CEPHALOPODA. 
353 
The specimen figured has a length of forty-seven mm. and embraces eight 
air-chambers. 
This species is distinguished by its transverse section, apical angle, and the 
smooth internal mould. It is described from a fragment of the chambered 
portion, and is referred to this genus on account of the large apical angle, and 
the elliptical transverse section. 
Formation and locality. In the shales of the Hamilton group, on the shore of 
Seneca lake, N. Y. 
In the genus Gomphoceras, as in Orthoceras, the actual number of species 
described from the Chemung group bears a small proportion to the number of 
forms indicated by numerous fragments, which are too incomplete and imperfect 
to admit of specific distinction. The upper members of this group are charac¬ 
terized by a very distinct fauna, compared with that of the lower beds, and are 
intimately connected with the succeeding formations. In the Waverly group 
several forms have been observed belonging to this genus, together with Ortho¬ 
ceras ; but the present collections from this group are too meager to furnish 
satisfactory results. The collections from the Upper Chemung are also, com¬ 
paratively, very limited. A complete knowledge of the Cephalopodous life of 
the Upper Devonian system, and of the beds of transition to the higher forma¬ 
tions, can only be obtained by the study of larger collections than have yet 
been made; and any generalizations at this time would be premature. 
45 
