under conditions of nearer proximity these differences may be less marked. It is well known that there is a great monotony of type, not only among animals and plants, but in the human races also, throughout the Arctic regions; and some animals characteristic of the high North reappear under such identical forms in the neighborhood of the snow-fields in lofty mountains that to trace the difference between the ptarmigans, rabbits and other gnawing animals of the Alps, for instance, and those of the Arctics, is among the most difficult problems of modern science. And so is it also with the animated world of past ages in similar deposits of sand, mud or lime in adjoining regions of the same geological age identical remains of animals and plants may be found; while at greater distances, but under similar circumstances, representative species may occur. In very remote regions, however, whether the circumstances be similar or dissimilar, the general aspect of the organic world differs greatly, remoteness in space being thus in some an indication of the degree of affinity between different faunæ. In de posits of different geological periods immediately following each other we sometimes find remains of animals and plants so closely allied to those of earlier or later periods that at first sight the specific differences are hardly discernible. The difficulty of solving these questions and of appreciating correctly the differences and similarities between such closely-allied organisms explains the antagonistic views of many naturalists respecting the range of existence of animals during longer or shorter geological periods, aud the superficial way in which discus sions concerning the transition of species are carried on is mainly owing to an ignorance of the conditions above alluded to. My own personal observation and experience in these matters have led me to the conviction that every geological period has had its own representatives, and that no single species has been repeated in successive ages. The laws regulating the geographical distribution of animals and their combination into distinct zoological provinces (called “faunæ ") with definite limits are very imperfectly understood as yet, but so closely are all things linked together from the beginning till to-day that I am convinced we shall never find the clue to their meaning till we carry on our investigations in the past and the present simultaneously. The same principle according to which animal and vegetable life is distributed over the surface of the earth now prevailed in the earliest geological periods. The geological deposits of all times have had their characteristic faunæ under various zones, their zoological provinces presenting special combinations of animal and vegetable life over certain regions, and their representative types reproducing in different countries, but under similar latitudes, the same groups with specific differences. Of course, the nearer we approach the beginning of organic life, the less marked do we find the differences to be, and for a very obvious reason. The inequalities of the earth's surface, her mountain-barriers protecting whole continents from the Arctic winds, her open plains exposing others to the full force of the polar blasts, her snug valleys and her lofty heights, her table-lands and rolling prairies, her river systems and her dry deserts, her cold oceancurrents pouring down from the high North on some of her shores, while warm ones from tropical seas carry their softer influence to others-in short, all the contrasts in the external configuration of the globe, with the physical conditions attendant upon themare naturally accompanied by a corresponding variety in animal and vegetable life. But in the Silurian age, when there were no elevations higher than the Canadian hills, when water covered the face of the earth, with the exception of a few isolated portions lifted above the almost universal ocean, how monotonous must have been the conditions of life! And what should we expect to find on those first shores? If we are walking on a sea-beach to-day, we do not look for animals that haunt the forests or roam over the open plains, or for those that live in sheltered valleys or in inland regions or on mountainheights. We look for shells, for mussels and barnacles, for crabs, for shrimps, for marine worms, for starfishes and sea-urchins, and we may find here and there a fish stranded on the sand or tangled in the seaweed. Let us remember, then, that in the Silurian period the world, so far as it was raised above the ocean, was a beach, and let us seek there for such creatures as God has made to live on seashores, and not belittle the creative work or say that he first scattered the seeds of life in meagre or stinted measure because we do not find air-breathing animals where there was no fitting atmosphere to feed their lungs, insects with no terrestrial plants to live upon, reptiles without marshes, birds without trees, cattle without grass-all things, in short, without the essential conditions for their existence. | What we do find-and these, as I shall endeavor to show my readers, in such profusion that it would seem as if God, in the joy of creation, had compensated himself for a less variety of forms in the greater richness of the early types-is an immense number of beings belonging to the four primary divisions of the animal kingdom, but only to those classes whose representatives are marine, whose home, then as now, was either in the sea or along its shores. In other words, the first organic creation expressed in its totality the structural conception since carried out in such wonderful variety of details, and purposely limited then because the world which was to be the home of the higher animals was not yet made ready to receive them. I am fully aware that the intimate relations between the organic and physical world are interpreted by many as indicating the absence rather than the presence of an intelligent Creator. They argue that the dependence of animals on material laws gives us the clue to their origin as well as to their maintenance. Were this influence as absolute and unvarying as the purely mechanical action of physical circumstances must necessarily be, this inference might have some pretence to logical probability, though it seems to me unnecessary, under any circumstances, to resort to climatic influences or the action of any physical laws to explain the thoughtful distribution of the organic and inorganic world, so evidently intended to secure for all beings what best suits their nature and their needs. But the truth is that, while these harmonious relations underlie the whole creation in such a manner as to indicate a great central plan of which all things are a part, there is at the same time a freedom, an arbitrary element, in the mode of carrying it out which seems to point to the exercise of an individual will, for side by side with facts apparently the direct result of physical laws are other facts the nature of which shows a complete independence of external influences. Take, for instance, the similarity above alluded to between the fauna of the Arctics and that of the Alps, certainly showing a direct relation between climatic conditions and animal and vegetable life. Yet even there, where the shades of specific difference between animals and plants of the same class are so slight as to baffle the keenest investigators, we have representative types both in the animal and vegetable kingdoms as distinct and peculiar as those of widely-removed and strongly-contrasted climatic conditions. Shall we at tribute the similarities and the differences alike to physical causes? Compare, for example, the reindeer of the Arctics with the ibex and the chamois, representing the same group in the Alps. Even on mountain-heights of similar altitudes, where not only climate, but other physical conditions, would suggest a recurrence of identical animals, we do not find the same, but representative, types. The ibex of the Alps differs, for instance, from that of the Pyrenees, that of the Pyrenees from those of the Caucasus and Himalayas, these again from each other and from that of the Altai. But perhaps the most conclusive proof that we must seek for the origin of organic life outside of physical causes consists in the permanence of the fundamen tal types, while the species representing these types have differed in every geological period. Now, what we call typical features of structure are in themselves no more stable or permanent than specific features. If physical causes, such as light, heat, moisture, food, habits of life, etc., acting upon individuals, have gradually in successive generations changed the character of the species to which they belong, why not that of the class and the branch also? If we judge this question from the material side at all, we must, in order to judge it fairly, look at it wholly from that point of view. If these specific changes are brought about in this way, it is because external causes have positive permanent effects upon the substances of which animals are built they have power to change their hair, to change their skin, to change certain external appendages or ornamentations, and any other of those ultimate features which naturalists call specific characters. Now, I would ask what there is in the substances. out of which class characters are built that would make them less susceptible to such external influences than these specific characters. In many instances the former are more delicate, more sensitive, far more fragile and transient in their material nature, than the latter, and yet never, in all the chances and changes of time, have we seer. any alteration in the mode of respiration, of reproduction, of circulation, or in any of the systems of organs which characterize the more comprehensive groups of the animal kingdom, although they are quite as much under the immediate influence of physical causes as those structural features which have been constantly changing. The woody fibre of the pine trees has had the same structure from the Carboniferous age to this day, while their mode of branching and the forms of their cones and leaves have been different in each period according to their respective species. The combination of rings, the structure of the wings and the articulations of the legs are the same in the cockroaches of the Carboniferous age as in those which infest our ships and our dwellings to-day, while the proportion of their parts is on quite another scale. The tissue of the corals in the Silurian age is identical in chemical combination and organic structure with that of the corals of our modern reefs, and yet the extensive researches upon this class for which we are indebted to Milne Edwards and Haime have not revealed a single species extending through successive geological ages, but show us, on the contrary, that every age has had its own kinds, differing among themselves in the same way as those of the Gulf of Mexico differ now from those of the Indian Ocean and the Pacific. The scales of the oldest known fishes in the Silurian beds have the same microscopic structure as those of their representative types to-day, and yet I have never seen a single fossil fish presenting the same specific characters in the successive geological epochs. The teeth of the oldest sharks show the same microscopic structure as those of the present time-and we do not lack opportunities for comparison, since the former are as common in the mountain-limestone of Ireland as are those of the living sharks on any beach where our fishermen boil them for the sake of their oil-and yet the sharks appear under different generic and specific forms in each geological age. per But without multiplying examples, which might be adduced ad infinitum to show manence of type combined with repeated changes of species, suffice it to say that while the general features in the framework of the organic world and the materials of which that framework is built, though quite as subject to the influence of physical external circumstances as any socalled specific features, have remained perfectly intact from the beginning of creation till now, so that not the smallest difference is to be discerned in these respects between the oldest representatives of the oldest types in the oldest Silurian rocks and their successors through all the geological ages up to the present day, the species have been different in each epoch. And those still deeper ideal relations, the plans or structural con ceptions upon which animals are based, are adhered to through all time with a tenacity in strange contrast to the perishableness of the material forms through which they are expressed. It is surely a fair question to ask the advocates of the transmutation theory whether they attribute to physical laws the discernment that would lead them to change the specific features, but to respect all those characters. by which the higher structural combinations of the animal kingdom are preserved without alteration-in other words, to maintain the organic plan while constantly diversifying the mode of expressing it. If so, it would perhaps be as well to call such laws by another name, since they show all the comprehensive wisdom of an intelligent Creator. Until they can tell us why certain features of animals and plants are permanent under conditions which, according to their view, have power to change certain other features no more perishable or transient in themselves, the supporters of the development theory will have failed to substantiate their peculiar scientific doctrine. The animal world is an intellectual creation complete in all its parts and coherent throughout; and when we find that, although ancient types have become obsolete and been replaced by modern ones, yet there are always a few old-fashioned individuals, left behind, as it were, to give the key to the history of their race-as the gar-pike, for instance, to explain the ancient fishes; the millepore, to explain the old acalephian corals; the nautilus, to be the modern exponent of the ammonites and orthoceratites of past times we cannot avoid the impression that this creative work has been intended also to be educational for man and to teach him his own relation to the organic world. The embryology of the modern types confirms this idea, for here we find an epitome of their geological history. The embryo of the present starfishes recalls the crinoids; the embryo of the crab recalls the trilobites; the embryo of the vertebrates, including even that of the higher Mammalia, recalls the ancient fishes. Does not this fact that the individual animal in its growth recalls the history of its type prove that the creative thought in its immediate present action embraces all that has gone before, as its first organic expression included all that was to come? The study of Nature in its highest meaning shows us the present doubly rich with all the past, and the past linked and interwoven with the present, not lying divorced and dead behind it. there were but one not only because I wished to limit my sketch and to attempt at least to give it the vividness of a special locality, but also because a single such shore will give us as good an idea of the characteristic fauna of the time as if we drew our material from a wider range. There are, however, a great number of parallel ridges belonging to the Silurian and Devonian periods running from east to west not only through the State of New York, but far beyond, through the States of Michigan and Wisconsin into Minnesota ; one may follow nine or ten such successive shores in unbroken lines from the neighborhood of Lake Champlain to the Far West. They have all the irregularities of modern seashores, running up to form little bays here and jutting out in promontories there, and upon each one are found animals of the same kind, but differing in species from those of the preceding. Although the early geological periods are more legible in North America because they are exposed over such extensive tracts of land, yet they have been studied in many other parts of the globe. In Norway, in Germany, in France, in Russia, in Siberia, in Kamtschatka, in parts of South America in short, wherever the civilization of the white race has extended-Silurian deposits have been observed, and everywhere they bear the same testimony to a profuse and varied creation. The earth was teeming then with life as now, and, in whatever corner of its surface the geologist finds the old strata, they hold a dead fauna as numerous as that which lives and moves above it. Nor do we find that there was any gradual increase or decrease of any organic forms. I have spoken of the Silurian beach as if at the beginning and close of the successive |