4° 



HARD WI CKE 'S SCIE NCE - G O SSI P. 



THE HORNED HOOFED MAMMALS OF 

 THE EOCENE PERIOD IN AMERICA. 



(DINOCERATA.) 



IN Science-Gossip for February 1881, I gave, 

 under the heading of " Bird Studies in Chalk," a 

 resume of the contents of vol. i. of the " Trans, of the 

 Peabody Museum of Yale College," in which Pro- 

 fessor O. C. Marsh of Newhaven, Conn., detailed 

 the history of the strange toothed birds (Odontor- 

 nithes), discovered by him in 1 872-5 in the cre- 

 taceous deposits of the eastern slopes of the Rocky 

 Mountains. 



Since the publication of that volume, the inde- 

 pendent geological surveys and explorations of various 

 states have been consolidated as the " Geological 

 Survey of the United States Government," with 

 Major J. W. Powell, as director, and the entire 

 department of vertebrate palaeontology, placed under 

 the control of Professor O. C. Marsh, " palaeontologist 

 in charge." This accounts for the change of title 

 nnd mode of publication of his second volume of 

 contributions to knowledge of the extinct American 

 vertebrate fauna, which has recently appeared as vol. x. 

 of the " Memoirs of the United States Geological 

 Survey." It forms a complete and fully illustrated 

 history " of the dinocerata, an extinct order of 

 gigantic mammals,"* of which the chief structural 

 characters were made known as discovered from time 

 to time in the " American Journal of Arts and 

 Sciences," from the year 1871 and upwards. The 

 present monograph is a well-printed and richly 

 illustrated quarto with fifty-six finely executed litho- 

 graphic plates, and over 190 original woodcuts 

 separately illustrating every bone of the skeletons of 

 both sexes, and various ages of these animals, and 

 mainly drawn from the very large number of speci- 

 mens obtained by Professor Marsh during different 

 expeditions of the Yale College exploring parties in 

 1870, 1871, 1872, and following years. His collection 

 at Newhaven now comprises more or less perfect parts 

 of the skeletons, including seventy-five skulls, more 

 than twenty nearly perfect, of at least 200 indi- 

 viduals of a horned race of large hoofed mammals that 

 abounded by the swampy shores of a tropical and 

 extensive lake basin in the middle Eocene period. 



Professor Marsh describes this ancient lake basin 

 ns bounded then as now, west, by the Waksatch, 

 south, by the Uintah Mountains, and on the north by 

 the Wind river range, which furnished the sediments 

 by which it was gradually filled up. It now lies at 

 an elevation of from 6000 to Sooo feet above sea 

 level in western Wyoming, and is drained by the 

 Green River, main affluent of the mighty Colorado, 



* Dinocerata, an extinct order of gigantic mammals, by 

 Othniel Charles Marsh. Vol. x. of the United States Geolo- 

 gical Survey, Washington, 1884. The publication of this 

 article has been accidentally delayed, (rid. Sc.-Gos.) 



which has carried away half of its former thickness of 

 strata. For the Eocene deposits in this region are 

 stated on good evidence to have once reached 

 vertical mile in thickness. This estimate requires 

 such an enormous lapse of time, both for deposition 

 and partial erosion, as would amply suffice for the 

 development and specialisation of the rich and varied 

 fauna the area, 100 miles in extent, has already yielded 

 to the hardy scientist explorers. Crocodiles, the 

 ancestors of the modern bony pike, and fresh water 

 dog-fishes, abounded in these waters, by which the 

 ancestral forms of the present horse and tapir were 

 refreshed, together with a vast number of flesh- 

 eating, insect-feeding, and marsupial animals. Here 

 dwelt the big-framed Tillodont, unlike all living 

 mammals, with the ancestors of the little lemuroid 

 monkey ; and the huge horned dinocerata, half 

 elephant, part rhinoceros, and part hippo, wallowed 

 in the neighbouring swamps, or contended for mastery 

 under the palms amid a tropical vegetation, sheltering 

 insects, serpents and lizards. 



The investigations of Professor Marsh prove, that 

 the bulky horned animals he has called dinocerata 

 (deinos, terrible, keras, horn), form a well-marked 

 order, allied both to the odd-toed and even-toed 

 divisions of the great group of hoofed mammals 

 (ungulata), uniting in their structure features of the 

 elephant rhinoceros, and suggestions of the hippo- 

 potamus. " They were," he says, " the monarchs of 

 the region in which they lived." The larger forms 

 measured twelve feet long, five feet across the loins, 

 stood over six feet high, and weighed at least 6000 lbs. 

 Their necks were much longer, and far more flexible 

 than those of the existing elephants, and they had 

 no trunk, but their heavy heads were armed with 

 three pairs of horny protuberances, which suggested 

 the family name of the group. One pair of horn 

 cores was near the nostrils (nasal), another (maxillary) 

 on the cheek bones, and the third (parietal) near the 

 top of the head. These defensive weapons were 

 most developed in males, which were also furnished 

 with large upper canine teeth so enormously deve- 

 loped, as to form two decurved tusks often some inches 

 long, and fitting into a protective depression in the 

 lower jaw, a special character of this group of 

 animals. The molar teeth foreshadow the rhinoce- 

 rine type. The dinocerata limb-bones were large and 

 solid, and the foot flat-footed with five toes in each 

 foot, the hinder pair being the smaller. The mode 

 of union of the composing bones intermediate between 

 that of the odd-toed and even-toed hoofed mammals, 

 bridges over — as Huxley long ago predicted the 

 earlier fossil forms would — the gulf between those 

 two divisions of the ungulata. 



(To be continued.) 



M. TuLASNE, the distinguished French botanist 

 and fun ologist, is dead. 



