512 Reviews — Prof. Edward D. Cope — 



REVIEWS. 



I. — Department of the Interior. Report of the United States 

 Geological Survey of the Territories. F. V. Hayden, United 

 States Geologist-in-Charge. Volume III. The Vertebrata 

 of the Tertiary Formations of the West. Book I. By 

 Edward D. Cope, Member of the National Academy of Sciences. 

 (Washington, Government Printing Office, 1883.) 



[Continued from p. 477.) 



THE rocks of Middle Tertiary Age, which are found in the far 

 west of the United States, are calcareous clays and marls, 

 alternating with light-coloured sandstone. In Oregon they are often 

 old trachytic muds, three to four thousand feet thick, and about 

 2300 feet thick in Nevada. But on the White Eiver in Nebraska the 

 thickness of these rocks is reduced to 150 feet, and there the strata 

 are divided by Hayden into eight zones. The Oregon beds are 

 typically seen on the John Day River, so that the White River and 

 the John Day beds are regarded as equivalent, and belong to the 

 Miocene series. These rocks, hitherto have yielded no Fishes or 

 Amphibia, and no traces of Birds ; so that the discussion of their 

 fauna is limited to Reptiles and Mammals. 



The striking feature of the reptilian life, as compared with that of 

 the older Eocene series, is the absence of Crocodiles, the decrease 

 in number of species of Tortoises, with an increase of Lizards 

 and Serpents. But none of the Reptiles are remarkable for size, 

 and are similar in proportions to those now living in the same 

 region. The author commences with the genus Testudo, which is 

 represented by five species in the White River beds of Colorado. 

 They are distinguished by the form of marginal bones, the shape 

 of gular scutes and other characters. T. quadratus is the largest, 

 T. laticuneus the best preserved. Some of the species are only 

 described from a few bones, because the difficulties of transport com- 

 pelled the author to select such as were most characteristic, often 

 leaving the bulk of the specimens behind. The only other Chelonian 

 is Leidy's Stylemys nebrascensis. 



The Lizards are for the most part founded upon fragmentary 

 remains. JPeltosanrus, however, is well preserved. In this genus 

 the temporal fossa is not roofed over by bone, but is rather small ; 

 the orbits are large. Two median dermal scutes, which represent 

 the interparietal and postinterparietal plates, have left impressions 

 on the parietal bone. The genus is distinguished from Gerrhonotus, 

 by having had the body covered with bony scutes, which were 

 rectangular, and arranged in transverse bands, joined at the sides by 

 minute sutures, and overlapping in an imbricated method. The 

 hexagonal scutes on the skull are one of its most distinctive charac- 

 ters ; one species is known. Exostinus, very imperfectly known, 

 appears to be related to Peltosaurus, but that genus has the frontal 

 region much wider, and wants the tubercles along the supra-orbital 

 border. Aciprion formosum is a Lizard known from a dentary bone, 



