42 HISTORY OF 



on the hills of France, England, and Flanders. 

 Even in all quarries from whence marble is dug, 

 if the rocks be split perpendicularly downwards, 

 petrified shells, and other marine substances, will 

 be plainly discerned. 



" About a quarter of a mile from the river 

 Medway, * in the county of Kent, after the taking 

 off the coping of a piece of ground there, the 

 workmen came to a blue marble, which conti- 

 nued for three feet and a half deep, or more, and 

 then beneath appeared a hard floor, or pavement, 

 composed of petrified shells crowded closely to- 

 gether. This layer was about an inch deep, and 

 several yards over ; and it could be walked upon 

 as upon a beach. These stones, of which it was 

 composed, (the describer supposes them to have 

 always been stones) were either wreathed as snails, 

 or bivalvular like cockles. The wreathed kinds 

 were about the size of a hazel-nut, and were filled 

 with a stony substance of the colour of marl ; 

 and they themselves, also, till they were washed, 

 were of the same colour ; but when cleaned they 

 appeared of the colour of the bezoar, and of the 

 same polish. After boiling in water they became 

 whitish, and left a chalkiness upon the fingers." 



In several parts of Asia and Africa, travellers 

 have observed these shells in great abundance. 

 In the mountains of Castravan, which lie above 

 the city Barut, they quarry out a white stone, 

 every part of which contains petrified fishes in 

 great numbers, and of surprising diversity. They 



* PhU. Trans, p. 426. 



