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account for any quite modern peculiar- which at the beginning of that period ity of distribution. He refuses to had winter in perihelion at the end has bridge over the Pacific merely in order it in aphelion. At the present moment to explain the presence of tapirs in Su- this cause probably accounts in great matra and in Brazil ; he demurs to the part for the difference between the cliinvention of a lost Lemuria between mate of the two hemispheres ; for the Madagascar and the Deccan, simply be- north has now a somewhat shorter and cause some South Indian species resem- warmer winter than the south. But the ble some Madagascar types; and he eccentricity of the earth's orbit itself also will not consent to manufacture a road varies largely and irregularly, though from New Zealand to the Cape and to very slowly; and it is calculated that South America, for no better reason when the eccentricity is highest the difthan because struthious birds are found erences in temperature brought about in at the present day in all three of them, either hemisphere by the cycle in quesand in no intermediate region. His tion would be very much intensified. wide grasp of facts, geological, palæonto- Dr. Croll points out that such a period logical, and biological, enables him to of high eccentricity began about 250,000 frame hypotheses which are less simple, years ago, and reached its maximum it is true, but which have the merit of 210,000 years ago. He believes that explaining all the facts instead of being the last glacial epoch, which formed the contradicted by nine tenths of them. ice-worn boulders and moraines of our He knows that ancestral tapirs once Welsh and English hills, began at this ranged in every country from Sumatra period of high eccentricity, and continto Paris, and from Paris to North Amer- ued intermittently in either hemisphere ica ; that ancestral ostriches swam about with each cycle of 10,500 years down to in the Western States or roamed over some 80,000 years since, warm interglathe plains of England ; and that we can cial periods occupying the intervals. more easily explain the similarities of This theory has been pretty generally Indian and Madagascar species by other accepted by all scientific men. But Dr. known principles than by such a clumsy Croll also believes that similar glacial and false expedient as that of a Le- periods have probably occurred with muria, whose fauna is not to be found each irregular period of high eccentricin any of its supposed existing frag- ity. He even points out the probability ments, Bourbon and Mauritius.
that an ice age, far more severe than that Passing on to the problem of geologi- with whose remains we are so familiar, cal climates, so closely connected with occurred about 850,000 years ago, and the distribution and dispersal of plants coincided with some part of the Mioand animals, Mr. Wallace arrives at con- cene period. To this latter portion of clusions which are, perhaps, somewhat Dr. Croll's argument Mr. Wallace demore doubtful, certainly more opposed murs. Accepting the general theory to received opinions, yet which seem con- that the last glacial epoch was due in clusively reasoned out. It has for some the main to a period of high eccentrictime been acknowledged that certain re- ity, he denies that every such period curring astronomical conditions of our necessarily produces an ice age. planet help us largely to account for Mere astronomical changes are not in those great changes of climate which we themselves sufficient to account for the know to have often occurred in geologi- climatic peculiarities of glacial epochs. .cal time ; and it has usually been held Mr. Wallace shows that glaciation can as a corollary to this opinion, that gla- only take place when the circumstances cial epochs in the northern and southern allow large accumulations of ice and hemispheres respectively must recur at snow. Such accumulations require high certain fixed though irregular periods. land at or near the poles. He then exDr. Croll has pointed out that a partic- amines the tertiary formations of Euular combination of astronomical revolu- rope, and points out that they contain tions, the precession of the equinoxes no large deposits of presumably glacial and the motion of the aphelion-brings origin, but that, on the contrary, they about a change of position in a cycle of involve almost without exception the 10,500 years, so that the hemisphere prevalence of a comparatively warm and
almost tropical climate throughout the sea, and are, therefore, mere fragments whole long period in which they were de- of those which exist in the nearest mainposited. The Arctic flora of tertiary land. Birds and flying insects form their and secondary times was also of a tem- chief animal inhabitants, because they perate character. Putting all the evi- can be carried out to sea for long disdence together; he urges that since the tances on their own wings during heavy Permian period, at least, the climate of gales. Land snails, borne in the egg or Northern Europe and America was unin- in crevices of wood, are also common. terruptedly warm (up to the last ice age), On the other hand, mammals and amwhile that of the Arctic regions was phibia are wholly wanting. Plants, comparatively mild. The last glacial whose seeds or spores can be readily epoch he believes to have been an ex- borne by wind or waves, are comparaceptional phenomenon, due to the rise tively abundant. The degree of local of much high land about the pole, coin- modification which the species have uncidently with the coming on of a period dergone in their new homes depends of high eccentricity. On the other hand, mainly on three conditions--the length the warm Arctic climates which prevail- of time during which the islands have exed throughout the secondary and terti- isted; the frequency of fresh arrivals to ary ages, he attributes to the existence of keep up the purity of the old types ; an open polar sea, with currents of hot and the peculiarities of the surface and water setting toward it from the equa- other productions, reacting upon the torial oceans. If this view be true-and various species. it is enforced by all that wide and mi- In the Azores we have an instance of nute knowledge of facts in every depart- an oceanic archipelago, where most spement of science which is Mr. Wallace's cies have remained fairly true to their speciality -we must in future regard original continental forms. Lying about geographical conditions as far more im- nine hundred miles west of the Portuportant than astronomical in producing guese coast, they possess an indigenous alterations of climate. The alternate fauna of wholly European character, warm and cold spells supposed of neces- only slightly modified in a few unimsity to accompany periods of high ec- portant particulars. It consists of centricity need now only be expected in birds, insects, and land shells. Most of cases where special features of polar ge- the birds are waders or swimmers ; of ography synchronize with unusual dis- the remainder, all but three are common tance from the sun in winter.
European and North African species. In the second half of Mr. Wallace's Two out of the three exceptions belong work, the general principles of biologi- to Madeira and the Canaries; while cal distribution are particularly applied one, the Azorean bullfinch, is peculiar to the special case of islands, which al- to the islands. Thus, a single bird low of detailed treatment impossible in alone has varied enough from its anceswider stretches of land. Islands may tral type to be considered as a separate be grouped in two great classes, oceanic species. The reason for this relative and continental. The former are those fixity of type is that the Azores lie in which have never at any time formed the belt of storms, and that stragglers part of any continent, and which, there- from Europe arrive in the islands almost fore possess no indigenous terrestrial every season. The one species which mammals. The latter are those which has varied is the bullfinch, which does have once been united with the adjacent not migrate, and is, therefore, less likely mainland, and which, therefore, possess to be blown out to sea. Among the inthe same general type of fauna and sects, the butterflies are almost all Euroflora, more or less profoundly modified pean ; but twenty-three beetles out of by local conditions in rough proportion iwo hundred and twelve are peculiar to to the length of time during which they the islands, while a few others belong by have been isolated.
origin or affinities to South America, to Oceanic islands are of volcanic or cor- the Canaries, and even to Madagascar. alline formation, and contain few or no As beetles must be reinforced by fresh old sedimentary deposits. Their fauna individuals of their own species far less and flora have been wafted to them over frequently than birds or butterflies, the
greater divergence among them is per- possess at least some terrestrial mamfectly natural. Lastly, land snails, mals. Recent continental islands, like which have least power of dispersal of Great Britain, are situated on submerged all, show the largest amount of local banks, connecting them with the mainpeculiarity, nearly half being found in land: they resemble the continent in no other place. The Bermudas stand their geological structure ; while their to America in much the same relation fauna and flora are identical with those as the Azores to Europe, and their fauna of the neighboring mainland, or differ and flora display almost exactly analo- very slightly from them. Our own gous features. Lying two hundred miles country forms, perhaps, the best ex
the mainland, however, the ample of this class. It possesses a modchances of stray birds arriving from time est mammalian fauna, identical with that to time are even greater than in the of northern Europe, as far as it goes, but Azores ; and so all the birds without ex- much poorer ; while in reptiles and amception belong to American species. phibia it is even more deficient. One The insects, too, remain true to type ; of our birds, however, the red grouse, is but there are four peculiar snails and decidedly peculiar; and two other varitwo ferns which have sufficiently altered eties, the coal-tit and long-tailed tit, are to rank as separate kinds. These two sufficiently different to be ranked by insular groups are examples of recent competent authorities as separate speoceanic islands, only just beginning to cies. Among fresh-water fish we have possess a peculiar fauna and flora of no less than fifteen kinds peculiar to their own, and prevented from doing so Britain ; and some of these have very more rapidly (if at all) by the great restricted areas, being only found in one tacilities which exist for intercourse from or two Scotch or Irish mountain lakes. the continent.
This strong tendency to local variation The Galapagos Islands stand nearer is due to the difficulty or impossibility to South America than do either of the of intercourse between the inhabitants previous groups to their nearest main- of one tarn and another. A good many land. But they are probably of older insects are held to be more or less speformation, and they lie within the storm- cifically British, and there are certainly less equatorial belt. Hence their fauna
a great number of marked varieties. and flora are far more peculiar. There These incipient differences are most are two large tortoises, derived from noticeable in the outlying islands, such America, but now quite distinct from as the Isle of Man and the Shetlands. any American kind; and five lizards, Among the mollusca, Ireland has a slug three of which differ specifically from and a snail found nowhere else. Altotheir ancestors, while two have so far gether, Mr. Wallace shows by a most exdiverged as to be accounted separate ħaustive survey of the British fauna, genera. Among the birds, we find every that though it is still in the main identigradation of difference, froin those cal with that of the continent, a considwhich are perfectly identical with con- erable amount of variation already extinental species, to those which have ists, and shows itself most markedly in varied widely enough to be classed as the most isolated situations, or among generically distinct; and this diversity the most scattered groups of organisms. bears an obvious relation to the facilities Borneo and Java, though perhaps no which each original species possesses for older than Britan, display the same migration to the islands. The insects peculiarities even more distinctly, owing und land-shells are mostly peculiar; in part to the greater richness of tropiwhile a still larger number of the plants cal life, but still more, no doubt, to their have adapted themselves to their new wider separation from the adjacent consituation, sometimes out of all knowl- tinent. edge of their ancestors.
Perhaps the most wonderful specimen Continental islands differ in several of ingenious reasoning in the whole book important respects from those of oceanic is contained in the singularly clever and origin. They are more varied in geo- intricate chapters on New Zealand, logical features, containing ancient and classed with Celebes among anomalous modern stratified rocks, and they always islands. The fauna and Rora of New
Zealand have long formed an insoluble cious relations to that of Australia, many crux for the geographical biologist ; and families being common to both, while Mr. Wallace's explanation, though it others are unaccountably absent. perhaps makes rather large demands accountably, that is to say, before Mr. upon our powers of assent, has at least Wallace's ingenious solution had been the merit of perfectly harmonizing all offered ; for if he is right, the common the facts. Whether the series of families and genera are those of the old changes which he supposes to have taken tropical Australia, altered and modified place are actually those which did take of course by change of circumstances ; place or not, it is at any rate certain while the families and genera found in that such changes would have resulted Australia but not in New Zealand are in the state of things which we do as a those of the separate western temperate matter of fact now find existing. It island. So that now temperate New would be inipossible adequately to sum- Zealand has relationships not with the marise his arguments without employing temperate but with the tropical portion many pages ; but the gist of his actual of the Australian plant-life. conclusions is this :
So much is sufficient to account for During the Cretaceous period, Aus- the main peculiarities of the New Zeatralia was divided into two large islands, land flora; but other facts are implied one of which, the western, was temper- by its fauna. The large number of ate in climate, and almost as extensive wingless birds, extinct or living, in so as the existing continent. The other or small a country, calls for special explaeastern island was a long and narrow nation. Fifteen species of apteryx and strip of land, extending from Cape York moa have within recent times inhabited on the north to a point beyond modern New Zealand. Hence we must suppose Tasmania on the south, and so stretch- that when the ancestral form of these ing from the tropics into the heart of wingless birds first established itself in the ternperate zone. Between these two the island its area must have been far islands lay a sea, in whose bed cretace- larger than at the present day. Again, ous and tertiary deposits are now found the large island thus postulated must uniting the two halves of the continent. have split up at a later period into From New Zealand, a long submarine several smaller but still considerable spur or bridge runs northwestward tow- islands, on each of which a local species ard Cape York. At some time or of moa or apteryx was developed. Then other a land connection must have exist- once more the various islands must have ed along this spur, by its temporary ele- been reunited by an elevation of the vation above the sea level. But this great submarine bank which still probconnection was only with tropical east- ably marks their sites ; and the various ern Australia, while between New Zea- local species must thus have spread land and temperate Australia a deep sea themselves over the whole area. Lastly, channel has always lain. In this man- the larger part of this new land must ner those Australian plants and animals afterward have subsided again, leaving which already inhabited the tropical por- all the species crowded together in the tion of the eastern island were enabled comparatively narrow space of the existto invade New Zealand ; but those ing New Zealand. Thus, by the combiwhich inhabited the western island were nation of various facts, botanical, zounable to do so, unless they had already ological, geological, and geographical, established themselves at an earlier which he knows so well how to co-ordiperiod by stray accidents in the sister nate, Mr. Wallace evolves order from land. At an epoch subsequent to the the chaos of various isolated observare-insulation of New Zealand, the two tions, and builds up for us a complete Australias became united by the up- history of New Zealand and the surheaval of the cretaceous and tertiary rounding lands, every one of whose items sea-bottom, and the faunas and Aoras of is a masterpiece of connected reasoning. both halves were enabled freely to min. Even if we allow that the whole result is gle with one another. Accordingly, at perhaps too hypothetical for implicit the present time, the fora of New Zea- acceptance, we must at least recognize land presents the most apparently capri- the wonderful skill with which the evidence has been pieced together, and the minute and painstaking scrutiny of facts. reconstiuctive power by which it has He takes his subject-matter from all the been made 10 yield a consistent and sciences, and he builds it into a new and probable story. If we are not certain harinonious whole Every page is interthat Mr. Wallace's account is exactly esting merely in virtue of the special what took place, we may at any rate facts which it details ; but the entire feel sure that it is very near the actual work is a thousand times more interesttruth.
ing in virtue of the consistent thread of As a whole, “ Island Life" is almost reasoning which runs through it, and of above criticism. Mr. Wallace brings to the general light which it throws upon his task a rare combination of qualities the whole course of organic evolution, not usually compatible with one another and the whole physical history of our -the faculty for wide and far-seeing planet. - Fortnightly Review. generalizations, and the faculty for
A VISIT TO THE OLDEST STATE IN EUROPE,
BY J. THEODORE BENT.
That the smallest and the oldest of and one longs to people the solitary European governments should be com- mountain which occupies almost the bined in one is in itself a curious fact; whole of the Republic with dwarfs and that this government should be ingulfed, beings of another world. Strange to so to speak, in the middle of Italy, with say, in Roman days this mountain was principalities, ducbies, and kingdoms known as the “ Titanic rock"; here, whirling around it like leaves driven by among the upheaval of strata and yawna winter's storm, adds force to this po- ing chasms of tufa, the ancients conjured litical phenomenon ; but that so little is up a race of giants, ambitious in their known and so little veneration paid to greatness to overthrow the King of this Methuselah among states is perhaps Heaven ; while now we find existing on the most extraordinary feature in its ex- this very spot the most pigmy of states. istence among us in the nineteenth cen- As the scene of a fairy tale San Marino tury.
would offer the facilities of a BrobdingFor this is a community whose au- nag and a Liliput all in one. thentic history dates from the days Curiosity led me to this mountain Reof Pepin, father of Charlemagne, and public, curiosity led me to examine its whose legendary history carries us back history and its constitution, and my to the days when the persecutions of the curiosity was rewarded by the discovery Roman Emperor Diocletian drove a of a unique instance of mediæval statepious anchorite to the mountains in the craft, the sole survivor of the countless neighborhood of Rimini, there to form republics which once dotted Italy, still a semi-ecclesiastical community, which governed by institutions which were still retains its primitive simplicity both hoary with age when Cæsar Borgia enin constitution and customs.
deavored to add it to his dominions, and San Marino is the name of this Lili- which Napoleon the Great respected and putian state ; it has a population of Garibaldi treated with decorum. Let eight thousand souls, an area of sixteen those who feel disposed visit with me square miles ; it is governed by two this tiny state and discuss its peculiariCaptains, it has Secretaries of State for ties, only alluding to its constitution and home and foreign affairs, and above all history with Napoleonic respect when it has a most exemplary Chancellor of occasion may require. its limited Exchequer, who has invari- After a drive of a few hours from ably an annual balance to place at his Rimini our vetturino made us aware that country's disposition.
we were crossing the frontier of the ReHere, indeed, is a field for a modern public, where the road which leads to Gulliver ; the whole atmosphere of the the little commercial village at the foot place is, politically speaking, Liliputian, of the Titanic rock traversed a stream