PLATES 50. 
Fig. 1. 271. 24. OrtHocERAS sSTRIGATUM. (Pag. 205.) 
1 a. A young specimen, with the shell partially exfoliated ; a few of the septa being indistinctly visible. 
1b. A fragment, showing the shell in a considerable degree of preservation. 
1c. A portion of the surface of the last enlarged, showing the flexuous character of;the striz. 
1d. A large specimen, preserving but indistinctly the strie. About twenty of the chambers are preserved, as 
well as a large part of the outer chamber. This specimen shows a small septate tube within the open 
extremity, but it is probably accidentally present. 
le, f. A fragment, showing five chambers, with a section of the same. 
Fig. 2. 17. 2. OrnTHocERAS LAQUEATUM. (Pag. 206.) 
2a. A fragment imbedded in compact limestone. 
26. A small fragment, showing the intermediate finer strie. 
2c. A portion of the surface enlarged. 
Fig. 3. 272. 25. OrTHocERAS LAQUEATUM? var. a. (Pag. 206.) 
Fig. 4. 286. 1. CAMEROCERAS TRENTONENSE. ( Pag. 221.) 
4 a. A fragment of the shell, preserving about three of the chambers, beyond which the siphon is extended to 
an equal distance. 
4b, Another fragment, with the siphuncle still more extended. 
4c. Transverse section, showing the position of the siphuncle. 
