Regional Landscape Ecosystems of Michigan, Minnesota, and Wisconsin
SUBSECTION VI.3. Allegan
DISCUSSION: The subsection consists of a narrow band of dunes and flat lake plain along
SUB-SUBSECTIONS: Berrien Springs (VI.3.1), Southern Lake Michigan Lake Plain (VI.3.2), Jamestown (VI.3.3). (See figure 5.)
ELEVATION: 580 to 998 feet (177 to 304 m).
AREA: 2,656 square miles (6,882 sq km).
STATES: Michigan.
CLIMATE: Growing season ranges from 170 days in the south to 150 days in the north (Eichenlaub et al. 1990). Average annual precipitation ranges from 38 inches in the south to 32 inches in the north. Average snowfall ranges from 70 inches in the southern quarter of the subsection to as much as 100 inches farther north; this lake-effect snowfall decreases rapidly at the eastern edge of the subsection. Extreme minimum temperature ranges from -22½F at the southern edge to -34½F at the northern edge.
BEDROCK GEOLOGY: Subsection VI.3 is entirely underlain by Paleozoic bedrock; Devonian shale occurs in the southern quarter; and Mississippian shale, sandstone, and gypsum occur farther to the north (Dorr and Eschman 1984, Milstein 1987). Bedrock is generally covered with glacial deposits as thick as 350 feet, but there are local bedrock exposures in Sub-subsections VI.3.2 and VI.3.3 (Akers 1938).
LANDFORMS: Flat lake plain, coastal sand dunes, gently rolling till plain (ground moraine), and rolling to steep end moraines. See sub-subsections.
LAKES AND STREAMS: Very few lakes except for the kettle lakes in Sub-subsection VI.3.1. Large streams crossing the subsection include the Galien, St. Joseph, Kalamazoo, Grand, and Muskegon Rivers, all flowing into Lake Michigan.
SOILS: Soil textures range from sands to clays. The soils of the moraines (Sub-subsections VI.3.1 and VI.3.3) are classified as Hapludalfs plus Argiudolls (USDA Soil Conservation Service 1967). Lacustrine soils at the southern end of Sub-subsection VI.3.2 are classified as Udipsamments plus Hapludalf and Haplaquolls; further north the soils are Haplorthods plus Glossoboralfs. See sub-subsections.
PRESETTLEMENT VEGETATION: Most of the subsection was forested. See Sub-subsections.
NATURAL DISTURBANCE: See sub-subsections.
PRESENT VEGETATION AND LAND USE: See sub-subsections.
RARE PLANT COMMUNITIES: See sub-subsections.
RARE PLANTS: See sub-subsections.
RARE ANIMALS: See sub-subsections.
NATURAL AREAS: See sub-subsections.
PUBLIC LAND MANAGERS: See sub-subsections.
CONSERVATION CONCERNS: See sub-subsections.
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