904 THE PALEONTOLOGY OF MINNESOTA. 
(Conradella. 
Collectors have heretofore identified this species with Hall’s Bucania expansa 
from the Trenton of New York,* but a comparison proves it quite distinct. In the 
first place, though of about the same size, there is one volution less. Next, the last 
volution is relatively narrower and higher just behind the aperture, and the latter 
very differently outlined. Finally, the last volution is nowhere triangular as is 
the case in the Trenton species. Compared with S. buelli and S. sculptilis the 
outer volution will be found much larger especially as regards the dorso-ventral 
diameter. 
In practice the most difficult perhaps to separate from this species is the 
associated Bucania simulatrix. Though of widely different affinities, casts of these 
two species, especially when, as is usually the case, the aperture is imperfect, are 
very apt to be confused. Still, after familiarizing one’s self with certain differ- 
ences, they may be distinguished almost ata glance. In the first place the volutions 
of the Bucania are more slender. This difference is particularly striking in an 
apertural view, the small end of the outer volution, in specimens of the same hight, 
being at least a fourth wider in the Salpingostoma. Inthe Bucania again the width 
of the last volution continues to increase quite uniformly instead of being almost 
constricted near the aperture. When the latter is preserved the difficulties have 
vanished, for this part is readily distinguishable. 
Formation and locality.—Richmond group of the Cincinnati period, at Richmond, Indiana, where 
casts of it occur rather abundantly. Good specimens, however, are anything buf common. 
Collection.—K. O. Ulrich. 
Genus CONRADELLA, n. gen. 
Phragmolites, CONRAD, 1838, Ann. Geol. Rep. New York, p. 119. 
Cyrtolites (part.), HALL, 1847 and 1871. MEEK and WoRTHEN, 1868. MEEK, 1873. S. A. MILLER, 
1874 and 1892, 
For generic characters and list of species see pages 851, 852. 
It is strange that this sharply defined genus of shells has been so uniformly 
confused with Cyrtolites. Aside from the fact that the whorls are similarly coiled 
in the two groups, there is not a single character in which they are identical. While 
the typical forms of Cyrtolites have no slit-band and in some cases not even a sinus 
in the outer lip, Conradella has not only a sharply defined raised band, but an 
unusually long apertural slit as well. The form of the volutions also is different, 
the transverse section in the former being more or less rhomboidal, while in the 
latter it is ovate or obcordate. Finally, the surface markings are not at all similar, 
*The erroneous identification of this and a number of other Trenton fossils in the upper member of the Cinvinnati 
period, is responsible for the commonly prevailing yet groundless idea that the faun. of the “‘ Cincinnati group” is a sort of 
mixture of ‘*Trenton and Hudson River types.” The sooner paleontologists will come to realize that a careful comparison 
of the fossils themselves is one of the first necessities in a successful identification or discrimination, the better it will be 
for stratigraphical geology. Mistakes are always possible, but time and care will avert most of them. 
