BRACHIOPODA. 



229 



w 



O 



M 



CO 



w 







o 



s 



S 

 ►3 



t-i 



o 



HH 



O 





w 



H 



H 



►fl 





1-3 







o 













•rj 



> 



E 



> 









i"^ 



3 



fi 







1 



y 





H 



M 



•xi 



o 



fr 



% 



t-' 



3 





w 



H 



w 



M 



§ 



% 



o 



1 



t-' 



1 



r/1 



o 

 H 



3= 

 O 











1 



> 



> 







W 





1 













Sq 



^ 





.a 

 o 





»t3 



H 

 o 



o 

 W 



O 





I ^ 



EL 



I I 



Lower Cambrian. 



Middle Cambrian. 



Upper Cambrian. 



Calciferous. 



ciiazy. 



Trenton. 



Utica. 



Hudson Kivei". 



Clinton. 



Niagara. 



Lower Helderberg-. 



Oriskany. 



Upper Helderber^. 



Hamilton. 



Chemung. 



Waverly. 



Burlington, 



Keokuk. 



St. Louis. 



Kaskaskia, 

 Chester. 



Lr. Coal Measure. 



Middle and Upper 

 Coal Measures. 



Permian. 



Triassic. 



