BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 21, pp. 119-140, PL. 2 March 31, 191o 



EVIDENCE THAT THE FOSSILIFEEOUS GEAVEL AND SAND 

 BEDS OF IOWA AND NEBRASKA ARE AFTONIAN^ 



BY B. SHIMEK 



{Presented hy title before the Society December 30, 1909) 



CONTENTS 



Page 



Previous discussions , 120 



Importance of the Aftonian mammalian fauna 120 



Correlation with other deposits 120 



Evidence of climatic conditions 120 



Significance of the Aftonian molluscan fauna. 121 



The Aftonian mollusks 121 



Comparison with modern mollusks 122 



Evidence of climatic and surface conditions 123 



Importance of exact determination of Aftonian horizon 123 



Evidence that beds are Aftonian 124 



General characteristics of the Aftonian 124 



Composition and structure 124 



Distribution of fossils 125 



Stratigraphic relation, Pleistocene section 125 



Detailed description of fossiliferous sections 126 



Order of treatment 126 



1. Akron section 126 



2. Searles section 127 



3. Anderson section 128 



4. New Woodward section 128 



5. Weniger pit 129 



6. Elliott pit 129 



7. Ordway pit 130 



8. Ordway well 131 



9. Griflin well 131 



10. Wilkenson well , 132 



11. Hawthorn pit 132 



12. McCleary pit 132 



13. County line exposure 132 



14. Peyton pit 133 



15. Wallace pit I34 



16. Robinson pit I34 



1 Manuscript received by the Secretary of the Society December 30, 1909. 



(119) 



