12 



ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 461 



X. 



WISCONSINAN 



IL LINOIAN 





\v RANGE 



MOLLUSCAN >v 

 SPECIES X. 





STAGE 



STAGE 





KANSAN 

 STAGE 



z 

 < 



o 

 tr 

 o 

 u. 



Q 



o 

 o 



UJ 



o 

 <I 



(/) 

 CD 



in 



FARMDALIAN 

 AND ALTONIAN 

 SUBSTAGES 



JUBILEEAN 

 AND MONICAN 

 SUBSTAGES 



z 

 < 



UJ 



o 

 < 



1- 

 c/> 



CD 

 C/> 



Gastrocopta holzingeri 

















Gastrocopta procera 

















Helisoma trivolvis 

















Planorbula armigera 

















Pupoides albilabris 

















Sphaerium occidentals 

















Stenotrema leai 

















Triodopsis algonquinensis 

















Tri odops is fosteri 

















Vertigo milium 

 Helisoma antrosa 



















Mesodon thyroidus 

















Pisidium caseratanum 

















Pisidium nitidum 

















Pisidium var labile 

















Sphaerium striatinum 

















Stenotrema fraternum 

















Vallonia parvula 

 Allogona profunda 





















Amni cola leigh toni 

















Amni col a lustrica 

















Anguispira kochi 

















Triodopsis altonensis 

















Triodopsis hubrichti 

 Aplexa hypnorum 

 Lymnaea ex His 

 Acella haldermani 































Succinea avara 

















Vertigo briarensis 

 Armiger exigua 



















Deroceras aenigma 

















Helicodiscus singleyanus 

 Lymnaea palustris 

 Gastrocopta armifera 

























Gastrocopta contracta 

















Lymnaea obrussa decampi 

















Pisidium compress urn 

















Pomatiopsis scalaris 

















Punctum minutissimum 







'•!•!■!■!■!•'•!•!•!'!■!•!■!•!•! 











Fig. 4 - Range of Pleistocene 



