LOWER CRETACEOUS STRATA. 



!S ] 



at the time when these cretaceous beds began to 

 be formed. There are thus sands in the west in 

 set and Devon, which appear to represent a 

 part, if not the whole, of the Ciault ; perhaps the 

 Upper Gault, and the Upper Greensand. There 

 is a Red Limestone in the north-east from Norfolk 

 to north of Flamborough, which is a similarly un- 

 divided deposit. Placed geographically between 



these sands in the SOUth-west and limestone in the 



north-east, are the strata known as Gault and 

 ensand. 

 I ie 6 ■ rests on Lower Greensand and Neo- 



;:an Sands. It is a blue micaceous clay, dark 

 in colour in the lower part, where it is rich in fos- 



. and full of layers of concretions of phosphate 



of lime, w:. amount of iron 



pyrites in - calities. Its thickness in the 



rj is about 150 feet, but it thickens 



to more than 200 feet at Hitchin; and one boring 

 Soham is said to have passed through 450 feet 



Fig. 2 ■■>. — Cliff section. Hunstanton. Norfolk. Upon the brown 

 omian San the red Hunstanton Limestone, four 



thick. The Lower Chalk rises from the beach to the top 

 of the cliff, the dip being east 



without piercing it. Yet it thins away in the south 

 of Norfolk, and there develops calcareous beds in 



