232 EXTINCT MONSTERS 



the world's extinct races which has taken place during the last 

 quarter of a century ought to make us careful with regard to 

 broad statements of the above kind, which may require to be 

 modified by future discoveries. 



Now, the tendency of all the later results of Palaeontology is 

 to show that some of the higher types of life appeared on the 

 earth a good deal earlier than was formerly supposed. Thus 

 the discovery of the jaw-bones of small mammals (possibly 

 marsupials) in the Purbeck strata, in 1854, and afterwards in the 

 Stonesfield slate (both of Jurassic age), came as a surprise to 

 most geologists. Again, it is not long since birds were believed 

 to have come into existence only in Tertiary times : now we 

 have the Jurassic bird Archaeopteryx (see p. 212), and Professor 

 Huxley has recorded his opinion that some of us may live to see 

 a fossil mammal of the remote Silurian age ! It is, therefore, 

 only prudent for geologists to be on their guard against assuming 

 that all the Secondary mammals were of low types and few in 

 numbers, as might be inferred from the phrase " Age of Mammals." 

 That mammals, however, developed vigorously in many directions 

 during the Tertiary era cannot be doubted. So, far, then the 

 expression conveys important truth ; but in science, as in other 

 things, the "unexpected" often happens, so it is better to be 

 prepared for surprises. 



It would be impossible within the limits of a single chapter to 

 give an account of all the leading orders of Tertiary mammals. 

 We must therefore limit our present remarks to two or three, 

 or more, reserving others for future chapters. 



The discovery, in the early part of the present century, of the 

 rich treasures embedded in the Tertiary strata of the Paris basin, 

 and the consummate skill with which they were interpreted and 

 restored by the immortal Cuvier, gave a very great impulse to the 



