232 Geological Society. 



2. The second case, in which animal matter has been partially 

 changed, was illustrated by the following experiments. Portions of 

 a stag's jaw from the Brighton chalk rubble, of a fish-bone, and a 

 shark's tooth from the London clay, when dissolved in diluted mu- 

 riatic acid, gave only a brown powder ; and the animal matter of a 

 fragment of the humerus of a mastodon from Big-bone-lick exhibited 

 but little flexibility, and was easily torn, particularly in the longitu- 

 dinal direction. It was found impossible to make sections of the 

 jaw-bone of the stag or the humerus of the mastodon for microscopic 

 observation. Part of a human parietal bone found upon the site of 

 the cathedral of Old Sarum, and human bones obtained from the 

 church-yard of St. Christopher le Stocks, on part of which the Bank 

 of England stands, were ascertained to have had their animal matter 

 reduced to the same state as that of the stag's jaw. A fossil oyster 

 from the Isle of Wight, when placed under the microscope, showed 

 black spots over its surface, and the structure of the shell was appa- 

 rently destroyed. A fragment of a Pecten from the lias also exhi- 

 bited opaque spots. Part of an ammonite when dissolved left a sub- 

 stance resembling Sepia. 



3. The third case, where only the carbon of the animal matter 

 remains, was explained by two series of experiments, one of which 

 proved it to be associated with bitumen, and the other that it existed 

 by itself. The scales of Dapedium politum and other fishes from 

 Lyme Regis, when acted upon by acid, left carbon undissolved ; and 

 when heated under a test-tube gave a considerable quantity of 

 bitumen*. 



Portions of the bones of the Ichthyosaurus and Plesiosaurus from 

 the lias, yielded a black residuum, which deflagrated with red hot 

 nitre, and the resulting mass gave a precipitate with chloride of cal- 

 cium. To prove that the carbon was a portion of the bone and not 

 an adventitious ingredient, a section was made, and the greatest 

 quantity of carbon was found in the thickest part ; and an analysis 

 showed that the proportion of carbon was about the same as in the 

 animal matter of a similar mass of recent bone. A still further proof 

 was adduced, in no gelatine having been detected after 36 hours 

 boiling of a fragment of the fossil. A section of recent bone dis- 

 played, when carbonized by heat and charged with crystals of alum 

 or a composition of whitening, a similar appearance in the arrange- 

 ment of the carbon as in the fossil bone. No bitumen was given off", 

 when fragments of these bones were acted upon by heat under a 

 test-tube.* 



With respect to the second great class in which the animal matter 

 has been removed, the following cases were mentioned : — Portion of 



* [We presume it is here intended to be implied, though it is not so 

 stated, that the bitumen associated with the carbon in these fossil fish- 

 scales is itself a part of the altered animal matter, in a state of imperfect 

 carbonization. Such an inference would appear to be confirmed by the 

 negative result obtained with the bones of the Ichthyosaurus and Plesio- 

 saurus subsequently stated. See the observations of Mr. Murchison and 

 Mr. Faraday on the origin of the bitumen in the bituminous schist cf See- 

 feld, in Phil. Mag. and Annals, N.S., vol. yi. p. 39. — Edit.] 



