil flora of Hainault contains
types or intermediate forms which connect certain genera of Conifera;
thus, his Pinus Corneti is intermediate to Abies and Cedrus; the P.
Andrai_ connects Strobus with Pinaster; and the Pinus Heeri and
depressa form a transition from Cembra to Strobus. At page 17
M. Coemans retains Zamites macrocephalus and Z. ovatus, both which
Mr. Carruthers has shown to belong to Pinites (Guo. Mac., Vol. III.
p- 586), and are not Cretaceous, but Lower Hocene fossils.—J. M.
IV.—NotEs on some Triassic Crustacea From Styria. By
Professor A. E. Reuss, For. Corr. G. 8.
[Proceed. Imp. Geol. Instit., Vienna, January, 15th, 1867.]
ASPIDOCARIS TRIASSICA, Reuss, from the inferior Triassic
limestone west of Aussee, north-west of Styria, occurs as im-
pressions with fine concentric striz, not unlike the leaves of
Sayittaria, with a triangular notch produced by the separation of a.
320 Laube—Fossils of the Brown Jura.
rostral portion originally limited by furrows, as in the genera Pelto-
caris, Salt., and Discinocaris, Woodw. It must be remarked that
all other forms of Phyllopods, the actually living genus Apus excepted,
are Paleozoic. Aspidocaris, Reuss, stands next to Discinocaris,
Woodw.
Halycine elongata, Reuss, from the same limestone,—a dorsal cara-
pace badly preserved. The three or four species of the Pcecilopod
genus Halycine at present known, all belong to the Conchiferous
Limestone, or to the Inferior Keuper-
Cythere fraterna, Reuss, from the shales of Raibl Carinthia, which
also abound in plants, Decapod Crustacea, and fishes. Isolated valves
of an Ostracod, nearly related to Cythere Richteriana, from the
Zechstein, are of some interest as being the earliest remains of this
Crustacean stated to occur in the Alpine Trias.—[ Count M. ]
V.—Die BIVALVEN UND DIE EXCHINODERMEN DES BRAUNEN JURA VON
Bauin. By Dr. Gustav C. Lausz. Wien, 1867.
HLESE two papers by Dr. Laube are in part a continuation of the
paleontological researches commenced by Professor H. Suess,
on the fossils of the Brown Jura of Balin, in Poland. The papers
contain descriptions and carefully prepared illustrations of the Echino-
derms and bivalve shells found in the Lower Oolite of that locality,
and are interesting as showing the wide range of some species of
the Oolitic fauna. Five species of Hehinoidea, belonging to the genera
Clypeus, Collyrites, Echinobrissus, Hyboclypus, and Holectypus, are
common to Balin and the Lower Oolites of England. Of the Conchi-
fera about seventy species from Balin have been identified by Dr.
Laube as occurring in the Inferior and Great Oolite and Cornbrash of
England. The curious genus Elignius of Deslongchamps is repre-
sented by two species, and under Cardiodonta of Stolitczka, are
included certain forms placed by Sowerby and Minster in Isocardia.
The genera Tancredia, Sowerbya, and Gresslya are also represented.
J. M.
VI.—Nortzs on 4 New Genus or Fossit Crustacea. By F. B. Mzex.
NEW Crustacean, from the Coal-measures of Illinois, was
described in 1865, by Messrs. Meek and Worthen, under the
name of Belinurus Dane; it differs, however, in some respects from
the characters usually assigned to that genus. Having since seen
the paper by Mr. H. Woodward on the Structure of the Xiphosura
(Quart. Journ. Geol. Soc., Vol. xxiii.), in which that group is now
divided into three genera—Mr. Meek has been led to refer his
Belinurus Dane to a new genus, holding an intermediate position
between Belinurus and Prestwichia; for this he proposes the name
Euproops, in allusion to the anterior position of its eyes. ‘This form
is at once distinguished from the now restricted genus Pelinurus, by
its anchylosed abdominal segments and the anterior position of its
éyes, as well as by the more oval or sub-circular outline of its abdo-
men. From Prestwichia, with which it more nearly agrees in general
Reviews—Relique Aquitanice. 321
form, as well as in its anchylosed segments, it differs remarkably in
having the area enclosed by its eye-ridge (glabella) comparatively
small, and of a quadrangular form, with the eyes situated far for-
ward at its anterior lateral angles.—Amer. Jour. Science, and Arts,
May, 1867.
Sede IG WSs
I.—Reuiquiz AQuitanica#: BEING CONTRIBUTIONS TO THE ARCHZO-
LOGY AND PALHONTOLOGY OF PERIGORD, AND THE ADJOINING PRo-
VINCES OF SoUTHERN France. By Enovarp Larret and Henry
Curisty, Edited by Professor T. Rupert Jonus, F.G.S., etc., ete.
(Third Notice.)
N referring again to this important work we have only to state that
Part IV. maintains the high character for which the three pre-
vious Numbers were distinguished. The six plates now issued
are devoted to figures of stones, used as mortars, to flint cores from
which flakes have been struck, and to a further series of cleverly-
carved Reindeer-horn weapons. ‘The figures of animals, engraved
upon some of these remains, possess great merit; especially we would
notice the carving of a deer on B. PI. vii. et viii., fig. 6.
Chapter III. is devoted to a notice of the chief Geological features
of the valley of Vezere, and the bordering country, accompanied by a
sketch-map and section of that valley.
As suggestive of the origin of flint in the Chalk of the Dept.
de la Dordogne, the Editor considers (p. 82) that it is only so much
of the Cretaceous stratum silicified.
“The particles of Polyzoa, the Orbito/des, and other organic remains
being still in place, and retaining their characteristic structures.
Even fish-teeth (Otodus) have been altered into flint except a thin
external pellicle.” < There is also flint showing a further progress
of mineralization, in which the constituent organic remains of the
limestone have been more and more removed from sight by the
increased homogeneity of the pseudo-amorphous silex, as is usually
the case with the flint of Northern France and England.”
That some flint may have been so formed is possible, but it is
equally probable that many, if not all, the flint nodules and bands
occurring in the Chalk and even chert, owe their origin to a segre-
gation of silicia, previously held in solution—around some nucleus—
such as a silicious sponge, or other organic remain, which almost
invariably accompanies these bodies.
We imagine the author would not include in his list of pseudo-
morphic silicious replacements, the fissures filled with flint in the
Chalk as at Pegwell Bay, in Kent, and Rottingdean, near Brighton,
and many other localities, which are not unfrequently lines of fault.
These veins of flint seem to justify one in attributing their occurrence
to the simple infiltration (without replacement) of the Silica.
VOL. IV,—NO. XXXVII. 21
322 Reviews—Delesse’s and De Lapparent’s Revue de Geologie.
I.—Gerotocican Rusnarcues in Curna, Monconra, AND JAPAN,
purInG 1862-1865. By Rapuarn Pumpntiy, 4to. pp. 144.
1866. Nine plates. Smithsonian Institution, Washington.
HE present memoir contains a full Report of the author’s obser-
vations, to which we have already alluded in a former Number
of this Journal (see Gronocican Magazine, Vol. II. p. 507.)
The most important chapters are those which relate to (1), The
Geology of the Basin of the Yangtze Kiang; (2) The Geology of the
Route from the Great Wall to the Siberian Frontier; and (3), On
the General Geology of China proper. Mr. Pumpelly gives a hypo-
thetical map of the structure of China, from which it appears that
more than two-thirds of the whole area of the country is occupied by
Coal-measures, which, yielding both Anthracite and Bituminous coal,
have been extensively worked for ages, and appear, from the Plant-
remains, to be of Mesozoic date.
The six characteristic plants, figured on Plate ix., resemble those
of the European Oolitic Flora, and differ from *the Indian and
Australian, in the absence of the genera Phyllotheca and Glossopteris.
The names of figs. 4 and 5, on the plate, and also in the text (pp.
122-3) appear to have been reversed.
Chapter IX. contains Notes on the Geology of the Island of Yesso,
and Chapter X.is devoted to a list of all the useful minerals found in
China, with their localities, and in the Appendix is given analyses
of Chinese and Japanese Coals by Mr. J. A. Macdonald, of Yale
College.
II.—Barranpe’s Bonemian Cepuaroropa. Cephalopodes Siluriens
de la Bohéme. Prague et Paris, 1865-1867.
js cea Text of this great work has now appeared. The two volumes
of plates, previously published in 1865, were noticed in the
GxorocicaL Magazine, Vol. III. p. 32. The present volume contains
the description of 447 specific forms, belonging to 16 genera, ar-
ranged under the families Goniatide and Nautilide, and is only the
first part of the studies of M. Barrande on the Silurian Cephalopoda, of
Bohemia. The second part will include the genus Orthoceras, and.
other straight shells which can be associated with this type, either as
sub-genera or distinct genera, such as Gonioceras, Endoceras, Tretoceras.
M. Barrande reserves for the end of this work his general observations
on the study of the Palzeozoic Cephalopoda, which will no doubt be
treated by him in a similar manner to that which has rendered his
study of the Silurian Trilobites so exceedingly valuable to Palzon-
tologists.
IV.—Revve pe Gxonociz pour tes Annies, 1864 er 1865. Par
MM. Dertzssz nr De Lapparent. Paris, 1866.
HIS useful work has now arrived at the fourth volume, and fills up
a lacuna much wanted in France, as it comprises a general
resumé of the most important works published during the preceding
Reviews—Smyth’s Lectures on Mining. 323
year, so that the series presents us with the history of the progress
of Geology since 1860. Its value is enhanced by the methodical
arrangement of the subjects, as well as by the classified index, and
the present volume is further enriched by memoirs forwarded direct
to the Editors, and not previously published. The subjects are
arranged under four heads. ‘The first part comprises notices of
periodical works on geology, and geological and agricultural maps,
agencies at present in operation, both external and internal, and
mountain systems. The second part includes the general characters
of rocks subdivided under different heads, Meteorites, production of
Metamorphism, and the age of Eruptive rocks. The third part treats
of Palzontdlogy and the succession and character of fossils found
throughout the stratified rocks as derived from the memoirs cited,
and the last part embodies the geological researches and descrip-
tions of different countries, arranged geographically, and including
some important tables of strata in certain districts. From the selec-
tion and conciseness of the subjects, the work will prove eminently
useful to the geologist, and highly creditable to the care, judgment,
and energy of the editors.—J.M.
V.—Lectures on Muinine.—The reports of the lectures by
Professor W. Smyth, on practical mining, are now concluded in the
Mining Journal, and altogether form a valuable series of papers on
some of the guiding principles of the most extensive subjects of
mining, and will materially assist the student in systematising the
studies he may hereafter take up. In the latter part of the course
the following subjects were treated of:—The various methods of
working coal, as the pillar and stall, and long-wall workings, and
their advantages ; the methods in vogue for working seams of un-
usual thickness; the removal and conveyance of minerals from the
workings to the shaft; the raising of minerals, and the difference
of use made of shafts, in metalliferous mines and collieries; the use
of pumps and their construction ; the ventilation of mines, and the
various means adopted for distributing air through the workings ;
and lastly, the different processes used in the dressing and preparation
of the ores.—J.M. )
REPORTS AND PROCHHDINGS:
——_———<—
OpontoLogicAL Society or Lonpon, June 3rd, 1867.—“‘ On the
Dental characters of Genera and species, chiefly of Fishes, from
the Low Main Seam and Shales of Coal, Northumberland.” By
Professor Owen, F.R.S., etc., ete.—The author having received, from
time to time, sections of coal from the ‘ Low Main Seam,’ or from the
shales overlying that seam, (collected and prepared for microscopic
examination, by T. Craggs, Hsq., of West Cramlington and Gates-
head, Northumberland), he found them to consist of portions of jaws
and détached teeth, chiefly of minute Fishes, which from their non-
324 Owen—New Genera of Fishes, §c.,
descript character, he concluded, after careful study and comparison,
to be new to Carboniferous Paleontology.
Professor Owen has proposed for them the following generic and
specific appellations :—
Genus I.—Dittodus, Owen (urs, twin or double, d8ovs, tooth).
Species 1.—Dittodus parallelus, Owen.
These teeth have the peculiarity of a double crown, rising from
a common base; the hard dentine of one crown being continued
at the side of the base into the corresponding tissue of the other;
thus the two crowns are organically connected together, like the
Siamese twins.
Professor Owen considers it highly probable, from the character of
the osseous tissue of the portion of jaw preserved with these twin-
teeth, that the genus is referable to the Class of Fishes.
Species 2.—Dittodus divergens, Owen.
In this species the two crowns are more divergent from their
common base; they differ in their shape and proportions (being
shorter and broader); and also in structure.
Genus II.—Mitrodus, Owen (yitpa, mitre, ddovs, tooth).
Species 1.—Mitrodus quadricornis, Owen.
This tooth sends up four subequal conical crowns from the
common osteodentinal base, and its name is derived from its re-
semblance to an ancient mitral diadem.
Genus III.—Ageleodus, Owen (ayédn, crowd or cluster, ddovs,
tooth).
Species 1.—Ageleodus diadema, Owen.
In the tooth here described, no fewer than a dozen subequal
conical dentinal crowns are developed from a common osteo-dentinal
basis.
Genus IV.—Ganacrodus, Owen (ydvos, shine, axpos, point, odovs,
tooth).
Species 1.—Ganacrodus hastula, Owen.
Several of these “enamel-tipped spear-teeth ” have been obtained
by Mr. Craggs from the shale overlying the “ Low Main Seam” of
Coal, at West Cramlington. The curious manner in which these
teeth are tipped with enamel, at once arrests attention, and the
author observes that he had not before met with any similar tooth in
the whole range of his odontological researches.
Genus V.—Ganolodus, Owen (yavos, shine, édos, whole, ddovs,
tooth).
Species 1.—Ganolodus stcula, Owen.
These teeth offer points of resemblance to the Sauroid type which
are wanting in the previous genus; they are amongst the more
common forms met with by Mr. Craggs in his prepared coal-sections.
Genus V.—Mioganodus, Owen (pelwv, less, yavos, shine, o00Us,
tooth).
Species 1.—Mioganodus laniarius, Owen.
The section of this tooth resembles an incompletely-formed canine
of a young mammalian carnivore, save that the enamel of the crown
is not present in mammalian proportions and structure.
From the Coal-Measures. S25)
Genus VI.—Aganodus, Owen, (a, priv. yavos, shine, d5ous, tooth).
Species 1.— Aganodus apicalis, Owen.
This genus seems characterised by the absence of the enveloping
‘layer of enamel observable in Ganolodus, etc., and there is also a
different disposition of the dentinal tubules.
Species 2.—Aganodus undatus, Owen.
The form and structure of this tooth differs from that of Ag.
apicalis in a degree which induced the author to present it under
a distinct specific name.
Genus VII.—Pternodus, Owen (arépva, heel, ddovs, tooth).
Species 1.—Pternodus productus, Owen.
Some of the small teeth, with crowns of unvascular dentine
uncoated by ganoine, have the hinder part of the base drawn out
like a heel; they differ from the type Aganodi in a more gradual ~
basal expanse of the pulp-cavity, and in the absence of the thin
platform of hard osteodentine which supports in them the crown
of the tooth, and divides it from the ordinary bone of the jaw.
Genus VIII.—Sagenodus, Owen (cdynvn, seine, ddovs, tooth).
Species 1.—Sagenodus inequalis, Owen.
The teeth of this genus offer a type of structure akin to the extinct
Dictyodus and the existing Sphyraena, appearing as tooth-like pro-
cesses of the jaw, of which they continue the structure with little
modification.
Genus IX.—Characodus (yapae, a pointed stake, ddovs, tooth).
Species 1.—Characodus confertus, Owen.
The teeth of this genus are of the Dictyodont type of structure.
Genus X.—Ochlodus, Owen (oyAos, crowd, ddovs, tooth).
Specie 1.—Ochlodus crassus, Owen.
Close set as are the teeth in parts of the dental series of the last-
mentioned genus, they are more crowded in the fragment of the
alveolar part of a jaw of this genus for which the author proposes
the name Ochlodus crassus.
Genus XI.—Oreodus, Owen, (opeus, mule, ddovs, tooth).
Species 1.—Oreodus. robustus, Owen.
(Probably a species of Aganodus, allied to 4. wndatus).
Genus XII.—Gastrodus, Owen (yaornp, belly, ddovs, tooth).
Species 1.—Gastrodus prepositus, Owen.
Of this genus there have been discovered two portions of denti-
gerous jaw and of detached teeth. All the most complete teeth
show a large pulp-cavity, inclosed by a thin wall of unvascular
dentine, and in no case does any tissue, like osteodentine, encroach
upon the pulp-cavity. In this respect the teeth resemble those of
Dendrerpeton, and the Frog, and differ from the teeth of most Fishes.
The tissue of the dentine, as well as that of the jaw-bone, bears
the same resemblance to those in the Batrachia cited.
After carefully and minutely describing the details of the struc-
, ture of this genus, Professor Owen infers that we have in Gastrodus
evidence of a minute air-breathing Batrachian, of the age of the
lower Coal-measures of Northumberland.
326 Geological Society of London.
If this inference be correct, the author suggests that it may lead to
the determination of the nature of the medium in which these minute
fishes, of the size of Minnows or Sticklebacks, lived, apparently
associated with Batrachia, and now entombed in beds composed of
the carbonized remains of land-plants and semi-aquatic vegetation.
With regard to the genera and species here indicated, Professor
Owen does not object to the possibility that one or more forms of
teeth may have belonged to different parts of the same mouth (e.g.
Mitrodus and Ditiodus) ; the author considers, however, that it will
afford most facility to future investigators of these Coal-remains,
if they are able definitely to express the nature of the fragment they
may have discovered by referring it to one or other of the forms here
described.
Professor Owen, in his paper, treats at considerable length of
the form and histology of each genus and species recorded, and a
series of fifteen elaborately-prepared plates have been drawn by
Mr. Tuffen West for its illustration. The whole paper forms one of
the unpublished Chapters for a Second Edition of Professor Owen’s
“‘ Odontography.”
GxEoLocican Socimty or Lonpon.—I. May 8, 1867.—Warington
W. Smyth, Esq., M.A., F.R.S., President, in the chair. The
following communications were read:—1. « On new specimens of
Eozoon.” By Sir W. E. Logan, LL.D., ete.
Amongst several additional specimens of Hozoén which have been
obtained during recent explorations of the Canadian Geological
Survey, is one which was found last summer by Mr. G. H. Vennor,
in the township of Tudor, county of Hastings, Canada West. It
occurred on the surface of a layer, three inches in thickness, of dark-
grey micaceous limestone, or calc-schist, near the middle of a great
zone of similar rock. This Tudor limestone is comparatively un-
altered, and, in the specimen obtained from it, the skeleton of the
fossil, consisting of white carbonate of lime, is imbedded in the
limestone without the presence of serpentine or other silicate, a fact
which the author regarded as extremely favourable to the view of
the organic origin of Hozoén. Sir William Logan also described the
nature and relations of the rocks of other localities which have
recently yielded Hozoén, especially Wentworth, Long Lake, and
rie St. Pierre.
“ Notes on Fossils recently obtained from the Laurentian rocks
of islet and on objections to the organic nature of Hozoon.” By
J. W. Dawson, LL.D., F.R.S., F.G.8.
The first specimen described in this paper was the one from Tudor
referred to in the previous communication. Its examination had
enabled Dr. Dawson to state, that in it the chambers are more con-
tinuous, and wider in proportion to the thickness of the septa, than
in the specimens found elsewhere, and that the canal-system is more
delicate and indistinct. Without additional specimens the author
could not decide whether these differences are of specific value, or
depend on age, variability, or state of preservation; he therefore
Geological Society of London. 327
referred the specimen provisionally to Hozoén Canadense, regarding
it as a young individual, broken from its attachment, and imbedded
in a sandy calcareous mud. Its discovery afforded him the hope
that the comparatively unaltered sediments in which it has been pre-
served, and which have also yielded worm-burrows, will hereafter
still more largely illustrate the Laurentian fauna. After giving
short descriptions of new specimens from Madoc, and from Long
Lake and Wentworth, Dr. Dawson discussed the objections of Prof.
King and Dr. Rowney to the view of the organic nature of Eozoén,
and stated that those gentlemen had failed to distinguish between
the organic and the crystalline forms, as was especially illustrated
by their regarding the veins of chrysotile as identical with the tubu-
lated cell-wall of Hozoén.
3. “On Subaérial Denudation, and on Cliffs and Escarpments of
the Chalk and the Tertiary strata.” By W. Whitaker, Hsq.. B.A.,
F.G.S.
From the fact that escarpments differ from cliffs in all their chief
features, the author inferred that the two could hardly result from
the same action; but that whilst the latter were made by the sea, the
former seem to have cut out by subaérial agents.
The chief contrasts between the two kinds of ridges are :—
(1) Escarpments always run along the strike. Cliffs rarely do so.
(2) The bottom of an escarpment is not at one level throughout.
That of a sea-cliff is.
(3) At the foot of an escarpment one does not find a breach or
other trace of the action of the sea, but often such débris as would
be left by a slow and quiet denuding power.
(4) Two escarpments, facing the same way, often run near and
parallel to one another for many miles. Not so with cliffs.
(5) The ridge of an escarpment is a nearly even line, and forms
the highest ground of the neighbourhood. The top of a cliff is often
very uneven and bordered by higher ground.
From an examination of escarpments of the Chalk and of the
Tertiary beds, it was shown that though at first sight they might
seem like old lines of cliff, yet a little study would destroy the
fancied likeness, and it would be found that they are quite unlike
cliffs in the same beds; for though, from their winding outline, these
ranges of hills might remind one of some irregular coast, caused by
rocks of different hardness wearing away at different rates, they
have little in common with the far more even coast that is formed
where there is but one kind of rock.
It was then pointed out that along the present coast, the sea is
not the only force engaged in the work of destruction, but that it is
- largely helped by atmospheric agents (the latter acting from above
downwards, to detach and hurl down masses of rock, which the
former, acting horizontally below, pounds down and sweeps away);
and it was inferred that the joint action of the two kinds of force
had a far greater effect than either alone.
In conclusion, it was argued that as deposits of great thickness
(such as the Wealden beds) had been made by rivers, it must be
328 Geological Society of London.
admitted that, allowing for waste, still greater masses of rock had
been destroyed by streams and by subaérial agents generally. The
denuding power of the sea, however, was by no means denied, but
it was allowed that as marine deposits much exceed in quantity
those of freshwater origin, so the great denudations, the planings-
down of vast tracts, of which examples are given by unconformities,
have been worked out by the action of the sea; but that, on the
other hand, the far smaller denudations, and comparatively trifling
irregularities of the surface (our hills and valleys) have been worn
out by the long continued action of rain, rivers, and ice.
II. May 22, 1867.—J. Carrick Moore, Esq., M.A., F.R.S., Vice-
President, in the chair. 1. “On the Bone-caves near Krendi, Zeb-
bug, and Melleha, in the Island of Malta.” By Captain T. A. B.
Spratt, R.N., C.B., F.B.S., F.G.S.!
The Krendi (or Mahlek) Cavern is situated on the south coast of
Malta. The flooring consisted of two distinct deposits, the lower
being a stratum composed of a hard stalagmitic clay with rounded
pebbles, and containing teeth and bones (unworn) of the Hippopo-
tamus (H. Pentlandi). 'The upper stratum, also a stalagmitic deposit,
contained bones of the Myoaus Melitensis, and of birds with some
recent land-shells.
The Zebbug Cavern, in the interior of the island, was, when dis-
covered, filled with sandy clay containing subangular fragments of
the rock, and bones of at least two species of elephant, comprising
a complete set of the teeth and tusks of the pigmy elephant, repre-
senting animals in every stage of growth, and part of the tusk of a
much larger elephant. No remains of Hippopotamus were met with
in this cavern; but a few bones of Myoaus (2 species), of birds, and
of a Chelonian, were discovered in it.
The Melleha Cavern, at the north end of the island, contained a
deposit with remains of the teeth and bones of the Hippopotamus
only, and seemed, therefore, to represent the lower stratum of the
Krendi Cavern.
From the fact that the deposits containing remains of the Hippo-
potamus were so distinct from those including the Elephant-remains,
Captain Spratt inferred that these two mammals belonged to distinct
geological epochs, the elephant being the more recent.
As Malta and Gozo were probably elevated above the sea at the
close of the Miocene period, it is very possible that the caverns,
formed by the long action of the sea upon its cliffs, may contain the
relics of animals of more than one, if not of each subsequent geolo-
gical period.
In respect to Dr. Leith Adams’ discovery of remains of the
elephant in scattered débris of subangular fragments and red earth,
filling fissures and hollows in various parts of Malta, Captain Spratt
stated his opinion that the phenomena were produced by a “wave
! For an account of the Maltese Bone Caverns, and the Physical Geology of the
Island, with Map and Sections, see Gzonoaican Magazine for April, 1866, Vol. III.
p. 140, Pl. VIII. and IX,
Geological Society of London. 329
of translation,” resulting from a sudden subsidence of the island
below the sea at a very recent geological period, of too short a dura-
tion, however, to allow of any purely marine deposit being formed.
Captain Spratt discussed the evidence, afforded by soundings, of
the former connexion of Malta with Europe and Africa, by land that
must have served as a means of migration to the cave-fauna. The
submerged lands are indicated by the “‘ Adventure Bank,’ between
Tunis and Sicily ; and by the “Medina Bank,” a ridge connecting
the south-east of Malta with Tripoli. An upheaval of about 200
fathoms would render both banks dry, with the exception of one or
two narrow channels, which would not impede the larger animals
from passing from one continent to the other at the seasonable
times for migration.
2. “On the Lower Lias of the North-east of Ireland.” By Ralph
Tate, Hsq., A.L.S., F.G.S.
The author described the Lias of Ireland as consisting of (1) the
Avicula-contorta series, including a well-developed zone of Avicula
contorta and the White Lias; (2) the Lower Lias, embracing the
equivalents to the zone of Ammonites planorbis, A. angulatus, and
A. Bucklandi of Great Britian ; and a fourth zone (that of Belem-
nites acutus), representing that portion of the Lower Lias superior
to the zone of Ammonites Buckland.
Mr. Tate stated that the principal portion of the Lias belongs to
the zone of Avicula contorta, and that the greater portion of the
Lower Lias is comprised in the zone of Ammonites angulatus. The
remarkable and isolated mass of metamorphosed Lias at Portrush
was referred to the “ Planorbis series.”
3. “On the fossiliferous development of the zone of Ammonities
angulatus in Great Britain.” By Ralph Tate, Esq., A.L.S., F.G.S.
In this paper the author recorded the discovery of a fauna
hitherto imperfectly known in this country, characterizing beds
below the Limestone-series of the Lower Lias. It is exceedingly
rich in fossils: Cephalopoda are few in number (about 8 species) ;
Gasteropoda are various, numerous and characteristic, there bemg
about 50 species, the majority of which are new to Great Britain ;
the Corals are abundant and peculiar.
The zone of Ammonites angulatus was stated to occur at various
places in Ireland; at Marton, Lincolnshire; in Warwickshire ; in
North Gloucestershire; at Brocastle and Sutton, in Glamorganshire ;
and in Dorsetshire.
The author further communicated the results of a critical exami-
nation of the Sutton stone fossils—which are (1) that the majority
of the species are well-known Liassic forms of the continent, and
oceur in other parts of Great Britain; (2) that they incompletely
represent the fauna of the zone of Ammcnites angulatus; and (8)
that the Sutton Stone is lithologically and paleontologically identical
with the ‘“Calcaire de Valogne,” the stratigraphical relations of
of which have been well determined.
4. On the Rhetic Beds near Gainsborough.” By F. M. Burton,
Esq., F.G.S.
330 Norwich Geologieal Society.
Beds of the Rheetic series were stated to occur at Lea, two miles to
the south of Gainsborough, and were described as consisting of more
or less indurated and highly micaceous sandstones, alternating with
black shaly clays, and containing two bone-beds.
The fossils are very abundant, and are those which are usually
met with in the ‘Avicula-contorta” zone of other parts of Great
Britain. A fragment of the edentulous portion of the right ramus of
the lower jaw of a Pliosaurus was found in the lowest bed, lying
on the blue Keuper Marl. Two interesting additions to the verte-
brate fauna of this series are Trematosaurus Alberti, and Lepidotus
Giebeli ?
The author pointed out the correlation of these beds with those at
Aust Cliff and other well-known localities in England, and their
probable connexion with similar deposits in Ireland and on the con-
tinent; he concluded by defining the surface-extent of this the
most northern English deposit of Rhetic age as yet discovered.
Norwich Gzxonocican Socrrty.—Monthly Meeting, April 2,
1867. The Rev. John Gunn, M.A., F.G.S., President, in the chair.
A flint implement, picked up that day at Bramerton, by the Rev.
J. Gunn, was laid upon the table, and a communication read, stating
that another had been found at South Wootton.
The next subject was introduced by the Rev. 8. W. King, M.A.,
F.G.8., who said that the question as to the proportionate ratio
between the existing and extinct species of the Crag was now one
of considerable interest, and had been most admirably handled by Sir
Charles Lyell and the late Dr. Woodward. One of the most con-
spicious, as well as interesting, shells belonging to the Norwich
Crag was the Nucula Cobboldie. From a communication lately
received from Mr. Gwyn Jeffreys, he learned that Nucula Cob-
boldice had been found living in the Japanese seas, near Vancouver's
Island. He wrote to Mr. Jeffreys for full particulars, and received a
letter from him in which it was stated that the specimens dredged
near Vancouver's Island did not differ specifically from Nucula Cob-
boldig, and that Mr. Searles Wood confirmed this identification.
Now the fact of great interest was the finding of N. Cobboldie in
Japanese seas, so far removed from Hngland, and yet showing that
there must have been a marine connection between the two districts.
Leda myalis, too, which he had found under the Boulder-clay, but
above the true Crag at West Runcton, had been found living at the
mouth of the St. Lawrence. Mr. King showed a specimen of the N.
Cobboldice from Japan with others from the Norwich Crag. The Rev.
O. Fisher, M.A., F.G.S., remarked that they had been told by Mr.
Taylor that the Upper Crag was a deep-sea deposit; but it appeared
to him the Mya, Tellina, and Cardiwn were not deep-sea shells. The
Rev. 8. W. King said they were littoral shells. Mr. Fisher observed
that they were told the assemblage of species showed that the Crag
sea had been an area of subsidence, and that important alterations
in the fauna had taken place. He scarcely knew what species
there were in the bed, proving it to be more northern or arctic
Norwich Geological Society. dul
than the Norwich Crag, which rested immediately on the Chalk.
The Rev. 8. W. King said many living shells could now be found
upon the verge of low water-mark, but should the shore upon
which they rested be depressed slowly and gradually, the area on
which those shells were would be increased as they advanced to a
higher level. Mr. Bayfield was under the impression that Mr.
Taylor said the percentage of specimens found in the upper bed
would, perhaps, be a guide as to whether or not they were deposited
in a deep sea; for instance, Astarte borealis was found in the lower
bed, but in still ten times greater numbers in the upper. The Chairman
thought but little dependance was to be placed upon shells. If the
climate of the Upper Crag were truly represented by the many arctic
species found by Mr. Taylor, it was impossible that the Forest Bed
could have existed at that time.
Monthly Meeting, May 7.—The following paper was read by
Mr. J. H. Taylor, the Hon. Secretary :—‘“‘ The Upper and Lower Crags
in Norfolk.” Since I had the honour to read my last paper on this
subject before the society, I have from time to time followed it up,
and the results I now purpose to lay before this meeting.
That the two Crags—the Upper and Lower—are distinct in their
character, I have now no doubt. Mr. Searles V. Wood, jun., has,
since I read my last paper, recognised the Upper Crag as identical
with the Chillesford bed, not only from its organic remains, but also
from the strata which under- and overlie it. In this he is supported
by his father on conchological grounds. Mr. G. Maw also, with
whom I went over the ground, and who went straight from Norwich
to Chillesford to compare the two beds, has identified the Upper
Crag with the Chillesford bed. |
At the last meeting I was quoted as having stated that the Upper
Crag was a deep sea deposit. ‘This I never intended to assert. What
I first stated was, that the Upper bed bore evidence of deeper water
deposition than the Lower. I spoke in the comparative, not in the
positive, degree.
Taking the mean of the shells belonging to the Lower Crag, I
find that those which are rarest belong to the deepest zones. Thus
Pecten tigrinus may now be dredged from between thirty and forty
fathoms off the coast of Norway. It is exceedingly rare in the
Norwich Crag. .
oa
as
Mougton Lane.
Ta ST
Crummack Beck.
Crummack. Z
a4 oe Trinucleus zone.
L eee eee ~Strophomena zone
b [Saar Orthis zone.
(
Austwick Beck Head. 4
Bo. A CF
: A 3 B
co.
Capple Bank Wood. S
- ¢c
Lay |
N
a
z q
302 Hughes— Geology of the Lake District.
from under the flags. The junction crosses the road about half a
mile east south-east of Newfield House, and may be followed in a
west north-west direction into the next valley, where the boundary
line may be traced round to Studrigg Scar; the grits coming up
from below the flags on the south, west, and north. South of Swarth
Moor the grits are repeated by a fault parallel to the Craven Faults,
but older than the Carboniferous rocks under which it passes.
Owing to this fault, which is a broken anticlinal with a downthrow
on the north, the base of the grits (A.c. 2) is not seen until we get
to the Crummack Valley. They are thrown against a lower part of
themselves as far as Lower Bark House Barn, on the west of which
they come against (B.a.) the slates, grits, and ash-like beds above
the Coniston Limestone; then against the Coniston Limestone itself.
As this fault has a little more west in it than the strike of the beds
on the north: side, lower beds abut against it as we proceed west-
ward; and so the base of the grits comes against the fault near the
road between Austwick ‘and Wharfe, and can be traced from that
point, through Wharfe, across Crummack Beck, south of South-
thwaite Wood, across Crummack Lane, near the Limekilns, till it
disappears under the Scar of Mountain Limestone. As the grits
turn up again on the north, the base line may be traced across the
Beck, some way south of Crummack, and up to Moughton Scar;
but this line is much obscured by Drift. Under Moughton Scar the
slates (A.c. 3) are seen here and there, and lower down one small
boss of Coniston Limestone, just enough to prove that it comes there.
Some of the subordinate flags of (A.c. 2) may be seen north of Far
End Houses, where we have a bed about 60 feet thick. Some flagey
beds, probably at a lower horizon, occur in the grits north of White
Stone Wood, then curving round with the rest of the beds, may be
traced to about 100 yards west of Moughton Lane. A still lower
set occurs in Souththwaite Wood, and is, probably, about the horizon
of the flags of Hardland’s Plantation and Crag Hill Barn. In
several places along the east edge of the valley, under the limestone
cliff, flags occur, alternating with the grit.
The slates (A.c. 8) may be seen rolling about at small angles all
down the stream, from the base of the grits in Souththwaite Wood
to within 100 yards of Wharfe Mill Dam, where they are cut off by
the fault above mentioned.
About fifty yards west of the stream we come to the base of the
slates (A.c. 4) which is here a very coarse irregular conglomerate. This
may be traced for about a quarter of a mile west-north-west, frag-
ments of the broken ridge occurring along the fields south of South-
thwaite. A similar conglomerate is seen at Austwick Beck Head,
dipping north-north-east under some slates, and these again under
the grits and flags of Capple Bank, which I take to be A.c. 2.
At Austwick Beck Head the conglomerate rests on an irregular
cleaved mudstone, of which there is very little seen, and that much
weathered.
Below Souththwaite the conglomerate rests on a series of slates,
with subordinate more gritty bands (B.a. 2) which pass into rocks
Hughes— Geology of the Lake District. 308
very like what have sometimes been called ash-beds. Some of these
beds cross Crummach Lane just north of Norber Brow. One is
seen in the stream close to the Dam House Bridge. The series rolls
over, and several such beds are seen dipping to the south, near Jop
Ridding, Woodend, Staindale, etc. Below them the slates become
more flaggy (B.b. 3); have often long bands of concretions packed
parallel to the cleavage, so as to make it very difficult in small
‘sections to make out the bedding. They are well seen on Norber
Brow and under the Limestone cliff of Norber, in both of which
localities I found several specimens of Trinucleus. These beds pass
down into Coniston Limestone, which may be seen near Wharfe
Mill Dam, up Wharfe Gill Dyke, ete.
Thus it will be seen that the flags of Horton, in Ribblesdale, lie
in a synclinal, the axis of which slopes to the east-south-east; and so
in the Crummack valley, we have only the lower part of the flags
(A.c. 1) preserved in the hollow of the grits (A.c. 2), while, in
the Horton valley, we have the whole of the flags, and at its east
end even part of the grits above the flags (A.0. 4), preserved in their
then deeper trough.
Two anticlinals, also with their axes sloping to the east-south-
east, bring up the lower group (B) on the north and south of this
synclinal.
Along the northern anticlinal, the grit A.c. 2 (which is a more
marked bed than A.c. 3), is close upon the Coniston Limestone B.6. ;
along the southern anticlinal it is separated from the limestone by
a very considerable thickness of slates and shales, etc., with Lower
Silurian fossils.
Thus A appears to rest upon different beds of the underlying
group B.
Also the base of A is sometimes a conglomerate made up of frag-
ments of the older series B.
That is to say A rests unconformably upon B.
Such are the stratigraphical relations of the rocks in the district
under notice. From these data I have constructed a Vertical Section
(IV.), to which I shall refer by index letters and numbers, in offer-
ing a few remarks upon the lithological character and paleontology.
I have avoided giving names to the subdivisions, as I feel that
names derived from locality can probably be more conveniently
found in the typical region to the north and west, and that names
from characteristic fossils are not likely to hold good over large
areas, as all A, with which I have chiefly to do, is so undoubtedly
one group, that where similar conditions of sea bottom recurred, we
must expect to find that the same creatures were there or there-
abouts, ready to migrate and re-migrate to suitable areas. Probably,
also, most of the divisions will fit in with local names, already used
by Professor Sedgwick, such as Ireleth Slates, Brathay Flags, ete.
When the fossils, collected by Mr. Gibbs and myself, have been
arranged and determined by Mr. Etheridge, I hope to offer larger
and more trustworthy lists.
_ B.c. Green Slates.—These are the green slates and porphyry of
VOL, IV.—NO, XXXVI, 23
304 Hughes— Geology of the Lake District.
Professor Sedgwick. I have dropped the word porphyry, as I have
not in this district found any part of them which could be so called.
The specimen which I saw in the Kendal Museum also, from further
north, seems only a grit, though certainly altered a little. J have
not been able to detect any fossils in these beds, unless some obscure
black marks which J found in the slates due west of Twisleton
Manor House, should turn out to be traces of Fucoids or Graptolites.
Professor Harkness has, however, shown that their equivalents fur-
ther north are of Caradoc age, and the passage from the Coniston
limestone into them near Ingleton would seem to bear out this view.
B.b. Coniston Limestone.—A dark blue, close grained, more or less
calcareous slate and shale, passing into a hard blue grey crystalline
limestone. I have nowhere got the top and bottom of this bed in
one section, so I can offer no estimate of its thickness; nor am I
prepared to say that it is the very same bed that occurs at the
different places from which I have collected fossils, and not rather
limestone bands on slightly different horizons of the same series.
Fossils are abundant. Speaking generally, the same species occur
everywhere, though in some localities they are more numerously
represented than in others. Besides the localities referred to in the
description of the cross sections, this formation is well exposed and
highly fossiliferous in the upper part of Helm Gill, and above Gaw-
thorp near Dent; also in Sarly Beck, north-east of Sedbergh.
The following are some of the fossils :—
Halysites catenularia. Leptena quinquecostata.
Heliolites. LL. sericea.
Petraia equisulcata. L. transversalis.
Favosites fibrosa. I. small sp.
F. 2 other sp. Lingula, 2 sp. ?
Encrinites. Orthis Actonia.
Cystideans. O. biforata.
A Phyllopod crustacean. O. calligramma.
Calymene Blumenbachit (var brevi- O. elegantula.
capitata). ; 0. flabellulum.
Chetrurus bimucronatus. O. porcata.
Cybele verrucosa. O. vespertilio.
Lilenus. O. sp.
Lichas. Strophomena depressa.
Phacops conophthalmus. Murchisonia 2
P. sp. Lituiies 2
Remopleurides. Orthoceras.
Atrypa marginals.
B.a. Strongly cleaved slates. Near Souththwaite the difference
between them and the slates (A.c. 3), above may be well examined—
the latter being less altered, and showing the direction of the bed-
ding better. In the upper part the altered grits like Ash-beds
(B.a. 2) occur, below which, but some way above the limestone, the
Flagey Slates (B.a. 3) with packed concretions occur. In the upper
part of B.a. 3 fragments of Trinucleus become tolerably abundant.
So also in coming down Helm Gill we have a geologically ascending
section, and in the beds near the bottom, and therefore highest in
the series, we find Trinucleus, while fossils are scarce through the
beds immediately below. Also in coming south-west from Sarly
Hughes— Geology of the Lake District. B00
Beck we have an ascending series, and just above the limestone find
shales in which Strophomena alternata is the characteristic fossil ; and
much higher up, on the south-west side of Rawthay Bridge, shales
in which Trinucleus is abundant.
Limestones always form a convenient dividing band, both from
their pointing to some physical change, and from their marked
lithological character. Therefore, although B.a. passes down into
B.b., we may take an arbitrary line for the base of B.a., and we
shall find that a change has set in somewhere thereabouts.
In B.a. I have found—
Petraia subduplicata, var. crenulata. 0. calligramma—large close ribbed var.
Enerinites. O. sp.
Phacops apiculatus ? : : Strophomena depressa. ) Abundant in
is Chiefly in 2 P
Phacops, sp. (cbtusi- ye S. alternata. - the
caudatus ?) = : Lae S. sp. lower part.
Trinucleus concentricus, ) “PP&Y Part Orthoceras, ete., etc.
Orthis biforata.
A.c. 4. This bed is seldom exposed. Probaby it does not every-
where exist as a conglomerate, and, moreover, in the other parts
of this district which I have had an opportunity of examining, I
have never found the upper group near the lower, except where
I have plenty of independent evidence of its being brought on by a
fault. It is, however, well seen in a few places in the Crummack
Valley, where it is a very coarse irregular conglomerate, made up of
rolled and angular fragments, which appear to be derived from the
grits and fine conglomerates of the green slates; from the Coniston
Limestone series—some pieces are very like a bed seen in Bua.
close by ;—hbits of quartz and slates of various texture, etc. The
greatest thickness I could measure was about ten feet. The only
fossils I found were Favosites alveolaris? F. fibrosa. It may be
that the breccia-like limestone above the Coniston Limestone at
Crag Hill is the equivalent of this conglomerate. I have nowhere
seen a limestone of that character in the Coniston Limestone, where
it has been covered by beds undoubtedly belonging to the lower
group B.; also, the only fossils I found in it were the same corals
I found in the conglomerate ; but this is a point to be worked out.
A.c. 3. Slates very uniform in character throughout. Generally
a soft mudstone splitting by cleavage and joints into small rhom-
boidal pieces. Faint lines often indicate the bedding. I have not
as yet found any fossils in these beds. The thickness is probably
several hundred feet. They pass up through a roughly cleaved
sandy slate into—
A.c. 2. Tough grits, or greywacké,' with subordinate beds of
flags. These have as yet yielded no fossils. They are about one
thousand feet thick, and always, in this district, succeed the slates
(A.c. 3) with a very uniform character and thickness.
A.c. 1, Flags with subordinate thin beds of grit. These are the
1 The word ‘‘ greywacké” as defined by Mr. Forbes (p. 229, sup. foot-note) would
be a very useful term in this country. We want a name for the tough Silurian rocks
which seem to be something between a grit, or sandstone and quartzite——NSee Geol.
Mag., Vol. ILI. p, 206, foot-note.
356 Hughes— Geology of the Lake District.
Coniston Flags proper, in which are the great quarries. Where the
bedding and cleavage nearly coincide they form good flags, where
the cleavage makes a considerable angle with the bedding they split
along the cleavage; but the lines of bedding are well marked
across, and the stone breaks into irregular slabs of hardly any value
except as “troughs” for walling.
The thickness of these beds is about two thousand feet. Fossils,
with the exception of Orthoceratites and Graptolites, are very scarce.
I, however found the following ; quite enough to connect them with.
the beds above, instead of with those below :—
Favosites fibrosa, Littuites giganteus.
Actinocrinus pulcher.
Graptolites Ludensis.
G. sp.
Orthoceras primevum.
O. subundulatum.
0. sp. (ventricosum ?)
Pterinea tenuistriata 2 Worm tracks, etc.
Cardiola interrupta.
A.b. 4. Tough grit or greywacké, with a few subordinate flaggy,
or slaty beds. These are the highest beds seen in the Horton
district. I have estimated their thickness at about twelve hundred
feet on Casterton Fell. I have found no fossils in them there, or in
the Horton district; but fossils rarely occur in rock of that character.
Near Cautley Spout, north-east of Sedbergh, I found a large Lituites
in a tough grit, which I must refer to the top of this, or the bottom
of the overlying set (A.b. 3). Also, at Helmside, near Dent, there
are some flagey beds, near the top of what I take to be this grit
which have yielded the following :—
Cliona. Pterinea tenuistriata.
_ Spirorbis Lewisii. Cardiola interrupta..
Ceratiocaris Murchisoni (See Grou. Orthoceras Ludense.
Mae. Vol. III. p. 203). 0. bullatum.
C. robustus. 0. angulatum.
Graptolites Ludensis. O. 3 other sp.
G. sp.
A.b. 3. These are the sandy slates of Casterton, Middleton, and
Howgill Fells—more than 8000 feet thick. Having already
described them in the first mentioned locality, I will now only give
a list of fossils, to show that as a group they are the same as those
which occur down to the bottom of the Flags.
Petraia. Graptolites.
Encrinites. Pierinea tenuistriata.
Ceratiocaris Murchisoni. Cardiola interrupta.
C. robustus: Lituites.
Acidaspis. 0. sp. Salter. Orthoceras, 2 sp.
Phacops, sp.
Thus it appears that all (A.) is one series, characterized by such
fossils as Cardiola interrupta, that it rests unconformably on a lower
series (B.), characterized by such fossils as Orthis Actone and
Trinucleus.
1 gather from Prof. Sedgwick, whose kind help on all occasions I
take this opportunity of acknowledging, that A.c. 1 to A.c. 4, are
what he included under “Coniston Flags,” and I would therefore
merely wish to return to the classification which he published in
1846, and make the flags so defined the base of the Upper Silurian
Series.
Dr, T. Sterry Hunt's Lecture. O07
REPORTS AND PROCHEDINGS.
—__~<>—_
THE CHEMISTRY OF THE PRIMEVAL EARTH.
A Lecrure sy Dr. T. Srerry Hunt, F.R.S., F.G.8., DELIVERED AT THE Roya
Institution, Lonpon, on Fripay Eventine, May 31st, 1867.1
_ Mr. Prestpenr, Lapizs, anpD GENTLEMEN,—The subject of my
lecture this evening, as has been announced, is the Chemistry of the.
Primeval Earth. The natural history of the earth, 10 which we
give the name of “Geology,” 1s necessarily a very complex science,
including, as it does, the concrete sciences of Mineralogy, of Botany,
and of Zoology, and the abstract sciences of Chemistry and of
physics, not to speak of others. These sciences, and especially
chemistry and physics, have a very important relation with regard
to the whole process of development of our earth, and have, from
the very first time, exercised a most important relation with regard
to all its changes. And we have lately learned, from more extensive
study, that these chemical laws apply not only to terrestrial, but to
extra-terrestrial matter. Recent investigations show us in fact, as
might have been presumed, that all the other bodies of our solar
system, and bodies even of other systems, revolving around other
suns, have essentially the same chemical composition as our own
planet. The spectroscope, that marvellous instrument in the hands
of modern investigators, has thrown a light upon the composition of
the farthest bodies of the universe, and has made clear many points
which the telescope had not been able clearly to decipher. It has
shown us, as it were, matter in all its different stages, and has en-
abled us to trace the great processes of the condensation and the
formation, so to speak, of worlds. It is, as you are aware, long
since Herschel speculated upon the nebulous matter which seemed
to be diffused in different parts of space. Some of these nebulz Lord
Rosse and others were able, with their great telescopes, to resolve, and
to show that they were really composed of stars; and thence there
came a doubt whether there were really such masses of nebulous
matter diffused as had been hitherto maintained, but the spectroscope
has placed that beyond a doubt, and has enabled us to see in the
bodies in the heavens above, not only planets like our own earth
shining by reflected light, and other bodies like the sun, consisting of
luminous and apparently solid particles, but also others still—true
nebulous masses, that is to say, luminous gaseous matter,—these
three forms representing, as we may suppose, three distinct phases
of the consolidation or the condensation of the first primal matter
from which our earth, as well as all the other bodies of the solar
system, would seem to have originated.
This nebulous matter we conclude to be intensely heated—so in-
tensely heated as to be completely gaseous, and, in fact, to owe this
gaseous form to its intensely elevated temperature ; being, however,
comparatively feebly luminous when we contrast it with the solid
1 Being a full report taken down verbatim in shorthand, and now printed for the
first time.
308 Dr. T. Sterry Hunt’s Lecture—
matter which appears in the flames of burning gas and in most other
terrestrial flames, or compared even with the light which has
emanated from the sun itself.
But still further, the spectroscope has enabled us to discern in the
matter of the sun, and, to a certain extent, in the matter of the fixed
stars—which, as you are well aware, are other suns, the centres of
other systems—for the most part the same elements with those which
make up our own earth. .
You have probably already had explained to you in this place—
and it would be foreign to my object to-night to speak of it—the
mode in which these investigations have been conducted ; but of the
great conclusion you are aware, that the commonest, elements, the
sodium, the iron, the magnesium, and most of the other commonest
elements of the crust of the earth also enter into the composition of
the sun, and enter into the composition, moreover, of the fixed
stars—that is to say, of other suns. And here it is singular how
modern science has realized the gentle intuition of the poet. Long
since we heard a poet singing, who told us that he
‘“« Saw alike in stars and flowers a part
Of the self-same universal being
That is throbbing in his mind and heart ; ”’
and this, which seemed little more than a poet’s fancy, has been
realized in the most prosaic way by modern investigation, which
shows us from the examination of the light of the sun and of the
stars, the very elements which enter into the composition of our own
earth—which actually enter into the composition of our own bodies.
Still farther, we know the sun is intensely heated. Calculations
have been made as to the amount of heat and of light which have
radiated from the sun, and of the temperature of the surface of the
sun. ‘The figures which are required to represent that heat are so
immense that it is really difficult for the mind to conceive of the
intense elevation of temperature which exists in that body. And
modern chemical investigation has thrown a curious light, it seems
to me, upon the nature of the action which is going on at the sun’s
surface, and upon the source of the luminosity of that body. We all
know that heat is favourable to chemical combination,—that, under
ordinary conditions in the laboratory, if we wish to effect a com-
bination of two bodies, we expose them to heat; but it has been
found that a higher degree of heat reverses all these affinities, or
most of them. Many of the metals—the “noble metals,” as we
call them, like gold and silver—are capable of forming combinations
with oxygen, for instance, but at a higher temperature the oxygen
goes off and the metal is regenerated. A similar thing was shown
many years ago by Mr. Grove, with regard to water. The elements
of water, oxygen and hydrogen, brought together at the elevated
temperature of the electric spark, unite to form water; but at a still
higher temperature the compound is again broken up into its two
elements, so that if you have these elements at a very high tem-
perature, cold would actually produce the effect of combination. A
certain point, either of heat or cold, would really produce a similar
,
The Chemistry of the Primeval Earth. 359
result—the combination of these elements ; and thus, literally, to use
Milton’s line, “frost would be found to perform the effect of fire.”
Now, it seems from still later investigations by Deville and by others,
that this great law of indifference of bodies when intensely heated
is a universal law, and that this principle, which Deville calls
‘‘ dissociation,” probably extends to all matter. All the substances
that we know would probably, at a sufficiently high temperature, be
dissociated: that is to say, the various elements which make up the
earth—which make up any body—when in this state of intense
ignition would be uncombined, and, moreover, would all be capable
of being reduced to the state of vapor—to the state of gas; and this
we must conceive to be the real condition of the matter which
forms the sun.
Now what must be the process going on at the surface of such an
immense mass of matter, intensely heated, but by the very fact that
it is gaseous, but feebly luminous? You are well aware that a
hydrogen flame without any solid matter in it, though giving a very
high temperature, emits almost no light whatever. At the surface
of this enormous globe, the sun, a process of cooling would be going
on; and there such bodies as at the still very high temperature
were capable of uniting—to form oxides, let us say——would be pre-
cipitated, and would form a sort of mass or cloud suspended in the
still dissociated vapours, and would then give off light and become
intensely luminous, as such solid particles necessarily are, and would
thus give rise to a brilliant light, and would also radiate the sun’s
heat. Hence we suppose that at the surface of the sun, and at the
surface only, there is this process of condensation going on. This
hypothesis, lately put forward, has, I am aware, been opposed; but
it does not seem to me that the arguments which have been brought
against it are valid, and I cannot but think, from the present state
of our knowledge, that it affords us something like a correct idea of
the nature of the action which is going on at the sun’s surface.
But you will ask what all this has to do with our earth? Very
much, and for this reason: the almost universally accepted hypo-
thesis with regard to the origin of our solar system, not to speak of
other systems, is that the different bodies of our system—the sun
and the planets which compose it—have been evolved out of a
common nebulous mass.
Now, whether we admit that nebulous. mass in rotating to have
thrown off successive bands, which bands have been broken up and
agglomerated into worlds, or whether, with Chacornac and some
others, we suppose that in the midst of this great nebulous mass a
process of concretion went on by which an enormous ball of
vaporous matter resolved itself somewhat as you may see, a white
cloudy mass, at times breaking up and resolving into smaller masses
of clouds,—I say, whether you adopt one or the other notion with
regard to the breaking up of this great nebulous mass, and the
formation from it of sun and of planets, you come to the conclusion
that our earth must at one time have been a portion of such a nebu-
lous mass as is the sun at the present day: in other words, it must
360 Dr. T, Sterry Hunt's Lecture —
at one time have been a gaseous mass; it must at one time have
been a mass so intensely heated, that this process of consolidation
was only going on at the surface. It was once a self-luminous body,
such as the sun is at the present day, but being very much smaller,
the process of cooling has gone on with a very much greater rapidity.
Now there comes up another question,—whether, in this process
of concretion, or agglomeration, or separation, which has gone on n
this nebulous mass, all the masses—all the subordinate masses—
have the same composition,—whether this great mass of vapor was
homogeneous or not. ‘That we cannot certainly decide, but from our
present knowledge it would seem extremely probable that it was so.
But let us consider this cooling to go on, and, as in the case of the
sun, a condensation taking place at the surface. This mist-like
matter, as it became solid or liquid, having a certain weight, would
fall down toward the centre of the sun, or of the planet which
was then like the sun, and undergo the process of heating again,
From the constant contraction going on in this mass, the process of
losing heat, and of gradual condensation, would be going on until
you arrived at the point of liquefaction, that is to say, at the point
where there were certain compounds which could exist without
decomposition even at the centre, in other words, until you had
cooled it below the decomposing, the dissociating point of certain
compounds. Let us suppose that certain of the metals are capable
of combining with oxygen and forming compounds so condensed and
so fixed that they resist the decomposing action; then, and then
only, would commence the formation of a liquid nucleus. That
once begun, a process of condensation would go on until in each one
of these planets—in our earth for example—you would have even-
tually a great liquid globe, an igneous fluid mass, surrounded by
intensely heated vapours.
Now as to the composition of this mass. Whether it would be
homogeneous or not becomes a question. I think it extremely
probable that in such a mixture as this you would have toward
the centre a progressive condensation and accumulation of matters
denser than at the surface. This idea has been a favourite one with
many who have speculated upon the density of the earth, for you
are well aware that the earth, weighed as a whole, has a specific
gravity of something over five,—five three-tenths, as was determined
by Maskelyne,—that being, in fact, about twice the density of the
superficial parts. Hence, I think it extremely probable that we
have at the centre metallic or metalloid masses of elements, grouped
in different proportions from any that we have at the surface, and in
that way we have explained the great density of the earth con-
sidered as a whole.
But next with regard to this central mass. Would it remain
fluid, or would it become solidified? And here I am aware of a
notion very widely entertained and very generally taught in our
text-books on geology, that the earth’s centre is a liquid mass, and
has only a crust of from fifteen to twenty or twenty-five miles in
thickness, a crystalline solid rock which bears us upon its surface.
The Chemistry of the Primeval Earth. 361
This notion is supported to a great extent by fallacious reasoning.
Tt is said that in the cooling of such a fused mass solidification
would naturally commence at the surface ; and people have reasoned
in that way from a fact which is common to the observation of all
of us—the freezing over of our lakes and vessels of water during
the winter season. We find that the ice forms at the surface of the
water, while the mass ‘below remains liquid; but modern investi-
gation has shown us that water is an exception, differing in this
respect from almost all other substances; and that while ice is
lighter than the water upon which it forms and upon which it
certainly floats, the solid congealed material of almost all metals,
and of all rocks, slags, and such fused substances as might be sup-
posed to form this condensed mass of the globe, is very much
heavier than the liquid. Without going into the details of these
experiments, which have been very carefully made and verified by
numerous investigators, we may say in a few words that the process
of cooling in a mass like this would be just like the cooling of a
great bath of metal or of sulphur; in other words, the condensation
or congelation would commence at the centre and extend outward
toward the surface, so that the temperature of the centre would
therefore be the temperature of congelation. Matters, too, con-
gealing at the surface and going down towards the centre, even if
they met a somewhat higher temperature below, would not be
exposed to melting, for the beautiful investigations of Messrs.
Hopkins and Fairbairn have shown that in such cases pressure
actually increases the act of fusion, so that the pressure at the
surface actually favours the solidification of the mass, and the
temperature at the centre would be actually the temperature of
congelation, which is said to increase with the pressure. It has
been assumed that this increase was indefinite, so that it was easy in
that way to imagine a heat of intense whiteness at a few miles only
from the surface ; but you will at once perceive that if these matters
had cooled to the solidifying point at the surface and then gone
down towards the bottom, it is only the congealing point at the
surface which will represent the maximum temperature of the
centre of the earth.
Now comes a very curious question: what is the composition of
this fused mass,—or, rather, what is the composition of the largest
stratum which remains at the surface ?—for, as I might show you,
did time permit, there is no reason to believe that any portion of this
great fused mass, with the exception of the very surface, has ever
taken any part in the subsequent changes which have gone on in the
earth’s crust. In other words, we must find in the first few metals
of that solid crust, and in the gases and vapors that surround it, the
source of all the materials which now make up the solid stratified crust
of the earth, the waters of the ocean, and the atmosphere.above us. Let
us imagine all these materials to be brought together and fused. Sup-
pose all the elements of the visible earth that we know to melt with
fervent heat, the chemist, by a knowledge gained in his laboratory,
will easily understand the nature of the reactions. All the carbon
362 _ Dr. T. Sterry Hunt's Lecture—
which is in the form of coal would be burned and converted into
carbonic acid. All the siliceous matters which make up the earth’s
crust, the quartz and the sandstones, would act upon the carbonates
of lime and expel all the carbonic acid. The waters of the sea,
volatilized, would leave a residue of salt and of gypsum behind
them ; and these materials again acted upon by the excess of sili-
ceous matters in the crust, in the presence of water, would expel
all the chlorine in the form of hydrochloric acid. All the sulphur
_ would be diffused in the atmosphere in the form of sulphurous acid ;
and eventually all the lime, the magnesia, the soda, the potash, and
the metallic bases would be combined with alumina and silica in a
great fluid magma whose composition would be, perhaps, more like
the slag of some of our iron furnaces in its composition than any-
thing else we know; and the slow cooling of them would probably
develop various crystallme compounds. ‘The cooling of such a mass
at length would render it somewhat viscid ; and then, as I mentioned,
inasmuch as the solid rock is always denser than the liquid, you would
have irregular shrinkings and corrugations of the surface, so that the
first cool surface of the globe would be a scoriaceous slaggy mass,
as I conceive,—with exceedingly irregular outlines of hill and valley,
—a curiously depressed and corrugated surface,—perhaps such a
surface as the moon presents to us through a telescope,—perhaps
such a surface as we observe on a mass of fused silver after it has
come out of the furnace and is giving off the gases which it has
absorbed,—and it is very probable that gases may be absorbed
during the cooling of this scoriaceous mass.
But then let us ask what is the composition of that atmosphere.
In that atmosphere we should have the whole of the carbon im the
form of carbonic acid; the whole of the chlorine in the form of
hydrochloric acid; the sulphur as sulphurous acid ; and we should,
moreover, have nitrogen and probably an excess of oxygen. This
great accumulation of gases, and of hydrogen in the form of watery
vapor, would give rise to an atmosphere of enormous density. The
atmospheric column at that time must probably have weighed upon
the earth’s surface with a weight seven times that of our atmosphere
at the present day, and the cooling of this crust would have then
gone on very, very slowly. Heat would radiate with extreme
difficulty from this mass, and ages would take place probably before
the cooling came on to such a point as to admit of condensation.
But just let us conceive that under this high column, this great
pressure, condensation of water would take place at a very much
higher temperature than it does under our present atmospheric
column. That water might remain in a liquid state on the earth’s
surface at temperatures, perhaps, of 300 or 400 degrees ;—this
would depend upon the unknown height of this great barometrical
column, of which we have not sufficient data to determine the exact
weight. Then this first water coming down, moistening the surface
of this crust, would be intensely impregnated with acids, especially
hydrochloric acid. We all know from chemical investigation that
this rocky slaggy mass would be readily attacked on the surface by
The Chemistry of the Primeval Earth. 363
these acids. Indeed, the action would probably be very energetic,
and would go on until the whole of the affinity of the acid
was saturated at the expense of the lime, magnesia, and soda, and
other metallic bases which form a portion of this crystalline scoria-
ceous mass—this primary slaggy surface. The silica separated at
this high temperature, if we may judge from the investigations of
chemists, would take the crystalline form, and you would thus have,
naturally, great deposits at the surface of the earth of silica, pro-
bably in the form of crystalline or granular quartz; and you would
thus have a separation of quartz on the one hand, and on the other
hand you would have the waters of the primeval ocean intensely
impregnated with chlorides and sulphates of all the bases which
were at first combined with this quartz—with this siliceous matter.
This process is a submarine one; that is to say, it would take place
only in the depressions of the earth’s surface where these waters
accumulated. And it would be a very rapid process. The action
would very soon be exhausted, because the affinities of these acids—
hydrochloric acid, and sulphurous acid, and perhaps sulphuric acid
—-formed at that temperature would soon be satisfied. Then comes
another and a slower process, which would be effected upon the
exposed portions of the crust by the carbonic acid in the atmosphere,
combined with the moisture there present,—a process of slow decay
and transformation of all these silicates which are thus exposed ;
and that is a process similar to that which is now going on at the
surface of the earth by which our hardest granites and gniesses,
hard felspathic and pyroxenic rocks, are broken down and converted
into clay—a process which even makes the granites of Comwall
crumble into Kaolin. In the elimination from these felspathic rocks
of the alkali which they contain—the lime, magnesia, and soda—
there would be a separation of silica and alumina in the form of
clay, which remains insoluble at the surface of the earth, and the
formation of carbonates of soda, of lime, and of magnesia, these
carbonates being formed at the expense of the carbonic acid in the
atmosphere, which is absorbed by these bases at the moment they
are liberated ;—and these, through the condensing waters or rains
which are falling upon the surfaces exposed to subaérial action, are
carried down into the sea, where their first act would be to pre-
cipitate aluminous matters,—to precipitate at that high temperature
all the denser metals, and, finally, to give us a sea which would
consist only of lime, magnesia and soda.
Now, that process is still going on—has been continued down to
our present time, and it is one which is constantly operative at the
surface of the planet,—slowly, very slowly, at the present day, it is
true, because the amount of carbonic acid in the atmosphere is now
very much less than it was at this former time.
Thus you see the result of this subaérial decomposition of these
rocks gives rise to clay; but the carbonate of soda going down into
the sea decomposes the lime-salts in the sea: and precipitates
carbonate of lime,—in other words, limestone. First, the action
gives rise to solid quartz-silica; secondly, to the formation of clay ;
364 Dr. T. Sterry Hunt's Lecture—
and thirdly, to the formation of carbonate of lime or limestone; and
in these three elements you have, as it were, the alphabet of all our
stratified or water-formed sedimentary rocks. Sand (broken up
quartz), clay, and lime, in various proportions, either in their simple
mechanical mixture or, secondly, combined by chemical action, make
up the whole of the rocks with which we have to deal,—of course
including iron and some other metals which intervene, to a very
secondary degree however.
Thus I have endeavoured, so far, to show you how these processes
naturally going on, give rise to the elements which make up these
stratified and sedimentary rocks. It belongs to physical geology to
explain the breaking down of these sediments and their mechanical
distribution, and the subsequent origin of the different varieties of
rocks; and we can only indicate the general chemical law which
has thus presided.
But here you see not only the origin of these three great classes
of minerals which make up the rocks, but you see the origin of the
saltness of the sea. That is a question which has very much
puzzled and perplexed many who have written upon the subject,—
whence the sea derived its salt. It has been said by some writers
that the source of the salt was to be found in the land, because salt
was recognized as an element in the rocks; and some even went so
far as to contend that the origin of this salt was to be found in
igneous action. They imagined in the centre of the earth a source
from which all its materials were extruded, and rock-salt among
them ; but a very careful series of investigations upon the composi-
tion of ancient waters, the mineral waters, which are nothing less
than the fossil sea-waters locked up in the ancient rocks, have
shown that there has been a slow progressive change in the consti-
tution of the ocean, and that by means of the action of carbonate of
soda, derived from the decay of the solid rocks, there have been
separated the whole of the carbonates of lime, which make up the
calcareous strata—the marbles and the various limestones which we
find on the earth’s surface. It is not unusual to say that these
limestones are the result of organic action, because we find them to
a great extent made up of shells, of corals, and of the remains of
calcareous animals. That is very true, but these animals can only
appropriate the carbonate of lime which they find ready formed at
their hands; and that carbonate of lime has been formed from the
salts of the sea by reason of this peculiar decomposition which I
have just now explained.
But this takes us a step farther; for if the rocks are decomposed
by virtue of the carbonic acid of the air, there has been a great
separation of carbonic acid from the atmosphere. You will recollect
that we supposed that at first the whole of the carbon which has
since gone into the solid crust of the earth was diffused in our
atmosphere, thus giving a composition very different from that
which we have at the present time. Now, we all know that this
carbonic acid in large proportion is unfavourable to the development
of the higher forms of life; and we see, therefore, in this slow
The Chemistry of the Primeval Earth. 369
chemical process by which the carbonic acid has been separated
from the air, the agency which has progressively purified our
atmosphere, and has fitted it for the support of the higher forms of
animal life, so that every clod of clay represents a very instructive
series of processes. That clod of clay tells us of the decomposition
of an old felspathic or granitic rock as it were—of the separation
from it of carbonate of soda,—of the decomposition of the salts of
lime in the sea water,—of the formation, therefore, of an equivalent
of carbonate of lime,—of the formation of common salt,—and of the
separation from the atmosphere of an equivalent of carbonic acid ;
and thus the great law of equilibrium binds together the composi-
tion of the solid crust of the earth, of the waters, and of the air.
We have thus considered two great sets of action. Principally,
however, I should say we have considered the action from without—
the action of acids and gases and vapors upon the solid crust of the
earth. But you will ask, is there no action from within? Geolo-
gists have been prone to assign the action of the central fire as the
source of almost all the changes which take place at the surface of
the earth ; and shall we exclude that from our scheme? No, cer-
tainly not; but I dare say that when I spoke of this solid crust of
the earth, the question was asked by many in their own minds
whether that first-formed crust was not identical with granite. It
is a very common notion that granite forms the substratum of the
earth—that it was the rock upon which all other rocks were built.
Now, in the first place, I would remark that we have not evidence:
anywhere of an exposed portion of that crust of the earth. In fact,
by the very conditions of the problem, as I have put. them forward,
we would conceive a complete decomposition, acomplete destruction,
of all that crust either by submarine or subaérial agency,—the break-
ing of it down into clay or into other elements of that kind, so that
everywhere the primitive crust of the earth is buried beneath its own
ruins. But if we may be permitted to imagine the composition of
that primitive crust—to reconstruct it, so to speak, as I have just
now done—you will see that its composition would have excluded
altogether free silica,—would have excluded quartz, and that this
very quartz, which is one of the constituent elements of granite, is
only the result of a secondary chemical process which I have just
explained to you; so that, in fact, the granites and the gniesses and
all these rocks which at the earth’s surface now appear in a disruptive
extruded form are, in fact, older rocks decomposed by water—the
results of the metamorphism of the older rocks themselves deposited
from water.
One point (and I beg pardon for having omitted it just now) with
regard to the composition of this earlier atmosphere. Unfitted as
it was for the higher forms of life, still from the comparatively large
amount of carbonic acid present, it would seem to have been pecu-
liarly fitted for the development of luxuriant vegetation ; and it was
long since pointed out by Brongniart that we might suppose a mar-
vellous luxuriance of vegetation in earlier periods of the earth which
gave rise to enormous beds of coal and other fossil fuel; for we
366 Dr. T. Sterry Hunt’s Lecture—
should judge that this abundance of carbonic acid favoured a wonder-
ful development of vegetation, and, at the same time, the elimina-
tion of the carbon in the shape of coal, helped powerfully to purify
the air at that time.
But there is another little question which comes up with regard to
the vegetation of these early times. We find, not only under the
tropics, but over the whole of the British Islands, and even within
the Arctic circle, a wonderful vegetation. Ferns and palms, such
as are now found growing only within the tropics, once grew within
the Arctic circle, and, indeed, very near the Poles. A very curious
and beautiful explanation of that has recently been presented by
the experiments of Dr. Tyndall, which I believe have been first
made public in this very Royal Institution. He observes with
regard to carbonic acid, and many other gases of that kind, that
their relations to radiant heat, and notably to obscure heat, were
such that a very small proportion—a few hundredths—of that car-
bonic acid diffused through the atmosphere would be quite sufficient
to prevent, almost entirely, the radiation of obscure heat from the
earth’s surface; so that an atmosphere constituted, as I have shown,
from chemical grounds, the atmosphere of these early times must
have been constituted. would permit the solar heat to pass through
our atmosphere, but would prevent its escape by radiation after it
had once heated the surface of the earth, and would thus immensely
augment the temperature of the lower strata of the atmosphere,
producing an effect precisely as if we had covered the whole earth
with an immense dome of glass,—had transformed it into a great
-Orchid-house,—and had thus established, from the equator to the
poles, a moist, warm, equable climate, which would permit, even
within the limits of the polar circle, a luxuriant vegetation.
This wonderful explanation of one of the most obscure problems
of geology, comes from the investigation of the relation of different
gases to radiant heat.
I might go on still farther—(the subject tempts me)—and speak
of another curious class of phenomena that went on at the earth’s
surface in these earlier times, and with regard to which the atmo-
sphere of that period played a very conspicuous part—the formation
of Magnesian limestone, or Dolomite. You all know how over great
parts of England the Mesozoic rocks are made up in great pro-
portions of carbonate of lime combined with magnesia. Wherever
you have gypsum beds you have a large quantity of this dolomite.
The formation of this substance has been a very obscure problem.
I have found, however, that by certain reactions in which carbonate
of lime intervened with the salts of the sea—reactions hitherto
unsuspected—it was possible to explain the formation not only of
gypsum, but of dolomite, but with one exception : I found that the
carbonic acid, which was an indispensible condition in the success of
that experiment, was constantly going off by diffusion. My ex-
periments were constantly interrupted by the spontaneous evolution
of the gas. I remembered, however, that we must admit that in the
earlier times we had an atmosphere with several hundredths of
The Chemistry of the Primeval Earth. 367
carbonic acid: the whole phenomena of limestone require it; and, in
fact, the whole chemical conditions for this hypothesis which I am
explaining to you require it. Let us see what will be the effect of
preparing an artificial atmosphere. If we endeavour to reconstitute
such an atmosphere as must have involved this globe at the time
these rocks were being deposited, let us see whether we cannot get
the conditions for the formation of these rocks. In an apparatus
fitted for the purpose I surrounded the required materials with such
an atmosphere as existed in the coal-period, and I found that under
that artificial atmosphere, providing the conditions for evaporation,
the whole series of phenomena went on perfectly, and there was no
difficulty in producing carbonate of magnesia and gypsum; and, in
fact, I had here another confirmation of the notion of the highly
carbonated condition of the atmosphere in paleeozoic and mesozoic
times. That theory is confirmed by climate, by vegetation, and by
the singular series of reactions which have hitherto been a perplexity
to chemical geologists.
But we have hitherto been considering, as I said before, only super-
ficial actions—actions in which gases and vapors and matters diffused
in the atmosphere are operating to produce the slow decay, crumbling
down, denudation, and disintegration of the solid crust so that the first
inequalities of the earth’s surface would be rapidly effaced ; and the re-
sult of all this would be, to reduce the whole surface of the earth to a
dead level were it not that there is below a counteracting force, and
that that counteracting force is no other than the central heat, that
central heat operating directly upon these buried sediments, giving to
the lower strata a softness and plasticity so that they give way under
the superincumbent pressure of accumulated masses of sand, and of
clay and of gravel. These slowly send the other matters down until
they came within the sphere of the central heat, and thus they in-
directly produce those effects which have been by most writers attri-
buted to direct outbursts of the central fire. The generally received
opinion is, as you are aware, that volcanoes and igneous eruptions
have their seat in this great fluid bath, upon which floats the thin
crust upon which we live; but in the great density of these solidify-
ing cooling rocks I have already demonstrated a chemical reason for
repudiating that doctrine.
It would be foreign to my object to-night to enter into a dis-
cussion of the physical, mathematical, and astronomical reasons,
which have been given against that doctrine, and which go power-
fully to support this practical reasoning. I may appeal, however,
to the labours of the late Mr. Hopkins, of Cambridge, who, by his
admirable combination of mathematical and geological science, con-
tributed so much to the advancement of geology. He was able, by
very careful calculation upon the precession of the equinoxes and
upon the phenomena of mutation, to conclude that the earth, if not
solid to the core, must be almost solid; and Professor Thompson,
from the theory of the tides, and Archdeacon Pratt, of Calcutta, have
also arrived at conclusions which support completely those arrived
at from purely chemical data, namely, the essential solidity of tho
368 Dr. T. Sterry Hunts Lecture—
great mass of the earth, and, consequently, of the independence of
volcanic phenomena of any supposed theory of a fluid nucleus
within. Yet itis not the less true that we have in volcanic phe-
nomena a condition of things which recals sufficiently the state
which must have existed at the very commencement of solidification
upon our planet ;—that we have still evolved molten rocks, which
are very like what I suppose this first scoriaceous crust of the earth
must have been ;—that we have evolved from these volcanoes dif-
ferent gases and vapours such as must have floated over the surface of
the first formed and first solidified planet; and they come in as
beautiful explanations of what I was endeavouring to explain— the
composition of this crust, for they are really the result of the melting
together of the successive interstratified and intermingled layers of the
earth’s crust, and may represent,over very considerable areas, the mean
composition of the stratified rocks. When these become depressed,
so that they come within the action of the central heat passing up-
ward by radiation, then takes place the fusion, the melting together
of the limestones, of the clay, of the salt, of the gypsum, and of the
. gault together with the sand, and there are produced these fused
scoriaceous masses which we call lavas; and, at the same time, are
liberated enormous masses of elastic fluids and gases which produce
all the phenomena of volcanic eruption. However, in certain cases
where there is no disengagement of gases you have simply the
crystallization of the rocks—the conversion of them into what we
call granites, or gneisses, or mica-slates, and other varieties of crystal-
line rocks which form so often our great mountain chains. And we
have, morever, in the movements dependent upon this crystalliza-
tion, depression in one part and upheaval in another. We have
those movements which preserve the irregularity of the surface of
the earth, which prevent it from being entirely depressed beneath
the level of the sea and converted into one vast ocean. And here
we see coming up the old vexed question of the Neptunists and the
Plutonists. There are persons still living who recollect the con-
troversy which raged at the close of the last and the beginning
of the present century, and which in Germany and Edinburgh
raged with such virulence that the opposing parties were almost
broken up socially. You had the school of Werner or the Neptunists
on the one hand, and the school of Hutton or the Plutonists on the
other. The one endeavoured to create the earth entirely by water,
and the other as entirely by fire. In the light of modern chemistry,
I think we may now sately conclude, that the origin of the earth was
first an igneous mass,—that fire came in and did its work until a
cooling took place sufficient to allow of the precipitation of water,
and from that time the mechanical action of water, and the chemi-
cal action of water, and of acids and gases, were the principal means
in modifying the rocks at the surface of the earth, and it was only
when these became thickly accumulated, and depressed below a cer-
tain level, that they came again within the domain of Pluto, where
the igneous actions were again commenced, which produced those
igneous rocks which were confidently appealed to by the Plutonists
Geological Society of London. 369
as the proof of their hypothesis. Thus you see both hypotheses
justified by the latest investigations in chemistry and geology.
In this sketch which I have endeavoured to present to you of the
way in which chemical forces have operated upon the surface of our
planet, I may seem, to some of you who are familiar with chemical
processes, to have drawn somewhat upon my imagination; and yet I
conceive that there is not a principle here adduced which is not sup-
* ported by the most rigorous chemical investigation. If we once ad-
mit this nebular hypothesis, which I think we can scarcely fail to
admit in the light which telescopic and spectroscopic investigations
have now thrown upon the sun and the other bodies of the great
universe around us,—if we admit that,—if we admit the laws I have
-explained of association by cooling, and the ordinary play of chemical
affinities that must come in, in the case of cooling bodies, we can
scarcely doubt that the reactions that come into play have been
essentially such as I have explained to have taken place in the essen-
tial order in which I have enumerated them.
I should have been very glad, if the time permitted—but it does
not—to enter still farther into the discussion of many secondary
points which arise here,—the whole theory of metalliferous deposits,
of metallic veins, of mineral springs, of thermal waters, and of
gaseous emanations from the earth,—and to show that all of these
flow as natural, and necessary, and logical consequences of the
scheme of chemical geology which I have put forward briefly to-
night. I hope, however, that in these few remarks I shall have
made these principal points so plain that you may see that chemistry
has already been able to do something to elucidate the history of our
planet, and that a chemical consideration of this kind is not altogether
out of place in the hall of the Royal Institution, which the labours
of such eminent men as a Davy, a Faraday, and a Frankland have
made, as it were, a classic temple and a fane of science.
GxoLoeicaL Socrety or Lonpon.—June 5, 1867.— Warington
W. Smyth, Esq., M.A., F.R.S., President, in the chair. The following
communications were read :—.
1. “The Alps and the Himalayas: a Geological Comparison.”
By Henry B. Medlicott, Esq., A.B., F.G.S.
Current opinions on Alpine geology were first fully discussed by
the author, especially as regards the abnormal nature of the actual
boundary of the Molasse with the rocks of the higher Alps, including
the explanation usually given of this phenomenon, and of the con-
tortion of the inner zone of Molasse, namely the direct upheaval of
the main mountain-mass. Mr. Medlicott then described some of
the sections exposed on the south flank of the Himalayas, and sug-
gested a parallelism between them and those exhibited in the Alps.
The clays, sands, and conglomerates of the Sivaliks are very like
those of the Molasse; and in both regions the coarser deposits pre-
vail towards the top. In the Himalayas also the younger Tertiary
deposits almost invariably dip towards the mountain range which
they fringe, the plane of contact inclining in the same direction,
VOL, 1V.—NO, XXXYIILIL. 24
370 Geological Society of London.
and thus producing actual, though not parallel, superposition of the
older rocks. All the arguments which have been used to prove
prodigious faulting in the case of the Alps would therefore, the
author stated, be quite as applicable to that of the Himalayas. But,
as regards the latter range, Mr. Medlicott brought forward evidence
which appeared to him sufficient to prove that the present contact
of the Sivalik formation with those mountains is the original one,
modified only by pressure, without relative vertical displacement ;
and that the sinking of the mountain-mass is the proximate cause
of the contortions of the Tertiary strata. He then endeavoured to
show that this explanation is equally applicable to the Alps, espe-
cially as it seems also to account for collateral phenomena which
appear difficult of explanation consistently with the ordinary hypo-
thesis ; and he concluded by discussing the current theories of the
formation of lake-basins, in relation to the more immediate subject
of his paper.
2. “On some striking instances of the Terminal Curvature of
Slaty Lamine in West Somerset.” By D. Mackintosh, Esq., F.G.S.
Whilst engaged in investigating the nature and extent of oceanic
and atmospheric denudation, and the origin of superficial accumula-
tions in the West of England, the author observed, on the nearly
level floor of one of the valleys which indent the Quantock Hills, the
lamin of Devonian (Carboniferous ?) Slate, very regularly and
distinctly bent backwards towards the south.
Sections near Wiveliscombe exhibited some interesting instances
of the curvature of the laminzx, the line of demarcation between the
commencement of the curving back and the undisturbed mass of
slate below, being remarkably distinct and straight when looking
along the strike of the cleavage; but upon looking at right angles
to the strike, the surface formed by the edges of the laminz beneath,
though as distinctly marked, is very uneven.
At Raleigh’s Cross other instances of the curvature are seen.
The most important fact in connection with the sections was thus
stated,—the bending and curving back over extensive areas has
taken place on perfectly level ground with a declivity instead of an
elevation on the side whence the movement must have come.
An exaggerated continuation of the general curving back is seen
at Gupworthy, which at first sight appeared to be part of a denuded
anticlinal fold. Instances, much less decided, have also been ex-
posed in a cutting of the Exeter and South Devon Railway near
Plymouth, and near Torquay.
In all parts of Devon, West Somerset, and Cornwall, if not in all
districts were the slates are flexible, and where the cleavage laminz
dip at a considerable angle to the south, or where they are vertical,
with an approximately east and west strike, similar appearances
might be discovered, irrespective of the outline and inclination of
the ground.
In the author’s opinion the curving back of the slaty laminze in
this district must have been produced by a great weight of solid
matter propelled in a southerly direction.
Gunn—Glacial Deposits on the East Coast. 371
Norwica GxroLocicaL Svcrety.—THEe ORDER oF SUCCESSION oF
THE PRE-GLACIAL, GLACIAL, AND Post-GLACTAL STRATA IN THE Coast
Sections or NorroLk anD SuFFOLK, (with especial reference to a sec-
tion at Happisburgh, in Norfolk, and Corton, in Suffolk). By the Rev.
Joun Gunn, F.G.S.—Mr. George Maw, in an article “On the relative
ages of the coast Boulder-clay of the Hastern Counties, and that of the
higher ground,”! expresses his belief that there is no evidence of direct
superposition of the high-level Boulder-clay upon that of the coast.
“Tf,” says Mr. Maw, “the higher clay were more recent than the lower,
surely some cases would occur in which direct superposition was
evident. But there is no coast section exhibiting the sequence of the
high-level directly over the low-level clay, with the intervening sand
bed.” This statement excited surprise, because the author had re-
peatedly seen instances of such superposition in the cliffs of Corton
and Horton, near Gorleston, in Suffolk; and because the late Mr.
Trimmer, in a paper in the Quarterly Journal of the Geological
Society, June 17, 1857, corroborated his observations. Additional
evidence has been afforded by the recent fall of part of the cliffs at
Happisburgh. An upper and a lower Boulder-clay, with stratified
sands and clays intervening, have been exposed about a quarter of a
mile north of the Preventive Service Station, beginning where the
cliffs rise to an eminence of 50 feet, and extending three-quarters of
a mile to where they are denuded to a lower level near Ostend.
The following is the section :—
Feet.
No. 1 The Warp _... i aise 200 asc snes
2 Post-glacial sand, clay, and gravel ... ood BUM
3 Upper Boulder-clay ... 505 “08 oes SLO
4 Middledrift ... was ae ate 8
Stratified clay and sand bbe }
5 Lower Boulder-clay ... oe aoe soe cos
6 Laminated series boc adc coe 300 ooo) GS
7 Forest bed on the beach
49
This section corresponds with that at Corton, and as they repre-
sent the several strata in their normal and undisturbed condition,
the study of them may serve as a key to their highly disturbed and
contorted state near Cromer.
With respect to (No. 2) the Post-glacial sand, clays, and gravel,
from their position immediately above the upper Boulder-clay, they
might be expected to yield the remains of the Elephas primigenius ;
and such is the case. Mr. Gunn had obtained a good upper molar
from this same bed in the parish of Witton, about two miles inland.
The teeth and bones fall from these upper Pre-glacial beds upon the
beach, and become intermixed with those derived from the forest
bed, and their occurrence led the late Dr. Falconer to infer that the
E. primigenius was a denizen of the forest bed.
Mr. Gunn gave a general account of the Glacial Beds and the
Laminated Beds, and then made some observations on Mr. Taylor’s
recent researches on the Crag Fossils.
1 See Grou. Maa. Vol. LV. March, 1867, p. 97.
372 Gunn— Glacial Deposits on the East Coast.
Admitting fully the correctness of Mr. Taylor’s observations
with respect to the increasingly Arctic character of the shells found
in the Upper Crag at Bramerton, Thorpe, Horstead, Weybourne, and
other places, and also with respect to the increasing depth of the
sea in which they were deposited, he stated that a question arose as
to the position and sequence of stratification of the Forest Bed,
so rich in Mammalian remains. On the one hand, the abun-
dance of the Mastodon in the true Norwich Mammaliferous Crag:
forbids us to imagine that the Forest Bed, in which no remains of the
Mastodon have been detected, could have preceded that Norwich
crag. On the other hand, the Arctic character of the shells in the
Upper bed forbids us equally to believe that it could have succeeded
that deposit, and yet all these several beds have hitherto been
massed together under the name of Norwich Crag. This difficulty
in assigning its true position and place to the Forest Bed is greatly
augmented by the increase of depths of water in which the upper
bed of shells has been deposited. Hither the Forest Bed must have
preceded the Mammaliferous Norwich Crag, which abounded with
the Mastodon, or else there must have been oscillations of level
of land and water, and change of climate, to admit of a forest
flourishing for ages, as appears from the profusion and variety of
Mammalian remains. The only alternative seems to be to dissociate
the Mastodon Crag, which is confined to the layer of large stones
upon the Chalk, altogether from the upper beds of Crag-shells, and
to place the Forest Bed next in order above the Mastodon Crag, and
the upper beds of Crag-shells in the marine part of the laminated beds.
In justice to Mr. Searles Wood, jun., he mentioned that that
gentleman concurred in placing the Chillesford Crag and also the
upper Weybourne Crag in more recent beds than the Mammaliferous
Norwich Crag ; as recent as the Lower Drift, but Mr. Wood appears
to place the drift at an earlier period than Mr. Gunn did, and to
include the laminated beds and the Forest Bed in it, so that the
difference between their views was more nominal than real.
He had some doubts as to where to draw the line between the true
Mammaliferous or Mastodon Crag and the Upper bed; but he was
certain the Forest Bed could not have come after the Upper Crag
unless there was a change of climate or of level. He had no doubt
that the Chalk hills, upon which the Mastodon lived, remained ex-
posed as a land-surface, for a long period, and in this opinion he was
supported by Dr. and Mr. H. Woodward. The Forest Bed was a
most important stratum, as it made us acquainted with the fauna and
flora of an ancient terrestrial epoch of considerable duration.
The Rev. J. Crompton, M.A., read a paper on Lake Dwellings,
as described by Herodotus, (Lib. V. c. 16).
Cotreswotp Naturauists’ Firip-ctus.—At the annual meeting
of this Club, Sir W. V. Guise, Bart., in the chair, about thirty
members assembled. Sir William Guise was unanimously re-elected
as President. The re-election of Dr. Paine, as Honorary Secretary,
was also proposed and carried.
Cotteswold Naturalists’ Club. O73
The financial statement was passed, and some dissatisfaction was
expressed that members should allow their subscriptions to be in
arrear. :
Sir W. Guise then proceeded to read the annual address, which
was principally a reswmé of the field meetings and proceedings
of the past year. Allusion was made to a letter received by
the President from Mr. C. Moore, of Bath, on the much-mooted
question of the Infra-liassic beds of the West of England, and
which had induced the members to select Dunraven as one of
their places of meeting (on August 21st). During the disscussion
which ensued, Dr. Wright objected strongly to the term “ Infra-
lias,” and Mr. Etheridge took exception to that part of Mr. Moore’s
paper which referred to the range of Gryphea incurva, at Brocastle, but
especially at Southerndown, which he believed, after examining the
specimens, were not G. incurva, the true type of which occurs in the
Bucklandi beds above, and in those immediately succceeding the
Liassic beds in the Southerndown section. The occurrence also of
Plicatula intusstriata in the zone of “A. angulatus” should be ex-
pected; for although an abundant and typical shell in the Rheetic
beds below (everywhere in England and on the Continent), still the
persistency with which deep-sea species were found to live on,
—especially the Ostreade,—would excite no wonder that so few
were found in common even in one formation. The Brocastle and
Dunraven areas are fraught with the greatest difficulty, both on
physical and paleontological grounds. Much has yet to be done in
this area, and the Cotteswold Club are right in preparing to make
this spot the scene of one of their visits, to explore for themselves,
and look into the vexed question of the occurrence of ‘“ Muschel-
kalk” species in the so-called “ Infra-lias” beds of the West of.
England and Wales.
A paper by Professor Buckman was then read, on Roofing Tiles
of Roman date, which were discovered during some excavations at
Bradford Abbas.
At the request of the President and some of the members present,
the Rev. Mr. Symonds read a paper on the celebrated address de-
livered by Dr. Hooker, at the British Association Meeting at
Nottingham, and the opinions of that distinguished botanist on the
“Theory of the Origin of Species,” by Mr. Darwin.
Dr. Wright said that, although a consistent opponent to Darwin’s
theory on the “ Origin of Species,” he rejoiced that the days were
passed when the odium theologicum was applied to scientific investi-
gations. He then entered into his reasons for opposing the theory
on paleontological grounds, and gave an eloquent description of the
persistence of living species of corals in the Western Ocean, where
existing coral reefs were ascertained, by the careful investigation of
Agassiz, to be more than seventy thousand years old. How then did
it happen, that during all that lengthened period the species re-
mained unchanged.
Mr. Etheridge did not think Paleontology alone would solve this
intricate question : so many links were broken, so much of past life
374 Montreal Natural History Society.
lost, never to be restored. He believed that Mr. Darwin and Dr.
Hooker were right in their mode of investigation, and that the
records of Insular and Arctic floras, combined with the aid given by
fossils, may yet solve the problem which so interests every scientific
man, since the publication of Mr. Darwin’s work, and the results
arrived at by Dr. Hooker.
Monrreat Naturat History Socrmry.—The last meeting of this
body for the session of 1866-67, was held at its rooms on April 29th.
Principal Dawson read a paper “On Insects from the Carboniferous
and Devonian Formations.” Up to last year no remains of insects
had been found in the Coal-fields of Nova Scotia, except a single head
and small portions of a large insect found in the excrement of a reptile,
which, along with other animal remains, were found in the trunk of a
tree at the Joggins. This specimen seemed to indicate that the coal
reptiles were insectivoreus creatures. Last year Mr. James Barnes was
fortunate enough to find the wing of an insect, in a bed of shale at
Glace Bay, Cape Breton. Mr. Scudder, an eminent entomologist at
Boston, considers that it belongs to the Ephemera group, and that is
is a Neuropterous insect closely allied to the day and shad flies. The
insect appears to have been of large size and it seems not improbable
that this species may have haunted the swamps of the period, and
have been preyed upon by Carboniferous fishes. Wings of four
species of insects have been found by Mr. C. F. Hartt, in the plant-
bearing Devonian shales, of St. John, New Brunswick. These are
of considerable interest to the geologist, as being the oldest fossil in-
sects known; the antiquity and exact date of the beds from which
they are procured being unquestionable. These insects also belong
to the Neuroptera, and seemed allied to the Ephemera. Like many
other insects, they appear to have had a mechanical apparatus on
their wing for producing sound, the structure of which was explained
in detail. They appear to be a connecting link between the Neurop-
tera and Orthoptera.—Montreal Gazette, May 1, 1867.
CORRESPONDENCE.
DRIFT OF THE EASTERN COUNTIES.
To the Editor of the GrouocicaLn Magazine.
S1r,—There are one or two facts which I think are serious objec-
tions to the view Mr. Maw has taken as to the age of the Cromer
. beds. The first is, that there does not exist along the Norfolk coast
any such continuous margin of comparatively low ground as his paper
would seem to imply. On the contrary, some portions of the cliffs
are, I believe, as high as any part of the watershed of Hast Norfolk,
and, as a rule, higher.
For example, at Trimmingham, one of the highest points of the
coast and of the county, the spire of the Cathedral at Norwich,
standing in the valley there but a few feet above the level of the sea,
Correspondence. By)
and more than twenty miles from it in a direct line, is visible across
a comparatively low country. Iam not aware of any point inland,
equally distant, from which it can be in the same manner seen.
Other similar cases could be given. A reference to the Ordnance
maps will show that the only line of hills which presents the appear-
ance of an old coast line, at a higher level than the cliffs, is that
which runs due west from Cromer; but this is distinctly intersected
by the present coast line at the Lighthouse Hill, and certainly, the
beds under discussion do not show there any signs of disappearing.
From this point to Hasbro’ the country very often slopes inland from
the cliffs, and in a southerly direction is comparatively flat.
The rapid and unceasing encroachment of the sea along the Norfolk
coast should also be remembered. Mr. Gunn gives an instance where
ninety yards of the cliff have been swept away in thirty-five years ;
and I do not know any reason why this may not have been going on
at a more or less rapid rate, perhaps from the very commencement
of the present period. It will be thus seen that the present coast-
line is a purely accidental one, and cut across what may have been
once almost the centre of the county.
A very satisfactory reason can be given for the absence of the
Boulder-clay (upper drift) from the coast section between Hasbro’
and Weybourne; and that is, it has been completely denuded from
the northern part of the county, as shown in Mr. Wood’s map.
J am not aware of a single outline existing north of a line joining
Hasbro’, North Walsham, and Holt. J ought to say that Mr. Gunn
thinks the Upper Drift does appear in the cliffat Hasbro’. I am
sorry that I am unable to agree with him in this, but if it does occur
there, it settles the question.
I am, yours truly,
F. W. Harmer.
Hxicuam Grove, Norwicn,
June 4, 1867.
To the Editor of the Grotocican MaGazine.
Sir,—All I need say in reference to Mr. Maw’s remarks is, to
suggest that he give some sections drawn from his supposed high
level Boulder-clay to that on the coast. I do not mean a hypothetical
section like that at page 98, of vol. iv., but actual sections drawn to
not less than half the horizontal scale of the Ordnance map (half-inch
to the mile), and showing all the places marked on that map along the
line taken. ‘To have any value at all, such sections should show every
bed, from the Crag upwards, that may come to the surface en route.
Of these sections, two at least would be required: one from Norwich
to some part of the coast section between Hasboro’ and Weybourne ;
and another from Norwich to the Boulder-clay of Pakefield and
Corton cliffs.
I hope that Mr. Taylor may succeed in obtaining recognizable
specimens of shells from the Middle Glacial beds, so as to afford the
means of comparison with those obtained from Macclesfield; for
although I have examined hundreds of sections in this formation,
376 Correspondence.
from Leicester to Chelmsford, and from Buckingham to the Hast
Coast, I never until lately succeeded in obtaining a reliable shell.
I recently, however, found two perfect specimens of Ostrea edulis in
the Middle Glacial gravel, above the Brick-clay, in the disused brick-
field at Stevenage. Any one having local opportunity would do
good service by hunting this locality before the field is levelled and
closed up, which is now being done.
As QO. edulis is not an arctic shell, and occurs as far south as
Gibraltar, its presence, as far as it goes, accords with the other
characters of this formation in shewing that the Middle Glacial was
not an arctic deposit.
Yours faithfully,
Suartes V. Woop, Jun.
BRENTWOOD, Essex, June 7, 1867.
P.S.—The obscure specimens of shell obtained from Saxlingham,
Mr. Taylor will, I think, find belong, not to the Middle Glacial, but
to the Chillesford beds (7.e. his Upper Crag), which are present
there in a feeble form resting on the Chalk. Those obtained by him
from Sprowston I presume are from the Middle Glacial sands, as
the Upper Drift does not occur, to the best of my knowledge, at, or
within, some four or five miles of that place. Perhaps, however,
he may refer to some small outlier that Mr. Harmer and I have
missed, or, possibly “Upper” may be a misprint in his letter for
““ Lower.”
ON THE NATURE OF EOZOON,
To the Editor of the Grotocican Magazine.
Str,—Having been engaged for some time on a paper on classifi-
cation, with especial reference to the Mollusca, I had already in the
introductory part of it written the greater part of what follows when
I read in the Guotoeican Macaztne an abstract of a memoir by Dr.
Dawson on Hozoén. As it may be some time before my paper just
referred to is ready for publication, I send you this part of it at once.
It will doubtless be some time before the true relations of Hozoén
Canadense are finally settled. But before Mr. Hancock’s paper on
“ Boring Sponges’! appeared, I was decidedly of opinion that the
Kozoin had nearer relations with the Sponges than with the Fora-
minifera. That paper has quite confirmed me in this view; for Mr.
Hancock shows the great similarity which exists between the dis-
position of the cells and sarcode in Cliona and Orbitoides. The latter
genus was chosen by Dr. Carpenter for comparison with Eozoén to
show the foraminiferal nature of the latter, and Mr. Hancock might
fairly have carried on his comparison to Hozoén. Any one who
compares the figures accompanying Dr. Carpenter’s memoir on
Eozoén in the Quarterly Journal of the Geological Society with Mr.
Hancock’s diagram of Cliona, will not fail to be struck by the simi-
larity. Doubtless the Hozoén is allied to Rhizopoda as well as to the
1 Ann, and Mag. Nat. Hist., 3rd ser. vol. xix. p. 229,
Correspondence. 377
Sponges. And this is precisely what we might expect in so ancient
a form. For it is well known that the more ancient forms often
blend the characteristics of types, or as Dana expresses it, they are
‘comprehensive types.” In this way Hozodn may, to some extent,
comprehend the characters of Rhizopoda and Spongiade. Without
committing myself, however, to all the generalizations, frequently
extremely hazardous, of the celebrated American geologist, I may
remark that all this is perfectly compatible with the doctrine of
descent with modification, and that that hypothesis is the only one
yet propounded which satisfactorily explains these alliances.
I find myself completely borne out in my views on the nature of
Hozoén by the discovery by Principal Dawson of siliceous spicules in
the cells of that organism. It is true, that able paleeontologist attri-
butes these spicules to a sponge which has filled the cells of Hozoén
subsequently to the death of the latter. But I think, in view of the
resemblance between the structure of Hozoén and that of the boring
sponges, that the hypothesis of Dr. Dawson is wholly unnecessary,
and that there is no difficulty in attributing the spicules to the Hozoon
itself.—I am, Sir, your obedient servant,
R. Lecumere Guppy.
Port-oF-Spain, TRINIDAD,
ord June, 1867.
SHELLS ON THE GREAT ORMESHEAD.
To the Editor of the Grotocican Maeazine.
Dear Sir,—In the paper on “ Glacial Action near Llandudno,” in
the July number of the Magazine, Mr. Bonney (page 290) notices
the occurrence, in the surface deposit at Gwydfyd, on the Great
Ormeshead, of quantities of shells. It is worthy of remark that
there are none but those of eatable species,—Patella vulgata, Inttorina
littorea, Mytilus edulis, Ostrea, and Tapes. I obtained examples here
in November, 1864, when their extreme profusion, and the way in
which they occurred, convinced me that they had been brought there
by the hand of man. I find from a section I made at the time, from
the pier at Llandudno to the top of the Ormeshead, that the shell
bed occurred at a height of 380 feet above the sea. The accumula-
tions of the subaérial loam which covers it would seem to imply
very great antiquity in relation to the human period; but it is evi-
dently quite a different deposit to the Boulder-clay that occurs on
the coast at the bottom of the valley, here limited to a range of about
170 feet above the sea (it terminates close to the lowest fence).
Similar clay with transported boulders forms a terrace of about
the same height on the south side of the Head, and attains a some-
what greater elevation on the flanks of the Little Ormeshead.
Whilst suggesting that the Gwydfyd shell-bed is of artificial
origin, I do not wish to call in question the evidence Mr. Bonney
brings forward in proof of Glacial action, as drift with transported
and striated boulders is abundant in the neighbourhood, especially
on the east side of Orme’s Bay. There is also a good section con-
378 Correspondence.
taining shells about midway between the Bay and Bryn Gosol, not
far from the turnpike-road. Whilst referring to this district, Mr.
Mackintosh’s paper suggests my pointing out an example of a higher
coast level, as indicated by Pholas-borings. A friend informs me
that he has seen these markings high up on the mountain to the
west of Conway, but I have no record of their exact altitude.
Referring to Mr. Green’s letter, I would remark that the Llandudno
district affords clear evidence of the superposition of Glacial drift on
the white sands or clays resting on the Carboniferous Limestone ;
though, it must be admitted, this is not so obvious in Staffordshire.
Regarding the source of materials, the broken chert beds that are
near Llandudno associated with these deposits, seem to indicate a
derivation from the Millstone Grit which, along the north coast of
Wales, contains extensive beds of chert. The Bunter beds in North
Wales are so invariably red that I scarcely think it probable they
can have supplied any materials for the white beds underlying the
Boulder-clay drift in that district.
Grorce Maw.
BentHaLt Hatt, Broseey,
July 2nd, 1867.
SOME REMARKS ON THE REPORT OF PROFESSOR OWEN’S PAPER
ON FISH REMAINS FOUND IN THE NORTHUMBERLAND
COAL-FIELD.!
To the Editor of the GrotocicaL MAGAZINE.
Srr,—I beg to be allowed to make a few remarks on the Report
which appeared in the July number of the GrotocicaL Macazine of
Professor Owen’s paper, “‘On the Dental characters of Genera and
species, chiefly of fishes, from the Low Main Seam and shales of
coal, Northumberland,” (read before the Odontological Society on
the 3rd of June last). ;
I have been engaged for many years in collecting fish and other
remains from the Northumberland Coal-field, and have obtained a vast
number of specimens, both entire and fragmentary, from the shale in
connection with the Low Main Seam at Newsham, West Cramlington,
and other places. Mr. T. Craggs, who was cognizant of my oper-
ations, gathered, a short time ago, a few specimens of fish-remains,
principally teeth, from the same localities; and sent prepared micro-
scopical sections of some of them to Professor Owen, who has, from
these materials, described twelve or thirteen new genera, several of
which I believe to be founded upon remains previously described,
while others are, apparently, the result of an examination of the
varied sections of the same forms.
I believe there are no remains noticed in Professor Owen’s list, so
far as the concise account in the Report enables me to judge, of which
there are not numerous specimens in my collection; and as I have
had the advantage of examining these under varied conditions—not
merely of sections—I am in a position to speak with some degree of
1 See Grou. Maa., July, p. 323.
Correspondence. 379
confidence on the subject, having made numerous sections of them
in well-determined planes. The specimens submitted for exami-
nation appear to have been all very minute examples of their
respective kinds, or Prof. Owen would not, I feel sure, have asserted
that these “minute fishes” were “ of the size of minnows or stickle-
backs.” Most of these remains have belonged to fishes of no incon-
siderable size, some of them, I believe, to the largest fishes of the
Coal-measures. The following genera, proposed by Professor Owen,
seem to require particular notice :-—
Genus I. Dittodus.—This is undoubtedly Diplodus of Agassiz,
and is not a tooth but a dermal spinous tubercle.—I have in my
collection vast numbers of such, some detached, others in connection
with a thin layer of granular matter, which there can scarcely be
any doubt is the skin of some fish. One of these patches in my
possession is fifteen inches long and about seven wide. On this the
tubercles are comparatively few, and are scattered far apart from each
other. But on another patch, measuring fifty-six inches square, they
are very numerous, and are crowded together without any apparent
order.
These tubercles are analogous to the spinous dermal tubercles found
on some of the Rays, only in the Ray there is but one spine, while in
that under consideration there are usually three, sometimes two, and
rarely only one; when three are present, one is always much smaller
than the other two, and rises from the common bony base behind
them and opposite to the space between them. So that in making a
section to exhibit the two principal spines it is almost impossible to
preserve the small posterior one; consequently it happens that only
the two large spines are seen united at the base—‘‘the two crowns”
as Professor Owen expresses it, being “organically connected to-
vether, like the Siamese-twins.”
Diplodus varies very much in size, being occasionally quite micro-
scopic, and not unfrequently measuring nearly three-quarters of an
inch in length. It also varies considerably in character, the spines,
or ‘crowns’ being frequently long, nearly parallel, and compara-
tively slender; occasionally they are found diverging, short, stiff,
and much bent ; numerous specimens occur having characters inter-
mediate to the two extreme forms; there can, therefore, be no doubt
that Dittodus parallelus and D. divergens are mere varieties, the one
of the other.
Genus II. Mitrodus.—This, I believe, will also prove to be a der-
mal tubercle. There are occasionally found in the Low Main shale
thin layers or patches almost entirely composed of minute compressed
bodies, having rising up from their upper or free margin from two to
seven conical denticles, which answer very correctly to the account
given of this form. I possess such a patch measuring 20 inches long
and 13 inches wide. It is spread over with vast multitudes of these
tubercular bodies, which are crowded together in a confused manner.
Detached specimens of the tubercles also occur.
These tuberculated patches are usually associated with the spines
and other remains of Gyracanthus, and are most probably the skin
380 Correspondence.
of that fish. Thus it would appear that Mitrodus, instead of be-
longing to a fish of the size of a minnow, is most likely part of
one of the largest, if not the very largest, fish of the Coal-measures.
Dittodus too—as the size of the dermal patches proves—was an
animal of no mean dimensions.
Genus III. Ageleodus.—This is the Ctenoptychius of Agassiz. It
occurs of various sizes, and is sometimes minute; but it is fre-
quently upwards of three-tenths of an inch wide, and is usually
found detached, though sometimes two are placed end to end; this
form has also much the appearance of being a dermal tubercle
rather than a tooth. It is much compressed, and the spines, or
‘dental crowns,” which vary in number from six to sixteen, give to
the upper margin a saw-like denticulation. The bony base, giving
support to the denticulated portion is, of considerable extent, and has
all the appearance of the basal limb of a dermal tubercle.
Genus IV. Ganacrodus.—Teeth tipped with enamel are very com-
mon in the shale of the Low Main Seam; they vary greatly in size,
though not in other respects, but when seen in section they seem to
differ considerably. Their apparent curvature depends entirely on
the plane of the section, and the point becomes more or less obtuse
as this is further from, or nearer to, the axis of the tooth. The
apparent extent and form of the enamel-tip also varies much in
accordance with the section. Some specimens are entirely coated
with a thin film of enamel; in others, traces of it only can be ob-
served ; and in some again, it seems entirely wanting, owing
apparently to the state of preservation of the specimen.
FE have little hesitation in saying that all these teeth tipped with
enamel found in the shale overlying the coal of the Low Main
Seam at the localities before-mentioned, belong to Palzoniscus—the
teeth of which genus are always thus tipped with enamel, as I have
satisfied myself by sections of several jaws, with the teeth attached,
taken from well authenticated specimens.
That Palgoniscus occurs abundantly in this shale I have ample
proofs, having taken from it well preserved individuals of this
genus, besides numerous fragmentary specimens. The teeth of
Amblypterus and Pygopterus are likewise tipped with enamel, but the
latter genus has not yet been found in the localities named,
Amblypterus is very rare: the tooth of Pygopterus is extremely
characteristic, and is readily distinguished by the obtuseness of the
terminal enamel.
The teeth of Palgoniscus vary much in size in the same individual,
some being quite microscopic, others comparatively very large.
The minute ones are exceedingly numerous, and much crowded; the
larger are few in number, and considerably apart from each other.
Genus V. Ganalodus .—There are two of this number. Genus 5,
Mioganodus, and Genus 6, Aganodus, are probably all founded on
teeth belonging to either Palgoniscus or Amblypterus, both of which
genera occur in the shale connected with the Low Main.
Genus VII. Pternodus.—When a single spine of Diplodus is ob-
served in lateral section, it has a heeled appearance, and in other
Correspondence. 381
respects agrees with the characters of this genus, so far as they are
given in the Report. The variety of Diplodus with a single spine
also exhibits the same peculiar feature.
The characters of the four other genera, described in the paper,
are too concisely given in the Report to enable me to form any
decided opinion respecting them, though I venture to think that
more than one are apparently only varieties of previously described
forms.
THomas ATTHEY.
GasFortH, NEWcASTLE-oN-TYNE,
July 15, 1867.
THE WEAVER CLAYS.
To the Editor of the GrotocicaL MAGAZINE.
Srr,—When I paid my first visit to the Ribden Fire-clay Pit
several years ago, I formed pretty much the same opinion as that
now held by Mr. Green, viz., that the deposit consisted of local
washings from surrounding strata, gathered into a wide fissure.
I have since then, however, made many journeys to the district,
and I have convinced myself, from a leisurely examination of all
the openings which have been made in search of “clay,” that the
deposit is a very extensive one, and truly of marine origin. The
beds extend over an area of nearly two miles in length, with a
width varying from a quarter of a mile to a mile and a half.
Mr. Green is in error in attributing the parentage of the sands
and clays to the Bunter. The greater portion of the deposit has
certainly been derived from the Millstone grit strata that still pre-
vail so largely to the westward of Weaver. Immense blocks of
grit, of different degrees of hardness and coarseness, are thickly
embedded in the sands at Caldon Low, and they are to be seen in
every state of degradation, from the- hard unperished stone to in-
coherent sand, that merely shows where the blocks previously
existed, by a slight difference of tint from that of the sand of the
matrix. A very small percentage only of the sands of the deposit
have been derived from the Bunter.
The sands in some parts of the deposit are as white as the best
Alum Bay sand. They are so free from iron that, at my recom-
mendation, they have been tried lately for glassmaking, and they
have been found to answer very well. Bunter sand could scarcely,
under any circumstances, have beén washed sufficiently free from
iron to stand this manufacturing test.
With regard to the “ Boulder-clay Drift,” I must state it to be my
firm conviction that the red bed which overlies the “‘ Weaver Clays,”
in some parts to the thickness of from twelve to fifteen feet, does
really belong to that formation. It lies in many places where it
could not have been deposited by subaérial action; it contains
rounded and subangular masses of stone of many formations, and it
has itself been subjected to after-denudation. It is also of similar
character to the red clay that is seen to fill the fissures in Caldon
Low, at a height of twelve hundred feet; and to be piled on the
382 Correspondence.
floor of Thor’s Cave, at about nine hundred and fifty feet above the
sea-level.
I do not understand Mr. Green’s hesitation to admit that the sea
covered the Derbyshire Limestone Hills at the Glacial epoch, for I
read in the valuable Ordnance Memoir of the country round Stock-
port, Macclesfield, Congleton, and Leek, by Messrs. Hall and Green,
and with the paragraph itself bearing the initials A. H. G., that
“Tn an outlying patch of sand and gravel about three miles from
Macclesfield, on the Buxton road, at a height of about twelve hun-
dred feet above the sea, Mr. Prestwich found shells; and Mr.
Sainter tells me that he has collected there Turritella, Cardium edule,
and others.” Now the point on the Axe Edge range here indicated
is only about sixteen miles from Weaver, and the highest tops of
the Weaver range are not more than about twelve hundred and twenty
feet above the sea; the Weaver Clays and the Boulder Drift, the
subjects of the present communication, lying at from one thousand
to one thousand and fifty feet.
We have not yet found shells in the drifts of the neighbourhood ;
but we have every other proof that can be desired of their marine
origin.
The chief geological interest that attaches to the ‘‘ Weaver Clay ”
deposit is, that it proves a submersion of this part of the country
at, some period between the Triassic and the Boulder-clay epochs, at
which latter period our hills were undoubtedly again sunk beneath
the sea. T am, Sir, Yours faithfully,
| Epwin Brown.
BuRTON-UPON-TRENT.
12th July, 1867.
THE LOB-WORM EPOCH.
To the Editor of the GzotocicaL MAGcazine.
Srr,—Mr. Baily (Figures of Characteristic British Fossils, p. 12)
tells us that the only remains of animals in the Cambrian rocks (the
oldest fossiliferous British strata) are those of worms; and (p. 3)
that these worms were ‘allied to the recent lob-worm.” It-is true
that he remarks (p.12) that “it has been argued, and with reason,
that this apparent paucity of organic remains may have arisen from
the nature of the deposit . . . and that there may have been a more
varied assemblage of life during this epoch . . . as this, however, is
necessarily conjectural, much importance cannot be attached to it.”
Now is the negative argument not also “conjectural ?” and is it not
a most absurd conjecture that because in certain marine strata, in a
certain place in England, signs of no life are found save that of
worms, that in the ‘‘epoch”’ or time when those strata were formed
no animals existed on the terraqueous globe save worms? Is this
not “conjectural?” and most absurdly conjectural? Continents
from the denudation of which the Cambrian strata were formed
must have existed for countless millions of years. And were these
continents, and the land, and the water, of the whole terraqueous
globe uninhabited, except by marine lob-worms? ‘This is a curious
Obituary. | 383
conjecture. And it is founded on the most ridiculous confusion
between space and time, between place and period, as I have
argued throughout “‘ Rain and Rivers.”
Mr. Baily will not, I am sure, think that I intend to attack him.
I attack the received doctrine which Mr. Baily supports ; and I must
confess that I am the twelfth juryman who complained of his eleven
obstinate compeers.—I have the honor to be, Sir,
Your most obedient, and most obliged,
GroRGE GREENWOOD, Colonel.
Brookwoop Park, ALRESFORD,
19th July, 1867.
@ is ae OPA.
ESE
Witttram Joun Hamitton, F.R.S., G.S., erc.—lIt is with sincere
regret that we have to record the loss which the science of geology,
very many personal friends, its cultivators, and, above all, the
Geological Society of London, has sustained by the premature
decease of Mr. William Hamilton, a loss which can be but very
imperfectly replaced, owing to his long official connexion with that
Society, and his accurate knowledge of its affairs. Mr. Hamilton
became a member of the Geological Society in 1831, and in the
following year was elected one of its honorary secretaries, which
office, or else that of Foreign Secretary, he continued to occupy
almost uninterruptedly till 1854, when he was elected its President.
Mr. Hamilton’s first contribution to geology dates back to 1835,
from observations made in the previous year, and relates to the
proofs of recent elevation of the land, which he had observed on the
coast of Fifeshire. About this time, and, as is generally understood,
at the suggestion of the present Sir R. Murchison, Mr. Hamilton
formed the plan of an extended foreign tour for the purpose of
studying the phenomena of physical geography and geology ;
through him also he became acquainted with the late Mr. Hugh
Strickland, which resulted in their becoming fellow travellers; the
partnership was a judicious combination, and Mr. Hamilton con-
stantly acknowledges the value of Mr. Strickland’s great knowledge
in various branches of natural history.
The limits of such a notice as the present preclude even a sum-
mary of Mr. Hamilton’s travels. They were commenced in the
summer of 1835. Beginning with the extinct volcanic districts and
old lacustrine areas of the Mont Dor and the Vivarais, as prepara-
tory to visiting those of Asia Minor, they thence passed by the
North of Italy, Trieste, Corfu, Patras, Corinth, Athens. They
reached Smyrna by the end of October, having visited much that
was of interest on their way. Mr. Strickland was called back to
England in the early part of 1836, after which Mr. Hamilton con-
tinued his travels alone, hut some papers, the results of their joint
observations, were communicated to the Geological Society.
The summer of 1836 was spent in the country to the south of the
Black Sea, returning to Smyrna by November. He then accepted
384 Obituary.
the offer of Mr. J. Brooke (now Rajah Brooke) of a cruise in the
« Royalist,” along the coasts of Ionia and Caria to Rhodes. This
occupied till February, 1837, when, starting again from Smyrna, he
visited for the second time the Katakecaumene, of which he gave an
account, which was published in the transactions of the Society, as
also another memoir on the Eastern portion of Asia Minor. The
objects of Mr. Hamilton’s travels were not, however, exclusively
geological. The results were given in two volumes, as ‘Researches
in Asia Minor: Pontus and Armenia, their Antiquities and Geology,”
to which reference must be made before a just estimate can be
formed as to Mr. Hamilton’s qualifications as an enterprising and
accomplished traveller. The objects proposed were successfully
carried out, and so far as he himself was concerned, the Hastern
tour served to realize what as yet was undeveloped, gave him habits
of observation, and of applying the varied education he had received,
created a power of clear narration, and finally assigned to him a
high position among modern English travellers. He possessed all
the qualities which go to form a good traveller; he was unselfish,
always adapting himself readily to circumstances, and a good com-
panion ; moreover, he was an accomplished linguist. Spanish,
French, Italian, and German were as familiar to him as his own
language.
Mr. Hamilton was elected President of the Geological Society for
the second time in 1865. His later contributions to Geology were
on Tuscany, and the best account that has yet been given of the
Eocene basin of Mainz was the result of his examination, and of
the large collection of the fossils he formed there in 1852. For
some years he had devoted much time and expense to recent con-
chology, under a sense of the dependence of the history of the “Tertiary
period” of geologists, on a knowledge of existing forms of shells, and
their geographical distribution, with which objects in view he had
already formed a very large collection. It was in the hope that he
might some day turn this knowledge to the service of geology that
he joined in the excursions which several of his fellow members of
the Geological Society made into the districts of the Faluns of
Touraine, and of the crag of Antwerp.
Mr. Hamilton was an active Fellow of the Royal Geographical
Society—he was elected president for the years 1848 and 1849, and
has served on the Council for many years. He contributed the
article, “‘ Geography ” to the Admiralty Manual of Scientific Inquiry,
edited by Sir John Herschel.
Mr. William Hamilton was the eldest son of Mr. Hamilton, some-
time British Minister at Naples, and author of Aigyptiaca; was born
in 1805, educated first at the Charter House, and subsequently at the
University of Gottingen. At the outset of his career he served in
the foreign Diplomatic Service at Madrid, Paris, and Florence. He
was précis writer at the Foreign Office under Lord Aberdeen, and
resigned it on his election for Yarmouth. Mr. Hamilton was twice
married; his second wife, who survives, was the Hon. Helena Dillon,
youngest daughter of Viscount Dillon.—R. G-A.
E
GEOLOGICAL MAGAZINE.
No. XXXIX.—SEPTEMBER, 1867.
Ose GaN Aa Ae ce ae ae Sy
SSS
1.—On Some Remains or Patmozoic INSECTS RECENTLY DISCOVERED
In Nova Scorta anp New Brunswick.
By J. W. Dawson, LL.D., F.RB.S., F.G.S.,
Principal of McGill’s College, Montreal, Canada.
(PLATE XVII. FIGS. 1-5.)
connection with the preparation of the second edition of “‘ Acadian
Geology,” I have obtained, from friends who have been engaged
in geological investigations in Nova Scotia and New Brunswick, some
interesting illustrations of the entomology of the Carboniferous and
Devonian Periods, which I have thought it might be useful to publish
in advance of the appearance of my work.
1. Carboniferous Insects—The existence of insects in the Carboni-
ferous period has long been known. The Coal-formations of England
and of Westphalia afforded the earliest specimens ; and, more recently,
some interesting species have been found in the Western States.!
They belong to the orders Neuroptera (shad-flies, etc.), the Orthoptera
(grasshoppers, crickets, ete.), and Coleoptera (beetles, etc.).
In the Coal-field of Nova Scotia, notwithstanding its great richness
in fossil remains of plants, insects had not occurred up to last year,
except in a single instance—the head and some other fragments of a
large insect, probably Neuropterous, found by me in the coprolite or
fossil excrement of a reptile enclosed in the trunk of an erect Sigil-
laria at the Joggins, along with other animal remains. This speci-
men was interesting, chiefly as proving that the small reptiles of the
Coal-period were insectivorous, and it was noticed in this connection
in my “ Airbreathers of the Coal-period.” Last year, however, Mr.
James Barnes, of Halifax, was so fortunate as to find the beautiful
wing represented on Plate XVII., Fig. 1, in a bed of shale, at Little
Glace Bay, Cape Breton. The original engraving was taken from a
photograph kindly sent to me by Rev. D. Honeyman, F.G.S. It
will be observed that in consequence, probably, of the mutual at-
traction of loose objects floating about in water, a fragment of a frond
of a fern, Alethopteris lonchitidis, lies partly over the wing, obscuring
its outline, and bearing testimony to its Carboniferous date. The
wing has been examined by Mr. Samuel H. Scudder, of Boston, who
has made such specimens his special study, and who refers it to the
! See Lyell’s Elements, and Dana’s Manual, for references.
VOL. 1Y.—NO, XXXIX. 26
386 Dawson—On Paleozoic Insects.
group of Ephemerina (day-flies, shad-flies) among the Neuroptera,
and has named it Haplophlebium Barnesti. It must have been a very
large insect—seven inches in expanse of wing—and, therefore, much
exceeding any living species of this group. When we consider that
the larvee of such creatures inhabit the water, and delight in muddy
bottoms rich in vegetable matter, we can easily understand that the
swamps and creeks of Carboniferous Acadia, with its probable mild
and equable climate, must have been especially favourable to such
creatures, and we can imagine the larve of these gigantic Ephemeras
swarming on the deep black mud of the ponds in these swamps, and
furnishing a great part of the food of the fishes inhabiting them,
while the perfect insects, emerging from the waters to enjoy their
brief space of aerial life, would flit in millions over the quiet pools
and through the dense thickets of the Coal-swamps. Mr. Scudder
describes the species as follows :—
Haplophlebium Barnesti, Scudder (Plate XVII. Fig. 1).—This is
probably one of the Ephemerina, though it differs very much from
any with which I am acquainted. The neuration is exceedingly
simple, and the intercostal spaces appear to be completely filled with
minute reticulations without any cross-veins. The narrowness of
the wing is very peculiar for an Ephemeron. The form of the wing
and its reticulation remind me of the Odonata, but the mode of vena-
tion is very different; yet there is apparently a cross-vein between
the first and second veins in the photograph (not rendered in the
cut) which, extending down to the third vein, occurs just where the
‘‘nodus ” is found in Odonata, and if present would, unquestionably,
remove this insecct to a new synthetic family between Odonata and
Ephemerina. I cannot judge satisfactorily whether it is an upper or
an under wing. The insect measured fully seven inches in expanse
of wings—much larger than any living species of Hphemerina.
2. Devonian Insects.—The only known remains of insects of this
age are the wings of four species found by Mr. C. F. Hartt, in the
plant-bearing Devonian Shales of St. John, New Brunswick. The
figures now given of these remains, taken from drawings made by
Mr. Scudder, though they represent fragmentary specimens only, are
of the highest interest, as the most ancient remains of insects known
to us, and contemporary with the oldest known land flora; their age
being probably about that of the Hamilton or Chemung formations
of New York. :
Their geological date is unquestionable, since they are found in
beds richly stored with species of Devonian plants, and unconform-
ably underlying the oldest portion of the Carboniferous series.
These beds are fully described in a paper by Mr. Matthew, in
the “Quarterly Journal of the Geological Society of London,” and
also in Professor Bailey’s “‘ Report on the Geology of Southern New
Brunswick ” — “Appendix A, on the Devonian Plant locality of
Lancaster, by Mr. C. F. Hartt.”
These insects, it will be observed, are of older date than the Car-
boniferous species previously noticed, and they bore the same relations
to the land and the water of the Devonian which the former did to
Dawson—On Paleozoic Insects. 387
those of the Carboniferous period. They were all Neuropterous
insects, and allied to the Ephemeras. It is interesting, however, to
observe that, like many other ancient animals, they show a remark-
able union of characters now found in distinct orders of insects; or
constitute synthetic types, as they have been termed. Nothing of this
kind is more curious than the apparent existence of a stridulating or
musical apparatus like that of the cricket, in an insect otherwise
allied to the Neuroptera. This structure also, if rightly interpreted
by Mr. Scudder, introduces us to the sounds of the Devonian woods,
bringing before our imagination the trill and hum of insect life that
enlivened the solitudes of these strange old forests. Mr. Scudder has
kindly furnished descriptions of these insects as follows :—
Platephemera antiqua, Scudder (Plate XVII. Fig. 2).—The direction
of the principal nervures in this insect convinces me that it belongs
to the Ephemerina, though I have never seen in living Ephemerina so
much reticulation in the anal area as exists here—so, too, the mode
in which the intercalary nervules arise is somewhat peculiar. It isa
gigantic species, for it must have measured five inches in expanse of
wings—the fragment is a portion of an upper wing.
Homothetus fossilis, Scudder (Plate XVII. Fig. 3).—At first sight
the neuration of the wings of this insect seem to agree sufficiently
with the Stalina to warrant our placing it in that family ; but it is
very interesting to find, in addition to minor peculiarities, that near
the base of the wing, between the two middle veins, there is a heavy
cross-vein from which new prominent veins take their rise ; this is
characteristic of the Odonata, and of that family only. We have,
therefore a new family representing a synthetic type which combines
the features of structure now found in the Odonata and Sialina, very
distant members of the Newroptera. The fragment is sufficiently
preserved to show the direction, extent, and mode of branching of
nearly every principal nervure. It is evidently a portion of an
upper wing ; the insect measured not far from three and a half inches
in expanse of wings.
Lithentomum Harttii, Scudder (Plate XVII., Fig. 4).—This was
the first specimen discovered by Mr. C. F. Hartt. I have therefore
named it after him. Apparently it does not belong to any family of
Neuroptera represented among living forms. It agrees more closely
with the family Hemeristina, which I founded upon a fossil insect
discovered in Illinois, than it does with any other; but it is quite
distinct from that, both in the mode of division of the nervures and
in the peculiar cross-veining. The fragment which Mr. Hartt dis-
covered is very imperfect; but, fortunately, preserves the most
important part of the wing. I am inclined to think that it was a
lower wing. The insect probably measured three and a half inches
in expanse of wing.
Xenoneura antiquorum, Scudder (Plate XVII., Fig. 5).—Although
in this fragment we see only the basal half or third of a wing, the
peculiar mode of venation shows that the imsect cannot belong to
any known family of Neuroptera living or fossil ; yet it is evidently
a Neuropterous insect. In addition to its other peculiarities there is
388 Kirkby—Insect-remains from the Coal.
one of striking importance, viz., the development of veinlets, at the
base of the wing, forming portions of concentric rings. I have
endeavoured in vain to explain these away as something foreign to
the wings, accidentally introduced upon the stone, and I know of
nothing to which it can be compared but to the stridulating organ of
some male Orthoptera! It is difficult to tell whether the fragment
belongs to an upper or an under wing. Its expanse of wings was
probably from two to two and a half inches.
EXPLANATION OF PLATE XVII.—(Fies. 1-5).
Fig. 1.—Haplophlebium Barnesii, Scudder. Coal-shale, Little Glace Bay, Cape
Breton, Nova Scotia. a. Profile of base of wing.
2.—Platephemera antigua, Scudder.
», 3-—Homothetus fossils, Scudder.
4,.—Lithentomum Harttii, Scudder.
» 0-—Xenoneura antiquorum, Scudder.
Figs. 2-5 all from Plant-bearing Devonian shales, St. John’s, New Brunswick.
Tl.—On toe Remains or Insects FRoM THE CoAt-MEASURES OF
DurHam.
By James W. Kirxsy.
(Plate XVII., Figs. 6-8.)
S the remains of insects are rarely found in Carboniferous strata,
a short account of three imperfect specimens, which have been
discovered in the Durham coal-field, may not be deemed valueless.
Indeed, with the exceptions of the specimens described from Coal-
brook Dale by Prestwich,’ twenty-five years ago, and the examples
of Xylobius sigillaria of Dawson,—discovered by Mr. Tindall, in the
Lower Coal Measures, near Huddersfield,? and by Mr. Thomas
Brown, of Stewarton, in the Upper Coal Measures of Kilmaurs,3—I
am. not aware of any other fossils of this class having been noticed
as occurring in Carboniferous rocks in England.
The fossils under notice were found on the north bank of the
Wear, opposite to Claxheugh, about two miles west of Sunderland.
An upcast fault to the east brings into section a few of the higher
beds of the coal-field, which the wash of the river has exposed in a low
drift-covered cliff. About sixty yards from the fault there appears a
few feet of dark-grey, compact, and fissile shale, containing three or
four thin and irregular bands of clay-ironstone, from one of which
the insect remains were obtained.
As the throw of the fault does not exceed seventy or eighty feet,—
the upper portion of the Lower red Permian sandstone being the
surface rock on the west side of the dislocation,—the position of the
bands of ironstone cannot be very far below the base of the Permian
series. Moreover, as the measures of this coal-field attain their
maximum thickness in the vicinity of Sunderland—being more or
1 Geol. Trans. 2nd Series, 1842, Vol. v., p 440.
2 Trans. Lit. and Phil. Soc. Manchester, January 8th, 1867 ; and Grou. Maa.,
Vol. LV., No. 33, 1867, p. 1382.
3 Grou. Maa., March, 1867, p. 130.
Geol. Mag. 1867. Mol Pl. XVII.
a
ain
NS
CENANG
\
Oo x
ENG
SK
AS
UUs
3 Rann ss
Ni arses
i
ZG, yy YELL LLM LE !
== ea
‘ S : iy aes pak en He |
oe Oe,
tty
TA
G. R. De Wilde, fecit. | “Hailes & Co., Imp.
ENGLISH & CANADIAN PALAZOZOIC INSECT-REMAINS.
Kirkby—Insect-remains from the Coal. 389
less denuded immediately to the north, west, and south—the iron-
stone must occupy a position very near to the top of the Coal-
measures as developed in Durham and Northumberland.
I have, fortunately, been able to submit the specimens to the
inspection of a good entomologist, Mr. T. J. Bold, whose observa-
tions thereon are freely used in the following brief descriptions.
The specimens drawn on Plate XVIL., Figs. 6, 7, evidently belong
to one species. The first is a very fine distinct example of the anterior
portion of the fore-wing of an Orthopterous insect, which in form and
neuration agrees generally with that of the recent genus Blatta ; but
although we have here the same produced, flattened fore-edge, much
the same shaped disk, and lobed inner angle, still the sculpture
between the nervures differs from that of the recent type, and
approaches more nearly to that of the Mantide.
It is not unlikely that this fossil may prove identical with one of
the species of Blatta or Blattina described by Germar’ and Golden-
burg? from the Carboniferous strata of Wetting, in Westphalia, and
Saarbriick, near Treves, good figures of which I have not seen. To
one of these, Blattina primeva, Jordan, it certainly approaches very
closely, so far as may be judged from the woodcut given by Dana in
his Manual of Geology, at page 357.
The shuttle-shaped specimen, Plate XVII., fig. 8, is difficult to
determine. It approaches nearest in shape and neuration to the
abortive anterior wing of some of the Phasmide, which are also
Orthopterous insects; but it is impossible from such imperfect
materials to speak with certainty on its affinities.
The combination of characters at present peculiar to distinct
generic types, which is exemplified in fig. 6 in its double affinity to
Blatta and Mantis, has been noticed previously in Paleozoic insects.
Mr. 8. H. Scudder has drawn attention to the fact, as being highly
characteristic, of some remains of insects found in the Devonian
rocks of New Brunswick, as well as of the other remains of the same
class from the Carboniferous strata of Illinois. He observes that
not only do some of these fossil species partake of the characters of
different recent genera and families, but sometimes they unite those
of two orders, as, for instance, those of the Orthoptera and Neuroptera.
Of course the existence of such synthetic types among the higher
articulates of the Paleeozoic period is only perhaps what might have
been foretold from a study of the more abundant fossils of other
groups of the animal kingdom. But still it is instructive to witness
the general tendency of discovery in paleontology to render this
induction more clearly evident.
The ironstone containing the fossils is compact and grey, and was
formerly wrought for smelting at a locality on the opposite bank
of the river. It contains great quantities of a small, fragile
fossil, which is almost disk-shaped or slightly ovate in outline,
resembling Hstheria. It has been described under the name of
Ancylus? Vinti ;* but it is evidently bivalvular, and belongs either
1 Miinster’s Beitr., vol. v., pl. 13. 2 Dunker and von Meyer, Palion. vol. iv., p. 17.
3 Trans, Tyneside Field-Olub, vol. vi., p. 221.
390 Mackintosh—Railway Geology in Devon.
to the bivalve Crustaceans just named or to some of the Lamelli-
branch mollusca. The Entomostracans, Beyrichia arcuata, Bean, and
Cythere fabulina, Jones and Kirkby, also occur, together with a few
fish remains, a few stray Anthracoptera, and some fragments of plants.
EXPLANATION OF PLATE XVII.—FIGURES 6-8.
Figs. 6 and 7.* Portions of the fore-wing or tegmina of an Orthopterous insect nearly
allied to Blatta or cockroach. From the Coal-measure opposite Claxheugh,
near Sunderland.
,, 8. Part of an Orthopterous insect, apparently the abortive anterior wing of a
species related to the Phasmide. From the same locality as the last,
* The original of Fig. 7 is in the collection of W. M. Wake, of Sunderland.
Ii1.—Raitway Gronoey, No. I.—From Exeter to Newton-BusHELu
AND MorETONHAMPSTEAD.
By D. Macxinrosu, F.G.S.
(PLATE XVIII.)
HE district selected for this article embraces a very unusual
variety of geological phenomena, consisting of different kinds
of recent gravels and Tertiary deposits, Greensand table-lands and
patches, Triassic sandstone and conglomerate, rocks belonging to the
interval between the Trias and uppermost Silurian strata, trap,
and granite.
From Exeter to Starcross the valley of the Exe widens into a
plain, part of which is permanently occupied by the sea, the other
part showing signs of an “unlimited liability to liquidation”
during high tides and floods. On the right hand, at intervals, may
be noticed a terrace of gravel. Near Alphington it is from ten to
twelve feet thick, thinning out hill-wards. It consists of rounded
fragments of carbonaceous grit, trap, Blackdown flints, etc., with
lenticular patches of finer shingle, clay and. sand, the latter some-
times exhibiting oblique lamination. Between Starcross and Daw-
lish the sea-beach is the most interesting phenomenon. During
south-east winds the shingle is there thrown up against the railway
wall to a thickness of many feet in the course of a few hours. In
some places the shingle may be seen arranged in successive terraces
corresponding to different tidal levels. At some height above the
level of the railway, there are several fine sections of a gravel-
covered old ocean-bed, commonly called a “raised beach. ”
From Dawlish to Teignmouth.—The railway here runs under a cliff
of Triassic sandstone and conglomerate. The sea has left stacks and
pillars, and hollowed-out recesses. The “ Parson and Clerk” rock (seen
best on looking northwards from near Teignmouth) is a fine speci-
men of an arched buttress with an adjacent slender column. The cliff,
in places, has given way to gravitation, assisted by rain and frost, so!
as to originate combe-shaped hollows similar to many in neighbour-
ing inland districts. Re-assorted pebble-beds may be traced on the
top of the cliffs, but it is difficult to distinguish them from beds
im situ unless where they fill up denuded hollows, or contain chalk
Geol. Mag. 1867. SED aie SG) IU 6.
SN
Ss AN 8
———__1__
D. Mackintosh, delt., G. R. De Wilde, fecit. Hailes & Co., Imp.
TO ILLUSTRATE MR. MACKINTIOSH’S PAPER ON
RAILWAY GEOLOGY.
ie
or
eval
aot Se v a
PDL naapgel
Mackintosh—Railway Geology in Devon. 301
flints. On the north and south sides of Dawlish Valley, near the sea-
coast, there is a great thickness of gravel, which, at one time, may
have extended continuously across. But to see the most instructive
and easily-accessible sections of flint-gravel requires one to walk from
Dawlish to Teignmouth along the old turnpike road, which cuts
deep into the ridges by which the nearly parallel east and west
valleys are separated. These cuttings expose Triassic sand, sandstone,
and conglomerate, capped with flints mixed with re-assorted Triassic
pebbles. In some places, beneath a layer of flint-gravel, there are
detached flints deeply imbedded in curved, contorted, and oblique
lamin of sand. One section reveals flints and pebbles more or less
stratified beneath re-deposited and finely-laminated Triassic sand (PI.
XVII. Fig. 1, a laminated sand, 6b layers of light-coloured sand, ¢
flints and pebbles, d Trias). Another section shows a mass of sand
enclosing a patch of flint-gravel, and covered with re-arranged Triassic
shingle and flints, the lower parts stratified. It is clearly impossible
to explain the interweaving of flint-gravel with Triassic sand and
shingle displayed in the above sections, without having recourse to
marine currents, possibly laden with icebergs. Rain will not account
for it; and its situation, on or near the tops of ridges, precludes our
referring it to streams or rivers. To the south of the valley which
opens on the coast at the “ Parson and Clerk” promontory, I could see
no trace of flints, nor anywhere between there and Bishopsteignton ;
an important fact showing that the flints are not the mere down-
lettings of a former gravel-covering, co-extensive with the Chalk, all
the softer matter above the Trias having been washed away by rain.+
This absence of flints from considerable spaces seems to indicate a
sweeping denudation by locally-directed or locally-intensified cur-
rents which left flints on certain areas, and cleared them away from
others.
Tittle Haldon.—Kvery geologist who travels by the South Devon
Railway should walk from Dawlish (two miles) or Teignmouth (one
mile and a half) to the top of Little Haldon, which is about 800
feet above the sea-level. On looking north from the high ground
to the north of West Teignmouth church, this hill, with the spur it
sends off towards the east, presents the outline seen in Pl. XVIII.
Fig. 2, in which a is Trias, b Greensand and sandstone, ¢ Flint-gravel.
At d and e no flints could be seen. At f there were two rounded
trap boulders (amygdaloid passing into a kind of porphyry) be-
tween two and three feet in diameter. Between Little Haldon and
Teignmouth cemetery many trap boulders may be seen on the road-
side. I could find no indications in this district of any rocks in situ
between Trias and Greensand. The main hill (Little Haldon) pre-
sents a curved surface when viewed from the south, but in a direction
north and south it is a perfectly level line, which, at a distance,
excites the wonder of the beholder. On the sides of the hill I
examined several pits, in which the gravel was at least ten feet
thick. It consisted of flint and chert fragments more or less rounded,
1 Sir H. de la Beche long ago noticed the absence of flints from large areas lying
between flint-strewn surfaces as a difficulty in the way of the atmospheric theory.
392 Mackintosh—Railway Geology in Devon.
with much-rounded pebbles of quartz, and of a dark, hard rock with
quartz veins, which may be seen in situ on the borders of Dartmoor.
There were likewise pebbles of slate, a coarse kind of sandstone,
etc., but I could see no granite, though it has been found on Great
Haldon (farther north) by Sir H. de la Beche and Mr. Godwin-
Austen. The flints often appeared as if they had been gathered into
groups. In a pit on the east side of the hill the flint gravel was
underlaid by laminated Greensand, containing in its upper part
blocks of chert graduating into more or less ferruginous sandstone.
I failed to see beds of gravel sufficiently distinct to indicate separate
periods of accumulation.
Origin of Flint-gravel, ete-—The north and south contour of the
two Haldons is a horizontal line, which is generally admitted by
geologists to be a sure indication of a sea-bottom; and this line is
roughly on a level with the table-lands of the Blackdowns. That
both were parts of a formerly-continuous ocean-floor, and that the
plains and valleys now separating them were excavated by water, is
likewise generally believed! As regards the Haldons the rounded
stones, some of them transported, which compose part of the gravel,
show that it is not a subaérial accumulation; and Mr. Godwin-
Austen long ago noticed its resemblance to marine shingle. But
this shingle is continued down the slopes on both sides of Little
Haldon, showing that the sea not only formed the level summit line,
but likewise (during a continuance of the same submergence, or
during a subsequent submergence of the land) the surface of the
slopes. That marine denudation extended down the sides of Little
Haldon is also shown by the fact that (excepting where there are
combes) at equal depths below the summit line the surface presents
a succession of north and south horizontal lines to a spectator
situated at distances too near to admit of the summit being seen.
If so, where are we to fix the downward limit of marine denudation ?
The sides of many ridges and valleys in Devon present a series of
longitudinally-straight lines. Transversely they are regular geomet-
rical curves, which cut the more or less upturned edges of the
strata. This is the case, not only with the Trias between Dawlish
and Teignmouth, and between Teignmouth and Bishopsteignton,
but likewise with many limestone undulations near Torquay, and
between Newton-Bushell and Totnes. In most quarries and railway-
cuttings in south-east Devon the unweathered Trias, and especially
the limestone, comes up within two or three inches of the surface.
Some will probably regard this uniform smoothing and rounding off
as the work of grounding and grinding icebergs. Others may lean
to the idea of a great flow of land ice, similar to that now moving
over a great part of Greenland.
From Teignmouth to Newton-Bushell.—The Triassic strata on the
right-hand side of the railway, though not much inclined, show no
conformity to the shape of the lateral valleys which open into the
1 Sir H. de la Beche and Mr. Godwin-Austen both believed that the excavation of
the valleys commenced later than the distribution of the gravel on the ancient Black-
down and Haldon area.
Mackintosh—Railway Geology in Devon. 393
estuary of the Teign, proving that these are valleys of excavation,
and not of depression. Beyond Bishopsteignton the railway cuts
through what has been called Carboniferous slate passing into
limestone. The surface is here covered with gravel containing flints,
which may have come from Little Haldon, or from Milber Down on
the opposite side of the estuary. It would be very interesting to
obtain sections which would corroborate Mr. Godwin-Austen’s state-
ment that a flint gravel extends under the Bovey formation farther
on, as this would prove the gravel to be of pre-Miocene age. A very
remarkable deposit of regularly-stratified flints and sand has lately
been exposed near the summit of Woolborough Hill, south of New-
ton-Bushell, where Greensand is represented on the Ordnance Map.
The beds must originally have been horizontal, but they now dip
eastwards at a very high angle, showing that since their deposition,
considerable changes of surface-configuration, resulting from eleva-
tion or depression, have occurred in this district. The above beds
appear to run under the Decoy clay and lignite, which are a southerly
ae of the Bovey formation, but this may be in appearance
only.
The Bovey Formation..—On leaving Newton station for Bovey-
1 The most recent writers on this formation are Mr. Pengelly, Mr. Key, and Dr.
Heer. The following is a very condensed statement of some of the principal facts
contained in Mr. Pengelly’s paper read before the Royal Society, November, 1861.
The Bovey basin, exclusive of the part south of Newton, is four miles in greatest
breadth, and six in length. In the “Coal-pit”’ (about half-a-mile from Bovey) the
beds dip at 123° towards 8.W., the strike being N.W. and S.E. Jn Mr. Pengelly’s
principal section there were 72 distinct beds of lignite, clay, and sand, including the
“head”? or an unconformable covering, the thickness of which was 73ft. The
upper series of beds (order descending) consisted of clay, sand (one bed of sand
6ft. 8in. thick and thinning out eastwards or along strike); many beds of clay and
lignite, one of the beds of clay containing lenticular patches of sand, most of them
containing fragments of lignite, and one bed of lignite 6ft. 2in. thick. Between the
upper and lower series there was a bed of sand about 11ft. thick, coarse in upper part,
finer towards base, containing patches of clay, and thinning out eastwards. Then
came the lower series of beds containing no sand, but consisting of many alternating
beds of clay and lignite, the former containing fragments of lignite. Towards the
base the beds of lignite were very close to each other, and the lowest 4ft. thick.
Some of the lignite beds consisted of, or contained, “‘ board coal.” Out of 27 lignite
or coal beds only seven were more than lft. 8in. thick. In some places rings of
annual growth of trees were seen pressed into ellipses. The beds are known to be
300 feet deep. A short distance E. of the pit, there is a fault running N.E. and
S.W., which proves a vertical displacement of the beds amounting to at least 100 feet.
The beds N.W. of this fault must have extended 100 feet higher than at present,
making the thickness of the deposit previously to denudation at least 400 feet. The
covering called ‘“‘head,” resting on the denuded edges of the beds beneath, con-
sists of sand and clay, with large and small stones of granite, metamorphic rock,
carbonaceous grit, trap, and flint and chert, the latter increasing in number eastwards.
No stones have been found under the “head.” The Bovey beds must have been
accumulated in a lake; the clay and sand must have come from Dartmoor; and the
stones in the surface-covering must have been brought by a current from the north.—In
a paper by Mr. Key, of Newton, read before the Geological Society in November, 1861,
it is stated that the “‘ Bovey deposit” rises from under high tide level near Newton to
151 feet above mean tide on Knighton Heath. He mentions three parallel beds of clay
on the E. side of the basin, associated with muddy clay, silt, sand, and gravel, dipping
west. The clay beds thin out S. of Newton station, and occur again at the Decoy,
where they dip E., and where several associated seams of lignite, parted by dark clay
and vegetable matter, stand nearly perpendicular. ‘The pipe clay at the Decoy has
394 Mackintosh—Railway Geology in Devon.
Tracey, the geologist enters on controverted ground. There is
perhaps no spot of equal dimensions in Britain on which more has
been written, and less understood, The origin of the Bovey forma-
tion is still the great enigma of Tertiary geology. The railway
sections between Newton and Bovey seldom or ever penetrate
beneath the “head” into the body of the formation, but the coal-
pit can be soon reached from the Bovey station. There the reader
can form his own opinions about the mode of accumulation of the
beds. It will be seen from the foregoing statements that the only
fact supposed to prove their lacustrine origin is the occurrence of
freshwater seeds, which (as nothing in the formation is in situ) may
have been drifted into a saltwater estuary or creek from a freshwater
habitat. The facts and considerations which seem to favour the
marine or, at least, the fluvio-marine origin of the Bovey beds,
partly observed by the author, and partly selected from the papers
above noticed, may be briefly stated as follows:—The supposed
barrier in the area of the present Teign estuary, necessary to dam
up a lake, must have been, at least, 200 feet high (taking the height
of the surface at the coal pit at about 100 feet above the sea, and
allowing a denudation of 100 feet indicated by the fault), and it is
highly probable that the Bovey beds once reached a height requir-
ing a much higher barrier. It is, however, unreasonable to suppose
that the Teign estuary valley was filled up to such a height in or
since middle Tertiary times. The slopes of this valley down to the
water’s edge (excepting where there are small cliffs) are obviously a
continuation of the general contour of the surface of the neighbour-
hood, including the sides of the Bovey basin, and must have been
formed by'a pre-Miocene denudation. As regards the “head,” the
occurrence of boulder-stones (I have seen some on the side of Lever-
ton road four feet in diameter), and other facts, show that it could
not have been accumulated by any motion of water in a tranquil lake.
The highest Pholas-borings near Torquay must have been made when
been worked about 90ft. deep. Traces of clay may be found as far in the direction of
Torquay as the Old Atmospheric Engine House. At the Bovey Pottery (coal-pit) the
beds dip to S.E. about 11lin. in a fathom (an old man who has worked among the beds
nearly 40 years informed the author that about the Pottery they nowhere dip in any
direction but S.W). Mr. Key gives a section taken by the late justly lamented Dr.
Croker, of Bovey, in which some of the beds are represented as very unequal in thick-
ness and of variable dip. Others have their abrupt ends apparently resting on beds
less inclined, while an immense basin denuded out of the beds is filled with ‘head.’
Mr. Key believes that the Bovey deposit, both body and head, originated in the river
Bovey, discharging various kinds of sediment into a deep lake. ‘The river once ran
through the lake from near Bovey to near Newton, and thence, by way of Torr, to
Torbay—the estuary of the Teign having been subsequently excavated.—Dr. Heer
(paper read before Royal Society, November, 1861) states that the dwarf birch found
in the “head” is an arctic plant, and, along with the associated willows, points to a
cold climate. In the body of the deposit the following sub-tropical plants of Lower
Miocene Tertiary age have been classified :—Cinnamon, laurels, fig, palm, tree-ferns,
etc. But the woods that mainly furnished the lignite consisted of a huge sub-tropical
coniferous tree, Sequoia Couttsie, resembling the present Sequoia of California, The
lower lignite beds consist almost entirely of stems of this and other trees, with brownish
black clay. The trees never occur upright, and must have been drifted, the majority
from a distance beyond the shores of the lake in which the beds were accumulated.
The occurrence of seeds of Nymphaea shows that it must have been a freshwater lake,
2
Mackintosh—Railway Geology in Devon. 395
the sea covered the north-west part of the present Bovey plain to a
height of at least 140 feet ; and, as the denudation of the body of the
Bovey formation must have occurred before the deposition of the
“head,” it is probable that this deposition took place under a very
considerable depth of salt water. Both events, the deposition of
the “‘head,” and the perforation of the limestone rocks, may have
occurred during the cold period. Dr. Heer has rendered this certain
so far as the “head” is concerned. The immense mass of clay and
sand composing the body of the formation could not have been carried
from Dartmoor by a river of a size equal to any watershed dependent
on the present configuration of the ground; and the same remark
applies to the timber which supplied the beds of lignite, and which
Dr. Heer admits could not have principally come from the shores of
a lake. The waves of a lake only about two miles in average breadth
could have done little to distribute sand, clay, and heavy timber. The
layers of the Bovey formation are not arranged (even in the same
beds) according to specific gravity, as would have been more or less
the case in the tranquil waters of a lake. The beds of sand thin out
in a way indicating denudation by currents. Thus the thick middle
bed of sand, in thinning out eastwards, in places exhibits an abrupt
termination of its subordinate beds. Fragments of lignite, which
look as if they had been denuded out of older lignite beds by cur-
rents, occur in the clay beds. In the thick bed of sand there are
intercalations of clay and differently coloured sands, which point to
a to-and-fro action, such as is now producing similar phenomena in
tidal zones, and probably at greater depths in the sea. Approximations
to false-bedding occur in the above bed of sand as well as in some
parts of the “head.” Nothing but currents denuding and _ re-
depositing, and at intervals changing their direction, during a long
lapse of time, would seem to offer a sufficient explanation of these and
other phenomena connected with the Bovey formation. On many
coasts, and in bays and estuaries, in recent times, currents have
brought from a distance and deposited immense quantities of pure
sand or clay, sometimes alternating, and’ this irrespective of the
nature of the immediately adjacent rocks. In lakes no such de-
posits, distinct from coast materials, can accumulate much beyond
the delta or sides of traversing rivers; and it is improbable that the
surface of the supposed Bovey lake ever reached the level of the
granite on the west and north, from which the Bovey sands and
clays are believed to have been mainly derived. The great masses
of heavy timber, now compressed into lignite, in the lower part of
the Bovey formation, would seem to imply, as an efficient cause, a
neighbouring forest-area gradually, or paroxysmally, subsiding under
the encroaching influence of oceanic currents.
Old sea-bed—Slate and Igneous Rocks.—That this district has been
at least once submerged to a depth of not less than 140 or 200 feet
below its present level, would appear not only from the Torquay
Pholas-borings, but from the discovery of an extensive bed of boulder-
drift very lately exposed by railway cuttings to the north-west of
Bovey. It may at one time have covered a continuous slope, re-
396 Mackintosh—Railway Geology in Devon.
sembling an old tidal zone, which has been intersected by the sub-
sequent excavation of valleys. The railway cuts through a series of
the remaining ridges and platforms, revealing the same bed at dif-
ferent levels (See Plate XVIII. Fig. 3, a drift, b slate, ¢ railway).
Many of the boulders are more than three feet in diameter.
Most of the stones are much rounded and often polished. The
drift exhibits no order in the arrangement of the stones, which
lie at all angles, and sometimes enclose lenticular patches of sand.
It bears no resemblance to river-shingle, supposing a river could
have distributed so great a quantity of drift over so large an area.
The size of many of the stones, the signs of violence apparent in
the pell-mell heaping together of materials, and the extent of sur-
face covered, render it certain that no tranquil lake could have de-
tached, transported, and accumulated this drift. It seems only
explicable by the action of the sea during a gradual rise of the land.
The stones consist of an extremely hard yellowish-white igneous
rock, a hard and dark-coloured rock, quartz, pebbles with quartz
veins, etc.,—all indirectly local. The first railway-cutting north-
west of Bovey station is through a crumbling shale or slate
(Carboniferous ?) capped by boulder drift. Cutting No. 2 is through
a plateau covered with six feet of drift. The slates underneath have
been shaved off, in some places broken off, and re-arranged. No. 38
reveals a great thickness of drift in regular layers. In No. 4 the
shale, slate, or whatever it may be called, exhibits a whitened or
baked appearance, in which the stratification is often lost. In places
it resembles trap. In No. 5 the rocks are much stained with oxide of
iron, and only thinly covered with drift. Farther on the drift, with
stones 84 feet in diameter, re-appears under a covering of angular
detritus. In No. 6, under a great thickness of slaty detritus, the
drift resembles some of the raised beaches on the Cornish coast. In
some places it has become consolidated. It contains numerous
rounded and polished boulders of yellowish-white igneous rock. In
No. 7 the drift still shows itself, covermg an indescribable kind of
rock, consisting of shale, graduating into the hard dark-coloured
stone, which has largely supplied the boulder drift. Dykes or veins
of a yellowish-white igneous rock (Elvan?) here make their appear-
ance. In No. 8 there is a fine display of the junction between slate
and an erupted mass of yellowish-white igneous rock with dark specks
(Pl. XVII. Fig. 4, a igneous rock, b,b slate). As the ground has
obviously been lowered by a great amount of denudation, the observer
may be cautioned against regarding the right and left hand pro-
jections of the igneous rock as superficial overlaps. In some places
the shale close to the erupted mass has undergone little or no
alteration.”
1 At a lower level, by the side of the railway, a deposit of much finer gravel may
here and there be seen, part, if not all, of which may be river shingle. i
2 This igneous rock I at first took for a fine-grained granite, and on the Geological
Map it seems to come within the granite area. I saw afterwards a stone on the road-
side to the east of the Blackenstone rock, one part of which consisted of this rock
separated by a straight and very distinct line from the other part, which was very
decided granite. In the present unsettled state of petrology, it is perhaps better to
be cautious in applying names.
Mackintosh—Railway Geology in Devon. 397
Cuttings through Granite—Ready-made Boulders.—In the two cuttings
south of Lustleigh station, the rock consists of irregular masses of
rather hard granite apparently imbedded in very soft granite stained
with iron, and more or less laminated (foliated ?). Here and there
angular blocks, or groups of angular blocks, are surrounded by a
matrix of loose-grained granite. In one place_a dyke of trap, or
altered slate, rises up through the granite. In the cuttings north
of Lustleigh station, the granite consists of hard masses of approxi-
mately spheroidal shape, with soft granite intervening (Pl. XVIII.
Fig. 5). The loose texture of the great mass of the granite may be
increased by atmospheric influence ; but as it occurs at considerable
depths from the surface in fresh excavations, it must be partly, if
not mainly, regarded as the original state of the rock. It would,
indeed, be more in accordance with the appearances presented, to
regard this loose and soft material more as a half-formed than a dis-
integrated granite. At intervals the spheroidal masses lie as if they
had been imbedded, though they are really the effect of some process
akin to segregation. They have a hard, well-defined, and permanent
surface. he concentric layers or shells, which are sometimes in con-
tact with these masses, exfoliate only to a certain depth, and appear
to be rather hardened parts of the neighbouring matrix than the
outer structure of the masses themselves, though this may be in
appearance only. The matrix can be easily removed with the end of
an umbrella, leaving a large round boulder. Such boulders, how-
over, must be regarded as distinct from the boulders on the higher
grounds where the granite is hard and jointed, and where the stones
must have been originally cubical. While many of the latter stones
have evidently been transported, those around Lustleigh are princi-
pally in situ. ‘The soft granite, once filling up their interspaces, could
not, however, have been washed away by rain, as they often rest on
ground where rain-water could not have acquired a transporting
power. The surface of the ground between these stones (some of
which are 15 feet in diameter) is generally smooth and not rutted,
and the outline of the knolls (revealed by railway cuttings) con-
sisting of soft granite with included hard masses, frequently presents
a smooth and uniformly-continuous curve-——the obvious result of a
denudation laterally directed, and sufficiently powerful to disregard
the hardness and softness of materials. (See Plate XVIII. Fig. 6).
Apparently re-assorted Granite—On many parts of Dartmoor, not
only fillmg up hollows and covering slopes, but distributed over
level areas, deposits of stratified granitic detritus are not uncommon.
I have seen them on the road-side between the Hountor rocks and
Rippon Tor. But it is sometimes difficult to distinguish between
such deposits and soft granite an situ. At Moreton-Hampstead station
a large section of soft granite presents the appearance of oblique and
curved lamination with imbedded fragments of dark-coloured quartz;
but a more minute inspection will be sufficient to convince the
observer that the granite is im situ, and that whatever may have been
the original arrangement of the crystals, the present apparent lami-
nation is foliation, perhaps rendered more striking by the absorption
398 Mackintosh—Railway Geology in Devon.
of rain-water. Whether the foliation coincides with original lamina-
tion is a question for the petrologist.
“ Boss and Tail,” near Moreton-Hampstead.—This town is sur-
rounded with many projections of granite which throw some light
on the later denudations of the earth’s surface. The Blackenstone
Rock (about 23 miles to the east) is one of the most striking granitic
bosses in Hurope. On account of its elevated position it can be
seen from a distance of many miles round. The north-west side
must be nearly 200 feet high. The most projecting part of this
boss consists of cross-jointed hard granite. It has been rounded
totally irrespective of structure. A close inspection will show that
rain has only roughened its surface. It has been swept clean of
débris all round, excepting a few stones on the north side. On the
north-east side it graduates into a tail which presents a very strikingly
smoothed and rounded appearance. If ice has not been here, there
would seem to be little necessity for supposing it to have been any-
where. There are no distinct striations; but an iceberg, without
stones in its base, would not have striated it, or supposing striations to
have occurred, granite is about the worst rock in the world to have
preserved them. Here the tail is in front (‘‘ upstream ”’), but this is
generally the case with glacial bosses and tails. Plate XVIII. Fig. 7
will give some notion of the appearance presented by the tail, with
the boss fore-shortened, as seen from the north. Nearly all over the
undulating table-land between the Teign valley and Dartmoor, com-
monly so-called, there are rounded, smoothed, and levelled surfaces
which can be best explained by ice-action.
Rock-basins.—A great number of rock-basins may be found within
a few miles of Moreton-Hampstead. Geologists would do well to
visit the Druid’s altar (near the Blackenstone Rock) before it is quite
quarried away—before \its rock-basins are exploded by gunpowder,
and its “ribs of beef” chopped up. The latter term is applied to
six or seven ridges and furrows running down both sides of the
summit of the rock. Though rain is roughening the ridges, it is
certainly not forming the furrows, which are covered with moss. On
this and neighbouring parts of the rock there are many basins. One,
very regular and smooth-sided, is partly filled with grass-covered soil.
On the north side of the rock there is a double basin which slopes
(see Plate XVIII. Fig. 8) towards the brink of a precipice. In other
places there are small deep, round, smooth basins like pot-holes on the
sea-coast, or in the channel of a river. In one of these I observed the
rain-water in a state of gyratory motion; but the round form was
evidently the cause, not the effect, of the whirling of the water. On
Hell Tor (commonly called Heltor Rock) there is a very large basin
(at least 6ft. in diameter by 3ft. deep), one side of which is of a
perfectly semicircular form, evidently hollowed out by a forcible
agency. It is broken down on one side by a rent, so that it can hold
no rain-water. There are many small basins on the top of this tor.
Origin of Rock-basins—Mr. Ormerod, F.G.8., of Chagford, the
principal writer on rock-basins, seems to follow Dr. MacCulloch and
other early geologists, in attributing all rock-basins to atmospheric
Mackintosh—Railway Geology in Devon. 399
action. But from a very particular examination made during stormy
weather, I think they ought to be divided into two kinds—pluvial
and marine. The first would appear to be formed as follows :—A
slight hollow on the upper surface of a rock collects a little rain
water which, agitated by wind, and aided by the fall of fresh drops,
detaches a little fine detritus. A continuance of the process deepens
the hollow until it reaches the lower limit of the agitated water.
The small wind-waves enlarge the cavity laterally, forming a minia-
ture line of cliffs, which (except by mere accident) are destitute of
any curvilinear regularity. In this way shallow flat-bottomed, rough,
and steep-sided rain-pools are formed, but they are distinct (except-
ing when one kind of hollow has been superimposed on another)
from basins with smooth, regular, and perfectly curvilinear sides.
The latter occur chiefly on the inclined surfaces or sloping sides of
rocks, and are often open on one side, so that they can contain little
or no water. These basins are fac-similes of hollows now ground
out by waves wielding stones or sand on sea-coasts, or on the
projecting rocky islets of archipelagos. The tendency of rain-water
is evidently to roughen their bottoms and dilapidate their brims ;
in other words, to ruin instead of to form them. On the Dartmoor
granitic area these basins have often, in spite of rain, retained a
smoothness equal to that of many stone basins chiselled out for
domestic use in the neighbourhood. If the marine theory can be
disproved, their artificial origin is the only explanation left, for they
are generally situated on heights remote from channels of rivers.
General remarks on Tors.—On any intelligible theory of the ele-
vation of the so-called igneous rocks of Dartmoor, the present cannot
be the original outline which their surface presented. The hills and
ridges are at least partly the effect of the denudation of the inter-
vening valleys, and the tors are evidently the remnants of a former
lateral extension of the jointed masses of which they are composed.
Many of the tors exhibit clear indications of their having once been
connected with other tors, and all of them may be regarded as the
unscathed monuments of a stupendous denudation by which the
neighbouring parts were removed. The denudation may have com-
menced in Tertiary if not in earlier times. The rounded forms of the
hills, and many of the rocks (see “Boss and Tail”’), may have been
enhanced, if not caused, by icebergs. But the present shape of most
of the tors of Dartmoor can be best explained by the action of
waves and currents. They generally occupy the summits of emi-
mnences where the sea may not only have surrounded them, but
washed over them and through them, and where it may be:said to
have had them at its mercy. They occupy what may be called the
waterless centres of watersheds. Rain has not space to acquire an
abrading power (except in the case of rain-pools) within their
circumference. What falls innocuously runs off. The grass or
heath comes up to the base of many tors, particularly on one side ;
and as no gradual shading off into parts now undergoing decompo-
sition is generally apparent, there must have been a sudden cessation
of the ‘‘sweeping denudation ;” it must have finished its work
400 Mackintosh—Railway Geology in Devon.
within a given period; the natural edifice must have received its
last touch when Dartmoor last rose above the sea; and, since the
final embrace of the denuding agent, the powers of the air have not
had time to mar the general effect. On one side of some tors the
assailed blocks must have been carried clean away in a manner that
ice will not account for, and which is altogether inexplicable on the
subaérial theory. In the vicinity of other tors we find heavy blocks
of granite out of place, and piled on blocks likewise out of place, on
nearly level ground,—a phenomenon to which a mere wasting, trick-
ling, dribbling agency, such as rain, could never have given rise.
Many cleanly-cut passages through the tors have evidently been left
by a wholesale clearance of blocks, and where these are wanting,
the indentations, inlets, and incipient caves point to the insinuating,
disentangling, and removing agency of breakers. The smaller
crevices are not always, as has been imagined, the effect of enlarge-
ment of fractures by rain, and, therefore, stages in the passage-
forming process, but often the original fractures themselves with
their rain-proof sides minutely corresponding.
_Rock-pillars— Among the tors of Dartmoor there are many rocky
projections, more or less regular, to which this term may be applied.
Bowerman’s Nose, near Manaton, is perhaps the most striking. The
impression it must leave on an unbiassed mind is that a powerful
cause has carried away the blocks by which it was once surrounded.
Nothing seems more obvious than that the denudation must have
been equal to the removal of whole blocks, and not merely of chips
or grains. In the case of this and other rock-pillars, there are no
indications of the parts removed having been softer than the parts
left unscathed. Indeed, the path of denudation appears sometimes
strewn with the very blocks which once composed the massive
structure, of which the pillar is the only part now remaining in situ;
and these blocks are often in positions where they could not have
fallen, and where, therefore, they must have been carried.
In illustration of the above remarks on the rocky projections of
Dartmoor, it may be stated that the Hountor Rocks consist of a series
of cliffs formed by the removal of whole blocks, and roofless caves from
one to three blocks wide, from which whole blocks must have been
abstracted. ‘The two Hey Tors (which may be seen at a distance of
ten miles from the railway at Newton) exhibit similar phenomena,
but they are principally remarkable for the evidence they present
of the denuding agent having come from the south-south-east'—
smoothed the projecting masses up an inclined plane—stripped bare
the sides—and scattered myriads of blocks and fragments towards
the north-north-west along a slightly-inclined surface, the contour of
which, from a distance, presents a perfectly straight line.? How far
1 Since writing the above, I have found that the ingenious author of ‘ Frost and
Fire,” briefly mentions the Hey Tor Rocks as having been denuded by ice float-
ing from the north-east, without referring to the direction of the tails and scattered
wrecks. He likewise notices the ice-ground contour of the Blackenstone Rock, but
leaves its tail out of consideration,
2 These blocks and fragments consist of, at least, two kinds of granite: a reddish
fine-grained variety, and the common coarse-grained variety with large oblong
crystals of felspar.
Miss E. Hodgson—On the Furness Limestone. 401
floating ice or icebergs may have assisted the sea in accomplishing
so stupendous a result, would form an interesting subject for inquiry.
The southern side of the tors has been swept clean. The tail
(directed south-south-east) of the western tor has been smoothed and
rounded. Both tors, especially on the southern side, have likewise
been smoothed and rounded—in many places so independently of the
structural arrangement of the rocks, that Pl. XVIII. Fig. 9 fur-
nishes a correct illustration; Pl. XVII. Fig. 10, represents the Hey
Tors as seen from Ingsdon Hill, looking south-south-west; (a re-
presenting scattered stones).
TV.—Tue Movunpep Limestones or Furnsss.
By Miss E. Hopeson.
T atime when those curious forms often assumed by the upper
beds of limestone rocks are thought worth attention, and are
brought forward by some geologists as evidences of sea-action, it
may not be wholly without interest if I re-introduce a curiously
moulded bed of this rock, occurring near Ulverstone.
In a memoir on the Glacial Drift of Furness (written in 1864,
and published in the last number of the “ Geologist”) I noticed
these stones as having been met with in many places under a thick
covering of drift,—in mining, in railway-cuttings, well-sinking, and
excavations for building-stones, ete.; I did not consider them as
immediately connected with glaciation, but simply noticed them as
examples of the extreme solubility of limestone when remaining
long in contact with moisture.
Not much instruction, however, could at that time be derived from
their accidental appearance at various points, often some miles apart ;
and it is only within the last few months, owing to greatly-extended
quarrying—more methodically carried on, that they have at length
been well seen in situ.
To give some idea of the area over which these moulded stones
extend, it will be necessary to describe the position and surface dis-
tribution of the Carboniferous Limestone in the district of Furness,
or that part of Lancashire which forms the west side of Morecambe
Bay.
This formation constitutes, doubtless, much of the floor of More-
cambe Bay ; and on the Furness side of it flanks the Silurians in a
long band, from one to five miles broad, and about ten in length,
Towards the south, where it is broadest, it is succeeded by the rocks
of the Permian series, and is wholly hidden from view at the south
end of the Furness promontory.
The most elevated or thickest part of this range is Birkrigg
Common, a ridge rising 446 feet above the sea, and rather less than
one mile from the shore. The beds dip shoreward, or south-east, at
about an angle of 9°. They are nowhere scarped into great preci-
pices on the shore line; but when not covered up by beach gravels
on the one hand, or Boulder-clay on the other, present fine tabulated
slopes to the spray of the sea; and, despite its defacing action, as
VOL. IV.—NO, XXXIX, 26
402 Miss E. Hodgson—On the Furness Limestone.
well as that of rain, they still show remnants of glacial planing
and strie, bearmg north-east-by-north, and south-west-by-south.
These latter may not, however, have been very long exposed to
the direct influence of either rain or sea.
There is a good deal of bare rock to the south and south-west of
Birkrige—inferior ridges out-cropping along the strike. Some of
the beds are very rugged and much broken, the blocks having been
apparently shifted en masse and carried off; others display almost
exact counterparts of those on the shore, but with this notable
difference, that there is in the higher rocks a far greater preva-
lence of branched channelling and basin-like hollowing of the stone,
more rounding off of edges, and more vertical column-like fluting.
The western edge of the series skirts the lower Silurian hills in
long reaches, rather difficult to define, and only, indeed, to be con-
jectured even with the aid of borings. It does not appear to thin
out greatly, for at Tarn Close Quarry, one mile to the north-west of
Ulverstone, within a hundred yards of what must be its junction
with the slate, it has a depth of more than sixty feet. Some of the
beds here have been found parted by very thin coal-seams, shales,
and sandstones, containing Syringopora ramulosa and a small species
of Lithodendron.'
The greater part of this limestone tract is hid under a vast cover-
ing of drift,—glacial, fluviatile, and marine.
It is principally along the western edge or junction with the slate
that sinking for iron ore is attempted; and hence it is principally
along the western edge also, beneath a mass of glacial deposits of
varying thickness, that the moulded limestones have been disclosed.
In fact, wherever a limestone surface has been reached, there invari-
ably the upper bed is found to be deeply indented into curious forms.
The accompanying sketch by my sister is a very faithful repre-
sentation of the mouldings as they are shown in the Tarn Close
Quarry. (See figure, p. 403).
This curiously moulded bed is capped by unstratified Boulder-
clay from seven to fifteen feet in thickness, containing striated stones
of all sizes up to boulders thirteen feet in girth ; none of them are lime-
stone. ‘The indentations are all filled with and covered over by a
tenacious clay nearly free from stones, which on being carefully re-
moved brought away a limy film from the mouldings, leaving the
limestone surface rough and pitted. Some of the edgings of the
mouldings are extremely sharp.
The indented blocks represented in the drawing are from three to
five feet long between the fissures, two feet broad from the front to
the next joint, and eighteen inches in depth. The blocks are easily
drawn off, when they disclose similar ones behind. The bed upon
which this moulded limestone immediately rests is divided into four
or five thin separate layers, which are extremely regular and
1 These and the following ill-preserved fossils from the Birkrigg rocks, were
obligingly named by Mr. John Rofe, F.G.8.:—Amplewus coralloides ; Campophyllum
Murchisoni ; Cyathophyllum regium; Cyathophyllum Stutchburyt ; Lithostrotion
junceum ; Zuphrentis, ete.
Miss LE. Hodgson—On the Furness Limestone. 405
uniform around the quarry, and are vertically jointed in the same
regular manner. Below this “rotten rock” (as the quarry-men term
it) the beds supply very good building stone.
The three or four localities where this moulded limestone has been
noticed vary considerably in elevation. The Tarn Close Quarry
(formerly the site of unsuccessful mining operations) is about 270
feet above the sea. The elevation of the limestone in the Lindale
Moor Iron Mines is about 350 feet ; in the railway cutting I believe
it is found between 175 and 200 feet; and in the well-sinking
instance, as nearly as can be ascertained, it would be at an elevation
of 125 feet above the sea. These, but especially the Tarn Close
Quarry, all afford excellent evidence of moulded surfaces under deep
drift ; and they extend over an area of more than three miles.
ZEEE Ze LM
= a |
LEC Fae —— =i
Yippee ae ZS Aff hy ip Ze LON
Ain a oe Mlle WA We
SS aS eS ee —
Tarn CLosE QUARRY IN THE CARBONIFEROUS LimESTONE, NEAR ULVERSTONE.
ae prouldes and indented limestone, originally capped with Boulder-clay 7-15 feet in
thickness
b. “ Rotten Rock” of the Quarry-men.
c. Compact limestone, suitable for Buds ene
Returning to the comparatively driftless ground of the Birkrigg
range, hundreds of these curiously moulded blocks occur, often within
two feet of the surface, and even less: they have been dug out for
many years past for rock-work. They are thinner here than those
figured, and have not such a deep indented profile. The best speci-
mens, the quarry-men say, are those under the deepest cover of drift—
in these the sculpturing is carried quite through the stone, and thus,
what have once been immense unmanageable slabs, are found dis-
solved away into detached and convenient pieces, often presenting
fantastic forms of considerable beauty. They rest upon a bed of
“rotten rock” exactly as in the Tarn Close Quarry, and like those
under the great drifts they are not confined to any particular
elevation.
404 Miss E. Hodgson—On the Furness Limestone.
It is manifestly impossible to claim any distinction for the Birk-
rigg rocks, however curious: they have their true imitations on the
high grounds of Grange, Silverdale, Wharton, Whitbarrow, and east-
ward on the Scars, near Kendal. Indeed, it is needless to multiply
examples, for is not this the natural appearance of the surface of the
Mountain Limestone wherever it is the upper rock of the country
and undisturbed ?
The limestone terraces of the Burren hills in Ireland do not appear
to have suggested the sea as the direct agent to the author of the
“ Student’s Manual,”—the exposed beds are there “cut into blocks
by deep fissures, the uppermost blocks are loose and tottering,—and
are worn into rough knobs and holes by the mechanical and chemical
action of the weather.”?
The late Dr. Woodward, in a letter dated August, 1863, says, “It
has always appeared to me that the drip and splash of rain and rain-
water was the chief agent in honey-combing limestone by virtue of tts
dissolved carbonic acid gas.”
In “ Principles of Geology,”? due weight is given to the power of
carbome acid in dissolving limestone rocks.
Mr. Cameron, ¥'.C.S. (to whom I sent specimens of rocks and clays
from Tarn Close and Birkrigg), points to the same chemical action
for their elucidation. He reminds me that carbonic acid gas is one
of those agents in nature that works slowly, but gradually and surely ;
that it decomposes the hardest rocks, carrying away part of their
constituents; that it combines with potash, soda, lime, magnesia,
etc., water, the necessary medium by which it operates, absorbs its
own bulk, or rather more of it, from the atmosphere, and carries it
into fissures and crevices of the rocks, where it acts as a solvent upon
these substances, forming carbonates and bi-carbonates.
With the Birkrigg, etc., rocks, no doubt rain-water, charged with
carbonic acid, has had a great deal to do.
Mr. Cameron attaches considerable importance to the decaying
vegetable matter of the soil. Liebig states that humus (decayed
woody fibre) is a continual source of carbonic acid,—an atmosphere
of carbonic acid surrounds every particle of decaying humus ;* and,
again, “It is evident that plants, by producing carbonic acid during
their decay, and by means of the acids which exude from their
1 “ Manual of Geology,” by J. Beete Jukes, p. 513.—Since writing the above, it
occurred to me to turn to the memoir by Mr. Jukes on the River Valleys of the
South of Ireland; and I fear the fact will scarcely be believed, that the description
given there of the limestone of the Burren hills, so true to nature as it evidently is,
had hitherto entirely escaped my attention.
2 Prin. of Geol. vol. i. pp. 331, 333, Sir C. Lyell. :
3 Liebig’s Chemistry of Agriculture and Physiology, p. 48. There is palpable evi-
dence of the truth of this in the small angular stones (one cannot call them pebbles
or shingle) which may be found entangled amongst the grass-roots where the sod
is thin. It will be seen that there is a remarkable tendency amongst these to termi-
nate in points, more or less sharp; sometimes in one, awl-like; or in two or more,
often closely resembling fossil teeth of fishes. Below, where these occur, are quanti-
ties of miniature “‘rockery stones” of every form and shape. There could not,
certainly, be a greater proof, I think, of the absence of wave-action than in these
extraordinary examples of limestone débris.
Miss E. Hodgson—On the Furness Limestone. 405
roots in the living state, contribute powerfully to destroy the co-
herence of rocks. Next to the action of air, water, and change of
temperature, plants themselves are the most powerful agents im
effecting the disintegration of rocks.” *
Mr. Cameron thinks that the fine clays found in contact and also
in crevices and pockets may possibly in some cases represent the
argillaceous or insoluble portion of the dissolved rock itself.
The Furness limestones then seem to offer illustrations of three
somewhat different dissolving processes. Firstly, that of atmospheric
disintegration aided by frosts and direct rain-fall, and also by minute
encrusting lichens. (These influences are well shown on many
exposed rock-surfaces of this district.) Secondly, that of rain and
decayed vegetation, as illustrated by rocks with a thin covering of
soil and drift. Thirdly, that of rain-water acting at greater depths
upon limestone rocks deeply covered with drift ; the more easily solu-
ble portions of the limestone being dissolved in every case. Assum-
ing the correctness of this explanation, it seems needless to call in so
remote an agent as the sea, even if it were capable of producing such
an effect. The striated and polished surfaces here and there met with,
which appear to be a few remnants of the Glacial Period, may have
been preserved from honey-combing and disintegration because their
polished and compact surfaces were better able to resist the chemical
forces attacking them, than the naturally pitted and uneven surface
of the rock elsewhere.
It was in reference to the assumed work of Mollusks in rocks that
Dr. Woodward called my attention to the more likely agent of rain-
water; and it has been my regret that I did not earlier perceive the
force and value of his suggestions. ‘In Gloucestershire,” he writes,
“there is a bed of the great Oolite, called ‘Dagham Down Stone,’
because it forms the substratum of a large extent of (formerly) down-
land. This must have originally enveloped a continuous bed of
sponges, or something of the kind, for now the rain eats into it
irregularly, leaving holes such as one could make with the fingers in
dough.”
I have reason to believe that many of the cavities in the Birkrigg
stone may be traced to the former presence of fossils. The matrix
of the bivalve shell is recognized so long as its striz are preserved :
but when these are effaced, the origin of the hollow becomes doubt-
ful. So it may be with the tubular cavities.
At the same time it must be admitted that surface inequalities and
honey-combing, if not, indeed, every other form of disintegration, are
mainly due to the texture of the rock itself, inducing wnequal
weathering, independently of any fossils.
With regard to those minute punctures, sometimes accompanying
a lichen encrustation, and sometimes observed apart, it is probable
that the latter, as well as the former, owe their presence to the ~
saucers, or fruit receptacles of these plants. We have it on the autho-
' Liebig’s Chemistry of Agriculture and Physiology, p. 139.
2 See Mr. George Maw’s papers in the GrotocrcaL Magazine, 1866, vol. il. p.
200; 1866, vol. iii. p. 253; and 1867, vol. iv. pp. 241 and 299.—Epir.
406 Eruptive Origin of Granite and Serpentine in Asia Minor.
rity of Dr. (Sir J. E.) Smith that, in one species of lichen, L.
exanthematicus, found on limestone rocks in Yorkshire and elsewhere,
the saucers, when old, leave a cavity inthe stone. Linn. Trans. i. p. 81.
Withering’s Arrangement of British Plants, vol. iv. p. 19.
ING TIC HS) (Of | Men VM@ ES.
I.—Eruptrive ORIGIN oF GRANITE AND SERPENTINE IN Asta Mrnor.
N the first volume of his ‘Geology of Asia Minor” (1867), M. de
Tchihatchef records his observations on the eruptive rocks of
that country. He advocates the igneous origin of granite, and as
some discussion has arisen on this subject in recent numbers of the
Gerotocicat Macazine, a notice of M. de Tchihatchef’s opinions
may be of interest.
Under the collective term “Hruptive Rocks” the author ranges
the following rocks, occurring in Asia Minor, which he considers to
be of igneous origin :—Dolerite, Basalt, Melaphyre, Pyroxene, Por-
phyry, Gneiss, Granite, Granulite, Syenite, and Serpentine.
While advocating (with M. Naumann) the igneous origin of Gneiss,
Granite, and Syenite, the author has had particularly in view these
rocks as they are developed in Asia Minor, without wishing to deny
the possibility of their different (metamorphic) origin in other parts
of the globe. He further states that, although the metamorphic
theory has received a support in the discovery by M. Sismonda of
an equisetum in an erratic block of gneiss in the Alps, yet before
generalizing on this phenomenon we must assure ourselves whether
the gneiss of other countries furnishes arguments as conclusive in
favour of this interpretation. But in Asia Minor, not only has
nothing similar been discovered, but the gneiss is there found so
intimately associated with the granite that one cannot but assign to
the two rocks a common origin, and as the granite presents under
more than one relation the character of an eruptive rock, he is of
opinion that we must not separate one from the other until proof to
the contrary is obtained.
The serpentinous rocks occur as agents of upheaval in enormous
masses, intimately associated with the sedimentary deposits (Cre-
taceous and Eocene), and often intercalated among them. The
eruptive nature of these serpentines is indicated by their action on
the deposits with which they are found in contact, by the exterior
aspect of the rocks themselves, as well as by the manner in which
they are disposed.—H. B. W.
Il—Tue Keurer Frora or Norta Tyroz. By Professor Ad.
PICHLER.
[Proceed. Imp. Geol. Inst. Vienna, February 19, 1867.]
HE vegetable remains are imbedded in a sandstone, which differs
in no respect from the Keuper sandstone of Franconia. It
belongs to the “Upper Cardita-strata,” and is associated with argil-
The Gasteropods of the Tertiary Deposits of Portugal. 407
laceous shales and marls, containing numerous remains of Mollusca
(Ostrea montis-caprilis, etc.). The most abundant species of plants
are—Pecopteris Steinmiillert, Heer ; Hquisetites arenaceus, Schenk ;
Calamites arenaceus, Jaeg; and Péierophyllum Jaegeri. The more
locally-occurring species are Pterophyllum longifolium, P. Haidingert
(fine specimens with leaflets occasionally one and a half inches in
breadth), and a species of Pterophyllum, with leaflets half-an-inch in
breadth and very long, perhaps P. Giimbeli, Stur.—-Count M.
TIl.—Zone or ANMONITES TRANSVERSARIUS.—Dr. Waagen has
edited, and communicated to the Imperial Geological Institute of
Vienna (Meeting, Jan. 5, 1867), a paper of the late Dr. Oppel, concern-
ing the Upper Jurassic Zone, characterized by the presence of Am-
monites transversarius, limited above by the zone of Terebratula im-
pressa, and below by the zone of Ammonites cordatus. The zone in
question is to be traced from south-west Poland through the Car-
pathians, Moravia, Bavaria, the Schwibische Alps, the Swiss Jura,
the Alps, France, Spain, as far as Algeria. The number of fossil
species known to occur in it amount to 217; among them are mi-
croscopic remains of Crustacea and Radiata, and many new species
of Foraminifera.
TV.—Mammatian Rematns rrom Huncary.—M. de Hantken has
recorded the following mammalian remains from a Post-Pliocene
deposit at Finfkirchen, in Hungary :—Ursus speleus, many frag-
ments of lower jaws, loose teeth, and vertebre ; Hyena spelea, Goldf.,
a fragment of a jaw belonging to a young animal, with the first
teeth and protruding canines; Hquus fossilis, Cuv., a fragment of
a lower jaw with a tooth ; Bos priscus, Boj., a second collar vertebra;
Rhinoceros tichorhinus, Cuy., a single tooth.— Proceed. Imp. Geol. Inst.,
Vienna, Dec. 18, 1866.
V.—TuEe GasTEROPoDS oF THE TERTIARY Deposits OF PORTUGAL.
By Perera Da Costa.
[Gasteropodes dos depositos Terciarios de Portugal, por Pereira Da Costa, com a versao
Franceza por M. Dalhunty. 1o. Caderno, 4to. Lisbon, 1866.]
HE pages of this work are divided into two columns, one con-
taining the original Portuguese of Setior Da Costa, the other a
French Translation by M. Dalhunty, which will be very useful to
those unacquainted with the Portuguese language. This first part
contains 116 pages of letter-press and 15 excellent lithographic plates.
The author has followed Lamarck’s classification in his descrip-
tion of the fossils, and explaims that it is not through want of
appreciating the great amelioration since introduced into the methodic
distribution of the Mollusca, but on account of the great convenience
in modelling the work on that of M. Hornes, descriptive of the fossil
Gasteropods of the Vienna basin, which being a deposit very similar
to that in Portugal, contains the greater part of the species met with
in Portugal.
408 Reviews—Santorin and the Kaimeni Islands.
The author also acknowledges the great assistance he has received
from the works of M. Deshayes, and mentions the paper by the late
Mr. Smith, of Jordan Hill, as the only work hitherto published on
the Tertiary fossils of Portugal.
The author intends giving a summary of his results in the last
part of the work, when all the species will have been described.
RAVE wWws.
I.—Sanrorin, THE Katment Isnanps. From observations by K. V.
Fritscu, W. Reiss, and A. Sruspen. (Translated from the
German.) London, 1867. ‘Triibner and Co. Folio. pp. 8.
3 Plates.
CH interest was excited during the early part of the past year
by the announcements received in this country of repeated
igneous outbursts having taken place in the Kaimeni Islands, a group
of small volcanic islands situated in the Gulf of Santorin, formed bya
large island of that name in the Greek Archipelago. From Greece,
Germany, France, and England numerous scientific investigators re-
paired to study the nature of its phenomena. We have already
(GrotocicaL Macazinz, 1866, Vol. III. pp. 222 and 263) given
some account of these interesting observations and their bearing
upon volcanic phenomena elsewhere. The authors of the present
work furnish not merely an account of the changes produced by
volcanic action in these islands, but, by means of maps and photo-
graphs from carefully executed relievo models of the islands them-
selves, they have laboured—and we think successfully—to convey
to the mind a picture of the theatre of these disturbances and the
changes produced both upon the island and the surrounding sea-bed.
These island-volcanoes offer some interesting points of comparison
with other volcanic areas. They appear also to confirm two important
points in connexion with volcanic action. Firstly, that the volcanic
cones of the Kaimeni islands, though differmg in other respects,
coincide completely with the cones of eruption of other volcanoes,
and afford no support to the elevation hypothesis ; secondly, here, too,
as in many other localities, the craters already existing were not con-
cerned in the later eruptions, the voleanic agencies mostly finding it
easier to force a new passage for the materials thrown out, than to
reopen the older ones.
Besides the three plates which accompany the description, the
authors announce that four other explanatory maps and views of the
Kaimeni islands may be obtained from Messrs. Triibner and Co. as a
separate supplement to their work, giving the configuration of the
island before the eruption and also on the 30th May, 1866, with the
islands of George I. and Aphroessa in active eruption. This plate
gives the best idea of the relation between the supra and sub-marine
parts of the islands, They are greatly to be recommended for the
use of geologists.
Reviews—Monographs of the Paleontographical Society. 409
IJ.—Monograrus PUBLISHED BY THE PALMONTOGRAPHICAL SOCIETY.
Voli xx. > 186i.
iE the Grotocican Magazine for March, 1867, p. 122, we
~recorded the issue (in December, 1866), of the 19th volume
published by this Society, being that due to its members for 1865.
By the energy and zeal of the Rev. T. Wiltshire, M.A., F'.G.S., the
_ Honorary Secretary, another fasciculus has just been issued (June,
1867), being the volume for 1866. We learn that the volume for
1867 is in the press, and will be ready by October or November.
Vol. XX. contains the following Monographs:—I. Part IV.
No. 1. Of the British Fossil Corals (2nd Series), by P. Martin
Duncan, M.B., Lond., F.G.S.—Il. Part IV. Of British Trilobites, by
J. W. Salter, A.L.S., F.G.S.—UI. Part VI. No. 2. Of British
Fossil Brachiopoda, by Thomas Davidson, F.R.S., F.G.S.—IV. Part
III. Of the British Belemnitidee by Professor John Phillips, M.A.,
LL.D., D.C.L., ete. ete.
I. Dr. Duncan gives us an account of the Liassic corals found
in the zones of Ammonites planorbis, and A. angulatus; and belonging
to the following genera: —1. Monitlivaltia ; 2. Rhabdophyllia; 3.
Thecosmilia ; 4. Oppelosmilia ; gen. nov. 5. Isastrea; 6. Astroce-
nia; 7. Cyathocena; gen. nov. 8. Elysastrea; 9. Septastrea; 10.
Latimeandra. In all 10 genera and 48 species. These are illus-
trated by eleven tinted and black-background plates, well executed
by Mr. G. R. de Wilde. The importance of Dr. Duncan’s Mono-
graph may be readily seen when it is stated that only one good
species of Coral, the Trochocyathus Moorei, Kd. and H., had before
this been determined from the British Lias.
Il. Mr. Salter contributes six plates, one of Ogygia and five of
Illenus. He gives an account of the new genus Barrandia longifrons
from the pen of the late H. Wyatt-Edgell, Esq., and describes 16
species of Illenus, 2 of Illenopsis, 2 of Ogygia, and begins the
family of the Bronteide. We hope and trust that the health and
leisure, about which Mr. Salter seems so doubtful, may be granted
him to complete this grand work, a bird’s-eye view of which he
gives us in his “ Notice to Correspondents.”
Ill. The untiring mdustry and genius of Mr. Davidson have
enabled him to add another charmingly-illustrated part to his mono-
graph of Silurian Brachiopoda, The single-minded devotion of
Mr. Davidson’s attachment for the ‘‘ Lamp-shells,” is a sermon to
all aspirants for Paleontological honours; it says plainly, “Don’t
have too many irons in the fire.” The writer remembers hearing
the late Dr. Falconer observe to a young Naturalist, “‘ Never mind,
my young friend, how narrow the groove you run in, only take care
to stick to it.”
Mr. Davidson’s part is illustrated by ten well-filled plates, illus-
trating Meristella, Athyris, Retzia, Atrypa, Pentamerus, Stricklandinia,
Rhynchonella, and Merista or Camarium.
IV. Professor Phillips continues his history of the British Belem-
nitide, and adds thirteen more plates, well drawn, and printed on a
410 Reviews— Thomas's Prize Essay.
tinted ground, in Paris. Certainly they do these things, in some
instances, better abroad. Professor Phillips gives figures and
descriptions of 32 species of Liassic Belemnites, of which 16 are new
to science.
IiJ.—Prizz Essay vpon tHe ENcRoACHMENT OF THE SEA BETWEEN
THE River Merrsry anp THE BristoL CHannen. By J. HE.
THomas. S8vo. pp. 24. London, 1867.
HIS pamphlet gives a short account of some of the changes of
our western coast, in great part derived from published works,
which the author has diligently searched ; but in part also from local
traditions and from personal knowledge of the district. An essay of
this sort, which refers to notices that have appeared at various times
and in various ways, is very useful, as collecting together information
on one subject which before was scattered about in many publica-
tions. It is to be hoped that the author will be able to extend his
researches, and to treat of the changes of the western coast in the
detailed way that Mr. Redman has done with the south-east of Eng-
land in his two papers published in the Proceedings of the Institute
of Civil Engineers.
It would have been better if there were proper references to the
authorities quoted : in some cases there are none at all, the quotations
being simply given as by Dr. Hume, Mr. Boult, etc.; im another
case we are told that the information has been got from page 70 of
the Journal of the Geological Society, but as that interesting work
is now in its 22nd volume it would hardly be a labour of love to
hunt up the reference. From an unfortunate misprint that occurs
many times we may infer either that the author writes a very bad
or a very good hand—in the former case, misleading the printer ; or,
in the latter, making him careless: it is the use of the word track
(of alluvium, etc.) instead of tract.
At page 11 it is remarked that the “the chlorite and mica-schists
have been more able to withstand the dashing of the waves than the
limestone and other rocks ;” but it may be questioned whether the
dashing of the waves alone can do much harm to any hard rock, and
one is inclined rather to think that the greater endurance may be
owing to something in the composition structure or condition of
the rocks by which they suffer less from those splitting and dis-
solving subaérial actions that are mostly the cause of the fall of cliffs.
Mr. Thomas is a Civil Engineer, and, in the course of his pro-
fessional work, it may be in his power to do good service to geology
by such researches as that now noticed, which it is to be hoped is an
earnest of others.
IV.—Tae Amuerroan Naturauist: A Popunar Intustratrep Macazine
or Naturat History. Hssex Institute, Salem, Mass., U.S.
London: Triibner and Co. Nos. 1-5, March—July, 1867.
E look with natural interest upon all attempts of our trans-
atlantic cousins at rendering Natural History studies popu-
Reviews—The American Naturalist. 41]
lar. It is undoubtedly the great difficulty and at the same time
the great demand of the age. Toa people like the American nation,
at once so enterprising and possessing such boundless resources, all
things seem possible, and we see no reason why they should not
achieve even this critical object. Good illustrations and cleverly-
written articles are necessary for the success of such a work ; of both
these there is a fair average, the recent Natural History articles being,
as a whole, better than the Geological ones.
We should be-unjust, however, to Mr. W. T. Brigham did we
omit to call attention to his article on a visit to the Volcano of
Kilauea, Hawaii Islands. His description of a night-display of this
volcano which he witnessed is very graphic (see No. 1, p. 19) :—
“As it grew dark we were very tired, having travelled since six
o'clock in the morning; and hoping to wake up in the night when
the fires would be more brilliant, we rolled ourselves up in our
blankets, and, with our guides near by, went to sleep a few rods from
the crater.
“ At nine o’clock I waked, and as the night air was quite cold,
moved to the very edge of the crater to warm myself, and to enjoy
the magnificent fireworks. The moon was up and almost full, but
her light was dull beside the fires of Pélé. Finding the place quite
comfortable, I picked out a soft rock for a pillow, and went to sleep
again. At twelve I awaked with a start, and found myself in a
shower of fiery drops, some of which were burning my blanket. I
shook myself and jumped back, looking at my watch to note the
time, and then stood gazing at the strange scene for some time before
I thought of my companions. The whole surface of the lake had
risen several feet, and was violently boiling and dashing against
the banks, throwing the white-hot spray some sixty feet over the
upper banks, causing the providential rain that awakened me to see
this grand display. There was no thundering or bellowing, only the
splash of the waves as they fell back, or the rattling of the cooled
drops on the upper banks. The light was so intense as to be almost
painful, as the crust had wholly melted, and brilliant fountains of fire
covered the surface.
«When I could think of anything else I called the others, but only
succeeded in awakening the guides, and just then a drop of lava
came plump into a greasy newspaper we brought our supper in, and
it blazed up suddenly to the dismay of our guides, who, thinking
that the voleano had broken out at our feet, at once fled to a safe
distance. Failing to arouse them with my voice, I threw several
handfuls of gravel at the sleepers, but without effect, and I had to
climb down—almost blinded by gazing at the fire—and shake them
roughly. When they at last reached the edge the action had greatly
diminished, and in a few minutes more the dark crust covered the
central portion, extending rapidly to the sides; and after watching
the last crack close, we all went to sleep again. I was glad to see
such distinct flames, as their existance has been denied in volcanoes.
They were bluish green, and shot up in tongues or wide sheets
a foot long.”
412 Reviews—Colonel Greenwood’s Rain and Rivers,
V.—Rain anp Rivers; or, Hurron anp Prayratr acarnst LyELh
AND ALL Comers. By CotonrL GREENWoop. Second Edition.
London: Longmans, 1866.
W* scarcely know what to say of this extraordinary book. That
it contains many happy theoretical hits cannot be denied,
and though the author’s propensity for humourous digressions con-
tinually disturbs the grave attention of the reader, some portions
are well reasoned and clearly expressed. One of his great objects
seems to be to attack Sir Charles Lyell, Professor Sedgwick,
and other great founders of the science of geology ; and while he
accuses Humboldt of concealing the laws of Nature “behind the
double veil of Greek and Latin,” he scarcely writes a page without
introducing a Latin sentence or quotation. Still he must be credited
with the merit of having been the first, of late years, to give to the
world (in the “ Tree-Lifter,” in 1853, and “Rain and Rivers,” 1857,)
a clear exposition of the subaérial theory of denudation. Professor
Jukes acknowledges this in his “School Manual of Geology ;”
and it would only be an act of justice if other subaérialists were
to make more frequent reference to the author. It would likewise
be well if they rendered their speculations more consistent by
imitating Colonel Greenwood in laying the main stress on rain and
not on rivers, for it is obvious that if rains cannot act effectively
in a state of general dispersion so as to produce the gently-sloping
declivities which characterize the majority of hills and valleys,
torrents and rivers which (as the Colonel admits) act on lines
only, could not have given rise to the general form of the ground.
As many who have not read “ Rain and Rivers” may like to know
how far its author has forestalled the more recent advocates of
pluwialism, we shall give a number of quotations from his work :—
““No marine current could make a single channel sloping from a
height to the sea; still less the myriads on myriads of dry upper
valleys which ramify in all directions, from all river valleys,
through and to all sides of the tops of all elevations, whether high
or low.” ‘Soil is rotted subsoil,” and “is in constant formation
over the entire surface of the earth..... Rain produces a denudation
of an enormous breadth of hill-side... .. Rain may be said to
form hills as well as valleys...... Valleys exist only in the disso-
lution of hills. .... A stream running through ridges, large or
small, is the simple consequence of the differing hardness of the
ground through which it runs. In all cases a stream cuts for itself
a narrow channel, the depth of which is determined by its hardest
Parts eve. But the wash of rain digs down where the ground is
soft and leaves hills or ridges where it is hard. And as a stream
cuts through a hard stratum, say the North or South Downs, the
wash of rain is scooping out two lateral valleys behind it, that is a
valley behind each side of the gorge and ridge, as in the Weald clay.
5 eRe The débris of these valleys is carried off by the lowering bed
of the river. A ridge is then developed, and the river runs through
a gorge in the ridge...... Directly as the softness, is the width.
Reviews—Colonel Greenwood’s Rain and Rivers. 413
Above each hard gorge will invariably be a comparatively wide
horizontal valley...... Rivers have the power to cut narrow chan-
nels or ravines, but they have very little power of widening these.
Disintegration and the wash of rain widen these ravines into broad
valleys. While this is going on, rivers convey to the sea what rain
brings to them,....rain is constantly shoving the whole surface
of the earth down towards the sea...... No drop of rain runs an
inch on the surface of the earth without, as far as it goes, setting
some soil forward on its road to the sea, and it wont run back again.
No return tickets are given. It will wait there, and go on by the
nex-t-rain...... Neither wind nor water, under any circumstances,
ever travels empty-handed..... In comparison to the broad waste
from the wash of rain, the waste by the direct action of rivers may
be reckoned as nothing, .. . . rivers are mere labourers or accessories
mo tWevattalts «)... <).-- This universal portage of soil by rain... . may
also be seen, oculus fidelibus, whenever a fence runs horizontally
along the side of a hill. A natural terrace is then formed, .... the
good soil which was on its way to the valley is arrested..... In
France I have seen deep terraces result from very narrow strips left
uncultivated to decide fields or properties.”' In chapter xiv. the
author advocates the theory that man may have existed during the
Silurian period, and asserts that “myriads of species of megathe-
riums, dinotheriums, anoplotheriums, or anyotherthervums (sic), may
have existed before the Silurian or primary and metamorphic period,
without a vestige of their fossil remains being found in these
strata.” (!) One of the best chapters in the book is on “The
Travelling of Sea-beach.”
VI.—OUR SCIENTIFIC JOURNALS.
1. THe QuARTERLY JOURNAL OF THE GEOLOGICAL Soctety or Lon-
pon for August, 1867, No. 91, opens with Mr. Ralph Tate’s paper
“Qn some Secondary Fossils from South Africa,” a region whose
geology and paleontology has several times before occupied the
pages of both the Transactions and the Journal of this Society.
The fossils described are fourteen species of plants, thirty-nine
mollusca, two corals, three serpule, and one cidaris; illustrated by
two double and three single octavo plates. The remains are, unfor-
tunately, very fragmentary ; so much so, indeed, in some instances as
to render their accurate determination a matter open to grave doubt.
Cidaris pustulifera (Plate viii., fig. 9); Trigonia Goldfussi (Plate
vii., fig. 6), and Hamites Africanus (Plate vii., fig. 5,°) are instances
of species founded on very slender evidence. Nevertheless, South
African geologists may thank Mr. Tate for the work he has accom-
plished, and we hope they will try to send better specimens home
next time for description.
1 See a defence of this theory by G. Poulett Scrope, Esq., in Gzonocrcan
Magazine for July, 1866.
2 In the Explanation to Plate vii. p. 174, the names of figs. 4 and 5 are transposed,
and in that of Plate viii. fig. 9 it is omitted altogether.
414 Reviews— Our Scientific Journals.
Mr. J. W. Judd’s paper, “On the strata which form the base of the
Lincolnshire Wolds,” deserves a special notice, which we propose to
give in a future number. Its author, evidently a capital field-
observer, has met with his proper recognition, being one of the few
successful candidates lately appointed to the field-staff of the Geolo-
gical Survey of Great Britain.
Mr. Boyd Dawkins has more to say about British Fossil Oxen ;
this chapter treats of Bos longifrons, which the author considers to be
a comparatively modern type and to be the ancestor of our small High-
land and Welsh cattle. Mr. Dawkins has also another paper, “ On
Rhinoceros leptorhinus of Owen,” which he states to be synonymous
with the Rhinoceros hemitechus of Falconer, but not by any means
the same thing as the Rhinoceros leptorhinus, of Cuvier. Can a
specific name given by one author be transferred to another, Mr.
Boyd Dawkins ?
Sir William E. Logan, and Drs. J. W. Dawson and W. B. Car-
penter have more to say about new specimens of Hozodén, of which
they give illustrations in two well-executed plates.
Mr. H. W. Bristow makes out a strong case against the retention
of the beds named by Mr. EH. B. Tawney (Quart. Journ. Geol. Soc.,
Vol. xxii., p. 69), “Sutton series,” and “Southerndown series” as
composing a formation separate and apart from the Lias proper; and
he shows (1) that there are not two series of beds, but only one; (2)
that the paleontological evidence proves this group of strata to be
true Lias from top to bottom. He considers the term Infra-lias to
be misleading, and recommends Sir Henry De la Beche’s old name
“Tias Conglomerate” as distinctive and unobjectionable.
The Rey. P. B. Brodie contributes two papers—(1) ‘On the
Purbeck Beds at Brill, Buckinghamshire, etc.;”” (2) “On the drift
in part of Warwickshire, and the evidence of Glacial action which
it affords.” ;
The two following papers appear only as abstracts:—(1) Mr.
Charles Moore, “On the Abnormal conditions of Secondary
Deposits when connected with the Somersetshire and South Wales
Coal-basins, ete.,” and (2) Mr. R. Etheridge, “On the Physical
Structure of North Devon, and the Paleontological value of
Devonian Fossils,” they will form, we understand, an extra
number, to be issued at a later date.
A third paper, “On Subaérial Denudation, and on Cliffs and
Escarpments of the Chalk and the Lower Tertiary Beds,’ By
William Whitaker, B.A. (Lond.), F.G.S., of the Geological Survey of
England, a brief abstract of which is only given (p. 265 Quart.
Journ.), will appear in full in the October and November Numbers
of the Gronocican MaGazine.
2. Tan QuartERiy Journat oF Science, No. XV., for July, con-
tains, among others, an article upon Mr. J. Beete Jukes and the Geolo-
gical Society, being a consideration of Mr. Jukes’ recently-published
pamphlet, entitled “ Additional Notes on the Grouping of the Rocks
of North Devon and West Somerset, with a map and section ;”
Reviews—Our Scientific Journals. 415
prefaced by a statement of the reasons which compelled the author
to print and circulate this paper at his own cost among the Fellows
of the Geological Society of London. Space will not permit us to
enter into a prolonged account of Mr. Jukes’s pamphlet here, but
those who care to learn the whole matter, will find it very fairly
argued in the pages of the July Quarterly Journal of Science. We
give the writer’s concluding remarks :—“‘ After a careful examination
of the evidence, we are unable to come to any other conclusions than
the following :—(1) That Mr. Jukes, forgetting the Society’s rules,
has felt agerieved at the refusal to publish in full a paper whose fate
he would doubtless have predicted, had he remembered the Society’s
regulations ; and (2) that he has precipitately written and printed an
attack on the Council of the Society, without first ascertaining that
his recollection of the Society’s rules was sufficiently exact—a course
which can only be compared to rushing into a lawsuit without legal
advice, on the strength of vague impression, and with no real know-
ledge of facts.”
3. THE Popunar ScrencE Review (No. 23) for April contains,
among other interesting original articles, one by Dr. J. D. Hooker,
F.R.S., “On the Struggle for Existence amongst Plants.” In it the
writer shows that there is great truth in the saying (attributed to
Dean Herbert, of Manchester), that «Plants do not grow where they
like best, but where other plants will let them,” and that circum-
stances of climate and soil are not omnipotent in regulating the
distribution of vegetable life. The writer gives numerous instances
of the way in which one class of plants affect the progeny of another
class ; grasses and herbs, for example, smothering the seedlings of
large and prolific trees. Dr. Hooker also cites some of the most
remarkable changes which have been produced upon the floras of
new countries wherever Huropean emigration has introduced foreign
plants, particularly in the spread of many of our commonest wild
plants, and field and garden weeds. No instance can well be found
more interesting than the change effected in New Zealand since first
visited by Captain Cook, both as regards plants and animals. The
domestic pig has run wild, and multiplied to such an extent on the
eastern side of the island that parties employed for their destruction
have been known to shoot as many as 22,000 on a single sheep-run
without any apparent diminution in their numbers. The Norwegian
rat, the Kuropean mouse, and other old-world pests have found their
way out there, and actually dispossessed the native species. The
Maoris, who are keen observers, have this saying, “As the white
man’s rat has driven away the native rat, as the Huropean fly drives
away our own, and the clover kills our fern, so will the Maoris
disappear before the white man himself.”
There is also an article on the Flint Flakes of Devon and Corn-
wall, by Spence Bate, Esq., F.R.S., which is well deserving the
attention of Quaternary Geologists.
The July number (24) has a contribution by Mr. W. Carruthers,
F.LS., On the Botany of a Coal-mine.” It is very gratifying to
416 Renews—Our Scientific Journals.
find that, after a period of so many years, we have again a good
paleobotanist actively at work in this country—one who, from his
connection with the Botanical Department in the British Museum
(so rich in memorials of the late Robert Brown, its former keeper),
may naturally be expected to excel in this branch of science.
The pages of the Grorcercan Magazine contain many valuable
contributions to fossil botany from Mr. Carruthers’ pen. The article
in the “ Popular Science Review” should be read by all who wish
to obtain a good notion about the origin of coal.
4, Tue InreLLectuan OBsERveR maintains its character admirably,
having within its pages a goodly store of information on things in
general, and the heavenly bodies in particular. The very remarkable
change first observed by Schmidtin the lunar crater of “Linné,” situated
in the plain of the Mare Serenitatis (noticed in the “Intellectual
Observer” in January last, and also in many subsquent numbers) sup-
posed to be the result of a volcanic eruption, appears (from the
August number) still to rest upon very slender evidence. There is
great truth in the concluding remarks of M. Elie de Beaumont,
“that if observers, placed in the moon, viewed Vesuvius or Etna
before and after an eruption, they would only notice very slight
changes. A great eruption, even of Vesuvius, would produce no
other effect than to diminish slightly the depth of the semicircular
trench of the Atrio del Cavallo and to change its colour. Seen
from the moon, such an alteration would appear problematical, and
give rise to discussions among observers. A single change, how-
ever slight, would show that geological life exists in the interior of
the moon, as well as of our earth.
The May and June numbers contain an account of the structure
and systematic position of Graptolites, by Mr. W. Carruthers, F.L.S.
(with two excellent plates). The author, after giving their history,
structure, and classification, concludes by a consideration of their
affinities to living forms, and gives good reasons for placing them
among the Hydrozoa, although a somewhat abnormal form of that
class. We should notice two other geological articles which appear
in the August number, one by Mr. Bernard H. Woodward (eldest
son of the late Dr. 8. P. Woodward), ‘‘On the Geology and Ferns of
Glen Clova;” the other “On the Origin of the Cheddar Cliffs,” by
D. Mackintosh, Hsq., F.G.S. The latter gentleman’s name is well
known as a frequent contributor to the pages of the GmonogicaL
MaGazine.
REPORTS AND PROCHEHDIN GS:
———>_
Gzotocican Sociuty or Lonpon.—June 19, 1867.—Warington
W. Smyth, Esq., M.A., F.R.S., President, in the chair. The follow-
ing communications were read :—‘“ On Cyclocyathus, a new genus of
the Cyathophyllidea, with remarks on the genus Aulophyllum.” By
P. Martin Duncan, M.B., Sec.G.8., and James Thomson, Esq.
Geological Society of London. 417
A careful examination of a large series of sections and weathered
specimens of Corals from near the base of the Carboniferous series
at Lesmahago, etc., which have hitherto been referred to the genus
Aulophyllum, E. and H., has convinced the authors that A. fungites,
and A. Bowerbanki must be referred to a new genus, which they
propose to name Cyclocyathus. It differs from Aulophyllum in having
a more or less essential columella of a very complicated structure,
while that genus was described by its authors as devoid of any such
structure. One form in the series of specimens examined by Dr.
Duncan and Mr. Thomson exhibited no columella, and the space
which would otherwise have been occupied by it was covered in by
successive tabulz ; they therefore referred it to Aulophyllum, under
the name of A. Edwards.
2. “On the discovery of a new Pulmonate Mollusk (Conulus
priscus, P. P. Carpenter) in the Coal-formation of Nova Scotia.”
By J. W. Dawson, LL.D., F.R.S., F.G.S.
Some crushed specimens of the little shell described in this paper
were found in a bed of clay, associated with numerous individuals
of Pupa vetusta, between coals No. 37 and No. 88 of the Joggins
section, during a search undertaken for the purpose of discovering,
if possible, traces of land-animals in addition to the Pupa already
known. On submitting these specimens to Dr. P. P. Carpenter, they
were referred by him to the group Conulus,—a sub-genus of Zonites ;
and he has added to Dr. Dawson’s paper a description of the characters
which they present.
3. “On some tracks of Pteraspis (?) in the Upper Ludlow Sand-
stone.” By J. W. Salter, Hsq., A.L.S., F.G.S.
Impressions upon two slabs discovered by Mr. R. Banks in the
Downton or Upper Ludlow Sandstones of Kington, Herefordshire,
were described by Mr. Salter as the tracks of Pteraspid fish. His
reasons for assigning this origin to the imprints were partly based
upon their character, and partly on the fact that the Pteraspis was
the only known creature of the period capable of making the im-
prints. He was of opinion that the tracks were produced by fish
endowed with stiff defences to their pectoral or ventral fins. Whether
the Pieraspis possesses such defences he was not aware, though he
thought it not at all improbable.
4, “On anew Lingulella from the red Lower Cambrian rocks of
St. David’s.” By J. W. Salter, Hsq., A.L.S., F.G.S., and H. Hicks,
M.D.
Until very recently not a vestige of any organic remains had
occurred in the red rocks of the Lower Cambrian series. The fossil
now in question, which has been obtained from these deposits, is
unquestionably a Lingulella; and although apparently of the same
species as one which Mr. Salter names Lingulella ferruginea, very
common in the lowermost of the layers which have yielded Para-
doxides, this older form is distinguished by the varietal name of
L. ferruginea var. ovalis, Hicks.
5. “Observations on certain Points in the Dentition of Fossil
Bears, which appear to afford good diagnostic characters, and on the
VOL, IV.—NO .XXXIX, 27
418 Geological Society of London.
relation of U. priscus, Goldf., to U. ferox.” By George Busk, Hsq.,
F.R.S., F.G.S.
After noticing the difficulties which attend the study of the bones
of the skeleton generally in Fossil Bears, and the somewhat con-
fused and contradictory opinions as to the distinction of species
which have arisen in consequence, Mr. Busk stated that his object
in the present communication was merely to call attention to some
points in the dentition which seemed to afford more certain and
more readily ascertainable characters than could at present be drawn
from the bones, and which, at any rate in the absence of other
evidence, were a sufficiently sure guide in the distinction of species.
The characters derived from the teeth depend
1. On their dimensions, absolute and relative.
2. On their form.
Tt is not necessary, however, to consider all the teeth. The
canines vary too much even within the limits of one species to be of
much utility ; and, with certain exceptions, the differences exhibited
in the molars are not sufficiently marked to allow of their being
employed.
The teeth upon which reliance is to be placed are the upper and
lower fourth premolars, and the last molar in each jaw ; and the dis-
tinctive characters of these teeth in U. speleus, U. priscus, U. ferox,
and U. arctos were pointed out.
Tt was also endeavoured to be shown that in the size, proportions,
and form of the teeth, no essential differences could be perceived
between U. priscus and U. feroz; and the opinion was expressed
that so far as cranial and dental characters are concerned, those two
species are at present indistinguishable.
6. “On the Geology of the province of Canterbury, New Zea-
land.” By Julius Haast, M.D., F.R.S., F.G.S. Communicated by
Sir R. I. Murchison, Bart., K.C.B., F.B.S., F.G.S.
The Southern Alps in the Province of Canterbury were stated to
form the eastern wing of a huge anticlinal of granites; on the
western base of this central chain younger granites of secondary
age support semimetamorphoric strata. The eastern side of the arch
consists of a succession of huge folds of dioritic sandstones, clay-
slates, and breccias, overlain by either Upper Devonian or Lower
Carboniferous strata.
The Southern Alps are bounded on the eastern side by a belt of
old Tertiary quartzose trachytes and pearlstones, on which repose
extensive agglomeratic and tufaceous deposits,—clays, sands, and
lignite bands ; these are succeeded by thick-bedded calcareo-arena-
ceous strata; the whole broken through by Dolerites, which in their
turn are covered by sand, clays, and thin limestones, probably of
Pliocene age.
The author concluded by describing the Post-pliocene moraine-
accumulations which are found on both sides of the Southern Alps.
7. “On the Chemical Geology of the Malvern Hills.” By the
Rev. J. H. Timins, M.A., F.G.S.
From « detailed examination and analysis of the rocks composing
Geological Society of London. 419
the Malvern Hills, with a view to the determination of the chemico-
physical processes which have contributed to their formation, Mr.
Timins has arrived at the following general conclusions in regard to
those rocks of eruptive origin :—(1) that, in the intrusive trap-rocks,
the ratio of the oxygen of the silica to that of all the bases taken
together, varies progressively from 5:4 to nearly 2:1; (2) that the
relative proportions of the several bases vary considerably in different
rocks, and often characterize particular localities ; (3) that the chemi-
cal composition of the eruptive rocks does not vary according to
their age; (4) that the atomic proportions of the silica to the bases
is generally highest in the largest masses of trap, and lowest in the
smallest masses; (5) that in the same masses of trap there is an
appreciable increase in the silica towards their centres, and that the
primary source of all the trap-rocks in the Malvern Hills was nearly
a bi-silicate, which, durig the various processes by which it has
been brought to the surface, has become united, more or less, with
other substances, assimilating metallic oxides, lime, magnesia, or
alkalies, according as one or another might be locally prevalent, just
as, In modern times, the lava of Vesuvius takes up soda, and that of
Etna lime ; and (6) that in all the eruptive rocks the atomic propor-
tion of the silica to the bases varies according to a common law.
8. “On the Relative Distribution of Fossils throughout the North
Devon series.” By Townshend M. Hall, Hsq., F.G.S.
The author gave a table showing the relative distribution of the
organic remains throughout the members of the Devonian system of
North Devon. The subdivisions of the rocks employed by Mr. Hall
are :—(1) The “ Pilton Beds,” highly fossiliferous; (2) ‘“Cucullea
Zone,” a term proposed in place of that of the ‘“‘ Marwood Beds,”
and suggested by the abundance of the shells of several species of
Cucullcea, which are contained in the sandstone of the series; (3)
the ‘“ Morthoe group,” unfossiliferous ; (4) the ‘Ilfracombe group,”
containing corals and several species of Brachiopods in good pre-
servation; (5) the “Martinhoe group,” unfossiliferous; (6) the
“Tiynton Beds,” with few fossils; and (7) the “Foreland grits,”
which are without fossils, and the lowest of the series.
9. “On the Geology of the Princess Islands in the Sea of Mar-
mora.’ By W. R. Swan, Esq. Communicated by Sir R. I. Mur-
chison, Bart., K.C.B., F.R.S., F.G.S., ete.
Mr. Swan pointed out the existence of a considerable mass of
Devonian strata, partly fossiliferous, in several of these Islands, of
an age different from that of the beds of the Bosphorus, which latter
he has shown in a former paper to belong to the lowest of the
Devonian series of the Rhine. The presence of remains of fish in
the above strata, and of an ancient coral-reef in one of these islands
(Andirovitho), was also noticed.
The rocks which form the remaining portions of these Islands are
(1) Trachytic, of younger age than the Devonian strata, and (2)
Trappean, more recent than the Trachytic. The Quartz rocks, of ©
which some of the islands are largely, and others entirely composed,
are altered sandstones of Devonian age.
420 Geological Society of London.
10. “On the Sulphur Springs of Northern Formosa.” By Cuth-
bert Collingwood, M.B., F.L.8. Communicated by the Assistant-
Secretary.
The sulphur springs are situated amongst the hills near Tamsuy,
in the north-eastern corner of the Island of Formosa, and indicate
the existence of volcanic action near the surface of the region, a
phenomenon otherwise afforded by the frequent occurrence there of
earthquakes. One spring possessed the character of a mountain
torrent, and had a temperature of about 130°. The spot containing
most of the springs occupies about two acres of ground, is quite
barren of vegetation, and is covered with low hillocks of friable
rocks and débris, interspersed with shallow pits containing mud,
sand, and sometimes water. From cracks and fissures in these
depressions arose clouds of steam; and around them was strewn a
quantity of sublimated sulphur, the yellow colour of which was
visible from a distance.
11. “On the Geology of Benghazi, Barbary; with an account of
the subsidences in its vicinity.’ By George B. Stacey, Hsq.
Communicated by the President.
The town of Benghazi is built on a stratum of clay, which reposes
on a sandy foundation. It is partially protected from the action of
the sea by a reef of sandstone rocks projecting two or three feet
above the water-level. Between the reef and the land the water is
now about five feet in depth, while fifty years ago this area was dry
land; remains of buildings are to be seen under the water. ‘The
author is therefore of opinion that the land is sinking regularly, and
comparatively quickly. The fundamental rock of the country is a
Tertiary limestone, and the author has obtained from the neighbour-
hood of Benghazi specimens of Corals, Echinoderms, Oysters
Pectens, and on the surface Cardium edule.
12. “ Report on the Existence of large Coal-fields in the Province
of St. Catherine’s, Brazil.” By Edward Thornton, Esq. Commu-
nicated by the Rt. Hon. the Secretary of State for Foreign Affairs.
The existence of Coal in this district has for many years been an
established fact ; but no practical exploration had been made until
the years 1861-63, when Viscount Barbacena, having purchased a
tract of land containing the best seams, ascertained the existence of
a series of coal-beds at nine different levels, underlying a sandstone
formation, horizontally disposed, and varying in thickness from 14
to 10 feet. Analyses of specimens of the coal prove it to be of good
quality, its profitable working depending solely upon the facilities:
for transport.
13. “On the Sources of the Materials composing the White
Clays of the Lower Tertiaries.” By Geo. Maw, Esq., F.G.S., F.L.S.
In examining some of the light-coloured deposits occurring beneath
the Boulder-clay, in pockets in the Carboniferous Limestone, the
author was led to the conclusion that some of the beds of very pure
white clay could not have been derived from the mere mechanical
degradation of any previously existing materials, and analyses by
Dr. Voelcker showed that they contained similar proportions of
Geological Society of London. 421
silica and alumina as did the limestone; and Mr. Maw concluded
that they were left behind in the cavities after the calcareous matter
had been removed by watery dissolutions. The average of a
number of analyses of the white Tertiary clays of Dorset, Hants,
and Devon, showed a similar resemblance to the average compositions
of anumber of examples of Chalk and Chalk-marl, after deducting
the carbonate of lime and other matters soluble in carbonated water,
implying a derivation from the watery dissolution of the Chalk.
The geographical distributions of the Tertiary white clays seemed to
favor such an origin, and the improbability of their derivations from
the felspathic rocks was supported not only on geographical but on
chemical grounds. The average of the analyses of felspar showed
that the proportions of silica to alumina was about as three to one,
and in the average of a number of analyses of clays as two to one,
indicating that felspathic rocks could not provide the proportion of
alumina found in the white clays; but the proportion of silica to
alumina in Chalk corresponded as nearly as possible with their
composition.
14. “On the Post-glacial Structure of the South-east of England.”
By Searles V. Wood, Jun., Esq., F.G.S.
This paper was an outline of the principal points deduced by the
author from his Geological survey of the country included in the
Ordnance sheets Nos. 1 and 2, where the glacial clay approaches
nearest to the Thames Valley beds; and from a survey on a smaller
scale of the glacial beds over a much larger area. Both of his maps,
with a manuscript memoir upon the subject, have been placed by
him in the Library of the Society.
The author took up the structure at the southerly and westerly
edges of the principal tracts of glacial beds, and in the parts where
these are divided by great troughs of denudation; he showed the
manner in which the denudation, commencing at the first upheaval
of the glacial sea-bed, has descended through the Lower Tertiary
and Secondary deposits, accompanied by the formation of successive
gravel beds during its progress. His conclusion was, that the re-
moval of the Lower Tertiary strata over much of the South of Eng-
land, and the excavation of the Weald Valley, as well as the great
denudation which the Liassic, Oolitic, and Cretaceous beds have
undergone in the west of England, are to be traced principally to the
progress of the post-glacial denudation. This denudation had its
inception in the upheaval of a portion of the glacial sea-bed, and was
accompanied by a long succession of subterraneous disturbances,
which have brought up the Secondary and Tertiary rocks of the
south and west to the elevations they now occupy, and left the early
emerged portion of this sea bed (represented by the detached tracts
of the Upper and Middle Glacial formations) at lower levels than
much of the denuded area of the south and west.
The following specimens were exhibited :—
A series of Elephants’ teeth from the Norwich Mammaliferous
Crag and the Forest-bed of Norfolk; exhibited by the Rev. John
Gunn, M.A., F.G.8., showing (a) the transition of the (Lowodon)
499 Cotteswold Naturalists’ Club.
E. meridionalis into the sub-genus Huelephas; (b) the necessity for
establishing a new species, called by Mr. Gunn Leptodon, from the
fineness of the enamel ; (c) the variation of the E. antiquus from the
Post-glacial Mundesley lacustrine bed, and (d) the probable deriva-
tion of the HE. antiquus from an old type of the E. Africanus in the
Norwich Mammaliferous Crag.
Cotreswotp Naturauists’ Fre.p-ctus.—This club met for the
second time this season at Mickleton Manor, near Campden, by
invitation from Sir Maxwell and Lady Steele Graves.
After dinner, Dr. Paine, the hon. secretary, read Mr. Bravender’s
paper “On the Watershed of the Upper Thames.”
The subject of water supply having of late so much occupied
public attention the author offered some account of the watershed of
the Upper Thames, between the sources of the Thames and Oxford.
The course of the Thames is eastward, and it is fed by many small
rivers and brooks coming from the north and south. The highest
area of the watershed of the Thames is 74 square miles. The
author described in detail the various streams which feed the Thames
above Oxford, the largest the Ock, draining an area of 100 square
miles, falls into the Thames at Abingdon, below Oxford, and beyond
the district named. The watershed on the south side of the Thames,
containing 123 square miles, yields a smaller supply than the same
area north of the river. The dip of the strata is south-east, descend-
ing from the Thames on the south side, but towards the Thames on
the north side. The surface of the country slopes from the Chalk
Hills towards the Thames, and the water which immediately runs off
reaches the Thames, but at a slower rate than that from the north.
Part of that which is absorbed by the soil, and part which is lost in
the streams in the passage over open and porous beds, sinks through
those porous beds to the upper surface of the tenacious beds of the
Oxford clay, Kimmeridge clay, and the Gault, and the water de-
scending the plane of stratification in a contrary direction to that of
the river is lost to the Thames. The same remarks refer to the
watershed of the Ock. The area of the watershed of the Upper
Thames thus described is 875 square miles, and is made up as
follows :—
WEST OF THE THAMES.
Swillbrook and Thames Head .
NORTH OF THE THAMES.
SQUARE MILES.
The Churn ... ... i Seaueabriehetin ms omaendt (F133
Ampney and Marston Btooe hee ae he 324
he Cola ee sea esti cee Saat meme
The Leach ... van sees
The Brampton and Thames ‘district vel A ae alee
(Bhre NV iting itis ere amet ees basa lists ie
The Evenlode i...) ee eee ee
\ Brawender— Watershed of the Thames. 425
SOUTH OF THE THAMES. 752
Wey Raiyay iste, Boe meng Veo. eth OD s
EHichyworth districti; sas) yvelseci os deom ple
thie Colo. nes tecy ser Ake Ohsa wy ae4S
875
The rainfall over this 875 square miles may be taken at 28 inches
per annum, from which 12 inches should be deducted for evapor-
ation. The rainfall on a square mile, with this deduction, will be
1,376,710 cubic yards. But to arrive at the probable available
quantity a further deduction should be made for percolation into
porous strata, which may not afterwards be thrown out by springs,
and in consequence may not reach the Thames, but pass under it.
Some of this water we know must be brought to the surface by
faults, as at Boxwell Spring; but this can only be part of what
percolates through the beds of the upper Oolite to the surface of the
Fuller’s earth. The water which is absorbed by the porous beds of
the Inferior Oolite is very large, amounting to a third of the rainfall.
Mr. Bravender then proceeded to point out that the greatest loss by
percolation is in those streams which pass over the Inferior Oolite,
the area of which is about 106 square miles. The Churn, Coln,
Windrush, and Evenlode, lose greatly in passing over the loose and
rubbly rock of the Inferior Oolite. The average yearly loss is not
less than half the rainfall, after deducting for evaporation, leaving
eight inches of available water. The available depth over the other
strata in this watershed may be taken at twelve inches. The meau
would appear to be somewhere between nine and eleven inches.
Assuming it to be nine inches only, and the inhabitants of London
to be 3,250,000, then 272 square miles of watershed at this depth
will supply them with thirty gallons of water each per day. It will
thus appear that the watersheds of the Churn, Ampney and Marston
brooks, the Coln, and of the Ock, amounting to 2924 square miles,
will more than supply the entire population of London. The Churn,
the Coln, and the Windrush having an aggregate watershed of 301
square miles, are more than sufficient for the purpose ; and the
watersheds of the Churn, Coln, and Ock, containing 260 square
square miles, are nearly sufficient for the purpose. London is at
present said to be supplied with 643,000 cubic yards of water daily,
which is at the rate of more than thirty-three gallons per head for
three millions and a quarter of inhabitants. If this be correct,
London is more abundantly supplied with water than many other
towns. The author then gave a detailed account of a series of
observations of the actual quantity of water flowing down the river
in the twenty-four hours in August, 1864, near Castle Haton, and he
found it to be in one instance thirteen millions of gallons. In the
September following the volume of water had decreased to seven
millions of gallons. On the 8th of October only one million gallons
descended in the twenty-four hours. In the morning of this day
(Mr. Bravender said), “I had ascertained no water was passing
down the Thames at the bridge at Cricklade; there was no
424 Correspondence.
water in the river there except in the hollows in a few places. I
examined the Churn, which flows into the Thames near Cricklade,
and found that river completely dry at South Cerney, and on de-
scending the stream to where the water from Boxwell Spring joins
the Churn I observed a considerable quantity of water flowing into
the Churn from Boxwell Spring. On visiting Boxwell Spring,
about a quarter of a mile up the brook from this junction, I found it
discharging about the usual quantity. I had sometime before ascer-
tained the flow of this spring, and did so at this time, and found the
discharge about one million one hundred thousand gallons in twenty-
four hours. The fact is that the water passing Water Eaton was
from the Boxwell Spring, and in passing over about three miles of
porous gravel and somewhat peaty soil there was a loss of one
hundred thousand gallons per day at that time. This loss would
eventually find its way into the Thames lower down the vale. It
may be observed that from the middle of August to the middle of
October scarcely any rain fell, and that which did fall was absorbed
immediately, and made not the slightest difference to the water in
the Thames. Our observations extended over forty-five days, from
the 24th August to the 8th of October, and during this period the
entire supply of the Thames above Water Haton ceased, except what
was supplied by Boxwell Spring.” Mr. Bravender concluded by
giving an account of the loss of water in the Churn by percolation,
being the results obtained by a series of experiments in 1859, show-
ing a loss of upwards of three millions of gallons per day. The loss
of water descending the Coln is much greater than that of the Churn.
Two other papers followed ; first, some notes by Mr. John Jones,
“Qn Drybrook section in the Forest of Dean;” second, “On the
Denudation of the Cotteswolds,” by Mr. E. Mitchell Wilts and
Gloucestershire Standard, June 29th, 1867.
CORRESPONDENCE.
FISH-REMAINS FROM THE NORTHUMBRIAN COAL-FIELD.
To the Editor of the Gronocican Macazinn.
Str,—The haste with which the critic (in Grou. Mag., August,
p- 878), not waiting for the ‘paper,’ has assailed the ‘abstract,’ in
the July number, p, 828, would seem to show him moved by some
smaller feeling than the desire to know a little more about the fossils
of the coal. Howsoever that may be, any remarks which Mr.
Atthey, after perusal of the paper and inspection of the fossils
therein described, may have to offer will meet with due and respect-
ful attention from me. I would, meanwhile, request your readers
kindly to suspend their judgment; and I appeal to them, not so
much on my own account, but lest they should attach to the words,
“a short time ago” (p. 878), a meaning different from that which
Mr. Atthey, speaking from knowledge, must entertain. In justice to
Mr. T. Craggs I have to state that I have been favoured by receiving
Correspondence. 425
from that gentleman specimens from the shales of West Cramling-
ton and other places since June, 1865. Both gentlemen are personally
unknown to me, though it is possible that they may have been of
the number of those who submitted fossils to my inspection after a
lecture I previously delivered at Newcastle-on-Tyne.
Ricup. OwEn.
SPIRIFER CUSPIDATUS AND SYRINGOTHYRIS TYPA.
To the Editor of the GzotoctoaL MAGAZINE.
Srr,—Absence from home and other causes compel me to defer
my reply to Dr. Carpenter’s and Mr. Davidson’s papers on the
structure and histology of “Syringothyris typa” for a short time
longer, when I shall be able, from ample materials in my possession,
to show clearly that it is no other than Spirifer cuspidatus, as repre-
sented by imperforate and tubeless specimens. ®
Wiuiiam Kine.
BELMONT, near GALWAY,
July 8th, 1867.
THE CLAY-BED NEAR STANNAGE, DERBYSHIRE.
To the Editor of the Grotoctcat MaGazine.
Str,—I went up to Stannage the other day for the purpose of
determining whether the bed of clay, seen by Mr. Binney, and
mentioned by Mr. Maw in his paper in the June number of your
Macazine (page 247), was a member of the Carboniferous system or
a more recent deposit. There can be no doubt that it is the former.
A small pit has recently been sunk close to Spitewinter in order to
get clay, it may be some fifteen or twenty feet deep, but as it was
partly filled up with water I had no proper means of ascertaining the
exact depth. The upper part exposes a section of thin shales,
beneath are sandy clays and clay, and lastly, a thin seam of coal,
which appears to have been only just touched. There is a good
deal of clay under the peat in the immediate neighbourhood, and it
has been dug into somewhat extensively still further to the west
near the old Cupola marked on the Ordnance Map. When I have
time I will endeavour to find out, if possible, the boundaries of the
deposit ; immediately above it, to the north, is the fine escarpment
of what I conclude to be the first grit. May not the shales above-
mentioned correspond with those spoken of by Messrs. Hull and
Green in their paper on the Millstone Grit, in No. 79 of Geol. Journ.
They say ‘shales, with a thin coal at the bottom, west of Buxton,
lie below the Rough Rock.” A thick bed of shales has also been
exposed by a landslip on the north bank of the river Hipper, below
Catholic hill, on the north-west side of Stannage. I may mention
that the grit escarpment of Stannage has every appearance of having”
been an old sea-worn cliff; it has hollows or rock-pools in its face
or on its summit; the escarpment is on the south-west side of the
hill; on the other side the slope is more gradual, and three or four
426 Correspondence.
terraces look very much like old beach lines, but as they have not
been cut into I cannot say for certain.
A reference to the Ordnance Map, No. 82, south-west, will explain
the relative position of the localities above referred to.
I am, yours truly,
J. M. Mrtxo.
St. THomas’s Parsonacr, Brampton, CHESTERFIELD,
July 22nd, 1867.
DR. T. STERRY HUNT’S THEORY OF THE EARTH.
To the Editor of the GrotocicaL MAGAZINE.
Str,—I have read with considerable interest the very ingenious
theory of the “Chemistry of the Primeval Harth,” by Dr. Hunt,
which is contained in your issue for August, and beg your permission
very briefly to ask the Doctor how his theory is compatible with the
following facts respecting the mean densities of the sun and larger
planets, or whether the theory of their extensive hollowness does not
more satisfactorily account for their low mean densities than does
that of the sun, the earth, and, by inference, all the planets increasing
in density to their centres.
The following are approximately the mean densities of the sun and
the larger planets :—
SLU eed ee 1:42 Uranus: cor ie0h ice eee leO
SMUPIGET Meee) peach een cman con: INeptumer stds wae estes a MOO
Satin). iees wees seca O10
and those of the smaller planets are—
Mercury son eesy pec ¥: 11056 Bartha, ‘eer fects cy aces fled
Wenus Seige rete eso O16 Mars) Ayes. Mcccaiinacs) jen eoro
The densities of the asteroids are unknown, but should they be
ascertained, I venture to predict that they will probably be found of
higher mean density than are any of the planets just enumerated.
All the large planets have very low mean densities; all the smaller
planets have high and nearly uniform mean densities.
How are these facts to be accounted for on Dr. Hunt’s theory of
condensation and increase of density to the centres ?
. I am, yours obediently,
NEWwcastTLE-on-Tvne, T. P. Barxas.
August 6th, 1867.
ON THE SEQUENCE OF THE DRIFTS IN THE EASTERN COUNTIES:
To the Editor of the Guotocican Magazine.
Dear S1r,—With reference to Mr. Wood’s suggestion, that I
should give complete sections from his “upper drift” to the beds
exposed on the coast, I wish to say that I have not materials by me
to work out the details he asks for, and it appears to me that the
point at issue would not be explained by exact particulars of surface
contour, and the position of the crags in relation to the overlying
drifts. There is no difference of opinion as to this, and all are
agreed that the gravels underlying the Boulder-clay of High Suffolk
correspond in height with much of the gravel superimposed on the
Correspondence. 427
clay in the coast cliffs. This I admitted in my first paper, and am
quite aware it presents a prima facie case in favour of Mr. Wood’s views ;
and furthermore on the view I suggested I should expect that the
variety in the component materials of Mr. Wood’s “ middle drift”’
would prevent any certain distinction being observable between
them and the gravel seen on the coast, even if a section happened to
expose their junction.
The difficulty Mr. Harmer raises seems to me to be equally
applicable under any view; if, for example, the coast beds at Trim-
mingham are much above the level of Norwich why are they not, on Mr.
Harmer’s view, intercalated between the crag at Thorpe and the beds
Mr. Harmer has identified with Mr. Wood’s “‘ middle drift.” Surely
some cases ought to occur among the numerous exposures of Norwich
Crag in Norfolk, in which the Boulder-clay of the Cromer cliffs can be
seen to intervene between the Norwich Crag and Mr. Wood’s “‘ upper-
and-middle-drifts.’ The absence of Boulder-clay as the highest
member of the cliffs of the Norfolk coast (the equivalent of that in
High Suffolk) I have already admitted in my first paper might, on
Mr. Wood’s views, be the result of denudation; but its absence
throughout the district, wherever Boulder-clay is known to form the
base of the cliffs, is rather remarkable. Mr. Gunn and Mr. Wood I
am aware believe that it does exist in the low cliffs at Pakefield
and Corton, but if all three divisions of the drifts are developed at
these points, within a height of thirty or forty feet, it involves the
difficulty of a great attenuation of Mr. Wood’s two upper divisions
after they leave the high land and descend more than 200 feet to the
sea-level. At Corton, the assumed equivalent of Mr. Wood’s “upper
Boulder-clay” is but from three to nine feet thick; at Hasboro’
ten feet; whilst in High Suffolk the Boulder-clay attains a thickness
of at least sixty feet.
The occurrence of derivative fossils would seem to be rather an
uncertain guide in the classification of the drift series. Mr. Taylor
(at page 258) observes that the coast clay has been formed princi-
pally by the wreck and denudation of the Lias (and the editor adds,
of the Kimmeridge clay) ; but this is really no distinctive feature, as
the Bedfordshire Boulder-clay, which is evidently an extension of
the High Suffolk clay, is literally loaded with these fossils, and the late
Mr. Trimmer (in the quotation given by Mr. Gunn) described his
“upper Boulder-clay” (the “upper drift” of Mr. Wood) “as character-
ized by an abundance of oolitic detritus.” Unless it is assumed that
the materials of the Boulder-clays have been derived from a distance,
and in each from different directions, it seems probable that succes-
sive deposits in the same localities should contain similar derivative
fossils.
In the observations I have made I have wished rather to leave
the succession of the drift deposits an open question than to lay
down unequivocally any order of sequence. It is a subject that may
well be held in suspense, and the evidence in relation to it seems
scarcely of a nature to base exact conclusions upon, or to afford
materials for mapping out the various subordinate divisions of
428 Correspondence.
the drift series. The existence, however, of Mr. Harmer’s “ Third
Boulder-clay,” as a distinct formation, seems to depend on the
certainty of the coast beds being inferior to those of High Suffolk.
The small patches of Boulder-clay in the Yare Valley are clearly
more recent than the drifts that have been cut through to form the
valley ; but does it not seem less improbable that the coast beds may
be identical with them, than that these isolated patches of a marine
deposit should have been the solitary result of the submergence during
which they were formed ?
Grorce Maw.
BrenTHatt Hatt, Brose ey,
August 6th, 1867.
“THE LOB-WORM EPOCH.”
To the Editor of the GuotogicaL Macazine.
Str,—Colonel Greenwood’s remarks in the August number of the
GronocicaL Macazine on the “ Lob-Worm Epoch” tempt me to lay
before your readers a few facts concerning the rocks of that period,
as shown in this neighbourhood, and the results obtained by their
examination during the last few years.
Mr. Salter and myself have for some time felt convinced that most,
if not the whole, of the Cambrian rocks belonged to a fossiliferous
period, and accordingly in our own report to the British Association
in 1865, on the “Lower Lingula-flags”” (Menevian group) and its
fossils, it was stated that, “‘though the purple band series have not
yet yielded any definite traces of these higher forms of fossils, we
are scarcely warranted in looking upon that as a proof of their absence ;
neither is it likely that so rich, though limited, a fauna should come
so suddenly into existence.” Since then I have been fortunate enough
to find fossils in these identical purple beds, which prove the facts at
that time only conjectured.
In a paper by Mr. Salter and myself, read before the Geological
Society on June 19th, an account is given of the finding of a Lingu-
lella in the red rocks of the Lower Cambrian-rocks, hitherto deemed
quite destitute of higher organisms than worms, and belonging to the
very series mentioned by Mr. Baily. I have found also, subsequently
to the reading of the paper referred to, a whole colony of species
(trilobites, etc.) still lower down, showing, beyond a doubt, that
much, if not the whole, of the so-called ‘“‘ worm epoch” represents
a time when animals of much higher forms than worms were in
existence, and flourished in the seas of the period. I therefore feel
satisfied that if active explorations be carried on in North and South
Wales, it will be proved that the series throughout is truly fossiliferous,
but I am also sensible that some time will be required to decide
the fact, since the working of the strata is, in many ways, difficult,
and the deposit from its very nature, as a rule, unfavourable to the
exhibition of organic remains.
Moreover we are sure to find, especially in so extensive a series,
much that is but very slightly fossiliferous, or, indeed, almost barren,
intervening between colonies of rich faunas. Such is really the case
Correspondence. 429
with nearly all the groups already found, scarcely a vestige being
seen in most of the beds which separate the several colonies, upon
which usually we come quite abruptly. This I look upon also as one
of the chief causes why a Lower Cambrian fauna has not ere now
come to light.
I am, sir, yours truly,
Str. Davin’s, Henry Hicks.
Tih August, 1867.
PHOLAS-BORINGS IN DEVONSHIRE.
To the Editor of the GnotocicaL MaGazine.
Sir,—As I have observed in your journal for July some remarks
on Pholas-borings found 200 feet or more above the present high-
water-mark, on the cliffs in the neighbourhood of Torquay, perhaps
one or two words on these ancient rock-perforations may not be out
of place by one who has more than once made them the object of his
search and examination.
Some time ago, in the year 1864, I happened to be visiting I]fra-
combe and its neighbourhood, and, amongst other coast scenery, I
spent a day on Woollacombe sands, extendmg my ramble to the
summit of the hills called Morte Point, not forgetting to search care-
fully far above the present sea level, its rocky wall and face, when
practicable, for the marks or signs of some ancient stone-boring
mollusk.
And here I ought to mention that Mr. Pengelly was the first
person from whom I learnt the supposed origin of these peculiar
marks or holes in rocks near the sea-coast. As I minutely looked
over its pointed heights facing the sea, after some trouble I found a
number of perforations from an inch to two inches in size, and about
one inch or a little more in depth. I cannot speak exactly, as I
write now from my recollection of what I then saw.
Some of the rock-cuttings were much worn by the action of the
weather: some, no doubt, were naturally formed by frost and other
causes ; while some, in a more sheltered part of the hill, appeared
nearly as perfect as when left by their excavators.
In my own mind the evidence is so conclusive that these small
hollows are Pholas-borings, or the work of some Mollusk, and that
the rock, now 200 feet or more above the sea-level, must have been
once under water at every tide.
Some five or six years before this examination of the hills at
Morte Point, I happened to be staying in Plymouth, and, having a
little spare time on hand, I closely explored the rocks which fringe
the sea-beach below the Hoe, and there I found a number of freshly-
formed holes in the limestone rock, covered at every tide, about the
size of the Pholas-borings, only they extended much deeper in the
rock, while at the same time there appeared to be a kind of hard,
shining coating on the inside of their holes, much like the inner
part of an almond shell. The reason, perhaps, why these ancient
stone-borings are seldom noticed, is the fact, I think, that the old
Sea-coast is partly washed away, for it is only (so far as my observa-
430 Correspondence.
tion extends) when the rock is some little distance inland, as at
Morte Point, Devon, that they are to be found.
It is possible that what I have stated may attract the notice of some
of the numerous excursionists at this season of the year, and, if so,
there would be no difficulty in verifying the few observations I have
ventured to send to your Magazine for publication.
I am, sir, yours truly,
WILLIAM GIBBENS.
CHELMSFORD, EssEx,
August 9th, 1867.
THE BOULDER-CLAY OF THE THAMES YVALLEY.!
To the Editor of the GuotocicaL Magazine.
Drar Srr,—Any one wishing to see the Boulder-clay on the
southern side of the range of heights that form the northern
boundary of the Thames Valley, cannot do better than go by train
to Romford, and walk to Havering-atte-Bower, three miles from
that place. The road is very pleasant and the view from Havering
beautiful. The Boulder-clay can be seen in a pit on the right hand
side of the drive leading from Havering to Bedfords, as well as in a
pit very near the letter D in “lodge” on the Ordnance Map. The
Boulder-clay is full of fragments of Chalk, more or less striated, of
quartz pebbles, and transported blocks and fossils. The fossils have
been caught up by the ice principally from the Oxfordian and Kim-
meridgian zones, and consist of Belemnites, Ostrea dilatata, and other
bivalves. In one fragment of shale I found Ammonites biplex and
in a striated nodule from the Kimmeridgian there was a very well
preserved shell of that species. The great interest of this deposit is
its position to the south of the northern boundary of the Thames
Valley proper.—Yours truly,
W. Boyp Dawxrns.
Upminster, Romrorp.
June 22nd, 1867.
MIS CHne AA HOUSs.-
eee
A Dywamicat THErory of THE FIGURE OF THE HARTH, PROVING THE
PoLEs TO BE ELONGATED.” By F. C. Baxewertt.
Tt is the author’s object to prove that the general figure of the
earth is that of a lemon, rather than of an orange; in short,
that our planet must be elongated at the poles. ‘The question,”
he states, “is capable of being determined, without much stretch of
reasoning power, by all who possess a knowledge of the first prin-
ciples of mechanical science. The only thing especially required is
that its consideration should be freed as much as possible from the
mists of prejudice and the trammels of authority.”
1 This letter was unintentionally omitted from the August number of the Gxroxo-
eicAL Macazine.—Enit.
2 8yo. London, 1867, pp. 26. (Weale).
Miscellaneous. 431
The points which Mr. Bakewell has endeavoured to establish are :
1st. That the ordinary illustrations of the action of centrifugal
force, as applied to the commonly assumed figure of the earth, are
entirely delusive. |
2nd. That the disturbance of equilibrium by centrifugal force in a
fluid sphere rotating in space could not be counteracted by the ac-
cumulation of matter at the equator.
ord. That if it were possible that the matter of a fluid sphere put
in rotation in space could accumulate at the equator under the in-
fluence of centrifugal force in opposition to gravitation, it would fly
off altogether.
Ath. That it would be impossible, therefore, for a fluid mass of
matter rotating in space to assume the form of an oblate spheroid.
5th. That it would be equally impossible for a solid spherical
rotating nucleus covered with water to assume that form.
6th. That in accordance with the law of motion, that action and
reaction are equal and in opposite directions, a fluid mass of matter
rotating in space must accumulate at the poles to resist the action of
centrifugal force, and in the form of greatest resistance to that force.
7th. That a prolate spheroid is the only figure in which the
particles of a rotating mass of matter could adjust themselves in
accordance with the form of equilibrium.
8th and lastly. That geodetic measurements, and the appearance of
the heavenly bodies, tend to confirm the dynamical theory, that the
earth is a spheroid rotating about its longest diameter.
Norres on Arrypa.—Mr. R. P. Whitfield has published (in the
19th Report on the New York State Cabinet) some observations on the
Internal Appendages of the genus Aitrypa; with a notice of the
discovery of a loop, connecting the spiral cones. By carefully
cutting and preparing favourable specimens, the author has found
that mm place of the short crural processes so often figured, there is
an entire and continuous loop connecting the spiral cones, in a very
similar manner to that shown by Professor Hall to exist in his
genus Zygospira, but having its connection with the spiral ribbons
at a point relatively much nearer to their origin on the hinge-plate ;
still more distant, however, than the points figured by Mr. Davidson
and others. This loop, so far as observed, is confined to the rostral,
or posterior part of the shell, and never passes over or in front of the
Spires, as in Professor Hall’s genus. The author has succeeded in
ascertaining the existence and form of this loop in several different
varieties of Atrypa reticularis, as well as in A. spinosa, of Hall; and
he finds that in the different varieties of A. reticularis, it is subject
to considerable variations of form. The author further remarks,
that should these differences prove constant in the several varieties,
they may, when considered in connection with the differences in
external features, and perhaps some modifications in the form of
the spiral cones, serve as guides in establishing specific characters
in this group of shells. In a note, appended to his paper, Mr.
Whitfield states that since the preparation of his paper he has ex-
4392 Miscellaneous.
amined numbers of specimens of Atrypa, showing sections of the
spires, and he has observed that the volutions composing the cones
vary in number, with the increase in age and size of the shell;
while specimens of the same size have about the same number of
volutions.
ANALYsIS OF A Buack SpinetLteE.—M. Pisani has communicated
to the Academy of Sciences, Paris, the analysis of a black spinelle
from the Haute Loire. It is as follows :-—
JIT ES sooqobatoonoue: veee 59°06 | Ferrous Oxide ............... 18°60
Ferric Oxide ............++ 110; 7/2) | PMlaonesianenencceasacescee saree 17°20
It is remarkable from its crystalline form—an octohedral pyramid—
which has not before been recognized in spinelles. This mineral is
chiefly found in Haute Loire, but it is also met with m the igneous
rocks of Auvergne.— Comptes Rendus.
ERRATA FOR JULY AND AUGUST.
Page 300, line 6, from top of page, for ‘‘ Surturbrand” read Surturband.
» 9821, ,, 9, from foot of page, for “silicia” read séica.
» 9827, 4, 25, from top of page, for ‘‘ breach” read beach.
7p SUE jy HEE +p a for “outline” read ‘‘ outlier.”
», 982, ,, 5, from top of page, for ‘ Ordnance Memoir,” read ‘“ Geological
Survey Memoir.”
6, from top of page, for “ Hall” read “ Hai.”
” 9 99
Dr. T. Sterry Hunt’s Lecrurs.—We hoped to have received from Dr. Sterry
Hunt some corrections of the Short-hand Writer’s Report of his Lecture at the Royal
Institution, on ‘“‘The Chemistry of the Primeval Harth,’’—(See Gzou. Mac. for
August, p. 357,)—but his unexpected departure for Canada having prevented, we
hasten to give such errata as we have been enabled, with the assistance of our col-
leagues, to detect, and, at the same time, we beg to apologise to Dr. Hunt for their
occurrence :—
Page 361, line 26, from top of page, for ‘increases the act of fusion,” read “ raises
the melting point.”
» 9 3 988, from top of page, delete ‘‘largest.”
ay LO oy oT 3 rs for ‘‘the metallic bases’’ read “the other
metallic bases.”
25, from top of page, after the words “‘may be absorbed,” insert
‘‘and given off.”
»» 9) 16, from foot of page, for “‘seven times” read “several times.”
Sey OB) wy) pallill a 9) for “consist only of lime,” etc., read ‘ contain
only lime,” etc.
364, lines 14 and 15, from foot of page, for ‘the remains of calcareous
animals” read “the calcareous remains of animals.”
365, line 39, from top of page, for ‘‘ disruptive” read “ eruptive.”
FF Ae 55 for “decomposed” read ‘‘recomposed.”
», 366, ,, 24, from foot of page, for ‘ Orchid-house” read ‘‘ Orchard-house.”
ESOT © ages % for “Thompson” read ‘‘ Thomson.”
if 9 9; oe iN dy for ‘mutation’? read ‘‘nutation.”
» 368, ,, 17, from top of page, for “radiation” read “ convection.”
SEL gee i ms 95 for “ gault”’ read ‘‘ Coal.”
We should, in fairness to Dr. T. Sterry Hunt, state that, owing to his absence in
Paris during the month of July, we were unable to submit a proof of the Report, for
his correction, before its publication in the August Number of this Magazine; and
thus the errors above stated escaped detection,—Eprr.
9 ” ”?
THE
GEOLOGICAL MAGAZINE.
No. XL—OCTOBER, 1867.
(Ope KG aN (Aaa PAS RI sas
—————j___
T.—On THE CHEMISTRY OF THE PRimEVAL Hartus.!
By Davin Forsss, F.R.S., ete.
T will, no doubt, be admitted by all, that it is highly conducive to
the advancement of any science, that some one of its votaries,
more courageous than his colleagues, and endowed with a more
generalizing turn of mind, shall, by the comprehensive and exact
study of accumulating observations, endeavour to elevate himself
above the level of the more plodding but invaluable collectors of
facts, by attempting the arrangement and organization of such data,
and the deduction therefrom of the laws which regulate their
existence and govern their movements.
Without such generalization, science itself would be but a mere
accumulation, or, rather, chaos of unconnected observations.
All honour is therefore due to such leaders in science, whose
success should be appreciated in proportion to the difficulties which
had to be overcome before it had ultimately been attained. It must
not be forgotten, however, that in this century of rapid progress,
science, in the pursuit of truth, becomes each day more and more
severe in insisting upon exactitude in research, and in demanding
that no hypothesis or theoretical deduction be accepted as correct
before it has run the gauntlet of stringent scientific scrutiny, in order
fully to test its soundness.
In this present communication it is mtended to take into con-
sideration the general views in chemical geology, recently expounded
by the well-known chemist, Dr. Sterry Hunt, during his late visit
to this country, and which have already appeared at length in this
MaGazinz, in a report of a Lecture on the Chemistry of the Primeval
Earth, delivered by that gentleman in the theatre of the Royal
Institution.’
Although but few of the opinions expressed in this lecture are
original, the manner in which Dr. Hunt has combined them as a
whole, in his argument, is sufficiently at variance with what has
1 Jn order not to extend this communication to too great a length, and to avoid
going deeper into the more purely chemical points, these latter have been considered
in greater detail by the author in a paper ‘‘ On some points in Geological Chemistry,”
in the Chemical News of October 4th, 1867, to which the attention of the readers of
the GroLtogicaL MaGazine is herewith directed.
2 Gov. Maa., Vol. LV. pp. 857-369. See also pp. 432 and 477,—Eprr.
VOL, IV.—NO. XL. 28
434 Forbes— Chemistry of the Primeval Earth.
hitherto been generally received in Europe, as to lead to the in-
ference that Dr. Hunt thus gallantly throws down his glove in
order to invite discussion upon the subject.
After taking the opinion of several well-known geologists and
chemists upon the lecture in question, the author of these remarks
concludes that in this case, at least, silence does not imply consent,
since, without exception, all referred to were at variance with more
than one of the views therein put forth. He would therefore have
gladly seen the challenge of Dr. Hunt accepted by some one more
able than himself; and, consequently, before entering the lists thinks
it proper to explain that he has been induced to do so by Dr. Sterry
Hunt’s special invitation to “ have a friendly fight,” which he must
confess he was not unwilling to accept,’ especially as in a late dis-
cussion that gentleman’s opinions, when quoted by one of his
admirers (in the pages of this MaGazinx) in opposition to his views,
were put forward with a show of authority which opinions as yet
neither generally accepted nor confirmed can be entitled to.’
In his introduction Dr. Hunt adopts the nebulous hypothesis of
the earth’s origin, assuming the chemical elements to have all been
originally present as intensely heated gases, uncombined, and in a
state of “indifference” to one another, which he accounts for by
referring to Deville’s experiments on the dissociation of certain
gaseous compounds at intensely high temperatures. A subsequent
lowering of the temperature is then supposed to have brought about
the combination of the elements, and afterwards the condensation of
their compounds into the shape of an igneous fluid globe.
So far, Dr. Hunt arrives at the conclusion advanced in the last
century by Hutton, the propounder of the plutonic theory of the
world’s origin, which assumed the world to have been at one time a
sphere of molten matter solidified by refrigeration. In considering
the results attendant upon the cooling of such a molten sphere,
writers, however, differ greatly in opinion; the majority have
supposed the formation of a solid crust of more or less thickness,
enclosing a still liquid igneous kernel; more lately some have
advocated the existence of a solid central kernel along with a similar
external crust, whilst the intermediate space contains still liquid
igneous matter; and, lastly, evidence has been recently brought
forward indicating the possibility of a solid, or nearly solid globe.
Dr. Hunt insists upon the earth being a globe solid to the core,
which had solidified from the centre outwards to the exterior, and
further represents the first of these views, hitherto the most generally
received and maintained by many of the most able geologists and
1 In the belief that fair discussion advances science, by developing energetically
both sides of the question ; such discussions should however only be indulged in by
those who can give and take with equal good grace, without losing temper or
deviating from the subject at issue by indulging in recriminations or personalities,
such as Dr. Hunt at the close of his lecture alludes to, as having disturbed the social
relations of the geologists of the last century, and which unfortunately sometimes
creep into discussion even in this enlightened age. ;
2 Groz. MaG., Vol. 1V. p. 287. ‘The author still agrees with “ most geologists ”
in opposition to the opinions referred to.
Forbes— Chemistry of the Primeval Earth. 435
mathematicians, to have been “supported to a great extent by
fallacious reasoning.”
That such observers, however, could, as Dr. Hunt imagines, have
been led astray by the exceptional-case of the crystallization of
water, is sufficiently refuted by the intimate knowledge of the
behaviour of melted lavas, slags, metals, etc., everywhere displayed
in their researches; so that other explanations of the “fallacious
reasoning” alluded to must be sought. Dr. Hunt therefore informs
us that the solidification could not have commenced at the surface,
because the congealed crust is heavier than the molten fluid from
which it had cooled—i.e., ought in other words to sink into the
same.
Most of the readers of these remarks, have doubtless seen large
open castings produced at foundries, and the question may therefore
be put to them, whether they ever have observed in such cases, no
matter how large the casting might be, that the pellicle or crust,
formed upon the surface of the molten iron, sank down into the metal
below it (unless purposely broken up by force) ; yet the cast iron,
when solid, is well known to be heavier than when in the fluid state.
On the contrary, it supports itself in the same manner as the
external surface of an igneous sphere would do, if exposed to a
cooling action, operating simultaneously upon the whole of its
external area.
But, admitting even that it would sink, and supposing with Dr.
Hunt that the mean density of the earth is 5:3, and of the solid
exterior crust at one-half this, or 2°65, and also that the specific
gravity of this latter, when in a fluid state, would be considerably
lighter, say 2°3: then surely Dr. Hunt will not expect it to be believed
that this solid crust of sp. gr. 2°65, can smk deep down into the
fluid mass of a globe possessing a mean density of 5.3.1
If broken up by force, the fragments of such a crust might be
imagined to sink a short way, say a few miles, through the upper or
lighter stratum ; which at the surface was of a density of 2:3 (be-
coming rapidly denser in descending, as the pressure increased by
the heightened superposed column of liquid matter) until it came to
rest in a liquid stratum of its own density, where it would float
(in a solid state, if Dr. Hunt is to be believed in asserting that
under the extra pressure at this depth, its fusing poimt would be
elevated, and so prevent its absorption into the main mass).
Such an action would, on the contrary, tend to bring about the
very formation of a superficial crust, like that which Dr. Hunt
denies, for this action once commenced, would go on solidifying at
the exterior, sinking to a certain depth, then resting there, super-
posed on that which had previously congealed and descended, and so
on, until a solid crust was eventually formed, extending from this
depth to the surface.
1 If we suppose the mean density of the earth to be 5:3, and that of the surface
crust to be 2°65, and further imagine the earth to be composed of three consecutive
layers of equal thickness, and of density increasing in arithmetical progression, we
should have 2°65 for the density of the outermost zone, nearly 10°7 for that of the
middle one, and about 18°8 for the centre.
436 Forbes— Chemistry of the Primeval Earth.
Dr. Hunt then tells us, that the cooling of the liquid globe would
be “like the cooling of a great bath of metal or sulphur,” and that
it “would commence at the centre and extend outwards toward the
surface.” This may fairly be questioned. Any one who ever cast a
bullet knows how long the centre remains fluid after the exterior
shell is solid; the founder knows how difficult it is to get his cast-
ings perfect, with their centres solid; and the mode of causing metals,
as bismuth, lead, etc., etc., to crystallize, by allowing as large a
mass of the fluid metal as possible to solidify exteriorly, and then
pricking a hole through the crust, so as to let out the still fluid cen-
tral metal, is familiar to all, as well as, probably, the fact that this
same proceeding is commonly employed to obtain crystals of
sulphur.
But Dr. Hunt will doubtless object, that the above experiments
were not made under pressure, and, to demonstrate that solidifi-
cation must in such case have commenced from the centre, refers
to the experiments of Hopkins and Fairbairn, as proving that the
fusing points of bodies are elevated by pressure.
Fully aware that the fusing points of certain bodies are actually
raised when under pressure, and prepared also to believe that
silicates may be amongst such, still the author, after a careful
analysis of both Hopkins’ experiments,! and those of Bunsen,’ can-
not find such conclusive evidence in the same, as Dr. Hunt in his
lecture would lead his audience to infer.
The results of these experiments condensed into a few words are
as follows :—Hopkins and Bunsen both find by experiment that
certain organic compounds (spermaceti, wax, stearine, and paraffine) -
actually have their melting and freezing points elevated (but in a very
irregular manner), when exposed to pressures of from 1 to 793 atmos-
pheres (15 to 11,880 lbs. per square inch)’; further, Hopkins shows
that sulphur: has likewise its fusing point elevated by a pressure
from 1 to 520 atmospheres (15 to 7,790 lbs. per square inch), but that
after this up to 793 atmospheres (11,880 lbs. per square inch), the
highest pressure tried, the ratio of increase of temperature to pres-
sure diminishes greatly, which might be supposed to indicate that at
still higher pressures the fusing point might again diminish and
~ even become depressed instead of elevated. No allusion is made to
Mr. Hopkins’ statement that in the case of such metallic alloys as he
had tried, ‘‘ that he had not detected any elevation of fusing temperature
acquired by increasing the pressure.”
Even allowing however that the fusing points of bodies in general
are elevated by pressure, it does not necessarily follow that the
centre of the earth must have solidified before or even at the same
time with the crust, unless it is also taken for granted that the
earth’s mass is perfectly homogeneous throughout, or at least com-
1 Brit. Association Report, 1854, p. 57.
2 Poggendorf. Ann., vol. 81, p. 562. 1850.
8 The nature of such organic substances being totally different from any to be met
with under the circumstances here under consideration, much dependence could not
be placed upon the similarity of behaviour of inorganic compounds.
Forbes—Chemistry of the Primeval Earth. 437
posed of substances all of the same degree of fusibility, neither of
which views are likely to meet with general acceptation.
The density of the exterior of the earth with which geologists are
acquainted, is known to be only about one-half of the mean density
of the earth’s mass as a whole, and at first this was accounted for
upon the supposition that its components became more and more
dense in depth, owing to the pressure of the superincumbent mass ;
experimental research tends, however, to show that a limit is soon
reached, beyond which the compression or increase of density
becomes less and less in relation to the force employed ;’ and there
are consequently strong reasons for believing that the central parts of
the globe must consist of much denser bodies, such as metals and
their metallic compounds.
As we well know that such metallic bodies are infinitely more
easily fusible than the silicious rocks of the superficial crust, it may
be fairly advanced, that the difference between the fusing poimts of
these bodies would more than counterbalance the influence of pres-
sure in causing solidification at the centre of the globe, by the
elevation of the temperature at which the central mass could remain
in fusion.?
The above reasons make the author come to the conclusion that
Dr. Hunt has not produced sufficient evidence to prove that the
earth is really entirely solid; and he still adheres to the opinion
that the earth does enclose a vast reservoir or reservoirs of still fluid
igneous matter in its interior.
The chemical composition of the cooling globe, and specially of
its external crust, next demands consideration. Dr. Hunt believes
the primitive crust to have been composed of the alkalies, alkaline
earths, earths and metallic ‘bases in combination with silica, and
surrounded by a dense acid atmosphere, consisting of hydrochloric,
sulphurous, and carbonic acids, along with steam, nitrogen, and
probably the excess of oxygen. The author would protest against
such an atmosphere, and for reasons about to be explained, does not
believe that it ever did or could have existed.
We are told in the first place, that “all the sulphur would be
diffused in the atmosphere as sulphurous acid.” The author, on the
contrary, believes that the sulphur would have combined with the
heavy metals, forming dense sulphides, which would at once sink
below the lighter external crust and there be protected from oxida-
tion. Nor does he consider it probable that at such a moment of
general combination an “excess of oxygen” could possibly be
present in an atmosphere highly charged with sulphurous acid.
Dr. Hunt alleges that we should find “all chlorine in the form
of hydrochloric acid,” which is also contrary to the opinion of the
1 And the author thinks it probable that the same would also be the case with the
relations of fusing points to pressure.
2 In opposition to this view, it might be said that the densest of all metals, Plati-
num, is also one of the most infusible. To this we answer, that many of the
compounds of Platinum, say with zine, tin, arsenic, ete., are so extremely fusible as to
melt in the flame of a candle.
438 Forbes— Chemistry of the Primeval Earth.
author, who considers that the chlorine would chiefly, if not entirely,
be in combination with the metals of the alkalies and alkaline earths,
as chloride of sodium, ete.
According to Dr, Hunt, the hydrochloric acid in this atmosphere
was derived from the mutual reactions of sea-salt, silica, and water.
This, in the first place, is supposing the pre-existence of compound
bodies, in a case where he had previously informed us that there
were only dissociated elements engaged in the formation of this
igneous sphere. For the sake of argument, however, let it be
admitted that sea-salt, water, and quartz were present, then it is still
contended that the reaction, described by Dr. Hunt, could not have
taken place. All chemists know that quartz, water, and sea-salt, if
heated together in a confined space, or if the vapor of water and salt
be passed over highly heated quartz, that such a reaction would take
place forming hydrochloric acid gas along with silicate of soda.
This, however, could never occur in nature in the case under con-
sideration, for long before the quartz had attained a heat sufficient
to enable it to act upon the salt, all the water would have evaporated
into space; and if the heat were continued, the vapour of the salt
would follow, leaving the quartz behind.
As the greater part of the sodium is considered to have been at
once combined with the chlorine, it follows, of course, that the
silicate of soda could not have played so important a part in the
formation of the primary crust as is ascribed to it by Dr. Hunt ; and
there would also be no necessity for the extraordinary theory that
the saltness of the sea is due to the rain of hydrochloric acid
“ flooding the half-cooled crust” with a highly heated acid deluge,
which extracted the soda from its silicate, leaving the quartz
behind ;* and it is therefore conjectured that neither geologist nor
chemist will be contented with this explanation of the salt in the
sea.
Having thus opposed the views of Dr, Hunt, as set forth in his
lecture, the author of this communication will in a few words sketch
out the chemical reactions which he supposes to have been charac-
teristic of this period of the earth’s history.
The act of combination of the elements is regarded by him as
having given rise to a molten sphere, surrounded by a gasiform
atmosphere, both of which were composed of concentric layers or
zones of different densities and chemical composition.
This sphere, it is imagined, would arrange itself into three grand
zones, (each zone, probably, containing sub-zones), somewhat as
follows :—An external zone, or crust of highly acid silicates, the
bases being chiefly alumina and potash, with minor quantities of
soda, lime, magnesia, oxide of iron, etc. ; below this a second zone of
1 The silica produced from such decomposition of silicates is of the specific
gravity of 2°2, is soluble in alkaline solutions, and does not polarize light, which is
not the case with the silica contained in any of the older rocks, which Dr. Hunt
supposes to have been so formed. The chemical and physical properties of the
silica of such rocks indicate them to haye been derived from the breaking down of
acid rocks analogous to granite.
Forbes— Chemistry of the Primeval Earth. 439
silicates, more basic, and of greater density; the bases being lime,
magnesia, alumina, oxide of iron, with soda, and but minor quantities
of potash, etc.; and still deeper a far denser sphere, containing
metallic bodies, more or less combined with sulphur, arsenic, etc.
On the other hand, the atmospheric zone, next the solidified crust
of the earth, would be composed of a dense vapour of those com-
pounds, volatile only at a high temperature, amongst which the
chloride of sodium or salt would be probably the most prominent,
above this a stratum of carbonic acid gas, and then of water, in the
form of steam, whilst the oxygen and nitrogen would be elevated
still higher.
It is imagined that such an arrangement would, on cooling, first
condense the lowest atmospheric zone’ (vapour of salt and other
chlorides, etc.), on to the already solidified crust of the earth ; cover-
ing this with a layer of these substauces, in a solid state*; upon a
further reduction in temperature the steam in the atmosphere would
now be condensed on to this layer, which it would, in great part,
dissolve, forming the ocean, which consequently would be salt from
the first moment of its appearance on the face of the globe. The
atmosphere now surrounding the globe would contain less oxygen
and all the carbon, in the form of carbonic acid, (excepting only the
amount of that acid already absorbed by and carried down with the
rain water), but otherwise it would probably not differ much in com-
position from what it is at present.
From this stage in the earth’s history, the author believes that all
the changes which have taken place in the globe, up to the present
time, have been effected by agencies similar to those going on in it
at this present day ; rocks were formed from the wearing down and
disintegrating action of the atmosphere or weathering of the primitive
crust,* and the subsequent stratification of the debris, so formed by the
action of the sea; just as they are at present in the course of formation
from the disintegration of pre-existing rocks. Hruptions of igneous
matter from the still fluid interior* from time to time disturbed and
broke through the primitive crust and the rock strata above it,
in course of formation from its debris, just as at the present day
(though possibly on a somewhat smaller scale), similar outbursts are
produced by volcanic action. The products of such older eruptions
are almost identical, in chemical composition, with those of the
newer period. Thus the result of chemical analysis of the most
ancient granite often cannot be distinguished from that of an
1 The zone of carbonic acid gas would be heavier than that of steam; 1 cubic foot
of the latter weighing at 212° only 26517 grains, whilst 1 cubic foot of carbonic
gas would weigh 642°09 grains, at same temperature.
2 A rough calculation shows that the layer of sea salt alone would be sufficient to
clothe the entire sphere with a crust of salt some 10 feet in thickness.
3 This action would, no doubt, be much facilitated in the older geological epochs,
by the amount of carbonic acid in the atmosphere being so much greater than at
resent,
a The contraction, consequent upon the cooling of the original sphere, would,
doubtless, greatly disturb the previously comparatively even surface of the crust, and
produce cracks and fissures, the sides of which, from their unequal subsidence or
elevation, would often be dislocated and form lines of faults.
440 Forbes— Chemistry of the Primeval Earth.
ordinary volcanic trachyte, and the basaltic rocks from recent
volcanoes resemble very closely those from far more ancient periods ;
in fact it is often the case that such rocks can only be distinguished
from one another by a very careful study of their less prominent
characters.
Taking them as a whole, the main distinction between the erup-
tions of the most ancient and most modern epochs is, that in the
earliest period the acid rocks, or granites, predominated, whilst at the
present day the acid volcanic rocks, or trachytes, are in less propor-
tion, the more basic rocks predominating.
Several reasons to account for this circumstance have been put
forward, and are well worthy of consideration.
To return, however, to Dr. Hunt; he states that after the
energetic action of the acid deluge had ceased, a second similar but
slower process of decomposition and solution of the crust commenced
by the action of, in this case, carbonic acid with water, resulting in
the formation of clays which remained behind, whilst solutions of
the carbonates of soda, lime, and magnesia, poured down into the sea
where they precipitated, first the alumina, and subsequently the
heavy metals. In such events geologists, although as yet unsuccess-
ful in so doing, might still hope to find beds of alumina or of the
metallic oxides or carbonates alluded to, amongst the older strata.
As no beds of such character are known to occur in nature, this
hypothesis must, however, be received with some distrust.’
The next assertion of Dr. Hunt, that the limestones have been
formed by the precipitation of the lime in the sea by a solution of
carbonate of soda, is so decidedly at variance with all the conclusions
hitherto arrived at by geologists, zoologists, and microscopists, that
it cannot but be disputed, and there is sufficient evidence now
produceable to refute this hypothesis.
In making the assertion, that “the whole of the carbonates of
lime which make up the calcareous strata—the marbles and various
limestones which we find on the earth’s surface are so formed,” Dr.
Hunt at the same time states that he is quite aware that geologists
are of opinion “that these limestones are the result of organic
action,” but no doubt classes this opinion as another sample of the
“fallacious reasoning” which he supposes them to indulge in, and
will probably be surprized to learn that zoologists also will dispute
his further assertion, that “animals can only appropriate the car-
bonate of lime which they find ready formed,” and that they, in
opposition to this assertion, believe that marine animals can utilise
the other salts of lime, existing in abundance in the ocean.
Had the limestones been so formed by precipitation, whether hot
1 It may here be remarked that Dr. Hunt, in his lecture, does not allude to what
became of the sulphuric acid, which would be the ultimate product of “all the
sulphur” burnt into sulphurous acid, and afterwards condensed from the atmosphere
into the ocean; for since it may safely be asserted that there is fully as much (if not
more) sulphur as chlorine, the sea formed, according to Dr. Hunt's hypothesis,
would be as much a solution of sulphate of soda as of seasalt, and he can hardly
suppose it to have been precipitated, for it is well known that no beds of sulphate of
any importance whatsoever occur in the very oldest formations,
Forbes—Chemistry of the Primeval Earth. 441
or cold, they would have, from the moment of their deposition,
possessed a decided crystalline structure, visible when examined by
the microscope ; as in the case of stalactites, stalagmites, travertines,
ete. ; this, however, is not the case.
Sorby’s microscopical researches prove satisfactorily that all
limestones, from the most ancient up to the most recent, are solely
formed of the debris of organisms,’ and that they do not possess any
crystalline structure whatsoever, unless when altered by subsequent
infiltration, or other metamorphic action.
Dr. Hunt next proceeds to explain that the magnesian limestones,
dolomites, and gypseous beds owe their origin to chemical “reactions
hitherto unsuspected,” and that his experimental researches have
proved them to have been formed at a period when the surface of
the earth was covered by a dense atmosphere of carbonic acid, and
that this “theory is confirmed by climate, by vegetation, and by the
singular series of reactions which hitherto have been a perplexity to
chemical geologists.” ?
The microscopical and chemical investigations of Sorby have,
however, eliminated the most conclusive evidence against the cor-
rectness of this theory of precipitation, and shown the magnesian
limestones and dolomites alluded to by Dr. Hunt (whether of the
Devonian, Carboniferous, or Permian period) to be mere mechanical
ageregates, or true limestones of ordinary character subsequently
altered by infiltration of magnesian matter.
This result had been long before arrived at by geologists, as the
study of these rocks in the field showed that such magnesian lime-
stones were frequently only portions of the ordinary limestone beds
peculiar to the formation itself, altered at places, apparently by some
then unexplainable chemical action. This was found to be the case
even with limestones pertaining to the Devonian and Carboniferous
formations, in which period it has long been advanced that an
atmosphere rich in carbonic acid did exist.
As all geologists know that the grand development of magnesian
limestones, dolomites, and gypseous beds really took place in an
epoch when numerous air-breathing animals, both vertebrates and
invertebrates, lived upon the face of the globe, it will surprise them
to think that Dr. Hunt can imagine these animals living in an atmo-
sphere of carbonic acid.
The next point in this lecture to which attention is directed is a
very important one in its general bearings, although it is to be feared
1 Even the chalk is entirely so composed, notwithstanding that its external appear-
ance is so like that of a precipitated carbonate of lime.
2 Dr. Hunt seems to be quite unaware that in the Brit. Assoc. Report, 1856, p. 77,
Sorby has fully explained these reactions, that Harkness (Brit. Assoc. Report, 1857, p.
68) applied similar experimental investigations of Regnault, to explaining the dolomi-
tization of the Carboniferous limestones near Cork; and, lastly, that the results of his
researches on the artificial atmosphere of carbonic acid, which he has thought worthy
of bringing before the French Academy (Compt. Rend., 1867, p. 815), so far from
being new, have for the last twenty-two years at least, if not much longer, been
employed on a large scale in the manufacture of magnesian compounds in both
England and Ireland.
449 Forbes—Chemistry of the Primeval Earth.
that the attractions of palzontological research have caused it to be
of late, in a great measure, shelved by geologists in general.
It has lately been the fashion, especially amongst many of the
younger votaries of the science, to “‘ pooh-pooh” the igneous origin of
eruptive rocks in general, and of granite in particular. A careful
study of the literature of the subject shows, however, that this
secession from opinions, previously all but universally adopted, has
originated in the writings of one or two able but one-sided men of
science, blindly followed, as is usual in such cases, by adherents who
reason not for themselves, or who have either not sufficient leisure
or inclination to examine into the true merits of the question. The
author fully believes, however, that had anything like a careful
study of what has already been published (pro et contra) upon this
subject been made, that not only would an explanation or answer
have been discovered to meet any and all of the arguments brought
forward in opposition to the igneous origin of such rocks, but that
such as are open to conviction would with the author of these
remarks have come to the conclusion that nothing has as yet been
advanced which can in any way tend to prove the eruptive rocks to
have an origin differing from that of those rocks produced by vol-
canic action at the present day.
At present, however, only such arguments as are advanced in Dr.
Hunt’s lecture can be discussed, and these only in all brevity, since
the space already occupied by this communication has extended
beyond its proposed limits.
As evidence against the non-igneous origin of granite, Dr. Hunt
asserts ‘that the composition of the primitive crust would have
excluded free silica ;” again, “that this very quartz, which is one of
the constituent elements of granite, is only the result of a secondary
process ;” and yet again, in the report of his lecture contained in the
‘Chemical News,” vol. xv., p. 317 (revised by himself previous to
publication), ‘that granite is in every case a rock of sedimentary
origin, as it includes in its composition quartz which, so far as we
know, can only be generated by aqueous agencies, and at compara-
tively low temperatures.’’!
In making such statements, it may be asked whether Dr. Hunt is
aware of the immense masses of undoubted volcanic rocks scattered
all over the surface of the globe which contain abundance of free
quartz? Amongst others, the Ponza Islands, for example, under
the very shadow of Vesuvius; the hundreds of miles of volcanic
outbursts of quartz trachytes, from the still active volcanoes situated
along the range of the Andes, in South America, as well as numerous
examples which might be referred to in other parts of the globe,
although, unfortunately, not in Canada. Does not Dr. Hunt know
that the admirable memoir of Sorby, contained in the Quart, Journ,
1 If we, with Dr. Hunt, believe that the temperature increases in proportion to
the pressure, then, as Sorby has shown that the quartz of the granite of Aberdeen
has solidified at a pressure equal to a column of seventy-eight thousand feet of rock,
this alone would be quite sufficient to refute the statement of comparatively low
temperatures.
Forbes— Chemistry of the Primeval Earth. 443
Geol. Soc. of London, vol. xiv., shows how perfectly identical in
structure this volcanic quartz is with the quartz of granites (both
containing in common, fluid, vapour, gas, and stone cavities , and
that this accurate observer has concluded that the modern volcanic
trachytes and old granites have one common igneous origin, in
which, as is the case in volcanoes, water has played some part.'
That the metamorphic rocks have been formed from ordinary
sedimentary strata, by their having been “depressed so that they
come within the action of the earth’s central heat” may be disputed ;
but before doing so it might be as well to learn from the author of
this ingenious theory by what mechanical arrangement he supposes
strata on the surface of the earth to be lowered down into a globe
solid to the core. The further development of this theory, assuming
a similar action to have produced the eruptive rocks emitted by the
volcanoes of the present day, is at once strongly protested against ;
for how, may it be asked, are we, according to this theory, to
account for the fact, that voleanic rocks taken from any quarter of
the world, no matter how far distant from one another—from
Iceland or Terra del Fuego, from the Islands of the West Indies or
from those of Polynesia—that in all cases such rocks possess an
absolute identity in chemical and mineralogical composition ; in
physical and in optical properties. Can any geologist be expected
1 An argument has been brought forward against the igneous origin of granite,
from the fact that the specific gravity of the quartz in granite is 2-6, whilst the
density of silica artificially fused before the oxyhydrogen blowpipe is only 2:2. If
this style of argument is admitted in philosophical reasoning, then the silica of the
carapaces of infusoria ought also to have been formed by fusion, since its specific
gravity is only 2:2, as is also the silica deposited from its gaseous compounds with
fluorine, etc. Sorby’s before-mentioned researches have shown that the quartz in
granite has solidified under enormous pressure. It might therefore reasonably be
expected to possess a higher density than such as has been fused artificially, without
having been subjected to pressure at all. Another argument is found in the fact that
some of the more fusible minerals in granite have often solidified and crystallized
before less fusible ones; in reply, it may be stated that this is also the case in modern
layas; in those of Vesuvius, it is common to find that the refractory Leucite has
crystallized before the easily fusible Augite, and to be superposed on crystals of this
latter mineral. It has further been argued, that rocks like granite occasionally
enclosing minerals containing water, could not have been formed by igneous fusion ;
independently of Sorby’s discovery that the quartz of volcanic rocks and the felspar,
nepheline, idocrase, etc., ejected from Vesuvius, do contain water: specimens taken
out of the lava current from Etna, whilst still flowing in March, 1865, contained fine
crystals of Stilbite (with 16 per cent. of water). Bunsen’s researches (Taylor’s Scient.
Memoirs, Nov., 1852) have long ago experimentally proved that hydrated silicates,
analogous to those occurring in eruptive rocks, might be formed at high temperatures
and retain their water at such temperatures as long as enclosed in the matrix ; if ex-
tracted from this, however, the water could be expelled by the application of a very
gentle heat. Laurent has also showed that borate of Potash, fused at temperatures
above the melting point of Silver, retained water which, singularly enough, might be
expelled in bubbles by reheating the vitrified mass over a spirit lamp so as hardly to
soften it.— Whilst correcting the proofs of this paper for the press, the author has had
his attention directed to a communication made by Professor Ansted to the British
Association, ‘‘ On the Passage of Schists into Granite in the Island of Corsica,” in
which (if the report in the “ Dundee Advertiser,’’ Sept. 10, be correct) the learned
Professor cites, in support of his views, the results of Mr. Sorby’s researches in a
manner apparently quite at variance with the conclusions arrived at in that gentle-
man’s memoir,
444 Jukes—On the Gorge of the Avon.
to believe that such rocks have been formed by the melting up of a
mere mechanical aggregate of rock-debris, possessing no analogy
whatsoever, and whose chemical composition, etc., is known to vary
to the widest imaginable extremes.
In conclusion the author cannot but express his feeling that it is
doing an injustice to the memory of such noble minds as Hutton,
Playfair, Hall, Humboldt, Von Buch, and others, to bring against
them the narrow-minded charge of their wishing to create the earth
“entirely by fire.” Their writings abound in evidence proving
that they never overlooked the all important agency of water in
nature’s operations, and when claiming for igneous action its true
share they based their plutonic theory upon the study of such
agency as is exemplified in volcanos, in which, from the first, the
co-operation of water (although in some, at that time, incompre-
hensible manner) was acknowledged ; and not upon any idea of
“dry fusion,” which could only have originated in the brains of
their antagonists.’
TI.—On tHe Gorce or THE Avon, AT CLIFTON.
By J. Bezte Juxss, F.R.S.
| OBTAINED, the other day, on my way into South Devon, another
peep at the Bristol Channel, and the gorge of the Avon, at
Clifton, which I had long been wishing for. It showed me, as
I anticipated, that the hypothesis of atmospheric erosion, which
I was compelled to adopt, a year or two ago, to explain the formation
of the river valleys of the South of Ireland, is applicable to the
Clifton gorge as to all other similar places.
With the existing form of the ground traversed by the Avon,
above Bristol, it would, of course, be quite impossible for the river
to cut a channel across the Clifton Downs. Fill up the gorge of the
Avon with the mass of Carboniferous Limestone and Old Red Sand-
stone, that once occupied it, or even half fill it, and the waters
of the Avon, after forming a lake, would, long before they overtopped
that dam, run into the sea by Nailsea, as pointed out by Sir H. T.
De la Beche.
This, however, only shows that the surface over which the Avon
originally ran into the Severn, was not the present surface. All the
rivers originally ran over a surface considerably above the present
one, and they have continued to run in the same courses during all
the wasting of the rock, by which the old surface has been trans-
formed into the present one.
The rivers have been, at once, the channels by which the eroded
matter was removed, and the motive power of the eroding machinery.
Colonel George Greenwood’s phrase of “ Rain and Rivers,” gives
us the whole secret in three words.
1 Apparently an application of the “‘sensation”’ principle to geology.
2 It is nearly half a century ago since Scrope not only pointed out the important
part played by water in volcanic action, but further expatiated upon the difference
between volcanic fusion and ordinary melting.
Jukes—On the Gorge of the Avon. 445
_ Let anyone travel through the country with Professor Ramsay’s
geological map in his hand, together with the sheets published by the
Geological Survey, for details. Let him then look at the fretted and
gullied escarpment of the Oolitic range from Northampton to Somer-
set, and recollect (as shown by Mr. Topley in a former number of the
Gerot. Mac.), that the sea does not form escarpments, but cuts sections.
Let him follow the level sheets of Lias and Trias, down the coasts of
Somerset and Glamorgan, till they abut against the Paleozoic hills,
on both sides of the Bristol Channel. Returning to the Oolitic
escarpment of the Cotteswolds, let him mark how the Oolitic outliers
get fewer and smaller as he recedes from it, and let him connect
them with the broad outlier of Inferior Oolite, on Dundry Hill, five
miles south of Bristol, and the still more curious little patch of
it that caps the Lias peak of Brent Knoll, which rises from the flats
of Bridgewater. He cannot fail to come to the conclusion that not
only the Lias, but the Oolites, once spread in level sheets across the
district now occupied by the estuary of the Severn up to the Pale-
ozoic Hills of South Wales.
The outlying patches of Lias that occasionally cap the red marls
through Warwickshire, Staffordshire, and Cheshire, prove that the
Lias, at least, formerly extended to, and wrapped round, the Palzo-
zoic hills of North Wales.
Let the observer then stand on the highest point of Clifton Down
and look up to the superior height of Dundry Hill, some six miles
to the southward, and he would see at once that the extension of the
old Oolitic sheet would pass some two or three hundred feet over his
head. That the Lias itself rested directly on the Paleozoic rocks is
shown by the fact of sheets of it still stretching across the Carboni-
ferous Limestone to the north-east of Durdham Down, still resting in
patches on the Backwell Hills to the westward of Dundry, and on
that of the Mendips, in the neighbourhood of Harptree.
The Lias then formerly reposed on the Carboniferous Limestone
of Clifton Down and the Oolite spread over that. The Severn and
its tributaries, flowing over this Oolitic plain, of course cut channels
in it. The original form of the surface was such as to turn the Avon
towards the Severn instead of towards the Thames. ‘The course it
originally took, it has ever since maintained, cutting down through
the horizontal Mesozoic cover, and through any Paleozoic rock it
found underneath, in whatever position it might lie, or whatever
materials it might be composed of. During part of the time the
whole country must have been higher out of the sea than it is now,
and the rivers must have run as continuous streams over the land
which is now the bottom of the Severn estuary, till they had cut
down to the level where. the solid rock would now be met with,
under the estuary mud. If the whole country got a hoist of one or
two hundred feet, the Avon would be a rapid brook at Clifton, fret-
ting over the rocks at the bottom of the gorge and continuing the
work of channel-cutting, which at the present level of the land it has
been obliged to suspend.
While the rivers have been cutting their channels the rain and its
446 Jukes—On the Gorge of the Avon.
resulting streamlets have washed off a large part of the softer Mesozoic
cover of the country and disclosed the old Paleozoic hills and ridges.
Many of these are formed of Carboniferous Limestone, which, in the
south of Ireland, has itself been worn down into valleys and plains.
The reason is that in the south of Ireland the limestone was never
protected by any Mesozoic cover, but has been subject to the dis-
solving power of the rain-water during the whole period. About
Bristol it was so protected for a great part of the time. Had it not
been so, the only hills remaining thereabouts at the present day
would probably have been those of Old Red Sandstone and the un-
destroyed Mesozoic outliers.
The whole of England may, doubtless, have stood at a lower level
than it does now during part of the time that this process has been
going on, as well as at a higher level. When it was at a higher
level the action was accelerated and extended; when it was at a
lower, it was retarded on the part that remained dry land, and
entirely stopped for all the ground that sank below the sea. Sink
England now 600 feet, you make an island of Wales, and a cluster
of islets of the rest of the country. On its re-elevation you might
find beds of sea-shells on that which had been the sea-bottom, and
sea-worn crags on the sides of the straits that had connected Bristol
and Liverpool. That, however, would be no proof that the sea
eroded those straits. It would be nearly as reasonable to suppose
that a canal was excavated by the water that lies in it. 'The sea
would waste the coasts doubtless, and deposit the materials at the
bottom of the straits, and on the re-elevation of the country the rivers
would have to set to work to scour out their old channels and the
rain to wash the valleys clean again.
While looking into De la Beche’s Manual for his description of
Clifton, I caught sight of a passage in which, quoting from a French
author, he enforces the impossibility of the Meuse having cut its
own channel through the hills of the Ardennes, because in the
higher parts of its course it runs over ground much lower than the
Ardennes, where it is only separated from the Seine by hills of a
hundred feet or so in height. This lower ground is formed of the
Oolites, with the New Red rising gently from underneath them on
the east. The Moselle also runs across that country on its way from
the northern slopes of the Vosges to Treves, where it turns and cuts
by deep winding channels through the much loftier ground of the
Hifel and the Hundsruck. These, like the Ardennes are made of
siliceous slate-rock.
The hypothesis of atmospheric erosion equally applies here. The
Oolitic, perhaps even Cretaceous, plateau over which all three rivers
orginally ran, had a surface higher than that part of the Ardennes
and the Hifel, across which the rivers Meuse and Moselle took their
course. The rivers have ever since been steadily cutting their chan-
nels deeper and deeper along the courses they first selected, and the
districts adjacent to them have been lowered by atmospheric waste in
proportion to the depth the rivers cut down to, and the difference in
the nature of the rocks they cut through in different places. Where
Whitaker—On Subaérial Denudation. 447
those were hard siliceous slates, the slopes of the river-valleys are
steep precipitous cliffs, from the summits of which we look over the
old plateau, somewhat wasted, doubtless, but still approximating to
its original form. Where those rocks are New Red, or Oolite, or
Chalk, the slopes of the river-valleys are mostly gentle and far-
spread ; a few isolated hills and ridges may have summits that ap-
proximate to the level of the old plateau, but these are few and far
between, and none of them, perhaps, actually reach it by one or two
hundred feet.
I believe that anyone, in any part of the world, who will apply
the key here given to the problem of the production of the present
“form of the ground” will find that if he adjust the wards properly
it will unlock it for him.
Til.—On SusarriaAt DEenupaAtion, AND ON CLIFFS AND EscARPMENTS
oF THE CHALK AND Lower Tertiary Bens.
By Wituiam Wuiraxker, B.A. (London), F.G.S.,
Of the Geological Survey of England.
[PART I.]
[A paper read before the Geological Society of London, May 8, 1867. ]*
1.—Introduction.
OR some years geologists have more or less agreed in the view
that the present features of the earth, whether hill, valley, or
plain (with some small exceptions, as volcanic outbursts) have been
formed directly by denudation; though indirectly disturbances,
whether faults upheavals or sinkings, have of course had their
effect in determining the flow, so to speak, of the denuding agent.
So far all is harmony, the differences of opinion being only on the
comparative effect of the two forces, disturbance and denudation :
but beyond this all is discord, and of late there has been much
debate on the question by what means the surface of the earth has
been worn away, and its rocks carved into their present form.
Many papers have been written on the origin of valleys escarp-
ments lake-basins etc., some of which are clear statements of care-
fully observed facts, with unprejudiced and logical reasonings there-
from ; whilst others, on the contrary, are little else than assertions
of belief, and some are made up largely of groundless suppositions
and false analogies. It seems hardly to be known that to fit one to’
take part in such an enquiry along and careful examination of nature
is needed, and that, to quote the words of a geologist of the last cen-
tury, “it is not to common observation that it belongs to see the effects
of time and the operation of physical causes in what is to be per-
ceived upon the surface of the earth.’
It may not be amiss therefore to analyse the evidence given by
some special classes of rocks; and to avoid being charged with advo-
cating opinions on slight acquaintance with the formations chosen for
1 The title given by the editor to the short abstract in the Society’s Journal (Vol,
EXiil. p. 265) is not quite correct.
2 Hutton’s Theory of the Harth, vol. ii. p. 238,
448 Whitaker—On Subaérial Denudation.
illustration, it may be well to state that for the last ten years I have
been doing Geological Survey work in Cretaceous and Tertiary dis-
tricts ; work which has slowly convinced me against what I believed
before (as many of my colleagues have been in like manner convinced)
that the irregularities of the earth’s surface have been chiefly caused
by subaérial actions, by rain rivers frost and springs, forces that
can be seen in action every day and therefore have come to be looked
on as things of nought. I do not say however that the sea has
done nothing towards the formation of these irregularities; but allow
that many of the present features may have been worked out and
strengthened along lines sketched out as it were beforehand by
the action of the sea, which is granted I believe by most who hold
the subaérial theory, although they are often misrepresented as deny-
ing that the sea does anything. In some cases the marks of marine
action may have been little effaced, but for the most part they must
have been destroyed when exposed for a long time to the wasting
powers that reign over the land.
2.—Authors who have advocated the Subaérial Theory.
It seems strange that there should now be any discussion on the
subject, and that instead of subaérial denudation being the accepted
theory of the day it should be held by a minority only (albeit that
minority contains many well-known geologists, and increases every
year) ; for the power of atmospheric actions in wearing away rocks
was most ably treated of more that 70 years ago by Dr. Hutton,
whose great work’ is not so well known as it should be, and indeed
is known mostly in a secondhand way, through Professor Playfair,
who followed and defended the views of his friend and master.’
After this Mr. Scrope proved their truth for a special district, showing
that in Auvergne rivers have worn away large masses of hard rock,’
and said that “the same agents (rain and rivers) must have been at
work everywhere else, and produced results as stupendous during
the same (comparatively) recent period,” and ‘since, by a fortunate
concurrence of igneous and aqueous phenomena, we are enabled to
prove the valleys which intersect the mountainous district of Central
France to have been for the most part gradually excavated by the
action of such natural causes as are still at work; it is surely in-
cumbent on us to pause before we attribute similar excavations in
other lofty tracts of country, in which, from the absence of recent
volcanos, evidence of this nature is wanting, to the occurrence of
unexampled and unattested catastrophes, of a purely hypothetical
nature.”
1 The Theory of the Earth, 2 vols., 8vo.; Edin., 1795. See especially vol. 1. p.
304, and vol. ii. pp. 3-5, 98, 99, 138-40, 143 (quotation from the French), 157, 205,
209, 210, 236, 245, 295, 296, 401, 466-8, 498, 528, 529, 534, 535, 547.
2 Illustrations of the Huttenian Theory, 8vo.; Edin, 1802. Reprinted in vol. i. of
Playfair's Works, 1822. See pp. 104-7, 110-14, 378-6 of the original edition (= pp.
117-19, 122-5, 370-2 of the later one.
3 Memoir on the Geology of Central France, 4to., Lond., 1827. Ed. 2, 8vo., 1858
pp: 37, 38, 97, 158, 159, 205-9, 213, 244 ; and GEOL. Maa., Vol. IIJ..p. 1938 (1866).
Mr. Scrope touched on the subject before in his “ Considerations on Volcanos,” 8vo.
Lond., 1825 (pp. 96, 97, 188, 139, 214, 216).
Whitaker—On Subaérial Denudation. 449
M. Charpentier also has expressed his belief in cae formation of
the valleys of the Pyrenees by their contained streams ;' and in later
times Colonel Greenwood has taken up the subject and strongly de-
fended the Huttonian doctrine ;? Mr. Prestwich has treated of the
formation of valleys by the rivers flowing in them in the south-east
of England and the north-west of France ;? Mr. Godwin-Austen of
the power of rain in the formation of deposits of loam, etc. (and
therefore in the destruction of something else beforehand) and of
the formation of Chalk valleys by ‘‘ meteoric” actions ;+ Professor
Ramsay, of the ploughing-out of lake-basins by glaciers and of the
denudation of the Weald ;° Professor Jukes, of the cutting-out of
certain valleys and escarpments by subaérial action;® and M.
Ch. Martins, of the formation of some inland needles of rock by
weathering.’
Sir C. Lyell too has adopted the suba@rial theory toa great extent,
as may be seen by the following, which he has kindly allowed me
to quote from a letter written shortly after this paper was read :—
“T have long ago modified my opinions on denudation, and I now
agree with you in considering that the escarpments round the Weald
are not inland cliffs, as I formerly supposed, although at some points
the sea may have entered through transverse valleys and modified
parts of them. Two arguments, namely the fact of the escarpment
of the Lower Greensand being parallel with that of the Chalk,* and
the fact that the sea cuts its cliffs successively through different forma-
tions and never keeps for such great distances to one formation only,
are I believe unanswerable.” And with regard to the pinnacles and
needles of Chalk in the valley of the Seine (see p. 452), Sir Charles
continues: “ Hiver since I convinced myself that the sea had not
gone up the valley of the Somme farther than Abbeville, the highest
point at which marine shells occur, ] had great misgiving as to its
having been so effective as some eminent French geologists have
thought in excavating the valley of the Seine. Liven if the sea, or
the rise and fall of the tide, extended as far as Rouen and further, I
cannot conceive its having gone up so far as to have made the pin-
nacles of Chalk near Andelys, without supposing a submergence in-
consistent with what we must infer respecting Picardy, which
appears, like the Wealden district, to have kept its head above water
during and since the Glacial Period.”
The following authors have also, in one way or another, supported
1 Essai. sur la constitution géognostique des Pyrenees, 8vo., Paris, 1823, p. 25.
2 Rain and Rivers, 8vo, Lond., 1857. Kd. 2in 1866.
3 Phil. ‘Trans., vol. 154, p. 247; Quart. Journ. Geol. Soc., vol. xix. p. 497 (1863).
4 Quart. Journ. Geol. Soc., vol. yi. p. 94 (1850); vol. vil. pp. 121-6, 139, 131
(1851) ; vol. xi. pp. 118, 119 (1855); vol. xiii. pp. 63,71 (1857).
5 Ibid. vol. xvill. p. 185 (1862); Phil. Mag., vol. 28, p. 2938 (1864); vol 29, p. 285.
(1865); The Physical Geology and Geography of Gt. Britain, 8vo., Lond. Ed. 2.
1865).
6 Brit. Assoc. Rept. for 1861, Trans, of Sections, p. 54; Quart. Journ. Geol. Soc.,
vol. xviii. p. 378 (1862); Gor. Mae., vol. ili. p. 232 (1866), vol. iv. p. 444. (1867).
7 Bull. Soc. Geol., France, 2 Ser., t. xii, p- 314 (1855).
8 I believe that Professor Ramsay started this argument against the marine origin
of escarpments.—W. W.
VOL. IV.—NO, XL. 29
450 Whitaker—On Subaérial Denudation.
the theory of subaérial denudation: Dr. C. Le N. Foster and Mr. W.
Topley,’ who have worked out in detail the question of the Wealden
denudation, the latter having also touched on other districts ;? Mr. A.
Geikie,? Mr. A. H. Green,* Mr. G. Maw,° Mr. A. R. Wallace,® Mr. A.
B. Wynne,’ and, to some extent, the Rev. O. Fisher.’ In far countries,
too, Professor Dana,’ Professor Hind,” Mr. J. P. Lesley," Sir W.
Logan,” Dr. Newbury,"* and Professor Whitney,“ in America; Dr.
Haast, in New Zealand; Mr. T. Belt, in Nova Scotia; and Dr.
Rubidge, in South Africa,” have borne witness on the same side.
It is remarkable that most of the subaérialists are of English race
(using that name in the broadest sense), but few foreign geologists
allowing that anything but the sea or a cataclysm can have given
rise to hills or valleys of large size; and also that a great number
of these subaérialists are or have been employed on Government
Geological Surveys, and therefore have been accustomed to be con-
stantly in the field, earning their bread by their hammers, and
spending their days in the more or less detailed examination of the
geological structure and physical features of the districts which it
has been their duty to survey and describe.
3.—General Remarks.
The following pages treat of escarpments and not of ordinary
valleys, because the formation of the latter by other agents than the
sea is now more generally understood. The same kind of argu-
ment holds in both cases, but the subaérial cutting out of valleys
is at first sight clearer than that of escarpments, and perhaps is sup-
ported by more direct proof.
1 Quart. Journ. Geol. Soc., vol. xxi. p. 443 (1865).
2 Grot. Maae., Vol. III. p. 485 (1866), and Vol. IV. p. 184 (1867).
3 Notes of Travel by Vacation Tourists, 1861.—The Geology and Scenery of
Scotland, (1865).
4 Geol. Survey Memoir on Sheets 81 N.W. and S.W., p. 86 (1866).
5 Grou. Maa., Vol. III. pp. 344, 489, 575 (1866).
6 Quart. Journ. of Science, vol. iv. p. 33 (1867).
7 Mem. Geol. Survey, India, vol. v. p. 201 (1866).—Gzrox. Mae., Vol. IV. pp. 8,
345 (1867).
5 ee Journ. Geol. Soe., vol. xvii. p. 1 (1861).
9 United States Exploring Expedition during the Years 1838-42, vol. x., Geology,
4to., Philadelphia, 1849, pp. 384-92, 526-83, 670-7.—Manual of Geology, 8yo.,
Philadelphia, 1863, pp. 635-42, 676.
10 Quart. Journ. Geol. Soc., vol. xx. pp. 125, 126, 128-80 (1864), where references
to the author’s other notes on the subject are given.
11 Notes on a Map to Illustrate Five Types of Earth-Surface, 4to., Philadelphia,
1866.
12 Geol. Survey, Canada—Rept. of Progress to 1863, 8vo., Montreal, p. 889.
13 Part 3 (Geology) of Lieut. Ives’ Report on the Colorada River of the West.
1861. References to other remarks on denudation by this author are given in Pro-
fessor Hind’s paper referred to above.
14 Report on the Geological Survey of the State of Wisconsin, vol. i, pp. 117-26
1862).
\ 15 Report on the Geology of Canterbury, New Zealand ;—and Quart. Journ. Geol.
Soc., vol. xxi. pp. 129, 180 (1865).
16 Quart. Journ. Geol. Soc., vol. xx. p. 463 (1864)—in abstract only. The paper
has been printed in full in Trans. Nova Scotian Institute of Nat. Sci., Vol. I. Part
.p. 91.
117 Grou. Maa., Vol. III. p. 88 (1866).
Whitaker—On Subaérial Denudation. 451
There are many points which have already been more or less gone
into in detail by others, and therefore need but a passing notice
here,’ amongst them are the following :—
(1.) Escarpments always run along the strike, whilst actual cliffs
rarely do so (and then only for a short way), but cut through rocks
without regard to it; whereas if both had been formed by the sea
they should be more alike.
(2.) The bottom of an escarpment does not keep to one level, but
rises slowly inland, or towards the watershed, that is in accordance
with the drainage-level of the country and without regard to the
level of the sea. Professor Ramsay has called my attention to the
fact that sometimes the base at one place is higher than the top at
another.
(3.) Sea-cliffs run comparatively straight, or rather in curves of
large radius, through homogeneous rocks (of course through a succes-
sion of hard and soft beds they have an irregular outline) ; but
on the other hand escarpments wind about, which they should not
do if they were simply old cliffs. Here the saying, “the exception
proves the rule” holds good; for the wonderfully intricate coast-
line of Norway and of other like countries is well known to have
been caused by the sinking of the land, and not by the action of the
sea, the wearing-power of which is as nothing up the deep narrow
winding fjords, so clearly seen to be submerged valleys.
(4.) If escarpments have been formed by the sea, there ought to
be at their foot some resultant of that agent, a beach or other
marine deposit; but this is not the case (except, perhaps, in some
places where masses of Boulder Drift end near the bottom of a
ridge), whatever deposit there is being such as one would look for
from subaérial actions.
(5.) It has been said that any beach which there may once have
been at the foot of an escarpment has perhaps been destroyed
by subaérial denudation wearing back the ridge. To this it has
been answered that such a concession to the power of subaérial
action is really much the same as giving up the question at issue in
their favour ; for if they are powerful enough to do so much they
could surely do more in a longer time.
(6.) Sometimes two escarpments (facing the same way) run
roughly parallel and near together for miles, as those of the Chalk
and Lower Greensand in Surrey and Kent, and those of the Chalk
and the Portland Stone in part of the Isle of Purbeck. To suppose
these formed by the sea implies that there have been two long
parallel ridges of land, each consisting of a separate formation,
divided by a narrow strip of sea, the like of which is not to
be seen now-a-days. Moreover, the sea would have little power
to act in so narrow and sheltered a place, but would be as harm-
1 It would be overburdening this paper with foot-notes were I to acknowledge the
many sources whence some of the following arguments have been in great part
derived; enough to refer the reader to the list of authors given before. I would
gladly have quoted largely from Hutton, Playfair, Scrope, and others, but the paper
would have been much lengthened thereby.
459 Whitaker—On Subaérial Denudation.
less as in the Norwegian fjords, where I have seen the old ice-
scratches run down to (and, perhaps, below) high-water-mark,
uneffaced by the waves. It should be remarked too that in the
above cases the Chalk escarpment is mostly the larger of the two;
whilst according to the marine theory it should clearly be the
smaller, because the inner and therefore the more sheltered.
As far as I know the above arguments have never been thoroughly
answered, much less disproved, by those who hold that the sea has
been the great, if not the only, agent employed in forming escarp-
ments. Until this has been done the marine theory has little
foundation, and indeed is simply a convenient supposition, put
forward to avoid a seeming difficulty, not a theory upheld by sound
inferences and founded on well-established facts.
To these may be added other remarks that have a general bearing
on the discussion, which, I believe, have not been treated of in such
detail as the foregoing, and which refer chiefly to the style of
argument that has been put forward against subaérialists.
(7.) The preservation of old ice-scratchings has often been
brought forward as an argument for the powerlessness of surface-
actions in wearing away rocks; but really it is not a valid one,
for it is not enough that in some places the weather has not acted on
rocks for a very long time, it must be shown that such is the case
in most places; or, in other words, that the weather hardly ever
wears away rocks, not that it does not always do so.
(8.) It has been objected that the subaérial theory needs a vast
time to account for the work done. This is an objection only, not
an argument, and few subaérialists can be afraid of allowing any
quantity of time for the work of those quiet ceaseless actions which
they look on as powerful enough to wear away the hardest rocks. A
late writer, one I believe who is known from his papers on subjects
relating to the connection of Geology and Archeology, has well said,
in a Review of one of Mr. Prestwich’s papers, “the main argument,
as to the process of excavation (of the valleys) and of the length of
time necessarily involved in it will, we are confident, eventually
meet with general acceptance, even if the rising school of geologists
afae may be induced to draw more largely than Mr. Prest-
wich on the cnormous balance of past time which stands in their
favour in the Bank of Nature.” ?
(9.) The occurrence of needles in places far from the sea has
been brought forward as an argument for marine denudation in
those places, and Sir C, Lyell, in the last edition of his ‘‘ Elements
of Géology,”? speaks of the needles of hard Chalk high up the
valley of the Seine as “ evidence of certain escarpments of the Uhalk
1 Got. Mac., Vol. II., p. 26. (1865.)
21865. pp 351-5. As Sir Charles does not now hold that these needles are signs
of the action of the sea (see before, p. 449), it might be thought needless here to
controvert that idea. However, as it is contained in the last edition of his
ee a work constantly referred to by geologists, I have let this paragraph
stand.
Whitaker—On Subaérial Denudation. 458
haying been sea-cliffs.” Now, as will be noticed further on, needles
are formed by atmospheric actions at the top of high cliffs ; indeed,
in nearly all cases they are formed from above, by something that
acts downwards along lines of joint, or fissure; and I can see no
reason why they should not be formed inland, under favourable
circumstances, as well as on the coast; though of course the latter
is one of the most favourable parts for the weather to wear away
rocks, by reason of the carrying away of the débris by the sea.
Moreover the question of the formation of such inland needles in
France by subaérial actions has been worked out by M. Ch. Martins
in a paper noticed before.
(10.) It is however needless to take up the argument in this
way; for before anyone calls forward witnesses of such doubtful
character to prove the marine denudation of a long winding valley
like that of the Seine, he is bound to show that the sea can make
such a valley, or to point to some place where it actually is doing
such work: just as those who say that the sea makes escarpments
are bound to show that it can and does do that sort of work now.
I need hardly say that both these things are impossible. None of
the advocates of marine denudation have given the proofs and
examples needed; and they never will, for the simple reason that
there are none to give.
This is a matter of reasoning simply, not of scientific truth alone,
and it would be well if the rules of the former were a little more
heeded by those whose wish should be to reach the latter, as else
they stand little chance of getting at their object. One of my
colleagues, who is a strong believer in the sea, and nothing but the
sea, has gone so far as to say that “attempts at proving or dis-
proving the soundness of speculations on natural phenomena by a
logical syllogism are scarcely creditable to men of science.”? To such
a statement I must strongly object, for it is clear that the first thing
needed of an argument is that it should be logical. One should not
be surprised, however, at the advocates of the marine formation of
valleys and escarpments looking down on logic (as an unpleasant
test to apply to their arguments) and scorning syllogisms, or in
other words despising true reasoning, unless they follow and “ over-
come those prejudices which contracted views of nature and magnified
opinions of the experience of man may have begotten, prejudices
that are apt to make us shut our eyes against the clearest light of
reason,” and give up one of the most illogical theories that the
ingenuity of geologists ever invented.
(11.) Some folk begin by misrepresenting the followers of Hutton,
and then go on triumphantly to disprove the theory which they
have misunderstood, or sometimes J fear have not taken the trouble
to understand. Thus it has been said that the Huttonians (if that
old name may be used in the limited sense here meant) deny the
power of the sea, and say that rivers, glaciers, rain, and frost have
done everything. Now nothing could be further from the truth ;
1 Grou. Mag., Vol. III. p. 571.
2 Hutton, ‘‘ Theory of the Harth,” vol. ii. p. 367.
454 Walker—New Brachiopoda from Upware, gc.
for they allow that it has been the agent employed in those great
planings-down of solid rocks of which such good evidence is given
by the appearance at the surface of formations that would otherwise
be deep down in the earth, and by the great unconformities shown
by rocks of one age resting on the upturned truncated edges of
others vastly older. In comparison to these huge, and, as they may
be called, ‘‘ continental” denudations and removals of rock, the
present irregularities of the earth’s surface are mere scratches,
though to our eyes grim mountains or sheltered valleys; and until
this is thoroughly understood by geologists there is small hope of
their agreeing in the theory of subaérial denudation."
A steam-hammer can crack a nut certainly; but man does not
commonly use so strong an engine for so small a work, it would be
a waste of power, nut-crackers do just as well: neither does he use
the steam-plough for the tillage of a garden. Is man more careful
of his resources than nature? Should we expect the latter to be
wasteful of her strength and to use her steam-plough, the sea, for
small work when she has plenty of small tools to do it with?
Surely not: nature does not waste power; and rather does great
things with small means, than small things with great means. She
uses the sea to carve out continents and islands; rain and rivers to
cut out hills and valleys: just as the former has deposited wide-
spread masses of rock miles upon miles in thickness, and the latter
here and there some thousand feet of fresh-water beds.
TV.—.On some NEw TEREBRATULIDE FROM UPWARE.
By J. F. Watxer, B.A., F.G.S., ete.
(PLATE XIX.)
N my paper published in the July Number of this Macazinz I
gave a list of the Terebratulide from the Upware deposit; since
then I have further examined them, especially with regard to the
shell I named Zerebrirostra neocomiensis. ‘There are clearly certain
well-marked differences between the Upware species and that fossil.
The shell I called T. hippopus also proves to be a new species.
Some of the specimens of the small variety of T. oblonga closely
correspond with 7. Fittoni of Meyer, which was described in the
first volume of this Magazine; it was found at Godalming in
Surrey. I have also some specimens of 7’. Dutempleana from the
Upware bed; and I have no doubt the affinities of that shell with
T. prelonga (a species not uncommon at Upware) will be able to be
determined. (See Cretaceous Brachiopoda, by T. Davidson, page 59).
Waldheimia Davidsonii, sp. u., Figs. 4a.-d. — Shell elongate
ovate, surface finely striated, striz dichotomous at various distances
from the hinge, and marked by concentric slightly raised lines of
growth. Beak rather long, nearly straight, foramen medium-sized,
1 Professor Ramsay has noticed the great thickness of solid rock that must have
been denuded in Wales (Mem. Geol. Surv. vol. i. p. 297, and plates. 4, 5, 1846; and
vol. ili, p. 236, and pl. 28, 1866). I believe that the former of these was the first
attempt at showing the vast amount of denudation that has taken place.
GRDeWilde del.et lita M &N Hanhart. imp.
NEW SPECIES OF BRACHIOPODA FROM
UPWARE CAMBRIDGESHIRE &¢
Walker—New Brachiopoda from Upware, gc. 455
deltidium large, in two pieces. The dorsal valve is slightly convex,
and scarcely indents the ventral valve. The ventral valve is like-
wise convex, or sub-carinate, and is slightly compressed at the sides.
The loop extends nearly to the front of the dorsal valve. Length
1:Lin. to 1:3in.; width 0-6in. to 0-9in. ; thickness about 0-din.; of
mature specimens.
This species is tolerably abundant in the Lower Greensand
deposit at Upware. I regarded it as a variety of Terebrirostra
neocomiensis, d Orb., and indicated it under that name in my paper
on the Upware deposit; but it appears to differ from that species, as
was pointed out to me by Mr. Davidson, especially in the deltidium
being in two pieces, and in the shorter length of the beak. The
loop is that of a Waldheimia, and, considering the resemblance of
the shell to Terebrirostra neocomiensis, it would seem to confirm
Mr. Davidson’s supposition of the probable identity of Waldheimia
and Terebrirostra. W. Davidsonii varies somewhat in form, bemg
sometimes longer and narrower, sometimes broader and flatter, than
the specimens figured.
I have named this fossil in honour of T. Davidson, Esq., F.R.S.
Waldheimia Woodwardii, sp. n., Figs. 8a.—d.— Shell rather
elongate ovate, external surface smooth, ventral valve strongly
keeled. Keel much arched towards the beak, the sides nearly flat,
so that a transverse section of the shell forms a nearly equilateral
triangle. Beak short, slightly recurved, truncated by a rather large
foramen. Dorsal valve ovate, rather convex towards the hinge-
margin, and slightly grooved along the centre; indenting the ventral
valves at the front margin. Loop (as indicated by internal cast,
Fig. 38d) about half the length of the dorsal valve Dimensions :
length 1:4in.; width 0-9in.; greatest depth 0-8 inches.
This shell, which is very rare, occurs at Upware. I referred it to
T. hippopus, Roemer, in my paper on that deposit. It appears to
approach most closely to T. hippopus of any of the Cretaceous species ;
but differs in its more elongated form, in the triangular shape of its
transverse section, and in having the frontal portion of the dorsal
valve nearly flat, so that the ventral valve is very slightly indented.
Of Jurassic forms of Terebratula, this species approaches nearest to
T. resupinata and T. carinata.
I have named this remarkable species after the late Dr. S. P.
Woodward, to whom science is indebted for many valuable obser-
vations in connection with the Brachiopoda.
Terebratula Dallasii, sp. n., Figs. 1 and 2.—Shell ovate, length
exceeding the width, much inflated, often globose, smooth exter-
nally, marked with a few lines of growth, especially on the frontal
surface. Beak short, rather straight, truncated by a large foramen,
partly margined by a rather wide deltidium, formed of one piece,
and generally diminished by the encroachment of the hinge margin.
Loop extending nearly half the length of the dorsal valve. Dimen-
sions of a globose specimen (Fig. 1): length 1:2in.; width 0-9in. ;
depth 0:95in. ; of an angular form (Fig. 2): length 1-lin.; width
0-8in.; depth (at the front margin) 1 inch.
456 Morris—Ferruginous Sands of Buckinghamshire.
This species occurs in the Upware deposit, and also in the con-
glomerate bed near Potton; in the former the specimens are cal-
careous, in the latter ferruginous. Calcareous casts of the interior
also occur at Upware.
By its remarkable form, this species is easily distinguished from
all other Cretaceous Terebratule.
I have great pleasure in naming this fossil after my friend W. S.
Dallas, Hsq., F.L.S., etc,
DESCRIPTION OF PLATE XIX.
Fig. 1. Terebratula Dallasii from near Potton.
2 Lerebratula Dallasii, from near Upware.
la & 2a. Dorsal aspect of shell.
14 & 26, Side view of same.
le & 2¢. View of anterior margin of valves.
3. Waldheimia Woodwardii, from near Upware.
3a. Dorsal aspect of shell.
3b. Side-view of same.
8¢. View of anterior margin of valves.
3d. Ditto, cast of interior, from the same place.
4. Waldheimia Dividsonii, from near Upware.
4a & 4c. Dorsal aspect of shell.
46. Side-view of same.
Ad. View of anterior margin of valves.
V.—On tHE Ferrucinous Sanps oF BUCKINGHAMSHIRE, WITH
REMARKS ON THE DISTRIBUTION OF THE EQUIVALENT STRATA.
By J. Morris, F.G.S.
HE coarse ferruginous sands at the base of the Cretaceous
series, in the counties of Bedford and Cambridge, have of late
years attracted considerable notice, not only as sources of iron ore,
but also of phosphatic matter. To these deposits the attention of
geologists has been directed, and among other valuable papers,
may be mentioned some by Messrs. Seeley and Walker,’ who have
treated of their general physical characters, and also of their in-
teresting fossil contents. It may be useful to some of the readers
of the GronocicaL Macazinr, who are interested in tracing out the
range of this deposit, and the peculiar conditions under which it
was accumulated in some parts of the area, to point out briefly its
characters and contents in the adjoining county of Buckingham ;
4.¢e., around Aylesbury*: more especially so, as these sands have been
considered to be partly equivalent in time, or the marine conditions
of the Wealden and Purbeck strata.
These beds vary slightly in mineral character in the district to be
noticed ; the most marked or predominant feature being, however,
1 Ann. and Mag. Nat. Hist., Aug., 1866; July, 1867. Guroz. Maa., Vol. IV.
p- 199. Ann. and Mag. Nat. Hist., July, Nov., 1866; Aug, 1867. Brodie, Guo.
Mae., Vol. III. p. 153. Walker, Brit. Assoc. Dundee, Sept., 1867. See also
Original Article IV. in this number of the Geox. Maa. .
2 A part of this district being uncovered by Drift or Boulder-clay, good sections of
the Lower Greensand, Purbeck, Portland, and Kimmeridge clay may be seen, and a
little to the north, in the railway cutting, the Oxford clay. See ‘‘ General Sketch of
the Geology of Hartwell,’ London University Magazine, June, 1856, p. 102.
Morris—Ferruginous Sands of Buckinghamshire. 4057
a more or less thick deposit of coarse ferruginous sand, with inter-
calated bands, or irregular concretions of ironstone, for the ex-
traction of which this bed has been extensively worked in many
places, and its general characters and contents more fully made
known.
It was from these sands, in the neighbourhood of Leighton, that
the specimens of Cycadites Yatesii, described by Mr. Carruthers,"
were obtained, associated with coniferous wood; but no other fossils
have been met with to my knowledge, although near there—at
Linslade—casts of Nucula and other marine shells were found. In
a south-westerly direction these beds are not so thick, and are seen
capping the hill-tops, the intervening portions having been removed
by denudation. Thus, around Aylesbury, at Hartwell and Stone,
these sands overlie the Purbeck and Portland beds, but in a southerly
direction have been removed over a considerable area, until their
equivalents are again seen at the surface near Bishopstone, beyond
which they are covered by the Gault and Upper Greensand ; these
again dip under the Chalk strata of the Chiltern Hills, which form
a portion of the fine chalk escarpment overlooking the country to
the north. The Upper Chalk is again covered by the Tertiary
strata, which in some places, as at Hampden, is a hard sandstone,
and silicious flinty conglomerate, identical with the so-called ‘‘ Druid
Sandstone,” or ‘‘Sarsen-stone,’—very durable, and which has been
worked for building and road-stone, and largely used for the foot-
ways at Aylesbury, and in Hartwell grounds.’
Dr. Fitton, in his able memoir, “ On the strata below the Chalk,’
carefully described the district around Hartwell, and gave a full
account of the sections then exposed, since which time (1827) some
sections have been enlarged, and other pits opened, so that a few
additional facts have been obtained, but which do not invalidate the
conclusions arrived at by Dr. Fitton; thus, for example, the ferru-
ginous or Lower Greensand has been found to contain fossils, not
known at that time, from this locality. It is to these sands that this
brief notice is more especially directed, reserving for a future time
some remarks on the Purbeck and Portland beds of this district.
These sands and associated beds are well seen in four or five pits
around Hartwell, as well as along the Dinton road, and at the brick
works between that village and Haddenham, and also further west,
at Thame, Hazeley, and Brill. At the red sand pit, not far from the
Bugle Inn, an opening exposed about six feet of the sands overlying
a partly irregular surface of one of the Portland beds. The sands
are coarse, highly ferruginous, containing ochreous concretions, and
many quartz pebbles (which at one time were specially collected), as
well as many more or less rounded but large pebbles, consisting
of different materials, as quartzite, lydian stone, and others, evidently
originally derived from the older rocks. At the base of these sands,
1 Grou. Maa., Vol. IV. p. 199. Pl. IX.
2 Blocks of this stone, known as Hampden stone, have been extracted five or six
feet in length, and used as ornamental stones, or rude pillars, as at Hartwell Park.
3 Geol. Trans., 2 ser., vol. 4, p. 285 e¢ seg. See also Aides Hartwelliana.
458 Morris—Ferruginous Sands of Buckinghamshire.
but not in situ, are blocks of compact brown sandstone, containing
casts of Unio (U. Gaulteri?) Cyrena, Paludina, and traces of plants.
The sands themselves contain impressions of shells as Lima undata
Desh., Pecten distriatus, P. Cottaldinus? Exogyra sinuata, Rhynchonella
antidichotoma, Ostrea macroptera, Spondylus, Teredo and Pholas (Pho-
ladidea)' Cornuelliana. Many Foraminifera, Rotalina, etc., some
small corals and Bryozoa, and large pieces of coniferous wood, in
some decomposed portions of which casts of a boring shell were
observed ; no phosphatic nodules were noticed, or fossils derived
from other strata, except the Freshwater sandstone above noticed.
These sands may be traced in part of Hartwell Park. At Lock’s
pit,” on the Thame road, just beyond the Hartwell grounds, a
section from five to twelve feet deep, presented, in the lower part,
fawn-coloured sands, with thin darker, sometimes carbonaceous,
layers, very irregular, overlain by sandy clays and impure fuller’s
earth and coarse sands above, but no fossils. Further on the road,
at the white sand-pit, a better section was exposed, consisting, in
descending order, of coarse ferruginous sand, sandy clay, fuller’s
earth, shaley clay and grey sand, large lenticular, but not continuous,
masses of pisolitic hydrated oxide of iron, reposng on an uneven
surface of white sand, containing large irregular hard siliceous
concretions, assuming very grotesque forms called ‘ bowel-stones,’
this sand is about 20 feet thick.’
Beyond Stone Church, opposite the Vicarage, and near the wind-
mill, large excavations have been made for some years past, showing
the coarse ferruginous sands and associated beds, but not so definitely
as at the white sand-pit ;* and extensive openings on the right of
the road from Stone to Hythorpe, exhibit similar white ferruginous
and coarse sands. Some years since, during the progress of the
excavations in the sand-pit, and along the road opposite the vicarage,
human remains and various implements were found, affording evi-
dence that this spot was used as a burial-ground during the Roman
1 This appears to be a variety of P. Cornuelliana, d’ Orb, and is probably identical
with the P. Dalasi, Walker; a similar form occurs at Farringdon, and at Seend,
in Wiltshire.
2 Tn going from the ‘ Bugle’ to this section, we first observe the large stone-pit of
Purbeck and Portland beds, uncovered by sands, which only set in as we ascend the
hill towards Stone.
3 These concretions were used as ornaments in the neighbourhood. A large
number may be seen built into the wall of Hartwell Park, as well as fine specimens
of Ammonites giganteus : the wall itself is of Portland stone, from the adjacent quarry,
and the date of building picked out with the Hampden stone. The sand has been
extensively worked, and sent to Birmingham for glass making, the finer and whiter
portions have realized 17. 1s. a ton, and other portions about 8s. to 12s. per ton.
Large globes and prisms of glass, made from this sand, are in the Hartwell Museum.
4 The following section was formerly exposed :—
Coarse sand and pebbles ........ gagooon9ddcencosdoGJaBadABoBaN0000030 4 feet.
Ferruginous sandstone and rock ...........ssseseenscvecscescerevoee 6 inches.
Imperfectly stratified clay (fuller’s earth >) .......csseesseoeee 4 inches,
HertuoiMousisandmeeeesaterescereresereerasseness a uie se dek decemececcis 1 foot.
Grey sendy Clay ts.sorssrcsscts scene tonclcecisseave se sese tence epee aeEe 1 foot.
White and grey sand, wavy and irregular, with carstone and
ITONSLONE ...seessssrerseers aouovetiececeuscthsane@ectocsectledes seroee 8 feet,
Morris—Ferruginous Sands of Buckinghamshire. 459
occupation of Britain. An account of these discoveries was commu-
nicated by Mr. Akerman to the Society of Antiquaries in 1851.
These sands occupy a considerable area on the top of the hill near
Stone, being about one quarter of a mile from north to south, and
about three quarters of a mile from east to west. From their area,
their ready permeability to water (having been estimated to yield
about 40,000 gallons of water per day), and the geological condi-
tions of the underlying strata, they are important as an available
source of water-supply, the capabilities of which for that purpose
were first pointed out by Dr. Millar, F.G.8., in 1854, after the
failure of a well, 500 feet in depth, sunk in the Bucks Asylum
grounds, through the Portland and Kimmeridge beds into the Ox-
ford clay. Acting upon his suggestion, that this body of sand would
always contain a sufficient store of water, the Asylum has since
that time derived its chief supply from this source.’
During some excavations for drainage in the adjacent grounds at
a lower level, and probably corresponding to the base of the sands
at their junction with the Purbeck strata, masses of ferruginous
sandstone with Unio and Paludina were found similar to those in
the red sand-pit. At nearly the same horizon, near Stone Church,
many specimens of Hndogenites erosa were found by the Rev. Mr.
Lowdnes and myself, indicating, as I believe, the former existence of
the Wealden beds over this area, subsequently removed by denuda-
tion previous to or during the deposition of the sands above, and
disproving to some extent the notion that these sands are the
equivalents in time of the Wealden and Purbeck strata.
Having shown that these sands, containing fossils of the Lower
Greensand, and at some points freshwater shells near their base,
sometimes overlie the Purbeck and Portland beds with an indication
of the Wealden, it may be interesting to trace the equivalent strata as
they range to the north-east or south-west of this district, and com-
pare the mineral character in different localities as given by various
authors.”
The sands trend north-westerly from Aylesbury, through Bedford
and Cambridge into Norfolk, where, under the name of ‘ Carstone,”
they underlie the red chalk and cretaceous beds, as is well seen at
Hunstanton. At Potton,? in the former county, many fossils and
phosphatic nodules have been obtained, and at Woburn, in the same
formation, fuller’s earth has long been worked.
At Upware, in Cambridgeshire, these beds have recently been
shown to be fossiliferous, containing many species of Terebratula
1 Special report in reference to the supply of water for the Bucks Lunatic Asylum,
1856, p. 17. Mr. Prestwich remarks “ that the effective permeable beds of the Lower
Greensand are 200 feet thick, that they occupy an area above and below ground of
4,600 square miles, that a mass of only one mile square and one foot thick will hold
more than 60,000,000 gallons of water, and some idea may be then formed of the
magnitude of such an undergrouud reservoir.” —‘‘ Water-bearing Strata,” p. 179.
2 Dr. Fitton, Geol. Trans., Vol. iv. p. 285, e¢ seg. Holloway, Phil. Trans. 1723,
Vol. xxxii. p. 419. Prestwich, Water Bearing Strata, p. 85.
3 Seeley, Ann. and Mag. Nat. Hist., Aug, 1866. Walker, ibid., Aug. 1867. Brodie
Guou. Maa., Vol. III. p. 153.
* Conybeare and Phillips, Outlines, p. 138. Fitton, Geol. Trans., Vol. iv. p. 294.
460 Morris—Ferruginous Sands of Buckinghamshire.
and sponges, some similar to those at Farringdon, and also rolled
specimens derived from older rocks, my friend, Mr. Huddlestone,
F.G.S., has shown me a fine series collected from this bed.!
At Ely and Haddenham these sands rest on the Kimmeridge clay.”
Further northwards, in Lincolnshire, a change takes place in the
mineral character of the beds, presenting somewhat an approximation
to the southern type. Mr. Judd® has described the strata, overlying
probably, the Oxford clay, near Market Rasen and Tealby, to
consist of —
1. Upper ferruginous sands, non-fossiliferous, twenty feet thick.
2. Tealby series, alternate beds of sandy clay and limestone, with
many fossils, forty to fifty feet.
3. Lower sand and sandstone, with few fossils, thirty to forty feet.
A somewhat similar arranyement of the strata below the Red
Chalk in Lincolnshire, was proposed by Mr. Conybeare, in 1822, viz.
1. Quartzose, ferruginous, pebbly sand, from eight to ten yards.
2. Calcareous clay, containing beds and concretions of Oolitic lime-
stone, from twelve to fourteen yards.
3. Granular quartzose sandstone and sand, varying from dark-brown
to light-grey, and containing shells, considerably thicker
than the two former beds.
These beds rest on strata of argillaceous shale, which appear to
belong, in part at least, to the Oxford clay.*
Crossing the Humber the equivalents of these beds pass under
the Wolds, and again reappear at the well-known section of Speeton,
long ago described by Professor Phillips, in which the mineral
character again differs from that of Lincolnshire and Bedfordshire.
This is the most northerly extension of the Lower Cretaceous rocks,
which here are considered to overlie the Kimmeridge clay.
In a westerly and south-west direction from Aylesbury the Lower
Greensand may be traced, but not always continuous, at Brill®
1 Walker, Grou. Mac., Vol. IV. p. 309.
2 Sedgwick, Lecture on the strata near Cambridge, Dec., 1861, p. 21.
8 Quart. Journ. Geol. Soc. vol. xxiii. p. 248. In the year 1859, during a visit to
Mr. Morel, at Bayons Manor, I traced out, with Mr. T. J. Smith, F.G.S., of Hull,
the characters of the Lower-green Sand around Tealby, from Hainham to Caistor,
and pointed out the existence of the pisolitic iron ore then unworked at Walesby,
and arrived at the conclusion that these beds and their fossils, as well as those at
Speeton, should be carefully compared with the Histhon and Hilsconglomerat of N.
Germany (Hanover), and not with the Portland, as suggested by a geologist. I col-
lected many fossils, such as the large Pecten, Ancyloceras, Trigonia, Belemnites, etc ,
some of which are now in the British Museum. A general sketch of the geology of
the locality mentioned was given in the introductory lecture that I had the pleasnre
of giving at the opening of the Tealby Institute (Nov. 29, 1859), established by the
late Tennyson D’Eyncourt, Esq. I subsequently examined, in company with Mr.
Prestwich and Mr. S. Sharp, the district around Spilsby and Horncastle, etc., and
found in the sands at the former place specimens of Coniferous wood with Teredo
borings and also phosphatic nodules. Mr. R. Godwin Austen considered the Speeton
clay to be the representative of the Hilsthon (Proc. Geol. Soc. vol. iy. p. 196). See
also Roemer, Die Versteinerungen des Norddeutschen Kreidegebirges, Hanover,
1840.
4 Outlines of Geology, 1822, p. 164.
5 Fitton, Geol. Trans., Vol. iv. p. 280. Estuarine sands with Paludina, Brodie,
Quart. Journ. Geol. Soc., Vol. xxii, p. 198.
Morris—Ferruginous Sands of Buckinghamshire. 461
(where fresh-water shells are found), Thame, and Shotover Hill; a
good section is here seen with the intercalated ochre beds, and at
this latter locality fresh-water shells, as Unio, Paludina, etc., have
been observed in the sands overlying the Portland by Mr. Jelly,
Mr. Strickland, and Professor Phillips.‘ The rich fossiliferous sands
of this series, overlying the Coral rag, are well known at Farring-
don,? and they may be seen at Swindon, above the Purbeck, Locks-
well Heath (rich in fossils) above the Calcareous Grit, at Roade,
with Nucula, and at Seend, overlying the Kimmeridge clay; at the
latter place the ferruginous sandy beds have been worked for iron
ore, they contain fossils, and at one spot the cavities, formed in the
Kimmeridge clay below by the boring molluscs of the period (Lower
Greensand), are well seen, proving that the Kimmeridge beds must
have formed ihe sea-bottom during their accumulation.
Mr. Conybeare, in 1822, describes the beds at Seend as being a
pudding-stone, composed of rounded quartz, whose cement is silicious
with a calyx of iron, containing ore formerly in much request for
the furnace and the forge; and forming the materials whence the
ancient Britons wrought their Quernstones.* Further south the
sands are but faintly seen in the vale of Wardour, overlying the
Purbeck and Portland beds, and their equivalents are again recog-
nised at Ridgway, near Weymouth.
These beds may be traced eastward from Weymouth, at many
points, as at Lulworth, Worbarrow, and Swanage bays, and on to
the Isle of Wight, separating the Wealden and Purbeck from the
middle cretaceous rocks. The fine sections of the Isle of Wight,
rich as they are in fossils, present, however, different mineral cha-
racters from their more eastern and northern representatives, consist-
ing mostly of coarse and fine sands, shales and clays, and little
limestone, in fact chiefly arenaceous and argillaceous deposits.
Around the wealden of Kent, Surrey, and Sussex, the Lower Green-
sand strata are extensively developed, but vary in their mineral
characters; thus from Reigate, westward, although presenting a
triple subdivision, the beds are chiefly arenaceous and argillaceous;
between Reigate and Bletchingley the intercalated mass of fullers
earth occurs,’ which, according to Mr. Meyer,’ belongs to the Upper
or Folkstone series, and is almost on a level with the Bargate-stone
of Godalming, the latter, according to Dr. Fitton, being the equiva-
lent of the calcareous beds of Kent. From about this point the
limestones known as the Kentish Rag®set in, and are more or
less worked, throughout their continuous range, to Hythe, as at
eine Geol. Trans., Vol. iv. p. 275. Phillips, Journ. Geol. Soc., Vol. xiv.
F 2 R. A. Godwin Austen, Quart. Journ. Geol. Soe., Vol. vi. p. 464. D. Sharpe,
ibid., Vol. x. p. 176.
3 Outlines, p. 142.
4 Conybeare and Phillips, Outlines, 1822, page 152; Fitton, Geol. Trans. vol. iv.
. 141.
P 5 See Grou. Mac. 1866. Vol. ITI. p. 15.
6 This valuable building stone was extensively used in early Ecclesiastical archi-
tecture, and is now largely worked for the building of most of the modern London
churches and for other purposes,
462 Morris—Ferruginous Sands of Buckinghamshire.
Seven Oaks, Maidstone,! Boughton, and near Ashford, etc. The
coast line from Hythe to beyond Folkstone harbour, exposing, as is
well known, a fine section of the Lower Green sand series.”
From the foregoing brief remarks it will be seen that the Lower
Green-sand strata vary in their mineral characters, when traced over
the British area, thus the limestones of the eastern part of the
Wealden districts are wanting in the western part, as well as in the
Isle of Wight, where arenaceous and argillaceous beds predominate.
On this point Mr. Meyer and Dr. Fitton have made some sug-
gestive and valuable observations. So also on tracing them from
Dorset to Yorkshire, they chiefly consist of ferruginous sands, and
sandstones, which in Lincolnshire are intercalated by sandy calca-
reous beds, called ‘ greystone,’ and still further north at Speeton, are
represented by argillaceous strata. Further, it may be observed
with regard to their position that, in Southern England, these beds
always directly overlie the Wealden beds, whilst as they trend from
Dorset to Yorkshire, they are found lying upon either the Purbeck,
Portland, Kimmeridge, Cale grit, Coral rag, or Oxford clay, some of
which from the evidence afforded by the boring mollusca, must have
remained for a period uncovered by the now overlying sands.’
That a certain amount of denudation took place prior to the deposi-
tion of the Lower Green-sand, in the northern area, is, I think,
evident,® but that the Purbeck and Portland strata ever extended far
beyond their present limits is not so probable, as they may have
thinned out in that direction, a point to which I may again refer,
when treating of these formations as they occur in Bucks.
NOTICES OF MEMOTRS-
Se
British ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE.
Dunprx, September 5th, 1867.—List of Papers read before the
Geological Section. (Section C.) President, Archibald Geikie,
F.R.S., ete.
Dr. Robert Chambers—Notice of an “ Esker” at St. Fort.
1 From the quarries of this stone belonging to Mr. Bensted of Maidstone, the fine
specimen of Igwanodon Mantelli, now in the British Museum, was obtained in 1834.
2 Fitton, Geol. Trans. vol. iv. plate 8.
3 ©. J. A. Meyer, ‘On the Correlation of the Cretaceous Rocks of the South-east
and West of England,’ Grou. Mag. vol. iii, Jan, 1866; Fitton, ‘‘ Comparative re-
marks on the Sections below the Chalk at Hythe, Kent, and Atherfield, Isle of
Wight, Geol. Journ. vol. i. p. 179, May, 1844. Dr. Fitton shews that the prominent
points of difference between the sections of the Kentish coast and the Isle of Wight,
are considerable variation in mineral composition,—the almost total absence of Lime-
stone at Atherfield, and the greater thickness of the Lower Green-sand at this latter
place (by 346 feet) than at Hythe.
4 Where the “Tourtia,” or part equivalent of Lower Green-sand, in Belgium,
overlies the denuded surface of the contorted beds of Paleozoic limestone, numerous
borings of mollusca may be seen, as at Montigny-sur-roc and other places.
5 The former existence of the Upper Wealden strata, in the interior of England, is
rendered probable by the erosion of the Purbeck beds, in many places, where the
Lower Green-sand comes in contact with them. Fitton, Geol. Trans., vol. 4, p. 326.
See also Mr. Walker, An. Mag. Nat. Hist., August, 1867.
Geological Papers read before the British Association, Dundee. 463
D. Milne Home—On the Old Sea Cliffs and Submarine Banks of the
Frith of Forth.
Dr. J. Bryce—Account of Recent Researches into the Age of the
Arran Granites.
B. A. Wiinsch—On some Carboniferous Fossil Trees, embedded in
Trappean Ash, in the Isle of Arran.
Professor Harkness and Dr. H. A. Nicholson—On the Coniston
Group of the Lake District.
Dr. H. A. Nicholson—On the Graptolites of the Skiddaw Slates.
Dr. H. A. Nicholson—On the Nature and Systematic Position of the
Graptolitide.
R. H. Scott—Preliminary Report of the Committee for the Hxplora-
tion of the Plant Beds of North Greenland.
J. Wyatt—On the Gradual Alteration of the Coast Line in Norfolk.
George Maw—On the Cambrian Rocks of Llanberis, with reference
to a break in the Conformable Succession of the Lower Beds.
Dr. Oldham—On the Geology of India.
The President—An Account of the Progress of the Geological
Survey of Scotland.
H. Woodward—Third Report on Fossil Crustacea.
F. M. Burton—On the Lower Lias, and traces of an ancient Rheetic
Shore in Lincolnshire.
J. H. Taylor—On the Norfolk Chalk-marl.
H. §. Ellis—On the Mammalian Remains from the Submerged
Forest in Barnstaple Bay, Devonshire.
W. Pengelly—Third Report of the Committee for the Exploration of
Kent’s Cavern, Devonshire.
Professor Ansted—On the Conversion of Stratified Rock into Granite
in the north of Corsica.
Dr. Julius Schvarez—On the Internal Heat of the Earth.
Dr. C. Le Neve Foster—On the Preseberg Iron Mines, Sweden.
F. Gordon Davis—On the Calamine Deposits of Sardinia.
Dr. C. Collingwood—On the Geology of the North of Formosa, and
of the adjacent Islands.
—QOn some sources of Coal in the Eastern Hemi-
sphere.
—Notes on the Geological Features of the Sarawak
River.
W. Carruthers—Enumeration of British Graptolites.
HK. Hull—On the Structure of the Pendle Range, Lancashire, as
illustrating the South-easterly attenuation of the Carboniferous
Sedimentary Rocks of the North of England.
W. 8S. Mitchell—Second Report on the Alum-Bay Leaf-bed.
E. Hull—Observations on the Relative Geological Ages of the
principal Physical Features of the Carboniferous District of
Lancashire.
W. Carruthers —On British Fossil Cycadex.
———On Calamitez and Fossil Equisetacee.
Professor Charles Martins—On the Ancient Glacier of the Valley of
Argelez, in the Pyrenees (read in French by the Author.)
464 Geological Papers read before the British Association, Dundee.
C. W. Peach—On new Fossil Fishes from Caithness and Sutherland.
Hi. Ray Lankester—On some new Cephalaspidean Fishes.
J. F. Walker—On a new Phosphatic Deposit.
Captain F. Brome—Notice of recent discoveries in Caves of
Gibraltar, communicated by G. Busk, F.R.S.
Professor Ansted—On the Lagoons of Hastern Corsica.
Rev. W. H. Crosskey—Notes on the relation of the Glacial Shell
Beds of the Carse of Gowrie to those of the West of Scotland.
John Plant—-On the Geology and Fossils of the Lingula Flags,
at Upper Maddach. North Wales.
Rev. J. Gunn—On Tertiary and Quaternary Deposits in the Eastern
Counties, with reference to periodic oscillations of level and
climate.
Mr. James Thomson exhibited a large series of sections of Corals
from the Carboniferous Limestone, etc., prepared to illustrate
Dr. P. Martin Duncan’s Monograph on British Fossil Corals, for
the Palzsontographical Society.
Mr. R. Slimon’s collection of Upper Silurian Crustacea, from Lesma-
hagow, in Lanarkshire, were exhibited, and Mr. Woodward
called attention to some of the new forms.
REV LeEws.-
Ficurrs or Cxaractreristic British Fosstns: wita Dkzs-
cRIPTIVE Remarks. By Wiuiiam Heirer Baity, F.L.S.,
F.G.8., Acting Panm#ontotogist to H.M. Gxo.ocicaL SuRVEY
or Irenanp, etc., etc. Part J., Plates 1-10, Cambrian and Lower
Silurian. 8vo. pp. 54. 1867. London: J. van Voorst.
HIRTY-SEVEN years ago Samuel Woodward (Author of “ An
Outline of the Geology of Norfolk’) published his ‘‘ Synoptical
Table of British Organic Remains,” being the first attempt in this
country to furnish a systematically and stratigraphically arranged
list of British fossils since the Ichnographia of Lhwyd in 1699.
Thirteen years later (1848) the progress of geological studies
necessitated a new edition, but Mr. Woodward being dead, Professor
Morris brought out the first edition of his “Catalogue of British
Fossils,” a work which has justly maintained the first place in all
geological libraries. The second edition appeared in 1854. We are
glad to learn from the author that the third edition is now in pre-
paration, and shall be still more so to announce it as ‘“‘now ready.”
Only those who have the work of arranging a geological collec-
tion can fully estimate the value of a reference catalogue. And this
need increases with the size and varied nature of the collection to be
named. The book before us does not chiefly aim at supplying the
wants of the scientific worker and museum curator, but it is intended
rather to assist geological students, and others, who, from their limited
knowledge of paleontology, require to have figures of the various
fossils placed before them, as well as their names and references, in
order to enable them to identify their specimens. When it is borne
Baily—Lfigures of British Fossils. 460
in mind how many geological students there are living scattered
through the length and breadth of the land, to whom access to a
geological library is for ever denied, it is easily to be understood
what a boon such a work as a well illustrated catalogue of British
Fossils must be to them, even if it takes in only the characteristic
British species. Of course it will occupy some time for the comple-
tion of such a work as this which Mr. Baily has undertaken ; but
the present number is an earnest of the future, and promises well
for those who have subscribed to so good an object.
The ten plates which accompany this number are carefully drawn
on stone by Mr. Baily, some from the original fossils, some from the
memoirs of the Geological Survey, the Palseontographical Society’s
Monographs, and other sources.
We would counsel the adoption of finer grained lithographic
stones in illustrating the future numbers of this work, as the merit of
the artist’s style is occasionally injured by the want of sharpness in
some of the figures.
The woodcuts, interspersed through the pages of descriptive
remarks, are well executed, and add much to the interest of the text.
We wish Mr. Baily all the success he so well deserves in the
carrying out of this important work.
Iv lhi=S OSA S) Jaap), ASSOC naa Dab leis
i
British ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE.
ADDRESS TO THE GEOLOGICAL SECTION
By ARcHIBALD GEIKIE, F.R.S., &c.
Director of the Geological Survey of Scotland, Erenden of Section C. Dundee,
September Sth, 1857.
After some introductory remarks, the President said :—
In that combination of features which renders the British Islands
so remarkable an epitome of the geology of the globe, not the least
important item, as it seems to me, is the development of igneous
rocks which we possess. From the massive feldspathic lavas and
ashes of the Lower Silurian rocks, up to the great basaltic plateaux
of Miocene age, most of our geological formations contain some-
where evidences of contemporaneous volcanic activity. And these
traces, instead of being confined to limited districts, are found often
to range for many miles through groups of hills and wide stretches
of lowland.
This copious development of volcanic rocks cannot but present
many facilities for the study of volcanic phenomena. ‘The investi-
gation may be approached from a number of different sides, resolv-
ing itself in this way into several distinct lines of research. 'Thus,
these igneous masses may be studied stratigraphically with the
proofs of their having been successively erupted at the surface during
the growth of the various formations among which they occur.
Hence, on the one hand, we may obtain much curious insight into
the geological history of a district, while, on the other, by taking
VOL. 1V.—NO. XL, 30
466 Geikie— Volcanic Rocks of Great Britain.
a broader view of the whole subject, we may to some extent trace
the progress of volcanic action over the whole country. Again, the
rocks may be examined, irrespective of the formations to which they
belong, as repositories of data respecting the phenomena of volcanos.
They may be studied as chemical or mineralogical compounds, and
compared or contrasted with the products of modern volcanos.
When, moreover, we reflect how many of these igneous masses must
have consolidated on the floor of the sea, and how rare are the
opportunities of investigating the progress of an active submarine
volcano, we perceive that an attentive study of our own volcanic
rocks may even elucidate some of the less observable features of
modern volcanic action. Or these igneous masses may be examined
with the view of ascertaining how far volcanic activity may influence
submarine life. Thus, in some of our geological systems, among
the Silurian rocks of Wales, for example, or the Carboniferous lime-
stone group of Fife and the Lothians, many instructive sections
occur where an abundant series of crinoids, corals, brachiopods, and
other organisms, is gradually or suddenly enveloped in a mass of
tuff. Other instances likewise abound in which a suite of fossils
may be found slowly struggling through the upper part of a bed of
tuff, until the ashy sediment dies away, and the fossils gather to-
gether into a bed of limestone. Hven among the coal seams and
ironstones of Scotland such intimate relations to contemporaneous
volcanic action may be traced.
I purpose, at this time, to point out, by one or more illustrations
from each of our geological formations wherein volcanic rocks occur,
how varied and long-continued has been the progress of volcanic
action in these islands. I shall offer, in conclusion, some sugges-
tions as to phases of the subject which seem to me deserving of more
special study than has yet been accorded to them.
Lower Silurian —The oldest recognisable volcanic rocks in this
country belong to the lower Silurian period. They are best dis-
played in North Wales, where, as was shown long ago by Sir
Roderick Murchison, they rise into conspicuous ranges of hills.
Two principal epochs of eruption have been detected by Professor
Ramsay and his colleagues of the Geological Survey. One of these
occurred during the deposition of the Llandeilo rocks, and is indi-
cated by the igneous rocks of Aran Mowddwy, Cader Idris, Arenig,
‘and Moelwyn; the other is marked by those of the Snowdon dis-
trict, which lie among the Bala beds. These volcanic rocks consist
partly of massive sheets of felstone, varying in texture and colour,
and partly of thick accumulations of tuff or ash. The former are
true lava flows, the latter point to frequent showers of volcanic dust,
and to the settling of such dust and stones on the sea bottom, where
they mingled with the ordinary sediment, and with shells, corals,
and other organisms. Some of these ashy deposits attain a great
thickness. Thus, at Cader Idris, “they are about 2,500 feet thick,
the accumulated result of many eruptions.” Northwards this mass
thins entirely away, and the ordinary sedimentary strata ‘take its
place. Equally local are the massive beds of felstone which repre-
Geikie—Volcanic Rocks of Great Britain. 467
sent the submarine lava flows of the time. Sometimes they still
preserve the slaggy vesicular character which marked their surface
when the melted rock was in a state of motion along the sea bottom.
By this and other evidence of a like tendency we learn the existence
and position of true submarine volcanos during the lower Silurian
period in Wales.
Northwards, in the Lake District, Professor Sedgwick has found
similar proofs of volcanic action among the lower Silurian rocks of
that region, and those rocks are now being worked out in detail by
Mr. Aveline and his colleagues of the Geological Survey.
No very distinct traces of contemporaneous volcanic activity have
yet been detected among rocks of this age in Scotland.
Among the lower Silurian rocks of the south-east of Ireland beds
of ash and felstone are interstratified, resembling in general character
and mode of occurrence those of Wales, but on a much smaller scale.
It has been observed that the Silurian fossils of that region occur
only in the upper part of the series in the neighbourhood of the trap
rocks and calcareous bands.?
Upper Silurian —In Wales voleanic action does not appear to
have outlasted the lower Silurian period, but in the south-west of
Ireland, among the headlands of Kerry, massive sheets of ash are
intercalated in grits and slates, which from their fossils have been
assigned to the age of the Wenlock series.*
Old Red Sandstone—The Old Red Sandstone of the southern half
of Scotland abounds in igneous rocks, from the base of the series to
the top. In its lower band lie the chains of the Sidlaw and Ochil
Hills, and many detached masses scattered over the lowlands along
the southern flank of the Grampians. These are composed of differ-
ent felstones and porphyrites, with interbedded sheets of tuff, trap-
pean conglomerate, and sandstone, stretching in the Ochil and
Sidlaw range for sixty or seventy miles, and rising here and there
to heights of 2,000 feet above the level of the sea. This group of
hills contains some of the thickest masses of trappean rock in the
country. In what seems to be a middle portion of the formation
comes the group of the Pentland Hills, consisting of long massive
beds of trap, like the different varieties in the Ochils, with intercala-
tions of tuff, conglomerate, and sandstone,'the whole reaching a,
thickness of fully 5,000 feet.*
In Ireland, also, the Old Red Sandstone furnishes evidence of
active volcanic vents. Among the picturesque glens and cliffs of the
‘See Murchison, “Siluria,” p, 83. Ramsay, Descriptive Catalogue of Rock
Specimens in Jermyn Street Museum, 3rd Kdit., p. 8. Mem. Geological Survey,
vol. lil. p. 21 et passim.
Jukes, Manual, p. 454. See also Memoirs of Geol. Surv. Ireland, Explan. to
Sheets 102, 111, 147, 167.
3 Mem. Geol. Sury., Ireland. Explanations to Sheet 160, etc., p. 21.
4 In the Upper Old Red Sandstone of Scotland proofs of volcanic activity remain
to be gathered. The chain of the Pentland Hills which I formerly regarded as
belonging to the upper member of the formation, I have since found to be covered
unconformably by it, while the chain of the Campsie, Kilpatrick, and Renfrewshire
Hills seems to belong wholly, or at least in great measure, to the lower part of the
Carboniferous series,
468 Greikte—Volcanic Rocks of Great Britain.
county of Kerry, numerous bands of ash—one of them reaching a
thickness of from 500 to 600 feet—stretch from mountain to moun-
tain under many hundred feet of overlying sandstones and slates.’
Nor are traces of volcanic activity wanting in England during the
same great geological period. In Cornwall and South Devon, Sir
Henry De la Beche recognised frequent proofs of contemporaneous
igneous action among the limestones and slates of the middle
Devonian series, and thence through the Upper Devonian into the
lower part of the Carboniferous group. These consist in frequent
bands of trappean ash and of crystalline amygdaloidal and vesicular
greenstone or other trap rock. The ash passes by insensible degrees
into the ordinary sedimentary strata of the series. Sometimes
it contains fossils, and in certain places it becomes so calcareous, and
so interlaced with bands of limestone, as to have been quarried for
lime. The compact trap rocks associated with the ash bear evidence
of their contemporaneous origin in their frequently cellular and
pumiceous character.’
Carboniferous.—The base of the Carboniferous series in Cornwall
and South Devon is marked by the occurrence in it of sheets of
trappean ash and of crystalline amygdaloidal greenstone, similar |
to the igneous masses among the neighbouring Devonian rocks.
The ash is sometimes coarse and full of fragments of cellular trap, as
in the conspicuous hill of Brent Tor. In describing the rocks of
that locality, Sir Henry De la Beche pointed out the remarkable
resemblance of the Brent Tor to a volcano, and the probability that
the ash and greenstone were erupted over the sea bottom, where
they became interstratified with the ordinary marine sediments.’
In the centre of England the well-known toad-stones of Derby-
shire indicate intermittent volcanic activity during the formation of
the Carboniferous Limestone. They consist of three principal beds
of trap, sometimes compact and dark, approaching basalt in texture,
but usually more earthy and highly amygdaloidal. These beds
average each about 60 or 70 feet in thickness, and preserve their
course for many miles between the strata of limestone. Mr. Jukes
has pointed out that each of them is probably the result of not
merely one eruption, but rather consists of different flows proceeding
from distinct vents, and uniting into one sheet along a common
floor.*
Further north the counties of Durham and Northumberland are
traversed for many miles by interpolated sheets of dolerite, of which
the most important is known as the Great Whin Sill. It does
not appear that these masses have yet been investigated in such
detail as to indicate how far they may be actually contemporaneous
with the Carboniferous Limestone series in which they occur.
Passing into Scotland, we find the Carboniferous formation of the
broad midland valley full of the most striking evidences of volcanic
1 Mem. Geol. Sury. Ireland. Explanation to Sheet 184, See also Explanation to
Sheet 153, p. 18.
2 De la Beche, Devon and Cornwall, pp. 51, 70.
3 Ibid., p. 122. * Manual, p. 523.
Geikie— Volcanic Rocks of Great Britain. 469
activity. From the very bottom of the series up to at least the top
of the Carboniferous Limestone group volcanic rocks of many
varieties abound. In the West, great sheets of different porphyrites,
with interbedded tuffs, sandstones, and conglomerates lie in the
lower part of the formation, and, rising in broad masses, bed above
bed, form that conspicuous chain of terraced heights, which stretches
from near Stirling through the range of the Campsie, Kilpatrick, and
Renfrewshire hills, to the banks of the Irvine in Ayrshire, and
thence westwards by the Cumbrae Islands and Bute, to the south of
Arran.! In the eastern districts, instead of such wide-spread sheets
of volcanic rock, the Carboniferous series includes hundreds of
minor patches of tuff, dolerite, basalt, and porphyrite. 'The area of
the Lothians and Fife seems to have been dotted over with innumer-
able little voleanic vents breaking out and then disappearing one
after another during the lapse of the Carboniferous period up to at
least the close of the Carboniferous Limestone.? The very limited
area occupied by the erupted material is often remarkable. A mass
of ash, a hundred feet thick or more, may be found intercalated
between certain strata, yet, at a distance of a mile or two the same
strata may show no trace of any volcanic material. Nowhere is this
feature more wonderfully exhibited than in the coalfield of Dalry in
the northern part of Ayrshire. The black-band ironstone of that
district appears to have been deposited in hollows between mounds
and cones of volcanic tuff, sometimes 600 feet high, round and over
which the later members of the lower Carboniferous formation were
deposited. Hence the shafts of the pits are sometimes sunk for 100
fathoms through the tuff, and at that depth mines are driven hori-
zontally through the volcanic rocks to reach the ironstone beyond.
In other districts the interstratification of beds of ash and sheets of
basalt and dolerite amongst highly fossiliferous limestones and shales
present many points of interest. In this respect the range of the
Linlithgowshire hills is specially deserving of study.
The great Carboniferous Limestone series of Ireland contains
evidence that here and there, at various intervals during its formation,
minor volcanic vents were active on different parts of the sea bottom.
In the county of Limerick masses of trap 1200 and 1800 feet thick,
with well marked ashy interlacings, lie among the limestones.*
Permian.—Among the Permian sandstones of the south-west of
Scotland there occur some interesting proofs of contemporaneous
volcanic action. In Nithsdale, and still more conspicuously in the
centre of the Ayrshire coal-field, these sandstones contain towards
1 The trap-rocks forming these hills are interstratified in their upper portion with
the Carboniferous Limestone. ‘Their base rests sometimes on a set of marls, shales
and cement-stones, and sometimes on a thick group of red sandstones. These strata
contain Carboniferous plants ; even thin coal seams lie among their higher members,
and although the red sandstones have been hitherto generally called Old Red Sand-
stone, it is not unlikely that they may require to be relegated wholly to the lower
portion of the Carboniferous series.
2 See Maclaren’s Fife and the Lothians. Mem. Geol. Survey, Geology of
Neighbourhood of Edinburgh. Trans. Roy. Soc., Edin., Vol. xxii., p. 644.
3 See Mem. Geol. Surv., Ireland. Explan. to Sheets 143, 144, 163, and 154; also
Jukes’ Manual, p. 320.
470 Geikie—Volcanic Rocks of Great Britain.
their base a thick group of dark reddish-brown amygdaloidal por-’
phyrites and tuffs. Connected with these rocks are numerous bosses
of a coarse volcanic agglomerate, which descend vertically through
the coal-measures altering the coal. They are the “necks,” or
orifices, from which was ejected the volcanic material which now
forms a conspicuous range of rising grounds overlying the heart of
the coal-basin of Ayrshire.1
New Red Sandstone—The New Red Sandstone series of Devon-
shire, in the neighbourhood of Hxeter, furnishes clear proofs of
voleanic activity. Sheets of a dark reddish-brown feldspathic rock,
sometimes compact or porphyritic, but usually of scoriaceous
character, are intercalated among the lower parts of the Red Sand-
stone series of that neighbourhood. That these are not intrusive
masses, but belong to the same geological period as the Red Sand-
stones themselves, is shown by the occurrence of fragments from
them in the overlying conglomerates. Sir Henry De la Beche, who
described these igneous rocks many years ago, noticed that the more
compact portions, instead of extending horizontally as beds among
the sedimentary strata, descend vertically through them, as if these
detached parts marked the site of some of the orifices whence the
melted lava was erupted.’
The series of successive volcanic phenomena, which may thus be
traced through the Paleozoic rocks of the British Islands up to the
New Red Sandstone, is now abruptly broken. I am not aware of
any satisfactory proofs of contemporaneous volcanic rocks among
the Secondary rocks of Britain, save in the Red Sandstone of
Devonshire just referred to. Following a suggestion of Professor
Edward Forbes, I formerly regarded the great trappean masses of
Skye, and the other Western Islands, as probably of Oolitic age.
But more recent investigations in Antrim, Mull, and Higg, have
convinced me that in these districts, and probably also in Skye, the
great basaltic plateaux, which form so conspicuous a feature in the
scenery of our north-western sea-board, date from Tertiary times.’
As the importance of these later volcanic phenomena in the general
geology of the country is not, perhaps, adequately understood, I
may be permitted to refer to this part of the subject at somewhat
greater length.
Tertiary.—F rom Antrim northwards through the inner Hebrides
and the Faroe Islands to Iceland there is a broken chain of volcanic
masses, part, and not improbably the whole, of which date from the
Miocene period. In Ireland sheets of dolerite and basalt, in all 500
or 600 feet thick, and some 1200 square miles in extent, repose
directly upon an eroded surface of Chalk. In Mull similar plateaux,
overlaid with masses of porphyrite and trachyte-like rocks, attain a
united thickness of more than 3000 feet, yet at their base they con-
1 See Geikie, Grou. Maa., Vol. I. for June, 1864, p. 22.
2 Sir H. De la Beche, Devon and Cornwall, p. 199. See, also, Conybeare and
Phillips, Geol. England and Wales, p. 294.
3 See E. Forbes, Quart. Journ. Geol. Soc., vol. viii. p. 108; Geikie, Trans. Roy.
Soc., Edin., vol. xxii. p. 649; and Proc. Roy. Soc., Edin., 1866-67.
Geikie— Volcanic Rocks of Great Britain. 471
tain recognisable plants of Miocene species. This vast depth of old
lavas and tuffs pomts to a lengthened continuance of volcanic
activity along the north-western margin of our country—an activity,
however, marked by prolonged periods of repose, as the Scuir of
Higg,' and the coal and shales of Mull, sufficiently prove. For
magnitude, alike in thickness and extent, these Tertiary volcanic
rocks surpass those of any of the other formations in our area. But
I believe that these masses, vast though they be, are by no means
the only, if they are indeed the chief, relics of Tertiary volcanic
action in Britain.
If, starting from the basaltic plateaux of the north of Ireland or of
the inner Hebrides, we advance towards the south-east, we soon
observe that an endless number of trap dykes, striking from these
plateaux, extends in a south-easterly direction athwart our island.
The south-western half of Scotland and the northern parts of
England, are, so to speak, ribbed across with thousands of dykes.
These are most numerous near the main mass of igneous rock
whence they become fewer as they recede towards the North Sea.
Usually a dyke cannot be traced far: I am not aware that any
single one can be followed completely across the island, though the
well known Cleaveland dyke in the north of England runs for at
least sixty miles, cutting in its course Carboniferous, Permian,
Triassic, Liassic, and Oolitic rocks till it reaches the sea on the coast
of Yorkshire, at a distance of more than 200 miles from the nearest |
point where the sheets of Miocene trap are now visible. In Ber-
wickshire and the Lothians, these E. and W. or N.W. and S.H.
dykes, often less than half a mile long, are well shown; in Ayrshire
they become still more numerous, traversing the coal-field and
altering the coal seams; in Arran and Cantyre their number still
increases ; until, after a wonderful profusion of them in Islay and
Jura, they reach the great volcanic chain of the Hebrides. From
their manifest intimate connection with that chain, from the fact
that they cut through all the formations they encounter up to and
including the Chalk, and that they cross faults of every size that
may lie in their way, I regard these dykes as of Tertiary age. If
this inference is sustained, as I have little doubt it will be, by a
more detailed investigation of the north-western districts, it presents
us with striking evidence of the powerful activity and wide range of
the volcanic forces in our country during the Miocene period. With
these dykes (to which further allusion will be made in the sequel),
and the Tertiary igneous masses from which they proceed, the record
of volcanic action in Britain appears to close.
This brief reference to the proofs of contemporaneous volcanic
eruptions during the growth of the successive geological formations
in the British Islands may suffice to indicate the wide area of re-
search which here presents itself to geologists. Let me allude to
one or two portions of this broad field, which seem to me worthy of
special notice.
One of the first features to arrest attention is the singular per-
1 See Scenery of Scotland, viewed in connection with its Physical Gainey p- 278
472 Geikie—Volcanic Rocks of Great Britain.
sistence of volcanic phenomena in a limited area. This remark
applies either to our country viewed as a whole, or to many of its
minor districts. These islands are but a small fragment of the
surface of the globe, and yet we see that volcanic action has been
rife here from Lower Silurian up into middle Tertiary times. But
the fact comes before us still more impressively when we discover
it in the geology of a single county, or even of a parish. Take, as
an illustration, the neighbourhood of Edinburgh within a radius of
ten miles from the town. First and oldest comes the long range of
the Pentland and Braid Hills, consisting of a mass of bedded
igneous rocks in a middle series of the Old Red Sandstone. These
old lavas reach a thickness of 4,000 or 5,000 feet. Next in chrono-
logical order are the Calton Hill and lower portion of Arthur’s Seat,
which mark the continuance of volcanic action (though in a lessened
degree) into the Lower Carboniferous period. The Carboniferous
rocks for miles around these hills are full of the traces of contem-
poraneous volcanos, sometimes in the form of sheets of tuff marking
the occurrence of little detached tuff-cones, sometimes in wider areas
of tuff, basalt, and dolerite, where a group of minor volcanic vents
threw out showers of ash and streams of lava. ‘To the east rise the
isolated Garlton Hills, which date from before the Carboniferous Lime-
stone; westwards, scores of little basaltic crags and rounded tuff-
hills mark out the lower Carboniferous volcanos of Linlithgowshire.
To the north the endless crags, hills, and hillocks of the Fife coast
contain the record of many eruptions from the middle of the
Calciferous Sandstones high up into the Carboniferous Limestone
group. Hven the Coal-measures of that county are pierced with
intrusive bosses of trappean agglomerate which indicate the position
of volcanic vents, possibly of Permian age. The same or a more
recent date must be assigned to the later unconformable agglomerate
and basalt of Arthur’s Seat. Nor is this the whole. Latest of all,
come innumerable trap-dykes, running with a prevalent east and
west trend, and cutting through all the other rocks. These, for the
reasons already stated, may, with probability, be assigned to a
Tertiary age. Here, then, in this little tract, about the size of a
small English county, there are the chronicles of a long series of
volcanic eruptions, beginning in the middle of the Old Red Sand-
stone, and coming down to a time relatively so near our own as that
of the Miocene rocks. Nor is this by any means an exceptional
district. Illustrations of a similar persistence of volcanic action
may be gathered in many other tracts of equally limited extent.
Another fact, which a general survey of the character of our
volcanic rocks soon brings before us, is that, as a whole, those of
earlier date differ distinctively in composition from those of more
recent origin. From the first traces of volcanic activity in this
country up to about the close of the Old Red Sandstone or beginning
of the Carboniferous series, the interbedded (that is, contemporane-
ous) igneous rocks consist for the most part of highly feldspathic
masses, to which the name of clinkstone, claystone, compact feld-
spar, porphyry, hornstone, felstone, etc., have been given. In most
Geikie—Voleanic Rocks of Great Britain. 473
of these rocks there is an excess of silica (55 to 80 per cent.), which
is sometimes found separated out into distinct granules. On the
other hand, from the upper part of the Old Red Sandstone, or the
lower members of the Carboniferous series, up to the end of the
long history, the erupted masses are chiefly augitic, as basalts and
dolerites (or greenstones as the latter have been usually termed in
Scotland). In these rocks free silica is not a normal constituent,
while the alkalies, alkaline earths, and metallic oxides form on an
average about half of the whole mass. In the former class the acid
element predominates, in the latter the bases are specially con-
spicuous. According to Durocher the earlier series arose from an
upper acid magma, while those of later age came up from an under-
lying basic magma. Were these rocks subjected to further and
more detailed chemical examination, additional knowledge might
possibly be acquired respecting the history of the changes which
have taken place within the crust of the earth.
As geologists, however, it is important for us to note that, though
two classes of volcanic rocks can thus be determined by analysis
of their composition, no broad essential distinctions appear to be
traceable in their mode of occurrence. The earlier volcanos, which
threw out siliceous lavas and ashes, seem to have acted very much
in the same way as those of later date, which gave out the heavier
pyroxenic lavas. Certain minor differences are indeed readily ob-
servable. Thus the older lavas occur as a rule in much thicker
beds than the later ones, which, indeed, are distinguished by that
markedly bedded character which results from the number and thin-
ness of their successive flows. As a concomitant of this arrange-
ment also, columnar structure is much more frequent among the
pyroxenic than among the silicious rocks. Perhaps, if these and
other distinctions were collected and compared, each class of rocks
might be found to possess certain characteristic peculiarities of its
own, sufficient when taken together to give us a type for general
reference. Nevertheless, in its broader features, there would seem
to have been a striking uniformity in volcanic action from the
earliest times down to our own day.
This leads me to remark that a study of the igneous rocks of
Britain furnishes no proofs that volcanic action has been slowly
diminishing in intensity during past geological time. The amount
of volcanic material preserved in our Old Red Sandstone group
probably exceeds that of our Silurian system, even after all due
allowance for the greater denudation of the older formation. The
number of distinct volcanic centres traceable among the Carbonifer-
ous rocks in like manner surpasses that of the older formations.
But by much the most extensive mass of volcanic material in these
Tslands belongs to the latest epoch of eruption—that of the Miocene
period. In one mountain alone, Ben More in Mull, these youngest
lavas rise over each other, tier above tier, to a height of more than
3,000 feet; yet their base is concealed under the sea, and their top
has been removed by denudation. We have here, therefore, no
proof of a slow diminution of volcanic activity. The period sepa-
474 Geikie— Volcanic Rocks of Great Britain.
rating the Miocene basalts from the New Red Sandstone trap-rocks,
which seem to come next to them in point of recentness, was im-
mensely vaster than that which has elapsed between the Miocene
basalts and the present time. There is thus no improbability in the
eventual outbreak once more of the subterranean forces. Nay, fur-
ther, were a renewed series of volcanic eruptions to take place now,
they might in the far distant future be thrown together with those
of Miocene date, as proofs of one long period of interrupted volcanic
activity, just as we now group the igneous rocks of the lower
Silurian, or of any other geological formation. So near to us, ina
geological sense, are those latest and grandest of our volcanic
phenomena.
Among the different forms assumed by our igneous rocks, one of
the most interesting and, at the same time, most full of difficulty,
is that of the trap-dykes. To my own mind there are few parts of
the geology of the country so hard to understand as the extravasa-
tion of the thousands of dykes by which the north-western portion
of this island is so completely traversed.!. For the reasons already
assigned, I would refer the leading system of these dykes to the
same geological age as the Tertiary volcanic rocks of the north-west.
Yet we find them rising to the surface, and extending for leagues,
to a distance of fully 200 miles from the nearest point of the basaltic
plateaux. Did they reach the surface originally? If so, were they
connected with outflows of dolerite, now wholly removed by denuda-
tion? JI confess that this supposition has often presented itself to
me as carrying with it much probability. It seems to me unlikely
that so many thousands of dykes should have risen so high as the
present surface, retaining there (as shown by deep mines) much the
Same proportions as they show many fathoms down, and yet that
none of them should have reached the surface which existed at the
time of eruption. I regard it as much more probable that some of
them, at least, rose to daylight, and flowed out as coulées, even over
parts of the south of Scotland and north of England, where all trace
of such surface masses has long been removed. Some of the surface-
masses of dolerite in these districts may indeed be of Tertiary age ;
yet the proofs which the great Miocene basaltic plateaux present of
enormous denudation are so striking as to make the total disappear-
ance of even wide and deep lava-currents quite conceivable.
But a much more serious difficulty remains. ‘These dykes, as a
rule, do not come up along lines of fault, yet they preserve wonder-
fully straight courses, even across fractured and irregular strata.
Hach dyke retains, as a rule, a tolerably uniform breadth, and its
sides are sharply defined, as if a clean, straight fissure had been
widened and filled up with solid rock. More than this, they are
1 Boué felt this difficulty, but he conceived that the fissures had been filled from
above by masses of basalt, erupted at different points, and spreading over the country,
though now removed by denudation. He says :—‘‘ Nous croyons infiniment probable
que ces filons ont tous été formés de méme [7.e., remplis par des courans de lave dans
leur marche], malgré les grandes destructions qu’ entraine cette supposition, et que
rarement il y en a eu quelques-uns qui ont été remplis latéralment ou de différentes
maniéres bizarres.’’—G'éol. d’ Ecosse, p. 272.
Geikie— Volcanic Rocks of Great Britain. 475
found cutting across large faults without any deflection or alteration.
In short, no kind of geological structure, no change in the nature of
the rocks traversed, seems to make any difference in the dykes.
These run on in their straight and approximately parallel courses
over hill and valley for miles. The larger faults of this country
tend to take a north-easterly trend, and correspond in a general way
with the strike of the formations. At right angles, or more or less
obliquely to these, are numerous faults of lesser magnitude which
follow roughly the dip of the rocks. But though these different
systems of fissures already existed, and, as we might suppose,
would have served as natural pathways for the escape of the sub-
terranean melted rock towards the surface, the latter rose through a
new series of fractures, often running side by side with those of
older date. How were these new fractures produced, and how is it
that they should run through all formations, up to and including the
older parts of the Miocene basalts, not as faults, with a throw on
one side, but as clean straight fissures, with the strata at the same
level on each side? I do not pretend to answer these questions.
Let me only remark that had the trap-rock been itself the disrupting
agent it would have risen through the older fractures which already
existed as the planes of least resistance. The new fissures must be
assigned to some far more general force, of the action of which the
trap itself furnishes perhaps additional evidence.
Another feature of our igneous rocks, deserving more special
consideration, is the occurrence among them of true vents, or the
sites of volcanic orifices. A very considerable number of these
vents is filled up, not with basalt, dolerite, or other melted rock (in
which cases the character of the mass as occupying an old vent is
apt to be less distinct), but with a coarse agglomerate consisting of
fragments of different trap-rocks, with pieces of the surrounding
sedimentary strata. Such vents are sometimes not larger than a
dining table. In many cases, where the material filling them is fine
in texture, it is well stratified ; but its beds are on end, or thrown
into different inclined positions. The strata around them are much
indurated, and frequently, perhaps usually, are bent sharply down
round the margin of the vent, as if the ash or agglomerate, from
contraction or otherwise, had sunk and pulled the adhering strata
down with it. A careful mineralogical study of these vents, and of
the strata around them, would doubtless reward the observer with
the detection of many points of similarity to the products of modern
volcanos. Instructive sections of these rocks abound along the
coast line of Fife and Hast Lothian, and they occur likewise in
Ayrshire.
It may be possible eventually to arrive at some approximate
realization of the form assumed by the surface of the country during
successive phases of volcanic action. There are, indeed, indications
that the eruptions were apt to occur along lines of broad valley.
The long depression, for instance, between the Highlands and
Southern Uplands of Scotland continued to be the site of active
volcanos during the Old Red Sandstone and Carboniferous periods ;
476 Geikie— Volcanic Rocks of Great Britain.
yet the high grounds on either side seem to have in great measure
escaped, for few of the trap-beds, or of the “necks,” marking the
points of eruption, have as yet been detected there. Again, the
Tertiary basalts of the north-west lie in a long hollow (at least as
old as the Lias) scooped out of the metamorphosed Silurian and
Laurentian rocks. In these instances it is evident that the numerous
volcanic orifices were grouped linear-wise.
One other part of the subject I would allude to as deserving
of inquiry. There seem to me indications that local but well-marked
metamorphism and the extravasation of syenitic and granitic rocks
have taken place in connection with some of our most recent volcanic
phenomena. In Skye, for example, as first pointed out by Maccul-
loch, the Lias limestones are much altered and pierced by masses of
syenite, which is in some places a true granite. This crystalline
rock must have been erupted after the deposition of the middle
Oolitic rocks, for it disrupts and sometimes overlies them. It is
manifestly connected with the trappean plateaux and dykes of that
region. Southwards in Mull, masses of syenite of a like kind
are found in the heart of the great Tertiary basalts, and these basalts
show there a marked change in texture and aspect, as if they had
been more or less metamorphosed. Still further south lies the
granite of Arran, which is, at least in part, of later date than the
lower Carboniferous rocks, for these are pierced by it. In and
around it, as is well known, there is a profusion of trap-dykes
like those of Skye and Mull. This association of syenite or granite
with hundreds of dykes, or with vast piles of basalt, deserves to be
worked out carefully in the field. It will, doubtless be found to
furnish additional data towards elucidating the origin of granite, and
even perhaps some portion of the still obscure subject of metamor-
phism.
In concluding these somewhat desultory remarks, let me add that
I have brought this subject under the notice of the Section with the
view of indicating a field of research in British geology where it
appears to me that much remains to be discovered, and where the
labourers are but few. There was indeed a time, still within the
recollection of some of our older members, when the igneous rocks
of this country received a much larger share of attention than they
do now. After they had ceased to furnish material for the battles of
the Vulcanists and Plutonists, they continued to be studied by able
observers, more especially in Scotland, where they attain their
ereatest prominence. Foremost were the names of Macculloch,
Jameson, and Boué, who, with their associaies and disciples, worked
long and well until they had given to the igneous rocks of this
country an European reputation. Since their days, however, this
branch of the science seems in this country to have gone sadly out
of fashion. De la Beche, Murchison, Sedgwick, Ramsay, and others,
have indeed furnished excellent illustrations of the geology of
different parts of the country where volcanic rocks abound. But,
apart from local or descriptive geology, little has recently been done
in the investigation of our volcanic rocks.
Correspondence. 477
As a result of this neglect, the nomenclature of this portion of
British geology has been virtually at a stand for about half a
century. While so much has been done in this respect by chemists
and geologists abroad, we are but little further forward than when
the great outlines of the subject were sketched long ago by the early
leaders in the science. The same vague names, the same confused
and defective arrangement, the same absence of careful chemical and
mineralogical analysis, so excusable in the infancy of the science,
still disfigure our geological writings and even the best of our
geological collections. YField-geologists must be content to bear
their share of the blame, yet it is not from their hands that the
needed reform is mainly to be looked for. They can do but little
till chemistry comes to their aid with information regarding the com-
position of the rocks which they investigate, and the extent to which
the nomenclature adopted in other countries can be applied in their
own. Surely the time must come ere long when it will be deemed a
task worthy of years of long and patient research to work out the
nature and history of the volcanic rocks of this country. Such a task
will not be the work of merely a single observer. It will require
the labour of the geologist skilled to glean the data that can only be
gathered in the field, and of the chemist, who, aided and guided by
these observations, shall seek to determine the composition of the
different igneous rocks, and the relation which in this respect they
bear to the rocks of other regions, and to the products of modern
volcanos. But, whether distant or near, the day will doubtless
arrive when we shall be able to connect into one story, as far at
least as our fragmentary records will permit, the narrative of the
varied volcanic eruptions which from early geological times have
taken place in the British Islands, and to link that chronicle with
the long history of volcanic action over the globe.
CORRESPONDENCE.
———
THE CHEMISTRY OF THE PRIMEVAL EARTH.
By referring to page 432 of the September Number of the Guo-
LogicaAL Magazine it will be seen that every effort was made on the
part of the Editors to furnish as complete a list of corrections as possible
of Dr. T. Sterry Hunt’s Lecture, which appeared in August last. On
August 27th—the MaGazinr having gone to press—we received the
subjoined letter from Dr. Hunt, which we publish intact, only
omitting those errata which are already noticed in our last Number.
We are glad Dr. Sterry Hunt does the short-hand writer the justice
to state that he is doubtless a competent reporter, and has in most
cases reproduced his language with fidelity,—the errata being for the
most part obvious to the scientific reader, and that they do not in
any way affect his argument, all the points of which may be well
enough understood from the report. We cannot, however, agree
with Dr. Sterry Hunt in considering the abstract, which appeared
in the Chemical News of June 27th, superior to the very full report—
478 Correspondence.
faulty though it be—which appeared in the Grotoctoan Macazine
for August last.—Hoprr. .
To the Editor of the GrotocicaL Macazine.
Srr,—In the number of your Macazrnx for August appears a
report of a lecture delivered by me at the Royal Institution on the
31st of May, on the Chemistry of the Primeval Earth. It is there
described as “a full report taken down verbatim in short-hand, and
now printed for the first time.” For the sake of your numerous
readers I regret that this report, disfigured by many errors, should
have appeared in the pages of the GronogicaL Magazine. When,
moreover, I am aware that those who counselled its publication were
aware that I had preferred to substitute for it a carefully revised
one, prepared from this short-hand report, together with my own
brief notes containing the heads of my extempore lecture, I can
but feel that the proceeding was inconsiderate and unjust alike to
the lecturer and to your readers. ‘This revised report, as many are
aware, has already appeared in the proceedings of the Royal
Institution, and also in the Chemical News of June 27th, where it is
expressly stated that it is the report revised by the author.
The short-hand writer is doubtless a competent reporter, and has
in most cases reproduced my language with fidelity ; but, especially
in the more technical portions, has fallen into numerous errors, for
the most part obvious to the scientific reader. These, with one or
two little omissions, do not in any way in fact affect my argument ;
all the points of which may be well enough understood from the
report when corrected as below, as the reader may assure himself
by comparing it with my revised report in the proceedings of the
Royal Institution, and in the Chemical News.
I subjoin a list of errata, which will show some of the mistakes
into which the reporter has fallen—in the report published in your
Magazine of August :-—
On page 361.—The six lines from line 25, beginning with “Messrs. Hopkins and
Fairbairn,” present an unintelligible confusion, in reproducing my statement, that
these gentlemen had shown pressure to augment the fusing point of such bodies as
contract in solidifying, and that, as we might suppose, the solidification of the earth
to commence at the centre, the temperature there would not be above that of
congelation.
Page 361, line 30, after “increase” read “ of temperature.”
ms », 48, for ‘first few metals” read ‘‘ elements.”
99
» 362, 4, 82, before ‘‘ gases” read ‘‘ acid.” ;
» 363, 4, 2, for ‘‘whole of the affinity of the acid was” read ‘whole of the
acids were.”
» 364, ,, 6, for “whole” read “most.” It is obvious that dolomite and
gypsum, together with numerous silicated rocks, such as
steatite and serpentine, of which I have elsewhere maintained
’ the aqueous and chemical origin, are excluded.
39, for “their hands” read “‘ at hand.”
Trusting that you will do me the justice to insert the above
remarks and corrections, I remain, Sir,
Your obedient servant,
August 2Ath, 1867. T. Srerry Honr.
” ” ”
Correspondence. 479
BOULDER-CLAY AND DRIFT OF NORFOLK AND SUFFOLK, AND
ON THE NORTH SIDE OF THE THAMES VALLEY.
To the Editor of the GrotocicaL MAGazineE.
Sir,—It is a pity that Mr. Maw should mix up doubts as to the
age of the Boulder-clay capping Corton Cliff with those as to the
age of the Cromer beds. If there is one question connected with
the Drift free from doubt, it is the identity of the capping clay of
Corton with the Boulder-clay of High Suffolk ; and no one would, I
feel sure, be more ready to admit this than Mr. Maw himself, if he
examined the country between Corton and High Suffolk. With the
beds of the Cromer coast, however, the case is quite the reverse ;
for the features displayed by the north and north-east of Norfolk
are so excessively perplexing, that I should desire to pay respect to
the views of any one as to the structure of this part, however much
they differed from what I believed to be the truth, and especially to
those of so courteous an opponent as Mr. Maw; but that gentleman
does not seem to be aware that the physical formation of the country,
apart from any geological question, is entirely at variance with the
diagram illustrating his paper,—the whole of the land between the
Boulder-clay country of High Norfolk and Suffolk, and Cromer,
being (except where the valleys of the Yare and Bure cut through
it) one continuous table land: and, although the elevations are not
given in the map, the country behind Cromer and Sherringham
cannot, I imagine, be any lower than the High Suffolk country from
which Mr. Maw starts in his diagram. Another error of fact into
which he has fallen is that of confounding my views with those of
Mr. Gunn. The red loam at the base of Corton Cliff, which Mr.
Gunn calls the “Lower Boulder-clay,” and identifies with the
Cromer Till, I regard as the mud deposit overlying that Till called
by Sir Charles Lyell the ‘contorted drift.” Mr. Gunn finds his
Upper and Lower Boulder-clays in the Cromer and Hasboro’ cliff
sections, whereas I] do not recognize any portion of the Upper
Glacial (and but very little of the base of the Middle) along the
whole twenty miles line of cliff from Hasboro’ to Weybourne. Mr.
Gunn further seems disposed to identify his “laminated beds” with
the Chillesford-clay, whereas I cannot discover their geological
existence, and regard them as only the easterly modification of the
Weybourne sand. Immediately upon the distribution (in July,
1865) of my small map of the Hast of England Drift, and remarks
in explanation, Mr. Harmer, of Norwich, took up the task of map-
ping geologically the beds from the Crag upwards in the Ordnance
sheets of that part of Norfolk which contain the principal drift
deposits. Much time must of course elapse before such a labour can
be completed, or even put in an intelligible shape, although I hope
nothing may prevent his eventually doing so. I mention this
because, having been furnished with all his results as he has pro-
ceeded, and visited with him from time to time all the sections of
importance met with, nothing has yet transpired from them to show
that the views of structure adopted by me are in any material
480 Correspondence.
degree erroneous. Some modifications—not affecting, however, the
main points of structure—I perceive, will have to be made, especially
the absence of the Middle Glacial sands in the north-west part of
central Norfolk, and the presence there of extensive Post-glacial
gravels; and I think it not improbable that the Till of Cromer,
which in the structural section given by me in the 22nd volume of
the Quarterly Journal of the Geological Society, is shown as occupying
the same position of inferiority to the contorted drift as that pos-
sessed by the Chillesford clay, although necessarily for want of
connexion along the line of section distinguished by a separate letter,
may prove to be an expansion of that clay itself. It is a step,
however, gained, that one point, for which I have long contended, is
now admitted to be correct by my principal opponent,! viz. the
superiority of the Chillesford shell-bed to the Fluvio-marine Crag ;
and that the identity which I pointed out between this bed and the
Upper Crag of Mr. Taylor, has now received the assent of Mr.
Taylor, Mr. Gunn, and Mr. Maw.
Perhaps you will permit me to observe, in reference to Mr. Daw-
kins’ letter respecting the Boulder-clay of Havering, that if by the
phrase, ‘‘on the southern side of the range of heights that form
the northern boundary of the Thames Valley,” he means to imply
that the Boulder-clay les in the valley of the Thames, 1 demur
wholly to such an implication. The patch at Havering (as Mr.
Dawkins knows) is shown in my survey map, placed in the library
of the Geological Society, and its position illustrated by section.” It
may be seen from the map and sections that the heights of the
north side of the Thames Valley are formed of Bagshot sand and
Boulder-clay together (the latter having taken the place of the
former, and of the uppermost part of the London clay), and that the
northern valley slope has been cut down from these two formations
indifferently ; so that, imstead of the Boulder-clay at Havering lying
on the southern side of the heights, it is essentially a part of those
heights themselves.—I am, Sir, your obedient servant,
SrearLes V. Woop, Jun.
BRITISH FOSSIL CORALS.
To the Editor of the GroLoGgicaAL MAGAZINE.
Dear S1r,—The generic name of the Carboniferous corals, formerly
confounded with Aulophyllum, should be Oyclophyllum, not Cyclocyathus
(see Gor. Mac., September, 1867, p. 416). There is an error in
my monograph of the Liassic Corals, which makes Trochocyathus
Moorei, Kd. and H., stand in the place of Thecocyathus Moorei,
Ed. and H. As these errors may give rise to much bewilderment
will you kindly insert this note. Yours truly
P. Martin Duncan.
September 18th, 1867.
1 Fisher, Quar. Journ. Geol. Soc., Vol. xxiii. p. 175.
2 See also Section No. 4 of my paper in the forthcoming number of the Quarterly
Journal of the Geological Society, and Vol. ILI. p. 57, of the GzonogicaL Magazine.
soe Z
pie
fees aN
Age a Me
ve ale nS
eal
ee
CLV PLAX.
Vo
507.
ol: Mag: 16
Gt
ir)
ra
a
S
=
Ee
oO
.
6.3.
C
Wy
TS
4
4
at two periods.
OMG NEN |;
Contraction
ay
te
Oo
unde
kin.del*
GEOLOGICAL MAGAZINE.
No. XLI—NOVEMBER, 1867.
Oi GaieN Asin, (pA see @ pes.
I.—On BreccraTED Formations.
By Joun Rusxin. Esq., F.G.S.
(PLATE XX.)
(ConTINUED FROM THE AuGcusT NumBER, P. 339).
i WROTE the first of these papers more with a view of obtaining
some help in my own work than with any purpose of carrying
forward the discussion of the subject myself. But no help having
been given me, I must proceed cautiously alone, and arrange the
order of my questions; since, when I have done my best as care-
fully as I can, the papers will be nothing but a series of suggestions
for others to pursue at their pleasure.
Let me first give the sense in which I use some necessary words :
1. Supposing cavities in rocks are produced by any accident, or
by original structure (as hollows left by gas in lava), and after-
wards filled by the slow introduction of a substance which forms an
element of the rock in which the cavities are formed, and is finally
present, in the cavities, in proportion to its greater or less abundance
in the rock ; I call the process “secretion.”
2. But if the cavities are filled with a substance not present (or
not in sufficient quantity present), in the surrounding rock, and
therefore necessarily brought into them from a distance, I call the
process, if slow, “infiltration” ; if violent, “ injection.”
It is evident that water percolating a rock may carry a substance,
present in the mass of it, by infiltration, into the cavities, and so
imitate the process of secretion. But there are structural differences
in the aspect of the two conditions hereafter to be noticed. The ex-
istence of permanent moisture is however to be admitted among
conditions of secretion; but not of fluent moisture, introducing
foreign elements.
3. If a crystalline or agatescent mass is formed by addition of
successive coats, I call the process ‘“ accretion.”
4. But if the crystalline or agatescent mass separates itself out of
another solid mass, as an imbedded crystal, or nodule, and then,
within its substance, divides itself into coats, I call the process
“concretion.” The orbicular granite of Elba is the simplest instance I
can refer to of such manifest action; but all crystals, scattered
equally through a solid enclosing paste, I shall call “concrete ”
crystals, as opposed to those which are constructed in freedom out of
VOL. IV,—NO. XLI. 31
482 Ruskhin—Brecciated Formations.
a liquid or vapour in cavities of rocks, and which I shall call
“‘ accrete. ”
The fluor nodules of Derbyshire, and amethystine nodules of
some trap rocks, present, in their interiors, the most beautiful
phenomena of concrete crystallization, of which I hope to give
careful drawings.
It is true, as I said in the last paper, that these two processes are
perpetually associated, and also that the difference between them is
sometimes only between coats attracted and coats imposed. A small
portion of organic substance will, perhaps, attract silica to itself, out
of a rock which contained little silica in proportion to its substance ;
and this first knot of silica will attract more, and, at last, a large
mass of flint will be formed, which I should call “concrete ;” but if
a successive overflowing of a silicious spring had deposited succes-
sive layers of silica upon it, I should call it “accrete.” But the
resemblance of the two processes in such instances need not inter-
fere with the clearness of our first conception of them; nor with
our sense of the firm distinction between the separation of a solid
mass, already formed, into crystals or coats in its interior substance,
and the increase of crystalline or coated masses by gradual impo-
sition of new matter.
Now let me re-state the scope of the questions, for the following
out of which I want to collect materials :—
I. I suspect that many so-called ‘‘ conglomerates” are not conglo-
merates at all, but concretionary formations, capable, finally, of
complete mechanical separation of parts; and therefore that even
some states of apparently rolled gravel are only dissolutions of
concretionary rock.
Of course, conglomerates, in which the pebbles are fragments
of recognizable foreign rocks, are beyond all possibility of chal-
lenge; as also those in which the nodules could not, by any chemis-
try, have been secreted from the surrounding mass. But I have in
my hand, as I write, a so-called “conglomerate” of red, rounded, flint
“pebbles,” much divided by interior cracks, enclosed by a finely
erystallized quartz ; and I am under the strongest impression that
the enclosed pieces are not pebbles at all; but secretions — the
spots on a colossal bloodstone. It is with a view to the solution of
this large question, that I am examining the minor structure of
brecciated agates and flints.
II. It seems to me that some of the most singular conditions of
erystalline metamorphic rocks are the result of the reduction of true
conglomerates into a solid mass; and I want therefore to trace the
changes in clearly recognizable conglomerates, where they are affected
by metamorphism ; and arrange them in a consistent series.
III. I cannot, at present, distinguish in rocks the faults, veins, and
brecciations, caused by slow contraction, from those occasioned by
external pressure or violence. It seems to me now that many dis-
tortions and faults, which I have been in the habit of supposing the
result of violence, are only colossal phenomena of retraction or con-
traction ; and even that many apparent strata have been produced by
Whitaker—On Subaérial Denudation. 483
segregation. A paper, on this subject, of Mr. George Maw’s, put into
my hands in May, 1863, gave me the first suggestion of this possi-
bility.
I shall endeavour, as I have leisure, to present such facts to the
readers of this Magazine as may bear on these three enquiries; and
have first engraved the plate given in the present number in order
to put clearly under their consideration the ordinary aspect of the
veins in the first stage of metamorphism in the Alpine cherts and
limestones. The three figures are portions of rolled fragments ;
it is impossible to break good specimens from the rock itself, for it
always breaks through the veins, and it must be gradually ground
down in order to get a good surface.
Fig. 1 is a portion of the surface of a black chertose mass; rent
and filled by a fine quartzose deposit or secretion, softer than the black
portions and yielding to the knife: neither black nor white parts
effervesce with acids : it is as delicate an instance of a vein with rent
fibrous walls as I could find (from the superficial gravel near Geneva).
Fig. 2 is from the bed of the stream descending from the Aiguille
de Varens to St. Martin’s. It represents the usual condition of rend-
ing and warping in the flanks of veins caused by slow contraction,
the separated fraements showing their correspondence with the places
they have seceded from; and it is evident that the secretion or in-
jection of the filling white carbonate of lime must have been con-
current with the slow fracture, or else the pieces, unsupported, would
have fallen asunder.
Fig. 3 is from the bed of the Arve at St. Martin’s, and shows this
condition still more delicately. The narrow black line traversing the
white surface, near the top, is the edge of a film of slate, once attached
to the dark broad vertical belt, and which has been slowly warped from
it as the carbonate of lime was introduced. When the whole was
partly consolidated, a second series of contractions has taken place ;
filled, not now by carbonate of lime, but by compact quartz, traver-
sing in many fine branches the slate and calcite, nearly at right angles
to their course.
I shall have more to say of the examples in this plate in con-
nection with others, of which engravings are in preparation.
IJ.—On Susatrian DENUDATION, AND ON CLIFFS AND HscaRPMENTS
OF THE CHALK AND Lower TrrtiIary Bens.
By Wixtiiam Wuitaker, B.A. (London), F.G.S.,
Of the Geological Survey of England.
[PART II.]
4.—Chalk Escarpments.
HE graceful outlines, smooth curves, and flowing contours of the
Chalk hills are well known to southern geologists; indeed these
hills are the most marked feature of the south-east of England.
Those who hold that their form has been given by the sea, point to
484 Whitaker—On Subaérial Denudation.
the winding ridge, and say how like it is to many a coast with its
succession of capes and coves; even so distinguished a writer as
Sir C. Lyell remarking that “the geologist cannot fail to recognise
in this view (of part of the South Downs) the exact likeness of a
sea-cliff.’* And truly it is so; but let us examine this likeness
more closely, and it will be seen that the argument founded on it,
plausible enough on the surface, is superficial only, and fails utterly
when rigorously tested.
For this purpose let us place ourselves at some spot whence a
large extent of these hills may be seen. None perhaps can be
better than the hill crowned by Totternhoe Camp, in Bedfordshire,
a projecting spur of the lower ridge of the Chalk (for there are two
escarpments in that neighbourhood, one formed by the Chalk Marl
and the bottom part of the flintless Chalk; the other and larger by
the mass of the latter and the bottom part of the Chalk-with-flints).
Thence let us look eastward southward and westward along the
higher range, of which a long expanse unfolds itself to the view,
across the Thames even to the “‘ White Horse Hill” in distant
Berkshire. The screen of even-topped combe-cut hills, shutting off
all view beyond, with its succession of swelling headlands and in-
curved bays, at once impresses the mind with the notion of an old
coast-lme, and but little imagination is needed to picture the sea
beating furiously against the jutting capes, or rippling gently up
the sheltered hollows.
But having indulged in a very pleasant day-dream, and transported
ourselves for the time to Dover cliffs, Beachy Head, or the great
Chalk buttresses of the Isle of Wight, let us descend to sober prose
and our mental photograph will quickly fade, and soon be but “the
baseless fabric of a vision, Jeaving not a wreck behind.” Reason
asks what coast is this ridge like? it is not enough that it should be
like a coast, but it should be like a Chalk-coast: ‘‘it is not a mere
resemblance that should correlate different things; there should
be a specific character in everything that is to be generalised.” ?
The answer comes at once: it is like a coast along rocks of different
hardness (the softer yielding to form bays, the harder resisting to
form headlands), and not like one along a rock of much the jsame
nature throughout—it is not like a Chalk-coast.
Now let us examine the great escarpment more closely. Firstly,
we shall find that at its foot there are powerful ever-flowing springs,
thrown out generally at the out-crop of the Totternhoe stone,?
which of course contain much carbonate of lime, as is shown by
the not uncommon occurrence, further down the streams, of twigs
thickly encrusted. Such constant taking away of matter from the
Chalk must wear away that rock; and, given unlimited time, is enough
to get rid of any quantity of it. This is almost a mere matter of
multiplication; if so many tons are carried away in a year, a
1 Elements of Geology, Ed. 6, p. 359 (1865). Sir Charles now allows, however,
that the likeness is deceptive, see p. 449.
2 Hutton, ‘Theory of the Earth,” vol. i. p. 489.
2 The top bed of the Chalk Marl, see Quart. Journ. Geol. Soc., vol. xxii. p. 398.
Whitaker—On Subaérial Denudation. 485
thousand times as many will be carried away in a thousand years,
other things being equal, and so on.
Secondly, if the escarpment were an old sea-cliff weathered down
into a slope, it ought to show some such section as that in Fig. 1, in
which a talus rests against the weathered face of the cliff, only the
higher part of the hill being of bare Chalk. But this is not the
case; large pits are common along most Chalk escarpments, and
they show a more or less clean face of rock from top to bottom.
The supposition that subaérial denudation may have cut back the
hill, and destroyed the cliff with its talus and beach, has been noticed
before. I question, too, if there is a known case of an old cliff that
has weathered to so long and smooth a slope as that of a Chalk
escarpment.
Next let us turn to the country at the foot of the hills, taken up
by the flintless Chalk and the underlying beds. What sort of
surface-deposit is found there? is it made up of water-worn pebbles
like those on our present shores? No indeed, but we commonly
find, on the contrary, broken and subangular flints, like those of our
old river-gravels, sometimes simply scattered over the surface, at
Fic. 1.—Section of an escarpment on the supposition that it is an old cliff.
a. Talus. 6. Face of old cliff. ec. Bare Chalk.
others abundant enough to form small patches of gravel. In
Buckinghamshire there are thin spots of such far out on the wide
pla of the Gault. What can these flints be but the insoluble
residue of the great mass of Chalk that has been slowly dissolved
away, not pounded and worn by the waves? the remains of which
latter kind of process should be looked for rather in such deposits
as the old Tertiary pebble-beds of Kent, and the shingle-flats of the
south-eastern coast.
It is not at one spot only that these things may be seen, but more
or less along Chalk escarpments generally. In some places too a
small stream runs for miles at or near the foot of the ridge: thus a
branch of the Mole near Dorking, and a branch of the Stour near
Ashford.
[ Whilst the first part of this paper was in the press I was taking
a holiday-ramble in the Isle of Purbeck, and noticed there a good
and marked example of the fact that the bottom of an escarpment
is sometimes at a higher level at one place than the top at another.
The level of the Chalk ridge falls westward from Nine Barrow
Down to Corfe Castle by three sloping steps, giving rise to four
different levels (not counting the still lower conical hill on which
the castle stands), the western of which is lower than the bottom of
the escarpment under the higher parts, as shown in Fig. 2.
486 Whitaker—On Subaérial Denudation.
This is an exceptional case of quick fall in the level of a Chalk
escarpment, and I cannot see how such a ridge can have been formed
as a sea-cliff, which has of course a level base. To explam away
the difficulty of the rise of the base-line by supposing that there
have been local sinkings or upheavals, is a groundless and un-
warrantable assumption until such changes have been proved, not
simply imagined. ]
Fic. 2.—Rough outline of the form of part of the Chalk ridge in the Isle of Purbeck.
Ww. Corfe E.
Castle. Nine Barrow Down.
xx. Sea level. ab. Top ‘of Chalk ridge.
1,2. Foot of the ridge. 3. Level of highest part of the foot of the ridge.
5.—Tertiary Escarpments.
The escarpment of the Lower Tertiary beds is neither so high nor
so steep as that of the Chalk; nevertheless it often forms a well-
marked ridge with a somewhat winding course, as on the north and
north-west of London, from Rickmansworth to beyond Hatfield,
along which line the Colne flows south-westward and the Lea east-
ward at the foot of the hills, receiving on their way streamlets that
run down the slopes and carry off the sand and clay of which those
slopes consist. Some of these streams are simply the result of the
drainage of a clay-country, others start as springs from the Drift
gravel which caps the London Clay on the high grounds, and some
end their course in swallow-holes in the Chalk.
The thickly wooded hills of “the Blean,” between Canterbury
and Faversham, show many examples of swallow-holes, the largest
of which have been described by Mr. Prestwich.t When near the
top one sees springs, thrown out from the gravel by the London
Clay, and down the slopes there are small water-courses; but outside
the close woods, which end mostly at the foot of the hills, the ground
is generally dry, the water having sunk into holes at the junction
of the Tertiary beds and the Chalk, which may commonly be seen
at the re-entering angles of the line of outcrop of the latter forma-
tion. From the southern point of these hills to Grove Ferry and
the Reculvers, the London Clay, which forms by far the greater part
of that district, is wholly cut off by the Stour and the Wantsume
channel, not a particle I believe existing on the right side of the
river, and the Oldhaven and Woolwich Beds occur only as outliers ;
in other words, the left bank of the Stour is an escarpment of
London Clay, ete.
In many places the outcrop of the Chalk, and of the beds between
it and the London Clay is masked by a loam, which is nothing but
1 Quart. Journ. Geol. Soc., vol. x. p. 222 (1854).
Whitaker—On Subaérial Denudation. 487
the “‘rainwash ” of the slopes of clay and sand, and is sometimes
thick enough to be worked for bricks. If so much has been left,
how much more must have been washed away altogether,—all, be it
remembered, being the product of mere surface-denudation.
London Clay hills show many traces of landslips, as may be well
seen on the left side of the Lea, where some of the sharper slopes
are made quite irregular by the many falls.
Whilst, therefore, Chalk is in great part carried away in chemical
solution, the clays and sands of the Tertiary beds are wasted by
mechanical means.
Where the dip is at a high angle the Lower Tertiary formations
have no escarpments, or, at all events, give rise to but a slight
feature, as in the Isle of Purbeck, the Isle of Wight, and Surrey ;
whilst where the beds are flat, or dip at a very small angle, they
have a good escarpment, as in Berkshire, Hertfordshire, and Kent.
The great difference which the amount of dip has had in causing
the denuding powers to form a flat or a slope may be well seen in
the Isle of Wight, where the vertical beds of Alum Bay are in a
valley between the Chalk ridge and the rising ground formed by the
gently inclined higher series of Headon Hill.
West and north-west of London there is a peculiarity im the range
and outcrop of the Lower Tertiary beds worthy of notice here.
The escarpment trends nearly north-east and south-west along a
line through Twyford, Rickmansworth, and Hatfield, roughly parallel
to which, and a few miles from it outward, are a number of outliers
(like skirmishers thrown out from the main body) ranged along a
line from the hills near Wargrave and Beaconsfield, through Chal-
font St. Giles, Sarratt, Abbot’s Langley, St. Alban’s, Digswell,
Datchworth, and Bennington. Again, inwards from the escarpment,
but also parallel to it and a few miles from it, there are a few inliers
along a line through Windsor, Pinner, and Northaw. The outliers
I look on as the relics of a former escarpment, and the inliers as the
signs of a future one. The outliers mark a line where denudation
has been delayed (I do not say stopped); the escarpment perhaps
one where it is now delayed; and the inliers one where it will be
delayed (of course on the supposition that no great physical change
takes place), when the part between them and the present escarp-
ment will be cut off as outliers. Hach of these lines is in great
part, I believe, through points where a slight change of dip takes
place, which may have in some measure enabled the beds better to
withstand denudation in the case of the outliers, or may have made
them fall an easier prey to it in the case of the inliers, there being
an inward dip in the former and an outward dip in the latter.
Further out in the Chalk district there are traces of another line of
outliers, better marked westward, along a line through Lane End
(near Wycombe), Turville Common, Nettlebed, and Woodeot Com-
mon (east of Goring). The inner line merges into that of the
escarpment near Reading, and further westward the outer line does
so too. I have noticed like arrangements in line in Kent, but none
so marked as the above, perhaps because the dip is generally less on
488 Whitaker—On Subaérial Denudation.
the northern side of the London basin than on the southern, so that
the beds have a greater chance of spreading over a wider tract.
Of course delays in denudation may be owing also to change of
condition, climatal or otherwise.
: 6.—Chalk and Tertiary Cliffs.
It is usual to talk of cliffs as the work of the sea alone; and
those who say that subaérial actions are too weak to do the work of
denudation in forming hills and valleys are wont to point to what is
now going on along our shores as evidence that the sea and the sea
only is nature’s great tool for making ridges. I am willing how-
ever to meet them on their own ground, thinking that if it can be
shown that the sea alone does not make the cliffs, but is very largely
helped by those atmospheric actions which they despise, their state-
ments as to the powerlessness of those actions will have all foundation
destroyed, and will therefore fall to the ground, carrying with them
the theories which they support.
Let us examine the Chalk-coast of Kent. The cliffs are for the
most part nearly vertical ; indeed I can call to mind but one place
where this is not the case, the well-known Shakspeare’s Cliff, the
higher part of which is a sharp slope, whilst near the bottom it is
slightly overhanging (on account of a hard bed which stands out).
Sometimes they are quite vertical; hardly ever are they undermined.
Now if made by the sea alone, which can act only at their base,
surely they should mostly overhang ; but, in fact, they often project
slightly at the bottom by a series of small steps. It is clear there-
fore that the upper part wears away as quickly as the lower, and as
the sea can hardly attack the top of the cliff, one hundred feet or
more high, one must look about for some other wearing power that
can.
For that purpose let us go to the cliff-top and see what is going
on there. We shall find that the action of the weather is nearly
everywhere separating masses of Chalk, some of which, from the
slow dissolving away of the surrounding rock, stand out for many
years as pinnacles or needles, whilst others are soon hurled to the
bottom. Where the Chalk is most jointed there of course the power
of frost has most chance of showing itself: where too there are
large pipes of sand and clay in the Chalk small needles are common
along the top of the cliff, as in parts of the coast of Normandy.
When the softer and more yielding beds below the Chalk crop out
near the base for some distance, the fall of the cliff sometimes takes
place on a very large scale, and “undercliffs” are formed. Thus at
Folkestone the porous yielding Upper Greensand has given way to
the influence of springs and to the pressure of the great overlying
mass of rock, which has in consequence slid down over the moist
slippery surface of the Gault. The undercliff of the Isle of Wight
is far longer and broader, and the nearly vertical cliff of hard Upper
Greensand, which has resulted from its formation, is at a great
height above the sea and often a third of a mile distant therefrom,
so that no one can well call it a sea-cliff.
Whitaker—On Subaérial Denudation. 489
In Kent the Chalk escarpment and the Chalk cliff cut one another
obliquely, whilst at the western end of the Isle of Wight the two
are for a wonder parallel; but alas for the advocates of the marine
formation of escarpments! this latter case in no way helps their
theory, for putting aside the consideration of the fact that the
cliff leaves the Chalk and turns southwards to cut through lower
beds, one can see at a glance that the formation of the cliff has in
great part destroyed the feature of the escarpment, of which only
the curved top remains, as shown in the section below. Moreover
Fic. 3.—Section showing the relation of the Chalk cliff and the Chalk escarpment
S. in the Isle of Wight. N.
A ne
a eT < - -
we SS ~
x
ee
Scale about six inches to a mile.
1. Lower Tertiary beds. 2. Chalk with many layers of flints. 3. Chalk with few flints.
4. Chalk without flints. 5. Chalk Marl.
6. Upper Greensand. 7. Gault. x x. Sea-level.
The broken lines show the form of the ground and the continuation of the beds, which must
have existed before the sea-cliff was worn back into the escarpment, and which correspond to
the same as they now exist in those parts away from the sea.
The dotted lines show the further extension of the beds until cut off by the “‘ plain of marine
denudation”? made before the exposure of the land to subaérial actions.
the sea has utterly destroyed the Chalk ridge between the Needles
and Handfast Point in Dorsetshire. Along all Chalk-coasts, indeed,
the antagonism of the two denuding powers is well shown, the
sharp cliffs cutting across the gently curved outlines of hill and
valley that have been caused by long continued subaérial actions,
the sea levelling what these have furrowed.
Let us now turn to the Tertiary coast of Kent. The foreshore of
the Isle of Sheppey (and also of the greater part of the mainland
from Whitstable to beyond Herne Bay) consists of a plain of London
Clay sloping gently seawards. The cliffs are mostly sharp irregular
broken slopes, not altogether cut out by the sea, but formed by the
slipping downwards of masses of London Clay and of the overlying
Bagshot Sand and Drift gravel, which last two form a more vertical
ridge at the top of the slope.
Now it is clear that the waves do not rush up to the top of the
cliff and bring down the clay sand etc., but that the fallen masses
owe their fall to frost, rain, and heat :, the heat of summer to dry up
the beds, and by shrinkage to form fissures down which the rain
may soak; rain to soften and make slippery; frost to divide mass
490 Whitaker—On Subaérial Denudation.
from mass by its irresistible expansive power. That the slips take
place from the top is indeed well known, and good figures of one of ©
them have been given by Mr. Redman.’ I have myself seen a large
and fresh one, and noted the occurrence of a crop of wheat some way
down the slope.
The coast from the Reculvers westward for about two miles is of
a somewhat different character, by reason of the rise of the sandy
beds below the London Clay ; but still the waste of the cliff is from
the top, masses of the clay being constantly thrown down to the foot.
The shape of the cliff is often different, the clay forming a slope at
the top and the sands a more or less vertical wall below. Another
agent too comes into play here—the wind, which when strong
blows away much of the fine loose sand (Oldhaven Beds?) next below
the London Clay. At Oldhaven Gap there is a well-marked cliff run-
ning inward from the shore at right angles, and with a broken slope
on the other (eastern) side. This “chine,” which is about 300 yards
long, and the bottom of which is but little above high-water-mark,
has clearly been formed by land-water, although for the greater part
of the year the insignificant watercourse along it is quite dry, for the
sea has never touched its base, and I believe that it has been cut
farther inland within the memory of man.
The sea, therefore, does not by itself destroy the land, but is largely
helped by atmospheric actions. The former carries away what the
latter bring within its reach. Without the help of rain, frost, ete.,
the sea would spend its force on compact and therefore on compara-
tively unyielding rocks: without the help of the sea these subaérial
forces would soon mask solid cliffs with slopes of débris, and thus
vastly decrease their own destructive power. The two destroying
powers working together in different ways, the sea horizontally
from below, the other set of agents vertically from above,’ cause ten-
fold the destruction of coast that either could do alone.
Most observers indeed are more or less agreed as to the waste
of some cliffs from above, though so far as I know, this knowledge
of the power of surface-actions on the coast has not been applied to
the question of denudation. Sir C. Lyell indeed has said in his last
work, that “the waste of the cliffs by marine currents constitutes
on the whole a very insignificant portion of the denudation annually
effected by aqueous causes ..... the action of the waves and cur-
rents on sea-cliffs, or their power to remove matter from above to
below the sea-level, is insignificant in comparison with the power of
rivers to perform the same task.”
7.— Comparison between Cliffs and Escarpments.
From what has been remarked above therefore it is clear that
1 Proc. Inst. Ciy. Eng. vol. xxiii. p. 186, 1865, where, and in an earlier paper by
the same author (ibid. vol. xi. p. 162, 1854), the destruction of the South-east coast
of England is well treated of.
2 Quart. Journ. Geol. Soc. vol. xxii. p. 412.
3 See Jukes, Brit. Assoc. Rep. for 1862, Trans. of Sections, p. 61.
4 Principles of Geology, Ed. 10, vol. i. pp. 565, 570 (1867).
Whitaker—On Subaérial Denudation. 491
rivers often run along the foot of Chalk and Tertiary escarpments,
whilst, on the other hand, it is very rare for the sea to do so.
Again, an escarpment is remarkable for the comparatively uniform
level of its top for long distances, any change therein being by a
gentle slope; whilst the height of a range of cliffs is ever varying,
and that suddenly and with sharp slopes. Hscarpments, too, are
nearly always the highest part of a district, the ground falling from
them on both sides; cliffs, however, are very rarely so, but are often
backed by higher ground; indeed those cases that I know of Chalk
cliffs being through the highest ground are just where they cut
through the escarpment, as on the north of Folkestone and at Beachy
Head. The same kind of reasoning that has been used with refer-
ence to the features of the Chalk and the Tertiary beds may be
applied to other formations; and how, therefore, an escarpment can
be an old sea-cliff passes my understanding, for the two have nothing
in common and much in opposition, as may be clearly seen from the
following table :—
Comparative TABLE OF THE DISTINCTIVE FEATURES OF ESCARPMENTS AND CLIFFS.
EscaARPMENTS.
(z) Run along the strike, or in other
words, keep to one formation throughout.
H (6) Tops more or less even and nearly
at.
(c) Form the highest ground of a
country, overlooking other parts.
(d) Very rarely have the sea at their
foot, but often springs and watercourses.
_ (e) Often run in more or less winding
eS.
(f) No beach at their foot.
(7) Are now being destroyed by the sea
in places where the sea touches them.
(4) Bases rise towards the watershed
and have nothing to do with the sea-level.
(¢) Those of successive formations run
in more or less parallel lines for long dis-
tances, with plains, vales, or valleys be-
tween.
CLIFFS.
(a) Rarely run along the strike, but at
all angles to it, and cut through many
formations in succession.
(6) Tops mostly very uneven.
(c) Rarely through the highest ground
of a country, but mostly backed by higher
ground.
(d) Sea at their foot.
(e) Run nearly straight, or in curves of
very large radius, when through homo-
geneous rock, and when not broken
through by valleys.
(f) Mostly a beach at their foot.
(g) Are now being made by the sea
(aided by atmospheric actions).
(Z) Bases at the sea-level.
(‘) No such parallel arrangement
known, long fringes of land divided by
belts of sea not being common, except in
such cases as Coral Islands, where the
features have been caused by growth, not
by decay.
What can be more different than these two? It is for those who
say that escarpments are old sea-cliffs to answer the question, and
until that has been done they have little reason on their side.
8.—Concelusion.
All geologists know that rivers have made great. deposits, as for
instance the Wealden Beds, and therefore I do not see how they can
avoid allowing that rivers, etc., have been the agents in effecting a
great amount of denudation, The solid matter of the Wealden Beds
must have existed somewhere before, and must have been worn away
by subaérial actions and carried off by streams (the sea being quite
492 Whitaker—On Subaérial Denudation.
out of the question): more too must have been worn away than
was deposited afterwards by the rivers, for much would be carried
out to sea to form a marine deposit. Of course freshwater beds are
both less common and thinner than marine beds, but so also, as
aforesaid, the comparatively trifling denudation that has formed our
hills and valleys is of far less amount than that which has planed
down vast tracts of country and carried off therefrom a great thick-
ness of rock. Perhaps, indeed, the proportion that the effects of
marine denudation bear to those of subaérial denudation is not far
from the same as that which marine deposits bear to freshwater
deposits.
To those who say that subaérial agents are too small and too weak
for the work which has been put to their credit, it may be answered
that unlimited time would get over that difficulty ; and it should be
borne in mind that good evidence has been brought forward that in
late geological times our climate was far more severe than now, and
that there may have been a far more rainy period before the present
order of things was established; or in other words, that the agents
in question were far more powerful than they now are in these
islands. Great change indeed has taken place in historic times; the
felling of forests, the draining of land, the embanking and canaliza-
tion of rivers, the reclaiming of marshes, and the like human handi-
works having had their effect in lessening rainfall and floods, and
therefore also the wearing action of surface water.
As astronomy has proved the existence of almost boundless space,
so geology needs almost boundless time. The former science gives
us our liveliest picture of infinity, and the latter our best idea of
eternity. When astronomers talk without any opposition of im-
measurable space, surely geologists should be allowed immeasurable
time. The last Wollaston Medallist has eloquently said, ‘“'The lead-
ing idea which is present in all our researches, and which accom-
panies every fresh observation, the sound which to the ear of the
student of nature seems continually echoed from every part of her
works is Time! Time! Time!’’?
Lastly, it seems to me that the discussion on the question of
denudation has been argued on a wrong foundation. Surely, if we
can explain the facts and appearances we see by actions and oper-
ations that can be seen going on at the spot now, we are bound to
take such explanation until it can be disproved, or until a better one
can be given, and we have no right to call in the aid of other and
distant operations, without there is some good sign of their having
been once present (thus for instance with regard to many rock-
basins now far from glaciers, there are unmistakeable signs of their
once having contained ice). As a simple matter of reasoning there-
fore, apart from all scientific truth, we are bound to accept the
theory of subaérial denudation until it can be put aside. Geologists
should not call on those who hold it, and who show its agreement
with things seen, to disprove other theories; but rather should
expect its adversaries to disprove it, and to show firstly, that rain,
1 Scrope, “* The Geology, etc., of Central France,” Ed. 2 (1858), p. 208.
Belt—On the “ Lingula Flags.” 493
rivers, ice, springs, damp, and frost are powerless to wear away
rocks and to cut out escarpments valleys and rock-basins ; and
secondly, that the sea can do and does such work. This, no light
task truly, must be done, if it can be done, not by mere assertions
of individual opinion, or mere statements based on hasty and pre-
judiced observations, but by hard work and sound reasoning. Not
with us, but with our opponents, lies the onus probandi.
Errors IN THE First Part oF THIS PAPER.
Page 451, line 16 from bottom, for “‘action’’ read “ actions.”
Page 451, line 11 from bottom, for “ Portland Stone in part of the Isle of Purbeck ”’
read ** Purbeck and Portland Beds in Dorsetshire.”
Page 453, line 15 from bottom, after ‘‘follow”’ insert “us.”
TiJ.—On tue “ Lincuta Frags,” or ‘“ Festrniog Group”
oF THE DotGeEeLLy District.
By Tuomas Bett, F.G.S.
[PART I.]
HE strata lying above and below the Lingula Flags have already
been well described and illustrated : the Menevian Gronp below,
by Messrs. Salter and Hicks, and the Tremadoc Group above, by
Messrs. Homfray, Ash, and Salter. The great mass of strata lying
between has not fared so well, though several notices of it, to which
I shall refer, have appeared. In the present paper I propose to
describe these strata in detail; and the remarks I have to offer
embody the results of three years’ researches, during part of which
I have had the advantage of the company and able co-operation of
Messrs. Ezekiel Williamson and J. C. Barlow, whose discoveries
I shall have to mention in my description of the rocks and their fossil
contents. To facilitate the study of the district around Dolgelly,
which is exceedingly faulted and complicated, I have carefully
mapped out nearly the whole of the rock exposures. This may
seem to have been unnecessary, seeing that we have already the
Geological Survey maps of the district. But since the officers of
the Survey examined and mapped out the rocks of Merionethshire,
from fifteen to eighteen years have elapsed, and the maps which
then added so much to our knowledge are now far behind our
requirements. The whole of the strata lying between the Tarannon
shale and the Cambrian grits are there coloured alike. Neither the
Arenig nor the Tremadoc rocks are recognised ; and we now know
that the strata there named “ Lingula Flags” include at least three
distinct and diverse groups.
In 1847 Professor Sedgwick separated the Tremadoc rocks from
the “ Lingula Flags,” calling the latter the Festiniog Group. Since
then Mr. Salter has been the pioneer in their investigation. His
discovery in 1863 of Paradoxides Davidis in the slates of St. David’s
gave an impulse to the study of these old rocks, that has resulted in a
rich harvest of Primordial trilobites, chiefly through the indefatigable
494 Belt— On the “ Lingula Flags.”
labours of Mr. Hicks. The strata containing these trilobites have
been separated from the Lingula Flags by Mr. Salter, under the
name of the Menevian Group. The recent discovery by Mr. Hicks
of new forms of Paradowxides in the purple slates, inter-stratified
with the Harlech grits, will probably lead to the classification of
the Paradowides beds as Lower Cambrian. The Menevian Group
will then form the top beds of the lower instead of the bottom beds
of the upper formation and the Lower Cambrian will have a
well-defined paleontological limit upwards. Whilst linked to the
upper series by such general and far ranging forms as Conocoryphe
and Agnostus, it will be distinctly marked off by Paradoxides and
other genera that do not transgress the upper boundary of the
Menevian beds.
The Lingula Flags above the Menevian Group have been divided
by Mr. Salter into the Lower, Middle, and Upper Lingula. In a
paper by Mr. Plant, an abstract of which appears in the Quarterly
Journal of the Geological Society for November, 1866, the same
classification is adopted. Messrs. Salter and Hicks, in the Report of
the British Association for 1866, include the Lingula Flags in the
Festiniog Group, and characterises them as ‘hard siliceous sand-
stone with grey flaky slate, containing Lingulella Davisii.” ‘This
description only applies to the Lingula Flags of South Wales. In
North Wales the arenaceous flags and shales containing Lingulella
Dawvisii only form a subordinate part of a series of dark-blue and
black, fine grained slates, containing trilobites of several genera.
Even when we have divided the group into Upper, Middle, and
Lower, we have still to speak of the Upper division of the
Upper, and the Lower division of the Lower Festiniog, as each
sub-division contains two distinct sets of strata. Recent dis-
coveries have shown that the group includes at least six zones
of animal life, each distinct and separate. I believe that I only
meet the strict requirements of the case when I propose to form
three groups of the strata now included in one. My proposal is, to
restrict the name of the Festiniog Group to the flags containing
TInngulella Davisii and Hymenocaris vermicauda, to which it was
originally applied by Sedgwick, and to form the slates and flags
lying below them, characterised by typical forms of Olenus, into a
new group, which might well be called the Maentwrog Group, as
the strata included in it are exhibited in great perfection at and
around the village of Maentwrog, two and a half miles west-south-
west from Festiniog, For the blue and black slates lying above the
Festiniog Group, as above limited, I propose the name of the Dolgelly
Group, as it is only in the neighbourhood of Dolgelly that both
the members of which it is composed have as yet been found. It
is well characterised by several aberrant forms of Olenus, constituting
the genera, or sub-genera Parabolina, Peltura, Spheropthalmus, and
Dikelocephalus of various authors.
The Maentwrog, Festiniog, and Dolgelly Groups are both litho-
logically and paleontologically distinct. None of the Crustaceans
pass from one group to another, and peculiar genera are found in
Belt— On the “ Lingula Flags.”
495
each. Lithologically, the Dolgelly Group is characterised by soft
black slates, with a black streak; the Festiniog Group by hard
micaceous flags, and the Maentwrog Group by dark-blue, jointed,
ferruginous slates.
Before passing on to a detailed account of these rocks and their
fossil contents, and in order to exhibit clearly their position in the
Cambrian system, I give below a table of the whole of the Cambrian
rocks, showing the proposed classification. and the range of the
genera.
I have not included Calymene, Homalonotus, and Nucula,
recorded by Messrs. Salter and Hicks from rocks at St. David’s—
believed by them to be of Tremadoc age'—as no Tremadoc species
have been found, and all the trilobites belong to Silurian genera.
They will probably form a Lower Arenig Group.
TABLE OF THE CAMBRIAN ROCKS SHOWING THE RANGE OF THE GENERA.
GENERA,
Paradoxides
Anopolenus
Microdiscus ......
IR EIN THY 5 55 «0-0-4 dean
Holocephalina ...
Conocoryphe ... ..
Agnostus
Olenus
erecce
Beeeecacsces
IReliturayieresse sss
Spheropthalmus...
Dikelocephalus ..,
INDODE: 2205200623»:
Angelina
Cheirurus
WAST PK Ee sasadcuce ces
Asaphtus :22000..2).
Ogygia
Hymenocaris ......
Lingulocaris ......
Leperditia .........
Protocystites ......
Bellerophon ......
Lingulella .........
eeeeetcee
eee reessenae
eee eee eceses
Cyrtotheca .........
Conularia .........
Orthoceras .........
Dictyonema ......
Protospongia ......
Buthotrephis ......
Lower CAMBRIAN.
Upper CAMBRIAN.
Bangor |Harlech} Menevian
Slates.
Grits. | Group.
all
Maentwrog | Festiniog |} Dolgelly | Tremadoc
Group.
Group.
Group.
Group.
The Genera marked thus * pass upwards.
1 Report Brit. Assoc., 1866, p. 184.
(To be continued.)
496 Guppy— West Indian Geology.
TV.—Notrs on West Inpran GEoLoGY, with REMARKS ON THE
EXISTENCE OF AN ATLANTIS IN THE Haruty Tertiary PrErzop ;
AND DESCRIPTIONS OF sOME NEw FossILs, FROM THE CARIBEAN
MiocEneE.
By R. J. Lecumere Gupry, F.L.S., F.G.S.
1 INCE the researches of Heer into the Miocene Flora of Swit-
; zerland have invested the theory of a Tertiary Atlantis with
some degree of probability, other observers have come forward with
arguments on the one hand which lend support to that hypothesis ;
whilst on the other hand it has been attempted to prove that the
facts (as to the presumed migrations of plants and animals) are to be
accounted for rather by a connection between Hurope and America
through the Asiatic region. My examination of the Jamaican fossils?
first led me to support a modification of the original view taken by
Heer, and in April, 1866, I communicated to the Geological Society a
paper bearing on the subject. That paper was read on the 20th of
June, 1866, and an abstract of it appeared in the August number of
this Magazine. I propose, on the present occasion, to make a few
remarks on the probability of the former connection between the
eastern and western shores of the Atlantic.
It does not seem to me improbable that we shall ultimately have
to admit that the Tertiary Atlantis was, in all probability, only the
termination of a pre-Tertiary Atlantis, and that the physical changes
produced by the gradual disappearance of the Atlantic land,
and the emergence of land in other regions, gave rise to that
migration of species, the causes of which we now seek to explain.
According to Dana, the North-American continent has been
receiving constant additions during the Paleozoic and Mesozoic
periods; but he has not satisfied us as to the origin of the immense
amount of material necessary for the formation of so much land; and
I would suggest the possibility of that material having been derived,
in part, from land which occupied some portion of the present
Atlantic area. Such land would have permitted the diffusion of
plants, while its shores afforded the means for the migration of
marine animals between America and Europe. Then, if the Atlantic
continent were of pre-Miocene date, and if its destruction and sub-
mergence began in Eocene times, we might be able to account
for the facts observed as to the distribution both of Hocene and Mio-
cene Invertebrata and Plants. Since the Eocene period the Alps, in
part formed of Nummulitic Limestone, have been upheaved, and it
may be assumed that an equivalent amount of depression took place
on some not very remote part of the earth’s surface. The submer-
ence of the Atlantis continued throughout the earlier Tertiaries, may
have left but its higher points, as detached groups of coral islands,
in the later Miocene sea. Dana is of opinion that the Pacific land
has been depressed 6,000 feet in post-Tertiary times.° It is, there-
1 Quart. Journ. Geol. Soc. vol. xxii, p. 281. .
2 Vol. III. p. 373. Quart. Journ, Geol. Soc. Vol. xxii., p. 570.
3 Manual of Geology, p. 587.
Guppy— West Indian Geology. 497
fore, not so improbable that the submergence of the Atlantic and
Pacific continents was, in part, contemporaneous with the upheaval
of large areas in Hurope and America.’
It is possible that we have here an explanation of the com-
paratively limited development of Tertiary formations in North-
America. They are, as we know, chiefly confined to the region about
the Mississippi, and to a narrow belt which extends along the Atlantic
coast. This small development of Tertiary rocks may be due to
the submergence of the area whence the material for the formation
of the American continent was formerly derived. A careful study
of the physical geology of the whole region under consideration
would alone enable us to generalize with safety on this point.
2. A further search in the Lower Miocene beds of San Fernando,
in Trinidad, has been rewarded by the discovery of a shell hitherto
only known by a few examples, obtained by Sir Robert Schomburgk
from a rock in Barbados, and which was described by Professor
Forbes. It is possible that we may hence derive some clue to the
age of the Barbados older Tertiary, which is as yet undetermined.
In order to be clearly understood I shall give a very brief outline of
the geology of Barbados.
Two formations are exposed in Barbados. They have been named
respectively the Coral formation and the Scotland formation. Of
these the former appears by its included organic remains to be of
the same age as the Newer Pliocene deposits of the West Indies.
All the species are still existing. The Scotland formation contains
the well-known microscopic organisms described by Ehrenberg, and
called by him Polycystina. In an “isolated rock” in this formation
Sir Robert Schomburgk found some fossil mollusca. Of these,
three species alone were in a state to admit of description, and they
were named by Professor Forbes, who was inclined to regard them
as Miocene. From that time (1846) to the present no further
examples of these fossils have been discovered. I had the good
fortune to find one of them (the Nucula Schomburgki of Forbes)
in a greenish-gray shale among the middle beds of the Lower
Miocene series of San Fernando. The Nucula in question is a re-
markable species, resembling, especially in the character of its
ornamentation, the N. divaricata of the Pacific, and the N. Cobboldie
of the English crag. In the San Fernando beds fossils are rare, and
difficult of extraction. Several other species accompany the Nucula
in the bed of shale ; but, although enough is seen of them to indicate
that they probably belong, in most cases, to undescribed and extinct
species, they are rarely in a condition for description.
Our information as to the relation of the “isolated rock” con-
taining Nucula Schomburgki to the Scotland formation is not so
precise as might be wished; but, assuming it to be a detached pin-
nacle or boulder belonging to the Lower Miocene it would thus
appear that the Scotland formation is newer than the Lower Miocene,
and may possibly, considering that it is inferior to the Pliocene, be
1 Dana, op. cit., pp. 531, 532; and Lyell, Principles, 8th ed., p. 121.
9
VOL. 1V.— NO. XLI. 32
498 Guppy— West Indian Geology.
of Upper Miocene date. For although the Scotland formation is
different in its general appearance and composition from the Upper
Miocene of San Domingo, Jamaica, Trinidad, and Cumana, yet it
bears in part a similarity to that of Trinidad, in its included and
characteristically abundant minerals ; namely, petroleum, coal, and
selenite.
It may perhaps be inferred from the discovery of Nucula Schom-
burgki in the Lower Miocene of Trinidad that after the deposition
of that formation a depression took place, which led to the existence
of a deep ocean over part of the West-Indian area. This is in-
dicated by the Polycystina beds of Barbados, whose fossils resemble
those dredged from great depths in the sea.!
As the Nucula Schomburgki is an interesting form, I have made a
drawing of the best-preserved example, and three other fossils from
the same bed are also figured herewith, together with some other
species of mollusca from Miocene deposits in the West-Indies ; and
which are not only interesting from their zoological affinities, but
may aid in the identification of rocks of the Tertiary period in the
Caribean area.
3. In the lists of fossils I gave in my paper on the Relations of
the West-Indian Tertiaries, the name Ancillaria glandiformis should
have been included in the San Domingan and Jamaican lists. I am
satisfied from the figures of this variable shell, given by Hérnes, in
his Fossil Mollusca of the Vienna Basin, that the Ancillarie in the
collection of the Geological Society belong to this species, and also
the small and young examples from Jamaica, in the British Museum.
Another link is thus added to those which already connect the
European and Caribean Miocene. The shell I described in the
same paper as Melanopsis cepula (not capula, which is a misprint),
seems to be deserving of generic rank, and I propose to distinguish
it by the name Crepitacella. 'The characters are appended hereto.
The shell described by me under the name of Malea camura occurs
in San Domingo as well as in Jamaica.?
4. As a further result of my researches, I may here state that
I find myself gradually tending towards the belief that the Tamana
series and the San Fernando beds in Trinidad must be separated
from the other deposits in the West-Indies termed Miocene; and
that it would be more correct for the present to limit the term Lower
Miocene to the former, and to class the Anguilla and Antigua Beds
as the lower members of the Upper Miocene. I propose, therefore,
the following classification of the Caribean Upper and Middle
Tertiaries :—
1. Pliocene.
a. Barbados, Guadeloupe, etc.
b, Trinidad (Matura Beds).
1 See Maury, Phys. Geogr. of the Sea (1858), pp. 254, 263.
2 The shell from San Domingo, in the British Museum, labelled Venus circinaria,
is not that species, but more probably Venus rigida_(V. rugosa).
Guppy— West Indian Geology. 499
2. Upper Miocene.
. Cumana.
. Barbuda.
. Trinidad (1. Mornga Series: 2. Caroni Series).
. Jamaica (Vere, Bowden and Upper Clarendon Beds).
San Domingo (Nivajé shale, etc).
. Anguilla.
. Antigua (Chert formation: Conglomerate beds).
. Barbados (Scotland formation).
SRP Asses
3. Lower Miocene.
a. Trinidad (Manzanilla Beds).
6. Trinidad (San Fernando Beds).
c. (?) Barbados (Nucula-rock.)
It will be noticed that I have inserted the name of Barbuda in the
list of Upper Miocene localities given above. Having recently
examined a small collection of fossils from that island, I have deter-
mined the following species from it :—
Oliva cylindrica, Sow. Bulla striata, Brug.
Nassa solidula, Guppy. Tellina biplicata, Conrad.
All these species occur in the Miocene ; and thus Dr. Duncan’s
conclusion, as to the existence of the Middle Tertiary in that island,
is now confirmed by the discovery of these mollusca.
5. Mr. Jeffreys, in his paper on “ Dredging among the Hebrides *
notices that the diffusion of univalves is slower than that of bivalves.
This fact may help us to explain why there should be comparatively
so large a proportion of bivalves common to the Middle Tertiaries of
the United States, and the West-Indies. The species. of mollusca I
have ascertained to occur in both these areas are as follow :—
Univalves.—FPetaloconchus sculpturatus, Lea.
Dentalium mississipense, Conrad.
Latirus infundibulum, Lam.
Bivalves.— Artemis acetabulum, Conrad.
Tellina biplicata, Conrad.
Pecten Mortoni, Conrad.
» comparilis, Tuomey and Holmes.
Lucina pennsylvanica, Linn.
Ostrea virginica, Gruel.
Teredo fistula, Lea.
Chama arcinella, Lam.
Thus we have another fact pointing to the greater facilities which
must have existed for migration between the Huropean and Caribean
Middle Tertiary seas than between the latter and North America.
For, although but few Gasteropoda are common to the European and
the Caribean Miocene, yet very many-.are closely allied, which is not
the case with those of America. Further, all those species of
mollusca, which Conrad and other authors find to be common to
both continents, are bivalves. And there are as many bivalves
common to the Huropean and West-Indian Miocene as there are to
the latter, and that of the United States.
1 Ann, and Mag. N.H., 3 ser., vol, 18, p. 387, (Nov. 1866).
500 Guppy— West Indian Geology.
Descriptions of a New Genus and Six New Species of Mollusca, from
the Caribean Miocene.
I.—Crepitacella.— gen. nov.
Shell turreted, cono-cylindric, last whorl large, rounded; aperture large, with a
broad and short anterior canal. Columella twisted; peristome simple, prominent.
C. cepula, Guppy, Quart. Journ. Geol. Soc., Vol. xxii. p. 580, pl. xxvi. fig. 14.
Upper Miocene, Cumana.
The true position of this shell is probably in the neighbourhood of the family
Buccinide, in which I have provisionally placed it. Its nearest relation known to me
is Cyllene pulchella, Adams.
Names or New Srecies Figurep anp DerscriBeD.
Fig. 1. Leda incognita. Fig. 4. Stomatia eidolon.
' 5, 2. Leda bisuleata. 5, 5. Nucula Schomburgkt.
», 98 Lornatina coix-lacryma. » 6. Mactra subovalina.
I.—Stomatia eidolon. (Fig. 4.)
Shell depressed, ear-shaped, few-whorled, radiately striate, with a furrow near the
outer angle of the whorls; spire small, depressed.
This little shell resembles a Haléotis without holes, and for this reason I have
placed it in the genus Stomatia; for in some respects it resembles a Sigaretus, differ-
een the latter genus in haying a groove along the margin of the whorls, as in
aliotis.
Lower Miocene, San Fernando, Trinidad.
ItIl.—Tornatina ecoix-lacryma. (Fig. 3.)
Shell small, cylindrical-oval, nearly smooth, but with fine spiral stria. Spire sunk,
the first whorl projecting as a small papillary knob; whorls slightly concave below
the superior angle; suture channelled. Aperture long and narrow, widening an-
teriorly ; columella with a callous plication.
This shell recalls the secondary Acteonine. It is apparently related to 7. coarctata
and 7. canaliculata, D’Orb., and, perhaps, also to Bulla Lajyonkaireana, Basterot, of
ie Hurppesn Miocene. Only the point of the spire is above the plane of the last
whorl.
From the Upper Miocene of Cumana and Jamaica.
IV.—Nucula Schomburgki, Forbes. (Fig. 5.)
_ (Forbes in Schomburgk’s History of Barbados, p. 565.)
This shell varies a good deal in height and width. The lunule is impressed, but
not circumscribed, nor is there a circumscribed dorsal area. The shell is thick and
nacreous; the teeth of the hinge are pointed.
Lower Miocene, San Fernando, Trinidad.
V.—Leda bisulcata. (Fig. 2.)
Shell ovately trigonal, with numerous concentric ribs, narrower than their inter-
stices ; with a somewhat sinuous elevated ridge running from the umbo to the pointed
rostrum behind; rounded anteriorly with a round groove running from the umbo to
the ventral margin near the anterior angle. Umbones close; posterior dorsal area
Von Koenen—Belgian Tertaries. 501
flat, sloping, striate continuously with the ribs of the disc; no very distinct anterior
area. ‘Teeth very prominent.
This easily distinguished and handsome little species is related to the recent
L. jamaicensis. It is without the large well-defined, anterior dorsal area which that
species seems to have. It is also allied to ZL. ormata, D’Orb.
Upper Miocene, Jamaica.
VI.—Leda incognita. (Fig. 1.) .
Shell transyersely-ovate, compressed, with rounded concentric ribs ; rostrated pos-
teriorly. Dorsal areas broad, distinct, circumscribed by the keels which run from the
umbones to the extremities.
Lower Miocene, San Fernando, Trinidad.
VII.—Macira subovalina. (Fig. 6.)
Shell triangularly sub-oval, transverse, nearly equilateral, rather thin, compressed,
concentrically striate by lines of growth; posterior slope large, and well-defined by
the keel running from the umbo to the posterior end; anterior slope smaller, and less
defined, the carination running from the umbo becoming obscure towards the
extremity.
This belongs apparently to the group of true Mactras, of which the British
M. stultorum is an example, somewhat allied to the present shell.
Lower Miocene, San Fernando, Trinidad.
V.—On toe Betaran TERTIARIES.
By Dr. A. von Kornesn, of the University of Marburg.
INCE Sir Charles Lyell published his most accurate and detailed
paper “ On the Tertiaries of Belgium and French Flanders,” geo-
logists could only differ in their opinions on the facts mentioned by
him. New discoveries have been made in Belgium only in the last
few years; besides the splendid cuttings in the ditches for the forti-
fication of Antwerp, about which I am going to speak afterwards,
there has been found, near Mons, by sinking a well, a thick bed
of lime and limestone at the base of all hitherto-known Belgian
Tertiary beds, containing numerous and well-preserved Tertiary
marine and fresh-water mollusca. The discoverers, MM. Cornet and
Briart, Engineers of Mines, and most zealous geologists, described
very carefully the geological position’ and afterwards the extension’
of these lowest Tertiary beds in Hainaut. In their first paper they
had tried to determine the Molluscan fauna of this basement bed,
after Deshayes’ works; but, out of 150 species, they could name
only 22, and amongst these there are still some very doubtful ones.
These 22 species, belonging to beds superior to the ‘“ Glauconie
inférieure ’’ and to the “Sables de Bracheux” of the Paris basin,
they concluded that the new beds at Mons corresponded in age
with a part of the “Calcaire grossier,” and with the Upper part of
the “ Sables inférieurs”’ (Cuise-la-Motte).
Now the Calcaire grossier and the Sables de Cuise contain a very
rich and well-known fauna, so that I concluded,’ from the small
number of species identical to them and to the beds of Mons, that they
were of different age, rather than of the same, and the fauna of the
1 Bull. del Acad. roy. de Belg. 2me serie t. xx. No. 11 and t. xxii, No. 12.
2 See also Grou, Maa., 1866, Vol. III. p. 174.
3 Zeitschr. d. D. Geol. Ges., xix., pg. 32.
502 Von Koenen—Belgian Tertiaries.
Sables de Bracheux being very small and little known, and bearing
a different aspect, it is not surprising that the correspondence in age
of the Sables de Bracheux with the lime-beds of Mons cannot yet be
proved by Paleontology, whereas Geology indicates it.
Mr. Cornet has written me recently that he has since recognized
his error, and that he is going to rectify it. I have thought it
desirable to make this statement in order to save the honour of
Palzontology, because Mr. Whitaker’ has cited the paper of Messrs.
Cornet and Briart as a proof that it is unsafe to trust to Paleontological
evidence.
I wish, in passing, to say a few words on the ferruginous sand-
stones from Kent, about which Mr. Whitaker 1. c. does me the
honour to cite my opinion.
The commonest and best determinable fossil, or rather cast, in
Mr. Prestwich’s collection was Arca lactea, Lin., which I mistook at
first sight for A. pretiosa, Desh., a species peculiar to the Middle and
Upper Oligocene beds, but after careful examination, I recognized
that it was the recent species, and in this opinion I was confirmed by
the superior knowledge of the late Dr. S. P. Woodward. Besides
this species, I believe there were Terebratula grandis, Scalaria
foliacea, and Emarginula fissura, L., so that I thought it probable
that those beds corresponded with the Red Crag, and in this the late
Dr. 8. P. Woodward, one of the best judges of this matter, was also
of the same opinion. Unhappily I made no list of the determinable
fossils, but I hope Mr. Prestwich, who so kindly allowed me to
make gutta-percha casts from his specimens, will find them out
again, and confirm my statement.
Mr. H. R. Lankester’ has published a paper “‘ On the Tertiaries in
the neighbourhood of Antwerp,” by which he introduces into
English literature the discoveries and observations made by Messrs.
Nyst, de Wael, and Dejardin. He adopts the old division of the
Antwerp beds, by Nyst, Dumont, etc, into:
Sable jaune.
Sable gris.
Sable vert.
Sable noir.
He calls the Systéme Scaldisien, Upper and Middle Pliocene; the
Systeme Diestien, Lower Pliocene, not Miocene, (as I had published
it two years before), and he tries to prove the correctness of this
opinion by the per-centage of recent species in the different beds,
and by the resemblance of the fauna of the Systeme Diestien to that
of the Systéme Scaldisien, and of the Coralline Crag, after the lists
published by Mr. Nyst. Now the list of Mr. Nyst of the fossils
from the Systéme Diestien was not intended as a monograph, but
purely to illustrate a new locality, so that it is not extraordinary if
a number of names are erroneous. On the contrary, it is most
natural that Mr. Nyst should have identified the new-found fossils
1 Quart. Journ. Geol. Soc., 1866, p. 432.
2 Grou. Maa., 1865, pp. 103-6 and 149-52.
Systéme Scaldisien.
Systéme Diestien.
Von Koenen—Belgian Tertiaries. 5038
as much as possible with the well-named fossils of his country,
in this case especially, with the shells from the Scaldisien. On the
other side J must maintain that every Tertiary horizon has as many'
species in common with the succeeding as with the preceding
horizon, that is to say, if they are analogous deposits, and provided
there be no sharp lines of division separating them, either into two,
three, or four periods, according to the author followed, whether
it be Dr. Hoernes, Sir Charles Lyell, or Professor Beyrich. The
division of Professor Beyrich into four periods is in accordance with
the geological distribution of the different beds, and has the advan-
tage that the names of the periods, Hocene, Oligocene, Miocene,
Pliocene, joined to the words Upper, Middle, and Lower, are suffi-
cient to distinguish all the principal horizons of the Tertiaries.
If, therefore, the Systéme Diestien resembles the Coralline Crag
as much as the Coralline Crag resembles the Red Crag, that is not a
reason to put the Systéme Diestien rather into the Pliocene than into
the Miocene. Mr. Lankester proposes to put certain beds of the
Vienna basin, which he concedes to be coeval with the Systeme
Diestien, also into the Pliocene; but in doing so, in order not to
withdraw one of the Antwerp beds from the others, he tears in
two the Vienna beds, which are most certainly identical with the
‘ Faluns de la Touraine,” the type of the Miocene, and older than the
Subapennine and Crag beds, which are the type of the Pliocene.
I must, say at the same time, that the name of Crag noir ought
not to be employed instead of Sable noir or Systeme Diestien,
because these beds do not correspond, either in age, condition,
appearance or contents with the English Crag.
The sub-division of the Sable vert ought to be abandoned, because
the greenish colour is caused only by the weathering of the black
glauconite of the Sable noir, and because the Sable vert lies some-
times below the Sable noir, and contains, moreover, the same fossils,
though generally only in the state of casts, the oysters (Gryphea
navicularis) alone having the shell preserved. In short, Mr. Lan-
kester very correctly states the difference of the Systéme Diestien
from the Coralline Crag, and its identity with beds generally reputed
to be of Miocene age; an identity first announced by me in 1863.”
But I have since then found that Professor Reuss, of Vienna (one of
the best authorities upon Foraminifera, Anthozoa, and Bryozoa), had
already pointed out (in his paper “On the Foraminifera, etc., from
the Systéme Diestien and from the Miocene of the North of Ger-
many), the great analogy between their fauna. The identity of the
Sable noir with the beds of Recken and Winterswyk in the South-
east of Holland has been long ago recognised by Messrs. Nyst and
Bosquet. A few miles from Winterswyk, near Dingden® (north
of Wesel), there appear black marly sands (not passed through by a
well-boring, in a thickness of 120 feet), containing a very rich fauna,
quite similar to that of the Systéme Diestien, but containing, besides
1 About 40 per cent, it appears. 2 Zeitschr. d. D. Geol. Ges. p. 460.
8 See Beyrich, ‘Ueber die Zusammensetzung der Norddeutschen ‘Lertiaerbil-
dungen.”’ Abhandl. der Koenigl. Acad. zu Berlin, 1856,
004 Von Koenen—Belgian Tertiaries.
some other species, peculiar to the Vienna basin and to the Faluns,
such as Murex aquitanicus, Grat., M. Parischi, Hoernes, etc. About
20 German miles to the east from this place, there are, in numerous
places, near Berssenbriick, north of Osnabriick, black sandy and
marly clay-deposits of about 160 feet in thickness, with the same
fossils repeated. About 30 German miles further to the east-north-
east, the black clay once more appears, near Liineburg, with a
similar fauna, and again, about 15 miles from this, a yellow marl,
with nearly the same fossils, is met with also near Giihlitz, near
Terleberg or Wittenberge (on the railway, mid-way between Berlin
and Hamburg). This is the farthest known point of this Miocene basin
to the south-east. From thence the Miocene beds spread over the
western part of Mecklenburg, where they sometimes occur as hard
sandstones, with casts of marine shells (Bokup Reinbeck).’ In the
western part of Holstein, Schleswig, and on the Isle of Sylt, black
micaceous clay-deposits appear frequently, with a similar but rather
poorer fauna, somewhat more approaching that of the Coralline
Crag. In the eastern part of Holstein and Mecklenburg, erratic
blocks are frequently met with, containing a richer and older fauna,
that is to say of Lower Miocene age.
There has been apparently no direct communication with the
Miocene sea in Bohemia and Galicia, the extension of which into
Upper Silesia has been explained and illustrated by Professor
Beyrich, in his most important work already referred to.
So far for the distribution of the Miocene beds in the North
of Germany. As to the fauna, there is yet little known; it is
described by Professor Beyrich in his still unfinished work, and in
some lists by Mr. Semper. I can only assure English geologists
that the fauna much more resembles that of the Vienna basin, and
of the Subapennine formation, than that of the English Crag, and of
the Systéme Scaldisien, near Antwerp. It seems quite natural that
the Miocene of the North of Germany should contain more Sub-
apennine forms than the Vienna basin, because there has clearly been
a migration of many species from the North to the South, as is now
generally accepted by most geologists.
Another paper, “On the Kainozoic Formations of Belgium,” ® has
been published last year by Mr. Godwin-Austen, against which
Mr. Lankester, Mr. Searles Wood, and others have more or less
energetically remonstrated in different papers, especially with regard
to some points advanced as to the formation of the English Crag.
Mr. Searles Wood, with his long years of experience of the Crag-
beds, did not think it possible to admit the theories and many of the
observations as to the state and condition of the Crag-sea, as ex-
plained by Mr. Godwin-Austen. There cannot be any very strong
opposition offered to such a high authority ; but as I find that Mr.
Godwin-Austen has published a number of observations, made at
Antwerp, during his short stay, which have not yet been disputed,
1 See Koch in Zeitschr. d. D. Geol. Ges. vi. pp 22 and 269; viii. p. 249. Meyrin
Zeitschr. d. Deutsch. Geol. Ges. iii. p. 411.
* Quart. Journ. Geol. Soc., London, vol. xxii. p. 228. 1866.
Von Koenen—Belgian Tertiaries. 505
I venture to offer a few remarks thereon. I have visited Antwerp
upon five separate occasions, in three different years, and have
always seen new cuttings in the main ditch at the forts, and in the
excavations for a new harbour between the town and the Fort
d’Austruweel. I have stayed there altogether above two months
collecting a large quantity of fossils, mostly from the untouched
beds, and as my observations differ in so many parts from those of
Mr. Godwin-Austen, I think it necessary to call attention to, at least,
the more important ones, on which he bases his theories. It is most
unfortunate that he does not follow in his paper the divisions of the
Tertiaries of any of the authors who had already described these
beds; and that he does not himself explain where he intends to
make these divisions, nor the names by which they shall be called.
It is impossible, therefore, to say much about this point; but there
are certainly more than two Tertiary horizons. The Barton clay
does not correspond in age with the “Rupel clay” (which Mr.
Godwin-Austen calls Rupellien clay), as stated by him (p. 234, op. cit.).
The Tertiary beds of Cassel, Luithorst, Freden, and Diekholz, which
he puts into the Upper Kainozoic (p. 241), are older than the Faluns
de la Touraine, and coéval with the Grafenberg, near Diisseldorf,
and the Sternberg sandstones which he puts (p. 237) into the
Tongrien ; but the Tongrien of d’Orbigny is not well defined. That
of Dumont and that of Ch. Mayer is older than all these. The
Faluns of Touraine and most of those of Bordeaux are older than
the Crag and the Cotentin according to the opinion of all other
geologists, whereas Mr. Godwin-Austen says they were synchronous
(p- 289), but without giving any reason for this opinion.
This classification, then, of Mr. Godwin-Austen’s, invalidates his
otherwise valuable map, because so many different periods are con-
founded together. As to his theories about the condition of the
Crag-sea area. and the origin of its deposits, I cannot agree with
him at all, because I have observed many important facts differing
very much from those stated by him.
For example, he considers the “Sable noir” as coéval with the
Coralline Crag, but thinks it impossible to separate these from the
Red Crag and from the Scaldisien (called in Mr. Godwin-Austen’s
paper “Scaldésien”), because this should ‘contain only dead and
drifted shells,” (p. 233), ““wholly extraneous to it, belonging to all
regions of depth, and all periods of the Crag formation” (p. 238),
The difference of the fauna of the “Sable noir” and of the Coral-
line Crag is explained by him (p. 238) “by the differences which
result from depth and condition of sea-bed,” and (p. 241) “taken
together both form a complete marine fauna, representing a greater
range of sea-zones.” The Systeme Diestien was deposited in thirty
to forty fathoms (p. 283), in a maximum thickness of four metres
(p. 283), The Systeme Scaldisien was (p. 282) “heaped up under
inconsiderable depths of water,” and formed about six feet, but at
no place exceeded probably eight feet ;” it was a dead shell gravel ;
“not one of the shells had lived where it is now found.”
Now I can assure Mr. Godwin-Austen that the thickness of the
506 Von Koenen—Belgian Tertiaries.
different beds is much more considerable. The “Sable jaune”
attains, near Deurne, a thickness above fifteen feet; the “Sable
gris,” in the new harbour (or dock?) between the town and the Fort
d’Austruweel, as far as I] remember, about twice as much; the
“Sable noir; attains six metres near the fort (according to the
section of Captain Déjardin).
I have collected in the Scaldisien beds between Deurne and the
Fort d’Austruweel the following species of bivalve shells, in a
splendid state of preservation, partly even with the ligament pre-
served :—JLangula Dumortierit, Nyst., Terebratula grandis, Blum.,
Ostrea edulis,* Pecten tigrinus, Miull., Pecten opercularis, L., Modiola
sericea, Goldf.,** Pinna sp., Leda sp.,** Nucula sp., Astarte Basterott,
La Jonk.,* Astarte Omalii, La Jonk.,** Astarte Burtini, N., Oyprina
islandica, L., C. rustica, Wood,* Isocardia cor, L.,** Artemis exoleta,
Lnucina borealis, L.,** Axinus sinuosus, Sow., * Tellina Benedenii, Nyst.,**
Solen, two sp., Mya truncata? L., Panopea Menardii? Glycimeris
angusta, L., and many others. My collection and my books being
packed up, on account of leaving Berlin in order to settle at Mar-
burg, I am obliged to write down from memory only those species
about which IJ am quite sure. I mark by asterisks the species which
were rather common bivalves.
I think there can be no doubt, first, that these species have lived
where I found them ; secondly, that some of them indicate a much
greater depth of water than Mr. Godwin-Austen gives credit for
in the Systeme Scaldisien ; and, thirdly, that they are not washed
out from the Systéme Diestien, in which, with few exceptions, they
do not occur at all.
I have indeed seen, near Deurne, some Scaldisien beds, with
numerous broken shells, which undoubtedly were “‘terrains remanies,”
but only by former fortification-works. A dead-shell gravel might
also be seen in a few places, but I have never found any shell in it
which was not common in the finer sandy beds in the neighbourhood.
Some beds near Deurne, several feet thick, consisted only of frag-
ments of Pecten grandis, P. striatus, P. opercularis, etc.; but the
shells had been crushed at that very place, the pieces of every shell
lying flat together ; there was no clay or sand there to protect them
against the pressure of the overlying beds. 'The deepest cutting I
have seen was in the before-mentioned harbour (or dock) near the
Guano-magazine, north of the town. There was at the bottom,
still, fine grey sand with numerous specimens of Azinus sinuosus,
and Modiola sericea, and other shells, always having both valves.
Somewhat higher I have found several Panopea, also, with both
valves, and still higher the Mya, oysters, Isocardia, etc., mostly with
both valves.
It is very probable that some Scaldisien beds, particularly of the
Sable jaune, in the main ditch, indicate shallow water; but others,
particularly of the Sable gris, undoubtedly have been deposited in a
similar depth as the Sable noir, so that the difference of fauna
between the Scaldisien and the Diestien caunot be explained by
difference of depth. I do not think that I have collected a single
Von Koenen—Belgian Tertiaries. 507
species in the Systéme Scaldisien, near Antwerp, that does not occur
in the English Crag. There is, therefore, no reason to disbelieve
the geological and paleontological evidences, that the Systéme Dies-
tien is older than the Crag, and that the Systeme Scaldisien is the
exact equivalent of the Crag.
If the Sable jaune (or Sable rouge) resembles more in its
fauna the Coralline Crag than the Red Crag, to which it is referable,
by reason of its being the upper member of the Scaldisien, that
may be explained by the different condition and structure of the
Red Crag, which was deposited, apparently, in a more agitated or
shallower sea.
As to the Systéme Diestien I have explained my views before.
The scheme, therefore, is this :—
ENGLAND. BELGIUM. | GERMANY.
Z
| Red Crag. Systéme { Sable jaune.
5 Coralline Crag. Scaldisien. ( Sable gris.
i fe ee OS NS eee eee
ol .
a Systéme Sable noir | Schleswig.
S Dison su and Dingden, Berssenbriick,
= Boldérien ) Iron-sands. | Liineburg, Giuhlitz, ete.
= Cassel, Freden, Biinde,
a Elsloo, near Maestricht. Crefeld.
=) Sternberg, Wiepke.
a
a
o = Hempstead series Systéme Rupélien. Hermsdorf, Séllingen.
3 = Bembridge series. Systéme Tongrien, super.| Stettin, Cassel, Bunde.
=
Oo
Headon series. . gietcte sip Lattorf, Westeregeln, Urse-
Brockenhurst. Systeme Tongrien, inf. berg, Helmstidt, Binde.
| Lower.
In conclusion, I may say it was most instructive to me to see
the different species distributed in the different places, and how
each had its peculiar locality. Thus, I remember a place where, in
the Sable noir, below the Pectunculus bed, there were large numbers
of bivalve Panopea to be seen, though very difficult to be got out
entire. In another place, near the railway, I collected, at least,
fifty examples of Pecten Brummelii, Nyst., having a diameter of about
four inches, a species reputed very rare by Belgian geologists. It
is very unfortunate that the fortification-works are now finished.
Last year I could not find a single specimen worth picking up. Let
us hope that the fortress of Antwerp may soon become too small for
the requirements of Belgium, and that there will be new ditches
made around the city to yield future collectors additional examples
of these beautiful fossil shells and corals.
008 Brown—Aretic Deposits, Fifeshire.
NOTICES OFF. - VEO S-
——=
J.—On tor Arctic SHELL-cLay or Erte anp Erron, Frresurre,
VIEWED IN CONNECTION WITH OUR OTHER GLACIAL AND MORE
rEcENT Deposits. By the Rev. Tuomas Brown, F.R.S.E.
[From the Transactions of the Royal Society of Edinburgh, vol. xxii. part iii.]
FTER describing in detail several sections in the two localities,
the author, by combining the information derived from them,
gives in serial order the various deposits, and examines the evidence
they supply as to climate and the relative height of sea and land.
In descending series the beds are—
1. The Blown Sand and Raised Beaches.—The blown sand is in
some places from twenty to thirty feet thick, and contains several
beds of peat of various thicknesses, some of them containing large
numbers of ‘land and fresh-water shells of species now living in the
district. The so-called raised beach consists of shingle, sand, and
shells, arranged in a confused manner. It was probably deposited
on the shore while the sand was forming beyond high-water-mark.
It is occasionally eighteen feet thick. The evidence that it is a true
raised sea-beach is not decisive.
2. Sands and Clays with Scrobicularia.—This consists partly of
about a foot of fine clay with numerous specimens of Scrobularia
piperata in the position in which they lived. The tide runs further
up the stream than where this deposit occurs, but the level of high-
water-mark is at least fourteen feet below the clay bed. In the
brick clays between Stirling and Bridge of Allan, in which skeletons
of whales have been found, Dr. McBain has obtained specimens of
Scrobicularia and also at Portobello, and both these clay beds are at
the same height above the present level of the sea as at the Hlie
deposit. Below the clay there is about six feet of alternating sandy
and clayey layers, containing the same species of mollusca as occur
on the shores of the Forth at present, showing the climate to have
been the same as now.
3. The submerged Forest.—This is seen on the shore passing out
into the sea. It is four feet in depth, and consists of a mass of peat,
in which willow and hazel, and especially hazel-nuts, were found,
with other seeds, mosses, and abundant remains of Arundo Phragmites.
These plants indicate a climate identical with the present.
4, High-level Gravel and Sand.—The beds of this stage occur at
considerable heights all over the surface of the country, and are
entirely destitute of fossils. In some of the gravels are found
angular patches of fine sand, which the author supposes to have been
frozen masses of sand transported with the gravel; and, if so, giving
the first indication in the descending series of the glacial cold.
In the Fife deposits there is, below this gravel, an unconformity
which Mr. Brown believes to represent the period during which were
deposited—1st, the beds of Fort William and Caithness, investigated
by Mr. Peach; 2nd, the Clyde beds, described by Mr. Smith; and
Brown—Arctic Deposits, Fifeshire. 509
3rd, those of Aberdeen, to which Mr. Jamieson has devoted his
attention. These indicate an increasing degree of cold which reaches
its climax in the next stage.
d. The Arctic Shell-clay.—This is a fine clay in which the following
shells have been found. The names are given on the authority of
Dr. Otto Torell.
Buccinum cyaneum. Yoldia hyperborea.
Natica grenlandica. Y., nov. sp.
Turritella erosa (polaris). Astarte compressa.
Pecien grantlandicus. Nucula inflata.
Crenella decussata. Dacrydium vitreum.
C. nigra. Thracia myopsis.
C. levigata. T., nov. sp.
Leda truncata. Tellina proxima.
L. minuta. Saxicava rugosa.
Not only are all these species now found in arctic seas, but the size
of those species which have a wider distribution southwards corres-
ponds with the specimens of them now living in the seas of Greenland
and Spitzbergen. The Clay bed is more than forty feet above high-
water-mark ; the shells are evidently in the Clay in which they lived :
and as they are all deep-water species, the level of the land must
have been at least 150 or 200 feet lower than it is now.
6. The Boulder-clay.—This well-known deposit, both at Errol and
Khie, is beneath the Arctic Shell-clay ; but, from an examination of their
relations, the author believes that, as a whole, they were deposited
simultaneously, and that the fossils enumerated represent the life of
the Boulder-clay period.
The author considers that these Fife deposits may form the
starting point for a more rigorous classification of the superficial
beds throughout Scotland. W. C.
I.—On a New Crepuazasprp. By E. Ray Lanxesrer,
Christ Church, Oxford.
[British ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE. DUNDEE,
SecTION C. GroLoey.]
R. Lankester exhibited a diagram of the head of a Cephalaspid,
fragments of which had been described by Agassiz as Plectrodus
pustuliferus. It was remarkable for its long cornua, minute pustular
ornamentation, and the dentation of its outer margin. It was pro-
bably an Auchenaspis, but the posterior ‘neck-plates ’ were deficient.
Specimens of the head had been obtained by Mr. Lightbody of Ludlow
and Dr. Grindrod of Malvern. Mr. Lankester exhibited a diagram of
a restored Cephalapis, and noticed the existence of a series of scales
forming the broad ventral surface of the body and tail of this genus
of fishes. He also noticed the thickening of the margin of the head-
shield and the ornamentation of a part of its under surface, showing
that this particular part of the concave surface was superficial like
the whole of the convex surface, and not covered in by a lower jaw
or other plates.
510 Whitaker—Surface- Geology of London.
REVIEWS.
I.—Note on THE SuRFACE-GrOLOGY oF Lonpon; wits Lists oF
WELLS AND BorInGS, SHOWING THE THICKNESS OF THE SuUPER-
FictaL Deposits. By Wriiu1am Wurraker, B.A. (Lond.) F.G.S.
of the Geological Survey of England.
[Extracted from the Appendix to the Report of the Medical Officer of the
Privy Council for 1866. ]
T is an encouraging ‘ sign of the times’ when the Medical Officer
of the Privy Council avails himself of the aid of the Geologist in
making his report on the Health of the City of London.
The newspapers of the last two years have revealed to us many
shocking cases of wells in the metropolitan area which were polluted
by sewage to an alarming extent. ven where wells are made in
porous strata (such as Alluviuin, Brick-earth, Gravel, and Sands),
the quantity of “‘ Made Ground and Soil,” is often equal to half, and
sometimes to two-thirds or more, of the entire depth of the well.
Out of a list of 90 wells, of ascertained depth, 5 were between 40
and 50 feet; 21 were between 30 and 40 feet ; 24 were between 20
and 30 feet, whilst 40 were only from 9 to 20 feet in depth. When,
notwithstanding all the efforts to the contrary, the sewage of a popu-
lation like London is daily affecting the subsoil to a greater or less
extent, it stands to reason that all superficial sources of water-supply
within the town-area must be seriously vitiated by ancient cesspools
and other unremoved nuisances which yet haunt many of the poorer
suburban quarters of our great city.
In addition to the Tabulated List of Wells in London, there are
15 Tables comprising upwards of 206 ascertained Borings along the
various lines of the Metropolitan Main Drainage Works. ‘The col-
lecting and tabulating such data as these, whether it be done by the
Officers of the Geological Survey, or by the Engineers, deserves the
highest commendation.
We earnestly hope the Director of the Geological Survey may
have his hands strengthened so that he shall be enabled to send one
of his staff to visit every section and excavation of any extent, and
carefully to record the details of the same before it disappears for
ever behind brick-work, or is covered with vegetation. How many
fine opportunities of obtaining sections in difficult districts have thus
been lost! In conclusion, we would express our conviction that
Geology should not only form a part of the training of every Civil
Engineer, but Contractor’s Clerks and Assistants have in many in-
stances shown that they could, if properly trained, make excellent
geological observers in the field.
Tl.—E.ementary Gronocgy anp Enementary Minerarocy. By
J. R. Gregory. London, 1867.
Bigae the above titles Mr. Gregory has arranged in book-cases
a series of specimens of rocks, fossils, and minerals, with a
view of affording the student or traveller the advantage of readily
;
Forbes—The Microscope in Geology. dll
acquiring a practical knowledge of the more common forms with
which he ought to be acquainted, or is likely to meet with, as well
as to form a useful aid to teachers in public or private schools who
may desire to impart to their pupils a knowledge of the elements of
geology and mineralogy. ‘The geological series comprises two
volumes, each containing twelve specimens, neatly arranged and
named with their geological position and localities, one of British
rocks, the other of British fossils. 'The mineralogical series is also
contained in two cases, one comprising the earthy minerals from
which many important and useful preparations are extracted for use
in the arts and manufactures; the other contains the mineral ores
from which the metals in general use are extracted. Appended to
each volume is a brief description of the different specimens, as well
as some general and introductory information useful to those com-
mencing the study for the first time. Thus, under ‘ British rocks,”
the classification and the chief subdivisions are given; and under
“Metallic minerals,” the principal characters of minerals and terms
used in mineralogy are noticed. Hach volume is complete in itself,
and the cheap price at which they are produced ought to guarantee
for them an extensive circulation.
IiJ.—Tset Microscort in Gronoey.
NDER this title we find a very interesting article in the
*“ Popular Science Review” (for October, p. 355), by David
Forbes, F.R.S., which so entirely relates to our own special study,
that we trust we shall be excused for giving an unusually long
notice of it: we only regret being unable to present our readers
with copies of the two beautiful plates illustrating the “ Microsco-
pical structure of Rocks,” which accompanies it. After pointing out
the indispensable nature of microscopic inquiry, in order to solve the
true character of rock-masses, the author proceeds to describe the
best method of preparing sections of rocks of the needful trans-
parency for microscopic investigation.
«The examination,” says Mr. Forbes, “of such a rock-section
enables a mineralogical analysis to be made, even of the most com-
pact and apparently homogeneous rock, and generally leads to the
discovery of other mineral constituents previously unsuspected, from
their being invisible to the eye, and also, as Sorby has observed,
allows those minerals, formed at the time of solidification of the
rock, to be distinguished from such as are the products of subsequent
alteration.
Arranging rock species according to their structure, it will be
found that most rocks fall naturally into one or other of two great
classes—
I. Primary orn Ervuptive Rocks;
II. Sxconpary or Sepimentary Rocks ;
and it will be seen that the microscope is of special value when
applied in cases where the external appearance renders it doubtful
as to which of these classes a rock may pertain.
Or
12 Forbes—The Microscope in Geology.
The terms primary and secondary are here used quite indepen-
dently of geological chronology. Primary rocks (of all ages) might
be called ‘‘ingenite or subnate rocks” (7.e. such as are born, bred, or
created within or below), whilst the term “‘ derivate rocks” would
be appropriate for the latter, since directly or indirectly they are all
derived from the destruction of the former.
I. Primary on HRuptive Rocks.
This class includes rocks which have made their appearance in
many, if not in all epochs, from the most ancient to the most recent,
from the old granitic outbursts to the eruptions of the now active
volcanoes; and if, as is now generally admitted, the earth be re-
garded as having been once a molten sphere, the consolidated origi-
nal crust of the globe would pertain to this class of rocks.
Mineralogically they consist of crystallised silicates, with or
without free quartz, and usually containing many other minerals
in minor quantities, especially metallic compounds, as magnetite,
titanoferrite, iron pyrites, etc, which last are frequently present in
so minute a quantity as only to be detected by the microscope.
Whatever be their geological age, or from whatever part of the
earth’s surface they be taken, the microscopical inspection of such
rocks shows immediately that they possess certain general and
definite structural characters, distinguishing them at once from all
other rocks.
The mineral constituents of such rocks are seen to be developed as
more or less perfect crystals, at all angles to one another, thereby
indicating that the entire mass must have been one time ina state of
liquidity or solution (aqueous or igneous), sufficient to allow of that
freedom of motion absolutely essential to such an arrangement of
the particles.’
The microscopic examination already made of many hundred
sections of eruptive rocks, differing widely in geological age and
geographical distribution, shows that in all rocks of this class,
whether of the most compact, hard, and homogeneous appearance, or
occurring in the softest and finest powder, like the ashes and dust
frequently thrown out by volcanoes ; a similar crystallised arrange-
ment and structure is present and common to them all. Lavas,
1 These rocks are indiscriminately called volcanic, igneous, plutonic, crystalline,
etc. The term crystalline, although characteristic of these rocks, is not exclusively
so, and is consequently less appropriate ; many normal sedimentary beds, as rocksalt,
gypsum, etc., are perfectly crystalline, and others when altered by metamorphic
action, become more or less so,
2 Experiments show that analogous structure can be produced by at least three
different methods, all of which, however, agree in the necessity of the mass being in
a state of complete liquefaction previous to crystallisation ; from—
1. Their solutions in water or other menstrua.
2. Aqueous fusion or melting of hydrated bodies in their water of crystallisation.
3. Igneous or hydro-igneous fusion. }
Crystalline structure may nevertheless develop itself by a molecular movement in
solid bodies without change of external form or previous liquefaction; as will be
hereafter explained, this is frequently the case in nature. The structure so developed
is, however, very distinct from the crystallisation after liquefaction, characteristic of
the eruptive rocks.
Forbes—The Microscope in Geology. 518
trachytes, dolerites, diorites, porphyrites, syenites, granites, etc., all
possess the same general structural features, serving to distinguish
the eruptive rocks as a class from all others.
In the examination and discrimination of the minerals which
compose these rocks, especially when close-grained, the microscope
is quite indispensable, since without it no such enquiry could be
attempted. In these examinations the assistance of polarised light
is most valuable; but the space, unfortunately, only allows of a
mere mention of its application. In distinguishing dolerites from
diorites, when fine-grained (as is often of considerable geological
importance), the fibrous structure of the hornblende of the latter is
generally so well developed, even when present in very minute
quantity, as to distinguish it readily from the augite of the former,
which possesses no such structure. Even in the case of Uralite,
a mineral characteristic of certain porphyritic rocks, which has the
external form of augite, although its chemical composition is that of
hornblende, the fibrous structure characteristic of hornblende is
distinctly visible. The microscopic structure of some minerals,
however, varies with their origin; thus Sorby has shown that the
structure of augite, and some other minerals in meteorites, is quite
distinct from that of the same minerals occurring in eruptive rocks,
and demonstrated, in a very striking manner, how the study of such
peculiarities is likely to clear up the mystery in which the origin of
these bodies is involved.
When, as is often the case, especially with translucent, colourless
minerals like quartz, leucite, calcite, felspar, etc., the appearance
presented under the microscope is alike, their optical properties and
the use of polarised light afford the means of distinguishing between
them with certainty ; as, also, in the event of one substance being
present under two forms, as calcite from aragonite, monoclinic from
triclinic felspars, etc. In a similar manner, the structure, whether
crystalline or vitreous, is determined, and valuable information
obtained, elucidating the mode of formation and origin of the rocks
themselves.
The alterations produced in eruptive rocks subsequent to their
solidification, by the action of water, atmospheric, or other agencies,
are studied with advantage under the microscope.
In a section given, the skeleton of labradorite is seen remaining as
evidence of the original crystallised structure, whilst the interstices
contain the products of the alteration of the more easily decompos-
able augite, the structure of which is nearly obliterated, and part of
its lime converted into carbonate. The rock in question is the
so-called ‘“‘ white horse” of Staffordshire, found imbedded in, or
breaking through the Coal-measures, which are frequently burnt or
altered at points of contact with this rock, which itself often has the
appearance of a whitish clay. The origin of this rock, whether
sedimentary or igneous, was disputed until the more recent geologi-
cal and chemical examinations of it have proved satisfactorily its
identity with the Rowley basaltic rock, very similar to that of
Poukhill.
VOL. IV.—NO. XLI. 33
O14 Forbes—The Microscope in Geology.
Another section of a crystalline slag, produced in silver smelting,
is given for the sake of comparison with the structure of erup-
tive rocks. In formation it is so nearly identical with what is seen
in sections of more felspathic basaltic rocks, the mass of which
consists of a framework of interlaced crystals of labradorite with
the interstices filled wp with the other mineral constituents confusedly
crystallised, that this section might easily be mistaken for such.
The Rowley rag, when fused and very slowly cooled, presents a
similar appearance; and, in general, the structure of crystalline
slags presents many features in common with that of ordinary
eruptive rocks.
Before proceeding to the next class of rocks, the discovery by
Sorby of the numerous minute fluid cavities in the quartz of granites
should be alluded to, as proving the great value of the microscope
in the study of these rocks. The result of this gentleman’s re-
searches! proves that granites have solidified at a heat far below the
fusing points of their constituent minerals, and at such a pressure as
to enable it to entangle and retain a small amount (+ to 4 per cent.)
of aqueous vapour, which naturally must have been present during
its liquefaction. 'The presence of these fluid cavities in the quartz
of granite was immediately blazoned forth as proof positive of the
non-igneous origin of granite ; whereas, if Mr. Sorby’s memoir had
actually been read, it would have been seen that he had found fluid
cavities, perfectly identical with those in granite, not only in the
quartz of volcanic rocks, but also in the felspar and nepheline
ejected from the crater of Vesuvius, and that the presence of fluid,
vapour, gas, and stone cavities, are common both to the volcanic
quartz-trachytes and to the oldest granites; and the inference drawn
by Mr. Sorby, from the results of his researches, is that both these
rocks were formed by identical agencies. He therefore classes
them together under one head as rocks of similar origin.’
Il. Seconpary orn SEDIMENTARY Rocks.
The rocks pertaining to this class are all, directly or indirectly,
formed from the breaking up, or débris, of previously existing
rock, and, for that reason, might, as before-mentioned, not inappro-
priately be termed derivate rocks. When found in the normal state
of sedimentary deposition, they may be conveniently subdivided
into—
1. Rocks formed of the immediate products of the breaking-up of
eruptive rocks.
1 Quart. Jour. Geol. Soc., vol. xiv. pp. 453-500.
2 These researches tend to confirm the theory of the igneous origin of granite and
eruptive rocks in general, It must not be forgotten that by ¢gneous action, as used
by the Plutonist, was always understood the action of heat as developed in volcanoes
(the study of which was the basis of the theory itself), in which the agency of
water was always recognized. Nearly half a century ago, Scrope not only insisted
on the important part played by water in volcanic action, but specially pointed out
the difference between such volcanic fusion and ordinary melting. The term hydro-
igneous action might not be inappropriate for such, but hydro-thermalism does not at
all express what is intended. ‘The idea of a true dry fusion in nature exists only in
the brains of the ultra-Neptunist or lukewarm hydrothermalist.
Forbes—The Microscope in Geology. d15
2. Rocks built up of the more or less rounded or angular débris
of previously existing sedimentary or eruptive rocks.
3. Rocks composed of mineral substances extracted from aqueous
solution by crystallisation, precipitation, or the action of
organic life.
1. Rocks composed of the immediate products of the breaking-up of
eruptive rocks.—The little attention paid by geologists in general to
the study of rocks of this class, has introduced the elements of con-
fusion into many of their enquiries, and frequently has led to very
erroneous opinions being formed as to the nature and origin of
certain rocks, which could never have been entertained had micro-
scopic investigation gone hand in hand with field observation.
Rocks of this class may either be of subaérial or subaqueous
origin ; in the former case, for example, volcanic ashes may have
been deposited as beds on the surface of the land, and afterwards
been covered by lava streams poured out over them; or, from having
been depressed below the sea level, may have had sedimentary beds
of aqueous origin subsequently superposed on them.
When of subaqueous origin, as is by far the most common case,
subaérial or subaqueous outbursts may force into the sea eruptive
rocks, which, being at once broken up into a state of division more
or less fine, in proportion to the greater or lesser cooling power of
the watery mass in immediate contact, may be spread out into beds
by the action of the waves: the texture of these rocks may vary
from that of the coarsest breccia down to the finest mud, and, as is
usually the case, such deposits may present themselves as alternating
beds of coarse and fine character. Upon the consolidation of such
formations, rocks are formed, identical in chemical and mineralogical
composition with the original eruptive rock from which they were
derived, and which, particularly when close-grained, often present an
external appearance so like the original rocks as to be frequently
undistinguishable from them by the naked eye; in such deposits it
is often easy to pick out specimens having all gradations in appear-
ance from the above described down to such as would be attributed
to the consolidation of mere detrital mud.
No wonder, therefore, if the field geologist finds himself bewildered
“under such circumstances, and inclined to settle down in the comfort-
able belief of the transmutation or transition of sedimentary rocks
into eruptive, etc. ; even the chemist feels puzzled, when he finds
that a rock taken out of apparently normal stratified deposits has the
same chemical composition with one of undoubtedly intrusive nature.
The microscopic examination, however, soon shows that, however
similar the external appearance of two such rocks might be, their
internal structure is totally different ; showing in the primary rock
the crystallised structure and arrangement previously described,
whilst the secondary rock is resolved into a mere agglomeration of
more or less broken fragments of the same minerals constituting the
former. In beds formed from the consolidation of volcanic ashes,
the microscopic examination occasionally affords evidence as to
whether such ashes had been deposited on land, or had fallen into
water.
O16 Forbes—The Microscope in Geology.
2. Rocks built up of the more or less rounded or angular debris of
previously existing sedimentary or eruptive rocks——Where sufficiently
coarse-grained, these rocks constitute ordinary conglomerates, brec-
cias, grits, sandstones, etc., and are easily analysed by the eye; but
if fine, as shales, slates, etc., the microscope must be appealed to, in
order to resolve them into their constituent mineral or rock particles,
and by this means it will be seen that even the most compact and
homogeneous specimens are a mere aggregate of more or less rounded
and water-worn grains of quartz, weathered felspar, mica, chlorite,
soft and hard clays, clay slate, oxide of iron, iron pyrites, carbonate
of lime, fragments of fossil organisms, etc., arranged without any
trace of decided structure or crystallisation, even when the highest
powers of the microscope are employed in their examination. The
physical structure and optical properties of the mineral components
enable them, however, to be recognised with great certainty, even
1
when in grains of less than = of an inch in diameter.
A section is given of a fine-grained (uncleaved) Silurian clay slate
from Sorata, in Bolivia, magnified 400 linear. This rock is com-
posed of irregular grains of quartz sand, weathered felspar, and
water-worn mica, along with specks of oxide of iron and iron pyrites,
all promiscuously mixed.
In the case of roofing slate, however, the microscope shows that
the constituents, instead of being distributed at random throughout
the mass, possess a definite arrangement, as may be seen in a.
section of Lower Silurian roofing slate from the Festiniog quarries,
where they are disposed in parallel lines, thus constituting lines of
weakness or the cleavage of the slate. The researches of Sharpe and
Sorby have conclusively proved that this has not resulted from any
chemical or crystalline action whatsoever, the particles being in
themselves perfectly unaltered; and that the arrangement is solely due
to the effects of pressure, applied at right angles to the structure
itself, thereby causing an elongation or flattening out of some, along
with a sliding movement of other of the particles. The amount of
compression to which an ordinary roofing-slate has been subjected
in one direction, has been calculated, approximating from the elong-
ation or distortion of the particles, to be about equal to one-half of
its original volume.
Besides the cleavage structure, so produced by the compression of
rocks whilst in a more or less plastic state, Mr. Sorby has shown that
another system of minute jointing may also be present in these rocks,
the serrated edges of which, as seen by the microscope, prove it to
have been the result of force applied to the rock subsequently to its
having been in a perfectly rigid condition.
Rocks of this class, when somewhat close-grained and much in-
durated, have not unfrequently, from their external appearance, been
mistaken for intrusive rocks: thus an Upper Oolitic, highly-inclined
shale-bed, was mapped by D’Orbigny as an eruptive greenstone ; but
the microscopic structure proves the contrary most conclusively.
3. Rocks composed of mineral substances extracted from aqueous solu-
tion by erystallisation, precipitation, or the action of orgamec life.—
Forbes— The Microscope in Geology. 517
Under this class are included most beds of gypsum, rock-salt, and
other saline bodies, as well as travertine, silicious sinter, flint, infu-
sorial slates and earths, limestones, etc., many of which have been as
yet but very superficially examined.
In the microscopic investigation of such rocks as owe their origin
to the developement of organic life, very considerable progress has
been made, with correspondingly important and interesting results.
As early as 1836 Ehrenberg proved that large rock masses were
built up of the carapaces of minute silicious infusoriz, and more
lately Sorby has done good service by his investigation of lime-
stones: these he has proved not to have originally possessed any
crystalline structure whatsoever, but to have been deposited as mere
mechanical aggregates (aptly termed by him, organic sands or clays)
formed of the débris of calcareous organisms, which admit frequently,
not only of being recognised, but of having their relative proportions
determined. The comparison of the microscopic structure of the
organisms in Chalk, with those now forming in the depths of the
Northern Atlantic Ocean, indicates that there is an immense deposit
now in the course of formation, quite analogous to what had pre-
viously taken place in the seas of the Cretaceous period; and the
same able observer has shown that the reason why certain calcareous
organisms are found so well preserved, whilst others had disappeared
or become entirely disintegrated, was from the carbonate of lime in
the first being in the form of the stable calcite, whilst in the latter it
was present as instable Aragonite.
When a calcareous. rock has undergone cleavage, the microscope
shows a distortion of its particles and organisms, just as in a cleaved
slate, though in a much less degree ; the measurement of such distor-
tion serves as a basis for estimating the amount of compression
undergone.
With the exception of having briefly referred to the alterations in
igneous rocks, subsequent to their solidification, and the cleavage of
sedimentary beds, all the classes of rocks treated of have been con-
sidered in their normal or unaltered condition. It remains now to
direct attention to the use of the microscope in the study of subse-
quent alteration or metamorphism of rocks.
Many sedimentary beds become more or less indurated, at points
where they are cut through by eruptive dykes; thus the Coal-shales
and clays of Staffordshire are found altered into a hard rock with
conchoidal fracture, or even into porcellanite, when in immediate
contact with basaltic dykes. An examination shows no change in
mineral or chemical composition beyond the expulsion of the water
always contained in such beds, and sections of such rocks are often
seen to be quite identical in structure with those of common stone-
ware made from the same clays, the only difference being that the
latter is usually more porous from not having been submitted to the
pressure which rocks baked in siti would experience.
The alteration of rocks produced by infiltration may or may not
be accompanied by chemical changes. Thus a section of Calcareous
grit often shows that the calcite filling up the interstices between
518 Forbes—The Microscope in Geology.
the grains of sand has been merely deposited from a solution of
carbonate of lime which has percolated through it, and in otherwise
unaltered limestones it is common to find microscopic veins of calc-
spar, due to minute cracks or fissures, filled up in a similar manner.
Frequently however, such infiltration is, accompanied by an entire
change in the chemical compasition of the rock itself; thus the beds
of Cleveland ironstone have been proved by Sorby’s microscopical
researches to have been originally shell-limestones converted into
_carbonate of iron by the action of ferruginous solutions, the frag-
ments of the original shells being still distinguishable in all stages
of conversion ; in the same manner he has proved the Magnesian
limestones of the Carboniferous and Devonian ages, as well as the
Permian dolomites, to have been originally common limestones, or
aggregations of organic débris, the particles of which, by the use of the
microscope, can be traced back to their original unaltered state, from
which they have been changed by the action of magnesian solutions.
The metamorphism of rocks produced by gasolytic action, as, for
example, carbonate into sulphate of lime, etc., has, as yet, not been
made the subject of microscopical enquiry.
The foliated schists, quartzites, etc., form by themselves a distinct
and well-defined class of metamorphic rocks, characterised by struc-
tural peculiarities differing from all previously treated of.
This appears to be due to their crystalline development having
originated in a solid body, and not from liquefaction ; the minerals
composing them differ greatly in structure from the same minerals
when found in eruptive rocks. Instead of, as in the latter case,
presenting themselves in more or less defined crystals, occurring in
all positions and at all angles to one another, in the foliated rocks
they are developed only in one general direction, not characterised
by well defined bounding planes, but forming a string of drawn-out
and irregularly bounded crystalline aggregations, presenting a
general parallelism to one another, as seen in a section of hornblende
schist from Connemara.
The microscopic examination of these rocks proves their original
sedimentary origin, often showing the contours of the original sand
grains, and, as Sorby has pointed out, the existence of ripple-drift
and wave-structure, peculiar to sedimentary rocks alone. These
rocks appear to have been micaceous and argillaceous sandstones,
the constituents of which have been re-crystallised in siti, owing to
molecular action developed in the solid rock.
The quartz of these schists frequently contains numerous fluid
cavities, indicating that they have been exposed to a pressure under
which the water, always present in more or less quantity in sedi-
mentary rocks, has been entangled and retained during the re-crys-
tallisation of the quartz.
The direction of the lines of foliation or crystalline development is
that of the lines of least resistance in the rock, which commonly
will be the lines of stratification, but in cleaved rocks will doubtless
be those of cleavage. Sorby has alluded to this fact by the names
of “stratification foliation” and ‘cleavage foliation.”
Reports and Proceedings. 519
In conclusion, the author of this short sketch hopes that it may be
the means of attracting attention to the subject, and thereby of
causing a hitherto almost unexplored field of microscopic enquiry to
be more cultivated; and leaves it to his readers to form a correct
estimate of the justness of the sneering assertion that ‘‘ mountains
should not be looked at through microscopes.”
=e Oa es) AN) OC Ee DINGS:
a
Norwicu Grorocicat Socrety.—At the monthly meeting of this
Society, held at the Museum, on the 8rd of September, the President,
the Rey. J. Gunn, in the chair, Mr. Bayfield called the attention of
the members to a paragraph, announcing the finding of a buried
forest when digging the foundations for a dock at Hull. This
would seem to be a continuation of the Norfolk Forest-bed. The Pre-
sident then read the following paper ‘‘ On Recent Formations in the
Valleys of Norfolk.” The mode in which the valleys in Norfolk
have been formed has been satisfactorily ascertained, and the system
may be said to have been worked out. In the valley of the Wen-
- sum, for instance, we perceive how the Post-glacial and Glacial beds,
the Crag and the Chalk, answer to each other on either side, the in-
termediate portions having been scooped out by the agency of water,
aided by ice and snow, in a colder time than the present. The object
of my paper is to point out what has almost escaped observation,
namely, the contrary process, the filling up of the lower part of the
valleys after they have been formed. That they have been scooped
out to a much greater depth than the present level of the marshes,
and turbaries within them, can easily be proved by sinking or boring.
If this were done in the Thorpe marshes, for instance, or anywhere
between Norwich and Yarmouth, we should have to penetrate a con-
siderable depth before we reached the Chalk or the older formations.
At Yarmouth, at Sir H. Lacon’s brewery, the bore was 170 feet deep
before the London Clay was reached. A change, or changes of level’
must therefore be assumed, in order to account for the erosion having
been carried down so far beneath the present level of the water, and,
afterwards, the deposit of mud and soil, and the growth of peat 20
feet thick, up to the present water level.
In the valley of the Ant I have observed, wherever a section has
been presented by the cutting of dykes and ditches, a substratum of
light-coloured, tenacious sandy clay, in which the roots of trees are
abundant. It appears to have been the site of an extensive forest,
which bordered the ancient river. A fine section of this has
been lately shown at Stalham, on the making a boat-dyke from
the river to Mr. Cooke’s malt-house. The alder and birch appeared
to be the prevailing trees. The section showed how this bed was
cut off and truncated on the river side by the turbary, without its
sinking under it; and on the land side how it apparently passed
under the warp and a bed of sand. No trace of shells of any descrip-
tion have been found in this clayey bed; and it has long been a
520 feports and Proceedings.
question with me as to whether it belonged to recent river forma-
tions or to the older beds of the Middle Drift. From observations on
this spot, and also in Irstead, where J have excavated to the depth of
ten feet, and found what appears to be the same deposit beneath
sand and gravel, I incline to the opinion that this bed is of the
older series, down to which the valley was sunk, and which formed
the land on which the forest grew.
The trees of this forest appear to have been thrown down by
winds or floods, and to have become imbedded in the turbary, which
is, in many places, twenty feet deep, and which extensively covers
this bed. The oak resembles the Irish bog oak ; it will take a good
polish, and is very durable, even when exposed to the air.
With respect to fossil remains, I have not succeeded in finding
any, except some bones of a large bird (taken from the sand im-
mediately above the Forest-bed, and which might be part of the
valley deposits), and also the jaw of a small carnivorous animal.
On this clayey bed rests a turf deposit, of varying depth—
shallow at the sides of the valley, and generally deeper in the centre.
In this human bones are not unfrequently found (about eighteen fine
specimens of old British skulls were taken from a staithe-dyke,
opposite to the one I have already mentioned), and bones of the deer,
horse, and ox are not uncommon. Hazel-nuts are frequent, and
their immature growth seems to mark the period of the year at
which they were imbedded.
With respect to the age of these deposits, the clayey bed—if it
belongs to the Middle Drift—would precede any deposit in which
relics of man have as yet come to light. With respect to the
peat formation, it may be regarded as one of the most recent prior to
the historic period. The first vestiges of man, as yet fully ascer-
tained, appear in the oldest of the valley gravels and lacustrine beds.
From this peat, which in part filled up the valley after it was
hollowed out, querns and celts have been taken, and a bronze spear-
head (placed in the Norwich Museum by Mr. Cooke) is supposed
to have belonged to it.
Besides the growth of peat, that of estuarine and fluviatile mud
may be added, which is from year to year accumulating wherever
the water overflows the land and leaves its sediment. ‘This, in our
Norfolk broads or lakes, is frequently found to be ten or twenty feet
in depth; but, I believe, not an instance can be shown in which
shells are absent from it; and this appears to me to mark the
character of the clayey bed as not being a member of the river
valley formation, but of the Middle Drift age. I am not, however,
confident on this point, for want of sufficient data.
A communication was next read from Mr. Searles V. Wood, junr.,
having reference to “the deposits of the old estuary of the Yare,”
described by Mr. Prestwich as covering the London Clay at Yar-
mouth, and which were penetrated in a well-boring at Lacon’s
Brewery,—the report of which is deferred.
Correspondence. del
CORRESPONDENCE.
————— .———
GREAT TRAP-DYKES AND REMAINS OF AN ANCIENT FOREST
IN SKYE.
To the Editor of the Gro~ocicaL MAGAZINE.
Sir,—Having just returned from a trip in Skye, there are two
points I wish to draw the attention of your readers to. The ancient
forest of the Highlands and the great trap-dykes of the district.
You favoured me last year with the insertion in your Macazinu
of my views respecting the ancient forest. I subsequently found
them, in great measure, confirmed by Mr. Geikie. I sought in vain
in the peat-bogs of Skye, in the Sligachan district, amongst the
Cuchullin Hills, for remains of this forest ; but found them beauti-
fully exhibited at Kyleaton.' It is everywhere hidden under beds of
peat, until the peat-diggers expose them; then the stools are seen
standing up two to three feet high, so hardened by the action of bog-
water, that vain is the attempt to cut them, and, as a rule, they are
left behind, rooted in the gravel in which they grew—the gravel-
bed of Scotland—here covered up with that interloper peat, in which
no trees can live. J am therefore confirmed in the view before
expressed, that the destruction of the ancient forest is owing to
climatal changes of great antiquity. I was desirous of ascertaining
the species of fir to which these stools belong. At last the quick
eye of my brother, a botanist, saw the cones spread around two of
the stools; the peat had preserved them as it preserves the wood,
and the roots of bog-plants; they expanded, in drying, like recent
cones of Scotch fir. I could discover no difference between them
and recent Scotch fir, and therefore consider the trees were of the
indigenous conifer of Scotland, now existing. There seems no
reason why they should not be preserved in localities where peat
did not grow, or where they were not exposed to the violence of
the western winds.
Skye, like all other Islands of the western sea of Scotland, as
shown by Sir R. Murchison’s sketch-map, is chiefly composed of
eruptive rocks, which consist of two kinds, the more considerable
and ancient, due to that great development which raised the
Cuchullins greater hills 3,200 feet at Scuir-na-Gillean, and the much
later, or trap-dykes.. The first of unknown primeval age, to which
we may assume we owe the earliest elevation of the land above
the sea; which lifted mountain ranges as well as the younger
strata, modified by denudation of the ocean, and no doubt since
moulded by atmospheric agencies. These major mountains of Skye
are composed of what is called Hypersthene, and are distinguishable
from others by their hardness, and by their aiguille points, which
nothing alters. They throw down no débris from age to age, but
shoot off the rains of the Atlantic at once, as from the roof of a
house. The flanks of Scuir-na-Gillean present the appearance of
1 Kyle-Rhea, or Kyle Akin ?—Eprr.
022 Correspondence.
lava-currents, great sheets of which may be seen descending to the
sea-shore, where they are sometimes thrown up in rugged masses,
as though acted on by the sea-water when in a state of fusion, as
may now be seen in Sicily.
Next to these most ancient rocks come the lower hills, whose origin
we assign to a somewhat later period, when the volcanic action was
dying out: these are composed of materials readily acted on by the
atmosphere, and are thus shaven into cones. I must now refer to the
trap dykes. Every geologist who has studied the Western Highlands
well knows the great area which has been subjected to volcanic action
at a comparatively late period. In the low grounds, in the beds of
rivers, and on the sea shore, we find trap-dykes, from one inch to
several feet in width, passing through the more ancient beds, into
which various qualities of trap have been injected. This appears to
me to have been the subsiding action of the great elevatory force,
and it is interesting to find it extending in Scotland up to the Ter-
tiary period, for Skye offers at Broadford most interesting examples
of trap-dykes traversing the Lias limestone.
I will only add, that subsequently to the periods referred to, came
that universal surface action by which all Scotland and the North of
England have been covered with gravel beds—a subject deserving
deep and persistent enquiry. In these beds the primeval forest
grew, which, in its turn, has been buried beneath peat or soil, the
surface of which is now adorned with the flora of our modern time.
Yours,
Taos. C. Brown.
FurtHer Barton, CIRENCESTER,
1th September, 1867.
THE ORIGIN OF GRANITE.
To the Editor of the Gzotocican MaGazine.
Srr,—I am glad to see “the origin of granite” is likely to crop
up as a result of Dr. Sterry Hunt’s Lecture “ On the Chemistry of
the Primeval Earth,” which has been so ably commented on in the
last number of the Gronogican Macazine by Mr. David Forbes.
There has been so much “ Denudation” of late, both marine and
atmospheric, that we need not be surprised if a deep-seated rock,
like granite, is laid bare, and at last appears on the surface in the
field of geological discussion.
At the recent meeting of the British Association in Dundee, Pro-
fessor Ansted communicated a paper ‘On the Conversion of Strati-
fied Rock into Granite in the North of Corsica.” I took part in the
discussion which ensued; but as my remarks, together with those of
Sir Charles Lyell and Mr. Geikie, were reported thus—‘‘Some dis-
cussion followed the reading of the paper,” while those of Professors
Phillips and Ramsay were merely noticed, I venture to ask you to
have the kindness to permit me to re-state in the pages of the
Guotocican Magazine, as briefly as possible, the substance of what
I said on that occasion.
Correspondence. 523
Professor Ansted entered into some wide generalizations favour-
ing the metamorphic origin of granite. I happen to reside in a dis-
trict where the intrusive character of that rock is particularly well
shewn, and I could hardly allow his views to pass unquestioned.
There is in this country the largest exposure, and perhaps the
greatest variety, of granite in the British Islands, and I trust that a
short account of my observations, which have been made with some
care, may not be without interest.
There are four large tracts of granite in Ireland—(1) The Leinster
district, ranging from Dublin, through Wicklow, into Wexford ;
(2) the Mourne Mountain district, in the Co. Down; (8) the
Donegal district; and (4) the Connaught district. Granite also
occurs in smaller masses in other parts of this country.
The Leinster granite (1) is unquestionably intrusive ; it pene-
trates into Lower Silurian Slates, which are everywhere altered into
mica-schist as they approach it, and are pierced by numerous granitic
dykes. The Mourne granite (2) has a similar character, though the
metamorphism of the surrounding rocks is not so extensive as in
Leinster: it is supposed to be a newer rock than that of Leinster,
being believed to be post-Carboniferous.|_ The Donegal (8) and
Connaught (4) granites are of a totally different character. They
are essentially of a metamorphic type, being bedded and, in Donegal,
interstratified with limestone ;? they do not intrude into, but form
part of the great mass of gneiss, schist, quartz-rock, and limestone
among which they occur.
If two geologists were to set to work to investigate the origin of
granite, and if one were to locate himself in Leinster and the other
in Donegal, the Leinster geologist could bring forward the most
convincing proofs of the intrusive character of granite, while the
Donegal observer could produce equally conclusive arguments in
favour of its metamorphic nature.
I am ata loss to understand how any one could explain the Leinster
granite by the metamorphic theory, yet the Donegal rock appears to
be but an instance of an advanced or perfected stage of that meta-
morphic action which is less fully developed in the varieties of
gneiss. Any geologist who has examined gneissose districts may
1 Jukes, “‘Student’s Manual of Geology,” pp. 93 and 313. I think, however,
further proof is required as to its being of the same age as the rock which alters the
Carboniferous Limestone near Carlingford: it rather differs in appearance and mineral
composition from the Leinster granite, containing other micas, and notably by the
occurrence in some places of albite (Haughton, Quart. Journ. Geol. Soc. vols. xii, and
xiv.), though I believe that this feldspar is not so important a constituent as has been
supposed.
2 Brit. Assoc. Report, 1863; Scott, Journ. Geol. Soc. Dublin, vols. ix. and x. See
oe Haughton, “On Granites of Donegal,” Quart. Journ. Geol. Soc., vols. xviii.
and xx.
3 There can be little doubt that some intrusive granites do occur in Donegal and
perhaps largely in Connaught: we require further information on this point; a red
patch on a map, lettered G for granite, does not teach us much.
[‘‘ Stratified eruptive rocks,’ See Forbes, ‘‘The Microscope in Geology,” in this
number, p. 615.—Kn1r. ]
524 Correspondence.
remember to have seen true gneiss which, in a hand specimen, it
would be impossible to distinguish from granite.
Now I ask—Are we to suppose that, notwithstanding the vast
difference between their modes of occurrence in the field, the
granites of Leinster, and the granitoid rocks of Donegal must have
had a like origin, merely because they have a somewhat similar
mineral composition, both containing quartz, feldspar, and mica ?
But have these rocks an identical mineral composition? So far as
my experience goes, most assuredly not. They vary in appearance,
texture, and mode of aggregation of the component minerals; the
quartz has a different look, difficult to describe, but once seen and
observed, not easily to be forgotten ; but above all, they differ widely
in their feldspathic constituents, for while the intrusive granites are
orthoclasic or, as in Down, sometimes albitie (and, let it be remem-
bered, albite is as highly silicated as orthoclase), and the uncrystal-
lized feldspathic paste is always highly silicated, the granitoid rocks
on the other hand contain, notwithstanding the presence of free
quartz, a large proportion of basic feldspars, of which oligoclase is
the most recognizable, and the feldspathic paste is basic also, ap-
proaching oligoclase or anorthosite! in composition.
During a recent visit to Scotland I had these views fully con-
firmed by the facts which I observed there. ‘The intrusive granites
of Arran are extremely like those of the Mourne district, while
many of the Highland rocks appear to pertain to the metamorphic
type. As my visit was very hurried, I cannot now commit myself
to details; neither shall I say anything of the intrusive and meta-
morphic characters of the hornblendic series of rocks, such as green-
stones, syenites, and hornblendic schists.
The views now put forward are only suggestive: my field of
observation has been too limited to warrant my entering into gene-
ralizations, but I trust they will tend to elicit further opinion on this
important subject. So long as our knowledge is added to, it matters
little whether these views are corroborated or refuted by such in-
vestigators as Forbes, Haughton, Hunt, and Sorby, men who combine
the highest chemico-mineralogical attainments with great knowledge
of physical geology, accomplishments which unfortunately do not
often co-exist in the same individual.
In conclusion, I think the last passages of Mr. Forbes’s paper
(Guot. Mac. Vol. IV. pp. 442—444), deserve the serious attention
of every one who may be inclined to go in for the metamorphic origin
of all granite.
I am, Sir, your obedient servant,
W. H. Sracpootr WESTROPP.
Buackrocx, Dusiin, October 5th, 1867.
Since writing the above, I have looked into Haughton’s Manual of
Geology, and find that I have been anticipated in suggesting a two-
fold origin for granite. In that work (p. 45) the terms hydro-
metamorphic and pyro-metamorphic are proposed. I fear that the
1 Geol. Report, Canada, 1854; and Bigsby, Grou. Mae. Vol. I. p. 157.
Correspondence D205
latter word smacks of the old “ dry fusion” theory, though, as every
one knows, Professor Haughton’s speculations are anything but dry.
FORBES.—CHEMISTRY OF THE PRIMEVAL EARTH.
To the Editor of the GrotogicaLn Macazine.
Str,—Under this heading, page 434 of your October number, are
these words, ‘‘ Hutton, the propounder of the plutonic theory of the
world’s origin, which assumed the world to have been at one time a
sphere of molten matter solidified by refrigeration.”
I think that there must be some great mistake here. I do not
think that Hutton would attempt to lift the veil of Isis, or to account
for the “world’s origin” at all, or for the “ origin” of anything what-
ever, animate or inanimate ; not even for the “ origin” of the smallest
particle of matter. His word is “no sign of a beginning, no prospect
of an end.”
I have, indeed, never had access to Hutton’s work; but I have by
me Playfair’s illustrations of it, Edinburgh, 1802, and he totally
repudiates the idea of the original fusion of the globe, either igneous
or aqueous, partial or entire. The igneous theory he imputes (while
he controverts it) to Buffon. Page 136, section 132, and note xxv.
Playfair accounts for the orange shape of the globe by a most beauti-
ful theory of his own, entirely dependent on Hutton’s doctrines, and
therefore entirely dependent on rain and rivers.
The principles which poise the wniverse are as simple as they are
sublime ; and it is not only, as Professor Jukes remarks in your last
number (p. 144), that “the form of the ground” depends on rain
and rivers, but, as Playfair says, the statical figure of the globe
itself,—the spheroid of equilibrium depends on rain and rivers, on
causes now in operation. Those who have not access to Playfair’s
work may see his beautiful theory as to this clumsily explained by
me in the eleventh chapter of ‘‘ Rain and Rivers.”
I have the honour to be, Sir, your most obedient and most obliged
servant,
GrorGE GREENWooD, Colonel.
Brookwoop Park, ALRESFORD,
Ath October, 1867.
THE CHEMISTRY OF THE PRIMEVAL EARTH.
To the Editor of the GrotogicaAL MacGazine.
Srr,—I hope the space at your disposal will admit of the inser-
tion of a few remarks in reply to Dr. Sterry Hunt’s letter, on page
478, and in defence of my report of his lecture “ On the Chemistry
of the Primeval Harth:” (Guon. MaG., p. 357).
Dr. Sterry Hunt’s communication must not be allowed to mislead
you or your readers into the belief that I am responsible for the
twenty errata which have been tabulated in the two published lists,
(pages 432 and 478), for, in fact, only fowr of these mistakes have
originated with me. Of these four I am perfectly willing to bear
the blame. The first occurs in the passage (page 361) relating
526 Correspondence.
to the fusing point of certain bodies being augmented by pressure.
In taking down this sentence from the lecturer’s lips, I was in some
doubt as to the words used, and I recorded those which I understood
him to utter. You, however, have set the passage right by means of
a very simple alteration. My second error was the substitution of
the word decomposed for recomposed. This obviously arose from
similarity of sounds. On page 367, the letter “p” is inserted in
Professor Thomson’s name, but I find that Dr. Sterry Hunt has
himself committed the same mistake in the report of his lecture in
the Chemical News. My fourth error is the substitution of the word
ault for coal. This occurred in transcribing my notes,
Of the other errata, three are what are familiarly termed “ printers’
blunders.” They consist of the substitution of the words seven for
several, orchid for orchard, and mutation for nutation. These might
have been avoided if I had seen a proof before the Magazine went
to press.
The remaining thirteen corrections are, in reality, emendations of
the lecturer’s own words, and departures from the actual language of
the lecture. These errors are, for the most part, only such as are
common to unwritten discourses; but they cannot, as Dr. Sterry
Hunt would imply, be with any fairness classed under his descrip-
tion of “mistakes into which the reporter has fallen; and I must
beg leave to protest against being held responsible for the lecturer’s
own inaccuracies of expression. |
If Dr. Hunt prefers the version of his lecture given in the Chemical
News, it cannot be because it approaches more nearly to what he
actually said than the version which you have published. If the
Chemical News report was founded upon shorthand notes at all, the
author has performed the work of revision so vigorously that the
original transcript has disappeared.
I am, Sir, obediently yours,
Tur SHORTHAND WRITER.
Lonpon, October 17th, 1867.
SHELLS ON THE GREAT ORMESHEAD.
To the Editor of the-GrotocicaL Magazine.
Dear Srr,—Owing to my absence from Cambridge, I have only
lately seen Mr. Maw’s letter, in the August number of the Maga-
zine. 'The shells which I found at Gwydfyd were by no means in
such numbers, or in such a condition, as to suggest to me the idea
that I was on a kitchen-midden. If that be the case, they are very
different to those in the kitchen-middens on the N.W. side, and,
though I cannot speak positively, I am disposed still to adhere to
my original opinion. Yours very truly,
T. G. Bonney.
Sr. Jonn’s CoLLEGE, CAMBRIDGE,
Correspondence. 527
NOTE ON THE CONTENTS OF THE POCKETS IN THE CARBON-
IFEROUS LIMESTONE AT LLANDUDNO.
To the Editor of the GrotocicaL MAGAZINE.
Srr,—An examination of the contents of the pockets in the Car-
boniferous Limestone near Llandudno has brought to light some few
fossils that may tend towards solving the problem of the origin of
these curious accumulations. A reference to Mr. Maw’s paper on
the same subject in Vol. II., No. 4, of the Grou. MaG., will give a
clear description of the general character and position of the de-
posits. Those which I examined are three in number: one near the
Little Orme, at Nant y Gamer, and two on the Great Orme, close to '
Wyddfyd Farm. At the former locality there are two large pockets
known; one of these, the upper one, is now nearly emptied and is
abandoned, the other is an open pit of considerable size, reached by
an adit driven in the hill-side through the Boulder-clay drift and the
limestone rock beneath. This pit contains, immediately beneath the
drift and sharply contrasting with it, some ten yards of beautifully
white sand, mixed in places with equally white clay ; the clay is also
here and there variegated with red; it forms the floor of one side of
the pit, and its thickness has not been ascertained. In the sand there
is in one place a thickish kind of vein, consisting for the greater part
of oxide of manganese ; it is amorphous and pulverulent ; this is said
to extend beneath the floor to a depth not yet known. On looking
over the clays and sands in this pocket I found traces of fossils,
chiefly in the former; portions of Encrinites were tolerably plenti-
ful, apparently derived from the Carboniferous Limestone, the other
fossils were not so distinct, but may be parts of Producti; they were
very fragile. The white clay was in places filled with pieces of
white chert, and some of the fossils may have come from this, as I
have no doubt this chert and that also at the base of the Boulder
clay on the shore, is derived from the Limestone, although I could
find none in siti in the neighbourhood. Some of the Limestone
forming the walls of the now abandoned pocket is very curiously
banded with white and red; it is rather shaly or fissile, and is also
here and there slightly silicious ; it contains many crinoidal and other
fossil remains. How far back towards the old pocket the lower one
may extend is not yet known; it is not improbable that the two
may be connected.
On examining the deposits of fire-clay with sand and chert at
Wyddfyd Farm, I found in the sand, or rather sandy clay,. which
overlies the thick clay, very numerous pieces of chert, some of large
size; these undoubtedly belong to the Carboniferous Limestone, for
they are crammed with casts of Hnerinites, and resemble closely
what in Derbyshire are called ‘‘Screw-stones.” ‘The chert is whitish
or drab, but is often very much decomposed and yellowish, and
crumbles very readily into a kind of sand. Is it impossible that the
sands in the pockets may thus have had their origin? The sand a
little beyond Wyddfyd Farm contains very many joints of Encrin-
ites, besides traces of other fossils. One piece of sand, I found, has
528 Miscellaneous. .
a tolerably distinct impression of a fossil shell in it, which may
perhaps be sufficiently distinct to enable its name to be ascertained.
Fragments of Carboniferous Limestone were not uncommon in this
sand-pit. From its position it is not easy to say for certain whether
it overlies or underlies the clays at Wyddfyd Farm. It has been
dug into to a depth of some eight or nine feet. I have sent speci-
mens of all the above-mentioned deposits, in the hope they may
throw some little light upon their origin.
J. M. Metno.
Sr. THomas’ ParsonaGeE,
BrRampron, CHESTERFIELD.
MIiSCHiMAN HOUS.
————
Discovery oF A Muw Minera (‘“ Crooxesite”’).— Whilst ex-
amining the seleniferous minerals from the Skrikerum mine, in
Sweden, M. Nordenskiold has discovered that thallium exists in
small quantities in eucairite ( (Cu Ag) Se) and berzelianite (Cu Se).
Continuing his researches among these selenides, in Mosander’s col-
lection, he has found a mineral which contains from seventeen to
nineteen per cent. of this metal. It occurs in small opaque masses,
having a metallic lustre and lead-grey colour, mixed with the grains
of eucairite and berzelianite. From these it is easily separated, and
on analysis gives the formula (Cu, Tl, Ag) Se. Density—6-9. No
crystalline faces yet observed. Before the blowpipe it fuses easily
into a shining greenish-black enamel, and the flame is coloured
intensely green. Insoluble in hydrochloric acid, but nitric acid
dissolves it completely. M. Nordenskiold has named this new
mineral “ Crookesite,” after the well-known discoverer of thallium.
But few specimens have been yet found of Crookesite, but M. Nor-
denskiold hopes to obtain more by carefully searching the Skrikerum
mine, which has been for some time abandoned.—T.D.
A Kine-Cras in tHe Upper Siturtan.—Among the fossils ex-
hibited by Mr. Robert Slimon at the meeting of the British Associ-
ation in Dundee, and collected by him at Lesmahagow, in Lanark-
shire, was a minute form of Crustacean, nearly allied to Belinurus, in
which all the body segments appeared to be free and unanchylosed.
In calling attention to this beautiful little fossil, Mr. Woodward
pointed out the great interest attaching to its discovery, as being the
oldest representative of the Xiphosura, or King-Crabs, known, carry-
ing this division back in time from the Coal-Measures to the Upper
Silurian.
Erratum in Mr. Forbes’ Article in the October Number.
On p. 443, in footnote, in line 21 from foot of page, for “‘ before,” read after.
Geol. Mag 1867
A T Hollick del
New Genera of Crustacea from the London & Plastic
Vol IV. PUXAT.
Clays.
A
THE
GEOLOGICAL MAGAZINE.
No. XLII—DECEMBER, 1867.
ORIGINAL ARTICLIES.
————
I.—On a New Genus or SHorRE-crAB, Gowrocypopa Epwarbst.
FROM THE Lower Eocrenr or Hampsurre.!
By Henry Woopwarp, F.G.S., F.Z.S., ete.
(PLATE XXI. Fig. 1.)
NE of the characteristic features of the warmer and intertropical
regions of the globe, is the presence in abundance of those
highest forms of Crustacea, the Shore- and Land-crabs.
Along our own coast, the common shore-crab, Carcinus meenas,
prevails; on the coast of Spain the genus Grapsus is equally
abundant; whilst in the Eastern seas the shores are tenanted by
Gelasimus, Macrophthalmus, and Ocypoda.
Among the Decapodous Crustacea which have rewarded the
labours of the palzontologist, and furnished materials for Mono-
graphs by Professors Bell, Reuss, A. Milne-Hdwards, and others, no
fossil remains of the Quadrangular Crabs have hitherto been recorded
as occurring either in this country or on the Continent.
So long ago, however, as 1822, M. Desmarest? had figured and
described one species of Grapsus, five species of Gonoplax,? one
species of Gelasimus, and one of Gecarcinus, which were probably
all from India and China (although the history of some was un-
known) ; for fossil crabs of these species are still sold in the Bazaars
of the Hast as a medicine.* It is highly interesting, therefore, to
record the occurrence, in the fossil state, of a true shore-crab, near
to Ocypoda, from the Red Marl of the Plastic-clay, of High Cliff,
Hampshire.
These Plastic or mottled clays and sands, which lie immediately
below the London Clay, contain many subdivisions representing re-
peated changes in the conditions under which they were deposited,
1 This new species was noticed by the author at the Dundee Meeting of the British
Association.
2 Brongniart and Desmarest, Histoire Naturelle des Crustaces Fossiles. 1822.
3 Prof. Dr. A. Reuss. Zur Kenntniss fossiler Krabben in Denkschriften der K,
Akad, d. Wissensch. Mathem. natur w. cl. xvii. Bd. Vienna, 1859. Taf. xx. and
xxili., p. $2 has figured and described four species of Macrophthalmus from the East
Indies and Molucca.
4 See Notes on Chinese Materia Medica, by Daniel Hanbury, F.L.S. (Reprinted
from the Pharmaceutical Journal, February, 1862, and other numbers), p. 40.
“ Shih-heae,” Fossil Crabs of the Post-Tertiary period, obtained from the Island of
Hainan and on the opposite shores of Kwang-si.
VoL, IV.— NO, XLII, 34
530 H. Woodward—On Goniocypoda Edwardsi,
sometimes—as their contained fossils prove—marine conditions pre-
vailed, at another freshwater, at a third estuarine. But whatever
these conditions were, the contained organic remains indicate a
warmer climate than is enjoyed by us in the same latitude at the
present day.
The Crab which forms the subject of these remarks was collected
by Mr. B. Porter, and now forms a part of the geological collection
in the British Musuem. It is preserved in a small slab of Red
Marl or Clay, having the dorsal aspect exposed to view. ‘The
counterpart or intaglio is also preserved, and affords some additional
details.
Diagnosis of the genus Goniocypoda.—Carapace quadrangular, nearly
one-third broader than long, tumid, borders rounded, surface granu-
lated sparingly, regions of carapace but little distinct from each
other; lateral border of carapace entire, deep, forming nearly a right
angle with dorsal surface, posterior border straight, anterior angles
curving inwards and terminating in the external orbital angle:
rostrum small, square: front border of carapace nearly straight
and occupied by the orbital fossee; eye-stalks long: fore-arms short,
feeble; thigh of walking-legs broad and flattened, and slightly ser-
rated at distal end: feet formed for running. (The Abdomen and
antennee, if present, are concealed in the matrix).
I have carefully compared this Hocene Crustacean with Grapsus,
Gonoplax, Macrophthalmus, Gelasimus, and Ocypoda, It differs from
Grapsus in the absence of dentations on the latero-anterior border,
in the greater lateral breadth of the carapace behind, and in the
greater length of the eye-stalks. It approaches Grapsus only in the
form of the limbs, and the smallness of the hands. Goniocypoda is
distinguished from Gonoplax by the more rectangular form of the
lateral and posterior borders, and by its short, somewhat thick hands
and chelee.
From Gelasimus and Gonoplax it also differs, in having the latero-
anterior angles of the carapace curved in towards the external orbital
angle. Compared with Macrophthalmus the relative proportions of
the length and breadth of the carapace are much the same; but
Goniocypoda differs from Macrophthalmus in the same point as it does
from Gonoplax and Grapsus; namely, in the absence, in the fossil,
of dentations along the latero-anterior border.
The form of the rostrum closely corresponds with Macrophthalmus
and Ocypoda ; and in both genera the orbital fossee occupy the whole
breadth of the front of the carapace; they are much curved in the
two recent genera, but nearly straight in the fossil. The cara-
pace in Ocypoda is almost equilateral, in Goniocypoda it is one-third
broader than long.
Goniocypoda Edwardsi (Pl. XXI. Fig. 1.)—This neat little crab, is
smaller than the Macrophthaimus dilatatus of De Haan, the carapace
being eight lines in greatest breadth, and five lines only in length:
the rostrum is only one line in width, and projects the same distance
in front, being bent downwards as in Ocypoda: the eye-peduncles
are two lines in length, and are but slightly curved: the external
A new Eocene Crustacean. pol
orbital angle is marked by a strong incurving spine, which also
forms the latero-anterior angle of the carapace.
As is the case with all land- and shore-dwelling crabs the carapace
is much swollen, especially in the branchial regions: the cardiac
region is marked by four faint tubercles, the gastric by two lateral
depressions marking the line of separation between the gastric and
branchial regions; with these exceptions and a few scattered granu-
lations on the surface, the carapace is destitute of any well-marked
surface-features or divisions into regions. The fore-limbs are nearly
equal in size, the arm is almost entirely concealed beneath the
carapace, and is very short; the fore-arm is tumid, and is not
ornamented with spines along its border: the hand is short and
smooth ; the fixed ramus and moveable finger being furnished with
three or four small teeth along their edges. Three of the true
walking legs are preserved on the left and two on the right side;
outlines of the absent limbs are given in the figure. As before
stated, in form, these limbs closely resemble those of the Grapside.
I have failed in my attempt to work out the underside by reason
of the exceeding fragile nature of the fossil; but I have no doubt the
specimen here described and figured was a female; indeed there is
evidence of the first wide abdominal segment behind the posterior
border of the carapace. The smallness of the hands would also con-
firm this view, as in most, if not in all the quadrangular crabs, the
male has one or both hands large and well-developed, whilst those of
the adult female remain small and feeble.
From the nature of the fossil, I am necessarily unable to offer
more than a very incomplete description of Goniocypoda, but I think
the occurrence of such a rare Crustacean novelty is a sufficient
excuse for placing it on record, in the hope that more perfect
remains may thus be brought to light.
I have designated it Goniocypoda Edwardsi, after MM. Drs. Henry
and Alphonse Milne-Hdwards, who have by their labours done so
much to advance the study of recent and fossil Crustacea in Europe,
and for whom I entertain personally so high an esteem.
Il.— On Nacrozivs Bownreayxu, A NEw Gunus oF CanceRIDEZ
FROM THE Lonpon Cuay.!
By Professor AtpHonsE Mitnz-Epwarps, D.Sc., M.D., etc., ete.
(PLATE XXI., Fras. 2 and 3).
N the genus Wecrozius.—This new genus is very near to Ozeus, and
is still more near to a small genus, established a few years since
by M. Stimpson, named Spherozius. Like this last-named form, the
carapace of WVecrozius is remarkable for its globular form, its width
scarcely surpassing its length. The curve of the buckler is slight in
a transverse direction, but is great from back to front, the anterior
1 Translated from the “ Histoire des Crustacés Podophthalmaires Fossiles,’”’ par
Alphonse Milne-Edwards: (Reprinted from the Annales des sciences Naturelle.
Tom. xviii., 4te series, pp. 297). Paris, 18665.
532 A. Milne-Edwards—On Necrozius Bowerbankii,
border being much curved down. The latero-anterior borders are
continuous, almost without interruption, with the latero-posterior,
which latter are swollen. The frontal border (rostrum) projects a
little, and is slightly depressed in the centre. The basal joint of
the internal antennz is large, and it is articulated obliquely beneath
the front (rostrum). The basal joint of the external antenne is
short, not reaching to the front as in the Pseudozius of Dana, and in
Spherozius of Stimpson ; the articulation is free and is not lodged in
the internal obital cavity. With Ozcws on the contrary, this basal
joint is fully attached to the front.
I have unfortunately been unable to examine the endostome, so
that I could not determine the characters shown by the absence or
presence of the tubercles (crétes) which, in Ozius, are confined to the
neighbourhood of the expiratory canal of the branchial chamber.
The labial border was also concealed by the matrix, as are certain
parts of the specimen between the hands, so that I have been
unable to see if the border was complete, or sloped off as in Ozvus.
The anterior feet are very strong, and unequal in size, the smallest
being only half the size of the largest, their proportions and appear-
ance enabling one at once to distinguish the crustaceans of this
section.
The walking feet are cylindrical; they are not tuberculated, and
in this latter respect they resemble those of Ozcus, Spherozius, and
Pseudozius. The abdomen in the male, as in the three preceding
genera, is composed of seven segments, all of which are free.
This genus, as we have already said, is very near to Spherozius.
The basal joint of the external antennz in Ozius reaches the front ;
in Pseudozius, Spherozius, Necrozius, it is distant from it.’ Pseudozius
has a rather elongated carapace, while in Spherozius the carapace is
more globular. This last genus differs from WVecrozius in having a
more swollen carapace, and the front is continuous, without inter-
ruption, by an insensible curve with the superior orbital border ; in
Vecrozius, on the contrary, the internal orbital angles are well marked.
Necrozius Bowerbankii, Alph. Milne-Edwards.—This pretty species
is from the London Clay of the Isle of Sheppey, which has furnished
so many interesting crustaceans.1 It formed a part of the rich
collection of Dr. J. S. Bowerbank, who, with his accustomed
scientific liberality, obligingly placed it at my disposal.?
This crab appears to be extremely rare, for Professor Bell does
not notice it among the Crustacea of the London Clay, and I have
never seen but this single specimen, perfectly preserved it is true,
although I have examined the collections of the British Museum, the
Museum of Practical Geology, and many others almost as rich.
Description of the Species.— The carapace is closely covered
on all the salient parts with minute rounded granulations. The
1 [The specimen here referred to, and which is figured in our plate (Plate XXI.
figs. 2 and 3), was obtained some years since by Dr. J. S. Bowerbank, F.R.S., from
the London Clay, Holloway, when the Great Northern Railway was in course of
construction. ‘Two less perfect specimens have, however, since been obtained from
Sheppey.—H.W.]
2 [The type-specimen here figured is now in the British Museum.—H., W.]
_A new London Clay Crustacean. 533
furrows which separate the various parts are smooth. These latter,
without being very salient, are plainly indicated. On the gastric
region, the epigastric lobes are not distinct from the protogastric ;
the mesogastric stretches from a point between these to the middle
slope of the front. The metagastric lobe is distinct from the
urogastric. The branchio-cardiac furrow is strongly marked. The
cardiac region is rounded and gently sloped off in the rear. The
hepatic regions are separated from the branchial by a shallow de-
pression; the latter are rather swollen, and show an ill-defined
lobule near the urogastric lobe.
The latero-anterior borders of the carapace are thick; they exhibit
in the midst of the granulations which cover them, three or four
little tubercles scarcely larger than the granulations themselves.
The external orbital angle does not project in the form of a tooth.
The orbits are very small and point directly forward. The super-
ciliary arch is well marked, and has no fissure. The front (rostrum)
juts forward straight and is furrowed down the centre. The pterygo-
stomian regions are finely granulated.
The anterior feet are unequal, the fore-arm shows a small blunt
projection within, on the outer side it is smooth: the large hand is
smooth both above and below, and is not tuberculated; the fingers
are short and thick, the thumb is ornamented near its base with
a strong tooth, the fore-finger has two rounded teeth. The small
hand is finely granulated or rather roughened, the fingers are
slender and longer in proportion than those of the large hand.
The walking feet are smooth, having neither granulations nor
tubercles. The various parts of the sternal plastron are granulous.
All the rings of the abdomen are free, as we have already said, in
describing the characters of the genus.
EXPLANATION OF PLATE XXI. Fics. 2 & 3.
Fig. 2. Dorsal aspect of Neerozius Bowerbankii, A. Milne-Edwards ; twice nat.
size.
», 3. Front view of same, showing the Orbital and Antennary fosse and the
chele ; twice nat. size.
Til.—Tue Kitouen Mippens at Luanpupno.
By the Rev. J. M. Meno, M.A., F.G.S., etc.
WEEK or two spent last month at Llandudno has given me
the opportunity of examining the deposits on the Great
Orme’s Head, described by the Rev. T. G. Bonney in the August
number of the GronocicaL Macazrne, and supposed by him to be
the remains of a Kitchen Midden. The present communication is
intended merely as a supplementary note to his paper. It appears
that the beds, containing recent shells and bones, had been pre-
viously observed, and their true character ascertained, since the Rev.
W. S. Symonds remarks, in some notes on the Geology of the
district, ‘The beds of mussels and other shells on the Great Orme,
which, at one time I imagined to have been elevated in raised
5384 Mello—Kitchen Middens in Wales.
beaches, Mr. Darbishire believes to be derived from old shell-heaps,
the accumulations of former inhabitants.”
The beds in question appear in the face of the low cliff, which
terminates a somewhat steep talus, covering the base of the Carbo-
niferous Limestone escarpment of the Great Orme, close to Pen
Morfa. Part of the talus has been carried away by the sea, and the
present cliff is only a foot or two above high-water-mark.
Fie. 1.—Currr ar Pen Morra, Great Orme’s Heap.
Suan SR Peres
San
3. Se) TERS r
Bestel
TES EL EE
LEE
770
Te rh le hay
Ves
BAO rege 4,
4 s
GHEEE Lear", Pacage & 9
f
AE 7 t
1. Surface soil with angular blocks of limestone, Helices and other shells, etc., 13 to 23 feet.
9. Calcareous dust and tufa, about 10 inches.
8. Sandy soil and limestone fragments, with shells of Mytilus edulis, Patella vulgata, Littorina
littorea, ete., bones, teeth, charcoal, etc., 1 foot.
. Sand with pebbles and angular limestone fragments, 6 inches.
. Reddish clay, 8 or 9 inches.
. sand il
>, darker \ 3 to 4 feet.
. Talus of all the above. }
. Pocket of shells of Mytilus edulis.
a. Line of section. 6. At the spots indicated below, in bed No. 3, two jaws of a small sheep
were found. ec. Wall at Pen Morfa.
The general appearance of the face of the cliff is given in the accom-
panying sketch (Fig. 1), which, though not drawn to scale, represents
with sufficient accuracy the different beds as they occur. These are
more minutely shown in the section given in Fig. 2; it is taken about
20 yards from the beginning of the Midden, or from the first rise of
the cliff at Pen Morfa. The beds occur as follows :—
1. Surface soil with angular fragments of limestone, ete., with some Helices, about 1 ft.
. Bed of Patella vulgata, with a few bones, 4 in.
. Calcareous dust, like decomposed tufa, about 9 in.
. Dark-coloured tufa, $ in. to 1 in.
2
3
4
5. Dark Carbonaceous layer, 1 in.
6. Soil, with Patella vulgata, Littorina littorea, Mytilus edulis, etc. and bones, 3 in,
7
8
9
OND Oe
. Sooty layer, with fragments of charcoal and burnt bone and shells, 3—4 in.
. Bed of burnt clay, with calcined pebbles, 3 in.
. Whitish sand, 1 in.
10. Dark-coloured loam, with fragments of charcoal and burnt shells, 2 in.
11. Thin layer of Carbonaceous matter, with burnt bone, j in.
12. Dark earth, full of fragments of charcoal, Mytilus edulis, Patella vulgata,
Littorina littorea, and numerous bones, 8-9 in.
13. Sandy bed, with limestone fragments and rolled pebbles, 10 in.
14, Reddish clay, 2-3 in.
15. Sand, 6 in. 7
16, Sandy argillaceous bed, the base obscured by a talus of fragments, etc. from above.
Mello— Kitchen Middens in Wales. 535
_.The entire length of the Midden is about 80 yards, thinning out
at that distance into a dense bed of Puiella near the surface.
How far back from the shore it may extend is not so easy to ascer-
tain ; a bed of Littorina and Patella crops out on the
surface, about 56 yards from the commencement of Fic.2—Srction
the Midden, and 20 feet above the beach; at some six OF CLIFF, ABOUT
feet from the edge of the cliff, where it is exposed at aes ae
about three feet from the edge, the bed is six inches ,> Prey Morra
below the surface and two feet thick. I found no
bones here, but several fragments of charcoal. In
the cutting by the side of the pathway, near the gate
beyond the Dean of Christ Church’s house, a bed of
Patella and Littorina occurs about 50 or 60 feet from
the beach. Beside the shells mentioned above, I
found in bed No. 12 several oyster shells, two speci-
mens of Purpura lapillus and some fragments of
Cardium edule. The early inhabitants appear also
sometimes to have caught a crab, by way of a treat,
as part of a claw was in this bed. Amongst the bones
which J obtained were several that had been burnt;
others seem to have been split for the sake of the
marrow. ‘These burnt bones and shells, also calcined,
together with the large quantity of charcoal dissemi-
nated throughout these beds, seem to put beyond
question their being the remains of an old Kitchen
Midden, but I am inclined to doubt its very great
antiquity, many of the shells and bones, even in the
lowest bed, presenting a very fresh appearance, and
the latter seem, in many instances, to have lost none
of their gelatine ; however, that may prove nothing.
Bones were tolerably numerous in bed No. 12, but
no very large ones were met with. I found several
small jaws of lambs or small sheep; also fragments (talus).
of jaws of the ox and deer (species ?), two small
skulls of some little rodent, many leg bones, also vertebre and
knuckle bones of different small animals ;—what these may be I
am not enough of an osteologist to say. No traces of implements
appear in these beds, unless one small bone-fragment, which looks
as if it might have been used as an arrow-head, should prove one.
Bits of burnt clay, like those mentioned by Mr. Bonney, were very
numerous in parts, and the layer of burnt clay, with calcined pebbles,
looks very much—from the layer of charcoal on its surface—as if it
had been burnt i situ.
Farther along the coast, close to a boat-house, near the ruins of
Glogarth Abbey, a bed of Littorina and Patella appears in the cliff,
which is here but a few feet in height; the bed looks as if it had
been mostly destroyed, perhaps by the sea; in it I found a few bone-
fragments and teeth, and some bits of charcoal: the shells in this bed
were very friable, far more so than in the other Midden, owing
possibly to their greater antiquity, or, may be, to their being nearer
536 Belt—On the “ Lingula Flags.”
the surface, and thus more exposed to atmospheric influences. I ex-
amined as closely as possible the mussel-beds in the sand which caps
the Boulder-clay that appears on the coast higher up Conway Bay,
thinking they might perhaps turn out to be artificial accumulations ;
but I could discover no admixture of bones, or even of other shells
with them, with the exception of one or two specimens of Patella
and Iattorina. These mussel-shell beds occur in the loose sand, with
no rock for their attachment, and are about 20 feet above the beach
in some places. I could find nothing in the pocket of Mytilus near
the great Midden save those shells, and they mostly had their valves
in approximation and undisturbed; they are apparently unconnected
with the Midden. A general, though somewhat hasty search round
the greater part of the Orme failed to reveal any further traces of
Middens, although remains of raised beaches here and there, con-
taining a few shells, such as Patella, Littorina, etc., may be seen in
many places, and at very considerable heights above the present sea-
level. Some fissures also in the Limestone rocks can be traced in the
face of some of the quarries, which have been filled up with rolled
pebbles; these are now cemented into a firm conglomerate by the
infiltration of carbonate of lime. I could find no shells or other
organic remains in the contents of these fissures, though Patella and
LInttorina axe to be found in the talus close by.
[Norz.—All the bones sent me by the Rev. J. M. Mello, from the Kitchen Midden
in the Great Orme’s Head, were very much broken (old fractures) ; but I was enabled
to identify Bos longifrons; jaws, etc., of a small-horned sheep; Leg-bones of Canis
lupus, or Canis familiaris; tooth and vertebre of pig; and fragments of bones of
bird.—H.W.]
IV.—Own tHe “ Lineuna Frags,” orn “ Festiniog Group”
or THE DouGELLyY District.
By Tuomas Bztr, F.G.S.
[PART II.]
HE accompanying section shows the succession of beds from the
Harlech grits, near the sixth milestone on the road from Dolgelly
to 'Trawsfynydd, across their strike in a south-easterly direction, to
the lower ash-bed of the Arenig group at the farm of Blaenau, five
miles north-east from Dolgelly. In this section all the beds occur
in regular sequence, although they are invaded by many intrusive
masses and dykes of diabase;' only the larger of which are shown in
my section, as it would be impossible, on so small a scale to depict
the innumerable protrusions of this rock that occur in the district.
The section crosses, at Moel-Cors-y-garnedd, the southern flank of
the mountain Rhobell-fawr, which is the largest mass of diabase
in Wales. All along the eastern side of Rhobell-fawr the strata
are completely inverted, as shown in diagram, so that the Festiniog
beds (5 and 6) lie above the more recent Dolgelly beds (7 and 8),
from underneath which the Tremadoc beds (9) come up, overlying the
beds of slates and ashes belonging to the Arenig Group (10 and 11).
1 T follow Mr. David Forbes in calling these rocks diabase ; they are the ‘‘ Green-
stones” of the Geological Survey. ‘
e
5387
Belt—On the “ Lingula Flags.”
SF tanaveen=mmase~-~—- TDolgelly and Trawsfynydd Road.
24
N.W.
Afon Eden.
Afon Mawddach
ead
Z
1, Harlech Grits.
2. Menevian Beds.
8. Lower Maentwrog Beds.
4, Upper Maentwrog Beds.
Suction From AFoN EpEN To BLAENAU, FIVE MILES N.E, From DoLcELLy.
tosses ee rte ea + er Blaenau.
8.E.
cs}
a]
E
hy
‘
: the
s 5
i) ‘ a
=| = Lo] ro)
Ro) 3 8 2
a | a pa
{ : t
$ ; B
' '
5 a i
( y ‘
1 ’ »
t : '
{ ‘ y
H '
4 »
:
{ y
' e
SG 4yhe In A 74
LEA is AARC oan
P Fz
5. Lower Festiniog Beds. 9. Tremadoc Beds.
6. Upper Festiniog Beds. 10. Arenig Beds.
7. Lower Dolgelly Beds. 1]. Ash Beds.
8. Upper Dolgelly Beds. D. Intrusive Diabase.
538 Belt—On the “ Lingula Flags.”
I shall now describe the strata lying between the Menevian and
Tremadoc beds in ascending order.
Marntwrog Group.
Lower Maentwrog Beds (No. 3 in Section).—The blue black slates
of the Menevian group, which everywhere around the Merioneth-
shire anti-clinal overlie conformably the Harlech grits, are followed
by a series of sandy and slaty beds. The lowest of these are grey
and yellowish grey, fine-grained, pyritic flags, with hard felspathic
bands and rusty partings. Alternations of more arenaceous and
gritty beds are not unfrequent, and beds of yellow grey shale also
occur. Some of the beds are ripple-marked and traversed by worm-
tracks, but neither Trilobites nor shells have been found.
These arenaceous and shaly flags are about 400 feet thick, and are
succeeded by bluish grey, blue, and blue-black, jointed, fossiliferous
slates, alternating with bands of slightly arenaceous, grey and yellow
grey flags. The slates contain Olenus gibbosus, Wahl ; Agnostus
nodosus, Belt; and A. pisiformis, Lin., var. obesus, Belt. Fragments
of these fossils were first found by Mr. Williamson, near Cefn-
deuddwr in 1864; but it was not until Mr. Barlow found them in
great abundance near Dolmelynllyn in 1866 that I was able to
determine their specific distinctness, and to separate the beds con-
taining them from those above, with which they had been until then
confounded.
The fossiliferous beds, and also the underlying arenaceous and
shaly flags, may be well studied on the range between the Eden and
the Mawddach, a little above the junction of these rivers, but the
best locality for the fossils is that discovered by Mr. Barlow, near
Dolmelynllyn, in the Mawddach, opposite the fifth milestone on the
Trawsfynydd road.
The fossiliferous beds are about 300 feet thick, making the total
thickness of the Lower Maentwrog beds about 700 feet.
Upper Maentwrog Beds (No. 4 in Section).—The last beds are
overlaid by yellow and bluish grey fine grained flags, sometimes
a little arenaceous, but never so coarse as some of the gritty beds
lying below. © They are often finely laminated and flaky, especially
towards their upper limit, where Agnostus pisiformis, Lin., is not
uncommon. The top beds are very fine grained and flaky, and of a
bluish or brownish grey colour. There are about 600 feet of these
fine grained flags. :
From the bluish grey beds there is a gradual passage upwards
into dark, dull blue slates, much jointed and weathering to a rusty
colour. There are occasional intercalations of bluish and yellowish
grey beds; and where sections of the rocks are exposed in the beds
of streams, thin alternations of blue, yellow, and grey layers give
them a banded appearance. This part of the series is at least 1200
feet thick, and may be more. ‘The rocks are so much faulted that it
is impossible to obtain more than an approximation towards correct
measurements.
Throughout the blue beds Agnostus pisiformis, Lin. is found, but
Belt—On the “ Lingula Flags.” 539
most abundantly at the base and in the upper beds. Above Dol-
goed, in thin shaly slates, it occurs in thousands, all drawn out
and distorted by slaty cleavage; but the best specimens have been
found on the left bank of the Mawddach below Hafod-fraith. In the
Lower beds, at Cae-gwernog above Llanelltyd, where it was first
found by Mr. Salter in 1864, and near Dolgoed, Olenus truncatus,
Ang. accompanies the Agnostus, but it does not follow it into the
higher beds, where it is replaced by a closely-allied species, O. cata-
ractes, Salter, of which I have obtained fragments from the rocks by
the roadside, a little north of Llanelltyd, and in the blue slates
below Hafod-fraith.
The total thickness of the Upper Maentwrog beds in the Dolgelly
and Maentwrog districts is about 1800 feet.
The Maentwrog Group, comprising the Upper and Lower Maent-
wrog beds, contains altogether, in the district under consideration,
about 2500 feet of strata, and is, as has been already mentioned,
well defined, both lithologically and paleontologically. The beds
are everywhere much jointed and weather to a rusty colour, and
form hills covered with angular ferruginous débris, so that even at
a distance the experienced eye can distinguish them from the hard,
shelving flags of the Festiniog Group, or the low rounded hills
formed from the much softer slates of the Dolgelly Group.
In the Dolgelly district the slates and shaly flags of the Maent-
wrog Group occupy all the ground between the Menevian beds and
the river Mawddach, from a little above Barmouth up to Llanelltyd,
where they cross the river and occupy both its banks as far as
Tyddyngwladis Mine. A little below the Tyddyngwladis lode they
are thrown entirely to the eastern side of the river, partly by
intrusions of diabase and partly by faults. Between Cwmhesian
Mine and Hafod-fraith they again cross the river and range north-
ward, towards Trawsfynydd.
In the Maentwrog district these beds are finely developed, and
splendid sections of them are shown in the Waterfall Valley, and in
the valley running from Tafarn-helig to Caen-y-coed. In the Caen-
y-coed quarries (now abandoned) the topmost beds are well ex-
hibited, and from this locality the finest specimens of O. caturactes,
Salter, have been obtained by Mr. Homfray, who has also found with
it, fragments of a crustacean allied to Hymenocaris.
The rocks of the Maentwrog Group are of little economic im-
portance. Some rough slates and slabs have been worked in them
at Caen-y-coed and above Llanelltyd, but the fine-grained beds are
too much jointed, and the coarse-grained too rough for profitable
working. The gold-mines of Hafod-y-morfa, Cefn-deuddwr, and
others of less importance have been opened in these beds. The
auriferous quartz veins also contain ores of copper, lead, and zine,
but only in small quantities.
Festiniocg Grovr.
Lower Festiniog Beds (No. 5 in Section).—Lying conformably upon
the Upper Maentwrog beds are a thick series of micaceous, grey
540 Belt—On the “ Lingula Flags.”
flags. The Lower beds are bluish grey and only slightly arenaceous
and micaceous, and contain Lingulella Davisiit, MeCoy, in abundance,
and also numerous worm tracks. Thin, hard felspathic layers
alternate with thicker and more shaly ones. These are succeeded
by thick beds of yellow and yellowish grey arenaceous flags, con-
taining also hard felspathic layers. The arenaceous beds are often
coarsely and strongly cleaved, and the cleavage planes filled with
iron rust, so that, but for the uncleaved interbedded felspathic layers,
it would be most difficult to determine the planes of bedding, and
those of cleavage might easily be mistaken for them. Lingulella
Davisii occurs only sparingly in this part of the series. The thick-
bedded arenaceous flags are followed by thinner-bedded grey and
yellowish grey flags, much finer grained than those lying below
them, and crowded with the shells of Lingulella Davisit. In these
beds in 1865 I found, near Penmaen-pool, the only specimen of a
true fucus recorded from British Lower Silurian or Cambrian rocks.
It branched dichotomously over the face of a slab about four feet
long and three feet broad. It belongs to the genius Buthotrephis, but
the species has not yet been described.
The highest of the Lower Festiniog beds are bluish and brownish
grey fine-grained flags. They too are crowded with Lingulella
Davisii, and contain also Hymenocaris vermicauda, Salter, which has
been found near Penmaen-pool, on Mynydd-gader and on Moel
Hafod-Owen, but only sparingly. 'The Lower Festiniog beds are
about 2000 feet thick.
Upper Festiniog Beds (No. 6 in Section).—Lyimg on the last-
named beds is a band of tough blue grey flags, not more than fifty
feet thick, but containing an assemblage of fossil remains, nearly
distinct from those in the beds below, and quite so from those above.
A species of Lingulella, probably a variety of L. Dawisit, but only one-
third the size of that species, still occurs, and is accompanied by
Hymenocaris vermicauda. Along with these occur, for the first time,
Conocoryphe micruua, Salter, and Bellerophon Cambriensis, Sp.n. I
have found this band, with its characteristic fossils, at Gwern-y-
barcud ; in the Mawddach near Craig-y-dinas, and on Mynydd-gader.
The Festiniog Group, as above defined, comprises the Upper and
Lower Festiniog beds, and is a little more than 2000 feet thick.
The river Mawddach cuts through the whole of the beds between
Rhiufelyn and Hafod-fraith. From thence they range across the
east-end of Moel Hafod-Owen and by Pen-y-bryn, skirting the
igneous rocks of Rhobell-fawr, where, however, only the lower beds
are seen, as the upper ones have been thrust a mile and a half
over to the eastward, by the intrusion of the diabase, and are seen
on the east flank of Moel Cors-y-garnedd completely inverted, so
that they overlie the newer Dolgelly and Tremadoc beds, as shown in
Section, page 537. From Pen-y-bryn the lower beds, much disturbed
by intrusive rocks, run south-westerly past Glasdir-isaf and Llyn
Cynwch to Tyddyn-bach, but are not well seen, excepting on the
west bank of the lake, where good specimens of Lingulella Davisiw
abound. ‘The whole of the beds, having escaped from the disturb-
Belt—On the “ Lingula Flags.” O41
ing influence of the Rhobell-fawr igneous rocks, cross the Wnion near
Glyn Maldon, and then by Gwern-y-barcud and Tyn-y-craig, range
to Coed-y-garth, and into the estuary of the Mawddach. To the
south of Dolgelly, at Pandy and Bryn-rhug, they are brought in by a
branch of the great Bala fault, and are there much disturbed and
altered by intrusive igneous rocks.
Very durable building stones and some good rough flags are
obtained from these strata. In the neighbourhood of the intrusive
diabases the lower beds are often largely impregnated with iron and
copper pyrites, and have been mined for the latter with some
success at Glasdir. The numerous quartz veins intersecting the
same beds in the neighbourhood of Dol-y-frwynog all contain a
little gold, but have nowhere on this horizon been worked with
profit.
DoiGgeLty GRovP.
Lower Dolgeily Beds (No. 7 in Section).—The next beds in
ascending order are hard, blue slates, characterized by containing,
in great abundance, a small species of Orthis, and Parabolina ( Olenus)
spinulosa, Wahl. P. spinulosa was first found in the Dolgelly dis-
trict by Mr. Williamson, in loose boulders, in the valley of the
Mawddach, below Rhiw-felyn. In consequence of this discovery we
searched the rocks in the neighbourhood together, and soon found,
not only the above fossils i situ, but, above the strata contain-
ing them, the Upper Dolgelly beds crowded in some parts with
Trilobites of various genera. Shortly after, I found the lower beds
with Orthis and P. spinulosa at Gwern-y-barcud, and more lately,
have detected them on Mynydd Gader, at both places lying con-
formably upon the Upper Festiniog beds. I have also recognised
them on the eastern flank of Moel Cors-y-Garnedd; but there,
through the inversion of the strata, they lie below instead of above
the Upper Festiniog beds. Since their discovery, the lower beds
have been well searched for fossils; but the only species found
in addition to the two mentioned above, have been some speci-
mens of a Jangulella, and a single fragment of a species of Ag-
nostus. In a loose stone, which probably came from these beds,
Mr. Hicks, of St. David’s, found a species of Protospongia. It adds
to the probability that the specimen came from the Lower Dolgelly
beds—that I have found two species of the same genus in Lower
Tremadoc beds—so that it must have existed from the Menevian
epoch, where it first appears, up to the time of the deposition of the
Tremadoc strata.
I think that the Lower Dolgelly beds are about three hundred feet
thick ; but they are so much jointed and faulted that I have nowhere
been able to get a trustworthy measurement of them, and my estimate
of their thickness is little more than a guess.
Upper Dolgelly Beds (No. 8 in Section).—To these beds I have
already alluded, when mentioning the discovery of the last. They
are soft, black slates, much jointed and often intensely cleaved.
They generally contain numerous fine grains of pisolitic iron. Near
542 Belt—On the “ Lingula Flags.”
the junction with the lower blue beds some bands of blue slate
occur, interstratified with the black, but higher up they are entirely
black. With the exception of a thin layer of black slate in the
Festiniog Group, and which has been noticed but at one spot, the
Upper Dolgelly beds are the only black slates in the district, although
the term has been applied to the dark blue rocks of the Menevian
and Maentwrog Groups. ‘These, however, are never black, and
when scratched show a white streak. ‘The Upper Dolgelly beds are
not only black, but their streak also is black. A careful examination
of all the rocks of the Dolgelly district enables me to state that,
with the trivial exception mentioned above, there are no other beds
with a black streak. It is only since I established this fact that I
have been able to map out the beds in the highly disturbed district
to the east of Rhobell-fawr, and on Mynydd Gader. Geologists
who have attempted to unravel the intricacies of such a disturbed
country as that around Dolgelly, where the strata are faulted and
contorted, altered by intrusive igneous rocks, and often so shattered
and cleaved that it is useless to search for fossils, will appreciate the
value of the discovery of a test which enables us to identify a well-
defined set of strata however it may be fractured and cleaved.
The Upper Dolgelly beds are characterized by a great many
Trilobites, none of which are found in the strata above or below. The
species found in the Dolgelly district are Conocoryphe (solenpleura ?)
abdita, Sal., C. Williamsonii, sp. u., C. longispina, sp. n., Peltura
scarabeoides, Wahl., Spherophthalmus bisulcatus, Phil., S. humilis, Phil.,
Agnostus princeps, Sal., A. trisectus, Sal., and A. obtusus, sp.n. Besides
the trilobites, a few shells belonging to the genera Orthis, Lingulella,
and Obolella, are found. The Orthis is O. lenticularis, Dalm., ac-
cording to Salter; but the others have not been described. The
Lingulella is, however, very like L. Davisii, McCoy, from the Festiniog
beds.
Near Tremadoc the following additional Trilobites have been found
in strata at or about the same horizon as the above :—Conocoryphe
invita, Sal., Dikelocephalus (?) celticus, Sal., and D. (?) discoidalis, Sal.
The Upper Dolgelly beds are about three hundred feet thick.
The Dolgelly Group, comprising the Upper and Lower Dolgelly
beds, is altogether about six hundred feet thick. A very fine section
of the beds is exposed along a brook falling into the Mawddach at
Rhiw-felyn. From thence, with many dislocations, they curve round
the eastern side of Rhobell-fawr to Blaenau. Half amile south-west
from Dolgelly the black beds are well developed up the ravine through
the grounds of. Bryn-y-gwin to Bran-y-gader. where they are over-
laid by Lower Tremador beds, with Dictyonema fenestrata, Sal. On
Mynydd Gader they overlie the Upper Festiniog beds, and are
followed conformably by Tremadoe strata containing Asaphus in-
notatus, Sal., Niobe Homfrayi, Sal., Conocoryphe depressa, Sal., and two
species of Protospongia.
The Lower beds are not known to exist except in the Dolgelly
district. They will, however, probably be discovered around Tre-
madoc, as in the Jermyn Street Museum there is a tail of Parabolina
Saunders— Geology of South Beds. 543
spinulosa, Wahl. (labelled Olenus serratus, Sal.), from Carreg-wen,
near Tremadoc.
The Upper beds have long been known as the Malvern shales,
and I should have preferred to call the group the Malvern Group, if
the lower beds had been found in that locality. It is, however,
appropriate that the Dolgelly district, where alone the whole of
the Cambrian rocks known in Great Britain are represented, should
give a name to one of the groups.
(To be continued).
V.—Norrs on tat Grotocy or Sours Bzps.
(No. IT.)
By J. Saunprrs, Esq.
INCE my former communication on this subject, which appeared
in the GronocicaL Macazine for April last, (p. 154) I have
had several opportunities of re-visiting some of the cuttings, on the
Midland Railway, therein referred to, respecting which some doubts
were expressed in reference to the age of the deposits exposed to
view, and, as they are now completed, more precise observations can be
made than when they were only just commenced. The cutting,
south-east from Westoning, (which, in an Hditorial note, was sug-
gested might be of Tertiary age) exposes a dark heavy clay, which,
upon the most rigid examination, furnished not the least trace of
rolled fragments of Chalk or flints, or any other substance so fre-
quent in the Tertiary clays of this neighbourhood, which would lead
to the inference that it had been deposited subsequently to the Cre-
taceous era. It, however, contains what would strongly indicate
that it is cowval with the Greensand, namely, a continuous band of
coprolitic nodules, averaging about a foot in thickness. This layer
passes through about one-third of the cutting, and may be traced
from its commencement on the north-west side of the hill, passing
along the face of the cutting with a gentle dip, until it reaches the
level of the line, when it passes out of sight, nor does it re-appear
on the south-east side of the excavation. The fossils associated with
the nodules are Lamna, Belemnites, Parasmilia, and Terebratule, all
of which are abundant in the coprolite beds at Hexton and other
places in the immediate vicinity. Both above and below the copro-
lites the clay is identical in character, and must have been deposited
contemporaneously with its associated nodules, and, as far as I can
judge, it is the equivalent of the bed h of the section given by Mr. W.
Whitaker, in the Quart. Journ. Geol. Soc., vol. xxi., 1865, pp. 399,
“On the Chalk of Bucks.” About the middle of the cutting is a con-
siderable accumulation of light-brown coloured drift-sands, that lie
in a basin-like hollow, that has been eroded from the summit of the
hill.
The cutting at Harlington, at the north-west side of the hill, facing
the Kimmeridge Clay and Greensand strata, exposes a thick bed of
heavy dark clay, containing a profusion of selenite crystals, with
544 Saunders— Geology of South Beds.
occasional fragments of rolled chalk, indicating that it has been
formed principally from the disintegration of the Kimmeridge bed.
It furnished several fossils identical with those observed in this form-
ation at Ampthill, at which place also selenite crystals form a con-
siderable portion of the mass of the upper beds. This bed of dark
clay is succeeded by others of a lighter colour, containing a greater
proportion of rolled Chalk and flints, until at the south-east side of
the hill—or that facing the Chalk escarpment—the beds are com-
posed almost entirely of sand and water-worn fragments from the
Upper Cretaceous beds.
The cuttings between Luton and New Mill End, running parallel
with Luton Hoo Park, exhibit some fine specimens of ‘“ Chalk-rock ”
which are interesting, as few continuous sections of this remarkable
formation are visible. The first cutting, about a mile from Luton,
is entirely in ‘‘ Chalk-with-flints,” which is here very massive. In
the second cutting we have the first occurrence of the ‘“ Chalk-rock,”
where are exhibited in descending order :—
Chalk-with-flints, 10 feet to 15 feet.
- Chalk-rock, about 2 feet.
Lower Chalk, without flints, 10 feet to 15 feet.
So excessively hard is this “rock” that it stands out in striking
prominence on the sides of the excavation, it having been im-
practicahle to level it to the same plane as the softer strata above
and below. It does not occur in unbroken continuity, but is con-
siderably dislocated at several places, and sometimes, for a few
yards, two beds lie parallel to each other at a distance of several
feet.
Contrary to the general character of this bed in other localities—
as observed by Mr. Whitaker and others—it is here very rich in
fossils; but, the matrix being so excessively hard, they are with
great difficulty extracted. It has a metallic ring when struck with
a hammer; it abounds in green-coated nodules, and is not uniformly
compact, but in places can be very easily pulverized. Perforations
are occasionally to be seen passing almost through its entire thickness,
which have been subsequently filled with dark-brown clay. The
Brachiopods, Echinoderms, etc., are always in good preservation,
but the more delicate shells of the univalves have perished, leaving
casts of their external ornamentation, and a spiral mould of their
interior. The Ammonitide and Nautili have also experienced a
similar decay, and, when broken, show the internal divisions of
their septa. From my experience in this district I consider that the
fossils from this bed have a greater resemblance to those of the
Lower Chalk, than to the Upper, or Chalk-with-flints. The following
are the principal genera obtained from the section :—
Ventriculttes. Cidaris. Terebratula. Ammonites.
Cephalites. Cyphosoma. Rhynconella. Nautilus,
Parasmilia Serpula. Pleurotmaria. Lamna.
Holaster. Spondylus. Turbo. Ptychodus.
Of some of these genera there are several species which await the
skill of the Palzontologist to determine.
Miss Eyton—On Glacio-Marine Denudation. 045°
‘In the third cutting the Chalk-rock occurs at a less elevation, so
that a smaller section of the Lower Chalk is seen beneath it; and
in the fourth cutting, immediately adjoining the village of New Mill
End, it occurs at the bottom of the excavation, which in the deepest
part is about ten or twelve feet. This formation also occurs in the
immediate vicinity of Luton, on the opposite side of the valley of
the Lea. It has been met with in two Chalk-pits now closed,
in one of which, near the London Road, it was customary to
sink a shaft down to this bed, and then excavate a considerable
chamber beneath, the Chalk-rock forming an excellent roof to the
workings.
Through the kind assistance of R. Htheridge, Esq., Paleeontologist
to the Geological Survey, I am enabled to add the-following species,
from the Totternhoe stone, to the list published in the April Number
of the Gronocicat Macazine (p. 159) :—
Rhynchonella plicatula. Exogyra.
“5 Cuvier. Paleastacus.
" octoplicata. Plesiosaurus campylodon.
VL—Own tur Guacio-Maringe DENUDATION OF CERTAIN DistRIcTs.
By Miss Eyton.
AVING been for the last twelve months engaged in a careful
study of the post-Tertiary geology of the eastern part of Shrop-
shire, I have at length arrived at the conclusion that the denudation
of the New Red Sandstone in this neighbourhood, and consequent
excavation of the Tern basin, has been effected partly by glacial and
partly by marine agency ; the grounds upon which this conclusion
is based being :—(1) An attentive consideration of the general form
and outline of the basin; (2) A particular examination of the drift
beds contained therein.
First, with regard to the general outline. The district drained by
the river Tern, forms a basin of extensive area, but with a compara-
tively narrow outlet. The area is almost entirely of New Red
Sandstone, chiefly the Lower Biinter beds, bounded on the east
- by the basaltic rock of the Wrekin range of hills, and by the long
line of low Coal-measure hills extending through Ketley, Donning-
ton Wood, and Lilleshall, in the direction of Staffordshire. In fact,
as will be seen by consulting the Ordnance map, the outline of the
basin is here co-extensive with the line of fault separating the
Biinter Sandstone from the Coal-field. On the opposite side of the
latter there occurs another great fault, dividing the Coal from the
Permian beds, and by sinking a shaft through the latter, the Coal
was again found on the lower side of the fault. It is extremely
probable that the same experiment might be attended with similar
success in the Tern basin. Indeed, there can be little doubt that,
before the period of volcanic convulsion, which occasioned the faults,
both the Permian and lower Biinter beds covered the whole of the
Shropshire Coal-field, and it is probable that even since that period
VOL, IV.—NO, XLII. 36
546 Miss Eyton—On Glacio-Marine Denudation.
they have been largely denuded by glacial and marine agency ; s0
that, if we are indebted to the god Pluto for having opened to us
his stores of subterranean wealth, his brother deity, Neptune, may
claim a share of our gratitude for having, by more gentle means, re-
moved some of the obstacles to its acquisition.
The western boundary of the basin is formed by the basaltic
ridge of Haughmond Hill, which, with its opposite neighbuur, the
Wrekin, form the barriers on either side of the outlet. After this
ridge is passed the basin widens considerably, and the outline is, in
places, broken. It is, however, perfectly distinct in the Sandstone
Hills of Grinshill, and in the neighbourhood of Hawkestone.
In the lowest part of the area there lies an old lake basin, some
seven miles in length, by four in width, now called the Wealdmoors,’
and it is upon the evidence of this basin that the glacial theory
principally depends. I am at a loss to conceive any other denuding
agent than ice, with sufficient force to act upon so large an extent of
surface ‘in a circular direction. It must be remembered that the
Wealdmoors certainly existed as a lake at the period of the Low-
level drifts, and, consequently, that the excavation must have been
effected previously to that period; that is to say, either during the
period of marine submergence, or before it. Now the action of the
sea is always in straight lines: it may form cliffs, terraces, or lines
of shingle, but it is incapable of working in a circular direction, save
in the exceptional case of a whirlpool, or a concentration of local
currents, flowing from various directions; and to produce either of
these, there must be some local cause, as sunken rocks, of which
there is no trace in this instance. I infer, therefore, that the de-
pression in question was produced by a mass of frozen matter, which,
being heaviest in the centre, was continually pressing the lower
fragments outwards, and from which small streams of water were
continually flowing at the lowest point of contact with the earth.
Tf, as Mr. H. Hull has demonstrated,’ a valley within a valley is a
proof that the outer one is of marine origin, I think a basin within a
basin may be taken to show the same with regard to ice. The
Wrekin must certainly have once formed an ice-shed. Between the
Ercall and Lawrence’s Hill, in the Wrekin chain, there occurs a deep
rift, now occupied by a small mountain stream, but when we con-
sider the hardness of the rock through which the channel is cut, it
seems scarcely possible that such a rivulet could have effected it.
Besides, the chasm is strewn with large masses of rock, firmly fixed
in the mud and gravel, brought down annually by the stream, and
overgrown with vegetation; evidently the remains of a far older
drift. Other ice-rifts occur in this chain of hills. On the face of
Haughmond Hill, towards the Severn, are four or five distinct
furrows, or grooves, apparently ploughed into the hill by masses of
frozen matter precipitating themselves into the valley below.
I have not yet succeeded in finding any beds of ascertained glacial
drift in the basin itself, but there are traces of its existence in the
1 See Grotocican Macazine for January, 1867, for a detailed account.
? Modern views of denudation. Popular Science Review, Oct., 1866.
Miss Eyton—On Glacio-Marine Denudation. 047
large granite and limestone boulders, which are scattered at different
levels over the surface of the land. And this is easily accounted for
when we consider that, during the succeeding period of submergence,
all the lighter material would be washed away by the waves, to re-
appear in the form of marine drift, the heavy boulders alone remain-
ing in, or near, their original sites.
It is, however, certain, that if the Tern basin was originally
excavated by ice, the sea must, at least, have done much towards
shaping and modifying its outline. ‘To the eye of a geologist, look-
ing from the centre of the depression above alluded to, it is easy to
re-picture the time when the whole of the surrounding country, with
its rich pastures, its towns and rural homesteads, and its busy work-
ing population, was a vast bay or inland sea, resembling the Irish
Loughs of the present day, having its outlet into the Severn sea at
the northern extremity between the two before mentioned basaltic
barriers. The coast line, though not in all places equally distinct,
may yet be traced almost continuously ; and nowhere more clearly
than in the terrace of Haughmond Hill. Had the denudation of the
Sandstone been entirely effected in this locality by ice, it would have
left its marks, in the shape of furrows and striz, upon the hill-side ;
but none such exist. On the contrary, the hill forms a terrace ex-
tending in a direct line, with smooth and rounded outlines, such as
could only have been formed by the continuous and gradual action of
the waves, wearing away the softer rock which then concealed the
face of the hill, leaving bare the basaltic ridge. The same obser-
vations apply wherever trap intrusions occur, as at Lilleshall and
Wrockardine Hill.
But it is in the Drifts that we find the strongest evidence of the
sea’s presence. The lowest of these consists of a bed of loose
coarse-grained sand, partially fillmg up the hollows over nearly the
whole extent of the basin, and sometimes appearing upon the sides
and summits of the lower elevations. I infer that this bed is of
marine origin, since the uniform action of the sea could alone have
distributed it so evenly and generally over so large a surface. |
When microscopically examined it is found not to consist chiefly of
the denuded sandstone, but of minute rounded fragments of quartz,
syenite, and greenstone. It has not hitherto yielded any organic
remains.
Reposing conformably upon this, and extending along the base of
the Wrekin chain, and of the Carboniferous hills, is a line of marine
drift clearly indicating an old sea-board. ‘This drift consists of
clay, mixed with rounded shingle, slightly bedded. An admirable
section is exposed to view in the clay-pit worked by Mr. More, of
Ketley Brook. The face of the bank, which is here rather steep,
has been cut away, so that the position of the beds, shingly-clay resting
upon sand, is visible. A curious sub-atmospheric effect occurs here,
which, although foreign to the present subject, is so remarkable ag
to be worth mentioning. The rain, penetrating the upper bed, has
formed small streams trickling through into the sand, and carrying
particles of the clay with it, to which the sand adhering, columnar
548 Miss Eyton—On Glacio-Marine Denudation.
masses have been formed of a substance as hard as the hardest
sandstone.
This bed is some hundred feet, more or less, below the level of
the Glacial chasms I have spoken of; but we often find, mixed with
the round shingle, angular débris which may have been washed
down by former streams now vanished, or by melting snows. I
am inclined to believe the latter, and to see in these drifts a line of
partition above which we may find the remains of an ancient frigid
zone ; while below them we find traces of a gradually increasing
temperature. Specimens of Turritella communis, T. incrassata, and
a small Tellina, have been found in different localities along this
line. This bed occurs at about the same elevation and in the same
position as those drifts which mark the old coast-line along the
eastern base of the Malvern Hills, and I am satisfied with their
correlation. Thus the Tern basin was contemporary with, and, in
fact, formed a part of, the ancient Severn sea.
Proceeding lower in the descending scale, we find that the river
Tern, a small sluggish stream, whose course lies exclusively through
sandstone and Lias, and which overflows its banks at every heavy
rain or thaw, so shallow is its channel, is yet bordered at a height
of about eighteen or twenty feet by banks of shingle, consisting
of such a heterogeneous mixture of materials that it is out of reason
to suppose them all to have been collected by the river, although
they may have been re-assorted and placed in their present position
by a former and more powerful stream. Grey granite, which must
have been carried southward from Cumberland, with occasional
fragments of pink and micaceous granite, and flints much chipped
and rolled, enter into its composition. All these appear to have
undergone a process of scratching and grinding, more forcible than
anything the river could have effected, and must, I think, be the
remains of an old glacial drift, brought here by the waves and
afterwards arranged and placed by the ancient stream and its
tributary brooks.
And here we find the agency of the latter at work. Passing
down from the hills through the high-level drifts on their way to
the plain, they would convey by their rapid current, much of the
material to the river, separating the shingle from the commingled
clay and silt in preparation for the sorting and bedding process,
to which it is next subjected. Taking into consideration the hard-
ness of some of the material, and the immense amount of attrition
which it must have taken to bring some of the pebbles to their
present form, there seems no alternative but to suppose it the result
of some such process.
T have thus endeavoured to describe the means by which some of
the more extensive depressions which vary the surface of our country
have been formed. The same observations will generally apply to
those wide and deep valleys through which no river of any size has
its course, as the vale of Church Stretton, in Shropshire, and of
Todmorden in Yorkshire. Nature has her factories and her mining
operations as well as man, only they are upon so vast a scale and the
Chambers—‘ Eskar’ at St. Fort. 549
interval of time consumed is so immense, that our insect eyes are often
as incapable of discerning, as our minds of grasping, the facts which
she lays before us. It is only by a long and close process of reason-
ing that we can arrive at the solution of a single problem.
SECTION OF THE TERN VALLEY SHOWING THE RELATIVE POSITIONS OF THE
DRIFT-BEDS.
1300 feet. 250 feet. 20 feet. 20 feet.
FIA
) Summit of ths Wrekin. (e) Clay under peat, lake basin.
6) High level drifts, on Red Sandstone. (f) Present river-level.
(c) Protrusion of Basaltic rock. (g) Low-level drift.
(d) Sand. (a) Bank of river valley.
The accompanying diagram shows the relative positions of the
Drift-beds I have described. Although not, perhaps, strictly correct,
it is so nearly so as to afford a sufficient guide to any geologist
desirous to examine these beds.
INFO ERE SssS) (Gn) Ae Oum sys
GronogicaL PAPERS READ BEFORE THE BritisH ASSOCIATION, AT
DUNDEE.
I.—Norrce or an “Esxar” at Sr. Fort, Firesuirz. By
Dr. Rosert CHampers, F.R.S.E., F.G.S.
SKARS, though of frequent occurrence in Ireland, and very
numerous in Sweden, where they are recognised by the plural
word “désar,” are comparatively rare in Scotland. One of a very
striking character occurs about three miles inland from Newport, on
the road from Dundee to Cupar-Fife, and on the estate of Mr.
Stewart, of St. Fort. It is fully a mile long, and in some parts half
a mile broad; rises from thirty to forty feet above the neighbouring
ground, and is, unfortunately for the geologist, wholly covered with
trees. Its surface is rough and uneven. Several good sections, pro-
duced by the cuttings for the road to Kilmany, show it to be com-
posed of gravel chiefly rounded, including many large pieces, some
of which are of Primitive rocks. The skirts of this “eskar” melt
into a vast gravelly tract of cultivated ground, undulating towards
Balmerino, but in other directions forming flat surfaces on a higher
level. Elsewhere there are gravel mounts of less elevation, with
rounded tops. The whole are manifestly relics of a vast sheet of
alluvium at between eighty or ninety feet above the present level
of the sea, extending southward into the valley of the Eden, and
thence eastward by Kincaple and Strathtyrum to St. Andrews. 'The
history of this great sheet of alluvium is probably connected with
500 Home—Old Sea-Cliffs, etc., of the Firth of Forth.
Glacial action in the Tay, in the upper part of which, about Weem,
there are decided moraines. In most of the great outlets from the
Alpine regions of Scotland—as, for example, the valleys of the
Spey, the Findhorn, and the Ness—there are smaller sheets of
gravelly alluvium gathered about the places where the valleys open
into the low country. In the case of the alluvial sheet here de-
scribed, there has been sufficient denudation and outsweeping to
account for the sand-banks which so largely encumber the mouth of
the Tay, and give so much trouble to the mariners of Dundee.
I1.—Ow tHe Oxp Sra Currrs anp SupmaARINE Banxs or THE FIRTH
or Forts. By D. Mitne Home, F.R.S.H., F.G.S.
N describing the line of old sea-cliff along both sides of the Firth
of Forth, which had been formed before the last change in the
relative levels of sea and land, Mr. Home stated that its height at
the lower parts of the estuary was about thirteen or fourteen feet
above the present level of the sea, whilst near Stirling it was about
thirty-one feet, and to the west about thirty-five or forty feet. He
also specified two higher and older cliffs at heights of about sixty feet
and one hundred and thirty feet respectively. Skeletons of whales
and seals had been found at heights varying from eighteen to twenty-
three feet above the present level of high-water-mark, and sea shells
were found in two conditions—viz., first, in undisturbed beds, now
fourteen and fifteen feet above high-water-mark, entire and perfect ;
and, secondly. in beaches, where they were broken. He explained
the origin of the Hstuary of the Firth, by the great east and west
fractures in the country adjoining, to the north and south. He said
that in the Fife Coal-field, the downcasts were almost all on the
south side of the fractures, and amounted altogether to nearly 2,000
feet ; and in the Coal-field of the Lothians, Linlithgow, and Stirling-
shire, the downcasts were, on the other hand, to the north, and even
to a greater extent, thus producing a trough or hollow, now filled
by an arm of the sea. The rocks in this hollow were covered by
various drift deposits, the oldest being Boulder-clay, and, over it,
stratified clay, sand, or gravel. The gravel was generally on the
top, which was accounted for by the water of the Estuary shallowing,
whereby the currents became more powerful, and thus gravel was
laid down where only mud or sand could be laid down before. Mr.
M. Home next proceeded to describe a long ridge of gravel running
four or five miles through Callendar Park, by Polmont eastward
towards Linlithgow. He stated that its height was from thirty to
sixty feet, and, judging from the materials composing it, he con-
sidered it had been formed by sea-currents. He said that these
gravel ridges were very numerous in our open valleys, and that
their direction or course was invariably parallel with the axis or
sides of the valley. Though he had not seen the ridge of gravel at
St. Fort, described in Dr. Chambers’s paper, he could not help think-
ing it was to be accounted for in the same way, viz., by marine
Wiinsch—Fossil Trees in Arran. 551
currents, and not as an effect of ice action. He exhibited some
Admiralty charts, showing the submarine banks and spits existing
in the English Channel, all of which were in like manner parallel
to the sea-coast. If this bank was formed in that way, the sea must
have stood at least 350 feet higher than now, and, in that view, an
explanation was afforded of several phenomena in the district, such
as the smoothed appearance of the hard whinstone rocks of Stirling,
Craigforth, Airthrey, Castleton, and Logie. He thought it however
probable that ice then floated on the sea, otherwise he could not
account for the position of some enormous boulders to the east of
Stirling. In the opinion recently expressed, that the last change of
relative levels between sea and land had occurred since the occupa-
tion of this country by the Romans, he could not concur. Several
facts militated against it. If the sea covered the extensive plains to
the west of Stirling, up to the old sea-cliff shown on the map, it
would have been impossible for the Romans to have had their road,
which had been discovered across the moss of Kincardine; or to
have had their fort on the banks of the river below Stirling. More-
over, the caves hollowed out by the sea at Wemyss, in Fife, before
the last change of the relative levels, must then have been occupied
by the sea, and therefore the remarkable sculptures found on their
walls, lately described by Sir James Simpson, must have been ex-
ecuted since the Romans left our island, a notion which, he believed,
all archeologists would repudiate.
T1I.—On Carponirerous Fossizr Trees EmMBeppEep IN TRAPPEAN
AsH IN THE IstE oF Arran.—By EH. A. Wounscu, Hsq.
HE beds in which these trees occur have hitherto been classified
as trap dykes or eruptive sheets of trap rock, but a summer’s
residence in the island has enabled Mr. Wiinsch to discover the true
character of the rocks. The beds referred to extend in a north-
easterly direction, at an angle of about 37° from high, down to low-
water mark, and, doubtless, to some distance below it, with the
stems of trees embedded at right angles to the plane of stratifica-
tion, having retained the original position in which they once grew,
and having subsequently been upheaved on the flanks of the granitic
nucleus of the island. As many as twelve or fourteen trunks have
been observed on different occasions and within a circumscribed area.
The stems of the trees are perfectly cylindrical, from 15 to 20 inches
in diameter, with their roots extending down into the subsoil—one
of them, a Sigillaria, must have been a hollow cylinder, through the
interior of which several vigorous young shoots had made their way
at the time it was suddenly buried by a shower of ash, Another tree
must have been perfectly hollow, filled up with débris of vegetables
and with fir cones. Mr. Binney, who has undertaken to make a
more minute examination of the plants, has found specimens of
Sigillaria, Lepidodendron, and a species as yet undescribed. The ash
itself is very much indurated, having, in fact, very much the ap-
pearance and hardness of ordinary trap rock. So far as known, the
O02 Bryce—Age of the Arran Granites.
trees referred to are the only instance of Carboniferous trees pre-
serving both their original outline and position and their internal
structure.
IV.—On tHe AcE or THe Arran Granites. By Dr. J. Brycs,
M.A., F.G.S.
HE author began by stating that all the extraordinary phenomena
of the geology of Arran arose from the abnormal position of the
Granitic nucleus of the north end of the island, which, instead of
forming an anticlinal axis, as is usually the case, had broken through
the slate band close to its outer edge, within a few yards of the Old
Red Sandstone. Within the area of this nucleus are two granites—a
fine and a coarse—and beyond the limits of the nucleus, two separate
granite tracts—both of the fine-grained variety—one at the outer
edge of the Old Red, and the other amid slates and limestones
abounding in fossils. The chief question of interest now in regard
to the geology of Arran lay in the age of these granites, and the re-
lative position of the two rocks forming the granite nucleus. Dr.
Bryce explained that Glen lorsa, instead of being occupied by the
fine variety, as was supposed, exhibits only the coarser kind, while
the fine granite occupies the heights on either side, and forms the
surface over all the higher interior parts of the nucleus; and, on the
south-east of the area, it runs out against the slate, into which it
sends veins in the same manner as the coarser kind does on the
flanks of Goatfell. He had come to the conclusion that this finer
variety was the later of the two, and overlaid the coarser kind,
while the two outlying granites of Ploverfield and Craigdhu were
of the same age as the fine variety of the nucleus. He adverted to
the singular fact that while granite fragments were absent from the
Arran conglomerate, small lumps of the Craigdhu granite had been
injected into the adjoining conglomerate—probably in a plastic state
—quite an exceptional case in the geology of Arran.
Professor Ramsay said that since he first knew the island of Arran,
his opinions regarding it, in some respects, had been considerably
altered. Since the publication of his book, now long out of print, some
things which were there stated in regard to the special Geological
features of certain parts of Arran, he certainly did not now consider
correct. If he were to write about the granite formation of Arran in
particular, there was scarcely a word in that book that he would re-
peat ; he would withdraw every word he had previously said. And
if he were now to express his opinion on the granite of Arran, he
believed he would be regarded as so heretical by Dr. Bryce and
others on the platform, that he thought, for the sake of the harmony
of the meeting, the less he said on the subject now the better.
Professor Ansted expressed his opinion that the granite deposits in
Arran were not erupted rocks, and said that the evidence in very
many cases of granites not having been erupted in the ordinary
sense of the word, was so great as to be entirely incontrovertible.
There was no such thing as eruptive granite, properly speaking.
Duke of Argyll—Trap and Granite of Mull. 008
Granite was originally a stratified rock, merely changed by intense
heat and pressure, and could not, therefore, be said to be eruptive in
the usual sense.
Mr. EH. A. Wiinsch said that he had accompanied Dr. Bryce in his
researches, but had arrived at very different conclusions. The posi-
tion maintained by Dr. Bryce that there were two granites of dif-
ferent ages—the fine grained erupted through the coarse grained—
was utterly untenable. All the granites of Arran he believed to be
of one age, and the difference in grain was merely owing to the dif-
ference in texture of the different strata previous to being metamor-
phosed into granite.
The President also expressed an opinion that granite is not erupted
rock in the ordinary sense of the term.
V.—On tHE TRAP AND GRANITE IN THE IstAND or Mutt. By
His Grace the Duke of Areytt, K.T., D.C.L., F.R.S.
EN CRAIG, one of the lower shoulders of Ben More, exhibits
very clearly the passage of a rock, which looks like pure trap
into regular granite. At the base of the shoulder of the mountain,
which may be about 2000 feet high, it is a mass of fine-erained com-
pact granite. At the top it is a mass of tuff which weathers white,
and has a fracture like some kinds of trap. At an immense eleva-
tion this tuff contains many crystals of felspar, very distinctly
separated. A little lower down these crystals become more frequent,
a granitic rock appears, and then comes the regular granite. His
Grace could detect no distinct separation. The top of the mountain
is very white, the rock very shattered, some of it very light, with one
or two dykes passing through this trap-like mass. The dykes are of
a closer texture, with white crystals unlike the surrounding mass.
The whole structure of Ben More, in Mull, is full of interest. The
summit peak is of stratified rock—mica slate—and all the lower
shoulders are granite, or igneous rock becoming granite.
VI.—On tHe Camprian Rocks or Lianperis. By Grorcr
Maw, F.L.S., F.G.S.
CUTTING on the branch railway from Carnarvon, now in course
of formation, has exposed the structure of the Lower Cambrian
beds, the most complicated part of the series. Underneath the beds
worked for slates in the Dinorwic and Glyn Quarries, there occurs a
considerable thickness of a trap-like rock, obscurely banded with
dark olive green and dull buff, which rests unconformably on the
upturned edges of a still more ancient slate rock. Many of the
dark-green bands, interstratified with the workable slates of the
higher series, and which have been grouped with the Cambrian grits
and pebble-beds, contain isolated fragments of altered slate, and
wherever they are in contact with the blue or purple slates, a thin
course of altered green slate occurs at the junction. Towards the
lower part of the upper series in the Glyn Quarries, the green
matter occurs as thin bands, in contact with which the slate has been
04 Maw—Cambrian Rocks of Lianberis.
altered to a pale green in the same way as that adjacent to the intrusive
dykes of greenstone. The dark green bands were found on analysis
to exhibit a totally different composition to that of the slaty matrix,
and appeared to have been derived from a different source. With
reference to the condition of fusion, under which the dykes of green-
stone were intruded, judging from the kind of alteration produced
in the adjacent slate, the heat could not have been sufficient to
effect a purely vitreous liquefaction of the traps; and experiments
proved that the slaty matrix was fusible at a temperature at which
the greenstone remained refractory.
VII.—On toe ALTERATION oF THE Coast Line or NorFoux.
By J. Wyatt, F.G.S.
HIS paper described the result of observation on the changing
coast line of Norfolk. The author showed that the geological
changes in this part of the island were not all to the loss of the
nation, proving that in West Norfolk there was a continual addition
to the area. A secondary object of the paper was to enforce the
necessity of accurate records of the changes of coast lines, and the
author suggested that this should be undertaken by a responsible
department of the Government, who should combine the two systems
adopted by the Ordnance and Admiralty Surveyors,
VIII.—Rerort on Drepcinc amMonG THE SHETLAND Istzs. By
J. Gwyn Jerrreys, F.R.S., F.L.S., F.G.S.
HIS, the fourth report by Mr. Jeffreys on dredging in the British
A seas, as usual contains observations of much interest. Five
species are added to the list of British Mollusca, namely, Terebra-
tella Spitzbergensis, Dav. ; Rhynchonella psittacea, Gm. ; Leda pernula,
Mill.; Siphonodentalium Lofotense, Sars.; and Cadulus subfusiformis,
Sars. ; and more information is gained on the geographical distribution
and habits of the Mollusca. A list of species obtained from a depth
of 170 fathoms is given, of which sixteen were living, and thirty-
eight dead. The shells were of the usual tints; the notion that
colour is absent, or fainter in shells from deep water appeared to be
quite unfounded. Relics of the Glacial epoch occurred in 170
fathoms, and higher, up to 80 fathoms; they were—Pecten Islandicus ;
Tellina calearia; Mya truncata, var. Uddevallensis; Saxicava rugosa,
var. Uddevallensis; Mélleria costulata; and Trochus cinereus.
In dredging at a depth of about eighty-five fathoms, on a soft, sandy
bottom, twenty-five miles north-north-west of Unst, the canine tooth
of an animal of the weasel tribe—probably a ferret—and the shoulder-
blade of a bat were brought up. The author is indebted to Mr.
Boyd Dawkins for an examination of these remains.
Reynaud.— History of Minerals. d00
REVIEWS.
J.—Histrorre ELEMENTAIRE DES Mineravx UsveEs par JEAN ReEy-
NAUD. 2me edition. 3 planches. 8vo. pp. 312. Paris: L.
Hachette & Cie. 1867.
HIS little book is one of the series called the “ Bibliothéque des
Mervielles.” It is quite an elementary treatise, as stated in
the title, on the common minerals, and has been written in the hope
of popularizing the study of mineralogy amongst those who have
not the leisure to penetrate deeply into the science, but desire to
know a little of what is daily going on around them. Being only
addressed to those who have no previous knowledge of the subject,
the author has, as far as practicable, avoided all technical language ;
nor does he enter into theories, only treating of the minerals gene-
rally met with in every-day life, and these more with regard to their
commercial uses than their physical laws.
With this object in view, he has divided all minerals into five
great classes, viz. :—les Pierres, les Terres, les Combustibles, Mine-
rais métalliques, et les Haux minérales. The substances comprised
in these divisions he has taken in the order of their relative import-
ance to man in the arts and manufactures, only describing those that
are at present useful, and passing over those whose interest is purely
scientific.
Hach division of the book is commenced with a short intro-
ductory chapter, the first of which, for instance, describes what is
usually understood by the word “rock,” gives an account of pierres
en general, of the principal elements of which the most abundant
rocks are composed. Next follow chapters on granite, including its
varieties, syenite, etc. on porphyry, limestones, sandstones, etc., at
the end of which are given short notices of the less important
siliceous, carbonaceous, and other minerals, such as lapis-lazuli,
malachite, or fluor, describing their appearance, composition, pro-
perties, uses, durability when used as building materials, localities,
method of working, and their histories, where they have been known
to, and used by the ancients. The last chapter of this division is
devoted to precious stones.
The second division, “les Terres,” comprises soils, brick-earths,
china-clay, etc.
“ Les Combustibles” are, of course, coal, peat, bitumen, and sulphur.
“Les Minerais métalliques”” describes the ores and other of the
principal metals, with the methods of reducing them.
The last division treats of “les Haux Minérales,’ and the sub-
stances held in solution by them.
Three chromo-lithographs accompany the text, and, considering
the price (1s. 8d.), we must not be too critical of the details.
This book being of so elementary a nature, we cannot expect it
to have many readers in this country, but we hope that it may havea
large circulation in France, for we feel sure that if any one reads it
through, they will be tempted to go more deeply into this interest-
ing study.
006 Geological Society of London.
2 POS ASIN) eee @ Carn Ses
es
GeroLocicaL Society or Lonpon.—The opening meeting of this
Society took place on November 6, 1867. Warington W. Smyth, Hsq.,
M.A., F.R.S., President, in the chair. The only communication read
was “On the Amiens Gravel,” by A. Tylor, Hsq., F.L.S., F.G.S.,
which, with the discussion which followed, occupied the entire even-
ing. The author referred first to the prevalent views respecting the
gravels of the Valley of the Somme, namely (1) that there are two
deposits of distinct age—the upper and the lower valley gravels ;
(2) that the former of these is the older; (3) that the Valley of the
Somme has been excavated to the depth of forty or fifty feet since its
deposition ; (4) that both gravels contain bones of extinct animals
and implements of human manufacture, the lower gravels, however,
containing the greater number of species of mollusca, and the upper
the greater number of flint implements; and (5) that the height
(70 feet) of the gravels at St. Acheul above the present level of the
Somme is much beyond the limit of floods, and that, therefore, they
could only have been deposited before the river-channel was cut
down to its present level. He then pointed out that the general
effect of these views is to refer back the remains of man found at
St. Acheul to an indefinite date separated from the historical period
by an interval during which the valley was excavated.
In former papers Mr. Tylor stated his belief that the upper and
lower valley-gravels of the Somme are continuous and of the same
age, which he considered to be close to the historical period. In
this paper he stated facts, which appeared to him to demonstrate the
truth of his views, and described a number of sections near Amiens,
in which the levels were laid down from an exhaustive survey by
M. Guillom, Chief Engineer of the Northern Railway of France.
The conclusions he had thus been able to arrive at are the
following :—(1) That the surface of the Chalk in the Valley of the
Somme had assumed its present form prior to the deposition of any
of the gravel or loess now to be seen there; (2) that the whole of
the Amiens valley gravel is of one formation, of similar mineral cha-
racter, contains nearly similar organic remains, and belongs to a date
not much antecedent to the historical period; (3) that the gravel in
the valley of the Somme at Amiens is partly composed of débris
brought down by the river Somme and by the two rivers the Celle
and Arve; and partly of material from the higher grounds washed
in by land-floods ; (4) that the Quarternary gravels of the Somme
are not separated into two divisions by an escarpment of Chalk
parallel to the river, as has been stated; (5) that the evidence of
river-floods extending to a height of at least 80 feet above the pre-
sent level of the Somme is perfectly proved by the gradual slope and
continuity of the gravels deposited by them; and (6) that many of
the Quarternary deposits in all countries, clearly posterior to the form-
ation of the valleys in which they lie, are of such great dimensions
and elevation that they indicate a pluvial period just as clearly as the
Geological Society of Glasgow. 007
Northern Drift indicates a Glacial. This Pluvial period must have
immediately preceded the true Historical period.
Gzotocicat Sociuty or Guascow.—1. The annual address in con-
nection with the opening of the winter session of this Society was
delivered on October 31st, 1867, by Professor John Young, M.D.,
F.R.S.E., the President. The subject he had chosen from his own
observations was ‘“‘The evidence of zoological continuity im the
past.” In speaking of the terms ‘high’ and ‘low’ as applied to
organisms—terms used too often very vaguely—the lecturer put
several cases. Amongst others, the comparison of the lamb and the
human infant immediately after birth, which shows a superiority on
the part of the former, and raises the question, as regards the inver-
tebrated animals, as to the period of life which supplies data for the
decision as to rank. In dealing with the origin of species and the
evidences of zoological continuity, Dr. Young stated that, from the
earliest times, there must always have been suitable localities for
some forms of life. The lecturer passed in review the fossils of the
Paleozoic and Triassic strata, and showed that, so far as the structure
of their hard parts is concerned, it cannot be affirmed as an absolute
truth in all cases—though there is great probability in some—that
there has been progress from the earlier to the more recent forms.
The fish and labyrinthodonts were the groups chiefly referred to,
and in these, especially in the former, it was pointed out that
structures once relied on as proof of embryonic condition had since
(as the heterocercal tail of fishes) proved to be the rule in many, if not
all, living genera. Dr. Young then described at some length the
structure of the amphibians, or frogs and salamanders, with their
allies, and indicated the points on which they resemble fish on the
one hand and reptiles on the other. The amphibians were selected
because the classification of the series shows a gradation of struc-
tures generally parallel to the development of the tadpole into the
frog. He then pointed out that the labyrinthodonts belonged to the
lower divisions of the amphibians, but that at their first appearance
in the Coal they present two forms of very unequal development as
regards their skeleton, just as at the present day amphibians co-exist
of all degrees of development. It was next shown that functionally
the sharks are, in many respects, better endowed than a large section
of the amphibians. The latter, however, are ranked higher than the
former. In the lower members, however, of a class there is no
degradation in the sense of backward progress, where structural
inferiority is found, it is an arrest of development; where the parts
are fewer, it is because the functions are more limited. There are but
two ways of the origin of living things; not speaking of the first
origin of all, but of the appearance of new forms in a series already
existing. The one of these ways is that of a relation by descent,
with modification ; the other is the organization of inert matter.
The one is within the limits of science, the other is wholly beyond
the pale. We must either believe in the hypothesis of special
creation, or in that of zoological continuity. The former involves
508 Geological Society of Glasgow.
so many contradictions, and is after all so utterly barren, that we
are compelled to seek for some theory which shall show that the
classification of animals depends on the right understanding of laws
continuously operative throughout all time. Descent, with modifi-
cation, is the probable origin of our present faunas, but that descent
must be compatible with the continuance, unaltered for a shorter or
longer period, of some at least of the plans of structure ; must have
been so far under external influences that the causes of change have
been at all times variable in amount and in extent of action; other-
wise, at present, we should see around us only the higher forms, the
lower having succumbed to a universal law of change. The spirit
of this view is contained in a pregnant sentence by one of our
highest authorities in Botany, who has contributed much by his
writings to the philosophic cultivation of Natural History. Dr.
Hooker, in his Flora of Tasmania, says “The degree or amount of
variation may be assumed as differently manifested at different
epochs in the history of the group,” and goes on, “as all the highest
orders of plants contain numerous species, and even genera, of as
simple construction as any of the lower orders are, it follows that
the physical superiority which is manifested in greater extent of
variation, in better securing a succession of race, in more rapid multi-
plication of individuals, and even in increase of bulk, is in some
cases of a higher order than that represented by mere complexity or
specialization of organ.”
2. An ordinary meeting of this Society was held on November 7th,
Professor Young, M.D., F.R.S.E., President, in the chair. The
following papers were then read :—
I. On the Order of Succession among the Silurian Rocks of Scot-
land. By Archd. Geikie, Hsq., F.R.S., Director of the Geological
Survey of Scotland. The Silurian rocks may be regarded as the
framework of the country. They spread over the Southern uplands,
and then, sinking under the central valley of the Lowlands, rise up
on the farther side in a metamorphosed form, and stretch far and
wide as the gneisses, schists, limestones, and quartz rocks of the
Highlands. It is, of course, in the unmetamorphosed or southern
belt that the order of succession among the Scottish Silurian rocks
must first be studied. The contortions in this southern belt obscure
the relations of the beds; but viewed on the great scale, a longitudi-
nal axis is seen to traverse the chain in a N.E. and §.W. direction,
crossing Annan valley, a little south of Beattock. This central
portion must therefore be of older date than those towards the mar-
gins where Upper Silurians are found on the north at Lesmahagow
and the Pentlands, on the south in Kirkeudbright. Pending the
detailed mapping of the country, the succession seems at present to
range from Llandeilo Flags, represented by the beds along the axis,
to the Lower Llandovery, to which certain Ayrshire beds seem to
belong. The hard grey grits, greywacke sometimes conglomeratic
or brecciated, blue, red, or olive shales, and occasional but inconstant
bands of limestone, which make up nearly the whole of the Southern
Geological Society of Glasgow. 559
Uplands, are, in default of more detailed paleontological data, most
safely referred to the Caradoc and Llandeilo rocks of Wales.
In the discussion which followed, Mr. E. Hull, F.R.S., drew at-
tention to the poverty of the Scottish Silurian rocks in Limestones,
as compared with those of the Border districts of England and
Wales, where calcareous strata are more fully developed, and re-
marked that there was an apparent similarity in the distribution of
calcareous strata of the Silurian and Carboniferous rocks of the two
countries. In the latter case, the Carboniferous limestone was most
fully developed in central England, attaining in Derbyshire a thick-
ness of over 4000 feet, and gradually thinning away northward into
central Scotland. On the other hand, the sedimentary materials
augment in bulk towards the north-west, and in north Lancashire
attain a thickness of about 18,000 feet. Mr. Hull thought it pro-
bable that the Silurian sedimentary strata would be found to aug-
ment in bulk in a northerly direction, and in the inverse ratio of the
calcareous beds of the same formation. He believed that the cause
in each case (Silurian and Carboniferous) was the same, and that
these changes might be explained on grounds which Bischof had
hinted at in his “‘Chemical Geology” —that the existence of sediment
in the ocean is inimical to the formation of limestones. Applying
this doctrine to the cases of the Silurian and Carboniferous forma-
tions, and supposing the source of the sedimentary materials to have
lain in the region of the North Atlantic (then a continent), the ex-
planation of the tailing out of the calcareous beds towards the north
and north-west might, he thought, be found.
IJ.—On the Upper Silurian Brachiopoda of the Pentland Hills,
and of Lesmahagow in Lanarkshire. By Thomas Davidson, Esq.,
F.R.S., etc. Mr. Geikie had determined that the Upper Silurians
form the fundamental rocks of the Pentland chain, and are covered
unconformably by the Old Red Sandstone, by felspathic traps of Old
Red age, and by lower Carboniferous sandstones ; while their geo-
logical position was equivalent to the Ludlow rocks of England.
After the examination, however, of several thousand specimens of
the fossils, Mr. Davidson was of opinion that both the Ludlow and
the underlying Wenlock rocks were represented in the Pentland
Hills. The specimens of Brachiopods occur principally in the con-
dition of external casts and internal impressions—the shell itself
being rarely preserved. ‘These observations were followed by a full
description of the species, about twenty-six in number. The re-
maining portion of Mr. Davidson’s paper consisted of a description
of two species of Brachiopoda, Lingula minima, Sowerby, and a
Rhynchonella, discovered by one of the members, Mr. Robert Slimon,
in the Upper Silurian rocks of Lesmahagow. It was of great im-
portance that the fossils from the lower Palzeozoic series of Scotland
should be correctly described and illustrated; and with a view
towards furthering that object, he had gladly acceded to the request
made him by the President and by some members of the Society
that he should prepare for the Paleontological Series of the Trans-
actions a series of descriptions and illustrations of our Scottish
Silurian Brachiopoda.
560 Norwich Geological Society.
Norwica Gronocican Socrery.—Monthly meeting, September 3rd
(continued). The Rev. J. Gunn, M.A., F.G.S., President, in the chair.
The President read a letter from Mr. Searles V. Wood, jun., having
reference to the so-called deposits of the old estuary of the Yare.
Mr. Wood said, “I have been induced to doubt whether the beds
described by Mr. Prestwich, as covering the London-clay in Sir E.
Lacon’s boring at Yarmouth, be what he calls them, viz., the deposits
of the old estuary of the Yare. There may be nothing in my
doubts, but I will explain them. The depth to which these deposits
descend is 171 feet, the upper fifty feet being, according to Mr.
Prestwich, blown sand. Now as the town of Yarmouth stands only
from ten to fifteen feet above the present level of the Yare, this depth
of 171 feet would, on Mr. Prestwich’s view, imply that the estuary of
that river was originally 284 fathoms below the town of Yarmouth,
and was completly silted up to the marsh level. Such a depth, how-
ever, I find to be three times the deepest point inside the sands
forming the Yarmouth Roads, and more than twice the average depth
of the North Sea, which only exceeds seventeen or eighteen fathoms
in a few deep places far out towards Holland. Moreover, it is double
the greatest and three times the average depth of the estuary of the
Thames, where tt is fifty miles across from Harwich to the North Foreland.
It exceeds the depth of the English Channel, between Sussex and
France, and only one narrow submarine channel in the Straits of
Dover equals it. Moreover, if the thickness of the Crag and Chilles-
ford beds on the east side of Norwich be added to the base of Corton
cliffs, it would only take off from this 171 feet, at the most,
21, leaving 150 feet to be added to the thickness of the London-
clay, which the boring showed to be 310 feet under the 171. This
would make the thickness 460 feet for the London-clay, or more
than its maximum known thickness in its thickest part, viz., South-
east Essex. Under these circumstances I cannot help having a
suspicion that the so-called estuary beds are the prolongation of the
Cromer beds, which, in the form we see them at Hasbro’, seems to
resemble the beds pierced in the 171 feet boring, or rather in the
lower part of that boring, say the lower 120 feet. If there be any-
thing in this, the only way to determine it would be to put down a
borer from the base of Corton cliff, and learn whether these beds
are present there below the red loam sand and Boulder-clay of that
cliff. Of course we can suppose the Yare estuary excavated to this
depth, with a proportional increase in the depth of the adjoining
North Sea; but when we recollect the rapid way the coast wastes, it
is difficult to suppose that the cliffs forming this estuary on either
side of the Yare, now represented by the hills north and south of
the river (which are only six miles separated), would not have been
wasted by the agency of deep waters of such an estuary during the
long period required for silting up 171 feet, so as to push them back
to a much greater width than they now possess. If the Yare has
thus been silted up, why have not the other rivers of the east coast ?”
The President said Mr. Prestwich came to the conclusion he did by
examining the shells; if he had seen the Tedlina obliqua, or any of
Norwich Geological Society. ob 1
the Norwich Crag shells, he would have known them instantly.
For his own part, he thought Mr. Wood’s difficulties were easily
answered. ‘The water-level was always permanent, that of the land
was not. The land was upheaved to a great extent, and then the valley
was scooped out, and subsequently going down again, was silted up.
Mr. Harmer said Mr. Wood’s difficulty was that a vast period of
time must have elapsed while the 170 feet was being silted up. The
President remarked that it must be considered they were speaking
of a time when rivers were stopped up with ice, and when tons of
materials were rapidly brought down the streams, much more rapidly
than now.
The President then read a report “On an Excursion to Corton
and Hopton.” The very contradictory opinions expressed in the
GrotocicaL Macazine respecting the number and position of the
Boulder-clays in Norfolk and Suffoll appear to render it desirable
that the geologists, who maintain such different views, should for a
time rest their pens and use their eyes. In accordance with this
impression, an excursion of the Norwich Geological Society was
fixed for September 19th, and the members met on the beach at
Corton, in Suffolk. It was very satisfactory on the day of excursion
to find the beach cleared of shingle, and the “red loam,” as Mr.
Wood calls it, exposed about two miles in extent. Six small boulders
of granite and trap-rock, besides flints, several of them polished and
scratched, were taken out of it. The bed varied in thickness from
four feet to twelve feet, and was at very different levels, sometimes
dipping below the beach, and in one instance, near Hopton, up-
heaved about ten feet. It is unstratified and, in the opinion of the
members present, corresponds with the Lower Boulder-clay at
Happisburgh in every respect except colour. The position is pre-
cisely the same between the laminated series and the Middle Drift.
The exteusive beds of gravel above may suggest the cause of this
change of colour.
On this excursion not only was this Boulder-clay seen to be exposed
at the base of the cliffs, but im many places four and five feet, and
in one place, where an upheaval had taken place, about fifteen feet
of the laminated series. The forest bed, also, was seen peeping out.
Besides the beds beneath the Lower Boulder-clay, the Middle and
the Upper Drift were seen to advantage, and large masses of septaria
in the Upper Boulder-clay. What was most unexpected was the
range and depth of the Post-glacial sands and gravels above the
Upper Drift, which promise the discovery of flint implements, and
other relics of the early occupation of man.
Geotocists’ Assoctation, Untverstry Coiurece, Lonpon.—The
session commenced on Friday, the 1st, with a paper by the Rev.
Thomas Wiltshire, M.A., F.G.8., “On the Chief Groups of the
Cephalopoda.” The author having given a definition of the forms of
life to which the term Cephalopoda is restricted, proceeded to divide
the class into the two great orders of the Dibranchiata and the Tetra-
branchiata : the common Cuttle-fish and the Pearly Nautilus being
VOL. IY.—NO, XLII 36
562 Bristol Naturalsts’ Society.
taken as types of these orders, various facts in connection with their
organization and habits were mentioned, and allusion was made to
some of the other genera now existing in the present seas. These
remarks served as an introduction to the description of the fossils be-
longing to the same class. The Belemnites, the Ammonites, and the
Nautili, with their sub-genera were explained. The old traditions
relative to the two former were not forgotten, and the knowledge of
more modern times brought to bear upon the subject. The paper
closed with some remarks upon the existence of the Nautili group in
the more ancient deposits, and upon the importance to be attached to
the zones of all these fossils in connection with agriculture and
mining operations.—Land and Water, November 9th, 1867.
Bristot Narurauists’ Socrmry.—At a meeting of this Society,
held on October 24th, Major Thomas Austin, F.G.S., in the Chair,
Mr. W. W. Stoddart, F.G.S., read a paper “On the Lias series of
Bristol.” In describing the Cotham Grove quarry, the author stated
that the beds attained a thickness of fourteen feet five inches, of
which about half belonged to the so-called “Sutton series.” This
series was placed by Mr. Tawney’ in the Rhoetic formations when he
first described the beds as developed at Bridgend, Glamorganshire ;
subsequently, Mr. Bristow? has referred them to the zone of Am-
monites planorbis in the Lower Lias, with the appellation of Lias
conglomerate, in explanation of their characteristic structure. This
section at Cotham decidedly proved the latter opinion to be correct,
as the fossils of the Planorbis zone were found both above and below
the horizon of the Sutton fossils. Details of the various strata were
given; the Sutton series comprised twelve beds of limestone,
separated by bands of clay containing encrinital joints. The sixth
bed from the top contained the most characteristic fossils in the
greatest numbers, namely, Lima Dunravenensis, L. gigantea, L. tuber-
culata, and Pecten Suttonensis ; Plicatula intusstriata, met with in the
series at Bridgend, was here absent. Underneath the Sutton series
were beds containing Ammonites Johnstoni, Pholidophorus, Modiola
minima, Myacites, Monotis, etc., and at the base the Cotham marble.
Mr. Stoddart added that Mr. Etheridge and Mr. W. Sanders were
satisfied of the correctness of his views.
PaLMoNTOGRAPHICAL Socrnry.—A general meeting of this society
was held on the 31st of October, when Dr. James Scott Bowerbank,
F.R.S., was unanimously elected President in the room of Mr.
Hamilton, deceased, who had filled the post of president for 20 years,
and Professor Phillips was chosen to fill the vice-presidentship,
vacated by Dr. Bowerbank. The election of Dr. Bowerbank to the
presidental chair of this society will be gratifying to every one who
knows how very much geological and paleontological science owe to
him. Many a man, now eminent in science, has been heard to at-
tribute his first feelings of interest in scientific pursuits to Dr.
1 Quart. Journ. Geol. Soe., vol. xxii. p. 69.
2 GEOLOGICAL MAGAzine, ante, p. 216,
Correspondence. - 563
Bowerbank’s patient and generous teaching, and his subsequent rise
to Dr. Bowerbank’s kind introductions and encouragement. The
society itself may be said to owe its formation to him, for when it
was proposed to figure the fossils of the London clay, he asked the
pertinent question, “‘ Why not figure the whole of the British fossils?”
The idea was seized and acted on, and the works which the Paleon-
tographical Society publish annually are sufficient proof of the value
of the suggestion.—Land and Water, November 9, 1867.
CORRESPONDENCE.
THE VALLEY OF THE OUSE AT BUCKINGHAM.
To the Editor of the GronogicaAL MaGazine.
Sir,—In a paper by Mr. Searles V. Wood, junr., in the last
number of the Quarterly Journal of the Geological Society, there is
dae following foot-note (p. 809) :—
“The section of the valley at Buckingham, given in the Memoir
of the Geological Survey at sheet 45, appears to me quite at variance
with the actual structure of it. So far from there being any evidence
of the existence of an actual valley in this part prior to the Glacial
period, the mode in which the valley of the Ouse is cut through
the Glacial-beds shows the valley to have been wholly formed since
the deposition of the Glacial-clay.”
Will you allow me to call attention to a few facts which seem to
have escaped Mr. Wood’s notice when he wrote the above ?
The section to which Mr. Wood alludes was drawn from the
following evidence :—First, a quarry on the Stony Stratford-road,
just outside Buckingham, on the eastern side of the valley, showed
the following section :—
Drift- gravel,
Cornbrash,
Great Oolite.
Secondly, a quarry behind Buckingham Workhouse, on the opposite
side of the valley, showed Drift-gravel resting directly on Great
Oolite, without any Cornbrash between. Thirdly, at the Buckingham
cemetery, a little further to the west, we have a section exactly like
the first, namely, Drift-gravel, resting on Cornbrash, with Great
Oolite below.
Now these three sections seem to me to show conclusively that,
before the deposition of the Drift-gravel, a valley must have run
between the first and third, at least, as deep as the thickness of the
Cornbrash. I believe the central quarry showed that the hollow
had also cut down into the Great Oolite; but I have not my note-
book now with me, and cannot speak certainly on this point from
memory. ‘These little points of evidence are so minute that no one
can be blamed for overlooking them; but even if they had not been
forthcoming, I do not think Mr. Wood’s reasoning very convincing,
when he argues that, because the river has cut a valley through the
Glacial-beds, therefore there could have been no valley there before.
564 Correspondence.
Errors of omission are pardonable enough, but such a bit of logic as
this he must allow me to cry out against.
I add a sketch section, which will perhaps make my meaning
clearer.
SECTION ACROSS THE VALLEY OF THE OUsE, AT BuckINGHAM.
Ws.w. ¢ b a E.N.E.
1 Drift Gravel. @ Quarry on Stony Stratford Road.
2 Cornbrash. b 6 Quarry bebind Workhouse.
3 Great Oolite. ec Cemetery.
Dotted line—supposed outline of surface before the deposition of the Drift Gravel.
Yours obediently,
A. H. Gren.
Monx Brerron, BARNSLEY,
Nov. 18th, 1867.
AGE OF THE THAMES VALLEY DEPOSITS.
To the Editor of the GrotocicaAL MAGAZINE.
Srr,—Mr. Searles Wood, jun., in his essay on the structure of the
Post-glacial deposits of the south-east of England, published in the
last Quarterly Journal of the Geological Society, Vol. xxiii. p. 394,
has made some remarks relative to a paper of mine, on the Lower
Brick-earths of the Thames Valley, which ought not to pass without
notice. Into the merits of his arc-theory, in explanation of the in-
equalities of the present surface of the ground, I do not intend to
enter, nor into the question of the supposed existence of the faults
in certain gravels and brick-earths. What immediately concerns me,
is the assertion that the Thames gravel, x 4 of section twelve, of his
essay, p- 409, overlies the mammaliferous brick-earths of Stonehams
pit near Crayford, and his inference therefrom that there is no
parallel between the brick-earths of Grays and those of the great
pit near Crayford, which was stated to exist in my essay. In
coming to my conclusion, so far from neglecting the evidence of
super-position, I have gone over the ground repeatedly with Dr.
Spurrell and Mr. Flaxman Spurrell, who have obtained a mag-
nificent collection of mammals from it, and know it better than
perhaps anyone else; and I have failed to detect the slightest proof
of the Thames gravel in question actually overlying the brick-earth.
Professor Morris also is fully pursuaded of the exact parallelism in
in point of time between the brick-earth at Crayford and that at
Gray’s Thurrock. I see therefore no reason for modifymg my
belief on that point. Mr. Wood assumes that the deposit on the
south of Dartford Heath, and at Hill House, is of the same age as
the fossiliferous: beds at Crayford; but he adduces no proof of it
whatever. Whether they be or not is perhaps an open question, but
the fact that the brick-earths in the railway-cutting, immediately to
the north of Mile End Terrace, and not more than half a mile from
Correspondence. 565
Hill House, contain nearly all the testacea now living in our rivers,
and none of those extinct in Britain, and no bones of mammals,
proves them to be much newer than the neighbouring deposits con-
taining older forms of life.
Again, the principal object of the essay seems to be to demonstrate
the Post-glacial age of the valleys in the south-east of Hngland,
and especially that of the Thames. That demonstration has al-
together eluded my grasp. An appeal to the author’s elaborate
maps, in the rooms of the Geological Society, supplies proof that
is directly subversive of his theory, The whole question lies in
a nutshell. Do you, or do you not, find Boulder-clay in the basins
drained by the rivers of which he writes? Is it present in those of
the Roding and Blackwater? A glance at Mr. Wood’s map of the
area drained by the former, shows that he recognizes that it is so
found. In reference to the latter river I have to correct a mistake.
Mr. Wood wrote to me for proof of its occurrence in the basin of
Blackwater ; and, unfortunately, without dreaming that my hurried
note would be quoted in print, instead of referrmg to my note book,
I ran my finger up an affluent of the Blackwater, imstead of the
main stream, and wrote Ingatestone and Mountnessing,—a mistake
that Mr. Wood has italicised and noted with a mark of admiration.
I ought to have written Witham Station. So far, indeed, as Mr.
Wood’s maps go, the Boulder-clay occupies any level, irrespective
of inequality of surface, and therefore they prove that the hill and
valley system “was sketched out” before the deposit of the over-
lyimg Boulder-clay. Of course, in many places, the Boulder-clay
has been denuded by the present streams, and areas of London clay,
of variable extent, have been exposed. If Mr. Wood restricts the
term valley to the hollow in the immediate vicinity of a stream,
and does not mean the area below a line drawn from one water-
shed to another, he is merely disputing about terms. If the
excavation of the Thames Valley, using the term in the latter sense,
took place in Post-glacial times, the deposits contained in it must also
be Post-glacial, and the evidence of fossils characteristic of Pliocene
mammals in France and Italy, is useless in classification. To say
the least, no evidence has yet been adduced in support of this
hypothesis, that is based merely on a belief that the entire valley-
system of the South-Hast of England originated in centres of arc-like
or curvilinear disturbance.” W. Boyp Dawxtns.
lltx NovemsBer, 1867.
DR. A. VON KOENEN, ON THE BELGIAN TERTIARIES.
To the Editor of the GroLocioaL MaGazine.
Str,—In the November number of the Gronocrcan Magazine, M.
von Koenen, in dissenting from my way of viewing the Belgian and
East Anglian Kainozoic formations, represents me in a manner to
which I may reasonably object. My paper having been published in
the Journal of the Geological Society I should be sorry should its
members be misled.
066 Correspondence.
M. von Koenen starts with what is calculated to produce an
erroneous impression. At page 504 he says, ‘“‘ Mr. G. A. has published
a number of observations made at Antwerp during his short stay.” Of
himself he says, by way of contrast, ‘I have visited Antwerp on five
separate occasions, in three different years ;” but had he read my paper
with more attention than he has, he would have seen that I had been
there repeatedly ; and what is more to the point, that I had seen
the sections at Edeghem in 1861 (p. 284), when the extent of open
work was much more favourable for geological observations than
in 1865.
He complains (p. 505) that I do not follow the divisions of any
of the authors who have described those beds ; if this means that I
have not used such terms as Oligocene, Miocene (Grou. Mag., p. 507),
it is true, but it was not from ignorance ; rather from an old conviction
that such a system of nomenclature was based in vague, mistaken,
and theoretical views. He is incorrect, however, when he states
that I have disregarded old names. I took, what I still consider to
be, the natural division of the Belgic Kainozoic beds—that of M.
Dumont and M. Nyst. The natural system in geology and palzon-
tology is that which describes old sea-beds and their contents,
according to the guidance which the naturalist and hydrographer
have derived from the dredge and sounding lead; in place of this,
the artificial systematists have endeavoured to set up what are
merely convenient Museum arrangements.
Some of M. V. Koenen’s sentences are contradictions rather than
objections, p. 505, “ Barton Clay does not correspond in age with
Rupel Clay.” Waiting for better evidence to the contrary, it seems to
me that the approximation of the purely marine clays of Rupelmonde
to those of Barton is closer than that which can be established be-
tween any two deep sea mud-beds of the English and Belgic Num-
mulitic formations. It may be, and must be, that a freshwater
formation in one place is the equivalent of a purely deep-sea series
in another, the Physical Geologist may some day arrive at their
arrangements, but not so the Cabinet Conchologist. Another short
phrase used by M. Von Koenen at p. 505, is also calculated to mis-
lead : ‘‘ The Tertiary beds of Cassel, Luithorst, Freden, and Diekholz,
which he puts into the upper Kaniozoic, are..... coeval with the
Grafenberg and Sternberg Sandstones which he puts into the
Tonegrien.” Put in this way, it certainly represents me as writing
nonsense, but I wrote nothing of the kind. The reference given is
to a note, in which I state “that the map of the Crag Sea has been
drawn so as to include the Upper Kainozoic formation near Cassel,
ete.” There is an extension of sea-bed thus far into Hesse with the
following fauna :—
Solen ensis, Mactra triangula, Corbula nucleus, C. revoluta, C. cus-
pidata, Tellina distorta, Astarte incrassata, Cyprina Islandica, Venus
plicata? Cardiwn papillosum, Isocardia cor, Arca diluvii, A. noe,
Nucula sulcata, N. margaritacea, N. minuta, Coulyptrcea vulgaris, Bulla
utricula, B. ovulata, B. liqnaria, B. Lajonkaireana, B. acuminata,
EKulima subulata, H. nitida, Natica castanea, Turritélla communis, T.
Correspondence. 567
carinifera, Siliquaria anguina, Cerithium vulgatum, Lima perversum,
L. trilineatum, Buccinum macula, Pleurotoma rugulosum, Mitra eburnea,
M. plicatula, Dentalium strangulatum.
There is a sufficiency of Lusitanian features in this assemblage
to make it referable to that older condition of the North Sea known
as the Crag Period ; instead of associating such a fauna with that of
Sternberg ‘and Grafenberg, one object of my paper was to show that
there was no blending.
The mystification as to Cassel arises from the same cause as it did
at the Bolderberg; there is an admixture of fossils, but it is purely
accidental, owing to the lowest beds of one series (Kainozoic) having
been superimposed upon the uppermost beds of another (Tongrien).
This last has not been misunderstood by M. D’Orbigny (see Von
Koenen, p. 505), in whose geological scheme it is the latest and
uppermost marine assemblage of the great Nummulitic Period, and of
its Germanic sea area.
M. D’Orbigny’s only misconception consists in his placing his
“'Tongrien ” as a “sous-étage”’ of the *Falunien.” Into this he
was misled by the German authors. It is an error which may be
turned to good account by others, as showing how unsafe it is to
methodise from a bag of fossils gathered from the remanié beds of
one locality. Yours truly,
Rosert Gopwin-AvustEn.
CuitwortH Manor, GuILpForD,
November 19th, 1867.
MR. WHITAKER ON “SUBAERIAL DENUDATION.”
To the Editor of the GnotocicaL Macazinn.
Dear Sir.—I most unwillingly request of you to allow me space
to reply to some observations of my colleague, Mr. Whitaker, con-
tained in his paper “On Subaérial Denudation,” published in the
number for October last; and calculated to convey a very erroneous
impression of my views on this subject. Owing to a variety of cir-
cumstances, I had not read this paper, nor was I aware that any
personal allusion to myself was contained therein, until a friend
called my attention to the passage a few days since. In that passage
I find myself represented (p. 453) as “a strong believer in the sea, and
nothing but the sea,” as objecting to reasoning on logical principles, and
the writer concludes with the following :—-“‘ One should not be sur-
prised at the advocates of the marine formation of valleys and escarp-
ments looking down on logic, and scorning syllogisms,
unless they follow and overcome those prejudices which contracted
views of nature and magnified opinions of the experience of man
may have begotten,” ete. What may be the meaning of “following”
and “‘ overcoming” a prejudice, is a question which may well be left
to those who alone are conversant with logical reasoning.
If my critic had only taken the trouble to refer to my paper in
the GrotoeicaL Magazine (Vol. III, p. 474) on “The Denudation
of the Valleys of Lancashire,” and to another paper to which refer-
568 Correspondence.
ence is there made in the Popular Science Review (for October, 1866),
which he was bound to do before he undertook to give an exposition
of my opinions, he would scarcely have represented me as being
“a believer in the sea, and nothing but the sea” as an agent of denu-
dation. So far from this being the fact, I state in the former paper,
’ with regard to the scooping out of the valleys of the Lancashire
Hills, that they have been formed by rivers “in the great majority
of instances” (page 474), and again (in page 477), I add, “the
more I consider this subject, the more I am satisfied, that in the
great majority of instances in this region, the extent and limits of
river action are capable of the clearest demonstration. Most of the
valleys are really double valleys, the smaller being alone due to
river denudation,” and the evidence of this lies in the fact—that the
larger, or primary, valleys are filled with terraces of Marine Boulder- ,
clay, and are really plains of marine denudation in their earlier
stages.
In the paper in the Popular Science Review, I adopt a two-fold
view of denudation, under the heads of ‘“‘ Vertical Denudation,” and
“ Horizontal Denudation ;” the former term including the formation
of “channels and furrows, either branching or lying along parallel
lines, as in the case of mountain chains,” by the action of frost, rains,
rivers, and glaciers. Under the term “horizontal” denudation, I
include the formation of plains and terraces by wave action, either
of the sea, or large lakes.
If my critic had glanced at the same paper he would also have
seen that I adopt, though with some hesitation, the views of Professor
Ramsay, Dr. Foster, and Mr. Topley, regarding the subaérial denu-
dation of the Weald; and, without any hesitation, those of Mr. P.
Scrope regarding the formation of valleys and escarpments in the
region of Auvergne; and after this statement I am quite ready to
leave it to the judgment of your readers whether or not I am to be
regarded as “‘a believer in the sea and nothing but the sea.”
A believer in the sea I certainly am; both in its power of forming
valleys and escarpments, and this from the evidence of my own eyes.
I have seen along the coast of Cantyre, channels several hundred
feet in length, with steep walls scooped out of tough gneissose rock
by wave action, and caves hollowed out of porphyry and other
rocks, like part of a railway tunnel, many yards in length, and I
care for no @ priort arguments which are intended to prove that after
such exhibition of the power of wave action to cut narrow channels
in the rock, the formation of valleys by such an agent is an impos-
sibility. Knowing the variety of agencies which nature employs in
the formation of the features of the earth’s surface, and believing
that each special district requires the application of special principles,
I altogether repudiate as of universal application some of the general
axioms laid down by Mr. Whitaker with such show of authority ;
knowing from my own experience that some of them are contrary
to fact. I shall just remark on one or two of them here. He says:
(1) “Escarpments always run along the strike, whilst sea-clifts
rarely do 50.” The “rarely” is a saving clause, as there are many
Correspondence. 569
examples; but has it not occurred to the author, that towards the
close of the Drift period, most of the principal escarpments of the
centre and north of England which run along the strike, must have
been sea cliffs when the land was from 200 to 400 feet lower than
it is.
(4) “If escarpments have been formed by the sea, there ought to
be at their foot some resultant, a beach or other marine deposit; but
this is not the case (except where masses of Boulder Drift end near
the bottom of a ridge),” etc. To this I reply that these “‘ masses of
Boulder Drift” are very often level terraces of marine origin, and to
all intents and purposes sea-beaches, or beds; but besides this, there
are true sea-beaches at the foot of escarpments, as for example, in
the Vale of Gloucester, at the foot of the Cotswold Hills.
I would also remark, that it is surprising to me, how any one who
believes in the formation of Professor Ramsay’s ‘“‘ Planes of Marine
Denudation,”’ can question the power of the sea to produce escarp-
ments, aS some escarpments are only the lines along which the sea
left off its work in the formation of such planes.
In conclusion, I will only express a very strong conviction that
we shall never arrive at true views of the operation of nature in
sculpturing the surface of the earth, unless we take into considera-
the effects of all possible agencies, and give them their due place in
the great work. I remain, yours truly, Hpwarp Hutt.
38, Haminton Park TERRACE,
Guascow, 18 Nov., 1867.
ON CLIFFS AND ESCARPMENTS.
To the Editor of the GrotoaicaL MaGazine.
Str,—I know very little about escarpments in the soft newer
formations, but as I have seen a fine cliff cut by the Atlantic in the
hard, older rocks that occur in the west of Ireland, and also in the
Boulder-drift, perhaps I may be allowed to make a few remarks on
Mr. Whitaker’s notes on cliffs in his “Comparative table of the
distinctive features of Escarpments and Cliffs.” !
“CLIFFS.”
(a) “Rarely run along the strike,”
but at all angles to it, and cut through
many formations in succession.”
1 Grout Mac. November, 1667.
REMARKS.
(a) It rarely happens that a sea-cliff
can keep to the out-crop of a bed, for it
is highly probable that the beds were not
raised to their present position horizon-
tally. However, it does occur sometimes,
although the beds may not be per-
fectly horizontal; as, for instance, on the
westerly coast of Aranmore, Galway Bay,
where a bed of shale for miles forms the
base of a perpendicular cliff: also on the
coast of Clare, where a thin bed of lime-
stone in the Coal-measure shales acts in
a similar way. At the base of a drift-
cliff, there is often a bed of stiff clay;
just as it will often occur at the base of
a drift-cliff formed by a stream.
Vol. IV. p. 491.
2 Ought not this to be out-crop, or basement ?
570
“CLIFFS.”
(4) *‘ Tops mostly very uneven.”
(c) ‘‘ Rarely through the highest
ground of a country, but mostly backed
by higher ground.”
«¢ HSCARPMENTS. ”
(d) “ Very rarely have the sea at their
foot, but often springs and watercourses.”
(e) ‘“ Often run in more or less winding
lines.”’
“CLIFFS.”
(f) “Mostly a beach at their foot.”
(A) ‘ Bases at the sea-level.”
From the above remarks may
Correspondence.
REMARKS,
(4) In the west of Ireland the tops of
the escarpments are also ‘‘ mostly very
uneven,’ except, perhaps, some of those
limestone escarpments in the Barony of
Burren, Co. Clare; but these are very
similar to the cliffs now being formed by
the sea in the limestones along that
coast,
(c) If (for argument sake) we allow
that ail cliffs were formed by the sea, it
would be nearly impossible that the
present sea-cliffs should run through the
highest ground of the country. For if
the land rose gradually the sea-action
would form a slope, a period of rest
being necessary for the formation of
cliffs; and, therefore, to allow of the
cliff being in the highest ground, each
succeeding rest must, at least, be of
twice the duration of the previous one.
However, in spite of these conditions,
many of the headlands extending into
the Atlantic slope from the cliff inland.
(d) Most, if not all, of the drift-sea-
cliffs have springs at their base; so have
the previously mentioned cliffs in Aran-
more and Co. Clare. There are, also,
usually springs at the base of a cliff which
rise from a horizontal, or nearly hori-
zontal, master-joint.
(e) The sea-cliffs on the west of Ire-
land are very irregular, never in anything
approaching a straight line or a wide curve.
(f) On the west of Ireland there is
rarely a beach at the base of a cliff,
except, perhaps, when it is of Boulder-
drift, and even then not always.
(h) Not always. If there is a hori-
zontal, or nearly horizontal master-joint,
either above or below the sea-level, the
cliff is nearly sure to spring from it; or
it may spring from a soft bed that occurs
under similar conditions.
it not be suggested that sound
conclusions cannot be drawn from observations made only among
peculiar rocks.
If an observer will compare the work done by the
two dissimilar forces—marine and subaérial (including ice) denu-
dations—he will be surprised to find the results so very similar in
appearance.
However, he should always bear in mind that the
subaérial agencies may work alone, when the marine agencies must
always be helped from above.
ConnEMARA, Nov. 10th, 1867.
Yours, etc.,
G. H. Krvanan.
N
Correspondence. O71
LYELL, JUKES, AND WHITAKER ON SURFACE-GEOLOGY.
To the Editor of the Gro~ocicaL MaGazIne.
Srr,—Since I last wrote very briefly on the origin of escarpments,"
you have admitted into your pages two articles, one by Mr. Whitaker,
and one from Professor Jukes, which, were they to remain unnoticed,
might leave the controversy too one-sided, more especially as the
first-named author has spoken in very strong and persuasive terms
(coupled with a grace and elegance which remind one of the illus-
trious Playfair), which are calculated to mislead those who have not
studied the other side of the question.
Lyell’s Recantation.—Let me first call attention to a change of
opinion in the great founder of inductive geology—Sir Charles Lyell,
as announced by Mr. Whitaker. Ordinary coast-action, Sir Charles
now believes, will not account for the parallelism of the Chalk and
Greensand escarpments, or for both following the strike of the strata.
But to reject coast-action as the main or primary cause of these
escarpments is not entirely to give up the marine theory ; for they
may have originated in longitudinal cracks during axial elevation,
and may afterwards have been deepened and widened, and their
inner sides planed down by currents maintaining a general uniformity
of direction, but at intervals deflected and reflected so as to hollow
out the curvilinear ‘“‘coves” by which the “capes” are separated.?
But suppose it could be shown that powerful currents, operating at
a considerable, not “too great” a depth, are incapable of scooping
out the depressions bounded by escarpments, it would not be more
inconsistent with uniformity to suppose a cyclically-recurring in-
tensification of the action of currents, caused by sudden upheavals of
strata, than to admit ‘occasional strides, constituting breaks in the
otherwise continuous series of (organic) changes.” *
Whitaker on Chalk Escarpments—Mr. Whitaker and other sub-
aérial geologists, though they have thrown difficulties in the way of
the marine theory, have brought forward very few facts in support of
their own views. The main force of what they have advanced lies
in a few words—Because sea-coast action could not have done it,
therefore it has been done by rain and frost. To state that a river
sometimes flows near the base of an escarpment, coupled with the
admission made by Messrs. Foster and Topley, and implied by Mr.
Whitaker, that escarpments are not river-cliffs—that springs are
often found at the base of escarpments—and that time will accom-
plish anything . . . cannot be regarded as evidences, unless it can
be shown that these agents are now actually giving rise to phenomena
similar to those requiring explanation. An escarpment is a steep,
continuous slope. Continuity, both longitudinally and transversely,
are its essential characteristics. Springs, at intervals, cause landslips
which break this continuity, and therefore tend to destroy escarp-
ments. Rain-streamlets (where they are not prevented by a covering
1 Grou. Maa. May, 1867. d
2 See reference to escarpments under the Atlantic, td2d. p. 236,
8 Lyell’s Antiquity of Man,
572 Correspondence.
of turf) furrow their faces, and tend to disfigure a smooth slope by
a series of unsightly gutters. Frost cannot act effectively where an
escarpment or slope does not already exist. Mr. Whitaker, to a
certain extent, seems to admit this, when he speaks of “ outliers”
as “relics” of a former escarpment, and “inliers” as signs of a
future escarpment. He invests subaérial agency with a power of
beginning, by making something very unlike an escarpment, and
ending by ruining an escarpment—the escarpment being only a
stage of maximum development. Somewhat like Professor Babbage
and his calculating engine, he makes his machinery capable of
performing a miracle at a certain stage of its working, so as to give
a result the opposite of that preceding and following. ‘The fact
would appear to be, that the action of the atmosphere, instead of
forming a slope, tends directly to make a pre-existing slope less
escarpmental. It has never been satisfactorily shown how, on a
plane of marine denudation, the atmosphere could begin the work of
escarpment-making.
Removal of Detritus—Mr. Whitaker admits the absence of a talus
from the face of Chalk escarpments, and states that the solid chalk
comes up to the surface. But this is the case, not only with the
slopes but with the base of many Chalk escarpments; and it may be
asked, if rain has washed away the soluble chalk, what has become
of the insoluble flints? Is it reasonable to suppose that rain and
frost, which act intermittingly, or by successive stages, can leave no
sign of their action? Col. Greenwood (the father of modern sub-
aérialism) admits that one rain leaves soil on its path to wait for the
“next rain.” The entire absence of detritus implies a cause equal
in force and volume to a “‘ sweeping” removal of the mass of chalk
necessary to leave an escarpment. Uniformly-cut, and cleanly swept
surfaces of chalk are common not only on the face and at the base
of escarpments, but on the sides of gently swelling eminences, and
on the level summits of table-lands, or “planes of marie denu-
dation.” There are many short Chalk escarpments, and parts of
long escarpments, where the ground at the base is a plain, and
where there is no stream to carry away the detritus which must
result from the action of rain and frost, if they act at all. The
streams in the neighbourhood of other escarpments are so sluggish,
and choked with vegetation, that they tend rather to raise than
lower the level of the area through which they flow. Mr. Whitaker
admits that the formation of some escarpments is “ delayed,” and
that rains, during a “‘ former order of things,” must have been more
powerful than now. Why, then, not allow the advocate of marine
denudation to suppose the action of currents formerly more energetic
than at present? He appeals to the destruction of forests and other
changes introduced by man as diminishing the fall of rain; but it
is obvious that the denuding action of rain is much increased by the
removal of trees,! and the cultivation of the soil.
Inclined Escarpments.—Mr. Whitaker refers to escarpments, the
base of which at one place is higher than the top at another; but
1 See Lyell on North American forests.
q
d
>
,
%
Correspondence. O73
such cannot be escarpments running along the strike in the same set
of beds (according to Mr. Topley they cannot be escarpments at all),
and if not due to the sea they cannot be the effect of atmospheric
action—which “always follows the strike.” Escarpments consisting
of different beds at the lower from those at the upper end, can easily
be explained by supposing the sea to have acted at different levels.
A longitudinally-sloping cliff, of the same kind of rock throughout,
might have been left by the sea during a gradual rise of the land,
or it may have been unequally elevated after its formation. Sub-
aérialists are not consistent in calling the latter supposition “ground-
less and unwarrantable,” seemg that their theory (as explained by
Messrs. Foster and Topley) involves a successive tilting up of the
inner end of a valley to give “ excavating power ”’ to its stream.
Relation between Escarpments and Plains.—In the case of many
Tertiary, Chalk, and Oolitic escarpments in Hampshire (especially
in the vicinity of Southampton, where the parental relation between
escarpments now formed by the sea, and inland escarpments on the
same horizon, or at different parallel levels, is indisputable), Wilt-
shire, and Somersetshire, the top and base are continuous parallel
planes. The level areas above and below will be admitted to be the
work of the sea, and unless we can conceive of a coasiless ocean, it
is difficult to resist the belief that the face of the escarpment is
likewise of marine origin. That the areas at the base of escarpments
should be slightly inclined affords no presumption against the marine
’ theory, as this is often the case with table-land “planes of marine
denudation.” 3
Weathered Escarpments.—Mr. Whitaker speaks of “a_ sea-cliff,
weathered down into a slope with a talus,” as distinct from an escarp-
ment; but if the talus be a proof of the marine origin of a cliff,
the escarpments of the Oolite, Lias, and all the older rocks must
have been sea-cliffs. A striking instance is furnished by the
Cotswold escarpment, especially near Cheltenham and Gloucester,
where a rocky cliff is for great distances concealed under a sloping
talus, and where the atmosphere is still destroying a smoothly-
grooved (especially near Crickley) and pitted sea-wall, which, at
intervals, has resisted its action. The rocky limestone and mill-
_ stone-grit escarpments of Derbyshire, Yorkshire and other counties,
have their bases buried in accumulations of blocks, fragments, and
rubbish (where they have not at intervals been Swept clean, leaving
a grassy platform or slope), which rains do very little to remove.
The size of the fragments we see at the base of these cliffs (many
of which are in situations where they could never have fallen) must
be regarded as representing the size of the fragments which have
been carried away, and indicating the power (nothing short of
stormy waves) by which the transportation was effected. The go-
called rain-wash, in many cases, must have come from a distance,
and has not been furnished by a pluvial disintegration of the frag-
ments on the spot, as is evident from its composition.
Assumed Distinctions between Escarpments and Sea-clifis.—Mr.
Whitaker institutes a series of distinctions between escarpments and
574 Correspondence.
sea-cliffs, most of which do not apply to the escarpments with which
I am acquainted. I have only space for a few counter-statements.
1. The bottom of an escarpment does often keep to one level, and the top is
often uneven.
2. Sea-cliffs do not always run straight through homogeneous rocks, but very often
wind about in a succession of small capes and coves, which are included in ‘curves
of large radius.”
3. Among Archipelagos, such as the South of England must once have been, coasts
are as often deachless as are the foot of escarpments. Shores suddenly sloping into
deep seas, at a stationary level, or any kind of shores continuously rising, could never
become covered with rounded shingle.
4. Sea-cliffs are not ‘‘ backed by higher ground” in many parts of Archipelagos,
Escarpments are often backed by higher ground.
Destruction of Sea-cliffs—What Mr. Whitaker says about the
atmosphere assisting the sea reads like special pleading for a
favourite agent. It is as obvious that the sea makes its cliffs as it is
that without the sea there would be no cliffs. At least two-thirds
of the downfalling is the result of sheer gravitation through under-
mining. Many sea-cliffs for ages stand at the angle of gravitational
repose. But as Mr. Whitaker admits that an immensely greater
quantity of rock is denuded by the sea than by the atmosphere, it is
not necessary that the relative claims of “the organ and the blower”
should in this case be applied. The fact that the atmosphere does
wear down and destroy sea-cliffs does not, however, seem quite
compatible with the theory which assigns to the atmosphere a power
of forming cliffs or escarpments.
Preservation of Ice-marks.—Mr. Whitaker attributes a deficiency
of reasoning power to his opponents, while he himself uses one
kind of reasoning in speaking of the sea, and another in reference
to the atmosphere. If the preservation of glacial strie under the
sea, in some parts of the fjords of Norway, be an evidence against
sea-action, their perpetuation on rock surfaces under the air must
afford an equal proof of the inefficiency of rain. As regards the
latter, it should be remembered that they often extend over great
areas under a covering of soil, which could not be the case if “soil
is rotted subsoil” (as Col. Greenwood calls it) on its way to a lower
level.
Professor Jukes on the Avon Gorge.—In your Macazine (Oct., 1867,)
this able geologist applies the “hard gorge and soft valley,” theory
of Col. Greenwood, to the neighbourhood of Bristol. But from his
explanation, it is obvious that the theory requires the assistance of a
sliding scale to make it fit different localities. Besides the Clifton
gorge and the Bristol basin, there are at least ten hard gorges leading
out of soft valleys (some of them perfectly flat-bottomed plains,
with level-based escarpments, for instance, near Keynsham), which,
from the relative nature of the rocks in which they occur, would
appear to be inexplicable on the above theory. It may likewise be
asked, if the limestone on both sides of the Clifton gorge escaped
pluvial disintegration through being covered with newer rocks, how
were the limestone ridges of the Western Mendips preserved, in
Palozoic times, when the Old Red Sandstone was in course of being
Correspondence. 575
eaten away so as to form the Vale of Winscombe? Professor
Jukes implies that the sea, during the Glacial submergence, did no
more to make valleys than a canal is made by the water it contains.
I think the contrary can be shown by three facts: 1. The rate at
which the sea wears back its cliffs in many parts of the Bristol
Channel may be fairly stated as, at least, a foot ina year. 2. The
accumulations of drift in the midland and other counties (which
exhibit no trace of being re-arranged Tertiary gravels, and which
are only a part of what must have been excavated and removed to
a distance,) would be sufficient to fill up many valleys, and obliterate
many escarpments. 3. The duration of the glacial submergence
may have been at least 50,000 years, probably much longer.
During this period the sea must have converted many ~ shaped
vales into _1 shaped plains, and may have eaten back many miles
of the eastern side of the Severn valley so as to leave the great
Cotswold escarpment.
D. Macxrntosa.
P.S.—I see that the number of the Quart. Journ. Geol. Soc. for
the present month (Nov.) contains several important articles in
favour of marine denudation.
RESEARCHES IN BRITISH MINERALOGY.
To the Editor of the GrotogicaL MaGazine.
Sir,—Mr. David Forbes in a paper in the November number of
the London and Edinburgh Philosophical Magazine, under the title of
‘«< Researches in British Mineralogy,” gives the results of an analysis
made by himself of a silver-fahlerz from the Fox-dale silver-lead
mine, in the Isle of Man, and in the introductory paragraph he says,
“ Although the cupriferous tetrahedrite (occasionally containing
traces of silver) has been found in small quantities at various locali-
ties in both England, Scotland, Ireland, and Wales, there is no
analysis of true silver-fahlerz or polytelite, or even occurrence of
the mineral itself recorded, as far as the author has been enabled to
ascertain.” From this I infer that Mr. Forbes will be surprised to
learn that silver-fahlerz has already been found in quantity in this
country and mined for the silver it contains. For several years
past it has been raised and sold as a silver and copper ore at the
Silver-vein Mine, near Lostwithiel, Cornwall. Indeed this mine is,
and has been worked solely for the silver-fahlerz, no other ore being
found in any useful quantity. The lode (for it is not found in
“pockets” only) runs about 48 degrees east of north and west of
south. Its width appears to have varied considerably, but at the
present time it is about four feet wide. It traverses the ‘ Killas”
or clay-slate of the district and, so far, the ore has become richer in
silver as the depth increases. I know of no accurate analysis having
been made of this ore, so that Mr. Forbes would be doing further
good service to British Mineralogy if he would take such a work in
hand. From eight assays made by Messrs. Johnson and Johnson
and others, some years since, the average yield of silver was 684
576 Correspondence.
ounces to the ton of ore, but the ferruginous gossan at that time con-
tained much silver also, in what form J know not; and I cannot
ascertain whether the gossans were assayed only, or the compact
silver-fahlerz likewise. In one instance the proportion of silver to
the ton of ore was 214 ounces! The last sample sold contained
364 ounces to the ton. Unlike the position of this mineral in the
Fox-dale mine, there is no granite within a distance of two or three
miles. This mine affords the only known instance in this country
of a continuous lode of silver-fahlerz, and, as I have before stated,
no other ore is found in sufficient quantity to be of any commercial
value. The associated minerals are quartz (which in some parts of
the lode is much mixed up with the tetrahedrite) chalybite, and iron-
pyrites. Under the name of Wheal Fortescue, Silver-vein was
formerly worked for the rich deposits of silver it contained; I sup-
‘pose in the state of sulphide, but was abandoned for want of capital.
If Mr. Forbes should be sufficiently interested in the fact as well as
in the mode of occurrence of silver-fahlerz in this locality as to visit
it, can assure him that he will meet with very willing assistance
from my friend, Mr. Talling, of Lostwithiel, who knows every part
of the mine well, and who I have to thank for many of thé above
particulars which I had nearly forgotten, as it is now three years
since I descended it in his company.
I am, Sir, yours very truly,
Brivish Museum. Txos. Davizs.
THE BELGIAN TERTIARIES.
To the Editor of the GrotoctcaL Macazinu.
Str,—I am desirous to correct a mistake which I unintentionally
made in my paper on the Belgian Tertiaries, contained in the
GroLocicaL Magazine of November Ist. I have there stated
(p. 504) that Mr. Searles Wood had remonstrated against certain
views explained by Mr. Godwin-Austen in his paper, “On the
Kainozoic Formations of Belgium.” I now learn from Mr. Searles
Wood that he has not published any paper relating to this subject,
but that the opinions which he had expressed with regard to certain
of Mr. Godwin-Austen’s views were communicated to me in letters
which we exchanged on that subject. I trust to be excused for this
error on the ground that my paper was written at a time when I
had none of my books at hand to refer to, as already stated (p. 506).
—Yours truly, A. von Kornen.
University or Marsure,
November 18th, 1867.
MISCHiUAN HOUS.
We are informed that the collection of M. Deshayes’ Eocene Shells,
from the Paris Basin, forming the types of his great work, “De-
scription des Coquilles Fossiles des Environs de Paris,” which has
occupied so many years in publication, has just been purchased by
the French Government, for the Museum of the Jardin des Plantes,
Paris, for the sum of 100,000 florins.
INDEX.
ACA
CANTHOPHOLIS HORRIDUS,
65, 67.
Aérolites, 124.
Africa, South, Jurassic Fossils of, 128.
Alps, Geology of the, 369.
American Naturalist, 410.
Ammonites transversarius, Zone of, 407.
Anglo-Belgian Basin, 158.
Ansted, D. T., Physical Geography, 266 ;
Physical Geography of Leicester, 162.
Anthracite, hard form of, 240.
Anticosti, Silurian Fossils of, 212.
Antiquity of Man, 74, 76.
Arenig Group of the Silurian system, 113.
Argyll, Duke of, Post-Tertiary Peat-bed
in Argyllshire, 169; Trap and Granite
in the I. of Mull, 553.
Arran Granites, age of, 552.
Aroideous Fruit from the
Slate, 146.
Asaphus, 14.
Asia Minor, Granite of, 406; Palonto-
logy of, 117.
Atlantis in the Early Tertiary Period, 496.
Atrypa, Internal appendages of, 431.
Atthey, T., Fish from the Northumber-
land Coal-field, 378, 424.
Aulophyllun, 416.
Australia, South, Geology and Minera-
logy of, 77.
AILY,W. H., Award of the Wollaston
Donation Fund to, 129; Figures of
Characteristic British Fossils, 464.
Bakewell, F. C., Figure of the Earth, 430.
Bala and Hirnant Limestone, 233, 288.
Banca and its Tin Stream-works, 270.
Banded concretions, 337.
Barbary, Geology of, 420.
Barkas, T. P., ‘Theory of the Earth, 426.
Barrande, J., Bohemian Cephalopoda, 322,
Bath, Hot Springs of, 174.
— Natural History and Antiquarian
Clubs, 174.
Bears, Dentition of, 418.
Bedfordshire, Geology of, 154, 543.
Belgium, Tertiary deposits of, 501, 565,
576.
Stonesfield
Bellerophontide, Affinities of the, 119.
Belt, T., On some new Trilobites from the
Upper Cambrian Rocks, 294; On the
Lingula Flags, of Dolgelly, 493, 536.
Bigsby, J. J., Thesaurus Siluricus, 210.
VOL. IV.—NO, XLII.
BUS
Billings, E., Silurian Fossils of Anticosti,
212
Binney, E. W., Drift of the Western
and Eastern Counties, 231.
Bituminous strata of Gneiss and Mica
Schist in Sweden, 160.
Black, J., Obituary notice of, 288.
Bombay, Geology of the Island of, 165.
Bone-caves in Carmarthenshire, 307; of
Malta, 328.
Bonney, T. G., Kitchen-middens on the
Great Ormeshead, 343; Shells on the
Great Ormeshead, 526; Traces of
Glacial Action near Llandudno, 289.
Bornholm, Geology of the Island of, 25.
Bos longifrons, 167, 536.
Boulder-clay of Norfolk and Suffolk, 479 ;
of the Thames Valley, 430.
-clays, relative ages of the, 97.
Bovey Formation, 393.
Brachiopoda, Perforate and Imperforate,
311, 314, 425
Bravender, J , Water-shed of the Upper
Thames, 422.
Brazil, Coal in, 420.
Brecciated concretions, 337, 481.
Brick-earths, Lower, of the Thames
Valley, 79.
Brigham, W. T., Volcano of Kilauea,
Hawaii Islands, 411.
Bristol Naturalists’ Society, 562.
Bristow, H. W., Lower Lias of Glamor-
ganshire, 216.
British Association, 32, 465, 549-554.
Brodie, P. B., Drift of Warwickshire,
217; Insects in the Carboniferous
Rocks, 285; Purbeck Beds at Brill, 216.
Brown, D.J., and J. Henderson, Silurian
Beds of the Pentland Hills, 220.
Brown, E., Weaver Clays, 381.
—— T., Arctic Deposits of Fifeshire,
508.
T. C., Denudation of Valleys,
139; Trap-dykes and Ancient Forest
in Skye, 521. [552.
Bryce, Dr. J., Age of the Arran Granites,
Bryson, A., Obituary notice of, 47.
Buckinghamshire, Ferruginous Sands of,
457.
Bunter Conglomerates, 173.
Burton, F. M., Rheetic Beds near Gains-
borough, 329.
Busk, G., Dentition of Bears, 418.
37
078
CAM
AMBRIAN Rocks, New Trilobites
Gi from the, 294.
Fossils, 417, 495.
Carboniferous age, Igneous rocks of, 468.
—-~ Limestone, fossils from the,
174; pockets in the, 527.
——- strata, Chitons, from the,
840; Insects in the, 285, 385, 388,
——- Rocks near Bishopbriggs,
221; of North Wales, 11, 92; of
Scotland, Entomostraca of the, 273.
Carruthers, W., On an Aroideous Fruit
from the Stonesfield Slate, 147; Cy-
cadean Fruits from the Secondary
Rocks of Britain, 101; On Cycadeoidea
Yatesii, 199; On Graptolites, 187,
336; On the Systematic Position of
Graptolites, 70.
Casartelli, L. C., Recent Eartiaquakes,
187; Volcanic Disturbance in the
Mediterranean, 239.
Cephalaspid, New, 509.
Cephalaspidean Fishes, New genus of, 152.
Cephalopoda of Bohemia, 322.
Chalk Escarpments, 483; Cliffs, 488.
Chambers, Dr. R., “‘ Eskar,” at St. Fort,
549.
Charnwood Forest, Rocks of, 163.
Cheirolepis from the Uld Red Sandstone,
147.
Chemistry of the Primeval Earth, 357,
426, 433, 477, 525.
Chillesford Beds, Relation of the, to the
Norwich Crag, 129, 560.
China, Geology of, 322. [340.
Chitons from the Carboniferous Strata,
Christy, H., and E. Lartet, Reliquic
Aquitanice, 321. .
Clark, G., Geology of Mauritius, 168.
— W. B., Secondary Deposits in
New South Wales, 26.
Clays and Sands, White, subjacent to
the Boulder-clay Drifts, 241, 299, 335.
Cliffs, 447, 488, 550, 567-575.
Clifton, Gorge of the Avon at, 444,
Close, M. H., General Glaciation of
Treland, 167, 234.
Coal-field of South Staffordshire, Pro-
bable Duration of the, 263.
-measures of Scotland, Fossils from
the, 130.
of Northumberland, Fishes from
the, 328, 424; of Nova Scotia, 73, 74;
of the Andes, 216; of Brazil, 420;
of Russia, 265.
—— Resources of India, 264.
— Supply, 94. ;
Cochliodonts, Mandible and Mandibular
Teeth of, 59.
Coemans, E., Cretaceous Flora of Hai-
naut, 319.
Colliery Explosions, 106.
Index.
DAW
Collingwood, C., Sulphur Springs of
Formosa, 420.
Concretions, Banded and Brecciated, 337,
Continents, Origin of, 223. [481.
Conulus priscus, 417.
Cope, Professor, Dinosaurian from New
Jersey, 93.
Coprolite Workings in the Fens, 309.
Corals from the Infra-Lias of South
Wales, 27.
Cornwall, Royal Geological Society of, 23.
Cotteswold Naturalists’ Field Club, 372,
422.
Crag Deposits of England and Belgium, 91.
, Rhynchoceti of the, 191,
Crags, Upper and Lower, in Norfolk, 331.
Cretaceous Flora of Hainaut, 319.
— Fossils of South Bedfordshire,
157.
Rocks of Britain, 456; of
Norfolk and Kent, 29.
Crickitt, R. E., Hot Springs of Bath, 174.
Crinoidea, 16.
Crookesite, 528.
Crustacea from Styria, Triassic, 319.
, New genus of, from the Coal-
measures, 320; from the London and
Plastie Clays, 529, 531. [29.
Curry, J., Drift of the North of England,
Cycadean Fruits from the Secondary
Rocks of Britain, 101.
Cycadeoidea Yatesii, 199.
Cyclophyllum, 416.
Cyrtina heteroclita, 255, 314.
Ue COSTA, P., Tertiary Fossils of
Portugal, 407.
Damon, R., On a Collection of Recent
Shells from the Ruins of Pompeii, 293.
Davidson, T., Perforate and Imperforate
Brachiopoda, 311.
Davies, D. C., Bala and Hirnant Lime-
stones, 283 ; Ona Bed of Phosphate of
Lime in North Wales, 251; Lower Car-
boniferous Rocks of North Wales, 92.
—- T., Senarmontite in Cornwall,192 ;
On Silver-Fahlerz, 575.
Dawkins, W. B., Boulder-clay of the
Thames Valley, 430; Lower Brick-
earths of the Thames Valley, 79; On
Bos longifrons, 167; On &hinoceros
leptorhinus, 218; Age of the Thames
Valley Deposits, 574.
Dawson, J. W., Coal Discoveries and
Primordial Fossils in North America,
73; Discoveries in regard to Hozoén
Canadense, 222, 326; Insects from the
Carboniferous and Devonian forma-
tions, 874; On Paleozoic Insects re-
cently discovered in Nova Scotia and
New Brunswick, 3885; Pulmonate
Mollusk in the Coal-formation, 417.
Index.
DEL
Delesse, A., and De Lapparent, Revue
de Geologie, 322.
Denudation, 3, 89, 133, 186, 139, 184,
236, 295, 327, 345, 412, 447, 483, 545.
Derbyshire, Clay-bed near Stannage, 425.
Deslongchamps, J. A. E., Obituary
notice of, 140.
Devon, North, Physical Structure of, 272.
Devonian Fossils, 419.
—— Rocks, Fish in the, 134, 188,
232, 284, 335.
—__—_ —of Devonshire, 42, 87.
Devonshire, Geology of, 295, 390.
Dick, R., Obituary notice of, 142.
Didymaspis, 152.
Diest, P. van, Banca and its Tin Stream-
works, 270.
Dinosaurian from New Jersey, 93.
Dolgelly Lingula, Flags of, 493, 536.
Dolomite, Formation of, 366, 441.
Dredging among the Hebrides, 32.
Drift, Faults in the, 89, 90, 182.
at Hitchin, Faults in the, 37, 40.
— Deposits of the Eastern Counties,
189, 276, 371, 374, 426, 479.
of the Western and Eastern Coun-
ties, 231.
of Lancashire and the Eastern
Counties, 183, 281.
of the North of England, 29.
of Warwickshire, 217.
—— of Suffolk, Consolidated Blocks in
the, 126.
Dumas, M., Hard form of Anthracite,
240.
Duncan, P. M., British Fossil Corals
480; Carboniferous Corals, 416, 480;
Liassic Corals, 480; Cretaceous Echino-
dermata from Sinai, 28 ; Madreporaria
of the Infra-lias of South Wales, 27.
ARTH, Figure of the, 430.
Earth, Origin of the, 434.
Karthquakes, Recent, 187.
Eastern Counties, Drift of the, 183, 189,
276, 281, 371, 374, 426, 479.
Echinodermata, Cretaceous, from Sinai, 28.
Edinburgh Geological Society. 170, 219.
Egypt, Upper, Geology of, 28.
Elephants, Teeth of, from the Norfolk
Forest-bed, 421.
Entomostraca of the Carboniferous Rocks
of Scotland, 273.
Eozoon, Organic nature of, 176, 222, 326,
376.
Eruptive Rocks, 512.
Escarpments, 184, 236, 447, 483.
“ Hskar’’ at St. Fort, 549.
Etheridge, R., Physical structure of
North Devon, 272; On the Strati-
graphical position of -Acanthopholis
horridus, 67.
579
GLA
HKyton, Miss, On an Old Lake-basin in
Shropshire, 1; on Glacio-marine
Denudation, 545.
JAUDEL, M., Human Remains in the
Lehm, 74.
Faults in the Drift, 37, 40, 89, 90, 182.
Ferruginous Sands of Buckinghamshire,
Festiniog Group, 493. [456.
Fife, Geology of, 166.
Firth of Forth, Cliffs, etc., of, 550.
Fish, Fossil, of Mount Lebanon, 72; of
the Devonian Rocks, 134, 188, 282,
284; of the Old Red Sandstone, 232.
—,, Osteology of, 222; Otolites of, 161.
Remains from the Northumberland
Coal-field, 323, 378, 424.
Fisher, O., Ages of the “ Trail’ and
“Warp,” 193; Faults in the Drift
and ‘ Trail,” 90; Relation of the
Chillesford Beds to the Norwich Crag,
Flint Cores from the Indus, 43. [129
Flora, Keuper, of North Tyrol, 406.
—of Hainaut, Cretaceous, 319.
Foliation of Metamorphic Rocks, 93.
Foot, F. J., Obituary notice of, 95, 182.
Forbes, D., Chemistry of the Primeval
Earth, 433; The Microscope in Geo-
logy, 511; On the Alleged Hydro-
thermal origin of certain Granites and
Metamorphic Rocks, 49, 265. 22 5
Forest, Ancient, in Skye, 521.
-bed, Elephant remains from the,
421; of Carboniferous Age in Arran,
552.
Forests, Buried, of Scotland, 20.
Fossils, Characteristic British, 464. [543.
of South Bedfordshire, List of, 157,
Foster, C. Le N., Banca and its Tin
Stream-works, 270.
Freiburg, Mining Society of, 18.
Furness, Moulded Limestones of, 401.
EIKTE, A., Address to the Geological
Section of the British Association,
465; Geological Time, 171; Tertiary
Voleanic Rocks of the British Islands,
ol6.
J., Buried Forests and Peat
Mosses of Scotland, 20; Hydrothermal
origin of certain Granites and Meta-
morphic Rocks, 176, 287.
Geological Society of London, 26, 78,
126, 167, 215, 272, 326, 369, 416, 556.
Survey of Great Britain, 192.
Time, 171.
Geologists Association, 561.
Gibbens, W., Pholas-borings in Devon-
shire, 429.
Glacial Action near Llandudno, 289;
Deposits of Fifeshire, 508, 549; on
the East Coast, 371, 374,
080
GLA
Glacial-period in England, 78, 82.
Glaciation in Devon, 41; of Ireland,
167, 234.
Glacio-marine denudation, 545.
Glasgow Geological Society, 80, 130,
172, 220, 273, 557.
Godwin-Austen, R., on the Belgian
Tertiaries, 565.
Gold in New Brunswick, 215.
Goniocypoda Edwardsi, 529.
Graham, T,, Occlusion of Hydrogen by
Meteoric Iron, 288.
Granite, Eruptive, in Asia Minor, 406;
in Devonshire, 397; in I. of Mull, 553.
, Origin of, 49, 176, 265, 287,
442, 522; Age of Arran, 552.
Graptolites, 70, 107, 185, 187, 238, 256,
336
Green, A. H., On the Lower Carboniferous
Rocks of North Wales, 11; White
sands and clays subjacent to the Boul-
der-clay, 335; On the Valley of the
Ouse at Buckingham, 563.
Greenwood, G., Pre-historic settlements,
42; Inundations and their prevention,
86; Rain and Rivers, 412; The Lob-
worm Epoch, 383; Valley Terraces, 205.
Gregory, J. R., Elementary Geology and
Mineralogy, 510.
Greywacké, Definition of, 229.
Grey-Wethers at Grays, Essex, 63.
Gunn, J., Coast Sections of Norfolk and
Suffolk, 871; Recent Deposits in the
Valleys of Norfolk, 519; Teeth of
Elephants from Norfolk, 421; The
Anglo-Belgian Basin, 158.
Guppy, R. J. L., Nature of Hozodx, 376 ;
On West-Indian Geology, 496.
AAST, J., Geology of Canterbury,
New Zealand, 418.
Hall, T. M., North Devon Fossils, 419.
Hamilton, W.J., Obituary notice of, 383.
Harkness, R., Fossils of the Upper Llan-
dovery Rocks, 286.
Harmer, F. W., Drift of the Eastern
Counties, 374: Third Boulder-elay in
Norfolk, 79.
Hawaii Islands, Volcano of, 411.
Hawkshaw, J. C., Geology of Upper
Egypt, 28.
Hebrides, Dredging among the, 32.
Helmersen, G. de, Coal of Russia, 265.
Henderson, J., and D.J. Brown, Silurian
Beds of the Pentland Hills, 220.
Hicks, H., Hyena-den in Carmarthen-
shire, 807 ; Lob-worm Epoch, 428.
Higgins, KE. f., Otolites of Fish, 161.
Himalayas, Geology of the, 369.
Histoire Elementaire des Mineran Usuels,
555. (America, 34.
Hitchcock, C. H., Petroleum in North
Index.
KIN
Hodgson, E., On the Moulded Limestones
of Furness, 401.
Home, D. Milne, Cliffs and Banks of the
Firth of Forth, 550.
Hooker, J. D., Struggle for existence
amongst Plants, 415.
Hot Springs of Bath, 174.
Hughes, T. M’K., On the Break be-
tween the Upper and Lower Silurian
Rocks of the Lake District, 346.
Hull, E., Faults in Drift, 182; Paral-
lelism of the Drift Deposits in Lan-
cashire and the Eastern Counties, 183 ;
On Denudation, 567.
Humbert, A., and F. J. Pictet, Fossil
Fish of Mount Lebanon, 72.
Hungary, Oligocene Deposit in, 2i1.
Hunt, f. S., The Chemistry of the
Primeval Earth, 357, 477 ; Mineralogy
of Crystalline Limestones, 175; Origin
of Continents, 223.
Huxley, T. H., New specimen of Te/er-
peton Ellginense, 78; Onanew Reptile
from the Chalk-Mazrl, 65.
Hyzena-den in Carmarthenshire, 307.
GELSTROM, L. J., Bituminous strata
of Gneiss and Mica Schist in Sweden,
160.
Igneous Rocks of Ayrshire, 131; of the
British Isles, 465.
India, Coal Resources of, 264.
Insects from the Carboniferous and De-
vonian formations, 374; in the Car-
boniferous Rocks, 285.
, Paleozoic, 385, 388.
Intellectual Observer, 416.
Ireland, Glaciation of, 167, 234.
A eae J. G., Dredging among
the Hebrides, 32; Shetland Isles, 554.
Jevons, W.8., Probable duration of the
South Staffordshire Coal-field, 263.
Jones, T. R., and J. W. Kirkby, En-
tomostraca of the Carboniferous Rocks
of Scotland, 273.
Judd, J. W., Geology of the Lincoln-
shire Wolds, 218.
Jukes, J. B., Devonian Rocks of Devon-
shire, 87; Glaciation in Devon, 41;
Gorge of the Avon, 444; The late
Mr. F. J. Foot, 132. —‘[ Africa, 128.
Jurassic Fossils of Poland, 320; of South
AIMENT Islands, Volcanic eruptions
at the, 408.
Kent, Cretaceous Rocks of, 29.
Kent’s Cavern, 297.
Keuper Flora of North Tyrol, 406.
Kinahan, G. H., Denudation and the
form of the ground, 89; Cliffs and
Escarpments, 569.
Index.
KIN
King, W., On some Perforated Paleozoic
Spiriferide, 253; Spirifer cuspidatus
and Syringothyris typa, 425.
King-Crab in the Upper Silurian, 528.
Kirkby, J. W., On Insects from the
‘Coal-measures of Durham, 388.
and J. Young, On some remains
of Ohiton and Chitonellus from the
Carboniferous strata, 340.
Kitchen-Middens on the Great Ormes-
head, 343, 377, 533.
Koenen, A. von, On the Belgian Ter-
tiaries, 501, 576.
Kongsberg, Occurrence of Silver at, 18.
AKE District, Geology of the, 346.
Lake-basin in Shropshire, 1.
Lancashire, Drift of, 183, 281.
Lankester, E. R., Crag Deposits of
England and Belgium, 91; New Cepha-
laspid, 509; On Didymaspis, a new
genus of Cephalaspidean Fishes, 152.
Lartet, E., and H. Christy, Reliquize
Aquitanice, 321.
Laube, G. C., Fossils of the Brown Jura,
320.
Leicester, Physical Geography of, 162.
Le Hon, H., Fossil Man in Europe, 76.
Lias-conglomerate of Glamorganshire,
216.
Limestones, Mineralogy of crystalline, 175.
Lime, Phosphate of, in North Wales, 251.
Lines on a Scratched Boulder, 94.
Lincolnshire Wolds, Geology of the, 218.
Lingula Flags, 493, 536.
Lingulella from the Lower Cambrian
Rocks, 417.
Lightbody, R., Meetings of Societies, etc.,
44,
Lithodomous Perforations in Limestone
Cliffs, 188, 295, 429.
Lithological Nomenclature, 83.
Liverpool Geological Society, 82.
Llandeilo Group of the Silurian system,
113.
Llandudno, Kitchen-middens at, 533.
Llandovery Rocks, Upper, Fossils in the,
286.
Lob-worm Epoch, 428.
Logan, W. E., New specimens of Hozoon,
326.
London, Surface-Geology of, 510.
Liitken, C., Pentacrinites of the West
Indies, 16.
Lyell, C., Principles of Geology, tenth
edition, 120.
Mo F., On the Occurrence of the
genus Sgualodon in the Tertiary
strata of Victoria, 145.
Maclaren, C., Geology of Fife and the
Lothians, 166,
d81
MOL
Mackintosh, D., Curvature of Slaty La-
mine, 370; Denudation, 136; On
Escarpments, 236; Pholas-borings,
Denudation, and Deposition in S.E:
Devon, 295; Railway Geology, from
Exeter to Newton Bushel, 390; On
Denudation, 571.
Malta, Bone-caves of, 328.
Malvern Hills, Chemical Geology of the,
418.
Mammalian remains from Hungary, 407 ;
in the Lehm, 74.
Man, Fossil, in Europe, 76.
Manchester Geological Society, 81.
—- Literary and Philosophical
Society, 132.
Mauritius, Geology of, 168.
Maw, G., Consolidated Blocks in the
Drift of Suffolk, 126; Drift Deposits
of the Eastern Counties, 276, 426; On
some Chemical Analyses of variegated
strata, 127; On the Distribution be-
yond the Tertiary Districts of White
Clays and Sands subjacent to the Boul-
der-clay Drifts, 241, 299; Relative
ages of the Boulder-clays, 97 ; Shells
on the Great Ormeshead, 377; White
Clays of the Lower Tertiaries, 420;
Cambrian Rocks of Llanberis, 553.
May Hill Sandstone, 174, 201.
Mediterranean, Volcanic disturbance in
the, 239.
Medlicott, H. B., Lithological Nomen-
clature, 83; The Alps and the Hima-
layas, 369.
Meek, F. B., Affinities of the Bellero-
phontide, 119; Euproops, a new Crus-
tacean, 320; Punctate Shell-structure
of Syringothyris, 315.
Mello, J. M., Clay-bed near Stannage,
Derbyshire, 425; Pockets in the Car-
boniferous Limestone, 527; Kitchen-
Middens at Llandudno, 533.
Metamorphic Rocks, 49, 176, 265, 287,
522; Foliation of, 93.
Meteoric Iron, Occlusion of Hydrogen
by, 288.
Meteorites, 124.
, New classification of, 192. -
Microscope in Geology, 511.
Milne-Edwards, Dr. A., On Necrozius
Bowerbankii, 631.
Mineralogy of Crystalline Limestones,175.
Mineraux Histoire des Elementaire, 556.
Mining, Lectures on, 93, 191, 323.
Mollusca from the Caribean Miocene
deposits, 500, Recent species of, from
the ruins of Pompeii, 298.
Moilusk, Pulmonate, in the Coal-forma-
tion, 417.
Molyneux, W., Gravel Beds of Trentham
Park, 173.
O82
MON
Montreal Natural History Society, 175,
222, 374.
Moore, C., Secondary deposits of Somer-
setshire and South Wales, 217.
Morris, J., On the occurrence of Grey-
Wethers, at Grays, Essex, 63; On the
Ferruginous Sands of Buckingham-
shire, 456.
Morton, G. H., Glacial Ice in the Valley
of the Mersey, 82.
Mountain Limestone, Fossils from the,174.
Mull, Trap and Granite of, 553.
ECROZIUS BOWERBANKTI,
d3l.
New Brunswick, Primordial Fossils in,73.
New Red Sandstone formation of Staf-
fordshire, 173.
New South Wales, Secondary deposits
in, 26.
New Zealand, Geology of Canterbury, 418.
Nicholson, H. A., Fossils in the Old Red
Sandstones of Westmoreland, 170;
Graptolites, 238; Graptolites of the
Moffat Shales, 185; Lower Silurian
Fossils from Scotland, 107; New
genus of Graptolites, 256.
Norfolk, Cretaceous Rocks of, 29; Geo-
logy of, 371, 374; Recent deposits i in
the valleys of, 519.
North Staffordshire Naturalists’ Field-
club, 172.
Norwich Crag, Relation of the Chillesford
Beds to the, 129.
Norwich Geological Society, 29, 83, 380,
371, 519, 560.
Nova Scotia, Coal discoveries in, 73, 74.
Nucula Cobboldie, Recent specimens of,
330.
BITUARY notices of Dr. J. Black,
288; A. Bryson, 47; Dr. J. A. E.
Deslongchamps, 140; R. Dick, 142
Ensign H. A. Wyatt- -Edgell, 46 ; P
J. Foot, 95; W. J. Hamilton, 383;
Cay. A. Parolini, 192; Senor C. di
Prado, 48; J. Smith, 141.
Odontoloyical Society of London, 323.
Ogygia, 14.
Oldham, T., Coal Resources of India, 264,
Old Red Sandstone, Cheirolepis from the,
147; Fish in the, 232, 333; Igneous
Rocks associated with the, 467.
in Dumbuck Glen, 132; of
Westmoreland, Fossils in the, 170.
Oligocene Deposit in Hungary, 211.
Opal, Treatise on, 214.
Oppel, A., Zone of Ammonites transver-
sarius, 407.
Ormerod, G. W., Geology of the Teign
Valley, 168.
Otolites of Fish, 161.
Index.
REY
Owen, R., Genera of Fish from the Coal
of Northumberland, 323, 424; On the
Mandible and Teeth of Cochliodonts, 59.
ALAONTOGRAPHICAL Society,
Monographs of the, 122, 409, 562.
Parolini, A., Obituary notice of, 192.
Peat-bed in ‘Kintyre, 169.
Mosses of Scotland, 20.
Pengeily, W., Fish in Devonian Rocks,
284.
Pentacrinites of the West Indies, 16.
Perigord, Paleontology of, 321.
Permian age, Ioneous rocks of, 469.
Petroleum in North America, 34.
Phipson, T. L., Meteorites, Aérolites,
and Falling Stars, 124.
Pholas- borings i in Devonshire, 188, 295,
429.
Phosphate of Lime, Bed of, in North
Wales, 251.
ae Geography, 266; of Leicester,
Pichler, A., Keuper Flora of North
Tyrol, 406.
Pictet, F. J., and A. Humbert, Fossil
Fish of Mount Lebanon, 72.
Pisani, F., Analysis of a Black Spinelle,
432.
Planets, Densities of, 426.
Plant, J., Ancient sea-beach near Buxton,
81.
Plesiosaurus, New species of, 144.
Popular Science Review, 415.
Portugal, Tertiary Gasteropods of, 407.
Post-glacial structure of the south-east
of England, 421.
Potton Sands, Cycadeanstem from the,199.
Powrie, J., Fish in the Old Red Sand-
stone, 383; On the genus Chetrolep’s,
from the Old Red Sandstone, 147.
Prado, Senor O. di, Obituary notice of, 48.
Princess Islands, Geology of the, 419.
Proboscideans, Distribution of, 160.
Pteraspis, Tracks of, 417.
Pumpelly, R., Geolozy of China, Mon-
golia, and J apan, 322.
Purbeck Beds at Brill, Buckinghamshire,
216.
UARTERLY Journal of the Geolo-
logical Society, 124, 413.
of Science, 75, 415.
Quartz, Treatise on, 214.
AIN and Rivers, 412.
Reliquize Aquitanice, 321.
Reptile, New, from the Chalk-marl, 65,
Reuss, A. E., Triassic Crustacea from
Styria, 319.
Reynaud, Histoire Elementaire des
Mineraux Usuels, 555.
Index.
RH
Rhetic Beds near Gainsborough, 329.
Rhinoceros leptorhinus, Dentition of, 218.
Rhynchoceti of the Crag, 191.
Rock-basins, 398.
veins, 481.
Rocks, Eruptive, 512; Sedimentary, 514.
Rofe, J., Note on the late Colliery Ex-
plosions, 106.
Rose, C. B, Cretaceous Groups of Norfolk
and Kent, 29.
Ruskin, J., On Banded and Brecciated
Concretions, 337 ; On Brecciated For-
mations, 481.
Russia, Coal of, 265.
ALTER, J. W., Bala and Hirnant
Limestone, 238; Devonian Rocks
of North Devon, 42; Faults in the
Drift at Hitchin, 40; Fish in the
Devonian Rocks, 134; Fish in the
Old Red Sandstone, 232; On the May
Hill Sandstone, 201; Tracks of Pteras-
pis, 417; Lingulella from the Lower
Cambrian Rocks, 417; Upper Devonian
in South Devon, 335.
Saltness of the sea, Origin of the, 438.
Sands, White Clays and, subjacent to the
Boulder-clay Drifts, 241, 299, 335.
Santorin, the Volcanic Eruptions at, 408.
Sarsen-stones, 63.
Saunders, J., On the Geology of South
Bedfordshire, 154, 543.
Scheerer, Professor, Occurrence of Silver
at Kongsberg, 18.
Scratched Boulder, Lines on a, 94.
Scrope, G. P., Award of the Wollaston
medal to, 129.
Sea, Encroachment of the, 410; Theory
of the saltness of the, 438.
Sea-marks, Ancient, on the coast of
Sweden, 169.
Secondary deposits of Somersetshire and
South Wales, 217. [of, 43.
Sedgwick, Professor, Biographical notice
Sedimentary Rocks, 514.
Seebach, K. von, Geology of the Island
of Bornholm, 25.
Selkirk, Earl of, Ancient sea-marks on
the coast of Sweden, 169.
Serpentine, Eruptive, in Asia Minor, 406.
Shea, W.S., Gold in New Brunswick, 215.
Shells on the Great Ormeshead, 377, 526.
Shepard, C. U., New classification of
Meteorites, 192.
Silurian age, Igneous Rocks of, 466.
beds of the Pentland Hills, 220 ;
Fossils of Anticosti, 212.
Rocks, Break between the Upper
and Lower, 346.
Silver at Kongsberg, Occurrence of, 18.
fahlerz in Cornwall, 578.
Sinai, Cretaceous Echinodermata from, 28.
583
TRA
Skipsey, R. W., Igneous Rocks of Ayr-
shire, 131.
Skye, Geology of, 521.
Slaty laminze, Curvature of, 370.
Sligo, Notes on Glen-car Valley, 346.
Smith, J., Obituary notice of, 141.
South Beds., Geology of, 154, 543.
Spimelle, Analysis of a, 432.
Spirifer cuspidatus, 253, 311, 316, 425.
Spratt, T. A. B., Bone-caves of Malta,328.
Squalodon, Occurrence of, in the Tertiary
strata of Victoria, 145.
Stacey, G. B., Geology of Benghazi,
Barbary, 420.
Staffordshire, Gravel-beds in, 173.
Stonesfield Slate, Aroideous Fruit from
the, 146.
Sulphur Springs of Formosa, 420.
Swan, W. R., Geology of the Princess
Islands, 419.
Sweden, Ancient sea-marks on the coast
of, 169; Bituminous strata of Gneiss
and Mica Schist in, 160.
Syringothyris typa, 311, 315.
NATE, R., Jurassic Fauna and Flora
of South Africa, 128; Lower Lias
of the north-east of Ireland, 329;
Zone of Ammonites angulatus in Great
Britain, 329.
Taylor, J. E., Drift deposits in Lan-
eashire and Norfolk, 281; Upper and
Lower Crags in Norfolk, 331.
Tchihatchef, P. de, Granite of Asia
Minor, 406; Paleontology of Asia
Minor, 117.
Teign Valley, Geology of the, 169.
Telerpeton Eiginense, New specimen of,78.
Terebratulide from Upware, 454.
Tertiary age, Igneous Rocks of, 470.
— Clays, Origin of White, 420.
— Deposits of Belgium, 501, 565,
576.
— Escarpments, 486; Cliffs, 489.
—- Gasteropods of Portugal, 407.
— Voleanic Rocks, British, 316.
Thames Valley, Boulder-clay of the, 430
Lower Brick-earths of the, 79.
, Watershed of the, 422.
Thesaurus Siluricus, 210.
Thomas, J. E., Encroachment of the sea
between the River Mersey and the
Bristol Channel, 410.
Thornton, E., Coal in Brazil, 420,
Timins, J. H., Chemical Geology of the
Malvern Hills, 418.
Tin Stream-works of Banca, 270.
Topley, W., Origin of Kscarpments, 184.
Tors of Dartmoor, 399.
Trail, Age of the, 193. [Opal, 214.
Traill, G. W., Treatise on Quartz and
Trap and Granite of Mull, 453,
584
TRA
Trap-dykes in Skye, 521.
Triassic age, Igneous Rocks of, 470.
Crustacea from Syria, 319.
Trilobites, New, from the Cambrian
Rocks, 294; The Genera of, 14.
Twemlow, G., Flint Cores from the Indus,
43,
i eases workings at,309 ;
New Terebratulide from, 464.
Ursus, Dentition of, 418.
ALLEYS, Denudation of, 139; of
Norfolk, Recent Deposits in the,
519, 560.
Valley Terraces, 205.
Variegated strata, Chemical Analyses of,
127.
Volcanic disturbance in the Mediter-
ranean, 239.
— Rocks, British Tertiary, 316,
Volcanos, Ancient British, 465.
—— of Kilauea, Hawaii Islands,
411; of Santorin, 408.
Va New species of,
454.
Walker, J. F., On new Terebratulide
from Upware, 454; On some new
Coprolite workings in the Fens, 309.
Warp, Age of the, 198.
Watershed of the Upper Thames, 422.
Wealden beds in Buckinghamshire, 457.
Weaver Clays, 335, 381.
West-Indies, Geology of the, 496.
Westropp, W. H. S., Origin of Granite,
622.
Wheelwright, W., Coal of the Andes, 216,
Whitaker, W., On Subaérial Denudation,
327, 447, 483; Surface-Geology of
London, 510.
Index.
ZIP
Whitfield, R. P., Notes on Aérypa, 431.
Winchell, A., and O. Maury, Fossils
from the Limestone at Chicago, 25.
Wood, 8. V., jun., Boulder-clay and
Drift of the Eastern Counties, 479;
Drift deposits of the Kastern Counties,
189, 375; Faults in the Drift at
Hitchin, 37, 40; Post-glacial structure
of the south-east of England, 421 ; Sec-
tion at Litcham, 78.
Woods, J. E. T., Geology and Mineralogy
of South Australia, 77.
Woodward, H., Fossils from the Coal-
measures of the West of Scotland, 130 ;
Structure of the Xzphosura, 27 ;
Gontocypoda Edwardst, 529.
Wiinsch, E.A., Fossil Trees of Arran, 551.
Wyatt-Edgell, H., On the Arenig and
Llandeilo Groups, 113; On the Genera
of Trilobites, 14.
————, Obituary notice of, 46.
Wyatt, J., Alteration in the coast-line
of Norfolk, 554.
Wynne, A. B., On Denudation, 3, 133 ;
Faults in the Drift, 89; Geology of
the Island of Bombay, 165; On Glen-
ear Valley, Sligo, 345.
IPHOSURA, Structure of the, 27.
Discovery of, in U. Silurian
Rocks, 528.
OUNG, J., Carboniferous Rocks near
Bishopbriggs, 221; Osteology of
Fishes, 222. Address, 558.
—_ Sections in the Old Red Sand-
stone, 132.
aa Recent Skull of, 94.
STEPHEN AUSTIN, PRINTER, HERTFORD.
. 7
> . .
.
‘
ee
e \ i
SM o
a
»
J -
:
.
;
t
‘
* *
7 . / ‘
z
9 at
*
, r=
;
'
i
‘
wid bak
SERIAL
CO Oe GR MEC ice Co ee Le C
COE EE eS SSS aay
. Oe Ce GCE &
Pert ae
Ci
Fr C ar
i a CC & = ; :
\ x Xv GK at« pee
x ; <_ » 4 me Ce Wea, €
«e . are +
i ce! ‘
ry MHS \
= COC
4 Mi Ges
1 Ke OS
CCC CCE €
a '