BRACHIOPODA. 



336a 



a 



H 





!3- 











rf 



c* 









cr 



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a 







■-( 















2 



m 



?a 



Pi 



3 



CLCR5 



V* 



(D 





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CD 



m 



n 









a 









>-; 



a 



CH! 





o 



P- 



d 





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-d p- 



g' 



OtJ 



a 



fD 

 O 





o 



o 

 a 





S 



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5' 



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3 



o 

 o 



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B 



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Q 



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» 



p^ 



13 



C 





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(6 



m 



( 



CD 



o 



at? 



so 



CD 



H3 







o^ 



CD 



hj 





P' 



S 







(X? 



CD 



6 



o 



d 



J:^ 



P- 



Ss 



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g 



n 



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an? 



3 



(5 



o 



9 



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p 



It 



g- 



N 



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to 



P 



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cr 



cc 







O 



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K 



o 







t^ 



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H 











t-' 



2 



g 



o 



o 

 t-l 



td 



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. 





J> 



s 



CD 



• 



' 



o 



i 



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CO 





tr] 



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CD 



Lower Cambrian. 



Middle Cambrian. 



Upper Cambrian. 



Calciferous. 



Cliazy. 



Trenton. 



Utica. 



Hudson River. 



Clinton. 



Niagara. 



Lower Helderberg. 



Oriskany. 



Upper Helderberg. 



Hamilton. 



Chemung. 



Waverly. 



Burlington. 



Keokuk. 



St. Louis. 



Kaskaskia, 

 Chester. 



Lr. Coal Measures. 



Middle and Upper 

 Coal Measures. 



Permian. 

 Triassic. 



