U. S. GEOLOGICAL SURVEY 



MOMOGHAPH XVIII PLATE ; 



16 



7 





JL 



/ 



IT 





;, 3 



4' 



h. 



h ■ 



19 ^\ 



^ 



SO 



22 



/ 



^1 



S-3 _-^ 



2* 



-••■v^ , , <^^: 



S? 



^-i 



21 



„ > S 



/-" 



~...^' 



W^ 



PLEURO"rOMID/E AND STROMBID/E OF THE LOWER GREENSAND MARLS. 



