22 



OUR COMMON BRITISH FOSSILS. 



near Lewes, Spongites ramosus may be gathered, 

 twelve to fifteen inches long. In many places, as in 



Fig. 13. Horizontal section of Flint, 

 containing Choanite, or lower part 

 of Ventriculite, showing sponge 

 foldings. 



Fig. 14. Longitudinal section of 

 Ventriculite imbedded in flint. 



Fig. 16. Ventriculite in Flint, 

 showing external markings in 

 upper part- 



Fig. 15. Longitudinal section 

 of Ventriculite in flint-nodule, 

 showing roots. 



any chalk pit on Salisbury Plain, the collector finds 

 that nearly every flint is " rotten ; " the branching 



