PLATE 70. 
Page 
Fig. 1. Orthoceras longicameratum. 343 
1 The siphuncle lias been filled with crystalline matter, and the swollen portions are concave 
above and beneath, indicating a thickening of the septum at its junction with the nar¬ 
rower parts of the siphuncle. Some remains of the septa are still perceptible. 
Fig. 2. 
Orthoceras - (sp. undetermined ). 
Fig. 3 a - d. Orthoceras rigiduji. 344 
3 a. A fragment of this species, having the shell almost entirely removed. 
3 b. A continuation of the same specimen. 
3 c. Transverse section, as shown in the line of fracture of fig. 3 b. 
3 d . Enlargement of the strife. The position of the figure represents the strife in the reverse 
of their natural relation, which is horizontal. 
