•120 EEPORT OF NATIONAL MUSEUM, 1904: 



the physical conditions of the ocean can not be presumed to have remained the same 

 over a wide extent of surface. Under such circumstances, absolute parallelism is not 

 to he sought for or expected. Calcareous deposits, as would naturally be supposed, 

 have beenfoundto be more persistent and more uniform in the character of their fossil 

 contents; hut these, over some portion of their extent, have often been invaded by 

 argillaceous and arenaceous sediments, and the fauna is found to be in a greater or 

 less degree influenced by such circumstances. 



The following table was given, showing the subdivisions of the 

 Paleozoic series in New York: 



1. Potsdam sandstone. 



2. Calciferous sandstone. 



Upper sandstone of Wisconsin and [Minnesota similar to the Potsdam 

 sandstone. 

 .">. ( hazy limestone. 



4. Bird's-eye and black River limestone. 



5. Trenton limestone. 



Galena or lead-bearing limestone of Wisconsin, Iowa, and Illinois not rec- 

 ognized at the East. 



6. Utica slate. 



7. Hudson River shales. Included in the Hudson River group. 

 s. ( iray sandstone. 



9. Oneida conglomerate. 



10. Medina sandstone. 



11. Clinton group. 



12. Niagara group, coralline limestone of Schoharie. 

 l.">. Onondaga salt group. 



14. Tentaculite or water limestone 



15. Pentamerus limestone. 



18. Delthyris shaly limestone. 

 17. Encrinal limestone. 

 IS. Upper Pentamerus limestone. 



19. Oriskany sandstone. 



20. Cauda-galli grit. 



21. Schoharie grit. 

 nn ~ , ,. , » {-Upper Helderberg group 



22. Onondaga limestone. | ' * 



23. Corniferous limestone. 



24. Marcellus shale. 



Lower Helderberg group 



25. Hamilton group.. 



.,„ ™ n ,. -Hamilton group. 



2b. Tally limestone. e l 



27. Genesee slate. 



28. Portage group. 



29. ( Ihemung group. 



30. Sandstone and shale of the Catskill Mountains. 



31. (iray and yellow sandstone. 



32. Greal Carboniferous limestone. 



The following was given to show the equivalency of the Cliff lime 

 stone with the New York group: 



