378 BOARD OF AGRICULTURE. [Pub. Doc. 



were left so beset with the irrregularly disposed drift 

 materials that thousands of water basins were formed, vary- 

 ing in area from a fraction of an acre to several square miles. 

 When the ice went away from this district, these drift- 

 formed lakes were far more numerous than at the present 

 day. More than three-fourths of them have ceased to 

 appear as lakes ; they have in part been filled by accumu- 

 lations of peaty matter, in part they have been drained by 

 the cutting down of the frail barriers, a process arising from 

 the outflow of the storm waters which drained from them. In 

 both these cases the original lake has its situation indicated by 

 a soil deposit of a peculiar peaty nature. In certain rare 

 cases peaty accumulations have been formed on surfaces of 

 gentle slope which are underlaid by clay, or other imper- 

 vious materials of the under earth. In these cases the water 

 has been held upon the surface by the tangle of vegetable 

 growth. In these instances, as well as the foregoing, the 

 defective drainage is in practically all cases due to the alter- 

 ation of the pre-glacial declivities of the country to a lesser 

 slope, owing to the disposition of the glacial drift. 



The Swamps of Massachusetts. 

 The fresh-water swamps of Massachusetts are very widely 

 distributed. Reckoning those of all sizes, they are to be 

 numbered by the thousand, and are found in greater or less 

 abundance in every town and city of the Commonwealth. 

 Counting only those of sufficient area to have some impor- 

 tance with reference to the present or future agriculture of 

 the region, the total must be reckoned at an average of not 

 less than a score for each town. A close survey might 

 double this reckoning. There are indeed few farms in the 

 Commonwealth having an area of as much as a hundred 

 acres where patches of the soil are not more or less affected 

 by swampy deposits. Including in the account the marine 

 marshes hereafter to be noted, the total area of Massachu- 

 setts lands which are rendered untillable by excessive 

 humidity probably amounts to not far from five hundred 

 square miles, though this total includes some areas which 

 are covered by the shallow waters of lakes. It all may be 

 regarded as winnable land. 



