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and then some fans of specimens collected by Count Strzelecki, along the w the iscarmens stern chain of Australia. Seeing the great similarity of the narrow seen 2 and Vom a Je rences of the rocks of those two distant countries, I could have le difficulty in drawing a parallel between them; in doing which, I was naturally struck by the circumstance, that no gold had yet been found' in the Australian ridge, which I termed in anticipation the Cordillera.' Impressed with the conviction that gold would, sooner or later, be found in the great British colony, I learned in 1846 that a specimen of the ore had been discovered. I thereupon encouraged the unemployed miners of Cornwall to emigrate and dig for gold, as they dug for tin in the gravel of their own district. These notices were, as far as I know, the first published documents relating to Australian gold." ("Siluria.")

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marse of" be larger vers S tract of po voren of Secand far must than to the arrer area of country is Pan cwaris ne west. All the yes son ji 20 Severn and its Serman Covan. The plains muule and east of England rid, vers; and from the nature insertion of canals has been a

ochromiteto 2f Mineral Products. RealFence of minerals are in veins or 'Puta Age of Tregular beds, and in connection The consideration of the disicials will be treated of under these

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Influence of Igneous Rocks in the Development of Minerals in Veins.

Mineral veins occur in igneous rocks as well as in aqueous rocks; but the intrusion of an igneous mass among stratified deposits appears to have rendered their lodes richer than when conditions otherwise similar obtain.

1. Med to Vint Thousa lithic ult, in the present state of our know- Gold is usually found in a quartz matrix, traversing ceran the laws regulating the deposit of paleozoic shales, chiefly those of the lower Silurian "ilinerom. mactor, you we are able, from general ob- epoch; and the auriferous lodes are frequently richest in vrvata of the geological structure of the earth, to say the vicinity of eruptive rocks. But the precious metal arch may be made for minerals with some is found also in secondary rocks, such as those of Cali , and that there exploration will be futile.fornia, Peru, etc., yet under circumstances exceptional to the usual mode of association of gold. It appears that where certain igneous eruptions, diorite especially, have penetrated the secondary strata, the latter have been rendered auriferous for a limited distance only beyond the junction of the two rocks; and it is concluded that all secondary and tertiary deposits (except the auriferous detritus of the latter), not so specially affected, never contain gold.

Hole d of thounds of pounds have been expended ming up of mineral districts; a large propordem utterly without profit.

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7. at Betain possesses a rich supply of minerals; we dd, alvor, copper, lead, tin, zinc, antimony, nickel, det, bi muth, uranium, chromium, and other of the meal, besides vast stores of iron; our coal beds qeseamous, and earthy minerals are in great variety and valus Statistics show that in Great Britain 350,000 actually engaged in mining operations, exThor of quarries of all kinds, and that the produce is od che, medium annual value of £40,000,000.

es from which we derive our chief supply of mdaki mes almost wholly confined to paleozoic rocks. rence may be sketched as follows:information in North Wales, in the Isle of Abu un Cumberland, in the lead hills of the south of Dodland 16 Jarts of the Highlands, and in parts loud, contains metalliferous veins which yield plastik egr, lead, silver, antimony, arsenic, and

The pocke of the Devonian formation in Devon and eromall Féadain rich tín, copper, and lead lodes. Phonelanderous limestone in Derbyshire, ranging up they walk of England through Cumberland and the Apat berbak, also of the Mendips, and in Devon, pitory of our lead ores. The same formatra Paeonka large and rich deposits of hæmatite, , in the Forest of Dean and Somerset

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theeched the world, all the metalliferous lodes, far exceptions hereafter to be mentioned, For the associated igneous rocks, not 14 Permian. It is thus that one generalisaInquiry is arrived at, viz., that of the period much the lodes carrying our richer metals pus Geology, like the more exact sciences, is Advancing philosophical inductions to very Sir Roderick Murchison was entegige oplossal moules. ulded in 1844, from the study of the gold-bearing tracts His, to predict the discovery of gold in Australia. 1 Sir R. Murchison, "in the year rned from the auriferous Ural Mounvantage of examining the numerous

The lodes carrying copper and tin in Cornwall and Devon are richest about the junction of the killas (local name for the slaty rocks of the Devonian formation in this district), and the bosses of granite, and where they are intersected by granitic dykes, termed elvans. It is worthy of remark that these metalliferous veins have a course or strike nearly east and west, and that these phenomena are not confined to this area, but are exhibited in Saxony and elsewhere.

Other examples might be adduced, but these will suffice to show that intrusive rocks influence the metalliferous richness of veins.

2. Bedded Mineral Deposits.

These include coal and iron ore of primary importance: and salt, gypsum, cement-stones, coprolites, iron-pyrites, bituminous shales, etc., of secondary value.

(a.) Coal occurs in many formations; it has been mined for upwards of a hundred years at Brora, in Sutherlandshire, in rocks of the oolitic epoch, and is worked at Bovey Tracey, Devonshire, in Miocene beds. An anthra cite occurs in the Devonian rocks in Spain; there are good workable coals of the age of the trias in Virginia and Hindostan, and of that of the lias in Hungary; and less valuable coals, chiefly brown coals, occur in tertiary strata in Austria and other parts of Germany. But by far the richest and largest supplies are drawn from the carboniferous system in Great Britain, Belgium, United States, Nova Scotia, Australia, etc.

In Great Britain no coal is found below carboniferous strata, but it does occur in newer strata. In the midland and south-western counties of England, and in South Wales, it is confined to the true coal measures underlain by the millstone grit, locally called the "farewell rock," because, in the language of the miner, when that rock is reached, one bids farewell to the coal. But in the north of England and in Scotland workable coal seams occur

in the inferior formations of the carboniferous system, as well as in the coal measures.

The right understanding of the law of superposition of rocks in relation to our coal-bearing strata, is of value not only to the man of science, but to every speculator in mines, and to every landed proprietor who cares to understand the mineral value of his property. Not long ago considerable funds were spent at Tullygirvan, Co. Down, in a useless search for coal. The adventurer had set to work in black Silurian shales, their mineral aspect resembling that of certain coaly strata, with which he was, perhaps, familiar; but had he possessed even a slight acquaintance with organic remains, he would have abandoned his experiment at the commencement, for the shales were charged with graptolites. Now the scientific miner knows that rocks containing graptolites, trilobites, etc., existed untold ages before the epoch of the coal strata; so that when he meets with those remains, he concludes that money spent in search of coal beneath them will be turned into irredeemable dust, for they occupy, in the irreversible order of deposits, a position thousands of feet beneath the coal measures.

Lord Londonderry bored in the old red sandstone, at Mount Stewart, Co. Down, in search of coal: here, though no fossils occurred, yet the position of the sandstone strata above the previously mentioned Silurian shales, and overlaid as they are by mountain limestone, proved the impossibility of coal being found.

In the neighbourhood of Carrickfergus are two silent witnesses of the folly of sinking for coal where the geological structure of the country precludes the possibility of its presence, or of its occurrence at reasonable depths. Trial shafts had been sunk in new red sandstone, which was pierced to a depth of about 1,000 feet, when the adventures were abandoned. Before coal could be reached, the Permian strata would have to be passed through; and from the unconformability of the new red sandstone to the Permian, and of that set of strata to underlying formations in this district, it was even doubtful if coal could be reached at all.

But coal has been successfully reached by the penetration of newer unconformable strata; thus in the Somersetshire coal field, the coal shafts pass through new red sandstone, the Permian strata being absent. The famous Monkwearmouth pit passes through 330 feet of overlying Permian rocks.

In these and other instances that might be adduced the undertakings had been commenced at the suggestions of those who were perfectly satisfied, from an examination of the surrounding country, of the feasibility of the venture. Yet, on the other hand, attempts have been made to reach coal from below secondary rocks, when, with but a broad knowledge of the geological structure of the country, the trials should have been at the outset abandoned. Thus, at Kingsthorpe, near Northampton, a shaft was sunk through the lower oolite and lias, at an expenditure of nearly £30,000; the adventurers desisted when they reached the new red sandstone. A similar trial took place near Lyme Regis, the lias being bored for coal at an expense of several thousand pounds; the deception was fostered by the accident of passing through a piece of lignite.

(b.) Iron Ores.

Certain ores of iron occur in lodes in primary strata, but others, especially the spathic and brown hæmatite ores, are intercalated as bands among shales and limestones of the carboniferous, liassic, oolitic, wealden, and Cretaceous strata; but by far the largest supply is obtained from the carboniferous system, the one shaft often communicating with both coal and iron-stone workings, and the same group of rocks furnishing limestone.

CORRESPONDENCE IN FRENCH.-V. 17.-FORM OF ADVICE OF A TRAVELLER'S VISIT. Lyons, March 28th, 1864.

Messrs. Smith, Cook & Hyde, London.

Roche will wait upon you to submit to your inspection samples Gentlemen,-We beg to inform you that our Mr. Robert of our latest manufactures in Dresses and Shawls, Waistcoatings, Cravats and Handkerchiefs.

Trusting soon to be favoured with a large order,
We remain, Gentlemen,
Your obedient Servants,

LECOUTEUR, GASPARD & Co.
Lyon, le 28 Mars 1864.

Messieurs Smith, Cook & Hyde, à Londres. Messieurs,-Nous avons l'honneur de vous annoncer que notre M. Robert Roche se présentera chez vous pour vous soumettre les échantillons de toutes nos nouveautés pour robes, chales, étoffes pour gilets, cravates et foulards. Dans l'espoir de recevoir bientôt une bonne commande, Nous vous présentons, Messieurs, nos salutations empressées,

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Gentlemen,-It is now more than three months since we had any orders from your firm; nevertheless, we are persuaded that the fault does not lie with us, or the manner in which we have executed your last.

We are more vexed than you at the rise in velvet, and we know that your sale must in consequence be hampered. If you, however, realise that throughout France and Italy cocoons have fetched from 6 fr. to 6 fr. 90 c. per kilogram that is to say, 18% more than last year, and that consequently silk costs us more than 18% above last year's prices-you will see the necessity of our raising the price of our velvet in proportion.

You will find in our parcel some samples of what we have in stock, and we subjoin our price list.

Our Mr. Marchand will be in Paris next Tuesday, and will have great pleasure in giving you further details.

We are, Gentlemen,

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prix que vont subir nos velours, et nous sentons bien que cela vous gênera pour la vente. Figurez-vous que les cocons se sont payés partout en France et en Italie de 6 fr. à 6 fr. 90 le kilogramme c'est-à-dire, 18% plus cher que l'an dernier-les soieries de toute cette campagne vont donc nous coûter 18% de plus que l'an dernier, et il faut que nous augmentions nos velours en proportion.

Vous trouverez dans notre envoi quelques échantillons de ce que nous avons de disponible en magasin, et ci-joint notre note de prix.

Notre M. Marchand sera à Paris Mardi prochain, et aura le plaisir de vous entretenir plus longuement de tous ces détails. Agréez, Messieurs,

Nos saluts empressés,

JACQUES MARCHAND, BRIGAUD & CIE.

20.-CIRCULAR LETTER OF CREDIT, ETC.

London, March 4th, 1863. Gentlemen,This circular letter of recommendation and credit will be remitted to you by James Muirhead, Esq., of Edinburgh, a gentleman for whom we claim from you a friendly reception, and we beg you to give him an opportunity of entering into business relations with the large landholders of your country. Mr. Muirhead belongs to one of the richest families in Scotland, and himself superintends his extensive and flourishing estates. As he intends looking over the land in the neighbourhood of your metropolis, you will oblige us by paying every * attention in your power to his family, who, having accompanied him thus far, will remain a few weeks in your city during his short absence.

As to the funds which Mr. Muirhead will require, we beg to open a credit with you in his favour for the sum of £5,000 (five thousand pounds sterling), which you will please to pay, indorsing on this letter each of the sums he will have received to the full amount of his credit. Please add to the amount your com. mission and all other expenses, and draw on us for the whole sum at the best possible rate of exchange, and at the date customary in your town.

Assuring you that due honour will always meet the drafts for the payments you will make to James Muirhead, Esq., the receipts for which you will be kind enough to send us, we beg to thank you beforehand for the attentions you will show to this 'gentleman and his family.

We shall always have the greatest pleasure in rendering you similar or other services, and begging you to command the same at any time,

We are, Gentlemen,

Your obedient servants, SPIELMAN & Co.

Messrs. N. N. at Berlin, Vienna, Trieste,

Venice, Rome, Naples.

Messieurs,

Londres, le 4 Mars, 1863.

La présente lettre circulaire de recommandation et de crédit Vous sera remise par James Muirhead, Esq., d'Edimbourg, auquel nous vous prions de vouloir bien faire un accueil obligeant, et lui procurer en même temps la possibilité de se mettre en relation d'affaires avec les grands propriétaires de votre pays. Mr. Muirhead appartient à une des plus riches familles de l'Écosse, dont les terres prospèrent sous sa direction. Vous nous obligerez infiniment, Messieurs, si vous pouvez aussi contribuer aux agréments d'un séjour de quelques semaines que la famille de notre recommandé fera dans votre capitale, tandis que Mr. Muirhead lui-même visitera les terres voisines de la métropole.

Quant aux fonds dont Mr. Muirhead aura besoin, nous l'accréditons chez vous pour une somme totale de £5,000 st. (nous disons cinq mille livres sterling), qu'il vous plaira de lui payer, en marquant sur le dos de cette lettre chacune des sommes qu'il aura touchées jusqu'à épuisement de son crédit. Vous voudrez bien chaque fois ajouter à ces paiements votre commission de banque et tous les autres frais, en vous remboursant sur nous au meilleur cours possible et à l'échéance qui conviendra aux usages de votre place.

En vous assurant, Messieurs, que le meilleur accueil sera tou jours préparé à vos traites pour les paiements que vous ferez à

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Mr.

SPIELMAN & CIE.

21.-LETTER OF INTRODUCTION.

Stuttgard, Jan. 1st, 1840. Gentlemen (Sir),-We beg to introduce to you the bearer, whom we recommend to your kindness. We at the same time open in your account a credit of £1,000, to which amount please furnish Mr. with the sums he requires upon his receipts, which please send us, when debiting our account for your payments. Accept beforehand our best thanks for the services you will render Mr. and believe us to be, Gentlemen (Sir), Faithfully yours,

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months.

J. WEBER & Co.

Valid for Stuttgard, le 1 Janvier, 1840. Messieurs (Monsieur),-Nous prenons la liberté d'introduire chez vous par ces lignes, et de vous recommander à un accueil obligeant, M.

Nous l'accréditons chez vous pour la somme de £1,000 (nous disons mille livres sterling). Veuillez bien payer jusqu'à cette concurrence l'argent dont M. aura besoin, et nous en débiter sous envoi de ses quittances. Nous vous remercions d'avance, de ce que vous voudrez faire en faveur de M. --, et vous prions d'agréer l'assurance de notre parfaite considération, J. WEBER & CIE.

M.

--, à Londres. Valable pour

mois.

CIVIL SERVICE PAPERS.-IV.
GROUP III.

GROUP III. will be treated in this and one or two subsequent
papers. It is the largest of the groups, and comprises the
British Museum, the Charity Commissioners, the Civil Service
Commissioners, the House of Lords Office, the House of Com-
mons Office, the Copyhold and Tithe Commission, Ecclesiastical
Commission, Emigration Office, Lunacy Commission, Mint,
National Debt Office, Patent Office, Paymaster-General's, Record
Office, and General Registry Office.

Specimens of some of the examination papers that might be set to candidates for offices in this group are annexed, in continuance of the plan announced at the beginning of the series. The importance of dealing with these papers in the manner there suggested cannot be exaggerated. They should be not only worked out as carefully as if the student were actually about to stake his career on the solution of them, but care should be taken to secure their correction by some able person. Such a person might also be induced to frame other papers from the specimens, and these fresh papers should be inde fatigably worked out. Where no such friend is at hand, the best way for a student is to arrange to work the papers conjointly with some one else in his own position; that is to say, each student should work out the questions to the best of his ability, and then compare his answers with those of his fellow. Should they, having worked thus independently, arrive at the same result, the probability is strong in favour of the answer being right; should they differ, there will be good exercise for both in finding out which of them is wrong. There can be little difficulty in working out the arithmetic papers by this method. A little more trouble may be occasioned by verifying historical and geographical and such-like matters; but there will be found in the various manuals which have been published,

and which are well known, sufficient information to meet the requirements of all.

1.-BRITISH MUSEUM.

This office, at the Museum in Great Russell Street, is charged with carrying out the administrative detail of the duties of the trustees for the Museum. Patronage in the three principal trustees, who are the Primate, the Lord Chancellor, and the Speaker of the House of Commons. Limits of age of candidates-assistants, 18 to 25; attendants, 18 to 40. The attendants, whose duties are in the library and reading-room, and who bring books to readers upon requisitions being made for them, are examined in

1. Writing from Dictation.

2. Reading.

3. Elementary Arithmetic.

Assistants (the clerks are so called) are examined in

I. ASSISTANTS.

1. Writing from Dictation.

2. Arithmetic (elementary).

3. English Composition.

4. Précis.

5. Geography.

6. British History.

7. Two Languages besides English, one of which must be either Greek or Latin.

II. JUNIOR ASSISTANTS.

1. Writing from Dictation.

2. Arithmetic (elementary).

3. Précis.

4. Translation from one Ancient or Modern Foreign Language. Salaries:-Attendants, £60 to £120, by annual increments of £3, £1, and £5, according to the class. Transcribers (who are examined in the English language and two foreign languages, in addition to the subjects prescribed for attendants) receive £90 to £150 a year, by annual increments of £10. Assistants receive £150 to £400 a year, by annual increments of £10, £15, or £20, according to class. The prize of the office is the principal librarianship, to which is added the office of secretary, bringing to the holder, in addition to a good position in the literary, scientific, and social world, a good house in the Museum and £1,200 a year.

2. THE CHARITY COMMISSION.

This office is in York Street, St. James's Square. It is charged with the detail of the duties thrown upon the Commissioners by the Act of Parliament which, in 1853, empowered them to deal with lands and money left for charitable purposes in such a way as would most thoroughly promote the objects of charity without reference to the special objects named in the bequests. Patronage in the Commissioners. Office staff small. Thirdclass clerks get £90 to £150, by increase of £10 a year; secondclass clerks get £160 to £280, by £15 a year; first-class clerks get £300 to £500, by £15 a year. Inspectors get £800 a year; and these appointments, with that of the secretary, worth £800 a year, constitute the prizes of the office. Subjects of examination:

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5. Geography.

6. History of England.

7. Latin.

8. French, or another Modern Language.

II. SUPPLEMENTARY CLERKS.

1. Handwriting and Orthography.

2. Copying into Forms and Registers.

3. Indexing.

4. Arithmetic (including Vulgar and Decimal Fractions). 5. English Composition.

III. OFFICE-KEEPER, MESSENGER, AND PORTER.
1. Handwriting and Orthography.
2. Arithmetic (elementary).

Salaries--Supplementary clerks, £80 to £200, by £5 a years. junior clerks, £100 to £250, by £10 a year; senior clerks, £300 to £500, by £15 a year; messengers, £60 to £80, by £2 10s. a year. Prizes of the office-Registrarship, with £600, secre taryship, with £800.

4. HOUSES OF PARLIAMENT.

The educational tests in the offices of the two Houses are the same. The work done consists in executing all the detail of office work connected with either House, and it is light or heavy according as Parliament is in session or vacation. Patronage in offices of the Commons House is with the Speaker for the Speaker's department; with the Clerk of the House for his; with the Serjeant-at-Arms for his. Appointments in offices of the House of Lords are in the gift of the Lord Chancellor, the Clerk of the Parliaments, and the Usher of the Black Rod Limits of age for admission, 19 to 25.

I. CLERKS, TEMPORARY CLERKS, AND SUPERNUMERARY CLERKS.
1. Handwriting and Orthography.

2. The Power of Accurate Comparison of Copies with Originals
3. Arithmetic (including Vulgar and Decimal Fractions).
4. English Composition.

5. History of England, and of the Constitution.

6. Latin or French.

7. (For COMMITTEE CLERKS) the Elements of the Law of Exi-.. dence.

II. ASSISTANT TO ACCOUNTANT.

1. Handwriting and Orthography.

2. Arithmetic (including Vulgar and Decimal Fractions). 3. English Composition.

4. Bookkeeping by Double Entry.

Salaries:-Junior clerks, £100 to £250, by £10 a year; 25sistant clerks, £300 to £600, by £15 a year; senior clerks £650 to £800, by £20 a year. The prizes are the principal clerkships, with salaries ranging from £850 to £1,000, by annual increments of £25.

5. COPYHOLD, ENCLOSURE, AND TITHE COMMISSION. Office in St. James's Square. Commissioners assist in the enclosure and utilisation of waste lands; in the commutation of tithes, and in arranging for payment of fines to lords of manors. Their work is a purely artificial one, created by Acts of Parliament to meet exigencies arising out of a change in English home policy. There is a great deal of purely profes sional work for surveyors, architects, and lawyers, but the clerical staff is small. Office patronage in the Commissioners Qualifications:

I. CLERKS AND ASSISTANT RECORD KEEPERS.

1. Writing from Dictation.

2. Arithmetic (including Vulgar and Decimal Fractions).

3. Correspondence.

II. ARCHITECTURAL SURVeyor.

The three subjects above, and

1. Designs of Structures and Preparation of Working Drawings.

2. Measurement and Estimate of Builders' Work.

3. Knowledge of Quality and Strength of Materials.

III. PERMANENT DRAUGHTSMEN, ASSISTANT SURVEYORS, AND ASSISTANTS IN THE SURVEY DEPARTMENT.

The three subjects prescribed for Clerks, and

1. Land Surveying.

2. Plan Drawing.

MESSENGERS are examined in Writing from Dictation and Elementary Arithmetic.

Salaries-Assistant record keepers, £80 to £150, by £5 a year; assistant surveyors, £150 to £250, by £10 a year; secondclass clerks, £100 to £300, by £15 a year; first-class clerks, £300 to £500, by £20. Messengers get £60 to £80, by £210

stone of the Permian system; and then come plains of
new red sandstone again, crowned by the escarpment
of the narrow strip of oolite, and by that of the cretaceous
rocks.
This structure explains the course of the larger rivers.
The principal watershed of the country is the tract of
high ground extending from the north of Scotland far
into England; it is nearer to the west coast than to the
east, and therefore a much larger area of country is
drained towards the east than towards the west. All the
larger rivers-with the exception of the Severn and its
tributaries-run into the German Ocean. The plains
which occupy much of the middle and east of England
are traversed by many tidal rivers; and from the nature
of the country, the construction of canals has been a
comparatively easy task.

II. Geological Distribution of Mineral Products.

The modes of occurrence of minerals are in veins or lodes, in regular or irregular beds, and in connection with detrital matters. The consideration of the distribution of minerals will be treated of under these heads.

1. Minerals in Veins.

specimens collected by Count Strzelecki, along the eastern chain of Australia. Seeing the great similarity of the rocks of those two distant countries, I could have little difficulty in drawing a parallel between them; in doing which, I was naturally struck by the circumstance, that no gold had yet been found' in the Australian ridge, which I termed in anticipation the 'Cordillera.' Impressed with the conviction that gold would, sooner or later, be found in the great British colony, I learned in 1846 that a specimen of the ore had been discovered. I thereupon encouraged the unemployed miners of Cornwall to emigrate and dig for gold, as they dug for tin in the gravel of their own district. These notices were, as far as I know, the first published documents relating to Australian gold." ("Siluria.")

Influence of Igneous Rocks in the Development of Minerals in Veins.

Mineral veins occur in igneous rocks as well as in aqueous rocks; but the intrusion of an igneous mass among stratified deposits appears to have rendered their lodes richer than when conditions otherwise similar obtain.

Though it is difficult, in the present state of our know- Gold is usually found in a quartz matrix, traversing ledge, to ascertain the laws regulating the deposit of palæozoic shales, chiefly those of the lower Silurian metalliferous matter, yet we are able, from general ob- epoch; and the auriferous lodes are frequently richest in servation of the geological structure of the earth, to say the vicinity of eruptive rocks. But the precious metal that here search may be made for minerals with some is found also in secondary rocks, such as those of Calihope of success, and that there exploration will be futile.fornia, Peru, etc., yet under circumstances exceptional to Hundreds of thousands of pounds have been expended in the opening up of mineral districts; a large proportion of the sum utterly without profit.

Great Britain possesses a rich supply of minerals; we have gold, silver, copper, lead, tin, zinc, antimony, nickel, cobalt, bismuth, uranium, chromium, and other of the rare metals, besides vast stores of iron; our coal beds are enormous, and earthy minerals are in great variety and value. Statistics show that in Great Britain 350,000 persons are actually engaged in mining operations, exclusive of quarries of all kinds, and that the produce is of the minimum annual value of £40,000,000. The lodes from which we derive our chief supply of metals are almost wholly confined to paleozoic rocks. Their occurrence may be sketched as follows:

The Silurian formation in North Wales, in the Isle of Man, in Cumberland, in the lead hills of the south of Scotland, in parts of the Highlands, and in parts of Ireland, contains metalliferous veins which yield gold, ores of copper, lead, silver, antimony, arsenic, and

zinc.

The rocks of the Devonian formation in Devon and Cornwall contain rich tin, copper, and lead lodes.

The carboniferous limestone in Derbyshire, ranging up to the north of England through Cumberland and the adjacent counties, also of the Mendips, and in Devon, is the chief depository of our lead ores. The same formation contains large and rich deposits of hæmatite, an ore of iron, as in the Forest of Dean and Somersetshire.

Throughout the world, all the metalliferous lodes, with some peculiar exceptions hereafter to be mentioned, occur in stratified or the associated igneous rocks, not newer than the Permian. It is thus that one generalisation in the inquiry is arrived at, viz., that of the period during which the lodes carrying our richer metals were filled. Geology, like the more exact sciences, is capable of advancing philosophical inductions to very important results. Sir Roderick Murchison was enabled in 1844, from the study of the gold-bearing tracts in Russia, to predict the discovery of gold in Australia. Having," writes Sir R. Murchison, "in the year 1844, recently returned from the auriferous Ural Mountains, I had the advantage of examining the numerous

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the usual mode of association of gold. It appears that where certain igneous eruptions, diorite especially, have penetrated the secondary strata, the latter have been rendered auriferous for a limited distance only beyond the junction of the two rocks; and it is concluded that all secondary and tertiary deposits (except the auriferous detritus of the latter), not so specially affected, never contain gold.

The lodes carrying copper and tin in Cornwall and Devon are richest about the junction of the killas (local name for the slaty rocks of the Devonian formation in this district), and the bosses of granite, and where they are intersected by granitic dykes, termed elvans. It is worthy of remark that these metalliferous veins have a course or strike nearly east and west, and that these phenomena are not confined to this area, but are exhibited in Saxony and elsewhere.

Other examples might be adduced, but these will suffice to show that intrusive rocks influence the metalliferous richness of veins.

2. Bedded Mineral Deposits.

These include coal and iron ore of primary importance; and salt, gypsum, cement-stones, coprolites, iron-pyrites, bituminous shales, etc., of secondary value.

(a.) Coal occurs in many formations; it has been mined for upwards of a hundred years at Brora, in Sutherlandshire, in rocks of the oolitic epoch, and is worked at Bovey Tracey, Devonshire, in Miocene beds. An anthracite occurs in the Devonian rocks in Spain; there are good workable coals of the age of the trias in Virginia and Hindostan, and of that of the lias in Hungary; and less valuable coals, chiefly brown coals, occur in tertiary strata in Austria and other parts of Germany. But by far the richest and largest supplies are drawn from the carboniferous system in Great Britain, Belgium, United States, Nova Scotia, Australia, etc.

In Great Britain no coal is found below carboniferous strata, but it does occur in newer strata. In the midland and south-western counties of England, and in South Wales, it is confined to the true coal measures underlain by the millstone grit, locally called the "farewell rock," because, in the language of the miner, when that rock is reached, one bids farewell to the coal. But in the north of England and in Scotland workable coal seams occur

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