ECONOMICAL GEOLOGY. 73 



Mr. Edmunds says of this soil : " It has been worked for 

 the last hundred years, as I am informed on the best au- 

 thority, without any vegetable or mineral matter whatever 

 being put on it. It has been under cultivation in corn, 

 wheat, rye, oats, and potatoes, successfully, every three and 

 four years, from the time spoken of until the present. I 

 am not aware of its being impoverished by this mode of 

 cultivation since my knowledge. I have found the crop 

 to be as good the last season as it was the first that I knew 

 it. The area of that part of the field so productive is about 

 five acres. In many places the soil is shelly ; so much so, 

 that it requires some skill to manage the plow. The sub- 

 soil is deep, with a black sandy mould. I think the shells 

 have been in some way the cause of the productiveness of 

 this field." 



The analysis of a soil which has been under constant 

 cultivation for a hundred years, with a three or four years' 

 rotation of field crops only, and which still produces fifty 

 bushels or upwards of corn per acre, is worthy of notice. 



The following are analyses of the deposits on the salt- 

 marshes. They can hardly be called soils at present, but 

 with an improved agriculture they must yet become the 

 most valuable and productive in the county j and they are 

 also the repository of vast stores of fertilizing materials for 

 improving upland. 



