244 



MR. W. HILL ON THE BEDS BETWEEN THE 



applied ; and in defining the limits of the Middle Chalk of Dover it 

 appears necessary to consider the palaeontological position of that 

 hard bed to which the name " GlialTc Rock " has been given by Mr. 

 Whitaker. It is described by him * as ^' a hard cream-coloured 

 chalk with layers of irregular-shaped nodules, darker, generally 

 green-coated and slightly phosphatic; where best developed it is 



markedly jointed, breaks with an even fracture, and rings 



with the hammer." 



This OhalJc Rock as seen in the neighbourhood of Pangbourn 

 (Hart's Lock) and Henley is a compact band of hard rock in which 

 occur layers of green-coated brownish nodules. Where the section 



TJpPEE ChalkJ, 



Middle Chalk. 



Pig. 3. — Diagram showing the Rocky Beds above the " Chalk Rock^^ 

 from Sections seen at Chinnor, Aston, and Henley. (Scale 10 feet 

 to 1 inch.) 



Line of flints. 

 Tabular flint. 



Hard yellowish rock. 





Whitish chalk, with hard erystal- 

 i line lumps in soft mealy chalk. 

 Many Micrasiers and other 

 fossils. 



Frequently a flint line here. 



Hard rock, with layers of green- 

 coated nodules. 



Softer chalk, passing up into hard 

 r rock. 



/ Marly band. 



Memoirs G-eol, Survey, vol. iv. p. 40 



