BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 14, pp. 153-176, PLS. 14-15 APRIL 30, 1903 



MARL-LOESS OF THE LOWER WABASH VALLEY^'- 



BY M. L. FULLER AND F. G. CLAPP 



{Read before the Society January S, 1903) 

 CONTENTS 



Page 



Introduction i 153 



Comparison of the common and marl-loess types 154 



Common loess 1 54 



Description 154 



Distribution 156 



Marl-loess 156 



Distribution and range 156 



Color 158 



Composition 158 



Stratification 159 



Fossils 160 



Terraces 162 



Discussion of evidence. 163 



Origin of the marl-loess 166 



Manner of deposition 166 



Distribution of the marl-loess 167 



Cause of the ponding 168 



Derivation of the materials 168 



Derivation of the loess of the common type 169 



Evidences pointing to aqueous accumulation of part of the loess 169 



General statement 169 



Large pebbles 169 



Loess-covered till plains 169 



Loess-covered aqueous deposits 170 



Silt flats 170 



Silted divides. 170 



Probable conditions of accumulation 171 



Probable eolian derivation of the main loess accumulatioiid 172 



Conclusions 173 



References to literature 174 



Introduction 



The descriptions and conclusions herewith presented are based on 

 observations made during the course of the geologic mapping of six 



* Published by permission of the Director of the U. S. Geological Survey. 

 XXII— Bull. Geol. See, Am., Vol. 14, 1902 (153) 



