1853.] Report on the Geological Structure of the Salt Range. 277 



The number of belemnites in the shales in some places is quite 

 wonderful, and two species at least occur. The alveoli of the belem- 

 nites are frequently found attached to the osselit, and in their inte- 

 rior the casts of the chambers of the alveolus or phragmacone. These 

 are often found detached, and when seen in the rock, have much the 

 appearance of an orthoceratite, being composed of concave or convex 

 discs, fitting one into the other, and having thin articulating surfaces 

 highly polished. Indeed were it not for the want of a siphuncle 

 and the ease with which a disc can be separated from its neighbour, 

 the similarity to an orthoceratite would be complete. Each disc 

 seems entirely disconnected from its fellow ; but no partition of the 

 original chambers could be detected between them, the convex sur- 

 face of the upper disc being capable apparently of free movement on 

 the concave surface of the lower one, as in a ball and socket joint. 

 These discs are sometimes of large size, one specimen which we pro- 

 cured being two inches in diameter. 



Ammonites, though occurring in the shales, are most abundant in 

 the green sandstone. They are generally ill preserved and are liable 

 to fall to pieces in extracting them, having been acted on by the 

 sulphurous acid, which is generated in the sandstone by the decom- 

 position of pyrites. Two or three species have been procured. 



Of the genus Gryphea, we have obtained probably two species, one 

 of which closely resembles the Gr. incurva. They are generally ill 

 preserved. 



A large bi-valve, probably a species of Plagiostoma, is very abun- 

 dant in the green sandstone, but good specimens are with difficulty 

 procurable. 



In some places bones and teeth of saurians occur in the sandstones, 

 but are no where plentiful. The bones are generally fragmentary, 

 very brittle and crumbly. Nothing like a complete skeleton was 

 observed, the most perfect relic obtained being a portion of a scapula 

 attached to a bit of a humerus. The teeth are better preserved than 

 the bones, but are also very brittle. They are covered with a dark 

 brown enamel, are compressed, sharp pointed and beautifully striated 

 on their surface. One, which we found, but which fell into frag- 

 ments in attempting to extract it, was at least three inches long and 

 about an inch broad at the base. The decomposition which the 



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