116 MICROSCOPICAL OBJECTS FOUND 



from that by which it is invested. The wide inter, 

 val between the walls of each cell and the shrunken 

 animal, which interval is occupied by transparent 

 flint, like that outside the whole, seems to remove 

 all possibility of doubt. The Levant specimen 

 shews that the animal part of a Rotalia may be 

 occasionally deprived of its calcareous covering, 

 and yet be preserved, illustrating those instances 

 which sometimes occur where this portion alone 

 is found in a fossil state. If any number of living 

 Foraminifera happened to have accumulated at a 

 point where a volcanic spring charged with any 

 solvent acid subsequently burst out, such results 

 would be readily produced. 



Some of the conclusions at which Ehrenberg 

 arrived, resulting from his investigations into the 

 composition of Chalk and Chalk marl, require to 

 be received with great caution, as the facts upon 

 which they are based are scarcely sufficient to 

 support them. One of these is, that " many of 

 the chalk-like formations bordering on the Medi- 

 terranean, in Sicily, Barbary, and Greece, really 

 belong to the Chalk formation, as proved by their 

 organic contents, although commonly held to be 

 different from the Chalk, and considered as Ter- 



