Page images





I have chosen the subject which has just been, announced by the Chairman, because I have been so long identified with the geological and paleontological work of our country that I think you will naturally expect my retiring address to have reference to some subject connected with the biological history of the earlier ages of the earth. It has become customary upon occasions like the present for the speaker to select some subject relating to his own special lines of research ; and it is often the case that such addresses are real contributions to science and records of its advancement, as indeed it is well that they should be ; but after much hesitation I have decided that my remarks upon this occasion shall be of a somewhat opposite character. That is, I shall endeavor to show that certain prevalent ideas are erroneous, and, incidentally, how they have retarded rather than aided philosophical inquiry.

It is much pleasanter for one to record and announce the triumphs of long and patient research, and to show the evidence of a steady increase of knowledge in the branch of study to which he is devoted, than to point out the existence of errors in unexpected quarters. But it is well that we should pause occasionally in our labors and question the truth of every proposition upon

* Annual presidential address delivered at the Fifth Anniversary Meeting of the Society, January 24, 1885, in the lecture-room of the U. S. National Museum.

which we have been wont to act, and to inquire whether they will bear the light of rapidly increasing knowledge. I propose to-night not only to point out the insufficiency of the evidence which is relied upon to support some of the assumptions of paleontology, but to challenge the truth of some of the propositions which its leading men have been in the habit of treating as fixed laws of unquestionable and universal application, and to show that they are not in harmony with the facts of philosophical biology. I comprehend the danger that those who are not familiar with the leading principles of paleontology, hearing only a statement of the misconceptions which its votaries have fallen into, will be inclined to underestimate its fundamental truths, which are really unassailable. I wish to say, therefore, that I have no intention of treating my subject wantonly; and I shall be sorry to weaken the faith of any one in the general truths of a science which has done more than any other to broaden the minds of men as to the problems of animal and vegetable life ; and which has a future before it, the brilliance of which is in no danger of being obscured.

The remarks which I am about to make refer mainly to certain errors, not yet entirely eliminated, which early obtained a foothold in paleontology, as a natural consequence of the biological opinions then prevailing, and which were inseparable from its stage of transition and growth. Modern paleontology, like the other sciences, has been a matter of growth; and errors once introduced have been found difficult to eradicate, even after an increase of knowledge has shown them to be such ; and it is an unpleasant fact that our science, as it is now taught and practised, even by some of the best authors, is marred by some of its early defects.

The first and principal question which I propose to discuss relates to the chronological order of succession of animal and vegetable types, and their geographical distribution during their existence.


As aids to the correlation of the geological formations, fossils began early to be used. At first they were treated merely as tokens of the formations in which they occurred, without any reference to their character as representatives of formerly existing life; but it was soon perceived that by their use a systematic classification of the stratified rocks could be made. We now know that without their use we could not have obtained any adequate conception of geological history; and the present recognized scheme of the formations, or the geological scale, as it is sometimes called, could have never been devised. It is true that the order of succession of the few formations which may be favorably exposed in limited districts might have been made out by means of the lithological character of the strata alone ; but the correlation of such limited groups of strata with those of other and distant districts would have been by such means impossible.

After the order of succession of the different groups of strata had been made out for certain regions and correlated with those of other regions, it began to appear that certain types of animal and vegetable remains characterized certain portions of the geological scale which was devised as a result of that correlation. That scale, which is the foundation of the one now in general use, was necessarily at first more or less defective and artificial. It has from time to time been much improved, and, although it is still imperfect, it is a marvellous monument of the results of inductive reasoning. Geology and biology have each come to the other's aid until not only has the foundation been substantially laid, but the structure itself is approaching completion in a perfect form.

In Europe, where geological science was first studied, and where it has ever since been prosecuted with remarkable energy, it was found that the chronological range of the types of fossils which characterize the respective formations is well defined. And when researches were extended into the adjacent parts of

Asia and Africa, the European standards were still found sufficiently exact for at least general conclusions. Even in Eastern North America the order of the formations and the types of the fossils which characterize them are closely like those of Western Europe, and in many cases the species are regarded as identical.

It was natural, then, that the conditions which were found to have formerly prevailed in those regions where geology was first studied should be held to have been the normal conditions for the whole earth. Such were the opinions formed by the earlier European geologists; and their successors still hold the European standard to be applicable to every region, and to every condition of climate which the earth has known. The leading idea which is embodied in this chronological scheme would, I think, be fairly illustrated by a diagram which may be constructed by taking such a section of the geological formations as is usually given in the text-books of geology, that of Dana's Manual for example, and projecting a series of circular lines from the boundary lines of each of its divisions and subdivisions. Let this series of circles represent approximately the time-equivalent of the geological column of formations and the assumed universal definition of each of its subdivisions.

It will of course be understood that such a diagram could not be intended to illustrate the time ratios of the different epochs, periods, and ages into which historic geology has been divided. It has been suggested only to illustrate the rigid character of the paleontological time-standard which European geologists have erected for themselves, and which they seek, with the consent of most of the geologists of other countries, to apply to the whole earth, even in minute detail.

It was formerly held that not only have all species of animals and plants been specially created, but that a majority of them became extinct during or at the close of each epoch ; and that each period was closed with a universal catastrophe, by which

« EelmineJätka »