The Loess and its Fossils. 205 



Papa fcntodon^ (Say) Gld. Rare. Fossils from Lancaster 

 county, Nebraska are of the same size and form as recent 

 shells from Iowa and Nebraska. The species now ranges 

 from Minnesota to Texas. 



Pupa armifera, Sa}'. Not common. Recent specimens 

 from all of the states from Nebraska to New York show 

 much variation* in size and form. The range of variation 

 would easily include the fossils from Johnson county, Iowa, 

 and Saunders county, Nebraska. The fossils from the latter 

 locality are more cylindrical than those from the former, but 

 not more so than many of the recent shells. 



This species occurs now from Dakota to Kansas, and 

 eastward. 



Pupa decora, Gld. This species, which the writer formerly^ 

 identified as Pupa blandi, Morse, is very abundant in the 

 Loess. Fossils from Dubuque, Scott, Muscatine, and Johnson 

 counties, Iowa, and Lancaster, Cuming, and Saunders coun- 

 ties, Nebraska were carefuU}' studied. These present some 

 variation in form and size, and also in the number of parietal 

 teeth, some specimens exhibiting two, others only one fold, 

 but this variation may be observed in large sets from any of 

 the localities cited. 



The species belong to the northern portion of the continent, 

 rantjing from New York to ihe Great Slave Lake. 



Pupa niHsconim, L. Quite common. Fossils from Scott, 

 Muscatine, Johnson, and Polk counties, Iowa; and Lancaster 

 and Cuming counties, Nebraska were compared with recent 

 specimens from Anticosti Island, Gulf of St. Lawrence. The 

 fossils from Scott county, Iowa, and Lancaster county, 

 Nebraska are rather more slender than the recent shells, 

 while those from the remaining localities are precisely like 

 them. 



This species is now found on this continent in Maine, New 



I See "The Am. Geologist." Vol. I., No. 3. March, i8SS. 



