IOWA CITY LOESS. 199 



grounds, under logs, etc. Rare in the loess at Iowa City, 

 but very common in the western loess at Council Bluffs, 

 Iowa. 



*BlFIDARIA HOLZINGERI (Stcrki) . 



Quite common under stones, etc. on exposed hillsides. 

 Rather rare in western loess. 



**Bifidaria pentodon (Say) Stcrki. 



Quite common on rather open rocky slopes, sometimes 

 on lower grounds, under stones, etc. As a fossil this 

 species is widely distributed, and in this locality is very 

 common. 



*Bifidaria CURVIDENS (G/d.) Stcrki. 

 Not uncommon. It is rare in the loess of the west and 

 south, but has not been found fossil at Iowa City. 



*BiEidaria corticaria (Say) Stcrki. 



Common in a few restricted localities among the roots of 

 tufted grasses, etc. growing on exposed rocky slopes. Not 

 found in the local loess, but reported from Des Moines by 

 Keyes, from Muscatine by Witter and from Illinois by 

 Leverett. It is not rare in the loess of Natchez, Miss. 



*Poeygyra LEAi (Ward) Pils. 



Found here under sticks, etc. on slopes near a prairie 

 swamp. Also more rarely on scantily wooded slopes. 

 Rare in the loess of the west, etc. 



*Succinea avar a Say. 



Not rare on more or less exposed rocky slopes. This is 

 the small, typical form which is now found on low grounds. 

 The same form occurs abundantly as a fossil, being one of 

 the most characteristic species of the loess. It occurs in 

 all the fossiliferous exposures near Iowa City, being the 

 only fossil found in some of them. 



**VlTREA INDENTATA (Say) PUs. 



Not rare on rocky slopes. This, and the following 



