372 



PEOCEEDZN-GS OP THE GEOLOGICAL SOCLEIT. [April 2: 



4tli. All ockreous yellow ; and, 

 5th. A light neutral grey. 



Pig. -45. — Section of tlie Argile plastique and Calcaire grassier 

 exposed in day-ijit, Vaugirard, Paris. 



Calcaire grossier. 



Laminated clars. with 

 impure lignite. 



>-Argile plastique. 



^^ ^5^^ -^^ dialt, not visible in 



;^jeg-e -^r^'^S-^^i^rS"^^^ ^r\ *^^ section. 



At the base (c), the blood-red primordial colour prevails \rith but 

 slight variegation ; towards the middle (h) the variegation becomes 

 more definite, consisting of distinct patches of grey on the red or 

 pink ground, each of which concentrically surrounds a nucleus of 

 dark brown and red, as shown in fig. 21 (Plate XIII.), and is more 

 or less mottled with ochreous yellow. As the carbonaceous beds 

 are approached, the blood-red gradually dies out into neutral grey 

 through intermediate shades of piuk ; and the uppermost portion (a) 

 is variegated only by isolated brown blotches on a uniform grey 

 ground, such as lower down formed the nuclei of the grey patches. 

 The proportionate amount, and the state of combination, of the iron in 

 these five shades of colour will help to explain the character of this 

 curious and complicated variegation. 



The blood-red portions , of the clay, which are evidently in its 

 primordial condition, contaia : — 



(Analysis No. 53, by Dr. Yoelcker) Protoxide of iron 0o48 per cent. 



Anhydroiis sesquioxide 19(>41 „ 



Orsranie matter 0320 .. 



