PLATE 56. 
Fig. 1. 271. 24. Orthoceras strigatum. (Pag- 205.) 
1 a. A young specimen, with the shell partially exfoliated ; a few of the septa being indistinctly visible. 
1 b. A fragment, showing the shell in a considerable degree of preservation. 
1 c. A portion of the surface of the last enlarged, showing the flexuous character of^the striae. 
1 d. A large specimen, preserving but indistinctly the striae. 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. 
1 e,f. A fragment, showing five chambers, with a section of the same. 
Fig. 2. 17. 2. Orthoceras laqueatum. (Pag. 206.) 
2 a. A fragment imbedded in compact limestone. 
2 b. A small fragment, showing the intermediate finer striae. 
2 c. 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. 
4 b. Another fragment, with the siphuncle still more extended. 
4 c. Transverse section, showing the position of the siphuncle. 
