222 



AGRICULTURE. 



BOOK 1. 



be desirable to summer-fallow it for one or more seasons after 

 it is embanked. At other times, it may be better to sow it 

 with rapeseed for the first season, and to summer-fallow it the 

 next, as preparatory to a corn crop, &c. 



No kind of land can be gained from the sea but what is of 

 great value, in consequence of this peculiar circumstance, that 

 it can be flooded most generally by fresh water as well as by 

 the sea at all times. By flooding, the most barren sand or 

 rock, with only an inch or two of soil, will bear excellent pas- 

 ture. Indeed, much of the sand that is often reckoned barren 

 and useless, is mixed with broken shells, and, upon examina- 

 tion, will be found to contain three or four parts in ten of cal- 

 careous earth. Most of the large rocks within the salt water 

 mark are in a state of rapid decomposition, and so fragile on 

 the surface, as to be easily penetrated by the roots of grasses ; 

 more particularly after they have been exposed a year or two 

 to the action of the atmosphere. I do not here mean the large 

 detached stones that we often find within the water-mark; 

 these I suppose to be either buried in the ground, or boated off as 

 before mentioned; but those continued rocks which frequently 

 constitute the basis of the sea-shore for several leagues toge- 

 ther, and the surface of which is so completely oxydated and 

 sometimes decomposed, (in which state they are vulgarly called 

 rotten) that they will yield either ari excellent manure for cer- 



