The Lcess and its Fossils 209 



rancre from those which are much smaller and more slender 

 than the fossils, to those which are somewhat larger. The 

 present distribution of this species is through the Northern 

 States to Hudson Bay. 



Limmva liumUii, Say. Not uncommon. Fossils from 

 Johnson and Scott counties, Iowa, and Lancaster county, 

 Nebraska closely resemble rather large recent specimens from 

 Johnson county, Iowa. These have an elevated spire, very 

 convex whorls', and rather small, regularly rounded aperture. 

 This form grades into the following. This exceedingly vari- 

 able species ranges from Kansas to Lake Superior and 

 eastward. 



Limium humilis farva. Lea. This occurs commonly in the 

 Lcess with the two preceding species, and is more abundant 

 than either of them. There is much variation in each set, 

 some of the specimens being very slender, with small aperture 

 and very convex whorls, while others approach the typical 

 L. humhis (\\x\le closely. The fossils were compared with 

 recent specimens from Iowa City, New York and Michigan. 

 The fossils are more slender, with longer spire and smaller 

 aperture. 



Phvsa sp? Rare. Fossils from Lancaster county, 



Nebraska, and Johnson county, Iowa are evidently immature 

 shells, and in such condition that the species could not be 

 determined. 



Planorbis farviis. Say. Rare. Fossils from Lancaster 

 county, Nebraska do not differ from recent Iowa and 

 Nebraska shells. The present distribution is throughout 

 eastern North America. 



Pisidium sp? Rare. I'he few valves and fragments 



from Johnson county, Iowa are in such condition that the 

 species could not be determined. 



All of the species in the foregoing list, and with the excep- 

 tion of the first and the last, are air-breathing Pulmonata. 

 With the exception of the last six species (and possibly Site- 



