Earth\s diamonds, or coal, its formation and value

Preface

^/TAN1T who read the following pages will be surprised J-JL to find that the coal production of this country has attained to such enormous proportions as indicated ; and by the figures and facts supplied will understand to some extent our indebtedness as a nation to God for the treasures we possess in our seams of coal.

I am pleased to know that my former efforts to awaken an interest in the minds of others on behalf of our miners have not been altogether in vain; and I sincerely hope that the information given at this time respecting the dangers by which they are surrounded while following their employment may secure them a large measure of consideration and sympathy.

The attention of colliery proprietors, mining engineers, and managers is especially invited to the chapters on "Coal- Dust an Element of Danger in Coal-Mines," and "The Dangers connected with the Use of Gunpowder and other Explosives in Fiery Mines." It is hoped that the subjects dealt with will receive that consideration which their importance justly demands.

PREFACE.

Full credit is given for whatever improvements have taken place under Government regulation, careful management, and improved machinery; while certain things are shown to be necessary even now for giving security to the lives and limbs of the workers in coal-mines.

Having in past years seen some of the sad results of strikes and lock-outs, it affords me pleasure to bear testimony to a better understanding which prevails in all colliery-districts between the employers and the employed.

As false impressions exist respecting the social and moral condition of our colliery- districts, I ask that careful attention may be given to the facts relating to the provident habits of the miners, and the love shown by them to their wives, children, and parents. In the following pages illustrations will be found, not only of filial affection, but of the most devoted yet unassuming piety.

Chapter I. Page

Introduction, . Hi

The study of God's works calculated to nil the mind with wonder and admiration — Table of sedimentary and fossiliferous strata of Great Britain — A regular order observed in the deposition of sedimentary rocks — No discrepancies to be found between Biblical statements and scientific discoveries.

OHAPTEE II.

The distinguishing characteristics of the carboniferous system — The vegetable origin of coal — The beautiful foliage found in some coal measures — Some of the principal plants of the coal-formation — The imagined vegetation of the coal-formation period restored — Chemical processes at work in the formation of coal — The immense period required for such, changes to be accomplished — The "peat bog " and " drift " theories — Bottled light — Meaning of the Biblical account of the Creation.

CHAPTER III. Interesting Facts Connected with the History of Coal- Mining, . . 40

Coal known to our Saxon ancestors — The probability of its having been known to the ancient Britons — Prejudice against its beingused for household purposes — Royal proclamations prohibiting its use in London — Monks leasing a colliery in 1330 — Tax on coal for

CONTENTS.

PAGE

rebuilding St. Paul's and fifty-two parish churches in London — Quantity of coal carried by railways and boats during the year 1880 — The enormous increase of our coal-trade — Some interesting calculations respecting the latent power of coal — Beautiful colours and scents produced by distillation of coal — The decline of the iron trade in wood-land, and its development in coal- districts — The earliest attempts at making iron with coal — The great waste of coal both for household and manufacturing purposes — The immense value of coal to Great Britain.

Chapter IV

Colliers not much thought about by the public generally — A list of the greatest catastrophes in collieries between 1852 and 1882 — Some of the results of explosions — The burdens under which miners laboured in years past — Benefits conferred by Lord Ashley's Act of 1842 — Many of the reports in newspapers and magazines respecting the social and moral condition of colliery -districts not worthy of credit — Miners as a class are simple minded, but strong in their affections — Some striking illustrations of filial affection — Services at Seaham before and after the explosion.

Chapter V

A few words about shaft-sinking, its difficulties and expense — The greatest achievement of this kind — Limits to deep mining — Driving gate roads, or cutting levels — Opening the works— Different systems of working coal-mines — The testimony of the Commissioners — Some pleasing reminiscences — Coal-mining laborious — Deficiency of light — An illustration of the attitude of a coal-miner while at work — The atmosphere which surrounds him — The " black spit" and 11 black lung" of the collier — Circumstances leading to a change of opinion,

CHAPTER VI. Coal-Dust an Element op Danger in Coal-Mines, . . . . 88

The dangers attending accumulations of coal-dust only recently discovered — M. Vital and Mr. Galloway have made most important discoveries — When dust becomes inflammable and explosive —

CONTENTS.

PAGE

Professor Abel's experiments with dust from Seaham and other collieries — The conclusions arrived at of great importance to all persons connected with coal-mines.

Chapter VII

Great improvements of late years — The management of a colliery a work of extreme delicacy and intricacy — Tabulated summaries of catastrophes in mines — The benefits of Government regulation and inspection — The results of superior management — Accidents in shafts — A narrow escape — Falls of roof and coal very destructive of life— Explosions of fire-damp — Difficulties in the way of sending the exact quantity of air through an extensive mine to ensure its safety — The point at which carburetted hydrogen gas becomes explosive — Safety-lamps described — How far they are to be trusted —Outbursts of pent-up gas— An ingenious invention for increasing the safety of the lamp.

Chapter VIII

The Dangers Connected with the use of Gunpowder and other Explosives in Fiery Mines, 123

The Commissioners report a difference of opinion entertained by witnesses respecting the use of gunpowder in fiery mines — Some of the inspectors strongly opposed to its use — Explosions traced to it in many instances — A drill which may possibly render explosives less necessary — The 8th clause in " The Coal-Mines Regulation Act " of 1872 — The opinion of the Law Officers as to its meaning — This ruling approved by the representatives of 250,000 colliers — The electric-light, and experiments with it in coal-mines — Papers relating to it read at the British Association Meeting, September, 1881.

CHAPTER IX. Dangers to which Colliers are Exposed (continued), . . 140

Explosions very much alike in their results — The explosion at Abercarne, September, 1878 — A marvellous escape at Penygraig — A few suggestions for preventing such catastrophes — A remarkable

CONTENTS.

PAGS

escape after " holing " into old working-places — A pit's company imprisoned nearly six days — Joe's conduct worthy of imitation— The perilous position of the men in Tymerwydd mine for ten days — Much of the time spent in singing and prayer — Thanksgiving services held in the neighbourhood after their rescue — Hartley calamity the worst on record among accidents of a miscellaneous character — How it happened — An overwhelming sight— Pleasing discoveries respecting the character and conduct of the poor men — A letter written by one of the volunteers who explored the Oaks Colliery.

CHAPTER X. A Permanent Relief Fund Required in all Colliery-Districts, 167

My own thoughts on the subject — " The Northumberland and Durham Miners' Permanent Relief Fund" a move in the right direction — Objects of the Society — Contributions and benefits — Employers supplement the contributions of their men — Similar societies formed in six other districts — Observations of the Newcastle Chronicle respecting the value of such societies — "The Central Association for dealing with Distress caused by Mining Accidents" — Other societies in which colliers are interested — Testimony to their value by Mr. T. Burt, M.P., and others interested in the good understanding of employers and employed.

CHAPTER XT.

Many Christians, and a goodly number of preachers and Sunday-school teachers to be found in coal-mines — Daily reading of the Bible and prayer in coal-mines — A short account of the life of William — His conversion — His estimate of the value of prayer — Selections from his correspondence — His anxiety for the spiritual welfare of others.

Chapter XII

William's impression that his time on earth was drawing to a close — His illness — Recovery, and return to his employment — His last letter.

CONTENT?.

Chapter XIII. Page

William goes to his work for the last time — Words spoken when about to descend the shaft — Sings while descending — His conduct during the forenoon — Thinks "about solemn things" — His conduct during the dinner hour and prayer meeting — Is heard singing during the afternoon — A message to a dearly-loved friend, if1 he should not see her again — A desire expressed after the week's labour was ended that all in the mine should unite in singing a hymn — Left at the bottom of the shaft by his friend — William afterwards commenced to ascend — Knocked out of the "skip" by a falling brick, and drowned in " the sump " at the bottom of the shaft — Reflection's — A fine field for Christian enterprise to be found in colliery-districts.

EARTH'S DIAMONDS.

Introduction

THERE is one verse in the Bible which, though standing in immediate connection with the doctrine of Divine Providence, is more or less applicable to all God's works. It is the following : " The works of the Lord are great, sought out of all them that take pleasure therein." We have here a golden link between science and revelation. It sounds like a voice from the realms of universal nature, bidding us to search into the laws which govern them, take pleasure in the phenomena which they present to us, and try to measure the power of their Creator by the magnitude of the forces which regulate them.

Although the universe of visible things has no faculty of speech, no articulate language, it is constantly declaring the glory of God, and conveying instruction to every age and country, and enlarging our ideas respecting the magnitude of His works.

earth's diamonds.

Notwithstanding the fact that only a few years have passed since anything approaching certainty was attained respecting the history of the earth, as recorded in its manifold and varied strata, it must be admitted that we know quite enough at the present time to excite wonder and

admiration.

Previous to entering upon a consideration of the nature and origin of coal, it appears desirable that a few facts should be given respecting the crust of the earth in general, and the position occupied in it by the coal-formations of our own country more particularly.

TABLE OF SEDIMENTARY AND FOSSILIFEROTJS STRATA OF GREAT BRITAIN

(showing the order of their succession).

POST TERTIARY, OR QUATERNARY.

RECENT AND PREHISTORIC.

Alluvium ; river deltas ; some cave earths and raised beaches, and generally the deposits now forming in rivers and seas, in which shells and other fossils are all, with rare exceptions, of existing species.

PLEISTOCENE, OR POST-PLIOCENE.

Cave deposits generally ; older river gravels and raised beaches, with shells and other fossils of extinct or locally extinct species. Bridlington beds.

INTRODUCTION.

TERTIARY, OR CAINOZOIO.

PLIOCENE.

Chillesford and Aldeby beds; Norwich crag; red crag of Suffolk ; white, or coralline crag of Suffolk.

MIOCENE.

Upper. — Wanting.

Lower. — Lignite beds of Bovey . Tracey ; leaf bed of Mull; lignite of Antrim; Hempstead beds (Isle of Wight).

EOCENE.

Upper. — Bembridge marls and limestone ; Osborne beds ; Headon beds (fresh-water and estuarine).

Middle.— Barton clay ; Bracklesham beds ; Upper and Lower Bagshot sands and clays, with plants.

Lower. — London clay (including the Bognor beds); Blackheath and Oldhaven beds; Woolwich and Reading beds; Thanet sands.

SECONDARY, OR MESOZOIO.

CRETACEOUS.

Upper. — White chalk with flints; lower white chalk without flints ; chalk marl.

Middle. — Upper green sand (Godstone firestone, &c.) ;

gault.

Lower. — Lower green sand (or neocomian), including Folkestone beds, Sandgate beds, Hythe beds, Atherfield clay, Wealden clay (fresh- water), Hastings beds.

earth's diamonds.

OOLITE.

Upper. — Purb'eck beds (upper, middle, and lower — fresh-water and estuarine) ; Portland stone and sand ; Kimmeridge clay.

Middle.— Upper calcareous grit; coral rag, or coralline oolite; lower calcareous grit ; Oxford clay; Kelloway rock.

Loiver. — Cornbrash ; great oolite (including forest marble and Bradford clay, Bath oolite, Stonesfield slate, Fuller's earth oolite, Moorland coal-beds of Yorkshire, and the Brora coal-beds of Scotland) ; inferior oolite or liassic sands.

LIAS.

Upper. — Clays.

Middle. — Marlstones.

Lower. — Clays and limestones.

RH03TIC OR PENARTH BEDS.

(White lias, black shales, and grey marls).

TRIAS OR NEW RED SANDSTONE.

Upper. — Keuper beds ; red shales of Cheshire and Lancashire, with rock salt; dolomitic conglomerates of Somersetshire.

Middle. — Wanting.

Lower. — Bunter or new red sandstone of Lancashire and Cheshire.

PRIMARY OR PALAEOZOIC.

PERMIAN.

Upper Permian, or magnesian limestone series. Lower Permian, consisting of red sandstone, marl, breccia and conglomerates, &c.

INTRODUCTION.

CARBONIFEROUS.

Upper. — Coal-measures of England and Wales; millstone grit; Yoredale series of Yorkshire.

Lower. — Carboniferous limestone (or mountain limestone) ; lower limestone shales.

DEVONIAN — MARINE. V

Upper. — Marwood and Petherwin beds. ( Old Red Middle. —Plymouth, Ogwell, Ilfracombe, / Sandstone— and Combe Martin beds. \ Lacustrine.

Lower. — Linton and Fowey beds. /

SILURIAN.

Upper Silurian. — Upper Ludlow beds ; Lower Ludlow beds ; Upper Wenlock limestone and shales ; Lower Wenlock and Woolhope beds, and Denbighshire grits ; Trannon shales; Upper Llandovery rocks (May Hill sandstone).

Lower Silurian. — Lower Llandovery rocks ; Bala and Caradoc beds ; Upper Llandeilo beds ; L6wer Llandeilo (or Arenig) beds ; Tremadoc slates ; Lingula (or Lingulella) flags ; Menevian beds.

CAMBRIAN.

PRE-CAMBRIAN.

Gneissic rocks of Capes Wrath and Lewis ; " Dimetian," " Pebidian," and " Arvonian" rocks of Wales, granite, &c, unstratified.

No man, who has carefully studied the subject, can

entertain a doubt respecting the enormous epochs which

B earth's diamonds.

must have been necessary to produce the different systems and varied, strata . of the earth, as indicated above. On examination, it will, be seen that there is a regular order observed in the deposition of sedimentary rocks, each of the divisions being marked' by distinct organic remains, representing many successive races of plants and animals, which have been buried beneath the aqueous changes of our globe ; during which changes thousands of species and genera have become extinct, so that the flora and fauna now living are but a small part of those which once lived in the past.

Who can take into review the vast superpositions of different strata on the same spot, indicating successive alternations of fresh- water deposits and deep-sea bottoms, subsidences and elevations, dislocations and denudations, Arctic climates and tropical, with buried remains of the most divergent forms of flora and fauna, and not be convinced that all this must of necessity represent the gradual accretion of successive ages ?

As we proceed, we shall see that there are no discrepancies between the statements contained in the Bible respecting creation, and the discoveries of scientific men.

Section of the Terrestrial Crust, Sbcwmg the ^JfferentToxaiLations From the MOST RECENT TO THE MOST ANCIENT

F ormatitm Cizcrespa8m§ System.

Alluvial m

Puviat - ■ ^/0^^M^iWW?M )

Cretaceous .

Jurassic.

Tciassic :

Permian

Coallfeasures

Bevoraali.-.

SECONDARY

Silurian.

yyyy^yyy>yy.y<. ■:>

yy > yy^y/ //yy, y7/s

PRIMARY

Carabrkii

— Ml

Chapter II. Coal— Its Formation* And Value

rilHE carboniferous system is distinguished by the vast ■A- amount of carbon, in the form of coal, accumulated in its layers.

The condition of things, in regard to the vegetation whence coal was derived, was similar to the present. The sunshine and rain, "Winter and Summer, river and lake, have all written their annals in the coal-beds. There must, however, have been a different distribution of land and water, and terrestrial temperature, for we find traces of sub-tropical vegetation in the coal-shales of the Arctic regions.

Although coal had been formed both before and after the carboniferous and oolitic epochs, it must not be overlooked that its principal development is found to have taken place in those ages. Looking at the enormous development at this epoch, of forest and swamp, composed of nearly identical vegetation in all parts of the world, we have only to remark that there has been nothing like it since; and that all subsequent formations have shown wider and wider divergences from the carboniferous type.

That our seams of coal are the remains of forests, bogs,, and moors, is evidenced by the huge trees of strange forms> earth's diamonds.

thick hedges of tall reeds, and plants, and leaves, which are discovered in the different measures ; and also by their microscopic structure, combustible properties, chemical composition, and certain phenomena which may generally be observed in reference to the position occupied in the strata.

The vegetable origin of coal was recognised as far back as 1785, by the philosopher Hutton. It was left, however, for others to discover that there were hundreds of species of plants in our coal-measures and carboniferous rocks. By the researches of Professor Goppert the number has been increased to 879.

In a description of the beautiful foliage which is to be seen in the coal-measures of Bohemia, Dr. Buckland says : —

" The most elaborate imitations of living foliage upon the painted ceilings of Italian palaces, bear no comparison with the beauteous profusion of extinct vegetable forms with which the galleries of these instructive coal-mines are overhung. The roof is covered as with a canopy of gorgeous tapestry, encircled with festoons of most graceful foliage, flung in wild, irregular profusion over every portion of its surface. The effect is heightened by the contrast of the coal-black colour of these vegetables with the light ground-work of the rock to which they are attached. The spectator feels himself transported, as if by enchantment, into the forests of another world. He beholds trees, of forms and characters now unknown upon the earth, presented to his senses almost in the beauty and vigour of their primeval life ; their scaly stems and bending branches, with their delicate apparatus of foliage, are all spread forth before him, little impaired by the lapse of countless ages, and bearing faithful records of extinct systems of vegetation which began and terminated in times of which these relics are the infallible historians."

COAL — ITS FORMATION AND VALUE.

The researches of Goppert, MacCulloch, Sir James Hall, Sir W. Logan, Dr. Dawson, and others, have resulted in leading students generally to conclude that the beds of fireclay, which underlie all seams of coal, represent the original land surfaces upon which the coal-forming vegetation grew; that the stigmaria found in the uncler-clays were the roots of that vegetation, which implies that the plants were of the lepidendroid order; that the vegetation grew near the mouths of great rivers in swampy ground, and there underwent submergence ; changes then took place which converted the vegetable matter into coal ; that the change of coal from one variety to another, even in the same seam, is the result of metamorphism, and is indirectly caused by the contortion of the surrounding strata, whereby facilities for the escape of gases evolved by the vegetable decomposition have been produced.

Exceptions have been taken to the above conclusions by a few persons* they are not, however, of sufficient weight and importance to set aside the deliberate judgment of a large number of the most eminent men in the scientific world.

The imagined vegetation from which coal was formed was

thus restored by the late Hugh Miller, in "The Old Red

Sandstone." We have brought before our notice a low

shore thickly covered with vegetation —

"Huge trees of wonderful form stand out far into the water. There seems no intervening beach. A thick hedge of reeds, tall as the masts of pinnaces, runs along the deeper bays like water-flags at the edge of a lake. A river of vast volume comes rolling from the interior, darkening the water for leagues with its slime and mud, and bearing with it to the open sea, reecls, and fern, and cones of the earth's diamonds.

pine, arid immense floats of leaves, and now and then some bulky tree, undermined and uprooted by the current.. We near the coast, and now enter , the opening of trie stream. A scarce penetrable phalanx of reeds, that attain to the height and well-nigh the bulk of forest trees, is ranged on either hand. The bright and glossy stems ' seem rodded like Gothic columns; the pointed leaves stand out green at every joint, tier above tier, each tier resembling a coronal wreath or an ancient crown, with the rays turned outwards, and we see atop what may be either large spikes or catkins.

" What strange forms of vegetable life appear in the forest behind! Can that be a club-moss that raises its slender height for more than fifty feet from the soil? Or can these tall, palm-like trees be actually ferns, and these spreading branches mere fronds ? And then these gigantic reeds ! are they not mere varieties of the common horsetail of our bogs and morasses, magnified some sixty or a hundred times? Have we arrived at some such country as the continent visited by Gulliver, in which he found thickets of weeds and grass tall as woods of twenty years' growth, and lost himself amid a forest of corn fifty feet in height ? The lesser vegetation of our own country, its reeds, mosses, and ferns, seem here as if viewed through a microscope ; the dwarfs have sprung up into giants, and yet there appears to be no proportional increase in size among what are unequivocally its trees. Yonder is a group of what seem to be pines, tall and bulky it is true, but neither taller nor bulkier than the pines of Norway and America; and the club-moss behind shoots up its green hairy arms, loaded with what seem catkins, above their topmost cones.

"But what monster of the vegetable world comes floating down the stream, now circling round in the eddies, now dancing on the ripple, now shooting down the rapid ? It resembles a gigantic star-fish, or an immense coach-wheel divested of the rim. There is a green dome-like mass in the centre, that corresponds to the nave of the wheel or the body of the star-fish ; and the boughs shoot out horizontally on every side, like spokes from the nave or rays from the central body, The diameter considerably exceeds forty feet ;

COAL — ITS FORMATION AND VALUE.

the branches, originally of a deep green, are assuming the golden tinge of decay, the cylindrical and hollow leaves stand out thick on every side, like prickles of the wild rose on the red, fleshy, lancelike shoots of a year's growth, that will be covered two seasons hence with flowers and fruit. That strangely formed organism presents no existing type among all the numerous families of the vegetable kingdom.

" There is an amazing luxuriance of growth all around us. Scarce can the current make way through the thickets of aquatic plants that rise thick from the muddy bottom ; and though the sunshine falls bright on the upper boughs of the tangled forest beyond, not a ray penetrates the more than twilight gloom that broods over the marshy platform below. The rank steam of the decaying vegetation forms a thick blue haze that partially obscures the underwood. Deadly lakes of carbonic acid gas have accumulated in the hollows; there is a silence all around, uninterrupted save by the sudden splash of some reptile-fish that has risen to the surface in pursuit of its prey, or when a sudden breeze stirs the hot air and shakes the fronds of the giant ferns, or the catkins of the reeds. The wide continent before us is devoid of animal life, save that its pools and rivers abound in fish and mollusca, and that millions and tens of millions of the infusory tribes swarm in the bogs and marshes. Here and there, too, an insect of strange form flutters among the leaves. It is more than probable that no creature furnished with lungs of the more perfect construction could have breathed the atmosphere of this early period and have lived."

"We have reason for believing that the composition of the trees and plants of the coal-period was of the same kind as that of the present age, the essential constituents being, carbon, hydrogen, oxygen, and nitrogen, with a small quantity of mineral matter, derived from the soil. It appears from the researches and experiments of Professor Liebig, and other eminent chemists, that when wood and earth's diamonds.

vegetable matter are buried in the earth, exposed to moisture, and partially or entirely excluded from the air, they decompose slowly, and evolve carbonic acid gas; thus parting with a portion of their original oxygen. By this means they become gradually converted into lignite or wood coal, which contains a larger portion of hydrogen than wood does, A continuation of decomposition changes the lignite into common or bituminous coal, chiefly by the discharge of marsh gas or carburetted hydrogen.

The main .difference between wood and coal consists in the loss of hydrogen and oxygen by the wood, and the increase of carbon by the coal.

The average constituents of plants and coal may be stated thus : —

Plants. Coal. . Carbon, . . . 46*0 82 '0

100-0 100-0

Here we have an explanation of the change which has taken place during the process of carbonising. The proportion of carbon has almost doubled, and more than threefourths of the oxygen and one-half of the nitrogen have disappeared, leaving the hydrogen free to form hydro-carbon compounds ; while the ash remains the same.

" The copious discharge of carbonic acid and carburetted hydrogen given off by wood in its conversion into coal, appears to have taken place for the most part during the progress of decomposition in the

COAL— ITS FOEMATION AND VALUE.

coal-period ;' for it lias been found by a; comparison of the analyses of true, coal with the lignite of the tertiary strata, that the difference in the percentage of oxygen and hydrogen in these two classes of minerals is not very great. In lignite the oxygen is only 1 *54 per cent., and the hydrogen only 0*38 per cent, more than in true coal.- It would therefore appear that, in the long lapse of time between the carboniferous and tertiary periods, the coal experienced an extremely slight loss of substance. In the coal-fields these gases are constantly escaping in jets from the shallower seams; but in the deeper parts are pent up at an enormous pressure, and by their elastic force materially assist the miner in his excavations."*

It has been estimated that it takes about four tons of vegetable matter to make one ton of coal. Assuming this calculation to be as correct a one as can be made, we find that nearly 550,000,000 tons of vegetable matter would be requisite to produce the quantity of coal procured from the coal-mines of Great Britain during the year 1879, and about 580,000,000 tons would be necessary for the supply of coal in the United Kingdom for 1880.

In reference to the accumulation of the immense bulk of vegetation gathered together in our coal-measures, there have for several years been two leading opinions. Some writers advocate most strenuously the " drift " theory; while others are not less confident in their defence of the " peat-bog " theory.

According to the " peat-bog " theory, forests and jungles grew in the present coal localities, decayed into peat-mosses, suffered subsidence with the land, which thus became the bashr of a lake or estuary, into which broad rivers conveyed

■". * " The Coal-fields of Great Britain," by Professor Hull. 4th ed., p. 77. ;

earth's diamonds.

mud and sand, out of which were gradually consolidated the now overlying and underlying shales and sandstones ; and, during this period the vegetable material became bitumenised and mineralised into coal. The same area was again raised from the waters, was the ground for luxuriant vegetation, was again submerged, and again covered with successive depositions of shale and sandstone. An alternating subsidence and elevation are, in this view, presumed to have taken place for every seam of coal we find ; so that the coal-seams in any of our deposits may be regarded as so many land wastes, and the sandstones and shales as river wastes; and in both of these we now possess a kind of amphibious chronology — a well-marked scale on which we may read off the successive periods of sunshine and flourishing vegetation — of decay and desolation— of disappearance and submergence— of reappearing and returning luxuriance — and of another era of upshooting tree-ferns, outspreading club-mosses, and broad, flag-like foliation.

The " drift' ' theory, however, does not permit us to indulge such visions to the full extent. It admits of partial and limited submersions and elevations of land, such, indeed, as are now taking place on our earth, and also of dense jungles and peat-mosses experiencing the same submersions; but its distinctive features are, that the main bulk of the coal-measures were deposited as drift and silt on lakes and estuaries, that the chief constituent vegetation was imported by rivers and inundations into such estuaries, and that numerous rivers might discharge their several freights of plant remains, or of mud and sand, into one estuary.

FOSSIL TREES FOUND IN COAL-SEAMS.

COAL — ITS FORMATION AND VALUE.

These transporting rivers were themselves exposed to periodical inundations like the Nile and the Ganges ; during the intervals between which the vegetation, rank and rapid, grew and closed up the deltas, and then furnished an important addition to the inland drift, the whole finally travelling down to form coal in the lakes of estuaries. The beautiful foliage in the coal-seams of Bohemia, and the delicate leaves in all their perfection which are to be seen in our geological museums, are considered to be favourable to the " peat-bog " theory ; whereas the immense trees and plants, which in some places are deposited in such a manner as to lead to the conclusion that some mighty influence has been at work, are adduced in favour of the " drift" theory. Whichever theory may be right, we cannot help adoring the wisdom and benevolence of God in storing up the fuel of the world, in such a manner, that it enables us to devote the surface of land to the growth of food for man and fodder for cattle.