of the C/tdlk Formation. 257 



view, and to compare them according to his own idea of them 

 with the existing state of science, but also to ehicidate the 

 conchtsions which directly and necessainly result from them. 

 This additional task is generally very difficult, sontietimes lead- 

 ing to the discovery that what had been supposed new was 

 not so, or not of sufficient importance for such an extended 

 investigation ; sometimes rendering a fresh and more pro- 

 found examination requisite, or misleading to an evident ex- 

 aggeration of the facts discovered, and to conclusions which 

 they do not justify, and is therefore very frequently avoided 

 from motives of fear or convenience. To leave this to others 

 lightens indeed the labour of the task ; but this alleviation, 

 at the same time, lessens the value of isolated observations, 

 and throws a doubt upon the care employed in making the 

 comparison. 



Along with the general view of the facts advanced, I have 

 also aimed at forming comparisons and conclusions, not in 

 order to veil any erroneous view of the facts, but to render it 

 the more conspicuous where it had gained ground ; and, on the 

 other hand, to render the truth discovered more striking, and 

 thus to awaken a more general and active interest for this 

 kind of inquiry, 1 shall only draw such conclusions as are 

 most obvious, since the further we depart from actual observa-* 

 tion, the more we deviate into the field of uncertain specula- 

 tion, which, when constructive, instead of being completive 

 nearly, becomes the very opposite of philosophical inquiry, 

 and is just as feasible for anybody as for the philosopher him- 

 self. 1 would desire, that my conclusions should always be 

 less rather than more than the observations might warrant 

 me to draw. 



1. There are numerous animals of the chalk formation 

 which are still found living, and precisely such as do not, 

 either from great variation of form within generic limits, or 

 from the simplicity of their exterior, leave any uncertainty in 

 determining theu' specific difference. 



2. Of the animal forms which constitute the greater mass 

 of the white chalk, those which preponderate in number of 

 individuals are identical with living species ; and hitherto all 

 the principal species which form the rocks, have been observed 



