Chapter II: Front Matter (2)

Within that time, however, it has been discovered that there are a number of other deposits of asphalt well adapted to use for street pavements. A very large deposit containing a high percentage of bitumen and very little mineral matter is located near the coast in the State of Bermudez, in Venezuela. Large deposits have been found in several places in California, and in Utah, Kentucky, and Texas, and a number of other places. The Kentucky product is classed as a natural rock asphalt, as it is a sandstone impregnated with bitumen. It has been mixed with about an equal portion of German rock asphalt and used with very satisfactory results in Buffalo. These asphalts are quite different in their composition, and each requires somewhat different treatment. The Bermudez, being richer in bitumen and softer, requires the addition of very little flux. The California deposits furnish their own flux in a liquid asphalt or maltha, which is almost absolutely pure bitumen, and the use of petroleum residuum is thereby avoided altogether.

It has been recognized since 1836 that the bitumen which forms the greater part of natural asphalts can be separated into two substances, which have been commonly known as petrolene and asphaltene, the former of which possesses the cementitious qualities essential to the making of a successful pavement. Instead of the arbitrary names--petrolene and asphaltene--these substances are sometimes more aptly designated as active and inert bitumen. It has been found that of the bitumen extracted from asphalts which have given the most satisfactory results in making street pavements, sixty-nine per cent or more is soluble in petroleum naphtha having a specific gravity of 72° Beaumé.

An asphalt pavement can not be economically kept in good condition unless every defect which may develop is immediately repaired. When the smooth, hard surface is once broken, disintegration proceeds very rapidly, and a large hole is soon formed. The more general distribution of smooth pavements, however, will tend to distribute the traffic more evenly, and the increasing use of rubber tires and rubber shoes for horses, to say nothing of the probably quite general use of motor vehicles, within the next decade will result in the elimination of the forces at present most destructive to pavements.

Much regret is often expressed that asphalt pavements should be so frequently opened for the purpose of laying or obtaining access to subsurface pipes and conduits, and thereby mutilated. As a matter of fact, there is no pavement at present in use which can be so effectively and satisfactorily restored as asphalt. When skillfully done, almost no trace of such an opening can be found.

The first question to arise, when it has been determined to pave a street, will be the selection of material, or the kind of pavement to be laid. In determining this, the governing considerations will be the traffic to be sustained, its density and character, the rate of grade, and the presence or absence of railroad tracks.

If the traffic be very heavy and the street given up wholly to business, ease of traction, durability, and economy of maintenance are of first importance, while quiet, comfortable riding, and beauty can be sacrificed to them. Many efforts have been made to determine the relative force required to draw a load over different kinds of surface under similar conditions. The following is from a table compiled by Mr. Rudolph Hering, from different authorities, the force being that necessary to move one ton on a level grade at a speed of three miles an hour:

KIND OF ROAD. Pounds.

Ordinary dirt road 224
Ordinary cobblestone 140
Good cobblestone 75
Common macadam 64
Very hard, smooth macadam 46
Good stone block 45
Best stone block (London) 36
Asphalt 17
Granite tramway 12½ to 13½
Iron railway 8 to 11½

The question of durability occurs next, and the different kinds of pavement which may be considered for city streets may be rated as follows, it being assumed that the traffic is not excessively heavy:

KIND OF PAVEMENT. Life in years.

Best granite block on concrete 30
Granite block laid on sand 20
Belgian trap 20
Cobblestone 18
Asphalt 15
Best wood--rectangular block 10
Vitrified brick 12
Macadam 8
Cedar block--round--on sand 5

No class of municipal work comes so near to the daily life of an urban population--both the business and the home life--as the surface improvement of city streets, and no expenditure is too great (provided the work is skillfully and honestly done) to make them smooth, clean, sanitary, and beautiful.

TYPICAL CRIMINALS.

BY SAMUEL G. SMITH, LL. D.

If the question of a criminal type, defined by certain marks of a physical nature and emphasized by accompanying mental and moral characteristics, were confined to the technical speculations of a special craft of scientists, the public would have little interest in the spread of the doctrines of Cesare Lombroso and his _confrères_ in this country. When it is believed, however, that certain men and women are committed to prison or condemned to death not on account of crimes in any ethical sense, but because of spontaneous actions from vicious impulses beyond their control, the subject affects the administration of law, the theory of punishment, and the safety of society.

Lombroso and the Italian school say that they have discovered a type of man who is born a criminal, and who may be recognized by a Mongolian face, abnormal features, ill-shaped ears, unsymmetrical skull, and various psychical peculiarities, which are the result of bad organization. This doctrine is illustrated by descriptions of criminals who have the abnormalities, and in the hands of skillful writers the case is made very plausible. The theory is in harmony with so much popular modern thought, which loosely interprets the doctrine of evolution by a crass materialism, that it has infected American prison literature, while it has never misled those men to whom practical experience has given the most right to have an opinion on the subject. The sense of personal responsibility is still the foundation of social order, and if in truth there is no such thing, the world is awake at last from its dream of morality; righteousness is resolved into heredity, structure, and habit; living is a mere puppet show, and the wreck of things impends. If Lombroso is right, modern scientific methods are sure to prove him so, and we shall have at last sound theories; but we shall have no world in which they can be used, for the dissolution predicted by Herbert Spencer will have come.

Exceptional opportunities for the study of the abnormal classes in the institutions of this country and Europe have given me a personal interest in the question of the criminal type. I have discovered that the criminal anthropologists do not choose for comparison with the prison population their normal men from the ranks where the criminal classes are recruited. Blackwell's Island has no more peculiar inmates than abound in sections of New York near the East River; the residents of the Whitechapel district of London may be compared with the inmates of Pentonville, to the distinct credit of the latter; and the man in Roquette is no worse off in body than scores whom I have seen in certain localities south of the Seine. The fact is, no human body exists which is not in some respects abnormal. The number of abnormalities and their extent depend upon a variety of circumstances, among which are food, climate, occupation, and the incidents of birth itself, as well as the various forms of infantile disease. I will undertake to find enough physical peculiarities, in any locality, or among the members of any profession, to establish any physical theory which may be propounded.

It occurred to me to try an experiment in a manner entirely different from the usual criminal researches. Having been very familiar with a certain prison for many years, I requested the warden, who is a very able man in his profession, to send me the photographs of ten or a dozen men whom he regarded as the most representative criminals in his population of some five hundred persons. The warden was not informed of the use I intended to make of the material, and supposed it was for illustration in university class work. Later, he gave me the Bertillon measurements of the men, with an epitome of their history. A number of these men I have known for years. So far from this selection supporting the modern theory of a criminal type, it confutes it in a conspicuous manner. The abnormalities are slight, and there is as great a diversity among the men as could be asked. It must be remembered that these cases were selected by a shrewd and competent official, solely upon their criminal record, and not in the interests of any theory whatever.

Of course, the men do not look well, but neither would any ordinary company of citizens if their heads were shaved and they were put in prison dress. I am always shocked by the changed appearance of the men after the prison transformation. Young embezzlers of elegant figure, who have moved in good society without a question, easily look the rascal behind prison walls.

The first group are murderers. No. 1 murdered his daughter because she insisted upon going to a party against his wishes. He has the head of a philosopher. It was his first crime. It may be noted that tattooing is supposed to be common among criminals. This man is tattooed, but committed no crime until fifty years of age, and was a deputy sheriff for some years. No. 2 did not kill his victim, but the assault was murderous, and the escape from death was accidental. It is difficult to discuss the negro in crime without entering into racial and social questions beyond the present limits. No. 3 has a very good head, an excellent ear, and, barring the expression, a pleasing face. He has a life sentence for murder. He is the worst man in the prison. I have for years believed him to be insane. His family is criminal. His father murdered his mother in a brutal manner before the child's eyes, when No. 3 was only eight years old. He himself has committed several desperate assaults, growing out of his persistent mania of persecution. No. 3 is not morally responsible, and there are usually two or three such prisoners out of a thousand subjects.

The second group are very diverse in structure and temperament, but have committed the same kind of crime. No. 1 is a confidence man and a forger. He is a crafty and an habitual criminal, has served terms in various prisons, is keen of intellect, well educated, has traveled in many countries, and is a citizen of the world.

No. 2 is a confirmed forger, and has served several terms in prison for the same offense. He is a skillful bookkeeper, has an attractive manner, and as soon as he is out in the world secures employment and plans his next crime.

No. 3 is a counterfeiter. His head is small, but of excellent shape, and he has rather a refined physical organization. His criminal record is bad, and he has served at least one term before for the same offense. His imagination, temperament, and vices would select him as a person who would be guilty of a very different and more fleshly kind of crime. The group is formed by the correlation of crime; they have nothing in common in physical organization.

The third group are thieves. No. 1 is a confirmed criminal, and has served several terms in prison. He is the tallest man in the list. His head is "long" and well formed, and his features are regular. His expression indicates power of sustained thought, and his peculiar appearance is not due to his kind of crime, but to his habit of mind. He is a pessimist of the first rank, and hates the world, his fellow-men, and perhaps himself most of all. He will not work when at liberty, thinks that society is totally depraved, and that war upon it is the only proper mission in life. He is pre-eminently the antisocial man.

No. 2 is really a pleasing fellow. He is tender, sympathetic, and pious. Under proper circumstances he might have made an admirable Sunday-school superintendent. He is plausible, insinuating, and winning. In temperament, feeling, and social habit he is the complete antithesis to No. 1. He is a most dangerous criminal, and has a black and varied record.

No. 3 is a man of lower grade of organization and habit, but he is a criminal by profession. He is an idle and worthless vagabond, but he is an accomplished thief. He makes an excellent prisoner, obedient to the rules, industrious, and seemingly anxious to improve. In fact, the prison furnishes his best environment, for it is only there that he is at peace with himself and his world.

The last two men presented are contrasts. No. 1 is an accidental criminal. His previous history and character give strong grounds for the belief that, under pressure of want for the necessaries of life, he was led astray by a man older and stronger than himself. It is not likely that he would repeat his fault. No. 2, on the other hand, is a sexual pervert of the worst kind, whose case seems so hopeless that perpetual imprisonment is indicated as the only relief for him, and the only safety for society. Apart from the expression of his eyes, caused by an irregular focus, there is nothing marked about the face. The head is of a pronounced "broad" type, but, on the other hand, he comes from a province of Germany where that type is dominant.

To complete the experiment, I submitted these portraits to a number of gentlemen, and to no two of them at the same time, for their opinions of the cases. The informal committee represented the different professions which might be expected to fit men for observation, for there was a lawyer, a physician, a railway president, a criminal judge, and a college professor. Each of them is eminent in his special field. The committee was manifestly handicapped by the shorn head, the prison dress, and the lack of the accessories of masculine ornamentation, such as collars and cravats. The committee was asked to name the crimes, and to group the men according to their criminal record. Each opinion differed from the other, and all were wide of the mark. The shrewd lawyer thought the accidental criminal "might be guilty of anything." It was only the college professor, the last man of the company from whom anything might properly be expected, who was able to select the worst two cases with the remark, "These men are degenerates." But while the committee was at work on the photographs the writer was at work on the committee, and actually discovered more anomalies of organization in these distinguished citizens than are apparent in the criminals. After this remark it is necessary to withhold their names, though some of them are men of national reputation.

It is time to reassert with increasing emphasis the personal responsibility of the individual, and to insist upon the enthronement and guidance of conscience. There are certainly social and economic reasons for crime, some of which the writer has pointed out elsewhere, but the chief fact in human life is the power of self-determination. The chief causes of crime, outside of personal and moral degradation, are psychical and not physical. The reader of history can not fail to have noted that relation of prevalent ideas to conduct which is so conspicuous in human affairs. The scenes of blood and desolation characteristic of the French Revolution are directly traceable to the doctrines which prepared the way for anarchy, but not for rational freedom.

We have had our attention directed to the contagion of suicide which has marked the last half decade. But Lecky tells us that suicide was made practically unknown in the civilized world by the spread of Christianity and its beliefs in the dignity and sanctity of man. The present contagion will disappear not as the result of food, or raiment, or houses, or any other material good, but by a revival of practical faith in the human soul and its capacity, in human righteousness and its obligation.

A CENTURY OF GEOLOGY.

BY PROF. JOSEPH LE CONTE.

[_Concluded._]

THE AGE OF THE EARTH.

Until almost the beginning of the present century the general belief in all Christian countries was that not only the earth and man, but the whole cosmos, began to exist about six thousand to seven thousand years ago; furthermore, that all was made at once without natural process, and have remained substantially unchanged ever since. This is the old doctrine of the supernatural origin and substantial permanency of the earth and its features. Among intelligent and especially scientific men this doctrine, even in the eighteenth century, began to be questioned, although not publicly; for in 1751 Buffon was compelled by the Sorbonne to retract certain views concerning the age of the earth, published in his Natural History in 1749.[1] Remnants of the old belief lingered even into the early part of the present century, and may even yet be found hiding away in some of the remote corners of civilized countries. But with the birth of geology, and especially through the work of Hutton in Scotland, Cuvier in France, and William Smith in England, the much greater--the inconceivably great--antiquity of the earth and the origin of its present forms, by gradual changes which are still going on, was generally acknowledged. Indeed, as already said, this is the fundamental idea of geology, without which it could not exist as a science.

Geology has its own measures of time--in eras, periods, epochs, ages, etc.--but it is natural and right that we should desire more accurate estimates by familiar standards. How old, then, is the earth, especially the inhabited earth, in years? Geologists have attempted to answer this question by estimates based on the rates of sedimentation and erosion, or else on the rate of changes of organic forms by struggle for life and survival of the fittest. Physicists have attempted to answer the same question by calculations based on known laws of dissipation of energy in a cooling body, such as the sun or the earth. The results of the two methods differ widely. The estimates of the geologists are enormous, and growing ever greater as the conditions of the problem are better understood. Nothing less than several hundred million years will serve his purpose. The estimates of the physicists are much more moderate, and apparently growing less with each revision. The latest results of King and Kelvin give only twenty to thirty millions.[2] This the geologist declares is absurdly inadequate. He can not work freely in so narrow a space--he has not elbow room.

The subject is still discussed very earnestly, but with little hope of definite conclusion. One thing, however, must be remarked. Both parties assume--the geologist tacitly, the physicist avowedly--the nebular hypothesis of the origin of the solar system, and therefore the early incandescent _fluid_ condition of the earth as the basis of all his reasonings. Now, while this is probably the most reasonable view, it is not so certain that it can be made the basis of complex mathematical calculation. There is a possible alternative theory--viz., the meteoric theory--which is coming more and more into favor. According to this view, the planets may have been formed by aggregation of meteoric swarms, and the heat of the earth produced by the collision of the meteors in the act of aggregation. According to the one view (the nebular), the heat is all primal, and the earth has been only losing heat all the time. According to the other, the aggregation and the heating are both gradual, and may have continued even since the earth was inhabited. According to the one, the spendthrift earth wasted nearly all its energy before it became habitable or even a crust was formed, and therefore the habitable period must be comparatively short. According to the other, the cooling and the heating, the expenditure and the income, were going on at the same time, and therefore the process may have lasted much longer.

The subject is much too complex to be discussed here. Suffice it to say that on this latter view not only the age of the earth, but many other fundamental problems of dynamical geology, would have to be recalculated. The solution of these great questions must also be left to the next century. In the meantime we simply draw attention to two very recent papers on the subject--viz., that of Lord Kelvin,[3] and criticism of the same by Chamberlin.[4]

ANTIQUITY AND ORIGIN OF MAN.

Even after the great antiquity of the earth and its origin and development by a natural process were generally accepted, still man was believed, even by the most competent geologists, to have appeared only a few thousand years ago. The change from this old view took place in the last half of the present century--viz., about 1859--and, coming almost simultaneously with the publication of Darwin's Origin of Species, prepared the scientific mind for entertaining, at least, the idea of man's origin by a natural process of evolution.

Evidences of the work of man--flint implements, associated with the bones of extinct animals and therefore showing much greater age than usually accepted--had been reported from time to time, notably those found in the river Somme by Boucher de Perthes. But the prejudice against such antiquity was so strong that geologists with one accord, and without examination, pooh-poohed all such evidence as incredible. It was Sir Joseph Prestwich who, in 1859, first examined them carefully, and published the proofs that convinced the geological world that early man was indeed contemporaneous with the extinct animals of the Quaternary period, and that the time must have been many times greater than usually allowed.[5]

Since that time confirmatory evidence has accumulated, and the earliest appearance of man has been pushed back first to the late glacial, then to the middle glacial, and finally, in Mr. Prestwich's Plateau Gravels, to the early glacial or possibly preglacial times.

Still, however, in every case earliest man was unmistakably man. No links connecting him with other anthropoids had been found. Very recently, however, have been found, by Du Bois, in Java, the skull, teeth, and thigh bone of what seems to be a veritable _missing_ link, named by the discoverer _Pithecanthropus erectus_. The only question that seems to remain is whether it should be regarded as an ape more manlike than any known ape, or a man more apelike than any yet discovered. The age of this creature was either latest Pliocene or earliest Quaternary.

BREAKS IN THE GEOLOGICAL RECORD AND THEIR SIGNIFICANCE.

From the earliest times of geologic study there have been observed unconformities of the strata and corresponding changes in the fossil contents. Some of these unconformities are local and the changes of organic forms inconsiderable, but sometimes they are of wider extent and the changes of life system greater. In some cases the unconformity is universal or nearly so, and in such cases we find a complete and apparently sudden change in the fossil contents. It was these universal breaks that gave rise to the belief in the occurrence of violent catastrophes and corresponding wholesale exterminations and re-creations of faunas and floras.

It is evident, however, on a little reflection, that every such unconformity indicates a land period at the place observed, and therefore a time unrecorded in strata and fossils at that place--i. e., a lost interval--certain leaves missing from the book of time. And if the unconformity be widespread, the lost interval is correspondingly great. It is therefore probable that change of species went on slowly and uniformly all the time, although not recorded at that place. Intermediate strata may be and often are found elsewhere, and the supposed lost interval filled. The record was continuous and the changes uniform, but the record is not all found in one place. The leaves of the book of Time are scattered here and there, and it is the duty of the geologist to gather and arrange them in proper order, so that the record may read continuously.

This is the uniformitarian view, and is undoubtedly far truer than the catastrophic. But the objection to it is that in the case of very widespread unconformities, such as occurred several times in the history of the earth, the changes of organisms are so great that if the rate of change was uniform the lost interval must have been equal to all the rest of the history put together. Therefore we are compelled to admit that in the history of the earth there have been periods of comparative quiet (not fixedness) during which evolutionary changes were slow and regular, and periods of revolution during which the changes were much more rapid, but not catastrophic. This is exactly what we ought to expect on the idea of gradual evolution of earth forms by secular cooling, for in the gradual contraction of the earth there must come times of general readjustment of the crust to the shrinking nucleus. These readjustments would cause great changes in physical geography and climate, and corresponding rapid changes in organic forms. In addition to this, the changes in physical geography and climate would cause extensive migrations of species, and therefore minglings of faunas and floras, severer struggles of competing forms, and more rapid advance in the steps of evolution. Among these changes of organic forms there would arise and have arisen _new dominant types_, and these, in their turn, would compel new adjustment of relations and still further hasten the steps of evolution. Such changes, whether geographic, or climatic, or organic, would _not_ be simultaneous all over the earth, but propagated from place to place, until quiet was re-established and a new period of comparative stability and prosperity commenced.

This view is a complete reconciliation of catastrophism and uniformitarianism, and is far more rational than either extreme.

_Critical Periods in the History of the Earth._--Such periods of rapid change may well be called _critical periods or revolutions_. They are marked by several characteristics: (1) By widespread oscillations of the earth's crust, and therefore by almost universal unconformities. (2) By widespread changes of physical geography, and therefore by great changes in climate. (3) By great and widespread changes in organic forms, produced partly by the physical changes and partly by the extensive migrations. (4) By the evolution of new dominant types, which are also the cause of extensive changes in species. (5) Among the physical changes occurring at these times is the formation of great mountain ranges. The names of these critical periods or revolutions are often taken from the mountain range which form their most conspicuous features.

There have been at least four of these critical periods, or periods of greatest change: (1) The pre-Cambrian or Laurentide revolution; (2) the post-Paleozoic or Appalachian; (3) the post-Cretaceous or Rocky Mountain; (4) the post-Tertiary or glacial revolution.

Now, as these critical periods separate the primary divisions of time--the eras--it follows that the _Present_--the Age of Man--is an era. It may be called the _Psychozoic Era_. These views have been mainly advocated by the writer of this sketch, but I believe that, with perhaps some modification in statement, they would be accepted by most geologists as a permanent acquisition of science.[6]

GEOLOGICAL CLIMATES.

Attention was first drawn to this subject by the apparently unique phenomena of the Glacial epoch.

For nearly a century past Alpine glaciers, their structure, their mysterious motion, and their characteristic erosive effects, have excited the keenest interest of scientific men. But until about 1840 the interest was purely physical. It was Louis Agassiz who first recognized ice as a great _geological agent_. He had long been familiar with the characteristic marks of glacial action, and with the fact that Alpine glaciers were far more extensive formerly than now, and had, moreover, conceived the idea of a Glacial epoch--an ice age in the history of the earth. With this idea in his mind, in 1840 he visited England, and found the marks of glaciers all over the higher regions of England and Scotland. He boldly announced that the whole of northern Europe was once covered with a universal ice sheet. A few years later he came to the United States, and found the tracks of glaciers everywhere, and again astonished the world by asserting that the whole northern part of the North American continent was modeled by a moving ice sheet. This idea has been confirmed by all subsequent investigation, especially here in America.

But it would be strange, indeed, if the cold of the Glacial epoch should be absolutely unique. Attention was soon called to similar marks in rocks of other geological periods, especially in the Permian of the southern hemisphere. This opened up the general question of _geological climates and their causes_.

Perhaps no subject connected with the physics of the earth is more obscure and difficult than this. The facts, as far as we know them, are briefly as follows: (1) All the evidence we have point to a high, even an ultra-tropical, climate in early geological times; (2) all the evidence points to a uniform distribution of this early high temperature, so that the zonal arrangement of temperatures, such as characterizes present climates, did not then exist; (3) temperature zones were apparently first introduced in the late Mesozoic (Cretaceous) or early Tertiary times, and during the Tertiary the colder zones were successively added, until at the end there was formed a polar ice-cap as now.

Thus far all might be explained by progressive cooling of the earth and progressive clearing of the atmosphere of its excess CO_[2] and aqueous vapor. But (4) from time to time (i. e., at critical periods) there occurred great oscillations of temperature, the last and probably the greatest of these being the Glacial period. The cause of these great oscillations of temperature, and especially the cause of the glacial climate, is one of the most interesting and yet one of the obscurest and therefore one of most hotly disputed points in geology. Indeed, the subject has entered into the region of almost profitless discussion. We must wait for further light and for another century. Only one remark seems called for here. It is in accordance with a true scientific method that we should exhaust terrestrial causes before we resort to cosmical. The most usual terrestrial cause invoked is the oscillation of the earth's crust. But recently Chamberlin, in a most suggestive paper,[7] has invoked oscillations in the composition of the atmosphere, especially in its proportion of CO_[2], as the _immediate_ cause, although this in turn is due to oscillations of the earth's crust.

THE NEW GEOLOGY.

Heretofore the geological history of the earth has been studied only in the record of stratified rocks and their contained fossils. But in every place there have been land-periods in which, of course, erosion took the place of sedimentation. This kind of record is very imperfect, because there are no fossils. Until recently no account was taken of these erosion-periods except as breaks of indefinite length in the record--as lost intervals. But now, and mainly through the work of American geologists, interpretation of these erosion-periods has fairly commenced, and so important has this new departure in the study of geology seemed to some that it has been hailed as a new era in geology, connecting it more closely with geography. Heretofore _former_ land periods were recognized by unconformities and the amount of time by the degree of change in the fossils, but now the amount of time is estimated in _existing_ land surfaces by topographic _forms_ alone. This idea was introduced into geology by Major J. W. Powell, and has been applied with success by William Morris Davis, W. J. McGee, and others.

The principle is this: Land surface subject to erosion and standing still is finally cut down to gently sweeping curves, with low, rounded divides and broad, shallow troughs. Such a surface is called by Davis a Peneplain. Such a peneplain is characteristic of old topography. If such a surface be again lifted to higher level, the rivers again dissect it by ravines, which are deep and narrow in proportion to the amount and rate of the uplift. If the land again remains steady, the sharply dissected surface is again slowly smoothed out to the gentle curves of a peneplain. If, on the contrary, the surface be depressed, the rivers fill up the channels with sediment which, on re-elevation, is again dissected. Thus the whole _ontogeny_ of land surfaces have been studied out, so that their age may be recognized at sight.

Thus, while heretofore the more recent movements of the crust were supposed to be readable only on coast lines and by means of the old sea strands, now we read with equal ease the movements of the interior by means of the physiognomy of the topography, and especially the structure of the river channels. Moreover, while heretofore the history of the earth was supposed to be recorded only in stratified rock and their contained fossils, now we find that recent history is recorded and may be read also in the general topography of the land surfaces. Geography is studied no longer as mere description of earth forms, but also as to the causes of these forms, no longer as to present forms, but also as to the history of their becoming. Thus geography, by its alliance with geology, has become a truly scientific study, and as such is now introduced into the colleges and universities. It is this alliance with geology which has caused the dry bones of geographic facts to live. It is this which has created a soul under the dry "_ribs of this death_." This mode of study of the history of the earth has just commenced. How much will come of it is yet to be shown in the next century.

In this connection it is interesting to trace the effect of environment on geological reasonings in different countries. Heretofore, especially in England, what we have called peneplains were usually attributed to marine denudation--i. e., to cutting back of a coast line by constant action of the waves, leaving behind a level submarine plateau, which is afterward raised above sea level and dissected by rivers. American geologists, on the contrary, are apt to regard such level surfaces as the final result of aërial degradation or a base level of rain and river erosion. The same difference is seen in the interpretation of glacial phenomena. Until recently, English geologists were inclined to attribute more to iceberg, Americans more to land ice. Again, in England coast scenery is apt to be attributed mainly to the ravages of the sea, while in America we attribute more to land erosion combined with subsidence of the coast line. In a word, in the tight little sea-girt island of Great Britain, where the ravages of the sea are yearly making such serious inroads upon the area of the land, it is natural that the power of the sea should strongly affect the imagination and impress itself on geological theories, and tend perhaps to exaggeration of sea agencies, while the broad features of the American continent and the evidences of prodigious erosion in comparatively recent geological time tend to the exaggeration of erosive agency of rain and rivers. These two must be duly weighed and each given its right proportion in the work of earth sculpture.

PALEONTOLOGY.

Paleontology at first attracted attention mainly by the new and strange life forms which it revealed. It is the interest of a zoölogical garden. This interest is of course perennial, but can hardly be called scientific. Geology at first was a kind of wonder book.

Next fossils, especially marine shells, were studied as characteristic forms denoting strata of a particular age. They were coins by which we identify certain periods of history. They were "medals of creation." It was in this way chiefly that William Smith, the founder of English stratigraphic geology, used them. It was in this way that Lyell and all the older geologists, until the advent of evolution, were chiefly interested in them.

It was Cuvier, the great zoölogist and comparative anatomist, who, in the beginning of the present century, first studied fossils, especially mammalian fossils, from the _zoölogical_ point of view--i. e., as to their affinities with existing animals. Cuvier's studies of the vertebrates of the Paris basin may be said to have laid the foundation of scientific paleontology from this point of view.

Thenceforward two views of paleontology and two modes of study gradually differentiated from one another, the one zoölogical, the other geological. In the one case we study fossils in _taxonomic_ groups--i. e., as species, genera, families, orders, etc.--and trace the gradual evolution of each of these from generalized forms to their specialized outcomes, completing as far as possible the genetic chain through all time. In the other we study fossils in _faunal groups_, as successive geological faunas, and the geographic diversity in each geological period--i. e., the evolution of geologic faunas and the causes of geographic diversity in each. In a word, we study the laws of distribution of faunas in time geologically and in space geographically, and the causes of these laws in each case. The first is strictly a branch of zoölogy and botany, and we leave it to these specialists. The second alone belongs properly to geology. In this purely geologic paleontology, as seen from its scope given above, there are many questions of widest philosophical interest which are only now attracting the attention they deserve. I only touch lightly two which have been brought forward in these very last years of the century.