riATE XL\ 1. 



GoMPnOCERAS CONRADI. 



rage S48. 

 Tig. 1. Lateral view of a small iiulividual, showing the eiKiogastiio curvature of the tube, the furrows of 



the crenul&tioiis at the base of the chamber of habitation, and the coucentnc striiB of the teat 



over the septate portion. Uoniatite limestone. Manlius, N^. T. 

 Vig. 2. Ventral view of the pi-eceilinjf, showings the small apertuie inJ the form of the shell. 

 Fig. 3. Veutral view of the chamber of habitation of a lai-ger individual, showing' the constriction of t'.e 



lube near the ajwirlure, and the narrow, crenulated zone at the base. Goniatite limestone. 



Manlius, y. Y. 



GOMPHOCEHAS BETA, 

 rage im. 

 Fig. 4. An individual considerably compressed, preserving the greater portion of the chamber of habitation 

 and air-cbanibei-8. The curvatui-e of the sutures is due to compression. Schoharie grit. 

 Schoharie, 2f. Y. 

 Fig. 5. Ventral view of the chambered portion of anotlier individual, showing the impression left by the 

 removal of the siph uncle in the pi-ocess of weathering. Schoharie grit. iScholtarie, iV. Y. 



GOMPHOCERAS OVIFORME. 



Page 314. 

 See Plates 45, 94. 

 Fig. 6. A small, globose individual, showing the general form of specimens of this size. The epidermal 

 layer of the test has been exfoliated at the apical portion of the tube, showing the markings 

 and strnctui-e of the nacreous layer. Goniatite limestone. Scholiarie, N. Y. 

 Fig. 7. An enlargement of the surface of the apical portion of the preceding, showing the cbaractei-s of the 

 uaci-eous layer of the test. 



GoMPHOCERAS ABSENS. 



Page 344. 



Fig. 8. Lateral view of a fragment showing the curvature of the tube. Schohai-ie grit. Schoharie, N. Y. 



Fig. 9 Venti-al view of the preceding, showing the enlargement of the tube, the regularity of the air-cham- 



bei-8, and the impression of the siphuncle, which has been removed in the process of weathering. 



PhBAGMOCERAS ? EXPAN6UM. 



Figs. 10,_10. This specimen is erroneously figured on this plate as from the Hamilton, but belonging to the 

 Coralline limestone of the Niagara group. See Addenda for explanation. 



The i-epresentation of the sijjhuncle is incori'ect ; the specimen shows^t to be on the concave 

 side of the tube. . 



Ctrtoceras alternatum. 



Page 3B5. 

 Fig. 12. Ventral view, showing the undulations of the tube and the siphuncle, as exposed in the process of 



weathering. The undulations and rounded nodes on the tube are not fully repi-eseiited in the 



figui-e. Goniatite limestone. Schoharie, N. Y. 

 Fig. i;). Lateral view of the preceding, showing the curvature of the tube. 



GOMPUOCERAS CLAVATUM. 



Page 3-23. 



See Plate 93. 



Fig. 14. Lateral view, showing the endogastric curvature of the tube and the comparative convexity of the 



dorsal and ventral sides. Schoharie grit. Albany county, N. Y. 

 Fig. 15. A view of the convexo-doi-sal side of the preceding, showing the form of the tube and the depth of 

 the air-chambei-8. 



