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.”