A COMPARISON BETWEEN THE ANCIENT AND MODEEN 

 MOLLUSC AN FAUNA OF OMORI. 



Some interesting facts are revealed in studying the remains of the animals 

 •which form the bulk of these deposits in Denmark, New England, Florida and 

 Omori. 



These facts show the following : 



First : that a change has taken place in the relative abundance of individuals 

 of certain species. 



Second : that a change has taken place in the relative size of certain species. 

 Third : that a change has taken place in the relative proportions of the shells 

 of certain species. 



Fourth : that a change has taken place in the extinction of certain species. 

 The modification in the relative size and proportions of certain species is pro- 

 found, and would seem to indicate, either that species vary in a much shorter 

 time than had been supposed, or else that deposits presenting these peculiarities 

 have a much higher antiquity than had before been accorded them. 



We quote the following from Lubbock's " Prehistoric Times " page 231, as 

 bearing upon this subject. In the Danish Mounds the four most abundant 

 species of mollusks are : 



The oyster, Ostrea edulis L. 



The cockle, Cardivm edule L. 



The mussel, Mi/tihis edulis L. 



The periwinkle, Litoriiia Utorea L. 



All four of which are still used as food for man. Other species occur more 

 rarely, namely,— 



Nassa reticulata L. 

 Buceiuum undatum L. 

 Venus pitllastm, Mont. 



