BULL. GEOL. SOC. AM. 



07, PL. 2 



_}JPPeFi RAPins 



ui 



LIMESTONE 



SANDSTONE. 



Fort Snelling- 



Fjg. I 



SAINT -PETES; •:•.■.•■:•. 



■ •SANDSTONiE- 



SHAKOpiT-JirdoMrf 



Figure 1 is a section across tlie Mississipiji river near t 



