This is a very small snail. It is apparently very widespread in the
eastern United States, and shows up in Iowa in most of the counties that
have records.
This species is found in a wide variety of habitats. I usually
find it under wood or wet bricks on a concrete pad that we have in our
back yard.
This species always seems to have small particles of dirt stuck to its
shell.
It can be difficult to photograph this species and it can also be
difficult to track them. Often there are two or more similar looking
species under the same log or brick.
While the Vertigo group is varied and often
separated by pretty subtle differences, this species is pretty
distinctive, not only for the thickened single lamella, but for its
small size and the distinctive shape of its shell.