PLANTS ON SALT MARSHES. 241 



result from the mere washing of that portion of soil, which is 

 more or less permanently above the usual level of the subsoil 

 water of the marshes. The low percentage of chlorine, and 

 the relatively high percentage of sulphuric acid, indicate quite 

 plainly that a resolution of previously separated saline con- 

 stituents of the ocean, — containing for oln'ious reasons a 

 higher percentage of sulphate of lime, — could only have 

 caused its peculiar composition. These anal3'tical results are 

 quite encouraging ; for they prove, that in some localities at 

 least, a decidedly favorable change has been going on regard- 

 ing the composition of the subsoil water, and also that the 

 level of the latter has been actually and permanently lowered. 



Stagnant water prevents a rapid disintegration of mineral 

 and vegetable matter, by excluding the air; saltwater in- 

 creases that effect, particularly as far as the latter is concerned. 

 The beneficial influences of the freshening of the soil water, 

 and the permanent lowering of the water level within the 

 marshes, showed themselves during the past year in two con- 

 spicuous ways ; namely, first in a frequent change of the color 

 of the soil, wherever it had been brought above the former 

 general level of the water, and thereby under the unrestricted 

 influence of air and light. Second, in a more rapid decom- 

 position of the accumulated vegetable matter,, which under- 

 laid the present sod, and had served as its immediate 

 support. 



The frequent disappearance of grasses — as the native 

 "goose grass" and the seeded-down redtop and timothy — 

 from localities where they had prospered during the preceding 

 year, could be almost invariably traced to an exposure of 

 their roots in consequence of the decomposition of the 

 vegetable matter of preceding periods of vegetation, which 

 previously protected them against the extremes of the season. 

 The severe winter of 1874-75, and the drousfht durins; 

 the spring of 1875, had both fiivored their early extinction. 

 A luxuriant spontaneous growth of annual upland plants, 

 particularly oi everlasting ( Gna])]ialiumpolycej>halum, Mich.) , 

 was gradually taking their place. 



The change in the color of the soil was quite noticeable 

 everywhere along the recently exposed portion of the banks 

 of the creek ; it became, however, very conspicuous within 



31 



