IN THE MUD OF THE LEVANT. 123 



Chalk formation of Sicily still exist, and, conse- 

 quently, cannot be wanting in the Tertiary 

 formations, it is evident that no conclusion, as 

 to the geological age of these formations, can be 

 drawn from the similarity or dissimilarity of these 

 forms."* 



This paragraph annuls much of M. Ehrenberg's 

 previous argument ; but as the latter has been far 

 more widely circulated in England than the former, 

 it is desirable that every opportunity of correcting 

 the error should be made available for that pur- 

 pose, and more especially as M. D'Orbigny still 

 appears to hold some similar views, notwithstanding 

 the numerous opposing facts which he has himself 

 brought to light.f Speaking of the study of the 

 Forarainifera, as applied to geology, he remarks, 

 that " as these minute shells are infinitely more 

 common than those of molluscs, the knowledge 

 to be derived from them is so much the more 

 certain, and becomes extremely interesting." And 

 again, after stating his opinion, that different 

 terrestrial zones have their peculiar species, he 



* Silliman's American Journal of Science. Vol. xlvi. p. 297. 



t Mr. Weaver's Abstract of the Memoir of M. Alcide 

 D'Orbigny, on the Foraminifera of the White Chalk of the 

 Paris Basin. Phil. Mag. Vol. xviii. p. 456. 



