Spirifer raricosta, A medium sized spirifer common 
in the Onondaga Limestone. It has been described under 
the names Spzrifer undulatum, S. raricosta, Delthyris un- 
aulatuim. 
CRUSTACEA. 
Phacops bufo. A small trilobite occasionally found. 
Odontocephalus selenurus, Another which is charac- 
teristic of this period, and is quite abundant. Asits name 
implies, it is the spiked-head, moon-shaped tail, trilobite. 
Although parts of this specimen are very common, es- 
pecially the pigidium, whole specimens are rare. Owing 
to this fact, it was long thought that the head and tail 
portions were parts of two different trilobites, and they 
were accordingly given different names. Forsome time the 
head was known as the Calymene odontocephalus, and the 
tail as the Asaphus selenurus, but later an entire specimen 
was found, and it was accordingly known as the Odontio- 
cephalus selenurus. 
The Dalmanites (Coronura) Myrmecophorus is a large 
and exceedingly beautiful trilobite existing somewhere in 
this period. The exact layer is as yet unknown. No 
whole specimen has yet been found, but the few frag- 
ments all show that it is large and handsome. An entire 
specimen of the same proportions as the largest fragment 
would indicate a trilobite over a foot in length. 
VERTEBRATA. 
Fish spines are the only parts which have as yet been 
found in our county. In some of the counties east of us, 
however, the fossil form of the entire fish has been found. 
HAMILTON PERIOD. 
The next period which we find in our trip toward the 
south is the Hamilton. This period consists of sand- 
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