last glaciation, say no more than some eighty thousand years ago. The whole north had gone solid for ice. The crystal sheet that covered the surface of the entire continent, as far south as Baltimore and Washington, must at the time of its greatest extension have had a thickness of which the puny modern coating of Greenland and the Antarctic land-those last relics of the old polar caps can scarcely give us any adequate conception. The ice lay so deep and high that it ground smooth the summits of the Catskills, three thousand feet above the Hudson Valley; and the scratches and polishing due to its ceaseless motion may be still observed among the White Mountains of New Hampshire, at a height of 5,500 feet above sea-level. A hundred yards higher still, the glacial mud lies even now upon the upper slopes and combes of Mount Washington. We may probably conclude. therefore, that the ice at its thickest rose to at least some six thousand feet above the general level of the North American plainlands. And this vast moving continent of solid glacier pressed slowly and surely, ever downward, from the Arctic regions to its fixed melting-point in the latitude of Maryland. As it went, it wore down the eternal hills like hummocks in its march, and filled the intermediate troughs with wide sheets of rubbish from their eroded material. The grooves worn in the solid Silurian limestone by the shores of Lake Ontario look in places like big rounded channels, and in their regularity and parallel arrangement, always running approximately from north to south, closely simulate some gigantic product of human workmanship. In places the rock seems almost to undulate, as if upheaved and disturbed from below by some long rolling wave-like convulsion.

All northern America, as we see it today, is the natural result of this terrific orgy of profound glaciation. The great continent always does things on the big scale; and when the ice set to work to ruin the smiling fields of the genial Pliocene period, it ruined them in good earnest, as if it really meant it. From the Atlantic to the foot of the Rocky Mountains, and from the latitude of Maryland up to the eternal snows, all

America still suffers visibly to the naked eye from the havoc wrought by that long and widespread secular calamity. The mountains, to be sure, have slowly weathered down in process of time, and vegetation has spread tentatively among the rifts and ravines excavated on their flanks; but in most places even now where there are still or once were mountains, the greater part of the land remains as mere shining flats of polished rock, naked and not ashamed, or barely covered with a girdle of foliage strewn here and there upon its rugged loins. The moraines and drift still occupy the better part of the intervening spaces; and though the native vegetation here grows thicker and lusher, the cultivated fields attest abundantly, by their frequent heaps of picked-out boulders, with what ceaseless toil in these stony basins tillage has been brought up at last to its present low and shabby level. It is only in a few rare spots by the river sides, in the Eastern States at least, that any depth of alluvial soil, spread over the surface by floods since glacial times, gives rise to meadows of deep grass, or to cornfields which approach, at a dismal distance, our European standard of good farming. I speak, of course, of . the East alone. In the West, the profounder alluvium of the great central basin has had time to collect from the Mississippi and Missouri tributaries, over the vast areas which form the American and Canadian wheat-belt.

It is the Great Ice Age, too, that is mainly answerable for the very inconvenient and awkward distances between American cities. For eastward but few spots exist, and those mainly along the river valleys, that lend themselves readily to human tillage. The greater part even of old-settled Massachusetts remains to this day under primeval forest, and will probably remain so, at least as long as an acre of wheat-land continues unoccupied in the unencumbered plains of the Western grain-belt. Immense areas in the Eastern States are naturally far more unfit for agricultural use than any part of Wales or the Scotch Highlands. The only district of Britain, indeed, that can give the faintest idea of such unconquerable barrenness may be found in the slopes of the Llawllech range, that stretches at the back of Har


lech and Barmouth. Hence it happens that the population in Eastern America concentrates itself entirely around a few great Atlantic commercial emporiumsNew York, Boston, Philadelphia, Baltimore; straggles somewhat more sparsely up the agricultural valleys of the Hudson, the Connecticut, the St. Lawrence or the Ottawa; and leaves the vast ridges of intervening highland or low ice-worn plateau in almost untouched and primitive wildness. Eastern America consists, in short, of some few solitary islets of civilization, sprinkled at long distances through a great sea of serried forest and uncultivable woodland. In the West, once more, things are very different; there, a marvellous network of railways through the flat central basin, interlacing and looping at every point, shows at once on the map potentialities for the future support of a teeming population.

On the other hand, while America has suffered immensely in her geographical and agricultural features from the Great Ice Age, she has suffered far less in her fauna and flora than poor peninsular and isolated Europe. For us, the Glacial epoch was a final catastrophe-the end of most things; for America it was merely an unfortunate episode. The second thing that strikes an English naturalist in New England, after he has got accustomed to the first flush of the allpervading glacial phenomena, is the wonderful proportional richness of the vegetation and the animal life. In Europe, and still more in England, we have only a bare score of indigenous mammals, only half a dozen or so of indigenous forest-trees-oaks and elms, ashes and maples, birches and beeches, pines and lime-trees. But in the American woods the wild beasts are large and numerous, the birds are multitudinous and multiform, the insects are innumerable, the names of the various foresttrees are legion. Scarcely any two one sees at the same moment are of the same species; and the diversity and beauty which this variety gives to the trunks and foliage forms one great charm of wild American woodland scenery. Life with us is poor and stunted; life in America is rich and manifold and vigorous and beautiful.

Asa Gray has well pointed out the un-

derlying reason for this marked difference between the plants and animals of the two continents. On our side all the main mountain ranges-Pyrenees and Asturias, Alps and Carpathians, Balkans and Caucasus-trend ever regularly east and west, along the axis of the great subdivided peninsula of Europe. In America the two main mountain systems, the Rockies and the Alleghanies, with all their outliers and lateral ranges, trend ever regularly north and south, along the axis of the big, solid, undivided continent. Furthermore, Europe is sharply cut off from the south by the Mediterranean, and again just beyond the Atlas chain by the vast lifeless area of Sahara. When the enormous icesheet of the glacial epoch began to form, it covered the northern half of our continent with its devastating mass, and chilled the frosty air of the remainder as far south as the Mediterranean. Even Spain and Italy must then have possessed a climate far more rigorous and forbidding than the climate of Labrador in our own day. Nor was this all; the Alps and the Apennines, the Sierras and the Carpathians, were each the centres of minor ice-sheets, of which a few shrunken representatives still remain in the Mer de Glace and along the flanks of the Pic du Midi. But during the Great Ice Age these mountain glaciers extended far more widely in every direction over the better part of Switzerland and the Tyrol, of Southern France and Northern Italy. As the ice moved slowly ever southward, it pushed the warm Tertiary fauna and flora remorselessly before it, crushing them up and hemming them in between the northern ice-sheet and the Alps, the Alps and the sea, the Sierra and the Straits, the Straits and Sahara. Naturally, in such hard times the warmer types died out entirely, and only those sterner plants and animals which could accommodate themselves to the chilly conditions of the Glacial Period struggled through with bare life somehow into the succeeding epoch of secular summer.

When the ice retreated slowly northward once more, it left behind it a Europe (and a Siberia) out of which all the largest, fiercest, and strongest animals, as well as half the most beautiful trees and shrubs and plants, had been



utterly exterminated. The mammoth and the mastodon were gone forever; the elephant and the rhinoceros were gone too; the tapir and the hipparion, the hyæna and the monkey, the primitive panther and the sabre-toothed lion, all had disappeared from the face of our continent, and some of them utterly from the face of the earth. The European fauna and flora of the Pliocene age-the genial age just preceding the Glacial epoch-were richer and more luxuriant in type than those of sub-tropical South Africa at the present day. Chestnuts and liquidambars, laurels and cinnamons, ancestral tamarinds and Australian hakeas, with conifers like the big trees of the Mariposa grove, had flourished lustily in those happy years by the banks of the Seine. the Rhine, and the Danube. Through such forests of lush sub-tropical vegetation, early man-that dark and low-browed savage whose fire-marked flints the Abbé Bourgeois unearthed from the still earlier deposits of the Calcaire de Beaucemust have chased many wild and ferocious creatures now known to us only by the scanty bones of the Red Crag and the Belvedere-Schotter. The dinotherium, with his fearsome tusks, still basked in the sunshine by the riverbank at Eppelsheim; the hippotherium, with his graceful Arab-like tread, still cantered lightly over the Vienna plains. The African hippopotamus lolled as commonly in the Rhone as in the Nile. Apes and gazelles gambolled over the not yet classic soil of Attica, side by side with a gigantic wild boar, which fantastic science has not unaptly nicknamed Erymanthian, and with an extinct giraffe as huge in proportions as his modern African representative. "The colossal size of many of its forms," as Geikie puts it, "is the characteristic mark of the Pliocene European fauna." But when the limitless ice sheet swept all these gigantic creatures away before it, there was no point from which, on its retreat, they could re-enter the impoverished younger Europe. The Himalayas and the Hindoo Koosh, the Caucasus and the Caspian, Sahara and the Mediterranean, stretched between them one long heterogeneous but continuous barrier, cutting off the surviving fauna and flora of the fortunate south

from the whole depopulated and devastated area of Siberia and Europe.

The consequence is that our modern European fauna and flora are probably the poorest in size and variety to be found anywhere, in an equally large tract of country, over the whole face of the habitable globe. In insular Britain, and more especially in Ireland, this general poverty reaches at length its lowest depth. Even allowing for the extinct species killed off by man within the historical period, what is the miserable little sum-total of our British mammalian population at the very highest period of its recent development? The red deer and the wild white cattle, the bear and the boar, the wolf and the fox, the beaver and the otter, the badger and the weasel, and a beggarly array of smaller wild beasts, such as squirrels, martens, rats, mice, shrews, hedgehogs, hares, rabbits, moles, and water-voles. Even of these, the largest and most interesting forms are gone long since; only the smallest, most vermin-like, and (so to speak) weediest still survive, except under special artificial conditions of deliberate preservation.

In America, on the other hand, when the advancing ice-sheet pushed the genial Pliocene fauna and flora southward before it, it pushed them on, not into the sea, the mountains, or the desert, but into the open lands of Carolina, Kentucky, and the Gulf States. There were no intervening Alps or Pyrenees, between which and the slowly southward marching ice-plain the plants and animals, attacked on front and rear, could be gradually crushed out of earthly existence. So the ice advanced harmlessly to the point where American geologists have of late detected its absolute terminal moraine, in a line running roughly along the parallel of 39° or 40'

about the boundary between the old slave and free States, in fact-and there for a time it halted on its march, leaving the plants and animals it displaced free to find their own quarters in the warmer plains from Florida to Texas, and from the Ohio River to the Gulf of Mexico. The country lay open from the Arctic circle to the tropic in Mexico. As the ice oscillated backward and forward (for the glacial era as a whole embraced, as Dr. Croll and Dr. James Geikie have


proved, from different points of view, many successive glacial and interglacial periods) the vegetation and the wild animals had full freedom to follow it closely northward during each long retreat, and to fall back southward again during each fresh spell of rigid glaciation. As a consequence, the American fauna and flora have not suffered to anything like the same extent as the European from the pauperizing effects of the continental ice-sheet. As soon as the ice got once clear off the face of the ground, trees and shrubs, beasts, birds, and insects, struck north once more, almost in as full force as ever, to occupy the soil their ancestors had left during the first chill that ended the halcyon days of the Pliocene epoch.

No distinct break, therefore, divides the temperate and tropical American life-regions. Europe has no lion, no tiger, no jackal, no crocodile. But the puma (or "panther"), in the native state, ranges from far south of the equator in Paraguay to far north of Hudson's Bay, among the frozen shores of the Saskatchewan and the Athabaska. The coyote, or prairie wolf, is equally at home on the banks of the Missouri and in the North-West Territory. The black and brown bears, it is true, show themselves somewhat more exclusively northern in their tastes; but the grizzly extends, with the utmost impartiality, from the Canadian Rockies as far south as Mexico. The richness of the Canadian fauna in animals like the lynxes, wolverines, ra coons, minks, sables, skunks, badgers, otters, wild cats, and fishers, is very noticeable by the side of our marked European poverty. Flying squirrels, gray squirrels, and other bright little forestine rodents, abound in the woods of the St. Lawrence region. Woodchucks, musquash, and the socalled rabbit are everywhere common. Buffalo roam over the whole prairieland. The moose and wapiti range far northward, till they encroach upon the region of the musk-ox, the caribou, and the polar bear. The great black wareagle, the loon, and the wild duck give life and animation to the woods and lakes. Everywhere one feels oneself in the immediate presence of a large and luxuriant native wild life, to which porcupines and beavers, chipmunk and

gophers, prairie dogs and shrew moles, Virginian deer and prong-horn antelopes, each in its own place, impart variety, novelty, and freshness. One recognizes throughout in America the stamp of a great vigorous continent. Europe, on the contrary, has but the population of a narrow, poverty-stricken, outlying peninsula.

The woods themselves point this obvious moral even more vividly and distinctly than the creatures that inhabit them. American woodland runs riot in its richness. Lissome creepers recall the tangled bush-ropes and lianas of the tropics; a vivid undergrowth of glossy poison-ivy and trailing arbutus and strange shield-leaved or umbrella-shaped may-apple, far surpasses in beauty and luxuriance any temperate forest flora of the eastern hemisphere. Rhododendrons. and kalmias drape the hillsides with masses of pink and purple glory. Virginia creeper crimsons the autumnal treetrunks; the pretty climbing bittersweet, known by that quaint New England name of waxwork, opens its orange pods and displays the scarlet seeds within on every thicket. Wild vines, lithely twisting their supple stems, mantle with rich foliage and with hanging clusters of small bloom-covered grapes the snakefences and wayside bushes by the country roads. Ample leaves like those of the striped maple and of the white basswood impart an almost tropical breadth of shade to the profound recesses of the deeper forests. And to pick the insecteating pitcher-plants among their native bogs, or to watch the strange side-saddle flowers lifting high their lurid blossom among the wicked rosette of uncannylooking, trumpet-shaped leaves, is, to the heart of a naturalist at least, well worth the ten days of volcanic upheaval, external and internal, on the treacherous bosom of the cruel Atlantic.

To compare numerically the larger elements of the landscape alone, we have in Britain three indigenous conifers only-the Scotch fir, the juniper, and the English yew. Against this scanty list Canada proper (the old provinces I mean, not the Dominion) can set, according to Asa Gray, no less than five pines, five firs, a larch, an arbor-vitæ, three junipers, and one yew; that is to say, Canada has fifteen distinct species

of cone-bearing trees to Britain's three. Of catkin-bearers, which form by far the greater and nobler portion of our forest timber, Great Britain has of oak, beech, hazel, hornbeam, and alder one each, with eighteen ill-marked willows and two poplars: twenty-eight species, all told, and some of them dubious. To balance this tale Canada has eight oaks, a chestnut, a beech, two hazels, two hornbeams, six birches, two alders, fourteen willows, five poplars, a plane-tree, two walnuts, and four hickories-fortyeight species, all told. If we remove the willows, badly divided (and, in my private opinion, by no means always distinct), the contrast becomes even more sharply marked. Moreover, as Asa Gray has also pointed out, besides this mere difference in number of species there is, further, a distinct difference in kind and aspect. America has many trees and plants wholly unlike anything European tall arborescent pea-flowers, such as the locusts and cladrastis; southern-looking types, such as magnolia and tulip-tree; bold ornamental shrubs like the rhododendrons and azaleas; handsome composites in immense variety, like the asters, sunflowers, golden-rods, and erigerons. The warm summer climate, in fact, allows many plants and blossoms of tropical luxuriance, like the papaw, the trumpet-creeper, the passion flowers, and the bignonia, to flourish freely in the wild state and in the open air, not only as far north as New York and Philadelphia, but sometimes even on the northern shores of the Great Lakes.


Nevertheless, this superior richness of American life is for the most part demonstrably due to the more favorable set of circumstances for replenishing the earth which existed there at the end of the Great Ice Age. The ancestors of the American wild animals and plants lived also in Europe during the Pliocene period. We had then an American oak of our own; hickories then flourished on the European plains; pines of the western type covered our island hillsides; cotton-woods and balsam poplars, magnolias and tulip-trees, locusts and sugar-maples, grew side by side in French and English copses with our modern elms and oaks and ashes. But the ice swept them all away remorseless

ly on this side of the world, hemmed in as they were between the upper and the nether millstone, the arctic ice-cap and the Alpine glaciers. In America they all returned with the return of warmer weather, and form to this day that beautiful and varied Atlantic woodland which is the delight and the envy of the European botanical visitor.

Before the Glacial epoch the fauna and flora all round the Pole were probably identical. They are practically identical at the present day. But as we move southward differences soon begin to appear between the temperate fauna and flora on either side of the Atlantic, descended though they both are from the more luxuriant circumpolar types of the Pliocene age. The time they have been separated has told distinctly on the formation of species. Hardly any plants or animals now remain absolutely alike on the two continents. Even where systematically referred to the same species they differ, as a rule, more or less markedly in minor details. The wapiti is a larger and handsomer form of our own red deer, with a nobler head and more superbly branching antlers. The caribou is a reindeer whose horns present some minor differences of tine and beam and technical arrangement. The moose is an elk, all but indistinguishable in any definite particular from the true elk of Northern Europe and Siberia. The silver birch and the chestnut are reckoned as mere varieties of the European type; but the nuts of the latter are smaller and sweeter than in our Spanish kind, and the leaves are narrower and acuter at the base. throughout. The beeches and larches differ even more widely; the hornbeams, elms, and nearest oaks have attained the rank of distinct species. Yet all along the northern Atlantic seaboard the original oneness of kind may still be easily traced in numberless cases; as we move southward along the shore or westward inland, unlikeness of type grows more and more accentuated at every step. We catch here species-making in the very act. Many of these marked differences must, indeed, have been evolved in the mere trifle of two hundred centuries or so which have now elapsed since the great polar ice-cap first cut off the American trees and shrubs and animals

So on

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