SKETCHES. IN GEOLOGY.

West Coast Times, Issue 624, 24 September 1867, Page 4

SKETCHES. IN GEOLOGY.

LEOTTTBE DELITEBED BY ME SOUTH, AT THE Covet House, on the 12th Sept., 1867, In aid of the Funds for forming a Library in connection with the Rokitika Literary Society* The subject I am about to bring before you this evening, is one which, carrying us back into the deep recesses of the past, conveys to our minds the impressive fact that there were seas and shores as well as other elements existing at a period long .anterior to human tradition. Who that has met with " Longfellows' Evangeline" has failed to be struck with a certain feeling of solemnity at the grandeur of the Poet's description :—: — " This is the forest primeval * * * The muimuring pines, and the hemlocks, Bearded with moss, and in garments green, Indistinct in the twilight— stand like Druids of old, with voices sad and Prophetic— #••*•• Loud from its rocky caverns, the deep Voiced neighboring ocean speaks, And in accents disconsolate answers Thewail of the forest — the Forest Primeval." How much more overwhelming is the thought of what was the Earth Primeval, the records of which may be said to have been written on the leaves of Eternity, only recently unfolded to our view, and that even iv the present day but partially. Geology, popularly defined, is a treatise or discourse on the. Earth, having its derivation in Ge, the earth, and logos, a discourse. It is a term which admits of a wide interpretation, suggesting to the mind enquiries into the formation and original condition of the Earth — into the ' successive changes or modifications which it has undergone, and the agencies by which I they have' been effected. Just as astrouomy includes within itself the whole science of the heavenly bodies, so Geology, iv its extended lense, is the science of the Earth ; including within itself all the sciences that treat of the inorganic matter of the Earth, the living beings formerly inhabiting it, as well as their order and condition. — In pursuing such enquiries we soon discover proofs that the external parts of the Earth were not all produced, in the beginning of things, iv the state in which we now behold them ; but, as that tminent modern Geologist, Sir Charles Lyell, observes :—": — " Under a great variety of circumitances, and at successive periods, during each of which distinct races of living beings have flourished on the land and in the waters, the remains of these creatures still lying buried in the crust of the Earth." I may here premise that a science is practically valuable, just in proportion as its facts have been discovered, and its laws established and studied ; for so long as we are uncertain whether a known result has proceeded from a definite cause, we are unable to apply the fact to the elucidation of phenomena as they are opened up to us, or present themselves. I shall make an attempt to bring this important and most interesting science before you this evening, in ianguage as plain and unscientific as I can use, avoiding all such abstruse terms as can practically be dispensed with, and this for two reasons — Ist. — Because my learned and scientific hearers can themselves supply what I dispense with ; and, secondly — That those unacquainted with the subject, may be enabled the more easily to comprehend, and follow me; and may be also induced, as I hope, to take the science up as a recreative study, which will, believe me, amply and profitably repay their researches. It is a far less difficult task for the Lecturer to collect together and read, then, when read, for his hearers to understand and follow, with a sustained interest, all the abstruse words employed by geologists in connection with this science. Geologists anglicise a number of words derived from the Greek, Latin, Italian, French, German, and Swedish, which, although anglicised, remain difficult, except to the student. The aim of the Lecturer, in a course such as these, should be, as it seems to me, simplicity, so that his hearers may go away and think. "I read fourteen hours a day," said a proud working student to a famous scholar. " Indeed, Sir," was the reply, " and pray when do you think?" I intend, therefore, to avoid, as far as possible, these tremendously scientific and elongated expressions, as stumbling blocks in the way — like too heavy a meal which impairs the digestion. Where lam obliged to use any such scientific terms, I will explain them as well as I am able, whereat I trust none of my hearers, learned or unlearned, will take offence. But th* enquiring mind, whether learned or unlearned, will never object to he reminded of ■ome of tho most elementary facts of his knowledge. " The human race," says a modern writer (Goodwin), "has been ages in arriving at conclusions now familiar to every child." The men of the sixteenth century were startled when told that the Earth moved. The child is now taught that, and is assured that it is a little- less than 6000 years old ; and that it was made in six days ; and that it right, as everything is right which proceeds from the Bible — Bishop Colenso notwithstanding. It has been often and repeatedly urged that the study of Geology brings the student in conflict with Theology, in other words, that geological revelations are opposed to the Bible. It is not so, however, with the Christian Geologist, for there is no more sublime study under the sun than that of Geology to the believing mind. We must | pity the sceptic geologist who looks to original causes disconnected with the Great Author of our world, and our existence ; and compare him very unfavorably with his fel- i low-worker the Christian Geologist. Coleridge, | during an argument, once asked an atheist "where he got the idea of that God whom he denied?" which particularly puzzled his opponent. I apprehend we should never lose sight of the fact that the Bible was evidently not intended as an exponent of physical science, but rather as an elucidation of God's word. Against the direct manifestations which Geology opens up of the infinite power and goodness of a Great Creator the atheist has exhausted his energy, without effecting a single breach in the battlements "Each stroke of his hammer," say 3 George Taylor, " brought out the fire of some latent truth ; and every step he advanced into the unexplored territory, introduced him to additional witnesses — the lightnings of heaven reprimand him, while the ocean thunders back Wb falsehood." Truly may it bo said, that the believing geologist finds miracles in atones. Geology may be termed the first chapter in Natural History, and the first volume of Natural Taeology, and happy is he who in this spirit shall read, mark, learn, and inwardly digest it. Phillips says that it would provoke a smile to recount the singularly contracted notions, which have until lately figured in works on Geology. Indeed the theories which have from time to time been advanced by the ancients regarding the origin and development of the Earth, show, that it was Cosmogony, or an enquiry into the origin of the Earth, and not Geology, which was the subject of the old traditions of Phoenicia, Chaldea. Eevr>t and China. The Cosmogony of the Babylonians caught the attention of Niebuhr. According to it the world began with a chaotic darkness, which was a fluia, and inhabited by swimming animals of the strangest forms. In the works of early Greek authors there re passages wliich seem to prove that even thr. 1 . G-sology had «xoited tomt *tt«ntion : at |

that period, however, only a very small por- | tion of the Earth's surface could have been known to the inhabitants of any one couutry, and little progress could have been made in the pursuit of geological facts. In the works of such aarly writers as Ovid and Pythagoras, we may, however, trace allusions to the changes of the relative levels of land and sea ; the separation of islands from the main land by the power of earthquakes ; the displacement and limited duration of volcanic rents — such as Etna; the degradation of land by the action of atmospheric agency ; the submersion of land which had been formerly inhabited ; the production of new land, and the occurrence of marine shells far from the pre- | sent seas. Ingenious G-reece added a considerable refinement in the nature of the ! fictions by which it was sought on vague analogies to supply the want of fair inductions. In the pages of Aristotle, general propositions were stated, involving frequent! displacements of land and sea, periodical revolutions, and systematic changes at every point. He remarks — "As time never fails, and the universe is eternal, neither the Tanais or the Nile can have flowed for ever — the places where they rise were once dry ; and there is a limit to their operations, but there is none to Time. So also of all other rivers, they spring up and they perish ; and the sea also continually deserts some lands, and invades others. The same tracts, therefore, of the Earth, are not always sea, and others always continents, but everything changes in the course of time." Scattered thoughts are to be met with in Herodotus and Strabo as well, bearing upon this subject, but nothing approaching to a regular geological system. Fifteen centuries elapsed after the time of Strabo without producing any geological work of value, except a few details by Omar, an Arabian writer. Italy, (he faithful mother of modern physical science, offered, in her volcanic cones, j ranges of mountains, and shelly marls at their bases, the most attractive points of the intellectual activity of the precursors and contemporaries of Galileo, Fracabtoro, and Georgius Agricola, in the sixteenth century. These carried on discussions concerning the origin of certain rocks and fossils found therein ; and discussions were taken up iv other 'countries by Stento, Plot, Walton, Woodward, Schenchzar, and Palissey ; but as soon as the arguments employed made the smallest approach to an apparent disagreement with the mosaic account of the deluge, the science was shunned and scouted in many influential quarters, and the writings of Quirini, Hooke, Ramarizzini, Leibiutz, Moro, Buffon, Linnoous, Whitehurst, and other observers, in the seventeenth and eighteenth centuries, could scarcely bear up against the prejudice thus excited. The discovery of fossils in dry and elevated situations was the great point of discussion. There can be but two hypotheses concerning it — either in the shelly bed of the sea Las been raised, or the ocean has abandoned its ancient places. To expound one or other of these theories, the speculators' works before referred to were broached by their respective authors. Very little was done until the present century in studying Geology as an inductive science — that is, by reasoniug from fads, instead of theories, or hypotheses. Among the few who did so was Lehman, who, in 1756, proposed an intelligible classification of rocks into three groups, according to their properties. Pallas, who. in 1779, drew attention to the difference between primary and secondary rocks; Warner, who, in 1796, propounded the doctrine of formations universally succeeding each other in a settled order of time ; and Whitehurst, who somewhat earlier gave a distinct account of the stratification of Derbyshire ; and a few other writers. But it is Mr William Smith who is justly regarded, and indeed I may say acknowledged, as the father of modem Geology. This gentleman, who was a Surveyor, and Civil Engineer, bad his attention drawn in 1787 to the obvious distinctions iv the soils and subjacent strata of certain parts of Oxfordshire and Warwickshire, which occupied with regard to one another a certaiu geographical relation. In 1790 and 1791 the same relative position of the same strata was forced upon his attention in Somersetshire, with the addition of a series of coal strata below oolite (which latter is formed of masses of limestone, like small eggs, collected round shells or portions of. organic matter), Lias, which" is tho thin bedded limestone at the base of the oolitic series in Somersetshire, and red marls, with which he was previously familiar. Following out this clue, he found that one general order of succession of the strata could be traced throughout tho island, with a general dip to the east, or south-east, the result was a Geological Map of England and Wales, drawn previously to 1801. In subsequent examinations he ascertained the important fact that fossils were definitely located in the rocks ; each strata having its own peculiar species wherever it occuiTed, which could thus be identified when in detached masses and in distant localities. Now, although a few researches had been made by other enquirers concerning fossils, it is unquestionably to Mr William Smith that we owe the important doctrine, that during the formation of the stratified crust of the Earth, the races of animals and plants were completely changed. Thus the stratified rocks (so beautifully called by Dr. Mantell the coins of creation; became, ns it were, the museum of a distinctive age of the world, containing, as it does, a peculiar suite of exuvia>, or the remains of the creatures then in existence. The groundwork being thus laid, Fossil Geology soon became an important study in the hands of Cuvier, Bronguiart, Dashayes, Lyell, and many other enquirers, who made it a particular branch of study to determine how far fossil species correspond with, or differ from existing species. What was dimly seen by our forefathers is demonstrated to vs — theirs was the unsolved problem, ours the solution. The study of Geology as a science has cleared away tho mists which hung over the speculations of the ancients, and beholding Nature face to face, we are enabled to comprehend the order of her revolutions with the clearest accuracy. The manner in which the geologists have been able to restore the history of the primeval Earth, affords one of the most brilliant triumphs of the human intellect, Chemistry, Botany, Mineralogy, aud Physical Geology, have all aided in unfolding this enigma ; but it ! is perhaps to comparative anatomy, which enables us to identify an animal by a single bone, that the principal merit is due. A laborer, in blasting a limestone rock, or sinking a well, throws up a bone which hiis been buried there for millions of ages. This is looked upon with wonder, and he supposes that it must have been there ever since the flood ; but to the eye of a Cuvior, that bone suggests a whole animal, with all the conditions necessary for its existence. The huge mastordon , the megatherium, the paleotherium, the ignamorlon, and pterodactyle, with numerous others, are thus restored, as it were, to our natural history, live again and are resuscitated in our literature. Nor is this all ; for where there are no bones to bear their silent but significant testimony, the strata frequently contain the impress of their former inhabitants. In a thin bed of fine clay occurring between two beds of eandstone this evidence is often preserved, tho ripple mark, the worm track, the scratching of a small crab on the sand, and even the impression of a rain drop so distinct as to indicate the direction of the wind at the time of the shower, and the ebbing of the tide, these, and the footprints of the bird aud reptile are all stereotyped, and offer an evidence which no argument can gainsay, no prejudice resist, concerning the natural history of a very ancient period of the Earth's life. Yet the wave that made that ripple mark has long ceased to wash those shores, for ages has the surface, then exposed, been concealed under great thickness of strata; the worm and the crab, up to a certain period, left no solid fragment to speak of their form or itructure ; the bird left no bone that hud

then been discovered, the fragments of tho reptile were small, imperfect, and extremely rare ; still, enough is known to determine the fact, and that fact is all the more interesting and valuable from the very circumstances under which it is presented. Sj:ctk>x 11. When Chao3 ended in Creation ; When " the E-u-lh was without form and void," " 3so gentle breeze Had stirred the air, Or swept the seas At the hour of prayer." The earliest theorists in England, without going into the subject of the original supposed structure of the Earth, framed some idle theories, giving plausibility to their creed, that the Noachian deluge was the cause of all the past changes on the Earth's surface. Differing somewhat in detail, they all agreed in the notion of an interior abyss from which the waters rushed, breaking up, and bursting through the crust of the Earth, to cover its surface, and whither after the deluge they returned again. Such a theory as this has been proved, oi 1 , at all events, nearly proved to demonstration, to be baseless. It is not water we have to contend with there, but fire. It is not a sea of water that presents itself to the discovery, but the rather a sea of fiery igneous matter. All the geologists and geographists of tho present day, after studying the structure, the history and the occurrences befalling the Earth, teach at present the doctrine of central heat. I The plauet Earth is, like all the othors, of celestial origin. " The planets are formed," j says La Place, "by the condensation of | zones of vapours," aud Buffon writes — " the j terrestrial globe lias precisely the form that would be taken by a fluid globe, tnrniug upon itself with the swiftness which, as we know, belongs to the globe of the Earth." Thus the first consequence wliich flows from this incontestable fact, is, that the matter of the Earth, of which our Earth is composed, was in a state of fluidity at the moment when it took its form, that is, it was possessed of a quality which in bodies is opposite to solidity. It was a mighty mass of liquid fire. In the course of time the outer portions became cold, and thus was formed a crust or casing to the fiery mass. The cold lava had become a rock, and this rock was granite, the parent of all rocks, and the foundation of this whole creation. This granite is found iv all quarters of the world, and although it is often buried so deep under the overlaying strata that man has never been able to penetrate through the enormous crust ; on examination of the mountain chain, it has been observed to be upheaved by some hidden eternal force, wliich has broken the strata lapping it (as it were, like bands), and forced itself into notice. This is the action of the igneous wave of molten rocks causing the earthquake, and the granite to be raised or uplifted. It is in this manner found in abundance in the Himalayan, the Carpathian, the Ural, Caucasian, the Andes, and Eocky Mountains, in Scotland, Cornwall, Devonshire, and indeed, as we have said before, in all parts of the world. The various kinds of granite are composed generally of three ingredients — felspar, quartz, and mica; but in some varieties the quartz is wanting, and in others the mica, which latter ingredient is supplied by hornblende, a mineral of a dark green or black color, an ingredient of trap rocks, or plutonic rocks, i.e., those formed by the action of heat. Q-ranite trap and volcanic rocks are so called, being produced from below in a fused state. It is thus that the varieties of granite are formed. Some kinds are red, others dark, whilst some are almost white. The9o differ also iv hardness or durability. Some kinds decompose almost as soon as they arc exposed to the air ; and others will last for thousands of years, without showing the least sign of decay. Occasionally the hard and soft kinds are found intermingled, and when tho softer parts have become decomposed, a natural curiosity is formed like the famous Luggin stone at the Land's End, Cornwall, which is left by such action, balanced. Phillips, the eminent geologist, the reader in Geology in the University of Oxford, puts •his conclusions of the greatest probability wliich the subject just treated of admits, into three heads, as follows : — Ist. — That the superior density of the internal pai'ta of tho Globe is occasioned by the accumulated pressure which they have to sustain. 2nd. — That the cflects of this pressure in condensing the internal parts of the Globe would be far more considerable than they are, were they not resisted within, by some general antagonist force, such as the expansive power of heat. 3rd. — That the Earth's spheroidal figure lias been attained in consequence of its having formally been entire fluid during rotation on its axis, and is preserved because the internal arrangements of its materials, whether solid or fluid, is in equilibrjos, with the velocity of its rotatory movement. To he continued. Reasons why a ship is called she : Because man knows not the expense till he gets them. Because they are useless without employment. Because they look best when well rigged. Because their value depends on their age. Because they are upright when in stays. Because they wear carps and bonnets." Because they are often painted.