281 
[Foerste. 
edging to each chamber, at a definite distance from the outer surface. 
At another place where the shell is worn, this concave edging to 
the chambers is noticed to consist of a large number of concave 
depressions around a part at least of the edge of each chamber. 
This structure was not observed in the section already referred to, 
but on a worn surface of the shell. It is impossible to determine 
whether this represents genuine structure of the shell, or an acci- 
dent of fossilization ; perhaps the latter view is the safer for the 
present. Possibly it belongs to the larger subgenus, Geisonoceras. 
This species can readily be distinguished from 0. Grawfordi , by 
the oblique groove of the cast, and the greater number of septa ; 
the septa being 1.7 mm. apart in 0. Hanoverensis , where the shell 
has a diameter of 12 mm., while at the corresponding diameter of 
0. Grawfordi , the septa are 2.5 mm. distant. 
Orthoceras (cycloceras) nova-carlislensis, sp. nov. 
(plate V, FIG. 25 ; PLATE VIII, FIG. 1.) 
The type specimen was found at Brown’s Quarry, two miles west 
of New Carlisle, Ohio. It is 68.5 mm. long and contains in a length 
of 54.6 mm., nine chambers or ten septa. The remainder of the 
shell, above the chambered portion may have been once septate, 
or it may have been the base of the living chamber. The smaller 
end of this specimen has a diameter of about 28 mm., and the 
larger end, 33 mm. These measurements are not altogether accu- 
rate, on account of a slight crushing of the specimen. Another 
specimen, probably the living chamber, has a length of 102 mm., 
well preserved. It has a diameter of 36.5 mm. at the smaller end 
and 46 mm. at the larger end. The exterior of the shell is stri- 
ated transversely, the striae being very regular in size and in the 
frequency of their occurrence, about forty striae occurring in a 
length of 20 mm. or four in a length of 2 mm. 
In examining the character of the surface ornamentation, it is 
always necessary to be certain that the surface is really being ex- 
amined and not the exterior of some inner layer of the shell. Thus 
in the longitudinally striated 0. Grawfordi the inner layer is smooth, 
and in the transversely striated 0. Nova-Garlislensis , the inner layer 
is very finely striated, twelve to thirteen striae occupying a length 
of 2 mm. The septa are of medium concavity, forming an arc of 
about 123° in the t} 7 pe specimen, and at the base of the specimen 
