IOWA CITY LOESS. 205 



**Succinea obliqua Say. 



Very common under leaves, etc. on timbered alluvial 

 bottom-lands. Westward the species frequently appears on 

 higher grounds. Quite common as a fossil. 



*Carychium exiguum (Say) Old. 



This species is common in damp places on rather low 

 grounds, under logs, etc. No local fossil specimens have 

 been found, but the species is rare in the western loess. 



*Pomatiopsis lapidaria (Say) Try. 



Locally common with Pyramidula striatella. This 

 species, like Helicina occulta is a gill-bearing mollusc, yet 

 it is strictly terrestrial in its habits. The author has col- 

 lected living specimens in widely separated sections of the 

 State, and found the habitat uniformly the same. Not 

 found in the local loess, but reported from Memphis, 

 Tenn.,* from Missouri t and from Arkansas.! 



While the species of this group are more common on lower 

 grounds, most of them occasionally appear on higher 

 slopes. Thus Polygyra multilineata (medium sized), 

 Bifida ria contract a ', Vitrea hammonis, Pyramidula stria- 

 tella and Succinea obliqua are very common on a rather 

 scantily wooded, rocky, steep slope in Iowa City at an 

 altitude of from twenty-five to seventy-five feet above the 

 Iowa river. Most of these species also occur sparingly at 

 higher altitudes in the western part of the State. Bifida ria 

 contracta is so common in such situations in all parts of 

 the State, that it might well be classed in group [b) . 



d. Species of mud-flats, edges of swamps, etc. 



ZONITOIDES NITIDUS (Milll '.) St. 



This species is locally not uncommon under sticks and 



* James M. Safford: Geol. Tenn., p. 434; 1869. Reported as Amnicola. 

 f G. C. Swallow: Geol Sur. of Mo., vols, i and ii, p. 215. Also reported 



as Amnicola. 

 X R. E Call: Rep. Ark. Geol. Sur., vol. ii, pp. 166, 167 and 179. 



