40 CREiTACEOUS PALEONTOLOGY. 



ANALYTICAL DISCUSSION Olf THE CLIFI'WOOD FAUNA. 



The composition of the entire fauna of the Cliffwood clays, as 

 exhibited in the five localities recognized, is shown in the above 

 table, with the distribution of the recognized species in the other 

 Cretaceous formations of New Jersey and a record of their 

 occurrence in the Ripley Group of the Southern States. The 

 essential features of this table, in so far as the number of species 

 in the various formations is concerned, may be shown as follow : 



CLIFFWOOD, 43 



Merchantville, i6 



Woodbury, ^ 21 



Marshalltown, 7 



Wenonah, 19 



Mt. Laurel-Navesink 4 



Red Bank 8 



Tinton 2 



Ripley Group, etc 22 



Of the total 43 species recognized in the Cliffwood fauna 14, or 

 32 per cent., haye not been recognized in any other formation in 

 New Jersey, so that only 29 species have a wider range within the 

 State. Of the 22 species which are known to occur also in the 

 Cretaceous beds outside of Ncav Jersey, chiefly in the Ripley 

 formations of the Southern States, all but three are also included 

 in the 29 species which have a wider distribution in the State, the 

 exceptions being Ostrea cretacea, Ostrea congesta and Trigo- 

 narca triquetra. 



In passing from the Cliffwood to the Tinton in this table a 

 reduction in the number of species in common to the formations 

 is noticeable, as might be expected, the reduction being from the 

 total number of species in the Cliffwood to only two in the Tinton. 

 A highly important fact, however, in the data exhibited by this 

 table is that the reduction in the number of co^mmon species in the 

 successive formations is not regular, there being a distinct alter- 

 nation, the greater number of common forms being present in the 

 Woodbuiry, Wenonah and Red Bank. This distinct alternation 

 is not accidental, nor is it due to the fact that the entire known 



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