Town Geology

f your feet-whole streets, or set up as bournestones at corners, or laid in heaps to be broken up for road-metal, certain round pebbles, u

hampton (at least) on the west, you will still find these pebbles, but fewer and smaller as you go south. It matters not what the r

entirely of rolled chalk flints, and bits of beds immediately above or below the chalk. The blocks of "Sarsden" sandstone-those of which Stonehenge is

sweet earth, as they do in the gorge of the Tay about Dunkeld, and all the way up Strathmore, where they form long grassy mounds-tomauns as they call them in some parts of Scotland-askers as they call them in Ireland. These mounds, with their sweet fresh turf rising out of heather and bog, were tenanted-so Scottish children used to believe-by fairies. He that

or along Leith shore, near Edinburgh; or, to give one more instance out of hundreds, along the coast at Scarborough. If you walk along the shore southward of that town, you will see, in the gullies of the cliff, great beds of sticky clay, stuffed full of bits of every rock between the Lake mount

bles have come from the highlands? And if the pebbles are rounded, while the rocks like them in the highlands always break off in angular shapes, is it not,

rely glad to hear it. It was not so very long ago that such arguments wo

ulder clay pebbles from the neighbourhood of Liverpool and Birk

l igneous rocks, that is, either formed by, or altered by volcan

ones of the Lake mountains de

ne, 1 p

s limestone,

es, i.e. rocks immediately r

u are no mineralogist, common sense will tell you, that if they were all concreted out of the same clay, it is most likely that they would be all of the same kind, and not of a dozen or more different kinds. Common sense will tell you, also, that if they were all concreted out of the same clay, it is a most extraordinary coincidence, indeed one too strange to be believed, if any less strange explanation can be found

ee sets of scratches crossing each other; marked, as a cat marks an elder stem when she sharpens her claws upon it; and that these scratches have not been made by the quarrymen's tools, but are old marks which exist-as you may easily prove for yourse

er how they wore rounded and scratched. We must find a theory which will answer our question; and one which, as Professo

, brought

water would be needed to carry boulders, some of them weighing many tons, for many miles. Now Scripture says nothing of any such violent currents; and we have no right to p

certainly would explain their being rounded; though not their bein

becomes still. Now currents of such tremendous violence as to carry these boulder stones onward, would have carried the mud for many miles farther still; and we should find the boulders, no

them as well as over them? On that theory also we should find them only at the bottom of the clay. As it is, we find them scattered anywhere and eve

mud. If you try for seven years, I believe, you will never contrive to make your

on't think you will do, that stones, clay, and all were blown hither along the surface of the ground, by primeval hurricanes, ten times wor

a force which is at work over the vast sheets of land at both the north and south poles; at work, too, on every high mountain

stones g

e scratched

ere imbedd

n the brick-pits,-Would not our common sense have a right to try that explanation?-to suspect that this force, which we do not see at work in Britain now, may have been at work here ages since? That would at least be rea

snows, stretching over the higher land, and crawling downward

sisting of the boulders and gravel, and earth, which the glaci

and in like wise grind, scratch, and polish the rock over whic

m, carrying the finest mud, the result of the grindin

ieures-long lines of stones and dirt which had fallen from neighb

the ice-cliff at its end, to mingle with those thrown out from underneath the glacier, and form huge banks of bou

, so that an ice-cliff one hundred feet high may project into water eight hundred feet deep. At last, when it gets out of its depth, the buoyancy of the water breaks it off in icebergs, which float away, at the mercy of tides and currents, often

ice are imbedded. And this ooze-so those who have examined it assert-cannot be distinguished from the brick-clay, or fossiliferous boulder-clay, so common in the North. A very illustrious Scandinavian

grandeur. Indeed, it would have been an impertinence to have done otherwise; for I have never seen a live glacier, by land or sea, though I have seen many a dead one. And the public has had t

are like, let us imagine what a dead glacier would be like; a glacier, that

mains of the mud from under the glacier, stuck full of stones and boulders iceberg-dropped. This mud would be often very irregularly bedded; for it would have been disturbed by the ploughing of the icebergs, and mixed here and there with dirt which had fallen from them. Moreover, as the sea became shallower and the mud-beds got awash one after the other, they would be torn about, re-sifted, and re-shaped by currents and by tides, and mixed with shore-sand ground out of shingle-beach, thus making confusion worse confounded. A few shells, of an Arctic or northern typ

h, and Irish lowlands must have looked before returning vegetation co

ith these boulder pebbles. No agent known on earth can have stuck t

m as they are scratched, save ice, wh

st beds of boulders which lie along the course of certain northern rivers; notably along the

no doubt, an open question whether some of them may not be the work of water. But nothing but the action of ice can have produced what I have seen in land-locked and quiet fords in Kerry-ice-flutings in polished rocks below high-water mark, so large that I could lie down in one of them. Nothing but the action of ice could produce what may be seen in any of our mountains-whole sheets of rock ground down into rounded flats, irrespective of the lie of the beds, not in valleys, but on the brows and summits of mountains, often ending abruptly at the edge of some s

the Continent. No water power could have lifted those stones, and tossed them up high and dry on mountain ridges and promontories, upon rocks of a totally diffe

ne is sometim

e bald top of

ll who do t

could thither c

ms a thing end

t crawled forth

reposeth, ther

st which has crawled forth, but an ice-beast which has been left behind; lifted up thither by the ice, as surely as the famous Pierre-à-bot, forty feet in diameter, and hundreds of boulders mo

enland is now, and partly, perhaps, by an icy sea. But, to make assurance more sure, let us look for new facts, and try whether ou

to have symptom d also. If I find that, my guess will be yet more probable. He ought also to have symptom e, and so forth; and as I find succ

find sea-shells in their sands and clays? Not abundantly, of course. We can understand that the sea-animals would be too rapidly covere

f, yet in sand-beds mixed with them, and probably underlying them. And this is a notable fact, that the more species of shells they find, the more they wil

d can be pointed out in the strata, though not of course in time, at which these seas began to grow colder, and southern and Mediterranean shells to disappear, their places being taken by shells of a temperate, and at last of an Arctic climate; which last have since retreated either toward their native North, or into cold water at great depths. From Essex across to W

nt sea-beach, five-and-thirty feet thick, lying on great ice-scratched boulders, which again lie on the mountain slates. It was discovered by the late Mr. Trimmer, now, alas! lost to Geology. Out of that beach fifty-seven

t height at which such shells may be found hereafter. For, according to Professor Ramsay, drift

in a "Deus quidam deceptor," in a God who puts shells upon mountain-sides only to befool honest human beings, and gives men intellects which are worthless for even the simplest work. Those shells must mean that that mountain, and therefore the mountains round it, must have been once fourteen hundred feet at l

he beach, and the boulders, and all Snowdonia, fourteen hundred feet into the air. And if anyone should object that the last upheaval may have been effected suddenly by a few tremendous earthquakes, we must answer-We have no proof of it. Earthquakes upheave lands now only by slight and intermittent upward pulses; nay, some lands we know to rise without any eart

imaginations. Have you not played with us, as well as argued with us, till you have inveigled us step by step into a conclusion which we cannot and will not

teaching natural science. We do not want haste, enthusiasm, gobe-moucherie, as the French call it, which is agape to snap up any new and vast fancy, just because it is new and vast. We want our readers to be slow, suspicious, conservative, ready to "gib," as we say of a horse, and refuse the collar up a steep place, saying-I must sto

slowly, but once and for all; and I shall

ce of this past age of ice, or glacial epoch, has been discovered, through many mistakes, many corrections,

face earnestly enough for more than twenty years, and that I am about as certain that they can o

ad not the facts to prove it. But of the facts there can be no doubt. There can be no doubt that the climate of this northern hemisphere has changed enormously more than once. There can be no doubt that the distribution o

rtain strata of rock, older than the ice, have not been destroyed by the grinding of the ice-cap; and they are full of fossil plants. But of what kind of pla

ates. But if we say the latter, we must allow a change in the shape of the land which is enormous. For nothing now can float northward from the United States into Baffin's Bay. The polar current sets out of Baffin's Bay sou

e proved to have gone on in Greenland. It has become c

England was, before the age of ice, much warmer than it is now, and grew gradually

roof is th

d feet of clay. But not ice-clay. Anything but that, as you will see. It belongs to a f

of fossils do

eous plants too-of an Australian type. Surely your common sense would hint to you, that this London clay must be mud laid down off the mouth of a tropical river. But your common sense would be all but certain of that, when you found, as you would find, the teeth and bones of crocodiles and turtles, who come to land, remember, to lay their eggs; the bones, too, of

aid down over your plains? Nay, have we not proved more? Have we not found that that old sea was an icy sea? Have we not wandered on, step by step, into a whole true fairyland of wonders? to a time when all England, Scotland, and Ireland were as Greenland is now? when mud streams have rushed down from under

t is always in science. We know not what we shall discover. But this, at least, we know, that it will be far more wonderful than we had drea

ill at work, and on which, ere young folk are old, they will have discovered, I expect, some startling facts. On that last question, I, being no astronomer, cannot speak. But I should have liked to have said somewhat on matters on which I have knowledge enough, at least, to teach you how much there is to be learnt. I should have liked to tell the student of sea-animals-how the ice-age helps to explain, and is again explained by, the remarkable discoveries which Dr. Carpenter and Mr. Wyville Thompson have just made, in the deep-sea dredgings in the North Atlantic. I should have liked to tell the botanist somewhat of the pro-glacial flora-the plants which lived here before the ice, and lasted, some of them at least, through all those ages of fearful cold, and linger still on the summits of Snowdon, and the highest peaks of Cumberland and Scotland. I should have liked to have told the lovers of zoology about the animals which lived before the ice-of the mammoth, or woolly elephant; the woolly rhinoceros, the cave lion and

ught you, I hope, a key by which to decipher their hieroglyphics. At least, I have, I trust, tau