TLATE XXXVI. 



Orthoceras PRAVm. 



Pftge 255. 

 See Plates 35, 81, 112. 

 Pig. 1 . A («pt«te fragment, preserving' nearly its normal form. The transverse strite and areolar markings 

 and striations on the septa are not I'epresented. 



Orthoceras stylus. 



Pago 253. 

 See Plate 79. 



Fig'. 2. A small individual, preserving thirteen chambers and a portion of the grand chamber. A longita- 



dinal section of this specimen is shown in fig. 1, pi. 79. 

 Fig. 3. A larger individual, showing the great length and cylindrical form of the chamber of habitation. 



Orthoceras Ohioensi. 



PaKe 2Sfi. 

 See Plate 35 A. 

 Fig. 4. Lateral view of an indi^ndual, retaining the chamber of habitation and twenty adjacent chambers, 

 showing the slight curvature of the tube, which is apparently a noi-mal feature. Upper Hel- 

 derberg, Delauxire, 0. 



Ctrtoceras EUOENIDM.' 

 Page 369. 

 See Plates 47, 96, 97. 

 Pig. 5. The inner side of a portion of the shell imbedded in limestone, showing Httle or no curvature, with 

 the lamells extending on either side. A reraai-kably large individual of the species. This speci- 

 men is the original of Orthaceras foliatum. Schoharie grit, Schoharie, N T. 



