1889 .] 
265 
[Foerste. 
feet, the rocks all belong to the Cincinnati group, of the Lower 
Silurian. The Cincinnati beds are fossiliferous at the veiy top.” 
It would be of interest to determine the existence of the Medina 
in Indiana more definite^, since no very satisfactory paleontolog- 
ical evidence has ever been furnished of its occurrence on the Cin- 
cinnati anticlinal axis. 
A few specimens were also loaned from the cabinets of Mr. B. 
B. Thresher and Mr. Ira Crawford of Dayton, Ohio, and a number 
of specimens were examined in the collection of Dr. S. B. Welch 
of Wilmington, Ohio. The types of Professor Hall, from the Clin- 
ton group now in the collection of the Central Park Museum of 
New York City, were kindly placed at my disposal for examination 
by Prof. R. P. Whitfield. Professor Newberry also permitted me 
to examine the Ohio Clinton specimens now in the cabinet of Col- 
umbia College. Finally, my own collections from the Clinton of 
Ohio, and the result of many years collecting have been freely used 
for comparison. 
In the description of the fossils an attempt has been made to 
show the amount of variation of the more variable species. It may 
seem to some that too great a degree of variability has been allowed 
and that forms here considered varieties ought to have been re- 
tained as species. Those who have examined large collections 
from many localities will recognize that in such cases many inter- 
mediate varieties must be left undescribed or can not be referred to 
any particular species. In each case we have designated to the best 
of our ability the particular variety described, and advocates of 
either method will have no trouble in recognizing their forms no 
matter what their association. 
Paleontology. 
Calymene Blumenbachii, var. Vogdesi, Foerste. 
This form was first described from the Clinton rocks of Centre- 
ville and Soldiers’ Home, Ohio. It is to be distinguished from 
Calymene Blumenbachii chiefly by the broad anterior border of 
the head. This has usually a general flattened appearance, being 
elevated at a moderate angle. This single character is perhaps 
scarcely sufficient to distinguish a species. Calymene Niagarensis , 
Hall, presents a similar flattened, broad, anterior border in some 
New York Niagara group specimens at hand which is perhaps of 
equal morphological value, considering the generally much smaller 
size of this form. 
