PLATE XXXIX. 



Orthoceras Bebrtx, var. Caydoa. 



Pago 276. 

 See PlattjB 86, 91, 92. 

 Fijf. 1. An internal cast, showing a portion of the chamber of habitation and fifteen of the adjacent air- 

 chambers. Lower beds of the Chemung. Curtland, Cortland county, N. Y. 



Orthocekas Bebryx. 



Page 275. 

 See Plates 38, 83, 84. 

 Fi(f. 2. A fragment, obliquely compi-essed, producing an arching of the septal sutures. Hamilton group. 

 Madison county, N. Y. 



Orthoceras exile. 



Page 290. 

 See Plates 84, 85. 

 Fig. 3. An indMdtial nearly entire, showing the gentle constriction of the tube near the aperture, and the 

 slender form of the shell. This is the original specimen of the species, and is from the coarse 

 shales of the Hamilton g^-oup at Cazenovia, Madison county, N. Y. 



Orthoceras emaceratum. 



Page 292. 

 ' .See Plate 85. 

 Kg. 4. The original of the species, showing the depth of the chambei-s and the gradual enlargement of the 

 tube. Hamilton group, South S?ioTe of Lake Erie. 



