176 Mr. Webster on the Strata lying over the Chalk, 



tions of the chalk formation, or those which immediately suc- 

 ceeded it. 



Some appearances shew that a similar action had taken place on 

 the original surface of our chalk. Many very interesting sections 

 may be seen in the County of Kent, where the chalk being at no 

 great depth, its junction with the strata over it may be very conve- 

 niently studied. At Woolwich, on the top of the chalk, and be- 

 tween it and the superimposed sand, there are a number of flint 

 nodules heaped on each other, which have evidently been displaced 

 from their original matrix. In the numerous chalk pits, and where 

 the roads are cut through the chalk along the south side of the 

 Thames, as at Rochester, Gravesend, North Fleet, Greenhithe, &c. 

 the junction of the chalk with the sand and gravel is remarkable for 

 the deep indentations in the surface of the former, which upon ex- 

 amination I ascertained to be the sections of long furrows and of 

 wells ; these were apparently occasioned by the powerful action of 

 water prior to the deposition of the sand and gravel which now fills 

 up these hollows : the same may be seen still better at Purfleet. 



The present surface of the chalk stratum is also frequently covered 

 by water-worn pieces of chalk and flint imbedded in clay or alluvial 

 deposits. 



The cliff's between Brighton and Rottendean are of a singular 

 character, and merit a particular description. The shore consists of 

 the solid chalk, which is seen running out to a considerable distance 

 into the sea, and dipping a few degrees to the south. This stratum 

 forms six or seven feet of the lower part of the vertical cliff"; and 

 on that are placed several layers of loose flints, evidently rounded 

 by attrition and piled on one another. Over this is an irregular 

 bed consisting of pieces of chalk and smaller pieces of flints, both 

 of which have undfirgoa.^ the same process ; and the interstices are 



