PLATE XCIIL 
Gomphoceras rude. 
Page 327. 
Fig. 1. Ventral view of the specimen, showing the crenulated band, the depth of the air-chambers, and the 
siphuncle, as exposed from the process of weathering. The specimen preserves more of the 
chamber of habitation than is represented in the figure. The curvature and sinus in the mar¬ 
gin, as represented in the figure, do not belong to the aperture. Schoharie grit. Scho¬ 
harie, N. Y. 
Gomphocekas clavatum. 
Page 323. 
See Plate 46. 
Fig. 2. Ventral view of an individual, showing the characters of the chamber of habitation, near the aper¬ 
ture. Schoharie grit. 
Fig. 3. A large, compressed individual, referred with doubt to this species, but preserving several of the 
specific characters. Schoharie grit. Schoharie, N. Y. 
Gomphoceras cruciferum. 
Page 328. 
Fig. 4. A septum, showing the transverse section of the tube and the peculiar cruciform ornamentation 
around the siphuncle, surrounded by indistinct striae. The upper, narrower end of the sep¬ 
tum is probably the concave side of the tube. Schoharie grit. Schoharie, N. Y. 
Gomphoceras tumidum. 
Page 351. 
See Plate 95. 
Fig. 5. A fragment of the chamber of habitation, near the aperture, showing the slight sinus in the margin, 
corresponding to the small aperture. 
Fig. 6. A fragment of an individual, showing the ventricose chamber of habitation and the depth of the 
air-chambers. Chemung group. Ithaca, N. Y. 
Gomphoceras poculum. 
Page 340. 
Fig. 7. A portion of an individual, somewhat compressed, showing the variation in the depth of the air- 
chambers, and the furrows of the crenulations continued over the walls of the chambers. The 
furrows do not extend over the grand chamber toward the aperture, as represented in the 
figure, the internal mould of this portion being essentially smooth. 
Fig. 8. The opposite side of the apical portion of the preceding, showing the elements of the siphuncle, as 
exposed from weathering. Hamilton group, near Cazenovia, N. Y. 
Gomphoceras solidum. 
Page 338. 
Fig. 9. A large portion of an individual, showing the form of the shell and the depth of the air-chambers. 
The change of the slope of the sides from the point of greatest gibbosity is more abrupt than is 
represented. The specimen also shows the crenulated zone, and the crenulations extending 
over the cast of the walls of the air-chambers. Goniatite limestone. Manlius, N. Y. 
