"He who, with pocket hammer, smites the edge
Of luckless rock or prominent stone, disguised
In weather stains, or crusted o'er by nature
With her first growths--detaching by the stroke
A chip or splinter, to resolve his doubts;
And, with that ready answer satisfied,
The substance classes by some barbarous name.
And hurries on."--WORDSWORTH.
In the course of my two visits to Miss Dunbar, I had several
opportunities of examining the sand-wastes of Culbin, and of registering
some of the peculiarities which distinguish the arenaceous sub-aerial
formation from the arenaceous sub-aqueous one. Of the present surface of
the earth, considerably more than six millions of square miles are
occupied in Africa and Asia alone by sandy deserts. With but the
interruption of the narrow valley of the Nile, an enormous zone of arid
sand, full nine hundred miles across, stretches from the eastern coast
of Africa to within a few days' journey of the Chinese frontier: it is a
belt that girdles nearly half the globe;--a vast "ocean," according to
the Moors, "without water." The sandy deserts of the rainless districts
of Chili are also of great extent: and there are few countries in even
the higher latitudes that have not their tracts of arenaceous waste.
These sandy tracts, so common in the present scene of things, could not,
I argued, be restricted to the recent geologic periods. They must have
existed, like all the commoner phenomena of nature, under every
succeeding system in which the sun shone, and the winds blew, and
ocean-beds were upheaved to the air and the light, and the waves threw
upon the shore, from arenaceous sea-bottoms, their accumulations of
light sand. And I was now employed in acquainting myself with the marks
by which I might be able to distinguish sub-aerial from sub-aqueous
formations, among the ever-recurring sandstone beds of the geologic
deposits. I have spent, when thus engaged, very delightful hours amid
the waste. In pursuing one's education, it is always very pleasant to
get into those _forms_ that are not yet introduced into any school.
One of the peculiarities of the sub-aerial formation which I at this
time detected struck me as curious. On approaching, among the
sand-hills, an open level space, covered thickly over with water-rolled
pebbles and gravel, I was surprised to see that, dry and hot as the day
was elsewhere, the little open space seemed to have been subjected to a
weighty dew or smart shower. The pebbles glistened bright in the sun,
and bore the darkened hue of recent wet. On examination, however, I
found that the rays were reflected, not from wetted, but from polished
surfaces. The light grains of sand, dashed against the pebbles by the
winds during a long series of years--grain after grain repeating its
minute blow, where, mayhap, millions of grains had struck before--had at
length given a resinous-looking, uneven polish to all their exposed
portions, while the portions covered up retained the dull unglossy coat
given them of old by the agencies of friction and water. I have not
heard the peculiarity described as a characteristic of the arenaceous
deserts; but though it seems to have escaped notice, it will, I doubt
not, be found to obtain wherever there are sands for the winds to waft
along, and hard pebbles against which the grains may be propelled. In
examining, many years after, a few specimens of silicified wood brought
from the Egyptian desert, I at once recognised on their flinty surfaces
the resinous-like gloss of the pebbles of Culbin; nor can I doubt that,
if geology has its sub-aerial formations of consolidated sand, they
will be found characterized by their polished pebbles. I marked several
other peculiarities of the formation. In some of the abrupter sections
laid open by the winds, tufts of the bent-grass (_Arundo
arenaria_--common here, as in all sandy wastes) that had been buried up
where they grew, might be distinctly traced, each upright in itself, but
rising tuft above tuft in the steep angle of the hillock which they had
originally covered. And though, from their dark colour, relieved against
the lighter hue of the sand, they reminded me of the carbonaceous
markings of sandstone of the Coal Measures, I recognised at least _their
arrangement_ as unique. It seems to be such an arrangement--sloping in
the general line, but upright in each of the tufts--as could take place
in only a sub-aerial formation. I observed further, that in frequent
instances there occurred on the surface of the sand, around decaying
tufts of the bent-grass, deeply-marked circles, as if drawn by a pair of
compasses or a trainer--effects apparently of eddy winds whirling round,
as on a pivot, the decayed plants; and yet further, that footprints,
especially those of rabbits and birds, were not unfrequent in the waste.
And as lines of stratification were, I found, distinctly preserved in
the formation, I deemed it not improbable that, in cases in which high
winds had arisen immediately after tracts of wet weather, and covered
with sand, rapidly dried on the heights, the damp beds in the hollows,
both the circular markings and the footprints might remain fixed in the
strata, to tell of their origin. I found in several places, in chasms
scooped out by a recent gale, pieces of the ancient soil laid bare,
which had been covered up by the sand-flood nearly two centuries before.
In one of the openings the marks of the ancient furrows were still
discernible; in another, the thin stratum of ferruginous soil had
apparently never been brought under the plough; and I found it charged
with roots of the common brake (_Pteris aquilina_), in a perfect state
of keeping, but black and brittle as coal. Beneath this layer of soil
lay a thin deposit of the stratified gravel of what is now known as the
later glacial period--the age of _osars_ and moraines; and beneath
all--for the underlying Old Red Sandstone of the district is not exposed
amid the level wastes of Culbin--rested the boulder clay, the memorial
of a time of submergence, when Scotland sat low in the sea as a wintry
archipelago of islands, brushed by frequent icebergs, and when
sub-arctic molluscs lived in her sounds and bays. A section of a few
feet in vertical extent presented me with four distinct periods. There
was, first, the period of the sand-flood, represented by the bar of
pale-sand; then, secondly, the period of cultivation and human
occupancy, represented by the dark plough-furrowed belt of hardened
soil; thirdly, there was the gravel; and, fourthly, the clay. And that
shallow section exhausted the historic ages, and more; for the double
band of gravel and clay belonged palpably to the geologic ages, ere man
had appeared on our planet. There had been found in the locality, only a
few years previous to this time, a considerable number of stone
arrow-heads--some of them only partially finished, and some of them
marred in the making, as if some fletcher of the stone age had carried
on his work on the spot; and all these memorials of a time long anterior
to the first beginnings of history in the island were restricted to the
stratum of hardened mould.
I carried on my researches in this--what I may term the
chronological--direction, in connexion with the old-coast line, which,
as I have already said, is finely developed in the neighbourhood of
Cromarty on both sides of the Firth, and represented along the
precipices of the Sutors by its line of deep caves, into which the sea
never now enters. And it, too, pressed upon me the fact of the amazing
antiquity of the globe. I found that the caves hollowed by the
surf--when the sea stood from fifteen to five-and-twenty feet above its
present level, or, as I should perhaps rather say, when the land sat
that much lower--were deeper, on the average, by about one-third, than
those caves of the present coast-line that are still in the course of
being hollowed by the waves. And yet the waves have been breaking
against the present coast-line during the whole of the historic period.
The ancient wall of Antoninus, which stretched between the Firths of
Forth and Clyde, was built at its terminations with reference to the
existing levels; and ere Caesar landed in Britain, St. Michael's Mount
was connected with the mainland, as now, by a narrow neck of beach laid
bare by the ebb, across which, according to Diodorus Siculus, the
Cornish miners used to drive, at low water, their carts laden with tin.
If the sea has stood for two thousand six hundred years against the
present coast-line--and no geologist would fix his estimate of the term
lower--then must it have stood against the old line, ere it could have
excavated caves one-third deeper than the modern ones, three thousand
nine hundred years. And both sums united more than exhaust the Hebrew
chronology. Yet what a mere beginning of geologic history does not the
epoch of the old coast-line form! It is but a starting-point from the
recent period. Not a single shell seems to have become extinct during
the last six thousand years. The organisms which I found deeply embedded
in the soil beneath the old coast-line were exactly those which still
live in our seas; and I have been since told by Mr. Smith of Jordanhill,
one of our highest authorities on the subject, that he detected only
three shells of the period with which he was not familiar as existing
forms, and that he subsequently met with all three, in his dredging
expeditions, still alive. The six thousand years of human history form
but a portion of the geologic day that is passing over us: they do not
extend into the _yesterday_ of the globe, far less touch the myriads of
ages spread out beyond. Dr. Chalmers had taught, more than a quarter of
a century previous to this time, that the Scriptures do not fix the
antiquity of the earth. "If they fix anything," he said, "it is only the
antiquity of the human species." The Doctor, though not practically a
geologist at the time, had shrewdly weighed both the evidence adduced
and the scientific character of the men who adduced it, and arrived at a
conclusion, in consequence, which may now be safely regarded as the
final one. I, on the other hand, who knew comparatively little about the
standing of the geologists, or the weight which ought to attach to their
testimony, based my findings regarding the vast antiquity of the earth
on exactly the data on which they had founded theirs; and the more my
acquaintance with the geologic deposits has since extended, the firmer
have my convictions on the subject become, and the more pressing and
inevitable have I felt the ever-growing demand for longer and yet longer
periods for their formation. As certainly as the sun is the centre of
our system, must our earth have revolved around it for millions of
years. An American theologian, the author of a little book entitled the
"Epoch of Creation," in doing me the honour of referring to my
convictions on this subject, states, that I "betray indubitable tokens
of being spell-bound to the extent of infatuation, by the foregone
conclusion of" my "theory concerning the high antiquity of the earth,
and the succession of animal and vegetable creations." He adds further,
in an eloquent sentence, a page and a half long, that had I first
studied and credited my Bible, I would have failed to believe in
successive creations and the geologic chronology. I trust, however, I
may say I did first study and believe my Bible. But such is the
structure of the human mind, that, save when blinded by passion or
warped by prejudice, it must yield an involuntary consent to the force
of evidence; and I can now no more refuse believing, in opposition to
respectable theologians such as Mr. Granville Penn, Professor Moses
Stuart, and Mr. Eleazar Lord, that the earth is of an antiquity
incalculably vast, than I can refuse believing, in opposition to still
more respectable theologians, such as St. Augustine, Lactantius, and
Turretine, that it has antipodes, and moves round the sun. And further,
of this, men such as the Messrs. Penn, Stuart, and Lord may rest
assured, that what I believe in this matter now, all theologians, even
the weakest, will be content to believe fifty years hence.
Sometimes a chance incident taught me an interesting geological lesson.
At the close of the year 1830, a tremendous hurricane from the south and
west, unequalled in the north of Scotland, from at least the time of the
great hurricane of Christmas 1806, blew down in a single hour four
thousand full-grown trees on the Hill of Cromarty. The vast gaps and
avenues which it opened in the wood above could be seen from the town;
and no sooner had it begun to take off than I set out for the scene of
its ravages. I had previously witnessed, from a sheltered hollow of the
old coast-line, the extraordinary appearance of the sea. It would seem
as if the very violence of the wind had kept down the waves. It brushed
off their tops as they were rising, and swept along the spray in one
dense cloud, white as driving snow, that rose high into the air as it
receded from the shore, and blotted out along the horizon the line
between sky and water. As I approached the wood, I met two poor little
girls of from eight to ten years, coming running and crying along the
road in a paroxysm of consternation; but, gathering heart on seeing me,
they stood to tell that when the storm was at its worst they were in the
midst of the falling trees. Setting out for the Hill on the first rising
of the wind, in the expectation of a rich harvest of withered boughs,
they had reached one of its most exposed ridges just as the gale had
attained to its extreme height, and the trees began to crash down around
them. Their little tear-bestained countenances still continued to show
how extreme the agony of their terror had been. They would run, they
said, for a few paces in one direction, until some huge pine would come
roaring down, and block up their path; when, turning with a shriek, they
would run for a few paces in another; and then, terrified by a similar
interruption, again strike off in a third. At length, after passing
nearly an hour in the extremest peril, and in at least all the fear
which the circumstances justified, they succeeded in making their way
unhurt to the outer skirts of the wood. Bewick would have found in the
incident the subject of a vignette that would have told its own story.
In getting into the thick of the trees, I was struck by the
extraordinary character of the scene presented. In some places, greatly
more than half their number lay stretched upon the ground. On the more
exposed prominences of the Hill, scarce a tree was left standing for
acres together: they covered the slopes; tree stretched over tree like
tiles on a roof, with here and there some shattered trunk whose top had
been blown off, and carried by the hurricane some fifteen or twenty
yards away, leaning in sad ruin over its fallen comrades. What, however,
formed the most striking, because less expected, parts of the scene,
were the tall walls of turf that stood up everywhere among the fallen
trees, like the ruins of dismantled cottages. The granitic gneiss of the
Hill is covered by a thick deposit of the red boulder clay of the
district, and the clay, in turn, by a thin layer of vegetable mould,
interlaced in every direction by the tree roots, which, arrested in
their downward progress by the stiff clay, are restricted to the upper
layer. And, save where here and there I found some tree snapped across
in the midst, or divested of its top, all the others had yielded at the
line between the boulder clay and the soil, and had torn up, as they
fell, vast walls of the felted turf, from fifteen to twenty feet in
length, by from ten to twelve feet in height. There were quite enough of
these walls standing up among the prostrate trees, to have formed a
score of the eastern Sultan's ruined villages; and they imparted to the
scene one of its strangest features. I have mentioned in an early
chapter, that the Hill had its dense thickets, which, from the gloom
that brooded in their recesses even at mid-day, were known to the boys
of the neighbouring town as the "dungeons." They had now fared, however,
in this terrible overturn, like dungeons elsewhere in times of
revolution, and were all swept away; and piles of prostrate trees--in
some instances ten or twelve in a single heap marked where they had
stood. In several localities, where they fell over swampy hollows, or
where deep-seated springs came gushing to the light, I found the water
partially dammed up, and saw that, were they to be left to cumber the
ground as the debris of forests destroyed by hurricanes in the earlier
ages of Scottish history would certainly have been left, the deep shade
and the moisture could not have failed to induce a total change in the
vegetation. I marked, too, the fallen trees all lying one way, in the
direction of the wind; and the thought at once struck me, that in this
recent scene of devastation I had the origin of full one-half of our
Scottish mosses exemplified. Some of the mosses of the south date from
the times of Roman invasion. Their lower tiers of trunks bear the mark
of the Roman axe; and in some instances, the sorely wasted axe itself--a
narrow, oblong tool, somewhat resembling that of the American
backwoodsman--has been found sticking in the buried stump Some of our
other mosses are of still more modern origin: there exist Scottish
mosses that seem to have been formed when Robert the Bruce felled the
woods and wasted the country of John of Lorn. But of the others, not a
few have palpably owed their origin to violent hurricanes, such as the
one which on this occasion ravaged the Hill of Cromarty. The trees which
form their lower stratum are broken across, or torn up by the roots,
_and their trunks all lie one way_. Much of the interest of a science
such as geology must consist in the ability of making dead deposits
represent living scenes; and from this hurricane I was enabled to
conceive, pictorially, if I may so express myself, of the origin of
those comparatively recent deposits of Scotland which, formed almost
exclusively of vegetable matter, contain, with rude works of art, and
occasionally remains of the early human inhabitants of the country,
skeletons of the wolf, the bear, and the beaver, with horns of the _bos
primigenius_ and _bos longifrons_, and of a gigantic variety of red
deer, unequalled in size by animals of the same species in these latter
ages. Occasionally I was enabled to vivify in this way even the ancient
deposits of the Lias, with their vast abundance of cephalopodous
mollusca--belemnites, ammonites, and nautili. My friend of the Cave had
become parish schoolmaster of Nigg; and his hospitable dwelling
furnished me with an excellent centre for exploring the geology of the
parish, especially its Liassic deposits at Shandwick, with their huge
gryphites and their numerous belemnites, of at least two species,
comparatively rare at Eathie--the _belemnite abreviatus_ and _belemnite
elongatus_. I had learned that these curious shells once formed part of
the internal framework of a mollusc more nearly akin to the
cuttle-fishes of the present day than aught else that now exists; and
the cuttle-fishes--not rare in at least one of their species (_loligo
vulgare_) in the Firth of Cromarty--I embraced every opportunity of
examining. I have seen from eighteen to twenty individuals of this
species enclosed at once in the inner chamber of one of our
salmon-wears. The greater number of these shoals I have ordinarily found
dead, and tinged with various shades of green, blue, and yellow--for it
is one of the characteristics of the creature to assume, when passing
into a state of decomposition, a succession of brilliant colours; but I
have seen from six to eight individuals of their number still alive in a
little pool beside the nets, and still retaining their original pink
tint, freckled with red. And these I have observed, as my shadow fell
across their little patch of water, darting from side to side in panic
terror within the narrow confines, emitting ink at almost every dart,
until the whole pool had become a deep solution of sepia. Some of my
most interesting recollections of the cuttle-fish are associated,
however, with the capture and dissection of a single specimen. The
creature, in swimming, darts through the water much in the manner that a
boy slides down an ice-crusted declivity, feet foremost;--the lower or
nether extremities go first, and the head behind: it follows its tail,
instead of being followed by it; and this curious peculiarity in its
mode of progression, though, of course, on the whole, the mode best
adapted to its conformation and instincts, sometimes proves fatal to it
in calm weather, when not a ripple breaks upon the pebbles, to warn that
the shore is near. An enemy appears: the creature ejects its cloud of
ink, like a sharp-shooter discharging his rifle ere he retreats; and
then, darting away, tail foremost, under cover of the cloud, it grounds
itself high upon the beach, and perishes there. I was walking, one very
calm day, along the Cromarty shore, a little to the west of the town,
when I heard a peculiar sound--a _squelch_, if I may employ such a
word--and saw that a large loligo, fully a foot and a half in length,
had thrown itself high and dry upon the beach. I laid hold of it by its
sheath or sack; and the loligo, in turn, laid hold of the pebbles,
apparently to render its abduction as difficult as possible, just as I
have seen a boy, when borne off against his will by a stronger than
himself, grasping fast to door-posts and furniture. The pebbles were
hard and smooth, but the creature raised them very readily with his
suckers. I subjected one of my hands to its grasp, and it seized fast
hold; but though the suckers were still employed, it made use of them on
a different principle. Around the circular rim of each there is a fringe
of minute thorns, hooked somewhat like those of the wild rose. In
clinging to the hard polished pebbles, these were overlapped by a fleshy
membrane, much in the manner that the cushions of a cat's paw overlap
its claws when the animal is in a state of tranquillity; and by means of
the projecting membrane, the hollow interior was rendered air-tight, and
the vacuum completed: but in dealing with the hand--a soft
substance--the thorns were laid bare, like the claws of a cat when
stretched out in anger, and at least a thousand minute prickles were
fixed in the skin at once. They failed to penetrate it, for they were
short, and individually not strong; but, acting together by hundreds,
they took at least a very firm hold.
What follows may be deemed barbarous; but the men who gulp down at a
sitting half-a-hundred live oysters to gratify their taste, may surely
forgive me the destruction of a single mollusc to gratify my curiosity!
I cut open the sack of the creature with a sharp penknife, and laid bare
the viscera. What a sight for Harvey, when prosecuting, in the earlier
stages, his grand discovery of the circulation! _There_, in the centre,
was the yellow muscular heart, propelling into the transparent, tubular
arteries, the _yellow_ blood. Beat--beat--beat:--I could see the whole
as in a glass model; and all I lacked were powers of vision nice enough
to enable me to detect the fluid passing through the minuter arterial
branches, and then returning by the veins to the _two_ other hearts of
the creature; for, strange to say, it is furnished with three. There in
the midst I saw the yellow heart, and, lying altogether detached from
it, two other deep-coloured hearts at the sides. I cut a little deeper.
_There_ was the gizzard-like stomach, filled with fragments of minute
mussel and crab shells; and _there_, inserted in the spongy, conical,
yellowish-coloured liver, and somewhat resembling in form a Florence
flask, was the ink-bag distended, with its deep dark sepia--the
identical pigment sold under that name in our colour shops, and so
extensively used in landscape drawing by the limner. I then dissected
and laid open the circular or ring-like brain that surrounds the
creature's parrot-like beak, as if its _thinking_ part had no other
vocation than simply to take care of the mouth and its
pertinents--almost the sole employment, however, of not a few brains of
a considerably higher order. I next laid open the huge eyes. They were
curious organs, more simple in their structure than those of the true
fishes, but admirably adapted, I doubt not, for the purposes of seeing.
A camera obscura may be described as consisting of two parts--a lens in
front, and a darkened chamber behind; but in the eyes of fishes, as in
the brute and human eye, we find a third part added: there is a lens in
the middle, a darkened chamber behind, and a lighted chamber, or rather
vestibule, in front. Now, this lighted vestibule--the cornea--is
wanting in the eye of the cuttle-fish. The lens is placed in front, and
the darkened chamber behind. The construction of the organ is that of a
common camera obscura. I found something worthy of remark, too, on the
peculiar style in which the chamber is darkened. In the higher animals
it may be described as a chamber hung with black velvet--the _pigmentum
nigrum_ which covers it is of the deepest black; but in the cuttle-fish
it is a chamber hung with velvet, not of a black, but of a dark purple
hue--the _pigmentum nigrum_ is of a purplish red colour. There is
something interesting in marking this first departure from an invariable
condition of eyes of the more perfect structure, and in then tracing the
peculiarity downwards through almost every shade of colour, to the
emerald-like eye-specks of the pecten, and the still more rudimentary
red eye-specks of the star-fish. After examining the eyes, I next laid
open, in all its length, from the neck to the point of the sack, the
dorsal bone of the creature--its internal shell, I should rather say,
for bone it has none. The form of the shell in this species is that of a
feather, equally developed in the web on both sides. It gives rigidity
to the body, and furnishes the muscles with a fulcrum; and we find it
composed, like all other _shells_, of a mixture of animal matter and
carbonate of lime. Such was the lesson taught me in a single walk; and I
have recorded it at some length. The subject of it, the loligo, has been
described by some of our more distinguished naturalists, such as Kirby
in his Bridgewater Treatise, as "one of the most wonderful works of the
Creator;" and the reader will perhaps remember how fraught with
importance to natural science an incident similar to the one related
proved in the life of the youthful Cuvier. It was when passing his
twenty-second year on the sea-coast, near Fiquainville, that this
greatest of modern naturalists was led, by finding a cuttle-fish
stranded on the beach, which he afterwards dissected, to study the
anatomy and character of the mollusca. To me, however, the lesson
served merely to vivify the dead deposits of the Oolitic system, as
represented by the Lias of Cromarty and Ross. The middle and later ages
of the great secondary division were peculiarly ages of the
cephalopodous molluscs: their belemnites, ammonites, nautili, baculites,
hamites, turrilites, and scaphites, belonged to the great natural
class--singularly rich in its extinct orders and genera, though
comparatively poor in its existing ones--which we find represented by
the cuttle-fish; and when engaged in disinterring the remains of the
earlier-born members of the family--ammonites, belemnites, and
nautili--from amid the shales of Eathie or the mud-stones of Shandwick,
the incident of the loligo has enabled me to conceive of them, not as
mere dead remains, but as the living inhabitants of primaeval seas,
stirred by the diurnal tides, and lighted up by the sun.
When pursuing my researches amid the deposits of the Lias, I was
conducted to an interesting discovery. There are two great systems of
hills in the north of Scotland--an older and a newer--that bisect each
other like the furrows of a field that had first been ploughed across
and then diagonally. The diagonal furrows, as the last drawn, are still
very entire. The great Caledonian Valley, open from sea to sea, is the
most remarkable of these; but the parallel valleys of the Nairn, of the
Findhorn, and of the Spey, are all well-defined furrows; nor are the
mountain ridges which separate them less definitely ranged in continuous
lines. The ridges and furrows of the earlier ploughing are, on the
contrary, as might be anticipated, broken and interrupted: the effacing
plough has passed over them: and yet there are certain localities in
which we find the fragments of this earlier system sufficiently entire
to form one of the main features of the landscape. In passing through
the upper reaches of the Moray Firth, and along the Caledonian Valley,
the cross furrows may be seen branching off to the west, and existing as
the valleys of Loch Fleet, of the Dornoch Firth, of the Firth of
Cromarty, of the Bay of Munlochy, of the Firth of Beauty, and, as we
enter the Highlands proper, as Glen Urquhart, Glen Morrison, Glen Garry,
Loch Arkaig, and Loch Eil. The diagonal system--represented by the great
valley itself, and known as the system of Ben Nevis and the Ord of
Caithness in our own country, and, according to De Beaumont, as that of
Mount Pilate and Cote d'Or on the Continent--was upheaved after the
close of the Oolitic ages. It was not until at least the period of the
Weald that its "hills had been formed and its mountains brought forth;"
and in the line of the Moray Firth the Lias and Oolite lie uptilted, at
steep angles, against the sides of its long ranges of precipice. It is
not so easy determining the age of the older system. No formation occurs
in the north of Scotland between the Lias and the Old Red Sandstone: the
vast Carboniferous, Permian, and Triassic deposits are represented by a
wide gap; and all that can be said regarding the older hills is, that
they disturbed and bore up with them the Old Red Sandstone; but that as
there lay at their bases, at the time of their upheaval, no more modern
rock to be disturbed, it seems impossible definitely to fix their era.
Neither does there appear among their estuaries or valleys any trace of
the Oolitic deposits. Existing, in all probability, during even the
times of the Lias, as the sub-aerial framework of Oolitic Scotland--as
the framework on which the Oolitic vegetables grew--no deposit of the
system could of course have taken place over them. I had not yet,
however, formed any very definite idea regarding the two systems, or
ascertained that they belonged apparently to a different time; and
finding the Lias upheaved against the steeper sides of the Moray
Firth--one of the huge furrows of the more modern system--I repeatedly
sought to find it uptilted also against the shores of the Cromarty
Firth--one of the furrows of the greatly more ancient one. I had,
however, prosecuted the search in a somewhat desultory manner; and as in
the autumn of 1830 a pause of a few days took place in my professional
labours between the completing of one piece of work and the
commencement of another, I resolved on devoting the time to a thorough
survey of the Cromarty Firth, in the hope of detecting the Lias. I began
my search at the granitic gneiss of the Hill, and, proceeding westwards,
passed in succession, in the ascending order, over the uptilted beds of
the lower Old Red Sandstone, from the Great Conglomerate base of the
system, till I reached the middle member of the deposit, which consists,
in this locality, of alternate beds of limestone, sandstone, and
stratified clay, and which we find represented in Caithness by the
extensively developed flag-stones. And then, the rock disappearing, I
passed over a pebbly beach mottled with boulders; and in a little bay
not half a mile distant from the town, I again found the rock laid bare.
I had long before observed that the rock rose to the surface in this
little bay; I had even employed, when a boy, pieces of its stratified
clay as slate-pencil; but I had yet failed minutely to examine it. I was
now, however, struck by its resemblance, in all save colour, to the
Lias. The strata lay at a low angle: they were composed of an
argillaceous shale, and abounded in limestone nodules; and, save that
both shale and nodules bore, instead of the deep Liassic grey, an
olivaceous tint, I might have almost supposed I had fallen on a
continuation of some of the Eathie beds. I laid open a nodule with a
blow of the hammer, and my heart leaped up when I saw that it enclosed
an organism. A dark, ill-defined, bituminous mass occupied the centre;
but I could distinguish what seemed to be spines and small ichthyic
bones projecting from its edges; and when I subjected them to the
scrutiny of the glass, unlike those mere chance resemblances which
sometimes deceive for a moment the eye, the more distinct and
unequivocal did their forms become. I laid open a second nodule. It
contained a group of glittering rhomboidal scales, with a few cerebral
plates, and a jaw bristling with teeth. A third nodule also supplied its
organism, in a well-defined ichthyolite, covered with minute,
finely-striated scales, and furnished with a sharp spine in the
anterior edge of every fin. I eagerly wrought on, and disinterred, in
the course of a single tide, specimens enough to cover a museum table;
and it was with intense delight that, as the ripple of the advancing
tide was rising against the pebbles, and covering up the ichthyolitic
beds, I carried them to the higher slopes of the beach, and, seated on a
boulder, began carefully to examine them in detail with a common
botanist's microscope. But not a plate, spine, or scale, could I detect
among their organisms, identical with the ichthyic remains of the Lias.
I had got amid the remains of an entirely different and incalculably
more ancient creation. My new-found organisms represented, not the
first, but merely the second age of vertebrate existence on our planet;
but as the remains of the earlier age exist as the mere detached teeth
and spines of placoids, which, though they give full evidence of the
_existence_ of the fishes to which they belong, throw scarce any light
on their structure, it is from the ganoids of this second age that the
palaeontologist can with certainty know under what peculiarities of form,
and associated with what varieties of mechanism, vertebral life existed
in the earlier ages of the world. In my new-found deposit--to which I
soon added, however, within the limits of the parish, some six or eight
deposits more, all charged with the same ichthyic remains--I found I had
work enough before me for the patient study of years.