504 ' DOMAIN V. CALCAREOUS. 



MODE XL CHALK. 



Characters. Texture earthy, rather fine, on a large scale 

 generally stratified, with interposed layers of 

 detached flints at regular intervals. The flint is 

 sometimes schistose and continuous, as in the 

 neighbourhood of Margate, and the North Fore- 

 land. 



Hardness, of course, cretic. Fracture, even, 

 earthy. Fragments amorphous, blunt. 



Weight, pumicose. 



Lustre, dull. Opake. 



The colour is a dull white, proverbially known, 

 but, wanting the brightness of alabaster, has 

 never been used to celebrate the charms of 

 beauty. From the decomposition of the balls 

 of iron pyrites, which it often contains, it may 

 in parts assume a yellowish or greyish tint. 

 Sites. Chalk not only forms rocky cliffs, of a most 

 regular, bright, and imposing aspect; but may 

 be said to constitute whole regions. A large 

 portion of the south of England, and the north 

 of France, consists of chalk ; which, in Hamp- 

 shire and Kent, is often covered with the hop ; 

 and in Champagne affords a light vivacity to the 

 vine. It also appears in the flat islands of Den- 



