330 Cincinnati Society of Natural History. 
than three times the cubic capacity of the smaller, has all the teeth 
more developed, more bent inward, and the inner upper tooth distinctly 
reflected toward the base of the shell. It is a very distinct and well 
marked variety, to say the least of it. 
36. 7. tridentata, Say.—A small, heavily-ribbed, dark-colored va- 
riety, occurs sparingly. 
37. Triodopsis fallax, Say.—A few specimens of the typical form 
were found. 
38. Succinea obliqua, Say.—A single dead specimen of this species 
was found by Miss Mary Wilder, in the heather, at the very summit 
of Roan High Knob. This aspiring mollusk is the only Succinea thus far 
recorded from this region, so far as I have been able to learn. 
The above comprises a complete list of all the species that I have 
seen from Roan Mountain, though I am satisfied that it is far from 
being complete. There is a number of small shells, belonging to the 
Hyalind division of Zonites that have not yet been studied. Doubt- 
less varieties of several common species remain to be discovered, and 
the finding of half a dozen new species by random search during the 
hot, dry months of summer, by casual visitors, is some evidence that 
protracted residence and systematic searching would bring to light 
many new things. From Roan Mountain, and the eastern and older 
portion of the metamorphic belt, I transferred my theatre of operations 
to the western region, in the Ocoee Conglomerate, and Slates of Safford, 
and much farther to the south, in Monroe county, Tenn. Here the whole 
country is made up of a mass of slates, sandstones, conglomerates, and 
quartzites, dipping to the southeast at a high angle, and forming many 
bold and precipitous cliffs where cut through by the Ocoee, Hiwassee, 
and Tellico rivers in their escape from the mountains to the plains 
further to the west. In 1877, I took a party of students through the 
Ocoee gorge to Ducktown, and on the way found typical specimens of 
M. major and of Z. rugeli, referring the latter to the globular ¢nornatus 
figured by Mr. Binney. Associated with these specimens was a new 
species of Helicodiscus, of which but very few specimens were obtained, 
and these were afterward lost or mislaid, so that it was never described. 
The station was in the debris at the foot of the slate bluffs of the 
Ocoee, I rediscovered the same species this season, in precisely the 
same station, in the gorge of Tellico, and was so fortunate as to secure 
several living specimens, and I now describe it under the name given 
below. 
