128 



THEORY OF SUDDEN EISE OF 



[Ch. VII. 



Should he 



pretend to define the date of the convulsion with 



reater precision, and decide that the earthquake 



must 



Greek and before the Gothic period 



in his reasoning would be too palpable 



have occurred after the 



that is to say, when the Boman style was in use, the fallacy 



to escape detection 

 for a moment. 



Yet such is the nature of the erroneous induction of which 

 I am now treating. For as, in the example above proposed 

 the erection of a particular edifice is an event scarcely ever 

 coextensive in time with the whole period of a certain 

 style of architecture to which it conformed, so the de- 

 position of chalk or any other set of strata may have been 

 effected in a small part of that geological epoch to which 

 the species of fossils characterising such strata may belong 



It is almost superfluous to enter into any further analysis 

 of the theory of parallelism, because the whole force of the 

 argument depends on the accuracy of the data by which the 

 contemporaneous or non-contemporaneous date of the ele- 

 vation of two independent chains can be demonstrated. In 

 every case 



equivocal, because he has not included in the possible interval 

 of time between the deposition of the deranged and the 

 horizontal formations, part of the periods to which each of 

 those classes of formations are referable. Even if all the 

 geological facts, therefore, adduced by the author were true 

 and unquestionable, yet the conclusion that certain chains 

 were or were not simultaneously upraised is by no means a 

 legitimate consequence. 



M 



In the third volume 



my 



which appeared in April 1833, I controverted the views of 

 M. de Beaumont, then just published, in the same terms as 

 I have now restated them. At that time I took for granted 

 that the chronological date of the newest rocks entering into 

 the disturbed series of the Pyrenees had been correctly 

 ascertained. It now appears, however, that some of the 

 most modern of those disturbed strata belong to the num- 

 mulitic formation, which are now regarded by the majority 

 of geologists as Eocene or lower tertiary. 



Perhaps a more striking illustration of the difficulties we 



