154 NATURAL HISTORY. 



des Environs de Paris.' This work may be looked upon 

 as the most important contribution which had been made 

 up to that time to the study of the Tertiary series of rocks. 

 It was principally, however, by the study of the organic 

 remains contained in these strata that Cuvier has made 

 himself famous. 



Long controversies had been carried out among the 

 earlier naturalists as to whether ' fossils ' were really the 

 remains of animals at all many holding that they were 

 merely peculiar mineral structures, formed by a kind 

 of 'plastic virtue' in the earth itself. The notion, how- 

 ever, that fossils were merely lusus natures had been 

 given up before Cuvier's time by most of the leaders of 

 science ; though it was still generally held that fossils were 

 the remains of the animals and plants now in existence 

 upon the globe. It had, of course, often been pointed 

 out as early as the time of Hooke and Ray, in fact 

 that many fossil shells were quite unlike any similar shells 

 now existing ; but it had been common to meet this by 

 the argument that our knowledge of living animals was 

 still very imperfect, and that very probably further 

 investigations would show that the fossil forms which 

 were supposed to be extinct, were really still living in 

 some hitherto unexplored region. This last argument 

 was, however, rendered quite untenable by the discovery 

 of the remains of numerous unknown quadrupeds, often 

 of large size, in the Tertiary beds round Paris ; since, even 

 in the beginning of this century, it was certain that no 

 noteworthy discovery of large living Mammals was likely 

 to be made in any of the less known portions of the 

 earth's surface. 



