132 PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY 



AGE DETERMINATION OF FAUNAS 

 BY E. 0. ULRICH 



METHODS OF CREATING POPULAR INTEREST IN EXHIBITS OF FOSSILS 



BY E. S. RIGGS 



Upon the completion of the symposium, the reading of papers on Uie 

 regular program was resumed. 



PKESENTATION OF PAPERS 



In the absence of the author, the following was read by the Secretary: 



DECREASING SALINITY OF THE PLEISTOCENE CHAMPLAIN SEA GOING 

 SOUTHWARD, AS SHOWN BY THE CHARACTER OF THE FAUNA, WITH 

 A BRIEF DISCUSSION OF THE PLEISTOCENE FAUNA OF THE HUDSON 

 VALLEY AND ITS SIGNIFICANCE i 



BY WINIFRED GOLDRIKG 



{Abstract) 



Recent collecting in the Pleistocene deposits of ttie Cliamplain and Saint 

 Lawrence valleys has called attention to the fact that going southward there 

 is a marked change in the fauna, similar to that seen in the Baltic Sea today. 

 Careful study of this fauna and comparison with the conditions found in the 

 Baltic and elsewhere has led to the conclusion that the character of the 

 Champlain fauna is due in large part at least to decreasing salinity southward 

 in the waters of that time. 



The Baltic Sea shows a very striking decrease in salinity eastward and. in 

 a large way. the responses of the fauna to it. As the salinity of the water 

 decreases from that normal for sea-water, the fauna changes from one typic- 

 ally marine to one in which only a few marine groups are represented and 

 finally to a fresh-water fauna. Another striking change has been noted in the 

 character of the Baltic fauna which may likewise be correlated with the varia- 

 tion in salinity: As the stenohaline forms disappear entirely, euryhaline forms 

 become dwarfed. Modifications due to changes in the salt content of water 

 are not confined to invertebrates alone. The dwarfing of fishes in the Baltic 

 has been noted above ; also the fishes of the Black Sea in their paucity of 

 specific forms (compared with those of the Mediterranean) and marvelously 

 great number of individuals are very indicative of the estuarine character of 

 its waters. 



A careful list, with localities, has been compiled of the Pleistocene inverte- 

 brate species collected by the writer and also all those reported by others in 

 various publications, and these have been tabulated to show the distribution 

 of the species from the sea (Labrador) to the southernmost locality (two miles 



^ This paper will appear in full in a New York State Museum Bulletin. 



