Part 41

In connection with taxonomic research came increasingly tangible evidence in favor of the law of evolution; investigators turned to the working out of phyletic series showing the actual record of the successive evolutionary changes that the various races had undergone. Coupled with this evolutionary evidence came an increased attention to the sequential occurrence in successive geologic strata, and the stratigraphic distribution of vertebrates became known with greater and greater detail. Then followed the assemblage of faunas, which brought the study of the fossil forms within the realm of historical geology, rather than being the mere phylogeny of a single race, and the value of vertebrate fossils as horizon markers became more and more appreciated by the stratigrapher. They serve to supplement the knowledge gained from the invertebrates, and in this connection are especially valuable in that they often give data concerning continental formations about which invertebrate paleontology is largely silent.

Rise of Vertebrate Paleontology in Europe.

To those who had been nurtured in the belief in a relatively recent creation covering in its entirety a period of but six days, and occurring but four millenniums before the time of Christ, the appearance of the remains of creatures in the rocks, the like of which no man ever saw alive, must have given scope to the wildest imaginings concerning their origin and significance; for many believed that not only had no new forms been added to the world’s fauna since the creation, except possibly by hybridizing, but that none had become extinct save a very few through the agency of human interference. The supposition was, therefore, that such creatures as were thus discovered were still extant in some more remote fastnesses of the world. Thus, our second president, Thomas Jefferson, who wrote one of the first papers on American fossil vertebrates, published in 1798, discussed therein the remains of a huge ground-sloth which has since borne the name Megalonyx jeffersoni. Jefferson, however, described the great claws as pertaining to a huge leonine animal which he firmly believed was yet living among the mountains of Virginia.

Cuvier (1769–1832) has been spoken of as the founder of our science. His opportunity lay in the profusion of bones buried in the gypsum deposits of Montmartre within the environs of the city of Paris. Cuvier’s studies of these remains, done in the light of his very broad anatomical knowledge, enabled him to prepare the first reconstructions of fossil vertebrates ever attempted and to bring before the eyes of his contemporaries a world peopled with forms which were utterly extinct. That these creatures were no longer living, none was a better judge than Cuvier, for his prominence was such that material was sent him from all parts of the world, to which must be added that which he saw in his visits to the various museums of Europe. He felt it safe, therefore, to affirm the unlikelihood of any further discovery of unknown forms among the great mammals of the present fauna of our globe, and few indeed have been the additions since his day. To Cuvier is due not alone the masterly contribution to the sister sciences of comparative anatomy and vertebrate paleontology—the Ossements Fossiles (1812)—but he also announced the presence in continental strata of a series of faunas which showed a gradual organic improvement from the earliest such assemblage to the most modern, an idea of the most fundamental importance and one with which he is rarely credited. He believed in the sudden and complete extinction of faunas, and the facts then known were in accord with this idea, as no common genera nor transitional forms connected the creatures of the Paris gypsum with the mastodons, elephants, and hippopotami which the later strata disclosed. It is not remarkable, therefore, that Cuvier advanced his theory of catastrophism to account for these extinctions. He should not, however, according to Depéret, be credited with the idea of successive re-creations, such as that held by D’Orbigny and others, but of repopulation by immigration from some area which the catastrophe, be it flood or other destructive agency, failed to reach.

Cuvier was followed in Europe by a number of illustrious men, none of whom, however, with the exception of Sir Richard Owen, possessed his breadth of knowledge of comparative anatomy upon which to base their researches among the prehistoric. The more notable of them may be enumerated before going on to a discussion of the American contributions to the science.

They were, first, Louis Agassiz, a pupil of Cuvier and later a resident of America, whose researches on the fossil fishes of Europe are a monumental work, the result of ten years of investigation in all of the larger museums of that continent, and which appeared in 1833–43, while he was yet a young man. The fishes were practically the only fossil vertebrates to come within the scope of his investigations, for his later time was consumed in the study of glaciers and of recent marine zoology. Another student of these most primitive vertebrates who left an enduring monument was Johannes Mϋller. Huxley, Traquair, and Jaekel also did masterly work upon this group, while Smith Woodward of the British Museum is considered the highest living authority upon fossil fishes.

Of the Amphibia, the most famous foreign students were Brongniart, Jaeger, Burmeister, Von Meyer, and Owen, although Owen’s claim to eminence lies rather in the investigations of fossil reptiles which he began in 1839 and continued over a period of fifty years of remarkable achievement. Not only did he describe the dinosaurs of Great Britain in a series of splendidly illustrated monographs, but extended his researches to the curious reptilian forms from the Karroo formation of South Africa. It was to him, moreover, that the establishment of the true position of the famous Archœopteryx as the earliest known bird and not a reptile is due. Von Meyer also enriched the literature of fossil reptiles, discussing exhaustively those occurring in Germany, while Huxley’s classic work on the crocodiles as well as on dinosaurs, and the labors of Buckland, Fraas, Koken, Von Huene, Gaudry, Hulke, Seeley, and Lydekker have added immensely to our knowledge of the group.

Of the birds, which at best are rare as fossils, our knowledge, especially of the huge flightless moas, is due largely again to Owen, and his realization of the systematic position of Archœopteryx has already been mentioned.

The mammals were, perhaps, the most prolific source of paleontological research during the nineteenth century, for, as Zittel has said, Cuvier’s famous investigations on the fossil bones, mentioned above, not only contain the principles of comparative osteology, but also show in a manner which has never been surpassed how fossil vertebrates ought to be studied, and what are the broad inductions which may be drawn from a series of methodical observations. Such was Cuvier’s influence that until Darwin began to interest himself in mammalian paleontology the study of these forms was conducted entirely along the lines indicated by the French savant. This was seen in a large work, Osteology of Recent and Fossil Mammalia, by De Blainville, which, although not up to the standard set by the master, is nevertheless a notable contribution, as was also the Osteology prepared by Pander and D’Alton. A summary of the knowledge of the fossil Mammalia up to the year 1847 is contained in Giebel’s Fauna der Vorwelt, and Lydekker has done for the mammals in the British Museum what Smith Woodward did for the fishes, producing vastly more than the mere catalogue which the title implies.

The first work wherein the fossil mammals were treated genealogically was Gaudry’s Enchaînements du Monde Animal, written in 1878. Other work on the fossil Mammalia was done by Kaup, who described those from the Mainz basin and from Epplesheim near Worms whence came one of the most famous of prehistoric horses, the Hipparion; this horse, together with the remarkable proboscidean Dinotherium, was described by Von Meyer. One of the most remarkable discoveries, ranking in importance, perhaps, next to Montmartre, was that of the Pliocene fauna of Pikermi near Athens, Greece, first made known through the publications of A. Wagner of Munich and later, and much more extensively, through that of Gaudry (1862–1867). H. von Meyer was Germany’s best authority on fossil Mammalia. After his death the work was carried on by Quenstedt, Oscar Fraas, Schlosser, Koken, and Pohlig, among others.

In France, rich deposits of fossil mammals were discovered in the Department of Puy-de-Dôme, the Rhone basin, Sansan, Quercy, and near Rheims. These were described by a number of writers, notably Croizet and Jobert, Pomel, Lartet, Filhol, and Lemoine.

Rütimeyer of Bâle was one of the most famous European writers on mammalian paleontology, and his researches were both comprehensive and clothed in such form as to give them a high place in paleontological literature. He studied comparatively the teeth of ungulates, discussed the genealogy of mammals, and the relationships of those of the Old and New Worlds. He was an exponent of the law of evolution as set forth by Darwin, and his “genealogical trees of the Mammalia show a complete knowledge of all the data concerning the different members in the succession, and are amongst the finest results hitherto obtained by means of strict scientific methods of investigation” (Zittel, History of Geology and Palæontology, 1901). The mammals of the Swiss Eocene have been studied in much detail by Stehlin.

For Great Britain, the most notable contributors were Buckland in his Reliquiæ Diluvianæ; Falconer, co-author with Cautley on the Tertiary mammals of India; Charles Murchison, who wrote on rhinoceroses and proboscideans; and more recently Bush, Flower, Lydekker, Boyd Dawkins, L. Adams, and C. W. Andrews. But by far the most commanding figure of all was Sir Richard Owen, who for half a century stood without a peer as the greatest of authorities on fossil mammals. It was the Natural History of the British Fossil Mammals and Birds, published in 1846, that established Sir Richard’s reputation.

Russia has produced much mammalian material, especially from the Tertiary of Odessa and Bessarabia, and from the Quaternary of northern Russia and Siberia. These have been described mainly by J. F. Brandt, A. von Nordmann, but especially by Mme. M. Pavlow of Moscow.

Forsyth-Major discovered in 1887 a fauna contemporaneous with that of Pikermi in the Island of Samos in the Mediterranean.

One of the most remarkable recent discoveries of fossil localities was that announced in 1901 by Mr. Hugh J. L. Beadnell of the Geological Survey of Egypt and Doctor C. W. Andrews of the British Museum of London, of numerous land and sea mammals of Upper Eocene and Lower Oligocene age in northern Egypt. The exposures lay about 80 miles southwest of Cairo in the Fayûm district and are the sediments of an ancient Tertiary lake, a relic of which, Birket-el-Qurun, yet remains. These beds contained ancient Hyracoidea, Sirenia, and Zeuglodontia, but above all, ancestral Proboscidea which, together with those known elsewhere, enabled Andrews to demonstrate the origin and evolutionary features of this most remarkable group of beasts. This discovery in the Fayûm lends color to the belief that Africa may have been the ancestral home of at least five of the mammalian orders, those mentioned above, together with the Embrithopoda, a group unknown elsewhere. This theory had been advanced independently by Tullberg, Stehlin, and Osborn, before the discovery in Egypt.

Another European worker of pre-eminence who wrote more broadly than the faunal studies mentioned above was W. Kowalewsky. He discussed especially the evolutionary changes of feet and teeth in ungulates, a line of research afterward developed in greater detail by the Americans, Cope and Osborn.

South America has yielded series of rich faunas which have been exploited by the great Argentinian, Florentino Ameghino, and by the Europeans, Owen, Gervais, Huxley, Von Meyer, and more recently by Burmeister and Lydekker. Later exploration and research by Hatcher and Scott of North America will be discussed further on in this paper.

Vertebrate Paleontology in America.

Early Writers.—Having thus summarized paleontological progress in the Old World, we can turn to a consideration of the work done in the New, especially in the United States, because while the Old World investigation has been invaluable, a science of vertebrate paleontology, very complete both as to its zoological and geological scope and in the extent and value of published results, could be built exclusively upon the discoveries and researches made by Americans. The science of vertebrate paleontology may be said to have had its beginnings in North America with the activities of Thomas Jefferson, who, like Franklin, felt so strong an interest in scientific pursuits that even the graver duties of the highest office in the gift of the American people could not deter him from them. When in 1797 Jefferson came to be inaugurated as vice-president of the United States, he brought with him to Philadelphia not only his manuscript but the actual fossil bones upon which it was based. Again in 1801 he was greatly interested in the Shawangunk mastodon, despite heavy cares of state, and in 1808 made part of the executive mansion in Washington serve as a paleontological laboratory, displaying therein for study the bones of proboscideans and their contemporaries which the Big Bone Lick of Kentucky had produced. Jefferson’s work would not, perhaps, have been epoch-making were it not for its unique chronological position in the annals of the science.

Jefferson was followed by another man—this time one whose diverging lines of interest led him not into the realm of political service, but of art, for Rembrandt Peale possessed an enviable reputation among the early painters of America. Peale published in 1802 an account of the skeleton of the “mammoth,” really the mastodon, M. americanus, speaking of it as a nondescript carnivorous animal of immense size found in America. It was because of the form of the molar teeth that Peale said of it: “If this animal was indeed carnivorous, which I believe cannot be doubted, though we may as philosophers regret it, as men we cannot but thank Heaven that its whole generation is probably extinct.”

With the work of these men as a beginning, it is not strange that the more conspicuous Pleistocene fossils of the East should have attracted the attention of many subsequent writers in the first part of the nineteenth century, nor that the early papers to appear in the Journal should pertain to proboscideans or to the huge edentate ground-sloths and the aberrant zeuglodons whose bones frequently came to light. Therefore a number of men such as Koch, both Sillimans, J. C. Warren, and others made these forms their chief concern.

Fossil Footprints.—Among the early writers who concerned themselves with these greater fossils was Edward Hitchcock, sometime president of Amherst College, and a geologist of high repute among his contemporaries. Hitchcock is, however, better and more widely known as the pioneer worker on a series of phenomena displayed as in no other place in the region in which he made his home. These are fossil footprints impressed upon the Triassic rocks of the Connecticut valley. It was in the Journal for the year 1836 (=29=, 307–340) that Hitchcock first called attention to the footmarks, although they had been known and discussed popularly for a number of years previous. James Deane, of Greenfield, was perhaps the first to appreciate the scientific interest of these phenomena, but deeming his own qualifications insufficient properly to describe them, he brought them to the attention of Hitchcock, and the interest of the latter never waned until his death in 1864. Hitchcock wrote paper after paper, publishing many of them in the Journal, again in his Final Report on the Geology of Massachusetts (1841), and later in quarto works, one in the Memoirs of the American Academy of Arts and Sciences and the two others under the authority of the Commonwealth, the Ichnology in 1858, and the Supplement in 1865, the last being a posthumous work edited by his son, Charles H. Hitchcock.

Hitchcock’s conception of the track-makers was more or less imperfect because of the fact that for a long time but a few fragmentary osseous remains were known, either directly or indirectly associated with the tracks, while on the other hand the bird-like character of many of the latter and the discovery of huge flightless birds elsewhere on the globe suggested a very close analogy if not a direct relationship. Hence “bird tracks” they were straightway called, a designation which it has been difficult to remove, even though in 1843 Owen called attention to the need of caution in assuming the existence of so highly organized birds at so early a period, especially when large reptiles were known which might readily form very similar tracks. The footprints are now believed to be very largely of dinosaurian origin, and dinosaurs whose feet corresponded in every detail with the footprints have actually come to light within the same geologic and geographic limitations. This of course refers to the bipedal, functionally three-toed tracks. Of the makers of certain of the obscurer of the quadrupedal trails we are as much in the dark to-day as were the first discoverers of a century ago, so far as demonstrable proof is concerned. We assume, however, that they were the tracks of amphibia and reptiles, beyond which we may not go with certainty.

Agassiz, writing in 1865 (Geological Sketches), says:

“To sum up my opinion respecting these footmarks, I believe that they were made by animals of a prophetic type, belonging to the class of reptiles, and exhibiting many synthetic characters. The more closely we study past creations, the more impressive and significant do the synthetic types, presenting features of the higher classes under the guise of the lower ones, become. They hold the promise of the future. As the opening overture of an opera contains all the musical elements to be therein developed, so this living prelude of the creative work comprises all the organic elements to be successively developed in the course of time.”

Of those whose work was contemporaneous with that of Hitchcock, but one, W. C. Redfield, wrote on Triassic phenomena, and he concerned himself mainly with the fossil fishes of that time, his first paper on this subject appearing in 1837 in the Journal (=34=, 201), and the last twenty years later.

Paleozoic Vertebrates.—Later the vertebrates of the Paleozoic began to attract attention, footprints from Pennsylvania being described by Isaac Lea, beginning in 1849, a notice of his first paper appearing in the Journal for that year (=9=, 124). Several papers followed on the reptile Clepsysaurus. Alfred King also wrote on the Carboniferous ichnites, his work slightly antedating that of Lea, but being less authoritative.