1 16 Dr. FiTTON on the Strata below the Chalk. 



The situation and relative space occupied by these subdivisions near Folk- 

 stonCj are shown in the small Map, Plate VII. fig. !._, and in the View, 

 Plate VIII. 



(17.) a. The uppermost subdivision is about seventy feet thick. It rises 

 upon the shore on the west of Eastware Bay ; and some of the firm siliceous 

 beds which it includes near the top, coming up from the sea a little to the 

 east of Copt Point, are continued in the cliff thence to the west of Sandgate ; 

 between which place and Folkstone distinct sections are disclosed. The 

 greater part of the country from Folkstone, through Cheriton, to Newington 

 is occupied by this bed, and the heights of Dibgate and Sine Farm, where 

 it finally disappears, are capped with it. 



(18.) Where the sand emerges from beneath the Gault, it is often loose, 

 and of a white or buff colour; but at the immediate junction there occurs, in 

 Tnany places, a course, from six inches to a foot in thickness, of concretions 

 of pyrites, often investing fragments of silicified coniferous wood, of a dark 

 brown colour. The composition of this bed resembles, in several respects, 

 that of the Blackdown sands in Devonshire, the stone which it includes con- 

 sisting principally of siliceous spongy concretions, like the whetstone of that 

 place. The most instructive specimens are to be found in the loose decom- 

 posed masses on the shore. In the vertical faces of the cliffs, the surface 

 exposed by fracture and falling away is at first clean and uniform, no traces 

 of the stratification appearing; but after a time the sand crumbles from the 

 surface, while the stony portions remaining fixed, become prominent. 



The whole of these cliffs consists, in fact, of sand and conglomerates more 

 or less firm, produced by the agglutination of the loose materials which formed 

 the original subnjarine deposit. The strata vary in texture and composition, 

 from the state of sand to that of very hard limestone or chert, of various 

 shades of grey and brown; the latter passing into chalcedony, with which the 

 cavities are sometimes coated*. The transition from the sand into compact 

 stone is sometimes very rapid ; in other specimens the gradations are almost 

 insensible. 



(19.) The principal components of these conglomerates are the following: 



1. Quartz, in rounded fragments, from the bulk of a large pea to the 

 minutest visible size, of several shades of grey and white, varying from trans- 

 parent to nearly opake, and in some instances passing into chalcedony. 



2. Small, worn fragments of quartzose jasper, red, or greenish ; with flat 

 surfaces, in some cases, indicating stratification. 



* It is remarkable, that notwithstanding the abundance of siliceous matter in the concretions 

 near Folkstone, few or none of the petrifactions are formed of it ; while at Blackdown in Devon- 

 shire most of the shells in this formation are casts in chalcedony. 



