XIII.] SLOW MOVEMENTS OF THE LAND. 



215 



thrown into a succession of sharp anti- 

 cHnals and synclinals. 



During the disturbances to which strata 

 have been subjected since their original 

 deposition, it has frequently happened 

 that the rocks have been broken and dis- 

 located, as represented in Fig. 10, p. 30 ; 

 where the series of beds, on one side of 

 the fracture or fault, have been thrown 

 down to a much lower level than that 

 occupied by the strata on the opposite 

 side. Even in an area so little disturbed 

 as the London basin, such dislocation of 

 the strata may be detected ; and, indeed, 

 a considerable fault runs along part of the 

 valley of the Thames below London, and 

 throws down the beds on the north to the 

 extent of 100 feet, or even more. Before 

 leaving this subject, it may be well to 

 mention that contortion and dislocation 

 of strata may be due to squeezing at the 

 sides, and not to the direct operation of 

 forces acting immediately from below. 



From what has been said in this chapter, 

 it will be seen that deposits, formed origi- 

 nally on the floor of the sea, have been 

 hoisted above water, and now form the 

 bulk of our dry land. The land is there- 

 fore subject to a kind of circulation similar 

 to that which has been already pointed 

 out in the case of water. The water, it 

 will be remembered, passed from the river 



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