242 BOARD OF AGRICULTURE. 



several ditches in the central section of the marshes, near the 

 locality where my samples of subsoil water had been collected. 



These ditches had been dug quite recently upon the prop- 

 erty of Mr. Williams, of Boston, for improved drainage. 

 They consisted of several parallel sections, and amounted to 

 from four hundred and sixty to four hundred and seventy 

 rods in total length ; they were from three to five feet deep. 



The soil, when first removed, was more or less of a uniform 

 bluish-gray color ; after being exposed to the influence of the 

 air, it turned usually more yellowish ; in some places it became 

 red. This change was mainly due to an oxidation of the 

 protoxide of iron into sesquioxide. As the protoxide of iron 

 is known to be injurious to plant-life, good airing of the soil 

 in the marshes, by draining and subsequent ploughing, be- 

 comes indispensable for its successful cultivation in the interest 

 of a general system of mixed farming. 



The side-walls of the ditches furnished an excellent chance 

 to ascertain the peculiar character of the various layers which 

 constitute the soil within the central position of the marshes. 



The opinion expressed in my first report, — that the marsh- 

 lands would prove to be formed by numerous layers of 

 mineral matter, varying quite frequently, even within a com- 

 paratively confined area, widely in regard to the relative pro- 

 portion of the essential constituents, — was fully confirmed. 



A vertical section of the soil, to a depth of five feet, showed 

 also more or less extensive accumulations of vegetable matter, 

 resulting from different successive levels of growth, which 

 formed distinct layers, separated, not infrequently, by quite 

 different kinds of soil. 



The latter showed, in many instances, local accumulations 

 of sesquioxide of iron, which rendered the color of the soil, 

 within a limited area, bright red. The entire bulk of soil as 

 removed from the ditches, if properly mixed, deserved in 

 most instances to be called a good sandy ferruginous loam, 

 which, in its present state, is unusually rich in organic matter. 



In other localities, for instance, upon some of the cultivated 

 islands in the creek, the soil is of a black-brown color, and of 

 a fine pulverulent texture. 



The color in the latter case is mainly due to half-decom- 

 posed or humified organic matter. The various strata of soil 



