94 PHILOSOPHY OF ZOOLOGY. 



those in the contiguous beds, and that the same bed, in its 

 course through several miles, may be easily recognised by 

 its petrifactions. WERNER, in attempting to generalise this 

 observation, announced it as his opinion, " That different 

 formations can be discriminated by the petrifactions they 

 contain *." When it is considered that a particular bed of 

 rock can seldom be traced for many miles, the assertion 

 that it may, through this extent, be characterised by its pe- 

 trifactions, is neither in opposition to observation, nor the 

 laws which regulate the distribution of animals. But when 

 it is meant to be understood, that the same group, or for- 

 mation of beds, (though occupying the same position with 

 respect to other groups), however remotely connected in 

 geographical position, contain the same petrifactions, it be- 

 comes necessary to state, that such an opinion is unsupport- 

 ed by observation, and inconsistent with the laws which at 

 present influence the distribution of animals. There is no 

 proof of the same fossil species being found in the same 

 formation at the equator, and in temperate and cold re- 

 gions ; and when genera only are referred to, the reason- 

 ing becomes exceedingly vague, and apt to mislead. The 

 celebrated VON BUCK, a pupil of WERNER, in his Travels 

 through Norway, gives us an example of the Wernerian 

 rule, by stating, that Orthoceratites characterise exclusively 

 the transition limestone formation )-. There is, however, 

 no evidence, that the species of Orthoceratites were here 



* See note by Professor Jameson to Cuvier's Theory of the Earth, Edin- 

 burgh 1813, p, 225. 



f " How great was my joy when, at the steep falls of Aggers Elv, above 

 the lower saw -mills, I discovered the Orthoceratites, which so particularly 

 distinguish throughout all Europe this formation (Transition Limestone), and 

 this formation alone." English Trans, p. 47. 



