PBESTWICH CRAG-BEDS OF StTPFOlK AND NOBFOLK. 



477 



but still leaving land in the near vicinity. Prom this land wood 

 and freshwater testacea, and some mammalian remains were carried 

 down into the great beds of shingle forming off the coast in a sea in 

 which still lingered some of the Crag MoUusca. At the same time 

 a portion of the old forest land as well as of the marine clays 

 which preceded it were denuded. These sands and shingle are 

 of much greater extent than the forest- area, and spread over all East 

 Norfolk, Suffolk, Essex, and beyond. The main feature of this 

 deposit is the presence of flint pebbles with a considerable proportion 

 of white and pink quartz pebbles and a few pebbles of slate, toge- 

 ther with some rolled fragments of Greensand chert. On the table- 

 land above the Meuse, in Belgium, there is a gravel of a very similar 

 character ; and I think it not improbable that some old river tra- 

 versing the Ardennes may then have brought down into this Crag- 

 sea area the old slate, quartz, and quartzite pebbles found so abun- 

 dantly in the Westleton shingle, while other streams from the south 

 or south-west may have drifted in the chert from the Lower Green- 

 sand and the mass of flint pebbles from the Chalk *. 



The relation of the Crag sea of Belgium with that of the south- 

 east of England has been the subject of frequent inquiry. Taking 

 the revised lists of M. Dewalque and those at the end of this paper, 

 the following results are arrived at respecting the species common 

 to the several deposits. 



Numerical Distribution. 





Total. 



Sables gris. 



Sables jaunes. 



Sables noirs. 



Norwich Crag 



Suffolk or Eed Crag 

 Coralline Crag 



155 

 273 

 316 



60 

 122 

 133 



68 

 138 

 135 



24 

 61 

 98 



Proportional Distribution. 





Sables jaunes. 



Sables gris. 



Sables noirs. 



Norwich Crag 



Suffolk or E«d Crag 

 Coralline Crag 



43-9 

 50-5 

 42-7 



38-7 

 44-7 

 42-4 



15-5 per cent. 

 22-3 „ „ 

 31-0 „ „ 



This shows a more marked connexion between the upper or Eed 

 and Norwich Crags and the Sables jaunes and. gris, forming the Systbme 

 Scaldisien of Dumont, than was before noted ; whilst the lower or 

 Coralline Crag seems to hold a place intermediate between these 

 beds and the Sables noirs, or the Systeme Diestien of Diimont. 



Such, then, are some of the changes which mark the epoch of the 



* I have also met with rolled fragments of silicified wood, like that which I 

 have found in situ in the Woolwich and Reading Eocene series of Kent. 



