PALEONTOLOGICAL DISCOVERY. 377 



Cystidea, and Edrioasterida ; and the Crustaceans by the Eurypterida 

 and Trilobita. Among the vertebrates, no extinct order of fossil 

 fishes has yet been found ; but the amphibians have been enlarged by 

 the important order Labyrinthodonta. The greatest additions have 

 been among the reptiles, where the majority of the orders are extinct. 

 Here we have at the present date the Ichthyosauria, Sauranodontia, 

 Plesiosauria, and Mosasauria, among the marine forms ; the Pterosau- 

 ria, including the Pteranodontia, containing the flying forms ; and the 

 Dinosauria, including the Sauropoda — the giants among reptiles ; like- 

 wise the Dicynodontia, and probably the Theriodontia, among the ter- 

 restrial forms. Although but few fossil birds have been found below 

 the Tertiary, we have already among the Mesozoic forms three new 

 orders : the Saurura?, represented by Archceopteryx ; the Odontotor- 

 moB, with Ichtliyornis as the type ; and the Odontolca;, based upon 

 Ilesperornis ; all of these orders being included in the sub-class Odont- 

 ornithes, or toothed birds. Among mammals, the new groups re- 

 garded as orders are the Toxodontia and the Dinocerata, among the 

 Ungulates ; and the Tillodontia, including strange Eocene mammals 

 whose exact affinities are yet to be determined. 



Among the important results in vertebrate paleontology, are the 

 genealogies, made out with considerable probability, for various exist- 

 ing animals. Many of the larger mammals have been traced back 

 through allied forms in a closely connected series to early Tertiary 

 times. In several cases the series are so complete that there can be 

 little doubt that the line of descent has been established. The evolu- 

 tion of the horse, for example, is to-day demonstrated by the speci- 

 mens noAv known. The demonstration in one case stands for all. The 

 evidence in favor of the genealogy of the horse now rests on the same 

 foundation as the proof that any fossil bone once formed part of the 

 skeleton of a living animal. A special creation of a single bone is 

 as probable as the special creation of a single species. The method 

 of the paleontologist in the investigation of the one is the method 

 for the other. The only choice lies between natural derivation and 

 supern atural creation. 



For such reasons it is now regarded among the active workers in 

 science as a waste of time to discuss the truth of evolution. The 

 battle on this point has been fought and won. 



The geographical distribution of animals and plants, as well as 

 their migrations, has received much new light from paleontology. 

 The fossils found in some natural divisions of the earth are related 

 so closely to the forms now living there, that a genetic connection 

 between them can hardly be doubted. The extinct Marsupials of 

 Australia and the Edentates of South America are well-known ex- 

 amples. The Pliocene hippopotami of Asia and the south of Eu- 



