350 FOSSIL-SHELLS, ETC. 



and the whole plain is composed of the same materials, 

 which are shells of various kinds, without the smallest por- 

 tion of earth between them. Here then is a large space, 

 in which are deposited millions of tons of shells, that pil- 

 grims could not have collected, though their whole employ- 

 ment had been nothing else. England is furnished with 

 its beds, which, though not quite so extensive, yet are 

 equally wonderful. "Near Reading, in Berkshire, for 

 many succeeding generations, a continued body of oyster- 

 shells has been found through the whole circumference of 

 five or six acres of ground. The foundation of these shells 

 is a hard rocky chalk ; and above this chalk, the oyster- 

 shells lie in a bed of green sand, upon a level, as nigh as 

 can possibly be judged, and about two feet thickness.' 7 

 These shells are in their natural state, but they were found 

 also petrified, and almost in equal abundance in all the 

 Alpine rocks, in the Pyrenees, on the hills of France, Eng- 

 land, and Flanders. Even in all quarries from whence 

 marble is dug, if the rocks be split perpendicularly down- 

 wards, 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 continued for three feet and a half deep, or more, 

 and then beneath appeared a hard floor, or pavemeril, com- 

 posed of petrified shells crowded closely together. 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 color of marl ; and they themselves, 

 also, till they were washed, were of the same color ; but 



