THE 
AMERICAN GEOLOGIST. 
Vol. XIV. OCTOBER, 1894. No. 4. 
NANNO, A NEW CEPHALOPODAN TYPE.* 
By J. M Clarke, Albany. N". V. 
(Plate VI.) 
The material representing this remarkable type of cephalo- 
pod structure was collected by Messrs. E. O. Dlrich, Charles 
Schuchert. and the late W. H. Scofield from various localities 
in the Trenton series of Minnesota. The novel character of 
the fossils was recognized and closely studied by tin- first two 
of these gentlemen. 'When, therefore, the specimens were 
placed in my hands for description I was able to avail myself 
of these previous observations, especially those by Mr. Schu- 
chert. 
The usual aspect assumed by these bodies is somewhat that 
of a small Belemnites. The apical and posterior portion has 
a rounded and evenly tapering surface which would give it 
the form of a true cone, were nut one side, when the body is 
viewed laterally, quite oblique, while the other is nearly verti- 
cal. Thus viewed the shells a re asymmetrical laterally, but 
as seen from the dorsal and ventral side they are bisymmet ri- 
cal. After the conical expansion has continued for about, or 
less than, one-half the length of the body, there is a rather ab- 
rupt contraction on the oblique side and the shell becomes 
♦Published with the consent of tie' State Geologist of Minnesota. 
