The Sylvan plate. Relief from Copernicus GLO-30; rivers and lakes from USGS NHD; watersheds from the USGS Watershed Boundary Dataset; roads and city limits from Census TIGER 2024.
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Sylvan’s center stands about 1,030 ft above sea level. Within three miles the land runs from 1,010 ft to 1,100 ft, a difference of 90 ft: gently rolling country.
Under the town center the state geologic map shows Red beds (shale), from the Jurassic, 145 to 202 million years old.
The section below crosses 2 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 35×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Shale. Age: Jurassic, 145 to 202 million years old. About 13 mi of the line.
Sandstone, shale. Age: Carboniferous, 299 to 324 million years old. About 11 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale.
Heights from Copernicus GLO-90 (a surface model: it includes buildings and tree canopy); summits from USGS GNIS; rivers from USGS NHDPlus HR; rock from the USGS State Geologic Map Compilation.
A raindrop that lands in Sylvan reaches Lake Michigan by way of the Muskegon and the Middle Channel Muskegon: about 130 river miles. From there it moves on through the Great Lakes, over Niagara Falls and down the St. Lawrence to the Atlantic.
Lake on the way: Muskegon Lake.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Sylvan; river miles along the main stem, rounded.
