ecological characterization atlas of coastal alabama - Data Center

The previously discussed Axis-Lafitte (6) and Dorovan-Johnston-Levy associations
(12) are also found along the coast of southern Mobile~County and just
inland in the Grand Bay Swamp, respectively .
The Fripp-Leon association (9) soils are deep soils along the coast and
include beach soils, sand dunes, and low, wet areas between dunes . Fripp
soils are deep, excessively drained sands . Leon soils are also composed of
sand, but are poorly drained and have a subsurface layer cemented together
wi th organic mat.eri al . These soi 1 s have 1 i mi ted agric ul tural val ue and are
used mainly for recreation .
The Bayou-Escambia-Harleston association (15) soils have loamy surface
layers and subsoils and are formed in marine and fluvial sediments on uplands
and terraces . Bayou soils occupy large flat areas that have poorly defined
drainage ways . Escambia and Harleston soils occupy slightly higher
elevations on gently undulating ridges . Bayou soils have a dark-gray sandy
loam surface with light-gray sandy loam or sandy clay loam subsoil . Escambia
and Harleston soils both have dark gray to olive fine sandy loam or loam
surface layers underlain by yellow, brown, gray, and red loam subsoils .
These areas are fai r for woodl and use . A,1 though some of the area i s used for
urban development it is poorly suited for it due to excessive wetness .
The Urban Land-Smithton-Benndale association (16) soils occupy the area
around the city of Mobile . These are level to gently rolling urban areas
interspersed with natural soils having loamy subsoils formed in loamy marine
and fluvial sediments on uplands . Urban land has such disturbed soil
profiles due to the construction of buildings, roads, and other structures
that identification of soils is usually impossible . Smithton soils are
poorly drained loamy soils on broad flat areas and along streams ; these soils
have grayish-brown and brownish-gray fine sandy loam surface overlying
brownish-gray fine sandy loam subsoils . Benndale soils are on ridgetops and
upper side slopes and are well drained . Benndale soils have dark grayishbrown
fi ne sandy 1 oam topsoi 1 underl ai n by yel l owi sh-brown or browni sh-yel l ow
loam or fine sandy loam subsoils . These areas are mostly urbanized or
committed to future urban use, and potential for other uses is poor .
The Southern Pine Hills is a southward sloping plain, moderately
dissected by streams, with subdued topography in the study area, although
there are sharp bluffs along the northeast shore of Mobile Bay . Along the
seaward margin, the escarpment lies parallel to the gulf and Mississippi
Sound fron which it turns northward and extends inland, forming subparallel
facing escarpments that follow the streams (Alabama Coastal Area Board 1978) .
The Southern Pine Hills subdivision of the Lower Coastal Plain within Baldwin
County is underlain by four basic types of shallow subsurface deposits :
marine terraces, and the Citronelle, Mobile Clay, and Ecor Rouge Formations
(Isphording 1977) .
Along the coast, in a strip about 24 km (15 mi) wide, are the marine
terraces of sand and clay deposited during Pleistocene times . They meet the
Recent coastal sand deposits to the south at elevations of 3 to 7 m (10 to 20
ft), and overlie the older Citronelle formation .
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