REPORT ON THE GEOLOGY OF NORTH AMERICA. 



63 



fossils ; and we do accordingly witness a manifest mingling of 

 the races of the two periods, as the following Table will make 

 apparent. 



Table showing the Species common to the Eocene and the 

 Upper Cretaceous Strata, and also the Species common to 

 the latter and the Lower Cretaceous Strata, in Alabama. 



After carefully reviewing, in a tabular form, the relations 

 of the organic remains of our upper secondary group, I find 

 that if we adopt for our data the 102 known species of Testacea 

 and Ecluiiodermata (rejecting the zoophytes), we perceive that 

 14 species are peculiar to the upper cretaceous formation of Ala- 

 bama, and that only two or three of its species are found in 

 the marl formation of New Jersey. We discover, however, 

 that a much larger number are common to the New Jersey 

 deposits, and the Imver limestone formation in Alabama. 



Subtracting the above 14 species, in order to make the 

 comparison between the marl and this latter formation, we 

 have of the two classes mentioned 88 species. Out of these 

 88 species, 39 are peculiar to the marl formation of Jersey 

 and Delaware, 32 to the older calcareous strata, and 17 

 common to the two. These numbers show a want of identity 

 in the fossils of the two regions worthy of notice. The 

 two deposits, the ferruginous sand or marl of New Jersey, and 

 the inferior calcareous strata of the south, are regarded by 

 Dr. Morton as one formation. Though this opinion may 

 very possibly be correct, to establish it in the present state 

 of our data" would be difficult. It is possible, indeed, that 



