190 M. Brongniaut on the position 



slates, the smoke-grey compact limestones, &c. and that it 

 is consequently inferior, like all these rocks, to the serpen- 

 tine formation. 



I might multiply citations and consequently resemblances ; 

 fent those that I should add not affording any thing more 

 striking than the preceding, I conceive that I have suf- 

 ficiently made these rocks known, to be able now to compare 

 them with those generally noticed ; some under the name of 

 transition rocks, others by those of Alpine limestone or 

 inferior sediment rocks. 



§ II. Comparison of these rocks zcilh the transition jacks 

 inost generaUy ddmitted as such. 



If in the first place we compare the rocks we have de- 

 scribed with those that almost all geologists refer to the 

 transition epoch, we shall find but very little resemblance 

 between them. 



We in fact see in the Apennine formations greyish rocks 

 of pure compact limestone, but without any crystalline 

 appearance in its paste, passing on the contrary to the schis- 

 tose texture and marly state ; sometimes arenaceous and 

 micaceous rocks, always calcariferous and nearly marly, not 

 containing any organic remains resembling those that are 

 admitted to be found in the transition rocks, being very 

 regularly stratified and often nearly horizontal, containing 

 hornstone either in their mass, or in the rocks which occur 

 with them in parallel and continuous stratification ; not con- 

 taining, in the numerous places where I have been able to 

 observe them beneath the serpentines, any of the metals so 

 common in the transition rocks, &c. 



What relation, I say, can be found between these rocks 

 and the transition formations of argillaceous schists, pure 

 spangled clay slates, i. e. not calcareous, containing schis- 

 tose jaspers and aluminous slate, alternating with the black 

 sublamellar limestones almost always fetid, containing lead 

 and zinc ores, anthracite, &c. and which is seen in England 



