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.
But by far the most illuminating of the mid-century writers on Paleozoic vertebrates was Sir William Dawson, a very large proportion of whose numerous papers relate to the Coal Measures of Nova Scotia and their contained plant and animal remains. In 1853 appeared Dawson’s first announcement, written in collaboration with Sir Charles Lyell, of the finding of the bones of vertebrates within the base of an upright fossil tree trunk at South Joggins. These bones were identified by Owen and Wyman as pertaining to a reptilian or amphibian to which the name Dendrerpeton acadianum was given. Following this were several papers published in the Quarterly Journal of the Geological Society, London, describing more vertebrates and associated terrestrial molluscs. In 1863 Dawson summarized his discoveries in the Journal (36, 430–432) under the title of “Air-breathers of the Coal Period,” a paper which was expanded and published under the same title in the Canadian Naturalist and Geologist for the same year. Dawson also printed in the same volume the first account of reptilian(?) footprints from the coal. Thus from time to time there emanated from his prolific pen the account of further discoveries, both in bones and footprints, his final synopsis of the air-breathing animals of the Paleozoic of Canada appearing in 1895. The only other group of vertebrates which claimed his attention were certain whales, on which he occasionally wrote.
Fishes.—The fossil fishes from the Devonian of Ohio found their first exponent in J. S. Newberry, appointed chief geologist of the second geological survey of Ohio, which was established in 1869. These fishes from the Devonian shales belonged for the greater part to the curious group of armored placoderms, the remains of which consist very largely of armor plates with little or no traces of internal skeleton. There was also found in association a shark, Cladoselache, of such marvelous preservation that from some of the Newberry specimens now in the American Museum of Natural History, New York, Bashford Dean has demonstrated the histology of muscle and visceral organs, in addition to the very complete skeletal remains.
Newberry’s work on these forms, begun in 1868, has been carried to further completion by Bashford Dean and his pupil L. Hussakof, as well as by C. R. Eastman. Newberry’s other paleontological work was with the Carboniferous fishes of Ohio, the Carboniferous and Triassic fishes of the region from Sante Fé to the Grand and Green rivers, Colorado, and on the fishes and plants of the Newark system of the Connecticut valley and New Jersey. He also discussed certain mastodon and mammoth remains, and those of the peccary of Ohio, Dicotyles.
Joseph Leidy (1823–1891).
We now come to a consideration of the work of Joseph Leidy, one of the three great pioneers in American vertebrate paleontology, for if we disregard the work of Hitchcock and others on the fossil footprints, few of the results thus far obtained were based upon the fruits of organized research. Leidy began his publication in 1847 and continued to issue papers and books from time to time until the year 1892, having published no fewer than 219 paleontological titles, and 553 all told. His earlier paleontological researches were exclusively on the Mammalia, which were then coming in from the newly discovered fossil localities of the West. The discovery of these forms, one of the most notable events in the history of our science, will bear re-telling.
The first announcement was made in 1847, when Hiram A. Prout of St. Louis published in the Journal (3, 248–250) the description of the maxillary bone of “Palæotherium” (= Titanotherium proutii)from near White River, Nebraska. This at once drew the attention of geologists and paleontologists to the Bad Lands, or Mauvaises Terres, which were to prove so highly productive of fossil forms. About the same time S. D. Culbertson of Chambersburg, Pennsylvania, submitted to the Academy of Natural Sciences at Philadelphia some fossils sent to him from Nebraska by Alexander Culbertson. These were afterward described by Leidy in the Proceedings of the Academy, together with the paleotheroid jaw, in addition to which three other collections which had been made were also placed at his disposal for study.
This aroused the interest of Doctor Spencer F. Baird of the Smithsonian Institution, who sent T. A. Culbertson to the Bad Lands to make further collections. The latter was successful in securing a valuable series of mammalian and chelonian remains. These, together with other specimens from the same locality, were sent to Leidy, for, as Baird remarked, Leidy, although only thirty years of age, was the only anatomist in the United States qualified to determine their nature. The outcome of Leidy’s study of this material was “The Ancient Fauna of Nebraska,” published in 1853, and constituting the most brilliant work which up to that time American paleontology had produced. Leidy’s determinations, which are in the main correct, are the more remarkable when it is realized that he had little recent osteological material for comparative study. The forms thus described by him were new to science, of a more generalized character than those now living, and yet their distinguished describer recognized, either at that time or a little later, their true relationship to the modern types. The extent of Leidy’s anatomical knowledge was almost Cuvierian, and Cuvier-like he established the fact of the presence of the rhinoceroses, then unheard of in the American fauna, from a few small fragments of molar teeth, an opinion shortly to be fully sustained through the finding of complete molars and the entire skull of the same individual animal.
Leidy next turned his attention to the huge edentates, which he studied exhaustively, publishing his results in the form of a memoir in 1855, two years after the appearance of the “Ancient Fauna.”