270 STUDIES OF NATURE. 



the level of the Se^ up to that of the Land. The 

 thickeft are undermoft, and the fmaller a-top, 

 which, from the fea-mark, makes the aggregate 

 appear higher than it really is ; as if Nature in- 

 tended to employ a certain degree of perfpedlive 

 to increafe the apparent elevation : but, imdoubt- 

 edly, fhe has been determined to adopt this ar- 

 rangement from reafons of folidity, which are per- 

 ceptible in all her Works. Now, thefe banks of 

 marl and flint are filled with fhells, which have 

 undergone no alteration from the force of fire, and 

 which would be in perfe6t prefervation, had not the 

 prefTure of that enormous mafs broken in pieces 

 the largeft of them. I have feen fragments ex- 

 trafted of that which is called the tiiilée^ which is 

 found alive only in the Indian Ocean, and the 

 broken pieces of which, when put together, formed 

 a (hell much more confiderable than thofe of the 

 fame fpecies which are ufed for holding the holy 

 water, in the church of Saint-Sulpice, at Paris. 



I have, likewife, remarked there a bed of flints 

 completely amalgamated, and forming a fingle 

 table, the feftion of which was perceptibly about 

 one inch thick by more than thirty feet in length. 

 It's depth in the cliff I did not afcertain; but, 

 with a little art, it might be detached, and fa- 

 fliioned into the mod fuperb agate table in the 

 world. Wherever thefe marls and flints are found, 



fhells 



