80 



PROCEEDINGS OF THE GEOLOGICAL SOCIETY, 



the intermediate series of stratified gravels, with the lower beds called 

 Combe rock, a mixture of chalk and flint with yellow clay, have been 

 pitched and washed by pluvial action over the escarpment. These 

 materials, derived from the high ground behind the escarpment, and 

 thrown over it, have not been sufficiently water- washed, nor perhaps 

 even placed within the reach of water flowing sufliciently fast, to re- 

 move the angles of the soft chalk fragments ; nor has the act of depo- 

 sition abraded the edges of the flint, which are often splintered before 

 being bedded in the Combe rock. 



Fig. 11 is another view of the structure of the Brighton gravel- 

 bed, at a point a little to the west of fig. 10, where the escarpment of 

 the chalk must be very near the face of the cliff. The raised shingle- 

 beach is 6 ft. thick, and falls at 8° south to the sea. The position of 

 the present beach is shown 9 ft. below the ancient one. Dr. 

 Mantell first obtained remains of Elephas, from these deposits, near 

 Sussex Square ; but no shells have yet been found in them. 



Pig. 12 has been, by mistake, reversed in the drawing, and is 



Fig. 12. — Vertical Section of Brighton Cliff. 

 E. w. 



e. Covering bed. 



Combe rock. 



c. Stratum of chalk boulders. 



6. Ancient shingle-beach. 



a vertical section of the Brighton gravel-beds at a point intermediate 

 between that shown in fig. 10 and Sussex Square. By means of a 

 footpath up the cliff, I was enabled to determine the dip of part of 

 the middle series of gravels (d) to be 25° west. The covering bed 

 and gravel (e) and the raised beach deposited at the bottom (6) 

 appear quite horizontal at that point. 



The old beach (6) is about 7 ft. thick, and the chalk boulder- 

 bands (c) interstratified with flints about 9 ft. thick, the cliff being 

 about 63 ft. high. 



Fig. 13, on a larger scale, exhibits a front view of the cliff 100 

 yards east of the Rottingdean landing-place, three miles east of 

 Sussex Square, Brighton. This is near the termination of the 

 Brighton gravel- deposit ; and I have drawn it to show the manner 

 in which the gravel reposes in a hollow of the chalk, formed by a 

 stream which reached the sea at Rottingdean in the gravel-period. 



