Part 43

The seventh decade was productive of comparatively few great names in the history of our science, but two, J. A. Ryder and Samuel W. Williston, being notable contributors. The former produced but few papers and those between 1877 and 1892, yet they were of note and such was their influence that he is named with Hyatt, Packard, and Cope as one of the founders of the Neo-Lamarckian School of evolutionists in America. Ryder was a particular friend and a colleague of Cope, as they were both concerned with the back-boned animals, while the other two were invertebratists. Ryder wrote on mechanical genesis of tooth forms and on scales of fishes, also on the morphology and evolution of the tails of fishes, cetaceans, and sirenians, and of the other fins of aquatic types. He did, on the other hand, practically no systematic or descriptive work.

Williston, on the contrary, has had a long and varied career as an investigator and as an educator. Trained at Yale, he prepared for medicine, and much of his teaching has been of human anatomy, both at Yale and at the University of Kansas where he served for a number of years as dean of the Medical School. He is also a student of flies, and as such not only the foremost but indeed almost the only dipterologist in the United States. But it is with his work as a vertebrate paleontologist that we are chiefly concerned, and here again he stands among the foremost. His initial work and training in this department of science were with Marsh, for whom he spent many months in field work, collecting largely in the Niobrara Cretaceous of Kansas. He did, however, no research while with Marsh, owing to the latter’s disinclination to foster such work on the part of his associates. Williston began his publications in 1878 and has continued them until the present, working mainly with Cretaceous mosasaurs, plesiosaurs, and pterodactyls. Of late, since his transference to the University of Chicago, where as professor of paleontology and director of the Walker Museum he has served since 1902, his interest has lain mainly among the Paleozoic reptiles and amphibia. Williston’s more notable works are American Permian Vertebrates and Water Reptiles of the Past and Present, wherein he sets forth his views of the phylogenesis and taxonomy of the reptilian class. He is at present at work on the evolution of the reptiles, a volume which is eagerly awaited by his colleagues. It is in morphology that Williston’s greatest strength lies and some of his most effective work on the mosasaurs has appeared in the Journal.

1880–1900.

The next decade, that of 1880–1890, saw a number of notable additions to the workers in vertebrate paleontology: Henry F. Osborn, W. B. Scott, R. W. Shufeldt, J. L. Wortman, George Baur, F. A. Lucas, and F. W. True. Shufeldt is our highest authority on the osteology of birds, both recent and extinct, having recently described all of the extinct forms contained in the Marsh collection; True wrote of Cetacea; Lucas of marine and Pleistocene mammals and birds, and has also written popular books on prehistoric life. Lucas’s greatest service, however, lies in the museums, where he has manifested a genius second to none in the installation of mute evidences of living and past organisms. Wortman was for a time associated with Cope, later with Osborn in the American Museum, again at the Carnegie Museum at Pittsburgh, and finally at Yale in research on the Bridger Eocene portion of the Marsh collection. His work has been chiefly the perfection of field methods in vertebrate paleontology, and as a special investigator of Tertiary Mammalia, treating the latter largely from the morphologic and taxonomic standpoints. Wortman’s Yale results on the carnivores and primates of the Eocene, as yet unfinished, were published in the Journal in 1901–1904.

William B. Scott is a graduate of Princeton, and has spent thirty-four years in her service as Blair Professor of Geology and Paleontology. His first publication, in 1878, issued in conjunction with Osborn and Speir, described material collected by them in the Eocene formations of the West, and since that time Scott’s research has been entirely with the mammals, on which he is one of our highest authorities. His most notable works have been a History of Land Mammals of the Western Hemisphere, 1913, and the results of the Patagonian expeditions by Hatcher, which are published in a quarto series in conjunction with W. J. Sinclair, although they are the authors of separate volumes, Scott’s work being mainly on the carnivores and edentates of the Santa Cruz formation. It is as a systematist in research and as an educator that Scott has attained his highest usefulness.

The man who, next to the three pioneers, has attained the highest reputation in vertebrate paleontologic research, is Henry Fairfield Osborn. Graduate of Princeton in the same class that produced Scott, Osborn served for a time as professor of comparative anatomy in that institution, and in 1891 was called to New York to organize the department of zoology in Columbia University and that of vertebrate paleontology in the American Museum of Natural History. He had, early in his career, gone west in company with Professor Scott, and had collected material from the Eocene formation of Wyoming, upon which they based their first joint paper in 1878, Osborn’s first independent production, a memoir on two genera of Dinocerata, appearing in 1881. A number of papers followed, on the Mesozoic Mammalia, on Cope’s tritubercular theory, and on certain apparent evidences for the transmission of acquired characters. It was, however, with his acceptance of the New York responsibilities, especially at the American Museum, that Osborn’s most significant work began. Aided first by Wortman and Earle, later by W. D. Matthew and others, he has built up the greatest and most complete collection of fossil vertebrates extant; its value, however, was largely enhanced through the purchase of the private collection of Professor Cope, which of course included a large number of types. The American Museum collection thus contains not only a vast series of representative specimens from every class and order of vertebrates, secured by purchase or expedition from nearly all the great localities of the world, but an exhibition series of skulls and partial and entire skeletons and restorations which no other institution can hope to equal. Based upon this wonderful material is a large amount of research, filling many volumes, published for the greater part in the bulletin and memoirs of the Museum. This research is not only the product of the staff, including Walter Granger, Barnum Brown, W. D. Matthew, and W. K. Gregory, but also of a number of other American and some foreign paleontologists as well.

Professor Osborn’s own work has been voluminous, his bibliography from 1877 to 1916 containing no fewer than 441 titles, ranging over the fields of paleontology,—which of course includes the greater number—geology, correlation and paleogeography, evolutionary principles exemplified in the Mammalia, man, neurology and embryology, biographies, and the theory of education.

In paleontology, Osborn’s researches have been largely with the Reptilia and Mammalia, partly morphological, but also taxonomic and evolutional. Faunistic studies have also been made of the mammals. Of his published volumes the most important are, first, the Age of Mammals (1910), in which he treats not of evolutionary series of phylogenies, but of faunas and their origin, migrations, and extinctions, and of the correlation of Old and New World Tertiary deposits and their contents. Men of the Old Stone Age (1916) is an exhaustive treatise and is the first full and authoritative American presentation of what has been discovered up to the present time throughout the world in regard to human prehistory. In his latest volume, The Origin and Evolution of Life (1917), Osborn presents a new energy conception of evolution and heredity as against the prevailing matter and form conceptions. In this volume there is summed up the whole story of the origin and evolution of life on earth up to the appearance of man. This last book is novel in its conceptions, but it is too early as yet to judge of the acceptance of Osborn’s theses by his fellow workers in science.

Since the death of Professor Marsh, Osborn has served as vertebrate paleontologist to the United States Geological Survey, and has in charge the carrying through to completion of the many monographs proposed by his distinguished predecessor. One of these, that on the horned dinosaurs, has been completed by Hatcher and Lull (1907), another on the stegosaurian dinosaurs has been carried forward by C. W. Gilmore of the United States National Museum, while under Osborn’s own hand are the memoirs on the titanotheres (aided by W. K. Gregory), the horses, and the sauropod dinosaurs. Of these, the first, when it shall have been completed, promises to be the most monumental and exhaustive study of a group of fossil organisms ever undertaken.

As a leader in science, a teacher and administrator, Professor Osborn’s rank is high among the leading vertebratists. He is remarkably successful in his choice of assistants and in stimulating them in their productiveness so that their combined results form a very considerable share of the later literature in America.

The ninth decade ushered in the work of a valuable group of students, of whom John Bell Hatcher should be mentioned in particular, as his work is done. Graduate of Yale in 1884, he spent a number of years assisting his teacher, Professor Marsh, mainly in the field, collecting during that time, either for Yale or for the United States Geological Survey, an enormous amount of very fine material, especially from the West, although he also collected in the older Tertiary and Potomac beds near Washington. In the West he secured no fewer than 105 titanothere skulls, explored the Tertiary, Judith River, and Lance formations, collected and in fact virtually discovered the remains of the Cretaceous mammals and of the horned dinosaurs which he was later privileged to describe. He then (1893) went to Princeton, which he served for seven years, his principal work being explorations in Patagonia for the E. and M. Museum, one direct result of which was the publication of a large quarto on the narrative of the expedition and the geography and ethnography of the region. Going to the Carnegie Museum in Pittsburgh in 1900, Hatcher carried forward the work of exploration and collecting begun for that institution by Wortman, and as a partial result prepared many papers, the principal ones being memoirs on the dinosaurs Haplocanthosaurus and Diplodocus. In 1903, with T. W. Stanton of the United States Geological Survey, Hatcher explored the Judith River beds and together they settled the vexatious problem of their age, the published results appearing in 1905, after Hatcher’s death. His last piece of research, begun in 1902 and continued until his death in 1904, was an elaborate monograph on the Ceratopsia, one of the many projected by Marsh. Of this memoir Hatcher had completed some 150 printed quarto pages, giving a rare insight into the anatomy of these strange forms. The final chapters, however, which were based very largely upon Hatcher’s own opinions, had to be prepared by another hand.

Despite his early death, therefore, Hatcher rendered a very signal service to American paleontology—in exploration, stratigraphy, morphology, and systematic revision—and his activity in planning new fields of research, such, for instance, as the exploration of the Antarctic continent, gave promise of further high attainment, when his hand was arrested by death.

Summary.

It is not surprising that American vertebrate paleontology has arisen to so high a plane, when one considers the material at its disposal. Having a vast and virgin field for exploration, a sufficient number of collectors, some of whom have devoted much of their lives to the work, and a refinement of technique that permitted the preservation of the fragmental and ill conserved as well as the finer specimens, the results could hardly have been otherwise. Thus it has been possible to secure material almost unique throughout the world for extent, for completeness, and for variety. To this must be added a certain American daring in the matter of the restoration of missing portions, both of the individual bones and of the skeleton as a whole, such as European conservatism will not as a rule permit. This work has for the most part been done after the most painstaking comparison and research and is highly justified in the accuracy of the results, which render the fabric of the skeleton much more intelligible, both to the scientist and to the layman. Material once secured and prepared is then mounted, and here again American ingenuity has accomplished some remarkable results. Some of the specimens thus mounted are so small and delicate as to require holding devices comparable to those for the display of jewels; yet others—huge dinosaurs the bones of which are enormously heavy, but so brittle that they will not bear even the weight of a process unsupported—require a carefully designed and skilfully worked out series of supports of steel or iron which must be perfectly secure and at the same time as inconspicuous as possible. And of late the lifelike pose of the individual skeleton has been augmented by the preparation of groups of several animals which collectively exhibit sex, size, or other individual variations and the full mechanics of the skeleton under the varying poses assumed by the creature during life.

The work of further restoration has been rendered possible through comparative anatomical study, enabling us to essay restorations in entirety by means of models and drawings, clothing the bones with sinews and with flesh and the flesh with skin and hair, if such the creature bore; while the laws of faunal coloration have permitted the coloring of the restoration in a way which if not the actual hue of life is a very reasonable possibility.

Thus the American paleontologists have blazed a trail which has been followed to good effect by certain of their Old World colleagues.

With such means and methods and such material available, it is again not surprising that American paleontology has furnished more and more of the evidences of evolution, and disclosed to the eyes of scientists animal relationships which were undreamed of by the systematist whose research dealt only with the existing. It has also explained some vexatious problems of animal distribution and of extinction, and has connected up cause and effect in the great evolutionary movements which are recorded.

The results of systematic research have added hosts of new genera and species and of families, but of orders there are relatively few. Nevertheless a number, especially among reptiles and mammals, have come to light as the fruits of American discovery. But aside from the dry cataloguing of such groups, the American systematists have worked out some very remarkable phylogenies and have thus clarified our vision of animal relationships in a way which the recent zoologist could never have done. In this connection, the Permian vertebrates, which have been collected and studied with amazing success, principally by Williston and Case, should be mentioned, although the work is yet incomplete. Some of these forms are amphibian, others reptilian, yet others of such character as to link the two classes as transitional forms. Of the Mesozoic reptiles, a very remarkable assemblage has come to light, in a degree of perfection unknown elsewhere. These are dinosaurs, of which several phyla are now known; carnivores both great and small, some of the latter being actually toothless; Sauropoda, whose perfection and dimensions are incomparable except for those found in East Africa; and predentates, armored, unarmored, and horned, the last exclusively American. The unarmored trachodonts are now known in their entirety, for not only has our West produced articulated skeletons but mummified carcasses whose skin and other portions of their soft anatomy are represented, and which are thus far without a parallel elsewhere in the world. Other reptilian groups are well known, notably the Triassic ichthyosaurs, and the mosasaurs and plesiosaurs of the Kansas chalk. The last formation has also produced toothed birds, Hesperornis and Ichthyornis, which again are absolutely unique.

But it is in the mammalian class that the phylogenies become so highly complete and of such great importance as evolutionary evidences, for nowhere else than in our own West have such series been found as the Dinocerata and creodonts among archaic forms, the primitive primates from the Eocene, the carnivores such as the dogs and cats and mustellids, but especially the hoofed orders such as the horses. Of these hoofed orders, the classic American series of horses is complete, that of the camels probably no less so, while much is known of the deer and oreodonts, the last showing several parallel phyla, and of the proboscideans, which while having their pristine home in the Old World nevertheless soon sought the new where their remains are found from the Miocene until their final and apparently very recent extinction. These creatures show increase of bulk, perfection of feet and teeth, development of various weapons, horns and antlers, which may be studied in their relationship with the other organs to make the evolving whole, or their evolution may be traced as individual structures which have their rise, culmination, and sometimes their senile atrophy in a way comparable to that of the representatives of the order as a whole. Thus, for example, Osborn has traced the evolution of the molar teeth, and Cope of the feet, while Marsh has shown that brain development runs a similar course and that its degree of perfection within a group is a potent factor for survival.

As a student of evolution, the paleontologist sees things in a very different light from the zoologist. The latter is concerned largely with matters of detail—with the inheritance of color or of the minor and more superficial characteristics of animals—and the period of observation of such phenomena is of necessity brief because of the mortality of the observer. Whereas the paleontologist has a perspective which the other lacks, since for him time means little in the terms of his own life, and he can look into the past and see the great and fundamental changes which evolution has wrought, the rise of phyla, of classes, of orders, and he alone can see the orderliness of the process and sense the majesty of the laws which govern it.

Influence of the American Journal of Science.

The influence of the American Journal of Science as a medium for the dissemination of the results of vertebrate research has been in evidence throughout this discussion, but it were well, perhaps, to emphasize that service more fully. The Journal was, as we have seen, the chief outlet for Professor Marsh’s research, for there were published in it during his lifetime no fewer than 175 papers descriptive of the forms which he studied, as well as a great part of the material in the published monographs. As Marsh left very few manuscript notes, the importance of these frequent publications in thus setting forth much that he thought and learned concerning the material is very great indeed. The combined titles of all other authors in the Journal in this line of research for the century of its life fall far short of the number produced by Marsh alone, as they include 136 all told, but the range of subjects is highly representative of the entire field of vertebrate research. It should be borne in mind, moreover, that Leidy, Cope, and Osborn each had another medium of publication, which of course is true of other workers in the great museums such as the American, National, and Carnegie, all of which issue bulletins and quarto publications for the purpose of disseminating the work of their staff. Many of the earlier announcements of the discovery of vertebrate relics appeared in the Journal, as did practically all the literature of the science of fossil footprints (ichnology), except of course the larger quartos of Hitchcock and Deane. Of the footprint papers by Hitchcock, Deane, and others, there were no fewer than thirty-two, with a number of additional communications on attendant phenomena bones and plants.

Up to 1847, except for a few foreign announcements, the Journal published almost exclusively on eastern American paleontology, the only exception being a notice of bones from Oregon by Perkins in 1842. In 1847 came the announcement of a western “Palæothere” by Prout, which marked the beginning of the researches of Leidy and others in the Bad Lands of the great Nebraska plains. The Journal thenceforth published paper after paper on forms from all over North America, and on all aspects of our science: discovery, systematic description, faunal relationships, evolutionary evidences—thus showing that breadth and catholicity which has made it so great a power in the advancement of science.

VII THE RISE OF PETROLOGY AS A SCIENCE

By LOUIS V. PIRSSON

This chapter is intended to present a brief sketch of the progress of the science of petrology from its early beginnings down to the present time. The field to be covered is so large that this can be done only in broadest outline, and it has therefore been restricted chiefly to what has been accomplished in America. Although the period covered by the life of the Journal extends backward for a century it is, however, practically only within the last fifty years that the rocks of the earth’s crust have been made the subject of such systematic investigation by minute and delicately accurate methods of research as to give rise to a distinct branch of geologic science. It is not intended of course to affirm by this statement that the broader features of the rocks, especially those which may be observed in the field and which concern their relations as geologic masses, had not been made the object of inquiry before this time, since this is the very foundation of geology itself. Moreover, a certain amount of investigation of rocks, as to the minerals of which they were composed, the significance of their textures, and their chemical composition, had been carried out, concomitant with the growth from early times of geology and mineralogy. Thus, in 1815, Cordier by a process of washing separated the components of a basalt and by chemical tests determined the constituent minerals. At the time the Journal was founded, and for many years following, the genesis of rocks, especially of igneous rocks, was a subject of inquiry and of prolonged discussion. The aid of the rapidly growing science of chemistry was invoked by the geologists and analyses of rocks were made in the attempt to throw light on important questions. It is remarkable, also, how keen were the observations that the geologists of those days made upon the rocks, as to their component minerals and structures, aided only by the pocket lens. Many ideas were put forward, the essentials of which have persisted to the present day and have become interwoven into the science, whereas others gave rise to contentions which have not yet been settled to the satisfaction of all. At times in these earlier days the microscope was called into use to help in solving questions regarding the finer grained rocks, but this employment, as Zirkel has shown, was merely incidental, and no definite technique or purpose for the instrument was established.

On the other hand, the fact that up to the middle of the last century a large store of information relating to the occurrence of rocks, and to the mineral composition of those of coarser grain, and somewhat in respect to their structure, had been accumulated, caused attempts in one way or another to find means of coördinating these data and to produce classifications, such as those of Von Cotta and Cordier. The history of these attempts at classification, before the revelations made by the use of the microscope had become general, has been admirably reviewed by Whitman Cross and need not be further enlarged upon here.

That a considerable amount of work was done along chemical lines also is testified to by the publication of Roth’s Tabellen in 1861, in which all published analyses of rocks up to that date were collected. What was accomplished during this period was done chiefly on the continent of Europe, and little attention had been paid to the subject of rocks either in America or in Great Britain—even so late as 1870 Geikie remarks, as referred to by Cross, that there was no good English treatise on petrography, or the classification and description of rocks. In this country still less had been accomplished, interest being almost wholly confined to the vigorous and growing sciences of geology and mineralogy. This was natural, for mineralogy is the chief buttress on which the structure of petrology rests and must naturally develop first, especially in a relatively new and unexplored region, whose mineral resources first attract attention. The geologists in carrying out their studies also observed the rocks as they saw them in the field and made incidental reference to them, but investigations of the rocks themselves was very little attempted. An inspection of the first two series of the Journal shows relatively little of importance in petrology published in this country; a few analyses of rocks, occasional mention of mineral composition, of weathering properties, and notices of methods of classification proposed by French and German geologists nearly exhaust the list.