66 ON A PIECE OF CHALK 



the smallest brook which feeds the swift stream of 

 " the great river, the river of Babylon," began to flow. 



Thus, evidence which cannot be rebutted, and which 

 need not be strengthened, though if time permitted 

 I might indefinitely increase its quantity, compels you 

 to believe that the earth, from the time of the chalk to 

 the present day, has been the theatre of a series of 

 changes as vast in their amount, as they were slow 

 in their progress. The area on which we stand has been 

 first sea and then land, for at least four alternations; 

 and has remained in each of these conditions for a 

 period of great length. 



Nor have these wonderful metamorphoses of sea 

 into land, and of land into sea, been confined to one 

 corner of England. During the chalk period, or "cre- 

 taceous epoch," not one of the present great physical 

 features of the globe was in existence. Our great moun- 

 tain ranges, Pyrenees, Alps, Himalayas, Andes, have 

 all been upheaved since the chalk was deposited, and 

 the cretaceous sea flowed over the sites of Sinai and 

 Ararat. 



All this is certain, because rocks of cretaceous, or 

 still later, date have shared in the elevatory move- 

 ments which gave rise to these mountain chains; and 

 may be found perched up, in some cases, many thou- 

 sand feet high upon their flanks. And evidence of equal 

 cogency demonstrates that, though, in Norfolk, the 

 forest-bed rests directly upon the chalk, yet it does so, 

 not because the period at which the forest grew imme- 

 diately followed that at which the chalk was formed, 

 but because an immense lapse of time, represented 

 elsewhere by thousands of feet of rock, is not indicated 

 at Cromer. 



