78 



PKOCEEDINGS OF THE GEOLOGICAL SOCIETY. 



which, according to Dr. Blackmore, are associated with, flint instru- 

 ments of the Amiens type. 



Land and freshwater shells are very- 

 abundant. The great shell-bed is near 

 the chalk, lying upon a bed of gravel ; 

 and the Pupa-bed touches the lower sur- 

 face of the covering bed of gravel, e. 

 While the curve of the surface is on the 

 average 3° between A and B, the dip of 

 the lower gravel, 6, where it touches the 

 escarpment of the chalk, will probably 

 lie at a very steep angle. 



The Pupa-bed, c, a fine loess, is marked 

 by a distinct band of colour ; it is about 

 2 ft. thick, and slopes to the river in a 

 gentle curve. I have marked its dip 

 16°, then 11°, then 9°. The bed c con- 

 tains only six species of shells, Helix 

 arhustorum (?), Helix hispida, Zua lu~ 

 brica, Lymnoea palustris, Yalvata pisci- 

 nalis,Pisidium obtusale, besides the Pupce 

 in immense abundance. The lower band 

 h contains thirty-one species of terres- 

 trial and fluviatile shells, according to the 

 lists of the late Mr. John Brown and Dr. 

 Blackmore. 



The chalk, a, is 30 feet from the sur- 

 face at A, but in 30 yards it reaches the 

 surface ; so that the escarpment in the 

 part not yet opened is known to be at 

 an angle of 30°, sloping towards the 

 river. As is usual, the brick- earth is 

 thickest a little way from the escarpment, 

 and passes, on the same horizon, into 

 gravel and sand as you approach the 

 river. 



The remains of another arctic mammal 

 (the Musk-Ox) have been recently found 

 in the loess at Salisbury. This animal 

 is now living in a remote part of North 

 America. The stratification at Salis- 

 bury, shown in fig. 9, is very similar to 

 that at Erith, fig. 17. 



The mammalian gravel and Combe rock extends from Brighton, 

 without interruption, to the point drawn, fig. 10, and presents a clifi" 

 of roughly stratified beds facing the sea, about 60 ft. in height.^ 



The escarpment of the chalk is known to be not far distant in the 

 rear of the present face of the cliffs at any point ; and an extensive 

 fall of gravel has exposed the escarpment of chalk. In the steepest 



