148 M. Charbaut on the 



that none can be distinguished in fresh fractures of the rock ; 

 some large pecteus, belemnites, and terebratulae can only be 

 perceived. 



At a considerable height, beds of granular limestone are 

 found full of circular and small smooth pectens, of the size 

 of a lentil ; afterwards a grey compact limestone always with 

 flint nodules, containing large imbricated pectens, and a 

 longitudinally striped bivalve, referable to the genera mactra 

 or venus. The valves of this shell, without being separated, 

 appear to have been turned over the plane of their junction, 

 so that the teeth no longer correspond ; large bivalves are 

 also seen with deep folds, the genus of which it has as yet 

 been impossible for me to discover. 



Among these last beds there is one, the rock of which 

 perfectly resembles the gryphite limestone, and which is 

 surprisingly rich in marine fossils ; besides the greater part 

 of the shells that I have already noticed, I have found very 

 fine orbulites in it of the size of an egg, which I have not 

 elsewhere met with ; an undetermined fragment of an or- 

 ganized body of the size of an arm, having a bony texture, 

 and in this respect analogous to a much smaller fossil, which 

 I found in the department of the Doubs, and which bears 

 some resemblance to the spine of a sea fish, of a species of 

 sting ray (raie aigle) ;* fragments of a very large bivalves 

 are seen, the shell of which is more than five millimetres [i 

 inch] thick, with traces of many other animals, t 



The compact limestone afterwards becomes very siliceous, 

 and contains no shells, for a great height ; it is transformed 



* May not this be the same kind of bone which I have described as 

 the radius of some fish in the first vol. Geol. Trans, new series, p. 43,44, 

 and figured pi. 4, different species of which are found in the transition 

 limestone, carboniferous limestone, lias, oolite formation, and chalk? 

 (Trans.) 



+ Among the shells found in this rock, and of which very 'ew of the 

 species are described, or in a state to be determined, ammonites discus 

 of Sowerby may be noticed, which I have found in the ferruginous 

 oolitic rock of Aisy in Burgundy. The pecten lens. Sow. is also found in 

 Burgundy in the same rock and with the same shells. 



