1(58 



6. The Upper Greensand consists of a siliceous Sand or 

 calcareous Sand, with gi-een grains. It often contains nodules 

 of Chert and masses of Limestone, and concretions containing 

 phosphate of Lime, which are probably coproUtic in their 

 character, and valuable to the agriculturist. It is well exposed 

 at Warminster and Devizes, in Wilts ; in the Isle of Wight ; at 

 Charmouth, Dorset ; and in Cambridgeshire. 



6. The Chloritic Marl appears to form a poi-tion of the 

 previous formation. It is a light-coloured Marl, fuU of green 

 specks of sihcate of Iron, with numerous fossils ; and is exposed 

 at Chard, Chardstock, and St. Catherine's Down, Isle of Wight, 

 where it is above 150 feet thick. The Upper Greensand is the 

 equivalent of the Glauconie crayeuse of the French, the Tourtia 

 of the Belgians, and the Etage Cenomanien of D'Orbignt. 

 Covering all these, more or less argillo-arenaceous formations 

 just described, is the Chalk proper, which is divisible into Chalk 

 Marl, White Chalk without flints, and White Chalk with flints. 



7. The Chalk Marl consists of hard Chalk, passing sometimes 

 into Chalk Marl or hard gray Chalk. The transition from the 

 Upper Greensand into this formation is sometimes so gradual 

 that it is difficult to define the hne of separation. It is well 

 developed at Dover, Folkestone, Kent, and Lewes, Sussex, and 

 at Swaffham, Norfolk. The Chalk Marl is the Planer of the 

 Gennans, the Craie tuffeau of the French, and the Etage Turonien 

 of D'Okbignt. 



8. The White Chalk without Flints is a great mass of soft 

 thick-bedded Limestone, with obscure indications of stratification 

 from the obhteration of the planes of bedding and the character 

 of the joints. It contaias numerous nodular balls of Iron 

 Pyrites, radiated mternally, which, on decomposing, produce 

 rusty stains on the rock. 



9. 2%e White Chalk with Flints resembles the preceding 

 lithologically, but differs from it in containing rows of nodules 

 of black FKnt, interstratified at certain distances apart, or 

 having occasionally tabular layers of dark Silex coincident with 

 the plane of stratification, or seams of the same extending along 

 the line of bedding. The White Chalk itself is nearly a pure 



