PALEONTOLOGY 121 



that* if fishes were evolved, their history as verte- 

 brates began far back in the Archaean. The entire 

 record of fossils in the Archaean, if they ever existed 

 there, has been obliterated, so that there can be no 

 hope that fossils will be discovered which will reveal 

 the earliest forms of vertebrates. 



Evolution must assume either that the first verte- 

 brates were evolved from invertebrates of the Pri- 

 mordial period, of which there is no evidence given 

 by fossils, or that there is an immensely long but lost 

 record in the Archaean. 



If this were the only assumption of the kind neces- 

 sary in the history of the vertebrates it might be just- 

 ifiable, but a similar assumption becomes necessary 

 for every class and order of vertebrates, and for every 

 class and order of the entire animal kingdom. 



I quote again from Huxley's address with regard to 

 the geological record of vertebrates. It will be 

 noticed that his remarks apply to parts of the geolog- 

 ical record where fossils are abundant, and in which 

 the beginnings of new forms ought to have been pre- 

 served. 



He says: "The same moral is inculcated by the 

 study of every other order of Tertiary monodelphons 

 Mammalia. Each of these orders is represented in 

 the Miocene Epoch; the Eocene formation, as I have 

 already said, contains Cheiroptera, Insevtivora, Rod- 

 entia, Ungulata, Oarnivora and Cetacea. But the 

 Cheiroptera are extreme modifications of the Insectiv- 

 ora, just as the Cetacea are extreme modifications of 

 the Carnivorous type; and therefore it is to my mind 

 incredible that monodelphons Insectivora and Oar- 

 nivora should not have been abundantly developed 

 along with Ungulata in the Mesozoic epoch. But if 

 this be the case, how much further back must we go 

 to find the common stock of the monodelphous Mam- 



