BRACHIOPODA. 



229 



►6 



IS 



o 





O 



o 



cc =: -^ tj 



N 

 O 



»'i — 



>'» ~ 



ts 

 a 



o 



^ 



f 



<4 



o 



O 



-3 



I I 



I 



Lower Cambrian. 

 Middle Cambrian. 

 Upper Cambrian. 



Cliazy. 

 Trenton. 

 Utica. 

 Hudson liiver. 



< I][|I<JU. 

 ^ : -.ir.T. 



I . r Ilcl<Ieilierg. 



Oribkany. 



Upper Heblerbcr^'. 



Hamilton. 



Chcmtuig:. 



Waverly. 



I'.urlin^tnii. 



K'«'i>kuk. 



St. XvOuis. 



Xvaskaskia, 

 Chester. 



Lr. Coal Measure. 



Middle and Upper 

 Coal Measures. 



Permian. 

 Triassic. 



