I'LATK XCIV. 



OOHPHOCERAS ABRUPTUH. 

 Pago SS9. 

 Fiif. 1. A fifiyment which hiis l)een exti-emely compressoil, showing' a portion of the chamber of habitation, 

 with the septate i«nrt of tlie sh»'U. A consliiction of the IuIm; near the iiiiiUlle of the outer 

 ohnintH-r is not represeiiteii in the tigure. Tlie siiecimen is covered witli a l)rancliing, tiibiilai' 

 Uryozoan. Hamilton group. CaienoeUt, iV. Y. 



GOMPEIOOERAS RAPUANUS. 

 Page 847. 



Fijy. 2 A fr.iginent pi-eserving several air-chambers ami a small poi'tion of tlie g'ranil chamber, showinj^ the 

 IMisition of the plane of greatest transverse section. Hamilton group. I'ratt's FalLi, Uiton- 

 daga county, N. Y. 



Fig. 3. Septum of tlie pi-eceiling, showing the ti-ansvei-se section of the tube. The siphuncle near the ven- 

 tral margin of the septum, and surrounded by an areola, is not i-epresented. 



Fig. 4. An inilividual somewhat compressed, but showing the attenuation of the ai)ex and the depth of the 

 air chambere. The septate portion continues to the point of greatest transveree section at the 

 base of the chamWr of habitation, but is not shown in the figure, owing to being covered by 

 the remains of the macerated shell. Hamilton group. Pratt's Falls, Onondaga county, iV. Y. 



Fig. 5. Ventral side of a 8[iecimen referred to this species on account of the position of the plane of greatest 

 trniisvei-se section and the depth of the air-chambei-s. The specimen is much compressed, but 

 shows the elements of the siphuncle, a.s exposed fi-om weathering, ami the .sinus in the margin 

 of the apei'ture, cori-esponding to the small aperture. The margin of the aperture is entire, 

 anil not broken, as i-epresente<i. Hamilton gi-oup. Cazenovia, N. Y. 



Fig. 10. A fragment preserving the same form and pi-oportions shown in specimen fig. 2. The siphuncle, aa 

 shown at the ventral margin of the septa, is not represente<L Hamilton group. Pratt's I'Talls, 

 Oitondaga county, N. Y. 



GOMPHOCERAS OVIFORME. 

 Fago 314. 

 See Plates 45, 46. 

 Fig. 6. Ventral view of the chamber of habit.ation, showing the small aperture, the constriction of the tube, 

 and the fossa of the crenulated zone at the base. The furrows of the crenulations, extending 

 over the zone and the greater portion of the gi-aad chamber, are not represented. Goniatite 

 limestone. iSc/io?iarie, N. Y. 

 Fig. 7. The last septum of another specimen, showing the size and position of the siphuncle, and the trans- 

 vei-se section of the tube. Goniatite limestone. Schoharie, JSf. Y. 



GOMPHOCERAS AjAX. 



Page 350. 

 Fig'. 8. A portion of the chamber of habitation and three air-chambers, showing the size of the tube and the 

 features of this portion. The striie and furi-ows of the crenidalions, lus continued over the walls 

 of the air-chambei's in the specimen, are not shown in the figui-e. Portage group. PeuJi 

 Yan, N. Y. 



GOMPHOCERAS PINOUE. 



Page Mii. 

 See Plate 95. 

 Fig. 9. A fragment showing the ventrico.se form of the shell and the curvature of the sides of the chamber 

 of habitation toward the aperture. Hamilton group. Cazaujoia, N. Y. 



