530 



from the formation appears to be governed by local phenomena. At 

 East Bergholl, a well was dug to the depth of 40 feet in London clay, 

 without success ; but in excavating a cellar a few feet from the well, a 

 copious spring was tapped, and conveyed into it by a channel. In the 

 river Ore is an island of London clay, in which two wells were sunk 

 through 80 feet of clay, 3 inches of rock and 20 feet of sand. The 

 water rose to the surface, had a strong smell of sulphur, but no saline 

 taste, though it overflowed only during high tide in the river. The 

 fossils mentioned by the author, are confined to fishes' teeth, and the 

 occasional occurrence of shells. He mentions that land animals have 

 undoubtedly been found in the London clay, as the tusk of an elephant 

 at Harwich, but he is of opinion that the greater part of such remains, 

 said to have been obtained from the formation, have been waslted out 

 either of the crag or the diluvium. 



Crag. — Mr. Clarke says the term crag is applied in. Sufl'olk only 

 to the shelly beds, and the word gravel to the associated beds of peb- 

 bles, as well as to the accumulation of superficial pebbles. The por- 

 tion of the county occupied by the deposit, is bounded on the west by 

 a line connecting the water-head of the estuaries ; and the most 

 southern point at which it is now visible is Blackbrooke Hill, near Ded- 

 ham, the patch at Walton Naze having been entirely removed by the 

 partial destruction of the cliffs. Sand, however, containing shells occurs 

 at Ardleigh Wood near Colchester, and it has been said that Danberry 

 Hill, near Chelmsford, is capped by crag; but Mr. Clarke doubts the 

 accuracy of this observation. The general surface of the area assigned 

 to the deposit in Suffolk, is a platform of nearly regular elevation, which 

 appears to have been worn into ridges and valleys by currents acting 

 in parallel lines from N.E.toS.W., and the cliffs both in the interior 

 and on the coast, are sections of these ridges. The dip of the London 

 clay corresponds with that of the crag, and therefore Mr. Clarke in- 

 fers, that both were acted upon by the same agents, and while they 

 were beneath the level of the sea. 



According to the author's observation, the deposit nowhere extends 

 more than twelve or thirteen miles from the coast, and at Pakefield, 

 where the diluvial clay comes to the very edge of tlie sea, it disappears 

 as a surface deposit, but is visible at intervals further north, between 

 that point and Cromer. Mr. Clarke also states, that though undoubt- 

 edly crag is discernible here and there, in situ, as a regular formation 

 north of the Waveny, yet he by no means allows that it is regularly 

 stratified, as an undisturbed deposit, between Leiston and Pakefield. 

 He is fully convinced from observation, that the diluvial clay and crag 

 are distinct deposits ; and he is almost equally convinced, that if the 

 crag has any share in the formation of the cliffs between the Blithe 

 and Lake Lothing, it has been introduced by disturbances of a similar 

 nature to those, which are presented in the cliffs of East Norfolk. 

 Thai the localities in dispute may have been once occupied by crag, 

 there is no reason to deny, but they now present no traces of an undis- 

 turbed deposit. 



To previous descriptions of the structure of the crag, the author 

 sLates that he has nothing to add, except that where the shells are 

 not visible, the sands contain a slight mixture of calcareous matter. 



