The Valley of Aosta is famous for its bouquetins, and infamous for its cretins. The bouquetin, steinbock, or ibex, was formerly widely distributed throughout the Alps. It is now confined almost entirely to a small district on the south of the Valley of Aosta, and fears have been repeatedly expressed in late years that it will speedily become extinct.

The most sanguine person does not imagine that cretinism will be eradicated for many generations. It is widely spread throughout the Alps; it is by no means peculiar to the Valley of Aosta; but nowhere does it thrust itself more frequently upon the attention of the traveller, and in no valley where “every prospect pleases,” is one so often and so painfully reminded that “only man is vile.”

It seems premature to fear that the bouquetin will soon become extinct. It is not easy to take a census of them, for, although they have local habitations, it is extremely difficult to find them at home. Yet there is good reason to believe that there are at least several hundreds still roaming over the mountains in the neighbourhood of the valleys of Grisanche, Rhèmes, Savaranche, and Cogne.

It would be a pity if it were otherwise. They appeal to our sympathies as the remnants of a diminishing race. No mountaineer or athletic person could witness without sorrow the extinction of an animal possessing such noble qualities;⁠—which a few months after birth can jump over a man’s head at a bound, without taking a run; which passes its whole life in a constant fight for existence; which has such a keen appreciation of the beauties of nature, and such disregard of pain that it will “stand for hours like a statue, in the midst of the bitterest storm, until the tips of its ears are frozen”! and which, when its last hour arrives, “climbs to the highest mountain-peaks, hangs on a rock with its horns, twists itself round and round upon them until they are worn off, and then falls down and expires”!!232 Even Tschudi himself calls this story wonderful.

Forty-five keepers, selected from the most able chasseurs of the district, guard its haunts. Their task is not a light one, although they are, naturally, acquainted with those who are most likely to attempt poaching. If they were withdrawn, it would not be long before the ibex would be an extinct wild animal, so far as the Alps are concerned. The passion for killing something, and the present value of the beast itself, would soon lead to its extermination. For as meat alone the bouquetin is valuable; the gross weight of one that is full grown ranging from 160 to 200 lbs.; while its skin and horns are worth £10 and upwards, according to condition and dimensions.

In spite of the keepers, and of the severe penalties which may be inflicted for killing a bouquetin, poaching occurs constantly. Knowing that this was the case, I inquired at Aosta, upon one of my last visits, if any skins or horns were for sale, and in ten minutes was taken into a garret where the remains of a splendid beast were concealed⁠—a magnificent male, presumed to be more than twenty years old, as its massive horns had twenty-two more or less strongly marked knobby rings. The extreme length of the skin, from the tip of the nose to the end of the tail, was 1 metre 69 centimetres (about 5 feet 7 inches), and from the ground to the top of its back had been, apparently, about 77 centimetres. It is rare to meet with a bouquetin of these dimensions, and the owner of this skin might have been visited with several years’ imprisonment if it had been known that it was in his possession.

The chase of the bouquetin is a sport fit for a king, and the Kings of Italy, for whom it is reserved, have been too good sportsmen to slaughter indiscriminately an animal which is an ornament to their dominions. In 1868, his Majesty Victor-Emmanuel presented a fine specimen to the Italian Alpine Club. The members banqueted upon its flesh, and had the skin stuffed, and set up in their rooms at Aosta. From this specimen the accompanying engraving has been made.

It is a full-grown male, about twelve years old, and if it stood upright would measure three feet three and a half inches from the ground to the base of its horns. Its extreme length is four feet seven inches. Its horns have eleven well-marked rings, besides one or two faintly-marked ones, and are (measured round their curvature) 54½ centimetres in length. The horns of the specimen referred to earlier (measured in the same way) had a length of only 53½ centimetres, although they were ornamented with nearly double the number of rings, and were presumably of double the age of the former.233

The keepers, and the chasseurs of this district, not only say that the rings upon the horns of the ibex tell its age (each one reckoning as a year), but that the half-developed ones, which sometimes are very feebly marked indeed, show that the animal has suffered from hunger during the winter. Naturalists are sceptical upon this point; but inasmuch as they offer no better reason against the reputed fact than the natives do in its favour (one saying that it is not so, and the other saying that it is so), we may, perhaps, be permitted to consider it an open question. I can only say that if the faintly-marked rings do denote years of famine, the times for the bouquetin are very hard indeed; since, in most of the horns which I have seen, the lesser rings have been numerous, and sometimes more plentiful than the prominent ones.

The Chef of the keepers (who judged by the above-mentioned indications) told me that the ibex not unfrequently arrives at the age of thirty years, and sometimes to forty or forty-five. He said, too, that it is not fond of traversing steep snow, and in descending a couloir that is filled with it, will zigzag down, by springing from one side to the other, in leaps of fifty feet at a time! Jean Tairraz,234 the worthy landlord of the Hôtel du Mont Blanc at Aosta (who had opportunities of observing the animal closely), assured me that at the age of four or five months it can easily clear a height of nine or ten feet at a bound!235 Long life to the bouquetin! but down with the cretin!

The extreme form of idiocy which is called cretinism236 is so highly developed in the Valley of Aosta, and the natives are so familiarised with it, that they are almost indignant when the surprised traveller remarks its frequency. One is continually reminded by them that the disease is not peculiar to the valley, and that there are cretins elsewhere. It is true that this terrible scourge is widespread throughout the Alps and over the world, and that there are places where the proportion of cretins to population is, or has been, even greater than in the Valley of Aosta; but one seldom sees a valley so fertile and so charming, one which⁠—apart from cretinism⁠—leaves so agreeable an impression upon the wayfarer, where equal numbers of individuals are reduced to a condition which any respectable ape might despise.

The whole subject of cretinism is surrounded with difficulty. The number of those who are afflicted by it is unknown; its cure is doubtful; and its origin is mysterious. It has puzzled acute observers, and every general statement in regard to it must be fenced by qualifications.

It is tolerably certain, however, that the centre of its distribution in the Valley of Aosta is about the centre of the valley. The city of Aosta itself may be regarded as its headquarters. It is there, and in the neighbouring towns of Gignod, Villeneuve, St. Vincent, and Verrex, and in the villages and upon the high-road between those places, that these distorted, mindless beings commonly excite one’s disgust by their hideous, loathsome, and uncouth appearance, by their obscene gestures, and by their senseless gabbling. The accompanying portrait of one is by no means overdrawn⁠—some are too frightful for representation.

How can we account for this particular intensity towards the middle of the valley? Why is it that cretins become more and more numerous after Ivrea is passed, attain their highest ratio and lowest degradation at or about the chief town of the valley, and then diminish in numbers as its upper termination is approached? This maximum of intensity must certainly point to a cause, or to a combination of causes, operating about Aosta, which are less powerful at the two extremities of the valley; and if the reason for it could be determined, the springs of cretinism might be exposed.

The disease would be even more puzzling than it is if it were confined to this single locality, and the inquirer were to find not merely that it was almost unknown upon the plains to the east and in the districts to the west, but that the valleys radiating north and south from the main valley were practically unaffected by it. For it is a remarkable circumstance, which has attracted the notice of all who have paid attention to cretinism, that the natives of the tributary valleys are almost free from the malady;⁠—that people of the same race, speaking the same language, breathing the same air, eating the same food, and living the same life, enjoy almost entire immunity from it, while, at the distance of a very few miles, thousands of others are completely in its power.

A parallel case is found, however, on the other side of the Pennine Alps. The Rhône Valley is also disfigured by cretinism, and in it, too, the extremities of the valley are slightly affected compared with the intermediate districts⁠—particularly those between Brieg and St. Maurice.237 This second example strengthens the opinion that the great development of cretinism in the middle of the Valley of Aosta is not the result of accidental circumstances.

It was formerly supposed that cretinism arose from the habitual drinking of snow and glacier water. De Saussure opposed to this conjecture the facts, that the disease was entirely unknown precisely in those places where the inhabitants were most dependent upon these kinds of water, and that it was most common where such was not the case;⁠—that the high valleys were untainted, while the low ones were infected.238 The notion seems to have proceeded from cretins being confounded with persons who were merely goitred; or, at least, from the supposition that goitre was an incipient stage of cretinism.

Goitre, it is now well ascertained, is induced by the use of chemically impure water, and especially hard water; and the investigations of various observers have discovered that goitre has an intimate connection with certain geological formations.239 In harmony with these facts, it is found that infants are seldom born with goitres, but that they develop as the child grows up; that they will sometimes appear and disappear from mere change of locality;240 and that it is possible to produce them intentionally.

It is not so certain that the causes which produce goitre should be regarded as causes of the production or maintenance of cretinism. It is true that cretins are very generally goitrous, but it is also true that there are tens of thousands of goitrous persons who are entirely free from all traces of cretinism. Not only so, but that there are districts in the Alps, and outside of them (even in our own country), where goitre is not rare, but where the cretin is unknown. Still, regarding the evil state of body which leads to goitre as being, possibly, in alliance with cretinism, it will not be irrelevant to give the former disease a little more attention before continuing the consideration of the main subject.

In this country the possession of a goitre is considered a misfortune rather than otherwise, and individuals who are afflicted with these appendages attempt to conceal their shame. In the Alps it is quite the reverse. In France, Italy, and Switzerland, it is an advantage to be goitred, as it secures exemption from military service. A goitre is a thing to be prized, exhibited, preserved⁠—it is worth so much hard cash; and it is an unquestionable fact that the perpetuation of the great goitrous family is assisted by this very circumstance.

When Savoy was annexed to France, the administration took stock of the resources of its new territory, and soon discovered that, although the acres were many, the conscripts would be few. The government bestirred itself to amend this state of affairs, and after arriving at the conclusion that goitre was produced by drinking bad water (and that its production was promoted by sottish and bestial habits), took measures to cleanse the villages, to analyse the waters (in order to point out those which should not be drunk), and to give to children who came to school lozenges containing small doses of iodine. It is said that out of 5,000 goitrous children who were so treated in the course of eight years, 2,000 were cured, and the condition of 2,000 others was improved; and that the number of cures would have been greater if the parents “had not opposed the care of the government, in order to preserve the privilege of exemption from military service.”241 These benighted creatures refused the Marshal’s baton and preferred their “wallets of flesh!”242

No wonder that the Préfet for Haute-Savoie proposes that goitrous persons shall no longer be privileged. Let him go farther, and obtain a decree that all of them capable of bearing arms shall be immediately drafted into the army. Let them be formed into regiments by themselves, brigaded together, and commanded by cretins. Think what esprit de corps they would have! Who could stand against them? Who would understand their tactics? He would save his iodine, and would render an act of justice to the non-goitred population. The subject is worthy of serious attention. If goitre is really an ally of cretinism, the sooner it is eradicated the better.243

De Saussure put forward heat and stagnation of air as causes of cretinism in the place of badness of water. But this was only giving up one unsatisfactory explanation for another equally untenable; and since there are places far hotter and with pernicious atmospheres where the disease is unknown, while, on the other hand, there are situations in which it is common where the heat is not excessive, and which enjoy a freely circulating atmosphere, his assumption may be set aside as insufficient to account for the cretinism of the Valley of Aosta.244 And in regard to its particular case, it may be questioned whether there is anything more than an imaginary stagnation of air. For my own part, I attribute the oppression which strangers say they feel, in the middle of the valley, not to stagnation of air but to absence of shadow, in consequence of the valley’s course being east to west; and believe, that if the force of the wind were observed and estimated according to the methods in common use, it would be found that there is no deficiency of motion in the air throughout the entire year. Several towns and villages, moreover, where cretins are most numerous, are placed at the entrances of valleys and upon elevated slopes, with abundant natural facilities for drainage⁠—free from malaria, which has been suggested as accounting for the cretinism of the Rhône Valley.

Others have imagined that intemperance,245 poor living, foul habits, and personal uncleanliness, sow the seeds of cretinism, and this opinion is entitled to consideration. Intemperance of divers kinds is fruitful in the production of insanity,246 and herding together in filthy dwellings, with little or no ventilation, may possibly deteriorate physique, as much as extreme indulgence may the mind. These ideas are popularly entertained because cretins are more numerous amongst the lower orders than in the well-to-do classes. Yet they must, each and all, be regarded as inadequate to account for the disease, still less to explain its excess in the centre of the valley. For in these respects there is little or no distinction between it, the two extremities, and the neighbouring districts.

A conjecture remains to be considered regarding the origin of cretinism, which is floating in the minds of many persons (although it is seldom expressed), which carries with it an air of probability that is wanting in the other explanations, and which is supported by admitted facts.

The fertility of the Valley of Aosta is proverbial. It is covered with vineyards and cornfields; flocks and herds abound in it; and its mineral resources are great. There is enough and to spare both for man and beast. There are poor in the valley, as there are everywhere, but life is so far easy that they are not driven to seek for subsistence in other places, and remain from generation to generation rooted to their native soil. The large numbers of persons who are found in this valley having the same surnames is a proof of the well-known fact that there is little or no emigration from the valley, and that there is an indefinite amount of intermarriage between the natives. It is conjectured that the continuance of these conditions through a long period has rendered the population more or less consanguineous, and that we see in cretinism an example, upon a large scale, of the evil effects of alliances of kindred.

This explanation commends itself by reason of its general applicability to cretinism. The disease is commonly found in valleys, on islands,247 or in other circumscribed areas, in which circulation is restricted, or the inhabitants are nonmigratory; and it is rare on plains, where communications are free. It will at once be asked, “Why, then, are not the tributary valleys of the Valley of Aosta full of cretins?” The answer is, that these lateral valleys are comparatively sterile, and are unable to support their population from their internal resources. Large numbers annually leave, and do not return⁠—some come back, having formed alliances elsewhere. There is a constant circulation and introduction of new blood. I am not aware that there are returns to show the extent to which this goes on, but the fact is well known.248

This conjecture seems to explain, better than the other guesses, why it is that cretinism has so strong a hold upon the lower classes, while it leaves the upper ones almost untouched; for the former are most likely to intermarry with people of their own district, whilst the latter are under no sort of compulsion in this respect. It gives a clue, too, to the reason of the particular intensity in the centre of the valley. The inhabitants of the lower extremity communicate and mix with the untainted dwellers on the plains, whilst the conditions at the upper extremity approximate to those of the lateral valleys. Before this explanation will be generally received, a closer connection will have to be established between the assumed cause and the presumed effect.249 Accepting it, nevertheless, as a possible one, let us now consider what prospect there is of checking the progress of the disease.

It is, of course, impossible to change the habits of the natives of the Valley of Aosta suddenly, and it would, probably, be very difficult to cause any large amount of emigration or immigration. In the present condition of Italian finances there is very small chance of any measure of the sort being undertaken if it would involve a considerable expenditure. The opening of the railway from Ivrea to Aosta may possibly bring about, in a natural way, more movement than could be promoted by any legislation, and by this means the happiest effects may be produced.250

There is little hope of practical results from attempts to cure cretins. Once a cretin, you are always one.251 The experiments of the late Dr. Guggenbühl demonstrated that some half-cretins may even become useful members of society, if they are taken in hand early in life; but they did not show that the nature of the true or complete cretin could be altered.252 He essayed to modify some of the mildest forms of cretinism, but did not strike at the root of the evil. If fifty Guggenbühls were at work in the single Valley of Aosta, they would take several generations to produce an appreciable effect, and they would never extirpate the disease so long as its sources were unassailed.

Nor will the house which has been built at Aosta253 to contain 200 cretin beggars do much, unless the inmates are restrained from perpetuating their own degradation. Even the lowest types of cretins may be procreative, and it is said that the unlimited liberty which is allowed to them has caused infinite mischief. A large proportion of the cretins who will be born in the next generation will undoubtedly be offspring of cretin parents. It is strange that self-interest does not lead the natives of Aosta to place their cretins under such restrictions as would prevent their illicit intercourse; and it is still more surprising to find the Catholic Church actually legalising their marriage. There is something horribly grotesque in the idea of solemnising the union of a brace of idiots; and since it is well known that the disease is hereditary, and develops in successive generations, the fact that such marriages are sanctioned is scandalous and infamous.254

The supply, therefore, is kept up from two sources. The first contingent is derived from apparently healthy parents; the second, by inheritance from diseased persons. The origin of the first is obscure; and before its quota can be cut off, or even diminished, the mystery which envelops it must be dissipated. The remedy for the second is obvious, and is in the hands of the authorities⁠—particularly in those of the clergy. Marriage must be prohibited to all who are affected; the most extreme cases must be placed under restraint; and cretins whose origin is illegitimate must be subject to disabilities. Nothing short of the adoption of these measures will meet the case. Useless it will be, so long as the primary sources of the disease are untouched, to build hospitals, to cleanse dwellings, to widen streets, or to attempt small ameliorations of the social circumstances of the natives. All of these things are good enough in themselves, but they are wholly impotent to effect a radical change.

No satisfactory conclusion will be arrived at regarding the origin of cretinism until the pedigrees of a large number of examples have been traced. The numerical test is the only one which is likely to discover the reality. The necessary inquiries are beyond the powers of private persons, and their pursuit will be found sufficiently difficult by official investigators. Great reluctance will be exhibited to disclose the information which should be sought, and the common cry will certainly be raised, that such scrutiny is without general advantage, and is painful to private feelings. But, in matters which affect mankind in general, individual feelings must always be subordinated to the public interest; and if the truth is to be arrived at in regard to cretinism, the protests of the ignorant will have to be overridden.

Hitherto, those who have written upon the disease have confined themselves, almost exclusively, to guessing at its origin; and accurate data, from which sound deductions can be made, are, I believe, entirely wanting.255 We, however, are not in a position to taunt others with neglect of inquiry. Some years ago the House of Commons rejected, by a considerable majority, a proposition that was designed to throw light upon the causes of idiocy; and the opponents of the words which it was sought to introduce, although strictly parliamentary in their arguments and language, afforded a deplorable proof that cretinism is not unknown in our own country.256

Cretinism is the least agreeable feature of the Valley of Aosta, but it is, at the same time, one of the most striking. It has been touched upon for the sake of its human interest, and on account of those unhappy beings who⁠—punished by the errors of their fathers⁠—are powerless to help themselves;⁠—the first sight of whom produced such an impression upon the most earnest of all Alpine writers, that he declared, in a twice-repeated expression, its recollection would never be effaced from his memory.257

At some very remote period the Valley of Aosta was occupied by a vast glacier, which flowed down its entire length from Mont Blanc to the plain of Piedmont, remained stationary, or nearly so, at its mouth for many centuries, and deposited there enormous masses of debris. The length of this glacier exceeded 80 miles, and it drained a basin 25 to 35 miles across, bounded by the highest mountains in the Alps. It did not fill this basin. Neither the main stream nor its tributaries completely covered up the valleys down which they flowed. The great peaks still rose several thousand feet above the glaciers, and then, as now, shattered by sun and frost, poured down their showers of rocks and stones, in witness of which there are the immense piles of angular fragments that constitute the moraines of Ivrea.258 The wine which is drunk in that town is produced from soil that was borne by this great glacier from the slopes of Monte Rosa; and boulders from Mont Blanc are spread over the country between that town and the Po, supplying excellent materials for building purposes, which were known to the Romans, who employed them in some of their erections at Santhia.259

The moraines around Ivrea are of extraordinary dimensions. That which was the lateral moraine of the left bank of the glacier is about thirteen miles long, and, in some places, rises to a height of 2,130 feet above the floor of the valley! Professor Martins termed it “la plus elevée, la plus régulière, et la mieux caractérisée des Alpes.”260 It is locally called “la Serra.” The lateral moraine of the right bank also rises to a height of 1,000 feet, and would be deemed enormous but for the proximity of its greater comrade; while the terminal moraines cover something like twenty square miles of country.

The erratic nature of the materials of these great rubbish-heaps was distinctly pointed out by De Saussure (Voyages, §§ 974⁠–⁠978); their true origin was subsequently indicated by Messrs. Studer (1844) and Guyot (1847); and the excellent account of them which has since been published by Professors Martins and Gastaldi leaves nothing to be desired either in accuracy or completeness.261 It is not my purpose, therefore, to enter into a description of them, but only to discuss some considerations arising out of the facts which have been already mentioned.

It has been proved beyond doubt that these gigantic mounds around Ivrea are actually the moraines of a glacier (now extinct) which occupied the Valley of Aosta; and it is indisputable that there are boulders from Mont Blanc amongst them. The former facts certify that the glacier was of enormous size, and the latter that it must have existed for a prodigious length of time.

The height of “la Serra” indicates the depth of the glacier. It does not fix the depth absolutely, inasmuch as the crest of the moraine must have been degraded during the thousands of years which have elapsed since the retreat of the ice; and, further, it is possible that some portions of the surface of the glacier may have been considerably elevated above the moraine when the ice was at its maximum thickness. Anyhow, at the mouth of the Valley of Aosta, the thickness of the glacier must have been at least 2,000 feet, and its width, at that part, five miles and a quarter.

The boulders from Mont Blanc, upon the plain below Ivrea, assure us that the glacier which transported them existed for a prodigious length of time. Their present distance from the cliffs from which they were derived is about 420,000 feet, and if we assume that they travelled at the rate of 400 feet per annum, their journey must have occupied them no less than 1,055 years! In all probability they did not travel so fast. But even if they were to be credited with a quicker rate of motion, the length of time which their journey must have taken will be sufficient for my purposes.262

The space of 1,055 years, however, by no means represents the duration of the life of the glacier of Aosta. It may have existed for immense periods both anterior and posterior to the journeys of the Mont Blanc boulders. The frontal terminal moraines, which stretch from Caluso to Viverone (a distance of more than ten miles), are evidence that the snout of the glacier remained stationary, or nearly so, for a length of time which must at least be estimated by centuries, and probably extended over thousands of years. These moraines constitute important chains of hills whose bases are several miles across, and which attain a height of more than a thousand feet; and, as they were formed by the gradual and slow spreading out of the medial and lateral moraines, it is evident that they were not built up in a day.

Moreover, when the glacier of Aosta shrank away from Ivrea, its retrogression may have been comparatively rapid, or it may have been conducted with extreme deliberation. But, under any circumstances, the extinction of such a tremendous body of ice must have extended over many years, and for a portion of that time a large part of the mass must have been advancing down the valley, although the snout of the glacier was retreating, and although the entire mass was diminishing in volume. If the time is considered which was consumed during this phase of its life, and the time which elapsed during its prolonged sojourn at Ivrea, and the time which passed before it attained its maximum dimensions, it must be conceded that the period of 1,055 years was, in all probability, only a small portion of the epoch during which the Valley of Aosta sustained the grinding of this enormous mass of ice.

Let us confine ourselves to certainties. Here, then, was a glacier which flowed down the Valley of Aosta for more than a thousand years, having a thickness of 2,000 feet,263 a width of several miles, and a length of eighty miles. The existing glaciers of the Alps do not approach these dimensions, and even in the period when the ice-streams of Europe had so great an extension there were very few which surpassed them. Still fewer, perhaps, existed for so long time, and there are probably only one or two⁠—such as the ancient glacier of the Rhône⁠—which have received as much attention and have been as carefully studied. For these reasons it seems to me to be more advantageous to refer to it than to instances which are less known and more open to doubt; and I select it, on account of these reasons, as a valley that should afford strong testimony in support of the theories which assert that the valleys and many of the lake-basins of the Alps have been excavated by glaciers.

The latter of these two theories was communicated to the Geological Society, by Professor Ramsay, on March 5, 1862.264 It received much attention, and excited much criticism, but Professor Ramsay replied to few of his critics, excepting Sir Roderick Murchison and Sir Charles Lyell. In answer to the objections which were raised against the reception of his theory by these distinguished geologists, he published two papers in the Philosophical Magazine;265 and, in endeavouring to present my reader with a résumé of the Professor’s views, I shall draw from these papers as freely as from his original memoir, for they afford amplification and elucidation of his argument.266

Professor Ramsay said, in opening his case, “There is no point in physical geography more difficult to account for than the origin of most lakes. When thought about at all, it is easy to see that lakes are the result of the formation of hollows, a great proportion of which are true rock-basins, that is to say, in hollows entirely surrounded by solid rocks, the waters not being retained by loose detritus.”267 It is in reference to such ones alone that his theory was propounded. He then went on to state, in especial reference to lakes of this class in the Alps⁠—

§ 1. “That the theory of an area of special subsidence for each lake is untenable.

§ 2. That none of them lie in lines of gaping fracture (rents and fissures).

§ 3. That none of them occupy simple synclinal basins formed by the mere disturbance of the strata after the close of the Miocene epoch.”268

And he therefore argued that they must have been produced by erosion; but

§ 4. They do not lie in hollows of common watery erosion, nor can they be effects of marine denudation.

He consequently concluded, “If we have disposed of these hypotheses for the formation of such hollows, what is left?

§ 5. The only remaining agent is the denuding power of ice.”269

He then proved that, in the Alps and elsewhere,

§ 6. “Each of the lakes lies in an area once covered by a vast glacier.”270

And went on to reason⁠—

§ 7. “If a glacier can round, polish, and cover with striations the rocks over which it passes⁠—if, flowing from its caverns, it can charge rivers thickly with the finest mud, then it can wear away its rocky floor and sides.”271

§ 8. He assumed that glaciers are competent to produce lake-basins, and that they have done so by scooping out softer parts of the country, leaving hollows surrounded by a framework of harder rocks; “but perhaps more generally they (the rock-basins) were formed by the greater thickness and weight, and consequently proportionally greater grinding pressure of glacier-ice in particular areas,”272 “the situations of which may have been determined by accidental circumstances, the clue to which is lost, from our inability perfectly to reconstruct the original forms of the glaciers.”273

The particular manner in which he supposed the great lake-basins of the Alps were formed was as follows:⁠—

§ 9. “It will be evident that when the general inclination of a valley was comparatively steep, a glacier could have had no opportunity of cutting for itself any special basin-shaped hollows. Its course, with a difference, is like that of a torrent. But in a flat-bottomed part of a valley, or in a comparative plain that lies at the base of a mountain range, the case is not the same. For instance, to take an extreme case, if a glacier tumble over a slope of 45°, no one would dream of the ice-flow producing any special effect, except that in the long run, the upper edge of the rock that forms the cataract being worn away, its average angle would be lowered. And so of minor slopes; if the ice flowing fast (for a glacier) rendered the rocky surface underneath unequal, such inequalities could not become great and permanent; for the rapidly-flowing ice would attack the projecting parts with greater power and effect than the minor hollows, and so preserve an approximate uniformity, or an average angle of moderate inclination. But when a monstrous glacier descended into a comparative plain, or into a low flat valley, the case was different. There, to use homely phrases, the ice had time to select soft places for excavation, and there, if from the confluence of large glaciers, or for other reasons, the downward pressure of the ice was of extra amount, the excavating effect, I contend, must have been unusually great in special areas, and have resulted in the formation of rockbound hollows.”274

He accounted for the deep parts of the lakes by supposing that⁠—

§ 10. “The grinding action lasted after a glacier had retired above the position of the present lake-barrier, so that the waste of the rocky floor being long continued, by degrees the glacier wore out a depression deeper and deeper, till, on its final retirement, the space once occupied by ice became filled with the water drainage of the valley.”275

The shallowness at their mouths was thus explained:⁠—

§ 11. As the glaciers “progressed and melted, the ice must have been thinner, and must have exercised less erosive power than where it was thick, whence the gradual slope of the bottom of these lakes towards their outflows.”276

§ 12. “Therefore I have been forced to the conclusion, from a critical examination of many of the lakes in and around the Alps, that their basins were scooped out by the great glaciers of the glacial period.”277

The astonishment which Professor Ramsay’s theory created had not subsided when Professor Tyndall brought forward opinions of an even bolder character,278 and avowed his belief that the valleys of the Alps had been (entirely?) excavated by glaciers! His summing up was as follows:⁠—

“That such an agent was competent to plough out the Alpine valleys cannot, I think, be doubted; while the fact that during the ages which have elapsed since its disappearance the ordinary denuding action of the atmosphere has been unable, in most cases, to obliterate even the superficial traces of the glaciers, suggests the incompetence of that action to produce the same effect. That the glaciers have been the real excavators seems to me far more probable than the supposition that they merely filled valleys which had been previously formed by water denudation. Indeed the choice lies between these two suppositions: shall we assume that glaciers filled valleys which were previously formed by what would undoubtedly be a weaker agent? or shall we conclude that they have been the excavators which have furrowed the uplifted land with the valleys which now intersect it? I do not hesitate to accept the latter view.”

—⁠Phil. Mag., Sept. 1862, p. 172.

Except for the character of the magazine in which Dr. Tyndall’s paper appeared, it might have been supposed that he was poking fun at his readers and at Professor Ramsay. For although to some persons he might have seemed to be supporting the views of the Professor, he was, in reality, advancing opinions which were directly opposed to them. Professor Ramsay promptly repudiated this doubtful extension of his theory. Indeed, he could hardly do otherwise, after having spoken of “the well-ascertained fact, that previous to the Tertiary glacial epoch, most of the grander contours of hill and valley were in Britain (and elsewhere in Europe and America), nearly the same as now.”279 He now repeated the same statement in slightly different words. “The evidence is imperfect; but such as it is, it gives much more than a hint that the large valleys were in their main features approximately as deep as now, before they were filled with ice;”280 and, further, he produced in evidence a potent reason for declining to believe that the Valley of Aosta had been excavated by glaciers. This latter passage will presently be quoted at length, on account of its importance.281

For a time Dr. Tyndall made no sign in reply, but, in October 1864, he communicated another paper to the Philosophical Magazine, in which he modified his views to a certain extent (and made the important admission that it was perhaps impossible to say whether water or ice had produced the greatest amount of erosion), although upon the whole he adhered to his former assertions. This paper contained one remarkable passage; remarkable, because it partly showed the workings of its author’s mind, and because it was, apparently, intended to controvert Professor Ramsay’s theory. It was as follows:⁠—

“On the higher slopes and plateaus⁠—in the region of cols⁠—the power (of glaciers) is not fully developed; but lower down tributaries unite, erosion is carried on with increased vigour, and the excavation gradually reaches a maximum. Lower still the elevations diminish and the slopes become more gentle; the cutting power gradually relaxes, and finally the eroding agent quits the mountains altogether, and the grand effects which it produced in the earlier portions of its course entirely disappear.”282

—⁠Phil. Mag., Oct. 1864, p. 264.

That is to say, precisely in the situations where Professor Ramsay required glaciers to produce the greatest effects, Dr. Tyndall asserted they produced none whatever! Professor Ramsay did not allow much time to elapse before he contradicted these statements categorically.

“Every physicist,” said he, “knows that when such a body as glacier-ice descends a slope, the direct vertical pressure of the ice will be proportional to its thickness and weight and the angle of the slope over which it flows. If the angle be 5°, the weight and erosive power of a given thickness of ice will be so much, if 10° so much less, if 20° less still, till at length, if we may imagine the fall to be over a vertical wall of rock, the pressure against the wall (except accidentally) will be nil. But when the same vast body of ice has reached the plain, then motion and erosion would cease, were it not for pressure from behind (excepting what little motion forward and sideways might be due to its own weight). This pressure, however, must have been constant as long as supplies of snow fell on the mountains, and therefore the inert mass in the plain was constantly urged onwards; and because of its vertical pressure its direct erosive power would necessarily be proportional to its thickness, and greater than when it lay on a slope; for it would grate across the rocks, as it were, unwillingly and by compulsion, instead of finding its way onwards more or less by virtue of gravity. Indeed the idea is forced on the mind, that the sluggish ice would have a tendency to heap itself up just outside the mouth of the valley, and there attain an unusual thickness, thus exercising, after its descent, an extra erosive power.”283

—⁠Phil. Mag., April 1865, p. 287.

Professor Tyndall does not appear to have found the reply convincing. He is reported to have said at the Birmingham meeting of the British Association in 1865, “that he was convinced that the glaciers of the Alps were competent to scoop out the valleys of the Alps,”284 and I am unaware that his opinions have undergone any alteration since that time. In 1869 he gave a hard side-blow to Professor Ramsay, in Macmillan’s Magazine, by proving that some existing Alpine glaciers exercise little or no erosion upon their beds near and at their terminations (snouts), because at such places they are almost stationary.285

It is impossible to criticise these two theories at the same moment. Both of them agree in attributing enormous powers of excavation to glaciers, but they disagree totally and completely as to the modus operandi by which the effects were produced. They differ even in their general conclusions. One asserts that the greatest effects were produced upon the plains, and that very little was done amongst the mountains; whilst the other declares that the mountains owe their actual forms to the carving of glaciers, and that the plains did not suffer at all! There is no wonder that the unenlightened public inquire, “Who shall decide between the disagreements of these Doctors?” But it is surprising to find some persons still accept as gospel truth the contradictory dicta of these eminent men, and speak and writ as if it were established that lake-basins and mountain-valleys have been excavated by glaciers.

It is not requisite to decide between all the differences contained in these two theories, in order to arrive at a tolerably correct judgment upon the general conclusions. Professor Ramsay, for example, attributes the production of the greatest effects to the weight of glaciers. Professor Tyndall, on the other hand, assigns most power to the motion. I shall ignore these points, because I have no data from which to arrive at a satisfactory decision, and because it is not necessary for them to be mixed up with a discussion of the question, Were the valleys of the Alps excavated by glaciers? For the consideration of this subject, let us now return to the Valley of Aosta.

The town of Ivrea is placed at the mouth of, though not actually within the valley, and several miles of flat, dusty road have to be traversed before it is entered. Upon this portion of the country civilisation is doing its best to efface the traces of the glacial period. Cultivation of the soil disturbs all deposits, and the hammers of the masons destroy the erratics. After quitting Ivrea, almost the first object of interest is the castle of Montalto, perched on a commanding crag, nearly in the centre of the valley. Thence, from Settimo Vittone up to the foot of the existing glaciers of the range of Mont Blanc, there are traces of glacier-action upon each hand. The road need not be quitted to seek for them;⁠—they are everywhere. I refer especially to the rocks in situ. The rock-forms called roches moutonnées are universally distributed, and it is needless, at the present moment, to point to any in particular. Although of varying degrees of resistancy, they have, upon the whole, stood the weathering remarkably well of the thousands of years which have elapsed since the glacier covered them. The floor of the valley, generally speaking, has not been lowered since that time, by the combined agencies of sun, frost, and water, to any appreciable extent. The forms which the roches moutonnées present today, are the forms which they presented, perhaps, ten thousand years ago. Many of those which are freely exposed to the atmosphere retain a high polish and fine striations. If the soil were to be removed that covers the flatter portions of the valley, we should doubtless find higher polish, and still finer striations. Those which are visible remain so perfect that it is certain weathering has done exceedingly little to alter their contours, and we may argue regarding them as if their icy covering had been but just removed. It seems to me, it may be demonstrated from the very contours of these glaciated rocks, that the valley was not excavated by glaciers, and indeed, that it was eroded by glaciers only to a very limited extent.

For the forms which are called moutonnées preponderate very largely. The rocks which I have ventured to term roches nivelées, are comparatively rare,286 although they are sufficiently numerous to show that the valley was subjected to severe grinding for a great length of time. They are found upon the floor of the valley, or in places where it narrows, or upon the lower sides of little ravines (now watercourses) which the glacier had to cross, into which it was forced down when in the act of crossing, and out of which it escaped by mounting the opposite bank. In brief, they are found precisely where they should be found. In those places where the thickness of the ice was greatest, and where the motion was (probably) quickest; where the glacier was compressed laterally, so that its power was distributed over a smaller area of rock-surface; and where erosion had produced ruts into which the glacier was pressed down, and out of which it could only extricate itself by a struggle.

Throughout the valley, in conjunction with the roches moutonnées, there are innumerable angular rock-surfaces which seem never to have been abraded by glacier. These lee sides287 are found right up to the bases of the existing glaciers. That is to say, they are found in spots which were not only covered by ice during the whole of the period in which the ancient glacier of Aosta extended to Ivrea, but have been covered by it in quite recent times. Glacier moved over them, probably, ages before the great glacier filled the valley; and, for aught we know to the contrary, it has done the same almost ever since. Yet, to all appearance, ice has never touched the lee sides, or, if it has done so, it has been done so tenderly, that the marks have been subsequently obliterated.

Now, whilst it may readily be admitted that atmospheric action is capable of completely effacing feeble traces of glacier-erosion,288 we cannot in the present instances admit any more. The contiguous surfaces to the lee sides which are highly polished and bearing fine striations, show that sun, frost, and water have done very little upon them since the ice departed. It would be absurd to suppose that these powers have been able to rub out all traces of ice-action (if the traces were other than very feeble) in one square yard, when in the next, upon the same rock, they have been unable even to roughen the surface, or get rid of fine scratches. It is doubly impossible to suppose that the rock-surfaces were uniformly ground down by ice, and that all the inequalities seen at the present time are the result of subsequent decomposition. I do not think anyone will have the hardihood to assert the contrary.

It is stated, therefore⁠—1. That the glacier-worn rocks in the Valley of Aosta are chiefly characterised by convexity, and principally belong to the class termed moutonnées. 2. That there are examples of roches nivelées in the valley; that they are rare in comparison with the roches moutonnées; and that they are mostly found upon the floor of the valley, or in places where it is narrowest, or where unusual obstructions have occurred. 3. That there are innumerable angular rock-surfaces (intermingled with these glaciated surfaces upon the floor and on the sides of the valley) which cannot have been fashioned since glacier covered the rocks. For the bearing of these facts upon Dr. Tyndall’s theory, I must now recapitulate from Chapter VI.

In the preliminary remarks in Chapter VI, after appealing to Studer’s observation that glacier-erosion was distinguished by the production of convex forms, I proceeded to show that such forms naturally resulted from glacier working upon surfaces which had been antecedently broken up by diverse actions; and pointed out that when glacier-action was long continued, the obliteration of all angular surfaces, and of almost all curves, was inevitable. I concluded, therefore (and accept all the responsibility which attaches to the conclusion), that the convexity of roches moutonnées was to be regarded as a proof that no great amount of glacier-erosion had occurred; that rock-surfaces with a small degree of convexity, which had obviously been glaciated, indicated a greater erosion; and that the degree of flatness bore a direct relation to the amount of power which had been employed. And further, that when unworn, angular rock-surfaces were found in the immediate vicinity of glaciated rocks, they were to be regarded as additional and confirmatory evidence that the depth of matter taken away by the glacier could not have been important, unless it could be shown that the angularity was due to subsequent operations.

Applying these conclusions to the case of the Valley of Aosta, we find⁠—1. That as recent denudation has been unequal, throughout the valley, to obliterate polish and fine striations on the rocks, we are unable to believe that the vast numbers of angular surfaces which are found in contiguity to the abraded ones can possibly have been produced subsequently to the retreat of the glacier. 2. Their existence in connection with innumerable convex glaciated surfaces throughout the valley, is irrefutable evidence that the valley was not excavated by glaciers. 3. The comparative scarcity of roches nivelées, combined with the other evidence, affords a strong presumption that the so-called excavation has not amounted, throughout the valley, to more than a very few feet of depth.

Hitherto, I have chiefly appealed to the bed (or floor) of the valley. Almost equally stubborn facts are obtainable from the slopes of its bounding mountains. If the valley had been excavated by glaciers, very emphatic traces would have been left behind everywhere⁠—above as well as below. I contend that if the entire valley had been excavated by glaciers, the surface of the rocks would have been as smooth as glass, from one end to the other, when the ice retired.289 Now, I have frankly admitted (see note 288) that, given sufficient time, sun, frost, and water are capable of destroying highly-glaciated surfaces; but I will not admit the possibility of such perfection of glaciation as I have just indicated being completely effaced (at heights exceeding 9,000 feet), while a few yards lower down ice-marks are seen, and seen everywhere. It is well known to all who have scrambled amongst the Alps, that those mountains are not glaciated from summit to base. The marks of the great glaciers of the olden time extend up to a certain height, and then they cease. This is the case throughout the Alps generally. The limit of glaciation is usually placed at about 9,000 feet. Above this limit the mountains are more or less rugged and angular. Below it, traces of glaciation are more or less apparent. Above it you seek in vain for glacier-worn rocks.290 Below it, they are found almost everywhere. Here is the evidence of Agassiz upon this point:⁠—

“Every mountainside in the Alps is inscribed with these ancient characters, recording the level of the ice in past times.⁠ ⁠… Thousands of feet above the present level of the glacier, far up towards their summits, we find the sides of the mountains furrowed, scratched, and polished, in exactly the same manner as the surfaces over which the glaciers pass at present. These marks are as legible and clear to one who is familiar with glacial traces as are hieroglyphics to the Egyptian scholar; indeed, more so⁠—for he not only recognises their presence, but reads their meaning at a glance. Above the line at which these indications cease, the edges of the rocks are sharp and angular, the surface of the mountain rough, unpolished, and absolutely devoid of all those marks resulting from glacial action.291 On the Alps these traces are visible to a height of nine thousand feet.”

—⁠Atlantic Monthly, Feb. 1864.

If these facts mean anything, they mean that great glaciers did not extend above this limit. I cannot suppose that Dr. Tyndall was ever a believer in the childish notion of the late Dollfus-Ausset, that glaciers are, and were, permanently frozen to the rocks at heights exceeding 9,000 feet, and therefore do not, and did not, wear them away!292 If that idea is correct, why are there any crevasses in glaciers at heights exceeding 9,000 feet? In what manner is the continuity of the glaciers maintained, if their lower portions move down, whilst their upper ones are immovable? Dr. Tyndall is far too well acquainted with glaciers to believe any such absurdity. I maintain that this evidence (although scarcely so conclusive as that which has preceded it) affords strong grounds for believing that the valleys of the Alps were never completely filled by glaciers, and therefore that the valleys were not excavated by glaciers.

The evidence from the mouths of the valleys of the Alps is not less hostile to Dr. Tyndall’s theory. For, observe, 1. The glaciers existed for a briefer period at the mouths of the valleys than at their upper portions. 2. The glaciers must have moved there, as a rule, at a slower rate than at the upper portions; because, as a rule, the gradients at the mouths were more moderate, and frequently (as in the case of the Valley of Aosta), there was a dead level. 3. The glaciers had usually received, before arriving at the mouths of the valleys, the whole of their most important affluents, and must have been rapidly diminishing in volume. The conclusion which is inevitable from these considerations is, that the glaciers must have exercised less erosion at the mouths of the valleys than at their upper portions; and this conclusion agrees very well with that arrived at by Dr. Tyndall himself, namely⁠—“Lower still the elevations diminish and the slopes become more gentle; the cutting power gradually relaxes, and finally the eroding agent quits the mountains altogether, and the grand effects which it produced in the earlier portion of its course entirely disappear.”293 But does this conclusion agree with the fact that the valleys are usually wider⁠—much wider⁠—at their mouths than elsewhere, and that the beds of the valleys at their mouths are at a lower level than at the upper extremities? If the glaciers had flowed up the valleys, these facts might be explicable; but they are unintelligible if the valleys were excavated by glaciers which flowed down them.

The mouths, the beds, the walls, and the terminations of the valleys, and the slopes of the mountains which bound them, proclaim alike that the present modelling of the Alps has been only slightly modified by glaciers. It would, however, be unreasonable to conclude, because such is the case, that glaciers are incompetent to excavate valleys under any circumstances; and, before taking leave of Professor Tyndall, it is only due to him to examine his opinions upon the subject. He is, like Professor Ramsay, a great believer in “soft places.” He believes not only that glaciers erode soft rocks more rapidly than hard ones (which is a reasonable belief), but he considers that all the chief inequalities which are now seen in valleys that have been worked upon by glaciers are due to the greater or less resistancy of the rocks to the action of the ice. “Were its bed uniform in the first instance, the glacier would, in my opinion, produce the inequalities.”294 Now, I could not differ greatly from Dr. Tyndall, if he were to say that glaciers must wear away soft rocks more rapidly than hard ones, and that they might, in consequence, ultimately produce inequalities, if set to work upon a smooth surface containing both hard and soft places. But he goes far beyond this. It is necessary for him to explain how it comes to pass that such masses are left behind as that at Montalto, at the entrance of the Valley of Aosta, or those upon which the castles of Sion stand. The valleys of Aosta and of the Rhône, he says, have been excavated by glaciers, yet here are these obstinate crags standing in the very centres of the valleys. They must have been exposed to the full force of the glaciers; nay, the ice-streams were evidently split by them, and had to flow upon either side and over them. “Assuredly,” says Dr. Tyndall, “a glacier is competent to remove such barriers, and they probably have been ground down in some cases thousands of feet. But being of a more resisting material than the adjacent rock, they were not ground down to the level of that rock.”295 Examination of such masses has led me to form a very different opinion. The contours of their rocks, upon the sides opposed to the direction of the flow of the glaciers, are frequently flatter, and suggestive of a greater degree of abrasion, than the adjacent and lower rocks. They have been lowered more, not less, than their surroundings. Yet the indications, are, as a rule, that these obtrusive crags have only been lowered to a trifling extent, and, most certainly, not thousands of feet. Still, let us suppose, for the sake of argument, that the adjacent rocks were actually softer, and were ground down a hundred or more feet upon each side of the hard crags, which, in consequence, became that amount above the level of their surroundings. The adjacent rocks would then, according to my opinion, have been prodigiously eroded; all their angles would have been obliterated; they would have become exceeding flat, and such forms as they would present would be characteristic of a high degree of glaciation. Yet we find that such is not the case. The rocks adjacent to the crags are frequently less flat, less abraded than the crags,296 and, to all appearance, their surfaces have not been lowered more than a very few feet. The conclusions are inevitable in such cases that the adjacent rocks have suffered less than the obtrusive crags, and that any real or imaginary softness of rock has not assisted glacier-erosion to the extent assumed by Dr. Tyndall.

The enormous amount of excavation assumed by Dr. Tyndall is further accounted for by him upon the supposition that glaciers are competent to “root masses (of rock) bodily away.”297 He seems to feel that mere grinding, rasping, and polishing would not be equal to the production of valleys, thousands of feet in depth, in any reasonable length of time, and so invokes this quicker process to get himself out of the difficulty. When and how Dr. Tyndall became possessed of this extraordinary idea I have no means of telling. Comparison of the following passages would lead one to suppose that it was acquired posterior to the publication of his Glaciers of the Alps:⁠—

“The lighter debris is scattered by the winds far and wide over the glacier, sullying the purity of its surface. Loose shingle rattles at intervals down the sides of the mountains, and falls upon the ice where it touches the rocks. Large rocks are continually let loose, which come jumping from ledge to ledge, the cohesion of some being proof against the shocks which they experience; while others, when they hit the rocks, burst like bombshells, and shower their fragments upon the ice. Thus the glacier is incessantly loaded along its borders with the ruins of the mountains which limit it.”

—⁠Glaciers of the Alps, Chapter on Moraines, p. 263 (1860).

“In the vast quantities of moraine-matter which cumbers many of the valleys we have also suggestions as to the magnitude of the erosion which has taken place. This moraine-matter, moreover, is only in part derived from the falling of rocks from the eminences upon the glacier; it is also in great part derived from the grinding and ploughing-out of the glacier itself. This accounts for the magnitude of many of these ancient moraines, which date from a period when almost all the mountains were covered with ice and snow, and when consequently the quantity of moraine-matter derived from the naked crests cannot have been considerable.”298

—⁠Phil. Mag., Oct. 1864, p. 271.

It has been already shown (see earlier in this chapter) that the notion that the Alps were completely covered by glaciers (or anything like completely covered) is erroneous, and the evidence which leads to that conclusion is clearly supported by the fact that a great proportion (I think it may be said the great proportion) of the materials are angular which compose the moraines of the past, as well as of the existing glaciers of the Alps.299 Their angularity is a certain proof that they were borne upon the glaciers, and were not transported under them. For, if they had been forced along underneath the ice, they would most certainly have become, at the least, sub-angular, or rounded or scratched. It is well known that this is what takes place at the present time in regard to debris underneath glaciers, and that the pebbles and boulders which are moved along in such a way acquire a character of their own which is unmistakable. The moraines, then, do not support, but clearly reject, Dr. Tyndall’s notion. Nor is the evidence of the rocks from which he supposes that masses have been “rooted away” less distinctly against him. How could masses be broken away without angular surfaces being left behind? and how is it that in those places where glacier-action has been most powerful, angular surfaces are most wanting? Dr. Tyndall appeals to the magnitude of the old glaciers, and to the enormous pressure which they exerted upon their beds, to explain his “rooting-away,” as confidently as if his case was completely proved thereby. Yet, in those places where glaciers have been the greatest, and where their pressure has been the most tremendous, and exerted for the greatest length of time, we find the rocks which have been worked upon are the most highly polished, the most flat in contour, and the most devoid of all angularity whatsoever!

It is clear, therefore, that the theory of “soft places,” as applied by Dr. Tyndall, cannot be sustained, and does not assist us to determine how far glaciers are competent to excavate valleys. The idea is plausible that soft rocks must suffer more rapidly than hard ones under the grinding of glaciers, and may be admitted; but it will be shown presently that there are things to be said upon the other side. The notion that glaciers root away masses of rock incessantly, or to any great extent, must be unhesitatingly rejected as being opposed to reason and to facts.300 However, “confining the action of glaciers to the simple rubbing away of the rocks, and allowing them sufficient time to act, it is not a matter of opinion, but a physical certainty, that they” would produce cavities or depressions of one sort or another. Given eternity, glaciers might even grind out valleys of a peculiar kind. Such hollows would bear little resemblance to the valleys of the Alps. They might be interesting, but they would be miserably unpicturesque. The hobnailed boots of Alpine tourists would be useless in them; we should have to employ felt slippers or skates.

I have advanced only a few of the more obvious objections to Dr. Tyndall’s theory. Many others might be urged. Had Dr. Tyndall confined himself to stating that glaciers were competent to excavate valleys, without offering examples, and without attempting to show how they would do it, various persons might have differed from him, but would have done so chiefly in degree. The declaration that the valleys of the Alps had actually been so excavated was a statement of a much more advanced and of a much graver nature. There are many persons, I am convinced, who would learn with satisfaction that he repudiates a doctrine which can be disproved in a multitude of ways, and which is flatly contradicted by a host of facts.

Whatever may be the popular opinion about Professor Ramsay’s theory regarding the formation of rock-basins, its author was entitled to credit for attempting to grapple with an acknowledged difficulty.301 Exceptions can be taken to it, of course. It may be asked, at the very outset, Is it absolutely necessary to accept this dogma that the only remaining agent is the denuding power of ice? Have we arrived at the end of all knowledge? And the cogency of the reasoning may be doubted by which the conclusion is derived, that rock-basins have necessarily been excavated by ice, because they are commonly found in districts which were formerly covered by glacier. It may be said that the connection which has been shown between the two302 may be nothing more than an accidental coincidence, and that, taken by itself, it is scarcely more convincing than that icebergs have made the Arctic seas, because those seas are full of icebergs. Such objections, however, do not touch Professor Ramsay’s main arguments; and I think that anyone who honestly endeavours to master them will feel that they are very ingenious, and by no means easy to refute.

It is impossible to deny a certain limited power of erosion to glaciers; and it is difficult to see why a great glacier should not make a hollow (a shallow one) if it were to come down upon a plain, and work there for a long time. For example, let A C B D, in the accompanying diagram, be a transverse section of a glacier which is moving over level ground, A G D F B. The glacier would naturally be thickest towards the centre, and its motion would probably be greatest in the same neighbourhood. It should therefore wear away its bed to a greater extent at or about the point D than anywhere else; and as the motion and weight of the ice would be greater at or about F and G than at points between F B or G A, so also would the erosion be greater thereabouts. In short, it is reasonable to conclude that in course of time the glacier might form a hollow in its previously level bed, such as is represented by the dotted line A E B. This would account for the hollowing out of rock-basins across their shorter axes. I do not merely think that this is what might happen, but that it is what must happen in course of time; and saying as much is practically admitting the power of glaciers to produce concavities in large areas of rock. It may seem now as if all were conceded that was required by Professor Ramsay. It is not so. Though his principle appears to me to be sound, his conclusions seem entirely unwarrantable. There is not the least doubt that rocks underneath the thicker parts of the existing glaciers are being worn away and polished to a greater extent than those which are covered by a small amount of ice. The same must have happened in the past. But these differences in the depth of erosion may, I think, be disregarded, because the difference between the maximum and the minimum in any given area would not amount to more than a very few feet; as the evidence which has already been recounted tends to show that glacier-erosion has been insignificant at any and every part of the valleys, and the valleys, it must always be remembered, were occupied by the glaciers for more time than the plains out of which Professor Ramsay would have us believe that his great lake-basins were excavated.

To the foregoing remarks the Professor has two answers. First, he has the idea that the retardation which a glacier would experience upon its arrival on a plain would tend to “heap-up” the ice (see earlier in this chapter). This is no doubt correct. He considers that the glacier would in consequence “attain an unusual thickness, thus exercising, after its descent, an extra erosive power.” Here we get into the region of surmises. To this we may demur. For he overlooks, or, at least, does not notice, that the glacier would be melting at a rapid rate, at or near its end, and that, in all probability, the extra ablation would counterbalance whatever thickening might arise from the tendency to “heap-up.” The “unusual thickness” by which he gets his “extra erosive power,” is entirely conjectural, and, judging by the glaciers of the present time, it is very doubtful if it had any existence whatever. If the Professor had pointed to a single glacier which was doubled in thickness through retardation, he would have materially fortified his argument; but, in the absence of any such evidence, we may be permitted to doubt if there is much force in his idea.303

Secondly, the great basins which Professor Ramsay believes were excavated by glaciers,304 are assumed to have been scooped out of areas filled by especially soft strata, which were removed with comparative facility, and at a rapid rate. Very eminent geologists disbelieve in the existence of these especially soft areas.305 Others, again, offer evidence which leads us to believe that some of the great Alpine lake-basins existed before the glacial period.306 But let us suppose that they are all wrong, and that the Professor was right. Let us suppose, too, that retardation actually doubled the thickness of the glaciers. Taking all this for granted, it is still incomprehensible how the ancient glacier of the Rhône managed to excavate the bed of the Lake of Geneva to the depth of 984 feet (opposite to Évian), when it was unable to remove a tenth part of that amount from the Valley of the Rhône (say between Zion and Sierre); for it was working for a greater length of time in the valley, and no doubt with a higher rate of motion, than it was upon the bed of the Lake of Geneva.

I have often wondered, considering the extent to which Professors Ramsay and Tyndall lean upon soft places, that they, or some of their pupils, have not thought it worth while to point out examples, upon a small and upon a large scale, of soft rocks which have been eroded by glaciers to a greater extent than harder rocks in their immediate vicinity. If Professor Ramsay was correct in supposing that glaciers wear away soft rocks with much greater rapidity than hard ones, it ought to be a very easy thing to produce examples. Yet, so far as I know, not one of the principal writers upon this subject has ever attempted to prove that glacier-erosion proceeds at an accelerated rate upon soft rocks, and is retarded by hard ones. It has been repeatedly asserted, or assumed, that such is the case, but proofs have been very rarely advanced.

Whilst this is the case, it has been frequently remarked by writers upon glacier-action (who do not seem, however, to have attached any particular importance to the fact), that quartz-veins are cut down, by the passage of ice over them, to the level of the rocks in which they are found. Quartz, one of the very hardest of commonly-diffused minerals, is unable to resist the grinding of glacier. Its hardness does not prevent its being polished down to the same extent as the much less resistant rocks which enclose it. If it suffered less than its surroundings, it would, of course, protrude. It does not, because it is eroded equally with the much softer rock. No distinction is made by the glacier, and the presence of the quartz is not sensible to the touch from any elevation or depression.

If glacier-worn rocks containing veins of quartz are exposed to the influences of sun, frost, and water, it is not long before the quartz begins to assert its superior resistancy. If it is in gneiss, the gneiss in contact with it speedily suffers. Minute cracks radiate from the junction of the two substances over the surface of the weaker material. Water enters the tiny fissures, and, expanding expanding under the influence of cold, rends away grain by grain, until at length, as in the accompanying diagram at A and B, little ravines are formed upon each side of the quartz-vein Q.307

If, on the other hand, glaciated rocks continue to experience the grinding of glacier, nothing of this kind results. The tendency of the quartz to protrude is incessantly checked, because, at the slightest suspicion of protrusion, it is attacked by the ice with increased power. If by any chance the quartz becomes elevated above the surrounding rock, it bears off the weight of ice from the surrounding rock, and this condition of affairs continues until both quartz and gneiss are brought to the same level.

There is little difference of opinion about these matters. It is perfectly well known that projections in the bed of a glacier are attacked by the ice, and that depressions escape abrasion through the protection afforded by the eminences.308 Hence it is that ultimately all angles and almost all curves are obliterated from the surfaces of rocks upon which glaciers work. Hence it is that in a district which has been severely eroded by glacier we find the rocks more flat⁠—that is, less convex⁠—than in one which has suffered less.

It is evident, then, that glacier does not and cannot dig away into soft places occupying limited areas. This is not a matter of opinion, but a certainty; and it seems to me to be entirely unwarrantable to assert, in the face of a well-ascertained fact like this, that the pools and small tarns lying in rock-basins (which are numerous in almost all mountainous countries) owe their existence to excavating power of glacier, merely because glacier has passed over the spots which they occupy; and, to say the least, to be injudicious to apply terms like “scooping out” to the rounding and polishing-up of the beds of such pools, because those terms convey an impression that is entirely erroneous. The hollows in which such pools are found would necessarily have been obliterated, not deepened, if the glaciers had worked for a greater length of time.309

Professor Ramsay held the directly contrary opinion. Unless I am entirely mistaken in regard to his ideas, he supposed that the beds of almost all pools, tarns, and lakes, which lie in true rock-basins, have been scooped out or excavated by glaciers. As a rule he did not consider that these lakes occupied hollows which were formed either entirely or in part through upheaval or subsidence (either or both), or antecedent erosion, but that these lake-basins are simply holes which glaciers have dug out. How or in what way the glaciers did the work, I have not the most remote idea. I turn the Professor’s pages over and over without gaining the slightest clue.310 But I gather from the Proceedings of the Geological Society, that it was from the examination of the small pools he first came to the conclusion that glaciers scooped out basins in rock; that he was at first “too timid to include the larger lakes”; and that becoming convinced the larger lakes occupied true rock-basins, he included them in the category of lakes which had been formed by the agency of glacier, because glacier alone, in his opinion, is capable of excavating true rock-basins!

The smaller idea has been shown to be fallacious, and it might be said that the larger one, which is built upon it, necessarily falls through. This is scarcely the case. The former deals with square yards, and the latter with square miles. A glacier we know, as a matter of fact, polishes down a quartz-vein in the same way as it does a bed of soft limestone. A plane which is adapted for planing wood may cut through a nail in a plank whilst taking off a shaving. But the plane is unable to take a shaving off a solid mass of iron, and it might be said, with some plausibility, that a glacier might be equally impotent if it had to work over square miles of quartz instead of square feet. To form a just idea of the probability of a glacier producing a lake-basin in one place (in soft strata), when during the same, or a longer, period, it only slightly erodes the surface at another place (hard strata), we ought to find out the effects which are actually produced by glaciers when working over a series of strata of unequal hardness, where the strike of the beds coincides with the direction of the motion of the ice. The idea, indeed, occurred to me, that insignificant quartz-veins might resist the grinding of glacier if they were worked upon longitudinally. It is not, of course, an easy thing to find a vein of quartz which has been worked upon longitudinally for a considerable distance; and I have never observed a better example than that which is described in the following paragraph.

In 1867, upon the shores of a fjord, about nine miles to the east of the settlement of Claushavn in North Greenland, I had the good fortune to discover the finest examples of roches nivelées which I have seen anywhere. The great interior mer de glace was near at hand, and a branch of it closed the inlet with an unbroken wall of ice, which was nearly a mile across. This branch had formerly filled the fjord, and had apparently covered the place to which I refer at no very remote date. Tremendous evidences of its power had been left behind. The gneiss upon the shores was literally levelled, and extended for hundreds of yards in continuous sheets, with polished surfaces destitute of all detritus, difficult to walk upon, for there was nothing to arrest the feet when they slipped. In these rocks there were two great veins of quartz, each three to four feet thick, which attracted notice at a considerable distance by their brilliancy when the sun fell upon them. These ran roughly parallel to each other for about eighty yards, and throughout that distance their direction had nearly coincided with that in which the glacier had moved. The glacier had passed over them at an angle of about 10°. Upon this quartz my hammer danced and rang, and made scarcely any impression. I chipped away the gneiss without difficulty. The glacier had worked upon two substances of unequal resistancy. Yet, if a line had been stretched between the highest points across any hundred feet of these sheets of rock, I do not think that any part of the rock would have been depressed one foot below the cord. The quartz, instead of standing up in ridges, as I thought it might have done, was cut down to the same level as the gneiss; the keenest scrutiny could not detect the least difference.

It was evident, from the entire obliteration of form, that these rocks had had enormous power exerted upon them, and that a not inconsiderable depth of rock had been removed. It is immaterial whether the effects had been produced by comparatively limited force spread over an enormous length of time, or whether by greater force in a less time. The same effects would have been produced if the same amount of abrading power had been exerted over an equal area of similar rock in the Alps. But it is doubtful, perhaps, if there is in the Alps an equal area of rock which can be compared for perfection of glaciation to that of which I have spoken. I think it may certainly be asserted that there is not either in the Valley of the Rhône or in the Valley of Aosta. The glacier-worn rocks of those valleys, and of the Alps generally, are notable for their convexity, and this affords evidence that the Alps have been subjected to less abrading power than the district in Greenland to the east of Claushavn. Now, if there is any truth in the assumption that glaciers dig away into soft rocks with much greater rapidity than into hard ones, there is, of course, greater opportunity for the exercise of this discriminative excavation when great power is exerted and when great erosion occurs, than when less power is exercised and less matter is removed. In Greenland, although enormous power has been exerted, and a considerable depth of rock has been undoubtedly removed, we find no appreciable distinction made in the treatment of two materials of very different degrees of hardness. How, then, is it possible to suppose that the prodigious amount of distinction could have been made which was assumed by Professor Ramsay in the less glaciated Alps?

These are by no means the only obstacles which stand in the way of acceptance of this theory.311 The difficulty is great of explaining how the glaciers excavated the rock-basins which exist, but it is still more troublesome to account for the nonexistence of those which ought to have been made. The Professor explained at considerable length why they would not be formed upon steep ground (§ 9), and I cordially agree with the first part of his remarks; but he went on to say that when a glacier descended into a “flat valley the case was different. There, to use homely phrases, the ice had time to select soft places for excavation.” “Why, then,” asked several eminent persons⁠—Mr. John Ball and Professor Favre amongst the number⁠—“are there not lakes in the Valley of Aosta?” The valley is precisely the kind of one in which they should have been formed. Its inclination, as I have shown (see note 262), is very moderate, and several parts of it (the site of the city of Aosta, for example) are almost plains. The glacier which occupied it, one would have thought, was thick enough to have ground out basins in the rock at any part, and retardation thickened it still more, occasionally.312 Are there no soft places throughout this great valley? Were there no accidents, which caused exceptional grinding on particular areas, throughout the whole of that long period during which the valley was occupied by glacier? Apparently there were not; anyhow, there are no lakes in the valley worthy of mention, nor are there, as far as can be told, any places where basins were excavated in the rock. The Professor evidently felt that the great glacier of Aosta did not behave as it should have done, and seemed to be nettled by the references which were made to its unaccountable remissness. “I have attempted,” said he, “to explain why the rock-basins are present, and not why they are absent.”313 He had, in fact, already accounted for their non-formation. He had shown that the great valleys of the Alps were approximately the same in their general features before they were filled with ice as they are at the present time. He had brought forward proof that this was the case with the Valley of Aosta, had shown that the great glacier which issued on to the plain at Ivrea had been unable to remove loose river-gravel, and had declared explicitly that the reason was that time was wanting. The entire passage is as follows:⁠—

“When lately south of the Alps, it was proved to me by Mr. Gastaldi,314 that at the mouths of the great Alpine valleys opening on the plain of the Po, there were ancient alluvial fan-shaped masses of gravel quite analogous to those that by the agency of existing torrents have issued from the gorges on either side (for instance) of the valleys of the Rhône or the Dora, or of those that still issue at their mouths. These were deposited on a plain rather lower than the existing one, above Pliocene marine deposits, at a time when the true mountain valleys⁠—at all events near their mouths⁠—were just about as deep as they are now; for the great glaciers that filled the larger valleys issued out upon and overflowed these low-lying river-gravels, and deposited their moraines above them, only in part scooping them away, apparently because the glaciers did not endure long enough of sufficient size to complete their destruction. No better proof could be required that in great part the valleys of the Alps were approximately as deep before the glacial epoch as they are at present; and I believe, with the Italian geologists, that all that the glaciers as a whole effected was only slightly to deepen these valleys.”

—⁠Phil. Mag., Nov. 1862, p. 379.

This passage was, I presume, intended to upset the doctrines of Dr. Tyndall, and it did so, conclusively, as far as the mouth of the Valley of Aosta was concerned. It struck almost as severely at the opinions of its author. Indeed, there is scarcely anything more damaging to be found in the whole of the remarks which the publication of his original memoir called forth. At the mouth of the Valley of Aosta, during the glacial epoch, the whole of the conditions were found which Professor Ramsay required for the formation of lake-basins. There was a vast glacier that issued out upon a plain, and which, in consequence of retardation, worked with unusual effect (?). It is demonstrable that it existed upon the plain for an enormous length of time; it is certain that it was extraordinarily thick; and the particular area upon which it worked was undoubtedly favourable for excavation. Yet the Professor was obliged to confess that the ice was unable to remove loose river-gravel lying upon the surface (indeed, that the glacier actually left another stratum of drift upon the gravel), and that the solid rock beneath did not experience any excavation whatever! There are many other places at which the same thing is known to have occurred, and so far from there being any especial tendency to excavate towards the snouts of glaciers, well-established facts lead rather to the opposite conclusion. A glacier which is bearing moraines always has those moraines brought together, jumbled together, towards its snout. Much of this moraine-matter falls down the sides of the glacier, and gets wedged between the ice and the bedrock; much more falls over the terminal face of ice, and forms a stratum over which the glacier has to pass. This continually happens as the glacier progresses; and until this stratum, interposed by the glacier itself, is ground away, the bedrock (or whatever may happen to be over the bedrock) is not assailed. The evidence is that the stratum of glacial drift which was deposited in this way at the mouth of the Valley of Aosta was able to resist the grinding of the glacier during the whole of its prolonged operations around Ivrea, and this fact gives, perhaps, a clearer idea of the extremely limited power of glaciers for excavation than any other which can be brought forward.

The weight of evidence seems to me to bear heavily against Professor Ramsay’s theory. In support of it, there is literally nothing more than the facts that glaciers abrade rocks over which they pass, and that there are numerous rock-basins (occupied or not occupied by lakes) lying within areas which were formerly covered by glacier. Here certainty ends. There are nothing but conjectures left, most of which have not even probability on their side. The idea that all petty pools and small tarns (which lie in rock-basins) occupy areas which have been subjected to special grinding, seems to me to be fully as absurd as the notion that each one lies in an area of special subsidence; and if all the geologists in the world were to swear that it was a solemn verity, I could not believe it, after what I have seen of the behaviour of glaciers upon rocks. The notion that the great lake-basins occupy areas that were filled with especially soft strata, which were subjected to exceptional grinding, seems to me not to be warranted. It is doubtful if the soft strata had any existence; it is doubtful if there was exceptional grinding; and it is highly improbable that the glaciers would have worked upon those basins at a rate ten, fifty, or a hundred times faster than they did in other places, even if the basins were filled with soft strata. More evidence is wanted upon this head; but it will be surprising if fresh facts upset those which have been already observed. Looking at all this doubt and conjecture on one side, and the numerous facts upon the other which prove that very small glacier-erosion has occurred throughout the Alps generally, and the extremely limited capacity of glaciers for excavation under any circumstances, it seems less probable that Professor Ramsay’s theory will work its way to general acceptance, than that it will quietly take its place amongst the exploded dogmas which are left behind in the progress of scientific inquiry.

Our thoughts were more than usually set upon roches moutonnées, and rocks of that genus, upon the 23rd of June 1865. My guides and I were reposing upon the top of Mont Saxe, scanning the Grandes Jorasses, with a view to ascending it. Five thousand feet of glacier-covered precipices rose above us, and up all that height we planned a way to our satisfaction. Three thousand feet more of glacier and forest-covered slopes lay beneath, and there, there was only one point at which it was doubtful if we should find a path. The glaciers were shrinking, and were surrounded by bastions of rounded rock, far too polished to please the rough mountaineer. We could not track a way across them. However, at 4 a.m. the next day,315 under the dexterous leading of Michel Croz, we passed the doubtful spot. Thence it was all plain sailing, and at 1 p.m. we gained the summit.316 The weather was boisterous in the upper regions, and storm-clouds driven before the wind, and wrecked against our heights, enveloped us in misty spray, which danced around and fled away, which cut us off from the material universe, and caused us to be, as it were, suspended betwixt heaven and earth, seeing both occasionally, but seeming to belong to neither.

The mists lasted longer than my patience, and we descended without having attained the object for which the ascent was made. At first we followed the little ridge shown upon the accompanying engraving, leading from our summit towards the spectator, and then took to the head of the corridor of glacier on its left, which in the view is left perfectly white. The slopes were steep and covered with new-fallen snow, flour-like and evil to tread upon. On the ascent we had reviled it, and had made our staircase with much caution, knowing full well that the disturbance of its base would bring down all that was above. In descending, the bolder spirits counselled trusting to luck and a glissade; the cautious ones advocated avoiding the slopes and crossing to the rocks on their farther side. The advice of the latter prevailed, and we had half-traversed the snow, to gain the ridge, when the crust slipped and we went along with it. “Halt!” broke from all four, unanimously. The axe-heads flew round as we started on this involuntary glissade. It was useless, they slid over the underlying ice fruitlessly. “Halt!” thundered Croz, as he dashed his weapon in again with superhuman energy. No halt could be made, and we slid down slowly, but with accelerating motion, driving up waves of snow in front, with streams of the nasty stuff hissing all around. Luckily, the slope eased off at one place, the leading men cleverly jumped aside out of the moving snow, we others followed, and the young avalanche which we had started, continuing to pour down, fell into a yawning crevasse, and showed us where our grave would have been if we had remained in its company five seconds longer. The whole affair did not occupy half-a-minute. It was the solitary incident of a long day, and at nightfall we reentered the excellent house kept by the courteous Bertolini, well satisfied that we had not met with more incidents of a similar description.