ENGLISH CHALK DOWNS. 205 



and calcareous slime settled down together in a 

 soft and mingled mass of mud ; but gradually, as 

 time went on, the flinty particles collected to- 

 gether into solid veins and lumps, while the wliole 

 material was still in the plastic and almost liijuid 

 condition, exactly as the sugar in currant jelly 

 often crystallizes out into little nodules, dispersed 

 irregularly through the surrounding mass. 



In process of ages the cretaceous sea under- 

 went great changes, and the whole immense 

 layer of chalk, then stretching unbroken over 

 enormous districts of England, France, Holland, 

 and Belgium, came to be overlaid by the newer 

 deposits of the tertiary seas, which once, no 

 doubt, completely covered it in every part. Later 

 still the work of elevation began, and (with many 

 minor vicissitudes which need not here be de- 

 tailed) Eastern England rose at last above the 

 level of the sea. At that time, without question, 

 the chalk was still unbroken between Dover and 

 Calais. The North Sea and the English Channel 

 had no existence, and the white cliffs of perfidious 

 Albion had not yet begun to be formed and un- 

 dermined by the encroaching waves. But with 

 the advance of the ages the waters of the Atlantic 

 began their long aggressive movement upon the 

 broad belt of soft chalky strata which then con- 

 nected the South and East of England with the 

 opposite shore of France and Belgium. Slowly 



