'27H Tin American Geologist. November, 1893 
The ornamentation is most like that of Aspidichthys (Pal. of Ohio 
and Monograph) and your specimen and those I have from Schoharie 
may represent a species of that genus of which we know very little. 
"The specimen was found in the Marcellus shale at the foot of Slate 
Rock fall, near Geneva, Ontario Co., N. Y., 2o feet below the basal 
limestone of the Hamilton group, in October, 1890." Dr. Lincoln. 
Another specimen recently found by Dr. ( Hark of Berea is of 
so aberrant a form from that of the other dinichthyids that 
I was at first inclined to doubt its generic alliance. Hut as 
it is of the same type, and only differs in such modifications 
as allow the recognition of every part. I have deemed it wiser 
to put it into the same genus reserving the possibility of fu- 
ture change when other parts of the fish shall become known. 
Fortunately the specimen was extracted from the matrix 
in an absolutely perfect condition, so that no difficulty is met 
with in recognizing every part. It is remarkable in the first 
place for its uncommon size, measuring fourteen inches in 
length, and secondly for its attenuated form, which is in strik- 
ing contrast with the ordinary massive premaxillary of 
Dinichthys. The terminal cusp is four inches long and about 
one inch across at its middle, smooth and tapering. The 
flange alluded to in the description of J), lincolni. widens 
the tooth to two inches. No tubercles or other ornaments 
mark its surface, which is perfectly smooth and polished. 
The lower (upper or inserted) part of the tooth spreads out 
into a flat base, roughened as usual for insertion into the 
bone or cartillage of the skull, differing in this part very lit- 
tle from the ordinary structure of the teeth of the genus. 
A side view, as given in plate xn, shows that the tooth 
does not form at its middle a right angle but curves regularly 
from base to tip, the extreme ends being at an angle of 
about 120° with each other. 
It is not ahvays wise to infer the size of an animal from a 
single organ, but it is not possible to avoid the impression 
that we have here an unmistakable indication of a fish, 
whether truly a Dinichthys or not. which must have rivalled 
all but the very largest known species of its genus. It may 
have been more slender and consequently like its tooth, less 
massive, but a head capable of carrying and using so formid- 
able a weapon must have belonged to a fish porportionately 
large and powerful. 
