138 THE SOILS OF ST. MAEY's COUNTY 



to the action of the frost and air it becomes powdery and crumbly, and 

 is very much improved in texture. Drainage and liming should be 

 resorted to in order to produce this result on a large scale. 



The texture of this soil is shown by the analyses on Page 137. 



Tlie Swamp Land. 



There are three types of swamp lands in St. Mary's County — the tidal 

 flats, which are wholly or partially submerged at each high tide; the 

 fresh-water marshes, subject to frequent or constant inundation by 

 streams; and the fresh-water bogs ajid swamps, due to incomplete head- 

 water drainage or to natural or accidental artificial ponding of stream 

 waters. 



The salt marsh at the head of Chaptico Bay and the flats at the head 

 of Breton Bay are the most extensive examples of the first class occurring 

 in St. Mary's County. Except at especially high spring tides these 

 areas lie about 5 feet above the water level. They support a growth of 

 marsh grass and reeds and possess a silty soil mixed with partially decayed 

 vegetation. Some marsh hay is cut over these areas, and cattle and 

 hogs find pasture where the surface is sufficiently firm to support their 

 weight. 



These marshy areas are formed by the deposition of fine sand, silt, 

 and clay, brought down by streams and by the higher tides, together 

 with the decaying remains of the vegetation which gains a foothold on 

 the drier areas. These marshes are constantly growing in extent, and 

 in many instances cattle are feeding on marshy meadows where small- 

 sized boats floated in the early days of the colonization of the county. 

 Farther from the mouths of the larger tributary streams, above the 

 highest reach of the tide, the fresh-water marshes occur, as is the case 

 along the Chaptico Creek, Mcintosh Eun, and many of the streams 

 flowing into the Patuxent River. These marshes are similar to the 

 salt marshes, except that they are only subject to irregularly occurring 

 inundations below fresh water instead of periodic submersion by the 

 tides. 



The third class of swamps occupy positions at the heads of some of 



