March, 1907.] Fossil Land and Fresh Water Mollusca 



III 



At the same time, the recent mollusca of that vicinity should 

 be collected carefully for comparison. It must be remembered, 

 however, that most of the surface of north-western Ohio is now 

 under conditions radically different from what they were only 

 fiftv to seventy years ago. It is safe to say that there are at 

 present hardly more than five per cent of the mollusca living of 

 what there were originally, that is, of individuals. Very probably 

 also, the number of species has considerably decreased. 



The following is a list of the mollusca found, with a few notes. 

 All of the species are now living in Ohio. 



1. Gastrodonta Ugera, Say, one specimen. 



2. Zonitoidcs arboreiis Say, one specimen. 



3. Hyalina radiatula Alder, one specimen. 



4. " indentata Say, one specimen. 



5. " (or Zonitoides) Iceviusctila Sterki, a western species having the 

 eastern limit of its recent distribution in Ohio, so far as known. 



6. Circinaria concava Say, several specimens. 



7. Polvgyra profunda Say, several. 



8. " multilincata Say, several. 



9. " albolabris Sa^^ one, large. 



10. " zaleta Say (exoleta), a few. 



11. " claiisa Say, one fine specimen. 



12. " mitchclliana Lea, one specimen. 



13. " thyroides Say, a few. 



14. " d'evata Say," several, the commonest of all, except No. 25. 



15. " fraudidcnta Pilsbj^r ("fallax Say" of authors), two. 



16. " inflecta Say, two. 



17. " liirsnta Say. 



18. Patula (Pyramidula) solitaria Say, large, several. 



19. " " altcrnata Say, a few. 



20. " " striatella Anthony. 



.21. Bifidaria contracta Say, one. (Pupa contracta Say.) 



22. Sitccinca avara Say, one, rather large. 



23. " rctusa Lea, one. 



24. Phyra sp., one specimen, broken to fragments. 



25. Pomatiopsis lapidaria Say, coinmon. 



26. Pisidium- compressum Prime, two left valves. 

 _27. " fallax Sterki, one valve. 



Of Unionid(£, numerous fragments were found, but all too 

 small to be identified; most of them were near the top layer. 

 A large part of the shells were more or less damaged; few^ in 

 perfect condition. 



Fossil land and fresh water shells should be collected wherever 

 found. But caution is necessary: they should not be cleaned 

 more than required for identification, and under no condition 

 •should they be washed; water will damage them, especially 

 will it loosen the outer layer of shell substance in the aperture, 

 containing the characteristic parietal teeth of the Polygyrae etc. 



New Philadelphia, Ohio. 



