186 M. Brongniart on the position 



geologists, the limits that I have assigned these different 

 sediment formations. 



The inferior sediment formation extends from the last 

 transition rocks to the graphite limestone inclusive. It con- 

 tains the coal measures especially, the alpine limestone of 

 the German geologists, and* the lias and mountain limestone 

 of the English geologists.t 



The middle sediment formation extends from the pre- 

 ceding limestone to above the chalk, and principally con- 

 tains the compact, whitish, and oolitic limestone of the Jura, 

 and the chalk. It is a very extensive formation, to which I 

 shall hereafter have occasion to return in another memoir.]: 



The superior sediment formation, also named tertiary for- 

 mation, extends from the chalk exclusively, or from the 

 plastic clay and lignites exclusively, to the surface of the 

 earth, of rather to the last marine deposits of the ancient 

 sea. 



The formation beneath the serpentines may either be re- 

 ferred to a transition formation, or the inferior sediment 

 formation. Whatever may be the opinion adopted, a new 

 fact in geology must always be admitted, i. e. a transition 

 formation very different by its characters from those gene- 

 rally referred to that series, or serpentines and diallage rocks 

 of a new formation, since, in the second hypothesis, they 

 would be at least posterior to the inferior sediment or Alpine 

 formation. 



The first idea that presents itself, that which a justly 

 celebrated Italian geologist, M. Brocchi, has entertained 



* I have inserted the word " and, " conceiving that M. Brongniart 

 does not confound the lias and mountain limestone. (Trans.) 



t The inferior sediment formation of the author therefore consists of— 

 old red sandstone ? carboniferous, or mountain limestone, millstone grit, 

 coal measures, magnesian limestone (Alpine limestone of the Ciermans), 

 saliferous, or new red sandstone, and lias. 



:|: The middle sediment formation therefore consists of the oolite for- 

 mation, from the inferior oolite upwards, the beds between the oolites 

 and ohalk, such as the iron sand, weald clay, and green sand, and the 

 chalk formation. 



