U.S. GEOLOGICAL SURVEY 





LEGEND 



Carboniferous 



/-J.T \ / Granih 



c'.ss. Quar/zihc sandstone 

 grsA Green shale 

 r.sh. /fee/ shale 



/?//. Hyo/i/hellus 



yerf. Perh'ca/ 

 cong/. Cong/omerate 



r./. fft 

 tril. Tr 

 h. H } 



SK| 



CAMBRIAN FO SSI 



SOUTHWEST ( 



