On leaving Dublin, we travelled northwards, for the purpose of examining the carboniferous rocks, and visiting the magnificent collection of fossil-fishes in the museum of the Earl of Enniskillen; we then journeyed south for Killarney and the Dingle district, but as it may be more convenient to the reader to travel geologically, we will reverse the order of our journey, and visit the Upper Silurian and Old Red Sandstone districts before we examine the carboniferous deposits.

The lower Cambrian rocks of Wales, of which the Oldhamia-schists of Ireland are believed to be the equivalents, pass upwards by insensible gradations into the Lingula-flags, to which they are altogether conformable. The Lingula-flags are reckoned to be four or five thousand feet thick, and the Llandeilo or Builth-beds, which cover up these, are probably as thick; but geologists are, as yet, uncertain whether they possess in Ireland any true equivalents either of the Lingula-flags or of the Llandeilo and Builth deposits. There are, however, fossiliferous rocks of the Bala and Caradoc age in Ireland similar to those which, in Wales, succeed conformably to the Llandeilo and Builth beds, and they may be examined at Courtown, in the county of Wicklow, and again at Tramore, south of Waterford. They are unconformable to the rocks below, which are undoubtedly Cambrian, and thence, we imagine, has arisen the suspicion that the Lingula-beds and Llandeilo-flags have never been deposited in Ireland, or that if they were, they have been denuded and swept away before the deposition of the Bala or Caradoc strata.

In a magazine devoted especially to the propagation of Geological knowledge, it seems no infringement of its space, no deterioration of its value, tha t some pains should be taken to aid the student in his early efforts, and to disperse broadcast some useful elementary information, which may prove to the mass at once a source of instruction and of enjoyment, and so, by clearing the road to future and higher studies, may foster a dawning taste, and ultimately prove the means of adding many volunteers, and not unlikely even some brilliant master-minds to the ranks of Geologists, that otherwise, deterred at the outset, might perhaps have turned their attention and talents to some more accessible, if not more congenial study.

Who does not feel some interest in the past history of this beautiful world—the scene of our labours and of our loves—of our successes and of our failures—the stage of our existence and the tomb of our dust ? If the animated creations of the past were dumb brute animals, still the earth was green and gay with trees, and plants and flowers—the hu m of insects vibrated on the summer's air, and the snows of winter covered the ancient lands with their hyemal mantle—the tides of ocean rose and fell, and the world went rolling on through time and space, through years and seasons. There were earthquakes the n and blazing volcanos—and winds and storms—great waves and merry dancing ripples on the sea.

A Man would see but little of the reality of the world if he shut himself up in his house, and only gazed out from the same window; he would learn little more if he contented himself with alternately gazing upon the scenes passing around him, from the windows of every storey. So a geologist, in limiting himself to the study of the rock-masses of a circumscribed area, would never, by the utmost perseverance, in going continually over the same ground, attain to a perfect understanding of the subject of his study. He must go abroad, either in his own person or equivalently, by making himself acquainted with the travels and labours of others. Our knowledge of the ancient conditions and relations of the oldest rock-masses would not be complete if we limited our investigations to those isolated patches in our own country, which, however important, are still only a part of that great whole, more important traces of which are to be met in regions far away. Thus those very old—indeed, primitive sedimentary rocks, represented in the British Isles in a fragmentary manner, as by the younger or bedded gneiss of the Scottish Highlands, assume in Canada and the Arctic regions proportions of great extent, and consequently, of far greater value. Far back in the obscurity of the past, as must be placed the birth-time of these primitive land-masses, we seem, in our first investigations, plunged in interminable ignorance, like the explorers of some vast subterranean cave in impenetrable darkness.

The case now to be detailed is one which was investigated at Malmsbury, in Wiltshire. At this place the worthy burgesses to whom the land had been bequeathed by king Athelstan had undoubted evidence that a shaft had been sunk for coal on the land in question. This operation was actually performed about a century ago, and, in order to pay the attendant expenses, the whole of the timber from a large estate was felled and sold. Tradition said that “the coal had been arrived at, but, in reality, those engaged had been bought off by some proprietors in the Bristol coal-field, for fear the new district coal should come in competition with theirs.” But, besides evidence of this kind, about two pounds of Lignite was submitted to my inspection, with the assurance that it burnt like good coal; and the argument founded upon this pseudo-coal was as follows:—“This coal is about two inches thick at about 20 feet from the surface; how thick, therefore, may we not expect it at a hundred yards?” But for fear this should not be deemed conclusive, a bill of sale of some land in the district, many years before the date of this examination, was produced, on which was the statement that “Mining rights were reserved.” But I should state that upon inquiry it was found that the said land belonged to the Crown, and I believe that in all Crown lands there is a reservation made of mining rights; thus this, it will be perceived, was no evidence whatever of the presence of mineral matter. These, then, were the foundations upon which the burgesses relied; now for the geological examination.

But what are the silent voices of the past saying—for what have the wonderful and mysterious powers of nature for so many ages been labouring? Where, through all the strange mysteries of the past, is the finger of God pointing? To MAN, and the world that is his. Look at all the appropriations of every kind of organic and inorganic matter to such varied and different purposes by our race, and can we divert our minds from contemplating the vast time and the numberless operations which have assisted in the elaboration of the materials necessary for our comforts or our wants? Past and present creations alike show that animals fitted for each peculiar condition of our planet have existed at every period; but of all those classes which have passed away, or of those which exist, there are none which have not been limited in their geographical range, none to which a considerable other portion of this world has not been useless and unserviceable. Is it so with man? The stars of heaven—how many ages old!—tell him the track of the world he lives upon; mysterious magnetism guides the slender needle by which his freighted ships are safely steered from shore to shore; the very lightning is his messenger. The coal and iron of his mighty engines are ages old; the clay of the bricks of which he builds his houses, and the marble of the statues with which he adorns his palaces, have passed through ages of preparation; innumerable and diversified as are the materials of the earth, has he not a use for them all, from the lowermost granites to the uppermost surface-soils?

The object of this essay is to view the science of Geology on a more extended scale than is generally attempted in popular treatises; not dwelling on matters of detail, but regarding physical principles and fundamental propositions with those logical sequences by which remoter conclusions are arrived at.

“But how, it may be asked, is the student or mere general reader to enter upon these larger views of the subject without a previous acquaintance with its details? And, doubtless, if any one would make himself an accomplished geologist, and prepare himself to enter fully into the more profound investigations of the science, he must gain a knowledge of its phenomena with a certain degree of detail; but the more complete a science becomes as a science of observation, the less necessary is it for the philosopher who would solve its physical problems to become himself an observer. Newton and Laplace troubled themselves little in looking through astronomical telescopes. They took their facts on the authority of others. And so, also, the general geological reader may accept the facts established by the observations of the field-geologist, when he would acquaint himself with the conclusions of those who have endeavoured to solve the physical or palæon-tological problems which the science presents to us.”

As the summer approaches, many of the readers of the Geologist will be preparing for their vacation-rambles; and should any think of visiting our Sister Isle—“Old Erin”—the following notes may be of service.

We started on a bright August morning of last year for the meeting of the British Association for the Advancement of Science, held in Dublin, and with the intention of travelling over as much country, breaking as many stones, gathering as many plants, and catching as many salmon as time and circumstances would permit. We were fortunate in our combination of naturalist and sportsman, but as these notes are intended solely for the naturalist, we leave our “salmon struggles” unrecorded—at least in the pages of the Geologist.

We travelled by Conway and Bangor to Holyhead, and as it was blowing a gale of wind when we arrived, we determined to wait until the sea was calmer, and, in the meanwhile, to visit the Cambrian rocks of Anglesea.

We never saw a more instructive example of contortion and twisting of rocks than is displayed at the South Stack Lighthouse, of which a good sketch is given in Sir R. Murchison's “Siluria.” It is indeed a rugged coast; and the terrible Bay of Caernarvon to the south has been the locale of more shipwrecks than any other in the British Isles. We visited the grand quarries of quartzite, worked on a gigantic scale for the great breakwater. Here, as the geologist approaches the quarry from Holyhead, is a greenstone-dyke traversing the quartzite with a singular vein of pink decomposing felspathic rock.

After the al fresco dinner of the “Worcestershire Naturalist Club,” under the Sorb Tree, in Wyre Forest, I and Mr. Baxter of Worcester, well known for his botanical acumen, started for the Ludlow promontory, via Cleobury and Caynham. I copy from my note-book the following geological facts—some may be of use to the definer of the limits of ancient life-periods; others, deficient in value for such purposes, may save future explorers time and trouble in working up the district.

I arrange them in the order of their occurrence.

The “Brownstones” of the cornstone series are finely quarried a mile east of Cleobury; very fine rippled-marked slabs may be obtained, and ichnites (fossil footprints) should be apparent, it being an equivalent bed to the one in which they occur at Puddlestone, Herefordshire.

The curious outlier of the “Forest Coal-field,” on which Cleobury stands, has been fruitlessly sunk into for coal this year; another proof that the geologist is not “abroad” in the land, no bed in the whole coal-field having paid expenses, and, in some instances—this I find among the number—the Old Red has been reached without coal being met with.

The south end of the Titterstone Hill, presenting a fine escarpment of mountain limestone to the valley, is very barren of fossils. I could not meet with or hear of any of those interesting fish-jaws, spines, and palatal teeth, so numerous along its northern sides at Oreton and Farlow.

At the extremity of a pretty bay, on the coast of Yorkshire, stands the town of Whitby, known to every geologist for the numerous treasures of organic remains which the Lias beds, there outcropping on the shore, have furnished at various times.

Nor is Whitby wanting in historical associations. It was there, in Anglo-Saxon days, stood the far-famed monastery of Streones-healh, of which St. Hilda, the relative of Northumbria's powerful monarch, Edwin, was the abbess. It was there the famous council was held to decide the keeping of Easter (A.D., 664); it was on those rugged shores of the North Sea that the early stand was made by Colman on behalf of the native religion against the then increasing dominion of the Romish Church. It was there reposed the remains of Edwin, Oswy, Aelfleda, and of the Saxon Hilda herself. Associated with its monastic rule were many of the famous men of the olden times—Bosa, Aetla, Oftfor, Wilfred, and Cædmon, to whom Bede says sublime strains of poetry were so natural that he dreamed in verse, and composed in sleep that which he penned on awaking. And the history of Whitby is pleasingly associated with its geology by the legend of its saint.

The Boulder Clay is so seldom exposed in the neighbourhood of London, that I think it may be desirable to point out a new locality where I have met with it and where it may yet be seen, especially as I have just found some points, connected with its position at this place, which are of rare occurrence. The new line of railway from Watford to St. Albans passes chiefly through gravel and chalk. At one place, however, called Bricket Wood, about midway between those towns, there is a cutting of some length, and twenty to thirty feet deep, entirely through the Boulder Clay. The superposition of this clay, with regard to the gravels of the London district, is seldom to be determined; the cutting itself throws no light on this subject, or, at least, nothing very definite. But a ballast pit has recently been opened at the Watford end of the Bricket Wood cutting, and immediately south of the line, which exposes a section of much interest. The Boulder Clay has there almost thinned out, leaving but a seam one to two feet thick, whilst both above and below it is a thick bed of gravel. The lower sandy gravel, which consists chiefly of sub-angular flints and flint pebbles, with some quartz, sandstone, and old-rock pebbles, with subordinate seams of whitish sand, has a clean, washed appearance.

The Palæozoic System comprises the earliest fossil-bearing strata. These have collectively a great thickness, and are of various mineral characters, being argillaceous, arenaceous, and calcareous, generally indurated, and occasionally metamorphosed.

As a general rule, these strata appear in the western and north-western districts of Britain, and, to a considerable extent, in the mari-time districts of Ireland. The rocks of this system contain the chief metaliferous workings, as in Cornwall, North Wales, Cumberland, Scotland, &c. The upper portion, namely, the Carboniferous, affords the chief source of our lead-ores which occur in the limestone of Derbyshire, Flintshire, and Cumberland; and the associated shales and sandstones, forming the Coal-Measures, contain the well-known extensive deposits of fossil fuel and iron-ore.

The palæozoic strata are numerous enough and sufficiently distinct among themselves to form several series. The first or lower of these comprises the Cambrian and Silurian; the middle is the Devonian; and the uppermost includes the Carboniferous and Permian.

The lower portion of the palæozoic system has two great groups of rocks; the lower one is named Cambrian by the Rev. Professor Sedgwick,—from its great extent in Wales;—the other is called Silurian by Sir Roderick Murchison, on account of the typical strata of this group having been worked out by him in the country once inhabited by the Silures,—the border-counties of England and Wales, where the group is extensively developed.