234 UPPER SANDSTONES. 



nearly excludes the quartz, producing limestones. The 

 ,-- green colouring matter^consists of small grains, some- 

 times extending to the chalk above, producing the 

 j/> chloritic chalk of the continent, and also to the strata 

 beneath. It also contains mica, with beds of chert 

 and veins of chalcedony, cherty flints, and beds of marl 

 and of clay. Like all the other sandstones, it is occa- 

 sionally a conglomerate. Though the characteristic 

 colour is an obscure green, it is sometimes whitish, 

 grey, yellowish, or brown. Crystals of quartz, and of 

 calcareous spar, with pyrites and sulphate of barytes, 

 also occur in it, with rare lignites and silicified wood. 



The organic animal remains are very numerous. In 

 the number of its alcyonia it approaches 1:o the chalk, 

 and it contains also many echini, with a ff rw remains of 

 corallines and encrinites, and of fishes' tee th. For these 

 and its numerous shells, I shall howeve r refer to the 

 authors so well known. 



On the sandstones which occur above the chalk, or 

 in the tertiary formations, I need make no further re- 

 marks than those formerly g;iven in the chapter on 

 that subject ; referring to the authors who have de- 

 scribed these, for details not he: re admissible. 



