The Olin 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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Olin’s center stands about 760 ft above sea level. Within three miles the land runs from 730 ft to 870 ft, a difference of 140 ft: gently rolling country.
Under the town center the state geologic map shows Scotch Grove Formation (dolostone), from the Silurian, 431 to 440 million years old.
The section below crosses 3 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 59×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Dolostone. Age: Silurian, 431 to 440 million years old. About 17 mi of the line.
Dolostone. Age: Late Ordovician to Silurian, 434 to 447 million years old. About 4 mi of the line.
Dolostone, mudstone. Age: Silurian, 425 to 434 million years old. About 3 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 Olin reaches the Gulf of America by way of Walnut Creek, the Wapsipinicon and the Mississippi: about 1,560 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Olin; river miles along the main stem, rounded.
