352 LIFE OF THE PLEISTOCENE 



Chamberlin and Salisbury 28 list a number of mollusks from the Driftless 

 Area. The species with their localities are tabulated below : 

 Savanna, Illinois. 



Pyramidula cronkheitei anthonyi Succinea avara 



Oreohelix iowensis " obliqua 



Along some of the tributaries of the Mississippi there are loess-like deposits 

 which are said 28 to be younger than the true loess referred to above. The 

 exact correlation of these deposits seems difficult, but as one locality (Jefferson) 

 affords a characteristic post-Iowan mollusk (Oreohelix) they are included here, 

 tho some may be as late as Post- Wisconsin time. 



Terraces at Galena, Illinois. 



Succinea avara Succinea obliqua ( = oialis) 



Leucochila fallax Planorbis parvus 



Pyramidula cronkhitei anthonyi Galba humilis modicella 



20 feet above Apple River, Township 27, JoDaviess County, Illinois. 



Pyramidula cronkhitei anthonyi Pupilla muscorum 



Higher terraces, Bridgeport, Crawford County, Wisconsin, near mouth of 

 Wisconsin River. 



Succinea avara Sphyradium edenttdum alticola 



" obliqua ( = Vertigo simplex) 



Pyramidula cronkhitei anthonyi Galba humilis modicella 



Section 34, Ellenton Township, Grant County, Wisconsin. 



Succinea avara 



Southwest quarter section 20, Jefferson, Clayton County, Iowa. 



Succinea avara Pyramidula cronkhitei anthonyi 



" obliqua Pupilla muscorum 



Oreohelix iowensis Sphyradium edenttdum alticola ( = Vertigo) 



Vallonia palchella Galba humilis modicella 



Galena, Illinois, 135 feet above Galena River. 



Helicodiscus parallelus Succinea avara 



" obliqua 



Southwest quarter section 26, Bloomington, Grant County, Wisconsin. 



Succinea avara 



East of Prairie du Chien, Wisconsin, on the heights at 425 feet above the 

 Mississippi River. 



Succinea aiara Galba humilis modicella 



28 Driftless Area, pp. 285-286. 



