64 RAMBLES AND REVERIES. 



rear themselves up almost perpendicularly from 

 high-water mark, aud distinct bands of different 

 cretaceous deposits can be seen. At the bottom, 

 lying on the Gault, is a thin layer of chalk marl, 

 next above which is a thick band of grey chalk, the 

 delight of the tunnellist, and after this comes an 

 important deposit of white chalk without flints, 

 composed mainly of crumbled foraminifera and 

 mollusca, presenting under the microscope a re- 

 markable similarity to the deep sea ooze of our own 

 time ; while last of all is a layer of nodular chalk 

 containing many flints. It is said that these nodules 

 are simply petrified sponges, and that flints are of 

 similar origin. These animals yes, sponges are 

 animals long before we were born secreted great 

 quantities of silica from the water of the ancient 

 seas, which after the death of the sponges became 

 a nucleus around which were aggregated other 

 elements by chemical agencies, the whole hardening 

 afterwards into the unbreakable flints that are so 

 cordially hated by those who have the management 

 of the cutters in the Channel Tunnel operations. 

 But this is not the only theory afloat concerning 

 the origin of flints. 



Near Lydden Spout some idea of the action of 

 the sea in wearing down rocks may be obtained. 

 A very useful path winding down from the coast- 

 guard station to the beach below has been quite 

 washed away for some distance at the bottom in 

 the space of a few months, and now the pedestrian, 

 if he should reach the spot when the water is coming 

 in, may find himself in serious difficulties. A little 



