468 



SCIENCE. 



[Vol. Y., No. 122. 



did not add to this section of his introduction 

 a general survey of the animal life in each of 

 the periods which he afterwards treats in de- 

 tail. Such a summary would have been ex- 

 ceedingly useful. 



Before examining the book in detail, it will 

 be of advantage to direct the reader's atten- 

 tion to Dr. Hayden's summary of " the most 

 important contributions to paleontology and 

 evolution," contained in his letter of trans- 

 mittal of the volume before us. These are : 

 1°. The discovery of the Puerco fauna. This 

 includes the discovery and description of three 

 new families of a new order (the Taxeopoda) , 

 and a new sub-order (the Taligrada) ; also 

 the discover}' of the Plagiaulax type (of the 

 Jurassic), and other marsupials, and of a 

 genus of Laramie saurians. 2°. The discov- 

 ery of complete remains of the Wasatch types, 

 Phenacodus and Coryphodon. "The light 

 thrown on the phylogeny of the Ungulata by 

 this discovery exceeds that derived from all 

 other sources together." 3°. The new classi- 

 fication of the lower clawed mammals, founded 

 on the analyses of a great number of new gen- 

 era and species. 4°. The restoration of the 

 four-toed Wasatch horse, Hyracotherium. 5°. 

 The restoration of the Bridger genera, Hyra- 

 chyus and Triplopus. G°. The determination 

 of the systematic relations of the Dinocerata. 



Turning, now, to the body of the work, the 

 first chapter to demand notice is that on the 

 fishes. The shales of Green River, Bear 

 River, and Florissant, Col., have long been 

 famous for their abundance of fish-remains. 

 Our knowledge of these forms is almost en- 

 tirely due to Professor Cope, but hitherto he 

 has figured none of them. In the present vol- 

 ume there is a very welcome series of plates 

 that illustrates all the types. It is a pit}- that 

 Professor Cope has adopted the classification 

 he uses, which, being founded entirely on the 

 skeleton, and ignoring the structure of the 

 soft parts, is necessarily imperfect and mis- 

 leading. 



Perhaps Professor Cope's most signal ser- 

 vice to paleontology is his discovery of the 

 exceedingly curious and interesting Puerco 

 fauna, the earliest known from any tertiary 

 formation. This assemblage of mammals is 

 of extraordinary interest, both to the morphol- 

 ogist and the geologist, and goes a long way 

 towards bridging over the gap between the ter- 

 tiary and mesozoic ages. The characteristics 

 of this fauna were given above, but we must 

 again insist on the immense value of its dis- 

 covery. 



In the Wasatch, the second epoch of the 



eocene, we are presented with a no less inter- 

 esting series of mammals and reptiles. The 

 only full account extant of American tertiary 

 turtles and crocodiles is here given. Further, 

 our knowledge of the Wasatch mammals is 

 almost altogether owing to Professor Cope, 

 whose explorations of the Big Horn basin in 

 Wyoming yielded such extensive collections. 

 The chapters on the ungulates of this forma- 

 tion are of especial importance. The study of 

 these has confirmed the author's prediction, 

 made in 1873, that the earliest ungulates 

 would prove to be five-toed and plantigrade, 

 and has enabled him to construct a scheme of 

 all the ungulate series, which, however we 

 ma}' differ as to its details, must be admitted 

 to be a masterly presentation, and full of most 

 valuable suggestions. These chapters, and 

 especially the descriptions of the skeletons of 

 Periptychus from the Puerco, and the Wasatch 

 genera Phenacodus and Hyracotherium Owen 

 (Orohippus Marsh) , of which Professor Cope 

 gives the first complete account, are to be par- 

 ticularly commended to careful study. 



A very welcome section of the book is that 

 on the order Amblypoda, which includes the 

 Dinocerata and the Coryphodons. This order, 

 proposed in 1873 by Professor Cope, has re- 

 cently been adopted under the name of Am- 

 blydactyla by Professor Marsh. The latter 's 

 work on the Dinocerata is so much fuller and 

 more complete than Professor Cope's chapters 

 on them, that we need not stop to consider the 

 latter, except to mention the curious Bathy- 

 opsis. But nearly all that is known of the 

 Coryphodons is due to Professor Cope's labors, 

 and the value of his results in this field it is 

 difficult to exaggerate. 



Professor Cope has brought order out of the 

 chaos of the small mammals which abound in 

 the eocene, and which, with great diversity, 

 pass into each other by imperceptible grada- 

 tions. He groups together the early flesh- 

 eaters — which were not true carnivores, but 

 small-brained forms allied to the insectivores — 

 under the name Creodonta, giving in many 

 cases very complete accounts of their struc- 

 ture, and indicating the forms from which 

 descended the various families of the true 

 carnivores. The same service has been done 

 for the primitive lemurs, the most interesting 

 of which is the little Wasatch Anaptomorphus 

 homunculus, which has as large a brain as, and 

 in some respects a higher type of dentition 

 than, any existing lemur, and which seems to 

 be a progenitor of the monkeys. Did space 

 permit, the curious Taeniodonta would demand 

 notice. 



