296 



LIFE OF THE PLEISTOCENE 



Phidium punctatum 

 'i compression 

 " variabile 



" species 

 Carychium exiguum 



exile} 

 Succinea avara 

 Vallonia perspectiva 



Strobilops virgo 

 Bifidaria contracta 

 " corticaria 

 " hohingeri 



Vitrea hammonis 



Pyramidula cronkhitei anthonyi 

 Helicodiscits parallellus 



Pisidium punctatum 

 " compressum 

 " variabile 

 " virginicum 

 " species 



Succinea avara 

 Vallonia costata 

 Bifidaria contracta 



Bifidaria hohingeri 

 " armifera 

 Vertigo elatior 



" tridentata 

 Zonitoides arborea 

 Vitrea hammonis 



" indentata 

 Zonitoides minuscula 

 Pyramidula cronkhitei anthonyi 



altemata 

 Helicodiscits parallelus 

 Polygyra hirsuta 



" species 



Crustacea 



Cypris 

 Ostracod 



From near Bolton, Hershey reports Pisidium abditum? 



d. Illinoian Loess 60 * 



Loess deposits cover much of the Illinoian drift sheet especially along the 

 banks of the large rivers, such as the Mississippi, Rock, Illinois, Kaskaskia 

 and Wabash. As in Iowa, the loess includes two divisions, an earlier (Illinoian) 

 and a later (Iowan). Possibly some of the loess adjoining the Wisconsin till 

 may be of post- Wisconsin age. In Adams County, 61 in a coal boring near Coats- 

 burg, the relation of the loess to the underlying strata is well shown. 



Soil and yellow clay (Iowan loess) 6 feet 



Gray or ashy clay (Illinoian loess) .' 4 " 



Yellow till, becoming blue near bottom (Illinoian drift) 10-15 " 



Blue-gray till (Illinoian) 70-75 



Black soil (Yarmouth) 2\4 " 



8oa See Ante page 251 for the result of recent stud-es on the great loess deposits of the 

 Mississippi valley. 



61 Leverett, Illinois Glacial Lobe, p. 716. 



