FOSSILS FROM THE SILURIAN FORMATIONS OF 
TENNESSEE, INDIANA AND ILLINOIS 
Aug. F. Foerste 
The Silurian formations of Ohio, Indiana, and Tennessee con- 
tain a large fauna which awaits elaboration. Preliminary notes 
on some of the Tennesseean fossils were published in a paper on 
Silurian and Devonian Limestones of Western Tennessee, in the 
Journal of Geology, m 1903, with the expectation of their further 
elaboration and illustration. Plates were prepared during the fol- 
lowing year, but not published, in the hopes of securing further 
material in the field. Other duties have intervened, and for some 
time to come will prevent further study. Under the circumstances 
it is considered best to publish these plates with their accompany- 
ing notes in their present condition, awaiting a future opportunity 
for more complete study. A part of the figures refer to fossils 
from Indiana, and a few of the notes include references to forms 
from Illinois. Several terms of a subgeneric character have been 
proposed. Whether these terms will commend themselves or not 
will depend largely upon the question whether future studies will 
show that they include groups which indicate close affinity and 
are sufficiently distinct from the types of the genera already 
described to warrant the separation of these groups from former 
genera either as subgenera or as independent genera. All the 
available material has been utilized in an attempt to define these 
groups. In most cases, the material at hand has not been of such a 
character as to submit to treatment by chemicals. 
Cyrtoceras cinctutus, sp. nov. 
{Plate III, Figs, 37 A, B.) 
Gyroceracone; in the specimen figured the living chamber 
occupies a length of 30 mm. However, since the margin of the 
aperture is not distinctly preserved, its original length may have been 
greater. In a poorly preserved gyroceraconic shell from the same 
part of the section, with only indistinct traces of costae, the broken 
