# Scrambles amongst the Alps/Chapter 16

CHAPTER XVI.
VALLEY OF AOSTA, AND ASCENT OF THE GRANDES JORASSES.
***"When we were boys, Who would believe that there were mountaineers Dew-lapp'd like bulls, whose throats had hanging at them Wallets of flesh?"......
Shakespeare.
The valley of Aosta is famous for its Bouquetins, and infamous for its Crétins. The Bouquetin, Steinbock, or Ibex, was formerly widely distributed throughout the Alps. It is now confined almost entirely, or absolutely, 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.
But the most sanguine person does not imagine that crétinism 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. But there is good reason to believe that there are at least 600 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 the sympathies of all as the remnants of a diminishing race, and 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"!! Even Tschudi himself calls this story wonderful. He may well do so. I disclaim belief in it,—the bouquetin is too fine a beast to indulge in such antics.
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 amounting 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 my last visit, 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 mètre 09 centimètres ​(about 5 feet 7 inches), and from the ground to the top of its back had been, apparently, about 77 centimètres. 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 BOUQUETIN.
The chase of the bouquetin is properly considered a sport fit for a king, and his Majesty Victor-Emmanuel, for whom it is reserved, is too good a sportsman to slaughter indiscriminately an animal which is an ornament to his dominions. Last year (1869) ​seventeen fell to his gun at one hundred yards and upwards. In 1868 his Majesty presented a fine specimen to the Italian Alpine Club. The members banqueted, I believe, upon its flesh, and they have had the skin stuffed, and set up in their rooms at Aosta. It is said by connoisseurs to be badly stuffed,—that it is not broad enough in the chest, and is too large behind. Still it looks well proportioned, although it seems made for hard work rather than for feats of agility. 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 3 feet 3½ inches from the ground to the base of its horns. Its extreme length is 4 feet 7 inches. Its horns have eleven well-marked rings, besides one or two faintly-marked ones, and are (measured round their curvature) 53½ centimètres in length. The horns of the specimen referred to on p. 296 (measured in the same way) had a length of only 53 1 centimetres, although they were ornamented with nearly double the number of rings, and were presumably of double the age of the former.
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 very numerous, and sometimes more plentiful than the prominent ones.
The Chef of the keepers (who judges by the above-mentioned indications) tells me that the ibex not unfrequently arrives at the age of thirty years, and sometimes to forty or forty-five. He says, too, that it is not fond of traversing steep snow, and in descending a couloir that is filled with it, will zig-zag down, by springing from one side to the other, in leaps of fifty feet at a time! Jean Tairraz, the worthy landlord of the Hotel du Mont Blanc at Aosta (who has had opportunities of observing the animal closely), assures me that at the age of four or five months it can easily clear a height of nine or ten feet at a bound!
Long live the bouquetin! and long may its chase preserve the health of the mountaineering king, Victor-Emmanuel. Long life to the bouquetin! but down with the crétin!
The peculiar form of idiocy which is called Crétinism 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 that it is not peculiar to the valley, and that there are crétins elsewhere. It is too true that this terrible scourge is wide-spread throughout the Alps and over the world, and that there are places where the proportion of crétins to population is, or has been, even greater than in the Valley of Aosta; but I have never seen, or heard of, a valley so fertile and so charming, of one which—apart from crétinism—leaves so agreeable an impression upon the wayfarer, where equal numbers are reduced to a condition which any respectable ape might despise.
The whole subject of crétinism 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 the most ​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 head-quarters. 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, more like brutes than men, commonly excite one's disgust by their hideous, loathsome, and A CRÉTIN OF AOSTA.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 crétins 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 crétinism would 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 crétinism, 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 Rhone valley is almost equally disfigured by crétinism, and in it, too, the extremities of the valley are slightly affected compared with the intermediate districts—particularly those between Brieg and St. Maurice This second example strengthens the conviction that the great development of crétinism in the middle of the valley of Aosta is not the result of accidental circumstances.
It was formerly supposed that crétinism 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. The notion seems to have proceeded from crétins being confounded with persons who were merely goîtred; or, at least, from the supposition that goître was an incipient stage of crétinism.
Goître, 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 goître has an intimate connection with certain geological formations. In harmony with these facts, it is found that infants are seldom born with goîtres, but that they develop as the child grows up; that they will sometimes appear and disappear from mere change of locality; and that it is possible to produce them intentionally.
It is not so certain that the causes which produce goître should be regarded as causes of the production or maintenance of crétinism. It is true that crétins are very generally goîtrous, but it is also true that there are tens of thousands of goîtrous persons who are entirely free from all traces of crétinism. Not only so, but that there are districts in the Alps, and outside of them (even in our own country), where goître is not rare, but where the crétin is unknown. Still, regarding the evil state of body which leads to goître as being, possibly, in alliance with crétinism, 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 goître 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 a positive advantage to be goîtred, as it secures exemption from military service. A goître 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 goîtrous 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 goître 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 drank), and to give to children who came to school lozenges containing small closes of iodine. It is said that out of 5000 goîtrous children who were so treated in the course of eight years, 2000 were cured, and the condition of 2000 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." These benighted creatures refused the Marshal's bâton and preferred their "wallets of flesh!"
No wonder that the Préfet for Haute-Savoie proposes that goîtrous 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 crétins. 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-goîtred population. The subject is worthy of serious attention. If goître is really an ally of crétinism, the sooner it is eradicated the better.
De Saussure substituted heat and stagnation of air as the cause of crétinism 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 crétinism of the Valley of Aosta. 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 crétins 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 crétinism of the Rhone valley.
Others have imagined that intemperance, poor living, foul habits, and personal uncleanliness, sow the seeds of crétinism, and this opinion is entitled to full consideration. Intemperance of divers kinds is fruitful in the production of insanity, 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 crétins are more numerous amongst the lower orders than amongst 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 crétinism, 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 corn-fields; 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 crétinism 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 crétinism. The disease is commonly found in valleys, on islands, or in other circumscribed areas, in which circulation is restricted, or the inhabitants are non-migratory; 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 crétins?" 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 notorious.
This conjecture explains, far better than the other guesses, why it is that crétinism 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. Accepting it, nevertheless, as a probable and reasonable 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 embarrassed 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 a railway from Ivrea to Aosta might possibly bring about, in a natural way, more movement than would be promoted by any legislation, and by this means the happiest effects might be produced.
There is little hope of practical results from attempts to cure ​crétins. Once a crétin, you are always one. The experiments of the late Dr. Guggenbühl demonstrated that some half-crétins 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 crétin could be altered. He essayed to modify some of the mildest forms of crétinism, 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 Aosta to contain 200 crétin beggars do much, unless the inmates are restrained from perpetuating their own degradation. Even the lowest types of crétins 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 crétins who will be born in the next generation will undoubtedly be offspring of crétin parents. It is strange that self-interest does not lead the natives of Aosta to place their crétins 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.
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 envelopes 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 crétins 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 crétinism 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 crétinism, 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. We, however, are not in a position to taunt others with neglect of inquiry. Only a few months 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 crétinism is not unknown in our own country.
Crétinism is the least agreeable feature of the valley of Aosta, but it is, at the same time, 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.
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 month for many centuries, and deposited there enormous masses of débris. 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. 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.
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 2130 feet above the floor of the valley! Professor Martins terms it "la plus elevee, la plus reguliere, et la mieux caracterisee des Alpes." It is locally called la Serra. The lateral moraine of the right bank also rises to a height of 1000 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 recently been published by Professors Martins and Gastaldi leaves nothing to be desired either in accuracy or completeness. 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 its crest 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 it was at its maximum altitude. Anyhow, at the mouth of the valley of Aosta, the thickness of the glacier must have been at least 2000 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 1055 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.
The space of 1055 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 ​onsidered 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 1055 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 2000 feet, 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 a period, and there are probably only one or two—such as the ancient glacier of the Rhone—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 more imperfectly known and more open to doubt; and I have selected it, on account of these reasons, as a valley which 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. It received much attention, and excited much criticism. I am not aware that Professor Ramsay replied to any of his critics, excepting Sir Roderick Murchison and Sir Charles Lyell. But 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; and, in endeavouring to present my reader with a resume 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,
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." It is in reference to such ones alone that his theory is 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."
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." He then proved that, in the Alps and elsewhere, ​§ 6. "Each of the lakes lies in an area once covered by a vast glacier." 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."
§ 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," "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."
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 rock-bound hollows."
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."
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."
§ 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."
The astonishment which Professor Eamsay's theory created had not subsided when Professor Tyndall brought forward opinions of an even bolder character, 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." 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;" 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.
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."—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."—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 last Birmingham meeting of the British Association, "that he was convinced that the glaciers of the Alps were competent to scoop out the valleys of the Alps," 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.
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 enquired, "Who shall decide between the disagreements of these doctors?" But it is surprising to find numerous persons accepting as gospel truth the contradictory dicta of these eminent men, and speaking and writing 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, but 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 rockforms 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 to-day, 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 natter portions of the valley we, should doubtless find higher polish, and still finer striations. Nevertheless, 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. This point is of no small importance; and, 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, 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 severe 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-sides 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, 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 any one will have the hardihood to assert the contrary.
It is stated, therefore—1. That the glacier-eroded 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 produced 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 at pp. 142-3, 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 am prepared to 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 number 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 ​elsewhere,—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. Now, I have frankly admitted (note to p. 323) 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 (say, at heights exceeding 9000 feet), while a few yards lower down ice-marks are seen, and seen everywhere. For 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 9000 feet. Above this limit the mountains are more or less rugged and angular. Below it, the traces of the glacial period are more or less apparent. Above it, you seek in vain for glacier-eroded rocks. Below it, they are found almost everywhere. Here is the evidence of Agassiz upon this point:—
"Every mountain-side 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 recognizes 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. 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 the great glaciers of the glacial period did not extend above this limit. For I cannot suppose that Dr. Tyndall is a believer in the childish notion of the late Dollfus-Ausset, that glaciers are, and were, permanently frozen to the rocks at heights exceeding 9000 feet, and therefore do not, and did not, erode them! If that idea is correct, why are there any crevasses at heights exceeding 9000 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." 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 that glaciers not only 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 eroded 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." Now, I could not differ greatly from Dr. Tyndall, if he were to say that glaciers must erode 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 Rhone, 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." 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, 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." 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 débris 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 bomb-shells, 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."—Phil. Mag., Oct. 1864, p. 271. |
It has been already shown (pp. 325-6) that the notion that the mountains 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. 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, subangular, or rounded or scratched. It is well known that this is what takes place at the present time in regard to débris 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 these 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 are and 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 in the least assist us to determine how far glaciers are competent to excavate valleys. The idea is plausible that soft rocks must suffer under the grinding of glaciers more rapidly than hard ones, 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. 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 valleys would bear remarkably little resemblance to the valleys of the Alps. They might be interesting, but they would be miserably unpicturesque. The hob-nailed boots of the 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, for the position taken up by the Doctor has been from the first an essentially false one, and has permitted him to be attacked from nearly every direction. Had he confined himself to stating that glaciers were competent to excavate valleys, without offering examples, and without attempting to show how they would do it, many persons might have differed from him, but would have done so chiefly in degree. The declaration that the valleys of the Alps had been so excavated was a statement of a much more advanced and of a much graver nature, and I cannot but think that in making it Dr. Tyndall has materially retarded the progress of knowledge. 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 is entitled to credit for having attempted to grapple with an acknowledged difficulty, and to be congratulated upon the number of ​valuable facts which he has elicited. 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 two 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 any one who honestly endeavours to master them will feel that they are very ingenious, and that they are 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 erode 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 is required by Professor Ramsay. It is not so. His principle appears to me to be sound, but his conclusions entirely unwarrantable. There is not the least doubt that rocks underneath the thicker parts of the existing glaciers are being eroded to a greater extent than those which are covered by a small amount of ice. The same must have happened during the glacial period. But these differences in the depth of the 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 p. 320). 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 could point to a single glacier which is doubled in thickness through retardation, he would materially fortify his argument; but, in the absence of any such evidence, we may be permitted to doubt if there is much force in his idea.
Secondly, the great basins which Professor Ramsay believes were excavated by glaciers, 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. Others, again, offer evidence which leads us to believe that some of the great Alpine lake-basins existed before the glacial period. But let us suppose that they are all wrong, and that the Professor is 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 Rhone managed to excavate the bed of the Lake of Geneva to the depth of 984 feet (opposite to Evian), when it was unable to remove a tenth part of that amount from the valley of the Ehone (say between Sion 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 adherents, 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 is 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, as far as I know, not one of the principal writers upon the 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 continually remarked by writers upon glacier-action (who have not, however, 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-eroded 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.
If, on the other hand, the eroded 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 it becomes elevated above the surrounding rock, it bears off the weight of the 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. 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 been less eroded.
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 the 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.
Professor Ramsay holds the directly contrary opinion. Unless I am entirely mistaken in regard to his ideas, he supposes 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 does not consider that these lakes occupy hollows which were formed either entirely or in part through upheaval or subsidence, (either or both), or antecedent erosion, but that the 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. 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, has often 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 fiord, 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 fiord, 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 excessive 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 pf 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 Rhone or in the Valley of Aosta. The glacier-eroded 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 Clanshavn. 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 is assumed by Professor Ramsay in the less eroded Alps?
These are by no means the only obstacles which stand in the way of acceptance of his theory. 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 non-existence of those which ought to have been made. The Professor explained at considerable length why they would not be formed upon steep ground (§ 9, p. 316), 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 (p. 313), 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. 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 feels that the great glacier of Aosta did not behave as it should have done, and seems to be nettled by the references which have been made to its unaccountable remissness. "I have attempted," said he, "to explain why the rock-basins are present, and not why they are absent."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:—
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 requires 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 is 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 bed-rock; 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 bed-rock (or whatever may happen to be over the bed-rock) 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, he has 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 popular 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 23d 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 tracked 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, 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. 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 GRANDES JORASSES AND THE DOIRE TORRENT, VAL FERRET (D'ITALIE).
* ↑ Tschudi's Sketches of Nature in the Alps.
* ↑ Probably stretched in skinning.
* ↑ Mr. King, in his Italian Valleys of the Alps, says, "In the pair (of horns) I possess, which are two feet long, there are eight of these yearly rings." It would seem, therefore (if the rings are annual ones), that the maximum length of horn is attained at a comparatively early age.
* ↑ Jean Tairraz was the leading guide of the late Albert Smith on his celebrated ascent of Mont Blanc.
* ↑ "Crétinism may be looked upon as being the highest stage of Idiocy, although it differs from it, in having a vitiated state of the body, in conjunction with the loss of the faculties of the mind. Thus it is composed of two distinct elements,—the one, Idiocy, the other, bad habit of body."—Blackie, On Crétinism, p. 6.
* ↑ It was stated a few years ago that one in twenty-five of the natives of the Canton Valais (which is chiefly occupied by the valley of the upper Rhone) were crétins. This would give about 3500 to the canton. At the same time the valley of Aosta contained about 2000 crétins.
* ↑ Voyages dans les Alpes, § 1033.
* ↑ Dr. Moffat communicated a paper on this subject at the last (1870) meeting of the British Association at Liverpool, in which he stated he had ascertained that in a Carboniferous district goitre was prevalent, and that it was absent on New Red Sandstone.
* ↑ Goître is endemic at Briançon, and frequently affects, temporarily, the soldiers who are stationed in that fortress. Chabrand (a doctor of Briançon) says that no less than one in twenty-five of the men of the 34th regiment of infantry, who were in garrison in 1857, became goîtrous during their stay. This regiment came from Perpignan, where the disease is not common.—Goître et Crétinisme endemique, Paris, 1864, p. 56.
* ↑ The substance of this paragraph is taken from the Bullettino del Club Alpino Italiano, No. 13, 1869.
* ↑ Blackie says that " Dr. Mottard mentions the case of a so-called goître well near St. Julien in Maurienne, the water of which encrusted the trees in the vicinity with lime, and the use of which produced goître in a couple of months; and he mentions five young men who had voluntarily drunk its water, and produced goître, in order to be free from military service." Chabrand, in the pamphlet already quoted, says, "It is deplorable that young people who have a swelling of the thyroid gland (in the Briançonnais), far from endeavouring to get rid of it, occupy themselves only making it bigger, in order to escape military service. Especially as the time of drawing for the conscription approaches, do they use every means supposed to be capable of producing goître; drink much water, take 'courses' with burdens" (on their heads?) "and tighten the cravat above the swelling. . . . From 1842 to 1847 inclusive, 91 in 1000 obtained exemption on account of goître in the Department of the High Alps." The same writer places the number of goîtrous persons in France at 450,000, and of crétins at 35,000 to 40,000.
* ↑ "Goîtrous persons, exempt from military service, remain in their native districts, marry, and thus cause the disease to become hereditary. If, on the contrary, they were drawn, and were sent into untainted departments (particularly those upon the sea-coast), they would return perfectly cured at the expiration of their term of service. Further, if goîtrous persons were not exempt, a greater number of healthy individuals would remain at home, would marry, and would become parents of sound and vigorous children."—Guy and Dagand.
* ↑ An instance was mentioned to me, in 1869, of a small proprietor in the Valley of Aosta, who had a wife and several healthy children, having, successively, two good years with his vines. He ate and drank the proceeds up, instead of husbanding his resources, and in the two following years two crétin children were born to him. Several indifferently-good years have succeeded since then, he has been obliged to live frugally, and has had several more children, all of whom are healthy. The parents are apparently free from all taint of crétinism.
* ↑ See Dr. Robert Christison On some of the Medico-legal Relations of the Habit of Intemperance, 1861; Dr. Edward Jarvis On the Causes of Insanity, 1851; and Reports of the Commissioners in Lunacy.
* ↑ Dr. Blackie gives the remarkable instance of "the island of Medworth (Niederworth?), near Coblence, where the inhabitants hold no connection with those on shore, and consequently intermarry constantly with one another." This island, according to Dr. Blackie, had no less than 40 crétins out of a population of 750.
* ↑ The case of the Val Sesia is not strictly in point, since it is not a tributary of the Val d'Aoste, but it may be quoted to show the extent to which this migration goes on. Mr. King says, "The population of the whole Val Sesia being estimated at 35,000, it is evidently utterly unable to maintain a tithe of that number from its own resources. The necessary result is, a regular periodical migration of all the able-bodied and active males, for varying lengths of time, into different parts of Europe.... A large number of the towns of Italy and France, as Genoa, Milan, Turin, and even Paris, are supplied with an immense influx of skilled labourers and artificers from these Vals. Some idea of the extent of this migration may be formed from the fact, that 8000 Val Sesians leave their homes annually, many of them for years."—Italian Valleys of the Alps, p. 373.
* ↑ It may be mentioned, as a link in the evidence, that the Department of the Hautes Alpes (which contains a prodigious number of crétins) has, according to Chipault, a larger proportion of deaf and dumb persons to its population than any other department of France, viz. 1 in 419. The Department of the Basses Pyrenees comes next, with 1 in 677.
* ↑ "M. Rambuteau (Prefet of the Department of the Simplon, under the first Napoleon) and M. Fodere assure us, that at the close of last century the number of crétins in the Canton Valais diminished to a very great degree. The former attributed this amelioration to the embankment of the Rhone, and the draining of the marshes; to the clearing of the land; and the consequent changes in the character of the inhabitants, who became more industrious and active, and less given to gluttony and drunkenness. The latter author rather imputed it to the opening of the great pass of the Simplon, and consequent more easy communication with other countries, the people being thus more incited to bestir themselves," etc.; Blackie, p. 53. This testimony, from authors who held totally different opinions as to the origin of crétinism, is strongly confirmatory of the conjecture last advanced.
* ↑ "Le crétinisme achevé est incurable; l'état physique et intellectuel des crétineux et des demi-crétins est susceptible d' amélioration par un traitement convenable, des soins et l'éducation; mais jamais on ne pourra faire d'eux des hommes complets sous le rapport physique, moral, et intellectuel."—Guy and Dagand on Crétinisme dans le Département de la Haute-Savoie.
* ↑ Great expectations were raised some years ago by the reports of Dr. Guggenbühl, and by those of visitors to his establishment on the Abendberg, at Interlachen; but they have been disappointed, and the institution itself has been closed.
* ↑ At the expense of some unknown charitable person. Besides this establishment, there is an hospital at Aosta, belonging to the order of St. Maurice et Lazare, containing twelve beds for crétin children.
* ↑ It should be stated, that some of the clergy, at least, refuse to unite the worst kinds of crétins. I have heard it said, however, that all are not so particular; and, again, others have told me that crétins are never legally married in the valley of Aosta. I imagine the truth to be, that some of the priests are scrupulous, and that others are not. The evidence of the natives upon this subject was so conflicting, that I applied to the Canon Carrel (of Aosta) for information. His answer was sufficiently explicit as to the general custom:—"II y a des crétins qui parlent avec une certaine intelligence, et qui sont capables d'apprendre quelques vérités et quelques notions nécessaires aux devoirs sociaux. Ceux-ci contractent quelquefois mariage. Quant à ceux qui ont l'intelligence très obtuse, on ne leur permet pas le mariage, quoiqu'ils puissent encore engendrer ce qui tient plus de la loi naturelle que de la loi civile."
* ↑ For further information upon crétinism, see the works of Ferrus, Niepce, Fabre, Séguin, Nystrom, Morel, etc.
* ↑ Debate on the Census Bill, on the motion by Sir John Lubbock to insert the words "whether married to a first cousin." The opponents of Sir J. Lubbock's motion should read Chipault Sur les Mariages Consanguines: Paris, 1863.
* ↑ De Saussure, §§ 954, 1030.
* ↑ See General Map.
* ↑ I am indebted for this fact to Professor Gastaldi.
* ↑ Revue des Deux Mondes.
* ↑ Essai sur les terrains superficiels de la Vallee du Po, extrait du Bulletin de la Société Géologique de France, 1850.
* ↑ See Forbes' Occasional Papers on the Theory of Glaciers, pp. 193-95, and Travels through the Alps of Savoy, 2d ed. pp. 86-7, for information bearing upon the mean annual motion of existing Alpine glaciers. In the former work an account is given of the discovery of the remains of a knapsack ten years after it had been dropped in a crevasse, at a horizontal distance of 4300 feet from the place at which it had been lost, showing an average annual motion of 430 feet. In the latter work there is a relation of the recovery of the remains of a ladder used by De Saussure, which had travelled about 13,000 feet in 44 years, or 295 feet per annum. Forbes says that the first of these two examples is better ascertained in all its particulars than the other. It should be observed that the knapsack in question made the descent of the well-known "ice-fall" of the Glacier de Talèfre, and that there was a difference of level between the place at which it was lost and that at which it was found of 1145 feet; that is to say, it descended one foot in every four that it advanced. This rapid descent undoubtedly accelerates the motion of the Glacier de Talèfre. The town of Ivrea, on the other hand, is 768 feet (Ball) above the level of the sea, while Entrèves (at the foot of Mont Blanc) is 4216 feet (Mieulet). So that the glacier which once spread over the sites of these two places (which are about 65 miles apart) descended by an average gradient of almost exactly 1 in 100. This moderate rate of inclination would as certainly tend to retard the motion of the glacier.
* ↑ This is understating the case. The thickness of the glacier exceeded 2000 feet at the mouth of the valley, "where it had a width of 5¼ miles. In the valley itself, where the width was less, the thickness appears to have been considerably more than 2000 feet.
* ↑ Professor Ramsay's paper was printed in the Quarterly Journal Geol. Soc., August 1862. The germs of the Professor's theory are to be found in his Old Glaciers of Switzerland and North Wales, 1860, pp. 86, 107, 109, 110.
* ↑ October 1864, and April 1865.
* ↑ I shall also occasionally refer to his Physical Geology and Geography of Great Britain, and to Old Glaciers of Switzerland, etc.
* ↑ Physical Geology and Geography of Great Britain, p. 86.
* ↑ Proc. Geol. Soc., Aug. 1862, p. 200.
* ↑ Physical Geology and Geography, p. 88.
* ↑ Proc. Geol. Soc, p. 199.
* ↑ Phil. Mag., October 1864, p. 303.
* ↑ Proc. Geol. Soc., 1802, p. 188.
* ↑ Ibid. p. 200.
* ↑ Phil. Mag., October 1864, p. 305.
* ↑ Old Glaciers, pp. 104-5.
* ↑ Phil. Mag., April 1865, p. 298.
* ↑ Phys. Geol. and Geog. p. 90.
* ↑ Phil. Mag. Sept. 1862.
* ↑ Old Glaciers of Wales, p. 94.
* ↑ Phil. Mag. Nov. 1862, p. 379.
* ↑ See pp. 341-2.
* ↑ The italics are not in the original.
* ↑ Comparison of the sentences placed in italics, with the preceding one from Dr. Tyndall, will show how irreconcilable were the opinions of these two writers.
* ↑ Birmingham Daily Post, September 13, 1865.
* ↑ It must not be understood that anything of the nature of a controversy was carried on, in the magazines cited, by the two Professors. They did not refer to each other by name; but it was impossible to read the passages which have been quoted, without feeling that they were intended to be replies to objections on the other side.
* ↑ See p. 146.
* ↑ See p. 145.
* ↑ Or, given sufficient time, of destroying highly-glaciated surfaces.
* ↑ See p. 152.
* ↑ It is not, of course, meant that there are no traces of glacier-action above 9000 feet, upon rocks bounding, or surrounded by, the existing glaciers. There are, for example, many islands of rock in the Alps, surrounded by glacier, at elevations considerably exceeding 9000 feet, which are highly glaciated. I refer to those mountains which are away from the existing glaciers, and which have never been influenced by them.
* ↑ The italics are not in the original.
* ↑ See Matériaux pour l'étude des Glaciers, vol. i. part iii. p. 11. The same idea is repeated in many other places in the same work.
* ↑ Phil. Mag., Oct. 1864, p. 264.
* ↑ Phil. Mag., Oct. 1864, p. 266.
* ↑ Phil Mag., Oct. 1864, p. 266.
* ↑ I do not know an instance where the reverse is the case.
* ↑ Phil. Mag., Oct. 1864, p. 265.
* ↑ See p. 245.
* ↑ I am, of course, aware that there are glacial deposits in Great Britain, and elsewhere, in which sub-angular and scratched stones are largely in excess of those which are simply angular. The manner in which such deposits were formed is not yet clearly understood.
* ↑ It has been already admitted (§ 5, p. 145) that the minor asperities of rocks suffer, and may be actually crushed or scraped away. That this happens cannot be doubted, but this (comparatively) speedily comes to an end. It is mere brushing of the surface preparatory to polishing.
* ↑ Professor Ramsay claims to be the first who has pointed out this connection. Professor Dana extends the statement still further:—"Another great fact that belongs to the Drift latitudes on all the continents, and may have the same origin, is the occurrence, on the coasts, of fiord valleys,—deep, narrow channels, occupied by the sea, and extending inward often 50 or 100 miles."—Manual of Geology, 1867, p. 541.
* ↑ No one can consult the excellent map which accompanies Martins' and Gastaldi's Terrains Superficiels without seeing in a moment, from the disposition of the moraines, that the great glacier of Aosta spread itself out directly it arrived upon the plain. Hence, any material thickening through retardation was impossible. It can readily be shown that this spreading-out frequently occurs to the glaciers of the present time, when they pass from confined places on to open spaces (places where the valleys widen).
* ↑ The basins of the lakes of Geneva, Neuchatel, Thun, Zug, Lucerne, Zurich, Constance, etc. etc.
* ↑ For example, see the remarks of Prof. Favre upon the Lake of Geneva, in Phil. Mag., March 1865.
* ↑ Sir Charles Lyell, for example. In regard to the lakes of Zurich, etc., see his Antiquity of Man, 3d ed., pp. 314-16.
* ↑ In Greenland I have seen gneiss cracked away from quartz-veins in glacier-eroded rocks, in this manner, to a depth of two inches and more. Where the same veins had been protected from the atmosphere, they were without the little trenches on each side. To the same effect see Geikie On Modern Denudation, Trans. Geol. Soc. Glasgow, 1868.
* ↑ "In descending from the summit of the "Weisshorn on the 19th of August last I found, near the flanks of one of its glaciers, a portion of the ice completely roofing a hollow, over which it had been urged without being squeezed into it."—Tyndall's Mountaineering in 1861, p. 73. Dr. Tyndall's testimony is especially valuable, because he is by no means prejudiced in favour of the views which I am supporting.
* ↑ Sir Charles Lyell remarks with much force, in the 6th ed. of his Elements, p. 170, "Where opportunities are enjoyed of seeing part of a valley from which a glacier has retreated in historical times, no basin-shaped hollows are conspicuous. Dome-shaped protuberances, the roches moutonnées before described, are frequent; but the converse of them, or cup-and-saucer-shaped cavities, are wanting." The justness of these observations is undeniable. The perusal of Professor Ramsay's papers would lead any one personally unacquainted with glacier-eroded rocks to conclude that the reverse was the case—that saucer-shaped hollows were abundant, or, in other words, that concavities predominated.
* ↑ I cannot find anything more explicit than this:—"The greater number lie in rock-basins formed by the grinding of glacier-ice." This is simple assertion; now for the proof. "Sometimes in the convolutions of the strata (conjoined with preglacial denudation subsequent to the contortion of the beds) softer parts of the country may have been scooped out; but perhaps more generally they were formed by the greater thickness and weight of glacier-ice on particular areas, due to accidents to which it is now often difficult or impossible to find the clue."—Proc. Geol. Soc., 1862, p. 188.
* ↑ For some of the more important objections, see Sir R. Murchison's Address to the Royal Geog. Soc. 1864; Sir C. Lyell's Antiquity of Man and Elements of Geology; Prof. Studer's Origine des Lacs Suisses; Prof. Favre in Phil. Mag. March 1865; and Mr. John Ball in Phil. Mag. Feb. 1863.
* ↑ Professor Guyot has remarked striations ascending towards the mouth of the valley in places where the valley narrows. See Gastaldi's Terrains Superficiels.
* ↑ Phil. Mag., Oct. 1864, pp. 305-6.
* ↑ Professor Gastaldi had published the same fact more than twelve years before. "On voit au ravin du torrent de Boriana, qui descend de la tourbière de San-Giovanni, que le terrain glaciare eparpillé supporte la moraine superficielle, et se confond lui-même avec le diluvium Alpin qui repose inferieurement sur le pliocène marin."—Terrains Superficiels, 1850.
* ↑ For route, see map of the chain of Mont Blanc.
* ↑ The ascent of the Grandes Jorasses was made to obtain a view of the upper part of the Aig. Verte. and upon that account the westernmost summit was selected in preference to the highest one. Both summits are shown upon the accompanying engraving. That on the right is (as it appears to be) the highest. That upon its left is the one which we ascended, and is about 100 feet lower than the other. A couple of days after our ascent, Henri Grati, Julien Grange, Jos. Mar. Perrod, Alexis Clusaz, and Daniel Gex (all of Courmayeur), followed our traces to the summit in order to learn the way. As far as my observation extends, such things are seldom done by money-grasping or spiritless guides, and I have much pleasure in being able to mention their names. The highest point (13,799) was ascended on June 29-30, 1868, by Mr. Horace Walker, with the guides Melchior Anderegg, J. Jaun, and Julien Grange.