IOWA CITY LOESS. 203 



slopes, and among clumps of hazel, etc. on lower grounds. 



The author collected fossil shells in the loess of Natchez, 



M_i&s.. , but none have yet been found in the northern 



loess. 



**Sphyradium edentulum alticola (Inger.) Pits. 



While this form scarcely deserves rank as a variety, the 

 name is here retained to designate the common loess fossil 

 which is identical with recent shells (commonly known 

 under the varietal name) which are now found in Wyom- 

 ing, Colorado, etc. This form is much elevated, and has 

 a distorted body-whorl, which destroys the symmetry of 

 the otherwise almost perfectly cylindrical shell. Typical 

 cdcntnlum is exactly like the upper part of the shell of the 

 variety and is a less fully developed form. An occasional 

 shell of the varietal form is found eastward with the type. 

 Speaking of the recent shells Dr. Sterki says:* "There 

 are, among the common form, high specimens with 

 narrower penultimate and wider last whorl, found every- 

 where occasionally in this country as well as in Europe ; 

 and thus P. alticola Inger. t is not even a true var. here." 



However in the Rocky Mountain region the variety is 

 the common form, and it is likewise generally distributed 

 through the northern loess, belonging to the category of 

 the most common and most characteristic loess fossils. 



Only two recent specimens have thus far been taken at 

 Iowa City. As both are rather young shells it is impossible 

 to determine whether they are the type or the variety. As 

 the distinction between them, however, is not worthy of 

 maintainance, they are here grouped together. 



c. Terrestial species of lower, shaded, alluvial 

 grounds, under sticks, leaves, etc. 

 **Polygyra viultilneata (Say) P/ls. (Large form) . 



Two forms of this species occur here. The larger, the 



* Nautilus, vol. vi, pp. 6 and 7, May, 1882. 



f First described as Pupil/a alticola Ing-ersoll, in Bull. U. S. Geol. 

 Sur. of the Terr., 2, p. 128,-1875. 



