The climate, except in the marshy parts, is generally healthy.
The coastline is, in general, undefined and marshy, and broken into numerous bays and peninsulas.
The low ground between the slight hills flanking the Thames valley, and therefore mainly south of the present river, was originally occupied by a shallow lagoon of estuarine character, tidal, and interspersed with marshy tracts and certain islets of relatively firm land.
South of the Bermejo the land is more elevated and drier, though large depressions covered with marshy lagoons are to be found, similar to those farther north.
Pentandra), birch, and pine, when these grow in marshy places.