BULL. GEOL. SOC. AM 



VOL. 20, 1908, PL. 3 



Figure 1. — View in railway Cut 



ar Thayer 



Showing a moderately large mass of Aftonian gravel, with smaller "sand 

 ders" from the same formation, incorporated in the Kansan drift 



m 





r 



> 



Figure 2. — The McGayern gravel Pit near Missouri Valley 



Showing (A) a very large '"sand boulder" of Aftonian gravel, crushed, faulted, and 

 deformed, and (K) the face of a mass of Kansan drift, the agent through which the 

 crushing was accomplished. 



GLACIAL PHENOMENA NEAR THAYER AND MISSOURI VALLEY, IOWA 



