458 BOTANICAL GAZETTE [DECEMBER 
submergence and draining of the bog removes so much of its con- 
tent that the surface may even slope down to a level considerably 
below that of low tide. Submerged deposits of fresh peat con- 
taining upright stumps, therefore, are not to be regarded as a 
conclusive proof of subsidence, either remote or recent. 
The salt marshes of a portion of our coast are underlaid by 
peat, often remarkably pure and reaching a depth of 6 meters or 
more, composed largely of the roots of Spartina patens and other 

- 5.—Settling of peaty land due to artificial lowering of Soca -water level 
in je phone of England; in 1848 the surface of the land was even with the top of 
the post. 
salt marsh grasses which grow only near the high tide level. In 
1862 Munce* called attention to this structure of the salt marshes 
along the New England coast, and showed that the deeply buried 
portions of the peat must have formed at high tide level. T heir 
present position he attributed to an undermining of the subsoil by 
fresh water, known by borings to descend from the upland and to 
pass through the sand found below a clay bed under the marsh 
*s MupcE, B. F., The salt marsh formations of Lynn. Essex Inst. Proc. 2#117~ 
IIg. 1862. 
