BULL. GEOL. SOC. AM. 



VOL. 23, 1912, PL. 9 



Figure 1. — Ixdiax Mounds west of Granite, Iowa 

 On bench, or terrace 



Figure 2. — Section of Terrace near north line of Section 17, Township 99 



north. Range 48 west 



a, Nebraskan ; t, gravel and bowlders 

 FEATURES OF THE BIG SIOUX RIVER TERRACES 



