169, UPPER, OR FLINTY CHALK. 



Tab. XV. fig. 4, represents a vertical section of a similar specimen. 

 Localities. Chalk-pits near Lewes. 



8. Flints deriving their form from alcyonia. Org. Ron. Vol. ii. 

 Tab. U. 



These are frequently met with on the ploughed lands of the South 

 Downs, and in all probabihty are the remains of alcyonia enveloped in 

 flint. 



Kolled chalk flints of a depressed, subrotund, hemispherical, or oblong 

 form, containing a body of a spongeous texture, are not unusual among 

 the pebbles on the sea-shore ; they are similar to the specimens figured 

 by Mr. Parkinson : the substance which they enclose is evidently of 

 alcyonic origin. 



Locahties. The shore at Newhaven, and along the coast to Beachy 

 Head. 



9. Bodies of a depressed, spheroidal, or subconical form, consisting of 

 a plexus of fibres, ramifying in a spongeous mass ; their constituent sub- 

 stance, a friable carbonate of lime. 



These frequently form the nuclei of sihceous nodules. 

 Localities. In the upper chalk near Lewes and Brighton, and on 

 the ploughed lands of the Downs. 



10. Pyriform bodies, the nature of which is vmknown. Tab. xvi. figs. 

 17, 18. 



These fossils are of a pyriform shape, sUghtly furrowed longitudinally, 

 and composed of flint, coated with a calcareous crust; when viewed 

 through a lens, their surface exhibits a spongeous structure. 



They are sohd, and exhibit some indications of a pedicle oi* process of 

 attachment. 



Localities. In the chalk near Brighton, first noticed by Col. Birch of 

 Bath. 



11. Spongia ramosa. Tab. xv. fig. 11. 



The remains of tliis fossil are probably more abundant in the flints of 

 the upper chalk, than those of any other zoophyte. The specimens ge- 

 nerally consist of cylindrical fragments, from J2 to S inches in length, and 0*6 



