214 PETRIFACTIONS AND THEIR TEACHINGS. CHAP. III. 



Passing near Bletchingley, in Surrey, through a tunnel 

 in the Wealden, we arrive at Balcombe, in Sussex, where 

 laminated sandstones and shales are seen on each side the 

 cutting. The general dip of the strata hitherto passed is to 

 the north-east; but after crossing the deep Wealden valley 

 beyond Balcombe, over a magnificent viaduct, the line runs 

 along alternating layers of sands and clays, which dip to the 

 south-west; we have therefore arrived on the southern side of 

 the grand anticlinal axis of the Forest Ridge excavated by the 

 tunnel through which we passed. 



The Wealden strata continue with the same general inclina- 

 tion by Hay ward's Heath, 1 which is traversed by a tunnel, to 

 beyond St. John's Common, (formed of Weald clays and 

 Sussex marble,) where they disappear beneath the lowermost 

 greensand beds of the Chalk formation. The gait, firestone, 

 and chalk-marl succeed ; and, lastly, the white chalk of the 

 South. Downs, at Clayton Hill, through the base of which 

 a long tunnel is carried, and emerges on the Downs on the 

 south. The remainder of the line to the Brighton station, 

 runs over, or through, hills and valleys of the white chalk. 



Thus this railway passes through two ranges of chalk hills, 

 viz. the North and South Downs, by tunnels ; two of green- 

 sand, viz. near Red Hill in Surrey, and Hurstperpoint in 

 Sussex ; and two principal ridges of Wealden, viz. at Balcombe, 

 and Hayward's Heath. There is not a railroad in the king- 

 dom that in the distance of fifty miles exhibits geological 

 phenomena of greater interest. 



If we take a line bearing more to the west, as, for example, 

 from London to the southern shore of the Isle of Wight, at 

 Sandown Bay, we shall have the section represented in 

 Lign. 46, which exhibits the entire series of the deposits, and 

 their relative position. 



JOURNEY FROM LONDON TO BRIGHTON BY COACH. It may 



Sussex, are Tower Hill quarry, Stammerham quarry, and other pits in 

 which the Tilgate grits and sandstones are exposed, and where the 

 characteristic fossils of the strata may be obtained of the workmen ; 

 wit] i bones of the Iguanodon, Goniopholis, and other Saurians, stems 

 of Clathraria, &c. See my " Geology of the S. E. of England," p. 212, 

 or " Wonders of Geology," sixth edition, p. 372. 



1 Hayward's Heath station is within 1 J mile of Cuckfield, which lies 

 to the right of the line. 



