Foerste.] 
290 
[May 1, 
tally, the spire is elevated 6 to 7 mm. above the slit band of the last 
volution, the height of that volution below the slit band being 16.5 
mm. There were three and a half volutions. 
This form is represented in the Clinton by a single specimen from 
Cumberland Gap, Tennessee. The same form occurs in the Niag- 
ara of Wisconsin, Iowa and Ohio, and differs from the species as 
represented by the Lower Helderberg forms in the less vertical 
height of the oral end of the outer volution. The Ohio specimens 
are still more depressed than the other forms, referred to variety 
occidens. 
Cyclonema bilix, Conrad. 
(plate v, fig. 15.) 
At Brown’s Quarry, near New Carlisle, Ohio, specimens are found 
which cannot be distinguished specifically from Cyclonema bilix of 
Lower Silurian strata. It consists of three and a half volutions, in- 
creasing rapidly but regularly in size. The spire is elevated 14.5 
mm. above the oral end of the last volution of a specimen whose 
total height is about 30 mm., and whose greatest diameter trans- 
versely is 35 mm. The volutions are convex, the upper part of the 
volutions however, being obliquely flattened, especially toward the 
aperture. The surface is marked by numerous revolving striae, some 
of these larger and coarse, between which the remainder are inter- 
calated. The latter, although not alwa} r s so readily seen at first 
sight, can be easily found on examination. Fine, close, and evenly 
developed transverse striae cross the revolving striae, curving ob- 
liquely backwards. In addition to these striae, the shell is more or 
less wrinkled in the same oblique direction as the transverse striae. 
While the transverse striae often require a low power lens, the 
wrinkles are readily seen with the unassisted eye. The peristome 
shows no evidence of folding. 
This species occurs not infrequently in the upper courses of the 
Clinton Group, at Soldiers’ Home and Centreville, Ohio. 
Holopea obsoleta, Hall, var. elevata, var. nov. 
(plate VI, FIG. 17.) 
A small gasteropod shell is found in considerable numbers at 
Cumberland, Gap, Tennessee. It is composed of two and a half vo- 
lutions. The first volution is very small, 1.3 mm. in diameter. The 
second volution increases in size moderately, attaining a diameter of 
