560 E. O. ULRICH REVISION OF THE PALEOZOIC SYSTEMS 



sediments of Silurian age in western Tennessee, north Arkansas, Okla- 

 Suggested Sequence of Niagaran Deposits in North America 



Western Tennessee, north Arkansas, 

 and Oklahoma 



Middle and north- 

 ern Appalachian 

 and Allegheny 

 regions 



Wisconsin 



Cayugan 



Decatur 









McKenzie 





s 



1 



Q 



Louisville 











Guelph 



Bob and Beach rivers 











Racine 



Dixon 







Lego 





Waukesha 



Waldron and Laurel 











Mayville 



o 



.s 



6 



Osgood and upper St. Clair 



Rochester 







Williamson 





St. Clair (typical) 



Wolcott 







Sodus 





Brassfield 





? Iron Ridge ore bed 



homa, Kentucky, and southern Indiana are southern in origin and in- 

 vaded the continent froni the Gulf of Mexico; (2) that either the whole 



