>Hi James,
I believe Norrisia norrisi Sowerby is the only living member of the genus.
On an old listing of fossil species I have, I see a Norrisia microphalus
listed, from the Eocene deposits of the Gosport Formation in Alabama.  I
know nothing about it. Norrisia has a really neat operculum.  It looks like
a coil of rope.
Regards,
Paul M.

I see the ball is in my court now. K. V. W. Palmer and D. C. Brann
(1965-66) compiled a 2-volume work, "Catalogue of the Paleocene and Eocene
Mollusca of the Southern and Eastern United States: (Bulletins of American
Paleontology, v. 48, no. 218, 1057 pp., 5 pl.). Marvel of marvels, this
work is still available from the Paleontological Research Institution, and
they have a Website.  It IS a catalog--there are only a few
illustrations--but it will tell you the complete synonymy of each species
up to 1965 as revised by an expert, where the species may be found in
outcrop, and where the type specimens are housed, plus a bibliography. It's
one of those works that would probably be published on-line today rather
than on paper, yet it is one of the most useful books I have on Alabama
paleontology.

According to Palmer and Brann, there are three species of Norrisia in the
Coastal Plains of the eastern and southern U.S., plus a possible fourth.
All are known only from Claiborne Bluff, in the middle Eocene Gosport Sand
(formerly called the "Claiborne sands"):

Norrisia (Norrisella) micromphala (Cossmann, 1893)
Norrisia nautiloides (Aldrich, 1911)
Norrisia (Norrisella) nitens (I. Lea, 1833)
cf. Norrisia (Norrisella) parva (H. C. Lea, 1841)

To fend off the obvious question, H. C. Lea was the son of Isaac Lea; the
son wrote an article naming several tiny gastropods from the Gosport Sand
at the age of 19 or so, if memory serves.

For a taxonomic discussion of these species, see:

Palmer, K. V. W., 1937, The Claibornian Scaphopoda, Gastropoda, and
dibranchiate Cephalopoda of the southern United States: Bulletins of Ame
rican Paleontology, v. 7, no. 32, pt. 1, 548 p.; pt. 2, 90 pl. Long since
out of print, but should be available at the library of James' huge local
university.

Andrew K. Rindsberg
Geological Survey of Alabama