350 The American Geologist. December, iiioi 
**Pyramidula perspectiva iSay) Pils. 
Common on shaded banks, etc. under decaying logs. This 
species is not generally distributed in the loess, though it is 
very common at Natchez, Miss. At Iowa City it occurs rather 
abundantly in but one exposure. 
*'''Helicodiscus lineatus {Say) Morse. 
Scattered specimens are not infrequent. They are usually 
found in deeper shade under sticks and logs. Fossil shells 
are quite rare. 
*PuNCTUM pygmaeum (Drap.) Binn. 
This minute shell is easily overlooked, but is quite com- 
mon under sticks and fallen bark on northerly shaded slopes, 
and among clumps of hazel, etc. on lower grounds. The au- 
thor collected fossil shells in the loess of Natchez, Miss., but 
none have yet been found in the northern loess. 
**Sphyradium edentulum alticola (Inger.) Pils. 
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 Wyoming, Col- 
orado, etc. This form is much elevated, and has a distorted 
body-whorl, which destroys the symmetry of the otherwise 
almost perfectly cylindrical shell. Typical edentulum is ex- 
actly 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 everywhere occasionally in this country as well as in 
Europe ; and thus P. alticola Inger. f 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 com- 
mon 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 
*Nautilus. vol. vi, pp. 6 and 7, May, 1882. 
fFirst described as Pupilla alticola Ingersoll, in Bull. U. S. Geol. Sur. oi the 
Ter , 2, p. 128, 1875. 
