BULL. GEOL. SOC. AM 



VOL. 20, 1908, PL. 



Figure 1.— Looking almost East 

 (a) Kansan ; (h) irregular line of contact, showing folding; (c) Aftonian, more or less 



disturbed 



Figure 2. — Looking East of South 



(a\ Kansan; (6) contact line; (c) tilted Aftonian gravel, evidently pushed into an 

 almost vertical position by (a) 



McGAVERN PIT, SOUTH OF MISSOURI VALLEY, IOWA 



