ect European Series Completed by Marsh's American Fossils-Meaning of Geological Contemporaneity-Uniformita

to elucidate. While he assisted in the routine work of determining the zo?logical position of the fossils sent in to the museum by the Survey, he carried investigations much farther than the duties of the post required when interesting zo?logical problems arose. His earliest notes were written in association with his colleague, and consisted of technical descriptions of some small fossils from the Downton Sandstones which were supposed to be fish-shields. The peculiarities of structure presented by these aroused his interest, and he began an elaborate series of investigations upon pal?ozoic fishes in general. Earlier zo?logists, such as the g

ma from the lower carboniferous of Scotland, and of several small forms from the coal-measures of Kilkenny, in Ireland, as well as describing skulls from Africa and a number of fragmentary bones from different localities. But in all this work it was the morphology of the creatures that interested him, and the light which their structure threw upon the structure of each other and of their nearest allies. He shewed that these monsters stood on the borderland between fishes, amphibia, and reptiles, and he added much to our knowledge of the true structure of these great groups. Next, he turned to the extinct reptiles of the Mesozoic age. It was generally believed that the Pterodactyls, or flying reptiles, were the nearest allies of birds, but Huxley insisted that the resemblances between the wings were simply such superficial resemblances as necessarily exist in organs adapted to the same purpose. About the same time, Cope in America, and Phillips and Huxley, in England, from study of the bones of the Dinosaurs, another great group of extinct reptiles, declared that these were the near

ll further backwards towards the common mammalian type of animal, with five fingers and five toes, and went the length of suggesting one or two fossils which might stand in the direct line of ancestry. But in 1876 he visited America, and had the opportunity of consulting the marvellous series of fossils which Professor Marsh had collected from American Tertiary beds. Professor Marsh allowed him the freest use of his materials and of his conclusions, and the credit of the final result is to be shared at least equally between Marsh and Huxley. The final result was a demonstrative

hich clearly answers to the upper end of the ulna. This is closely united with the chief mass of the bone which represents the radius, and runs out into a slender shaft which may be traced for some distance downwards on the back of the radius, and then in most

nee' thus corresponds to the middle finger in ourselves, what has become of the four other fingers or digits? We find in the places of the second and fourth digits only two slender splint-like bones, about two-thirds as long as the cannon bone, which gradually taper to their lower ends and bear no finger joints, or, as they are termed, phalanges. Sometimes small bony or gristly nodules ar

, to be reduced to its upper end; a short slender bone united with the tibia and ending in a point below occupying its place. Examination of the lower end of a young foal's shin-bone, however, shews a distinct portion of osseous matter, which is the l

oot, the pastern, coronary, and coffin bones, to the middle-toe bones; the hind hoof to the nail, as in the fore foot. And, as in the fore

ghly complicated and peculiar structure of

the tibia and fibula, distinct and separate. They have five distinct and complete digits on each foot, and no one of these digits is very much larger than the rest. Moreover, in the least modified mammals, the total number of the teeth is very generally forty-four, while in the horse the usual number is forty, and, in the absence of the canines,

digits on each foot; which had the bones of the forearm and of the leg complete and separate; and which possessed forty-four teeth, among which the crown of the incisors an

present us with a series of forms in which the number of the digits becomes reduced; the bones of the forearm and leg gradually take

how far they fulfill these require

like horses-which in fact are so similar to horses, that you may follow descriptions given in works upon the anatomy of the horse, upon the skeletons of these animals-but which differ in some important particulars. For example, the structure of their fore and hind limbs is somewhat different. The bones, which, in the horse are represented by two long splints, imperfect below, are as long as the middle metacarpal and metatarsal bones; and, attached to the extremity of each, is a digit with three joints of the same general characte

le. The fibula appears to be in the same condition as in the horse. The teeth of the Hipparion are essentially similar to those of the horse, but the pattern of the

discovered, which Cuvier, who first described some fragments of it, considered to be a Pal?otherium, but as further

ubtless rested on the ground in ordinary locomotion. The ulna is complete and quite distinct from the radius, although firmly united with the latter. The fibula seems also to have been complete; its lower end, though intimately united with that of the tibia, is clearly united with that of the latter bone. There are forty-four teeth; the incisors have no strong pit. The canines seem to have been well developed in both sexes. The first of the seven grinders,

horse from European fossils, Huxley goes on to relate the new light t

ery of America. Of late years there has been discovered in your Western territories that marvellous accumulation of deposits, admirably adapted for the preservation of organic remains, to which I referred the other evening, and which furnishes us with a consecutive series of records of the fauna of the older half of the Tertiary epoch, for which we have no parallel in Europe. The researches of Leidy and others have shewn that forms allied to the Hipparion and the Anchitherium are to be found among these remains. Rut it is only recently that the admirably conceived and most thoroughly and patiently worked-out investigations of Professor Marsh have given us a just idea of the vast fossil wealth and of the scientific importance of these

diagram, every figure of which is an actual representation of

Protohippus, which represents the European Hipparion, having one large digit and two small ones on each foot, and the general characters of the forearm and leg to which I have referred. But it is more valuable than the European Hipparion for the reason that it is devoid of some of the peculiarities of that form-peculiarities which tend to show that the European Hipparion is

he Eocene formations. An older Miocene form, called Mesohippus, has three toes in front, with a large splint-like rudiment representing the little f

ldest member of the equine series yet known. Here we find four complete toes on the front limb, three toes on

tifies us completely in the anticipation that, when the still lower Eocene deposits, and those which belong to the Cretaceous period have yielded up their remains of ancestral equine animals, we shall find, first, a form with four complete toes and a rudiment of the innermost or first digit

passed through the press, and he was able to add in a footnote some details of the structure of the four-toed Eohippus from the lower Eocene beds. Further discoveries have connected these with the five-toed ancestors of the Tapirs, and there is the strongest reason to suppose that we now know as nearly as possible the line of ances

logical Society gave him its chief distinction, awarding him the Wollaston Medal in recognition of his services to geological science. He acted as Secretary to the Geological Society from 1859 to 1862, and he was President from 1868 to 1870. In 1862, the President being incapacitated, Huxley delivered as Deputy-President the Presidential Addres

ies of sedimentary deposits, the bed which lies lowest is the oldest. In many other vertical l

ng vertically in the same order in different parts of the earth were deposited at

er any thoughtful geologist is asked whether he means to say that they were deposited at the same time, he says, 'No, only within the same great epoch.' And if, in pursuing the enquiry, h

ecies having been created at definite places at definite times had seen that time must have been required for sets of animals to wander from the places in which they had come into existence. The newer theory of evolution was equally opposed to the notion of the appearance of similar animals at the same time on far-distant parts of the earth. For such reasons he proposed to reject the use of the word Contemporaneous as appl

conclusions of science, and it was accepted generally that the earth was almost indefinitely old. At the same time, another and more strictly scientific dispute had been in progress. The older school of geologists, looking on the face of the world, and seeing it scarred by mighty fissures, displaying huge distortions of the beds in the crust, had argued that geological change had taken place by a series of mighty catastrophes. The tremendous results which they saw seemed to them only possible on the theory that unusual and gigantic displays of force had caused them. On the other hand, Hutton and Lyell attempted to find adequate explanation of the greatest changes in the slow forces which may be seen in operation at the present time. Slow movements of upheaval and depression, amounting at most to an inch or two in a century, may be shown to be actually in existence now, and such slow changes acting for very many centuries would account for t

the theorist might draw; and it has cherished the idea of development of the earth from a state in

ime, ready to discount any quantity of hypothetical paper. It has kept before our eyes the power of the infin

k in geology, an influence which may b

what I take to be the scope of geology itself. I conceive geology to be the history of the earth, in precisely the same sense as biology is the history of living b

find that the living being has certain powers resulting from its own activities, and the interaction of these with the activities of other things-the knowledge of which is Physiology. Beyond this, the living being has a position in space a

shall find that such earth-knowledge-if I may so tran

he earth; and the history of the succession of the formations is a history of the succ

ctivities and outward forces, as are the budding of the leaves in spring, and their falling in autumn the effects of the interaction between the organisation of a plant and the solar light and heat. And, as the study of the activities of the living being is called its physiology, so are these phenomena the subject matter of an analogous telluric physiology, to which we sometimes giv

earth, is the matter of its natural history. But, as in Biology, there remains the matter of reasoning from these facts

h are out of reach of direct observation; or, it may be physiological speculation so far as it relates to undetermined problems relative to the activities of the earth; or, it may be distributional speculation, if it deals with modifications of t

iking display of the wide knowledge of his reading by going back to the foundation of this branch of modern science, and giving a masterly account of the then little-known treatise of Immanuel Kant, who in 1775 had written An Attempt to Account for

Huxley, then, as all through the latter part of his life, at once constituted himself the champion of science, and, taking Thomson's arguments one by one, shewed by a series of masterly deductions from known facts that there was a great deal to be said for the other side, and that physicists were as little certain as geologists could be of the exact duration of time that had elapsed since the dawn of life. His plea for more time since the cooling of the globe than physicists were willing to allow remains one of the classics of geological literature. But he carried the question much farther. The inference which was widely drawn by the enemies of evolution from the arguments of Sir William Thomson was that if geologists had overestimated the age of the cooled earth there was not tim

the geological clock is wrong, all the naturalist will have to do is to modify his notion of the rapidity of change accordingly; and I venture to point out that, when we are told that the limitation of the period during which living beings h

son, between whom and Huxley there was no more than the desire to argue out an interesting scientific question upon which their conclusions differed, but betw

one might "sift and criticise them," they left a clear balance in favour of the doctrine of the evolution of living forms one from another. But, with his usual critical spirit, examining arguments that bore against a conclusion for which he hoped almost more stringently than arguments apparently favourable to what he expected to be true, Huxley made an important distinction, the value of which becomes more and more apparent as time goes on. In the first flush of enthusiasm for Darwinism, zo?logists and pal?ontologists allowed their zeal to outrun discretion in the formation of famil

t the mere discovery of such a form does not, in itself, prove that evolution took place by and through it, nor does it constitute more than a presumptive evidence in favour of evolution in general. The fact that Anoplotherid? are intermediate b

ssumed frequently that the gorilla, etc., were therefore to be regarded as ancestors of man, and they appear as such in more than one well-known treatise on evolutionary biology. We now know that it is exceedingly probable that the gorilla and its allies, although truly intermediate types, and truly shewing a possible path of evolution

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