Dura Den : a monograph of the yellow sandstone and its remarkable fossil remains

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DURA DEN

A MONOGRAPH OF THE YELLOW SANDSTONE

AND ITS REMARKABLE FOSSIL REMAINS.

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DURA DEN

A MONOGRAPH OF THE YELLOW SANDSTONE

AND ITS REMARKABLE FOSSIL REMAINS.

JOHN ANDERSON, DD. F.GS. EPS, Eve.

AUTHOR OF ‘‘ THE COURSE OF CREATION,” ‘‘ GEOLOGY OF SCOTLAND,” ETC.

ith Allustrations.

KDINBURGH: THOMAS CONSTABLE AND CO,
HAMILTON, ADAMS, AND CO., LONDON.

MDCCCLIX,

[The Author reserves the right of Translation. |

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AND

SIR RODERICK I. MURCHISON, G.C.S7.8. D.O.L. V.P.R.S. Ere.

ACTIVE COADJUTORS IN THE FOSSIL DISCOVERIES

‘

OF SEPTEMBER 16, 1858,

THIS VOLUME IS RESPECTFULLY DEDICATED

BY

THE AUTHOR.

LIST OF ILLUSTRATIONS.

VieNnErTE OF Dura Den, Coloured, : : ; ; Titlepage.
Map oF THE District, Geologically Coloured, , : : PAGE 5

SECTIONS SHOWING THE SERIES OF Rock Groups, PRIMARY AND SECONDARY, 21

PLATES—

I.—First Group of Fossil Remains found in Dura Den, : : 49
II.—Figure of Glyptopomus Minor, , : ; : 55
IlI.—Figure of Glyptoleemus Kinnairdi, . : : 2 ; 63
IV.—Perfect Figure of ditto, : ; ary: 2 5 65
V.—Figure of Phaneropleuron Andersoni, : : ‘ : 67
VI.—Full Jugular Aspect of ditto, ‘ : ‘ : : 69
VIL—Fieure of the large Holoptychius, . : : ; : 73
VIII.—Group of Fossil Remains, . F . : , : 96

Woopcuts—
Sphenopteris Affinis, in the Dura Den Carboniferous Sandstone, . 48
Heterocercal and Homocercal Fins, : : ; , 39

Holoptychius Nobilissimus,
New Delineation of the type Holoptychius, 71

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MONOGRAPH OF DURA DEN,

INTRODUCTORY.

THE yellow sandstone deposits of Dura Den have excited
considerable interest among geologists for many years, and
recently they have become still more worthy of notice. The
Poissons Fossiles of Agassiz contain descriptions of their
organic remains which have given celebrity to the locality in
every quarter of the world. The autumn of last year intro-
duced them for the first time to the personal acquaintance of
the illustrious author of the Siuria. Sir Charles Lyell visited
Dura Den, in company with myself, in the summer of 1842;
and in the same year Dr. J. Malcolmson, on his return from
India, was attracted by the fame of their rich fossiliferous beds
to examine and note their relations to the Elgin and Morayshire
sandstones. Hugh Miller was an explorer in this fertile and
controversial field. Dr. Fleming had closely examined every
rock and quarry in the ravine and the vicinity for miles round.
As his “daily haunt and neighbourhood,” my ever-active and
distinguished friend, Dr. George Buist of Bombay, made Dura
Den the scene of his constant explorations, while, by his excel-
lent text-books and otherwise, Mr. Page has contributed much
to elucidate and extend the knowledge of its interesting fossil
remains.

My own descriptions and speculations are successively re-
corded in Fife Illustrated ; in the gold medal “ Prize Essay,”

A

2 MONOGRAPH OF DURA DEN.

published in the Agricultural Transactions for 1840; in the
Course of Creation, where a chapter is devoted to the consi-
deration of the yellow sandstone of Dura Den; and in the
Edinburgh New Philosophical Journal.

More recently, and since the publication of these works, seve-
ral additions have been made to the collection of the interesting
organic remains. The 16th day of September, 1858, will ever
be memorable in the annals of Dura Den, when, in presence of
Sir Roderick J. Murchison, Lord and Lady Kinnaird, and a
distinguished party from Rossie Priory, the largest fossil Holo-
ptychius ever discovered was exhumed from the rock, in full and
perfect outline and entireness, and measuring upwards of three
feet in length. A great many specimens of smaller dimensions
were obtained on the same fortunate occasion. Another trial
was made about two months afterwards by the proprietors, Mr.
and Mrs. Dalgleish of Dura, when a considerable space of rock
being first cleared of superficial detritus, nearly a THOUSAND
fossil fishes were lifted from their stony bed of ages! Many
of these were of large dimensions, and their several organs of
heads, teeth, scales, and fins beautifully preserved. The pre-
vailing family is that of the holoptychius, but along with these
some entirely new forms were discovered ; portions of former,
but imperfect and undescribed genera and species were detected
by us among the trophies of the day; and hence the more
immediate occasion furnished to the author for now wnder-
taking this monographical record of a locality so remarkably
rich in the numbers and variety of its fossiliferous treasures.

This classic field of geology has some special attractions in
itself, besides those arising from its forms—“ new and strange”
—in its rocky foundations. No lover of the beautiful can fail
to be arrested by the fine grouping of objects that successively
fall upon the eye in traversing the ravine, enclosed by high
precipitous rocks on both sides, and which are diversified by
the various colours of their interlaminated beds of shales and
sandstones, of traps and ironstones. The mansion-houses of

INTRODUCTORY. 3

Dura, Blebo, and Kemback, nestle on the sloping banks of the
dell, amidst stately clusters of plantation ; the church and
manse occupy an elevated plateau in a bay of the rock; the
ever-busy mills, and their neat workmen’s cottages, are seen at
intervals beneath ; the Castle of Dairsie stands in ruins in the
close vicinity of the parish church, the erection of Archbishop
Spottiswoode, still in perfect preservation, and the former famed
in Scottish story as the house of parliament in which were
discussed the contending claims of Bruce and Baliol. Here, in
the caverns of the rock, persecuted saints have found a refuge
in covenanting days ; a short detour to the left presents a sight
of Magus Muir, of cruel memory and most indefensible policy ;
and nearer to the right are the lands of Pitscottie, the birth-
place and retreat of Robert Lindsay, the learned author of the
History of Scotland.

No apology therefore is required for a separate Memoir of
a locality combining so many points of historic interest and
geologic illustration. Dura Den ranks with the celebrated de-
posits of Cromarty, Caithness, Elgin, Isle of Higg, Clashbennie,
Babruddery, and Carmylie, in their vast stores of organic ~
remains, while it presents as yet a monopoly of several genera
and species of the ganoid order of fishes—the precise types of
organic life, and beautiful enamelled forms of the yellow sand-
stone of the district, being nowhere else discovered in any of
our geological formations. Lying nearly equidistant between
the firths of Forth and Tay, the county town of Cupar, and
the city of St. Andrews, the railway traverses the opening of
the Den, and on every side it is of the easiest access.

Dura Den, thus distinguished in its local and archeological
connexions, is about two miles in length in its direct lineal
extension from the church of Spottiswoode to the lands of
Pitscottie. The record of events of their own time, by these
celebrated chroniclers, is perhaps less trustworthy than the
legends inscribed on the rocks beneath, of creatures that battled
in their hard scaly armature, and in the far antepast of geologic

4 MONOGRAPH OF DURA DEN.

times ; whose families have become utterly extinct amidst
revolutions and convulsions by which sea and land have inter-
changed places, and whereby the physical aspects of all around
have been modified or produced ; and now entombed in their
marble sepulchres—

“ Sand hath fill’d up their palaces of old,
Sea-weed o’ergrown their halls of revelry.”

The arrangement proposed to be followed in this Memoir will
comprise,—

I. A general topographical description of the district.

II. The geological position of the yellow sandstone, and its
relations to the Primary, Devonian, and Carboniferous systems.

III. History of the fossil remains.

IV. Descriptions of the fossil remains and their remarkable
characteristics.

V. General inferences as to the conditions of the primeval
seas ; earliest appearances of vegetable and animal life; the
great fish epoch in the Devonian period ; causes of extinction ;
the igneous and trap formations and disturbances ; and the
subsequent vast development of the carboniferous flora in the
production of coal, ironstone, and limestone.

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THE TOPOGRAPHY. a

CHAPTER I.

Th ES TO POG RAP EY.

FirrsHire forms the eastern portion of the great central coal
district of Scotland. Its form is peninsular, being enclosed
on three sides by sea—the German Ocean on the east, the
firths of Forth and Tay on the south and north, and on the
west it is bounded by the shires of Perth, Kinross, and Clack-
mannan. The greatest length from east to west, along the rocky
shores of the Forth, is forty-one miles; about the centre-line
from St. Andrews to Lochleven, it is twenty-three miles; on
the northern boundary from Ferry-Port-on-Craig to Mugdrum,
near the confluence of the river Earn with the Tay, it is eighteen
miles. The breadth across the centre, in the line of Dura Den,
is fourteen miles.

Within this area there are included about 467 square miles
of land, and about six square miles of lakes. The number of
cultivated acres imperial is nearly 260,000 ; of uncultivated, in
woods and hill-pastures, about 70,000; and of under-ground
coal measures there is an area of nearly 16,000 square acres.
The county lies between 56° 2’ and 56° 27’ nN. lat., and between
2° 20’ and 3° 12’ w. long.

The general contour of Fifeshire partakes more of the gentle
and undulating outline of the downs of England than of the
bolder and more striking features which characterize the moun-
tain land of Caledonia. The Ochils, traversing its northern
boundary, and the Lomonds, running through the centre division,
separate the county into three well-defined subordinate districts,

6 MONOGRAPH OF DURA DEN.

which, as will be afterwards noticed, correspond to three equally
marked geological formations. The Ochils consist of a chain
of trap hills, extending through a course of upwards of fifty
miles, gently rising on their eastern extremity to about 400
feet, and attaining on the western, in Bencleuch and Dalmyatt,
an elevation of nearly 3000 feet above the level of the sea.
The Lomond ridge consists of an elevated table-land, about
four miles in length, completely insulated from the neighbouring
hills, with a gentle slope towards the south ; but on the north
the acclivity is precipitous and rocky, and springs from the valley
of Stratheden to the height of nine to ten hundred feet. The
east top is 1466, and the west 1721 feet above the sea-level.
Overlooking the whole county, and the two noble rivers by
which it is encompassed, with the German Ocean to the east,
the towers of Stirling and “the lofty Benlomond” to the west,
the rugged serrated outline of the Grampians to the north, and
the extensive plains of the Lothians, begirt by the Pentlands
and Lammermuirs, the Bass and Berwick-Law to the south,—
the prospect from either summit may vie with any in the king-
dom, presenting at once to the eye whatever is necessary in
water, forest, and mountain, to form the beautiful, the pictur-
esque, or the grand. Some of the objects in the immediate
vicinity give additional charm to the scene—the Palace of
Falkland, which lies at the base of the East Lomond, and Loch-
leven, which washes the sloping defiles of the west peak, and
where, in the middle of the deep blue lake, may still be observed
the ruins of the keep in which the unfortunate Mary Stuart was
imprisoned by her subjects. Standing by Cross-Macduff, in the
parish of Newburgh, the poet says, almost to the letter of the

description, —

“You do gaze—
Strangers are wont to do so—on the prospect.
Yon is the Tay, roll’d down from Highland hills,
That rests his waves, after so rude a race,
In the fair plains of Gowrie. Farther westward
Proud Stirling rises. Yonder, to the east,
Dundee—the gift of God, and fair Montrose,
And still more northward, lie the ancient towers
Of Edzell.”’

THE TOPOGRAPHY. 7

Besides the Forth and Tay, that traverse the confines of the
county, there are three rivers of considerable dimensions, as
well as of mercantile importance, which flow through the dis-
trict, and lay open in several places valuable sections of the
rocks. These are the Eden, the Leven, and the Orr. The
Eden takes its rise near the western extremity of the shire, in
the parish of Strathmiglo, and, after a course of eighteen miles,
falls into the sea at the Guard Bridge, near the Bay of St.
Andrews. The Leven issues from the loch of the same name,
and runs along the southern escarpment of the Lomonds into
the Forth, near the Bay of Largo ; and the Orr, which rises in
the coal-basin of Blair-Adam, and joining the Leven a few
miles to the north of Largo, discharge their united waters into
the bay at Leven. The lochs connected with the county are
Loch-Fitty, Loch-Gelly, Loch-Leven, Loch-Mill, the Black-
Loch, Lindores, and Kilconquhar, all of which are well stocked
with pike and perch, some of them with excellent trout. They
are frequented with various species of wild-fowl, and their
banks are adorned with tribes of flowering aquatic and crypto-
gamic plants.

MONOGRAPH OF DURA DEN.

DURA DEN.

Lines By THE Rev. Joun ANDERSON, Minister OF KiNNOULL,
AvuTHoR OF THE “ PLEASURES OF Home.”

How many pass, unthinking and unmoved,

Through scenes that wake in others noble thought—
O’er vivid footprints of the unseen God—

’Mid speaking witnesses of scheming man !

Pause, traveller! for thou treadest such a scene ;
Records of God and man surround thee here !

That Ruin, beetling o’er the rippling stream,
Where pensile wild-flowers drink the crystal wave,
And flitting flies betray the lurking trout

To the keen angler ; mark that mouldering wreck ;
‘Tis the hoar remnant of a famous pile,

Where the last Scottish Parliament convened,

And feebly grasp’d a sceptre, soon to pass

To other hands, stretch’d eagerly for power.

Note yonder hill, by far-seen pillar crown’d,
And cinctured by a zone of stately trees ;

A prouder glory rests upon its brow ;

More deathless verdure clothes its classic side ;
For there a Bard, whose name shall never die,
Sir David Lindsay, sang his Doric lay.

THE TOPOGRAPHY. 9

Dim in the distance, like the tales they tell,

St. Andrew’s sacred turrets pierce the sky—
Grey spectres standing sadly by the sea,

As if they mourn’d some ravage it had wrought.
A different sea swept o’er them —it is gone !
But these bleak fragments live to tell its fury.

Where winds the quiet, greenly-mantled dell

Into the bosom of the uplands, rich

With russet grain, or dappled o’er with flocks—
There stretch’d, in days gone by, a dreary moor—
Dreary and voiceless ; save when one wild night
It rang with ringing steel and cries of terror,

And blood, by murder shed, its heath-bloom deepen’d,
Leaving a stain no floods can wash away !

There Sharp—weak zealot of a despot-creed—
Died ; and so dying half redeemed his life.

Thus ruthless violence defeats its end,

And makes a martyr where it sought a victim !

Far up the crag, where waves the feathery fern,
And the gay foxglove hangs its purple bloom ;
Where glides the weasel on its noiseless way,

And clings the bat till evening shadows fall ;

The damp and dripping cavern wont to hide
Devoted men, who worshipp’d God by stealth,
When temples made with hands refused their praise.

These are the records, these the deeds of men ;
But other deeds and dates find record here.

Far different wrecks lie buried ‘neath your feet,
Proclaiming other changes, other times.

No billow breaks upon this sealess beach—
Nought save a tiny brook runs wimpling here ;
Yet forms of life—once sporting ’mid the waves,

10

MONOGRAPH OF DURA DEN.

Their home green ocean-caves and plains and vales—
Start from the rock at every clanging blow,

Filling the dusty workman with amaze,

And wafting back the sage’s puzzled thoughts

O’er the dusk gulf of dim, unnumber’d years !

What sea, receding from what former world,
Consign’d these tribes to stony sepulchres 4
Bewilder’d sage! proclaim thy wisdom folly,
And where thy Reason fails let Farr begin :
The rocks have sacred secrets of their own,
That teach the wise humility and praise.

GEOLOGY. 11

CHAPTER II.

GEOLOGY.

THE ORDER AND ARRANGEMENT OF THE ROCKS.

Geology informs us that there is no portion of the surface
of our planet that has not been immersed in the waters of the
deep. It is also an acknowledged principle of the science,
that there is no portion of the earth’s surface that has not
been under the influence of fire or the action of subterranean
heat. The whole superficial crust of the globe, it therefore
follows, is composed of two great systems of rocks, namely,
those which are sedimentary or stratified, and those which are
termed igneous or unstratified. All sandstones, limestones,
and shales belong to the former class ; the granites, traps, and
lavas are all ranged under the latter class. They are termed
primary, secondary, and tertiary, according to their geological
age or order of superposition.

The following table exhibits both divisions, and their sub-
divisions according to their mineral constituents, chronological
order, and relative superposition :—

Lower SECONDARY Upper SECONDARY AND
Primary Formation. Formation. TERTIARY.

Gneiss. Cambrian Schists. Trias—Red Marls, Keuper,
Mica-Schist. Silurian Schists. New Red Sandstone.
Quartz Rock. Old Red Sandstone. Oolitic—Wealden, Lias.
Limestone or Marble. Carboniferous Series. Cretaceous—Greensand,
Clay-Slate. Permian Magnesian Lime- Marls.

stone. Tertiary Series—the Hoceue,

Miocene, Pliocene, and
Pleistocene.
THE 1GNEOUS ROCKS:

Granite. Felspar Porphyry. Amyegdaloid,
Basalt. Compact Felspar. Clinkstone.
Clay-Stone. Greenstone. Tufa.

Lava.

1g MONOGRAPH OF DURA DEN.

The primary series, according to this tabular view, are by
far the most widely developed of the rock formations of the
earth. In Scotland they cover upwards of NINETEEN THOUSAND
SQUARE MILES, or about two-thirds of its superficial extent.
They prevail chiefly in the Northern Highlands; and, from
their upheaval by subterranean fires, give rise to all their
picturesque grandeur and diversified outline of mountain,
strath, loch, glen, and valley. The lower group of the second-
ary formation is, in part of the series, limited to the southern
division and border districts, and the central districts are
occupied with the old red sandstone, the coal metals, ironstone,
and limestone.

The upper secondary and tertiary formations are in Scot-
land of very limited extent, and chiefly in small patches
confined to Dumfriesshire and the Hebrides. They consti-
tute the prevailing rocks over nearly two-thirds of England,
in all the eastern, southern, and midland counties. The
igneous class of rocks again, with the exception of the
granite, all lie within the area of the coal-field, or form its
outworks, constituting the Sidlaw, Ochil, Campsie, Kilpatrick,
and Pentland ranges of hills. The Grampians, and other lofty
mountains in Arran, Skye, Ross and Sutherland shires, are
composed of granite, gneiss, mica-schist, quartz, limestone and
clay-slate.

Following the line of Section, we shall briefly notice the
relations and mineral constituents of the successive formations,
in their order of superposition, from the Grampians to Dura
Den, including a space of about twenty miles in lineal extent.

GRANITE constitutes the nucleus of the Grampian range
from shore to shore over Scotland. It is the lowest funda-
mental rock, having its seat deep in the crust of the earth ;
and it likewise forms the top of nearly all the Bens, the
loftiest mountains in the Highlands. The prevailing consti-
tuents are quartz, felspar, and mica. Where hornblende is

GEOLOGY. 13

added or substituted, as it often is, for mica, it is then denomi-
nated SrenrtrsE—the form which it assumes chiefly on the
borders of the Upper Nile, and of which many of the grandest
ruins in Egypt consist. The mica sparkles like gold, and
exists sometimes in crystals, of more than a foot square, when
it is split up into thin plates, and used as a substitute for glass.
Some granites are binary, consisting only of two minerals,
felspar with quartz or hornblende, and when polished break
into irregular lines resembling Arabic letters, on which account
it has been called graphic granite. A vein of this rock tra-
verses the district about a mile east of the town of Portsoy in
Banffshire, in connexion with mica-slate and a bed of lustrous
marble of great celebrity.

The rock which immediately overlies the granite is GNEISs,
of which there are three varieties, each composed of felspar,
quartz, and mica, and only distinguishable by the size, form,
and arrangement of the crystals that constitute the mass.
Gneiss is essentially, therefore, a granite in its component parts,
but differs from granite in being always stratified, and in pre-
senting none of the phenomena that accompany the agency of
fire. It is indisputably admitted to be of aqueous origin,
formed by precipitation in water, and afterwards indurated by
chemical action or mechanical pressure. It consists of a series
of thin lenticular plates, which give it a ribbon-like appearance,
and which, according to the predominance of one of the ingre-
dients, causes the rock to assume the slaty, granular, or
ageregate structure. Talc, hornblende, chlorite, actinolite, as
in granite, are not unfrequently diffused through the substance
of gneiss, whence particular names have been adopted to dis-
tinguish the varieties in which they occur. Thus, when tale
or chlorite is mixed in the substance, it is termed protogine
by the French geologists ; when the crystals of felspar and
quartz are very minute, the rock is named whitestone or /ep-
tinite; when the hornblende and felspar predominate, mixed
with actinolite, it graduates into a primitive greenstone ; and

14 MONOGRAPH OF DURA DEN.

when the quartz and felspar are scarcely visible from their
extreme attenuation, it merges into a variety of Hornstone.

Gneiss, the lowest of the stratified rocks, is likewise the
most widely diffused of the Scottish primary series, filling an
area of 9600 square miles, and with scarcely a break over this
extensive district of country. It occupies nearly the entire
northern counties of Sutherland, Ross, and Inverness ; great
part of Nairn, Elgin, Aberdeen, and Perth shires ; most of the
western islands, as Tiree, Coll, South and North Uist, Harris,
and Lewis, consist of the formation, as also considerable tracts
in Orkney and Shetland. While in a soft state, or from the
vast pressure to which it has been subjected, this rock often
assumes the most singular contorted appearances, whole miles
presenting twistings and undulations as if the substance had
been moved and tossed like a stormy sea, and sometimes
crumpled and bent, or rolled into gentle unbroken flexures like
a web of cloth. It will thus, in such cases, exhibit beautiful
and picturesque aspects ; and where exposed in ravines along
with other rocks, with which it finely contrasts, no better
pictures or groupings of rock scenery are to be met with.
But in general, where the gneiss is unbroken, and as it seldom
rises into peaks or serrated ridges, the districts in which it
prevails are rather monotonous and unpleasing, not unfrequently
disfigured by spongy heaths and boggy wastes. The most
desolate, uninteresting portion of the Highlands is unquestion-
ably the north-western districts of Ross and Sutherland, where
the hills of this formation are all flat and shapeless, sur-
rounded by unvarying solitudes of brown moor, interminable
deserts of sand, and scarcely enlivened by a river, or broken
in their silence by a waterfall. Gneiss is the oldest rock
known in the records of Geology—the lowest floor of the most
ancient seas—probably the first dry land that rose above their
surface ; and here, in these sterile wastes, presenting ‘a scene
of almost primitive chaos and desolation.

The next number of the series, in the ascending order, is

GEOLOGY. 45

Mica-Siate or Schist, which, as possessing more mica and
being of a more slaty structure, is so denominated. This rock
is readily distinguished from gneiss by its glistening aspect, and
from granite by the absence of felspar, although it occasionally
seems to graduate into both when in contact. The particles of
which it is composed are uniformly more broken and rounded
than those of gneiss, which probably arises from their being
partly derived from the granite and partly from the gneiss,
and have in consequence undergone a double process of
attrition. Veins of quartz, parallel with the strata or crossing
them in every direction, are so predominant often as to
change the usual colour from a glistening grey into a mottled
white. Vertical dykes of the purest quartz, sometimes
several yards in breadth, and traceable for miles along the
surface, are likewise of frequent occurrence. One variety is
termed garnet-schist, from the circumstance of these beautiful
crystals being so abundantly distributed through the substance
of the rock as to form a principal ingredient, as well as greatly to
enhance the sparkling lustre of the mica. The garnets vary from
the size of a small seed to an inch in diameter, are of a dark
crimson colour or blackish brown, and under a bright sun look
like gems in a setting of gold. They occur plentifully in the
formation near Huntly, in the upper districts of Strath Tay, and
of considerable dimension and very perfect in the Isle of Mull.

The geographical distribution of this rock is much inferior in
extent to the gneiss: it is chiefly confined to the more central
division of the Grampians, which it accompanies in one con-
tinuous envelope, along the range from sea to sea. The mica-
schist thus embraces within its course the finest and most
celebrated scenery of the Highlands. No lover of the pictur-
esque, in his most favoured haunts, can fail to recognise it,
whether by its bright metallic aspect or the remarkable flexures
into which the strata are twisted and folded up. Suffice it to
mention the beautiful ravines on the Esk and Isla, the Pass of
Killiecrankie, the Trosachs, the charming environs of Loch Ket-
terin and Loch Lomond, the precipitous defiles of Glencoe, and

16 MONOGRAPH OF DURA DEN.

the dark rugged mountains that surround Loch Goyle, Loch
Fyne, and Loch Awe. The hills of this formation are among
the loftiest and most notable in the Grampian range, rising to
4000 feet and upwards ; as Cairnwell, Ben-y-gloe, Schiehallion,
Ben Lawers, Ben Vorlich, Ben Ledi, Ben Venue, Ben Lomond,
and all the bold serrated ridges to the west. The long head-
land terminating in the Mull of Cantyre, great part of the
islands of Bute, Arran, Jura, Isla, and the whole of Colonsay,
consist of mica-slate.

QUARTZ-ROCK exists as an independent member of the series,
as well as an ingredient in every one of the primary, and of
nearly all other rocks. One set of theorists regard it as only
an altered sandstone, which, through the intense action of heat,
has been fused, and on cooling was crystallized. The more
prevailing opinion is that which ascribes it, like gneiss and
mica-schist, to precipitation in water ; but as it alternates with
both, sometimes resting on the granite, sometimes intermediate
betwixt the gneiss and schist, not unfrequently overlying the
latter, and plentifully distributed through them all, in the form
of veins and dykes, which penetrate, like the granite itself, the
whole members of the system, it is difficult to ascribe to either
view, and still more difficult to find a substitute for either
theory of formation. There are problems in every subject
which science has not yet solved. That there should be mys-
teries in geology on the formative processes of rocks, the sources
of their constituent elements, and their mode of aggregation, is
according to the rule and not the exception of speculative
inqury. The quartz-rock, thus difficult in theory to be accounted
for, has a range and position in the Grampians nearly co-exten-
sive with the mica-slate, with whose substance it is so mixed
up and forms so large a proportion.

The rock which succeeds the quartz, and sometimes alternates
with it, or is enclosed in its beds, is the PRIMARY LIMESTONE or
marble, so extensively used for ornamental purposes. This
formation consists of nearly equal parts of lime and carbonic
acid, with a trace of silica. It resembles the quartz in outward

GEOLOGY. LF

appearance, in being granular, white, and lustrous in colour, and
regularly stratified, and in hardness is scarcely distinguishable ;
but how different in its susceptibility of polish and other prac-
tical uses. Famed among the ancients in the celebrated quarries
of Paros, Pentelicus, and Carrara, their finest and most enduring
specimens of sculpture were chiselled from the same family of
rocks which claim a parentage with the limestone of the Gram-
pians. There are several varieties, differing chiefly in colour,
fineness of texture, or as containing imbedded crystals of tremo-
lite, sahlite, augite, asbestus, and steatite, whence it derives its
unctuous feel and variegated colours, as mottled, striped, and
veined by lines of pink, green, and yellow. Its range is nearly
co-extensive with that of the quartz formation, being generally
imbedded in its mass, or accompanying its outcrop. It is burnt
in a great many places into quicklime, but as the concretions
have an extreme tendency to exfoliate and separate during the
process, by the volatilization of the carbonic acid, it is difficult
to preserve its cohesive and other chemical properties, and is
accordingly not rendered so applicable to economic uses as it
otherwise might be, from the large proportion of calcareous
matter contained in it. Preserving the same line of bearing
with the quartz-rock, this limestone stretches along the more
central parts of the Grampians, and is found in almost every
position—in the bottoms of valleys, in the beds of rivers, on
the sloping acclivities of mountains, or even caping their ridges
and summits. It occurs plentifully on both sides of the Dee,
from Ballater towards the Castletown of Braemar. at which
latter place it nearly composes the beautiful hill called the
Lion’s Face, and thence passes westward by Glen Clunie and
the base of the quartz-caped Morven. Appearing at several
intervening localities, it descends Glutilt, where it is so fre-
quently penetrated by the granitic veins of Ben-y-gloe ; and,
crossing the river Garry, it may be observed high on the sides
of the green hill of Tulloch ; and spreading over the extensive
tract southwards to Loch Harn, there are various openings in
B

18 MONOGRAPH OF DURA DEN.

the strata for quarries—in Glen Tummel, Glenlyon, near Loch
Harn head, at Aberfoyle, Auchmar, Loch Lomond—when it is
again traceable through all the western isles, from Lismore to
the more quartzy regions of Jura and Isla.

The CLAY-SLATE forms a very narrow strip, of about five or
six miles in breadth, and may be described as the outer envelope
of the primary series and upper crust of the Grampian range.
It extends from Stonehaven, in a continuous belt, to Roseneath,
and through Bute to Arran, where, at Loch Ranza, it is pene-
trated by the granite, and is seen in connexion with the
mica-slate. It consists of a fine-grained argillaceous basis, of
considerable hardness, of various colours, from a greenish-black
to a deep mottled purple, and, from its splintery fissile structure,
is admirably adapted for roofing-slate. Some of the smaller
islands in the vicinity of Oban, as Luing, Hisdill, and Seil, are
composed of a different slate, chiefly the chlorite, and of older
formation. Various other bands of slate occur, in groups of
different kinds and qualities, among the primary mountains.
They are confined to no particular mineralogical district, but
are distributed at long intervals, and appear as outliers indis-
criminately in the granite, gneiss, and mica-slate series. They
are termed talc, chlorite, actinolite, and hornblende schists,
according to the prevalence of any one of these mineral sub-
stances in the mass. They have less or more an unctuous feel,
a foliated or fibrous structure, an extremely flexible texture,
and a fine glossy lustre. The chlorite schist is very abundant
in the Cairnwell and Glenshee group ; the hornblende ‘variety,
also strongly impregnated with cubical iron pyrites, occurs at
Ballahulish and Appin, and Ben Lair, in Ross-shire ; talc-slate
is not abundant, and is generally incorporated with the mica-
slate, by the substitution of the tale for the mica plates. Acti-
nolite schist is usually associated with, as it differs little in
character from gneiss and some specimens of granite, and is
found in considerable quantity in Glenelg, and the high and
beautifully sloping passes of Glen Shiel.

GEOLOGY. 19

After this brief description of the primary rocks, it only
remains to be noticed, in connexion with the adopted theory
of their formation, that in proportion to their relative distances
from the fundamental granite, the greater is the comminution
of their particles, and the less crystalline their structure.
Assuming the igneous origin of granite, it necessarily follows
that its surface, penetrating the waters of the primitive seas,
would be subject to the disintegrating influence of atmospheric,
aqueous, and chemical agencies. The waters themselves,
especially when resting in the newly-formed hollows, must
have been heated to a high degree, the air loaded with
vapours, and the superficies of the earth raised to a corre-
sponding temperature. The process of disintegration would
consequently be much accelerated. The runnels and streams
would carry down the loose particles, disposing the heavier
portions first and nearest, and bearing the lighter and smaller
to deeper basins. Hence there exists the greatest affinity
betwixt these rocks, where, according to the law of their
ageregation, the granite is sometimes fused into the gneiss,
the gneiss into the mica-schist, and the quartz rock, marble,
and other beds all welded into each other ; and thus strongly
warranting the inference, that the whole series have been
exposed to the action of heat after the deposition and arrange-
ment of their component parts.

Heat alone, of all known causes, could produce such results.
Added to the phenomena of veins—in the changes, dislocation,
and induration invariably produced upon the strata through
which they pass—there are few dogmas of science that can
boast of resting upon a wider induction of facts, than that the
mountains of the earth owe their elevation to the expansive
force of internal fire, and that its massive foundations have been
consolidated through the instrumentality of the same agent.

The rudiments of all the rocks and after-formations are
thus re-compounded only from the waste and debris of the
originally solid parts, or have been cast out from beneath by the

20 MONOGRAPH OF DURA DEN.

influence of the causes which produced their elevation. The
quartz of the granite constitutes the substance of some of the
more precious gems ; the mica is divisible into plates of the
three hundred-thousandth part of an inch in thickness, and
enters as an ingredient into almost every combination of rock ;
the felspar is reduced to clay, and, mixed with the hornblende,
forms the soil of our most fertile carses. Here also among the
primary series—wherever existing on the globe—is the vein of
the silver and the gold and all the rare metals, and the
emerald, sapphire, beryl, topaz, and amethyst all nestle in their
crystal cavities. The marble to decorate our temples, the
slates to furnish a commodious roofing to our dwellings, the
granite to give endurance to our monuments, are among the
first of Nature’s offerings ; and thus combining security and
elegance, usefulness and beauty, richness and variety, the foun-
dations of our steadfast earth, and arrangement of its mineral
wealth, are well calculated to speak the praises of its muni-
ficent Creator, and to form a noble subject of contemplation to
its intelligent inhabitants.

The primary series of rocks now described are followed, as
represented on the Section, by a COARSE CONGLOMERATE of
great depth and extent (6). Grey and red fine-grained sand-
stones rest unconformably upon this mass, intermixed every
where with outbursts of trap or the igneous rocks (fed c x).

The large boulder conglomerates of Caithness, Sutherland,
and Orkney, first described in the conjoint papers of Murchison
and Sedgwick, and recently so admirably worked out in all
their bearings in the appendix of the new edition of Silduria,
may be considered as the true equivalents, in age and position,
of the great conglomerate masses that flank the southern out-
liers of the Grampians. These rocks contain large portions of
all the primary series, rolled as well as angular, some of which
are eight or ten feet in diameter. They are deeply cut, and
beautifully exposed to view, by the wearing channels of the

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22 MONOGRAPH OF DURA DEN.

rivers Esks, the Isla, the Ericht, the Brand, the Tay, the Earn,
and other mountain-streams that leap from Glen-Artney and
precipitous passes to the westward. Good sections of this
formation have been exposed on the Dunkeld line of railway,
under Birnam hill ; the main drive of the newly-formed
aqueduct from Loch Vennachar to Glasgow intersects the
conglomerate, where it is elevated in many places into lofty
ridges of several hundred feet in height ; and, at intervals, it
is traceable along the shores of the Clyde, and largely developed
_ in the islands of Bute, the Cumbrays, and Arran.

A series of grey sandstones of great thickness succeed the
conglomerate, resting unconformably upon its more inclined
edges (gh). These correspond in age and position with the
Caithness fossiliferous flagstones, while several of the beds are
wanting, especially those so rich in the coccosteus, paleoniscus,
and cheirolepis families. They range over the Mearns, Strath-
more, and Forfarshire ; occupy the central and upper districts
of Strathearn from Comrie to Doune ; and, easterly, traverse
the Carse of Gowrie and estuary of the Tay to Dundee and
Arbroath. The celebrated fossiliferous deposits of Balruddery,
Carmylie, Tealing, Craig, and Parkhill are all embraced within
the area now traced of these grey sandstones, some of which
are extremely fissile and flaggy in their beds, and others more
gritty and micaceous in their characters.

The strata all dip off from the Grampians, generally in a
south-easterly direction, and at various degrees of inclination.
The thickness of the group may be estimated at about 2000
feet. The deepest section is exposed in the quarries of Bal-
beuchlie ; and the beds, uptilted at various angles, proceed ~
along the ridges and numerous valleys of the highest crest
of the Sidlaws. ‘There are in the line of strike from north to
south, two well-defined synclines and three antzclines, occa-
sioned by the upheaval of the trappean formations.

The suite of sandstones under consideration are extremely
rich in organic remains, consisting of cephalaspis, pterogotus,

GEOLOGY. 23

various forms of crustacea altogether unknown in zoology,
Parka decipiens, stems of trees, and several kinds of marine
and fluviatile vegetables. A space of rock, about ten feet
square, was lately cleared in the presence of the author, every
patch of which contained fossil markings of some kind or
other ; and on one portion of flagstone now before me, seven
inches by five, I enumerate about eighty distinct impressions
of the Parka decipiens, or egg-sac of the pterogotus. The
locality is the Coral Den of Tealing, new to collectors, and the
habitat of a complete form of Pterogotus Anglicus, now in the
Watt Institution of Dundee, and rivalling even the splendid
specimen from Balruddery, in the collection of Lord Kinnaird
at Rossie Priory. Besides several specimens of pterogotus,
with their huge prehensile claws and swimming paddles, and
scale-like sculptured segments, which often indicate individuals
five and six feet in length, “ We have,” says Mr. Page, “the
ceratiocaris, a shrimp-like form (ceratiwm, a pod, caris, a
shrimp), so called from the pod-like shape of its cephalic
shield ; the kampecaris, a diminutive form (kampé, a grub or
caterpillar), named from its caterpillar-like appearance, and
occurring in shoals in the Forfarshire flags ; the cumoid forms
found so abundantly in the mud-stones of Upper Lanark, and
which may be provisionally ranked as new genera, under the
titles Himantopterus (thong-winged) and Stlimonia (after their
discoverer, Mr. Slimon) ; and, more recently, the quaint-looking
Stylonurus Powriensis, obtained by Mr. Powrie from the tile-
stones of Forfar, and so named from the peculiar style-like
form of its caudal appendage. All these, and other forms yet
undescribed, are totally new to science, are here * for the
first time figured, and open up a fresh and inviting field to
the crustaceologist.”

In addition to the remarkable list of organisms thus enu-
merated, there are spines and other osseous fragments in the
greatest profusion—teeth, jaws, and foot-like markings. The

* Advanced Text-Book, p. 135.

24 MONOGRAPH OF DURA DEN.

spine forms are in many places so numerous that the surface
of the rock is literally covered with them ; the white spear-
like projections contrasting strongly with the fucoid masses in
which they are entangled. The plant remains are no less
abundant, consisting of stems and branches of trees, and tufts
of water-grasses thickly matted together. The stems are
generally flattened; often three to four inches broad ; but
the bark is so changed by carbonization as to render the
application of the microscope of little use. The sedge-like
grasses (juncites) are slender and jointed, and sometimes
several feet in length. Over large areas, and for miles east
and west, in every opening of the tilestone bands, the surface
of the rock is entirely blackened by these and the other
organisms, clearly demonstrating a quiet inland shore-line or
marshy lagoon, over which much of the detritus may have
been cast by the action of the tides, and in the silt of which
several of the grasses may have flourished zn sztu. Thither
would roam the pterogotus, cephalaspis, and other fishes and
crustaceans in quest of food, so plentifully supplied by the
shrimps, grubs, and other small creatures that lived in the
shallows, or there sought a fitting place for the deposition of
their spawn among the sea-weeds of the period.

Resting upon these grey sandstones—the true zone of the
cephalaspis and pterogotus—Red Bands of rock succeed (i &) ;
and in the lower basin of the Tay and Harn, they consist of three
varieties—a fine-grained, a compact gritty, and a conglomerate.
The Clashbennie beds may be taken as the type or representa-
tive of the first; they are always unconformable to the grey
sandstones, when seen in conjunction, as in Rossieden and
Balruddery, Parkhill and Wormit Bay. This, and the upper
series of Dura Den, may be considered as constituting the true
zone of the genus holoptychius, which now for the first time
appears in the ascending order of the rocks, along with the
phyllolepis and glyptolepis, whose scales are very abundant in
Clashbennie, Parkhill, and Drumdreel in Stratheden.

GEOLOGY. 25

The same series of sandstones as those now described extend
into Fifeshire, skirting the south bank of the Tay, and reposing
on the northern slope of the Ochil Hills from Ferry-Port-on-
Craig to Newburgh. The grey bands are the lowest, and cor-
respond in geological age and horizon with the cephalaspis and
pterogotus beds of Balruddery and Carmylie, although they rise
on Norman’s Law to an elevation of nearly eight hundred
feet. No animal remains have as yet been detected in the
grey beds of Fifeshire, but the Parka decipiens is everywhere
abundant. This rock stretches over the parish of Balmerino
into the valleys of Kilmany, rising on the ridges to the south,
and dipping under the red deposits which extend into Dura
Den on an anticlinal axis (¢ 4).

The red-coloured series consists of three distinct varieties,
the conglomerate, the fine-grained, and the yellow spotted,
which, however, are regularly associated, sometimes separated
from each other by bands of clay and marl, and sometimes
passing insensibly into one another without any perceptible line
of demarcation between them. ‘This division of our lithology,
as marked on the line of section, extends from the Grampians
to the opening of Dura Den at the church of Dairsie. In
Strathmore, to the north of the Sidlaws, the outcrop of the
series may be observed in several places, as from Meigle to
Blairgowrie, and along the channel of the Tay from the Bridge
of Isla to Stanley.

The conglomerate is the lowest of the series, lying incon-
formably on the grey bands beneath, and consists, like the older
and coarser variety, of portions of the primary rocks, granite,
gneiss, schist, quartz, porphyry, and hornblende. They are in
the form of rounded nodules, or sometimes of blunt angular
fragments, varying from an inch to six inches in diameter.
The interstices between the nodular masses are composed of
smaller portions of similar materials, and possess a considerable
degree of cohesion. The compact variety rests conformably
above the conglomerate, and so intimately connected are they,

26 MONOGRAPH OF DURA DEN.

that, in raising a block from the quarry, they are generally
attached ; the nodules in the lower bed perforate the more
compact substance of the upper, and lead to the conclusion that
they are contemporaneous deposits, and were produced under
the same circumstances, the heavier portions assuming their
position in the bed according to their specific gravity. The
fine-grained is uppermost, is generally of a deeper red, and
contains more argillaceous matter than the other two ; the mica
is also more abundantly distributed in minute grains through
the rock.

Spots of a round spherical form, and of a yellow colour, are
common to all the beds, but are most numerous, as well as of
larger dimensions, in the upper. In some localities the spots
are so abundant as to cover more than a third of the surface,
and vary from the minutest points to nearly a foot in diameter.
A section of the spot across the plane of stratification is
uniformly circular, but when cut at right angles the figure is
invariably spherical, with a dark-coloured nucleus in the centre,
which is occasioned, in all probability, by the discharging influ-
ence of animal matter. One thing is certain, that portions of
scales and minute bones have been detected in the centre of
the spots. Of this I have several specimens from Parkhill and
Inchture, which distinctly show the animal matter in the act
of solution as it were, and thereby staining the matrix in the
manner referred to; while in a period so prolific in all kinds
of marine products, animal and vegetable, innumerable organic
particles would be everywhere floating in the waters, and
finally enveloped among the mineral deposits. The best
specimens of this rock are to be found at Inchture and
Ballindean in the Carse of Gowrie, and at Birkhill, the Glen
of Abernethy, and Drumdreel in Fifeshire, stretching eastward
through Stratheden in the line of Dura Den towards the
Guard Bridge.

The extent and direction of these red sandstones may be
briefly traced. On the eastern coast the deposits commence

GEOLOGY. 27

near Stonehaven in Kincardineshire, and, extending across the
Bay of St. Andrews, skirt the slope of the Ochils towards the
river Eden. They trend in a westerly direction by Dura Den,
the base of the Lomonds, and stretching on the east and north
of Kinross, through the parishes of Strathmiglo, Arngask, and
Orwell, they occupy the valley from Dollar to Stirling ; thence
by the northern flank of the Campsie Hills towards Loch Lomond
and the basin of the Clyde. The materials of which these beds
have been formed have unquestionably been derived from the
debris of the older primary formations, by which they are
encompassed north and south of the Grampian range, and in
many of the lateral glens and valleys, as in a setting of parti-
coloured framework. The Grampians were, in all probability,
elevated before a particle of these sandstones was yet dis-
integrated from its parent rock ; while the Sidlaws and Ochils
were raised into position in ages long after, when these sedi-
mentary deposits formed the banks and tidal detritus of
estuaries and rivers that now have no place in the geography
of the earth.

The Cornstone, or Limestone, is the next member of the
series in the ascending order of superposition. It occurs
at various places throughout the county, as Craigfoodie,
Newton of Auchtermuchty, Parkhill, Clatchart, Newburgh,
aud Clunie. At Craigfoodie it appears as an outlier or
mere patch among the trap; it presents a similar aspect
at Newburgh station, on the line of railway, and trending in
among the rocks to the west it is scarcely distinguishable
from the igneous mass; while at Newton the limestone has
been tossed up to the summit of the Ochils. At Parkhill
it reposes conformably upon the Old Red sandstone, and con-
sists of four beds separated from one another by brown and
greenish-red marl, traversed by veins of crystallized carbonate
of lime. The lowest bed is five feet thick, the second is two
feet, the third is about nine inches, and the upper bed is four
feet thick. This bed is more arenaceous than any of the rest,

28 MONOGRAFH OF DURA DEN.

and seems to pass insensibly into a yellow-coloured sandstone,
some blocks of which, indeed, are scarcely to be distinguished
from that rock. The position of the cornstone, therefore,
appears distinctly to be betwixt the red and yellow sandstones ;
and, accordingly, at Craigfoodie, although tilted out of its natural
position by the trap, it lies in the near vicinity of the yellow
beds of Dura Den.

The cornstone, a little to the south of Parkhill, is curi-
ously tossed up under the western slope of Clatchart, over-
roofed by a mass of clinkstone trap of 200 feet thick, and
underlaid by the grey sandstone, which, again, is intermixed
with the trap whose point of contact exhibits their fusion into
each other. The cornstone and sandstone are pitched up
at an angle of twenty-three degrees, and the accompanying
marl-beds, wasted away, show the lines of stratification in beau-
tiful relief. There is a greenstone dyke a few hundred yards
to the west, which crosses the ridge south and north, and clearly
manifests itself as the lever-power which has elevated the whole
huge mass of Clatchart, with its overhanging cliffs and sedi-
mentary foundations of lime and sandstone.

This limestone is hard, compact, and sub-crystalline, and gene-
rally of a yellowish-green or grey colour. The structure is
concretionary ; some portions of it are cherty, containing chal-
cedonic veins and small globular cells, which are coated over
with mammillated reddish chalcedony ; but generally it may
be described as a compact concretionary deposit, with several
interposed beds of a green and red pyritous marl, and stained
on the surface with innumerable dentritic figures. At Newton
it assumes the appearance of a calcareous breccia, containing
nodules of chert and jasper ; while two miles to the north-east,
on the property of Clunie in Strathearn, it is of a soft friable
nature, known in the neighbourhood as “the marl pit,” and
long used as such for agricultural purposes. No organic re-
mains have been detected in any of its numerous localities,
and the rock is nowhere observable but in very limited por-

GEOLOGY. 29

tions, feathering out and in among the sandstones and traps
throughout the estuaries of the Tay and Earn, in the Carse
of Gowrie, and over the range of Strathmore to the line of the
Grampians.

The yellow sandstone occurs as the next overlying rock in the
ascending series, commencing on the western side of Dura Den
(m) on the banks of the river Eden, and stretching southwards
about a mile to the middle of the ravine, where it abuts
against a trap dyke, which separates the Devonian from the
Carboniferous strata. On the eastern side, at the entrance to
the Den, the rock is wasted away by the action of the waters,
which leaves a large open space, where the underlying red
member of the series is exposed to view. The deposit occupies
the valley of Stratheden, and ranges under the Carboniferous
cliffs of Nydie, Blebo, Cults, the Lomonds, Binarty, the Cleish
and Saline hills, and in great part of this range the two sys-
tems are separated by masses of greenstone trap. At the
northern opening of the Den the rock reposes unconformably
on the underlying red beds, which are here of identical colour
and mineral texture with those of Clashbennie, and character-
ized by similar white-stained large scales of the Holoptychius
nobilissimus. The lower beds of the Carboniferous series, of
ereat thickness, rise again over the yellow beds towards the
southern opening of the ravine, which are likewise uncon-
formable, and maintain the same relative unconformable super-
position through the entire range, as already described, except
where disturbed by the intervention of the igneous rocks.
Thus enclosed between these two well-marked and distinctly
separated systems, the intermediate lying beds of the yellow
deposit of Dura Den present facilities for study which are
seldom to be met with, unmistakably define the limits and
the relations of their respective systems in the geological
calendar, and from their rich and varied fossiliferous remains,
justly entitled to be classed with that remarkable series of

30 MONOGRAPH OF DURA DEN.

rocks which constitute the fish epoch, and of which the Old
Red sandstone forms the true distinguishing type.

The yellow sandstone reappears in the western districts of
Scotland, at Kilbarchan in Renfrew, at Girvan in Ayrshire,
and, across the Channel, in Ireland, at Cultra in Down, and at
Ballinascreen in Derry. The deposit maintains throughout the
same relative position to the underlying red and superincumbent
strata of the coal-field. It is marked by the same mineralogical
peculiarities of structure, and distinguished by similar organic
remains. Hence, like all the great leading Scottish formations,
it extends persistently across the island, concealed in the more
central localities by the traps and carboniferous sandstones, but
everywhere maintaining its deep saffron tinge and variegated
mottled bands of red shales and concretionary marls. Pterich-
thys major is abundant in the upper Old Red of the “ Heads
of Ayr ;’ and Holoptychius nobilissimus abounds, along with
Cyclopteris Hibernicus, in Prestonhaugh quarry, near Dunse.

The deposit, along the tract now indicated, may be esti-
mated at four to five hundred feet in thickness, and varies
from half a mile to a mile in average breadth. The inclination
of the beds is various. North of Cupar, as seen in the Lady-
burn, the dip is about an angle of 20°; at Cuparmuir quarry
and at Hospital-mill it is at an angle of 16°; while in Dura
Den, Drumdryan, Glenvale, and other localities to the west-
ward on the farm of Lappa, the inclination is generally from
10° to 6°. The rise, or outcrop of the strata, is towards the
north, on the slope of the Ochils, and the dip to the south-
east. From Cults-hill westwards to the base of the Hast
Lomond, the strata have been thrown down several hundred
feet by a series of faults which occur there ; from this point
they are again elevated, when the yellow sandstone may be
observed along the ‘northern escarpment of the Lomonds,
reposing upon the red beds of Drumdreel and Urquhart,
where they are cut and abraded into large tabular masses, and

grooved in many places by glacial action.

GEOLOGY. ol

The organic remains of this interesting deposit have as yet
only been found on the western side of the Den, where the
strata are abruptly cut off by the greenstone trap referred to ;
but, in following out the dip to the eastward, little doubt can be
entertained of their equally rich distribution in that quarter.
The rock there attains its greatest depth and elevation, show-
ing a breast of several hundred feet of variegated marls and
sandstone (see Vignette). It is here, at the bend occupied by the
mills, that the structure of the rocks and the perspective of the
valley are seen to the greatest advantage—the deep-tinged
yellow masses and mottled stripes rising overhead, enlivened
and beautifully diversified by running streams, leaping water-
falls, and tangled thickets of the bracken and milk-white thorn.
The hand of art, in cutting the precipitous face of rock, has
greatly enriched the scene, and given facilities to the geologist
in admitting him to the richest and finest tract of fossil re-
mains that ever gladdened his eyes or adorned his cabinet.

It is a lovely place, and at the side

Rises a mountain-rock in rugged pride,

And in that rock are shapes of shells, and forms
Of creatures in old worlds. .

But no! the shells are not in the yellow sandstone. They are
nevertheless in the nearest vicinity, and in the mountain lime-
stone of the neighbouring coal-field they exist in countless
myriads. Dura Den exhibits, in the closest juxtaposition, the
wonders of the two geologic ages. A step carries you from
the one series of rocks to the other ; and, leaping across the
stream, in this ‘arrow dell, you pass the shadowy bourne
which separates two of the oldest and most singular epochs in
the world’s history. The epoch of fishes of the most remark-
able characters—the shining enamelled ganoid class—is_ suc-
ceeded by the epoch of vegetables, all nearly of tropical climes,
of the most exuberant growth and affluent abundance. The
mighty operations are marked here on a small scale, though
recorded in the most legible characters. A slight depression

on MONOGRAPH OF DURA DEN.

in the dip of the strata on the one side ; a few black lines
interspersed among stripes of white on the other side ; and
this is the simple lithograph by which nature tells of energies
whose products are mountains and valleys, new teeming lands |
of forest wealth, seas swarming with the moving things that
have life, and mineral treasures enclosed for man’s use which
time only can exhaust.

The northern line of the Carboniferous system—the lip of
the great coal-basin in Scotland—lies within the valley of Dura
Den. It is distinguished by three or four thin seams of coal,
with alternating bands of whitish sandstone, and all much
broken, indurated, and upheaved by an outburst of greenstone
trap. At the point of junction (p x) the sandstone is converted
into chert, and in several places so welded to the igneous rock
as scarcely to be disjoined by the stroke of the hammer. In
the more southern part of the Den, the trap repeatedly alter-
nates with the sandstone, which is there of great thickness,
and thin bands of ironstone, shale, coal, and limestone begin to
appear as the harbingers of the true coal series in the Ceres
basin. There the beds of coal are of great thickness, the main
seam being sixteen feet ; and the limestone is equally remark-
able for its vast profusion of animal remains, some of the
bands at Teases, Craighall, and Drumcarro being an aggrega-
tion of encrinites, producti, and other molluscs. The Mytilus
alone forms a band of shale of several feet thick, extending
from the West Lomond to the Witch Lake at St. Andrews, in
nearly one continuous mass of dark-coloured shells.

The mountain limestone defines throughout the district
the limits and outcrop of the true series of coal-metals.
All the beds beneath are of little value as combustibles, and
unremunerative in the working; those above this calcareous
mass are extremely rich in quality, and amount upon an
average to fifteen workable seams of coal, while in the Dysart
basin they are thirty-three in number, and some of them of

GEOLOGY. aaa

great thickness. The yellow sandstone is the clear and certain
line of demarcation along the northern verge of the under-
coal series. And as if to render that line still more definite,
the truncated edges of every member of the series are severally
brought to the surface along the elevated ridge to the east and
west. Thus, at St. Andrews, the beds are all exposed to view
by the action of the waves, under the line of the Castle rock
and the Witch Lake, where they amount to twenty-two in
number, and to about 150 feet in aggregate thickness. The
Lomond acclivities display the relative position of the two
classes of rocks in the same distinct manner, where the beds
can be counted individually, from the mountain encrinital
limestone to the yellow sandstone of Glenvale and Urquhart ;
and along the Cleish, Saline, and Dollar hills there is every-
where a favourable opportunity of examining in detail the
several members of the group.

As it is not my intention to go into details in this memoir
of Dura Den and its relative rocks, suffice it to state that
Fifeshire contains an epitome of the Carboniferous system,
divided into numerous local basins, and everywhere character-
ized by the boundary lines of the lower and older formations.
The eruptive rocks, within the area of the coal-field, are here
also to be studied to great advantage, where they have played
no insignificant part in giving shape and outline to the landscape,
- and in laying open the enclosed treasures. It were indeed
impossible to convey an adequate idea, in mere description, of
the marvellous display of plutonic action of which the dis-
trict around has been the theatre ; subterranean movements
crushing and grinding into fragments the solid strata, parting
and heaving them like forest leaves asunder, or crumpling into
complicated folds the tougher and more unyielding beds, like
some fabric of manufacture tossed and twisted by the wind.
The storm lifts the ocean into lofty curling billows, leaving
long narrow troughs and frightful yawning chasms beneath.
Here, in like manner, and all over the surface, the crust has

C

o+ > MONOGRAPH OF DURA DEN.

been broken up, and the minerals tossed about or agitated like
wreck upon the waves, and subsiding, have been cast into the
form of ridges, or of broad tabular masses. The ridges, with
their broken edges in the interior of the county, have been
gradually rounded off, and are now covered with soil ; while
along the shores they still present the effects of the violent
commotions to which they have been subjected—exposed and
laid bare by the action of the sea upon the lower levels of the
disrupted strata.

Hence the coal-metals were at once indurated, and shared in
the general elevation of the trap-hills, where they are either
folded round their bases, or are depending, drapery-wise, from
the sides. The lowest of the beds in the under series are raised
about a thousand feet along the Lomond ridge, encompassing
the east and west cones ; and Largo and Kelly Laws have each
their coal-basins, of workable minerals, stretched along their
eminences, while on the low grounds which skirt them on the
south, the metals are collected in various independent hollows
by the shore, and dip rapidly into the estuary of the Forth.
Fifeshire thus owes its diversified shape and contour, and easy
access to all its vast mineral treasures, to the early disturbances
by which it has been all over dislocated and furrowed. Every
district has a section, separate and independent, of its own ;
sweetly pastoral in its uplands; richly alluvial in its straths
and valleys ; deeply loamy in its hollows and _ hill-sides ; pre-
eminently fertile in its agricultural conditions ; and in its
mineral stores of lime, iron, and coal, not surpassed in amount
and value by any proportional area on the surface of the
globe.

The only other noticeable point connected with the struc-
tural arrangements of Dura Den, is a vein of galena or sulphu-
ret of lead, which occurs on the farm of Myretown of Blebo,
and which runs across the strata from nearly south to north.
Its discovery was made in the year 1722—a year of disastrous
gold-hunting and ill-devised mining researches throughout

GEOLOGY. oD

Scotland—-by large outliers and masses of ore found on the
surface of the ground. Some of these are described as weigh-
ing from ten to twenty-four stones in weight. A vein was
opened about two feet thick, and gradually decreased from
seven to about three inches, when, by the disturbed and rup-
tured state of the strata, and frequent intrusion of the trap,
the operations were abandoned as being unremunerative. The
shaft, which is still open, was carried through the trappean
rock ; and thus the position of the vein gives probability to
the theory that the igneous agency which forced upward the
trap, produced also by sublimation the ore which is found
enclosed within its mass or near vicinity.

Trap Dykes, composed of concretionary greenstone and
basalt, occur frequently in the neighbourhood, and, indeed, are
everywhere distributed over the coal-basin. They range in all
directions, rising perpendicularly through the stratified rocks,
and often stand several feet above the strata, like a wall
rudely piled up by Cyclopean builders. The adjacent strata
in the line of their direction are generally altered in position,
upheayed or thrown down by faults, and their structural char-
acters are much changed. The coal for some distance is
calcined and valueless ; the limestone near them will not burn
into quick-lime ; and the shales and sandstones are hardened
and chertified. The transference of mineral qualities is likewise
remarkable in the intruding trap itself, which at the point of
contact becomes more or less calcareous and siliceous—often
coated with iron, and enclosing portions of coal or carbon.
These changes resulted clearly from the igneous agency, which
by its upward pressure severed the superincumbent mass of
stratified rocks, and then poured like molten lead its subterra-
nean materials into the fissures. Once observed in any district,
these natural dykes are of too marked a character not to excite
inquiries, in every intelligent observer, as to their uses and
mode of formation ; and occurring, as they do, in every region,

36 MONOGRAPH OF DURA DEN.

and among all classes of rocks, from the oldest primary to the
newest tertiary, they are obviously designed to subserve some
grand purpose in the plan of creation.

The coal measures are likewise intersected by faults or
fractures, the fissures occasioned by which are usually filled
with clay and debris of the surrounding rocks. They may be
considered as so many excellent mechanical contrivances, by
means of which the useful mineral has been rendered accessible
to man. Had they not existed, the pits must have speedily
filled with water, or the water have accumulated in such quan-
tities as to have exceeded all power of machinery in effecting
the drainage of a mine; whereas, by the natural arrangement
of a system of faults, the continuous beds of shale and sand-
stone, alternating with the coal, are broken up into limited
sections, and the water percolates in limited quantities. The
component strata are thus divided into insulated masses, rising
one above another in the form of a stair, and inclined at a
considerable angle to the horizon ; so that, while each section
is separated from the adjacent beds by a mass of clay imper-
vious to water, the limited extent which it occupies, and the
inclined position into which it has been thrown, serve to render
the operations of the miner comparatively easy, as well as
greatly to diminish the expenses of excavating the mineral.

The first appearance of the coal deposit in Dura Den fur-
nishes a beautiful example of these remarkable phenomena in
the action of both dykes and faults. Three beds of coal, with
their enclosing shales and sandstones, are severally lifted from
their original horizontal position, elevated to an angle of forty-
two degrees—some of them to the perpendicular—are again
shifted downwards, and finally replaced in the most perfect
horizontality towards the upper part of the Den. There are
several repetitions of similar dislocations, upheavals, and de-
pressions, as the coal metals rise southwards to Largo-ward,
there attaining an elevation of 600 feet above the level of Dura
Den, and even higher in the coal basin of Rires on the sloping

GEOLOGY. ST

sides of Largo Law. The general contour of the district is that
of a series of ridges, with alternating hollows, all the result of
corresponding disturbance in the rocky masses beneath, and all
so arranged internally by a wise Providence, as at once to
impart beauty and variety to the landscape, and to render the
enclosed treasures of coal, lime, and iron most subservient to
the use and comfort of man.

The several systems or formations of rocks thus briefly
glanced at, when studied on the great scale, are all of the easiest
access for observation, and are all separated by well-marked
physical distinctions. Approached from the north, as we have
done, they all lie face to face with the observer, trending from
east to west, and successively protruding in regular serial order
from below upwards. The courses of a building are not better
defined, nor the colours of a picture more clearly delineated,
and every rock in its due place of superposition stretches across
the mainland from sea to sea. In no district are any of the
members of the series, primary or secondary, covered up or
entirely concealed from view. Where the continuity is broken
by straths, rivers, or arms of the sea, or, as often occurs, by the
eruptive rocks, the formation can again be traced out with little
difficulty on the opposite sides. This arrangement, more espe-
cially with all the divisions of the Old Red, is uniformly persistent,
and as nearly as possible according to lineal perspective. From
the blue slates of the Grampians to the variegated sandstones
of Dura Den, there is a continuous succession of ascending
layers of rock, lying with their out-crops tilted one above
another, chapter after chapter of the world’s history stereotyped
on their stony tablets, and the families of its earliest annals, in
countless numbers of vegetable and animal forms, preserved for
the inspection of all who will read the instructive pages.

Sir R. I. Murchison, in the course of last year, went over the
whole of the district now described, and in the concluding

38 MONOGRAPH OF DURA DEN.

chapter of Stluria, after stating that the oldest known rocks of
the British Isles are composed of a highly crystalline, horn-
blendic gneiss, with powerful granite veins, and that in the
North Highlands of Scotland there is from that rock an ascend-
ing order in proceeding from north-west to south-east, proceeds
to observe “that the conglomerates and sandstones which in
the North-eastern Highlands form the base of this series, are
compounded out of all the pre-existing rocks above described,
whether gneiss, older grits, quartz rock, mica-schist, granite,
&c., as ranging in ascending order from the west to the east
coast. It is this great and thick lower zone of the Old Red of
the Northern Highlands which I consider to be equivalents zn
time of those beds on the eastern and southern flanks of the
yrampians,—Arbroath, Dundee, and Balruddery,—and which,
unquestionably, constitute the base of the group, as demon-
strated in England by their conformable union downward with
the true Ludlow rocks or uppermost Silurian.”

“The true base,” continues Sir Roderick, “in Shropshire and
Herefordshire of the old red sandstone, properly so called, is, I
repeat, seen to be a red rock, containing cephalaspis and pter-
aspis, and gradually passing down into the grey Ludlow rock ;
and in both of these contiguous and united strata, remains of
large pterygoti are found, but of different species in the two
bands. Now, although the Arbroath paving-stone, and the
erey rocks ranging to the north of Dundee, much resemble the
uppermost Ludlow rock, they contain the Cephalaspis Lyellia,
with another kindred species, and are therefore to be classed
with the Devonian rocks, though they must, under every cir-
cumstance, be viewed as the very base of that natural group.
It follows, therefore, that, if the great lower conglomerates on
the flanks of the Grampians really underlie all those grey rocks
with pterygoti, cephalaspides, and Parka decipiens, they can no
longer be united as they have been with the Old Red or Devo-
nian, but must represent some portion of the Silurian system.

“ Lastly, I visited Dura Den, in Fifeshire, in the company of

GHOLOGY. 39

Lord Kinnaird and the. Rev. Dr. John Anderson, whose able
work on that beautiful tract is well known to geologists, and
now I entertain no doubt whatever, that the yellow sandstones
with red layers pertain truly to the Old Red group, that they
are entirely subjacent to the equally yellow carboniferous sand-
stones with coal plants, and are of about the same age as the
yellow sandstones of Elgin. A splendid specimen of the genus
holoptychius, three feet long, was found on the occasion of this
visit, on the property of Mrs. Dalgleish ; and as a form very
similar abounds also in the lower red portions of the deposit at
Clashbennie, the age of the yellow sandstone is clearly substan-
tiated. . . . Dr. Anderson is now convinced that this splendid
Specimen, now in the collection at Rossie Priory, is truly the
Holoptychius Anderson. of Agassiz.

“ He further informs me that the yellow sandstones of Dura
Den contain ichthyolites of the genera Platygnathus, Diplo-
pterus, Glyptopomus, Holoptychius, Pterichthys (Pamphractus),
with a new genus, an assemblage which shows that certain
genera range from the Caithness flags, or central portion of
the Old Red group, up into its highest zone. Dr. Anderson’s
finest specimens are in the British Museum.” *

Homocereal. Heterocercal.

* Siluria, Third Edition, pp. 553, 556, 559, 574.

40 MONOGRAPH OF DURA DEN.

CHAPTER IIL
HISTORY OF THE FOSSIL REMAINS.

THESE comprise several distinct genera as well as species of
their different families. There is one belonging to the order of
crustacea, and the rest are of the type of true fishes. Some of
the genera are entirely new to science, and some are new
species, whose generic forms have been found in other localities.
The remains of these fishes are so very abundant in the yellow
sandstone deposit of Dura Den, that a space of little more than
three square yards, as already noticed, when the writer was
present, yielded about a THOUSAND fishes, most of them
perfect in their outline, the scales and fins quite entire, and
the forms of the creatures often starting freely out of their
hard stony matrix in their complete armature of scale, fin,
and bone.

This peculiarity of entireness, and even of freshness in these
olden denizens of the waters, is so remarkable that, when first
exposed to view on the newly split-up rock, there is a life-like
glistering over the clear, shining, scaly forms, that one can
scarcely divest himself of the idea, instead of the innumerable
series of geologic terms to be counted, he is looking actually
upon the creations of yesterday, the relics of things that had
just ceased to breathe. “ Here is a living one!” exclaimed a
workman, as he raised from the bed of the river a large flag-
stone on which were counted upwards of fifty fishes, one pre-

HISTORY OF THE FOSSIL REMAINS. 4]

eminently beautiful, full, and rounded in its form. Indeed, the
most splendid representations of an Audubon, a Gould, or a
Landseer, on their glossy canvas, will shrink in comparison
beside these pictures of nature-painting, brighter than the dyes
of the artist as set in their stony tablets, and contrasting
finely with the rich saffron-coloured rock in which, uninjured
and unstained, they have hung for ages.

Here, doubtless, were inlets to deep waters, and projecting
creeks, and oozy sandbanks, and currents with their affluents,
and arrangements of seas, lakes, and lands now all utterly
obliterated. The sands are piled up into thick-set rocks of
hundreds of feet in height. The waters are drained off. Hills
and ridges of different mud accumulations give form to a scene
altered and varied in every feature. But the alteration is only
external. Everything within and beneath the surface preserves
entire the character and phenomena of the laws by which the
seasons, the tides, and the atmosphere were ruled in these
ancient days. The very ripple-mark is there, attesting the
shore-lines, the flow and recess of the waters over their silty
banks. The direction of the winds are to be traced in the
general trend of the furrows impressed upon the surface. The
tiny pits and hollows of the rain-drop tell of clouds that obscured
the sky, and even the quarter of the heavens whence issued
the breeze that bore them onwards. And in the vast numbers
and the bulky forms of the fishes there is evidence of the rich
provisions of nature in supplying them with food.

How long since these things were! how very short a period
since they were regarded with either interest or understanding !
A quarter of a century has scarcely elapsed since we had any
knowledge of them at all. Dura Den was a sealed-up book, and
all its letterpress of the deep interior, and the long antepast of
historic times, unread bya single human eye. A little brief
space before this quarter of a century, and men only wondered
at the strange figures which nature presented in the rocks, and
assigned superstitious tales and occult qualities to the misun-

42 MONOGRAPH OF DURA DEN.

derstood representations of plants and animals. The past
generation actually disputed about the plastic virtues of the
earth, the mystic influences of matter, and fancied that in the
fossils they saw the sports of nature or the germs of future
creations. Scholastic theologians viewed with suspicion emblems
of living things of which they had no account to give in their
narrow interpretations of the sacred text ; and have sounded,
in many a huge folio, how.the narrative of the creative week
was endangered by the discovery of pages which they neither
deciphered nor comprehended aright.

One now smiles at the recollection of the simple and casual
manner in which attention was gradually awakened to these
interesting relics. We think how many must have been de-
stroyed through ignorance or carelessness ; how many a rich
fossiliferous neuk must have been exhausted, by sheer in-
difference to gather up the curiosities exposed to view. An
esteemed lady of the ancient house of Fingask, Miss Murray
Thriepland, and imbued with a fine taste for things of anti-
quarian research, was the first to place in safety, in the Perth
Museum, the earliest fossil relic from the quarries of Clash-
bennie, now figured and described by Dr. Fleming in No. IL.
of the New Series of the Edinburgh Journal of Natural and
Geographical Science for 1830. A student of St. Andrews
University brought to the same distinguished naturalist, in the
summer of 1827, a few scales on a piece of sandstone from
Drumdryan, a mile to the westward of Dura Den, which are
figured in the same paper, and noticed as probably belonging to
a fish of the vertebrated class. Mr. David Buist, a land-sur-
veyor in Perth, invited the writer to see his collection of Scot-
tish pebbles, cairngorms, and other crystals, in the autumn of
1828, when my eye was arrested by some pieces of red sand-
stone which were covered with large whitish scales, regarded
at the time as oyster shells from Coupar-Angus and Clash-
bennie quarries, but now better known as the appendages of
Holoptychius Murchisoni and H. noblissimus. While engaged

HISTORY OF THE FOSSIL REMAINS. 43

at a meeting of Presbytery, in a discussion on ecclesiastical
matters, in the spring of 1836, a mason called me out and
showed me an entire fossil fish, plump and round in shape,
“ which leaped into his hands,” he said, at the opening of a slab
in Dura Den ; this specimen was the first that was figured of the
family of holoptychius, and is fully described in the Monograph
of Agassiz on the Old Red sandstone, as Holoptychius Ander-
soni, the most abundant of all the fossil relics and species in
this celebrated locality. The Clashbennie quarry has been
worked for upwards of a century, during which period what
destruction of its varied treasures. As Isaak Walton might
say, we ourselves had a glorious nibble of the great Fish, when,
on the 19th March 1839, in company with Dr. Malcolmson, |
visited the quarry, and found the workmen on a rich bed of
fossils and rudely smashing a large fin— cautioned them
against the rough operation—and promised a reward for the
chance-find on the flag-stone. Next day the splendid specimen
was in the hands of another. Now it fittingly reposes among
the trophies of the British Museum—but no fin, save sadly
mutilated.

Many labourers were now in the field, and many provisional
names were bestowed on fossils that were afterwards to be
changed as their characters became better understood. The
rich deposits of the chalk in the south, and the pitchy-stained
flagstones of Caithness and the Orkneys in the north, were
eagerly explored, as each seemed the terminal points of organic
life at the two extremes of the geological scale. The tertiaries
had not as yet attracted the eloquent pen of Sir Charles Lyell
to record their remarkable divisional histories. The domains
of Siluria had no place in the system. The Old Red was just
settling into position, and casting about for a distinctive appel-
lation, under the hard, dry details of Hibbert, Sedgwick, and
Trail. And Hugh Miller, without chart or compass, was navi-
gating the creeks and bays of Cromarty, gathering and laying
up creatures of new and strange mould, or gazing with blank

44 MONOGRAPH OF DURA DEN.

wonderment on forms of which no one could tell him the names,
or furnish him a key to unravel the mystery of the rocks in
which they were entombed.

But the master-hand of Louis Agassiz was at work also, who,
in his Synoptical Table of British Fossil Fishes, reported to the
British Association in 1843, the discovery of sixty-four generic
and specific forms of ichthyologic life in the Devonian system
of rocks alone, chiefly from the Caithness, Moray, Perth, and
Fife members of the Old Red. The list has been since greatly
extended. And now, in the last edition of St/wria, there are
enumerated about forty genera, and nearly two hundred species
of the fish and crustacean types, as found in this system of
rocks in Britain, Russia, and America. Agassiz notices only
six genera of ichthyolites, crustaceans, and plants belonging
to the great Silurian formation ; the list in Murchison’s new work
shows an increase of at least fifty new genera and of five or six
hundred species, and all of most remarkable characters and
forms, chiefly of the invertebrata and the crustacea.

“ Geologists,” says M. Agassiz,* “hardly seem to appre-
ciate fully the whole extent of the intricate relations exhibited
by the animals and plants whose remains are found in the
different successive geological formations. I do not mean to
say that the investigations we possess respecting the zoolo-
gical and botanical characters of these remains are not remark-
able for the accuracy and for the ingenuity with which they
have been traced. On the contrary, having myself thus far
devoted the better part of my life to the investigation of fossil
remains, I have learned early, from the difficulties inherent in
the subject, better to appreciate the wonderful skill, the high
intellectual powers, the vast erudition displayed in the investi-
gations of Cuvier and his successors upon the faune and flore
of past ages. But I cannot refrain from expressing my wonder
at the puerility of the discussions in which some geologists allow

* Contributions to the Natural History of the United States. Ty L. Agassiz. Vol. i.
pp. 93, 94. Little, Brown, and Co., London. 1857.

HISTORY OF THE FOSSIL REMAINS. 45

themselves still to indulge, in the face of such a vast amount of
well-digested facts as our science now possesses. They have
hardly yet learned to see that there exists a definite order in
the succession of these innumerable extinct beings, and of the
relations of this gradation to the great features exhibited by
the animal kingdom : of the great fact, that the development of
LIFE is the prominent trait in the history of our globe, they
seem either to know nothing, or to look upon it only as a
vague speculation, plausible perhaps, but hardly deserving
the notice of sober science.

“ Tt is true, Paleontology as a science is very young ; it has
had to fight its course through the unrelenting opposition of .
ignorance and prejudice. What amount of labour and patience
it has cost only to establish the fact that fossils are really the
remains of animals and plants that once actually lived upon
the earth, only those know who are familiar with the history of
the science. Then it had to be proved that they are not the
wrecks of the Mosaic Deluge, which for a time was the prevail-
ing opinion, even among scientific men! After Cuvier had
shown, beyond question, that they are the remains of animals
no longer to be found upon earth among the living, Paleeon-
tology acquired for the first time a solid basis. Yet what an
amount of labour it has cost to ascertain, by direct evidence,
how these remains are distributed in the solid crust of our
vlobe,—what are the differences they exhibit in successive
formations,—what is their geographical distribution, only
those can fully appreciate who have had a hand in the work.
And even now, how many important questions still await an
answer !”

One result stands now unquestioned: the existence during
each great geological era of an assemblage of animals and plants
differing essentially for each period. Hence those minor sub-
divisions in the successive sets of beds of rocks which constitute
the stratified crust of our globe, the number of which is daily
increasing, as our investigations become more extensive and

A6 MONOGRAFH OF DURA DEN.

more precise. Along the line of our geological section, from the
azoic members of the primary series to the upper fossiliferous
strata of the Devonian system, there are at least three well-
characterized suites of rocks, with their correlative enclosed
organic remains. The lower grey sandstones represent a zone
of life when huge crustacean types prevailed in the seas and
estuaries of the district, in the remarkable forms of pterogotus,
pterichthys, cephalaspis, coccosteus, himantopterus, and stylon-
urus. Next appeared the thick, shining-scaled sauroids and
calacanths, represented by dipterus, osteolepis, cheiracanthus,
dendrodus, acanthodi, and other genera of cartilaginous fishes.
The highest zone of the period embraces the red and yellow
sandstones of Clashbennie and Dura Den, when the holoptychius
family appears for the first time in countless numbers and
gigantic forms, and accompanied by congeners of strong affini-
ties in size and scaly armature, as the platygnathus, glypto-
pomus, glyptolepis, phyllolepis, diplopterus, and now, as in this
work for the first time figured and described, the Glyptolemus
and the Phaneropleuron. The grand Epos of organic life
immediately succeeds, ushered in by a vast profusion of plants,
countless multitudes of molluscs, an extraordinary increase of

?

fishes which “ the waters brought forth abundantly ;” and now
also, as appears to be clearly established, the higher reptilian
structure of organization is brought upon the scene. Thus the
tribes and products of the carboniferous age have their repre-
sentatives among the plants in immense varieties of ferns,
lycopodiums, calamites, sigillaria, lepidodendrons, conifers, and
cycadece ; among the shell forms are the encrinites, producti,
inocerami, pectens, mytilli, orthes, spirifers, bellerophons, go-
niatites, nautili, and orthoceratites ; among the fishes are the
well-marked amblypterus, paleoniscus, gyracanthus, cteracan-
thus, eurypterus, and megalichthys ; and all of whose combined
remains now constitute our rich deposits of coals, ironstone
bands, and lofty mountains of limestone.

Dura Den stands on the verge of the two great epochs—

HISTORY OF THE FOSSIL REMAINS. 47

marking the outgoing and the incoming of the two most re-
markable phenomenal aspects of the physical history of our
planet—and the products of which, garnered up in ages long
past, are now so essential to our progress in art, science, and
commercial enterprise.

The fishes up to this period are all of a type, and are modelled
according to a special plan, both in the scaly envelope and
osseous structure. The interior skeleton is composed of car-
tilage, and the outward covering of true bone, the scales, fins,
tail, and external plates of the head being all constructed of
bony material. The back-bone, or dermal ridge, extends to the
extremity of the tail-fin, thus at once adding strength to the
cartilaginous body, and giving a greater degree of propelling
power to its caudal organ. It is hence called Heterocercat,
in contrast with all existing fishes whose back-bone terminates
within the tail-fin, and is therefore termed the Homocrrcat, or
equally-lobed structure. The existing ray, shark, and sturgeon
are exceptional cases. Hence in these and in some other
respects, especially in their dentition, Agassiz remarks that the
fishes of this period all partake, more or less, of the characters
which, at a later time, are exclusively found in reptiles, and no
longer belong to the fishes of the present day. They are there-
fore classed among the Order of Saurozds, to denote their rep-
tilian affinities ; and thus Agassiz considers that “the earliest
fishes are rather the oldest representatives of the type of ver-
tebrata than of the class of fishes, and that this class assumes
only its proper characters after the introduction of the class of
reptiles upon earth.” *

It should be the great aim of the geologist, in following out
these generalizations, to ascertain with more and more pre-
cision the true affinities of the groups of the same zone and
period to one another, and to those especially of the preceding
and following epochs; and thus to note the character of the
successive changes the organic kingdom has undergone, the

* Hssay on Classisication, p. 110, by M. Agassiz.

48 MONOGRAPH OF DURA DEN.

combination of the successive tribes into distinct faunze and
floree during each period of change, and to gain some insight,
if possible, into the causes, or even the circumstances, under
which the changes themselves may have taken place. Our
small contribution to this interesting department of Palzon-
tology comprises a group of creatures, which, in structure and
form, have many affinities to each other, and comparatively
few to the occupants of the waters in succeeding times, or
to any now living; and, in point of geographical distribu-
tion, our. field of review is of very .limited extent, covering
only as yet a few square yards of fossiliferous sandstone, lying
on the confines of the Devonian and Carboniferous epochs of
organic life.

Sphenopteris Affinis.

(Carboniferous Sandstone of Dura Den.)

Fig. 3.

Holoptychius Andersoni.—Aa.

HISTORY OF THE FOSSIL REMAINS.

Pamphractus Andersoni.—AG.
Pterichthys Hydrophilus.—He.

Diplopterus Dalgleisiensis.—Ac.

THE FIRST GROUP OF FOSSIL REMAINS DISCOVERED IN DURA

D

49

Prats I.

Fig, 2

Platygnathus Jamesoni —AG.

Fig, 4.

DEN, 1836.

50 MONOGRAPH OF DURA DEN.

CHAPTER iv:
DESCRIPTION OF THE FOSSIL REMAINS.

THE generic and specific descriptions of several of this
remarkable group of fossils are already well known to geo-
logists by the works of M. Agassiz, the Poissons Fossiles and
the Monographie du Vieux Grés Rouge, and which we mainly
adopt in the following abridgment of his more elaborate
details. The contributions of my distinguished friend Pro-
fessor Huxley now for the first time enrich the science of
Paleontology, and cannot fail to be deeply interesting, espe-
cially in the new views advanced on the affinities of the genus
Holoptychius. is descriptions of the new genus Phanero-
pleuron show the importance to all fossil collectors of carefully
preserving every organic fragment, however small, they may
casually obtain,—the several portions of this beautiful repre-
sentation having been procured by me at the intervals of
many years—some twenty years ago, some ten, the last within
the present year, furnishing the large development of the
caudal and dorsal fins—and now out of all, in the hands of the
scientific artificer, the perfected model of this unknown crea-
ture of the rocks. Agassiz first named this fish Glypticus
simply, but, from the fuller and more perfect specimens lately
submitted to him, he agrees to the more descriptive appella-
tion now assigned by Professor Huxley.

The Plates VII. and VIII., from the beautiful drawings of
Lady Kinnaird, show the figures of the fishes as they lie in the

E

DESCRIPTION OF THE FOSSIL REMAINS. 51

matrix, in their full rounded forms, and each a third part of
their natural sizes. The large caudal system of fins in Plate
VIII. fig. 1, is nine inches and a quarter in length, and five
inches and nearly a half in breadth, and, adjoined to the
holoptychius in Plate VII., renders the restored length of that
magnificent specimen to be about forty-two inches. The
greatest breadth in the anterior part of the body is fully
thirteen inches and a half. In both, the pictorial effect, which
was chiefly aimed at, is finely brought out according to Nature’s
own arrangement in her enduring and faithful lithograph.

The fishes of the Old Red Sandstone formation all belong to
the placoid and ganoid orders; and their families are repre-
sented by the lepidoids, the sauroids, and celacanths. The
fossil remains of Dura Den fall to be arranged under these
natural divisions, and furnish of their several kinds perhaps
the best specimens, in perfect outline and preservation, that
have anywhere been detected in the rocks of the earth. “ Geo-
logy demonstrates,” says Professor Owen, “that the creative
force has not deserted this earth during any of her epochs of
time ; and that in respect to no one class of animals has the
manifestation of that force been limited to one epoch. Not a
species of fish that now lives, but has come into being during a
comparatively recent period: the existing species were pre-
ceded by other species, and these again by others still more
different from the present. No existing genus of fishes can be
traced back beyond a moiety of known creative time. Two
entire orders (cycloids and ctenoids) have come into being, and
have almost superseded two other orders (ganoids and placoids)
since the newest or latest of the secondary formations of the
earth’s crust.”*

* Address by Richard Owen, V.P-.R.S., to the British Association at Leeds, 1858.

52 MONOGRAPH OF DURA DEN.

Pamphractus Andersoii.—AGAssiz.
Pterichthys hydrophilus.—KcERToN.

The bed of rock in which specimens of this genus (PI. I. fig. 1) were found,
is about fifty feet above the holoptychius bed, which lies in the bottom of the
ravine, and on a level with the rivulet which traverses it. A small project-
ing ledge of sandstone was cleared away twenty-four years ago, and then,
and never since, this singular mine of fossil wealth was laid open. The
fossil spot, according to the inquiries I made at the time, was literally
blackened by the shoal of “ frog-like creatures,” as the workmen termed
them, exposed to view; but so friable was the stone in which they were em-
bedded, that few of the forms were preserved entire. Many were carried
away, and others speedily reduced to dust. One flag only, with thirty-three
impressions, and about two feet square, was saved at the time from the
wreck. A portion of this slab was forwarded by me to Agassiz, then resident
at Neufchatel ; another is now in the Agricultural Geological Museum at
Edinburgh ; a fragment has been deposited in the British Museum at Lon-
don; and the remaining portion, in the possession of the proprietor of Dura
Den, has gradually yielded to the influence of decay, the figures being much
injured and obliterated.

The history of this remarkable fossil is now, therefore, chiefly to be read
in the earlier discussions that took place immediately upon the discovery.
These are to be found in the Poissons Fossiles and the Monograph on the Old
Red, of Agassiz; in the Old Red Sandstone of Hugh Miller ; the Palichthyo-
logic Notes of Sir Philip Egerton ; and in the Course of Creation and Prize
Essay of the author.

These curious crustacean fossils, when transmitted to Neufchatel, were at
first regarded by M. Agassiz to belong to the genus Pterichthys ; but upon a
more minute examination of the new group cephalaspis, coccosteus, and
pterichthys, Agassiz was convinced of distinctions not formerly observed.
“T had,” he says, “at first connected pterichthys, the only species known
of that genus, by calling it Pterichthys hydrophilus ; but a more profound
study and attentive comparison of that species with the genus coccosteus,
have proved that it ought to form a distinct genus, intermediate betwixt
pterichthys and coccosteus, which I have named Pamphractus, in consequence
of the divided form of the carapace. The pectoral fins of pamphractus re-
semble very much those of pterichthys in their form—being slender, elongated,
and crooked. But the plates of the carapace are all differently arranged.
The central plate is very large (énorme) ; it covers two-thirds of the whole
carapace. The lateral plates, which acquire so great a development in the
pterichthys, are here reduced to narrow stripes, stretching to the edge of the
carapace ; while, on the other hand, the posterior plates are of very great
size, and form, with a small intercalated plate, the extremity of the carapace.
The disposition of the plates of the head is likewise very different from that
of the pterichthys, in which we discern no thoracic cincture as in that genus,
but a transverse line, which separates, in a striking manner, the plates of the

DESCRIPTION OF THE FOSSIL REMAINS. 53

head from those of the carapace. . . . The excessive development, in
short,” he concludes, ‘‘of the central plate of the carapace, which reaches the
articulation of the head, the absence of a thoracic cincture making the round
of the body, and the distinct separation of the occipital articulation, will
always distinguish this genus from that of pterichthys.”’

This is decisive language, nor is anything more of descriptive detail re-
quired to make the structure and the generic characters of pamphractus
thoroughly understood. But as matter of geological history, as well as of
controversy, it may be proper to state, that when the accuracy of these dis-
tinctions was challenged by Dr. Fleming and Hugh Miller, upon the ground
of alleged exaggerations in my plate-figures, Agassiz at once repelled the
assertion. The impressions on the fossil slab forwarded to Neufchatel are
ELEVEN in number, three of the “ broad”’ and eight of the ‘‘ narrow ”’ species;
and comparing the one with the other, the print with the fossils, he records,
“They have been figured very fairly by Dr. Anderson, in his interesting
Memoir on the Geology of Fifeshire.”’ The print, in fact, is a perfect tran-
script of the fossil, as if taken in a mould, curves, projections, plates, arms,
and tubercles all duly and “fairly ”’ preserved as in the original; and with
all the materials, and so many actual forms of the creature before him,
Agassiz hesitated not to change his views, and to feel assured that it was
really a pamphractus, and not a pterichthys that he was examining, and de-
cided for the new genus accordingly.*

Sir Philip Egerton, however, and I believe many other eminent authorities,
dissent from the views of M. Agassiz on the revised and altered cognomen of
the Dura Den fossil. In a conjunct paper read before the Geological Society
of London on the 19th April 1848, and published thereafter in the Transac-
tions of the year, there occurs the following statement :—‘ In searching for
further evidence in support of my views, by comparing pterichthys with the
description and figures given by Agassiz of the allied genera, I have been
surprised by the great similarity between the restoration of the genus Pam-
phractus and the dorsal integuments of Pterichthys. Having never seen a
specimen of Pamphractus, I should not be justified in expressing any positive
opinion regarding this genus, but I cannot help thinking that it is founded
on a specimen showing the true dorsal arrangement of the lorication of Pter-
ichthys. . . . The most important point for my argument is fortunately
that which is best known, namely, the occurrence of a central lozenge-shaped

* Dr. Anderson, dans une notice trés-intéressante qu'il a publiée sur la Géologie et la
Botanique du comté de Fife, donne la figure d’un poisson (Fig. 6 de sa planche) qui res-
semble beaucoup 4 mon Pamphractus hydrophilus, mais qui en différe cependant par la forme
plus allongée de la téte et par le développement de la ceinture thoracique qui est visible
entre la téte et la carapace. A moins que ces différences ne soient l’expression des carac-
téres particuliers des faces supérieure et inférieure de la carapace, que je n’ai pas pu com-
parer entre elles, il faudra considérer ce fossile comme une espéce particuliére que je signale
& Pattention des géologues écossais, en proposant de ]’appeler Pamphractus Andersoni. Je
suis d’autant plus disposé a considérer le poisson de Dr. Anderson comme une espéce A part,
que la forme de ses contours différe de celle du Pamphractus hydrophilus; mais une com-
paraison d’un nombre plus considérable d’exemplaires mieux conservés pourra seule décider
cette question.— Monographie, Chap. iii.

DA MONOGRAFH OF DURA DEN.

plate, similar in form, in position and structure, to that found in Péerichthys.
This plate characterizes the ventral region of the fish, and thus affords Te-
markable testimony to the accuracy of the view I have taken in assigning
the like position to the homologous plate in Pterichthys.’”*

Since the publication of this paper I believe M. Agassiz has not again
turned his attention to the subject, nor amidst his numerous elaborate inves-
tigations has had either leisure or opportunity of doing so. But in a commu-
nication I recently had the honour to be favoured with, he says, ‘“‘ You must
know that I have had no opportunity of making a renewed examination of
the Dura Den fossils since I was favoured with a sight of those you forwarded
to me at Neufchatel twenty years ago, and that I have no chance whatsoever
of making now the comparisons necessary to verify the suggestions of Sir
Philip Egerton. At the same time, I have, like all those who know him,
such implicit confidence in his accuracy and ability to decide in such matters,
that I should feel reluctant to insist upon the correctness of my own opinions,
expressed so long ago, in contradiction to$his views, resulting from a more
recent examination of the facts. I have not the remotest doubt that Sir P.
Egerton has shown a closer affinity to exist between the Pamphractus Ander-
soni and the species of Pterichthys proper, than I supposed there was between
them. Still I am not yet, on that account, satisfied that the genus pamphrac-
tus must be given up. Judging from my figures and descriptions, I am now
inclined to believe that coccosteus and cephalaspis can no longer remain in
one and the same family with pterichthys. Again, the views I have pre-
sented respecting the limitation of genera in my Essay on Classification, will
require a revision of all the pterichthys, with reference to their genuine char-
acters, and I look forward, from the indications I can gather in my own
work, to the necessity rather of subdividing the species which have been
united as pterichthys into several genera, than to the propriety of combining
pamphractus and pterichthys. I throw out this suggestion for your considera-
tion, and must leave it to the paleontologists who have the necessary materials
on hand finally to settle these points.”+

While these generic resemblances, as well as distinctions, must be left for
future revision and determination, let it be observed that pterichthys, cepha-
laspis, coccosteus, and pamphractus are all of the family type of Lepidoides,
and have such affinity in outward form as readily, in mutilated specimens at
least, to be mistaken for each other. The appendages of the head, having
the appearance of wings, suggested the terms of Pterichthys, or the winged
fish (pteros, a wing ; ichthys, a fish). The plates covering the body, according
to their number and position and form, gave rise to the generic distinctions,
and the species of each have been determined by minor differences. The
external organs in all are enamelled, and discover, like all the crustacea of
the period, the tuberculated surface. The pterichthys of the northern coun-
ties, in Cromarty, Moray, and Elgin, vary in size from nearly a foot to an
inch in length, and the wings generally are extended perpendicularly to the
body. The pamphractus of Dura Den are all of a size, from two inches to

* Vol. iv. p. 308. + Dated Boston, Cambridge, U.S., 4th December 1858.

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DESCRIPTION OF THE FOSSIL REMAINS. a5

three inches in length, and about an inch and a half in breadth; the wings,
in every specimen yet discovered, are depressed and inclined to the sides ;
and in no instance has any portion of the caudal organ been detected, in the
least remaining tracery or impression. The carapace, in all the plates and
lateral appendages, is fully defined ; and, as remarked by Hugh Miller upon a
reconsideration of my specimens presented to the Edinburgh Geological and
Agricultural Museum, “ one of the most striking specific distinctions of the
Pamphractus Andersoni consists in the length and bulk of the arms, and the
comparatively great prominence of those angular projections by which they
are studded on the edges,’’—projections which seem to be but expansions of
those confluent lines of tubercles by which the arms of all the numerous
species of the genus pterichthys are fringed.

Glyptopomus minor.— AGASSIZ. Pr. TE

“‘T am only acquainted,” says M. Agassiz, ‘‘ with a single specimen of this
genus, from the collection of Professor Jameson, which I at first took for a
Platygnathus. Afterwards, when I had leisure to make a more minute exa-
mination, I was soon convinced that, notwithstanding the resemblance of its
exterior with the platygnathus, it was distinguished by particulars of struc-
ture too important to admit of its remaining associated with this type, and
consequently I was obliged to form a separate genus.”

We may now perhaps express our surprise that, by so discriminating a
judge of fossil fishes, a moment’s hesitation could have existed as to the wide
and obvious distinctions manifest in every outline of the specimens in question.
That the Glyptopomus and the Asterolepis might for a time be confounded,
one can readily admit, more especially so long as only the scales and plates
of the latter were the sole means of comparison. But in nothing do the
platygnathus and the glyptopomus, in general appearance and external struc-
ture, seem to bear the slightest resemblance.

The differences, as pointed out in the Monographie du Vieux Gres Rouge,
upon subsequent examination are very clearly stated. ‘The scales of the
platygnathus are round and imbricated, so that the posterior edge of one scale
covers the anterior edge of the following one, and possessing in this respect
all the characteristics of the scales of the celacanths ; on the other hand,
those of the glyptopomus resemble the scales of the sauroids, which are
rhomboidal or quadrangular, placed in juxtaposition to each other, and are
never imbricated. Moreover, the platygnathi are elongated fishes, furnished
with a long tail and a very powerful rudder fin; whereas the glyptopomi are
much thicker, and their tails shorter and less branching in the bundles of
rays. The ornaments on the scales of the glyptopomus are deeply marked,
resembling those of the celacanths, while all the plates of the head are
strongly tuberculated with a beautiful shagreen enamel.”

This description was given by M. Agassiz upon inspection of the specimen
now in the British Museum, which bas a large thick flat body, approaching
in form to the Holoptychius Andersont. The head is proportionally small,

56 MONOGRAPH OF DURA DEN.

with the frontlets nearly in the middle; the nostrils are behind. The occi-
pital, and a great enamelled plate on the side of the head, indicate that it
was covered, like the polypterus, by a single osseous plate, under which was
fixed the great masticating muscle. A specimen now in my own possession
shows, in addition, the edge of the lower jaw, with one or two small teeth,
which is extremely strong and massive, and upwards of four inches in length.
The head is proportionally larger too, though considerably crushed on the
right side; it is invested with irregularly marked enamelled bones, which
appear, as on the other specimen, to be covered by a thick and variegated
granulation. There are no traces of the fins in either observable, except a
few straggling rays which present no characters of form, size, number, or
position.

A very large head of the same genus I afterwards found in one of my ex-
cursions to Dura Den. It measures from the snout lengthways seven inches,
and in breadth it is eight inches. It is considerably flattened by pressure,
and varies from an inch to an inch and half in thickness. The snout is
rounded ; both upper and lower sides of the entire head are exposed in the
specimen ; and the glosso-hyal, the occipital, and other plates, are in their
places and largely developed. This splendid specimen now forms part of the
Old Red collection in the British Museum, which, along with specimens of
pamphractus, holoptychius, phaneropleuron, glyptolemus, and platygnathus,
I presented to that national depository of science.

Platygnathus Jamesont.—AGAssiz.

The genus Platygnathus (P1. I. fig. 2) has been established by M. Agassiz
upon two imperfect fossil specimens, the one consisting of a jawbone, found
in the Orcades by Dr. Trail, and the other being the posterior part of the
body which were discovered in Dura Den among the first researches made in
that locality. The jawbone from the Orcades, besides in itself incomplete,
consists only of the under half of the organ, but presenting the upper side
with two large broken teeth. The interior of these incisors is filled, without
a medullar cavity, and exhibit a radiated appearance, as in the teeth of the
dendrodus. Their section is perfectly circular. The external edge of the
jawbone is likewise supplied with several ranges of small conical teeth, united
the one to the other, and considerably developed. The internal edge is
covered by a fine granulation, having the appearance of shagreen.

The Orcadean specimen is four inches and a half in length, and more
than an inch in width at the posterior part. The socket of the jaw contains
four large compartments nearly square, and formed by osseous supports ex-
tending between the external and internal branches of the jaw.

The Dura Den fossil is much finer, fuller in development, and more com-
plete in details. It is twelve inches in length, six in breadth to the upper edge
of the dorsal fin, and seems to present about a third part of the body of the
fish. How marvellous the revelations of science, which can combine from
such fragmentary relics generic alliances, and demonstrate the one, from

DESCRIPTION OF THE FOSSIL REMAINS. 5Y

such different organs, to be kindred to the other! Wide asunder in geo-
graphical area as these interesting relics were detected, they are in their
geological horizon and position still further apart—the one occupying the
lowest and the other the upper series of the Old Red formation. My unprac-
tised eye, when I first saw them and compared them side by side, could
neither guess nor decipher anything of their family relationship.

But it was chiefly upon the characters exhibited by the Dura Den fossil
that the genus was established. The resemblance to the holoptychius was
first observed, and the scales were supposed to be identical. But several
points of distinction were very marked, both in these and in other appendages
of the fish. Thus the scales in platygnathus are rounded, broader than long,
especially towards the tail. They are likewise ornamented by horizontal
well-marked lines, often interrupted, and although placed in rows they do
not form continuous crests. The lines, besides, are not so well defined nor
so strongly relieved as in the holoptychius. The tail, again, of platygnathus
is very long and contracts very gradually, which characteristics are very dif-
ferent in the other genus. ‘The fins are also much larger, the dorsals, of
which there are two, being at least twice the height of the tail, and composed
of elongated close flexible rays. The posterior extremity of this organ is
slightly raised, and on the inferior edge there may be observed a number of
short rays, which probably composed the under lobe of the fin. Under the
belly of the fish a narrow and very long fin can be distinguished, which
seems to be the anal ; it ranges along the tail, and appears to have been as
wide as the dorsal when spread out.

The great peculiarity, then, of this genus of fishes, is the enormous deve-
lopment of the fins. They are all, candal and dorsal, of the largest dimen-
sions, and heterocercal, and the vertebral column extending to the extremity
of the finny appendages, it is justly inferred that they must have been
powerful swimmers. The same organs indicate their voracity and great
development of jawbone and teeth. Hence the connexion presumed to exist
between the Orcadean and the Dura Den fossils; and, found so wide apart
as in the inferior and the upper members of the Old Red, the interest in their
discovery is all the more important and heightened by the circumstance of
their being solitary examples of their respective species, in the long-separated
periods of the geologic relations.

1. Holoptychius Andersoni.—AGAssiz. Pr fo VL Vibe
2. Holoptychius Flemingii.i—AGassiz.

The yellow sandstone of Dura Den may pre-eminently be distinguished as
the habitat of this race of fishes, since so many hundreds have been disinterred
from a single bed of the deposit, and nearly all of the same species, the Holo-
ptychius Andersoni. Our description, therefore, of this fertile family will
admit of being as particular and minute as we have access to the writings of
its most celebrated historians.

The Scales.—The characters of the scales are remarkably striking in all

58 MONOGRAPH OF DURA DEN.

the species, as well as individuals of this type of fishes. They are extremely
ornamental, regularly and beautifully arranged, and cannot fail to fill with
admiration the most indifferent observer. Their glossiness of colour, roundness
of form, firmness of texture, deep-set groovings of tracery, and comparative
largeness of size, at once mark the family as one of peculiar interest, a sin-
gular combination of strength and harmony in animal structure. ‘They have
been represented as “ the scavengers” of the seas in ancient geologic times;
we would rather say they were the “rover-kings” who issued from their
rocky fastnesses, armed cap-a-pie in cuirass and mail, and able to do battle
with every ocean tribe that opposed them.

The scales, according to M. Agassiz, consisted of a dense, thick osseous
substance, formed in parallel and superposed beds, and turned against the
inner edge of the skin, while concentrated markings of growth, repeating
the figures of the scales, are distinctly traceable over all the surface. They
are crossed by fine rays, radiating from the centre outwards, which are formed
by very delicate channels scarcely in relief, and in which were probably fixed
the fibres of the skin. Numerous small canals, conductors of the blood-
vessels, ascend by these rays into the substance of the scales, and near the
surface they branch out horizontally, forming a very straight net-work of
mail. Above this net-work—indicating the space between the osseous and
enamelled substances—lies the enamelled bed which occasions the external
ornament and fine-tint material of the organ, and the bed itself is only a
thicker osseous membrane through which the corpuscules are ramified and
diffused.

The form of the scales is uniformly, in all the Old Red species at least,
oval or rounded, and many of them on particular parts of the body, are nearly
circular. This is remarkably the case with all on the ventral side, which by
compression, I observe, in a great many instances, are detached or in slightly
connected rows, and the circular tendency is clearly manifested. The scales
are imbricated, or slightly raised—the one edge of the superior, along the
median line, and from the head lengthways, over the posterior in their suc-
cessive courses. The covered part is smooth and devoid of ornaments, whilst
the exposed part of the surface is richly ornamented by longitudinal ridges
and eminences, radiating, or more and less diffused, extending to the extre-
mities, or leaving an outer border and even selvedge across the edge of the
scale. The arrangement of these ridges and groovings serve not only to distin-
guish the different species, but to determine the character and to give name to
the genus—Holoptychius—the holos and ptyché—the entire wrinkled scale fish.

The mode of formation of this organ in fishes resembles the growth of hair,
feathers, and wool in other animals, and consists of nearly the same elements
as hoofs, beaks, claws, and nails. An extremely delicate and finely organized
pulp, composed partly of a congeries of minute vessels, and partly of a gela-
tinous substance in which these vessels are imbedded, constitutes the appa-
ratus by which the nutrient particles are selected, combined and elaborated
into the materials of the intended structure. ‘The original form, situation,
disposition, and mass of this vascular pulp, determine the future figure and
extent of the growth of the organ on the several kinds of fishes to which they

_

eee E> lt EE

DESCRIPTION OF THE FOSSIL REMAINS. 59

are attached. Hence scales vary remarkably in their form, structure, mode
of adhesion, and position in different families. In general, they may be
described as flat plates, variously marked and laminated. The plates in
some classes are more numerous than in others, the lowest are the largest,
and the upper surface becomes in consequence somewhat imbricated. The
breadth of each new layer is greater than the last, its edges project farther,
and gradually the whole surface assumes that concentric striated appearance
which renders it so characteristic a feature in all the scales of the Dura Den
fossils. The scales in the genus holoptychius are imbricated, with the distal
edge free, and the epidermis enveloping their base. But in other fishes, as
glyptopomus and diplopterus, where the scales are remarkably thick, they are
arranged laterally, without resting upon each other, and have a covering of
the epidermis spread over them, or uniting them at their base.

The materials of which scales are composed are deposited sometimes in
masses, as in the scales of the crocodile; in filaments, as in hairs; and in
layers, as in hoofs, nails, and scales of fishes. The annual additions are made
to them at their base, or root, where the vessels deposit fresh materials, and
they gradually increase in size, protrude and extend along the skin, and
continue to grow by the same process as long as these vessels continue in
activity. Hence, as by the horns of mammalia, the plates of insects, and the
concentric rings in the woody tissue of trees, the age of fishes may likewise
be determined by the successive increments of growth to their scaly envelope.
The scales of the holoptychius sometimes attain to an enormous size, those
from Clashbennie and Parkhill, in the author’s possession, exceeding three
inches in length, by two inches in breadth, and the wrinkled strie raised in
proportional depth. The constituents of a scale from Clashbennie of this
genus, analysed by Professor A. Connell, and published in the Edinburgh
New Philosophical Journal, are as follows, viz. :—

Phosphate of lime, with a little fluoride of calcium, . 91°42
Carbonate of lime, . , 2 : : : : : 7:05
Chloride of potassium, . < 5 ; : : : 0:27
Chloride of water, . - ; : : : é : 0:97
Sandstone matrix, ; : P : : 2°38
Phosphate of magnesia and animal matter, trace,

102-09

The Head.—This organ in the genus holoptychius is proportional and in
keeping with the general size of the fish. All the bones are incrusted with
a thick coating of enamel, slightly marked, and almost the same as the
cephalic bones or the scales of the sturgeons. The external surface is rough,
forming a coarse granulation, approaching the deep wrinkles with which the
scales are ornamented. The under jaws are large, curved, forming a half
circle round the head, and incrusted all over with a granulated enamel. The
branchiotic rays are supplied, as in most of the ancient sauroids, and as in the
living polypterus of the African rivers, by two large enamelled plates uniting
at the median line, and filling all the opening of the throat between the two
branches of the lower jaw. They are termed the glosso-hyal plates, which
are the supporters of the lower jaw, and resemble very much the corresponding

60 MONOGRAPH OF DURA DEN.

plates in the existing Sudis gigas of South America. The huge Wegalichthys
of our coal-fields, so common in the iron-band shales of Fifeshire, possessed
three of these glosso-hyal pillars, as if nature in her arrangements had made
size a condition of organic structure. These two plates in the holoptychius
and other Dura Den ganoids are moveable, and seem to have been constructed
so as to change their true signification, and especially, when dislocated with
a view to cover their edges, would serve as frontlets under the eyes. The
bones of the skull, in this as in all sauroid fishes, are united by closer sutures
than those of existing fishes. The vertebra articulate with the spinous pro-
cesses by sutures, like the vertebra of saurians; and the ribs also articulate
with the extremities of the spinous processes. The caudal vertebre have
distinct chevron bones, and the general condition of the whole skeleton is
stronger ad more solid than in other fishes.

The Teeth—The family of fishes, including holoptychius under considera-
tion, have many characters in common with the class of reptiles, and among
these the teeth are more especially allied to the reptilian type. They are
striated longitudinally towards the base, and have a hollow cone within; and
the bones of the palate are also furnished, as in that order, with a large appa-
ratus of teeth, their back edges terminating in a sharp point, which rendered
them singularly adapted to drag and to lacerate. Another provision, strongly
allied to the dentition of the lizard-type, consists in the manner in which
these teeth were inserted in the jaw, with their roots entangled and ramified
through the osseous substance, and thus indicating the violence with which
they could be sunk into the body of a living fish. There was a double row
_ or set of teeth in the lower jaw, consisting of three or more, larger, and others
much smaller and less acute, placed in the interstices of the bony matrix; a
condition of arrangement existing likewise in the voracious family of the
megalichthys, and serving, not so much perhaps for mastication, as a provi-
sional apparatus for securing the slippery bodies of their prey when dragged
into the mouth.

The Fins.—M. Agassiz, generally from incomplete specimens, but with his
usual skill and sagacity, had clearly defined the nature and positions of the
fin-organs in the genus Holoptychius ; and, where the information could not
be supplied by the specimens submitted, he had conjecturally, but most accu-
rately, assumed what Nature herself must have done in the circumstances.
We have a remarkable instance of this in his succinct but lucid description
of the arrangement of the fins on the Holoptychius nobilissimus. ‘‘ At pre-
sent,” he says, “I only know of the ventral and base of the caudal fins,
which are visible on the magnificent specimen of the Holoptychzus nobilissimus
in the collection of the British Museum, and which I have represented in
Plate 22.* The ventral fins are very much thrown back, the one far distant
from the other, and carried back on the sides of the belly to the anal opening.
They are small, composed of several rays, but they are not in good enough
preservation for me to give more particular details of their form and struc-
ture. The caudal has a strong radius, which leads me to suppose considerable
development of that locomotive appendage. The pectorals appear to have been

* Monographie des Poissons Fossiles du Vieux Grés Rouge, Chap..1y. Plate F.

DESCRIPTION OF THE FOSSIL REMAINS. 61

small, and placed high up on the sides of the body, the thoracic girdle rather
feeble, and there seems to have been but slight development of these fins.”

Had the whole recent discoveries of Dura Den been lying on the cabinet-
tables of the eminent naturalist, he could not have furnished, from a com-
parison of the mass of specimens before him, anything more descriptive and
accurate than what is here related. From an examination of hundreds of the
most clearly-defined fossil remains, of all sizes of bodies, from six inches to
forty, we have been able to verify every one of the details in the picture.
The vast depth and breadth over the shoulders of the large specimen recently
dug up in Dura Den, show how well Nature has attended to the laws of
gravity and equipoise in placing, as she there has done, the pectorals “ high
up on the sides of the body ;” while Agassiz’ own profound knowledge of
structural conditions is verified to the letter in the “‘ considerable development
of that locomotive appendage,” the caudal fin, or, rather I should say, the
system of fins. The specimen of this organ now in Lord Kinnaird’s collec-
tion measures exactly nine inches in length from the termination of the
scales to the extremity of the fin-rays in the tail; it is five inches and a half
in breadth, and consists of three distinct groups or cords of rays, uniting at
the roots, but separable outwardly on their extended radius. The form of
this powerful propeller, on the terminal fulcrum of motion and strength,
is that of a graceful fan in repose, and shows its expansive capacity of
development, when unfolded, in the massive assemblage of filaments of which
it is constructed.

Nor, let it be remarked, does this thick and condensed cordage of fin-sub-
stance conceal the normal structure of the caudal portion of the skeleton. The |
normal arrangements are fully manifested, where in this largely developed
specimen the upper fin-lobe is comparatively smaller, and the extended verte-
bral column very distinctly defined. It is the same in one and all of the
innumerable specimens furnished in this prolific locality. And I simply
notice the fact, because in the last posthumous edition of the Old Red
Sandstone of Hugh Miller, a figure of the Holoptychius, from Dura Den, is
there given with the homocercal representation of the fin-organ, and shorten-
ing of the vertebral column. The engraving, in every particular, is defec-
tive in execution; and compared with the fossil specimen itself, it is equally
defective in the scales, and inaccurate in omitting the vertebral column,
which in the specimen is distinctly traceable to the extremity of the tail-fin.

There are fourteen species of this genus known and described, of which six
belong to the Old Red and eight to the coal measures. Their chief distinc-
tions consist in the form and granulation of the scales, and in the size and
position of the fins. Thus the scales of Holoptychius Flemingii are very much
longer than broad on the sides, but round under the belly, and the ornaments
form undulating lines running horizontally towards the posterior edge, without
any visible ramification. The Holoptychius Andersoni is partly characterized
by the absence of the tubercular zone, by the extension of the folds to the
posterior edge, and by the length equalling nearly the breadth. The scales of
Holoptychius Murchisoni differ from both in the greater elevation of the
ridges, in their distinct and confluent ramification towards the posterior

62 MONOGRAPH OF DURA DEN.

edge, and in exhibiting three well-marked zones, which are smooth in front,
and covered with rounded tubercles behind. ‘The most clearly defined
distinction in Holoptychius nobilissimus consists in the size and general
roughness of the scales, which are very large on the middle of the belly, and
become arched in diminishing gradually towards the tail. In Holoptychius
giganteus the scales are very thick, of a rounded form, resting on smooth
zones, and beautifully ornamented on the inferior side, as in the medullar
lines and osseous supports of the Glyptolepis leptopterus. Holoptychius Oma-
liusii is distinguished from all the above specific forms in the enormous
magnitude and thickness of the scales, which are deeply furrowed, with lon-
gitudinal and parallel ridges, which, from their fine irregular granulation, give
the appearance of shagreen; and, above all, by the size of a body that must
have attained the length of at least twelve feet! This fossil, but very
imperfect, has only been found in one locality, namely, in the Old Red of the
neighbourhood of Namur, by M. Omalius de Halloy. The other five species
belong to Dura Den and Clashbennie.

The specimen on which was determined the species—Holoptychius. Ander-
soni—was the first discovered of the genus in anything like completeness,
and was figured, in 1837, in my Geological and Botanical Description of
Fifeshire. The large specimen discovered in 1858, along with the massive
caudal fins, on another tablet of rock, completes the entire equipments of this
celacanthic fossil, showing it in full outline and perspective, and producing
as perfect a restoration of a form of. extinct life as any in the annals of geo-
logical discovery yet recorded. The massive dimensions to which it has
attained, and corresponding magnitude of the scales, show a very considerable
affinity and resemblance to the Clashbennie Holoptychius nobilissimus, but
besides many minute discrepancies in the granulation of the cephalic bones
and the ridgy eminences on the scales, the Dura Den fossil justifies its claims
to a specific honour, upon the ground of its occupying a position in the
upper series of the system, and thus standing so much higher in the order of
stratigraphical arrangement, and so much later in the geological horizon of
animal life.

Holoptychius Nobilissimus.—AGass1z.

my yet sor

dm: yey M ‘ ssoby -( sovade AON ) TPtTOUlay sruaojagdhyy
‘SSD ‘/ say AON / snupop a dhyy ol!

DESCRIPTION OF THE FOSSIL REMAINS. 63

The following descriptions of Glyptolemus, Phaneropleuron,
and the Structure of Holoptychius, are furnished by Professor
Huxley, whose position among our first-class men justly entitles
him to pronounce as one having authority, and whose clear
distinctions are founded upon a most extensive acquaintance
with ichthyological organization. The fine drawings and re-
stored figures, in particular, of the phaneropleuron and _ holo-
ptychius, show the results of the most patient study, elaborate
comparisons, wide generalizations, and profound knowledge of
the science of Paleontology. The specific distinction of Glyp-
tolemus Kinnairdi was proposed by me at the meeting, on
the 18th May last, of the London Geological Society, and
unanimously agreed to, in honour of Lord Kinnaird, whose
zeal in promoting the interests of geology is only equalled by
his enlightened endeavours to advance the interests of every-
thing connected with our social and industrial wellbeing as a
statesman. That an Agassiz and a Huxley have added the
weight of their high authority to both specific distinctions, in
the new genera of glyptolemus and phaneropleuron, enhances
the value of the honour to the author and his noble friend.

Glyptolemus (Nov. Genus).—-HvuX Ley. PoE IV.
Glyptolemus Kinnaird (Nov. Species).—Hvxt.ey.

The specimens upon which I have founded this new genus and species, some-
time ago became the property of the Museum of Practical Geology, with the
understanding that they should be figured for the present work, and that I
would furnish Dr. Anderson with an account of their characteristic peculiari-
ties. In the meanwhile the fish remained unnamed, but, on my exhibiting
them as new forms to Professor Agassiz,* during his recent visit to our
museum, I was glad not only to obtain his sanction to the establishment of a
new genus for them, but to adopt the name of Glyptolemus,+ which he sug-
gested on account of the marked sculpture of the jugular plates in one of the
specimens.

Of the two specimens figured, that in Plate III. affords an almost complete

* By an inadvertency the distinguished name of Agassiz has been printed in the plates
instead of Huxley. The true orthography is Glyptolemus.
+ Trurrés, Naruds.

64 MONOGRAPH OF DURA DEN.

view of the left half of the dermal skeleton from the inner side, and lies in
the same block with a number of Holoptychit.

The slender-looking fish measures fifteen inches and a half in length, while
its depth nowhere exceeds an inch and three quarters, attaining this amount
about the middle of the body, and diminishing thence with almost equal rapi-
dity towards the head and the tail. The exact length of the head is nowhere
precisely determinable, but, from the extremity of the snout to the posterior
edge of what seems to be the operculum (0) is a distance of three inches. ‘The
depth of the head, including the lower jaw, nowhere exceeds an inch.

The end of the snout is obtusely pointed, and from it, a bony bar, which
may be the remains either of the premaxillary and maxillary bones, or of
the ethmoid and sphenoid, is traceable backwards along the line of the base
of the skull. A much more slender broken line of bony matter, which attains
at most a distance of three-eighths of an inch from the preceding, is all that
remains of the roof of the cranium. The matrix fills the interspace between
these two thin portions of bone, and exhibits a faint circular impression which
may possibly have been produced by the eye.

Three-eighths of an inch from the end of the snout, the lower bony bound-
ary of the skull gives attachment to the enlarged base of a great tooth (a).
This base is fully a quarter of an inch in diameter, but the tooth rapidly
narrows, so that, although not more than an eighth of an inch of it remains,
its broken end is less than an eighth of an inch in diameter. The outer sur-
face of the tooth is marked with longitudinal striz. (See the magnified view
A.) Immediately behind this tooth is seen the impression of the pointed
apex of another large tooth which must have been implanted in the mandible.

The exposed ramus of the mandible is either broken at its extremity, or
did not extend so far forward as the premaxilla. It is very slender anteriorly,
not exceeding one-eighth of an inch in thickness, but, an inch from its an-
terior extremity, it rises into a rounded coronary elevation, and attains a depth
of one-fourth of an inch. Behind this point it is broken away.

A confused bony expansion, resulting, to all appearance, partly from the
petrosals, and partly from the pre-operculum, lies above the coronary portion of
the mandible, while, posteriorly, part of what I take to be the operculum, is seen
at 6. The surface of this bone exhibits a grooved and ridged sculpturing.

An indication of a pectoral fin is shown at c, and behind this, the inner
faces of the successive rows of rhomboidal scales are exhibited, the anterior
series being obscured by the matrix. These scales are thin, smooth internally,
and, in the middle of the body, about a sixth of an inch wide in their trans-
verse or short diameter.

The outer face of no one of these scales is exhibited, but the casts (B) left
upon the surface of the stone whence they have been detached, show that the
external surface of each scale was pitted and ridged almost as in Glypto-
pomus. The scales are, however, very much thinner and less bony than in
that fish.

The sculpture exhibits a certain tendency to a radiating arrangement, lon-
gitudinal strie diverging from the anterior to the posterior margin as is seen
in the enlarged scale B.

_MCZ LIBRARY
/ARD UNIVERSITY
IDGE. MA USA

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DESCRIPTION OF THE FOSSIL REMAINS. 65

Of the system of median fins there are two dorsals situated very far back,
the anterior edge of the root of the first being 94 inches distant from the end
of the snout. The first dorsal is remarkably slender and of a somewhat semi-
oval outline. Its base measures 9; of an inch, while its total length is
about 14 inch. Its anterior margin is nearly straight, the posterior being
much more convex. The anterior edge of the root of the second dorsal is
eleven and a half inches distant from the end of the snout. It has a very
similar form to the first dorsal, but is larger, measuring seven-eighths of an
inch along its base, and two inches along its longest axis, while its greatest
breadth is three-fourths of an inch.

The dorsal lobe of the caudal fin begins about half an inch behind the
second dorsal, and opposite the commencement of the ventral lobe, the two
lobes being very nearly equal, and the tapering caudal end of the body being
but very slightly inclined upwards. The fin rays of the ventral lobe are
stronger than those of the dorsal lobe, and the end of the fin, which attains a
width of 24 inches, is abruptly truncated, so as to be something between
triangular and round in its contour. No lateral line is distinguishable, and
there is a mere indication of what appear to be the rays of the anal or
ventral fin, opposite the first dorsal, which last indeed looks so exceedingly
like a ventral fin that I was inclined to regard it as such, until Mr. Dinkel’s
valuable suggestions led me to look into the question more carefully.

The second specimen figured (Plate IV.) under the name of Glyptolemus,
displays only the ventral surface of the anterior moiety, seven inches in
length, of a fish, whose transverse diameter nowhere exceeds two inches.
At the end of the block, to the left in the figure, the transverse section
of the body has the form of a transversely-elongated semi-oval, flat ven-
trally and convex dorsally, its depth from above downwards being about
an inch.

The symphysial end of the lower jaw is rounded, the rami measuring
about two and a quarter inches in length. Their thickness is fully one-
fourth of an inch, and posteriorly they are an inch and a half apart. The
bony substance of the jaw is very thin, and where its- outer surface is pre-
served, it exhibits a ridged sculpture.

The middle of the interval between the rami is filled by two large jugular
plates, which are separated from the rami by, apparently, five small plates on
each side.

The large jugular plates have an elongated triangular form, and are two
and a quarter inches long, half an inch broad at the broadest ; the left being
rather wider than the right, and overlapping the latter by its uneven inner
edge. The bones are thin, and their posterior margins are rounded ; that of
the right side being broken.

The surface of the plates exhibits a pitted and lineated sculpture, which is
so disposed as to radiate from a point near the outer margin of each plate ;
and, at about the junction of its anterior two-fifths with its posterior three-
fifths, the sculpture of the posterior part of the anterior division of each plate
is particularly coarsely reticulated.

The small lateral jugular bones increase in length and in width from before
backwards, and exhibit a pitted or reticulated sculpture, which is coarsest in

E

66 MONOGRAPH OF DURA DEN.

the most posterior and largest of the plates on each side. The hinder edge of
this is overlapped by the lowest of the opercular bones, which exhibits a well-
marked ridged sculpture.

There are faint traces of small teeth in the edges of the mandibles, and in
what remains of the maxilla, but no large tooth is anywhere visible. The
posterior edges of the large jugular plates overlap the anterior portion of the
bones of the pectoral arch, which exhibit a reticulated sculpture, whose
meshes are elongated in the direction of the long axis of the bone.

The scales, of which about twenty-four series are visible, diverge from the
median line in the ordinary way. They are rhomboidal, and have an aver-
age short diameter of one-sixth of an inch; but they are somewhat larger on
the anterior part of the ventral surface, than on the posterior part of the same
surface, and at the side of the body than on the belly.

The angles of each scale (A, B) are slightly rounded off. Along the anterior
and the inner sides, from a third to two-fifths of the outer surface of the scale
is smooth, or marked only by radiating and concentric striz, being over-
lapped by the edges of the adjacent scales. The rest of the outer surface is
beautifully and variously sculptured. In the anterior part of the ventral
region the sculpture, for the most part, takes the form of strong, more or less
longitudinal, thick ridges; but, posteriorly, these become superseded by a
pitted or reticulated structure. The weaker parts of the scale breaking away
more readily than the others, their free margins often appear toothed or irregular.

No fins are distinctly definable in this specimen, but there is a broken patch
on the right side, where the right pectoral should have been, and a few fin
rays are traceable in the place of the left pectoral.

From the totally different views of the body presented by these two speci-
mens, the only points of comparison between them are furnished by the
scales, which exhibit a general correspondence in form and size, while the
middle ventral scales of the second specimen would leave impressions, not un-
like those visible on the matrix in the middle lateral region of the first speci-
men. It is certainly a little difficult to reconcile the thick and depressed form
of the second specimen, with the apparently much thinner and more compressed
figure of the first; but it must be remembered that of this specimen we have
only half, and that the direction in which pressure has been exerted may have
greatly modified the forms of both specimens.

Again, the impressions and the general aspect of the scales in the first
specimen do not tally exactly with what might be expected from the per-
fectly preserved corresponding organs in the second; but then it must be
recollected that the precisely corresponding scales in the two fishes cannot be
compared.

On the whole, although not by any means satisfied as to the specific
identity of the two fish, I think it better to‘assume it until further evidence
proves the contrary.*

* Since the above was written, I have seen specimens of Gilyptolemus in the collection of
Lord Kinnaird, at Rossie Priory, which leave no doubt on my mind as to the correctness of
this assumption. In one of these specimens the edge of the maxilla exhibits a single series
of small and slender teeth.

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DESCRIPTION OF THE FOSSIL REMAINS. 67

Phaneroplewron—Hvx.ey (Glypticus—Acassiz.) (Nov. Genus.) Pio VVE
Phaneropleuron Andersoni—Huvuxuxry. (Nov. Species.)

Of this new genus and species of Devonian fish, several fragments, now in
the Museum of Practical Geology, have been sent to me by Dr. Anderson; but
the most complete specimen, figured in Plate VLI., is in the collection of the
British Museum, where it lies in the midst of a group of fish which have been
regarded as Holoptychii, but which almost all, in reality, belong to this new
species. This specimen likewise, I understand, originally formed a part of
the collection of Dr. Anderson.

The specimen measures about twelve and a half inches in length, while its
depth nowhere exceeds two and a half inches. It is difficult to define the
posterior boundary of the head, but it appears to be about two inches long,
and its anterior contour slopes rapidly downwards to the sharp snout.

The boundaries of the cranial bones are not¢raceable. Their surfaces
are almost smooth, and wholly devoid of such sculpture as is exhibited by the
bones of the head in specimens of Holoptychius, in the same slab of sandstone.

The scales are exceedingly thin, and all that can be certainly made out of
their structure is, that they have a circular outline, and are marked only by
fine, close-set, radiating ridges. The lateral line takes a curved direction from
the occipital region downwards to the middle of the body, and then courses along
the middle line to the tail. Its scales exhibit a slight longitudinal elevation.

The pectoral fins are not visible in this specimen, but in another, traces of
them remain, and they appear to have been similar to the ventrals. The
latter are very remarkable. In the specimen under description that of the
right side only is visible. It is attached, seven inches behind the end of the
snout, by a base which is nearly half an inch brodd, and it attains a length of
23 inches. The central part of the fin is formed by a solid tapering axis
covered with small scales like those on the body, and the fine fin-rays are
disposed symmetrically along the anterior and posterior margins of this
central axis.

Ventral fins having the structure which has been described, were more or
less plainly discernible in several of the specimens of Phaneropleuron in the
collection of the British Museum.

The rays of the dorsal fin commence a little in front of the middle of the
back, and of the root of the ventral fin. They are at first very short, but
they gradually increase in length backwards, as the dorsal line of the body
falls away in the caudal region, so that the top of the fin remains throughout
nearly on the same level, and forms a line parallel with the longitudinal axis
of the fish. The most posterior part of the fin, which attains a height of 14
inch, is consequently the deepest.

No separation can be traced between the dorsal fin and the dorsal lobe of
the caudal, as which, in all probability, the posterior part of the dorsal should
be regarded.

The inferior lobe of the caudal measures close upon three inches in length,
and attains nearly the same depth posteriorly as the dorsal lobe, or posterior
end of the dorsal fin.

68 MONOGRAPH OF DURA DEN.

The extreme termination of the tail of this specimen is not well shown, but
it is clearly displayed in that figured in Plate V. Here the dorso-caudal fin ends
posteriorly in a steep truncated margin, beyond which the persistent noto-
chord is continued for nearly two inches. The inferior lobe of the caudal fin,
on the other hand, is continued very much farther backwards.

The narrow anal fin (Plate VI.) is attached 94 inches behind the snout; it
measures 24 in. in length, and is brush-like in form, being broader towards
the end than at the root, but tapering almost to a point at its free extremity.

The anterior end of the mandible of one specimen displays a strong conical
tooth, and there is evidence that Phaneropleuron Andersoni attained eighteen
inches in length.

The specimens figured in Plate V. and Plate VI. fig. 3, again, show far better
than that first described, those peculiarities in the internal organization of the
fish on which I have based its name. In the specimen figured in Plate V.,
the persistent gelatinous notochord has left an impression three-eighths of an
inch thick anteriorly, which continues straight, and of about the same thick-
ness, for seven inches and a half; it then bends up at an obtuse angle, and,
with a slightly concave superior contour, tapers to the extremity of the tail.

Above the notochord, from its anterior end to where it bends up, lie
numerous slender but well ossified neural arches and spines, which are so
bent as to be slightly convex posteriorly, slightly concave anteriorly. The
anterior ones are about an inch long, and are slightly expanded at both ends.

A series of shorter, interspinous bones, at most three-eighths of an inch
long, occupy the interspace between these and the base of the dorsal fin.
These bones also are slightly expanded at each end, and disappear posteriorly
at the bend of the notochord.

Below the notochord lie in confusion a number of curved, slender, well-
ossified ribs, one-twentieth of an inch in diameter, which cease to be traceable
posteriorly about five inches and a half from the anterior end of the specimen.

A second fragment exhibits the opposite face of the middle region of an-
other fish of about the same size as that just described. The dorsal fin dimi-
nishes anteriorly, the interspinous bones becoming shorter, but the neural
spines, retaining their curvature, become longer and stronger, and the ribs in-
crease in length.

A third fragment (Plate VI., fig. 3) consists of the anterior part of the body,
with the hinder region of the head, whose upper walls have disappeared,
leaving part of the opercular apparatus and of the pectoral arch. The ribs
diminish in length anteriorly, but they retain their characteristic forms and
their well-ossified structure.

Professor Agassiz originally called this fish Glypticus, but he did not de-
scribe it or define the genus, and as the name was already in use it must be
changed. The generic appellation which I have proposed expresses the most
striking character of the fish—the curious obtrusiveness, if I may so say, of
its ribs, arising from their complete ossification and the thinness of the scales.*

The affinity of Phaneropleuron with the typical celacanths is indicated not
only by its singular tail, but by its persistent notochord, by its lobate pec-

* Pavepds, weupor.

ata

Gs

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70 MONOGRAPH OF DURA DEN.

but in some specimens the lateral bones meet in the middle line in front of the
median one. The lateral bones have radiating striz on the posterior halves
of their outer surfaces. The anterior margin of each unites with the parietal
of its side, and then passes backwards and outwards, so as to form a large re-
entering angle with the postero-lateral edge of the parietal. Into this re-
entering angle, two bones, which would seem to represent the squamosal of
ordinary fishes, are fitted. A large, suborbitar bone extends from the post-frontal
to the maxilla, and forms the posterior boundary of the orbit. The pre-oper-
culum is a very considerable bone, which is attached to the parietal between
the squamosal and post-frontal; to the latter bone and to the suborbitar bone
by its concave anterior margin; to the representatives of the squamosal, and
to the operculum and sub-operculum, by its convex posterior margin, while
inferiorly it extends to the angle of the mouth. The operculum is a broad
bone, larger behind, where it is convex, than in front, where it is concave, and
much longer than it is deep. The inferior limits of the sub-operculum were
not distinct in any specimen I examined, but the bone appears to have been
deeper than long.

The rami of the lower jaw are stout and strong, and form a very broad,
almost semicircular arch. Two broad, triangular, jugular plates occupy the
middle of their interval, and are separated from the rami by a number of
smaller bony plates on each side. There is no median plate between the
anterior ends of the principal jugular plates.

The outer surfaces of the bones of the pectoral arch exhibit radiating ridges,
where they are not overlapped by the opercular bones.

The characters of the scales are well known. Those of the lateral line
exhibit a slight median elevation, and form a series which descends from
close to the occipital region downwards and backwards upon the sides of the
body, whose axis it very nearly follows in the caudal region.

A small triangular dorsal fin begins opposite the hinder edge of the root of
the ventral fin, and is situated a little behind the middle of the body. It is
separated by about the breadth of its own base from the commencement of
the dorsal lobe of the caudal fin,* which occupies nearly the posterior third
of the whole length of the body, and attains its greatest height about the
middle of its length. The caudal end of the body gradually tapers to a
point which is not at all bent upwards, and the ventral lobe of the caudal
fin, though rather shorter than the dorsal lobe, has the same depth. The
caudal fin consequently forms a very nearly symmetrical rhomboid, and is
not, in the ordinary sense, heterocercal. The anal fin is ‘rather larger than
the dorsal, and is separated by but a very small interval from the ventral
lobe of the caudal.

A wide space separates the ventral fins from the anal, the former being
situated just beneath the middle of the body. Each has a short, conical,
scaly stem, from either side of which long fin rays proceed.

* Sir Philip Egerton, in a valuable memoir recently read before the Geological Society,
expresses his belief that Holoptychius has two dorsal fins. I am very loath to controvert the
opinion of so experienced and skilful an observer, the more particularly as specimens of Ho.
loptychius with perfect tails are very rare, but the one or two complete examples I have
seen, leave no room in my mind for any other conclusion than that stated above.

DESCRIPTION OF THE FOSSIL REMAINS. raul

The pectoral fin is very much larger than the ventral, attaining to a
quarter of the length of the body. A solid axis, covered with small scales,
and tapering to a fine point at its extremity, traverses the whole length of
the fin, and has the comparatively short fin rays attached to its anterior and
posterior margin, as in Phaneropleuron.

The teeth of Holoptychius are, for the most part, short, straight, slender,
and conical; but the anterior part of the mandible of a specimen in the
Museum of Practical Geology, exhibits a long, slender, and somewhat recurved
tusk, more than twice as long as any of the other teeth. The surface of this
tooth presents a number of fine sharp longitudinal ridges. An outline of the
left ramus of this mandible, of the natural size, and a magnified view of the
tusk, are given in the woodcut. It will be observed that these teeth are
totally different from those of Rhizodus.

Diplopterus Dalgleisiensis.—AGASsiz. Pu. I. Fie. 4.

The specimens of this genus have now been found in the several suites of
rocks, from the lower Old Red to the upper Yellow Sandstone of Dura Den,
and likewise in the coal-measures. Like the Holoptychius, it is therefore of
vast geologic range, commencing and terminating with that strong bright
scaled family in the same early series of deposits. The specimens obtained
in Dura Den consist only of two portions, a head, which is quite perfect, and
the posterior part of the body. These were forwarded by me to M. Agassiz
in 1837, and returned labelled as ‘‘ Diplopterus, new species.”

The individuals of this genus are represented as being of great bulk, attaining
a length of several feet, slender, atid tapering in the body, and, from the size
and position of the fins, powerful swimmers. The head is comparatively large
and well proportioned in its divisional parts. The eyes are placed in the —
middle of the head, close on the median line, which are large, and surrounded
by strong osseous projections; and the frontlets, which form the top of the
cranium, are flat, narrowing between the eyes, and dilating before and behind.
The snout is rounded; and the teeth are placed in a simple dental cavity, are
destitute of folded detentition, and greatly resemble the teeth of the Poly-
pterus. ‘The branchiostic rays, which are multiplied in other fishes, are, in
the Diplopterus, as well as in the Polypterus, supplied by two strong and
large triangular plates, occupying all the under part of the throat, and com-
prised between the two branches of the under jaws. ‘These two moveable
plates are separated by the median line, and permitted the throat to dilate,
by imparting to it a great degree of solidity. The Dura Den fossil has this
arrangement of these thoracic plates entire and most beautifully preserved,
showing one by one their position and relations to each other.

_ The scales of the Diplopterus, like all the ganoid fishes of the period, are
extremely marked in their characters, and must have subserved important
purposes in the functions of marine life. These organs are comparatively
large, massive, and compact; in form they are rhomboidal, hooked or en-
grained by their oblique edges, and show a fine granulation caused by a
number of small holes opening on the surface. These probably are holes of

72 ; MONOGRAPH OF DURA DEN,

passage for the numerous minute sanguinary vessels which traverse the body,
and allow the scale to adhere to the epidermis or outer skin. When examined
through a microscope, the scales present a thick bed of enamel, under which
we find an osseous tissue, showing a very beautiful net-work, differing only
from the Polypterus in its greater development, and in many respects resem-
bling the scaly cuirass of the new genus Gyroptychius. ‘Two large, sharp-
pointed teeth project from the outer edge of the lower jaw, and there are also
distinct traces of several smaller teeth in the posterior margin.

This new species of diplopterus has been named the Dai-
gleisiensis, in honour of the much respected proprietors of
the rich fossiliferous deposit of Dura Den, whose kindness to
all who visit the locality is so justly appreciated, and whose
liberality in distributing specimens among our public museums
and the private collections of the scientific is so beneficially and
widely experienced.

A single tooth of Dendrodus, it remains only to be noticed,
is all of this genus yet detected in the Dura sandstone. It
measures about an inch in length, and is nearly a fourth part
of an inch broad at the root. It is sharp-pointed and curved
downwards, and hollow in the posterior end. It is figured in
Fife Ilustrated, along with other characteristic fossils of Dura
Den. Several scales of Phyllolepis concentricus have also been
discovered in the deposit, and one of them has been described
to me as being three inches in length by two in breadth. Nor
are coprolites of large size wanting to attest the existence of
perhaps creatures of still huger dimensions, and of more pre-
daceous habits. Still our list is large ; and whatever may be in
store for future explorers in this rich field of fossil research, our
numerous visits, extending now over a large period of time,
have been no less amply rewarded than they have been the
occasions of much delightful recreation — of many pleasing
hours in acquiring useful knowledge—of many opportunities
of cultivating and renewing agreeable friendships—and, above
all, of privileged times in deepening our feelings of admira-
tion for the works of the Great Divine Conrriver and Heap
OF ALL.

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GENERAL INFERENCES. fis:

CHAPTER V.

GENERAL INFERENCES.

1. THE position of the Yellow Sandstone. This we consider
to be clearly established both by its mineral relations and fossil
remains. Step by step the Devonian series is well defined, in
the order of superposition, from the Grampians into the opening
of Dura Den, where the Clashbennie red deposit immediately
underlies the yellow beds of the locality. There is no other
line of demarcation than what occurs among the divisions of
the series ; and it may be safely averred that, in no quarter of
the world yet examined is there a group of rocks similar to
those of Dura Den, unequivocally attested or asserted to belong
to the coal measures. But the FossiL REMAINS, in all their
types and characters, are clearly sufficient in themselves to
determine the question. The pterichthyan forms are only
found in the middle series of the Old Red, while the numerical
abundance of the holoptychian tribe, in conjunction with so
many allied fishes, all of the ganoid granulated scale order,
establish relations up and down through the whole Devonian
system that must satisfy the most scrupulous inquirer on the
point at issue. Dura Den yellow sandstone, in its geognostic
position, mineral qualities, and fossil organisms, vindicates the
claim to be ranked among the rocks of the great Fish Epoch
rather than to be allied with those which enclose the flora of
the succeeding age of gigantic vegetables and mountain chains
of shelly limestone,—not a shell or vestige of plant being any-

74 MONOGRAPH OF DURA DEN.

where found in the whole composite mass, nor in any one of
the numerous quarries in the district.

2. What constitutes a geological formation, and how are the
limits to be determined? Here, in the yellow sandstone alone,
the fossil remains consist of nine genera and of eleven species,
namely : Pamphractus Andersoni (pterichthys), Holoptychius
Andersoni and Flemingii, Platygnathus Jamesoni and Minor,
Glyptopomus Minor, Glyptolemus Kinnairdi, Phaneropleuron
Andersoni, Diplopterus Dalgleisiensis, Phyllolepis Concentricus,
and Dendrodus (?). Two of the genera are common to the Old
Red and the Carboniferous systems, Holoptychius and Dzplo-
pterus. Three of the genera are found in the Lower and the
Upper series of the Old Red, Pterichthys, Platygnathus, and
Diplopterus. Three genera are common to the Middle series
of Morayshire and Clashbennie, and the Upper series of Dura
Den, Dendrodus, Phyllolepis, and Diplopterus.

The determination of a geological formation or system,

according to this list, cannot be made exclusively to depend
upon the specific, nor even upon the generic forms of organic
remains included in a series of rocks. The holoptychius and
diplopterus belong to two different formations, and pterichthys,
platygnathus, and diplopterus range from the lowest to the
highest beds of the Old Red strata. Will independent suites
of rocks, included in the same or in different formations, serve
for the determination of specific distinctions? Suppose a dis-

position to exist among paleontologists to merge four species

of holoptychius into one and the same, namely, Holoptychius
Murchisoni, nobilissimus, Anderson, and Hlemingi, what amount
of consideration would be due to their several positions in the
systems in which they are respectively included? M. Agassiz
asserts that he does not know a single species of fossil fish
which is found successively in two formations, while he is
acquainted with a good number which have a very considerable
horizontal extent.*
* Hdinburgh Philosophical Journal, p. 175.

GENERAL INFERENCES, 75

The question has been raised with regard to vegetable fossils,
and some interesting results have been brought out. Sir HH. de
la Beché relates* that it has for some time been held by conti-
nental geologists, that plants similar to those in the coal-mea-
sures are discovered in the Silurian strata. M. Burat asserted,
in 1834, that fossil vegetables, consisting of reeds and ferns,
found in the upper grauwaké (Silurian) are analogous to those
found in the coal-measures. M. Omalius de Halley also men-
tions the remains of carboniferous plants as occurring among
the transition slates of Ardennes. Professor Lindley noticed
a Stigmaria ficoidas, one of the commonest of our coal-field
organisms, in the upper grauwaké of Brittany, at St. George’s,
Chatellaison, and Montrelais, as well as at Bitchweiler in the
department of the Upper Rhine. In a very recent memoir on
the nature of the plants which have existed on the surface of
the earth at different epochs, M. Adolphe Brongniart} observes
that there does not appear to him more difference in the fossil
plants of the rocks earlier than the coal-measures, as compared
with those of the latter epoch, than there occurs between the
plants in the upper and lower beds of the coal formation itself.

Nor do animal fossil remains appear to be more restricted
in their range up and down among the rocks. Thus, it is
asserted{ that fossils belonging to the mountain limestone are
got in red sandstone in the river at Kildress in Tyrone, in the
middle, as well as near the bottom, of the Old Red Sandstone
system of that county. After a tabular statement of “the
North Devon, Silurian, and the Irish carboniferous localities,”
Mr. Kelly in the same paper records,§ “as may be seen by this
little table, many of the fossils are common to the grauwaké
and to the carboniferous systems. Out of the siaty-three species
recorded in the Silurian rocks of North Devon, thirty occur also
im the Carboniferous limestone of Ireland, and its underlying

* Geo. Re. on Cornwall, p. 132.
+ M. A. Brong. Mém. del’ Acad. Roy. des Sc., 11th Sept. 1839.

+ John Kelly on the Carboniferous Rocks of Ireland, p. 27, 1859.
@ Page 53,

76 MONOGRAPH OF DURA DEN.

calciferous slate, those thirty being all taken from Mr. M‘Coy’s
determination of the specimens submitted to him. Seven of
those which I have noted out of the sixty-three, are of the
most common kinds found in the Irish carboniferous limestone
system.” Instances of the same kind occur up and down
among all the systematic divisions, showing how Nature carries
forward her great progressional types with exceptional cases
in every epoch.

But still, with all these interpolations in paleontological
reading, it is convenient to have respect to lithological sub-
divisions, as already established on the greater scale of the
Silurian, Devonian, and carboniferous formations. Throughout
the great straths and valleys of Scotland the lines of demarca-
tion are generally well defined, and with no system of rocks
are they seen in finer relief than in those of the Old Red.
From the primary rocks of the Grampians to the Lomonds,
with successive anticlinal and synclinal dips, the outcrops of
every series are clearly traced ; the prevailing kinds of fossils
are persistent in the general suites of strata ; and, closing up
with the yellow sandstone of Dura Den, their mineralogical
characters all bear a family resemblance to one another, and to
the normal type of which the Devonian consists. The infinite
variety of mineral strata, especially, that build up the carboni-
ferous system ; the vast masses of lime, iron, and coal repeatedly
alternating with each other ; and the astonishing profusion of
details manifest in all the arrangements, are indicative of such
cosmical changes and conditions to which no former period of
the geological history of our globe bears any resemblance ;
and if Nature did from time to time cast off a few of her
typical specimens, and distribute them widely over sea and
land, as traced in the vertical superposition of the rocks, her
great divisional epochs, organic and inorganic, are not the less
strikingly marked and numbered. A remarkable class of
fishes, with a wide distribution and prolific development,
characterizes the epoch of the Old Red Sandstone ; and from

GENERAL INFERENCES. a

the lowest Caithness beds to the upper sandstone of Dura Den,
in which several of the species reach the culminating point of
size and numbers, the whole intermediate suites of strata
contain more or less of the prevailing ichthyological fauna, and
are conveniently therefore grouped into one great geological
system.

3. The clearly defined arrangements in the locality of Dura
Den and neighbouring district, may be studied with advantage
in working out the details of the system in other quarters.
The discussions, more especially in Ireland, respecting the car-
boniferous and yellow sandstone deposits, may be greatly
aided by an examination of the rocks in question. The term,
“yellow sandstone,” I observe, is employed by Sir R. Griffith,
Jukes, and Kelly, indifferently to denote all the variety of
yellow-whitish rock embraced within the coal-measures. By
Scottish geologists it is restricted to the upper series of the
Old Red exclusively, and from shore to shore over Scotland,
with intermixtures of reddish marls, the prevailing colour is
yellow. The position in Ireland of a sandstone of the same
mineralogical features is identical with the rock of Dura Den,
and bed by bed, as described by Mr. Kelly, they occupy pre-
cisely the same identical relations to each other. “In the
carboniferous formation there are two black or grey shales,—
one below the main mass of the limestone, called carboniferous
slate, one above it called millstone grit, or, as it is sometimes
called, coal shale, because, in this country, it forms the base of
the coal-measures. There are two sandstones also, the Old
Red below, the top of which is yellow or white, and the sand-
stone of the coal measures above, which consists of several
bands, and which are also yellow or white, and separated by
black shales.”*

This is precisely the colour, nature, and relations of the
beds in Dura Den, and in all the adjoining range east and
west along the lines of junction. Nor is the identity con-

* Page 4.

78 MONOGRAPH OF DURA DEN.

fined to these points alone. The dip, inclination, and general
bearing of the strata are perfectly similar. “In the district
between Drumquin and Pettigo, we have the whole of the con-
stituent rocks of the carboniferous formation ; on the north the
Old Red Sandstone, succeeded on the south by the calciferous
slate and mountain limestone, and these again by the black
shale, all with regular dip and in regular succession ;’* the
beds dipping mostly south-east and at a small angle, and in
the same stratigraphical arrangement. The thickness of the
yellow rock at the top of the Old Red is represented from
50 to 100 feet in Sligo and Mayo; in the King’s and Queen’s
counties, it is from 200 to 500 feet, and in Galway and Clare,
“the yellow colour prevails altogether, and the thickness of the
red beds near the base is only about fifty feet.”

The faults, dislocations, and intrusions of the igneous rocks
are, however, so numerous and deranging everywhere in the
Old Red and coal-field districts of Ireland, that any attempt to
work out the geology of any one of the systems by the succes-
sion and other peculiarities in the strata alone, is extremely
difficult, and perhaps scarcely practicable. The discovery of
organic remains, of the Dura Den type, would greatly facilitate
the solution of the points at issue, and I have little doubt, from
the large-scaled Holoptychius Portlocka found in the beds at
Cultra, that they may yet be detected in abundance in the
subjacent strata in the vicinity. Paleoniscus scales, and rays
and teeth of Gyracanthus, are everywhere abundant in the
ironstone shales in Fifeshire ; and a few miles to the eastwatd
of Dura Den, at Mount Melville near St. Andrews, large jaw-
bones with teeth of great size and in the most perfect state of
preservation, along with bright enamelled scales and other
relics, are very numerous.

4. Have we evidence to determine whether these are marine
or lacustrine deposits, and of what aqueous habits were the
fishes under review? Professor Huxley, ‘“‘ On Cephalaspis and

* Pp. 18, 21, et passim.

GENERAL INFERENCES. 79

Pteraspis,’* says that ganoid fishes are distinguished from all
others by certain peculiarities which are connected with the form
of the commissure of the optic nerves, the aorta, branchie, the
intestines, and the ventral fins. “These essential characters,” as
described in the paper, “are shared by only six genera of existing
fishes, Lepidosteus, Polypterus, Amia, Acipenser, Scapirhynchus,
and Spatularia, which are no less singular in their distribution
than in their anatomy. All are essentially fresh-water fishes ; all
are found in the northern hemisphere ; three— Lepidosteus,
Amia, and Spatularia, are exclusively North American ; Poly-
pterus is only known in the rivers of Africa, while Acipenser is
common to Europe, Asia, and North America,” The palzon-
tological ganoids are no less extensively distributed, prevailing
wherever the Old Red Sandstone is found, all over the north of
Kurope and America, the central regions of Asia, and other
quarters of the globe.

But, on the other hand, says Mr. Page,t looking at the whole
system of the Old Red Sandstone, both in point of time and
composition, we are prominently reminded of marine condi-
tions—“ of sea-shores whose sands formed sandstones, and of
beaches whose gravel was consolidated into conglomerates and
puddingstone—of receding tides that produced ripple-marks,
and of showers that left their impressions on the half-dried
silt of muddy estuaries.” Shall we add, that the vast and
world-wide geographical extent of these deposits confirm the
marine theory of their origin, since we can scarcely suppose
fresh-water lakes of co-ordinate dimensions at any time existing
on the face of the planet? But, again, when we examine the
fossil vegetable remains enclosed in the strata, and these most
abundant not among the littoral grits and breccia, but in the
tilestones and finest micaceous beds inferring deep-water for-
mation, we are constrained to recognise the existence of marshes
and river-banks which gave birth to a growth of ferns, trees,
and shrub-like plants; and of estuaries and fenny lagoons,

* Quart. Journ. Geol. vol. iy. p. 279. + Advanced Text-Book of Geology, p. 133.

80 MONOGRAPH OF DURA DEN.

where frog-like reptiles enjoyed the necessary conditions of an
amphibious life.

The following is from an extensive and excellent Paper of
R. Godwin-Austen, Esq., on the coal-measures beneath the
south-eastern part of England. in the Quarterly Journal of the
Geological Society of London for February 1856 :—

“ Much confusion in the chronology of geological changes has been caused
by the reference of this formation to the marine series. If due weight be
allowed to the facts of an accompanying terrestrial and fluviatile vegetation,
to the occurrence of the genus Cyclas, together with air-breathing oviparous
quadrupeds and terrestrial Chelonians, the early suggestion of Dr. Fleming,
though based on other considerations, will surely be adopted; and the Old
Red Sandstone of Scotland will be referred to the lacustrine series of forma-
tions. The ‘Old Red Sandstone’ fishes offer a subject well worthy of special
treatment, with reference to the conditions of the area of water in which they
lived; but the conclusions would probably be in accordance with those of
Dr. Mantell ; that these conditions were such as those of the Lepidosteus and
Polypterus.

“Of the three divisions into which Sir R. Murchison divided thie ‘ Old
Red Sandstone’ series of the Welsh area, the lowest or ‘ Tilestone group,’
which alone contains the remains of marine forms, has been since very gene-
rally referred to the ‘ Upper Ludlow’ deposits. The two higher divisions
alone represent the typical ‘Old Red Sandstone ;’ of these the argillo-calea-
reous or ‘ Cornstone’ group contains just such an assemblage of fishes as is
met with in the paleozoic fluvio-lacustrine deposits of Scotland ; whilst the
upper or ‘conglomerate and sandstone group,’ which as yet has only afforded
the remains of a Holoptychius, includes somewhat abundantly the spoil of a
terrestrial surface. On such considerations the ‘Old Red Sandstone’ of Here-
ford, Monmouth, and Somerset becomes the representative of another fresh-
water area, the relation and extent of which are indicated in the accompanying
Map (Pl. I.) Had not the true character of these two peculiar assemblages
of depositions been misapprehended, the creation of a ‘Devonian System’
would not have been needed.

“There are traces of ‘Old Red Sandstone’ at intermediate places between
the two great areas of Wales and Scotland; and these are of interest, as they
indicate with equal clearness an immediate subordination to a terrestrial sur-
face. The little patches which are dotted along the eastern skirts of the mass
of the old slate mountains of Westmoreland and Cumberland are in every case
so closely related to the rocks of the particular locality, as to suggest that they
are the alluvial beds of the ancient valley-courses of that region. A like local
relationship, as was long ago observed by M. Boué,* is to be traced along the
whole of the junction-line of the ‘Old Red Sandstone of Scotland ;’ and here
the accumulation often parts with its character of water-rounded conglomerate,
and assumes that of the angular talus so common in subaérial detritus.”

* Géol. de lV Heosse.

eee

GENERAL INFERENCES. §1

The solution of the difficulty will not be advanced by a con-
sideration of the remarkable contrasts exhibited throughout the
series of the deposit, inclusive of the lower and the upper beds
of Caithness and Dura Den, where the more characteristic
features of Animated Nature in the ancient period present the
most striking resemblances to the existing condition of things,
terrestrial and marine. Thus there are the large lobster-like
forms of Balruddery in contrast with the small shrimps of Res-
wallie, the huge Stagonolepis of Elgin to confront with the
crab-like pterichthyan fossils of Carmylie and Dura Den, the
mail-clad massive holoptychius of Clashbennie with the kampe-
caris or caterpillar-like appearance, occurring in shoals in the
Forfarshire flagstones, and the great cyclopteris or tree-fern, so
abundant in the system in Ireland, with the small berry-shaped
impressions of Parkhill and Tealing.

5. Have we any means of ascertaining the amount of Time
that may have lapsed during the accumulation of the materials
of the Old Red Sandstone series, or of any of the geological
- formations? The question has many aspects and_ bearings,
and there are many agencies concerned in the solution of the
problem.

Looking at the current operations of the laws of Nature,
and supposing their uniformity in past ages, a scale of incre-
ment is laid down for the several deposits of which the whole
crust of the earth is composed. An approximation is thus
attempted as to the number of years required for each, and
the result is, that the geological estimate embraces an incon-
ceivably lengthened and bewildering series. The calculation
proceeds not by hundreds, or even thousands, but by millions
of the terms of our numerical notation ; and as the fossiliferous
strata alone are reckoned at an average of ten miles in thick-
ness, the time that has elapsed since the appearance of LIFE
upon the planet has also been made a subject of investiga-
tion, including myriads of the brief fleeting years of man’s
existence.

82 MONOGRAPH OF DURA DEN.

But the position in the rock of the Dura Den fossils leads
clearly to the conclusion that they were suddenly and simul-
taneously imbedded in the sands and the silts of the period.
Their numbers, entireness, and general state of preservation,
evidently show that they have been overtaken by one and the
same cause of destruction, and instantly dropped to the bottom
of the waters. There is never a broken fin, nor a scale dis-
placed upon any of the specimens. They have not been
carried from a distance, nor rolled about for any length of
time. Everything indicates an immediate enclosure in their
soft sandy sepulchres, and, consequently, a rapid process of
silting up in the depths to which they sank. But for hundreds
of feet in the vertical thickness, up and down through the
rock, not a fragment or scale of a fish is detected. The mass
is completely non-fossiliferous, although consisting of several
varieties of materials, such as clays, marls, fine arenaceous
bands, and gritty beds.

No long period, therefore, we may justly infer, could have
elapsed during the progress of accumulation, as within a given -
amount of time many creatures must necessarily have perished,
and their remains been enclosed in the rocky mass. The
absence of fossils in a hundred feet of sandstone would warrant
the conclusion, from their natural term of existence, that
nothing like hundreds of years were spent in the accumulation
of the materials of the rock. And as with one series of the
formation, the same conditions, as we actually find them in
the lower series through immense depths of non-fossiliferous
strata, justifies the inference as to the proportion of the
element of time involved in the problem of their lithological
antiquity.

There is another test of considerable value, furnished by the
fossil trees in the sandstones of the Carboniferous formation
around this district, by which to ascertain the rate of accumu-
lation in the materials of these rocks. The action of currents
in every case must be admitted as necessary for conveying the

GENERAL INFERENCES. 83

muds, sands, and gravels of which the different beds consist ;
and the same agency that washed in the rocky matter would
likewise convey the trees and plants so abundantly diffused
through the mass. Fossilized trees, stems, and branches are
very numerous in every coal-field. They are often traced
through several layers of strata, in an upright position, or but
little inclined to the plane of stratification. The quarries on
Blebo hill, at a height of six hundred feet, and directly super-
incumbent on the yellow sandstone of Dura Den, are full of
these interesting relics,—large masses of stigmaria, sigillaria,
coniferee, and other species of trees, and lying in every position
in the sandstone, from the horizontal to the vertical. Many of
the imbedded trees in the coal-measures of the district, from
the Castle-rock of St. Andrews to the highest slopes of the
Lomonds, are of great length, and carried into the depths or
shallows, might often stand hundreds of feet above the waters.
A fossilized tree was exposed in the carboniferous sandstones
of Blair-Adam in the summer of 1857, in an upright position,
the roots entire, and spreading in all directions around, about
fifteen feet of stem in length by four to five feet in diameter,
and the carbonized bark adhering over the exposed section.
This tree originally might measure from two to three hundred
feet in height ; and whether, in or out of the waters, in part or
in whole, the woody mass could not long resist the destroying
action of the elements—the currents, waves, winds, and other
atmospheric agencies of the period.

Fossil trees of gigantic dimensions were, a few years ago,
dug out of the quarries of Craigleith and Granton, the roots
and some of the branches attached to the stem, and lying at
an angle of about twenty degrees to the horizon, as well as
the strata in which they were imbedded. The Purbeck “ dirt-
beds,” or old terrestrial surfaces and soils, contain at different
levels erect trunks, and stumps of conifere and cycads, with
their roots all attached and zn situ. At Beadnell, Northumber-
land, large areas in the coal-measures are covered with roots

84 MONOGRAPH OF DURA DEN.

and trunks, passing through several bands of shale and sand-
stone ; and to come to more recent times in the earth’s history,
there is a remarkably curious record of a clump of petrified
trees in a rocky passage of the Cordillera in the Uspallata
range of South America. Eleven of the trees are silicified,
and from thirty to forty are converted into coarsely crystallized
white calcareous spar ; the trunks are from three to five feet
in circumference, abruptly broken off and projecting several
feet above the ground. The sandstone in which they are
imbedded, and from which they must have sprung, has been
accumulated in successive thin layers around their stems,
retaining the impression of the bark, and now raised amid
enormous masses of volcanic rock seven thousand feet above
the level of the valley.

“Tt required little geological practice,” says Darwin, “to interpret the
marvellous story which this scene at once unfolded ;* though I confess I was
at first so much astonished that I could scarcely believe the plainest evidence
of it. Isaw the spot where a cluster of fine trees had once waved their
branches on the shores of the Atlantic, when that ocean—now driven back
700 miles—approached the base of the Andes. I saw that they had sprung
from a voleanic soil which had been raised above the level of the sea, and
that this dry land, with its upright trees, had subsequently been let down to
the depths of the ocean. There it was covered by sedimentary matter, and
this again by enormous streams of submarine lava,—one such mass alone
attaining the thickness of a thousand feet; and these deluges of melted stone
and aqueous deposits had been five times spread out alternately. The ocean
which received such masses must have been deep; but again the subterranean
forces exerted their powers, and I now beheld the bed of that sea forming a
chain of mountains more than 7000 feet in altitude. Nor had those anta-
gonist forces been dormant which are always at work to wear down the
surface of the land to one level ;—the great piles of strata had been inter-
sected by many wide valleys, and the trees, now changed into silex, were
exposed projecting from the voleanic soil now changed into rock, whence for-
merly, in a green and budding state, they had raised their stately heads. Now
all is utterly irreclaimable and desert ; even the lichen cannot adhere to the
stony casts of former trees. Vast and scarcely comprehensible as such changes
niust ever appear, yet they have all occurred within a period recent when
compared with the history of the Cordillera; and that Cordillera itself is
modern as compared with some other of the fossiliferous strata of South
America.”

# Journal of Researches, by Charles Darwin, Esq., F.R.S., p. 406.

GENERAL INFERENCES. 85

These instantie crucis may be multiplied and extended to
every sedimentary deposit in which fossil trees are found, and
an estimate derived of the formative process of the rocky
mass, layer after layer, from the duration of time that a tree,
standing in water, was able to preserve its structure and
resist the destroying action of the elements. Look at any of
the nearest river embankments, margined by trees, during the
season of floodings or overflows. Observe the oak, the hardest
specimen of our forests, engulfed in the waters, and then con-
sider the plain question, How many years, or months, or days,
will that noble stem and those giant branches be able to bear
themselves aloft, and laterally, or uprightly 4? or how long be
able to contend with the currents and other wasting agencies,
atmospheric and otherwise, by which they are assailed 4 Cer-
tainly not tens nor twenties—most assuredly not hundreds of
years—far less the thousands registered in the calendars of the
geologist! If the silting process is to be gauged by the
enduring powers of wood immersed in water, it is not perhaps
too much to say, that all the yellow sandstone rock of Dura
Den might have been collected, and piled bed upon bed, in a
shorter period than has been occupied in eroding and scooping
out the ravine itself by the action of the stream on the now
consolidated mass.

We have a remarkable instance of rapid formation, by sedi-
mentary and volcanic processes, in the island of Mull, where
huge mountains of basalt have been formed and upheaved
within comparatively recent times. The headland of Ardtun
shows in a vertical cliff of several hundred feet in height,
alternating beds of basalt, tuff, pumice or scoriz, and ligneous
mud, all indicating that the island and district were the theatres
of great volcanic action during the tertiary age. This inter-
esting discovery was made by the Duke of Argyll, who, in a
paper published in the Geological Quarterly Journal for May
1851, adduces clear and satisfactory evidence of vast sub-
terranean operations in Mull and the other western isles, and

86 MONOGRAPH OF DURA DEN.

at Antrim and the Giant’s Causeway, where alternating leaf-
beds and lignites are repeatedly mixed up with amorphous
and columnar igneous rocks. The account serves to establish
the important geological inferences, that Scotland and Ireland
were at the period of the eruptions parts of one and the same
country ; that the Hebrides and mainlands were united on
both sides; and that all the marine interspaces were over-
flowed by volcanic mud and ashes, which embraced, season
after season, the annual sheddings of a forest vegetation.
After describing the characters of the lignites and organic
remains, and the igneous mass of basalt rock in which they
are imbedded, the noble author proceeds to observe :—

‘No one who has followed this description of the Ardtun Head, the
‘ Point of Waves,’ and is acquainted with Staffa, will fail to recognise a re-
markably corresponding feature. The lowest two members of the Ardtun
series, the massive amorphous basalt, passing into and resting upon the
columnar, offer a precise representation, on a smaller scale, of that wonderful
front which lies opposite, at some five or six miles’ distance. ‘lhe whole
group of the Trishnish Islands, ‘which guard famed Staffa round,’ would
seem, from their low tabular appearance, to belong to the same prolonged
sheets of trap, and may represent the skeleton of that country now destroyed,
from whose forests the Ardtun leaves were shed. It is not improbable that
by future researches amid the conglomerates, and other stratified matters asso-
ciated with the traps, in Mull and the neighbouring islands, portions of the
more substantial parts of those forests will yet be found. It appears, from
Dr. M‘Culloch’s account of the traps of the middle district of the island of
Mull, that he did actually find the carbonized stem of a tree, whose structure
proved to be coniferous. His notice of the ‘ vein’ in which it occurred is an
accurate description of the tuff which covers the leaves of Ardtun; but he
expressly says, that it occupied a perpendicular instead of a horizontal posi-
tion in the cliff; and the headland of Bourg seems to be indicated, although
not very clearly, as the locality.”

Geologists have long been acquainted with the surturbrand
beds of Iceland ; that is, bituminized wood embedded in the
igneous rocks of that volcanic island. The characters of the
two classes of phenomena are almost identical ; a sympathy
betwixt the localities is still maintained by the shocks of earth-
quake that, from time to time, reach our shores. Hecla is still
in fiery activity, casting up volcanic mud and ashes, and thus

GENERAL INFERENCES. 87

are we reminded of the comparatively short period of time, as
of the close proximity in distance, since volcanoes existed in our
own island, and their subterranean fires, which have only re-
treated a few hundred miles, melted materials sufficient to form
cones, to shatter and upheave mountains.

And if so, in the comparatively modern, how much greater
were the agencies at work and the changes effected in the older
days of the earth’s history? The bulk of dry land, compared
with water, was in the primary times of these cosmical arrange-
ments, perhaps only a twentieth instead of a third part, as now,
of the supermarine area of the globe. How infinitely greater,
therefore, the action of the waters over all the materials subject
to their disintegrating power ; whether upon the islands and
continents already elevated above their waves, or upon the
immense submarine tracts of rock just lifting up their peaks
and being raised into the air? Nor, in alluding to volcanic
products, can we fail to perceive how greatly inferior are all
the modern to those of the palzozoic ages ; the mountains of
the historic and the tertiary periods to those of the secondary
and primary, when all the loftiest ranges were bursting into
position—the great American Continent, not as now with a few
isolated cones, but rending all over as the mighty Andes, Cor-
dilleras, and Rocky Mountains were rising above the deep, and
acquiring outline ; and in every quarter of the globe, through
Asia, Africa, and Europe, when our great Alpine groups were
formed, and all the plutonic, erosive, and denuding agencies
were upon a scale of corresponding magnitude and force.

“Tt is true, indeed,” says an eloquent writer,* “ that Nature is constant
and regular in her operations; but if, in the short course of our experience or
of that of past observers, no variation may have been noticed in the uniformity
of her workings, it is that the little segment of her duration’s cycle over which
we and they have travelled, is but as a straight line, an infinitesimal element,
whose curvature can only appear when referred to a much larger portion of
her circumference. That besides the particular laws with which we are ac-

quainted, there have been others once most active, whose agency is now
either suspended or concealed, the study of the world must easily convince

* Dr. Wiseman’s Lectures, p. 154.

88 MONOGRAPH OF DURA DEN.

us. There were times, within the range of mythological history, when
volcanoes raged in almost every chain of mountains; when lakes were dried
up or suddenly appeared in many valleys; when seas burst over their
boundaries and created new islands, or retired from their beds and increased
old continents ; when, in fine, there was a power of production and arrange-
ments on a great magnificent scale, when nature seemed employed not merely
in yearly renovation of plants and insects, but in the production from age to
age of the vaster and more massive elements of her sphere,—when her task
was not confined to embroidering the meadows in spring, or to paring away
of shores by the slow eating action of tides and currents, but when she toiled
in the great laboratories of the earth, upheaving mountains, and displacing
seas, and thus giving to the world its great indelible features.”

The distinguished author of the Siuria has expressed his
views upon the same point in similar eloquent terms.

“ Ag well,” says Sir Roderick Murchison, “ might the naturalist, upon
witnessing the gigantic growth of the African or American forests, compared
with the pigmy stature of our trees, calculate that, if the oak has required its
hundreds of years to reach its strength, they must have been rooted for thou-
sands in the soil, as the geologist conclude, that so many myriads of ages
must have been requisite to give to the systems of rocks their consistency and
consolidation.” And again: “ The uniformitarian who would explain every
natural event in the earliest periods by reference to existing conditions of
being, is stopped at the very threshold of the palace of former life (none being
before Silurian) which he cannot deprive of its true foundations. Nature
herself, in short, tells him, through her most ancient monuments, that though
she has worked during all ages on the same grand principles of destruction
and renovation of the surface, there was formerly a distribution of land in
reference to the sea, very different in outline from that which now prevails.
That primeval state was followed by outbursts of great volumes of igneous
matter from the interior, the extraordinary violence of which is made manifest
by clear evidences. Fractures in the crust of the earth, accompanied by
oscillations that suddenly displaced masses to thousands of feet above or
beneath their previous levels, were necessarily productive of such translations
of water as to abrade and destroy solid materials, and spread them over con-
tinents to an extent infinitely surpassing any change of which the historical
era affords example. I could here refer to the works of Leopold von Buch,
Elie de Beaumont, Sedgwick, Studia, and numerous other geologists, for
countless proofs of this grander intensity of former causation, by which gigantic
masses were inverted, and strata forming mountains have been so wrenched,
broken, and twisted, as to pass under the very rocks out of whose materials
they were constructed. In the Alps there are signs of such former cata-
strophes, each of which resulted from convulsions utterly immeasurable and
inexplicable by any reference to those puny oscillations of the earth which
can be appealed to during the times of history.” *

* Sdluria. By Sir R. I. Murchison, D.C.L. Third edition, p. 523.

GENERAL INFERENCES. 89

If the rocks of Dura Den were formed during the epoch of
such violent agencies, we, therefore, conclude that the fishes
now embedded in their consolidated materials were suddenly
destroyed by one of the disturbances of the period, and that
their position as confined to a single bed furnishes an additional
proof of the rapid collection and silting up of the materials of
which the rocks themselves are constituted. Leibnitz, in his
Protogeia, has largely dwelt upon these points, which, although
geology in his time was in no ways systematized, are remark-
ably in harmony with the deductions of modern discovery ; in
his masterly sketch, especially of the leading geognostic canons
of the science, he successfully advocates the intensive energy
with which physical causes must have acted in primordial
times ; and considers that the disruptions and igneous accumu-
lations of the earth’s crust, from the disturbances communicated
to the incumbent waters, must have been accompanied with
diluvial action, the mazime secute mundationes, on the largest
scale and the most extensive results.

6. But upon any view of these interesting speculations, a
terrestrial flora, on a scale of magnitude incomparably greater
than any in modern times, was now preparing for economic
purposes, the uses and the wants of creatures yet to emerge in
long after-periods. The dense forests that were to supply the
materials of our coal-fields, and the heaths and other herbaceous
shrubs that were to secrete the metal in our ironstone, required
an extent of plains, uplands, and mountain slopes which must
have surpassed in extent all existing carse, strath, or highland
glen in “ Caledonia wild,” or anywhere in the British Isles.
The seas likewise were to undergo mighty changes, both in
their deep oceanic troughs and their more shallow littoral ar-
rangements. Submarine volcanoes, whose poisonous elements
destroyed these shoals of ganoid fishes, were now to eject
volumes of calcareous and muddy materials, out of which coral-
agency was to elaborate the mountain limestones, and in whose
soft banks the countless shell-fish of the period were to burrow,

90 MONOGRAPH OF DURA DEN.

and their remains to be afterwards enclosed in the shales and
breccias of the system. New shores likewise were to be formed,
new basins to be constructed, new boundary lines to be cast up
from below, and dry lands submerged from above, and a
mechanism of forces arranged underneath the crust whereby
to admit the successive deposition of marine, estuary, and
fresh-water detritus of which the coal-measures all over the
earth are so marvellously composed. Here is presented the
evidence of vast changes of physical condition and oscillations
of level, showing that as frequently as the successive strata
were deposited, so frequently did the seas swarm with their
teeming inhabitants, and the lands wave under a dense vegeta-
tion ; while as many times were there the repeated alternations
of lakes, estuaries, lagoons, and seas of deeper and sometimes
of shallower bottoms.

The peculiarity of this flora is the great number of the vas-
cular cryptogamic plants, which amount to two-thirds of the
species of vegetables discovered in the carboniferous deposits.
With these are associated a few palms, coniferee, cycadee, and
some species of plants allied to the cacteee and euphorbiace.
The ferns are the most prevailing types, large arborescent
kinds, of which several hundred, belonging to many genera,
have been determined. Many of the strata of shale are entirely
made up of carbonized fern leaves and stems closely pressed
together. The roof of a coal mine, when newly exposed, often
presents the most wonderful appearance, from the amazing
abundance of these most graceful of all plants, and the infinite
variety of leaves, branches, and stems that are displayed, some-
times in relief, sometimes impressed on the dark shining surface.
When the shale or stone is of a light colour, the contrast of the
black carbonized foliage renders the effect perfectly enchanting,
rivalling everything in the shape of sculpture, mosaic intaglio
tracery, or all that was collected of art in the most admired
compartment of the Crystal Palace. But most remarkable of
all, the plants of the coal-measures, from Greenland to Aus-

GENERAL INFERENCES. 91

tralia, from Vancouver’s Island in the far west, to the remotest
corners of Russia, in Eastern Asia, are possessed of one uniform
botanical character, the same species being found in every lati-
tude, all now allied to those only of tropical countries, and
when the denseness and luxuriance of an Indian jungle pre-
vailed in every clime.

A calculation has actually been made of the amount of woody
substance contained in a given quantity of coal.* The results,
which are highly interesting, are as follow: wood affords in
general about twenty per cent., and coal about seventy per
cent. of charcoal. Throwing out of the calculation the oxygen
and hydrogen, it must therefore have required three and a half
tons of wood to produce the charcoal contained in one ton of
coal. Suppose now a forest, composed of trees, every one of
which is eighty feet high—that the trunk of each tree contains
eighty cubic feet, and the branches forty—and it results, that
the weight of each will be about two and a quarter tons. Allow-
ing one hundred and thirty such trees to an acre, we have three
hundred tons of woody matter on that area of ground. Nowa
cubic yard of coal weighs very nearly one ton; a bed of coal
one acre in extent, and three feet thick, will contain about four
thousand eight hundred tons ; and hence one acre of coal, with
only one bed of three feet thick, is equal to the produce of nearly
two thousand acres of forest. But instead of one bed there is
an average of eight to ten in the coal-measures of Scotland,
with an average aggregate thickness of twelve feet of the pure
mineral substance ; in England, there is a much higher ratio ;
and in the vast coal basins of America it is higher still. We
leave the reader to pursue for himself the arithmetical enume-
ration and comparison which these data furnish ; and we may
simply ask him to consider what amount of forest, all the world
over, is now buried in these subterranean regions, shedding,
year after year, their leaves and fruits to fill up the dense bitu-
minous mass, and where the lands on which their mighty trunks

* Geology of Fife and the Lothians, p. 116, by C. Maclaren, Esq., F.R.S.E.

92 MONOGRAPH OF DURA DEN.

were sustained? These families are nearly all extinct, or, as
in the ferns, and club-moss, and horse-tail tribes, a stunted,
pigmy race; and faintly allied, in a few others, in the arbores-
cent kinds of the tropics, to the giant types of the coal age.
How few of us all, who are in the daily enjoyment of the bless-
ings, in a thousand forms, derived from our easy and abundant
supplies of this fuel, think of the long and singular processes by
which it was prepared, ages ago, in the laboratory of nature,
where the forests of primeval times, deprived of their watery
and volatile parts, but retaining all their combustible matter,
were stored up for our use in inexhaustible quantities, under
our feet, closely packed and walled in by a solid masonry of
rock! Twenty years have scarcely elapsed since Witham, a
Yorkshire gentleman, visited Edinburgh, obtained prepared
slices of our different coals from the late Mr. Nicol, lapidary,
placed them under the microscope, and revealed, for the first
time, in all their marvellous woody tissue, the structure and
composition of our combustible treasures.

But the wonders of our coal-fields are not half exhausted by
these disclosures. The chemists tell us that the ironstone and
black-band, which are co-extensive almost with the coal in
geographical area, have chiefly derived their metallic properties
from the residue of the same plants which furnished the bitu-
minous compound. Much of the iron, doubtless, resulted from
the decomposed rocks of an anterior period, and was washed
down by the rivers into the basins in which the coal materials
were collected. Part of it likewise would be cast out in the
plutonic products from the innumerable volcanic foci which
everywhere existed in the coal-measures. But as in the
bog plants of the present time, which form our peat mosses,
so charged with solutions of iron, in like manner in the
exuberant vegetation of the carboniferous age, it is affirmed,
that enough of the metal existed to form the ores of iron
with which the coal beds are everywhere accompanied. There
are at present, in Scotland alone, upwards of a hundred

GENERAL INFERENCES. 93

hot-blast furnaces in operation, each smelting at the rate of
sixteen to twenty tons of pig-iron daily, or about 6240 annually,
and thus yielding a total of 624,100 tons. The market price
for the article, in this crude condition, is now about £3 per ton.
Hence the annual value of metallic ore, extracted from the
coal-fields of Scotland, is £1,872,300, nearly two millions ster-
ling ; for a product which the flora of the age yielded, over and
above the still richer mines of the combustible elements of the
coal itself.

And yet there are circumstances connected with the
ingredients and physical arrangements of the coal-mea-
sures, more marvellous even than anything now stated. We
allude to the limestones, and more especially to the en-
crinital portions of the formation. This mass of calcareous
matter, often sixty feet thick, as at Silver Mine Quarry, near
Linlithgow, consists almost entirely of shells and skeletons of
other marine animals. This limestone is co-extensive with the
coal-measures throughout the world, feathering out and in
among the metals, often in the form of a vertical wall, separat-
ing the basins of one district from those of another, and more
generally underlying the coal-beds in such a manner, as at the
same time to constitute the outer lip or edges of the great
trough of the carboniferous formation. Encrinites are corals.
They belong to the same zoophytie class of creatures which are
now piling up the coral reefs in the Pacific. They are composed
of similar varieties ; they wrought after the same fashion ; they
made corresponding diversities, according to the conditions of
their ocean bed, of the ring, atoll, and lagoon structure of coral
reef; ang they left their skeletons to construct the vast moun-
tain limestone strata under consideration. These strata are
common to all parts of the world. They exist in Melville
Island, in Greenland, and in every coal territory washed by the
Northern Ocean ; and in like manner over the central and
southern hemispheres of the earth’s surface. Like the coal
plants, the polyps of the ancient seas were ubiquitous, abound-

94 MONOGRAPH OF DURA DEN.

ing in all climes, and simultaneously in every latitude, breasting
the ocean wave, and rearing up their massive courses of natural
masonry.

The coral classes are distinguished in the Linnean ar-
rangements into several genera, and the analogy as to size
and the products of their working, is here wonderfully main-
tained betwixt the extinct and the existing species of polyps.
As, for example, in the diminutive ferns, horse-tails, and club-
mosses of our northern latitudes, there are the allied families of
the tropical aborescent kinds in the largest forms of trees, so
among the tubipores, cellepores, and antipathes, now so active
and skilful in rearing their huge piles of coral reef in the tropical
seas, there are their representative species of Fascicula, Hydra,
and others, found on the shores of Greenland, and still plying
their pigmy functions amid the rigours of the Northern Ocean.
Thus nature clings to her types of animal as of vegetable life
through all time. Thus she enlightens our scepticism, and
removes our doubts, as to the surprising means by which she
accomplishes her purposes on the greater as on the smaller
scale ; and shows, by what she is doing now, through these
humble instruments, she has done ages ago, in constructing the
fabric of our earthy dwelling, and in storing the inner chambers
with the most valuable materials for our use and comfort. The
busy artisans that now rise upon the ocean surge, are one and
the same in nature, habit, and toiling aim, with those earlier
denizens of the sea whose wondrous structures rose above the
breakers, elaborating their food and their coral bed from the
elements of the same water, and manifesting their instincts as
the voice of the same God who commanded the waters, to bring
forth abundantly the moving creature that hath life.

“ Even as one essence of pervading light
Shines in the brightness of ten thousand stars,
And the meek worm that feeds her lonely lamp
Couched in the dewy grass.”

The mind that sees not in these singular operations evidences
of design, foresight, and purpose, can have no proper conception

GENERAL INFERENCES. 95

of the relative influence of cause and effect, of wisdom and con-
trivance. We have here a combination of materials in every
coal-field, rough and rude as all about it may appear, which
directly speaks to us of intelligent superintendence. These
things by accident or chance could not have happened. The
heavens declare the glory of their Author. A voice from the
deep places of the earth speaketh of His ways. Astronomy
unfolds the wonders and stability of the starry system. Geology
lays open the interior structure and the beautiful arrangements
of our own planet. One series of rocks only have we touched
upon. ‘To the eye of the common observer all appears confu-
sion and disorder—materials cast out and piled upon each other
at random, rocks upheaved and rent asunder according to no
method or law, and all within exhibiting the still more repulsive
features of sterility and death. The eye of science looks a
little deeper, where it sees order, symmetry, and a boundless
profusion of the richest materials, stored up ages ago for man’s
use and social advancement, affording sustenance and enjoy-
ment to earth’s varied tribes in far bygone times, and now these
stony chambers beneath, the Necropolis of its countless, long-
buried dead! The illustrious Bacon has beautifully said :
“ Philosophia naturalis, post verbum Dei, certissima supersti-
tionis medicina est ; eademque probatissimum fidei alimentum.”
How truly is this the case with geological researches as to the
“potestas Dei” of which he afterwards speaks, where the
arrangements, diversity, and constituent elements of the frame-
work of the globe present such manifest illustrations of the
power, wisdom, and goodness of Him who reared the stupen-
dous fabric, and made our humble dwelling-place one of the
bright rolling planets of the universe !

Who would refuse to study and examine into these things ?
What interesting disclosures are missed when we do! What
culpable, unpardonable neglect, or indolence, or prejudice, in
passing over knowledge so readily, and in every spot of earth’s

96 MONOGRAPH OF DURA DEN.

surface, acquired! The world long panted after what was
termed the philosopher's stone. The wonderfully transmuting
material has been discovered at last. There are two words,
containing only eleven letters, but expressive of the most
valuable minerals in the world—coauL and Diamonp. No two
minerals are more unlike, and yet essentially the same. The
one is bright and dazzling: the other black and forbidding.
The one sparkles on the brows of queens and nobles: the other
is every man’s comfort and a country’s wealth. Coal builds
towns and factories everywhere around it. It has bridged the
ocean; it has made a highway over the earth; and it will
become the civilizer of the world. The Christian missionary
will hail its beacon-light in the wilderness ; the solitary place
will be made glad by it; the Gospel message will speed along
the lines of its accelerating power. How curious the reflection,
that the present commercial greatness of Britain, and in which
all its noble philanthropic schemes are built up, should be inti-
mately connected with a black combustible mineral, the product
of arboraceous ferns and gigantic reeds—vegetables of strange
forms and uncouth names, which flourished and decayed on the
surface of the earth, age after age, ere the mountains in many
a land were yet upheaved—and plains and mountains, which
then towered aloft with their dense forests, are again engulfed—
and when as yet there was no man to till the ground! But
such truths geology teaches us, the lessons engraven as with a
pen of iron on the flinty rocks, and the readings as legible and
accurate as the print of yesterday.

EDINBURGH: T. CONSTABLE, PRINTER TO HER MAJESTY

MCZ LIBRARY
HARVARD UNIVERSITY
CAMBRIDGE. MA USA

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