Loess of Iowa City — Shiinck. 349 
*StROBILOPS VIRGO (PUs.). 
Locally common on rocky, shaded slopes. It is occasion- 
ally found fossil in the western loess. This has ordinarily 
been reported as Strobila labyrinthica Say. 
Vertigo milium (Gld.) Bimi. 
Not common, on moss}- banks and slopes. Not found fos- 
sil. Its minute size might easily Cause it to be overlooked. 
** Vertigo ovata Say. 
Rare, on mossy, shaded banks, sometimes on lower grounds. 
Somewhat more common as a fossil, occurring sparingly in 
several of the exposures. 
-^Vertigo bollesiana (Morse.) 
Rare, on mossy banks, usually in shady places. It is rare 
in the western loess. 
* Vertigo tridentata IVolf. 
Locally common, usually on rather exposed rocky, moss- 
covered banks. Found sparingly in the western loess. 
**C0CHI,IC0PA LUBRICA (MiUl.) . 
Rare on rather open slopes, etc. It is more common as 
a fossil, but is one of the rarer species of the local loess. 
*CiRCiNARiA coNCAVA (Say) Pils. 
\\^idely distributed on shaded, especially rocky, slopes, but 
not gregarious. It is not found in the local loess, but is quite 
common southward. It is one of the commoai fossils at 
Natchez, Miss. 
**CoNULUS Fui.vus (Dvap.) M'nlL 
Not uncommon on shaded slopes in moss, and under sticks, 
leaves, etc. Fossil shells are not rare, and as a rule are better 
developed than the modern specimens. 
*ZoNiToiDES ARBOREUS (Say) Sferki. 
Very common, usually under logs in high or low places, 
and not uncommonly in comparatively open woods. It can 
not yet be reported from the local loess, but has been found 
by Prof. Savage in the loess of Henry coauity, Iowa, and it is 
not rare in the western loess. 
**Pyramidula alternata (Say) Pils. 
Locally common, usually on higher, deeply-shaded slopes 
imder logs, stones, leaves, etc. Not common in the loess at 
Iowa City. 
