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CHAPTER VI.
EIGHT YEARS OF QUIET PROGRESS

Both courses of lectures ended⁶⁶ and the third volume of the "Principles" successfully launched, Mr. and Mrs. Lyell left London in June, 1833, for another Continental tour. During their first halt, at Paris, she was duly introduced to the famous quarries of Montmartre, and had an opportunity of "collecting a fossil shell or two for the first time." Thence they made their way to Bonn, which she had left as a bride the previous summer, and, after another short halt, proceeded up the gorge of the Rhine to Bingen, visiting on the way the ironworks at Sayn, and examining the stratified volcanic deposits on the plain between the river and that town. The Tertiary basin at Mayence was next visited, and from it they went leisurely to Heidelberg. From the picturesque old town by the Neckar they struck off to Stuttgart and to Pappenheim, examining one or two collections at the former place, and the quarries of Solenhofen, near the latter. These were already noted for the abundant and well-preserved fossils obtained in the quarries worked for the well-known "lithographic stone," though the famous Archæopteryx had yet to be found; that strange creature, feathered and like a bird, but with teeth in its beak and a tail like a reptile, which has supplied such an important link in the chain of evidence in favour of progressive development. Thence they travelled to Nürnberg and Bayreuth, visiting on their way the noted caves at Muggendorf, and returned to Bonn by way of Bamberg, Würtzburg, Aschaffenberg, and Frankfurt. In this journey, few localities of special interest were investigated, but, as Lyell's letters show, no opportunity was lost of discussing important questions with local geologists, or of examining sections in the field. But on the way back to England through Belgium a halt was made at Liége, to inspect Dr. Schmerling's grand collection of cave-remains. It is evident, though but a short notice of it has been preserved, that this visit kindled an enthusiasm which was to produce important results in later years. Lyell writes (to Mantell, after his return to England): —

"I saw at Liége the collection of Dr. Schmerling, who in three years has, by his own exertion and the incessant labours of a clever amateur servant, cleared out some twenty caves untouched by any previous searcher, and has filled a truly splendid museum. He numbers already thrice the number of fossil cavern mammalia known when Buckland wrote his 'Idola Specus'; and such is the prodigious number of the individuals of some species – the bears, for example, of which he has five species, one large, one new – that several entire skeletons will be constructed. Oh, that the Lewes chalk had been cavernous! And he has these, and a number of yet unexplored and shortly to be investigated holes, all to himself: but envy him not – you cannot imagine what he feels at being far from a metropolis which can afford him sympathy; and having not one congenial soul at Liége, and none who take any interest in his discoveries save the priests – and what kind they take you may guess, more especially as he has found human remains in breccia, embedded with the extinct species, under circumstances far more difficult to get over than any I have previously heard of. The three coats or layers of stalagmite cited by me at Choquier are quite true."⁶⁷

Very probably among these human relics was one which was destined to become famous – the skull found in the cave at Engis – for this was described by Dr. Schmerling in his "Recherches sur les ossements fossiles découverts dans les cavernes de la Province de Liége," a book published in 1833. It was found at a depth of nearly five feet, hidden under an osseous breccia, composed of the remains of small animals, and containing one rhinoceros tusk with several teeth of horses and of ruminants. The earth in which it was lying did not show the slightest trace of disturbance, and teeth of rhinoceros, horse, hyæna, and bear surrounded it on all sides.⁶⁸ This relic proved – and since then numbers of similar cases have been discovered – that if the man of Engis were an antediluvian, and his corpse had been washed into the cave together with the drowned bodies of rhinoceros, and other animals,⁶⁹ that event, at any rate, must have corresponded with a great change in the habits of the larger mammalia, for they had been unable to return to haunts which once had been congenial. In other words, the foundation was being laid, now in 1833, for the next great advance in geological science, the contemporaneity of man and several extinct species of mammals, indicating, of course, the antiquity of the human race. To this point, however, public attention was not directed for nearly twenty years. Then various causes, especially an examination into the evidence discovered in the neighbourhood of Abbeville and Amiens by M. Boucher de Perthes, brought the question to the front. But though the controversy was sharp and bitter for a time, it was speedily over, and the question which is still agitated – though mildly and in a sense wholly scientific – is whether man appeared in this part of Europe and in corresponding regions of North America, before, during, or after the glacial epoch?

But the Engis skull is a relic exceptionally interesting. Though the handiwork of primæval man is common enough – rudely chipped instruments or weapons of flint or other stone, worked portions of bones and antlers, and such like – yet his bones are far less common than those of other mammals, and, most of all, skulls are rare. Professor Huxley, in his work from which we have already quoted, states that Dr. Schmerling found a bone implement in the Engis cave, and worked flints in all the ossiferous Belgian caves, yet this was the only skull in anything like a perfect condition, though another cavern furnished two fragments of parietal bones. Yet from the latter numerous bones of the extremities were obtained, and these had belonged to three individuals. What inferences, then, can be drawn from this skull as to the intellectual rank of primæval man? This question was discussed by its discoverer, and the evidence has been also considered by Professor Huxley. The former thus expressed his opinion, "that this cranium has belonged to a person of limited intellectual faculties, and we conclude thence that it belonged to a man of a low degree of civilisation; a deduction which is borne out by contrasting the capacity of the frontal with that of the occipital region." Professor Huxley sums up a careful discussion of the evidence, in which he calls special attention to points where it happens to be defective, by stating that the specimen agrees in certain respects with Australian skulls, in others with some European, but that he can find in the remains no character which, if it were a recent skull, would give any trustworthy clue to the race to which it might appertain. "Assuredly there is no mark of degradation about any part of its structure. It is, in fact, a fair average human skull, which might have belonged to a philosopher, or might have contained the thoughtless brains of a savage."⁷⁰

The winter of 1833 and the spring of the following year were spent in London. It was evidently a busy, though uneventful, time: a new edition of the "Principles" was being prepared and printed, a paper read to the Geological Society on a freshwater formation at Cerdagne in the Pyrenees, and information collected for a summer's journey. This was to be in a new direction – to Scandinavia – with the more especial intent of studying the evidence on which it has been asserted that the shores of the Baltic had changed their level within recent times. But on this occasion Mrs. Lyell remained at home, as the travelling might occasionally have been too rough for her so we find, in a journal written for her perusal, a full sketch of a tour which proved, as he had anticipated, to be fruitful in scientific results. His first halt was at Hamburg, where, on his arrival, with characteristic energy he dashed off at once in a carriage to examine a section below Altona which he had marked down on his voyage up the Elbe. This is his brief summary: "Cliffs sixty or seventy feet high. Filled three pages of note-book. Saw the source of the great Holstein granite blocks. Gathered shells thrown ashore by the Elbe." From Hamburg he drove to Lübeck, along one of the worst of roads. The primary cause of its badness was geological – a loose sand interspersed with granite boulders; the secondary, the royal revenues; for these largely depended on the tolls paid by vessels on entering the sound, and if a good road had connected the two towns much merchandise would have gone overland, to the king's loss. At Lübeck Lyell for the first time stood upon the shore of the Baltic, and utilised the half-hour before his steamer started for Copenhagen by hunting for shells. As a reward, he found a well-known freshwater genus (Paludina) among common marine forms.⁷¹

From Copenhagen a rapid journey in Seeland and to Möen introduced him to a number of interesting Sections of the drift, accounts of which were afterwards worked into his books, and showed him at Faxoe and elsewhere limestones overlying the upper chalk, like those at Maestricht in Holland, and at Meudon near Paris. All these limestones possess an exceptional interest, for they contain a mixture of Secondary with Tertiary fossils, and thus help to fill up the wide gap between these two great divisions in Britain and the adjacent parts of Europe. On his return to Copenhagen Lyell was very kindly received by the Crown Prince, who was an ardent naturalist, and allowed him to examine a fine collection of minerals and fossils accumulated by himself.

After crossing the Sound to Malmö, Lyell spent about a fortnight in driving along an inland route through the southern part of Sweden to Norrköping, while a halt at Lund afforded the opportunity of pleasant talks with the professors of the University, and of seeing some formations of which hitherto he had not had much experience. The terms in which he refers to these indirectly proves what strides geology has taken in the last sixty years. "We made an excursion together through a country of greywacke with orthoceratite limestone and schist,⁷² containing a curious zoophyte called graptolite in great abundance, and a few shells." On the journey also he found much to interest a geologist – boulders almost everywhere, some of huge size, lying on the surface or scattered in the sand in one place an outcrop of Cretaceous greensand, full of belemnites, which were popularly regarded as "witches' candles." Then over a picturesque granite region – "a country of rock, fir-wood, and peasants" – till he arrived at Norrköping, and made his way in a steamer down one fjord and up another until he came into the Malar Lake. These last stages introduced him to a kind of scenery of which Scandinavia affords such striking and innumerable examples – the margin of a submerged mountain land. "We entered," he says, "a passage between an endless string of islets and the mainland, the water here smooth as a millpond. We passed swiftly on in deep water close to the rocks, on the barest of which are a few firs in the clefts. These are evidently the summits of submarine mountains." At Stockholm he found plenty to be done. Some of the evidence, which had been brought forward to prove a rising of the land, was obviously weak. For instance, on one of his first visits to a place where the upward movement was said to be comparatively rapid, he found a fine oak-tree, perhaps a couple of centuries old, growing eight feet above high-water mark, and thus indicating either that oak-trees had recently changed their habits or that the change of level had been slow. "In dealing with this question it is necessary," he writes, "to cross-examine both nature and man. The testimony of the former is strong; of the latter, I must say, so weak and contradictory that I require to know the men and find how they got their views." A valuable precaution this, which might be remembered with advantage in days when stay-at-home geologists are far too numerous. If this were done, the paper currency of the science would be considerably reduced in quantity, and there would be a closer correspondence between its real and its nominal value. A little scepticism was certainly justifiable, for one would-be savant stood him out "that a bed of Cardium edule (the common cockle) 100 feet high proves that the fresh water of Lake Malar was once that much higher." Lyell adds nothing to this remark, but his silence is eloquent.

This expedition, however – to Södertelje – gave results yet more striking than marine shells 100 feet above the present level of the Baltic. "What think you," he writes, "of ships in the same formation, nay, a house? It is as true as the Temple of Serapis.⁷³ I do not mean that I discovered all this, but I shall be the first to give a geological account of it. I am in high spirits at the prize." Upsala also, to which he next moved, increased his stores of knowledge and of fossils. "I went to the hill, a hundred feet high, on which the tower stands, to examine marine shells. All of Baltic species. You remember that in the half-hour between the two steamboats at Lübeck, or rather Travemunde, I collected shells by the quay. Not one fossil have I found newer than the chalk in Sweden, that was not in the number of those found living in that half-hour." More localities for shells were visited, erratics were examined, and pilots were questioned closely "about the agency of ice, in which they believe." With their opinion Lyell inclined to agree; at any rate, he was convinced that his observations would "quite overset the débâcle theory," and, as he expected, "bring in ice carriage as the cause." On the coast further north at Oregrund and Gefle, bench-marks had been cut some years previously in order to apply a more exact test to the question of the change in levels. These he visited, and the former seemed to prove "as Galileo said in a different sense, that 'the earth moves.'" The marks near Gefle afforded similar testimony, so that he felt now that the main object of his journey was accomplished, and inserted this pregnant note in his journal: – "I feel now what I was very sensible of when correcting my last edition,⁷⁴ that I was not justified in writing any more until I had done all in my power to ascertain the truth in regard to the 'great northern phenomenon,' as the gradual rise of part of Sweden has been very naturally called. You will see by-and-by how important a point it was, and how materially it will modify my mode of treating the science, and how much it will advance the theory of the agency of existing causes as a key to explain geological phenomena."⁷⁵

But the work at sea-marks was not yet quite ended, and there was besides another classic spot to be visited – Uddevalla, between Lake Werner and the western coast. Here are deposits in which sea-shells are abundant at a height of about two hundred feet above the sea. Nothing but a submergence can account for their presence, for polyzoa and barnacles are found attached to the solid rock. Some of the latter, adhering to the gneiss, were collected by Lyell on this occasion.⁷⁶

Fossil shells (of existing species) were so numerous that, he says, the deposit was worked for making lime, and he compares it with a well-known bed in the Tertiaries of the Paris Basin. The shells, however, at Uddevalla, as he points out, are not of that brackish-water character peculiar to the Baltic, but such as now live in the Northern Ocean.⁷⁷ On reaching the coast he made an expedition by boat, and saw the bench-mark at Gullholmen, and rocks which had emerged from the sea within the memory of people still living. Here, by way of completing his work, he "hired the services of a smith to make a mark at the water's edge: —

C. 18. L.

18. 7. 34."

So he brought his journey in Scandinavia to a close, and by the end of July had reached Kinnordy, where Mrs. Lyell awaited his coming. Then he set to work to prepare a brief sketch of his investigations for the approaching meeting of the British Association in Edinburgh, and a more elaborate paper, to be communicated to the Royal Society in London, in which he set forth the reasons which had convinced him that in Sweden, "both on the Baltic and ocean side, part of that country is really undergoing a gradual and insensibly slow rise." It affects an area measuring about one thousand miles north and south, and is believed to reach a maximum at the North Cape. There it is said, but the statement needs verification, to amount to five feet in a century; at Gefle, ninety miles north of Stockholm, it cannot be more than two or three feet in the same time; while at Stockholm itself it can hardly exceed six inches. Further south, in Scania proper, as at Malmö, Skanör, Trelleborg, and Ystad, the movement is distinctly in an opposite direction.⁷⁸

This paper was afterwards accepted by the Royal Society as the Bakerian lecture for the year. But the preparation of this was not Lyell's only occupation. In October he had begun fossil ichthyology, was attending lectures in chemistry, and "had made some progress," as he writes to Mantell, "in a single volume which two years ago I promised Murray, a purely elementary work for beginners in geology, and which I find more agreeable work than I had expected." So his hands were pretty full. A pleasant surprise came in the closing months of the year, namely the award of one of the Royal Medals by that Society in acknowledgment of the merits of his "Principles of Geology."

In the earlier part of 1835 Lyell accepted the presidency of the Geological Society, an office which, it will be remembered, he had virtually refused a couple of years before, when he was busy with his great book. With this exception, nothing worthy of record appears to have happened in the first six months of the year, but in July Mrs. Lyell and he left England for a journey to France, Germany, and Switzerland. By that date, as he mentions in a letter to a friend, 1,750 copies of the last edition of the "Principles" had been sold, a demand that puts him in good heart as to the future of the book, and proves that his labours on it had not been in vain. But he did not permit himself to be idle. As a letter written to Sedgwick from Paris shows, he was still working away at the classification of the Tertiary deposits; for in this letter he discusses the relation of the coralline and the red, or shelly Crag of Suffolk. Mr. Charlesworth, subsequently well known as a collector, had been obtaining a number of fossil shells from the former deposit, and the character of these suggested that it was distinctly the older of the two, as is now universally admitted. In discussing this question Lyell lays down a principle of classification the soundness of which has been proved by experience, namely, that the age of a Tertiary deposit is to be determined by the proportion of recent species and the relation of these to the forms still living in the neighbouring seas. If, for instance, the recent shells in a formation, amounting to one-half, or even as few as one-third, of the total number can be thus found, the formation will be Pliocene in age, "while the recent shells of the Miocene have a more exotic and tropical form." To this conclusion he had been led, by an examination, with the help of Deshayes, of a typical collection of Crag fossils which he had carried with him to Paris. As to other matters, the leading French geologists were still warring vigorously in defence of deluges, and none of his numerous heresies, he remarks, appears "to have excited so much honest indignation as his recent attempt to convey some of the huge Scandinavian blocks to their present destination by means of ice." He had proved, he reminds Sedgwick, that "some of the great blocks near Upsala must have travelled to their present destination since the Baltic was a brackish water sea, so that those who maintain that there was one, and one only, rush of water, which scattered all the blocks of Sweden and the Alps, must make out this catastrophe to be, as it were, an affair of yesterday." Geology, even at that date, had advanced far enough for this admission to have landed the diluvialists in some awkward dilemmas, to say nothing of the physical difficulties which they would find in accounting for the existence of waves or currents potent enough to bowl the Pierre à bot from the aiguilles round the Trient glacier to the slopes of the Jura, or to fling the erratics of Scandinavia broadcast over the lowlands around the Baltic. This, however, was not the only lost cause over which the French geologists were holding their shield. Lyell goes on to write, with a touch of quiet sarcasm: "As to the elevation crater business, Von Buch, de Beaumont, and Dufresnoy are to write and prove that Somma and Etna are elevation craters, and Von Buch himself has just gone to Auvergne to prove that Mont Dore is one also."

Lyell's special intention in visiting the Alps was to obtain evidence as to the relation of the metamorphic and sedimentary rocks. Geologists of the Wernerian School, with sundry others who hardly went so far as the Freiberg professor, maintained that the crystalline schists, including gneiss, had been produced, often as precipitates, in a primæval ocean, the waters of which were far too hot to allow of the existence of life. At a later time, as the temperature fell, the great masses of slightly altered slates and grits were deposited – the region of "greywacke," the transitional rocks as they were commonly called. These for the most part were unfossiliferous, at any rate in their earliest stages. To this view, of course, the Huttonian dictum, which Lyell sought to establish, was diametrically opposed, viz. that the earth showed no signs of a beginning. Now he had been informed that in the Alps certain slaty rocks contained fossils which indicated an age corresponding generally with the chalk of England, and that in other parts of that chain even crystalline schists could be found interbedded with fossiliferous strata of Secondary age. To settle the former question he intended to visit the famous quarries of Glarus, but was ultimately compelled to leave this for another year, as he took the latter point first in order of time, and the investigation of it involved more work than he had anticipated. In regard to this, the most important sections were to be found on the precipitous northern slopes of the Jungfrau and in the upper part of the Urbach-thal, a lonely glen which descends into the main valley of the Aar at Imhof, above Meyringen. In both these localities gneiss appears to overlie "fossiliferous limestone," and Lyell, after visiting them, returned satisfied that he had seen "alternations of the gneiss with limestone of the lias or something newer in the highest regions of the Alps." That undoubtedly he saw, but he did not suspect that the appearance was illusory. This was not in the least surprising; the Alps were still almost a terra incognita; the processes of "mountain making" as yet were unknown; many statements in common currency as to the passage of sedimentary into crystalline rocks were erroneous and distinctly misleading. Only by degrees was it discovered that this superposition of gneiss or crystalline schist to Secondary rock was due to folding on a scale so gigantic that the older had been doubled over upon the younger rock and the apparent order of succession was the converse of the true one. The intercalation also of the gneiss and the Jurassic limestone was a result of a similar action, but carried, if possible, to an even greater extreme, for here the hard gneiss had been thrust in wedge-like slabs between the softer masses of sedimentary rock, like a paper-knife between the leaves of a book; that is to say, the gneiss and crystalline schists in both cases were vastly more ancient than the fossiliferous limestone. It is only of late years that this startling fact has been established beyond question; and even now there are many geologists who do not appear to recognise how seriously the Huttonian dictum "there is no sign of a beginning" has been shaken by the collapse of this evidence. At the present time the question is in this position; all the attempts to prove crystalline schists to be of the same age as, or younger than, fossiliferous sedimentary rocks either have been complete failures or have proved to be very dubious, while in many cases these schists are demonstrably earlier than the oldest rocks of the district to which a date can be assigned. Hence, though possibly it may turn out that the disciples of Hutton were right, and that, as Lyell thought, a metamorphic rock may be of almost any geological age, his hypothesis not only is unproved, but also the evidence which has been brought forward in its favour has turned out after a strict scrutiny to be exceedingly dubious, if not absolutely contrary. In regard to this question we may feel a little surprise that one difficulty did not occur to Lyell's sceptical mind, namely: what could be the nature and cause of a process of metamorphism which could convert one sediment into a crystalline schist – changed practically past recognition – and leave its neighbour so far unaltered that its characteristic fossils could be readily recognised?

But though he was unable to investigate the question of Secondary or perhaps early Tertiary fossils in the "transition" – like rock of Glarus, his study of the sedimentary deposits of the Bernese Oberland, which had formed a necessary preliminary to the other inquiry, raised some difficulties in his mind as to the origin of slaty cleavage. At a meeting of the Geological Society in the month of March, Professor Sedgwick had read his classic paper⁷⁹ on this subject, in which he established the independence of cleavage and bedding. This paper laid the foundation for the discovery of the true cause of the former structure, though its author was unable, with the information then at his command, to do more than suggest an hypothesis, which afterwards proved to be incorrect. He had shown that both the strike and the dip of cleavage-planes were persistent over large areas, and that while the one might gradually change its direction and the other its angle of inclination, if they were followed far enough, yet this angle usually remained unaltered for considerable distances, and appeared to be quite unaffected by any variation in the slope of the strata. From these observations it followed that the planes of cleavage ought not to be coincident with those of bedding. Lyell, however, writes to tell Sedgwick⁸⁰: —

"I found the cleavage or slaty structure of fine drawing slate in the great quarry of the Niesen, on the east [south] side of the Lake of Thun, quite coincided with the dip of the strata ascertained by alternate beds of greywacke… As it is the best description of drawing slate, and as divisible almost as mica into thin plates, I cannot make out how to distinguish such a structure from any which can be called slaty, and such an attempt would, I fear, involve the subject in great confusion."

The observation was perfectly correct, and many like instances could be found in the Alps; nevertheless, Sedgwick was right in his generalisation, and the two structures are perfectly independent, though the difficulty raised by Lyell did not disappear till the true cause of slaty cleavage was recognised – viz. that it is a result of pressure. Thus, in a region like the Alps, where the strata often have been so completely folded as to be bent, so to say, back to back, the planes of cleavage, which are produced when the rocks can no longer yield to the pressure by bending, necessarily coincide with those of bedding. Still, even in these cases, if careful search be made in the vicinity, some minor flexure generally betrays the secret, and exhibits the cleavage structure cutting across that of bedding.

The next year, 1836, flowed on, like the last, quietly and uneventfully; a fifth edition of the "Principles" was passing through the press; the "Elements of Geology" was making progress, though slowly; and Lyell's duties as President of the Geological Society, which involved the delivery of an address in the month of February and the preparation of another one for the same season in the following year, occupied a good deal of his time. The summer was spent in a long visit to his parents at Kinnordy, after which he and Mrs. Lyell made some stay in the Isle of Arran before they returned to London. The latter seemingly had been rather out of health, and this may have been the reason why a longer journey was not undertaken, but she must have found the Scotch air a complete restorative, for after her return to London in the autumn Lyell writes to his father that "everyone is much struck with the improvement in Mary's health and appearance."

But one letter, of the few which have been preserved from those written in 1836, possesses a special interest, for it expresses his ideas, at this epoch, in regard to the question of the origin of species, and indicates his freedom from prejudice and the openness of his mind. It is addressed to Sir John Herschel, then engaged in his memorable investigations at the Cape of Good Hope, who had favoured him with some valuable comments and criticisms on the Principles of Geology, and in the course of these had corrected a mistake which Lyell had made in regard to a rather difficult physical question. In referring to this, the latter remarks that the clearness of the mathematical reasoning (to quote his words) "made me regret that I had not given some of the years which I devoted to Greek plays and Aristotle at Oxford, and afterwards to law and other desultory pursuits, to mathematics." Doubtless there is hardly any better foundation for geology than a course of mathematics; at the same time, classical studies did much to give Lyell his lucidity and elegance of style, and thus to ensure the success of the "Principles of Geology."